Evaluating a Novel Visualization Device for Improving File Insertion Accuracy During Root Canal Treatment

This study aimed to evaluate whether adopting a horizontal viewpoint, facilitated by a novel digital assistive device, could enhance endodontic file placement accuracy and reduce operator-dependent variability during root canal treatment.A total of 40 modified upper jaw dental stone models, each accommodating a plastic tooth replacing the upper right second molar, were divided into two groups (n = 20 each). The mesiobuccal canal of each tooth was prepared to a standardized working length of 21.0 mm and a working width of size 35. A size 40 file with a stopper preadjusted to 19.0 mm was then inserted. In the first (conventional) group, files were placed without assistance; in the second (device-assisted) group, a horizontal-view digital device was designed, developed, and used to align and insert the file. The second operator, blinded to the device's purpose, performed all insertions under simulated clinical conditions. An intraoral scanner subsequently captured the vertical distance from the stopper's bottom surface to a standardized anatomical landmark. Pairwise comparisons between the two groups were computed using alignment software to account for potential measurement artifacts.Normality in both groups was confirmed via the Shapiro-Wilk test. An independent-samples t-test compared mean vertical distances. Additionally, differences in stopper positioning were calculated for all aligned virtual models in CloudCompare.The device-assisted group exhibited a significantly shorter mean stopper-to-landmark distance (0.425 mm, standard deviation [SD] = 0.225) than the conventional group (0.971 mm, SD = 0.432) (t = -5.014, p = 2.534 × 10^-5). Pairwise analysis highlighted closer apical positioning in the device-assisted group, closely matching pilot study findings that a 26.57° vertical viewing angle can distort perceptions by 0.5 mm. The device's mean intraoral mounting time was 224 s (SD = 35.2), considered negligible over the full treatment duration.Adopting a horizontal perspective with a novel digital assistive device significantly improved file placement accuracy and reduced operator-dependent variability during root canal treatment. Optimizing this device's design and assessing its cost-effectiveness may facilitate broader clinical adoption and further enhance endodontic procedural outcomes.