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PURPOSE To investigate the discoloration and surface properties of four CAD/CAM composite resins provoked by a variety of food solutions and cigarette smoke. MATERIALS AND METHODS A total of 74 specimens (N = 370) were prepared per material (Brilliant Crios [Coltene], CeraSmart [GC], Lava Ultimate [3M Espe], Shofu Block HC [Shofu], and SonicFill 2 [Kerr]). Discoloration (ΔE) was investigated with a spectrophotometer. Measurements were taken before immersion in the storage media for 2 weeks (carrot juice, curry, cigarette smoke, red wine, energy drink, and distilled water), immediately after immersion, and after manual polishing of the specimens following immersion. The mean surface roughness (Ra) was measured using a profilometer. Qualitative surface observation was performed with scanning electron microscopy (SEM). Data were analyzed using Kolmogorov-Smirnov, Mann-Whitney U, and one-way analysis of variance with Tukey post hoc tests. RESULTS The highest influence on ΔE after immersion was observed by the storage medium (ηP. = 0.878, P < .001), followed by the interaction between storage medium and material (ηP. = 0.770, P < .001) and the material (ηP. = 0.306, P < .001). For ΔE after polishing, the highest influence was indicated by the interaction of material and medium (ηP. = 0.554, P < .001), followed by the medium (ηP. = 0.244, P < .001) and the material (ηP. = 0.196, P < .001). Immersion in carrot juice led to the highest color change (ΔE: 8.0 to 10.4), whereas the lowest values were recorded in distilled water (ΔE: 2.0 to 2.4). Carrot juice and the energy drink provoked the highest Ra values (0.120 to 0.355 μm). SEM pictures indicated a loss of the organic matrix after manual polishing. CONCLUSION The different materials reacted dissimilarly in the various storage media in terms of discoloration. Surface roughness increased after immersion and polishing. Neither discoloration nor surface roughness could be reset to default by manual polishing.

Background: Preparation exercises represent an essential part in the study of dentistry. Digital grading software can be used for evaluation of prepared artificial teeth, which is mainly based on limited number of teeth and raters. In order to improve a standardized evaluation of preparations, the aim of this study was to assess the inter-rater reliability of a high number of teeth by different raters and, to evaluate specific preparation features. Methods: Therefore, a total of 1465 preparations of an artificial lower molar were evaluated with grades from 1 to 5 by four dentists out of three dental schools, and inter-rater reliability was calculated. A specific analysis program was used for objective evaluation of the preparation. Data were analyzed using the Kolmogorov-Smirnov test, Pearson chi-square test, and reliability analysis with a level of significance of p= 0.05. Results: The median value of all grades was 2.75 (IQR: 1.35). Lowest grade variance of 0.00 within the raters’ evaluations was observed in grade group 1. Grade variance of evaluations with grades 1 and 2 differed significantly from all the other grade groups (p≤0.003). The inter-rater reliability factor of all grade groups together was 0.958. Conclusion: Inter-rater reliability was very high, which indicates very good correlation of the given grades. The objective evaluation of preparation features has worsened with ascending grade groups. Significant differences within the grade groups indicate higher agreement when evaluating good preparations. The objective feature convergence and preparation angle, marginal width, and stump height have a crucial impact on evaluation.

Objectives A variety of dental materials are available for the fabrication of telescopic crowns. The aim was to investigate the impact of material combinations and removal and insertion cycles on their retention forces. Materials and methods CAD/CAM-fabricated cobalt–chromium–molybdenum (CoCr) and zirconia (ZrO2) primary crowns were combined with polyetheretherketone (PEEK), polyetherketoneketone (PEKK), CoCr, and ZrO2 secondary crowns (four combinations included PEEK/PEKK secondary crowns in a thickness of 0.5 mm bonded to the CoCr tertiary construction), resulting in 12 different material combinations: CoCr–PEEK; CoCr–PEKK; CoCr–ZrO2; CoCr–CoCr; CoCr–PEEK 0.5; CoCr–PEKK 0.5; ZrO2–PEEK; ZrO2–PEKK; ZrO2–ZrO2, ZrO2–CoCr; ZrO2–PEEK 0.5; and ZrO2–PEKK 0.5 (n = 15 pairings per material combination). Pull-off tests were performed with a universal testing machine initially and after 500, 5000, and 10,000 removal and insertion cycles in a mastication simulator. Descriptive statistics with the Kolmogorov–Smirnov, Kruskal–Wallis, and Mann–Whitney U tests were computed (α = 0.05). Results The tested parameters, material combination, and removal and insertion cycles had significant impact on the retention force values (p < 0.001). An increase in removal and insertion cycles was associated with a decrease in retention forces within CoCr and ZrO2 secondary crowns, regardless of the primary crown material. In contrast, PEEK and PEKK secondary crowns presented higher retention load values after 10,000 cycles than initially. Conclusion Different material combinations behaved differently after simulated removal and insertion regimens. This difference should be considered during treatment planning. Clinical relevance Telescopic crown systems should be made of materials with predictable retention forces that do not deteriorate with time. The implementation of new materials and technologies facilitates reproducibility and time-saving fabrication.

Die Einfuhrung der Adhasivtechnik in Kombination mit zahnfarbenen Restaurationsmaterialien zahlt zu den grosten Errungenschaften der restaurativen Zahnheilkunde. Dazu haben adhasiv befestigte Veneers auf der Basis verschiedener silikatkeramischer Materialien ganz wesentlich beigetragen. Sie haben sich zu einer ernsthaften Behandlungsalternative zu klassischen, weitaus invasiveren Restaurationsformen entwickelt. Der Beitrag beschreibt anhand klinischer Beispiele die Prinzipien der modernen Veneertechnik unter besonderer Berucksichtigung der Zusammenarbeit mit dem Zahntechniker bei der Analyse, der Definition des Behandlungsziels, der Farbbestimmung, der Entscheidung zugunsten einer passenden Keramik, der Praparationsgestaltung und der Festlegung des Befestigungsmaterials fur die adhasive Eingliederung. Auserdem wird auf der Basis der vorhandenen wissenschaftlichen Literatur das Langzeitverhalten keramischer Veneers bewertet.

