• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.731-740
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• 1998

In the previous studies about prescription of preadjusted appliance, occlusal plane was used as a reference plane for crwon angulation (tip) measurement. But this reference plane is not parallel to the line connecting the facial axis points at which the centers of brackets are positioned (Andrews' plane), due to the curve of Spee. Therefore, we developed a new reference plane unaffected by the curve of Sun and more parallel to the Andrews' plane. It is an imaginary line connecting mesial and distal marginal ridges of each posterior tooth, and we named it 'marginal ridge plane'. In this study, crown angulations of posterior teeth of 29 normal occlusion samples were measured and measurements from both reference planes were compared. Crown angulation measurements measured from occlusal plane were different from crown angulation measurements from marginal ridge plane in the upper and lower 2nd molars (p<0.01), md 1st premolars (p<0.05). These results were analyzed as the crown angulation measurements from occlusal plane were affected by the curve of Spee. Crown angulations should be varied according to the amount of curve of Spee to maintain the continuity of marginal ridges. To solve this problem, determining bracket angulation as the bracket slot is parallel to the marginal ridge plane of each posterior teeth is recommended.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.601-609
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• 1998

The objects of this study were to analyze the crown angulation, crown inclination, molar offset angle, and crown in and out of the Korean adults having normal occlusion. 14 subjects (7 male, 7 female) were chosen in the 80 subjects who had ideal occlusion and beautiful profile we thought. The casts were obtained from the subjects, and then they were scanned with 3-dimensional scanner machine. We analyzed them with computer program based upon Andrews methods and the following results were obtained. 1. We got the norm of the crown angulation, crown inclination, molar offset angle, and crown in and out in the Korean adults. 2. The analysis using 3 dimensional scanner and computer program was more fast and accurate than the manual methods.

• Journal of Oral Medicine and Pain
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• v.19 no.2
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• pp.81-97
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• 1994

두개하악장애는 환자의 신체적 소인, 관련조직의 구조적 변화, 정신적 스트레스 등의 복합적 요인에 의 발생하는 다인성 질환으로 최근 대두되는 원인중의 하나가 신체, 특히 두경부의 자세이상이다. 비정상적인 두경부자세는 하악의 위치변화를 수반하여 종종 두개하악장애를 야기시키게 되나 이를 설명할 수 있는 과학적 증거는 아직 부족한 실정이다. 저자는 두경부 자세가 교합장치물에 의해 변화되는지를 저작근의 근전도학적 측면에서 규명하고자 21세에서 26세의 치과대학생으로 치아상실 및 교합간섭이 없고 두 개하악장애의 증후 및 경부운동제한을 가지지 않은 정상인 20명을 대상으로 각도계를 사용하여 시상면상에서 인위적으로 유도한 세 가지의 두경부자세변화 (0$^{\circ}$, 30$^{\circ}$ 굴절, 45$^{\circ}$ 신전)에 따른 교합안정장치의 장착(1시 간) 전후 및 안정위와 근접촉위(초기치아접촉위)에서의 두경부 근육(측두근, 교근, 악이복근)의 근전도를 Bioelectric Microprocessor EM2ⓡ를 사용하여 측정한 후 통계학적으로 비교, 분석, 평가하여 다음과 같은 결과를 얻었다. 1. 교합안정장치 장착전 하악 안정위 및 근접촉위에서 두부의 30$^{\circ}$굴절은 악이복근의 근활성도를, 45$^{\circ}$신전은 교근 및 악이복근의 근활성도를 증가시켰다.(p<0.05) 2. 교합안정장치 장착후 하악 안정위에서 두부의 30$^{\circ}$굴절은 악이복근의 근활성도를, 45$^{\circ}$신전은 교근 및 악이복근의 근활성도를 증가시켰으며, 하악 근접촉위에서 두부의 45$^{\circ}$신전은 악이복근의 근활성도를 증가시켰다(p<0.05). 3. 교합안정장치 장착 전후 및 두부의 30$^{\circ}$굴절, 45$^{\circ}$신전에 따른 측두군 및 교근의 하악 근접촉위에서의 근활성도가 안정위에서의 근활성도에 비해 유의한 증가를 나타냈다(p<0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.100-106
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• 2002

The prevalence of Class III malocclusion is approximately 5% in the Caucasian population, rising to as mush as 50% in the Japanese and Korean population. Recent studies have suggested than 63% of this malocclusion display maxillary retrusion. If left untreated, the malocclusion tends to worsen. Consequently, early treatment is commonly indicated to obtain a more normal jaw relationship. This report is 2 cases treated patients who diagnosed as skelectal Class III malocclusion due to deficient maxilla using facemask.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.649-656
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• 2005

The present study was designed to formulate cephalometric norms of normal occlusion for usage in orthodontic diagnosis of malocclusion in Korean children. Thirty two children, aged 4 to 6, with normal occlusion were chosen for this study, Sagittal and vertical relations were analyzed using lateral cephalogram and clinical photos and the measurements were compared with those of adults. On skeletal sagittal analysis, the mean values of the SNA and SNB angles were $83^{\circ}\;and\;78.72^{\circ}$. It showed that the mandible was retrognathic and retropositioned in comparison to those of adults. On skeletal vertical analysis, the mean values of the genial angle was $127^{\circ}$. This showed high angle pattern in children and reduction of genial angle due to counterclockwise rotation of the mandible is expected with growth. On soft tissue analysis, children showed convex pronto, obtuse nasolabial angle. On dental analysis, the mean values of the U1 to SN and IMPA were $91.04^{\circ}\;and\;86.57^{\circ}$. This showed retroclined upper and lower deciduous teeth in comparison to adults. For skeletal values, the liner values were generally greater in males than females.

