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Several protocols have been used with computer-aided design and computer-aided manufacture (CAD-CAM) prostheses after image-guided implant surgery based on a prosthetically driven surgical plan. For delayed approaches, a CAD-CAM custom healing abutment can be manufactured before the surgery and installed immediately after implant placement. However, information on the use of emergence profile segmentation on which to base the digital design and on the use of low-cost 3-dimensional printers to produce custom healing abutments are lacking. The purpose of this article was to present a fully digital workflow to digitally design and 3-dimensionally print custom healing abutments with a biocompatible light-polymerizing resin based on the natural emergence profile of the tooth to be replaced.

There is controversy in the literature regarding clinical outcomes of CAD/CAM laminate veneers. The aim of the present study was to assess the impact of different levels of CAD expertise and different software programs on the reliability and reproducibility of digital wax patterns of laminate veneers and single crowns.The present preliminary in vitro study was performed on 10 prepared maxillary central incisors available in dental study models. Of the total, five central incisors were prepared with shoulder finish lines for single crowns, whereas the other five underwent incisal shoulder preparation for laminate veneers. The models were scanned using an intraoral scanner. Four dentists (group DENT) and four CAD dental technicians (group CAD) with expertise in different software programs performed digital diagnostic waxing on all prepared teeth. The resulting digital wax patterns (n = 80) were exported as standard tessellation language (STL) files and superimposed on gold standard digital wax patterns (obtained from the original shape of the teeth before preparations). 3D mesh deviations at the cervical margins as well as distal, mesial, and incisal/palatal surfaces between each STL and the gold standard digital wax patterns were calculated in millimeters using a CAD software program. The mean time required by each operator to perform digital waxing was also recorded. Paired comparisons between groups DENT and CAD as well as between nondental and dental software programs were performed for the crowns and laminate veneers using the Wilcoxon signed-rank and paired t tests (α = 0.05).For group DENT, median deviations for single crowns were 0.15 mm (range: 0.08 to 1.05 mm) and for laminate veneers they were 0.15 mm (range: 0.08 to 0.76 mm). For group CAD, median deviations for single crowns were 0.16 mm (range: 0.09 to 0.73 mm) and for laminate veneers they were 0.10 mm (range: 0.06 to 0.53 mm). The Wilcoxon signed-rank test revealed a statistically significant difference between groups DENT and CAD (P = 0.041) and between the software programs (P = 0.029) for laminate veneers, but not for single crowns (P0.05). Furthermore, mean times required for group CAD and for dental software programs were significantly shorter than those for group DENT (P = 0.001) and for nondental software programs (P = 0.001), respectively.Within the limitations of the present study, the findings suggest that CAD expertise and the software program significantly affect digital wax patterns for laminate veneers, but not for single crowns. (Int J Comput Dent 2022;25(4):361-0; doi: 10.3290/j.ijcd.b3555819).

Purpose: The aim of this in vitro study was to assess the role of bandwidth on the area of magnetic resonance imaging (MRI) artifacts caused by orthodontic appliances composed of different alloys, using different pulse sequences in 1.5 T and 3.0 T magnetic fields. Materials and methods: Different phantoms containing orthodontic brackets (ceramic, ceramic bracket with a stainless-steel slot, and stainless steel) were immersed in agar gel and imaged in 1.5 T and 3.0 T MRI scanners. Pairs of gradient-echo (GE), spin-echo (SE), and ultrashort echo time (UTE) pulse sequences were used differing in bandwidth only. The area of artifacts from orthodontic devices was automatically estimated from pixel value thresholds within a region of interest (ROI). Mean values for similar pulse sequences differing in bandwidth were compared at 1.5 T and 3.0 T using analysis of variance. Results: The comparison of groups revealed a significant inverse association between bandwidth values and artifact areas of the stainless-steel bracket and the self-ligating ceramic bracket with a stainless-steel slot (P, peer-reviewed

This article presents a rapid technique for the accurate transfer of implant positions immediately after image-guided surgery to enable the immediate installation of a definitive complete-arch implant-supported prosthesis with an implant biological width of 3 mm within 3 appointments. A sleeveless copy of the implant surgical guide is magnetically connected to a reference guide to ensure the accurate capture of cylindrical titanium transfer abutments. In the laboratory, the sleeveless guide with the splinted transfer abutments attached is used to generate a definitive cast to be scanned with a desktop scanner. The resulting digital definitive cast is then combined with the original meshes of the prosthetically driven virtual treatment plan to enable a definitive computer-aided design and computer-aided manufactured prosthesis to be fabricated and installed with passive fit.

BACKGROUND Little is known on the effect of varying implant diameters, especially with mini implants (ie, less than 3 mm in diameter), on oral health-related quality of life (OHrQoL). PURPOSE To compare OHrQoL and satisfaction in patients with mandibular overdentures immediately retained by either two conventional or two mini-implants. MATERIALS AND METHODS Edentulous patients receiving immediately loaded overdentures retained by Locators on either two conventional diameter (4.1 mm) or two mini (2.9 mm or less) implants were selected based on available buccal-lingual ridge width in the intraforaminal area. Two questionnaires were used (Oral Health Impact Profile-14 [OHIP-14]; and Denture Satisfaction Questionnaire [DSQ]) to determine OHrQoL and overall denture satisfaction. Questionnaires were filled out at six different time points up to a 1-year follow-up. Mann-Whitney U test was used for group comparisons. Friedman and Wilcoxon tests were used to identify changes within group along the time points. Correlation between OHIP-14 and DSQ was assessed with Spearman test. RESULTS A total of 48 patients were analyzed and equally distributed to each group. The conventional group presented a significantly smaller change of OHIP functional score from the baseline to the first week of follow-up after surgery (P = .017). In addition, total DSQ scores were significantly higher for the conventional group at 12 weeks (P = .022) and there was a significant difference between groups in satisfaction with mandibular prosthesis at 24 weeks (P = .034). Correlation between OHIP-14 and DSQ was not significant (P > .05). Individual results of each group (ie, within group analysis) over all assessed time points revealed a significant OHrQoL (P = .001 for conventional, P = .006 for mini-implants) and satisfaction (P < .001 for both groups) improvement in both groups. CONCLUSION Mandibular overdentures retained by two conventional or mini-implants lead to a significant and comparable improvements in OHrQoL and satisfaction over a 1-year follow-up.

