Efecto de los fluoruros en la composición química del esmalte dental posblanqueamiento.

Background: It has been reported that dental bleaching causes changes in the chemical composition of enamel and, in consequence, in the dental micromorphology, superficial hardness, and immediate bond to dental enamel. Objective: Identify changes in the chemical composition of the enamel surface after application of 38% hydrogen peroxide, and determine the effect of fluoride application on ion concentration. Methods: Percentage of calcium, chlorine, phosphorus and oxygen was evaluated through scanning electron microscopy in 36 healthy premolars in three stages: 1) intact enamel; 2) after applying bleaching agent; and 3) after applying sodium fluoride rinse and gel. Data were analyzed with the SIGN test (MINITAB15 statistical package) (confidence level = 95%). Results: Bleaching caused changes in the enamel composition. Oxygen increased 9.43%, while calcium, phosphorus and chlorine decreased 9.25%, 0.9%, and 0.41%, respectively. Calcium increased 4.29% with the application of fluoride rinse and 4.89% with neutral gel. Both presentations of fluoride produced increases in oxygen and phosphorus decreases. No statistically significant differences were found between fluorides. Conclusions: There are changes in the enamel composition associated with the use of 38% hydrogen peroxide. Weight percentage of important elements decreased and, as a result of the redox reaction, oxygen increases. With the application of fluoride, regardless of its presentation, calcium increases. Oxygen decreases, which is attributable to the post-bleaching time. [ABSTRACT FROM AUTHOR]