RESUMO
PURPOSE: To evaluate the effect of varnish with different chlorhexidine concentrations on the demineralization of dentin surfaces in situ. METHODS: An intraoral model was used to study the ability of chlorhexidine to prevent demineralization. Dentin specimens from extracted human teeth were treated with chlorhexidine varnish and exposed to the oral environment of 47 subjects. The dentin specimens were prepared from the cervical regions of 47 third molars, sterilized by irradiation with 60 GY and mounted in intraoral appliances worn by the subjects. Before the delivery of the appliance, the specimens and participants were treated once with one of the three different varnishes (according to the manufacturer's instructions). All participants were randomly assigned to one of the three groups: (1) EC 40 (n=16), (2) Cervitec (n=15), or (3) ChemFil Varnish (control group, n=16). The appliances were worn day and night for 3 weeks. At mealtimes, the appliance was stored in 10% sucrose solution. After exposure to demineralization, the dentin surface was evaluated by microradiography to assess the depth of the lesion (microm) and the loss of mineral (Vol% microm). Data analysis was accomplished using one-way ANOVA plus LSD testing (P< 0.05). RESULTS: Both chlorhexidine varnishes EC 40 and Cervitec resulted in significantly decreased mineral loss and lesion depth in dentin than the control. In addition, EC 40 treated specimens demonstrated significantly reduced lesion depth compared to Cervitec and the control (109.22 microm vs. 139.23 microm and 178.21 microm).
