Richtersaleh2762

OBJECTIVES This study examined the influence of different light-curing units (LCUs) and exposure times on the microhardness across bulk-fill resin-based composite (RBC) restorations in a molar tooth. METHODS AND MATERIALS Tip diameter, radiant power, radiant exitance, emission spectra, and light beam profile were measured on two single-emission-peak LCUs (Celalux 3 and DeepCure-S) and two multiple-peak LCUs (Bluephase 20i and Valo Grand). A mold was made using a human molar that had a 12-mm mesial-distal length, a 2.5-mm deep occlusal box, and two 4.5-mm deep proximal boxes. Two bulk-fill RBCs (Filtek Bulk Fill Posterior and Tetric EvoCeram Bulk Fill) were photoactivated for 10 seconds and for 20 seconds, with the light guide positioned at the center of the occlusal surface. selleck Microhardness was then measured across the transverse surface of the restorations. The light that reached the bottom of the proximal boxes was examined. Data were statistically analyzed with the Student t-test, two-way analysis of variance, and the Tukey post hoc test (α=0.05). RESULTS The four LCUs were different regarding all the tested characteristics. Even when using LCUs with wide tips and a homogeneous beam profile, there were significant differences in the microhardness results obtained at the central and proximal regions of the RBCs (p less then 0.05). LCUs with wider tips used for 20 seconds produced higher microhardness values (p less then 0.05). The multiple-peak LCUs produced greater hardness values in Tetric EvoCeram Bulk Fill than did the single-emission-peak LCUs (Celalux 3 and DeepCure-S). Results for the light measured at the bottom of proximal boxes showed that little light reached these regions when the light tip was positioned at the center of restorations. CONCLUSIONS Curing lights with wide tips, homogeneous light beam profiles, and longer exposure times are preferred when light-curing large MOD restorations. Light curing from more than one position may be required for adequate photopolymerization.OBJECTIVE The aim of this study was to evaluate the clinical performance of class II restorations made using pure ormocer and methacrylate composites in a period of 24 months, using a split-mouth double-blinded randomized design. METHODS AND MATERIALS Thirty patients received two class II restorations (n=60) performed with different composites GrandioSO (methacrylate, nanohybrid) and Admira Fusion (pure ormocer, nanohybrid). The universal adhesive system (Futurabond M+) was applied in all restorations using the self-etching mode. The composites were placed by the incremental technique. The restorations were evaluated using the FDI World Dental Federation criteria after 7 days and 6, 12, and 24 months postoperatively. RESULTS After 24 months, 23 patients attended the recall and 46 restorations were evaluated. Fisher's statistical analysis (5%) showed no difference between the materials. One pure ormocer restoration and one methacrylate restoration presented small fractures. Only one tooth suffered a fracture of the remaining tooth structure. Admira Fusion presented, respectively, 100%, 95.66%, and 100% of acceptable performance in general scores for esthetic, functional, and biological properties. GrandioSO presented, respectively, 100%, 91.31%, and 95.66% of acceptable performance in the same scores. CONCLUSION After 24-month follow-up, nonsignificant differences between the tested composites was detected. Both materials provided acceptable clinical performance in class II restorations.BACKGROUND This study investigated the hardness and color stability of five resin composites subjected to different polishing methods following immersion in distilled water or lactic acid for up to three months. METHODS AND MATERIALS Three nanohybrid, Paradigm (3M ESPE), Estelite Sigma Quick (Tokuyama), Ice (SDI), and two microhybrid, Filtek P60 and Filtek Z250, composites were examined. Disc-shaped specimens (10×1.5 mm) were prepared and immersed in distilled water for 24 hours then polished using either silicon carbide paper, the Shofu polishing system or were left unpolished (control). The CIE values and microhardness were determined using a spectrophotometer and digital Vickers hardness tester, respectively (n=10) after one, 45, and 90 days of storage in distilled water or lactic acid. Data were analyzed using analysis of variance, Tukey test, and Pearson correlation coefficient. RESULTS Ice exhibited the greatest color change, yet Paradigm and Filtek P60 demonstrated the least. Overall, discoloration of tested materials was multifactorial and the effect of storage media depended on the material, polishing method and time interval. The greatest hardness was obtained for Paradigm and the lowest for Estelite. Hardness was found to be significantly higher in lactic acid after 45 days (p=0.014) and even higher after 90 days (p less then 0.001) compared with distilled water. CONCLUSIONS An acidic environment did not adversely affect color stability or microhardness of the resin composites. There was a significantly mild reverse correlation between hardness and color change in both storage media.The use of the self-etching ceramic primer combines the stages of acid conditioning and silanization in cementation procedures of ceramic restorations. The protocol is a simpler and safer alternative to the conventional protocol for surface treatment of silica-based ceramics. This case report describes the steps of an esthetic rehabilitation with ultrathin veneers and full crown based on lithium disilicate treated with a ceramic primer (Monobond Etch & Prime, Ivoclar Vivadent, Schaan, Liechtenstein). After two years of clinical follow-up, the restorations presented satisfactory esthetic and functional performance, color stability, surface and marginal integrity, and absence of cracks and debonding. More research is needed to investigate the clinical performance and longevity of the ceramic restorations treated with self-etching ceramic primers.OBJECTIVE The objective of this study was to evaluate the effect of erosion or erosion-abrasion on bioactive materials and adjacent enamel/dentin areas. METHODS AND MATERIALS Enamel and dentin blocks (4×4×2 mm) were embedded side by side in acrylic resin, and a standardized cavity (1.2×4×1.5 mm) was prepared between them. Preparations were restored with the following materials composite resin (Filtek Z350, control); experimental composite containing di-calcium phosphate dihydrate particles (DCPD); Giomer (Beautifil II), high viscosity glass ionomer cement (GIC, Fuji IX); and a resin-modified GIC (Fuji II LC). The specimens were submitted to two cycling models (n=10) erosion or erosion-abrasion. The challenges consisted of five-minute immersion in 0.3% citric acid solution, followed by 60-minute exposure to artificial saliva. Toothbrushing was carried out twice daily, 30 minutes after the first and last exposures to acid. Dental and material surface loss (SL, in μm) were determined by optical profilometry. Data were analyzed with Kruskal-Wallis and Dunn tests (α=0.