Evaluation of antimicrobial photodynamic therapy (aPDT) effects using zinc tetracarboxy-phthalocyanine N-methylglucamine salt photosensitizer as an adjunct therapy in the treatment of induced periodontal disease in rats

Abstract

Antimicrobial photodynamic therapy (PDT) is a minimally invasive method consisting in the application of a photosensitive dye, which is subsequently stimulated by a light source and reacts with oxygen, producing reactive species. The aim of the present study was to evaluate in vivo tissue responses to PDT using zinc tetracarboxy-phthalocyanine N-methylglucamine salt (ZnTcPc-G)—10 μg/mL and red LED light (655 nm) in the treatment of induced periodontal disease (PD) in rats, through microtomographic, histometric, and histological evaluations. Ligatures were placed into the sulcus of the second maxillary molars for PD induction. The animals were divided into four groups: PD (disease induction, without treatment); SRP (induction and basic periodontal treatment); PDT (induction and application of photodynamic therapy); SRP + PDT (induction, application of photodynamic therapy, and basic periodontal treatment). The ligatures were removed after 15 days, and treatments were performed the following day. The animals were euthanized after 7 and 30 days of treatment. As all data were normally distributed (Kolmogorov-Smirnov), the parametric ANOVA test was applied, followed by Tukey test. Concerning histometry data, no statistical differences were observed between groups. The microtomographic analysis indicated significant differences in the two periods for the PD and SRP + PDT groups and, at 7 days, for the PD and PDT groups in the furcation area. No significant differences were observed in the interproximal regions. Regarding the histological analyses, no tissue damage was observed. These data indicate that PDT using ZnTcPc-G was not effective in reducing bone loss in PD induced in rats, although further studies are required to further elucidate PDT effects.