Histomorphometric and microbiological assessment of photodynamic therapy as an adjuvant treatment for periodontitis: a short-term evaluation of inflammatory periodontal conditions and bacterial reduction in a rat model.

OBJECTIVE: The aim of this study was to investigate the short-term effects of photodynamic therapy (PDT) in periodontal tissue when it is used as an adjuvant treatment for periodontitis. BACKGROUND DATA: PDT has been used as an adjuvant in the combat of local infections, such as periodontitis, and combines a photosensitizer (PS) with a light source to induce reactive oxygen species (ROS) and kill microbial cells. METHODS: Fifty healthy male rats were used in this study. Periodontitis was induced by placing a cotton ligature around the upper left second molar in a subgingival position. Posterior maxillas were removed and histologically prepared with hematoxylin & eosin (H&E) staining techniques. PDT was performed with a diode laser (λ=660 nm) with an output power of 100 mW. Methylene blue aqueous solution (100 µM) was used as the PS while control group used phosphate buffered saline (PBS). Collagen organization, inflammatory infiltrate, and bone loss were evaluated. Bacterial samples were collected before and immediately after treatment to determine bacterial reduction. RESULTS: The experimental group that was treated with PDT presented better periodontal healing, as measured by collagen organization, inflammatory infiltrate, and bone loss. Significant bacterial reduction was achieved following treatment with or without PDT compared to control, with a higher microbial reduction observed in the PDT group. CONCLUSIONS: PDT used as an adjuvant treatment showed effective short-term control of periodontitis infection.

Comparative study between the effects of photodynamic therapy and conventional therapy on microbial reduction in ligature-induced peri-implantitis in dogs.

BACKGROUND: Progressive peri-implant bone losses, which are accompanied by inflammatory lesions in the soft tissues, are referred to as peri-implantitis. The aim of this study was to compare the effects of photodynamic therapy (PDT) and conventional technique on microbial reduction in ligature-induced peri-implantitis in dogs. METHODS: Eighteen third premolars from nine Labrador retriever dogs were extracted and the implants were submerged. After osseointegration, peri-implantitis was induced. After 4 months, ligature was removed and natural bacterial plaque was allowed to form for another 4 months. The animals were then randomly divided into two groups. In the conventional group, they were treated using mucoperiosteal flaps for scaling the implant surface and chlorexidine (conventional) irrigation. In the PDT group, only mucoperiosteal scaling was carried out before photodynamic therapy. Inside the peri-implant pocket, a paste-based azulene photosensitizer was placed and then a GaAlAs low-power laser (lambda=660 nm, P=40 mW, E=7.2 J for 3 minutes) was used. Microbiological samples were obtained before and immediately after treatment. Before treatment, one implant was removed and analyzed by scanning electron microscopy to validate the contamination. RESULTS: The results of this study showed that Prevotella sp., Fusobacterium sp., and S. Beta-haemolyticus were significantly reduced for both groups. After treatment, no significant differences were observed between the groups. CONCLUSION: These findings suggest that photodynamic therapy is a non-invasive method that could be used to reduce microorganisms in peri-implantitis.