Effect of Office Bleaching Systems on Chemical Compositions of Enamel and Dentin: an in Vitro Study

Background and Aim: To determine the change in the mineral component of enamel and dentin as well as to evaluate the differences in surface texture of the same dental hard tissues following three office bleaching procedures in vitro. Materials and Methods: Sixty extracted human anterior teeth were used. Thirty teeth were used as enamel samples; the buccal surfaces of the remaining 30 teeth were abraded and used as samples for dentin. Prior to bleaching treatments, calcium (Ca), phosphorus (P), potassium (K), sodium (Na), magnesium (Mg), fluoride (F), and oxygen (O) levels of each sample were measured using an energy dispersive X-ray spectrometry system (EDS). The teeth were then randomly allocated into three groups; GI: chemically activated office bleaching system (OBS), GII: light activated OBS, GIII: diode laser activated OBS. Following the bleaching treatments, measurements were repeated. Wilcoxon signed rank and Kruskal-Wallis tests were used to analyze the data statistically. Results: GI decreased the F level of enamel and F, Na, P, K, Ca levels of dentin. GII reduced the F level of enamel and Na levels of dentin. GIII created a reduction in F and K levels on enamel and F, Na, K, Ca levels on dentin. The use of bleaching systems did not make any difference in Na, Mg, P, Ca levels of enamel and Mg levels of dentin. SEM observations revealed no deleterious effect on enamel and dentin. Conclusion: The use of office bleaching agents and activation mode of the bleaching systems used could affect the chemical composition of dental hard tissues.