353 results on '"Burkhardt F"'
Search Results
152. Enzymic and electrophoretic characterization of the hexachlorobenzene-induced cytochrome P-450 in the liver of rat
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Burkhardt, F., Goerz, G., and Vizethum, W.
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RATS ,CYTOCHROME P-450 ,ENZYMES ,HEXACHLOROBENZENE ,LIVER - Published
- 1980
153. Right ventricular strain in heart failure: Clinical perspective
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B. Pieske, Marijana Tadic, Carsten Tschöpe, Daniel A. Morris, Cesare Cuspidi, Franziska Burkhardt, Elisabeth Pieske-Kraigher, Ana Baudisch, Sabine Haßfeld, Tadic, M, Pieske Kraigher, E, Cuspidi, C, Morris, D, Burkhardt, F, Baudisch, A, Haßfeld, S, Tschöpe, C, and Pieske, B
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medicine.medical_specialty ,animal structures ,Heart Ventricles ,Ventricular Dysfunction, Right ,Population ,Déformation (strain) ,Heart failure ,Strain (injury) ,030204 cardiovascular system & hematology ,Ventricular Function, Left ,Insuffisance cardiaque à fraction d’éjection ventriculaire gauche préservée ,Strain ,Reduced ejection fraction ,03 medical and health sciences ,0302 clinical medicine ,Predictive Value of Tests ,Internal medicine ,medicine ,Humans ,In patient ,030212 general & internal medicine ,education ,Ventricular mechanics ,education.field_of_study ,Ejection fraction ,Ventricular Remodeling ,Ventricule droit ,business.industry ,Stroke Volume ,General Medicine ,Preserved ejection fraction ,Prognosis ,medicine.disease ,Myocardial Contraction ,Biomechanical Phenomena ,Insuffisance cardiaque ,medicine.anatomical_structure ,Echocardiography ,Ventricle ,Ventricular Function, Right ,Cardiology ,Right ventricle ,Heart-Assist Devices ,Stress, Mechanical ,Insuffisance cardiaque à fraction d’éjection ventriculaire gauche réduite ,Cardiology and Cardiovascular Medicine ,business ,Heart failure with preserved ejection fraction - Abstract
The number of studies demonstrating the importance of right ventricular remodelling in a wide range of cardiovascular diseases has increased in the past two decades. Speckle-tracking imaging provides new variables that give comprehensive information about right ventricular function and mechanics. In this review, we summarize current knowledge of right ventricular mechanics in heart failure with reduced ejection fraction and preserved ejection fraction. We searched PubMed, MEDLINE, Ovid and Embase databases for studies published from January 2000 to December 2016 in the English language using the following keywords: "right ventricle"; "strain"; "speckle tracking"; "heart failure with reduced ejection fraction"; and "heart failure with preserved ejection fraction". Investigations showed that right ventricular dysfunction is associated with higher cardiovascular and overall mortality in patients with heart failure, irrespective of ejection fraction. The number of studies investigating right ventricular strain in patients with heart failure with reduced ejection fraction is constantly increasing, whereas data on right ventricular mechanics in patients with heart failure with preserved ejection fraction are limited. Given the high feasibility, accuracy and clinical implications of right ventricular strain in the population with heart failure, it is of great importance to try to include the evaluation of right ventricular strain as a regular part of each echocardiographic examination in patients with heart failure. However, further investigations are necessary to establish right ventricular strain as a standard variable for decision-making.
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- 2017
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154. Right ventricular function and mechanics in chemotherapy- and radiotherapy-naïve cancer patients
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Philipp Attanasio, Ana Baudisch, Franziska Burkhardt, Burkert Pieske, Sabine Haßfeld, Frank R. Heinzel, Felicitas Escher, Martin Genger, Marijana Tadic, Cesare Cuspidi, Tadic, M, Baudisch, A, Haßfeld, S, Heinzel, F, Cuspidi, C, Burkhardt, F, Escher, F, Attanasio, P, Pieske, B, and Genger, M
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Male ,medicine.medical_treatment ,Ventricular Dysfunction, Right ,030204 cardiovascular system & hematology ,Left ventricular hypertrophy ,030218 nuclear medicine & medical imaging ,Free wall ,03 medical and health sciences ,0302 clinical medicine ,Diabetes mellitus ,Neoplasms ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Aged ,Retrospective Studies ,Chemotherapy ,Ventricular function ,business.industry ,Cancer ,Mechanics ,Middle Aged ,medicine.disease ,Radiation therapy ,Echocardiography ,Ventricular Function, Right ,Right ventricular function mechanics , chemotherapy ,Female ,Cardiology and Cardiovascular Medicine ,business ,Body mass index - Abstract
The present research evaluated right ventricular (RV) structure, function and mechanics in the cancer patients before initiation of chemo- or radiotherapy, and the association between cancer and decreased RV longitudinal strain. This retrospective investigation included 101 chemo- and radiotherapy-naive patients with solid cancer and 38 age- and gender-matched controls with similar cardiovascular risk profile. Echocardiographic examination and strain evaluation was performed in all participants. RV structure and RV systolic and diastolic function estimated with conventional echocardiographic parameters were similar between the cancer patients and controls. However, RV global longitudinal strain (− 22.7 ± 2.6% vs. − 21.1 ± 2.4%, p
- Published
- 2018
155. Emotional competence self-help app versus cognitive behavioural self-help app versus self-monitoring app to prevent depression in young adults with elevated risk (ECoWeB PREVENT): an international, multicentre, parallel, open-label, randomised controlled trial.
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Watkins ER, Warren FC, Newbold A, Hulme C, Cranston T, Aas B, Bear H, Botella C, Burkhardt F, Ehring T, Fazel M, Fontaine JRJ, Frost M, Garcia-Palacios A, Greimel E, Hößle C, Hovasapian A, Huyghe VEI, Karpouzis K, Löchner J, Molinari G, Pekrun R, Platt B, Rosenkranz T, Scherer KR, Schlegel K, Schuller BW, Schulte-Korne G, Suso-Ribera C, Voigt V, Voß M, and Taylor RS
- Abstract
Background: Effective, scalable interventions are needed to prevent poor mental health in young people. Although mental health apps can provide scalable prevention, few have been rigorously tested in high-powered trials built on models of healthy emotional functioning or tailored to individual profiles. We aimed to test a personalised emotional competence app versus a cognitive behavioural therapy (CBT) self-help app versus a self-monitoring app to prevent an increase in depression symptoms in young people., Methods: This multicentre, parallel, open-label, randomised controlled trial, within a cohort multiple randomised trial (including a parallel trial of wellbeing promotion) was done at four university trial sites in the UK, Germany, Spain, and Belgium. Participants were recruited from schools, universities, and social media from the four respective countries. Eligible participants were aged 16-22 years with increased vulnerability indexed by baseline emotional competence profile, without current or past diagnosis of major depression. Participants were randomly assigned (1:1:1) to usual practice plus either the personalised emotional competence self-help app, the generic CBT self-help app, or the self-monitoring app by an independent computerised system, minimised by country, age, and self-reported gender, and followed up for 12 months post-randomisation. Outcome assessors were masked to group allocation. The primary outcome was depression symptoms (according to Patient Health Questionnaire-9 [PHQ-9]) at 3-month follow-up, analysed in participants who completed the 3-month follow-up assessment. The study is registered with ClinicalTrials.gov, NCT04148508, and is closed., Findings: Between Oct 15, 2020, and Aug 3, 2021, 1262 participants were enrolled, including 417 to the emotional competence app, 423 to the CBT app, and 422 to the self-monitoring app. Mean age was 18·8 years (SD 2·0). Of 1262 participants self-reporting gender, 984 (78·0%) were female, 253 (20·0%) were male, 15 (1·2%) were neither, and ten (0·8%) were both. 178 participants in the emotional competence app group, 191 in the CBT app group, and 199 in the self-monitoring app group completed the follow-up assessment at 3 months. At 3 months, depression symptoms were lower with the CBT app than the self-monitoring app (mean difference in PHQ-9 -1·18 [95% CI -2·01 to -0·34]; p=0·006), but depression symptoms did not differ between the emotional competence app and the CBT app (0·63 [-0·22 to 1·49]; p=0·15) or the self-monitoring app and emotional competence app (-0·54 [-1·39 to 0·31]; p=0·21). 31 of the 541 participants who completed any of the follow-up assessments received treatment in hospital or were admitted to hospital for mental health-related reasons considered unrelated to interventions (eight in the emotional competence app group, 15 in the CBT app group, and eight in the self-monitoring app group). No deaths occurred., Interpretation: The CBT app delayed increases in depression symptoms in at-risk young people relative to the self-monitoring app, although this benefit faded by 12 months. Against hypotheses, the emotional competence app was not more effective at reducing depression symptoms than the self-monitoring app. CBT self-help apps might be valuable public mental health interventions for young people given their scalability, non-consumable nature, and affordability., Funding: European Commission., Competing Interests: Declaration of interests ERW reports royalties from Guilford Press for a CBT treatment manual he authored and is an expert member of the NICE Guidelines for treatment of adult depression. MFr is a founder and shareholder of Monsenso. BWS is a founder and shareholder of audEERING. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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156. Emotional competence self-help mobile phone app versus cognitive behavioural self-help app versus self-monitoring app to promote mental wellbeing in healthy young adults (ECoWeB PROMOTE): an international, multicentre, parallel, open-label, randomised controlled trial.
- Author
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Watkins ER, Warren FC, Newbold A, Hulme C, Cranston T, Aas B, Bear H, Botella C, Burkhardt F, Ehring T, Fazel M, Fontaine JRJ, Frost M, Garcia-Palacios A, Greimel E, Hößle C, Hovasapian A, Huyghe VEI, Karpouzis K, Löchner J, Molinari G, Pekrun R, Platt B, Rosenkranz T, Scherer KR, Schlegel K, Schuller BW, Schulte-Korne G, Suso-Ribera C, Voigt V, Voß M, and Taylor RS
- Abstract
Background: Based on evidence that mental health is more than an absence of mental disorders, there have been calls to find ways to promote flourishing at a population level, especially in young people, which requires effective and scalable interventions. Despite their potential for scalability, few mental wellbeing apps have been rigorously tested in high-powered trials, derived from models of healthy emotional functioning, or tailored to individual profiles. We aimed to test a personalised emotional competence self-help app versus a cognitive behavioural therapy (CBT) self-help app versus a self-monitoring app to promote mental wellbeing in healthy young people., Methods: This international, multicentre, parallel, open-label, randomised controlled trial within a cohort multiple randomised trial (including a parallel trial of depression prevention) was done at four university trial sites in four countries (the UK, Germany, Spain, and Belgium). Participants were recruited from schools and universities and via social media from the four respective countries. Eligible participants were aged 16-22 years with well adjusted emotional competence profiles and no current or past diagnosis of major depression. Participants were randomised (1:1:1) to usual practice plus either the emotional competence app, the CBT app or the self-monitoring app, by an independent computerised system, minimised by country, age, and self-reported gender, and followed up for 12 months post-randomisation. The primary outcome was mental wellbeing (indexed by the Warwick-Edinburgh Mental Well Being Scale [WEMWBS]) at 3-month follow-up, analysed in participants who completed the 3-month follow-up assessment. Outcome assessors were masked to group allocation. The study is registered with ClinicalTrials.gov, NCT04148508, and is closed., Findings: Between Oct 15, 2020, and Aug 3, 2021, 2532 participants were enrolled, and 847 were randomly assigned to the emotional competence app, 841 to the CBT app, and 844 to the self-monitoring app. Mean age was 19·2 years (SD 1·8). Of 2532 participants self-reporting gender, 1896 (74·9%) were female, 613 (24·2%) were male, 16 (0·6%) were neither, and seven (0·3%) were both. 425 participants in the emotional competence app group, 443 in the CT app group, and 447 in the self-monitoring app group completed the follow-up assessment at 3 months. There was no difference in mental wellbeing between the groups at 3 months (global p=0·47). The emotional competence app did not differ from the CBT app (mean difference in WEMWBS -0·21 [95% CI -1·08 to 0·66]) or the self-monitoring app (0·32 [-0·54 to 1·19]) and the CBT app did not differ from the self-monitoring app (0·53 [-0·33 to 1·39]). 14 of 1315 participants were admitted to or treated in hospital (or both) for mental health-related reasons, which were considered unrelated to the interventions (five participants in the emotional competence app group, eight in the CBT app group, and one in the self-monitoring app group). No deaths occurred., Interpretation: The emotional competence app and the CBT app provided limited benefit in promoting mental wellbeing in healthy young people. This finding might reflect the low intensity of these interventions and the difficulty improving mental wellbeing via universal digital interventions implemented in low-risk populations., Funding: European Commission., Competing Interests: Declaration of interests ERW receives royalties from Guilford Press for a CBT treatment manual he authored and was an expert member of the NICE Guidelines for treatment of adult depression. MFr is a founder and shareholder of Monsenso. BWS is a founder and shareholder of audEERING. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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157. 3D printed versus milled stabilization splints for the management of bruxism and temporomandibular disorders: study protocol for a randomized prospective single-blinded crossover trial.
