• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.324-328
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• 2009

Submentovertex(SMV) projection shows the base of skull, positions of mandibular condyle and zygomatic arches. We would like to investigate how to use SMV and evaluate its availability for the construction of the plan for orthognathic surgery of mandible prognathism and asymmetry. Preoperative Surgical Treatment Objective(STO) using SMV was performed to 12 patients, who visited to Seoul National University Bundang Hospital with chief complaints like mandible prognathism or asymmetry from Dec 2007 to Feb 2009. Surgical splint was made of stone model repositioned according to STO using SMV. We estimate the change in skeletal midline and the stability of occlusion through superposition between preoperative and postoperative SMV. It was effective on the amount of mandible movement and the correction of mandibular asymmetry, while the facial asymmetry involved with maxilla was excluded. It was concluded that STO using SMV is available and predictable method for not only the setback of prognathic mandible but also the correction of mandible asymmetry accurately.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권1호
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• pp.32-36
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• 2014

Preoperative surgical simulation in orthognathic surgery has progressed in recent years; the movement of the mandible can be anticipated through three-dimensional (3D) simulation surgery before the actual procedure. In this case report, the mandible was moved to the intended postoperative occlusion through preoperative surgical 3D simulation. Right-side condylar movement change was very slight in the surgical simulation, suggesting the possibility of mandibular surgery that included only left-side ramal osteotomy. This case report describes a patient with a mild asymmetric facial profile in which the mandibular menton had been deviated to the right and the lips canted down to the left. Before surgery, three-dimensional surgical simulation was used to evaluate and confirm a position for the condyle as well as the symmetrical postoperative state of the face. Facial asymmetry was resolved with minimal surgical treatment through unilateral intraoral vertical ramus osteotomy on the left side of the mandible. It would be a valuable complement for the reduction of the surgical treatment if one could decide with good predictability when an isolated intraoral vertical ramus osteotomy can be done without a compensatory osteotomy on the contralateral side.

• Journal of Yeungnam Medical Science
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• 제25권2호
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• pp.108-116
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• 2008

Background : When surgeons plan mandible ortho surgery for patients with skeletal class III facial asymmetry, they must be consider the exact method of surgery for correction of the facial asymmetry. Three-dimensional (3D) CT imaging is efficient in depicting specific structures in the craniofacial area. It reproduces actual measurements by minimizing errors from patient movement and allows for image magnification. Due to the rapid development of digital image technology and the expansion of treatment range, rapid progress has been made in the study of three-dimensional facial skeleton analysis. The purpose of this study was to conduct 3D CT image comparisons of mandible changes after mandibular surgery in facial asymmetry patients. Materials & methods : This study included 7 patients who underwent 3D CT before and after correction of facial asymmetry in the oral and maxillofacial surgery department of Yeungnam University Hospital between August 2002 and November 2005. Patients included 2 males and 5 females, with ages ranging from 16 years to 30 years (average 21.4 years). Frontal CT images were obtained before and after surgery, and changes in mandible angle and length were measured. Results : When we compared the measurements obtained before and after mandibular surgery in facial asymmetry patients, correction of facial asymmetry was identified on the "after" images. The mean difference between the right and left mandibular angles before mandibular surgery was $7^{\circ}$, whereas after mandibular surgery it was $1.5^{\circ}$. The right and left mandibular length ratios subtracted from 1 was 0.114 before mandibular surgery, while it was 0.036 after mandibular surgery. The differences were analyzed using the nonparametric test and the Wilcoxon signed ranks test (p<0.05). Conclusion: The system that has been developed produces an accurate three-dimensional representation of the skull, upon which individualized surgery of the skull and jaws is easily performed. The system also permits accurate measurement and monitoring of postsurgical changes to the face and jaws through reproducible and noninvasive means.

