Impacto da técnica guiada versus ultrassom na dentina radicular após a remoção de pinos intrarradiculares: análise por micro-CT

Abstract

The removal of intraradicular posts is a clinical challenge due to the risk of excessive dentin removal, canal deviation, and even perforation. Therefore, this study aimed to compare guided and conventional techniques for the removal of glass fiber posts in extracted human mandibular incisors using micro-computed tomography (micro-CT). Eighteen extracted human mandibular incisors were selected through micro-CT and divided into two groups (n = 9): guided and conventional. The crowns were sectioned, and endodontic treatment was performed. Post spaces were prepared, preserving 5 mm of obturation material. The periodontal ligament and mandible were simulated, and the teeth were positioned in artificial mandibles in blocks of three. All blocks were scanned using cone-beam computed tomography (CBCT). In the guided group, an additional intraoral scan was performed to fabricate 3D acrylic guides for post removal. In the conventional group, posts were removed using an E3D ultrasonic tip coupled to an ENAC device under an operating microscope. The teeth were rescanned using micro-CT after post space preparation and post removal to assess whether the techniques reached the obturation material (gutta-percha), and to quantify canal volume, dentin removal, and the presence of dentinal microcracks. Data were analyzed using the Mann-Whitney or Student’s t-test, depending on data distribution (P < 0.05). Both techniques successfully reached the gutta-percha. The guided group required less time and promoted lower dentin removal (1.5%) compared to the conventional group (5.5%) (P < 0.05), but showed a greater amount of remaining post material, requiring supplementary removal using ultrasound, which resulted in three perforations and increased dentin removal (17.7%). The increase in microcracks was 4.1% in the conventional group, 15.1% in the guided group, and 17.81% after the additional ultrasonic intervention. In conclusion, both techniques were effective in reaching the obturation material. However, the guided technique proved to be more efficient, promoting less dentin removal, no canal perforation, and shorter working time, although it left more residual post material and resulted in a higher incidence of dentinal microcracks after post removal.