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Rabel K, Lüchtenborg J, Linke M, Burkhardt F, Roesner AJ, Nold J, Vach K, Witkowski S, Hillebrecht AL, and Spies BC
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- Humans, Single-Blind Method, Prospective Studies, Treatment Outcome, Randomized Controlled Trials as Topic, Equivalence Trials as Topic, Pain Measurement, Adult, Printing, Three-Dimensional, Temporomandibular Joint Disorders therapy, Temporomandibular Joint Disorders diagnosis, Occlusal Splints, Cross-Over Studies, Bruxism therapy
- Abstract
Background: Nowadays, stabilization splints for the management of bruxism and temporomandibular disorders (TMD) can be produced utilizing a digital workflow comprising a digital impression of the teeth, digital splint design, and computer-aided manufacturing of the splints. The latter is usually a milling process, however, more recently 3D printing gained popularity due to its better cost and time efficiency. It remains unknown whether 3D printed stabilization splints are inferior to milled splints regarding clinical outcomes., Methods: This clinical trial assesses the non-inferiority of 3D printed occlusal splints compared to milled occlusal splints in a monocentric prospective randomized single-blinded crossover trial with two cohorts. One cohort includes 20 participants with bruxism, the other 20 participants with pain-related TMD, i.e., myalgia, myofascial pain, or arthralgia of the jaw muscles/the temporomandibular joint(s) diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Michigan-type stabilization splints are fabricated in a digital workflow by milling or 3D printing using CE-marked materials within their intended purpose. The participants wear a milled and a 3D printed splint in a randomized order for 3 months each, with follow-up visits after 2 weeks and 3 months. Investigated outcome parameters are oral health-related quality of life (OHRQoL) evaluated by the Oral Health Impact Profile (OHIP-G14), participant satisfaction as rated on a visual analog scale, therapeutic efficacy, and technical result of the splints. In this context, therapeutic efficacy means antagonist wear and-in the TMD group-reduction of pain/disability assessed by the Graded Chronic Pain Scale (GCPS v2.0) and clinical assessment following the DC/TMD standard, while technical outcome measures splint fit, wear and fracture rate., Discussion: The trial will provide important information on the clinical outcome of 3D printed stabilization splints in comparison to milled splints and will, therefore, enable an evidence-based decision in favor of or against a manufacturing process. This, in turn, will guarantee for a maximum of the patient's OHRQoL during splint therapy, therapeutic efficacy, and longevity of the splints., Trial Registration: German Clinical Trials Register (DRKS) DRKS00033904. Registered on March 15, 2024., (© 2024. The Author(s).)
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- 2024
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158. Dimensional accuracy and simulation-based optimization of polyolefins and biocopolyesters for extrusion-based additive manufacturing and steam sterilization.
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Burkhardt F, Schirmeister CG, Wesemann C, Baur L, Vach K, Nutini M, Licht EH, Metzger MC, Mülhaupt R, and Spies BC
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- Polyenes, Acrylic Resins chemistry, Sterilization, Steam, Polypropylenes
- Abstract
Polyolefins exhibit robust mechanical and chemical properties and can be applied in the medical field, e.g. for the manufacturing of dentures. Despite their wide range of applications, they are rarely used in extrusion-based printing due to their warpage tendency. The aim of this study was to investigate and reduce the warpage of polyolefins compared to commonly used filaments after additive manufacturing (AM) and sterilization using finite element simulation. Three types of filaments were investigated: a medical-grade polypropylene (PP), a glass-fiber reinforced polypropylene (PP-GF), and a biocopolyester (BE) filament, and they were compared to an acrylic resin (AR) for material jetting. Square specimens, standardized samples prone to warpage, and denture bases (n = 10 of each group), as clinically relevant and anatomically shaped reference, were digitized after AM and steam sterilization (134 °C). To determine warpage, the volume underneath the square specimens was calculated, while the deviations of the denture bases from the printing file were measured using root mean square (RMS) values. To reduce the warpage of the PP denture base, a simulation of the printing file based on thermomechanical calculations was performed. Statistical analysis was conducted using the Kruskal-Wallis test, followed by Dunn's test for multiple comparisons. The results showed that PP exhibited the greatest warpage of the square specimens after AM, while PP-GF, BE, and AR showed minimal warpage before sterilization. However, warpage increased for PP-GF, BE and AR during sterilization, whereas PP remained more stable. After AM, denture bases made of PP showed the highest warpage. Through simulation-based optimization, warpage of the PP denture base was successfully reduced by 25%. In contrast to the reference materials, PP demonstrated greater dimensional stability during sterilization, making it a potential alternative for medical applications. Nevertheless, reducing warpage during the cooling process after AM remains necessary, and simulation-based optimization holds promise in addressing this issue., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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159. Influence of sterilization on the retention forces of lithium disilicate and polymer-infiltrated ceramic-network crowns bonded to titanium base abutments: An in-vitro study.
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Laforì A, Sailer I, Fehmer V, Mojon P, Burkhardt F, and Pitta J
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- Dental Porcelain, Crowns, Materials Testing, Zirconium, Ceramics, Dental Stress Analysis, Dental Abutments, Computer-Aided Design, Titanium, Polymers
- Abstract
Objectives: The aim of this study was to evaluate the effect of sterilization on the retention forces of lithium disilicate (LD) and polymer-infiltrated ceramic network (PICN) crowns bonded to titanium base (Ti-base) abutments., Materials and Methods: Forty LD and 40 PICN crowns were milled and then bonded to 80 Ti-bases with two resin composite cements: Multilink Hybrid Abutment (mh) and Panavia V5 (pv) for a total of 8 groups (n = 10). Half of the specimens (test) underwent an autoclaving protocol (pressure 1.1 bar, 121°C, 20.5 min) and the other half not (control). Restorations were screw-retained to implants, and retention forces (N) were measured with a pull-off testing machine. The surfaces of the Ti-bases and the crowns were inspected for the analysis of the integrity of the marginal bonding interface and failure mode. Student's t-test, chi-square test, and univariate linear regression model were performed to analyze the data (α = 0.05)., Results: The mean pull-off retention forces ranged from 487.7 ± 73.4 N to 742.2 ± 150.3 N. Sterilized groups showed statistically significant overall higher maximum retention forces (p < .05), except for one combination (LD + mh). Sterilization led to an increased presence of marginal gaps and deformities compared to no-sterilization (p < .001), while no statistically significant relationship was found between failure mode and sterilization (p > .05)., Conclusions: Sterilization may have a beneficial effect on the retention forces of LD and PICN crowns bonded to titanium base abutments, although it may negatively influence the integrity of the marginal bonding interface., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
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- 2024
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160. Accuracy of additively manufactured and steam sterilized surgical guides by means of continuous liquid interface production, stereolithography, digital light processing, and fused filament fabrication.
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Burkhardt F, Handermann L, Rothlauf S, Gintaute A, Vach K, Spies BC, and Lüchtenborg J
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- Analysis of Variance, Cytoskeleton, Sterilization, Stereolithography, Steam
- Abstract
Different printing technologies can be used for prosthetically oriented implant placement, however the influence of different printing orientations and steam sterilization remains unclear. In particular, no data is available for the novel technology Continuous Liquid Interface Production. The objective was to evaluate the dimensional accuracy of surgical guides manufactured with different printing techniques in vertical and horizontal printing orientation before and after steam sterilization. A total of 80 surgical guides were manufactured by means of continuous liquid interface production (CLIP; material: Keyguide, Keyprint), digital light processing (DLP; material: Luxaprint Ortho, DMG), stereolithography (SLA; Surgical guide, Formlabs), and fused filament fabrication (FFF; material: Clear Base Support, Arfona) in vertical and horizontal printing orientation (n = 10 per subgroup). Spheres were included in the design to determine the coordinates of 17 reference points. Each specimen was digitized with a laboratory scanner after additive manufacturing (AM) and after steam sterilization (134 °C). To determine the accuracy, root mean square values (RMS) were calculated and coordinates of the reference points were recorded. Based on the measured coordinates, deviations of the reference points and relevant distances were calculated. Paired t-tests and one-way ANOVA were applied for statistical analysis (significance p < 0.05). After AM, all printing technologies showed comparable high accuracy, with an increased deviation in z-axis when printed horizontally. After sterilization, FFF printed surgical guides showed distinct warpage. The other subgroups showed no significant differences regarding the RMS of the corpus after steam sterilization (p > 0.05). Regarding reference points and distances, CLIP showed larger deviations compared to SLA in both printing orientations after steam sterilization, while DLP manufactured guides were the most dimensionally stable. In conclusion, the different printing technologies and orientations had little effect on the manufacturing accuracy of the surgical guides before sterilization. However, after sterilization, FFF surgical guides exhibited significant deformation making their clinical use impossible. CLIP showed larger deformations due to steam sterilization than the other photopolymerizing techniques, however, discrepancies may be considered within the range of clinical acceptance. The influence on the implant position remains to be evaluated., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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161. Reconstruction of dental roots for implant planning purposes: a retrospective computational and radiographic assessment of single-implant cases.
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Brandenburg LS, Georgii J, Schmelzeisen R, Spies BC, Burkhardt F, Fuessinger MA, Rothweiler RM, Gross C, Schlager S, and Metzger MC
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- Humans, Cone-Beam Computed Tomography, Retrospective Studies, Prostheses and Implants, Computer-Aided Design, Imaging, Three-Dimensional, Surgery, Computer-Assisted, Tooth, Dental Implants
- Abstract
Purpose: The aim of the study was to assess the deviation between clinical implant axes (CIA) determined by a surgeon during preoperative planning and reconstructed tooth axes (RTA) of missing teeth which were automatically computed by a previously introduced anatomical SSM., Methods: For this purpose all available planning datasets of single-implant cases of our clinic, which were planned with coDiagnostix Version 9.9 between 2018 and 2021, were collected for retrospective investigation. Informed consent was obtained. First, the intraoral scans of implant patients were annotated and subsequently analyzed using the SSM. The RTA, computed by the SSM, was then projected into the preoperative planning dataset. The amount and direction of spatial deviation between RTA and CIA were then measured., Results: Thirty-five patients were implemented. The mean distance between the occlusal entry point of anterior and posterior implants and the RTA was 0.99 mm ± 0.78 mm and 1.19 mm ± 0.55, respectively. The mean angular deviation between the CIA of anterior and posterior implants and the RTA was 12.4° ± 3.85° and 5.27° ± 2.97° respectively. The deviations in anterior implant cases were systematic and could be corrected by computing a modified RTA (mRTA) with decreased deviations (0.99 mm ± 0.84 and 4.62° ± 1.95°). The safety distances of implants set along the (m)RTA to neighboring teeth were maintained in 30 of 35 cases., Conclusion: The RTA estimated by the SSM revealed to be a viable implant axis for most of the posterior implant cases. As there are natural differences between the anatomical tooth axis and a desirable implant axis, modifications were necessary to correct the deviations which occurred in anterior implant cases. However, the presented approach is not applicable for clinical use and always requires manual optimization by the planning surgeon., (© 2023. The Author(s).)
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- 2024
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162. Retention and Marginal Integrity of CAD/CAM Fabricated Crowns Adhesively Cemented to Titanium Base Abutments-Influence of Bonding System and Restorative Material.
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Burkhardt F, Sailer I, Fehmer V, Mojon P, and Pitta J
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- Crowns, Ceramics, Resin Cements, Materials Testing, Zirconium, Computer-Aided Design, Dental Stress Analysis, Dental Abutments, Titanium, Dental Materials
- Abstract
Purpose: To assess the influence of the bonding system and restorative material on the marginal integrity and pull-off forces of monolithic all-ceramic crowns bonded to titanium base (ti-base) abutments., Materials and Methods: A total of 108 ti-bases were sandblasted and divided into nine experimental groups (n = 12) according to the combination of crown material (polymer-infiltrated ceramic-network [PI], lithium-disilicate [LD], and zirconia [ZI]) and bonding system (Multilink Hybrid-Abutment [MH], Panavia V5 [PV], RelyX Ul5mate [RU]) with the respective primers. After bonding the crowns to the ti-base abutments, the restorations were screw-retained on implants and thermomechanically aged (1,200,000 cycles, 49 N, 1.67 Hz, 5 to 55°C). Marginal integrity and bonding failures were evaluated under a light microscope, and pull-off forces (N) were calculated. Chi-square tests for marginal integrity as well as one-way and two-way ANOVA statistical tests for pull-off forces were applied (a = .05)., Results: PI presented higher marginal integrity than LD (P = .023). Bonding system PV revealed higher marginal integrity than MH (P =.005) and RU (P =.029). Differences in pull-off forces were found between restorative material and resin cements (P < .001), with the highest values for ZI + RU (598 ± 192 N), PI + PV (545 ± 114 N), LD + MH (532 ± 116 N), and PI + RU (528 ± 81 N). Specimens with marginal integrity revealed higher pull-off forces than those with alteration (P = .006). Specimens presenting bonding failures (micromovements) showed lower pull-off forces than those without bonding failures (P < .001)., Conclusions: The tested CAD/CAM materials show favorable bonding performances with different bonding systems, nevertheless for each restorative material a specific bonding system has to be recommended. Int J Prosthodont 2023;36:e88-e102.
