Técnicas de remoção de retentores intrarradiculares: um estudo in vitro

Abstract

Considering t e use of intrarradicular anchorage, the removal of retainers is rarely required. However, the best technique for removing intraradicular retainers considering pin type, time require, cost an wear of the health dental tissue is still unknown. Thus, the objective of this study was to perform a randomized in vitro study to determine the best removal tecnique for intraradicular retainrs (glass fiber pin or molten metal core) from the use of ultrasound, drill, or the combination of both. Endodonticall treated niradicular teeth re randomized according to the type of pin (glass fiber or moltn metal core). The pins wer cemented with self-adhesive resin cement. For the fiberglass pins were made cores in composite resin. Sixty teeth were divided into six gr ups (n = 10), the fi st three groups received fiberglass pins and were evaluated according to the removal technique ultrasound, drill or association of techniques) and the last 3 groups received nuclei and were evaluated in the same way with respect to the removal. For each techniqu cost and wear of healthy tooth structure was timed. For the eval timing for removal, ation of the time the accounting was performed from the beginning of the technique until the complete removal or fracture of the tooth / pin. The cost was based on the value for each removal technique, con idering products of continuous use, ultrasonic tips, diamond tips, broad drill and clinical hours of the professional. Standardized periapical radiographs were performed to assess the wear of the healthy structure after root canal abruption, and immediately after the removal of the pins the radiographs were repeated to obtain the percental e of loss of the estimated dental structure. No statistical analysis was performed for the cost. To analyze the time required to remove the retainers, a variance analysis w s performed at one criterion, and paired t-test was performed to analyze the dental structure loss. The level of significance was 5%. There was n statistic lly significant difference for the time required to remove the pins between groups (p <0.05). However, on average, the group that received molten metal ore and sed the drill technique required more time for its removal (5.53 min). The group that received the same type of pin and was removed with ultrasound took less time (4.53 min) For the assessment of loss of tooth structure, there was a statistically significant differenc for all groups considering the loss within the same group, with the fiberglas pin and drill remo al groups showing a greater loss f structure (36.9 %) and the group with molten metal nucleus and ultrasound sh wed less loss (10.2%). It is concluded that the technique th t provides less loss of d ntal structure (ultrasound) seems to be the best option for removal of intra-radicular pins. Regarding the cost and time required for removal, furt er studies should be performed, although it can be stated that the highe t average cost was ass ciated technique (R $ 11.19).