The korean journal of orthodontics (대한치과교정학회지)

The Korean Association Of Orthodontists (대한치과교정학회)
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STUDY ON THE ERUPTION OF THE LOWER THIRD MOLAR IN THE CASES OF NON-EXTRACTION AND THE EXTRACTION OF FIRST PREMOLAR

제 1 소구치 발치 증례와 비발치 증례에서의 하악 제 3 대구치 맹출에 관한 연구

  • Chung, Kyu-Rhim (Department of Orthodontics, College of Dentistry, Kyung Hee University) ;
  • Lee, Jeong-Min (Department of Orthodontics, College of Dentistry, Kyung Hee University)
  • 정규림 (경희대학교 치과대학 교정학교실) ;
  • 이정민 (경희대학교 치과대학 교정학교실)
  • Published : 1993.03.01
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Abstract

This study was designed to recognize the factors which can affect the normal eruption of the lower third molar and the eruption rate of the lower third molar in the cases of non-extraction and the extraction of first premolar. The sample consisted of 214 cases of extraction of first premolar and 119 cases of non-extraction, and all of these cases were divided into erupted and impacted lower third molar groups and were analized according to the pantomogram. The results of the study were as follows : 1. The eruption rate of the touter third molar was $54.67\%$ in the group of extraction of the first premolar and $35.29\%$ in the non-extraction group. 2. The early inclination of the erupting lower third molar has significant effect in the eruption of it. 3. In the orthodontic treatment, the extraction of first premolar is one of the factors infuencing the nomal eruption of lower third molar. 4. The available space for the normal enruption of lower third molar was greater in first premolar extraction case than in non-extraction case.

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