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- 2023
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163. Systematic review evaluating the influence of the prosthetic material and prosthetic design on the clinical outcomes of implant-supported multi-unit fixed dental prosthesis in the posterior area.
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Pjetursson BE, Sailer I, Merino-Higuera E, Spies BC, Burkhardt F, and Karasan D
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- Prospective Studies, Retrospective Studies, Dental Porcelain, Ceramics, Zirconium, Crowns, Dental Prosthesis, Implant-Supported, Dental Prosthesis Design, Dental Restoration Failure
- Abstract
Objective: The objectives of the study were to assess the survival, failure, and technical complication rates of implant-supported fixed dental prosthesis (iFDPs) with pontic or splinted crown (iS
p C) designs in the posterior area and compare the influence of prosthetic materials and prosthetic design on the outcomes., Methods: Electronic and manual searches were performed to identify randomized-, prospective-, and retrospective clinical trials with follow-up time of ≥12 months, evaluating the clinical outcomes of posterior iFDPs with pontic or iSp Cs. Survival and complication rates were analyzed using robust Poisson's regression models., Results: Thirty-two studies reporting on 42 study arms were included in the present systematic review. The meta-analysis of the included studies indicated estimated 3-year survival rates of 98.3% (95%CI: 95.6-99.3%) for porcelain-fused-to-metal (PFM) iFDPs, 97.5% (95%CI: 95.5-98.7%) for veneered zirconia (Zr) iFDPs with pontic, 98.9% (95%CI: 96.8-99.6%) for monolithic or micro-veneered zirconia iFDPs with pontic, and 97.0% (95%CI: 84.8-99.9%) for lithium disilicate iFDPs with pontics. The survival rates for different material combination showed no statistically significant differences. Veneered restorations, overall, showed significantly (p < .01) higher ceramic fracture and chipping rates compared with monolithic restorations. Furthermore, there was no significant difference in survival rates (98.3% [95%CI: 95.6-99.3%] vs. 99.1% [95%CI: 97.6-99.7%]) and overall complication rates between PFM iFDPs with pontic and PFM iSp Cs., Conclusions: Based on the data identified by this systematic review, PFM, veneered Zr, and monolithic Zr iFDPs with pontic and iSp Cs showed similarly high short-term survival rates in the posterior area. Veneered restorations exhibit ceramic chipping more often than monolithic restorations, with the highest fracture rate reported for veneered Zr iFDPs., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)- Published
- 2023
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164. Dawn of the Transformer Era in Speech Emotion Recognition: Closing the Valence Gap.
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Wagner J, Triantafyllopoulos A, Wierstorf H, Schmitt M, Burkhardt F, Eyben F, and Schuller BW
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- Emotions, Machine Learning, Speech, Algorithms
- Abstract
Recent advances in transformer-based architectures have shown promise in several machine learning tasks. In the audio domain, such architectures have been successfully utilised in the field of speech emotion recognition (SER). However, existing works have not evaluated the influence of model size and pre-training data on downstream performance, and have shown limited attention to generalisation, robustness, fairness, and efficiency. The present contribution conducts a thorough analysis of these aspects on several pre-trained variants of wav2vec 2.0 and HuBERT that we fine-tuned on the dimensions arousal, dominance, and valence of MSP-Podcast, while additionally using IEMOCAP and MOSI to test cross-corpus generalisation. To the best of our knowledge, we obtain the top performance for valence prediction without use of explicit linguistic information, with a concordance correlation coefficient (CCC) of. 638 on MSP-Podcast. Our investigations reveal that transformer-based architectures are more robust compared to a CNN-based baseline and fair with respect to gender groups, but not towards individual speakers. Finally, we show that their success on valence is based on implicit linguistic information, which explains why they perform on-par with recent multimodal approaches that explicitly utilise textual information. To make our findings reproducible, we release the best performing model to the community.
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- 2023
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165. Influence of planning software and template design on the accuracy of static computer assisted implant surgery performed using guides fabricated with material extrusion technology: An in vitro study.
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Rothlauf S, Pieralli S, Wesemann C, Burkhardt F, Vach K, Kernen F, and Spies BC
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- Dental Implantation, Endosseous, Computer-Aided Design, Imaging, Three-Dimensional, Cone-Beam Computed Tomography, Software, Computers, Dental Implants
- Abstract
Objectives: This in vitro study aimed to assess the influence of the planning software and design of the surgical template on both trueness and precision of static computer assisted implant surgery (sCAIS) performed using guides fabricated using material extrusion (ME)., Methods: Three-dimensional radiographic and surface scans of a typodont were aligned using two planning software (coDiagnostiX, CDX; ImplantStudio, IST) to virtually position the two adjacent oral implants. Thereafter, surgical guides were fabricated with either an original (O) or modified (M) design with reduced occlusal support and were sterilized. Forty surgical guides were used to install 80 implants equally distributed amongst four groups: CDX-O, CDX-M, IST-O, and IST-M. Thereafter, the scan bodies were adapted to the implants and digitized. Finally, inspection software was used to assess discrepancies between the planned and final positions at the implant shoulder and main axis level. Multilevel mixed-effects generalised linear models were used for statistical analyses (p = 0.05)., Results: In terms of trueness, the largest average vertical deviations (0.29 ± 0.07 mm) were be assessed for CDX-M. Overall, vertical errors were dependant on the design (O < M; p ≤ 0.001). Furthermore, in horizontal direction, the largest mean discrepancy was 0.32 ± 0.09 mm (IST-O) and 0.31 ± 0.13 mm (CDX-M). CDX-O was superior compared to IST-O (p = 0.003) regarding horizontal trueness. The average deviations regarding the main implant axis ranged between 1.36 ± 0.41° (CDX-O) and 2.63 ± 0.87° (CDX-M). In terms of precision, mean standard deviation intervals of ≤ 0.12 mm (IST-O and -M) and ≤ 1.09° (CDX-M) were calculated., Conclusions: Implant installation with clinically acceptable deviations is possible with ME surgical guides. Both evaluated variables affected trueness and precision with negligible differences., Clinical Significance: The planning system and design influenced the accuracy of implant installation using ME-based surgical guides. Nevertheless, discrepancies were ≤ 0.32 mm and ≤ 2.63°, which may be considered within the range of clinical acceptance. ME should be further investigated as an alternative to the more expensive and time-consuming 3D printing technologies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)
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- 2023
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166. Long-Term Stability of Hydrothermally Aged and/or Dynamically Loaded One-Piece Diameter Reduced Zirconia Oral Implants.
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Kohal RJ, Trinkner A, Burkhardt F, Patzelt SBM, Vach K, Kušter M, Abram A, Kocjan A, and Nold J
- Abstract
The aim of this in vitro study was to evaluate the long-term stability of one-piece diameter reduced zirconia oral implants under the influence of loading and artificial aging in a chewing simulator as well as the fracture load in a static loading test. Thirty-two one-piece zirconia implants with a diameter of 3.6 mm were embedded according to the ISO 14801:2016 standard. The implants were divided into four groups of eight implants. The implants of group DLHT were dynamically loaded (DL) in a chewing simulator for 10
7 cycles with a load of 98 N and simultaneously hydrothermally aged (HT) using a hot water bath at 85 °C. Group DL was only subjected to dynamic loading and group HT was exclusively subjected to hydrothermal aging. Group 0 acted as a control group: no dynamical loading, no hydrothermal ageing. After exposure to the chewing simulator, the implants were statically loaded to fracture in a universal testing machine. To evaluate group differences in the fracture load and bending moments, a one-way ANOVA with Bonferroni correction for multiple testing was performed. The level of significance was set to p < 0.05. In the static loading test, group DLHT showed a mean fracture load of 511 N, group DL of 569 N, group HT of 588 N and control group 0 of 516 N. The average bending moments had the following values: DLHT: 283.5 Ncm; DL: 313.7 Ncm; HT: 324.4 Ncm; 0: 284.5 Ncm. No significant differences could be found between the groups. Hydrothermal aging and/or dynamic loading had no significant effect on the stability of the one-piece diameter reduced zirconia implants ( p > 0.05). Within the limits of this investigation, it can be concluded that dynamic loading, hydrothermal aging and the combination of loading and aging did not negatively influence the fracture load of the implant system. The artificial chewing results and the fracture load values indicate that the investigated implant system seems to be able to resist physiological chewing forces also over a long service period.- Published
- 2023
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167. One-Piece Zirconia Oral Implants for Single Tooth Replacement: Five-Year Results from a Prospective Cohort Study.
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Kohal RJ, Burkhardt F, Chevalier J, Patzelt SBM, and Butz F
- Abstract
The intention of this 5-year prospective cohort investigation was to clinically and radiographically investigate the outcomes of a one-piece zirconia implant system for single tooth replacement. Sixty-five patients received a total of 66 single-tooth implants. All implants immediately received temporary restorations and were finally restored with all-ceramic crowns. Follow-ups were performed at the prosthetic delivery, after 1, 3, and 5 years. Peri-implant and dental soft-tissue parameters were evaluated and patient-reported outcomes recorded. To monitor peri-implant bone remodelling, standardised radiographs were taken at the implant insertion and at the 1-, 3-, and 5-year follow-ups. In the course of 5 years, 14 implants were lost, resulting in a cumulative implant survival rate of 78.2%. The mean marginal bone loss from the implant insertion to the 5-year follow-up amounted to 1.12 mm. Probing depth, clinical attachment level, bleeding, and plaque index increased over time. In 91.5% of the implants, the papilla index showed levels of 1 or 2, respectively. At the end of the study, the patient satisfaction was higher compared to the pre-treatment measurements. Due to the low survival rate after five years and the noticeably high frequency of advanced bone loss observed in this study, the implant has not met the launch criteria, as it would have not been recommended for routine clinical use.
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- 2023
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168. Influence of loading and aging on the fracture strength of an injection-molded two-piece zirconia implant restored with a zirconia abutment.
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Kohal RJ, von Schierholz C, Nold J, Spies BC, Adolfsson E, Vach K, and Burkhardt F
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- Dental Implant-Abutment Design, Materials Testing, Titanium chemistry, Zirconium chemistry, Dental Stress Analysis, Dental Abutments, Dental Restoration Failure, Flexural Strength, Dental Implants
- Abstract
Objective: To investigate the fracture strength and potential phase transformation of an injection-molded two-piece zirconia implant restored with a zirconia abutment after loading and/or aging., Methods: Thirty-two two-piece zirconia implants (4.0 mm diameter) restored with zirconia abutments were embedded according to ISO 14801 and divided into four groups (n = 8/group): Three groups were either exclusively hydrothermally treated (group HT; 85°C), dynamically loaded (group DL; 10
7 cycles; 98 N), or subjected to both treatments simultaneously (group DL/HT). One group remained untreated (group 0). A sample from each group was cross-sectioned and examined by scanning electron microscopy for possible crystal phase transformation. The remaining samples were then loaded to fracture in a static loading test. A one-way ANOVA was used for statistical analyses., Results: During dynamic loading, three implants of group DL and six implants of group DL/HT fractured at a load of 98 N. The fracture strength of group DL/HT (108 ± 141 Ncm) was significantly reduced compared to the other groups (group 0: 342 ± 36 Ncm; HT: 363 ± 49 Ncm; DL: 264 ± 198 Ncm) (p < .05). Fractures from group 0 and HT occurred at both implant and abutment level, whereas implants from group DL and DL/HT fractured only at implant level. A shallow monoclinic transformation zone of approximately 2 μm was observed following hydrothermal treatment., Conclusions: Within the limitations of this study, it can be concluded that dynamic loading and the combination of loading and aging reduced the fracture strength of the implant abutment combination. Hydrothermal treatment caused a shallow transformation zone which had no influence on the fracture strength., (© 2022 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)- Published
- 2023
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169. One-Piece Zirconia Oral Implants for the Support of Three-Unit Fixed Dental Prostheses: Three-Year Results from a Prospective Case Series.
