• The korean journal of orthodontics
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• v.39 no.1
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• pp.18-27
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• 2009

Objective: The purpose of this study was to understand the differences in masseter muscle(MM) between the shifted and non-shifted sides in facial asymmetry patients, and the changes shown by MM after mandibular surgery. Methods: Pre- and post-operative CT scans were performed on 12 Class III patients with facial asymmetry who were treated by intraoral vertical ramus osteotomy and 10 subjects with normal occlusion. Using the V-works 4.0 program(Cybermed, Seoul, Korea), 3-dimensional images of the mandible, and MM were reconstructed, and evaluated. Results: In the asymmetry group, the MM angle between the shifted and non-shifted sides was only significantly different(p<0.05). Compared with normal occlusion, the asymmetry group showed a significantly smaller volume and maximum cross-sectional area in both sides of MM(p<0.05). After mandibular surgery, the angle of MM(p<0.01) and differences in angle between the shifted and non-shifted sides of MM(p<0.05) were significantly decreased. The thickness in the maximum cross-sectional area was significantly increased(p<0.01). After surgery, MM in facial asymmetry patients was similarly changed to those in the normal occlusion group except for widths. Conclusions: MM in facial asymmetry was definitely different from those in normal occlusion. However, this study suggests that MM changed symmetrically in conjunction with the mandible after proper mandibular surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.18.1-18.9
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• 2016

Background: The aim of this study was to examine the relationship between improvements in lip asymmetry at rest and while smiling after orthognathic surgery in patients with skeletal class III malocclusion. Methods: This study included 21 patients with skeletal class III malocclusion and facial asymmetry. We used preoperative and postoperative CT data and photographs to measure the vertical distance of the lips when smiling. The photographs were calibrated based on these distances and the CT image. We compared preoperative and postoperative results with the t test and correlations between measurements at rest and when smiling by regression analyses. Results: There were significant correlations between the postoperative changes in canting of the mouth corners at rest, canting of the canines, canting of the first molars, the slope of the line connecting the canines, and the slope of the line connecting first molars. The magnitude of the postoperative lip line improvement while smiling was not significantly correlated with changes in the canting and slopes of the canines, molars, and lip lines at rest. Conclusions: It remains difficult to predict lip line changes while smiling compared with at rest after orthognathic surgery in patients with mandibular prognathism, accompanied by facial asymmetry.

• The korean journal of orthodontics
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• v.33 no.5 s.100
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• pp.391-398
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• 2003

Distraction osteogenesis is a well-estabilished procedure of membraneous bone formation and has been used to correct craniofacial deformities in dentofacial orthopedic-surgery area for decades. In this articale, distraction osteogenesis is used for treatment of facial asymmetry. The patient underwent procedures to lengthen the mandibular ramus and body. After distraction, orthodontic treatment was done for ooclusal settling.

• Archives of Plastic Surgery
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• v.39 no.4
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• pp.291-300
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• 2012

The incidence of condylar fractures is high,but the management of fractures of the mandibular condyle continues to be controversial. Historically, maxillomandibular fixation, external fixation, and surgical splints with internal fixation systems were the techniques commonly used in the treatment of the fractured mandible. Condylar fractures can be extracapsular or intracapsular, undisplaced, deviated, displaced, or dislocated. Treatment depends on the age of the patient, the co-existence of other mandibular or maxillary fractures, whether the condylar fracture is unilateral or bilateral, the level and displacement of the fracture, the state of dentition and dental occlusion, and the surgeonnds on the age of the patient, the co-existence of othefrom which it is difficult to recover aesthetically and functionally;an appropriate treatment is required to reconstruct the shape and achieve the function ofthe uninjured status. To do this, accurate diagnosis, appropriate reduction and rigid fixation, and complication prevention are required. In particular, as mandibular condyle fracture may cause long-term complications such as malocclusion, particularly open bite, reduced posterior facial height, and facial asymmetry in addition to chronic pain and mobility limitation, great caution should be taken. Accordingly, the authors review a general overview of condyle fracture.

• Archives of Craniofacial Surgery
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• v.22 no.1
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• pp.45-51
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• 2021

Background: Mandibular deficiency leading to facial asymmetry causes cosmetic deformity as well as psychological stigma for the patient. Correction of these mandibular asymmetries is a major challenge. The study investigates the efficacy of bidirectional mandible distraction for the treatment of mandibular deficiency. Methods: This prospective study included six individuals aged between 17 and 24.4 years. Five patients had hemifacial microsomia and one had unilateral temporomandibular joint ankyloses. All patients underwent mandibular distraction osteogenesis. Postoperative skeletal changes in affected mandible, and changes in occlusal plane and oral commissure cant were evaluated using three-dimensional reconstruction. Patient satisfaction and understanding of the procedure were assessed through three questionnaires administered during pre-distraction, distraction and post-distraction phases. Results: In pre-distraction phase, aesthetic appearance seemed to be the primary indication for surgery. In distraction phase, pain while chewing was the primary handicap. In post-distraction phase all patients were satisfied with the aesthetic outcome. The facial deformity was improved through mandibular distraction osteogenesis. On the affected side in all the patients, height and length of the mandible increased. Canting of the occlusal plane and oral commissure was corrected. Conclusion: Bidirectional mandible distraction is an effective treatment for correction of mandible deformities in adult patients.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.3
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• pp.259-266
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• 2005

