• 대한치과보철학회지
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• 제39권2호
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• pp.171-183
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• 2001

The purpose of this study was compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the upper first molar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and were cemented with resin cement. The cemented crowns mounted on the testing jig were inclined 30 degrees and a universal testing machine was used to measure the fracture strength. The results of this study were as follows: 1. The fracture strength of the ceramic crown with 2.5mm depth and $8^{\circ}$ inclination was the highest (1393N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength (1015N) 2. There were no significant differences of the fracture strength according to occlusal depth and axial inclination. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth. 4. There was positive correlation between the fracture strength and the fracture surface area of crowns.

• 대한치과보철학회지
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• 제37권1호
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• pp.127-133
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• 1999

The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the upper first premolar. After 10 metal dies were made fir each group, the IPS Empress ceramic crowns were fabricated and each crown was cemented on each metal die with resin cement. The cemented crowns mounted on the testing jig were inclined 30 degrees and a universal testing machine was used to measure the fracture strength. The results were : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (630N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength(378N). There were no significant differences of the fracture strength by axial inclination in same occlusal depth group. 2. The fracture mode of the crowns was similar. Most of fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth.

• 대한치과보철학회지
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• 제41권1호
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• pp.48-60
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• 2003

The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the lower First Molar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and cemented with resin cement(Bistite resin cement, Tokuyama Soda Co. LTD., Japan). The cemented crowns were mounted on the testing jig with inclination of 30 degrees and the universal testing machine(Zwick Z020, Zwick, Germany)was used to measure the fracture strength. The results of this study were as follows : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (1789 N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength (1091 N). 2. There were no significant differences in the fracture strength by axial inclination of the same occlusal depth group. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth. Size of fragment was affected by the amount of occlusal reduction.

• 대한치과보철학회지
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• 제40권5호
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• pp.441-450
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• 2002

The purpose of this study was compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the lower second premolar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and cemented with resin cement. The cemented crowns were mounted on the testing jig with inclination of 30 degrees and the universal testing machine was used to measure the fracture strength. The results of this study were as follows : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (1284 N). Crowns of 1.5mm depth and $8^{\circ}$ inclination had the lowest strength (951 N). 2. There were no significant differences in the fracture strength by axial inclination of the same occlusal depth group. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth.

• 대한소아치과학회지
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• 제29권4호
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• pp.600-606
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• 2002

본 연구는 레이저 형광을 치아의 교합면에 적용하여 임상에서 초기 교합면 우식증의 감별에 레이저의 이용가능성을 평가하는데 그 목적이 있다. 아르곤 레이저 형광법의 교합면 우식증 탐지효과를 평가하기 위해 발거된 사람 치아 중에서 치아우식증을 제외한 결함이 없고 법랑질이 건강한 대구치와 소구치 50개를 선정하여 시진, 탐침을 이용한 시진, 아르곤 레이저 형광법을 이용해 관찰한 결과와 편광현미경으로 관찰한 병소의 깊이를 비교하여 다음과 같은 결론을 얻었다. 1. 교합면 우식의 조직학적 깊이와 아르곤 레이저 형광법에 의한 교합면 우식증 평가법과 시진, 탐침을 이용한 시진사이에서 모두 높은 상관 관계를 보였다. 2. 교합면 우식증의 조직학적 깊이와 각 검사법간의 일치도(kappa치)는 각각 시진이 0.189, 탐침을 이용한 시진이 0.128, 레이저 형광법이 0.472 이었으며, 레이저 형광법이 가장 일치도가 높았다. 이상의 결과를 종합해 보면 육안적 검사보다는 레이저 조사 후 관찰된 우식과 편광현미경상에서의 우식이 더 유의성 있는 관계를 보여 교합면 우식증탐지에의 레이저 형광법의 적용이 가능하리라 사료된다.

