PBM’s effects on plaque microbiome for periodontal-orthodontic patients during retention

Abstract

<p>Abstract</p><p>Objectives: This study aimed to investigate the effects of photobiomodulation (PBM) therapy as an adjunct during the orthodontic retention phase in patients with periodontitis, employing 16S rRNA gene sequencing to analyze its impact on oral microorganisms.</p><p>Methods: Six patients with stabilized chronic periodontitis that planned to complete periodontal-orthodontic treatment were included in the study. Teeth on one side of the dental arch were randomly assigned to the PBM therapy group, receiving irradiation with a diode GaAlAs laser (940 nm), while teeth on the contralateral side were assigned to the placebo group, receiving sham irradiation. The illumination was applied monthly for 6 months after the end of orthodontic treatment. Supragingival and subgingival plaque samples were collected immediately after appliance removal (T0), and at 6 months (T1) and 12 months (T2) post-removal. 16S rRNA gene sequencing was used to compare supragingival (U) and subgingival (D) microorganisms between the PBM group (L) and the placebo group (P) at each time point.</p><p>Results: A total of 60 samples were collected, yielding a mean of 86,411 clean reads (SD=5,257). Alpha diversity analysis revealed no significant differences in species richness and evenness among groups (p>0.05). Beta diversity analysis focusing on unweighted and weighted UniFrac dissimilarity demonstrated differences in microbiota composition of supragingival and subgingival plaque between the PBM and placebo groups (P<0.05). Differential species analysis at the genus level indicated that Propionibacteriaceae and Micrococcaceae were enriched in the PDT0 group, Kingella was enriched in the PUT2 group, while Stomatobaculum and Moraxella were enriched in the LU group.</p><p>Conclusion: During the orthodontic retention period in patients with periodontitis, PBM-assisted therapy didn’t affect the richness and evenness of microbial species, but it did influence the microbiota composition and dominant species of supragingival and subgingival microorganisms. This impact showed no significant correlation with the duration of retention.</p>