Antimicrobial Photodynamic Therapy Combined with Photobiomodulation Therapy in Teeth with Asymptomatic Apical Periodontitis: A Case Series

Introduction: Apical periodontitis (AP) is an inflammatory disease of the periapical tissues that is often asymptomatic and diagnosed through radiographic examination. A challenge in traditional endodontics is disinfection of the root canal system (RCS), which anatomically presents numerous variations, often leading to persistent infections. Antimicrobial photodynamic therapy (aPDT) and photobiomodulation therapy (PBMT) offer promising adjuncts, due to their antimicrobial and tissue-healing properties. Objective: The aim of this article was to report five cases of teeth with pulp necrosis and asymptomatic apical periodontitis (AAP) treated with aPDT and PBMT protocols. Materials and Methods: Five cases of pulp necrosis and AAP were treated with conventional endodontic therapy supplemented with aPDT and PBMT. The treatment protocol included chemomechanical preparation (CMP), aPDT using a 660 nm diode laser (DL) with methylene blue (MB) as a photosensitizer (5 min pre-irradiation time), and PBMT using a 940 nm DL. Treatment results were evaluated through cone-beam computed tomography (CBCT)-based evaluation over 1 year of clinical follow-up. Results: All cases showed significant bone regeneration and tissue healing, demonstrating the efficacy of the combination of aPDT and PBMT. Post-operative pain did not occur in any of the patients, suggesting a possible analgesic effect of PBMT. Conclusions: The combination of aPDT and PBMT in endodontic therapy promoted tissue recovery and improved the prognosis of AAP. Further research and randomized control trials are needed to optimize treatment protocols and evaluate the long-term effects.