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STATEMENT OF PROBLEM: Polyetheretherketone (PEEK) can be used to support fixed dental prostheses. However, information about physicomechanical characterization is still scarce. PUR-POSE: The purpose of this in vitro study was to assess effects of different aging regimens/durations on roughness, solubility, water absorption, Martens hardness (HM), and indentation modulus/EIT on different computer-aided design and computer-aided manufacturing (CAD/CAM) polymers. MATERIAL AND METHODS: Forty standardized specimens of the following materials were fabricated: PEEK: Dentokeep (DK); hybrid material: VITA Enamic (EN); composite resins: LAVA Ultimate (LU) and an experimental CAD/CAM nanohybrid-composite resin (EX); poly(methyl methacrylate) (PMMA)-based: VITA CAD-Temp (CT); Telio CAD (TC), artBloc Temp (AT), and ZENOTEC ProFix (ZP). A nanofilledpolymer for interim restorations, Protemp 4 (CG), served as the control group. Specimens were stored in sodium chloride, artificial saliva, physiological saliva, and distilled water at 37°C for 1, 7, 14, 28, 90, and 180 days. Roughness, water absorption, HM, and EIT were investigated after each storage period; solubility was determined after 180 days only. Data were analyzed using weighted 3/2/1-way ANOVA and the post hoc Scheffé tests (=.05). RESULTS: Storage media had no effect on surface roughness and water absorption. Physiological saliva revealed the highest significant impact on solubility followed by artificial saliva, sodium chloride, and distilled water. Water absorption increased significantly with storage duration. PEEK showed the lowest solubility and water absorption values. The highest solubility was observed for the conventional polymer CG, and the highest water absorption was found for the composite LU. PMMA-based TC, ZP, CG, and AT showed the lowest HM and indentation modulus, followed by CT, and PEEK. The highest values were observed for the hybrid material EN, followed by LU and EX. CONCLUSIONS: The hardness parameters of PEEK were comparable with those of PMMA-based materials. group. Specimens were stored in sodium chloride, artificial saliva, physiological saliva, and distilled water at 37°C for 1, 7, 14, 28, 90, and 180 days. Roughness, water absorption, HM, and E IT were investigated after each storage period; solubility was determined after 180 days only. Data were analyzed using weighted 3/2/1-way ANOVA and the posthoc Scheffé tests (α=05).Results. Storage media had no effect on surface roughness and water absorption.Physiological saliva revealed the highest significant impact on solubility followed by artificial saliva, sodium chloride, and distilled water. Water absorption increased significantly with storage duration. PEEK showed the lowest solubility and water absorption values. The highest ! ! ! 2! solubility was observed for the conventional polymer CG, and the highest water absorption was found for the composite LU. PMMA-based TC, ZP, CG, and AT showed the lowest HM and indentation modulus, followed by CT, and PEEK. The highest values were ...

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Current management guidelines for the treatment of patients with Parkinson's disease (PD) are limited due to the lack of knowledge of factors that influence health-related quality of life (HRQL). To assess the HRQL of people with PD, and to systematically identify and evaluate those factors (other than disease severity and medication, which could have an impact), we undertook a cross-sectional, randomized selection, multicenter international survey of patients with PD, caregivers, and clinicians. Face-to-face interviews were conducted with subjects in six countries. Disease severity, medication, and other factors hypothesized to influence HRQL were assessed using a combination of specially developed questionnaires and validated instruments including the Parkinson's Disease Questionnaire-39 (HRQL), Hoehn and Yahr Stage (disease severity), and Beck's Depression Inventory (BDI; depression). Multiple linear regression models were used to demonstrate whether the factors investigated contribute significantly to HRQL. The results obtained indicated that Hoehn and Yahr stage and medication explained only 17.3% of the variability in HRQL of patients with PD, although both were significant (R(2) = 0.173, P < 0.05). Other factors increased the explanatory power to adjusted R(2) = 0.597, with BDI being the most significant predictor of variability in HRQL (adjusted R(2) = 0.582; P < 0.001), followed by "Satisfaction with the explanation of the condition at diagnosis" and "Current feelings of optimism" (both P < 0.05). These factors, in addition to disease severity and medication, explain 59.7% of the variability in HRQL across the population. In conclusion, depression (as measured by the BDI) in PD, "satisfaction with the explanation of the condition at diagnosis" and "current feelings of optimism" have a significant impact on HRQL. The completion of this initial analysis is the first step towards developing management guidelines that truly influence the HRQL of patients with PD.

Objectives: Digital technology is already playing an increasingly important role in the education of students. The present investigation examined the acceptance of preclinical students for learning dental morphologies in virtual reality (VR). Methods: The creation of the VR dental teaching environment was divided into 3 sections: (a) generation of the digital data; (b) creation of the VR dental learning environment for tooth morphologies; and (c) evaluation by preclinical students through questionnaires combined with visual analogue scale and fixed-answer options. Students of the Department of Prosthetic Dentistry of the University Hospital Munich were able to stay/interact in the VR dental learning environment for 10 minutes with VR headsets and hand controllers. The data were analyzed using the Kolmogorov−Smirnov test and exploratory data analysis using the median value and interquartile range. Results: Of the students, 34.9% stated that they understand dental morphologies much better, 57.1% better, and 7.9% equally well compared to using the traditional textbook. The students would be willing to spend about 500 euros privately for the VR equipment. The haptic and auditive teaching elements were evaluated more positively than the purely visual ones of the integrated information boards. Conclusions: Learning in the VR dental learning environment showed a high level of acceptance among all students and should be integrated as a fixed element in the dental curriculum. A further development for use independent of time and place is desirable.

Reymus M, Liebermann A, Diegritz C. Virtual reality: an effective tool for teaching root canal anatomy to undergraduate dental studentsa preliminary study.

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