Purpose To investigate the impact of high-speed sintering on the accuracy (trueness and reproducibility) and fit of 4Y-TZP full-coverage single-unit fixed dental prostheses (FDPs) and three-unit FDPs. Materials and methods Single-unit FDPs, conventional three-unit FDPs, and cantilever three-unit FDPs (N = 108; n = 12 per subgroup) were fabricated from: (1) high-speed sintered (1,580°C, about 20 minutes) multi-layer 4Y-TZP (Zolid RS, Amann Girrbach; ZMLH group), as well as two conventionally sintered (1,450°C, about 10 hours) materials: (2) multi-layer 4Y-TZP (Zolid Gen-X, Amann Girrbach; ZMLC group) and (3) monochrome 4Y-TZP (Ceramill Zolid HT+ PS, Amann Girrbach; ZMOC group). All specimens were scanned. Trueness, reproducibility, and fit were measured with 3D analysis software. For data analysis, Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests were performed (α = .05). Results Three-unit FDPs made from ZMLH presented a deterioration of accuracy in comparison to ZMLC (P ≤ .001 to .008). The influence of highspeed sintering on marginal and general fit was not clinically relevant (P = .154 to .877). Conclusion High-speed sintering influenced the accuracy of 4Y-TZP full-coverage single-unit and three-unit FDPs. However, no clinically relevant impact on fit was observed.

Objectives The influence of different cleaning methods, air-abrasion parameters, and aging on shear bond strength (SBS) and tensile bond strength (TBS) of 3D resin luted to composite resin. Materials and methods Nine hundred resin substrates were 3D printed (D20II, Rapid Shape) and cleaned with either isopropanol (ISO), butyldiglycol-based solution (BUT), or centrifugation (CEN). After 24-h storage in 37 °C water, specimens were air-abraded (mean particle size 50 µm; n = 60) with either alumina at 0.1 MPa (AL0.1) or 0.4 MPa (AL0.4) and glass pearls at 0.1 MPa (GP0.1) and 0.4 MPa (GP0.4) or conditioned with visio.link (control) and luted with PanaviaV5. Initially (24 h, 37 °C water storage) or after aging (10,000 thermal cycles), SBS and TBS were measured, and fracture types were examined. Surface free energy (SFE) and roughness (Ra) were determined after air-abrasion. Kolmogorov–Smirnov, Kruskal–Wallis H, Mann–Whitney U, chi-square, and partial eta-squared were computed. Results SBS measurements presented higher values than TBS (p p p p Conclusions Pretreatment with AL0.4 and the control group mainly presented the highest bond strength values. Thermocycling had a positive effect on the bond strength. Clinical relevance According to this study, 3D-printed restorations should be pretreated with AL0.4 or with visio.link before adhesive luting, regardless of their cleaning.

To report the long-term clinical survival and failure rates of single-tooth restorations made of pressable lithium disilicate ceramics (LSTwenty-one patients (12 female, nine male) were treated with 436 minimally invasive single-tooth restorations made of 274 pressed LSThe 274 LSPressed LSDespite the limitations of the clinical observations, single-tooth restorations of both materials can be recommended for permanent use in patients with severe tooth wear.

Extended reality as an additional digital learning concept comprises virtual reality (VR), augmented reality, and mixed reality. In particular, VR allows an interaction in the virtual world. The aim of this study was to evaluate the students' attitude toward a mobile VR application for teaching tooth morphologies.Eighty-two first year dental students were enrolled. After using the VR learning environment with mobile VR glasses at home for 1 week, the students were asked to fill in a questionnaire with 21 questions regarding intuitive handling, and supplemental learning information in comparison to the use of conventional textbooks. Nine questions provided predefined answer options, another nine had the form of a visual analog scale (VAS, range 0%-highly negative to 100%-highly positive), and three allowed free text answers. The data were checked for normal distribution (Kolmogorov-Smirnov test) and was analyzed descriptively.Forty-four percent of the students rated their perception of understanding of dental morphologies much better with VR than with conventional learning. The potential of the VR learning environment for further dental topics was assessed with a median VAS score of 75.8%. Its intuitive handling was evaluated with a median VAS score of 67.1%. The haptic, visual, and auditory supplemental learning information was consistently rated positively with VAS scores of 73.9%, 80.0%, and 71.6%, respectively. Overall, a majority of the students (85.5%) recommended the VR learning environment for dental morphology.The VR dental learning environment allows dental students an additional learning opportunity of dental morphologies, recommended by more than 85% of students.

To investigate the degree of conversion (DC), Martens hardness (HM), elastic indentation modulus (EIT), and flexural strength (FS) of veneering resin composites (SR Nexco Paste (NP), Ceramage Incisal (CI), Gradia Plus (GP); n=60/group) cured with different polymerization devices (bre.Lux Power Unit, Labolight DUO, Otoflash G171, LC-3DPrint Box, PCU LED; n=12/subgroup) after storage. Otoflash G171 and Labolight DUO showed increased DC/HM/EIT. CI presented the lowest DC and highest HM/EIT. NP showed the highest DC and lowest HM/EIT. Within Otoflash G171, Laboligth DUO and PCU LED, highest FS was observed for CI. Storage did not affect DC/HM/EIT for specimens cured with Otoflash G171 or Labolight DUO. With storage not showing an influence on the tested parameters for polymerization devices that otherwise presented superior results, increased storage time cannot be recommended. For the tested resin composites, this study observed a high/low degree of conversion to coincide with respectively low/high amounts of fillers/mechanical properties.

