• The korean journal of orthodontics
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• v.43 no.6
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• pp.263-270
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• 2013

Objective: To evaluate condylar head remodeling after mandibular set-back sagittal split ramus osteotomy (SSRO) with rigid fixation in skeletal class III deformities. The correlation between condylar head remodeling and condylar axis changes was determined using cone-beam computed tomography (CBCT) superimposition. Methods: The CBCT data of 22 subjects (9 men and 13 women) who had undergone mandibular set-back SSRO with rigid fixation were analyzed. Changes in the condylar head measurements and the distribution of the signs of condylar head remodeling were evaluated by CBCT superimposition. Results: The subjects showed inward rotation of the axial condylar angle; reduced condylar heights on the sagittal and coronal planes; and resorptive remodeling in the anterior and superior areas on the sagittal plane, superior and lateral areas on the coronal plane, and anterior-middle and anterior-lateral areas on the axial plane (p < 0.05). Conclusions: The CBCT superimposition method showed condylar head remodeling after mandibular set-back SSRO with rigid fixation. In skeletal class III patients, SSRO with rigid fixation resulted in rotation, diminution, and remodeling of the condylar head. However, these changes did not produce clinical signs or symptoms of temporomandibular disorders.

• 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 $(33.68{\pm}0.48){\times}(34.92{\pm}0.51){\times}(15.96{\pm}0.27){\times}(9.05{\pm}0.27)mm$.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.368-375
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• 2011

The aim of this study was to evaluate the position of the mandibular foramen in panoramic radiographs of Korean children to provide information for successful inferior alveolar nerve block anesthesia. 240 panoramic radiographs of 7 to 15-year-old boys and girls were analyzed. The subjects were divided into 4 groups in boys and girls according to their age.; 7-8, 9-10, 11-12 and 13-15 years old. The shortest distances from the center of the mandibular foramen to the anterior border of ramus, to the posterior border of ramus, to the antegonial notch and to the mandibular notch and the perpendicular distances from the center of the mandibular foramen to the occlusal plane were measured. The following results were obtained. 1) Although the relative position of the mandibular foramen in the ramus of mandible tended to move anteriorly for both genders with age, the vertical position did not correlate with age. 2) The mandibular foramen moved upward in relation to the occlusal plane with age, and showed statistically significant correlation with age(p<0.05). 3) The mandibular foramina of boys, when compared to those of girls, were located more superiorly in relation to the occlusal plane and more superiorly and posteriorly in the ramus of mandible.

• Imaging Science in Dentistry
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• v.51 no.3
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• pp.271-278
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• 2021

Purpose: This study aimed to investigate the panoramic imaging features of cleidocranial dysplasia (CCD) with a relatively large sample. Materials and Methods: The panoramic radiographs of 40 CCD patients who visited Seoul National University Dental Hospital between 2004 and 2018 were analyzed. Imaging features were recorded based on the consensus of 2 radiologists according to the following criteria: the number of supernumerary teeth and impacted teeth; the shape of the ascending ramus, condyle, coronoid process, sigmoid notch, antegonial notch, and hard palate; the mandibular midline suture; and the gonial angle. Results: The mean number of supernumerary teeth and impacted teeth were 6.1 and 8.3, respectively, and the supernumerary teeth and impacted teeth were concentrated in the anterior and premolar regions. Ramus parallelism was dominant (32 patients, 80.0%) and 5 patients (12.5%) showed a mandibular midline suture. The majority of mandibular condyles showed a rounded shape (61.2%), and most coronoid processes were triangular (43.8%) or round (37.5%). The mean gonial angle measured on panoramic radiographs was 122.6°. Conclusion: Panoramic radiographs were valuable for identifying the features of CCD and confirming the diagnosis. The presence of numerous supernumerary teeth and impacted teeth, especially in the anterior and premolar regions, and the characteristic shapes of the ramus, condyle, and coronoid process on panoramic radiographs may help to diagnose CCD.

• The korean journal of orthodontics
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• v.53 no.3
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• pp.185-193
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• 2023

Objective: The growth and development of the mandible strongly depend on modeling changes occurring at its ramus. Here, we investigated covariance patterns between the morphology of the ramus and the rest of the face. Methods: Lateral cephalograms of 159 adults (55 males and 104 females) with no history of orthodontic treatment were collected. Geometric morphometrics with sliding semi-landmarks was used. The covariance between the ramus and face was investigated using a two-block partial least squares analysis (PLS). Sexual dimorphism and allometry were also assessed. Results: Differences in the divergence of the face and anteroposterior relationship of the jaws accounted for 24.1% and 21.6% of shape variation in the sample, respectively. Shape variation was greater in the sagittal plane for males than for females (30.7% vs. 17.4%), whereas variation in the vertical plane was similar for both sexes (23.7% for males and 25.4% for females). Size-related allometric differences between the sexes accounted for the shape variation to a maximum of 6% regarding the face. Regarding the covariation between the shapes of the ramus and the rest of the face, wider and shorter rami were associated with a decreased lower anterior facial height as well as a prognathic mandible and maxilla (PLS 1, 45.5% of the covariance). Additionally, a more posteriorly inclined ramus in the lower region was correlated with a Class II pattern and flat mandibular plane. Conclusions: The width, height, and inclination of the ramus were correlated with facial shape changes in the vertical and sagittal planes.

