Healing Outcomes Following the Treatment of Molars Using Different Root Canal Disinfection Methods: A Prospective Cohort Study

Abstract

Introduction: To address the shortage of clinical outcome studies on contemporary root canal disinfection methods, this prospective cohort study assessed healing of apical periodontitis (AP) after use of the GentleWave (GW) system or Ultrasonic Activation (UA) combined with negative pressure irrigation (NPI). Methods: Maxillary and mandibular molars with AP (n = 230) were treated with either GW or UA + NPI. A board-certified endodontist performed all procedures following standardized protocols. Patients with follow-up assessments available (n = 177) had radiographs assessed independently by 2 blinded endodontists who assigned a periapical index (PAI) score before and after treatment. The mean time between these assessments was 14.9 months. After excluding extractions, our statistical analyses first compared the numbers of positive and negative outcomes between GW (n = 85) and UA + NPI (n = 85) groups using strict (healed - PAI ≤2) and loose criteria (healing - decreased PAI >2). An ANOVA assessed if treatment type affected healing rates (PAI scores). Results: Following treatment and adopting the strict success criteria, 70.6% of cases in the GW group were successful, compared to 72.9% in the UA + NPI group. Under the loose criteria, 83.5% were successful in the GW group compared to 87.1% in the UA + NPI group. No significant differences were found between the groups adopting either criterion. There was also no effect of treatment type (GW vs UA + NPI) on healing rates (PAI scores). The follow up time after treatment did not impact these findings. Conclusions: Within the limitations of this study, the GW system and UA + NPI were equally effective in promoting AP healing, suggesting both methods are viable options for root canal disinfection. Further research is needed to optimize protocol strategies and improve clinical outcomes.