• The korean journal of orthodontics
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• v.27 no.1
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• pp.35-44
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• 1997

mastication is basically regulated by central pattern regulalor(CPG) of brain system, target organ output from CPG is modulated by oral sensory feedback, anterior cross bite pattern infuluence the feedback mechanism and change muscle activity and jaw movement. The purpose of this study was to investigate differnce anterior cross bite group from normal group, the selected sample groups were 30 normal patient, 30 anterior cross bite patient. EMG and EGN of Biopak system were used for this study The following results were obtained 1 In resting slate of mandible, anterior cross-bite showed the higher muscle activities in all the muscle.(exception:left digastric muscle) than normal group. 2. In clenching state, No significant difference in muscle activities of normal group and anterior cross bite group was noticed 3. In swallowing state Normal group showed the higher muscle activities in left and right masseter muscle, right posterior temporal muscle. 4. In maximum opening and closing velocity, normal group showed the higher value than anterior cross-bite. 5. In the mean value of the maximum opening,the maximum anterior posterior movemenl from centric-occlusion, the lateral deviation from centric occclusion, normal group showed the higher value than anterior cross-bite group.

• Journal of Yeungnam Medical Science
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• v.7 no.2
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• pp.131-139
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• 1990

The purpose of this study was to assess the skeletal characteristics of the maxillofacial norms and the interpretation of craniofacial relations in korean adults by applying the Ricketts Analysis. The factors of the applied lateral cephalometric measurements were composed of the 10 factor analysis (Summary Analysis) and 7 internal structures to be suggested by Ricketts. Lateral cephalograms were obtained from 60 subjects over 21 years old, that consisted of 30 males and 30 females with normal occlusion, acceptable profile. The results were as follows : 1. The tables of means, standard deviations in each item and sex were made. 2. The author performed whether there was significance(P<0.05) between the registered male and female's measurement in each item..

• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.241-255
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• 2002

This study was performed to evaluate horizontal and vertical characteristics according to lateral cephalometry of adult Korean skeletal Class II patients using a selected horizontal and vortical reference planes of Koreans. 60 males and 60 females consisting of freshman of Yonsei University from 1996 to 1997 and patients with history of orthognatic surgery at the Dental Hospital of Yonsei University with a skeletal Class II profile were chosen and compared with 70 males and 70 females with normal occlusion. The skeletal Class R group had the following conditions : 1. Profile composed of a retrognathic mandible or protrusive maxilla; 2. Class II molar and canine key; 3. ANB-greater than $4^{\circ}; 4$. Wits appraisal-greater than 1.0mm; Cephalometric analysis consisted of 22 skeletal, 25 soft tissue, 12 dental measurements. The results were as follows. 1. There was no considerable vortical measurement difference between the skeletal Class II malocclusion group and the normal occlusion group in skeletal analysis. But, some variations were found between the two groups in soft tissue analysis. 2. Mandibular length of the skeletal Class II malocclusion group was smaller than that of the normal occlusion group. Mandible was more posteriorly positioned in the Class II malocclusion group than in the normal occlusion group. 3. The length and antero-posterior position of the maxilla were not different between the Class II malocclusion and the normal occlusion group. 4. The antero-posterior position of the nose, upper lip and maxillary soft tissue, and nasolabial angle were not different between the two groups. 5. Mandibular soft tissue of the Class H malocclusion group was more posteriorly positioned than that of the normal. 6. The vertical measurements of the incisors(U1-HP, L1-HP) were bigger in the Class II malocclusion group than in the normal, but those of the molars(U6-HP, U6-MP) showed no significant difference between the two groups. 7 Classifying the skeletal Class II malocclusion group according to the antero-posterior position of both jaws, normally positioned maxilla and retruded mandible was 43.3%, both normally positioned maxilla and mandible 28.3%, both retruded maxilla and mandible 20.0%..

• 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.

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.735-753
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• 1992

The purpose of this study was to analyze the positions of upper and lower incisors according to facioskeletal patterns. The lateral cephalometric radiographs of sixty persons with normal occlusion, forty persons with Class II Division 1 malocclusion, and forty persons with Class III malocclusion all above the age of 18, were analyzed. The following results were obtained. 1. C I angle, the measurement related to masticatory system, were $89.20{\pm}4.34^{\circ}$ in normal occlusion group, $81.68{\pm}士5.95^{\circ}$ in Class II Division 1 malocclusion group and $101.96{\pm}6.31^{\circ}$ in Class III malocclusion group. 2. In comparison with the positions of upper and lower incisors according to facioskeletal patterns, Class II Division 1 malocclusion group showed that upper incisors were different significantly in all measurements and inclined labially (P < 0.05). Lower incisors were different significantly in all measurements except LI-APog, LI-APog (mm), LI-AB, LI-AB (mm) and inclined labially (P < 0.05), Class III malocclusion group showed that upper incisors were different significantly in all measurements except UI-SN, UI-OP, and inclined labially (P < 0.05). Lower incisors were different significantly in all measurements and inclined lingually (P < 0.05). 3. In all facioakeletal patterns, LI-SN and LI-PH ware correlated moderately to facioskeletal measurements, and FMA was correlated moderately to measurements of lower incisor position. 4. Regardless of the facioskeletal patterns, the reference planes equally applicable were AB line in the measurements of upper incisor and APog line in the measurements of lower incisor.