Morphologic observation on root canal of mandibular incisors / 实用口腔医学杂志

medial distal wall. The root canal length of central and lateral incisors were (12.96?6.46) mm and (11.47?6.32) mm respectively. The double root canal was found in 35.9 % of central incisors and in 27.5% of lateral incisors. Most mandibular incisors with long concavity had single root canal. Conclusion: The root canal wall of mandibular incisors was thinner in medial and distal wall than in lingual and labial wall. Mandibular incisors have higher rate in double root canal and the long concavity is not significantly related with number of root canal.

In vitro study of the anatomy of 80 maxillary first permanent molars / 实用口腔医学杂志

Objective:To study the anatomy of the maxillary first permanent molars. Methods:Macrography was used to observe the morphology of the mesiobuccal root,the degree of abrasion,the morphology of the floor of pulp cavity, the number and type of apical foramen.Vernier was used to measure the length indexes and the distance from the apical foramen to the tip of the root.Clearing technique was used to investigate the root canal systems. Results:26.9% of mesiobuccal root had type III apical foramen,56.25% of mesiobuccal root had two canals,7.5% teeth had three root canals. Conclusions: The maxillary first permanent molar has a high ratio of more than one root canal in mesiobuccal root(63.75%).