AIM To introduce virtual reality (VR) into the endodontic curriculum for teaching root canal anatomy and to evaluate the effectiveness of this new method on third-year undergraduate students. METHODOLOGY Extracted human teeth were digitized using a CBCT scan and converted into STL files. The corresponding files were either 3D printed or imported into a VR software program. Subsequently, forty-two third-year undergraduate dental students in preclinical training were asked to respond to a questionnaire analysing their ability to detect all the anatomic features of the replica teeth and their comprehension of the underlying root canal anatomy. The investigation was based on three different methods: two-dimensional radiography, CBCT scanning and VR simulation. Data were analysed using McNemar's and binomial test, and the level of significance was set to 0.05 (P = 0.05). RESULTS Students reported that CBCT and VR allowed them to detect all anatomic features more than radiography (P

Objectives To analyze the oral health-related impact profile in patients treated with three different types of dental prosthesis in student courses. Materials and Methods This prospective bicenter clinical trial was conducted with 151 patients being treated with fixed (n = 70), removable (n = 61), or telescopic dental prostheses (n = 20) in clinical student courses of two German universities from October 2018 to October 2019. All patients completed three standardized German versions of the Oral Health Impact Profile (OHIP-G49/53) before prosthetic treatment (T0), at control after 1 week (T1), and after 3 months (T2), divided into five dimensions: (a) appearance, (b) oral function, (c) psychosocial impact, (d) linguistic limitations, and (e) orofacial pain. Data were analyzed with Kolmogorov–Smirnov, Wilcoxon signed-rank, Kruskal–Wallis, Mann–Whitney, and Cronbach’s alpha tests. Results Within T0–T1 and T0–T2, greater improvements were determined for removable compared with fixed dental prostheses for the dimensions’ oral function (p ≤ 0.014), linguistic limitations (p ≤ 0.016), and appearance (p ≤ 0.003). No significant differences were found between fixed and telescopic dental prostheses (p ≥ 0.104) or between removable (partial dental prosthesis with clasps and complete dental prosthesis) and telescopic dental prostheses (p ≥ 0.100). Within T1–T2, a significant improvement in orofacial pain could be determined (p = 0.007). Conclusions Restorations presented an improvement in oral health-related quality of life. Removable dental prostheses showed better improvement than fixed ones in various dimensions. Clinical relevance Knowledge about the influence of oral health-related quality of life on the three different types of prosthesis used in student courses can be of decisive help in dental consultations.

ZusammenfassungSowohl für die Befestigung von Brackets als auch von Aligner-Attachments stehen verschiedene Materialien und Strategien zur Auswahl. Die Vorbereitung der Schmelz-Oberfläche für die adhäsive Befestigung kann mit Phosphorsäure im Etch and Rinse-Verfahren oder mittels diverser selbstätzender Adhäsive vorgenommen werden. Die Materialien zur Befestigung unterscheiden sich hinsichtlich der Monomermatrix, der Füllkörper und deren Anteile sowie ihres Initiatiorsystems. Brackets können direkt oder indirekt adhäsiv befestigt werden. Attachments für die Behandlung mit Alignern können ein- oder zweiphasig auf die entsprechenden Zähne aufgebracht werden. Ziel dieses Artikels ist es, anhand der aktuellen Literatur einen Überblick über die verschiedenen Materialien und Befestigungsstrategien zu geben.

Objectives To test and compare five pressable lithium-X-silicate-ceramics on their mechanical and wear properties. Methods Specimens were pressed and prepared from: i. Amber Press (AP), ii. Celtra Press (CP), iii. Initial LiSi Press (IL), iv. Livento Press (LP), and v. IPS e.max Press (IE). Four-point flexural strength (FS), SEVNB fracture toughness (KIC), three-body wear (3BW), Martens hardness (HM) and indentation modulus (EIT) were measured. For CP, FS and HM were measured with and without additional Power Firing. Each subgroup contained 15 specimens. Data were analyzed using Kolmogorov–Smirnov, one-way ANOVA followed by Scheffe test, Kruskal–Wallis-H-, Mann–Whitney-U-, and Spearman–Rho-test (p Results AP and CP presented higher FS than IL. LP presented the highest Weibull modulus. CP showed lower KIC values than AP, and AP was not significant compared to LP and IE. The most 3BW material loss was observed for CP. CP revealed higher HM values than the remaining ceramics. IL presented lower EIT compared to AP and CP. The following correlations were observed between the test parameters: 3BW with FS (r = 0.279, p = 0.015), with HM (r = −0.378, p = 0.001), and with EIT (r = −0.344, p = 0.004); EIT with FS (r = 0.203, p = 0.028); and HM with FT (r = −0.223, p = 0.027) and EIT (r = 0.884, p Significance AP followed by LP showed the highest and IL followed by CP the lowest properties tested. Power Firing of CP improved the flexural strength. Ceramics with high flexural strength and Martens parameters showed lower wear. Materials with high Martens hardness presented lower fracture toughness values and ones with high indentation modulus showed high flexural strength.

