Abstract
INTRODUCTION: Persistent endodontic infections often occur due to surviving or reintroduced microorganisms. Thus, effective disinfection is the key point for successful endodontic retreatment. Various advanced techniques have been invented to enhance the effectiveness of NaOCl, the standard irrigant. AIM: The aim of this study was to evaluate the use of photodynamic disinfection with light-emitting diode (LED) and lasers as adjuncts to sodium hypochlorite in endodontic nonsurgical retreatment cases. METHODOLOGY: Sixty-six symptomatic patients, aged 18-80 years requiring endodontic nonsurgical retreatment, were included. They were divided into three groups: Group ST (sodium hypochlorite), Group SD (LED activation), and Group SL (laser activation). Microbiological samples were collected pre- and postintervention. Microbiological analysis included aerobic/anaerobic cultures and polymerase chain reaction for uncultivable organisms. RESULTS: Group ST was most effective against Aggregatibacter actinomycetemcomitans and Prevotella intermedia (P = 0.005 and P = 0.004, respectively). All groups showed similar effectiveness against unculturable organisms and aerobic microorganisms. CONCLUSION: NaOCl is better than both LED and diode laser photoactivated disinfection (PAD) for endodontic retreatment, especially against A. actinomycetemcomitans and P. intermedia. In cases involving Olsenella uli, diode laser activation may be a suitable adjunct. While PAD methods contribute to microbial reduction, they do not surpass the efficacy of traditional NaOCl irrigation.