• Journal of Oral Medicine and Pain
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• 제9권1호
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• pp.77-92
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• 1984

The purpose of this study was to investigate the relationship between the mandibular positions and the habitual mandibular opening and closing movements in normal subject using the newly developed electric mandibular movement analyzing device(Saphon Visi-Trainer C-II.Tokyo Shizaisha Inc. Tokyo, Japan) One of the cause of the temporomandibular joint dysfunction has been considered abnormal mandibular positions especially the abnormal deviation between intercuspal position from retruded contact position. The subjects in this study were consisted of 55 young adults in 20 decade who had normal occlusion, no prosthodontic restorations and no history of disturbance or pain on temporomandibular joint and masticatory muscles. The results were as follows : 1. The deviations of intercuspal position from retruded contact position were 0.23mm in frontal view and 1.02mm in sagirral view. 2. The larger the deviation of intercuspal position from the retruded contact position, the higher the proportion of uncoincidence of the habitual nandibular closing and opening trajectories was, and the proportion was higher in sagittal view than frontal view, 10mm opening than 5mm opening. 3. Correlation between the deviation of intercuspal position from retruded contact position and uncoincidence rate of the habitual mandibular closing and opening trajectories was higher in frontal view than sagittal view.

• 대한치과교정학회지
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• 제53권6호
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• pp.402-419
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• 2023

Objective: This study assessed the differences in soft tissue deviations of the nose, lips, and chin between different mandibular asymmetry types in Class III patients. Methods: Cone-beam computed tomography data from 90 Class III patients with moderate-to-severe facial asymmetry were investigated. The sample was divided into three groups based on the extent of mandibular rolling, yawing, and translation. Soft tissue landmarks on the nose, lips, and chin were investigated vertically, transversely, and anteroposteriorly. A paired t test was performed to compare variables between the deviated (Dv) and nondeviated (NDv) sides, and one-way analysis of variance with Tukey's post-hoc test was performed for intergroup comparisons. Pearson's correlation coefficient was calculated to assess the relationship between the soft and hard tissue deviations. Results: The roll-dominant group showed significantly greater differences in the vertical positions of the soft tissue landmarks between the Dv and NDv than other groups (P < 0.05), whereas the yaw-dominant group exhibited larger differences in the transverse and anteroposterior directions (P < 0.05). Moreover, transverse lip cant was correlated with the menton (Me) deviation and mandibular rolling in the roll-dominant group (P < 0.001); the angulation of the nasal bridge or philtrum was correlated with the Me deviation and mandibular yawing in the yaw-dominant group (P < 0.01). Conclusions: The three-dimensional deviations of facial soft tissue differed based on the mandibular asymmetry types in Class III patients with similar amounts of Me deviation. A precise understanding of soft tissue deviation in each asymmetry type would help achieve satisfactory facial esthetics.

• 대한치과교정학회지
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• 제45권4호
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• pp.153-163
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• 2015

Objective: The purpose of this study was to assess rotational patterns of dentofacial structures according to different vertical skeletal patterns by cone-beam computed tomography (CBCT) and analyze their influence on menton deviation in skeletal Class III deformity with mandibular asymmetry. Methods: The control group consisted of 30 young adults (15 men, 15 women) without any severe skeletal deformity. The asymmetry group included 55 adults (28 men, 27 women) with skeletal Class III deformity and at least 3-mm menton deviation from the midsagittal plane; it was divided into the hyperdivergent and hypodivergent subgroups using a mandibular plane angle cutoff of $35^{\circ}$. Fourteen rotational variables of the dental arches and mandible were measured and compared among the groups. Correlations between menton deviation and the other variables were evaluated. Results: The asymmetry group showed significantly larger measurements of roll and yaw in the mandible than the control group. The hypodivergent subgroup showed significant differences in maxillary posterior measurements of yaw (p < 0.01) and maxillary anterior shift (p < 0.05) compared with the hyperdivergent subgroup. All the mandibular measurements had significant correlations with menton deviation (p < 0.01). Most measurements of roll were positively correlated with one another (p < 0.01). Measurements of yaw and roll in the posterior regions were also positively correlated (p < 0.05). Conclusions: Menton deviation in skeletal Class III deformity with mandibular asymmetry is influenced by rotation of mandibular posterior dentofacial structures. The rotational patterns vary slightly according to the vertical skeletal pattern.

