The Comparison of the Effect of Photodynamic Therapy Using two Photosensitizer Indocyanine Green and Methylene Blue on the Colony Count of Staphylococcus Aureus (In Vitro)

Background and aim: Contamination of microorganisms, including Staphylococcus Aureus, in oral saliva and oral tissues, is a common problem. Therefore, in this study, photodynamic therapy's effect on the number of oral Staphylococcus Aureus colonies. Was evaluated using two indices of Indocyanine Green and Methylene Blue with sensitizer with Chlorhexidine mouthwash.
Materials and methods: In the first stage, a new culture of ATCC St.Aureus 25923 was performed. Colonies of Staphylococcus Aureus were counted. The teeth were randomly divided into four groups: the first group was Methylene Blue, and the second group was subjected to 2% Indocyanine Green. All samples from both groups were sampled before laser irradiation and colonized in the culture medium for 24 hours. The third group of teeth was immersed in 2% Chlorhexidine mouthwash and sampled. The fourth group was considered as the control group. Also, Post hoc analysis was used for comparing before and after treatment in each group.
Results: This study showed that all three experimental groups reduced the number of Staphylococcus Aureus colonies. However, Indocyanine Green and Methylene Blue did not significantly decrease the number of colonies before and after treatment (p> 0.05), but Chlorhexidine caused a significant decrease in the number of Staphylococcus colony Aureus (p <0.05).
Conclusion: The results of this study showed that all three groups of Chlorhexidine, Indocyanine Green and Methylene Blue, reduced the colony count of Staphylococcus Aureus, although the effects of the reduction of Staphylococcus Aureus were significantly more severe than Chlorhexidine.