New techniques of minimal caries removal have been developed with the advance of dentistry. However , the cariogenic residue could contribute to the formation of gaps and the survival of microorganisms in the tooth-restoration interface, possibiliting the progression of carious process or the development of secondary caries lesions. The objectives of this study are to evaluate the influence of the incorporation of sodium trimetraphosphate nanoparticles (TMP) and chlorhexidine (CHX) on antimicrobial and mechanical properties and in the ability to reduce demineralization of resin-modified glass ionomer cement (RMGIC) indicated to restoration. This study will be divided into three stages. For the first step, we will evaluate the antimicrobial property of cements with or without TMP (7 and 14 %) and CHX (1.25 and 2.5 % ) by means of the agar diffusion test and biofilm assays. In the second step, the compression strength, diametral tensile strength and hardness tests of the cements will be realized. In step 3 of the study, enamel blocks (4x3x3mm ) will be prepared from bovine incisors and selected by the initial hardness test. The especimens of cements containing TMP/CHX or not will be adapted to freshly-prepared enamel blocks and subjected to pH-cycling. Next, we will analyzed the surface hardness in longitudinal section and fluoride (F) concentration in enamel to verify the ability of the material to prevent demineralization. It will also determined the release of TMP and F and the hardness of materials. Parametric and non- parametric tests will be used after checking the homoscedasticity of the data ( p<0.05).
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