(A) comparison of shear bond strength of various orthodontic adhesives

치의학과/석사[한글] 브라켓을 치아에 정확히 부착시키는 것은 성공적인 교정 치료의 기본이며 이를 위해서 교정용 접착제의 접착강도가 중요하고 또 교정치료가 장기간을 요하는 치료이기 때문에 그 접착강도가 시간과 온도변화에 의해 어느 정도의 변화를 보이는 지가 중요하다고 할 수 있다. 이에 본 연구에서는 임상가들이 사용하고 있는 교정용 접착제 중 Super C Ortho (혼합형 교정용 접착제), Mono-Lok**2 (비혼합형 교정용 접착제), Transbond(광중합 교정용 접착제)와 Fluorobond(불소를 함유한 치면열구 봉합제)를 선택하여, 구강내와 같은 환 경에서 시간과 온도변화에 따른 접착제의 접착강도의 변화를 알아보기 위해 실험군을 1군 (브라켓 부착 1시간 후), 27(브라켓 부착 24시간 후, thermocycling 10회 실시), 3군(브라켓 부착 24시간 후, thermncycling 1800회 실시)으로 분류하여 접착제의 전단 접착강도 를 측정 비교하고, 접착제외 종류에 따른 브라켓 탈락 양상을 관찰하여 다음과 같은 결과를 얻었다. 1. 1군에서는 Super C Ortho를 사용했던 경우와 Fluorobond를 도포한 후 Super Ortho를 사용했던 경우의 전단 접착강도가 높게 나타났으며, 2군에서도 Super C Ortho를 사용했을 때 접착강도가 가장 높게 나타났으나, 3군에서는 Mono-Lok**2 를 사용하였을 때 유의 성 있게 가장 높은 전단 접착 강도를 보여주었다(p<0.05). 2. 시간과 온도변화에 따라, Super C Ortho, Transbond를 사용했던 경우에는 2군에서 가장 높은 전단 접착강도를 보였고 3군에서 가장 낮은 전단 접착강도를 보였으나, Mono-Lok**2 를 사용했을 때는 3군에서도 2군에서와 같이 높은 전단 접착강도를 보였고, Fluoro bond를 도포한 후 Super C Ortho를 사용했던 경우에는 시간이 지남에 따라 전단 접착강도의 계속적인 감소를 나타냈다. 3. 브라켓 탈락 양상은 Mono-Lok**2 , Transbond, Fluorobond를 도포한 후 Super C Ortho를 사용했던 경우에는 주로 치아와 접착제 경계부에서 탈락이 일어났으나, Super C Ortho를 사용했던 경우에는 브라켓 기저부와 접착제의 경계부에서의 탈락과 치아와 접착제 경계부에서 탈락이 비슷한 정도로 일어났다. 이상의 결과로 볼 때 브라켓 부착시 접착제의 선택에 있어 시간과 온도 변화에 따른 접착제의 전단 접착강도의 차이를 고려하여야 할 것으로 사료된다. A Comparison of Shear Bond Strength of various Orthodontic Adhesives Mi- Hee You, D.0.S. Department of Dental Science, The Graduate School, Yonsei University (Directed by Assistant Professor Chung-Ju Hwang, D.D.S., Ph.D) Bending of brackets is one of the essential factors for successful orthodontic treatment, so bond strength of orthodontic adhesives are very important. The purposes of this research are to compare shear bond strength of various orthodontic adhesives and to evaluate failure sites. One-hundred twenty extracted human first premolars were prepared for bonding and premolar brackets were bonded to prepared enamel surfaces with Super C Ortho, Mono-Lok**2 , Transbond, and Super C Ortho after applying Fluorobond. Afer bonding of brackets, teeth specimens were divided into group 1, group 2, and group 3. In group 1, specimens were stored at humidor 37℃ in 1 hour and in hour 2, specimens were stored at humidor 37℃ in 24 hours, thermocycled 10 times and in group 3, specimens were stored at humidor 37℃ in 24 hours, thermocycled 1800 times. Then the Instron testing machine was used to test the shear bond strength of brackets to enamel. After debonding, brackets and enamel surfaces were examined under stereoscopic microscope to determine the failure sites The results were as follows : 1. In group 1 shear bond strength was significantly highest of using Super C Ortho after applying Fluorobond and Super C Ortho only and in group 2 also was highest of using Super C Ortho but in group 3 was highest of using Mono-Lok**2 . 2. According to time and temperature change, in using Super C Ortho the group 2 had significantly highest strength and group 3 had lowest strength, in using Mono-Lok**2 the group 2 and had higher strength than group 1 and in using Super C Ortho after applying Fluorobond shear bond strength decreased constantly. 3. In Super C Ortho after applying Fluorobond, Mono-Lok**2 and Transbond, the failure sites were tooth-resin interface and in Super C Ortho were at almost same ratio bracket base-resin interface and tooth-resin interface. [영문] Bending of brackets is one of the essential factors for successful orthodontic treatment, so bond strength of orthodontic adhesives are very important. The purposes of this research are to compare shear bond strength of various orthodontic adhesives and to evaluate failure sites. One-hundred twenty extracted human first premolars were prepared for bonding and premolar brackets were bonded to prepared enamel surfaces with Super C Ortho, Mono-Lok**2 , Transbond, and Super C Ortho after applying Fluorobond. Afer bonding of brackets, teeth specimens were divided into group 1, group 2, and group 3. In group 1, specimens were stored at humidor 37℃ in 1 hour and in hour 2, specimens were stored at humidor 37℃ in 24 hours, thermocycled 10 times and in group 3, specimens were stored at humidor 37℃ in 24 hours, thermocycled 1800 times. Then the Instron testing machine was used to test the shear bond strength of brackets to enamel. After debonding, brackets and enamel surfaces were examined under stereoscopic microscope to determine the failure sites The results were as follows : 1. In group 1 shear bond strength was significantly highest of using Super C Ortho after applying Fluorobond and Super C Ortho only and in group 2 also was highest of using Super C Ortho but in group 3 was highest of using Mono-Lok**2 . 2. According to time and temperature change, in using Super C Ortho the group 2 had significantly highest strength and group 3 had lowest strength, in using Mono-Lok**2 the group 2 and had higher strength than group 1 and in using Super C Ortho after applying Fluorobond shear bond strength decreased constantly. 3. In Super C Ortho after applying Fluorobond, Mono-Lok**2 and Transbond, the failure sites were tooth-resin interface and in Super C Ortho were at almost same ratio bracket base-resin interface and tooth-resin interface.restrictio