• The korean journal of orthodontics
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• v.19 no.1 s.27
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• pp.77-93
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• 1989

The purpose of the present study were to disclose whether the depth of the mandibular antegonial notch can be used as an indicator of mandibular growth potential. The patients composed of 76 samples and were classified following 3 groups, based on the depth of mandibular antegonial notch : Deep notch group (more than 3mm), Neutral notch group (1-3mm), Shallow notch group (less than 1mm). For each case, the first lateral cephalograms were taken prior to the start of treatment and the second films 3-4 years after. The results were as follows; 1. Deep notch group had a shorter corpus, less ramus height and greater genial angle than did Shallow notch group. 2. Deep notch group had a more retrusive mandibular position than Shallow notch group. 3. Deep notch group had longer total anterior facial height and longer anterior lower facial height group. 4. Deep notch group grow vertical clockwise growth pattern, while Shallow notch group grow horizontal counterclockwise growth pattern. 5. Deep notch group had less mandibular growth than Shallow notch group during observation period.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.3
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• pp.193-203
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• 2001

Orthognathic surgery of the mandibular prognathism and the retrognathism is tend to be performed on the mandibular ramus to prevent inferor alveolar nerve injuries. The purpose of this study is to find a safe and accurate reference point on mandibular ramus for orthognathic surgery by comparative anatomical study of dentofacial deformity patients. We use 38 Korean Cadavers with normal occlusion(Group 1), 3-dimensional simulation of computerized tomogram of 23 patients with retrognathism (Group 2), 27 patients with mandibular prognathism (Group 3). Following results are obtained : 1. The maximum thickness of the mandibular ramus is $8.78{\pm}1.15mm$ for Group 2, $7.61{\pm}1.26mm$ for Group 1, $6.95{\pm}0.82mm$ for Group3 respectively (P=0001). The minimum thickness is $5.51{\pm}1.08mm$ for Group 1, $5.06{\pm}0.40mm$ for Group 2, $4.56{\pm}0.78mm$ for Group3, respectively (p=0.0001). But, the thickness at the level of 5mm above the lingular is $0.78{\pm}0.65mm$ for Group 2, $5.63{\pm}1.28mm$ for Group 1, $5.32{\pm}0.91mm$ for Group 3, respectively. There is no significant difference between these groups(P=0.0510). 2. The horizontal location from the midwaist point to lingular is $0.18{\pm}1.57mm$ for Group 1, $0.69{\pm}1.33mm$ for Group 2, $0.66{\pm}1.66mm$ for Group 3, and there is no significant difference between these groups(p=0.0835). But the vertical location from the midwaist point to lingular is $1.45{\pm}2.64mm$ for Group 1, $0.63{\pm}1.44mm$ for Group 2, $0.34{\pm}1.81mm$ for Group 3, and there is significant difference between these groups(p=0.0030). 3. The horizontal location from the midwaist point to mandibular foramen is $0.29{\pm}1.75mm$ for Group 1, $0.63{\pm}1.44mm$ for Group 2, $0.34{\pm}1.81mm$ for Group 3, and there is no significant difference between these groups(p=0.5403). But the vertical location from the midwaist point to mandibular foramen is $-3.33{\pm}4.43mm$ for Group1, $-4.79{\pm}2.26mm$ for Group 2, $-6.06{\pm}2.99mm$ for Group 3, and there is significant difference between these groups(P=0.0001). 4. The horizontal length from the disto-buccal cusp tip of mandibular second molar to lingula is $30.97{\pm}4.17mm$ for Group 3, $28.29{\pm}2.65mm$ for Group 1, $25.48{\pm}0.77mm$ for Group 2 (p=0.0000), and also vertical length is $7.72{\pm}3.22mm$ for Group 3, $6.38{\pm}1.83mm$ for Group 1, $5.89{\pm}2.30mm$ for Group 2 (P=0.0014). 5. The location of lingular is 0.50 from anterior border of mandibular ramus in all groups, if it assumed the length from anterior border to posterior border is 1. And it is almost 0.33 from the sigmoid notch, if it assumed the length from sigmoid notch to antegonial notch is 1. 6. In Group 1, Antilingular prominence is located on ($1.12{\pm}1.43mm,\;4.01{\pm}2.36mm$) from the midwaist point, and there is no correlation between antilingular prominence and lingular, mandibular foramen.

• The Journal of the Korean dental association
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• v.19 no.2 s.141
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• pp.181-185
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• 1981

In this study an attempt has been made to throw some light on the problem of the mandibular third molar on measurement made from 302 orthopantomograms of patients at the age of 8 to 20 years. The following conclusions were drawn on the basis of the present study. 1. The amount of growth from the lower first molar to the anterior border of the ramus from 8 years to 14 years was 7.9mm in the male and 7.5mm in the female. The growth from 15years 20 years was 4.5mm in the male and 2.6mm in the female. 2. The growth from the lower first molar to the posterior border of the ramus from 8 years to 14 years was 10mm in the male and 9.8mm in the female. The growth occurred after that was 5.8mm in the male and 2.0mm in the female. 3. The difference between A and C measurements for the various age groups remained fairly constant in the male and female.

• Journal of the korean academy of Pediatric Dentistry
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• v.6 no.1
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• pp.53-63
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• 1979

To Study the eruption pattern of the mandibular second permanent molar, the author took 425 cases of Oblique Cephalogram from 6 to 13 years old children and observed the vertical and mesiodistal directional change and tooth axis change. The following results were obtained. : 1. The eruption pattern of the mandibular second permanent molar was changed at about 10.0~10.1 ages or calcification stage IX. 2. At the early stage, the path of eruption of the mandibular second parmanent molar directed upward and forward and after calcification stage IX it changed to the direction of upward. 3. At the early stage, the distance from the distal end of the mandibular first permanent molar to the anterior portion of the ascending ramus was 0.9~1.0 times larger than the mesio-distal diameter of the mandibular second molar, but at the later stage it was increased 1.4 times larger than the mesio-distal diameter of the mandibular second permanent molar.

• 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.