• 대한치과보철학회지
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• 제18권1호
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• pp.7-13
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• 1980

The purpose of this study was to evaluate the removable partial denture prescriptions including surveyed crowns and design of component parts sent to the laboratory technician. A total of 351 casess with prescription forms and master cast in maxillary and mandibular semi-edentulous situations collected from dental laboratory by random sampling were selected for this study. The evaluation and study observed here involved the classification of edentulous situations, status of abutment splinting, form of rest seats and guiding plane of surveyed crows, location of maxillary major connectors and tripodig marks on the master casts. Removable partial denture prescriptions contained (1) general request (upper and lower cast framework), (2) types of metal, (3) location of retainer(retention, lingual bracing, rest area, guiding plane surface), (4) location and type of major connector, (5) relief area and amount, (6) and other specific instructions. The following informations based on the classified groups such as Group I was those cases sent with no real prescriptions. They say 'make a partial.' No prescriptions, no thought beforehand, Group II was those cases sent with a minimal prescriptions. They say 'make a partial with clasps on May be some preparations, usually inadequate. Group III was those cases sent with a moderately good prescription. Adequate but could be much better. No tripoding but it tell what clasps go where. Still not good prescriptions. Group IV was good cases, tripoded with adequate prescriptions and a prescription which exactly describes what is expected from the laboratory. The analyzed results were as follows: 1. The normal form of rest seats and guiding plane of surveyed crowns in Class. I and Class. II edentulous situations on the maxillary cast were observed 31.9% and 27.89%, respectively. The abutment teeth and retainer without occlusal rests of Class. I and Class. II were showed 11.58% and 8.86%, respectively. In mandibular cases, the normal form of rest seats and guiding plane of surveyed crowns showed 27.54% and 8.82% in Class. I and Class. II situation. The abutment teeth and retainer without rest seats were showed 15.19%, respectively. 2. The splinted surveyed crowns of Class. I and Class. II maxillary edentulous situations in distal extension cases were showed 34.51% and 28.85%, but 28.52% and 10.29%, respectively. 3. The location and type of maxillary major connector delineated on the master cast were 66 cases (44.89%). 4. The results of 351 cases were classified as Group I 146(41.59%), Group II 115 (32.76%), Group III 57 (16.23%), and Group IV 33 (9.48%). 5. The delineation of abutment tooth for clasping were 176 cases (50.14%) among total of 351 cases. 6. The delineation of height of contour line were showed 45 cases (12.8%) in Group II, 14 cases (3.98%) in Group III and 33 cases (9.40%) in Group IV with total 92 cases (26.21%). 7. In surveying procedure, the delineation of tripoding marks and reference line were showed 17 cases (4.84%).

• 대한치과보철학회지
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• 제34권3호
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• pp.415-430
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• 1996

하악좌측 제1대구치와 하악 좌측 제2대구치, 하악우측 제2소구치를 주지대치로 사용하고 하악우측 제1대구치와 하악 우측 제2대구치가 상실된 Kennedy 분류 II급 후방연장 국소의치에서 하악좌측 측절치에 incisal hook rest를 간접유지장치로 가지는 경운(Model I), 하악좌측 견치에 cingulum rest를 간접유지장치로 가지는 경우(Model II), 하악좌측 제1소구치에 근심교합면 레스트를 간접유지장치로 가지는 경우(Model III)의 모형에서, 상실된 하악우측제2대구치의 원심 변연융선에 해당하는 부위에 고리를 형성하여 교합평면에서 전상방 $45^{\circ}$ 각도로 860gm의 이탈력을 가하여 간접유지장치가 장착된 지대치와 양쪽 인접치 주위조직에 발생하는 응력을 비교분석한 바 다음과 같은 결론를 얻었다. 3가지 모형 모두에서 지대치의 치근단 부위보다는 치경부의 협측부위와 근원심 부위에 압축응력이 나타났다. 지대치의 설측 치경부에는 3가지 모형 모두에서 약한 인장응력이 나타났다. 협측부위의 압축응력의 크기는 Model I이 가장 컸고, Model II, Model III순으로 나타났다. Model I과 Model II에서 지대치의 근심과 원심 치경부에 압축응력이 나타났으며, 압축응력의 크기는 Model I이 Model II보다 더 컸다. Model III에서는 지대치의 근심치경부에서만 압축응력이 나타났다. 전반적으로 압축응력의 크기는 Model I이 가장 컸고, Model II, Model III의 순으로 나타났다.

