OBJECTIVE: To establish a similarity measurement model for patients with dentofacial deformity based on 3D craniofacial features and to validate the similarity results with quantifying subjective expert scoring. METHODS: In the study, 52 cases of patients with skeletal Class Ⅲ malocclusions who underwent bimaxillary surgery and preoperative orthodontic treatment at Peking University School and Hospital of Stomatology from January 2020 to December 2022, including 26 males and 26 females, were selected and divided into 2 groups by sex. One patient in each group was randomly selected as a reference sample, and the others were set as test samples. Three senior surgeons rated the similarity scores between the test samples and the reference sample. Similarity scores ranged from 1 to 10, where 1 was completely different, and 10 was exactly the same. Scores larger than 7.5 was considered as clinically similar. Preoperative cone beam computed tomography (CBCT) and 3D facial images of the patients were collected. The three-dimensional hard and soft tissue features, including distances, angles and 3D point cloud features were extracted. The similarity measurement model was then established to fit with the experts' similarity scoring by feature selection algorithm and linear regression model. To verify the reliability of the model, 14 new patients were selected and input to similarity measurement model for finding similar cases. The similarity scoring of these similar cases were rated by experts, and used to evaluate the reliability of the model. RESULTS: The similarity metric models indicated that the features of the middle and lower craniofacial features were the main features to influence the craniofacial similarity. The main features that were related to the expert' s similarity scoring included distance of anterior nasal spine-menton (ANS-Me), distance of right upper canion point-Frankfurt horizontal plane (U3RH), distance of left superior point of the condyle-left gonion (CoL-GoL), distance of left gonion-menton (CoL-Me), distance of pogonion-midsagittal plane (Pog-MSP), distance of right alar base-left alar base (AlR-AlL), angle of pronasale-soft tissue pogonion-labrale inferius (Pn-Pog' -Li), distance of trichion-right tragus (Tri-TraR), distance of left exocanthion-left alar base (ExL-AlL), lower 1/3 of skeletal face, middle and lower 2/3 of skeletal face and upper lip region of soft tissue. Fourteen new patients were chosen to evaluate the model. The similar cases selected by the model had an average experts' similarity scoring of 7.627± 0.711, which was not significantly different with 7.5. CONCLUSION The similarity measurement model established by this model could find the similar cases which highly matched experts' subjective similarity scoring. The study could be further used for similar cases retrieval in skeletal Ⅲ malocclusion patients.
Humans ; Male ; Female ; Imaging, Three-Dimensional/methods* ; Cone-Beam Computed Tomography ; Malocclusion, Angle Class III/surgery* ; Orthognathic Surgical Procedures/methods* ; Face/anatomy & histology* ; Cephalometry/methods* ; Adult ; Adolescent ; Dentofacial Deformities/surgery* ; Young Adult

OBJECTIVE: To evaluate the decompensation effectiveness and alveolar bone remodeling of mandibular anterior teeth after preoperative orthodontic treatment in high-angle patients with skeletal class Ⅱ malocclusion using lateral cephalogram and cone-beam computed tomography (CBCT). METHODS: Thirty high-angle patients with skeletal class Ⅱ malocclusion who had received preoperative orthodontic treatment and orthognathic surgery in Peking University School and Hospital of Stomatology between Ja-nuary 2017 and August 2022 and had taken lateral cephalogram and CBCT before and after preoperative orthodontic treatment were selected. Items were measured with lateral cephalogram including: The lower central incisor (L1)-Frankfort plane angle (L1-FH), the L1-mandibular plane angle (L1-MP), the L1-nasion-supramental angle (L1-NB) and the vertical distance from the incisal edge of lower central incisor to NB line (L1-NB distance), etc. The incidence of dehiscence/fenestration and the length of dehiscence at labial side (d-La) and lingual side (d-Li) were measured using CBCT. Pearson correlation analysis was used to evaluate the correlation between the changes of d-Li of L1 and age, duration of preoperative orthodontic treatment and the cephalometric measurements before preoperative orthodontic treatment to screen out risk factors affecting the periodontal risk of preoperative orthodontic treatment in high-angle patients with skeletal class Ⅱ malocclusions. RESULTS: After preoperative orthodontic treatment, L1-FH, L1-MP, L1-NB and L1-NB distances changed by 11.56°±5.62°, -11.13°±5.53°, -11.57°±5.43° and (-4.99±1.89) mm, respectively, and the differences were all statistically significant (P < 0.05). Among the 180 measured mandibular anterior teeth, 45 cases with labial dehiscence/fenestration before preoperative orthodontic treatment (T0) had no longer labial dehiscence/fenestration after preope-rative orthodontic treatment (T1); 142 cases without lingual dehiscence/fenestration at T0 had lingual dehiscence/fenestration at T1. After preoperative orthodontic treatment, the d-La of lower lateral incisors (L2), lower canines (L3) and lower anterior teeth (L1+L2+L3) decreased by (0.95±2.22) mm, (1.20±3.23) mm and (0.68±2.50) mm, respectively, and the differences were statistically significant (P < 0.05); the d-Li of L1, L2, L3 and L1+L2+L3 increased by (4.43±1.94) mm, (4.53±2.35) mm, (3.19±2.80) mm and (4.05±2.46) mm, respectively, and the differences were statistically significant (P < 0.05). The increase of d-Li of L1 was positively correlated with L1-FH (r=0.373, P=0.042). CONCLUSION This study showed that high-angle patients with skeletal class Ⅱ ma-locclusion could achieve ideal decompensation effect of mandibular anterior teeth after preoperative orthodontic treatment with bilateral mandibular first premolars extracted, but the lingual periodontal risk of mandibular anterior teeth was increased. This risk could be correlated to L1-FH before preoperative orthodontic treatment, which should be paid more attention in the design of orthodontic-orthognathic surgical treatment.
Humans ; Malocclusion, Angle Class III ; Malocclusion, Angle Class II/surgery* ; Facial Bones ; Incisor ; Orthognathic Surgical Procedures ; Cone-Beam Computed Tomography ; Mandible