A technique using a digital workflow for performing crown lengthening by using a free software program is presented to digitally design a single surgical guide. The technique consists of obtaining standard tessellation language (STL) files from intraoral scans from a digital design of the new tooth shape and from a cone beam computed tomography (CBCT) scan, after which Digital Imaging and Communications in Medicine (DICOM) files are converted to the STL format. These files are then superimposed and used for surgical planning of the crown-lengthening procedure. The main component of the surgical guide is a labial upper band representing the biological width measurement based on the predicted digitally designed future gingival margin position. Accordingly, the lower edge of the band indicates the level of the main marginal incision, whereas the top of the band indicates the level where the alveolar bone crest must be repositioned by alveolotomy during the surgical crown-lengthening procedure. By performing an adequate diagnosis of the potential restorative outcome, the new position of the gingival margin and the crown shape can be predicted, and whether osteoplasty is needed can be determined.

The full digital workflow involves the combination of intraoral and cone beam computerized tomography scans. In the present case report, a second intraoral scan is performed after soft tissue management facilitated by the use of a 3-dimensional-printed interim implant restoration. The new STL file resulting from the second intraoral scan can be associated with the previous STL from the initial intraoral scan. The custom abutment was also digitally designed as an STL file, and no implant scan bodies were required for intraoral scanning.

Background Little is known about differences between mini-implants and conventional immediately loaded implants for overdentures. Objectives To compare clinical outcomes using two immediately loaded conventional or mini-implants for mandibular overdentures. Materials and methods Edentulous patients receiving either conventional (4.1 mm) or mini-implants (2.9 mm or less), based on available bone width were analyzed. All implants were immediately loaded with mandibular overdentures installed using locator attachments. Digital periapical radiographs for measuring marginal bone loss and clinical outcomes (ie, periodontal probing, plaque, and bleeding indices) were assessed at 1, 3, 6, and 12-month follow-up periods. Results Fifty patients (25 receiving conventional implants-12 females, mean age of 65.3 ± 7.3 years; and 25 receiving mini-implants-11 females, mean age of 66.8 ± 8.1 years) was analyzed. Peak insertion torque (P = .001) and bone loss (P = .02), as well as change in plaque (P = .02) and bleeding (P = .04) indices at 12 months differed significantly between groups. Furthermore, linear regression revealed the height of the locator as a risk factor for bone loss (P = .038). Conclusions The present findings suggest that two mini-implants are significantly more susceptible to bone loss after immediate loading, for which the height of locator might be considered a risk factor.

The present technique report describes a digital workflow for flapless implant surgery after onlay block bone graft healing in the esthetic area. Virtual removal of block fixation screws and optimal single-tooth implant position and digital crown waxing were planned from cone beam computed tomography (CBCT) and intraoral scans. Two different surgical guides were digitally designed and 3D-printed to allow for flapless implant surgery. The first surgical guide was used to remove all 3 fixation screws from a healed onlay block graft, whereas the second guide was used to determine the implant position and direction. The present methodology may be considered a time-efficient flapless approach for placing implants in sites with block grafts.

Background The risk of femoral neck fracture progressively increases with age. However, the reasons behind this consistent increase in the fracture risk can't be completely justified by the decrease in the bone mineral density. The objective of this study was to analyze the correlation between various bone structural features and age. Study Design & Methods A total of 29 consecutive patients who suffered an intracapsular hip fracture and underwent joint replacement surgery between May 2012 and March 2013 were included in this study. A 2 cm × 1 cm O cylindrical trabecular bone sample was collected from the femoral heads and preserved in formaldehyde. Bone mineral density (BMD), microarchitecture, organic content and crystallography were analyzed using a Dual-energy X-ray absorptiometry scan, micro-CT scan, and high resolution magic-angle-spinning-nuclear magnetic resonance (MAS-NMR), respectively. Statistical correlations were made using Spearman´s or Pearson´s correlation tests depending on the distribution of the continuous variables. Results The mean patient age was 79.83 ± 9.31 years. A moderate negative correlation was observed between age and the hydrogen content in bone (1H), which is an indirect estimate to quantify the organic matrix (r = −0.512, p = 0.005). No correlations were observed between BMD, trabecular number, trabecular thickness, phosphorous content, apatite crystal size, and age (r = 0.06, p = 0.755; r = −0.008, p = 0.967; r = −0.046, p = 0.812; r = −0.152, p = 0.430, respectively). A weak positive correlation was observed between Charlson´s comorbidity index (CCI) and c-axis of the hydroxiapatite (HA) crystals (r = −0.400, p = 0.035). Conclusion The femoral head relative protein content progressively decreases with age. BMD was not correlated with other structural bone parameters and age. Patients with higher comorbidity scores had larger HA crystals. The present results suggest that the progressive increase in the hip fracture risk in elderly patients could be partially explained by the lower bone protein content in this age group.

