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Aim of the study: The aim of this study is to evaluate the resistance of different marginal fit geometries for a provissional fixed dental prothesis, which can have an impact on the periodontal health. Materials and methods: Acording to the principles of the tooth preparation, four types of marginal design were made: feather edge, rounded shoulder, chamfer and heavy chamfer. Using a direct technique, prepared teeth were poured into metal abutments, temporary composite resin crowns were made and cemented. All four abutments were analyzed using theoretical and experimental methods. Results: The results obtained from the mechanical tests were more reliable than those obtained from numerical analyses. A chamfer marginal finish line a pre prosthetic periodontal therapy can have greater impact on the soft tissue healing process. Conclusions: These preliminary studies enhance the idea of differentiating preparations for distinctive alternative prosthetic treatment plans. [ABSTRACT FROM AUTHOR]

Aim of the study In the field of digital dentistry, Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) systems have changed the fabrication of prosthetic restorations by fulfilling both the aesthetic requirements and mechanical performance. This study aims to highlight, by conducting a chromatic evaluation of zirconium oxide when altering the sintering parameters Materials and methods Four groups of zirconium oxide each group formed by 5 copings were made through milling and Exocad digital design software. The design was completed and the files were processed with the Zeno 4030 M1 milling machine (I-MES Wieland). Following milling, the copings were sintered in HTS MIHM-VOGT furnace at a maximum sintering temperature of 1650°C and heating rates of 30°C/min or a rapid rate of 90°C/min. Controlled cooling prevented rapid temperature decrease, thereby minimizing internal stress. Modifications of time and temperature parameters were applied to groups 2, 3, and 4. Chromatic analysis of the specimens was registered with the Vita Easy Shade spectrophotometer. Results It was found that adjustments in sintering temperature and timing are significantly affecting the chromatic outcomes of the non-metallic zirconium structures. Temperature adjustments facilitate the coalescence of zirconium oxide particles and the formation of a robust structure, with changes in it affecting the optical behaviour of the structure. Deviations from the optimum temperature and sintering timing parameters negatively affect the shade. Conclusions In conclusion, milled and sintered zirconium oxide structures can achieve aesthetic excellence, provided by the sintering protocol when the temperatures and sintering furnaces are accurately calibrated. [ABSTRACT FROM AUTHOR]

Aim of the study This manuscript summarizes important ethical considerations relevant to embryo research. The aim of this study was to assess the opinion of three categories of doctors regarding the ethical and legislative implications of scientific research on human embryos. Material and methods To assess the opinion of doctors about the use of human embryos in research, from a related point of view, a questionnaire with 10 questions was made. Each question has three possible answers. Results The results were analyzed according to the age criterion, as follows:18-25 graduated doctors; 26-45 young doctors; 45-65 adult doctors with experience in the field. Conclusions Following the interpretation of the questionnaires, it can be concluded that, in view of the group of people considered, graduated doctors have more knowledge about the current legislation and ethical measures that accompany scientific studies on human biological material. Also, the third group of doctors with experience in the field tend to show the same knowledge as the first group. [ABSTRACT FROM AUTHOR]