In light of the increasing digitalization of dentistry, the automatic determination of three-dimensional (3D) craniomaxillofacial features has become a development trend. 3D craniomaxillofacial landmarks and symmetry reference plane determination algorithm based on point clouds has attracted a lot of attention, for point clouds are the basis for virtual surgery design and facial asymmetry analysis, which play a key role in craniomaxillofacial surgery and orthodontic treatment design. Based on the studies of our team and national and international literatures, this article presented the deep geometry learning algorithm to determine landmarks and symmetry reference plane based on 3D craniomaxillofacial point clouds. In order to provide reference for future clinical application, we describe the development and latest research in this field, and analyze and discuss the advantages and limitations of various methods.
Humans ; Imaging, Three-Dimensional/methods* ; Facial Asymmetry ; Algorithms

OBJECTIVE: To preliminarily verify the effectiveness of self-designed artificial condyle-mandibular distraction (AC-MD) complex in the treatment of Pruzansky type ⅡB and Ⅲ hemifacial microsomia (HFM) through model test. METHODS: Five children with Pruzansky type ⅡB and Ⅲ HFM who were treated with mandibular distraction osteogenesis (MDO) between December 2016 and December 2021 were selected as the subjects. There were 3 boys and 2 girls wih an average age of 8.4 years (range, 6-10 years). Virtual surgery and model test of AC-MD complex were performed according to preoperative skull CT of children. The model was obtained by three-dimensional (3D) printing according to the children's CT data at a ratio of 1∶1. The occlusal guide plate was designed and 3D printed according to the children's toothpaste model. The results of the model test and the virtual surgery were matched in three dimensions to calculate the error of the residual condyle on the affected side, and the model test was matched with the actual skull CT after MDO to measure and compare the inclination rotation of the mandible, the distance between the condylar of the healthy side and the residual condyle of the affected side, and the lengthening length of the mandible. RESULTS: The error of residual condyle was (1.07±0.78) mm. The inclination rotation of the mandible, the distance between the condylar of the healthy side and the residual condyle of the affected side, and the lengthening length of the mandible after 3D printing model test were significantly larger than those after MDO ( P<0.05). CONCLUSION In the model test, the implantation of AC-MD complex can immediately rotate the mandible to the horizontal position and improve facial symmetry, and the residual condyle segment can be guided close to the articular fossa or the preset pseudoarticular position of the skull base after operation.
Male ; Child ; Female ; Humans ; Goldenhar Syndrome/surgery* ; Mandible/surgery* ; Osteogenesis, Distraction/methods* ; Printing, Three-Dimensional ; Facial Asymmetry/surgery*

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: To establish a novel method based on three-dimensional (3D) shape analysis and weighted Procrustes analysis (WPA) algorithm to construct a 3D facial symmetry reference plane (SRP), automatically assigning weight to facial anatomical landmarks. The WPA algorithm suitability for commonly observed clinical cases of mandibular deviation were analysed and evaluated. METHODS: Thirty patients with mandibular deviation were recruited for this study. The 3D facial SRPs were extracted independently based on original-mirror alignment method. Thirty-two anatomical landmarks were selected from the overall region by three times to obtain the mean coordinate. The SRP of experimental groups 1 and 2 were using the standard Procrustes analysis (PA) algorithm and WPA algorithm, respectively. A reference plane defined by experts based on regional iterative closest point (ICP) algorithm, served as the ground truth. Three experts manually selecting facial regions with good symmetry for original model, and common region was included in the study. The angle error values between the SRP of WPA algorithm in the experimental group 1 and the truth plane were evaluated in this study, and the SRP of PA algorithm of experimental group 2 was calculated in the same way. Statistics and measurement analysis were used to comprehensively evaluate the clinical suitability of the WPA algorithm to calculate the SRP. A paired t-test analysis (two-tailed) was conducted to compare the angles. RESULTS: The average angle error between the SRP of WPA algorithm and the ground truth was 1.53°±0.84°, which was smaller than that between the SRP of PA and the ground truth (2.06°±0.86°). There were significant differences in the angle errors among the groups (P < 0.05). For the patients with severe mandibular deviation that the distance between pogonion and facial midline greater than 12 mm, the average angle error of the WPA algorithm was 0.86° smaller than that of the PA algorithm. CONCLUSION The WPA algorithm, based on weighted shape analysis, can provide a more adaptable SRP than the standard PA algorithm when applied to mandibular deviation patients and preliminarily simulate the diagnosis strategies of clinical experts.
Algorithms ; Cephalometry ; Face ; Facial Asymmetry ; Humans ; Imaging, Three-Dimensional