The use of hyaluronic acid (HA) fillers in lip augmentation represents today 1 of the most widely used nonsurgical aesthetic procedures in the world. Regarding the severe complications are rare, insufficient professional experience for recognizing signs of vascular impairment and inadequate technique could lead to severe lip skin necrosis complications. Several of existing treatment protocols in the literature to treat vascular complication are mainly based on the use of hyaluronidase. Nevertheless, there is no consensus on dosage, interval between doses and complementary protocol among the aforementioned studies. This case aims to present a conservative approach for the clinical management of serious vasculature complications with HA injection. A high dose of hyaluronidase(11500 IU) with additional multimodal treatment was performed to the upper lip, nasolabial fold, and nose that successfully reversed a vascular complication process. The present findings suggest that the use of high doses of hyaluronidase with the complementary protocol used herein might be a promising approach in the treatment of severe vascular complication in the lips caused by HA filling.

Objectives: The aim of this study was to evaluate bone mineral adipose tissue (BMAT) volume in 21 alveolar bone specimens, as determined by 14 T MRI, and correlate them to the radiodensity values obtained pre-operatively of regions of interest (ROIs) by cone beam computed tomography (CBCT), and to the bone-volume-to-tissue-volume ratio values obtained by micro-CT, the gold-standard for morphometric data collection. Methods: Partially edentulous patients were submitted to a CBCT scan, and the radiographic bone densities in each ROI were automatically calculated using coDiagnostiX software. Based on the CBCT surgical planning, a CAD/CAM stereolithographic surgical guide was fabricated to retrieve a bone biopsy from the same ROIs scanned preoperatively, and then to orientate the subsequent implant placement. The alveolar bone biopsies were then collected and scanned using the micro-CT and 14 T MRI techniques. Pearson’s correlation test was performed to correlate the results obtained using the three different techniques. Results: In the 21 eligible bone specimens (6 females, 15 males), age (mean age 52.9 years), micro-CT, and 14 T MRI variables were found to be normally distributed (p > 0.05). The strongest—and only statistically significant (p < 0.05)—correlation was found between micro-CT and 14 T MRI values (r = 0.943), and the weakest, between 14 T MRI and CBCT values (r =–0.068). Conclusions: The findings suggest that 14 T MRI can be used to evaluate BMAT as an indirect marker for bone volume, and that CBCT is not a reliable technique to provide accurate bone density values., peer-reviewed

Nose augmentation with Hyaluronic acid (HA) fillers has been considered the preferred technique for minimally invasive cosmetic procedures. Despite severe complications related to HA injection are rare, none of the existing treatment protocols has been established as standard. The aim of this report is to present an alternative approach to treat nasal skin necrosis related to HA injection. A high dose of hyaluronidase - 6000 IU was applied in the nose, for the purpose of reversing a necrotic process. The present findings suggest that a high dose of hyaluronidase could be a promising approach to treat severe nasal skin necrosis caused by HA filler.

Purpose The purpose of this study was to investigate the impact of radiotherapy on mandibular bone tissue in head and neck cancer patients through an analysis of pixel intensity and fractal dimension values on digital panoramic radiographs. Materials and methods Thirty patients with radiographic records from before and after 3-dimensional (3D) conformational radiotherapy were selected. A single examiner carried out digital analyses of pixel intensity values and fractal dimensions, with the areas of interest unilaterally located in the right angle medullary region of the mandible below the mandibular canal and posterior to the molar region. Results Statistically significant decreases were observed in the mean pixel intensity (P=0.0368) and fractal dimension (P=0.0495) values after radiotherapy. Conclusion The results suggest that 3D conformational radiotherapy for head and neck cancer negatively affected the trabecular microarchitecture and mandibular bone mass.

Purpose This histologic study aimed at assessing bone healing after treatment with simvastatin in association with low-level laser therapy (LLLT). Methods Twenty-four male rats (Wistar) were submitted to surgery to create a bone defect of 5 mm in diameter in the parietal bone. These rats were randomly and equally divided into four treatment groups (n = 6): control (C), in which no treatment was performed; simvastatin (SIM), in which rats received daily subcutaneous doses of 2.5 mg/kg of simvastatin; LLLT, which was daily applied to the bone defect; and SIM-LLLT, in which both SIM and LLLT were daily applied. All laser irradiations were carried out with a 830-nm infrared diode laser (GaAlAs) with maximum output of 100 mW and a dose of 4 J, totaling 16 J per session. Rats were euthanized on the 12th postoperative day. Formalin-fixed paraffin-embedded bone samples were obtained and stained with hematoxylin-eosin (HE) and toluidine blue for optical microscope analysis. Degree of inflammation, new vascular formation, tissue repair, and osteoblastic activity were assessed. Results Categorical analysis of the histologic slides revealed newly formed bone reaching the center of the surgical wound in two animals from the SIM group, two from the LLLT group, and three from the SIM-LLLT group. Greater new bone formation and a lower degree of inflammation were observed in the animals that had bone neoformation at the center of the defect, especially in the LLLT and SIM-LLLT groups. SIM and C groups presented greater angiogenesis than LLLT and SIM-LLLT. SIMLLLT therapy showed a statistically significant reduction in the degree of inflammation when compared to the control group (P Conclusion Within the limitations of this study, the present results suggest that a combination of simvastatin and low-level laser therapy may stimulate better bone formation.

