• Imaging Science in Dentistry
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• v.47 no.2
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• pp.93-97
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• 2017

Purpose: The purpose of this study was to evaluate the accuracy of panoramic imaging in measuring the right and left gonial angles by comparing the measured angles with the angles determined using a lateral cephalogram of adult patients with class I malocclusion. Materials and Methods: The gonial angles of 50 class I malocclusion patients (25 males and 25 females; mean age: 23 years) were measured using both a lateral cephalogram and a panoramic radiograph. In the lateral cephalograms, the gonial angle was measured at the point of intersection of the ramus plane and the mandibular plane. In the panoramic radiographs, the gonial angle was measured by drawing a line tangent to the lower border of the mandible and another line tangent to the distal border of the ascending ramus and the condyle on both sides. The data obtained from both radiographs were statistically compared. Results: No statistically significant difference was observed between the gonial angle measured using the lateral cephalograms and that determined using the panoramic radiographs. Further, there was no statistically significant difference in the measured gonial angle with respect to gender. The results also showed a statistically insignificant difference in the mean of the right and the left gonial angles measured using the panoramic radiographs. Conclusion: As the gonial angle measurements using panoramic radiographs and lateral cephalograms showed no statistically significant difference, panoramic radiography can be considered in orthodontics for measuring the gonial angle without any interference due to superimposed images.

• Journal of Veterinary Clinics
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• v.25 no.6
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• pp.545-548
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• 2008

A 3-year-old castrated male Siberian husky was presented for evaluation after being hit by a car. On physical examination, the dog showed open-mouth, displacement of mandible and hypersalivation with blood ting. The base of tongue was transected almost 80% on the bias from right dorsal side to the left ventral side. Radiography demonstrated separation of mandible symphysis, and fracture of right condyle and vertical ramus. After debridement of the necrotic tissue, tongue apposition with simple interrupted suture was performed. Mandibular symphysis, condyle and mandibular vertical ramus fractures were fixed using pin, cerclage wire, T-plate, and K-wires. The mouth was irrigated daily using chlorhexidine after surgery. The sutures that were loose here or untied at tongue were re-sutured under sedation. The transected tongue was healed and recovered its normal movement after 6 weeks.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.4
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• pp.255-268
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• 1992

There are various modalities in the treatment of facial asymmetry, but in severe case with TMD by actively growing deformed condyle, the treatment choice is removing the condyle growth center and TMD symptom such as click or muscular discomfort. In our one case, the patient was complain of facial asymmetry. There are severe deformed condyle head with bird-head fashion and enlarged mandibular ramus and body vertically about 18 mm, overgrowthed Rt. mandible body horizontally about 20 mm. She had intermittent Lt. TMJ clicking and muscular discomfort. The author diagnosed it as Lt. hemimandibular hyper-plasia & R, hemimandibular elongation, a combination form with TMD. the condyle was in active growing state in scintigraphic analysis. So we extirpated the deformed condyle by intrasoral sagittal split ramus osteotomy and reshaped the condyle and mandibular distal fragment extraorally. The distal fragment was readapted in glenoid fossa and fixated. In Rt. mandibular body area, autogenous onlay bone graft on the inferior border of mandible was performed to correct the asymmetry. The clicking and facial asymmetry was corrected and we report this results with other literature findings.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.2
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• pp.130-136
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• 2005

Bone grafts are widely used in the reconstruction of osseous defects in the oral and maxillofacial region. Autogenous bone grafts are considered the gold standard in grafting of the oral and maxillofacial region, because of its osteoconductive and osteoinductive properties. Mandibular symphysis & ascending ramus bone graft have been used more frequently because of easy surgical access, reduced operative time, and following minimal morbidity. However, even though the frequent use of the anterior part of ascending ramus and the different regions of mandible, rare of the reports provide information about the quantity of bone available in this donor site. So this study was taken to evaluate & quantify the amount of bone graft material in the anterior ascending ramus regions. This study was made on 36 samples of CT image. In 3D volume image, imaginary osteotomy & segmentation were done and the dimensions and volume of the bone grafts were measured and evaluated. the average volume of the graft materials obtained from the ascending ramus was $3656.83{\pm}108.19mm^3$, and the average dimensions of graft materials were $(33.68{\pm}0.48){\times}(34.92{\pm}0.51){\times}(15.96{\pm}0.27){\times}(9.05{\pm}0.27)mm$.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.547-554
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• 2005

