Accuracy and Efficiency of 4 Guided Techniques for Calcified Canal Access: An In Vitro Study with a Novel 3D-printed Model.

INTRODUCTION

Pulp canal calcification (PCC) remains a significant clinical challenge in root canal treatment. This in vitro study used a self-designed reusable 3D-printed calcified root canal model to evaluate the accuracy and efficiency of four PCC access preparation methods: freehand, static navigation, dynamic navigation, and robot-assisted (RA) navigation.

METHODS

The study utilized a self-designed 3D-printed model that simulates the clinical characteristics of PCC and achieves precise positioning. A total of 192 resin models were used, and 4 cavity preparation methods were performed by specialists and inexperienced operators on maxillary and mandibular models, respectively. Using 3D reconstruction technology, the differences in offset angle, operation time, and tooth tissue loss among the groups were compared.

RESULTS

A reusable, standardized PCC model was successfully fabricated. Significant differences were observed among the four methods (P < .05). RA demonstrated the best overall performance, with an angular deviation of 1.31 ± 0.32°, an operation time of 12 ± 2 s, and a tooth substance loss of 9.03 ± 0.57 mm3, followed by the static navigation group, while freehand was the poorest performer. RA significantly narrowed the experience gap among operators, enabling novice operators to reach the expert level (P < .05) and compensated for mandibular anatomical difficulties, ensuring consistent accuracy between maxillary and mandibular models (P < .05).

CONCLUSIONS

The self-designed PCC model has excellent wear resistance and reusability, and the RA-centered digital system advances endodontic treatment toward precision, minimal invasiveness, and standardization. It provides a promising clinical option for PCC management.