Optical profile: A key determinant of antibacterial efficacy of photodynamic therapy in dentistry

Photodynamic therapy in periodontitis: A narrative review

BACKGROUND

Periodontitis, a chronic infectious disease, is primarily caused by a dysbiotic microbiome, leading to the destruction of tooth-supporting tissues and tooth loss. Photodynamic therapy (PDT), which combines excitation light with photosensitizers (PS) and oxygen to produce antibacterial reactive oxygen species, is emerging as a promising adjuvant treatment for periodontitis.

METHODS

This review focuses on studies examining the antibacterial effects of PDT against periodontal pathogens. It also explores the impact of PDT on various aspects of periodontal health, including periodontal immune cells, human gingival fibroblasts, gingival collagen, inflammatory mediators, cytokines in the periodontium, vascular oxidative stress, vascular behavior, and alveolar bone health. Clinical trials assessing the types of PSs and light sources used in PDT, as well as its effects on clinical and immune factors in gingival sulcus fluid and the bacterial composition of dental plaque, are discussed.

RESULTS

The findings indicate that PDT is effective in reducing periodontal pathogens and improving markers of periodontal health. It has shown positive impacts on periodontal immune response, tissue integrity, and alveolar bone preservation. Clinical trials have demonstrated improvements in periodontal health and alterations in the microbial composition of dental plaque when PDT is used alongside conventional treatments.

CONCLUSIONS

PDT offers a promising adjunctive treatment for periodontitis, with benefits in bacterial reduction, tissue healing, and immune modulation. This article highlights the potential of PDT in periodontal therapy and emphasizes the need for further research to refine its clinical application and efficacy.

Optimization of Photobiomodulation Dose in Biological Tissue by Adjusting the Focal Point of Lens

The optical power density in biotissue is an important issue for photobiomodulation (PBM) clinical applications. In our previous study, the maximal dose and the power density distributions of 830 nm lasers under human skin could be exactly calculated and measured. In this work, the laser power density in tissue can be changed by adjusting the focal point of the lens. From the experimental results, it is evident that the power densities on the attached gingiva and the surrounding tissues can be improved. Thus, the dose of a near-infrared (NIR) laser in the target tissue can be increased with a suitable lens. Most importantly, focusing lasers on deeper tissue can avoid any damage to the skin. This study provides a dose optimization method on the target tissue, and the results can be applied to clinical applications, especially laser acupuncture (LA).