Effect of hydrogen peroxide on color and whiteness of resin-based composites.

OBJECTIVE: To evaluate the influence of a 35% hydrogen peroxide gel on color and whiteness changes of resin-based composites (RBC). MATERIALS AND METHODS: Discs (n = 10; shade A3.5 enamel; and 8 mm diameter and 2 mm thick) were fabricated from three RBC (DF- Durafill, Heraeus Kulzer; ED- IPS Empress Direct, Ivoclar Vivadent; and AP- Amelogen Plus, Ultradent Products). Three subgroups were obtained for each RBC: before bleaching (T0 ) and after first (T1 ) and second (T2 ) bleaching applications. A dental spectrophotometer (VITA Easyshade, Vita Zahnfabrik) was used to obtain CIELAB color coordinates and whiteness index for dentistry (WID ) in all periods. CIELAB ( ΔEab* ) and CIEDE2000 (ΔE00 ) color differences were also obtained. Perceptibility (PT) and acceptability (AT) thresholds were used to analyze values of ΔEab* , ΔE00 , and ΔWID . Two-way analysis of variance (ANOVA; for L*, a*, b*, and WID ) and one-way ANOVA and Tukey tests (for ΔEab* and ΔE00 ) were used to analyzed the results (α = 0.05). RESULTS: L* and WID values from all RBC did not change after bleaching applications (T1 and T2 ) (P > .05). There were no significant differences in color differences ( ΔEab* and ΔE00 ) among all RBC evaluated after bleaching applications (T1 -T0 and T2 -T0 ; P > .05). Regardless of the RBC, mean values of ΔE00 between all different periods were always below 50%:50% PT value. CONCLUSIONS: The 35% hydrogen peroxide bleaching gel influences on color and whiteness of resin-based composites. However, color changes were not clinically perceived and whiteness variations were clinically acceptable. CLINICAL SIGNIFICANCE: Patients should be advised that existing composite restorations might not match the natural tooth color after bleaching, and their replacement may be required.

Are there universal restorative composites for anterior and posterior teeth?

OBJECTIVE: This retrospective, longitudinal clinical study investigated the longevity up to 20 years of posterior restorations placed with 3 universal composites (Charisma, Herculite XR, Z100) and of anterior restorations placed with 2 universal composites (Charisma, Herculite XR). METHODS: Records from 90 patients were retrieved from a private practice (374 posterior, 219 anterior restorations). Clinical evaluation was performed by the FDI criteria. Survival analysis was assessed using Kaplan-Meier method and Log-Rank test, and factors associated with failure by multivariate Cox regression with shared frailty. RESULTS: In the first 10 years, almost 95% of the restorations were satisfactory, showing increased failure thereafter. Charisma showed the most failures in anterior and posterior areas. Annual failure rates varied between 0.3% and 2.5%, with slightly better performance for anterior restorations. Fracture (posterior) and aesthetics (anterior) were the main reasons for failure. CLINICAL SIGNIFICANCE: Differences were observed between restorative materials with different properties, but these became apparent only after more than 10 years of clinical service. The present study provides evidence that in a patient group with low caries risk, anterior and posterior restorations placed with universal composites may have excellent long-term clinical performance.