Orthognathic surgery for Class III malocclusion requires an elaborate preoperative planning using cephalometries or Mock surgery models which enable the surgeon to anticipate postoperative skeletal changes of maxilla and mandible as well as dentition. After surgery, patient's satisfaction is greatly influenced by appearance of soft tissue change. Therefore, it is imperative to predict a relatively accurate soft tissue change prior to surgery. A 5 year retrospective study was designed to evaluate the soft tissue change after sagittal split osteotomy of ramus(SSRO) for class III malocclusion. Analyses of preoperative and postoperative anthropometric measurements were performed. Patients who were treated only by SSRO for class III malocclusion and could follow up for 6 months were studied. Among them, the patients who had history of cleft palate and lip or hemifacial microsomia were excluded. Soft tissue changes were estimated by using the frontal and lateral photographs. Skeletal changes were observed by measuring amount of set back and angular changes of mandible to the reference line by using cephalometries. Relapses were also measured 6 months after the operation. We could observe skeletal changes were more profound than soft tissue changes concerning amount of set back, but soft tissue changes were also profound in angle. Relapse was more profound in skeleton than soft tissue but the amount was not significant. In spite of the variables which may affect proper assessment of the soft tissue change after skeletal relocation, this study can serve as a guide for exact prediction of the postoperative change of soft tissue and skeleton.

• The korean journal of orthodontics
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• v.50 no.5
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• pp.324-335
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• 2020

Objective: To compare postoperative positional changes in the mandibular proximal segment between the conventional orthognathic surgery (CS) and the surgery-first approach (SF) using intraoral vertical ramus osteotomy (IVRO) in patients with Class III malocclusion. Methods: Thirty-eight patients with skeletal Class III malocclusion who underwent bimaxillary surgery were divided into two groups according to the use of preoperative orthodontic treatment: CS group (n = 18) and SF group (n = 20). Skeletal changes in both groups were measured using computed tomography before (T0), 2 days after (T1), and 1 year after (T2) the surgery. Three-dimensional (3D) angular changes in the mandibular proximal segment, condylar position, and maxillomandibular landmarks were assessed. Results: The mean amounts of mandibular setback and maxillary posterior impaction were similar in both groups. At T2, the posterior portion of the mandible moved upward in both groups. In the SF group, the anterior portion of the mandible moved upward by a mean distance of 0.9 ± 1.0 mm, which was statistically significant (p < 0.001). There were significant between-group differences in occlusal changes (p < 0.001) as well as in overjet and overbite. However, there were no significant between-group differences in proximal segment variables. Conclusions: Despite postoperative occlusal changes, positional changes in the mandibular proximal segment and the position of the condyles were similar between CS and SF, which suggested that SF using IVRO achieved satisfactory postoperative stability. If active physiotherapy is conducted, the proximal segment can be adapted in the physiological position regardless of the occlusal changes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.3
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• pp.258-265
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• 2001

A prognathic mandible and prominent gonial angle are considered to be unattractive in the Orient because it gives the face a square and muscular appearance. Requests for contouring of the mandibular angle are rare in the other race but are much more common in Korea and, through out the Orient. So, we often encounter a patient with a prognathic mandible and squarish or broad face who wishes to have his or her facial size reduced minimally or to acquire a round or slender appearance. But, mandibular angle is located in the deepest part of the operative field and the strong tension of the lateral soft tissue makes retraction difficult. It is extremely difficult to reduce the gonial angle with sagittal split ramus osteotomy by intraoral approach at the same time. We apply the method of gonial angle reduction during SSRO and had satisfactory results. We will present our results and hope to give some useful information for management of mandibular deformity.

