Influence of Different Finishing-Polishing Procedures and Thermocycle Aging on the Surface Roughness of Nano-Ceramic Hybrid CAD/CAM Material.

Aim: The aim of this study was to evaluate the effectiveness of different finishing-polishing (FP) procedures on reducing surface roughness of nanoceramic hybrid CAD/CAM material before and after thermocycle (TMC) aging. Materials and Methods: Nano-ceramic hybrid CAD/CAM specimens were subjected to 8 different (2-glaze and 6-mechanical) FP procedures as follows (n=20): 1. Optiglaze (OG) 2. Diamond glaze (DG), 3. Vita Enamic Polishing Set (VE), 4. VE+Gradia Diapolisher paste (VE-G) 5. VE+Super-Snap SuperBuff (VE-S) 6. Sof-Lex Disc kit (SL) 7. SL+Gradia Diapolisher paste (SLG) 8. SL+Super-Snap SuperBuff (SL-S). Surface roughness of each specimen was measured by using a contact profilometer. All specimens were artificially aged with TMC (5000 cycles, 5°C/55°C) and surface roughness measurements were repeated. One extra specimen from each group before and after TMC was examined with SEM. Surface roughness data were analyzed by repeated measures ANOVA, dependent t-test and Tukey test. Results: Significantly higher mean Ra values were found for groups OG and DG compared to other groups (P<0.05). Differences between glaze groups and differences between mechanical FP groups were not significant (P>0.05). Groups SL-S and DG demonstrated comparable results before and after TMC (P>0.05). SEM analysis revealed that surfaces of VE-S and SL-S groups were smooth and free of scratches. Conclusions: Mechanical FP procedures were more effective in reducing surface roughness of nanoceramic hybrid CAD/CAM material than glaze applications. Sof-Lex kit followed by Super-Snap SuperBuff disc application can be recommended as the mechanical FP procedure of choice considering that this method provided smooth surfaces that were maintained after TMC.

EPA Consensus Project Paper: Optical Impression Accuracy of Preparations for Fixed Prosthodontics: A Systematic Review.

INTRODUCTION: This systematic review aimed to evaluate the accuracy of different optical impressions of tooth preparations. METHODS: An electronic search in PubMed, Web of Science, Scopus, Medline Complete, and ScienceDirect was performed to identify articles comparing the accuracy of different optical impressions (OI) published up to the 1st of March 2022. The inclusion criteria enclosed the accuracy of optical impressions acquired for tooth-supported fixed prosthodontics. Exclusion criteria were defined as studies focused on orthodontic impressions and implant-supported restorations. This review was registered to Prospero; CRD42021287758. RESULTS: Eleven included studies had in vitro design and a low risk of bias. Considering scanned objects, 5 studies evaluated the accuracy based on a single preparation, 2 studies evaluated the accuracy of OIs based on fixed partial denture (FPD) restoration, 3 studies included both single preparation and preparations to receive FPD restorations, and 1 article included a fullarch scan. Mean values of the trueness and precision of OI systems varied according to methodological differences. CONCLUSIONS: Optical impression has certain advantages. However, stating a particular optical impression system as the most accurate or superior to conventional impression is not feasible because of the heterogeneity of the accuracy results presented in this systematic review.