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Kohal RJ, Vach K, Butz F, Spies BC, Patzelt SBM, and Burkhardt F
- Abstract
The objective was to investigate the clinical and radiological outcome of one-piece zirconia oral implants to support three-unit fixed dental prostheses (FDP) after three years in function. Twenty-seven patients were treated with a total of 54 implants in a one-stage surgery and immediate provisionalization. Standardized radiographs were taken at implant placement, after one year and after three years, to evaluate peri-implant bone loss. Soft-tissue parameters were also assessed. Linear mixed regression models as well as Wilcoxon Signed Rank tests were used for analyzing differences between groups and time points (p < 0.05). At the three-year evaluation, one implant was lost, resulting in a cumulative survival rate of 98.1%. The mean marginal bone loss amounted to 2.16 mm. An implant success grade I of 52% (bone loss of ≤2 mm) and success grade II of 61% (bone loss of ≤3 mm) were achieved. None of the evaluated baseline parameters affected bone loss. The survival rate of the zirconia implants was comparable to market-available titanium implants. However, an increased marginal bone loss was observed with a high peri-implantitis incidence and a resulting low implant success rate.
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- 2023
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170. Creating an anatomical wax-up in partially edentulous patients by means of a statistical shape model.
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Brandenburg LS, Schwarz SJ, Spies BC, Weingart JV, Georgii J, Jung BA, Burkhardt F, Schlager S, and Metzger MC
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- Humans, Prosthodontics, Models, Statistical, Crowns, Dental Implants, Mouth, Edentulous
- Abstract
Purpose: Creating wax-ups of missing teeth for backward planning in implant surgery is a complex and time-consuming process. To facilitate implant-planning procedures, the automatic generation of a virtual wax-up would be useful. In the present study, the reconstruction of missing teeth in partially edentulous patients was performed automatically using newly developed software. The accuracy was investigated in order to test its clinical applicability., Materials and Methods: This study presents a new method for creating an automatic virtual wax-up, which could serve as a basic tool in modern implant-planning procedures. First, a statistical shape model (SSM) based on 76 maxillary and mandibular arch scans from dentally healthy individuals was generated. Then, artificially generated tooth gaps were reconstructed. The accuracy of the workflow was evaluated on a separate testing sample of 10 individuals with artificially created tooth gaps given as a median deviation, in millimeters. Scans of three clinical cases with partial edentulism were equally reconstructed using the SSM and compared with the final prosthodontic work., Results: The reconstruction of the artificial tooth gaps could be performed with the following median reconstruction accuracy: gap 21 with 0.15 mm; gap 27 with 0.20 mm; gap 34 with 0.22 mm: gap 36 with 0.22 mm; gaps 12 to 22 with 0.22 mm; gaps 34 to 36 with 0.22 mm. A scenario for an almost edentulous mandible with all teeth missing except teeth 33 and 43 could be reconstructed with a median reconstruction accuracy of 0.37 mm. The median tooth gap deviation of the SSM-based reconstruction in clinical cases differed from the final inserted prosthodontic teeth by 0.49 to 0.86 mm in median., Conclusion: A first feasibility of creating virtual wax-ups using an SSM could be shown. Artificially generated tooth gaps could be reconstructed close to the original with the proposed workflow. In the clinical cases, the SSM proposes an anatomical reconstruction, which does not yet consider prosthodontic aspects. To obtain clinical use, contact with antagonist teeth must be considered and more training data must be implemented. However, the presented method offers a fast and viable way for the approximate placement of missing crowns. This could be used in a digital planning workflow when implant position must be determined. (Int J Comput Dent 2022;25(4):349-0; doi: 10.3290/j.ijcd.b2599407).
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- 2022
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171. Reconstruction of dental roots for implant planning purposes: a feasibility study.
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Brandenburg LS, Berger L, Schwarz SJ, Meine H, Weingart JV, Steybe D, Spies BC, Burkhardt F, Schlager S, and Metzger MC
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- Computer-Aided Design, Cone-Beam Computed Tomography methods, Feasibility Studies, Humans, Imaging, Three-Dimensional, Mandible, Maxilla, Dental Implants, Surgery, Computer-Assisted methods
- Abstract
Purpose: Modern virtual implant planning is a time-consuming procedure, requiring a careful assessment of prosthetic and anatomical factors within a three-dimensional dataset. In order to facilitate the planning process and provide additional information, this study examines a statistical shape model (SSM) to compute the course of dental roots based on a surface scan., Material and Methods: Plaster models of orthognathic patients were scanned and superimposed with three-dimensional data of a cone-beam computer tomography (CBCT). Based on the open-source software "R", including the packages Morpho, mesheR, Rvcg and RvtkStatismo, an SSM was generated to estimate the tooth axes. The accuracy of the calculated tooth axes was determined using a leave-one-out cross-validation. The deviation of tooth axis prediction in terms of angle or horizontal shift is described with mean and standard deviation. The planning dataset of an implant surgery patient was additionally analyzed using the SSM., Results: 71 datasets were included in this study. The mean angle between the estimated tooth-axis and the actual tooth-axis was 7.5 ± 4.3° in the upper jaw and 6.7 ± 3.8° in the lower jaw. The horizontal deviation between the tooth axis and estimated axis was 1.3 ± 0.8 mm close to the cementoenamel junction, and 0.7 ± 0.5 mm in the apical third of the root. Results for models with one missing tooth did not differ significantly. In the clinical dataset, the SSM could give a reasonable aid for implant positioning., Conclusions: With the presented SSM, the approximate course of dental roots can be predicted based on a surface scan. There was no difference in predicting the tooth axis of existent or missing teeth. In clinical context, the estimation of tooth axes of missing teeth could serve as a reference for implant positioning. However, a higher number of training data must be achieved to obtain increasing accuracy., (© 2022. The Author(s).)
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- 2022
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172. Cytotoxicity of polymers intended for the extrusion-based additive manufacturing of surgical guides.
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Burkhardt F, Spies BC, Wesemann C, Schirmeister CG, Licht EH, Beuer F, Steinberg T, and Pieralli S
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- Gingiva, Humans, Keratinocytes, Polypropylenes toxicity, Polymers, Stereolithography
- Abstract
Extrusion-based printing enables simplified and economic manufacturing of surgical guides for oral implant placement. Therefore, the cytotoxicity of a biocopolyester (BE) and a polypropylene (PP), intended for the fused filament fabrication of surgical guides was evaluated. For comparison, a medically certified resin based on methacrylic esters (ME) was printed by stereolithography (n = 18 each group). Human gingival keratinocytes (HGK) were exposed to eluates of the tested materials and an impedance measurement and a tetrazolium assay (MTT) were performed. Modulations in gene expression were analyzed by quantitative PCR. One-way ANOVA with post-hoc Tukey tests were applied. None of the materials exceeded the threshold for cytotoxicity (< 70% viability in MTT) according to ISO 10993-5:2009. The impedance-based cell indices for PP and BE, reflecting cell proliferation, showed little deviations from the control, while ME caused a reduction of up to 45% after 72 h. PCR analysis after 72 h revealed only marginal modulations caused by BE while PP induced a down-regulation of genes encoding for inflammation and apoptosis (p < 0.05). In contrast, the 72 h ME eluate caused an up-regulation of these genes (p < 0.01). All evaluated materials can be considered biocompatible in vitro for short-term application. However, long-term contact to ME might induce (pro-)apoptotic/(pro-)inflammatory responses in HGK., (© 2022. The Author(s).)
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- 2022
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173. A Novel Method for Digital Reconstruction of the Mucogingival Borderline in Optical Scans of Dental Plaster Casts.
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Brandenburg LS, Schlager S, Harzig LS, Steybe D, Rothweiler RM, Burkhardt F, Spies BC, Georgii J, and Metzger MC
- Abstract
Adequate soft-tissue dimensions have been shown to be crucial for the long-term success of dental implants. To date, there is evidence that placement of dental implants should only be conducted in an area covered with attached gingiva. Modern implant planning software does not visualize soft-tissue dimensions. This study aims to calculate the course of the mucogingival borderline (MG-BL) using statistical shape models (SSM). Visualization of the MG-BL allows the practitioner to consider the soft tissue supply during implant planning. To deploy an SSM of the MG-BL, healthy individuals were examined and the intra-oral anatomy was captured using an intra-oral scanner (IOS). The empirical anatomical data was superimposed and analyzed by principal component analysis. Using a Leave-One-Out Cross Validation (LOOCV), the prediction of the SSM was compared with the original anatomy extracted from IOS. The median error for MG-BL reconstruction was 1.06 mm (0.49-2.15 mm) and 0.81 mm (0.38-1.54 mm) for the maxilla and mandible, respectively. While this method forgoes any technical work or additional patient examination, it represents an effective and digital method for the depiction of soft-tissue dimensions. To achieve clinical applicability, a higher number of datasets has to be implemented in the SSM.
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- 2022
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174. Fracture resistance and crystal phase transformation of a one- and a two-piece zirconia implant with and without simultaneous loading and aging-An in vitro study.
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Burkhardt F, Spies BC, Riemer L, Adolfsson E, Doerken S, and Kohal RJ
- Subjects
- Dental Abutments, Dental Implant-Abutment Design, Dental Restoration Failure, Dental Stress Analysis, Materials Testing, Titanium, Dental Implants, Zirconium
- Abstract
Objective: To evaluate the influence of artificial aging on the transformation propagation and fracture resistance of zirconia implants., Methods: One-piece (with integrated implant abutment, 1P; regular diameter [4.1mm]; n = 16) and two-piece (with separate implant abutment, 2P; wide diameter [5 mm]; n = 16) zirconia implants were embedded according to ISO 14801. A two-piece titanium-zirconium implant (Ti-Zr; 4.1 mm diameter) served as a control (n = 16). One subgroup (n = 8) of each system was simultaneously dynamically loaded (10
7 cycles; 98N) and hydrothermally aged (85°C, 58 days), while the other subgroup (n = 8) remained untreated. Finally, specimens were statically loaded to fracture. Potential crystal phase transformation was examined at cross sections using scanning electron microscopy (SEM). A multivariate linear regression model was applied for statistical analyses., Results: The fracture resistance of 1P (1,117 [SD = 38] N; loaded/aged: 1,009 [60] N), 2P (850 [36] N; loaded/aged: 799 [84] N), and Ti-Zr implants (1,338 [205] N; loaded/aged: 1,319 [247] N) was not affected significantly by loading/aging (p = .171). However, when comparing the systems, they revealed significant differences independent of loading/aging (p ≤ .001). Regarding the crystal structure, a transformation zone was observed in SEM images of 1P only after aging, while 2P showed a transformation zone even before aging. After hydrothermal treatment, an increase of this monoclinic layer was observed in both systems., Conclusions: The Ti-Zr control implant showed higher fracture resistance compared to both zirconia implants. Loading/aging had no significant impact on the fracture resistance of both zirconia implants. The wide-body 2P zirconia implant was weaker than the regular body 1P implant., (© 2021 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)- Published
- 2021
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175. Design of customized soft-tissue substitutes for posterior single-tooth defects: A proof-of-concept in-vitro study.
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Sun Y, Yu T, Strasding M, Liu X, Burkhardt F, Schäfer B, Sailer I, and Nesic D
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- Computer-Aided Design, Esthetics, Dental, Humans, Mandible surgery, Maxilla surgery, Alveolar Ridge Augmentation, Tooth
- Abstract
Objectives: Soft-tissue volume augmentation treatments do not provide the satisfactory long-term functional and esthetic outcomes. The aim of the study was to develop a standardized digital procedure to design individual soft-tissue substitutes (STS) and apply mathematical modeling to obtain average shape STS for single posterior tooth defects., Material and Methods: Thirty-three casts from 30 patients were scanned. STS were designed with a computer-aided design software and a systematic procedure standardized the measurements across all STS using 3D-analysis software. The occlusal, mesial-distal, and buccal-lingual planes were defined to partition, each STS and produce a mesh. The thickness values of each 3D slice were documented in a coordinate system chart to generate a scatter graph. Graphs were embedded into images (Orange software) and images were analyzed via hierarchical clustering., Results: Three STS groups were identified according to shape. Two shapes corresponded to the maxilla defects: a square (n = 13) with dimensions of 10 mm in a lingual-buccal (length) and 7-10 mm in a mesial-distal (width) direction; a rectangle (n = 11) of 11 mm in length and 4-7 mm in width. The average shape for mandible defects (n = 9) was smaller (6-8 mm in length, 5-10 mm in width). The highest thickness in all STS was in the buccal portion, above the alveolar ridge, with median values of 2 mm. The lowest thickness of 0.2 mm was at the edges., Conclusions: The study developed novel methodology to design customized, as well as average shape STS for volume augmentation. Future STS harboring adapted geometry might increase volume augmentation efficiency and accuracy, while reducing surgical time., (© 2021 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)
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- 2021
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176. Effect of airborne-particle abrasion of a titanium base abutment on the stability of the bonded interface and retention forces of crowns after artificial aging.