• Imaging Science in Dentistry
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• v.49 no.1
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• pp.71-77
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• 2019

Primary intraosseous squamous cell carcinoma is a rare malignant central jaw tumor derived from odontogenic epithelial remnants. Predominantly, it affects mandible, although both jaw bones may be involved. This report describes a 60-year-old man who was initially misdiagnosed with a periapical infection related to the right lower wisdom tooth. After four months, the patient presented to a private dental clinic with a massive swelling at the right side of the mandible. Panoramic radiographs and advanced imaging revealed a lesion with complete erosion of the right ramus, which extended to the orbital floor. A biopsy from the mandibular angle revealed large pleomorphic atypical squamous cells, which is the primary microscopic feature of a poorly differentiated squamous cell carcinoma.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.509-519
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• 2000

Enlow's counterpart analysis explains the complex with anatomic and developmental characteristics where craniofacial aspect of individuals has been developed. The analysis does not compare individual measurement with the normal value from the average of majority but analyzes by comparison of values that each individual has. This study was to clarify the Korean craniofacial skeletal pattern using Enlow's counterpart analysis considering the fact that the craniofacial skeletal pattern has racial and regional variations. This research will be helpful in the future for growth research and research of the orthognathic surgery. For this study, the samples were consisted of 100 Korean adult subjects(50 males and 50 females) who had normal occlusion and pleasing face. Measurement points and lines were established using Enlow's counterpart analysis and they were statistically evaluated. The results indicated that : 1. The average angle between PCF and PMV was $38.54^{\circ}$ in males and $38.43^{\circ}$ in females, and the average Wits' appraisal was -2.51 in males and -2.3 in females. The ramus alignment(R4) was 1.89 in males and 2.36 in females. 2. It shows that females have a longer ramus than the PCF compared to the males, because there was a significant difference in Ramus/PCF horizontal dimensions (Skeletal A3-B3) between female and male subjects 3. It shows that males have a longer mandibular corpus than the maxilla compared to the females, because there was a significant difference in Maxillary/Mandibular arches(Skeletal A4-B4) between male and female subjects 4. In cranial floor+maxilla/ramus+corpus at A and B points(Al-Bl), which represents difference in total horizontal length between the maxilla and mandible, there was no significant difference between males and females. In conclusions, compared to Caucasian, Korean have more depressed midface, prognathic mandible, and ramus that rotates inferioposterior. Also, we observe that Korean women have target ramus posterior cranial base, as compared with Korean men. Consequently, the total length of maxilla and mandible does not show any difference, because man's mandible is longer than maxilla in comparison with woman's one.

• Journal of Oral Medicine and Pain
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• v.42 no.4
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• pp.109-115
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• 2017

Purpose: This study analyzed the effects of digastric muscle injury on mandibular growth in young rats. Methods: Fourteen 4-week-old Wistar rats were divided into 3 groups; experimental group A (n=6) with unilateral (right) shortening of the posterior digastric muscle, experimental group B (n=6) with bilateral shortening of the posterior digastric muscles, and control group C (n=2) who underwent a sham operation. Eight weeks after the operation all animals were sacrificed and the outcomes were compared using body weight evaluation, mensurations on lateral radiograph of hemimandibles and histological evaluation. Results: There was no significant difference between groups A and B in body weight gain. Comparison of the mean values of hemimandible distance on radiograph was performed. The difference in group mean value of mandible-related distances was analyzed using the Wilcoxon test (rank sum test) and a comparison of the homonymous distances of group A and B was performed using the Mann-Whitney test. There were differences between sides in mandibular length in group B and mandibular ramus height and transverse width of the condyle in group A (all, p<0.05). There were differences in condylar height and mandibular length on the left side between groups A and B (p<0.05). Histologic examination of temporomandibular joint showed similar findings in all specimens. Conclusions: Injury of the posterior belly of the digastric muscle during the rat growth period induced shortening of mandibular ramus height and transverse width of the condyle. It can be inferred that trauma to the posterior belly of the digastric muscle affects horizontal and vertical growth of the mandible.