Objectives The aim of this study was to compare the efficacy of conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in correctly identifying the presence of disease in the major salivary glands and correctly distinguish sialadenitis from pleomorphic adenoma. Study Design Twenty-one patients diagnosed with unilateral sialadenitis or pleomorphic adenoma were selected. The nonaffected contralateral glands were also analyzed. T1- and T2-weighted MRI and DWI were obtained using spin-echo pulse sequences with a 1.5 Tesla MRI device. The diagnostic performance of 3 observers was evaluated for detection of salivary gland alterations and differentiation between sialadenitis and pleomorphic adenoma based on evaluation of MRI in comparison with DWI. Results Intra-and interobserver reliability ranged from 0.86 to 0.94. DWI demonstrated greater sensitivity and accuracy values compared with MRI for both detection of disease and differentiation of sialadenitis from pleomorphic adenoma, with specificity values that were greater than or equal to those of MRI. DWI yielded significantly higher diagnostic odds ratios compared with MRI for both identification of disease and differentiation between lesions. Conclusions DWI demonstrated better diagnostic performance in the detection of alterations in the salivary glands and in differentiating between sialadenitis and pleomorphic adenoma compared with conventional T1 and T2-weighted MRI.

Marginal bone loss around immediately placed implants may compromise esthetic outcomes in the anterior maxilla. The relatively recent socket-shield technique of partial extraction therapy has been described as being useful to maintain the structure of peri-implant tissues. The present technique report introduced a digital workflow to perform image-guided implant placement after partial extraction therapy. In this technique, digital 3-dimensional images are used to plan and orient the flapless surgical procedure and to digitally design a custom abutment based on the natural emergence profile as segmented from the tooth to be extracted.

Inadequate craniofacial orientation of computed tomography (CT) scans can have significant implications in all three planes of space. The purpose of this study was to present the reproducibility of a 3-dimensional skeletal-based method of craniofacial orientation for virtual surgical planning. The protocol was defined by landmarks commonly used for cephalometry, and required identification of basion, nasion, right porion, and right orbitale, and navigation in all CT views (coronal, sagittal, and axial) for correction of yaw, roll, and pitch. Reproducibility of the method was assessed using eight CT scans that were randomly selected and anonymised. The observer group consisted of six oral and maxillofacial surgeons with varying levels of experience (resident or faculty) who performed craniofacial orientation according to the proposed method. Results were expected to be below 2° of variation, when overall accuracy as well as the influence of the academic level of the observers and symmetry of the evaluated anatomy, were considered as independent variables. Overall accuracy for all cases and for yaw, roll, and pitch were always below 2° of variation, without influence of level of experience and symmetry. Interobserver assessment was categorised as excellent in all instances, and intraobserver evaluation demonstrated consistency in the orientation of all axes. The proposed craniofacial orientation protocol presented in this study is easy to learn, applicable to computer-aided surgical planning, and can be performed by the non-technical clinician, resulting in excellent reproducibility and consistency.

Purpose To compare the marginal fit and internal surface roughness of CAD/CAM zirconia copings milled with 3- and 5-axis milling devices. Materials and methods Forty titanium implant stock abutments (4.8 mm in diameter, 4 mm in height) screwed to dental implants (4.1 mm in diameter) embedded in resin were considered phantoms and included in this in vitro study. All 40 phantoms were scanned with the same intraoral scanner, from which images of the virtual wax-up of zirconia copings were obtained and exported as standard tessellation language (STL) files. From each resulting STL file, two copings were milled: one using a 3-axis milling device, and the other using a 5-axis milling device. After milling, zirconia copings underwent high-speed sintering before being analyzed for marginal fit (ie, marginal gap measurement), and internal surface roughness was assessed with a scanning electron microscope (SEM). Statistical comparisons between groups were assessed with Mann-Whitney test. Results Median marginal gap values were 34.80 μm (95% CI: 0.00 to 173.98) for the 5-axis milling device group and 141.97 μm (95% CI: 82.13 to 163.46) for the 3-axis milling device group. A statistically significant difference in marginal gap was found between both milling device groups (P = .039). In addition, qualitative SEM analysis indicated higher internal surface roughness for the 3-axis milling device group. Conclusion Within the limitations of this study, the present findings suggest that 5-axis milling devices outperform 3-axis milling devices for milling CAD/CAM zirconia copings from intraoral scans of implant stock abutments.

Radiographic interpretation and diagnosis of dental anomalies may impose challenge to the dental clinician and this could largely be attributed to the limitations of the conventional two-dimensional (2D) imaging modalities. Dental anomalies, which can occur due to pathologic or developmental factors, can be assessed and diagnosed more accurately using cone beam computed tomography (CBCT) three-dimensional (3D) imaging. 3D visualization can aid the clinician with evaluating the extent of the dental anomaly and its relation to the adjacent anatomic structures. The advent of CBCT as contemporary diagnostic aid may lead to a paradigm shift in the diagnosis and management of dental anomalies.

The temporomandibular joint (TMJ) is among the most important anatomical structures to be diagnosed in three-dimensional (3D) images. Despite the lack of scientific evidences on correlations between orthodontic treatments and temporomandibular disorders (TMD), the latter should be properly diagnosed, treated, and followed up during orthodontic treatment planning and execution. In this context, TMD diagnosis requires detailed clinical and imaging examinations from adequate methods such as conventional radiographs, medical computed tomography (CT), cone beam CT (CBCT), magnetic resonance imaging (MRI), and ultrasonography. Because of the anatomic complexity of the TMJ, 3D multiplanar reconstructions may be required in many cases to provide volumetric imaging analyses. For this purpose, bone alterations may be better visualized with CT and CBCT, whereas soft tissue alterations may require MRI scans, which are also useful to diagnose articular disc displacement and morphological alterations.