The function of the masseter and anterior temporal muscles was assessed by electromyography in 30 patients with mandibular prognathism (20 patients with facial asymmetry and 10 patients without facial asymmetry) before orthognathic surgery and 4weeks afterwards. Electromyogram(EMG) recordings were made during resting, clenching and swallowing. We compared with right-left difference of this recording and asymmetry index before and after orthognathic surgery. The result of this study was as follows. 1. There was no significant right-left difference in muscle activities of masticatory muscles both asymmetric groups and controls and many variable change after orthognathic surgery.(P>0.05) 2. The mean electric activity of the masticatory muscles was found to have decreased during more clenching than resting, but there was no statistically significant difference because of individual difference of measuring values.(P>0.05) 3. The asymmetry index of masticatory muscles in asymmetric groups was significantly greater during clenching compared with controls.(P<0.05) In conclusion, no right-left difference of muscle activities was found in patients with facial asymmetry before orthognathic surgery and 4weeks afterwards. Not only muscular functioning but also many other factors, such as occlusion, temporomandibular joint disorder and trauma, probably affect facial asymmetry and will be analyzed in future studies. And we will need long term follow-up after orthognathic surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.3
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• pp.266-273
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• 2005

Purpose: To assess the relationship between soft tissue reference line and hard tissue reference line using the standardized photographs and the posteroanterior cephalometric radiographs(P-A)in facial asymmetric patients and to compare the differences of angular measurement between normal group and asymmetry group. Methods: Normal group consisted of 44 persons with normal occlusion and normal facial morphology. Asymmetry group consisted of 90 patients with facial asymmetry. Standardized facial photographs and P-A were taken in all subjects. The horizontal reference lines were bipupillary line in photographs and latero-orbitale line in P-A respectively. The vertical reference line were the line from the midpoint of horizontal reference line perpendicularly. Angular measurement of otobasion canting, lip canting, nose deviation, chin deviation, and maxillary deviation were compared and analyzed in photographs. And angular measurement of mastoid canting, mandibular canting, nose deviation, chin deviation, and maxillary deviation were compared and analyzed in P-A. Results: 1. The variables of photographs and P-A were significantly related in the asymmetry group. 2. Significant differences between all variables except for PT2 and PA2 were shown in the asymmetry group and between PT1 and PA1, PT3 and PA3 in the normal group respectively. 3. Comparison measurement scores of angular difference between control group and experimental group concerning each variable showed significant difference except for PA1. Conclusions: Soft tissue components may not compensate for underlying skeletal imbalance in nose deviation and chin deviation. The horizontal reference lines in photographs were significant related with the P-A, but angular variables between the two studies show significant differences. Therefore, we do not recommend use photography in the assessment the facial asymmetry as complemented in the P-A.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.1
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• pp.63-67
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• 2022

Controversies exist regarding the need for prophylactic extraction of mandibular third molars in patients who plan to undergo orthognathic surgery. An 18-year-old male patient was diagnosed with mandibular prognathism and maxillary retrognathism with mild facial asymmetry. He had a severely damaged mandibular first molar and a horizontally impacted third molar. After extraction of the first molar, the second molar was protracted into the first molar space, and the third molar erupted into the posterior line of occlusion. The orthognathic surgery involved clockwise rotation of the maxillomandibular complex as well as angle shaving and chin border trimming. Patients who are missing or have damaged mandibular molars should be monitored for eruption of third molars to replace the missing posterior tooth regardless of the timing of orthognathic surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.6
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• pp.584-588
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• 2008

Facial asymmetry is particularly associated with mandible among other facial bones and it could be either congenital or acquired. Congenital factors are related to Treacher Collin syndrome, Pierre Robin syndrome, hemifacial microsomia and other various syndromes. Acquired factors are such as damaged or diseased growing condyles, hormonal disorder, oral mal-habit, muscular force, tumor, infection and so on. Diagnosis and treatment of facial asymmetry are complicated due to differences in sizes and positions of mandibles. The aspects of facial asymmetry is various and complicated upon each individual. Depending on causes of the facial asymmetry, there also are morphological differences. For such reasons, precise anatomical analysis and diagnosis of the facial asymmetry are essential before any surgical procedure followed by the appropriate treatment plan. This case is regarding a 21-year old patient diagnosed as the facial asymmetry due to an infantile maxillofacial surgery. Employing various morphological evaluations, potential problems during the procedure are predicted beforehand. This case reports a favorable result of sagittal split ramus osteotomy performing the oblique vertical bone cutting in posterior-superior of the mandibular second molar.

• Korean Journal of Veterinary Research
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• v.53 no.4
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• pp.207-210
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• 2013

Fifteen dry dentate and complete mandible samples from the White Rasquera goat breed were studied for symmetry. Thirty-one landmarks were digitally located on the images of the lateral and medial aspects of each hemimandible. Distances between these landmarks allowed the evaluation of the whole hemimandible and also the neural mandible. In the studied samples, the mandible was rather symmetrical, especially in the medial neural part, and in general, there was no side dominance. Only the diastema differed significantly between the sides, and this was related to the rostral part (incisive arch). The incisive region was the least symmetrical region of the caprine mandible, indicating a modular structure more conservative for the neural part. If unsigned asymmetry is interpreted as a measure of developmental stability, then the studied breed presented a marked ability to develop in good fitness despite the harsh environment. The measurements presented here can also be used as a reference for researchers designing experimental studies, especially on mandibular catch-up growth, and as an aid for zooarchaeologists comparing results from dead animals with those from living goat populations.