RESUMO
CONTEXT: Epigallocatechin-3-gallate (EGCG) is a flavonoid extracted from green tea that demonstrated antimicrobial activity. AIMS: To evaluate the efficacy of EGCG 0.5%, 1%, and 2% concentrations as an antimicrobial solution in dentin caries-like lesions induced in a bacterial-based in vitro model. MATERIALS AND METHODS: Twenty-five human dentin specimens were submitted to a microbial-based caries model by immersion in brain heart infusion (BHI) broth inoculated with Streptococcus mutans UA159, for 5 days. After the demineralization period, the specimens were randomly divided into groups: Group I: 0.9% saline solution; Group II: 2% chlorhexidine digluconate; Group III: 0.5% EGCG; Group IV: 1% EGCG; and Group V: 2% EGCG. After the treatments, carious dentin samples were harvested from dentin specimens and analyzed by colony-forming unit (CFU) counts. Data were analyzed by ANOVA and Tukey's test. RESULTS: Log reduction values (SD, CFU.mg(-1)) for Groups I-V were: 5.02 (0.16), 3.96 (0.43), 4.74 (0.26), 4.89 (0.56), and 4.91 (0.40), respectively. There was no statistical difference between the EGCG concentrations and saline solution (P > 0.05). Furthermore, there was no statistical difference between EGCG concentrations (P > 0.05). However, there was a statistically significant difference between the chlorhexidine digluconate group and the other groups (P < 0.05). CONCLUSION: EGCG at the studied concentrations were not effective in eliminating S. mutans from dentin caries-like lesions.
RESUMO
OBJECTIVES: This study evaluated the immediate and 3 month clinical effects of a low-level gallium-aluminum-arsenide (GaAlAs) laser and a 3% potassium oxalate gel for the treatment of dentinal hypersensitivity. MATERIALS AND METHODS: A total of 164 teeth from 30 patients with clinical diagnoses of dentinal hypersensitivity were selected for this randomized, placebo-controlled, double-blind clinical study. The teeth were randomized to three groups: GaAlAs laser, oxalate gel, and placebo gel. The treatment sessions were performed at 7 d intervals for four consecutive weeks. The degree of sensitivity in response to an air blast and tactile stimuli was assessed according to a visual analogue scale at baseline, immediately after the fourth application, and then 3 months after the fourth application. The reductions in dentinal hypersensitivity from baseline at the two follow-up assessments were evaluated as the main outcome. RESULTS: In both the active and control groups, there were statistically significant reductions in dentinal hypersensitivity immediately after and 3 months after the treatments, when compared with the hypersensitivity at baseline. No significant differences among the three groups could be detected in their efficacy at either the immediate or 3 month evaluations irrespective of the stimulus. CONCLUSIONS: The treatments under study were effective for reducing dentinal hypersensitivity, and longer observational periods could enhance the ability of studies to detect differences between active and placebo groups.