OBJECTIVE: To compare the influence of coronavirus disease 2019 (COVID-19) pandemic on the student reported outcomes among dental students reading/studying different courses offered in the only dental school in Malta. MATERIALS AND METHODS: An anonymous questionnaire consisting of 13 closed-ended and open-ended questions was sent to all students (n = 97) at the Faculty of Dental Surgery at the University of Malta. Emergent themes from open-ended questions were identified and tallied. Since data were classified as categorical ranks, nonparametric tests were used to compare variables among the different courses, years of study, preclinical/clinical students, and gender categories. RESULTS: Dental technology students were significantly less stressed about contracting COVID-19 (P = 0.005) and regarding lack of preparation due to inability to physically go to the library (P = 0.019). Female students reported significantly more anxiety for the following factors: "feeling anxious all the time" (P = 0.033), "worried about contracting COVID-19'" (P = 0.012), "worried that a family member may contract COVID-19'" (P = 0.048), "more anxious about exams this year because of the challenges we are facing" (P = 0.029), and "concern about losing manual dexterity skills" (P = 0.038). Qualitative data gathered show considerable stress reported by students regarding changes in examination processes and formats and lack of timely communication. CONCLUSION: Students were greatly affected by the COVID-19 pandemic and this caused fear of losing their manual dexterity skills, anxiety related to its consequences on their long-term plans, and anxiety related to the examinations. Dental schools in turn should adapt rapidly and customize changes that are specific to the individual student cohort and their stage of training.

Studies performed in the medical area have shown that an indirect diagnosis of bone mineral density (BMD) is feasible by assessing the amount of bone marrow fat with non-ionizing magnetic resonance imaging (MRI). In dentistry, radiographic methods are still the most used for alveolar bone diagnosis. The present literature review aimed at addressing the role of MRI in assessing BMD in medicine and dentistry. MEDLINE and EMBASE databases were searched for articles published up to 2019. A total of 428 potentially eligible papers were screened. Of these, 397 were excluded after title, abstract and keyword assessment, yielding 31 papers that potentially met the inclusion criteria. Eleven studies were then excluded because their full texts did not discuss the role of MRI in the indirect diagnosis of BMD. As a result, a total of 20 studies were finally identified as eligible for inclusion in this literature review. Most studies found satisfactory accuracy of MRI for indirectly assessing BMD by quantifying bone mineral fat (BMF). However, only one of these studies was on dentistry. Within the limitations of this study, the present findings suggest that MRI is accurate to indirectly estimate bone density by assessing BMF, and could be clinically relevant during dental treatment planning.

The aim of this report is to present a digital workflow technique to design a customized abutment for provisionalization of an immediate-placed implant based on the natural emergence profile of the tooth to be extracted. The workflow involves the combination of intraoral and CBCT scans, from which three-dimensional (3D) reconstructions of soft tissue and alveolar bone, as well as of the tooth to be extracted are obtained and exported as STL files. The files are imported to a computer-aided design (CAD) software, in which a virtual wax-up and custom abutment design are performed considering the natural emergence profile of the patient’s tooth prior to extraction. Since the customized abutment is digitally designed, it can also be used as a scan body, to be directly scanned intraorally after soft tissue healing around an interim implant restoration. The custom abutment digitally designed can be then produced by milling zirconia with an optimally chosen color, in accordance with the aesthetic needs of the patient.

Background Fractures in mandibular implant-retained overdentures are a common complication. However, little is known on the related risk factors and outcome differences when using two conventional diameter or two mini implants. Purpose The purpose of this study was first, to evaluate the required maintenance and complications with the overdentures and second, to analyze risk factors for overdenture fractures. Materials and methods This cohort study was conducted in edentulous patients with complete dentures. Patients received either two conventional (4.1 mm in diameter) and two mini (2.9 mm or less in diameter) implants, based on available buccal-lingual ridge width. All implants were immediately loaded with mandibular overdentures retained by Locator abutments. The number of prosthodontic after care visits (scheduled and unscheduled) were recorded and compared between the two implant diameter groups. Fracture occurrence was the primary outcome variable. Risk estimates were presented as odds ratios (ORs) with 95% confidence intervals (CIs). The ORs were adjusted for potential clinical confounders (ie, necessity of relining, matrix recapture, abutment loosening, implant diameter, height of the Locator, and retention force). Results A total of 50 edentulous patients were analyzed. One conventional diameter and three mini implants failed within a 1-year follow-up period. Prosthetic maintenance requirements for overdentures on both implant diameter groups were comparable. A total of 12 overdenture fractures (four in the mini implant group and eight in the conventional diameter group) occurred. Adjusted OR (AOR) analysis showed a significant association between abutment loosening and overdenture fracture (AOR = 12.00, 95% CI = 1.11-129.45; P = .041). Conclusion Within the limitations of this study, the present findings suggest that implant diameter does not affect number of prosthetic maintenance and complications, and that abutment loosening is a risk factor for overdenture fractures, regardless of the implant diameter used.

In light of the COVID-19 pandemic a global shortage of personal protective equipment (PPE) made necessary the development of techniques to rapidly design and adapt filtering masks for local manufacturing using 3D printed methods to help protect healthcare workers. Several Standard Tessellation Language (STL) files of 3D-printed masks have become available in the internet and some models have got approval from regulatory organisations such as the Food and Drug Administration (FDA). This technical report aimed at describing a straightforward methodology for custom-fitting 3D-printed filtering masks to 3D face scans using free software. This article presents modifications of an open-source add-on program (My Face Mask, Wasp, Massa Lombarda, Italy) developed for a free computer aided-design (CAD) software (Blender 2.82, Amsterdam, Netherlands) to design a 3D-printed face mask with polylactic acid (PLA) filament, for P3 filters (99.95% filtration of airborne particles) from face scan STL files. Preliminary results demonstrated that a dental clinician was able to digitally design and 3D-print a mask that provided satisfactory comfort and adaptation. The use of online application for a face scan and an open source software can be used to custom fit a 3D-printed mask to on individuals face.