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Pitta J, Burkhardt F, Mekki M, Fehmer V, Mojon P, and Sailer I
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- Crowns, Dental Etching, Dental Stress Analysis, Materials Testing, Resin Cements, Surface Properties, Zirconium, Dental Bonding, Titanium
- Abstract
Statement of Problem: Published data have shown that a mechanical surface treatment of titanium surfaces increases bonding potential. However, most of the studies are based on shear or tensile tests performed on flat-surfaced specimens and do not take into consideration the retention given by the titanium base (ti-base) axial walls and the thermomechanical loading seen in a clinical setting., Purpose: The purpose of this in vitro study was to evaluate the influence of different airborne-particle abrasion (APA) methods of the ti-base surface on the stability of the bonded interface and retention forces between these titanium bases and lithium disilicate crowns after thermomechanical aging., Material and Methods: Sixty internal connection implants (Conelog) were restored with lithium disilicate crowns and bonded to the corresponding ti-bases (Conelog). The ti-bases were divided into 4 groups (n=15), 3 experimental groups applying different APA methods, 30-μm silica-modified Al
2 O3 particles (CoJet) (30-SiO-AlO), 50-μm Al2 O3 (Cobra Aluoxyd) (50-AlO), 110-μm silica-modified Al2 O3 particles (Rocatec Plus) (110-SiO-AlO), and 1 control group (NoT). Ti-bases were airborne-particle abraded (10 seconds, 0.25 MPa at a 10-mm distance) under standardized conditions in a custom-made APA device. All crowns were cemented with a resin cement (Multilink Hybrid Abutment). After aging (1 200 000 cycles, 49 N, 1.67 Hz; 5 °C-55 °C, 120 seconds), all specimens were assessed for the presence of bond failures by optical microscopy (×50). The retention forces (N) were tested by using a pull-off test (0.5mm/min). Modes of failure were classified (Type 1, 2, or 3). An additional ti-base representing each group was prepared for surface roughness (μm) calculation (Ra, Rc, Rz) with a noncontact laser profilometer, and representative scanning electron microscope (SEM) images were recorded (×1000). Chi-squared tests were performed to analyze the bonded interface failure and modes of failure, and a Kruskal-Wallis test was selected to evaluate retention force values (α=.05)., Results: The percentages of bonding failure after aging were 73.3% (NoT), 40% (30-SiO-AlO), 6.7% (50-AlO), and 40% (110-SiO-AlO). The stability of the bonded interface was influenced by the APA method applied (P<.05). Mean ±standard deviation retention force values varied from 206.3 ±86.3 N (NoT) to 420 ±139.5 N (50-AlO), and the differences between these 2 groups were significant (P<.05). Modes of failure were predominantly Type 2 (30-SiO-AlO; 50-AlO; 110-SiO-AlO) and Type 3 (NoT)., Conclusions: Airborne-particle abrasion of the titanium surface increased the bond stability and retention forces between the ti-base and the respective crown. The use of 50-μm Al2 O3 provided the most stable bonded interface among the different treatments., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)- Published
- 2021
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177. Retention Forces of Monolithic CAD/CAM Crowns Adhesively Cemented to Titanium Base Abutments-Effect of Saliva Contamination Followed by Cleaning of the Titanium Bond Surface.
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Burkhardt F, Pitta J, Fehmer V, Mojon P, and Sailer I
- Abstract
The aim of this study was to investigate the effects of saliva contamination and the cleaning of the bond surface of titanium base (ti-base) abutments on the bonding stability and retention force values. The bond surface of the ti-base abutments was treated with airborne-particle abrasion. After contamination, the ti-base abutments underwent different cleaning protocols: water spray (H
2 O); alcohol (ALC); suspension of zirconium particles (SZP); reapplied airborne-particle abrasion (APA); and a control condition without contamination and cleaning (CTR). All lithium disilicate crowns were bonded to the ti-base abutments using a primer and a self-curing composite. Bonded specimens underwent thermo-mechanical aging. Bond failure analysis and pull-off testing were performed. Bond failure occurred more frequently in groups H2 O, ALC, SZP, and APA ( p < 0.05). Significant differences in retention force values were only found between CTR and ALC ( p < 0.05). Specimens which did not show bond failure after ageing had higher retention force values than the specimens that showed bond failure ( p < 0.05). Saliva contamination with cleaning can degrade the bonding properties to titanium. For the retention force values, only the protocol with alcohol after contamination could not restore the values.- Published
- 2021
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178. Bond strength of conventional, subtractive, and additive manufactured denture bases to soft and hard relining materials.
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Wemken G, Burkhardt F, Spies BC, Kleinvogel L, Adali U, Sterzenbach G, Beuer F, and Wesemann C
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- Acrylic Resins, Denture Bases, Materials Testing, Surface Properties, Tensile Strength, Dental Bonding, Denture Liners
- Abstract
Objective: To investigate the tensile and flexural strength of poured, subtractive, and additive manufactured denture base methacrylates bonded to soft and hard relining materials after hydrothermal cycling and microwave irradiation., Methods: This study included a conventional (CB), subtractive (SB), and additive (AB) base material as well as a soft (SCR) and hard (HCR) chairside and one hard laboratory-side (HLR) relining material. Reference bodies of the base materials and bonded specimens to the relining materials were produced with a rectangular cross-section. The specimens were either pre-treated by water storage (50 h, 37 °C), hydrothermal cycling (5000 cycles, 5 °C and 55 °C, 30 s each), or microwave irradiation (6 cycles, 640 W, 3 min, wet). A tensile and four-point bending test were performed for a total of 504 specimens. Data were analysed using multivariate analysis of variance (MANOVA) with post-hoc Tukey tests (α = 0.05)., Results: In comparison with the other reference groups SB showed marginally higher tensile and flexural strength (p < 0.047). Bond strength to SCR was affected neither by the base material nor by the pre-treatment (p > 0.085). HCR demonstrated twice the bond strength to AB compared with SB and CB (p ≤ 0.001). HLR showed the highest bond strength to CB (p ≤ 0.001). There was no difference between the specimens after hydrothermally cycling and microwave irradiation (p > 0.318)., Significance: The bond strength of hard relining materials to subtractive and additive manufactured denture bases differ compared with conventional pouring., (Copyright © 2021 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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179. A Novel Zirconia-Based Composite Presents an Aging Resistant Material for Narrow-Diameter Ceramic Implants.
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Burkhardt F, Harlass M, Adolfsson E, Vach K, Spies BC, and Kohal RJ
- Abstract
A novel ceria-stabilized zirconia-alumina-aluminate composite (Ce-TZP-comp) that is not prone to aging presents a potential alternative to yttrium-stabilized zirconia for ceramic oral implants. The objective of this study was to evaluate the long-term stability of a one-piece narrow-diameter implant made of Ce-TZP-comp. Implant prototypes with a narrow (3.4 mm) and regular (4.0 mm) diameter were embedded according to ISO 14801, and subgroups (n = 8) were subsequently exposed to dynamic loading (10
7 cycles, 98N) and/or hydrothermal treatment (aging, 85 °C). Loading/aging was only applied as a combined protocol for the 4.0 mm diameter implants. One subgroup of each diameter remained untreated. One sample was cross-sectioned from each subgroup and evaluated with a scanning electron microscope for phase-transformation of the lattice. Finally, the remaining samples were loaded to fracture. A multivariate linear regression model was applied for statistical analyses (significance at p < 0.05). All samples withstood the different loading/aging protocols and no transformation propagation was observed. The narrow diameter implants showed the lowest fracture load after combined loading/aging (628 ± 56 N; p < 0.01), whereas all other subgroups exhibited no significantly reduced fracture resistance (between 762 ± 62 and 806 ± 73 N; p > 0.05). Therefore, fracture load values of Ce-TZP-comp implants suggest a reliable intraoral clinical application in the anterior jaw regions.- Published
- 2021
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180. Low-dose Bisphenol A and its analogues Bisphenol F and S activate estrogen receptor ß and slightly modulate genes in human gingival keratinocytes.
- Author
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Burkhardt F, Schulz SD, Hellwig E, Vach K, Tomakidi P, and Polydorou O
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- Humans, Keratinocytes, Phenols, Benzhydryl Compounds toxicity, Receptors, Estrogen
- Abstract
Objectives: This study investigated the putative activation of estrogen receptor β (ERβ) and possible effects related on gene expression in oral mucosal cells in response to the endocrine disruptor Bisphenol A (BPA) and its analogues Bisphenol F (BPF) and Bisphenol S (BPS)., Methods: Human gingival keratinocytes (HGK) were exposed to BPA-, BPF-, and BPS-solutions in concentrations of 1.3 μM, 0.16 μM and 11.4 nM as well as 200 pM and 100 nM estradiol (E
2 ) for 6 h, 24 h and 4 d. Indirect immunofluorescence (IIF) was performed to detect a possible ERβ activation. Additionally, transcription of keratinocyte-relevant biomarkers was analyzed by quantitative real-time PCR (qRT-PCR). A linear mixed model and pairwise comparisons were applied for statistical analyses., Results: The tested concentrations of BPA, BPF, BPS and E2 revealed distinct activation of ERβ at all time periods, whereat 100 nM E2 induced the most pronounced activation. Despite the detected ERβ activation, the concentrations of BPA and its analogues induced only moderate modulation of the tested keratinocyte-relevant biomarker genes at all time periods. This also applied to 200 pM E2 , while in case of 100 nM E2 significant changes (p < 0.05) were detected for almost all analyzed genes., Significance: Though BPA and its analogues induce activation of ERß irrespective from the chosen concentrations and incubation periods, they lack significant modulation of gene expression of keratinocyte-relevant biomarkers. Although limited to a selected number of genes, the sparse modulation of gene expression may give a hint that the substances do slightly affect transcription of gingival-keratinocyte-innate genes, since the concentrations applied to HGK were of physiological importance., (Copyright © 2021 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)- Published
- 2021
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181. Mechanical stability and technical outcomes of monolithic CAD/CAM fabricated abutment-crowns supported by titanium bases: An in vitro study.
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Pitta J, Hjerppe J, Burkhardt F, Fehmer V, Mojon P, and Sailer I
- Subjects
- Ceramics, Computer-Aided Design, Crowns, Dental Porcelain, Dental Stress Analysis, Materials Testing, Zirconium, Dental Implant-Abutment Design, Titanium
- Abstract
Objectives: To evaluate mechanical stability (survival and complication rates) and bending moments of different all-ceramic monolithic restorations bonded to titanium bases (hybrid abutment-crowns) or to customized titanium abutments compared to porcelain-fused-to-metal crowns (PFM) after thermo-mechanical aging., Material and Methods: Sixty conical connection implants (4.3 mm-diameter) were divided in five groups (n = 12): PFM using gold abutment (GAbut-PFM), lithium disilicate crown bonded to customized titanium abutment (TAbut+LDS), lithium disilicate abutment-crown bonded to titanium base (TiBase+LDS), zirconia abutment-crown bonded to titanium base (TiBase+ZR), polymer-infiltrated ceramic-network (PICN) abutment-crown bonded to titanium base (TiBase+PICN). Simultaneous thermocycling (5°-55°C) and chewing simulation (1,200,000-cycles, 49 N, 1.67 Hz) were applied. Catastrophic and non-catastrophic events were evaluated under light microscope, and survival and complication rates were calculated. Specimens that survived aging were loaded until failure and bending moments were calculated., Results: Survival rates after aging were 100% (TAbut+LDS, TiBase+LDS), 91.7% (GA-PFM), 66.7% (TiBase+ZR) and 58.3% (TiBase+PICN) and differed among the groups (p = .006). Non-catastrophic events as screw loosening (GA-PFM) and loss of retention or micro-/macro-movement (TiBase groups) were observed. Complication rates varied among the groups (p < .001). TiBase+PICN had lower bending moment than all the other groups (p < .001)., Conclusions: Hybrid abutment-crowns made of lithium disilicate can be an alternative to PFM-based restorations, although concerns regarding the bonded interface between the titanium base and abutment-crown can be raised. PICN and zirconia may not be recommended due to its inferior mechanical and bonding outcomes, respectively. Titanium customized abutment with bonded lithium disilicate crown appears to be the most stable combination., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2021
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182. Pandemic-Driven Development of a Medical-Grade, Economic and Decentralized Applicable Polyolefin Filament for Additive Fused Filament Fabrication.
- Author
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Burkhardt F, Schirmeister CG, Wesemann C, Nutini M, Pieralli S, Licht EH, Metzger M, Wenz F, Mülhaupt R, and Spies BC
- Subjects
- Humans, Personal Protective Equipment, Polypropylenes chemistry, Printing, Three-Dimensional, Polyenes chemistry, Polymers chemistry
- Abstract
A polyolefin with certified biocompatibility according to USP class VI was used by our group as feedstock for filament-based 3D printing to meet the highest medical standards in order to print personal protective equipment for our university hospital during the ongoing pandemic. Besides the chemical resistance and durability, as well as the ability to withstand steam sterilization, this polypropylene (PP) copolymer is characterized by its high purity, as achieved by highly efficient and selective catalytic polymerization. As the PP copolymer is suited to be printed with all common printers in fused filament fabrication (FFF), it offers an eco-friendly cost-benefit ratio, even for large-scale production. In addition, a digital workflow was established focusing on common desktop FFF printers in the medical sector. It comprises the simulation-based optimization of personalized print objects, considering the inherent material properties such as warping tendency, through to validation of the process chain by 3D scanning, sterilization, and biocompatibility analysis of the printed part. This combination of digital data processing and 3D printing with a sustainable and medically certified material showed great promise in establishing decentralized additive manufacturing in everyday hospital life to meet peaks in demand, supply bottlenecks, and enhanced personalized patient treatment.