Dentofacial deformities secondary to condylar hyperplasiais a kind of disease presenting facial asymmetry, malocclusion, temporomandibular joint dysfunction, and other symptoms caused by non-neoplastic hyperplasia of the condyle. The etiology is still unknown, and currently, pre- and post-operative orthodontics accompanied by orthognathic surgery, temporomandibular joint surgery and jawbone contouring surgery are the main treatment methods. A personalized treatment plan was developed, considering the active degree of condyle hyperplasia, the severity of the jaw deformity, and the patient's will, to correct deformity, obtain ideal occlusal relationship, and regain good temporomandibular joint function. Combined with the author's clinical experience, the etiology, clinical and imageological features, treatment aims, and surgical methods of condylar hyperplasia and secondary dentofacial deformities were discussed in this paper.
Humans ; Dentofacial Deformities/pathology* ; Hyperplasia/pathology* ; Mandibular Condyle/surgery* ; Orthognathic Surgical Procedures ; Temporomandibular Joint/surgery*

Orthognathic surgery, which involve osteotomy and repositioning of the maxillomandibular complex, has recently emerged as a crucial method of correcting dentofacial deformities. The optimal placement of the maxillomandibular complex holds utmost significance during orthognathic surgery because it directly affects the surgical outcome. To accurately achieve the ideal position of the maxillomandibular complex, with the rapid advancements in digital surgery and 3D-printing technology, orthognathic surgery has entered an era of "Precision Surgery" from the pervious "Empirical Surgery." This article provides comprehensive insights into our extensive research and exploration of the treatment modality known as "precision orthognathic surgery" over the years. We also present the technical system and application in"Ortho+X" treatment modality to offer valuable references and assistance to our colleagues in the field.
Orthognathic Surgery ; Orthognathic Surgical Procedures ; Printing, Three-Dimensional ; Surgery, Computer-Assisted

OBJECTIVE: To summarize the application and recent development of orthognathic surgery in treating syndromic craniosynostosis. METHODS: The related literature at home and abroad in recent years was extensively reviewed, and the indications, routine procedures, and protocols of orthognathic surgery in the treatment of syndromic craniosynostosis were summarized and analyzed. RESULTS: Craniosynostosis is a common congenital craniofacial malformation. Syndromic craniosynostosis usually involves premature fusion of multiple cranial sutures and is associated with other deformities. Orthognathic surgery is the necessary and effective means to improve the midfacial hypoplasia and malocclusion. Le Fort I osteotomy combined with sagittal split ramus osteotomy are the common surgical options. Orthognathic surgery should combine with craniofacial surgery and neurosurgery, and a comprehensive long-term evaluation should be conducted to determine the best treatment plan. CONCLUSION Orthognathic surgery plays an important role in the comprehensive diagnosis and treatment of syndromic craniosynostosis. The development of digital technology will further promote the application and development of orthognathic surgery in the treatment of syndromic craniosynostosis.
Humans ; Orthognathic Surgery ; Craniosynostoses/surgery* ; Osteotomy ; Osteotomy, Sagittal Split Ramus

Hypothyroidism is a common endocrine disease with reduced systemic metabolism, but the initial diagnosis is rare in oral and maxillofacial surgery. Due to the nonspecific symptoms, it is easy to be misdiagnosed and missed diagnosis which results in serious consequences. This paper presents a case of severe hypothyroidism which was characterized by airway obstruction, facial swelling, unexplained anaemia and bipedal edema after orthognathic surgery. With review of relevant literatures, this article discusses the risk factors, symptoms, diagnosis and therapy of hypothyroidism.
Edema ; Facial Bones ; Humans ; Hypothyroidism/etiology* ; Orthognathic Surgery ; Orthognathic Surgical Procedures