To describe a method of digitally customizing 3D-printed face mask designs using 3D face scans and free software.The procedure of creating customized face masks initially involved importing and aligning STL files of face scans and mask components in free CAD software. The imported mask described in this article is composed of three different STL files (body, filter structure, and grid). The body of the mask was then edited to fit precisely into the face scan STL by using the software's offset tool, followed by adjustments and smoothening of the surfaces of the edges. The resulting customized body of the mask plus the filter and grid STL files were exported and 3D printed with polylactic acid (PLA) filament using a fused deposition modeling (FDM) 3D printer. For the purposes of comparison, a conventional 3D-printed mask (from the original STL files, without being customized for the face scan) was also 3D printed from the original STL files. Both face masks were tested on the same two volunteers.The customized 3D-printed face mask presented a higher adaptation compared with the conventional face mask. The area of facial contact matched the one digitally designed in the software. The 3D-printed grid could clip exactly into the filter, which in turn could be precisely screwed into the body of the face mask.Within the limitations of this technical report, the present findings suggest that customized 3D-printed face masks with enhanced adaptation can be digitally designed using face scans and free CAD software.

Statement of problem The digital waxing of single crowns can be affected by the quality of intraoral scans and use of computer-aided design (CAD) software programs. However, clinical outcomes of the resulting crowns are also affected by computer-aided manufacturing (CAM) methodologies. Studies on the effect of different levels of expertise on digital waxing are lacking. Purpose The purpose of this in vitro study was to assess the impact of different levels of expertise on the reliability and reproducibility of margin outlining during digital waxing. Material and methods Thirty analogs of implant stock abutments (O4.8×4 mm) were embedded into resin blocks. To simulate different clinical situations, abutments were divided into 3 groups: 10 abutments (group GOS) received artificial gingiva and were scanned with an open system intraoral scanner, while 10 abutments with (group GIS) and 10 abutments without artificial gingiva (group IS) were scanned with an intraoral scanner within an integrated CAD-CAM system. All resulting standard tessellation language (STL) files were used by 2 different observers (an experienced CAD professional and a clinician with basic CAD knowledge) to digitally design a left mandibular central incisor in the same software program. All resulting digital crown designs were exported to STL files to assess crown margin accuracy at the coupling interface by superimposition with the control STL file of the scan body designed for the same abutment by the manufacturer. For this purpose, a CAD software program was used to automatically calculate median, minimum, and maximum deviations of margins in millimeters. Statistically significant pairwise differences among groups and between observers were assessed with the Wilcoxon signed-rank test (α=.05). Results For the CAD professional, median deviations between designed crown STL files and the control STL of the scan body were 0.08 mm (range: 0.04 to 0.15) for group GOS; 0.10 mm (range: 0.06 to 0.18) for group GIS; and 0.05 mm (range: 0.03 to 0.08) for group IS. For the clinician, median deviations were 0.08 mm (range: 0.04 to 0.12) for group GOS; 0.11 mm (range: 0.07 to 0.17) for group GIS; and 0.05 mm (range: 0.04 to 0.11) for group IS. There were no significant differences between observers (P>.05). However, statistically significant differences were found between group IS and the other 2 groups (P=.001) but not between groups GOS and GIS (P>.05). Conclusions The present findings suggest that a digital wax pattern made with a dental CAD software program is not affected by varying levels of expertise but might be affected by subgingival margins.

PURPOSE Pixel values from cone-beam computed tomography (CBCT) are proportional to bone density. This study aimed to correlate and compare pixel values of healed maxillary sinus grafts and adjacent native bone (NB). MATERIAL AND METHODS This study was conducted on CBCT scan patients referred for maxillary sinus floor augmentation with biphasic calcium phosphate (n = 31). Graft height and width measurements were performed. In addition, mean pixel values were calculated in 3 different regions: NB, sinus graft close to NB (CNB), and sinus graft far from NB (FNB). Micro-CT and histological analyses of bone specimens of a representative case were also performed. RESULTS Significant correlations were found between CNB and graft height (r = 0.41; P < 0.021); and FNB and graft width (r = 0.519, P < 0.003). In addition, pixel values from both graft groups (CNB and FNB) differed significantly (P < 0.001). Finally, histological sections revealed smaller areas with newly formed bone in the FNB area. CONCLUSIONS Within the limitations of this study, the present findings suggest that pixel values of sinus grafted areas are directly correlated with the extension of the grafted area.

Purpose: This study aimed to carry out a systematic review of studies in the literature comparing conventional imaging techniques with cone-beam computed tomography in terms of the role of these techniques for assessing any of the following periodontal conditions and parameters: infrabony defects, furcation involvement, height of the alveolar bone crest, and the periodontal ligament space., Materials and methods: Interventional and observational studies comparing conventional imaging techniques with cone-beam computed tomography were considered eligible for inclusion. The MEDLINE and Embase databases were searched for articles published through 2017. The PRISMA statement was followed during data assessment and extraction., Results: The search strategy yielded 351 publications. An initial screening of the publications was performed using abstracts and key words, and after the application of exclusion criteria, 13 studies were finally identified as eligible for review., Conclusion: These studies revealed cone-beam computed tomography to be the best imaging technique to assess infrabony defects, furcation lesions, the height of the alveolar bone crest, and the periodontal ligament space., peer-reviewed

