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.

Management of an uncomplicated crown fracture by reattaching the fractured fragment-Case report.

Coronal fractures of the anterior teeth are common sequelae of traumatic dental injuries. Reattachment of fractured tooth fragments using dental adhesive techniques offers some advantages, including restoration of the function, esthetics, shape, texture, and brightness of the surface. The present report describes a clinical case of reattachment with a 4-year clinical and radiographic follow up in a permanent maxillary central incisor with an uncomplicated crown fracture. Fragment reattachment is a conservative procedure, preserving esthetics and functionality, and it can provide an immediate positive emotional response from the patient.