Dental-Plaque Decontamination around Dental Brackets Using Antimicrobial Photodynamic Therapy: An In Vitro Study.

Daliana-Emanuela Mocuta (Bojoga),Mariana Miron,Cornelia Muntean,Darinca Todea,Elena Hogea

doi:10.3390/ijerph182312847

Abstract

Background: In orthodontic therapy, the enamel around brackets is very susceptible to bacterial-plaque retention, which represents a risk factor for dental tissues. The aim of this study was to evaluate the effect of methylene blue and a chlorophyllin–phycocyanin mixture, used with and without light activation, in contrast with a 2% chlorhexidine solution, on Streptococcus mutans colonies. Methods: Twenty caries-free human extracted teeth were randomized into five groups. A Streptococcus mutans suspension was inoculated on teeth in groups B, C, D, and E (A was the positive-control group). Bacterial colonies from groups C, D, and E (B was the negative-control group) were subjected to photosensitizers and 2% chlorhexidine solution. For groups C and D, a combined therapy consisting of photosensitizer and light activation was performed. The Streptococcus mutans colonies were counted, and smears were examined with an optical microscope. Two methods of statistical analysis, unidirectional analysis of variance and the Tukey–Kramer test, were used to evaluate the results. Results: A statistically significant reduction in bacterial colonies was detected after the combined therapy was applied for groups C and D, but the most marked bacterial reduction was observed for group D, where a laser-activated chlorophyll–phycocyanin mixture was used. Conclusions: Photodynamic therapy in combination with methylene blue or chlorophyllin–phycocyanin mixture sensitizers induces a statistically significant decrease in the number of bacterial colonies.

Highlights

Streptococcus mutans (S. mutans), the most studied pathogenic microorganism of the oral cavity, is known as the main etiological agent of dental demineralization, which leads to dental caries
After a long period of the testing and reevaluation of several methods used to reduce pathogenic oral microorganisms, it can be stated that antimicrobial photodynamic therapy can be adopted as a modality for bacterial decontamination in dentistry [1]
This evaluation technique is in line with protocols reported in similar scientific studies, in which the antimicrobial photodynamic therapy (aPDT) method was used in association with bacteriological analysis [14,16,17,18]

Summary

Introduction

Streptococcus mutans (S. mutans), the most studied pathogenic microorganism of the oral cavity, is known as the main etiological agent of dental demineralization, which leads to dental caries. After a long period of the testing and reevaluation of several methods used to reduce pathogenic oral microorganisms, it can be stated that antimicrobial photodynamic therapy (aPDT) can be adopted as a modality for bacterial decontamination in dentistry [1]. APDT is a minimally invasive technique based on a combination of a photosensitizer activated by a light source with a specific wavelength to produce singlet oxygen, which inactivates the target oral bacteria [2]. The main applications of photodynamic therapy (PDT) in dentistry have focused on the diagnosis of malignant oral lesions, oral cancer therapy, and the inactivation of target oral bacteria.

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