The Measurement Of Buccal Cortical Bone Thickness With Ct Images In Jaw Deformity Patients Undergoing Orthodontic Mini Implants

Background Recently, placement of orthodontic mini-implants (anchor screws) is widely used in orthodontic treatment. One of the anatomical factors affecting the stability of the anchor screws is the bone characteristics (shape, bone mineral density, cortical bone thickness). It is necessary to understand anatomical factors in the area of placement with preoperative diagnostic imaging.AimIn this study, we measured and evaluated the buccal cortical thickness of the mesio-distal interdental space at the mandibular first molar with multi-detector low computed tomography (MDCT) images of jaw deformity patients.Materials and MethodsMDCT images of 28 jaw deformity patients participating in the study were acquired and used for the preoperative planning of sagittal split ramus osteotomy (SSRO) surgery. All patients had been previously diagnosed as having an Angle class III malocclusion. After acquisition of MDCT data, all data were transferred to a workstation and evaluated using Zio Cube software. The standard plane of all MDCT data was set at the occlusal plane.The cortical thickness on the mesial and distal part of the first molar were measured on the reconstructed cross-sectional images at the level of 5 and 10 mm inferior to the cement-enamel junction (CEJ) on each mesial and distal side. On the same images, the inclination of the mandibular bone was also recorded. The MDCT images were excluded from this study if: (1) Pathological findings were seen in the posterior mandible; and (2) The images were found to exhibit insufficient image quality due to metal artifacts from acquisition or patient movement.ResultsInitially, all MDCT images were screened. From these, 5 were excluded according to the exclusion criteria. Thus, a total of 46 sides from 23 patients were used in the analysis. The 23 patients consisted of 15 females and 8 males with a mean age of 22.9 years (range from 18u201333 years). The average thickness at the 5 mm and 10 mm level form the CEJ on the mesial portion of the first molar were 1.44 mm and 1.91 mm respectively, and on the distal portion were 1.80 mm and 2.68 mm respectively. Statistical differences were confirmed for buccal cortical thickness at 5 mm and 10 mm from the CEJ in both the mesial and distal portions of the mandibular first molar. The average lingual inclination of the mandible was by 80.5u00b0 n the mesial and 71.2u00b0 in the posterior portion. ConclusionA detailed understanding of the anatomical characteristics is absolutely critical in maxillofacial surgical procedures, including the placement of anchor screws. To reduce postoperative discomfort, the clinician should be aware of each patientu2019s morphological characteristics.