Outcomes and Associated Prognostic Factors for Orthograde Canal Obturation Using Ortho MTA III : A Randomised Prospective Clinical Trial

Aim To prospectively compare treatment outcomes for orthograde canal obturation using Ortho MTA III (OMTA) with the continuous wave of compaction (CWC) using gutta‐percha (GP) and AH Plus sealer, and to identify associated predictive factors. Methodology Informed consent was obtained (110 patients), and single‐ or two‐rooted permanent teeth ( n = 120) diagnosed with pulp necrosis (or previously treated) and asymptomatic apical periodontitis or chronic apical abscess (periapical index, PAI ≥ 3) were randomly assigned to two groups ( n = 60/group). The canals were prepared to a minimal apical size #40 (ISO) based on their initial file size, disinfected and obturated by either CWC or OMTA using an enhanced disinfection protocol (GP disinfected, new gloves after each intraoperative radiograph and before starting obturation). Clinical and periapical radiographic examinations were conducted by two calibrated, independent endodontists during follow‐up periods of at least 12 months. Success rates and associated predictive factors (tooth‐, operator‐ and patient‐related) were analysed statistically using binary and multiple logistic regression ( p < 0.05). Results The median recall period was 30 months (14–48 months), and 104 teeth were finally analysed (recall rate: 86.67%). No significant differences in success rate were observed between the groups ( p > 0.05) under both loose (OMTA: 88.24%, CWC: 83.02%) and strict criteria (OMTA: 64.71%, CWC: 58.49%). Multivariate analysis revealed that age (OR = 5.735, 95% CI: 1.286–25.577, p = 0.022), periapical lesion size (OR = 6.596, 95% CI: 1.397–31.138, p = 0.017) and PAI score (OR = 2.081, 95% CI: 1.047–4.136, p = 0.036) were significant predictors of treatment failure. Conclusions Orthograde obturation of infected canals with Ortho MTA III demonstrated comparable success and treatment outcomes to those filled with GP and sealer by CWC, supporting its potential as a clinically viable alternative for the obturation of infected root canals. Trial Registration cris.nih.go.kr registration number: KCT00099939