• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.491-507
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• 2000

The purpose of this study was to investigate if there were a significant differences in mandibular position between cephalometric measurements from a centric occlusion tracing compared to those of a acquired centric relation by stabilization splint on malocclusion patient with TMD. 60 malocclusion patients, who had TMD and CO-CR discrepancy beyond normal range, were selected and subdivided into Class I, II, III by Angle's classification and also subdivided into clockwise, straight downward, and counterclockwise group by Jarabak's posterior facial height/anterior facial height ratio. Lateral cephaolmetric radiographs with the mandible in centric occlusion were taken and measured, and for each Patient the stabilization splint with mutually protected occlusal scheme was applied for minimum 3months. After each patient's CO-CR discrepancy was in normal range, lateral cephalometric radiographs were retaken and measured. The comparison of the difference between CO-CR cephalometric measurements in all sample, Class I, II, III groups, and Clockwise, Straight downward, Counterclockwise groups were studied. The finding of this study can be summarized as follows: 1 In all sample, the value of cephalometric measurements was significantly different between CO-CR. The mandible rotated to down and posterior position and the vertical change was greater than the horizontal change (overjet-1.3mm increase, overbite-1.9mm decrease). 2. In Class II malocclusion group, most of the mean difference value between CO-CR is higher than that of the other groups and more measurements was statically significant. 3. In clockwise and counterclockwise group, some of the mean difference value is higher than that of straight downward group and more measurements was statically significant. 4. There ware no measurements that explain centric relation measurements from the type of malocclusion, facial pattern and centric occlusion measurements. Henceforth, it is strongly recommended that stabilization splint therapy for orthodontic treatment on TMD patient should be excuted upon overall facial types prior to orthodontic diagnosis and treatment planning.

• The korean journal of orthodontics
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• v.24 no.1 s.44
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• pp.63-86
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• 1994

The purpose of this study was to find out some relationship between the positional change of mandible during treatment and the prognosis after treatment of ClassIII malocclusion. The patients selected for this study were sucessfully treated two patients, and three patients who wert also sucessful in active treatment but showed relapse during observation. Serial Cephalograms, photos, models, treatment record of these patients were analysed in each term of treatment and observation period. The results might be summarized as follows: The patient with swing back type in which mandible rotated posteroinferiorly during active treatment showed good dental md skeletal relationship during observation. Among the patients with Y-axis type, one who had harmonious growth between maxilla and mandible showed stable dental relationship during observation, the other who had not showed relapse. The swing back type was not changed during and after treatment but the patients who had Y-axis type were unchanged in some patients, and changed into forward type in the others. During active treatment, was lower facial height(ANS-Me) increased in all 5 patients, and in observation period the patients showing increase in lower facial height had stable occlusion but the others having decrease showed unstable dental relationship.

• Korean Journal of Cleft Lip And Palate
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• v.7 no.2
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• pp.77-91
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• 2004

본 연구의 목적은 반안면왜소증 환자의 하악골 신장술시 초기 치아골격 특성들 중에서 치료결과의 차이에 기여하는 인자를 찾는 것이다. 치료전의 치아골격 특성, 골신장술의 효과와 그 유지상태를 관찰하기 위하여 골신장술 직전(T0), 직후(T1), 추적 2년후(T2)에 측모와 정모 두부방사선 계측사진을 촬영하여 전후방, 수직치아, 비대칭 항목들을 계측하였다. T2 시기의 계측 결과에 따라서 환자들을 1군(양호군, 10명)과 2군(불량군, 9명)으로 분류하였다. 두 군에서 각 시기와 T0-T1, T1-T2 동안의 변화량의 차이를 Mann-Whitney U test, Wilcoxon signed independent t-test, rank test, ANOVA test를 사용하여 분석하였다. pruzansky type이 골신 장술의 성공과 실패 여부와 관계가 깊게 나타났다. T0 시기에 2군은 1군에 비하여 하악골이 후방위치되었고, 하악지 고경(ramus height)이 짧았고, 하악각(gonial angle)이 컸으며, 이환측 하악지가 내측경사되었고, 이환측으로의 이부변위(chin point deviation)가 크게 나타났다. 1군에서 골신장술의 주요한 효과는 하악지 고경의 증가, 하악골의 전방위치, 하악각의 증가, articular angle의 감소에 따른 하약골의 반시계방향 회전, 이환측의 하악지 경사의 증가, 교합면경사와 이부변위의 개선으로 나타났다. 그러나 2군에서는 골신장술을 시행했을 때 1군에 비하여 하악골이 시계방향으로 회전되었고 하악지 고경의 증가량이 작게 나타났다. T2 시기에 2군에서는 하악골의 반시계방향 회전이 나타났고, 하악지 성장이 일어나지 않았으나, 1군은 반대의 경향을 보였다. 이러한 인자들이 골신장술 결과의 차이에 기여하는 것으로 생각된다.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.175-183
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• 2000

