Confocal scanner laser evaluation of bactericidal effect of different antibiotic mixtures used for dental pulp regeneration: a preliminary study

Abstract Aim Evaluate the antibacterial efficacy and depth of action into dentinal tubules of different antibiotic mixtures used for dental pulp regeneration (1-9). Methodology Cylindrical specimens of radicular dentine (n = 72), sterilized with ethylene oxide, have been infected with Enterococcus Faecalis (3 × 10 7  CFU/mL) for 3 weeks (10). Specimens were randomly assigned to 3 experimental groups (n = 20) plus positive (n = 6) and negative (n = 6) controls. • TRIMIX group (ciprofloxacin, metronidazole and minocycline) • BIMIX group (ciprofloxacin and metronidazole) • TRICLARITRO group (ciprofloxacin, metronidazole and clarithromycin) Each experimental group was divided in two subgroups exposed to antibiotic paste formulations added to macrogol (MG) or ialuronic acid (HA). After 3 weeks o exposition to antibiotic formulations, all specimens were vertically fractured and analyzed with confocal laser scanning microscopy (CLSM) and viability staining (Live/Dead BacLight Viability Stain) to quantitatively evaluate the ratio of dead/live bacteria into dentine tubules (11-12). Volume ratio of red fluorescence (Dead bacteria) was calculated in three-dimensional reconstructions. Differences among groups were analyzed with Kruskall-Wallis and post-hoc Dunn's test ( P P Results No significant differences regarding bactericidal effect between TRIMIX and TRICLARITRO were reported ( P  > 0,05). All antibiotic mixtures conveyed by HA showed a better efficacy compared with MG ( P TRIMIX penetration mean was higher than TRICLARITRO and BIMIX ( P P  > 0,05). Conclusions TRICLARITRO antibiotic mixture showed an effective antibacterial action deep into dentinal tubules, without the risk of tooth crown staining (10).