Effect of treatment frequency on the efficacy of superhydrophobic antimicrobial photodynamic therapy of periodontitis in a wistar rat model.

Superhydrophobic antimicrobial photodynamic therapy (SH‐aPDT) is advantageous wherein airborne singlet oxygen (1O2) is delivered from a device tip to kill a biofilm with no photosensitizer exposure and no bacterial selectivity (Gram + or Gram −). For effective treatment of periodontitis, the frequency of treatment as well as the optical light fluence required is not known. Thus, we sought to determine whether single or repeated SH‐aPDT treatments would work best in vivo using two fluence values: 60 and 125 J/cm2. We assessed the efficacy of three protocols: single treatment; interval treatments (days 0, 2, and 7); and consecutive treatments (days 0, 1, and 2). After 30 days of evaluation, we found that, SH‐aPDT in 3 consecutive treatments significantly decreased Porphyromonas gingivalis levels compared to single and interval SH‐aPDT treatments, as well as SRP‐chlorhexidine (CHX) controls (p < 0.05). Notably, clinical parameters also improved (p < 0.05), and histological and stereometric analyses revealed that consecutive SH‐aPDT treatments were the most effective for promoting healing and reducing inflammation. Our study shows what works best for SH‐aPDT, while also demonstrating SH‐aPDT advantages to treatment of periodontitis including no bacterial selectivity (Gram + or Gram −) and preventing the development of bacterial resistance. [ABSTRACT FROM AUTHOR]