- Published
- 2020
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183. Temporary Implant-Supported Single Crowns Using Titanium Base Abutments: An In Vitro Study on Bonding Stability and Pull-out Forces.
- Author
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Pitta J, Bijelic-Donova J, Burkhardt F, Fehmer V, Närhi T, and Sailer I
- Subjects
- Computer-Aided Design, Crowns, Dental Abutments, Dental Stress Analysis, Materials Testing, Resin Cements, Zirconium, Dental Implants, Titanium
- Abstract
Purpose: To evaluate the effect of cementation protocols on the bonding interface stability and pull-out forces of temporary implant-supported crowns bonded on a titanium base abutment (TiB) or on a temporary titanium abutment (TiA)., Materials and Methods: A total of 60 implants were restored with PMMA-based CAD/CAM crowns. Five groups (n = 12) were created: Group 1 = TiB/SRc: crown conditioned with MMA-based liquid (SR Connect, Ivoclar Vivadent); Group 2 = TiB/50Al-MB: crown airborne particle-abraded with 50-μm Al
2 O3 and silanized (Monobond Plus, Ivoclar Vivadent); Group 3 = TiB/30SiOAl-SRc: crown airborne particle-abraded with 30-μm silica-coated Al2 O3 (CoJet, 3M ESPE) and conditioned with MMA-based liquid (SR Connect); Group 4 = TiB/30SiOAl-MB: crown airborne particle-abraded with 30- μm silica-coated Al2 O3 (CoJet) and silanized (Monobond Plus); and Group 5 = TiA/TA-PMMA: crown manually enlarged, activated, and rebased with PMMA resin (Telio Lab, Ivoclar Vivadent). Specimens in the TiB groups were cemented using a resin cement (Multilink Hybrid Abutment, Ivoclar Vivadent). After aging (120,000 cycles, 49 N, 1.67 Hz, 5°C to 55°C, 120 seconds), bonding interface failure was analyzed (50x). Pull-out forces (N) (0.5 mm/minute) and modes of failure were registered. Chi-square and Kruskal-Wallis tests were used to analyze the data (α = .05)., Results: Bonding failure after aging varied from 0% (Group 5) to 100% (Groups 1, 2, and 4) (P < .001). Mean pull-out force ranged between 53.1 N (Group 1) and 1,146.5 N (Group 5). The pull-off forces were significantly greater for Group 5 (P < .05), followed by Group 3 (P < .05), whereas the differences among the remaining groups were not significant (P > .05)., Conclusion: The cementation protocol had an effect on the bonding interface stability and pull-out forces of PMMA-based crowns bonded on a titanium base. Airborne particle abrasion of the crown internal surface and conditioning it with an MMA-based liquid may be recommended to improve retention of titanium base temporary restorations. Yet, for optimal outcomes, conventional temporary abutments might be preferred.- Published
- 2020
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184. Accuracy of Vertical Dimension Augmentation Using Different Digital Methods Compared to a Clinical Situation-A Pilot Study.
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Lee H, Burkhardt F, Fehmer V, and Sailer I
- Subjects
- Jaw Relation Record, Mandible, Pilot Projects, Vertical Dimension, Dental Articulators, Models, Dental
- Abstract
Purpose: To test the accuracies of different methods of digital vertical dimension augmentation (VDA) by comparison with a clinical situation., Materials and Methods: Bite registrations with approximately 5 mm of VDA were made in the incisor regions of 10 subjects (mean VDA 4.5 mm). The conventional maxillary and mandibular stone casts in maximum intercuspation (MICP) and VDA bite registrations were digitized for all subjects using a laboratory scanner (control group). Lateral portraits were taken of all subjects to locate the position of the condylar axis. Four different digital VDA methods were compared to the control group: 100% rotation of the mandible referring to the lateral picture (100RL); 85% rotation and 15% translation referring to the lateral picture (85R15TL); 100% rotation in normal mounting mode of the Trios virtual articulator (100R); and jaw-motion analysis (JMA) equipment. The amount of VDA for each experimental group was compared to the control group. The augmented distances between the central incisors and the second molars were measured using 3D analyzing software. The ratio of the augmented distances between the posterior and anterior regions (P/A ratio) was calculated. One-way analysis of variance and multiple comparisons via least significant difference test were carried out to determine statistical significance., Results: The P/A ratio of each group was as follows: Control = 0.61; 100RL = 0.55; 85R15TL = 0.61; 100R = 0.53; JMA = 0.52. Significant differences were observed for control vs JMA and for 85R15TL vs JMA (P < .05). The addition of translational movement was the primary factor for increasing the accuracy of digital VDA, with the lateral picture being a secondary factor., Conclusion: VDA using a virtual articulator with 100% rotation induces an error when compared to the clinical situation. When a clinician performs digital VDA, the setting of 85% rotation and 15% translation produces results closer to the real clinical condition.
- Published
- 2020
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185. Fracture Resistance of Zirconia Oral Implants In Vitro: A Systematic Review and Meta-Analysis.
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Bethke A, Pieralli S, Kohal RJ, Burkhardt F, von Stein-Lausnitz M, Vach K, and Spies BC
- Abstract
Various protocols are available to preclinically assess the fracture resistance of zirconia oral implants. The objective of the present review was to determine the impact of different treatments (dynamic loading, hydrothermal aging) and implant features (e.g., material, design or manufacturing) on the fracture resistance of zirconia implants. An electronic screening of two databases (MEDLINE/Pubmed, Embase) was performed. Investigations including > 5 screw-shaped implants providing information to calculate the bending moment at the time point of static loading to fracture were considered. Data was extracted and meta-analyses were conducted using multilevel mixed-effects generalized linear models (GLMs). The Šidák method was used to correct for multiple testing. The initial search resulted in 1864 articles, and finally 19 investigations loading 731 zirconia implants to fracture were analyzed. In general, fracture resistance was affected by the implant design (1-piece > 2-piece, p = 0.004), material (alumina-toughened zirconia/ATZ > yttria-stabilized tetragonal zirconia polycrystal/Y-TZP, p = 0.002) and abutment preparation (untouched > modified/grinded, p < 0.001). In case of 2-piece implants, the amount of dynamic loading cycles prior to static loading ( p < 0.001) or anatomical crown supply ( p < 0.001) negatively affected the outcome. No impact was found for hydrothermal aging. Heterogeneous findings of the present review highlight the importance of thoroughly and individually evaluating the fracture resistance of every zirconia implant system prior to market release., Competing Interests: The authors declare no conflict of interest.
- Published
- 2020
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186. Virtual diagnostics and guided tooth preparation for the minimally invasive rehabilitation of a patient with extensive tooth wear: A validation of a digital workflow.
- Author
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Lee H, Fehmer V, Kwon KR, Burkhardt F, Pae A, and Sailer I
- Subjects
- Humans, Tooth Preparation, Vertical Dimension, Workflow, Tooth Attrition, Tooth Wear
- Abstract
The recent evolution of digital technologies in dentistry has enabled virtual 3D diagnostic analysis of a dentition before treatment, allowing for virtual, minimally invasive treatment planning. In this report, an extensively worn dentition was 3D virtual analyzed at an increased vertical dimension of occlusion. Virtual waxing (exocad DentalCAD; Exocad) and subsequent analysis of the need for minimally invasive preparations were performed. Areas of each tooth without adequate clearance for the minimal thickness of a definitive restoration (set at 1.5 mm in the software), including the amount of tooth substance to be removed (GOM Inspect; GOM), were visualized in color. A preparation guide was virtually designed according to this diagnostic plan (3-matic; Materialise) and 3D printed (Connex3 Objet260; Stratasys) from resin (VeroMagenta RGD851; Stratasys). The teeth were minimally prepared using the guide, and the amount of preparation was validated by superimposing the scan of the prepared model on the initial scan and comparing it with the diagnostic plan., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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187. Guided implant surgery for one-piece ceramic implants: a digital workflow.
- Author
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Burkhardt F, Strietzel FP, Bitter K, and Spies BC
- Subjects
- Ceramics, Computer-Aided Design, Denture, Partial, Fixed, Humans, Dental Implants, Workflow
- Abstract
Background: Accurate implant placement in the bone is key to successful implant treatment. Once inserted, it can be difficult to correct the orientation of the implant axis, especially of a one-piece implant. Prosthetic-driven digital implant planning in combination with fully guided implant surgery can offer additional safety in such cases., Case Presentation: The patient presented with a wide, edentulous interdental space extending from sites 13 to 16, which was to be restored with three one-piece zirconia implants supporting a zirconia fixed partial denture comprizing a cantilever to the mesial aspect. Digital planning based on DICOM (Digital Imaging and Communications in Medicine) and intraoral surface data was performed to ensure optimal positioning. Guided implant placement was executed using a contra-angle handpiece with special attachments and a compatible, sleeveless drill guide. Impressions of the implants for the final restoration were acquired using an intraoral scanner. Reflection-related errors were compensated for by using the given digital abutment geometry. The DICOM and STL datasets were superimposed and used as the basis for fabricating a monolithic zirconia restoration through a subtractive milling process. The final restoration was adhesively cemented., Conclusions: By using a prosthetic-driven implant planning strategy, it was possible to place the one-piece ceramic implants without an available implant manufacturer's guide-based solution. This was accomplished using a contra-angle surgical handpiece with special attachments and a compatible drill guide. This approach is particularly recommended for the placement of one-piece implants, which otherwise require irreversible abutment grinding for the adjustment of the implant axis orientation after placement. To increase the precision of the digital impressions of the implants, the ideal abutment geometry was imported and superimposed onto the scan data. The results demonstrate that the proposed method can dispense with the need for gingival retraction when acquiring impressions for implants of this type in the future.
- Published
- 2020
188. Right ventricular function and mechanics in chemotherapy- and radiotherapy-naïve cancer patients.
- Author
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Tadic M, Baudisch A, Haßfeld S, Heinzel F, Cuspidi C, Burkhardt F, Escher F, Attanasio P, Pieske B, and Genger M
- Subjects
- Aged, Echocardiography, Female, Humans, Male, Middle Aged, Neoplasms complications, Retrospective Studies, Ventricular Dysfunction, Right complications, Ventricular Dysfunction, Right diagnostic imaging, Neoplasms physiopathology, Ventricular Dysfunction, Right physiopathology, Ventricular Function, Right physiology
- Abstract
The present research evaluated right ventricular (RV) structure, function and mechanics in the cancer patients before initiation of chemo- or radiotherapy, and the association between cancer and decreased RV longitudinal strain. This retrospective investigation included 101 chemo- and radiotherapy-naïve patients with solid cancer and 38 age- and gender-matched controls with similar cardiovascular risk profile. Echocardiographic examination and strain evaluation was performed in all participants. RV structure and RV systolic and diastolic function estimated with conventional echocardiographic parameters were similar between the cancer patients and controls. However, RV global longitudinal strain (- 22.7 ± 2.6% vs. - 21.1 ± 2.4%, p < 0.001) was significantly decreased in the cancer patients than in controls. The same was revealed for RV free wall endocardial (- 33.6 ± 4.3% vs. - 31.4 ± 4.0%, p = 0.006) and mid-myocardial (- 25.2 ± 3.6% vs. - 23.7 ± 3.8%, p = 0.035) longitudinal RV strains, whereas difference was not found in RV free wall epicardial longitudinal strain. The presence of cancer was independently of age, gender, body mass index, left ventricular hypertrophy, diabetes, hypertension and pulmonary pressure associated with reduced RV global longitudinal strain (OR 3.79; 95% CI 2.18-10.92, p < 0.001), as well as with decreased free wall RV longitudinal strain (OR 5.73; 95% CI 3.17-9.85, p < 0.001). RV strain is deteriorated in the chemo- and radiotherapy-naïve cancer patients. Endocardial and mid-myocardial layers are more affected than epicardial strain in the cancer patients. The presence of cancer is independently of other clinical parameters associated with reduced RV longitudinal strain.
- Published
- 2018
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189. Left Ventricular Strain in Chemotherapy-Naive and Radiotherapy-Naive Patients With Cancer.