BACKGROUND AND OBJECTIVES: The aim of the present study was to assess the feasibility of a PC-based facial asymmetry assessment program (PC-FAAP) and to compare the results of PC-FAAP with subjective regional scoring by raters in acute unilateral peripheral facial nerve paralysis (FNP). SUBJECTS AND METHODS: Participants were divided into 3 groups with 8 participants per group: group I, normal; group II, mild to moderate FNP; and group III, severe FNP. Using the PC-FAAP, the mouth asymmetry ratio (MAR), eyebrow asymmetry ratio (EAR), and complete eye closure asymmetry ratio (CAR) were calculated by comparing the movement of tracking points on both sides. The FNP grading scale (FGS) integrated each score, and the scores were weighted with a ratio of 5:3:2 (MAR:CAR:EAR). Subjective regional scoring was measured on a 0-100 scale score by three otologists. PC-FAAP and subjective scoring were compared in each group regarding the consistency of the results. RESULTS: The mean scores of the MAR, EAR, CAR, and FGS of each group were significantly different. PC-FAAP showed significant differences between the three groups in terms of MAR, EAC, CAR, and FGS. PC-FAAP showed more consistent results than subjective assessment (p < 0.001). The PC-FAAP was significantly more consistent in group I and group III (p < 0.001 and p=0.002, respectively). FGS in group III was the only parameter that showed a more consistent result in PC-FAAP than the subjective scoring (p=0.008). CONCLUSIONS: An FNP grading system using a PC-based program may provide more consistent results, especially for severe forms.
Ear ; Eyebrows ; Facial Asymmetry ; Facial Nerve ; Mouth ; Paralysis

BACKGROUND: Parotidectomy is the treatment of choice in many parotid tumors. Due to the extensive nature of the procedure, unfavorable complications such as gustatory sweating, surgical site depression are common. Various techniques using fascia, muscle or AlloDerm have been developed but debate still remains regarding its availability and affordability. We applied a newly developed acellular dermal matrix (Insuregraf) to the parotidectomy field to act as a physical barrier and to provide adequate filling effect for prevention of functional and aesthetic complications. METHODS: From March 2010 to March 2017, 30 patients with parotid tumors underwent superficial parotidectomy. Twenty patients underwent only superficial parotidectomy. Ten patients had Insuregraf applied to the surgical site after superficial parotidectomy. We evaluated the incidence of Frey’s syndrome, surgical site depression, and patient satisfaction rate in both groups. RESULTS: The incidence of Frey’s syndrome was lower in the Insuregraf group (0 vs. 2). Surgical site depression was also lower in the Insuregraf group (2 vs. 20). Satisfaction score for facial contour in Insuregraf group was 9.2 out of 10, which was comparable to 6.2 out of 10 in the control group. CONCLUSION: Application of Insuregraf after superficial parotidectomy is an effective surgical procedure to prevent complications such as Frey’s syndrome and surgical site depression. This technique is affordable and safe with no immune reactions. Above all this surgical method should be considered as an option for patients who are concerned about the contour of the face after surgery.
Acellular Dermis ; Architectural Accessibility ; Collagen ; Depression ; Facial Asymmetry ; Fascia ; Humans ; Incidence ; Methods ; Parotid Neoplasms ; Patient Satisfaction ; Sweating, Gustatory

Post-traumatic hematoma formation is a common complication of contusion. If the hematoma is large enough to aspirate or drain, it can be treated quickly and appropriately. However, if the hematoma is small or concealed by local swelling, it may be overlooked and left untreated. In most cases, a hematoma will resolve following conservative treatment; however, associated infection or muscle fibrosis can occur. Herein, we present the case of a patient with a chin deformity caused by a post-traumatic hematoma. The deformity was treated using botulinum toxin and triamcinolone acetonide injections as minimally invasive treatments. The course of treatment was good.
Botulinum Toxins ; Chin ; Congenital Abnormalities ; Contusions ; Facial Asymmetry ; Fibrosis ; Hematoma ; Humans ; Triamcinolone Acetonide

