The effects of combined dynamic navigation system and dental operating microscope on the accuracy and efficiency of fiber post removal: an in vitro study.

Abstract

Background: There is limited information concerning the effectiveness of the combined dynamic navigation system (DNS) and dental operating microscope (DOM) technique in fiber post removal. The aim of this study was to assess the effectiveness of the DNS-DOM technique for fiber post removal compared with the freehand technique (FH)-DOM.

Methods: In a phantom head-based study, 30 human mandibular teeth were utilized, with 7 mm of fiber post left in obturated canals. Under a DOM, an experienced endodontist, employing an ET18D ultrasonic tip under a rubber dam, removed the fiber posts using either FH or DNS. Pre- and post-operative CBCT scans were taken, and 3D models were reconstructed with Materialise Mimics software. Accuracy (deviation volume, distance, angle, position) and efficiency (procedure time) parameters were analyzed. Normality was assessed with the Shapiro-Wilk test, utilizing the independent samples t-test for normally distributed data and the Mann-Whitney U test for non-normally distributed data.

Results: The DNS-DOM and FH-DOM groups demonstrated comparable results in deviation volume, percent deviation volume, maximum deviation distance, deviation angle, and maximum deviation position-all accuracy-related factors. We noted higher deviation and percent deviation volumes in DNS-DOM, which were not significant, compared with FH-DOM in incisors. Conversely, in molars, FH-DOM exhibited higher values than DNS-DOM, suggesting that the free-hand technique may result in less deviation under better visibility. There was a consistent trend of a higher deviation angle for DNS-DOM compared with FH-DOM across all tooth types. DNS-DOM and FH-DOM displayed a higher deviation angle in molars than in premolars and incisors. The distance between maximum deviation points and initial drilling points was smaller in molars compared with incisors and premolars. Regarding efficiency, the DNS-DOM group demonstrated a significantly longer procedure time (8 min) compared with FH-DOM. Fiber post removal time followed a similar trend in both groups, being fastest in molars, followed by premolars and incisors.

Conclusions: DNS-DOM showed accuracy comparable to FH-DOM in fiber post removal when performed by an experienced endodontist with appropriate ultrasonic tips. However, DNS-DOM had a longer procedure time, potentially reducing efficiency due to the additional navigation system integration, demanding increased operator operating time.