• Imaging Science in Dentistry
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• 제38권4호
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• pp.203-208
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• 2008

Purpose : The purpose of this study was to develop a system for the measurement and simulation of the TMJ movement and to analyze the mandibular movement quantitatively. Materials and Methods : We devised patient-specific splints and a registration body for the TMJ movement tracking. The mandibular movements of the 12 subjects with facial deformity and 3 controls were obtained by using an optical tracking system and the patient-specific splints. The mandibular part was manually segmented from the CT volume data of a patient. Three-dimensional surface models of the maxilla and the mandible were constructed using the segmented data. The continuous movement of the mandible with respect to the maxilla could be simulated by applying the recorded positions sequentially. Trajectories of the selected reference points were calculated during simulation and analyzed. Results : The selected points were the most superior point of bilateral condyle, lower incisor point, and pogonion. There were significant differences (P<0.05) between control group and pre-surgical group in the maximum displacement of left superior condyle, lower incisor, and pogonion in vertical direction. Differences in the maximum lengths of the right and the left condyle were 0.59${\pm}$0.30 mm in pre-surgical group and 2.69${\pm}$2.63 mm in control group, which showed a significant difference (P<0.005). The maximum of differences between lengths of the right and the left calculated during one cycle also showed a significant difference between two groups (P<0.05). Conclusion : Significant differences in mandibular movements between the groups implies that facial deformity have an effect on the movement asymmetry of the mandible. (Korean J Oral Maxillofac Radiol 2008; 38 : 203-8)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제31권6호
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• pp.526-531
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• 2005

Distraction osteogenesis is a technique of bone lengthening by gradual movement and subsequent remodeling. Distraction forces applied to bone also create tension in the surrounding soft tissues, distraction histiogenesis. Distraction osteogenesis is used to correct facial asymmetry, such as patients with hemifacial microsomia, maxillary or mandibular retrusion, cleft lip & palate, alveolar defect and craniofacial deficiency. Hemifacial microsomia is characterized by unilateral facial hypoplasia, often with unilateral shortening of the mandible and subsequent malocclusion. This report describes two cases of hemifacial microsomia(type IIB). In these two cases, distraction osteogenesis was used to correct a facial asymmetry. Two patients underwent unilateral mandibular distraction osteogenesis of ascending ramus of the mandible with extraoral devices. Successful distraction osteogenesis was achieved in the patients with hemifacial microsomia.

• 대한치과교정학회지
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• 제47권3호
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• pp.195-206
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• 2017

Facial asymmetry can be classified into the rolling-dominant type (R-type), translation-dominant type (T-type), yawing-dominant type (Y-type), and atypical type (A-type) based on the distorted skeletal components that cause canting, translation, and yawing of the maxilla and/or mandible. Each facial asymmetry type represents dentoalveolar compensations in three dimensions that correspond to the main skeletal discrepancies. To obtain sufficient surgical correction, it is necessary to analyze the main skeletal discrepancies contributing to the facial asymmetry and then the skeletal-dental relationships in the maxilla and mandible separately. Particularly in cases of facial asymmetry accompanied by mandibular yawing, it is not simple to establish pre-surgical goals of tooth movement since chin deviation and posterior gonial prominence can be either aggravated or compromised according to the direction of mandibular yawing. Thus, strategic dentoalveolar decompensations targeting the real basal skeletal discrepancies should be performed during presurgical orthodontic treatment to allow for sufficient skeletal correction with stability. In this report, we document targeted decompensation of two asymmetry patients focusing on more complicated yaw-dependent types than others: Y-type and A-type. This may suggest a clinical guideline on the targeted decompensation in patient with different types of facial asymmetries.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권5호
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• pp.559-566
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• 2007

Distraction osteogenesis(DO) is a surgical method of bone formation that involves an osteotomy and sequential stretching of the healing callus by gradual movement and subsequent remodeling. DO is used to correct facial asymmetry, such as in patients with hemifacial microsomia, maxillary or mandibular retrusion, cleft lip and palate, alveolar defects, and craniofacial deficiency. It is accomplished with the aid of a distraction device, which is secured with screws placed directly into bone, for a predetermined length of time. Hemifacial microsomia is characterized by unilateral facial hypoplasia, often with unilateral shortening of the mandible and subsequent malocclusion. Patients with hemifacial microsomia and facial asymmetry have a vertically short maxilla, tilted occlusal plane, and short mandible. Early treatment is necessary to avoid subsequent impaired midfacial growth. The standard treatment of these malformations consists of the application of bone grafts, which can lead to unpredictable growth. The new bone-lengthening procedure represents a limited surgical intervention and opens up a new perspective for treatment, especially in younger children with severe deformities. This report describes a case of hemifacial microsomia(Type-II left-sided hemifacial microsomia). The patient, a 10-year-old child, visited our clinic for facial asymmetry correction. He had a hypoplastic mandible, displaced ear lobe, 10 mm canting on the right side, and malocclusion. We planned DO to lengthen the left mandible in conjunction with a Le Fort I osteotomy for decanting and then perform a right intraoral vertical ramus osteotomy(IVRO). Progressive distraction at a rate of 0.5 mm/12 hours was initiated 7 days postoperatively. The duration of DO was 17 days. The consolidation period was 3 months. Satisfactory results were obtained in our case, indicating that DO can be used successfully for functional, aesthetic reconstruction of the mandible. We report a case involving DO in conjunction with orthognathic surgery for correcting mandibular hypoplasia with a review of the literature.

