Evaluating the efficacy of cavity disinfection using methylene blue dye with 660-nm diode laser on primary molars: An in vivo study.

Background and objectives: The purpose of this study was to evaluate the antimicrobial activity of methylene blue dye with 660-nm diode laser in cavity disinfection and to compare the total bacterial count in dentinal samples preexcavation, postexcavation, and postdisinfection. The study design was experimental in vivo.

Materials and methods: Fifteen children aged 5-12 years with 15 primary molars requiring atraumatic restorative treatment (ART) were selected. Dentinal samples were collected from the carious tooth with a sterile spoon excavator three times, i.e., before caries excavation (preexcavation), after hand excavation of caries (postexcavation), and after doing laser photodynamic therapy with methylene blue dye and 660-nm diode laser (postdisinfection) and sent for microbiological analysis. The samples were transported in reduced transport fluid. The total bacterial count was carried out by an experienced microbiologist immediately after reporting.

Results: A significant number of bacteria was present after hand excavation of caries using ART. The bacterial count significantly reduced postlaser disinfection. The total viable bacterial count was reduced to 87.17% with hand excavation of caries, whereas it was reduced to 98.59% postlaser disinfection using methylene blue dye with 660-nm diode laser.

Conclusion: It was seen that ART cannot eliminate all the microorganisms. Methylene blue dye with a 660-nm diode laser was able to reduce the total bacterial count and can be effectively used as an antimicrobial cavity disinfectant.