회전된 구치를 개선시키기 위해 사용하는 precision-TPA(transpalatal arch)를 삽입방법들 -근심삽입법, 원심삽입법, 확장력을 부여한 근심삽입법(이하 근심확장법)-에 따라 동적인 치 아이동의 양상과 치열궁의 변화를 비교하기 위해 본 교실에서 개발, 제작한 Calorific machine을 이용하여 실험한 후 회전된 치아와 고정치간의 이동양상을 계측하여 통계처리한 결과 다음과 같은 결론을 얻었다. 1. 구치간 폭경은 근심삽입법에 의해 감소하였고, 원심삽입법과 근심확장법에 의해서 증가하 였다. 2. 원심삽입법에 의해서 치열궁 장경이 가장 증가하였고, 근심확장법, 근심삽입법 순으로 증 가하였다. 3. 근심삽입법의 회전중심은 근심소와(mesial pit)와 중심소와(central pit)사이에 위치하였고, 원심삽입법에서는 원심소와(distal pit)와 원심설측교두(distolingual cusp)사이에, 근심확장법 은 원심소와(distal pit)에 위치하였다.
Dr. Youn-Sic Chun and coworkers invented the new machine for getting information about the relative effectiveness of the orthodontic appliances and we named it Calorific machine. The author and colleagues used this machine to compare with tooth moving mechanism by 3 types of the insertion method of precision-TPA for derotating the posterior teeth. We measured the distance of tooth movement and found out the rotational center on the occlusal X-ray film and the tooth movement on the occlusogram and then processed paired t-test by SAS program. The results were as follow : 1. In the intermolar width, the mesial insertion method showed the loss of distance, and the other methods(-distal insertion method, mesial expansion method-) showed the increase of distance. 2. In the arch length, the distal insertion method was exhibited as most recommandable way for increasing the arch length. 3. The rotation center of the mesial insertion method for derotating the molar, was located between mesial pit and central pit of the lower 2nd molar. and, in the distal insertion method, it was located between distal pit and distolingual cusp, and in the mesial expansion method was located at distal pit.