To determine the fracture load before and after artificial aging of implant-supported 4-unit cantilever fixed dental prostheses (FDP) with frameworks made of two differently filled polyetheretherketone (PEEK) compounds and veneered using three different techniques.A total of 120 duplicate 4-unit FDP frameworks were produced (n = 60 milled from PEEK, 20% TiOVeneering technique and filler content significantly affected the fracture load (p 0.001). Prefabricated veneers showed higher fracture load (p ≤ 0.001) whereas digital and conventional veneerings were similar (p = 0.451). PEEK with 30% filler content presented higher fracture load (p 0.001) compared with PEEK with 20%. Aging showed no effect on fracture load (p = 0.176). Regarding fracture types, no significant differences were found among the groups (p = 0.055).Filler content of PEEK compound as well as veneering technique influenced fracture load while aging had no effect on fracture load. FDPs made of PEEK with 30% of filler content veneered using prefabricated veneers had the highest fracture resistance.

To analyze the clinical performance of two-wing retained resin-bonded fixed dental prostheses (RBFDPs) after 5 years of clinical use with respect to technical and biologic complications as well as survival and success rates.RBFDPs were either made of 3Y-TZP zirconia layered by hand (LAVA frame veneered with LAVA Ceram; 3M) or made of metal frameworks (Remanium Star, Dentaurum; layered with Reflex, Wieland). The primary endpoints were de-bonding or fracture. The secondary endpoints marginal integrity, marginal discoloration, abrasion of antagonist dentition, patient satisfaction, Gingival Index (Loe and Silness), and side effects were evaluated at baseline and after 5 years. The survival and success rates were calculated using the Kaplan-Meier method. Log-rank test was used to compare the survival and success rates of the different materials.The mean observation time was 6 years and 10 months. The estimated cumulative ratio of success after 5 years was 88.9% ± 10% for metal-supported and 33% ± 16% for all-ceramic two-wing-retained RBFDPs. After conversion into one-wing retained RDFDPs, the survival was 100% in both groups. Debonding of one of the two wings was the major complication. One zirconia framework fracture occurred. Metal-based two-wing-retained RBFDPs showed a significantly higher success rate, but lower esthetic evaluation.Due to the reduction of technical complication rate and less invasiveness, one-wing-retained RBFDPs should be preferred over two-wing retained RBFDPs whenever possible.

PURPOSE To investigate the tensile bond strength between zirconia abutments and titanium bases, luted with two different resin composite cements, after different cleaning procedures. MATERIALS AND METHODS Zirconia abutments and titanium bases were luted with either a DMA/HEMA-based cement (n = 80; Multilink Hybrid Abutment, Ivoclar Vivadent) or a Bis-GMA/TEGDMA-based cement (n = 80; Panavia V5, Kuraray Noritake). The adhesive gap of half of the specimens was polished (n = 40 per resin composite cement). Four separate specimens underwent roughness measurements and scanning electron microscopy. The specimens were divided into four groups (n = 10 per subgroup): (1) not cleaned, (2) cleaning in an ultrasonic bath, (3) cleaning in an autoclave, and (4) treatment with low-pressure plasma. The specimens were thermocycled (20,000×, 5°C/55°C), tensile bond strength was tested, and fracture types were analyzed. Data were examined using the Kolmogorov-Smirnov test, univariate ANOVA with additional partial eta-squared (ηp2), and the Mann-Whitney U test. The defined level of significance was adjusted by Bonferroni correction (P < .003). RESULTS The tensile bond strength of specimens luted with the DMA/HEMA-based cement was higher than that of specimens luted with the Bis-GMA/TEGDMA-based cement. The polishing step and the cleaning procedures showed no impact on tensile bond strength results. Specimens luted with the DMA/HEMA-based cement presented more cohesive fractures, whereas specimens luted with the Bis-GMA/TEGDMA-based cement presented themselves with more fractures of the interface between the resin composite cement and zirconia abutment. Ra values showed a decline in roughness after polishing for both resin composite cements. CONCLUSION As the DMA/HEMA-based cement showed higher tensile bond strength values, the usage of this resin composite cement for luting implant abutments to titanium bases can be recommended. Neither polishing nor the use of different cleaning procedures had an impact on tensile bond strength.

Background: The Covid-19 pandemic resulted in significant restrictions on dental teaching. The aim of this investigation was to evaluate the attitudes of faculty members towards digital teaching formats and the effort creating digital lectures. Methods: All German dental faculties were invited from January to April 2021 to the online survey by an anonymous voluntary questionnaire. The questionnaire consisted of 27 questions that could be answered with a visual analog scale, free text answers or with fixed answer options. Data was analyzed using the Kolmogorov-Smirnov test and an exploratory data analysis (α=0.05).Results: Before the pandemic, 24.8% of the participating lecturers were using digital teaching and 64.4% had no previous experience. After the outbreak of the pandemic, more than 80% of the lecturers stated that they offer online lectures (86.1%), online seminars (81.2%), and/or online bedside teaching (33.7%). 88.1% see face-to-face teaching as the preferred teaching format.The lecturers also see the greatest opportunities for interaction in the area of analog teaching and significantly worse in synchronous and asynchronous digital teaching. In the course of the pandemic, respondents' attitudes towards online teaching improved in the median of 24.0 to a median of 50.0. Conclusions: Faculty members have positively changed their attitudes towards online teaching formats over the course of the pandemic. Although they see the greatest learning success in conventional face-to-face teaching formats and the creation of digital lectures is associated with a higher effort, they want more online lessons in the future.

