González-Colmenares Gretel, Calvo-Díaz Liliana, Nastul-Enríquez Marcela, Bertel-Ruíz María Mónica, Garzón-Ramírez Ingrid, Rojas-Sánchez Martha Patricia, Moreno-Gómez Freddy
Faculty of Dentistry, University Antonio Nariño, Career 3 E, No. 47A-15, Block 5, Bogotá, Colombia.
Postgraduate of Orthodontics, Faculty of Dentistry, University Antonio Nariño, Career 3 E, No. 47A-15, Block 1, Bogotá, Colombia.
Forensic Sci Int. 2020 Mar;308:110182. doi: 10.1016/j.forsciint.2020.110182. Epub 2020 Feb 6.
In cases of incineration, where the identification of victims by conventional methods is impossible, teeth and dental materials become an available source of evidence - thanks to their ability to resist high temperatures. Currently, there is no experimental research to determine the behavior of the bracket and the dental structure when it is attached to the tooth after being exposed to high temperatures. An experimental in vitro study was carried out on 60 upper and lower premolar teeth (30 with a cemented bracket and 30 teeth without a bracket) that were exposed to six temperature ranges (200 °C, 400 °C, 600 °C, 800 °C, 1000 °C and 1200 °C). With the help of an Optiks® binocular stereomicroscope, macroscopic changes were described for each temperature; in addition, the mesio-distal diameter of the crown of the teeth and the bracket were measured before and after the incineration. A comparison of the diameters between the groups [the experimental group and the control group] and between the different temperatures was made. Both teeth, with brackets and without brackets showed macroscopic changes, such as fissures, cracks, fragmentation, enamel bursting and enamel and dentin separation according to the temperature range exposed. The detachment of the bracket was presented at 600 °C - leaving a mark on the dental surface. At above 1000 °C, the crown of the tooth with bracket acquired a pink color and the surface of the bracket became rough and opaque. At above 400 °C, both groups experienced an expansion in the crown dimension without significant differences. The results of this research suggest that teeth with attached brackets are equally resistant as the teeth without brackets, and that the adhesion of these attachments to the dental structure leave characteristics that allow them to be differentiated from teeth without braces -as well as suggesting the orientation to the temperature exposure.
在焚烧案件中，若无法通过传统方法识别受害者，牙齿及牙科材料便成为了可用的证据来源——这得益于它们抵抗高温的能力。目前，尚无实验研究来确定高温暴露后，托槽与牙齿结构相连时的行为表现。本研究在体外对60颗上下颌前磨牙进行了实验（30颗粘结有托槽，30颗未粘结托槽），将其暴露于六个温度范围（200℃、400℃、600℃、800℃、1000℃和1200℃）。借助Optiks®双目立体显微镜，描述了每个温度下的宏观变化；此外，还测量了焚烧前后牙齿冠部及托槽的近远中直径。对各温度组间（实验组和对照组）以及不同温度间的直径进行了比较。无论有无托槽，牙齿均呈现出宏观变化，如根据暴露温度范围出现裂隙、裂纹、破碎、釉质爆裂以及釉质与牙本质分离。托槽在600℃时出现脱落——在牙齿表面留下痕迹。温度高于1000℃时，粘结有托槽的牙齿冠部变为粉红色，托槽表面变得粗糙且不透明。温度高于400℃时，两组牙齿冠部尺寸均有增大，且无显著差异。本研究结果表明，粘结有托槽的牙齿与未粘结托槽的牙齿具有同等的耐受性，这些附件与牙齿结构的粘结留下了一些特征，使得它们能够与未佩戴矫治器的牙齿区分开来——同时也表明了温度暴露的方向。
