The evaluation of the technical quality of root canal fillings performed by preclinical students on extracted teeth

The aim of this study was to evaluate the technical quality of root canal fillings performed by undergraduate preclinical students and to interpret the findings according to tooth group and canal configuration. This retrospective observational study included 1,050 root canal fillings of extracted teeth performed by 120 third-year dental students between 2019 and 2021. Canal preparation was performed using a standardized manual step-back instrumentation protocol, and obturation was performed using cold lateral condensation with gutta-percha cones and resin-based sealer. Standardized digital periapical radiographs were used to assess treatment quality based on length, homogeneity, and taper criteria. A scoring system (0, 1, or 2) was used for statistical analysis, and inter-examiner agreement was assessed using the Kappa test. Overall, 692 of 1,050 root canal fillings (65.9%) were technically adequate. Adequacy was highest in mandibular premolars (82.6%) and lowest in mandibular molars (44.8%). The rate of adequate root canal fillings was significantly higher in single-rooted teeth than in multi-rooted teeth ( p < 0.05). Among the evaluated criteria, adequacy rates were 82.3% for length, 82.4% for taper, and 77.5% for homogeneity. The lowest adequacy rates for all three criteria were observed in mandibular molars. Most root canal fillings performed by preclinical students met the predefined technical adequacy criteria. Lower adequacy rates were observed in multi-rooted teeth, particularly mandibular molars. These findings should be interpreted within the limitations of a single-institution retrospective preclinical study.