High-speed sintering allows the rapid fabrication of esthetic restorations with adequate flexural strength. However, data on the fatigue behavior of high-speed sintered 4 mol% yttria-stabilized tetragonal zirconia polycrystal (4Y-TZP) are lacking.The purpose of this in vitro study was to examine the effect of high-speed sintering and the preshading of blanks (monochrome versus multilayer) on the fatigue behavior of 4Y-TZP ceramics.Four-point flexural strength specimens (N=405) were fabricated from high-speed sintered multilayer 4Y-TZP (Zolid DRS) processed at 1580 °C for about 20 minutes and conventionally sintered at 1450 °C for about 10 hours, multilayer 4Y-TZP (Zolid Gen-x), and monochrome 4Y-TZP (Ceramill Zolid HT+PS), the control group. The specimens were loaded under 5 different dynamic test conditions for fatigue testing (P1-P5). Three were step-stress protocols (P1: 50 N for 5000 cycles; P2: 10 N for 1000 cycles, P3: 5% for 5000 cycles), 1 was tested with a constant force of 720 N (P4), and 1 was tested for different constant load levels (P5). For analysis of P1-P3, the Kaplan-Meier test and Mantel Cox test were performed (α=.05). P4 was analyzed with the Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests, and P5 by creating a load-cycle diagram. A fracture analysis was performed.ZMLC showed better fatigue behavior than ZMLH (P≤.006) and ZMOC (P≤.002) in all 3 step-stress protocols (P1-P3). ZMLH showed results comparable with those for ZMOC (P≥.285). In P4 and P5, all materials showed comparable values (P=.163 for P4).The multilayer technique showed a positive effect on the fatigue behavior of 4Y-TZP. In contrast, high-speed sintering negatively influenced the fatigue behavior of multilayer 4Y-TZP. The high-speed sintered material showed no deterioration compared with the conventional sintered monochrome material.

The aim of this cross-over investigation was to analyze the effect of virtual teaching using virtual reality (VR) within a dental learning environment by preclinical students with or without dental professional experience on test performance.Preclinical students (N = 82) were randomly divided into two groups for cross-over testing of tooth morphology knowledge: (a) anterior VR-group (group 1) using the VR-glasses as an additional learning tool for the anterior tooth morphologies and (b) posterior VR-group (group 2) using it for the posterior tooth morphologies also in addition to conventional learning. All students used the VR-glasses for 1 week independent of time and location depending on group. The students had to recognize teeth (anterior or posterior within two separate tests after three [anterior test] and 6 weeks [posterior test] of practical course) and note the tooth number and characteristics in written form. Former dental experience (dental technician/assistance) was noted. Test results were analyzed to quantify the effect of virtual teaching on test scores. Data were analyzed with the Kolmogorov-Smirnov and Mann-Whitney U test (p = 0.05).By differentiating the two student groups (use of VR glasses for anterior/posterior teeth) within the dental experience group, significantly better test results (p = 0.040) were shown for group 1 in the total posterior teeth test score. Furthermore, no other significant differences, but a possible tendency, in the test results and thus no effect of the use of the VR glasses on both VR groups could be analyzed (p ≥ 0.051).Using the VR tooth learning environment predominantly did not lead to a significant improvement of test results. Anterior teeth test scores predominantly showed significantly better results than posterior teeth test scores.

PURPOSE The aim of this study was to evaluate the efficiency of occlusal and interproximal adjustments of single implant crowns (SIC), comparing a digital cast-free approach (CF) and a protocol using 3D printed casts (PC). MATERIALS AND METHODS A titanium implant was inserted at position of lower right first molar in a typodont. The implant position was scanned using an intraoral scanner and SICs were fabricated accordingly. Ten crowns (CF; n = 10) were subject to a digital cast-free workflow without any labside occlusal and interproximal modifications. Ten other identical crowns (PC) were adjusted to 3D printed casts before delivery. All crowns were then adapted to the testing model, simulating chair-side adjustments during clinical placement. Adjustment time, quantity of adjustments, and contact relationship were assessed. Data were analyzed using SPSS software (P < .05). RESULTS Median and interquartile range (IQR) of clinical adjustment time was 02:44 (IQR 00:45) minutes in group CF and 01:46 (IQR 00:21) minutes in group PC. Laboratory and clinical adjustment time in group PC was 04:25 (IQR 00:59) minutes in total. Mean and standard deviation (±SD) of root mean squared error (RMSE) of quantity of clinical adjustments was 45 ± 7 µm in group CF and 34 ± 6 µm in group PC. RMSE of total adjustments was 61 ± 11 µm in group PC. Quality of occlusal contacts was better in group CF. CONCLUSION Time effort for clinical adjustments was higher in the cast-free protocol, whereas quantity of modifications was lower, and the occlusal contact relationship was found more favourable.

Ectodermal dysplasia (ED) is one of the congenitally syndromic diseases with dental anomalies. This syndrome manifests in various forms and usually requires early restorative therapy to restore esthetics and function in young patients. The restorative approaches vary greatly and range from minimally invasive shape corrections using composite build-ups and removable partial or complete dental prostheses, to implantologic solutions, always based on the syndromic expression, the age of the patient, the residual growth, as well as the dentition itself. The present case report presents an innovative prosthetic management of a young patient suffering from ED with permanent tooth aplasia and persistent primary teeth using maxillomandibular individually veneered tooth-colored CAD/CAM polycarbonate splints. The CAD phase has been significantly improved by including the analysis of 3D face scans. This advanced technical development makes it possible to avoid any time-consuming try-in and start directly with the splint production, ensuring a much faster complete rehabilitation and support for the young patient.

While various zirconia-based alternatives are available today for the restoration of teeth and implants in the esthetic zone, each treatment approach could result in different optical behavior. To clinically demonstrate these differences, this case report describes a rehabilitation in the esthetic zone using several options of teeth- and implant-supported restorations. Conventional veneered zirconia crowns, high-translucent monolithic zirconia crowns, and minimally veneered high-translucent zirconia crowns were proposed and assessed under different light sources before cementation. The patient and clinical team achieved consensus on the minimally veneered high-translucent zirconia crowns, which were then cemented and have performed well over both tooth and implant substrates.