• The Journal of Advanced Prosthodontics
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• 제3권3호
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• pp.172-176
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• 2011

Surgical resection of the mandible due to presence of benign or malignant tumor is the most common cause of the mandibular deviation. Depending upon the location and extent of the tumor in the mandible, various surgical treatment modalities like marginal, segmental, hemi, subtotal, or total mandibulectomy can be performed. The clinicians must wait for extensive period of time for completion of healing and acceptance of the osseous graft before considering the definitive prosthesis. During this initial healing period prosthodontic intervention is required for preventing the mandibular deviation. This case report describes early prosthodontic management of a patient who has undergone a reconstructed hemi-mandibulectomy with modified mandibular guide flange prosthesis. The prosthesis helps patient moving the mandible normally without deviation during functions like speech and mastication.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권4호
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• pp.594-606
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• 1996

저자는 하악골의 측방 변위를 보이는 악안면 비대칭증례에서 이하두정방사선규격사진과 정모두부방사선규격사진을 이용하여 두개부 형태와 악안면부의 비대칭성과의 상호 관련성을 조사하여 다음과 같은 결론을 얻었다. 1. 이하두정방사선규격사진에서 하악골의 편위정도는 평균 $-3.12{\pm}3.80$ 이며 절대치의 평균은 $2.50{\pm}2.82$ 이였다. 2. 이하두정방사선규격사진에서 비편위측과 편위측에 대한 유의성 검정에서 통계적인 유의성은 없었으나(p>0.05), 그 차이의 평균은 전두부(Y10, Y9, Y8, Y7, Y6)에서는 편위측이 상대적으로 더 크고, 측두부(Y5, Y-1, Y-2, Y-3, Y-4, Y-5, Y-6)에서는 비편위측이 상대적으로 더 크게 나타났다. 3. 정모두부방사선규격사진에서 술전의 하악골의 평균 편위는 $1.3983{\pm}3.521$ 이며 절대치의 평균은 $3.95{\pm}2.85$ 이였다. 4. 정모두부방사선규격사진에서 수술에 의한 변화량 (PT2A-PT1A) 에 대한 재발량(PTLA-PT2A)의 상관관계분석에서 수술에 의한 이동량이 많을 수록 재발이 많은 것으로 나타났다(p<0.05). 5. 이하두정방사선규격사진에서 하악골 편위정도에 대하여 두개관 형태(비변위-변위차이)에 대한 상관관계분석에서 통계적인 유의성은 없었으나(P>0.05), 변위가 클수록 전두부에서는 비변위측이, 후두부에서는 변위측이 더 큰 경향을 보였다. 6. 정모두부방사선사진상에서 하악골의 변위 정도에 대한 두개관(비변위-변위)과의 상관관계 분석에서 Y4(P<0.05), Y3, Y2, Yl, 0, Y-1, Y-2, Y-4, Y-6(P<0,01), Y-5(p<0.001) 등의 위치에서 하악골의 변위 정도가 클수록 비변위측이 더 큰 것으로 나타났다. 7. 정모두부방사선사진상에서 하악골 재발에 대한 두개관(비변위-변위)과의 상관관계분석에서는 통계적인 유의성이 없었으나(P>0.05), 측두부에서는 비변위-변위 차이가 클수록 재발이 많은 경향을 보였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권2호
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• pp.151-159
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• 2005

The purpose of this study was to evaluate the nasal deviation in mandibular prognathism with mandibulo-facial asymmetry. There were 40 patients whose mandibular prognathism with/without facial asymmetry were treated with orthognathic surgery from March 2002 to October 2003. The Group A(n=20) had a mandibulo-facial asymmetry over 6mm menton deviation in cephalogram PA and the Group B(n=20) had a mandibular prognathism. The preoperative frontal photograph, cephalogram PA and three dimensionalcomputed tomography(divided in hard tissuse image and soft tissue image) of two group was evaluated NDA(nasal deviation angle) and MDA(mandibular deviation angle). The NDA was statistical difference between asymmetry Group A and symmetry Group B(p<0.01), and was deviated in affected side of asymmetry. The MDA were also statistical difference between Group A and Group B(p<0.01), however the measurements of MDA between the frontal photograph, 3D-CT and cephalogram PA were similar to each others. The low correlation of NDA between frontal photograph and cephalogram PA in Group A and B demonstrate that we couldn't assess nasal deviation in cephalogram PA. It could be concluded that patients with mandibulo-facial asymmetry have a nasal deviation and clinician must remember this fact when they assess and treat patients.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.57.1-57.8
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• 2019

Background: The relationship between the lateral deviation of chin and the upper and middle facial third asymmetry is still controversial. The purpose of this study is to evaluate the correlation of upper and middle facial third asymmetry with lateral deviation of chin using 3-dimensional computed tomography. The study was conducted on patients who underwent orthognathic surgery from January 2016 to August 2017. A total of 40 patients were included in this retrospective study. A spiral scanner was used to obtain the 3-dimensional computed tomography scans. The landmarks were assigned on the reconstructed 3-dimensional images, and their locations were verified on the axial, midsagittal, and coronal slices. The Pearson correlation analysis was performed to evaluate the correlation between chin deviation and difference between the measurements of distances in paired craniofacial structures. Statistical analysis was performed at a significance level of 5%. Results: In mandible, the degree of chin deviation was correlated with the mandibular length and mandibular body length. Mandibular length and mandibular body length are shorter on the deviated-chin side compared to that on the non-deviated side (mandibular length, r = -0.897, p value < 0.001; mandibular body length, r = -0.318, p value = 0.045). In the upper and middle facial thirds, the degree of chin deviation was correlated with the vertical asymmetry of the glenoid fossa and zygonion. Glenoid fossa and zygonion are superior on the deviated-chin side than on the non-deviated side (glenoid fossa, r = 0.317, p value = 0.046; zygonion, r = 0.357, p value = 0.024). Conclusion: Lateral deviation of chin is correlated with upper and middle facial third asymmetry as well as lower facial third asymmetry. As a result, treatment planning in patients with chin deviation should involve a careful evaluation of the asymmetry of the upper and middle facial thirds to ensure complete patient satisfaction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제29권3호
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• pp.173-181
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• 2003

