Micro-Computed Tomography of Tooth Volume Changes Following Post Removal
thesisposted on 27.02.2015, 00:00 by Jiyeon J. Kim
Hypothesis: A difference does not exist among various post and cement systems in the volumetric radicular dentin loss after a post is removed from an endodontically treated tooth. Purpose: The purpose of this study is to (1) compare change in dentin volume of endodontically treated teeth before and after removal of prefabricated post and cement systems, and (2) illustrate a microCT method for accurate dentin volume comparison among the teeth specimens. Methods: 48 extracted single root canal teeth were sectioned 13mm from the apex. Canal spaces were endodontically shaped. Preparations were filled with gutta-percha using lateral condensation. Post space was prepared, leaving 5mm of gutta-percha from the apex. Specimens were scanned with Micro CT to establish objective baseline volume and divided into two groups of post systems—stainless steel ParaPost (Coltene/Whaledent Inc.) and Glass-fiber reinforced composite post (Ivoclar Vivadent). Half of the posts for each group were cemented with Ketac Cem radiopaque glass-ionomer cement (3M ESPE) and the other half with SpeedCEM dual-curing resin cement (Ivoclar Vivadent). The posts and residual cement were removed using an ultrasonic device and endodontic operating microscope. The remaining tooth root structure was scanned again using micro CT with volume reported (mm3). The statistical difference between the combination of posts and cements was measured using Kruskal-Wallis ANOVA test (α = 0.05). The independent groups are evaluated separately using post-hoc examination to determine which ones resulted in the statistically significant difference. Results: Change in mean volume was 81.3%, 42.2%, 25.4%, 35.0% for group 1-4. Kruskal Wallace ANOVA (p<0.05) rejects null hypothesis and Post Hoc test reveals statistically significant difference (p<0.001) between group 1 and the other groups. Conclusion: MicroCT can be used to accurately assess dentin volume change. Serrated parallel-sided SS posts with GI cement had significantly more tooth structure loss upon post removal compared to other combination of post and cement systems. This may be contributed to the mechanical retention of serrated parallel sided posts and the adhesive retention of GI cement to the root dentinal surface.