The timetable for placing a dental implant can be crucial in the reduction of resorption of the socket after an extraction. The association of immediate implantation with an implant that copies the anatomy of the extracted root seems to add benefits in limiting the hard and soft tissue changes that may occur. The purpose of this paper is to provide an overview of the historical development of all types of root analogue implants from their beginning to the present day. To our knowledge the first individualised ones were described in 1969. Later, the use of titanium instead of the polymers that were used to start with offered better bony integration, and showed that the selection of materials was a key factor in their success. Root analogue implants made from zirconia were also described when attempts were being made to improve aesthetics in the anterior regions. The more recent introduction of digital technology such as DICOM has allowed the fabrication of these implants in less time, and the combination with digital diagnostic options such as cone-beam computed tomography facilitated the fabrication of some types of implants before extraction that could be inserted immediately into the alveolar socket with optimal and safe 3-dimensional positioning. Currently digital planning allows the clinician to design the ideal implant and abutment, which reduces the need for tissue grafting in the surgical phase and gingival conditioning in the prosthetic phase.

Analyze and quantify the residual monomer elution of nine conventional and CAD/CAM (computer-aided design/computer-aided manufacturing) dental polymers during artificial aging. A total of 360 square–shaped specimens (14 × 12 × 2 ± 0.05 mm) were fabricated from eight CAD/CAM polymer blanks (n = 40): Avadent Base material, Avadent Teeth material, PMMA Multi blank, PMMA Mono blank, Temp Premium, Telio CAD, Ceramill Temp, Shofu Block HC, and conventional polymer PalaXpress. Specimens were aged in distilled water for 60 days at 37 °C and the evaluation of the residual monomer elution was made through UV spectrophotometry. Statistical analysis was carried out in the SPSS software. One-way ANOVA and Scheffe post hoc test were applied (α

Statement of problem Determining the relationship between variable thicknesses and the translucency of dental ceramics is essential for optimizing esthetics in different clinical situations. Purpose The purpose of this in vitro study was to analyze the relationship between layer thickness and translucency of 2 multi-layered monolithic zirconia materials and to develop an equation by which the grade of translucency can be calculated dependent on the materials' layer thicknesses in advance. Material and methods Two semisintered multi-layered zirconia blanks, namely KATANA Zirconia Super Translucent Multi-Layered Disk (Noritake Dental Supply Co, Ltd) and Zirconia Ultra Translucent Multi-Layered Disk (UTML) (Noritake Dental Supply Co, Ltd), were sectioned (N=96) to separate the 4 layers (n=12 per layer): enamel layer, transition layer 1, transition layer 2, body layer. All specimens were sintered in a furnace (M2 Plus; Thermo-Star) at 1500°C for 2 hours and automatically polished under water cooling up to P2400 for the thicknesses of 1.6, 1.3, 1.0, 0.7, and 0.4 mm. Transmittance of visible light was measured using a spectrophotometer (Lambda 35; Perkin Elmer). Data were analyzed using the Kolmogorov-Smirnov, 2-way ANOVA, and Scheffe post hoc tests (α=.01) and curve fitting. Results Analyzing the fitting of the values of the 8 material groups to the linear, exponential, and logarithmic curves, 7 of the 8 groups (not UTML body layer) fitted the most (R-square value closer to 1.0) to the logarithmic curve. Constants were obtained from the distance to the x-axis and the curvature. Conclusions The methodology of this study provided the materials' specific constants a and b by analyzing the translucency behavior of KATANA Super Translucent Multi-Layered Disk and Ultra Translucent Multi-Layered Disk in different thicknesses, allowing further translucency calculation by applying the developed formula and the constants.

Objective In severe congenital or acquired orofacial anomalies, both dental esthetics and function are usually compromised. In particular, the esthetic ideas of the final desired appearance may differ from patient to patient, as the human esthetic sensibility differs significantly. Especially in complex cases, digital technology today offers outstanding improvements and simplifications in craniomaxillofacial surgical and prosthetic treatments, leading to a wide range of planning and pretreatment options. Clinical considerations This case report describes a patient-oriented interdisciplinary craniomaxillofacial surgical and prosthetic treatment with noninvasive tooth-colored splints, a Le Fort I osteotomy, and a full-mouth rehabilitation to meet the patient's demand for better function as well as orofacial esthetics and harmony. Conclusions By means of the digitally planned Le Fort I intervention and completion of the prosthetic rehabilitation, it was possible to optimize esthetics and facial harmony. Clinical significance In complex cases, digital technology today offers outstanding improvements and simplifications in craniomaxillofacial surgery and prosthetic treatments, leading to a wide range of planning and pretreatment options. Computer-aided design/computer-aided manufacturing technology enables the fabrication of tooth-colored flexible polycarbonate splints that offer a noninvasive, removable, functional, and esthetic solution. In intricate cases involving craniomaxillofacial anomalies, often together with necessary orofacial surgeries or prosthetic treatments due to moderate to severe tooth wear, such digital preprosthetic treatment and planning options represent an important enhancement with more predictable results.

