Predictors Of Root Canal Treatment Outcomes: A Randomized Trial

This randomized prospective clinical trial aimed to identify predictors of treatment outcomes following root canal treatment using either a conventional (CP) or minimally invasive protocol (MP), with particular attention to the extent of root canal preparation. A total of 176 mature permanent teeth requiring primary endodontic treatment were randomly assigned to the CP or MP groups. The CP group received ProTaper Gold instrumentation and the continuous wave condensation technique, while the MP group was treated using TruNatomy files, ultrasonic-assisted irrigation, calcium hydroxide medication, and a sealer-based obturation technique. Clinical and radiographic evaluations were conducted after a minimum 2-year follow-up period to determine healing outcomes. Of the initial sample, 125 teeth were recalled, with a mean follow-up of 35 months and a recall rate of 71.4%. Multivariable logistic regression identified the MP group and presence of a sinus tract as consistent predictors of treatment failure across both success criteria. Additionally, male sex and absence of sealer extrusion were associated with failure in only one of the two models and should be interpreted with caution. These findings suggest that while minimally invasive protocols may preserve more dentin, their effectiveness may be compromised if adequate disinfection is not ensured. Clinicians should consider both procedural and preoperative variables—particularly clinical signs such as a sinus tract—when selecting an appropriate treatment protocol. A balanced approach between dentin preservation and disinfection remains essential for predictable healing outcomes in endodontic treatment.