Efeito do desgaste da ponta para preparo no espaço do pino de fibra de vidro

Abstract

Objective: To evaluate the effect of drill used for preparation in the space of the fiberglass post and to evaluate the effect of drill used for preparation. Method: 100 bovine incisors were randomly distributed in 5 groups, which had their crown removed leaving a root with 18mm and had to fulfill the pre-requisite of the canal to present a smaller diameter than the pin used in the study ø = 2.0 mm. They were then inserted into a plastic material with chemically activated acrylic resin and a material similar to the periodontal ligament was added. All underwent endodontic treatment. They were radiographed in a standardized way with a matrix so that an X-ray was made in the same position. The teeth were cleared using fiberglass doors and pins (White Post CD # 2, FGM, Joinville, SC, Brazil) according to the belonging group (15, 10, 15, 20). The time required for the preparation was analyzed and the new radiographic measurements for the comparison with the initial’s radiographs were made. As this was also analyzed in a scanning electron microscope. Results: The relation between the number of teeth prepared by the drill and the time required for the preparation allowed to obtain a formula capable of predicting the average preparation time as a function of the number of times the drill is used. The relation between the conduit area and the number of runs performed by the drill showed no significance. The drill observed in a scanning electron microscope demonstrated that a gradual increase in damage to the drill as the number of prepared teeth increased. Conclusion: Drills that perform a large number of preparations, take longer and generate less satisfactory preparations than when compared to the new drills.