- Author
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Tadic M, Genger M, Baudisch A, Kelle S, Cuspidi C, Belyavskiy E, Burkhardt F, Venneri L, Attanasio P, and Pieske B
- Subjects
- Adult, Cardiotoxicity diagnostic imaging, Cardiotoxicity physiopathology, Case-Control Studies, Chemotherapy, Adjuvant, Female, Humans, Logistic Models, Male, Middle Aged, Multivariate Analysis, Neoplasms mortality, Neoplasms pathology, Observer Variation, Prognosis, Radiotherapy, Adjuvant, Reference Values, Retrospective Studies, Risk Assessment, Survival Analysis, Ventricular Dysfunction, Left mortality, Ventricular Function, Left drug effects, Ventricular Function, Left radiation effects, Echocardiography methods, Neoplasms drug therapy, Neoplasms radiotherapy, Ventricular Dysfunction, Left diagnostic imaging, Ventricular Dysfunction, Left etiology
- Abstract
Background: We sought to investigate left ventricular (LV) function and mechanics in patients with cancer before they received chemotherapy or radiotherapy, as well as the relationship between cancer and reduced LV multidirectional strain in the whole study population., Methods: The retrospective study involved 122 chemotherapy- and radiotherapy-naive patients with cancer and 45 age- and sex-matched controls with a cardiovascular risk profile similar to that of the patients with cancer. All the patients underwent echocardiographic examination before introduction of chemotherapy or radiotherapy., Results: LV longitudinal (-19.1% ± 2.1% vs -17.8% ± 3.5%; P = 0.022), circumferential (-22.9% ± 3.5% vs -20.1% ± 4.1%; P < 0.001), and radial (40.5% ± 8.8% vs 35.2% ± 10.7%; P = 0.004) strain was significantly lower in the patients with cancer than in the control group. Endocardial and midmyocardial longitudinal LV strain was significantly reduced in the patients with cancer compared with the controls, whereas epicardial longitudinal strain was similar between these groups. Endocardial, midmyocardial, and epicardial circumferential strain was significantly lower in the chemotherapy- or radiotherapy-naive patients with cancer than in the controls. Cancer was associated with reduced longitudinal (odds ratio [OR], 9.0; 95% confidence interval [CI], 2.20-23.50; P < 0.001), reduced circumferential (OR, 7.1; 95% CI, 3.80-20.40; P < 0.001), and reduced radial strain (OR, 7.2; 95% CI, 3.41-25.10; P < 0.001) independent of age, sex, body mass index, diabetes, and hypertension., Conclusions: LV mechanics was impaired in the patients with cancer compared with the controls even before initiation of chemotherapy and radiotherapy. Cancer and hypertension were associated with reduced LV multidirectional strain independent of other clinical parameters. The present results indicate that cancer itself potentially induces cardiac remodelling independent of chemotherapy and radiotherapy., (Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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190. Right ventricular strain in heart failure: Clinical perspective.
- Author
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Tadic M, Pieske-Kraigher E, Cuspidi C, Morris DA, Burkhardt F, Baudisch A, Haßfeld S, Tschöpe C, and Pieske B
- Subjects
- Biomechanical Phenomena, Echocardiography, Heart Failure diagnostic imaging, Heart Failure mortality, Heart Failure therapy, Heart Ventricles diagnostic imaging, Heart-Assist Devices, Humans, Predictive Value of Tests, Prognosis, Stress, Mechanical, Stroke Volume, Ventricular Dysfunction, Right diagnostic imaging, Ventricular Dysfunction, Right mortality, Ventricular Function, Left, Ventricular Remodeling, Heart Failure physiopathology, Heart Ventricles physiopathology, Myocardial Contraction, Ventricular Dysfunction, Right physiopathology, Ventricular Function, Right
- Abstract
The number of studies demonstrating the importance of right ventricular remodelling in a wide range of cardiovascular diseases has increased in the past two decades. Speckle-tracking imaging provides new variables that give comprehensive information about right ventricular function and mechanics. In this review, we summarize current knowledge of right ventricular mechanics in heart failure with reduced ejection fraction and preserved ejection fraction. We searched PubMed, MEDLINE, Ovid and Embase databases for studies published from January 2000 to December 2016 in the English language using the following keywords: "right ventricle"; "strain"; "speckle tracking"; "heart failure with reduced ejection fraction"; and "heart failure with preserved ejection fraction". Investigations showed that right ventricular dysfunction is associated with higher cardiovascular and overall mortality in patients with heart failure, irrespective of ejection fraction. The number of studies investigating right ventricular strain in patients with heart failure with reduced ejection fraction is constantly increasing, whereas data on right ventricular mechanics in patients with heart failure with preserved ejection fraction are limited. Given the high feasibility, accuracy and clinical implications of right ventricular strain in the population with heart failure, it is of great importance to try to include the evaluation of right ventricular strain as a regular part of each echocardiographic examination in patients with heart failure. However, further investigations are necessary to establish right ventricular strain as a standard variable for decision-making., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)
- Published
- 2017
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191. Predictive and concurrent validity of standardized neurodevelopmental examinations by the Griffiths scales and Bayley scales of infant development II.
- Author
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Chaudhary T, Walch E, Herold B, Metze B, Lejeune A, Burkhardt F, and Bührer C
- Subjects
- Child, Preschool, Developmental Disabilities classification, Developmental Disabilities therapy, Early Intervention, Educational, Female, Follow-Up Studies, Humans, Infant, Infant, Newborn, Infant, Premature, Diseases classification, Infant, Premature, Diseases therapy, Male, Neurologic Examination standards, Psychometrics statistics & numerical data, Reference Values, Reproducibility of Results, Developmental Disabilities diagnosis, Infant, Low Birth Weight, Infant, Premature, Diseases diagnosis, Neurologic Examination statistics & numerical data
- Abstract
Standardized examinations of preterm infants are used to identify candidates for early intervention. We aimed to assess the predictive power and concurrent validity of the mental development index of the Bayley scales of infant development II (Bayley MDI) and the Griffiths scales developmental quotient (Griffiths DQ) in healthy term and preterm infants <1500 g birth weight without major perinatal complications.137 Infants (89 term, 48 preterm) were examined by both tests at a corrected age of 6, 12, and 22 months, and 114 went on to undergo Bayley assessments at 39 months.There were significant correlations between Bayley and Griffiths results at 6, 12, and 22 months (r=0.530, 0.714, and 0.833, respectively, p<0.001) but Bland Altman plots revealed major systematic bias at 6 months (Griffiths>Bayley, mean differences 14.3±9.8) and 22 months (Bayley>Griffiths, mean difference 5.2±13.9) and wide 95% limits of agreement at 6, 12 and 22 months (35.9%, 40.0%, and 52.4%, respectively). The agreement for a presumptive diagnosis of developmental impairment in the group of preterm infants between Bayley examinations obtained at 39 months corrected age (reference) and previous examinations was poor at 6, 12, and 22 months for both Bayley and Griffiths (Cohen's kappa for Griffiths: 0.225, 0.192, 0.369; for Bayley: 0.121, 0.316, 0.369, respectively).Caution should be exercised when interpreting results from standardized neurodevelopmental examinations obtained during the first 2 years of life in comparatively well preterm infants., (© Georg Thieme Verlag KG Stuttgart · New York.)
- Published
- 2013
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192. Gain in chromosome 8q correlates with early progression in hormonal treated prostate cancer.
- Author
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Steiner T, Junker K, Burkhardt F, Braunsdorf A, Janitzky V, and Schubert J
- Subjects
- Aged, Aged, 80 and over, Biomarkers blood, Biopsy, Chromosome Aberrations, Chromosome Deletion, Chromosomes, Human, Pair 18 genetics, Chromosomes, Human, Pair 8 genetics, Disease Progression, Follow-Up Studies, Humans, Male, Middle Aged, Prostate pathology, Prostate-Specific Antigen blood, Prostatic Neoplasms diagnosis, Statistics as Topic, Time Factors, Treatment Outcome, Hormones therapeutic use, Prostatic Neoplasms drug therapy, Prostatic Neoplasms genetics
- Abstract
Objective: Development and especially hormone refractant progression of prostate cancer are incompletely understood. Clinical studies evaluating genetic aberrations of prior therapy biopsies in correlation with progression data in patients receiving hormone therapy for prostate cancer have not been performed until now., Methods: After DNA isolation from histological sections of primary prostate cancer biopsies, comparative genomic hybridization (CGH) was performed according to standard protocols. Primary staging, clinical course and PSA levels of the patients were assessed., Results: CGH was performed on 28 primary prostate cancer samples. After a mean follow-up of 36 months 11 (39%) of the patients showed progression of disease under hormonal treatment. In patients without and with progression we found the following results, respectively: losses of 6q (41/36%), 8p (41/45%), 16q (23/18%), 18q (30/9%), and gains of 8q (12/64%; P < 0.0001) and 17 (47/26%)., Conclusions: Gain of 8q is found predominantly in primary core biopsies of local advanced or metastasized prostate cancers. It shows in univariate analysis significant correlation with progression in hormone treated prostate cancer. This fact suggests that gain in 8q represents a marker of aggressiveness in prostate cancer.
- Published
- 2002
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193. Pantoprazole versus omeprazole: influence on meal-stimulated gastric acid secretion.
- Author
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Dammann HG and Burkhardt F
- Subjects
- 2-Pyridinylmethylsulfinylbenzimidazoles, Adult, Anti-Ulcer Agents adverse effects, Benzimidazoles adverse effects, Cross-Over Studies, Dose-Response Relationship, Drug, Double-Blind Method, Gastric Acidity Determination, Gastric Mucosa physiology, Humans, Male, Omeprazole adverse effects, Pantoprazole, Postprandial Period, Proton Pump Inhibitors, Random Allocation, Sulfoxides adverse effects, Time Factors, Anti-Ulcer Agents pharmacology, Benzimidazoles pharmacology, Gastric Acid metabolism, Gastric Mucosa drug effects, Omeprazole pharmacology, Sulfoxides pharmacology
- Abstract
Aims: To determine the influence of recommended therapeutic doses of pantoprazole and omeprazole on meal-stimulated acid secretion., Methods: In this double-blind, placebo-controlled, three-period crossover study, 12 healthy male volunteers received 40 mg pantoprazole od, 20 mg omeprazole od or placebo at 08:00 h for 5 days in a randomized order. Meal-stimulated acid secretion was determined by means of a homogenized test meal, and intragastric titration on day 1, 4-6 h, 8-10 h, 16-18 h, and 24-26 h, and on days 3 and 5, 4-6 h after oral drug administration., Results: On day 1 (4-6 h after oral drug administration), meal-stimulated acid secretion was decreased by 36% and 24% after administration of 40 mg pantoprazole or 20 mg omeprazole, respectively. After 3 and 5 days of dosing, the decreases were 88% and 85% with 40 mg pantoprazole, and 70% and 74% with 20 mg omeprazole. At all measuring points during the 5-day dosing periods, 40 mg pantoprazole proved superior to 20 mg omeprazole in inhibiting meal-stimulated gastric acid secretion. The differences were statistically significant for pantoprazole on day 1, 24-26 h after oral drug administration and on day 3 (P = 0.0425 and P = 0.0244, respectively). On day 1, only pantoprazole was significantly better than placebo (P = 0.0210, 4-6 h after dosing; P = 0.0093, 8-10 h after dosing and P = 0.0068, 16-18 h after dosing)., Conclusion: Pantoprazole 40 mg is significantly more effective than omeprazole 20 mg in inhibiting meal-stimulated acid secretion. In addition, pantoprazole exhibits a more rapid onset of action.
- Published
- 1999
194. The effects of oral rabeprazole on endocrine and gastric secretory function in healthy volunteers.
- Author
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Dammann HG, Burkhardt F, and Wolf N
- Subjects
- 2-Pyridinylmethylsulfinylbenzimidazoles, Administration, Oral, Adult, Anti-Ulcer Agents administration & dosage, Area Under Curve, Benzimidazoles administration & dosage, Circadian Rhythm, Cross-Over Studies, Double-Blind Method, Endocrine Glands drug effects, Gastric Acid metabolism, Gastric Juice metabolism, Gastric Mucosa drug effects, Hormones blood, Humans, Hydrocortisone blood, Hydrogen-Ion Concentration, Male, Omeprazole analogs & derivatives, Rabeprazole, Reference Values, Testosterone blood, Anti-Ulcer Agents pharmacology, Benzimidazoles pharmacology, Endocrine Glands metabolism, Gastric Mucosa metabolism, Proton Pump Inhibitors
- Abstract
Aim: To evaluate the short-term effects of rabeprazole 20 mg on endocrine parameters, in particular serum testosterone and cortisol, and on 24 h intragastric pH, H+ activity and nocturnal gastric acid secretion., Methods: In this double-blind, two-period crossover study, 12 healthy young male volunteers were randomly given oral rabeprazole 20 mg o.m. or placebo for 14 days. There was a washout period of at least 1 week between the two studies. The effects of rabeprazole and placebo on cortisol and testosterone (primary criteria), and on tri-iodothyronine, thyroxine, 17beta-oestradiol, thyroid-stimulating hormone, thyroxine-binding protein, parathyroid hormone, insulin, glucagon, rennin, aldosterone, follicle-stimulating hormone, luteotrophic hormone, prolactin, somatotrophic hormone, dehydroepiandrosterone, cortisol-binding globulin and urinary 6-beta hydroxycortisol were compared. Intragastric 24 h pH, 24 h H+ activity and nocturnal gastric acid secretion were determined by pH probe and gastric aspiration., Results: Rabeprazole produced no clinically relevant effects on endocrine function as assessed by measurement of serum testosterone, circadian serum cortisol levels, ACTH-stimulated serum cortisol levels and 17 other endocrine function tests. Rabeprazole significantly increased the 24 h median pH values compared to placebo (on Days 7 and 14 median values ranged from 3.92 to 6.88 with rabeprazole and from 1.48 and 4.22 with placebo, P < 0.001) and significantly decreased the integrated 24 h H+ activity (AUC08--08) from 343 mmol/L/h with placebo to 44 mmol/L/h with rabeprazole (P < 0.001). Following cessation of dosing, intragastric pH levels decreased and H+ activity increased, but acid secretion did not recover completely during the next 72 h. The mean value for nocturnal gastric acid secretion on Days 7 and 8 was 36 mmol/6 h with placebo and 5.6 mmol/6 h with rabeprazole (P < 0.001). Rabeprazole was well tolerated., Conclusion: Rabeprazole did not influence endocrine function in healthy young male volunteers during short-term dosing. Rabeprazole substantially increased intragastric pH over a 24 h period and significantly decreased intragastric acidity and nocturnal gastric acid secretion.
