Viability of Intratubular Bacteria after Chemomechanical Caries Removal

Introduction: The aim of this study was to assess the effect on bacterial viability within dentinal tubules after the application of sodium hypochlorite (NaOCl)- or enzyme-based chemomechanical caries removal agents. Methods: Twenty-five caries-free dentin discs prepared from 25 sound maxillary premolars were used. The discs were then infected with Streptococcus mutans suspension and randomly divided into the following 6 groups according to the dentin treatments: the negative control group: noninfected sound dentin discs, the positive control group: infected discs were left untreated; the NaOCl group: treated with 5% NaOCl solution, the chlorhexidine (CHX) group: 2% CHX solution, the Carisolv group: Cadsolv gel (Medi Team Dentalutveckling AB, Savedalen, Sweden), and the Papacarie group: Papacarie gel (Formula & Acao, Sao Paulo, Brazil). All the agents were applied for 5 minutes. The dentin discs were fractured into 2 halves and stained with fluorescent LIVE/DEAD Stain (Molecular Probes, Eugene, OR). Each specimen was observed using confocal laser scanning microscopy at 5 different randomly selected sites. Results: The results of 1-way analysis of variance revealed that 5% NaOCl solution achieved the highest intratubular antibacterial effect, whereas Carisolv gel had the lowest antibacterial effect (P < .05). No significant difference in antibacterial effect was observed between the Papacarie gel and 2% CHX solution (P > .05). Conclusions: The enzyme-based chemomechanical caries removal (Papacane) was effective in the reduction of residual cariogenic bacteria in the dentinal tubules of coronal dentin.