In vitro evaluation of the effects of a fluoride-releasing composite on enamel demineralization around brackets

ObjectivesThe aim of this in vitro study was to evaluate the effectiveness of a fluoride-releasing bonding agent in inhibiting enamel demineralization around orthodontic brackets after the exposure to a demineralizing solution.Materials and methodsTwenty-six extracted upper molars were bonded with two different composites: Transbond XT (TXT) and Transbond Plus (TPlus), fluoride-releasing (both 3 M Unitek, Monrovia, CA, USA). The samples were exposed to an acid lactic solution for three days and then subjected to Metallographic Optical Microscope (MOM) and Scanning Electron Microscope/Energy Dispersive X-Ray (SEM/EDX) analyses. Enamel surface was examined in different areas: un-treated, etched and primer-painted, un-treated area with no acid exposure, central area with bracket bonded. The maximum demineralization depths and the fluoride content at 100, 200 and 300 μm depth were evaluated.ResultsMOM analysis showed statistically significant (p < 0.001) differences in demineralization depth for TPlus group compared to TXT group with lower values for the first one. EDX analysis confirmed the presence of fluoride in TPlus group.ConclusionsThe fluoride content of TPlus appeared able to weakly reduce the enamel demineralization.