Comparative Evaluation of Antimicrobial Action of Photodynamic Disinfection, Dyes and Nanosilver against Streptococcus Mutans and Lactobacillus Acidophillus on Coronal Dentin: An In Vitro Study

1. Twenty four carious tooth were collected and screened for the isolation and identification of S.mutans and L.acidophillus. 2. The bacteria isolated were investigated for an experimental study of in-vitro antimicrobial photodynamic therapy effect in carious dentin slabs. 3. Silver nano particles in a concentration of 100μg/ml were prepared by borohydride reduction method and examined for different time of contact with the infected dentine. 4. The experiment was such that 60 slabs of occlusal human dentin were randomly assigned to six groups, exposed to a light emiting diode laser at 630 nm, and with a photosensitizer TBO-100μg/ml and also tested with Nanosilver particles and the combination of all the above antimicrobial treatments as follows: a. Group I - Negative control, b. Group II- Positive control, c. Group III-LED Laser Treatment, d. Group IV-LED Laser + TBO Dye Treatment. e. Group V -Nanosilver Treatment at different time intervals of 20, 40, 60, 80 seconds f. Group VI-Dye + Nanosilver + LED Treatment. 5. The slabs were subjected to a model for caries production with S.mutans and L.acidophilus inoculation in Brain heart infusion BHI broth. 6. After a 10 -day period of incubation, samples of carious dentin were collected before and after each treatment and cultured for streptococci mutans and Lactobacillus acidophillus. 7. The lighted groups were irradiated with energy density of 48J/cm2 obtained for about 60 seconds respectively.TB-O was applied for 5 minutes. 8. The samples of Group V were immersed in nanosilver solution for 20, 40, 60 and 80 seconds respectively and examined for streptococci and lactobacilli counts. 9. The data were analyzed statistically by ANOVA which showed a significant differences (p