• 한국임상수의학회지
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• 제40권5호
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• pp.365-369
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• 2023

Temporomandibular joint (TMJ) ankylosis is a rare disease impairing mandible movement and can either be intra-articular (true) or extra-articular (false). A cat presented with an inability to open its mouth, drooling, and facial asymmetry. Computed tomography (CT) confirmed an extracapsular abnormal TMJ fusion, and a surgical plan was devised based on the CT imaging. Post-surgery, the cat regained mouth mobility (indicating false ankylosis) and showed an improved prognosis. This case of CT-diagnosed and treated feline TMJ false ankylosis underscores the indispensable role of CT in diagnosing and devising surgical strategies for feline TMJ false ankylosis.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권5호
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• pp.447-453
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• 2010

The hemifacial microsomia is characterized by variable underdevelopment of the craniofacial skeleton, external ear, and facial soft tissues. So, patients with hemifacial microsomia have an occlusal plane canting and malocclusion with facial asymmetry. Distraction osteogenesis (DO) with an intraoral or extraoral device is a technique using tension to generate new bone with gradual bone movement and remodeling. DO has especially been used to correct craniofacial deformities such as a hemifacial microsomia, facial asymmetry, and mandible defect that could not adequately be treated by conventional reconstruction with osteotomies. It has a significant advantage to lengthen soft and hard tissue of underdeveloped site without bone graft and a few complication such as nerve injury or muscle contracture. A 13-years old girl visited our clinic for the chief complaint of facial asymmetry. She had a left hypoplastic maxilla and mandible, occlusal plane canting and malocclusion. We diagnosed hemifacial microsomia and lanned DO to lengthen the affected side. Le Fort I osteotomy, left mandibular ramus and symphysis osteotomy were performed. The internal distraction devices fixed with screw on maxillary and mandibular ramus osteotomy sites. External devices were adapted to lower jaw for DO on symphysis osteotomy site and to upper jaw for rapid maxillary expansion (RME). At 7days after surgery, distraction was started at the rate of 1mm per day for 13days, and after 4months consolidation periods, distraction devices were removed. Simultaneous multiple maxillo-mandibular distraction osteogenesis with RME resulted in a satisfactory success in correcting facial asymmetry as well as occlusal plane canting for our hemifacial microsomia.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권5호
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• pp.373-381
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• 2021

Objectives: In the present study, the effects of sagittal split ramus osteotomy (SSRO) combined with intraoral vertical ramus osteotomy (IVRO) for the treatment of asymmetric mandible in class III malocclusion patients were assessed and the postoperative stability of the mandibular condyle and the symptoms of temporomandibular joint disorder (TMD) evaluated. Materials and Methods: A total of 82 patients who underwent orthognathic surgery for the treatment of facial asymmetry or mandibular asymmetry at the Department of Oral and Maxillofacial Surgery, Dong-A University Hospital, from 2016 to 2021 were selected. The patients that underwent SSRO with IVRO were assigned to Group I (n=8) and patients that received bilateral SSRO (BSSRO) to Group II (n=10, simple random sampling). Preoperative and postoperative three-dimensional computed tomography (CT) axial images obtained for each group were superimposed. The condylar position changes and degree of rotation on the superimposed images were measured, and the changes in condyle based on the amount of chin movement for each surgical method were statistically analyzed. Results: Group I showed a greater amount of postoperative chin movement. For the amount of mediolateral condylar displacement on the deviated side, Groups I and II showed an average lateral displacement of 0.07 mm and 1.62 mm, respectively, and statistically significantly correlated with the amount of chin movement (P=0.004). Most of the TMD symptoms in Group I patients who underwent SSRO with IVRO showed improvement. Conclusion: When a large amount of mandibular rotation is required to match the menton to the midline of the face, IVRO on the deviated side is considered a technique to prevent condylar torque. In the present study, worsening of TMD symptoms did not occur after orthognathic surgery in any of the 18 patients.