RESUMO
BACKGROUND: The current study was devised with the objective of using a split-mouth, controlled clinical trial to compare conventional mechanical debridement (scaling and root planing) treatment (T1) with conventional mechanical treatment followed by photodynamic therapy (PDT) (T2) in patients with severe periodontitis. METHODS: Four PDT sessions were completed, and clinical parameters such as bleeding upon probing (BOP positive), plaque index (PI), probing pocket depth (PPD) and clinical attachment loss (CAL) were evaluated before and after the treatment series. In addition, gingival biopsies were collected at the start and finish of treatment, and were used for qPCR gene expression analysis of TNFA, IL1B, IL8, IL10, IL17, MMP13, FGF2, RANK, RANKL and OPG. RESULTS: The clinical results showed a significant improvement in BOP with treatment T2 (p=0.03). The molecular data showed an up-regulation of FGF2, RANK and OPG gene expression after T2. The expression levels of the other genes were not significantly different between T1 and T2. PDT increased the expression of RANK and OPG, which could indicate a reduction in osteoclastogenesis. Furthermore, the use of PDT in conjunction with conventional treatment significantly increased the expression of FGF2, which has an important role in the periodontal repair process. CONCLUSIONS: PDT technology could be a means to improve conventional periodontitis treatment. Our results suggest that PDT acts in part by controlling bone resorption and increasing the expression of genes important for tissue repair.