Introduction: Owing to recent advancements in simulation software, it has become easy to perform three-dimensional simulation of tooth movement. However, a method for identifying the correct position of dentition in patients with various skeletal facial types has not been established. Therefore, this study aimed to define three types of occlusal curvature and compare the relationship between craniomaxillofacial morphology and the types of occlusal curvature at the time of initial examination.
Materials and Methods: We enrolled 24 patients with skeletal Class Ⅱ brachyfacial pattern, 20 with skeletal Class Ⅲ dolicofacial pattern, and 20 with skeletal Class Ⅰ mesiofacial pattern. Three occlusal curvatures obtained by cephalometric tracing were defined as follows: 1） loading occlusal curvature: the occlusal curvature obtained by connecting three points of strong occlusal contact; 2） mechanical occlusal curvature: the occlusal curvature obtained by connecting two points of strong occlusal contact and the top of the condyle; and 3） morphological occlusal curvature: the occlusal curvature approximating the buccal cusp of all mandibular teeth. We then compared these three occlusal curvatures with maxillofacial morphology, overjet, and overbite.
Results: In all three maxillofacial patterns, the center point of the mechanical occlusal curvature was located around the nasion. However, the radius of the mechanical occlusal curvature was significantly longer in patients with skeletal Class Ⅰ mesiofacial patterns than in patients with Class Ⅱ brachyfacial or Class Ⅲ dolicofacial skeletal patterns. In addition, there was a moderate negative correlation between the radius of the loading occlusal curvature and overjet in patients with skeletal Class Ⅰ mesiofacial patterns.
Conclusion: In all three maxillofacial patterns, an upward mechanical occlusal curvature was observed, and the center point was located around the nasion.

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A clinical survey was conducted on 1,180 cases of orthognathic surgery at Kyoto Oral Health Care Center, Rakuwakai Otowa Hospital from 2008 to 2022. The results were as follows:
1．The total number of patients was 1,180 cases for the last 14 years, and the average annual number was 84.4.
2．The male-female ratio was 1:2.8.
3．The mean age was 27.5 years old.
4．The most common clinical diagnosis was maxillary retrusion and mandibular protrusion, accounting for 276 cases.
5．The most frequently performed operation was the combination of Le Fort Ⅰ osteotomy （LF） and intraoral vertical ramus osteotomy （IVRO）, accounting for 297 cases, followed by the combination of LF and sagittal split ramus osteotomy （SSRO） at 241 cases.
6．The mean operation time and mean amount of bleeding were 286 minutes and 92g in LF＋IVRO, and 337 minutes and 133g in LF＋SSRO.
7．The number of cases of inferior alveolar nerve sensory disturbance after IVRO was less than that after SSRO or intraoral inverted L ramus osteotomy （ILRO）. The disorders by IVRO or ILRO were completely resolved within 1 year after surgery.
8．The mean duration of hospital stay was 7.5 days.
9．The number of referral clinics and hospitals from 2008 to 2022 was 53.

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