Treatment of experimental periodontal disease with antimicrobial photodynamic therapy in nicotine-modified rats

Background: The aim of this study was to compare antimicrobial photodynamic therapy (aPDT) as an adjunctive treatment to scaling and root planing (SRP) for induced periodontitis in nicotine-modified rats. Material & Methods: A total of 240 rats were evenly divided into two groups: C - saline solution treatment; N - nicotine treatment. Periodontal disease was induced in both groups at the first mandibular molar. After 7 days, the ligature was removed. All animals were submitted to SRP and were divided according to the following treatments: SRP - irrigation with saline solution; Toluidine Blue-O (TBO) - irrigation with phenothiazinium dye (100 mu g/ml); LLLT - laser irradiation (660 nm; 0.03 W; 4 J); and aPDT - TBO and laser irradiation. Ten animals in each group/treatment were euthanized at 7, 15 and 30 days. The histometric and immunohistochemical values were statistically analysed. Results: Intragroup analysis demonstrated that in both groups the aPDT treatment resulted in lower bone loss (BL) when compared to SRP in all experimental periods. Intergroup analysis demonstrated that aPDT treatment resulted in lower BL in Group N than in Group C treated with SRP in all experimental periods. Conclusion: Antimicrobial photodynamic therapy was an effective adjunctive treatment to SRP for induced periodontitis in nicotine-modified rats.