Post Removal: Influence of Coronary Shape and Ultrasonic Device Use

Objective: The aim of the study was to evaluate the influence of the post coronary shapes on the removal of cemented metallic posts using an ultrasonic device. Methods: Twenty four bovine incisors were selected, endodontically obturated and the silver cast posts were cemented with zinc phosphate cement. The teeth were randomly divided in two groups (n = 12): Group I: posts were confectioned without the anatomical reproduction of the coronary portion, and Group II: the posts were confectioned with anatomical reproduction of the coronary portion. Both groups were submitted to ultrasonic vibration in two cycles of three minutes (US). The required force to remove the posts was determined using a tensile test on a mechanical testing machine (EMIC DL-2000), with a crosshead speed of 0.5mm/minute. In the second part of this study, the posts were again cemented and did not receive ultrasonic vibration (C) before tensile test.Data were submitted to ANOVA and Tukey test (p<0.05). Results: The results were (kgf): GIC (49.85±11.10)A; GIIC (48.22±11.09)A; GIIUS (32.36±6.21)B and GIUS (8.00±7.52)C. Conclusion: It can be concluded that the design of the post without the anatomical reproduction of the coronary portion facilitates its removal only when associated to the ultrasonic device usage.