• Maxillofacial Plastic and Reconstructive Surgery
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• 제33권6호
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• pp.490-496
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• 2011

Purpose: Dr. Marquardt made the facial 'phi' mask using golden ratio. Most class III patients have bulky faces and want a smaller face. Using a facial golden mask, this study estimated and compared frontal photographs before and after operation for soft tissue measurement. The golden mask can be considered as a reference tool for facial esthetic analyses especially in lower face. Methods: Forty patients who had undergone orthognathic surgery at Samsung Medical Center from January 2006 to December 2009 were included in this study. These patients had Class III malocclusion. Lateral cephalometric radiographs, frontal clinical photos of pre-op and 8~12 month later post-op, and the facial 'phi' mask using golden ratio, were used for analysis. Reduction of the lower face area, occlusal plane changes, amounts of mandible setback and amounts of maxilla posterior impaction were estimated. Results: Lower facial reduction ratio and mandibular setback amounts were significantly different between 1-jaw and 2-jaw groups. Average postoperative changes in the area of lower face between bilateral sagittal split ramus osteotomy (BSSRO) and BSSRO combined maxilla posterior impaction were compared by using an independent simple t-test and $P$ value was 0.016. Therefore, the lower facial reduction ratio and mandibular setback amount were significantly different in maxilla posterior impaction. Conclusion: The two-jaw surgery group showed more reduction of the lower facial area than the 1-jaw surgery group. The amount of lower facial reduction was more related with the amount of mandibular setback. There was no significant relation in lower facial reduction with amount of maxilla posterior impaction, pre-op occlusal plane, post-op occlusal plane and the mandibular angle. A relationship between the change in the lower facial area and the amount of maxilla posterior impaction or the change of mandibular angle occlusal plane at pre-op could not be found because of the difference in the amount of setback between two groups.

• Restorative Dentistry and Endodontics
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• 제31권6호
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• pp.427-436
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• 2006

본 연구의 목적은 3차원유한요소분석법을 이용하여 정상 상악 제2소구치의 협측부의 응력분포에 다양한 교합응력이 미치는 영향을 평가하고자 하였다. 상악 제2소구치의 3차원유한요소모델을 형성한 후 형성된 모델에 3종류의 정적인 500N 점하중의 응력조건을 부여하였다. ANSYS 프로그램 (Swanson Analysis Systems, Inc., Houston, USA)으로 최대주응력과 최소주응력을 4개의 수평면 상(CEJ 상방 1 mm, CEJ 상방 0.5 mm, CEJ, CEJ 하방 0.5 mm)에서 분석하여 다음 결과를 얻었다. 1. peak stress가 협측 백악법랑경계를 따라 비대칭적인 모습으로 나타났다. 2. 압축응력 값은 법랑질의 압축파괴응력 범위 내에 있었지만 인장응력은 법랑질의 인장파괴응력 범위를 넘어섰다. 3. 비우식성치경부병소를 발생시키는 주요인은 설측교두의 협측경사면에 가해지는 교합압에 의한 인장응력이라고 보여진다.

• 구강회복응용과학지
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• 제33권4호
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• pp.314-320
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• 2017

상악 전치부 같은 심미성이 요구되는 부위의 치료 시에는 주위조직과 조화를 이루며 미소선, 연조직 및 경조직의 형태뿐아니라 치아의 해부학적 형태와 비율을 고려하여야 한다. 심미분석은 교합평면과 수평적 기준선간의 적절한 평행성을 평가하는 안면분석, 절치 절연부의 위치와 교합평면과 구각선 사이의 조화로움을 평가하는 치아입술분석, 심미성뿐만 아니라 적절한 기능을 위한 형태와 외형을 평가하는 치아분석, 치은 변연의 이상적인 윤곽을 형성하는 치은분석 등의 방법이 있다. 상악의 치간 이개는 체계적인 진단과 치료 계획을 통해서 심미적으로 수복할 수 있으며 교정, 보철, 보존적인 치료방법이 사용될 수 있다.

