Long-term Outcome in a Patient with Discrepancy between Dental and Mandible Midlines

Abstract

The primary objective of surgical orthodontic treatment is to achieve occlusal function of the stomatognathic system. However, high esthetic demands have recently presented treatment providers with an additional challenge in carrying out such treatment, and occlusal function and esthetic considerations need to be balanced. Establishing the optimal treatment goal is the most critical factor in achieving high-quality results in surgical orthodontic treatment. Three-dimensional computed tomography (3-D CT) provides detailed information on maxillofacial deformation and the spatial relationship between cranial and dental structures. The use of 3-D CT in orthognathic surgery is now widespread thanks to rapid development of computers in the field of dentistry. In this case report, the patient had a discrepancy in the midline between the mandibular dentition and body. While 2-D information could be obtained by the standard cephalometric analysis, it would not have been possible to obtain 3-D morphological information. However, with 3-D CT it was possible to determine the midline discrepancy between the mandibular dentition and body. In treatment planning, 3-D CT analysis indicated that the midline of the mandibular dentition should be established between the left central incisor and the left lateral incisor, as the mandibular body midline coincided with the left central incisor and left lateral incisor in the mandibular dentition.
Presurgical orthodontic treatment and orthognathic surgery were performed according to the treatment objectives based on information obtained by 3-D CT analysis. A harmonized facial appearance in both the lateral and frontal views was accomplished. Not only intimated interdigitation but also improvement of occlusal function, namely lateral guidance and chewing movement, was observed. Thus, 3-D CT allowed the critical points in the special relationship between the various cranio-facial structures and the precise goal of surgical orthodontic treatment to be established. This case demonstrated that 3-D CT is a useful tool in diagnosis and planning not only in surgical simulation, but also in establishing pre-orthodontic treatment goals.