Antimicrobial photodynamic therapy combined to periodontal treatment: Experimental model

Antimicrobial photodynamic therapy (aPDT) has been used as an adjuvant treatment for periodontitis. It combines a photosensitizer with a light source to induce reactive oxygen species and kill microbial cells. PpNetNI is a protoporphyrin derivative, and it has a chemical binding site at biofilm and great affinity to microbial cells. The aim of this study was to investigate the effects of aPDT as an adjuvant treatment for periodontitis.

Thirty healthy male rats Wistar (Rattus norvegicus) were used in this study (Approved by UNINOVE Ethical committee AN0029/2015). Periodontitis was induced by placing a cotton ligature around the first mandibular molar in a subgengival position. The contralateral mandibular first molar received neither a ligature nor any treatment, and was used as a control. After 7 days, the ligature was removed and all animals received scaling and root planing (SRP) and were divided according to the following treatments: SRP group (received SRP and irrigation with PpNetNI, 10μM) and aPDT group (PpNetNI 10μM followed by LED irradiation). aPDT was performed with a LED (630nm) with an output power of 400mW (fluence-rate 200mW/cm²; fluence 18J/cm²). Rats were euthanized at 24h, 48h and 7days postoperatively. The area of bone loss in vestibular region of the first molar was evaluated by Optical Coherence Tomography (OCT, THORLABS LTD., Ely, UK). Data were analyzed statistically (ANOVA and Tukey tests, p<0.05).

The animals treated by aPDT showed bone gain of approximately 30% compared to the SRP group following 7days from the treatment.

aPDT promoted bone recovery 7days after periodontal intervention.