Antimicrobial Photodynamic Therapy with Photosensitizer Improved the Gingival Collagen, Oxidative Status and Protect the Bone in Short Term Experimental Periodontitis

Abstract

Objectives: To evaluate the influence of antimicrobial photodynamic therapy (aPDT) with methylene blue (MB) dissolved in ethanol used as an adjunct to scaling and root planing (SRP) in periodontitis treatment on bone loss, collagen fibers and gingival oxidative status. Methods: Wistar rats were randomly randomized in five experimental groups according to the periodontal treatment: NC (negative control; no periodontitis); PC (positive control; periodontitis without any treatment); SRP (periodontitis and SRP), aPDT I (periodontitis and SRP+aPDT+MB solubilized in water), and aPDT II (periodontitis and SRP+aPDT+MB solubilized in ethanol 20%). To induce the experimental periodontitis, one mandibular right first molar of each animal received the cotton ligature in a submarginal position. The periodontal treatments were performed after 7 days of ligature removal. Results: PC group had more bone loss compared to the other groups. SRP and aPDT I groups showed equivalent bone losses and the aPDT II group showed bone loss similar to the aPDT I group, smaller than the PC and SRP groups on the 7th day. PC and SRP groups showed higher gingival lipoperoxidation levels on the 7th day, but only the PC group exhibited higher gingival lipoperoxidation on the 15th day. Besides, it indicated an aPDT II protective action on the gingiva on the 7th day observed by the maintenance of the gingival glutathione (GSH) levels similar to NC group. The aPDT treatments were able to prevent gingival collagen degradation with 7 days of treatment. Conclusions: aPDT can act as a beneficial adjuvant tool to minimize bone loss, collagen degradation and periodontitis-induced oxidative damages. Therefore, it is possible to suggest that the short-term aPDT causes beneficial responses accelerating periodontal healing.