• 대한치과교정학회지
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• 제19권1호
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• pp.45-59
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• 1989

This study was undertaken to analyze the displacement and stress distribution in the mandible according to the pulling directions during mandibular first molar cervical traction after mandibular second molar extraction. The 3-dimensional finite element method(FEM) was used for a mathematical model composed of 594 elements and 1019 nodes. An orthodontic force, 450 gm, was applied to the each mandibular first molar in parallel, and below the occlusal plane by $7^{\circ}\;and\;25^{\circ}$ and meet the midsagittal plane by $40^{\circ}$ toward posterior direction. The results were as follows: 1. Mandibular teeth were displaced in more downward, posterior and lateral direction. Especially high stress was noted in case of parallel pull than in case of below the occlusal plane by $7^{\circ}\;and\;25^{\circ}$. 2. Mandibular first molar was moved bodily. 3. Generally, alveolar bone, mandibular body, ascending ramus and mandibular angle portion were displaced in downward, posterior and lateral direction. But coronoid process was displaced in downward, forward and lateral direction, and anterior and inner middle portion of condyle head and neck were displaced in downward, forward and medial direction, and posterior and outer middle portion of condyle head and neck were displaced in upward, forward and medial direction. 4. Maximum stress was observed at the condyle head and neck portion. With steeper direction of force, condyle head and neck showed more stress than parallel relation to the occlusal plane.

• The Journal of Advanced Prosthodontics
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• 제4권2호
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• pp.61-71
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• 2012

PURPOSE. To compare the changes in the occlusal vertical dimension, activity of masseter muscles and biting force after insertion of immediate denture constructed with conventional, tooth-supported and Implant-supported immediate mandibular complete denture. MATERIALS AND METHODS. Patients were selected and treatment was carried out with all the three different concepts i.e, immediate denture constructed with conventional (Group A), tooth-supported (Group B) and Implant-supported (Group C) immediate mandibular complete dentures. Parameters of evaluation and comparison were occlusal vertical dimension measured by radiograph (at three different time intervals), Masseter muscle electromyographic (EMG) measurement by EMG analysis (at three different positions of jaws) and bite force measured by force transducer (at two different time intervals). The obtained data were statistically analyzed by using ANOVA-F test at 5% level of significance. If the F test was significant, Least Significant Difference test was performed to test further significant differences between variables. RESULTS. Comparison between mean differences in occlusal vertical dimension for tested groups showed that it was only statistically significant at 1 year after immediate dentures insertion. Comparison between mean differences in wavelet packet coefficients of the electromyographic signals of masseter muscles for tested groups was not significant at rest position, but significant at initial contact position and maximum voluntary clench position. Comparison between mean differences in maximum biting force for tested groups was not statistically significant at 5% level of significance. CONCLUSION. Immediate complete overdentures whether tooth or implant supported prosthesis is recommended than totally mucosal supported prosthesis.

• 대한치과보철학회지
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• 제56권1호
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• pp.31-39
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• 2018

구치부 교합의 붕괴는 정상적인 교합평면을 소실 시키고, 과도한 마모를 일으켜 수직고경을 감소시킨다. 감소된 수직 고경은 심미적, 기능적 문제를 일으킬 뿐만 아니라 측두하악관절에 과하중을 야기하고 근신경계 이상을 일으킬 수 있다. 이렇게 붕괴된 교합관계를 개선하기 위해서 수직고경 변경을 고려하여야 하는데 치료 전 정확한 진단과 분석이 필수적이며 새로운 수직 고경에 대한 적응 평가를 함께 하여야 한다. 그리고 과도한 수직피개를 가지는 과개교합 환자는 치아 마모 및 치아정출의 교합 문제를 가지는 경우가 많다. 이러한 사항을 고려해 보았을 때 치아마모로 수직고경이 감소된 과개교합 환자의 문제 해결을 위해서는 전반적인 보철수복을 하여야 한다. 본 증례는 68세 남자환자로 다수 치아의 마모와 상악 구치의 결손부위를 치료하기 위해 수직고경 증가를 동반한 상악 가철성 국소의치 및 상하악 고정성 보철물로 수복한 증례이다.

• 대한치과보철학회지
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• 제56권4호
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• pp.302-307
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• 2018

다수의 치아 상실과 치아 마모로 인해 교합이 붕괴된 경우 교합 고경의 변경이 필요할 수 있다. 그리고 이러한 경우 심미적이면서도 근신경계와 조화를 이룰 수 있는 고경을 결정하는 것이 중요하다. 본 증례는 치아상실 및 마모로 인해 교합 수직 고경의 감소가 관찰된 환자에서 진단 모형과 방사선 사진 및 다양한 임상적 검사 등의 교합관계분석을 통해 교합 수직 고경을 회복을 동반한 보철 수복을 진행한 경우로, 기능적인 면과 심미적인 면에서 양호한 결과를 얻었기에 이를 보고하는 바이다.