- Published
- 1999
- Full Text
- View/download PDF
195. Enteric coating of aspirin significantly decreases gastroduodenal mucosal lesions.
- Author
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Dammann HG, Burkhardt F, and Wolf N
- Subjects
- Adult, Cross-Over Studies, Double-Blind Method, Duodenal Diseases pathology, Female, Gastric Mucosa pathology, Humans, Intestinal Mucosa pathology, Male, Stomach Diseases pathology, Tablets, Enteric-Coated, Anti-Inflammatory Agents, Non-Steroidal administration & dosage, Anti-Inflammatory Agents, Non-Steroidal adverse effects, Aspirin administration & dosage, Aspirin adverse effects, Duodenal Diseases chemically induced, Stomach Diseases chemically induced
- Abstract
Background: Low-dose aspirin (acetylsalicylic acid, ASA) increases the risk of developing peptic ulceration., Aim: To investigate the gastroduodenal mucosal tolerability of enteric-coated ASA (EC-ASA) 100 mg/day compared to either placebo (study 1) or plain ASA 100 mg/day (study 2) in healthy volunteers., Methods: Study 1: In this double-blind study 18 volunteers received randomized dosing with either EC-ASA 100 mg or placebo for 15 days. Study 2: 41 volunteers underwent randomized 7-day dosing of either EC-ASA 100 mg or plain ASA 100 mg in this double-blind, parallel-group, comparison study. In both studies acute gastroduodenal mucosal lesions were assessed endoscopically before treatment, on the morning of day 1 after the first dose (only in study 2), and on the morning after the last dose of the test medication., Results: Study 1 did not reveal any significant differences between the lesion scores of EC-ASA and placebo. In contrast, in study 2 significantly higher total gastroduodenal mucosal lesion scores were observed on day 1 after the first dose and after 7 days of dosing with plain ASA (mean sum of the lesion scores in the gastric fundus, body, antrum and in the duodenal bulb: day 1: plain ASA 3.95+/-3.38 vs. EC-ASA 1.43+/-1.91, P = 0.03; day 7: plain ASA 6.35+/-4.10 vs. EC-ASA 2.00+/-2.02, P = 0.0004). Tolerance of the test drugs was good, and no other adverse events were observed., Conclusions: Enteric-coated aspirin 100 mg/day causes significantly less gastroduodenal damage over 7 days than the same dose of plain aspirin, when given to healthy subjects. There was little gastric injury and no significant differences between EC-ASA and placebo in this respect.
- Published
- 1999
- Full Text
- View/download PDF
196. Lansoprazole versus omeprazole: influence on meal-stimulated gastric acid secretion.
- Author
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Dammann HG, Fuchs W, Richter G, Burkhardt F, Wolf N, and Walter TA
- Subjects
- 2-Pyridinylmethylsulfinylbenzimidazoles, Adult, Depression, Chemical, Dose-Response Relationship, Drug, Enzyme Inhibitors adverse effects, Humans, Lansoprazole, Male, Omeprazole adverse effects, Enzyme Inhibitors pharmacology, Food, Gastric Acid metabolism, Omeprazole analogs & derivatives, Omeprazole pharmacology, Proton Pump Inhibitors
- Abstract
Aims: To investigate, by means of meal-stimulated acid secretion, the extent to which differences in plasma half-life, bioavailability and the recommended therapeutic dose can influence the antisecretory potency of lansoprazole and omeprazole., Methods: In this double-blind, placebo-controlled, crossover study, 10 healthy male volunteers received 15 mg or 30 mg lansoprazole, 20 mg or 40 mg omeprazole or placebo for 5 days, in a randomized order. Meal-stimulated acid secretion was determined by means of a homogenized test meal and intragastric titration., Results: On day 1, meal-stimulated acid secretion was decreased by 35% and 45% after administration of 15 mg or 30 mg lansoprazole, and by 16% and 42% after 20 mg or 40 mg omeprazole. After 3 and 5 days of dosing the decreases were 53% and 48% with 15 mg lansoprazole, 82% and 82% with 30 mg lansoprazole, 43% and 39% with 20 mg omeprazole, and 76% and 83% with 40 mg omeprazole. At all measuring points during the 5-day dosing periods, lansoprazole 15 mg and 30 mg proved superior to 20 mg omeprazole in inhibiting meal-stimulated gastric acid secretion, but the differences were only statistically significant for the lansoprazole 30 mg dose, 30 mg lansoprazole and 40 mg omeprazole proved equipotent. On day 1 only 30 mg lansoprazole was significantly better than placebo., Conclusion: This study demonstrated the following order of antisecretory potency: 30 mg lansoprazole = 40 mg omeprazole > 15 mg lansoprazole approximately 20 mg omeprazole.
- Published
- 1997
- Full Text
- View/download PDF
197. Hepatitis A-vaccines: a comparison between three methods of antigen determination.
- Author
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Burkhardt F, Glück R, Finkel-Jimenez B, and Brantschen S
- Subjects
- Animal Testing Alternatives, Animals, Evaluation Studies as Topic, Hepatitis A Antibodies, Hepatitis A Vaccines, Hepatitis Antibodies blood, Humans, Immunoenzyme Techniques, Mice, Radioimmunoassay methods, Viral Hepatitis Vaccines isolation & purification, Viral Hepatitis Vaccines standards, Antigens, Viral analysis, Hepatitis A Virus, Human immunology, Viral Hepatitis Vaccines immunology
- Published
- 1996
198. Semisynthetic chemical modification of the antifungal lipopeptide echinocandin B (ECB): structure-activity studies of the lipophilic and geometric parameters of polyarylated acyl analogs of ECB.
- Author
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Debono M, Turner WW, LaGrandeur L, Burkhardt FJ, Nissen JS, Nichols KK, Rodriguez MJ, Zweifel MJ, Zeckner DJ, and Gordee RS
- Subjects
- Acylation, Animals, Anti-Bacterial Agents pharmacology, Antifungal Agents pharmacology, Echinocandins, Magnetic Resonance Spectroscopy, Mass Spectrometry, Mice, Mice, Inbred ICR, Microbial Sensitivity Tests, Structure-Activity Relationship, Anti-Bacterial Agents chemistry, Antifungal Agents chemistry, Fungal Proteins, Peptides, Peptides, Cyclic
- Abstract
Echinocandin B (ECB) is a lipopeptide composed of a complex cyclic peptide acylated at the N-terminus by linoleic acid. Enzymatic deacylation of ECB provided the peptide "nucleus" as a biologically inactive substrate from which novel ECB analogs were generated by chemical reacylation at the N-terminus. Varying the acyl group revealed that the structure and physical properties of the side chain, particularly its geometry and lipophilicity, played a pivotal role in determining the antifungal potency properties of the analog. Using CLOGP values to describe and compare the lipophilicities of the side chain fragments, it was shown that values of > 3.5 were required for expression of antifungal activity. Secondly, a linearly rigid geometry of the side chain was the most effective shape in enhancing the antifungal potency. Using these parameters as a guide, a variety of novel ECB analogs were synthesized which included arylacyl groups that incorporated biphenyl, terphenyl, tetraphenyl, and arylethynyl groups. Generally the glucan synthase inhibition by these analogs correlated well with in vitro and in vivo activities and was likewise influenced by the structure of the side chain. These structural variations resulted in enhancement of antifungal activity in both in vitro and in vivo assays. Some of these analogs, including LY303366 (14a), were effective by the oral route of administration.
- Published
- 1995
- Full Text
- View/download PDF
199. [Effective prevention of indomethacin-induced gastroduodenal mucosal lesions with roxatidine acetate].
- Author
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Dammann HG, Wolf N, and Burkhardt F
- Subjects
- Adult, Cross-Over Studies, Humans, Male, Peptic Ulcer chemically induced, Single-Blind Method, Histamine H2 Antagonists therapeutic use, Indomethacin, Peptic Ulcer prevention & control, Piperidines therapeutic use
- Abstract
In this randomized single-blind cross-over study the gastroduodenal damaging effect of indometacin 75 mg bid alone and in combination with roxatidine acetate (CAS 78628-28-1, Roxit) 75 mg nocte or 75 mg bid was evaluated in 12 healthy male volunteers. Prior to the start of the three therapeutic periods subjects underwent endoscopic examination to exclude gastroduodenal mucosa lesions. On days 7 and 14 of therapy 2 h after the application of the last indometacin dose subjects underwent endoscopy again. The 7- and 14-days administration of indometacin 75 mg bid, indometacin 75 mg bid plus roxatidine 75 mg nocte and indometacin 75 mg bid plus roxatidine 75 mg bid led to gastroduodenal mucosa lesion scores of 1.67 +/- 0.40 and 2.00 +/- 0.35, 1.33 +/- 0.28 and 1.50 +/- 0.29, 0.42 +/- 0.23 and 1.00 +/- 0.33 (mean +/- SEM), respectively. These differences were statistically significant when comparing indometacin 75 mg bid versus indometacin 75 mg bid plus roxatidine 75 mg bid (p < 0.004 and < 0.008, respectively). This study shows that roxatidine acetate represents an effective alternative in the prophylaxis of NSAID-induced gastroduodenal mucosa lesions.
- Published
- 1995
200. Effects of pantoprazole on endocrine function in healthy male volunteers.
- Author
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Dammann HG, Bethke T, Burkhardt F, Wolf N, Khalil H, and Luehmann R
- Subjects
- 2-Pyridinylmethylsulfinylbenzimidazoles, Adult, Benzimidazoles adverse effects, Cross-Over Studies, Double-Blind Method, Gastric Juice drug effects, Gastric Mucosa drug effects, Gastric Mucosa metabolism, Humans, Hydrocortisone blood, Hydrogen-Ion Concentration, Male, Omeprazole analogs & derivatives, Pantoprazole, Proton Pump Inhibitors, Secretory Rate drug effects, Sulfoxides adverse effects, Testosterone blood, Benzimidazoles pharmacology, Endocrine Glands drug effects, Sulfoxides pharmacology
- Abstract
Method: In a randomized, double-blind, two-period crossover study, pantoprazole 40 mg or placebo were given orally to 12 male volunteers for 2 weeks each. There was a wash-out period of at least 1 week between the two treatment periods. The effects of pantoprazole or placebo on cortisol and testosterone (primary criteria), and tri-iodothyronine, thyroxine, thyroid-stimulating hormone, thyronine-binding protein, parathyroid hormone, insulin, glucagon, renin, aldosterone, follicle-stimulating hormone, luteotrophic hormone, prolactin and somatotrophic hormone were compared. In addition, intragastric 24-h pH, 24-h H(+)-activity, and volume of nocturnal gastric juice were determined by gastric aspiration technique., Results: Pantoprazole did not influence plasma levels of testosterone, circadian cortisol concentrations or plasma cortisol levels after exogenous adrenocorticotropic hormone stimulation, as compared to placebo (P > 0.05, Koch's test). Furthermore, there were no clinically relevant changes with any of the other endocrine parameters. Pantoprazole significantly increased the median 24-h pH (group median 4.3 vs. 1.8; P < 0.001) and decreased 24-h H(+)-activity (4.0 vs. 22.6 mmol/L; P < 0.001). The volume of nocturnal gastric juice did not significantly differ between the two treatments. Pantoprazole was well tolerated and the frequency of adverse events was similar to placebo. No drug-related changes in laboratory values were observed., Conclusion: Pantoprazole did not influence endocrine function in healthy male volunteers during short-term treatment.
- Published
- 1994
- Full Text
- View/download PDF
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