• 구강회복응용과학지
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• 제28권1호
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• pp.15-25
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• 2012

치주치료에 있어 교합치료의 타당성은 오래전부터 연구되어오고 있으나 아직도 논란이 많은 부분이다. 그 중에서도, 교합삭제를 이용한 수동적 정출(passive eruption)의 치료 효과에 대한 연구는 아직 보고된 바가 많지 않다. 본 연구의 목표는 교합삭제를 이용한 수동적 정출이 치주부착수준, 치주낭깊이 등의 치주임상지표들에 미치는 효과를 평가하는 것이다. 본 연구는 부산대학교 치과병원 치주과에서 중등도 치주염으로 치료받은 환자 중, 연구대상조건을 만족하는 16명의 환자, 40개의 치아를 대상으로 하였다. 연구 시작 단계에서 임의로 분류한 실험군과 대조군 치아 모두 임상적, 방사선적 검사를 시행하였다. 치석제거술과 치근활택술, 구강 위생 교육을 포함한 초기치료를 시행하고 4주 후 임상적, 방사선적 검사를 재실시하였다. 이 때 실험군은 교합면 삭제를 이용한 수동적 정출을 시행하고 대조군은 아무런 처치를 하지 않았다. 그 후 6개월 이후 임상적, 방사선적 검사를 재실시하였다. 그 결과 1)연구시작 단계와 비교 시, 초기치료에 의해 임상지표를 통한 치주조직의 염증상태가 개선되었으며, 2)실험군에서 치주낭깊이, 치아동요도, 치조골 소실 감소와 각화치은 폭경 증가가 더 큰 것으로 나타났다 (p<0.05). 이 결과로 볼 때, 초기치료와 함께 교합조정을 이용한 수동적 정출술이 치주치료에 도움을 줄 수 있을 것으로 사료된다.

• 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.

• Journal of Periodontal and Implant Science
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• 제34권3호
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• pp.647-657
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• 2004

A non-carious cervical lesion(NCCL) is the loss of tooth structure at the cementoenamel junction level that is unrelated to dental caries. This study was to evaluate the occlusal and periodontal status of teeth with non-carious cervical lesions. We evaluated 105 teeth with non-carious cervical lesions in 35 subjects aged 38-75 years and characterized them based on the shape and dimension, plaque retention, bleeding on probing(BOP), probing pocket depth(PPD), occlusal status, brushing type, hypersensitivity and wear facet. The results of this study were as follows 1. No significant association was observed between cervical lesions and occlusal contact in lateral excursions. 2. No significant difference occurred in plaque retention, PPD, BOP between teeth with and without cervical lesions. 3. Test teeth had a significantly higher percentage of hypersensitivity and occlusal wear facet than teeth without cervical lesions. 4. Wedge shaped lesions had a significantly higher percentage of plaque than saucer shaped lesions. 5. Teeth with plaque were found to have significantly deeper PPD than teeth without plaque retention in cervical regions. 6. Teeth with occlusal contacts were found to have significantly deeper PPD than teeth without occlusal contacts. 7. No significant association was observed between cervical lesions and PPD independent of plaque retention and occlusal contacts Although more knowledge is necessary, our results suggest that occlusal contact and bacterial plaque may influence on periodontal tissue, but NCCL is not directly associated with periodontal health

• 대한치과교정학회지
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• 제47권3호
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• pp.207-212
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• 2017

The popularity of clear overlay retainers (CORs) has increased recently because of their advantages such as better esthetics, cost effectiveness, easy fabrication, and good compliance. However, a deficiency in posterior occlusal settling is a reported limitation of CORs. The aim of this study was to evaluate the posterior occlusal contact changes in a new type of clear orthodontic retainer called Oral-treaper (OTP), which consists of three layers and has stronger mechanical characteristics than do conventional retainers. Three patients who completed fixed orthodontic treatment received OTP as a removable retainer. Cast models were fabricated after the removal of fixed appliances (T1) and after 4 to 11 months of using the retainers (T2). We evaluated all the cast models to compare the post-orthodontic settling pattern during the use of the OTPs. The depth of occlusal contacts was evaluated using color maps. The OTP did not prevent vertical settling in all patients but resulted in an improvement in posterior occlusal contact points.

• 대한치과의사협회지
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• 제17권7호통권122호
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• pp.521-524
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• 1979

The Author measured the position of the mandibular foramen with oblique cephalography in 41 8-aged, and 45 12-aged Korean children. The results of the studies were as follows; 1) The distance from the posterior occlusal plane to the mandibular foramen was 1.85±1.23mm. in age 8 and 1.85±1.21mm. in age 12 to the below. 2) The meeting point of the occlusal plane and anterior of the ramus to the mandibular foramen was 16.68±1.68mm. in age 8 and 16.84±2.09mm. in age 12. 3) the angulation between the occlusal plane and the line connecting the mandibular foramen and the meeting point of anterior of the ramus with occlusal plane was 8.15±1.87˚ in age 8 and 7.11±1.89˚ in age 12 to the below. 4) % depth was 53.98 ±3.40% in age 8 and 53.81±4.05% in age 12.