Surgical - orthodontic planning of complex cases through the use of 3D models: A case report

Abstract

Stereolithographic models are three-dimensional reproductions of digital data, created using CAD-CAM software. In recent years, the use of these three-dimensional models has increased as an aid in orthodontic diagnostics and in the planning of oral and maxillofacial surgery [1]. Unlike conventional diagnostic imaging techniques, such as Orthopanoramic radiographs and Cone-Beam CT (CBCT), which provide valuable digital information on bone size and geometry, stereolithographic models exhibit a physical three-dimensional reproduction of the anatomical area of interest with maximum accuracy. These truly guide both the diagnosis process and the surgical operation itself, in order to improve preoperative planning and minimize operative and postoperative morbidity. For the reproduction of these models, a CBCT scan is necessary. Through a 3D printing software, the data is converted into a stereolithographic model in scale. It is produced with transparent resin for better visualization of the bone structures and internal anatomical structures involved, such as the path of the inferior alveolar nerve or, as in this case report, the presence of dental elements totally impacted in the bone [2,3]. The use of these three-dimensional models has demonstrated a series of advantages such as a more accurate planning both orthodontic and surgical treatment, a significant reduction of operating times, a reduction in the time of exposure of the wound, better communication with colleagues and patients and more predictable surgical results [1]. Toothimpaction is defined as the failed eruption of a tooth, which remains embedded in the maxillary or mandibular bone after its period of physiological eruption. It can be partial or total and it most commonly happensto third molars, especially mandibular wisdom teeth, followed by the maxillary canines. Unlike the third molars, the maxillary canines constitute dental elements of great functional importance. They play agreat role of control in the movements of mandibular excursion. According to the classification of included maxillary canines by Yamamoto et al. there are 7 types (Figure 1), with the first three types showing more predictable results in the surgical orthodontic treatment and the following four types considered untreatable with orthodontic anchorage [4].