Molecular Analysis of the Antibacterial Effects of Photodynamic Therapy in Endodontic Surgery: A Case Series

Abstract In this case series, bacterial reduction promoted by antimicrobial photodynamic therapy (PDT) used during endodontic surgery was evaluated. Cases were also followed up, and the surgical outcome was reported. The study consisted of 19 teeth with posttreatment apical periodontitis that were consecutively treated by endodontic surgery. After apicoectomy, the root end was treated with PDT using methylene blue as the photosensitizer. Bacteriologic samples were taken from both the cut root surface and the root-end cavity before and after PDT. Samples were analyzed for the total bacterial and Streptococcus group counts using quantitative real-time polymerase chain reaction. EndoSequence BC-RRM Putty (Brasseler, Savannah, GA) was used as the root-end filling. Patients were followed up, and the surgical outcome was evaluated. The reduction in bacterial counts after the PDT approach was analyzed using the nonparametric Wilcoxon signed rank test. PDT significantly reduced the total bacterial and streptococcal counts in both root-end cavities and resected root surfaces ( P