RESUMO
OBJECTIVES: This in situ study aimed to investigate the effect of a sugar-free antibiotic suspension containing amoxicillin and clavulanic acid on enamel hardness of human primary teeth simulating different conditions of cariogenic challenge. MATERIALS AND METHODS: A crossover, partially double-blind study was conducted in three phases of 14 days each, during which 11 volunteers wore palatal devices containing six dental enamel blocks covered with plastic meshes to allow biofilm formation. Dental blocks were extraorally submitted to treatment with a 20 % sucrose solution at three different daily frequencies of exposure (0, 3, and 8 times/day), and to the antibiotic suspension or its excipients at an 8-h time interval application regimen. On the 14th day of each phase, the blocks were removed for enamel analysis (surface and cross-sectional microhardness--SMH and CSMH). RESULTS: The antibiotic suspension showed significant higher SMH and CSMH values than the excipients (p < 0.05; Wilcoxon), regardless of the frequency of sucrose exposure. Sucrose exposure did not account for further enamel demineralization both for antibiotic and excipients (p > 0.05; Friedman). CONCLUSIONS: A protective effect of the antibiotic suspension on enamel demineralization was verified because its excipients alone promoted more pronounced surface and subsurface enamel demineralization, even in the absence of sucrose exposure. CLINICAL RELEVANCE: The use of a sugar-free amoxicillin/clavulanic acid suspension may promote a protective effect on primary enamel demineralization probably due to its topical effect on dental biofilm.