Comparison of Energy and Frequency of Nanosecond Q-Switched ND-YAG Laser and Chlorhexidine on Reducing the Number of Oral Streptococcus Mutans Isolates: In Vitro Study

Abstract

Background: Streptococcus mutans is a facultative anaerobic coccus that is a part of the oral flora of humans. chlorhexidine also has some side effects. Today, Nd: YAG lasers have become very popular in dentistry and are used for various types of treatment. Therefore, this study aims to compare the effects of Chlorhexidine 2% and nanosecond (Nd: YAG) laser in reducing the number of oral Streptococcus mutans bacteria in the oral cavity.
Materials and Method: Bacterial samples were tested using a 1064 nm Q-switched Nd:YAG laser with pulse energies of 10-20-30 mJ and frequencies of 5-10 Hz. Chlorhexidine's effect on S. mutans was tested using agar wells.
Results: The number of bacteria grown in 30 mJ energy was significantly less than the number of bacteria in 20 mJ energy, and the number of bacteria in 20 mJ energy was considerably less than the number of bacteria in 10 mJ energy Thus, it can be said that at each frequency level, by increasing the energy level to 30 millijoules, all oral S.mutans bacteria are destroyed. Also, no bacteria are observed if the energy level is reduced to 20 millijoules and the frequency is increased to 10 Hz. The highest number of bacteria was observed at energy level 10 and frequency 5.
Conclusion: The results showed the superiority of laser high-energy 1064 nm Q-switched laser output obtained by LD array end pumping Nd:YAG over chlorhexidine in eliminating S. mutans bacteria.