• 대한치과교정학회지
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• 제27권4호
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• pp.661-668
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• 1997

치열의 crowding을 해소하는 방법에는 크게 발치, 비발치로 크게 나눌 수 있다. 발치로 교정하는 경우 주로 고려되는 발치대상 치아는 제1, 2 소구치이며 그 다음이 제2 대구치, 하악전치, 제1대구치등 이다. 하악전치의 발치는 소구치 발치가 여의치 않을 때, 선택적으로 사용될 수 있다. case를 잘 선택한다면, 치료시간도 줄일 수 있고, 간편하게, 심미적 및 기능적으로도 좋은 효과를 얻을 수 있다. 아직 이에 대한 국내 연구와 보고가 활발하지 않아 소개하고자 한다.

• 대한치과보철학회지
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• 제32권4호
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• pp.484-514
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• 1994

Cantilever bridge is widely used by mny clinicians, but its worst mechanical character, so called Class I lever system, makes dentists hesitate to restore the missing tooth with it. Therefore it is important to study stress of the cantilever bridge. In this study, two models of cantilever bridges that restores the missing mandibular second molar with two abutment teeth were constructed. One model was a type of cantilever bridge supported by a normal alveolar bone, the other one was supported by an alveolar bone resorbed to its 1/3 of root length. Maximum bite force(550N) and funtional maximum bite force(300N) were vertically applied to the distal end of the pontic, distal 1/3, and distal half of the pontic. And each force was also applied to centric occlusal contacts as a distributed force. Total 16 loading cases were compared and analyzed with 3-dimensional finite element method. The results were as follows: 1. The stress was concentrated on the joint of the pontic and the retainer, grooves, and distal cervical margin of the posterior retainer. 2. In case of maximum bite force(550N) at the end of the pontic, the risk of fracture at the joint of the pontic and the retainer was high. 3. In case of distributed force in centric occlusion and functional maximum bite force(300N), the stresses were less than the yield strength of the type VI gold for any loading cases. 4. In case of alveolar bone resorption, the occlusal force to the cantilever pontic caused more stress on the root apex and less stress on the alveolar crest region of the distal surface of the posterior abutment. 5. In case of alveolar bone resorption, the displacement was larger than that of normal alveolar bone in all loading cases.