Purpose : This study was intended to evaluate the positional relationship between the hyoid bone and the mandible in patients with mandibular protrusion after mandibular set-back surgery by means of 3D-CT. Materials and methods : Preoperative(3 weeks before) and postoperative (6 weeks after) 3D-CT & cephalogram were taken on 32 patients(12 male, 20 female, mean age of 23.2) treated by bilateral sagittal split osteotomy with rigid fixation. The angular measurement on 3D-CT basilar view were deviation of Me & H, long axis angle of left & right cornu majus. The lineal measurement on 3D-CT basilar view were composed of intercondylar line and coordinates(x,y) of Me & H. The angular & lineal measurement of lateral cephalogram were composed of mandibular plane angle, SNA, SNB, ANB, FH-NA & FH-NB, and coordinates(x,y) of B, Pog, Me & H, PAS, Lpw, MPH and IAS. On the frontal cephalogram, deviation of Me were evaluated. Results : The mean mandibular set-back was 8.0mm horizontally and mandibular plane angle was slightly increased. The hyoid bone was displaced postero-inferiorly, the distance between MP(mandibular plane) and H(hyoid bone) was increased and the posterior airway space values (PAS, Lpw, IAS) were decreased. The coordinates Me(x,y), H(x,y) and deviation angle Me'& H' were revealed the strong positive correlation. Conclusion : The results revealed that the horizontal, vertical and transverse relationship of the mandibular and the hyoid bone movements were significantly correlated in patients performed mandibular set-back surgery.

• 턱관절균형의학회지
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• 제12권1호
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• pp.1-6
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• 2022

Objectives: For the deviation phenomenon occurring during the treatment process in temporo-mandibular balancing medicine (TBM), hypotheses were established regarding the cause and mechanism of formation from the perspective of neuro-science and material mechanics, and a verification method was proposed. Methods: The deviation phenomenon was theoretically analyzed based on the structure theories of material mechanics of the joint and the neurological pain mechanism. Results: Deviation occurs due to temporary yield by the accumulation of heterogeneous stress in the temporo-mandibular joint and the affected joint. Because the joint structures are corresponding with material mechanics showing compressive and tensile properties. The size of the deviation is expressed in terms of strain. The occlusal surface of the teeth is level with the axial joint. Since the magnitude of the deviation has a proportional relationship with the degree of abnormality of the temporo-mandibular joint, the magnitude of the deviation calculated by the balance measurement can be replaced by the strain. The major variables involved in the occurrence of deviations are the strength of joint structures and neurological conditions. Therefore plastic deformation and adaptation occur as a long-term depression of neural circuits is strengthened in different ways at different locations each time in various clinical situations. This is the reason why the sequence of the restoration process while correcting deviations is following reverse order of the accumulation in many layers in the muscular nervous system. Conclusions: From the above results, it can be inferred that the occurrence and correction of the deviations are corresponding with the plastic deformation and neuro-plasticity.

• 대한치과교정학회지
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• 제48권2호
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• pp.73-80
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• 2018

Objective: This retrospective study compared the three-dimensional (3D) structure of mandibular condyles between adults with and without facial asymmetry, and whether it influences menton deviation. Methods: Sixty adult patients were classified into symmetry and asymmetry groups based on the menton deviation on postero-anterior radiographs. The right/left differences of 3D measurements were compared between the two groups, and measurements were compared separately on the right and left sides. The correlations between menton deviation and the right/left differences were analyzed. Results: The mediolateral dimension, neck length, condylar angles to the anteroposterior reference (PO) and midsagittal reference planes, and neck and head volumes showed significantly larger right/left differences in the asymmetry group compared to the symmetry group. Separate comparisons of the right and left sides between the two groups showed that the neck was significantly shorter and neck and head volumes were significantly smaller on the left side, which was deviated side in the asymmetry group. Pearson's correlation analysis showed significant positive correlations of menton deviation with right/left differences in neck length, condylar angle to the PO plane, and neck and head volumes in the asymmetry group. Conclusions: In individuals with facial asymmetry, menton deviation is associated with the right/left differences caused by a smaller condyle on the deviated side, particularly in neck length and neck and head volumes.