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

Abstract

AimEvaluate the antibacterial efficacy and depth of action into dentinal tubules of different antibiotic mixtures used for dental pulp regeneration (1-9). MethodologyCylindrical specimens of radicular dentine (n=72), sterilized with ethylene oxide, have been infected with Enterococcus Faecalis (3×107CFU/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<0,05). Mean penetration depth of action was recorded and differences were analyzed with one-way ANOVA and post-hoc Bonferroni's test (P<0,05). ResultsNo 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<0,05).TRIMIX penetration mean was higher than TRICLARITRO and BIMIX (P<0,05), but there were no differences between HA and MG sub-groups (P>0,05). ConclusionsTRICLARITRO antibiotic mixture showed an effective antibacterial action deep into dentinal tubules, without the risk of tooth crown staining (10).