Comportamento forense de pinos odontológicos sob altas temperaturas: avaliações macroscópicas e imaginológicas

Abstract

To evaluate the physical behavior of intraradicular retainers subjected to high temperatures for forensic purposes. A total of 126 bovine teeth were selected. All teeth were endodontically treated and randomly assigned to six groups (n=21) according to the different materials: Exacto Angelus™ glass fiber post, Reforpost™ Angelus™ glass fiber post, Whitepost System DC FGM™ glass fiber post, Reforpost™ Angelus™ carbon fiber post, Reforpost™ I Angelus™ metal post, Ni-Cr metal post. Subsequently, each group was randomly divided into three subgroups (n=7), according to the ashing temperatures of 600, 800 and 1000 °C. All teeth were prepared and cemented according to their material. Micro-hybrid composite resin was used for coronal reconstruction. All teeth were photographed and radiographed in a standardized way before and after incineration. Macroscopically, the roots were assessed qualitatively after incision, in terms of the formation of cracks or root fractures, as well as color changes, using photographs. The radiographic evaluation considered qualitative aspects of the roots, such as the formation of cracks or root fractures, and aspects of the dental posts, such as internal adaptation, changes in dimension and/or shape, changes in radiopacity, the presence of radiolucent areas (“bubbles”), as well as the optical density of each material. Qualitative analyses of the optical density of the posts and dentin was assessed in periapical images using the ImageJ™. All images were analyzed by a single, previously trained evaluator in a dimly lit environment. Statistical analyses were carried out using a significance level of 5%. Macroscopically, there was no significant association between the temperature ranges and the formation of cracks or root fractures, as well as radiographically, with the exception of samples restored with Reforpost™ Angelus™ glass fiber. In terms of color, brown and gray were observed at 600°C, and white at 800°C and 1000°C. Radiographic analysis of the posts showed an association between the temperature ranges and the changes assessed, with the exception of the Angelus™ I Reforpost™ prefabricated metal post. At the pre- and post-incineration moments, there was a significant difference in the mean density of the posts of the materials: Angelus™ Reforpost™ glass fiber post, Whitepost System DC FGM™ glass fiber post, Angelus™ Reforpost™ carbon fiber post. The study concluded that the different materials do not interfere in the macroscopic changes presented by the root, however, the posts showed radiographic and radiopacity changes, depending on the material and temperature range evaluated. Therefore, the study provides important data for determining the changes in the different types of intraradicular posts, contributing to the process of human identification.