The maxillofacial skeleton is the basis of the contour of the face. Orthognathic surgery and facial contouring surgery change jaw tissue and affect facial appearance in different manners. Orthognathic surgery is the main method to correct dental and maxillofacial deformities. It changes the shape of the jaw and improves the occlusal relationship by changing the three-dimensional position of the jaw. Facial contouring surgery mainly adopts the method of "bone reduction", which changes the "amount"of the jawbone by cutting a part of the bone tissue to improve the facial appearance, generally without changing oral function. The combined use of orthognathic surgery and facial contouring surgery is becoming increasingly common in clinical practice. This also requires oral and maxillofacial surgeons to have a holistic consideration of the comprehensive correction of maxillofacial bone deformity, and to perform comprehensive analysis of jaw deformities and jaw plastic surgery to achieve the most ideal results. The author's team has been engaged in the clinical work of orthognathic surgery and facial contouring surgery and accumulated rich clinical experience in the comprehensive correction of maxillofacial bone deformity. In this article, the indications, treatment goals, treatment modes, treatment methods, and key points in the surgical operations of comprehensive maxillofacial bone surgery were summarized.
Face/surgery* ; Facial Bones ; Humans ; Maxillofacial Abnormalities ; Orthognathic Surgery ; Orthognathic Surgical Procedures

Treating dentofacial deformities secondary to condylar resorption is a remarkable clinical challenge. Combined orthodontic treatment and orthognathic surgery is currently the main treatment scheme and is often integrated with temporomandibular joint surgery or conservative treatment according to the severity of condylar resorption. This paper discussed the etiology, clinical features, imaging features, treatment options, and prophylaxis of condylar resorption.
Bone Resorption ; Dentofacial Deformities ; Humans ; Mandibular Condyle ; Orthognathic Surgery ; Orthognathic Surgical Procedures ; Temporomandibular Joint

Osteogenesis imperfecta is a heterogeneous group of connective tissue diseases that is predominantly characterized by bone fragility and skeletal deformity. Two siblings with undiagnosed type I osteogenesis imperfecta underwent orthognathic surgery for the treatment of facial asymmetry and mandibular prognathism. The authors report two cases of combined orthodontics and orthognathic surgery in patients with type I osteogenesis imperfecta, mandibular prognathism, and facial asymmetry.
Congenital Abnormalities ; Connective Tissue Diseases ; Facial Asymmetry ; Humans ; Orthodontics ; Orthognathic Surgery ; Osteogenesis Imperfecta ; Osteogenesis ; Prognathism ; Siblings

OBJECTIVE: There is no universally accepted method for determining the ideal sagittal position of the maxilla in orthognathic surgery. The purpose of this study was to compare how well the Delaire's cephalometric analysis correlated with postoperatively findings in patients who underwent orthognathic surgery planned using other cephalometric analyses, as well as to evaluate the feasibility of the Delaire's cephalometric analysis in predicting the ideal sagittal position of the maxilla and chin. METHODS: In the study, 35 patients with skeletal Class III malocclusion were involved and met the criteria. Treatment plans were developed using photographs, 3-D photographs, radiographs, and standard cephalometric measurements. The Delaire's cephalometric analysis data, like the phase measurements (∠C1-L1 and ∠C1-L2) of the sagittal positions of the maxillary and the chin separating the reference line (L1) of NP point and the reference line (L2) of Me point, were analyzed using Dolphin Imaging software. At the same time, the analyses on standard measurements were also performed. Four orthognathic doctors, 4 orthodontic doctors and 4 college students from non-medical majors were selected as aesthetic evaluators to assess the patients' profile aesthetic by visual analogue scale (VAS). The results through the Delaire's cephalometric analysis were statistically compared with that through standard methods. RESULTS: The mean of ∠C1-L1 was 83.93°±2.99° and∠C1-L2 was 89.08° ±2.48° for males postoperatively, and 85.67° ±3.60° and 88.30° ±4.20° for females postoperatively. Compared with the reference values of Chinese goodlooking people, there was no significant difference of NP point, whereas there was a significant difference of Me point. The postoperative aesthetic scores were: the mean was 6.71±0.25 of upper jaws, 6.81±0.30 of chins and 6.90±0.29 of the overall for males; and 7.19±0.22, 7.26±0.34 and 7.39±0.29 for females. Compared with preoperative scores, there was a significant improvement. Furthermore, the scores of chins and the overall scores were related to the sagittal position of the chins. CONCLUSION Compared with standard cephalometric analysis, the Deliare's cephalometric analysis well unravel the preoperative deformity and the final esthetic sagittal positions of maxillary and chin in the present sample, and could be a useful tool for the planning of surgery-first approach in orthognathic surgery.
Cephalometry ; Chin ; Feasibility Studies ; Female ; Humans ; Male ; Mandible ; Maxilla ; Orthognathic Surgery ; Orthognathic Surgical Procedures