부산대학교 도서관

In this report, transverse serial sections were employed to investigate the shape of the root canals of mandibular deciduous central incisors.Twenty-one mandibular deciduous central incisors were decalcified in nitric acid and embedded in celloidin. Transverse serial sections were made, stained with hematoxylin and eosin and studied microscopically.Root canal forms were classfied into three types: simple, isthmus and compound-round. The root canal itself was divided into thirds: coronal, middle and apical.The following results were obtained;1. Though the isthmus type was frequent in the middle and apical portions, in all portions the root canal was generally of the simple type.2. Lateral branches occurred in two(9.5%) of twenty-one teeth, the all of which were in the apical portion.3. No apical ramification occurred.4. No adherent denticles were observed in twenty-one teeth. Of the twenty-one teeth observed, five were vital. Free denticles were observed in three of those five.5. In the cross-cut sections of the middle of the established portions, we measured the labio-lingual and mesio-distal diameters of the root canals and the minimum distance from the root canal to the cement surface. The labio-lingual diameter averaged 1.14 mm in the coronal third,0.84 mm in the middle third and 0.47 mm in the apical third. The mesio-distal diameter averaged 0.79 mm in the coronal third,0.51 mm in the middle third and 0.31 mm in the apical third. In all portions, the shortest distance between root canal and cement surface averaged less than 1 mm.