OBJECTIVE To analyze the impact of the color of a resin composite cement (RCC) on the optical properties of different computer-aided design and computer-aided manufacturing (CAD/CAM) ceramics. MATERIALS AND METHODS Specimens (N = 220, thickness: 0.9 ± 0.03 mm) were fabricated from: leucite (Initial LRF Block/IPS Empress CAD), lithium disilicate (Amber Mill/IPS e.max CAD), lithium metasilicate (Celtra Duo), and lithium alumina silicate ceramic (n!ce) in translucency levels HT and LT. All specimens were bonded with an RCC (Light+/Warm+). Color was analyzed (spectrophotometer) initially as well as after bonding of RCC with CAD/CAM ceramics using CIELab and CIEDE2000. Kolmogorov-Smirnov test, one-way ANOVA and t test served for analyzing (α = 0.05). RESULTS Highest impact on ΔE presented the choice of ceramic (ηp2 = 0.155/p

PURPOSE To assess the impact of different types of dental prostheses, including definitive and interim restorations, on oral health-related quality of life (OHRQoL) before and after prosthetic treatment. MATERIALS AND METHODS A total of 151 patients received prosthetic treatment at one of two German departments of prosthetic dentistry. The patients' OHRQoL was assessed using the German version of the Oral Health Impact Profile (OHIP-G53) at baseline (T0) and at 1 week (T1) and 3 months (T2) after treatment. Patients were divided into 10 subgroups according to their pre- and posttreatment status. The effect of the type (no prosthesis; fixed prosthesis; removable prosthesis) and duration of wear (definitive; interim) of the restorations was evaluated. Results were analyzed using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests with a significance level of P = .05. RESULTS The highest OHRQoL was recorded for patients with fixed restorations, as indicated by the fact that their OHIP scores were lowest. A significant improvement in OHRQoL (P ≤ .034) was observed for patients who needed prostheses and were then treated with removable or fixed restorations. The OHIP score was affected by a change in restoration type. Rehabilitation with definitive prostheses had a significant effect on posttreatment OHRQoL (P ≤ .006). CONCLUSION In general, prosthetic rehabilitation by use of fixed or removable prostheses resulted in an improvement in OHRQoL. The use of the same type of restoration before and after treatment had a positive effect on OHRQoL. If possible, a change of restoration type should be avoided. For patients who require permanent prostheses, the use of fixed and removable restorations is recommended. For oral rehabilitation, fixed restorations should be preferred in order to achieve best possible improvement of OHIP score.

To investigate the discoloration and surface properties of four CAD/CAM composite resins provoked by a variety of food solutions and cigarette smoke.A total of 74 specimens (N = 370) were prepared per material (Brilliant Crios [Coltene], CeraSmart [GC], Lava Ultimate [3M Espe], Shofu Block HC [Shofu], and SonicFill 2 [Kerr]). Discoloration (ΔE) was investigated with a spectrophotometer. Measurements were taken before immersion in the storage media for 2 weeks (carrot juice, curry, cigarette smoke, red wine, energy drink, and distilled water), immediately after immersion, and after manual polishing of the specimens following immersion. The mean surface roughness (Ra) was measured using a profilometer. Qualitative surface observation was performed with scanning electron microscopy (SEM). Data were analyzed using Kolmogorov-Smirnov, Mann-Whitney U, and one-way analysis of variance with Tukey post hoc tests.The highest influence on ΔE after immersion was observed by the storage medium (ηThe different materials reacted dissimilarly in the various storage media in terms of discoloration. Surface roughness increased after immersion and polishing. Neither discoloration nor surface roughness could be reset to default by manual polishing.

Medication-related osteonecrosis of the jaw (MRONJ) is a serious concern for dentists as well as maxillofacial surgeons. Therefore, the safety of dental implant placement in patient receiving antiresorptive drugs (ARDs) has been the subject of controversial debate for several years and remains a source of uncertainty for surgeons and patients. This consecutive case series assessed the clinical and radiographic outcomes of dental implants placed in patients under antiresorptive therapy. Patients who received at least one dental implant at the Department of Oral and Maxillofacial Surgery, Ludwig Maximilian University (LMU), Munich, Germany, between 2010 and 2019 with a history of current or past antiresorptive medication were included the study. The main outcomes were occurrence of MRONJ, implant success, and survival rate. A total of 16 patients were treated with 39 implants. No implant loss or MRONJ occurred in the respective patients. The reasons for antiresorptive intake were osteoporosis, malignancy, edema of bone marrow, or diffuse sclerosing osteomyelitis (DSO). MRONJ occurred neither around implants nor in other locations. Cumulative implant success was 92.6% (25 of 27). No subjective complaints or postoperative complications were documented. Mean bone loss was 0.60 ± 0.98 mm. The prevalence of peri-implantitis was 30% on patient level and 29.6% on implant level. None of the patients had failed implants. No major complications after implant placement under antiresorptives could be detected. As long as implant surgery follows a specific protocol, implant placement in patients treated with antiresorptive therapy seems to be safe and predictable.

This study tested and compared properties of six modern indirect veneering resin composites (VRC), namely Ceramage (Shofu), dialog Vario (Schutz Dental), Gradia Plus (GC Europe), in:joy (Dentsply), Signum composite (Heraeus Kulzer), and SR Nexco (Ivoclar Vivadent). Specimens were fabricated from dentin and enamel pastes and following properties were analyzed: (1) two-body wear (TB), (2) surface roughness (SR), (3) Martens hardness parameters (HM and EIT), and (4) translucency (T). The highest impact on HM and EIT was exerted by VRC brand (HM: ηP2=0.960/ EIT: ηP2=0.968; p

