A STUDY ON THE ROOT CANAL MORPHOLOGY OF HUMAN MAXILLARY FIRST PREMOLAR WITH TRANSPARENT SPECIMENS

투명표본(透明標本)에 의한 상악(上顎) 제일소구치(第一小臼齒)의 근관형태(根管形笞)에 관(關)한 연구(硏究)

Eighty four human maxillary first premolars were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root canals, the frequency and location of lateral canals, the frequency and location of transverse anastomoses, the curvature of root canals, the location of apical foramens, and the frequency of apical deltas. The results were as follows: 1. Most of the teeth demonstrated two canals, but 20.2% of the teeth were found to have one canal. 2. Of the 151 canals studied, 38.4% of the canals were found to have lateral canals and these ramifications were usually located in the apical third of the root. 3. Of the two root canals in one root, 35.7% of the canals were found to have transverse anastomoses and were usually located in the middle third of the root. 4. 15.2% of apical foramens were located directly on the root apex and 84.8% of them laterally, and 52.3% of canals showed distal curvature.