• 대한치과보철학회지
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• 제37권5호
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• pp.581-596
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• 1999

하악 우측 제1대구치 및 제2대구치가 손실된 2급하악 후방연장 국소의치에서 무치악 부위 지대치 유도면의 기울기와 형태가 지지조직에 미치는 응력 및 변위를 비교 분석하기 위하여 3차원 유한요소법을 이용하여 알아보았다. Kratochvil 형태의 유도면의 기울기가 잔존치조제에 대하여 $90^{\circ}$인 경우, $95^{\circ}$인 경우, 그리고 $100^{\circ}$인 경우와 Krol형태의 유도면의 기울기가 $90^{\circ}$인 경우에 있어서 제2소구치를 지대치로 하고 RPI형태의 유지장치를 사용하는 경우를 가정하여 모델링한 다음 제1대구치 및 제2대구치의 중심와에 150N의 하중을 가하여 응력 및 변위에 대하여 실험한 결과 다음과 같은 결론을 얻었다. 1. Kratochvil의 유도면 형태 중 기울기가 $90^{\circ}$인 경우와 Krol의 유도면 형태에서는 유사한 응력 분포를 나타내었으며 특히 지대치에서 치근단 방향으로 응력이 향하는 것으로 나타났다. 2. 유도면의 기울기가 $95^{\circ}$인 경우에서는 지대치의 치근단 부위에 응력이 증가하면서 근심방향으로 향하였으며, $100^{\circ}$인 경우에서는 치근단의 응력이 협측 및 근협측 방향으로 집중되어 나타났다. 3. 유도면의 기울기가 $90^{\circ}$인 경우에서는 지대치의치근이 조금 시계방향으로 비틀리는 양상으로 나타났으며, Krol의 유도면 형태에서는 지대치가 치근단 부위에서는 원설측으로 치경부에서는 근협측으로 변위되었다. 4. 유도면의 기울기가 $95^{\circ}$인 경우에서는 지대치의 치근은 치근단 부위에서 근설측으로 약간 변위되었고 치경부 방향으로 갈수록 반시계 방향으로 비틀리면서 보다 많이 변위되었으며, $100^{\circ}$인 경우에서는 지대치 치근단에서는 근협측으로 변위되었고 치경부방향으로 갈수록 시계방향으로 비틀리면서 보다 많이 변위되었다.

• 대한치과보철학회지
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• 제31권1호
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• pp.87-99
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• 1993

Many studies have been reported on the successful replacement of missing teeth with osseointegrated dental Implants. However, little research has been carried out on the bio-mechanical aspect of the stress on the surrounding bone of the free-standing type of dental implant prostheses. This experimental study was aimed to analyze the stress distribution pattern on the supporting tissues depending upon the position of osseointegrated implants supporting fixed bridges. In the cases of unilateral partially edentulous mandible (the 2nd premolar and the 1st and 2nd molars missing), two osseointegrated implants were placed at the 2nd premolar and 2nd molar sites (Model A) , the 1st and 2nd molar sites (Model B, Anterior cantilevered type), the 2nd premolar and 1st molar sites (Model C, Posterior cantilevered type). Chewing forces of dentate patients and denture wearer were applied vertically on the 2nd premolar, the 1st molar, and the 2nd molar of each model. A 3-Unit fixed partial denture was constructed at each model and cantilevered extension parts were involved in Model B and Model C. Two dimensional finite element analysis was undertaken. The commercial software (Super SAP) for IBM 16 bit personal computer was utilized. The results were as follows : 1. The magnitude of applied load influenced on the total value of stresses, but did not in-fluence on the pattern of stress distribution. 2. The magnitude of stress developed from the supporting tissues were in order of Model C,Model A,Model B. 3. High stresses were concentrated on the cervical and apical portion of the implant/bone interface. 4. A difference of the stress magnitude on the implant/bone interface between mesial and distal implant was most prominant in Model C and in order of Model A and Model B. 5. The stresses developed in Model A were evenly distributed throughout both implants. 6. The stresses concentrated on the cervical portion of cantilevered side were higher in the posterior cantilevered type than in the anterior cantilevered type.