Purpose The search for optimizing rehabilitation results with the use of osseointegrated implants has led oral surgeons to look for other technologies that can provide better predictability for treatments; however, effectiveness must be considered as well. This study aimed to compare temperature variation during preparation of implant surgical beds using conventional rotary implant burs versus ultrasonic tips and to study perforation effectiveness by analyzing the functional wear of both systems and the influence of such wear on the overheating of cortical bone. Materials and methods This evaluation was made using thermocouples placed in fresh bovine cortical bone (femur) and connected to a data collector so that the recorded temperatures could provide the thermal behavior of both systems after repeated use of the burs and piezoelectric tips, to compare the wear and the loss of cutting efficiency. Scanning electron microscopy (SEM) was used to compare the topography of both systems' perforations. Biostatistics assays were performed comparing both techniques as well. Results The collected data and images showed that the wear of the burs and tips did not significantly influence the temperature variation, and the greatest variation occurred in the piezoelectric system for preparations of 13-mm depth. The SEM images show a different surface topography between both systems. While the burs cut the bone, showing a smooth surface, the piezoelectric tips condense the bone and present a rough surface. Conclusion The use of either rotatory burs or piezoelectric tips generates a temperature that does not affect the tissue healing. Burs create a smooth surface, and piezoelectric tips show a more rough and condensed bone surface. The wear of both systems does not have a relevant increase in temperature after the preparation of 30 surgical beds.

Adenoid cystic carcinoma (ACC) is a slowly growing malignant neoplasm with a propensity for perineural invasion. Microscopic invasion of ACC often prevents its detection on computed tomography (CT) or magnetic resonance imaging (MRI). We herein report a rare case of sublingual ACC presenting as a "skip lesion" that rapidly infiltrated the mandible after tumor resection. A 64-year-old man presented to Okayama University Hospital with an 18-month history of swelling in the right floor of the mouth. Clinical examination displayed an ulcerated swollen mass in that region. An enhanced mass was detected in the right sublingual space on CT and MRI. Bone surface erosion was observed at the inferior border of the mandible, but continuity with the sublingual mass or mass around that lesion was not detected by imaging. Sublingual tumor resection and selective neck dissection were performed by the pull-through method. Histopathologically, the surgical margins were free of cancer cells, and the tumor was diagnosed as ACC. Continuity with the sublingual mass and mandibular bone was not detected intraoperatively. However, marked bone resorption was detected in the anterior mandible 3 months after the operation. Biopsy was performed, and the findings indicated the same histological type of sublingual ACC. This case suggests that a malignant tumor close to the jaw bone requires the clinician to consider the possibility of bone invasion and to observe a wide region surrounding the tumor using imaging examination.

Purpose: To determine the effectiveness of cone beam computed tomography (CBCT) images obtained with different kilovoltage settings compared with intraoral periapical photostimulable storage phosphor (PSP) plate images in the detection of chemically created peri-implant defects utilizing a bovine rib bone model in vitro. Materials and Methods: After placing 80 implants in bovine ribs, peri-implant circumferential bone defects of different sizes were created with 70% perchloric acid. CBCT images (3D Accuitomo 170) were acquired at 90 and 75 kVp, and intraoral periapical images were acquired using a PSP system (Carestream KODAK, CS 7600). Using a 5-point Likert scale, two oral and maxillofacial radiologists (OMR) and two oral and maxillofacial surgeons (OMS) evaluated the likelihood of a bone defect being absent or present. The kappa statistic was used to compare observer agreement, and area under the curve values were compared using analysis of variance and the post hoc Tukey test. Significance was set at P ≤ .05. Results: PSP reliability ranged from discordance to slight for small defects and fair to moderate for larger defects. For CBCT, OMRs had good agreement for defects using 90 kVp, and slight to fair using 75 kVp. Agreement for OMS observations was fair for 75 kVp, and varied from slight to good for 90 kVp. Small lesions were detected more effectively by CBCT than by PSP, and larger lesions were detected more effectively by CBCT at 90 kVp than by CBCT at 75 kVp or by PSP. Conclusion: CBCT imaging at 90 kVp was associated with a significantly higher rate of detection of both small and large chemically simulated bone defects than PSP or CBCT at 75 kVp. CBCT imaging at 75 kVp proved better than PSP for the detection of small defects.

This technique report describes a fully digital workflow in which two surgical guides (i.e. one for alveolar bone reduction and the other for implant placement) are magnetically connected to ensure stability during full-arch implant surgery following guided bone reduction. Digital prosthesis design as well as virtual bone reduction and implant planning are developed from the superimposition of facial, intraoral and CBCT scans. With this technique, different surgical guides and interim poly(methylmethacrylate) (PMMA) fixed prosthesis are precisely connected with magnets after being digitally designed and 3D-printed. As a result, such magnetic connection allows for satisfactory stability of the implant surgical guide, as well as of the interim fixed PMMA fixed prosthesis during capture of screw-retained abutments.

Background Bone strength depends on multiple factors such as bone density, architecture and composition turnover. However, the role these factors play in osteoporotic fractures is not well understood. Purpose The aim of this study was to analyze trabecular bone architecture, and its crystal and organic composition in humans, by comparing samples taken from patients who had a hip fracture (HF) and individuals with hip osteoarthritis (HOA). Methods The study included 31 HF patients and 42 cases of HOA who underwent joint replacement surgery between 1/1/2013 and 31/12/2013. Trabecular bone samples were collected from the femoral heads and analyzed using a dual-energy X-ray absorptiometry, micro-CT, and solid-state high-resolution magic-angle-spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. Results No differences in proton or phosphorus concentration were found between the two groups using 1H single pulse, 31P single pulse, 31P single pulse with proton decoupling NMR spectroscopy, in hydroxyapatite (HA) c-axis or a-axis crystal length. Bone volume fraction (BV/TV), trabecular number (Tb.N), and bone mineral density (BMD) were higher in the HO group than in the HF group [28.6% ± 10.5 vs 20.3% ± 6.6 (p = 0.026); 2.58 mm−1 ± 1.57 vs 1.5 mm−1 ± 0.79 (p = 0.005); and 0.39 g/cm2 ± 0.10 vs. 0.28 g/cm2 ± 0.05 (p = 0.002), respectively]. The trabecular separation (Tp.Sp) was lower in the HO group 0.42 mm ± 0.23 compared with the HF group 0.58 mm ± 0.27 (p = 0.036). In the HO group, BMD was correlated with BV/TV (r = 0.704, p < 0.001), BMC (r = 0.853, p < 0.001), Tb.N (r = 0.653, p < 0.001), Tb.Sp (−0.561, p < 0.001) and 1H concentration (−0.580, p < 0.001) in the HO group. BMD was not correlated with BV/TV, Tb.Sp, Tb.Th, Tb.N, Tb.PF, 1H concentration or HA crystal size in the HF group. Conclusions Patients with HO who did not sustain previous hip fractures had a higher femoral head BMD, BV/TV, and Tb.N than HF patients. In HO patients, BMD was positively correlated with the BV/TV and Tb.N and negatively correlated with the femoral head organic content and trabecular separation. Interestingly, these correlations were not found in HF patients with relatively lower bone densities. Therefore, osteoporotic patients with similar low bone densities could have significant microstructural differences. No differences were found between the two groups at a HA crystal level. Scopus

