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The aim of this in vitro study was to evaluate the calcium and phosphorus concentrations in enamel surfaces before, during, and after treatment with in-office 35% hydrogen peroxide bleaching agents with 2% calcium gluconate (WCa) or without calcium gluconate (W). Twenty sound human third molars were divided into 2 groups of 10. The bleaching agents were applied to the tooth surfaces in accordance with the manufacturer's instructions: WCa, 40 minutes per day at 3 sessions with 7-day intervals; W, 3 × 15 minutes per day at 3 sessions with 7-day intervals. Enamel microbiopsies were performed prior to the bleaching treatment, immediately after each bleaching session (first, second, and third applications), and 7 and 14 days following the last bleaching treatment. The concentration levels of calcium and phosphorus in the microbiopsy specimens were recorded spectrophotometrically. There was a statistically significant decrease in the calcium concentration 7 days after the last bleaching treatment, but there was a recovery to baseline values at 14 days, regardless of the bleaching agent used (WCa and W). When W was used, there was no difference in the phosphorus concentration over time. The phosphorus concentration in the WCa group decreased after the third application, showing a significant difference from the W group at this time. However, an increase in the phosphorus concentration was observed in the posttreatment period, and no significant differences were observed between values at baseline and those at 14 days posttreatment. The in-office bleaching gel containing 2% calcium gluconate did not affect the calcium and phosphorus concentrations in enamel as compared to a calcium-free bleaching agent.

Chemomechanical caries removal, when compared with removal using conventional rotary instruments, seems to preserve healthy tooth structure with less trauma to the patient. This study performed in vivo analysis of the total number of microorganisms in dentin after the use of conventional or chemomechanical (papain gel) caries removal methods. Analyses were performed before caries removal (baseline), immediately after caries removal, and 45 days after caries removal and temporary cavity sealing. Sixty patients were selected for this study, each with two mandibular molars (one on each side) with occlusal caries of moderate depth, for a total of 120 teeth. For each patient, the carious lesion of one tooth was removed by conventional methods using low speed drills (Group 1). For the other tooth, a chemomechanical method was used (Group 2). Dentin samples were collected at the three intervals and subjected to microbiological culture in blood agar. For the total number of microorganisms in both groups, ANOVA and Tukey tests (which considered the baseline values as a covariable) showed a higher microbial count immediately after the preparation of the cavity compared to the count at 45 days (P < 0.05). For both groups, the total count of microorganisms in dentin decreased 45 days after placing the temporary cavity sealing.

This study sought to determine the antimicrobial susceptibility of Staphylcoccus aureus and viridans group streptococci strains collected from the forearm skin and saliva of 30 patients at high risk of endocarditis. Agar susceptibility tests of antibiotics routinely utilized in dentistry were used to verify antimicrobial resistance of bacterial strains. Of the Staphylcoccus aureus strains, 50% were resistant to ampicillin, 53.3% to amoxicillin, 60.0% to penicillin G, 13.3% to amoxicillin/clavulanate, 20.0% to azithromycin, 27.6% to clarithromycin, 23.3% to erythromycin, 3.3% to cefazolin, and 6.7% to clindamycin. Regarding streptococci, 16.7% of the strains were resistant to ampicillin, 16.7% to amoxicillin, 23.3% to azithromycin, 23.3% to clarithromycin, 30.0% to erythromycin, 13.3% to cefazolin, 26.7% to clindamycin, 16.7% to penicillin G, and 3.3% to amoxicillin/clavulanate. Pathogens associated with bacterial endocarditis exhibited elevated resistance rates against the antibiotics used for prophylaxis in dentistry.