The purpose of this study was to identify the compensatory adaptation of dentoalveolar structure according to the various skeletal relation through the statistical correlation between the anteroposterior, vertical skeletal and dentoalveolar relation. For this study, the sample were consisted of 101 adult subjects (51male and 50 female, mean age; male 23.6 years, female 21.5 years) who had good occlusion with the range of normal overjet and overbite and acceptable Angle's class I molar relationship which had not been related orthodontically The results were as follows : 1. Even though acceptable normal occlusion, the range of measurements which represent anteroposterior, vertical skeletal relation and dentoalveolar relation were very wide. 2. Upper and lower incisor axis were significantly correlated with anteroposterior skeletal relation, which means the mote lingual inclination of upper anterior teeth and the more labial inclination of lower anterior teeth according to the more anterior position of mandible to the maxilla (P<0.01). 3. Upper and 1ower anterior alveolar bone height was statistically correlated with the lower anterior vertical skeletal height. 4. Upper and 1ower alveolar bone height were not correlated with anteroposterior skeletal relation (P>0.05). 5. The correlation between the incisor axis and vertical skeletal was more closely related in upper anterior teeth than the lower anterior teeth. To summarize the above results, even though acceptable normal occlusion, skeletal and dentoalveolar relation was very widely ranged, and there were close relationship between the anteroposterior skeletal relation and the inclination of upper and lower anterior teeth and between the vertical skeletal relation and upper and lower anterior alveolar bone height. These finding can be concluded as compensatory adaptation to the different skeletal relationship.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.271-276
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• 2009

The aim of this study was to evaluate the effect of Bone Mineral Density(BMD) at mandible. So, we studied how to measure the BMD at mandible using DEXA(Dual energy X-ray absorptiometry, DEXA) by Horner er al (1996) and knew reproducibility of the measurements. Thirty-five patients (13 men, 22 women, mean age : 25.4 years) were examined using the GE Lunar Prodigy Advance(LUNAR Corporation, madison, USA). They were examined in Semiprone position of their body and true lateral position of their mandible selected the Lumbar lateral mode. We used the custom mode in analysis when ROI (area $30{\times}2.5\;mm^2$). Three ROIs ($30{\times}2.5\;mm^2$, $50{\times}2.5\;mm^2$, $20{\times}2.5\;mm^2$) were located each at the two different sites of the mandible (angle of mandible and mental symphysis) and BMD was measured. Differences in BMD measurement was statistically compared according to the size and location of ROI. BMD was $1.320{\pm}0.358g/cm^3$ in men and was $1.152{\pm}0.340g/cm^3$ in women. BMD at the angle of mandible was $1.201{\pm}0.361g/cm^3$ in men and was $1.025{\pm}0.377g/cm^3$ in women. BMD of men at the mental symphysis was $1.434{\pm}0.341g/cm^3$ and that of women was $1.19{\pm}0.358g/cm^3$. With the ROI of $20{\times}2.5\;mm^2$, BMD was $1.262{\pm}0.384g/cm^3$ in men and was $1.113{\pm}0.357g/cm^3$ in women. With the ROI of $50{\times}2.5\;mm^2$, BMD of men was $1.320{\pm}0.358g/cm^3$ and that of women was $1.129{\pm}0.340g/cm^3$. There was a statistically significant difference of BMD according to the size and location of ROI. When measuring mandible BMD, there are good for increasing ROI and locate between ramus and mental symphysis. Especially following exam, refer to same size and location with fore exam. According to study which measure mandible BMD, It's correct to measure better a portion of mandible then whole of BMD. Using DEXA protocol is studied good for the additional study to compare the BMD at mandible. Later date, It will be good for measurement value in implant and bone graft quantitatively. Using DEXA method gain BMD threshold value in korean.