Purpose: This study compared 2 cone-beam computed tomography (CBCT) systems in the detection of mechanically simulated peri-implant buccal bone defects in dry human mandibles. Materials and methods: Twenty-four implants were placed in 7 dry human mandibles. Peri-implant bone defects were created in the buccal plates of 16 implants using spherical burs. All mandibles were scanned using 2 CBCT systems with their commonly used acquisition protocols: i-CAT Gendex CB-500 (Imaging Sciences, Hatfield, PA, USA; field of view [FOV], 8 cm×8 cm; voxel size, 0.125 mm; 120 kVp; 5 mA; 23 s) and Orthopantomograph OP300 (Intrumentarium, Tuusula, Finland; FOV, 6 cm×8 cm; voxel size, 0.085 mm; 90 kVp; 6.3 mA; 13 s). Two oral and maxillofacial radiologists assessed the CBCT images for the presence of a defect and measured the depth of the bone defects. Diagnostic performance was compared in terms of the area under the curve (AUC), accuracy, sensitivity, specificity, and intraclass correlation coefficient. Results: High intraobserver and interobserver agreement was found (P, peer-reviewed

Purpose: Little is known regarding the accuracy of clinical magnetic resonance imaging (MRI) protocols with acceptable scan times in sinus graft assessment. The aim of this study was to evaluate the correlations between MRI and cone-beam computed tomographic (CBCT) measurements of maxillary sinus grafts using 2 different clinical MRI imaging protocols. Materials and methods: A total of 15 patients who underwent unilateral sinus lift surgery with biphasic calcium phosphate were included in this study. CBCT, T1-weighted MRI, and T2-weighted MRI scans were taken 6 months after sinus lift surgery. Linear measurements of the maximum height and buccolingual width in coronal images, as well as the maximum anteroposterior depth in sagittal images, were performed by 2 trained observers using CBCT and MRI Digital Imaging and Communication in Medicine files. Microcomputed tomography (micro-CT) was also performed to confirm the presence of bone tissue in the grafted area. Correlations between MRI and CBCT measurements were assessed with the Pearson test. Results: Significant correlations between CBCT and MRI were found for sinus graft height (T1-weighted, r=0.711 and P, peer-reviewed

Despite the advent of stereolithography in craniofacial surgery for creating surgical guides and custom synthetic scaffolds, little is known about the feasibility of computer-aided design/computer-aided manufacturing (CAD/CAM) milling of freeze-dried allogeneic bone blocks following previously designed volumetric graft plans. The aim of this technical report is to present a methodology for CAD/CAM milling to achieve the volume and shape of allogeneic bone blocks as estimated by using a virtual planning software. To perform the current methodology, an ex vivo simulation was performed. The milled allogeneic block presented satisfactory dimensional accuracy as compared with the respective three-dimensional virtual model.

A main drawback of bone block graft surgery is the resorption occurring in early stages of healing. To our knowledge, there are no studies comparing outcomes of freeze-dried bone allograft (FDBA) blocks with different architecture.The aim of this work was to investigate different factors that can affect graft resorption and to compare the resorption rates of two different types of allogeneic blocks, corticocancellous and cancellous.A randomized clinical trial was designed. Twenty-eight patients referred for onlay bone augmentation prior to implant placement were included in the study. Preoperative computerized tomography (CT) was taken for all patients. Patients received FDBA blocks of either cancellous or corticocancellous bone obtained from the iliac crest. After a 4-month follow-up, postoperative CT was taken. Then, another surgery was performed, with the purpose to place dental implants. The aforementioned groups were compared for bone resorption and implant outcome using analysis of covariance (ANCOVA) and repeated ANOVA measures, respectively. Demographic data, trabecular bone density, and graft sites were also analyzed.A total of 93 implants were placed in the augmented bone sites over 28 patients. A 100% survival rate was achieved during a mean follow-up period of 24 months in both groups. Higher bone resorption rate was found with cancellous bone grafts (29.2% ± 2.6) compared with corticocancellous grafts (19.3% ± 2.3). Moreover, higher resorption rates in patients with lower bone density (185 Hounsfield Units) (31.7% ± 3.1) and smokers (26.39% ± 2.3) were observed when compared with patients with higher bone density (185 Hounsfield Units) (16.8% ± 2.1) and nonsmokers (22.1% ± 2.3), respectively.Within the limitations of this study, these findings indicate that both corticocancellous and cancellous FDBA grafts constitute a clinical acceptable alternative for bone reconstruction, although cancellous grafts present higher resorption rates. Moreover, host factors such as patient's low bone density and smoking habits may also increase graft resorption rates.