بررسي آزمايشگاهي تاثير مواد و ايتال بليچينگ بر استحكام خمشي كمپلكس مينا و عاج

Effects of vital bleaching agents on the flexural Strength of enamel and dentin complex

Background & Aim: Vital bleaching agent could effect on physical and mechanical properties of teeth. The purpose of this in vitro study was to evaluate the effect of different concentrations of vital bleaching agents on the flexural strength of enamel and dentin complex. Methods & Materials: This in vitro study was an interventional with a parallel design. 2x3x8 mm beams were cut from facial surface of previously extracted bovine incisors. The dentinal part of the teeth was covered by wax. The specimens were divided into four groups of 12 based on the kind of bleaching agent. Group A) 9% Perfecta Bravo, Group B) 15 % Opalescence, Group C) 20% Opalescence and Group D) Control. The experimental groups were immersed in vatial bleaching agent for a period of two weeks according to the instruction of manufacturer. The control group was immersed in synthetic saliva. Flexural testing was performed 24 hours after the last treatment using an Instron testing machine with a crosshead speed of 0.2 mm/min. The results were analyzed by one way ANOVA (a--0.05). Results: The mean of data (Mpa) were A: 123.99, B: 124.87,C: 162.98 and D: 141.26. After using a nonparametric analysis Kolmogrov - Smirnov for acceptance of normal assumption (a=0.05), one way ANOVA showed that there was no significant difference among groups (P>0.05). Conclusion: Different concentration of bleaching agents had no significant effect on flexural strength of enamel and dentin complex.