Evaluation of temperature rise and efficacy of cavity disinfection with diode laser: An in vivo study

BACKGROUND: Management of caries using minimally invasive dentistry is prevalent in dentistry today. A newer technology is to disinfect/sterilize caries in depth of the dental tissue with diode laser. However, to have a bactericidal effect, increased energy density of light amplification by stimulated emission of radiation (LASER) may be required which in turn may lead to higher thermal load causing harmful effects on vital pulpal tissue. AIMS: The aim was to evaluate temperature rise and efficacy of cavity disinfection with diode laser. MATERIALS AND METHODS: Twenty permanent molar teeth with dentinal caries were randomly assigned into two groups on the basis of LASER irradiation: Group 1 – at 1 W, Group 2 – at 2 W. The elevation of subsurface temperature during irradiation was measured using thermocouples positioned in the center of a prepared cavity. Dentinal samples were collected before and after disinfection of the cavity. These samples were subjected to microbiological evaluation for Streptococcus mutans on Mutans-Sanguis agar and Lactobacilli on Rogosa agar. STATISTICAL ANALYSIS: Log transformed “t”-test and paired “t“-test were used for the statistical analysis. RESULTS: Although the reduction in microbial count revealed insignificant difference at two different wattages, the rise in temperature with 1 W was less than that with 2 W. CONCLUSION: Efficacy of 1 W and 2 W is similar, but 1 W causes less thermal changes, thus, 1 W is recommended over 2 W.