Objectives To investigate the edge chipping resistance (ECR) of six veneering composite resins after different treatment protocols. Materials and methods Rectangular bar specimens were manufactured from Ceramage Incisal (CER; Shofu), dialog Vario Occlusal (DIA; Schutz Dental), Gradia Plus Heavy Body Enamel (GRA; GC Europe), in:joy incisal (INJ; Dentsply Sirona Deutschland), SR Nexco Paste Incisal (SRN; Ivoclar Vivadent), and Signum composite enamel (SIG; Kulzer). ECR was determined after five treatment protocols: (1) no treatment, (2) after storage in distilled water at 37 °C for 7 days, (3) storage in distilled water with an additional 10 000 thermal cycles (5 °C/55 °C), and hydrothermal treatment at 134 °C at a water vapor pressure of 0.2 MPa for a duration of (4) 3.5 min or (5) 23.5 min. Force was applied with the universal testing machine ZHU 0.2 (Zwick Roell) mounted with a Vickers diamond indenter until the chip fractured off the specimen and ECR values were computed by dividing the applied maximum force by the distance to the center of the applied force. Fracture analysis was performed employing light microscope imaging. Univariate and one-way ANOVA, Scheffe and Tukey-B post hoc, and partial eta squared (ƞp2) were computed (p Results DIA presented consistently high ECR values, while CER showed low results. For some groups, seven days’ storage in water and hydrothermal treatment for 3.5 min led to higher ECR results than observed in the initial state, while an additional 10 000 thermal cycles and hydrothermal treatment for 23.5 min resulted in lower ECR values. Conclusions The examined veneering composite resins differed in regard to their mechanical properties, with DIA possessing the highest resistance to chipping. While post-processing can initially increase a material's edge chipping resistance, intensified treatment protocols reduced the mechanical properties of veneering composite resins.

OBJECTIVES This investigation evaluated the impact of multiple firings during the veneering process of all-ceramic restorations on the thermal properties and bond strength between veneering ceramics and zirconia. METHODS For the measurements of the coefficient of thermal expansion (CTE) prismatic specimens of four different veneering ceramics (ZRT/ZRO/HFZ/STR; N��=��40/n��=��10 per veneering ceramic) and rod-shaped zirconia specimens (N��=��2) were produced. 2 specimens of each veneering ceramic were fired 2, 4, 6, 8, and 10 times simulating dentine-firing. Measurements were performed in a dilatometer and glass transition temperature (Tg) was determined graphically. To analyze bond strength (BS), crack initiation test specimens were prepared using the same veneering ceramics and zirconia (N��=��600/n��=��150 per veneering ceramic). 30 specimens of each veneering ceramic were fired 2, 4, 6, 8, and 10 times. Half of them were thermocycled (5000 cycles, 5����C/55����C, 20s). The crack initiation test was conducted in a universal testing machine. Data was analyzed using ANOVA with partial eta squared statistics and post-hoc Scheff�� test as well as Pearson correlation test. RESULTS CTE was mostly affected by the choice of veneering ceramic (p��

BACKGROUND: While some medical associations provide guidelines for the implant-prosthetic rehabilitation of head and neck cancer patients, the circulation and implementation in the everyday routine of practicing dentists remain unknown. PURPOSE: To analyze patterns of care for the prosthetic rehabilitation of head and neck cancer patients after radiotherapy in German speaking countries. MATERIALS AND METHODS: An online survey consisting of 34 questions separated into three sections, (a) general inquiries, (b) treatment concepts, and (c) patient cases, was forwarded to university hospital departments for Prosthetic Dentistry and Oral and Maxillofacial Surgery, and members of different medical associations. Statistical differences between groups were analyzed using chi-squared test (P

Dental therapy of traumatically ankylosed maxillary anterior teeth with an additional slight root resorption represents a great challenge for the restorative team and requires intensive planning and communication between patient, dentist, orthodontist, periodontist, and dental technician. The inhibition of vertical growth often makes dental intervention indispensable. Porcelain laminate veneers have been successfully used for more than two decades, mainly on anterior teeth, and was the minimally invasive treatment option for the present case report. Preprosthetic planning with a digital approach of the width-length ratio and the red-white esthetics were important prerequisites for a satisfactory treatment result. The treatment goal was clarified using a wax-up and a corresponding template for intraoral verification with a mock-up. The template also served as a preparation guide. Despite all risk factors, including the endodontic treatment, the 3-mm intruded position, and the slight root resorption, the patient and the restorative team decided to restore the situation with two feldspathic-ceramic veneers to provide an esthetic, time-saving, nonsurgical process for the patient.

Objectives Full-arch rehabilitations in young patients suffering from dental agenesis should compensate for the reduced vertical dimension of occlusion and restore both esthetics and function at minimal biological cost. This requires precise planning and maximum patient compliance during the preprosthetic phase. The pretreatment period with tooth-colored splints promotes a predictable outcome of the final restorations. Clinical considerations: Thanks to better restorative materials and adhesive techniques and increased knowledge of how to preserve sound tooth structures, prosthetic dentistry has increasingly turned toward minimally invasive procedures. The present clinical case documents a minimally/non-invasive maxillary full-arch rehabilitation of an agenesis patient with multiple dental aplasia, primary tooth persistence, and deficits in bone growth. The patient was pretreated with a tooth-colored CAD/CAM polycarbonate splint. Adequate esthetics and function were achieved by two zirconia-based single-wing adhesive fixed dental prostheses to replace the upper lateral incisors, lithium disilicate ceramic partial crowns for the posterior regions, and two feldspathic veneers for the upper central incisors. Conclusions Non-invasive pretreatment with a removable tooth-colored splint realizes the treatment goal simply and safely, reduces treatment time, increases predictability, and facilitates the transfer of the prototype to the final restorations. New restorative options permit the minimally invasive treatment of such patients. CLINICAL SIGNIFICANCE A pretreatment with a removable tooth-colored splint offers a simple and safe way to define the treatment goal, reduces treatment time, increases predictability, and facilitates the transfer of the results to the final restorations even in complex cases. New restorative options permit minimally invasive treatments of young patients with multiple dental agenesis.