Date of Award

2020

Document Type

Thesis

Degree Name

Master of Science in Dentistry

College

College of Dental Medicine

First Advisor

Theodore D. Ravenel V

Second Advisor

Robert P. Bethea

Third Advisor

Zachary Evans

Abstract

Introduction: Retreatment of root canals often involves removal of obstructions. Commonplace are fiber posts that have been placed that require drilling of the post to gain access to the root canal system. Guided endodontic procedures, and more specifically Dynamic Guidance is an emerging field in dentistry. Objective: To determine whether dynamic navigation instrumentation is more accurate and more efficient at bonded fiber post removal than free-hand removal. Materials and Methods: Thirty maxillary incisors were treated endodontically using the ProTaper Gold system and obturated with warm vertical compaction. Post space was prepared and size 2 fiber posts were bonded into the canals. Teeth were mounted in acrylic arch forms. Preoperative CBCT scans were taken and imported into the X-Guide system. Using the X-Guide software, drill trajectories and depths were planned for the removal of the posts for all 30 teeth. The teeth were randomly divided into two groups of 15. In group 1, the posts were removed using the X-Guide system by a second year endodontic resident. In group 2, the posts were removed “freehand” by an experienced endodontist (17+ years of experience). The time to remove the posts was recorded for both groups. Repeated measures analysis of variance models (ANOVA) were run for each outcome. The times to perform the procedure were compared for each group, a repeated measures ANOVA was run to compare groups. Post-operative CBCT images were taken and all teeth were analyzed for accuracy of the depth and trajectory of the performed drill path and compared to the depth and trajectory planned by the X-Guide software. Repeated measures analysis of variance models (ANOVA) were run for each outcome. Results: The times comparing Group 1 (X-Guide) with Group 2 (Freehand) are depicted in Tables 1a and b. The mean time for post removal for Group 1 was 38.6 seconds (± 16.12) which was significantly lower (pvalue 0.0006) than for Group 2, which was 524 seconds (± 430.56). The average angular deviation for Group 1 and Group 2 was 1.13 degrees (±0.47) and 3.16 degrees (±1.71) respectively, and the difference was significant (p-value 0.0004) . The average non-depth deviation at the access site on the occlusal surface was 0.365 mm (±0.14mm) for Group 1 and 0.621 mm (±0.27) for Group 2, the difference was significant (p-value 0.004). The average apical non-depth deviation at the apical extent of the drill path for Group 1 was 0.298 mm (±0.14mm) and for Group 2 was 0.381mm (±0.32), the difference was not significant. The average apical depth deviation at the apical extent of the drill trajectory was -0.1295mm (±1.11mm) for Group 1 and 1.026 mm (±1.29) for Group 2, the difference was significant (p-value 0.004 Conclusions: Using a Dynamic Guidance system to remove bonded endodontic fiber posts is both quicker and more accurate than free-hand removal.

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