• The Journal of the Korean dental association
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• v.13 no.10
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• pp.941-946
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• 1975

치과교정학 분야에 있어서 부정교합자의 다양한 하악골 위치변화에 따른 Hyoid bone 위치변화에 대한 연구는 부족한 감이 있어, 저자등은 Hellman의 치령ⅢA 이후의 부정교합을 가진 남ㆍ녀 97명을 Angle씨 각급 부정교합의 분류에 의해 중심교합위와 안정위시의 두부 X선 사진을 가각 탐득하고 Hyoid bone의 위치변화를 측정하여 다름과 같이 결과를 얻었다. 1. 중심교합위에서의 Cranial base에 대한 Hyoid bone 위치변화에서는 Angle씨 ClassⅢ에서 남ㆍ녀 모두 물징적으로 전방에 위치하며, Mandibular plane에 대한 Hyoid bone위치변화에서는 각급 부정교합사이에 특기할 차이가 없다. 2. 안정위에서의 Hyoid bone위치는 중심교합위에서의 위치와 비슷한 분포를 나타내고 있다. 3. 중심교합위에서는 안정위로싀 위치변화에서 각급 부정교합 똑같이 후ㆍ하방 이동을 나타내고 있다.

• The korean journal of orthodontics
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• v.33 no.1 s.96
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• pp.41-49
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• 2003

This study examined the relations between degree of posterior dental compensation and skeletal discrepancy in Class III malocclusion. The pretreatment lateral cephalogras and dental casts of 87 skeletal Class III adults were selected to provide a random sampling of skeletal Class III malocclusion. Skeletal discrepancy was described with ANB angle, Wits appraisal, SN-Mn plane angle, FMA and ratios of basal arch width. Degree of posterior dental compensation was described with maxillary intermolar angle, mandibular interolar angle and sum of intermoloar angle. The relationships between skeletal discrepancy and degree of posterior dental compensation were analyzed with simple correlation analysis, stepwise multiple regression analysis. The results were as follows 1. A strong association was found between the variation in the anteroposterior measure, ANB angle and the variation of posterior dental compensation measures, sum of intermolar angle and mandibular intermolar angle in skeletal Class III malocclusion. 2. There was no statistically significant relationship between the variation in the vertical measures and the variation of posterior dental compensation measures in skeletal Class III malocclusion. 3. There was no statistically significant relationship between the variation in the anteroposterior and vortical measures and degree of basal arch width discrepancy.

• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.320-329
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• 2005

The three-dimensional (3D) changes of bone, soft tissue and the ratio of soft tissue to bony movement was investigated in 8 skeletal Class III patients treated by mandibular setback surgery. CT scans of each patient at pre- and post-operative states were taken. Each scan was segmented by a threshold value and registered to a universal three-dimensional coordinate system, consisting of an FH plane, a mid-sagittal plane, and a coronal plane defined by PNS. In the study, the grid parallel to the coronal plane was proposed for the comparison of the changes. The bone or soft tissue was intersected by the projected line from each point on the gird. The coordinate values of intersected point were measured and compared between the pre- and post-operative models. The facial surface changes after setback surgery occurred not only in the mandible, but also in the mouth corner region. The soft tissue changes of the mandibular area were measured relatively by the proportional ratios to the bone changes. The ratios at the mid-sagittal plane were $77\~102\%(p<0.05)$. The ratios at all other sagittal planes had similar patterns to the mid-sagittal plane, but with decreased values. And, the changes in the maxillary region were calculated as a ratio, relative to the movement of a point representing a mandibular movement. When B point was used as a representative point, the ratios were $14\~29\%$, and when Pog was used, the ratios were $17\~37\%(9<0.05)$. In case of the 83rd point of the grid, the ratios were $11\~22\%(p<0.05)$.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.733-741
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• 1997