OBJECTIVE: Precise identification of landmarks on posteroanterior (PA) cephalograms is necessary when evaluating lateral problems such as facial asymmetry. The aim of the present study was to investigate whether the use of lateral (LA) cephalograms can reduce errors in landmark identification on PA cephalograms. METHODS: Five examiners identified 16 landmarks (Cg, N, ANS, GT, Me, RO, Lo, FM, Z, Or, Zyg, Cd, NC, Ms, M, and Ag) on 32 PA cephalograms with and without LA cephalograms at the same time. The positions of the landmarks were recorded and saved in the horizontal and vertical direction. The mean errors and standard deviation of landmarks location according to the use of LA cephalograms were compared for each landmark. RESULTS: Relatively small errors were found for ANS, Me, Ms, and Ag, while relatively large errors were found for N, GT, Z, Or, and Cd. No significant difference was found between the horizontal and vertical errors for Z and Or, while large vertical errors were found for N, GT, and Cd. The value of identification error was lower when the landmarks were identified using LA cephalograms. Statistically significant error reductions were found at N and Cd with LA cephalograms, especially in the vertical direction. CONCLUSIONS: The use of LA cephalograms during identification of landmarks on PA cephalograms could help reduce identification errors.
Facial Asymmetry

BACKGROUND: Fibrous dysplasia (FD) is a benign bone lesion characterized by the progressive replacement of normal bone with fibro-osseous connective tissue. The maxilla is the most commonly affected area of facial bone, resulting in facial asymmetry and functional disorders. Surgery is an effective management option and involves removing the diseased bone via an intraoral approach: conservative bone shaving or radical excision and reconstruction. CASE PRESENTATION: This case report describes a monostotic fibrous dysplasia in which the patient’s right midface had a prominent appearance. The asymmetric maxillary area was surgically recontoured via the midfacial degloving approach under general anesthesia. Follow-up photography and radiographic imaging after surgery showed the structures were in a stable state without recurrence of the FD lesion. Furthermore, there were no visible scars or functional disability, and the patient reported no postoperative discomfort. CONCLUSIONS: In conclusion, the midfacial degloving approach for treatment of maxillary fibrous dysplasia is a reliable and successful treatment option. Without visible scars and virtually free of postoperative functional disability, this approach offers good exposure of the middle third of the face for treatment of maxillary fibrous dysplasia with excellent cosmetic outcomes.
Anesthesia, General ; Cicatrix ; Connective Tissue ; Facial Asymmetry ; Facial Bones ; Fibrous Dysplasia, Monostotic ; Follow-Up Studies ; Humans ; Maxilla ; Photography ; Recurrence

BACKGROUND: Fibrous dysplasia (FD) is characterized by the replacement of normal bone by abnormal fibro-osseous connective tissue and typically treated with surgical contouring of the dysplastic bone. When dysplastic lesions involve occlusion, not only is surgical debulking needed, orthognathic surgery for correction of dentofacial deformity is mandatory. However, the long-term stability of osteotomized, dysplastic bone segments is a major concern because of insufficient screw-to-bone engagement during surgery and the risk of FD lesion re-growth. CASE PRESENTATION: This case report reviewed two patients with non-syndromic FD that presented with maxillary occlusal canting and facial asymmetry. Le Fort I osteotomy with recontouring of the dysplastic zygomaticomaxillary region had been performed. The stability of osseous segments were favorable. However, dysplastic, newly formed bone covered the previous plate fixation site and mild bony expansion was observed, which did not influence the facial profile. Including the current cases, 15 cases of orthognathic surgery for FD with dentition have been reported in the literature. CONCLUSION: The results showed that osteotomy did not appear to significantly reduce the long-term stability of the initial fixation insufficiency of the screw to the dysplastic bone. However, based on our results and those of the others, long-term follow-up and monitoring are needed, even in cases where the osteotomized segment shows stable results.
Connective Tissue ; Dentition ; Dentofacial Deformities ; Facial Asymmetry ; Follow-Up Studies ; Humans ; Orthognathic Surgery ; Osteotomy