• 구강회복응용과학지
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• 제30권4호
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• pp.339-349
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• 2014

상악과 하악의 크기부조화가 있거나 악간관계가 불안정한 환자의 치료목적은 안정적인 교합접촉을 부여하는 것이다. 중등도의 정신지체 환자로 부족한 수직고경, 수평적 악골관계 부조화, 광범위한 치질소실로 인하여 보철치료가 필요하였다. 두부계측학적 평균치를 기준으로 악골위치를 판별하고, 연조직 측모분석 후 수평 골삭제량을 결정하였다. 수술 부위의 안정적인 치유 및 설정된 상하악관계에 대한 의치 적응여부를 평가하였다. 만족할만한 심미성과 안정적 교합상태를 얻었으나, 추가적인 교합변화의 가능성을 고려한 정기적인 관리가 필요할 것으로 사료된다.

• 치과방사선
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• 제11권1호
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• pp.59-66
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• 1981

The dens evaginatus was a developmental variation which has arisen as a result of an evagination of inner enamel epithelium into the enamel organ. It has been given various. names by authors and was thought to be confined to Mongolian race. This study was performed to observe the incidence of dens evaginatus, and its ill-effects on the teeth and surrounding structures in 6356 Korean students and 10227 Korean adults. In plaster model, analysis was performed in accordance with forms and location of dens evaginatus on the. occlusal surface in the premolars. The pathologic changes caused by dens evaginatus were observed in paralleling periapical radiograms The results were as follows: 1. The prevalence of dens evaginatus in the student's group was 2.6%, and showed no sex predilection in the occurrence of evaginated teeth. 2. The sequence of dens evaginatus was in order of mandibular 2nd premolar, mandibular 1st premolar, maxillary 2nd premolar, and maxillary 1st premolar, respectively. 3. Of the cases with dens evaginatus, 73.5 % occured bilaterally. 4. The nipple form was the most frequent in respect of elevation of tubercle on the, occlusal surface. 5. In the base form of the tubercle, the occurrence of grooved form was the highest. 6. In the maxilla, those cases which the tubercle arose from the lingual ridge of the buccal cusp were most predominant. And in the mandible, those cases which the tubercle arose from the center of the occlusal surface were the most frequent. 7. The pulpal and periapical complications were shown in 24.4% of evaginated teeth in. periapical radiogram.

• Restorative Dentistry and Endodontics
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• 제19권1호
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• pp.231-254
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• 1994

Fracture of cusp, on posterior teeth, especially those carious or restored, is major cause of tooth loss. Inappropriate treatments, such as unnecessarily wide cavity preparations, increase the potential of further trauma and possible fracture of the remaining tooth structures. Fracture potential may be directly related to the stresses exerted upon the tooth during masticatory function. The purpose of this study is to evaluate the fracture resistance of tooth, restored with composite resin inlay. In this study, MOD inlay cavity prepared on maxillary first premolar and restored with composite resin inlay. Three dimensional finite element models with eight nodes isoparametric solid element, developed by serial grinding-photographing technique. These models have various occlusal isthmus and depth of cavity, 1/2, 1/3 and 1/4 of isthmus width and 0.7, 0.85 and 1.0 of depth of cavity. The magnitude of load was 474 N and 172 N as presented to maximal biting force and normal chewing force. These loads applied onto ridges of buccal and lingual cusp. These models analyzed with three dimensional finite element method. The results of this study were as follows : 1. There is no difference of displacement between width of occlusal isthmus and depth of cavity. 2. The stress concentrated at bucco-mesial comer, bucco-disal comer, pulpal line angle and the interface area between internal slopes of cusp and resin inlay. 3. The vector of stress direct to buccal and lingual side from center of cavity, to tooth surface going on to enamel. The magnitude of vector increase from occlusal surface to cervix. 4. The crack of tooth start interface area, between internal slop of buccal cusp and resin inlay. It progresses through buccopulpal line angle to cervix at buccomesial and buccodistal comer. 5. The influence with depth of cavity to fracture of tooth was more than width of isthmus. 6. It would be favorable to make the isthmus width narrower than a third of the intercuspal distance and depth of cavity is below 1 : 0.7.