Demineralization of enemal adjacent to orthodontic brackets following laser irradiation, fluoride and their combination

Abstract

The demineralization of enamel adjacent to orthodontic brackets is a clinical problem which can lead to some esthetic concerns after the treatment causing the patient to receive different restorations. In addition to conventional fluoride treatment modalities, the use of different laser types have been developed for caries preventive procedures nowadays. As no study assessed the effect of Er,Cr:YSGG laser on acid resistance of enamel adjacent to orthodontic brackets, the present study investigated the effect of laser, fluoride and combination of two techniques on the demineralization of enamel adjacent to orthodontic brackets. Materials and Methods: In this in vitro study, 60 healthy human premolars were selected and the brackets were bonded to them. The specimens were randomly assigned to 4 groups (n=15): topical APF application, laser irradiation, laser + fluoride and control specimens. Er,Cr:YSGG laser was irradiated at 12.5 mJ pulse energy without water spray while APF gel was applied on the specimen surfaces for 4 minutes. All specimens individually were demineralized for 10 days in an acetate buffer solution with pH=4.8 and the calcium content were subsequently determined with atomic absorption spectrometry. The data were subjected to one-way analysis of variance and Tukey post hoc test. Results: The mean calcium content of specimens in APF fluoride application was 6.521.24 PPM, in irradiated with Er,Cr:YSGG laser was 6.660.64 PPM, , in laser + fluoride specimens was 6.210.77 PPM and in control ones was 7.090.56 PPM. The calcium content of specimens subjected to laser irradiation and fluoride application was significantly lower than control specimens (p=0.029), while no other significant differences were noted in the next comparisons. Conclusion: Fluoride application following laser irradiation significantly increased acid resistance of specimens compared to control ones. Although Er,Cr:YSGG laser irradiation and fluoride application alone wasn`t statistically significant, but more study using other different parameters is recommended.