As a result of surgical orthodontic treatment of mandibular prognathism, changes take place in the skeletal and soft orofacial components. Although some investigators had stated that permanent reduction of airway space was observed after mandibular setback surgery, it was not clear that this permanent reduction was sustained during long-term follow-up. The purpose of this study was to assess the changes in oropharyngeal airway space and soft tissue orofacial component following the mandibular setback surgery and during the follow-up period. The correlation between the changes of the oropharyngeal airway space and the changes of other soft tissue orofacial component was also assessed. The findings of this study were as follows ; 1. The oropharyngeal airway space area decreased following mandibular setback surgery for mandibular prognathism and continued to decrease during the follow-up period(p<0.05). 2. The pharyngeal depth at Xi point level and the 2nd cervical vertebra point level decreased after the surgery and remained during the follow-up period(p<0.05). The decrease of these pharyngeal depth was correlated with the decrease of oropharyngeal airway space area(p<0.01). 3. The decrease of pharyngeal depth at the 3rd and 4th cervical vertebra point level was not significant after the surgery and during the follow up period. 4. The hyoid bone moved downward after the surgery(p<0.05), but returned to its original position during the follow-up period. 5. The length & height of tongue and the Position of epiglottis base did not change significantly(p>0.05). 6. The soft palate was displaced posteriorly after the surgery and remained to its changed position during the follow-up period(p<0.05) due to posterior displacement of tongue. The changes of soft palate were significantly correlated with the decrease of oropharyngeal airway space area(p<0.01). 7. The narrowing of oropharyngeal airway space was due to the posterior displacement of tongue above the level of epiglottis tip. The posterior displacement of tongue following mandibular setback osteotomy remained during the follow-up period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.191-200
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• 1998

This study was intended to perform the influence of condyle positional change after surgical correction of skeletal Class III malocclusion after orthognathic surgery in 37 patients(male 13, female 24) using computed tomogram that were taken in centric occlusion before, immediate after, and long term after surgery and lateral cephalogram that were taken in centric occlusion before, 7 days within the period of intermaxillary fixation, at the 24 hours later removing intermaxillary fixation and long term after surgery. 1. Mean intercondylar distance was $84.42{\pm}5.30mm$ and horizontal long axis of condylar angle was $12.79{\pm}4.92^{\circ}$ on the right, $13.53{\pm}5.56^{\circ}$ on the left side. Condylar lateral poles were located about 12mm and medial poles about 7mm away from the reference line(AA') on the axial tomogram. Mean intercondylar distance was $83.15{\pm}4.62mm$ and vertical axis angle of condylar angle was $76.28{\pm}428^{\circ}$ on the right, $78.30{\pm}3.79^{\circ}$ on the left. 2. In amount of set back, We found the condylar change(T2C-T1C) which had increasing tendency in group III (amount of setback : 10-15mm). but there was no statistical significance(p>0.05). 3. There was some correlation between condylar change(T2C-T1C) and TMJ dysfunction. It seemed that postoperative condylar change had influenced postoperative TMJ dysfunction, through there was no statistical significance (p>0.05). As we have observed the change of condylar axis in the group that complained of TMJ dysfunction in cases of large amount of mandibular setback. So we consider that the more trying to conserve condylar position will decrease occurrence rate of post operational TMJ dysfunction.