Morphology Research Of Mandibular Anterior Teeth

Most mandibular anterior teeth are one root with one root canal. Because of their position, people usually consider the root canal therapy of mandibular anterior teeth is easy. However, some research data show that mandibular incisors' root canal anatomy is comparatively complex, and root canal system has many variations. The two root canals, root canal diverge and root canal branch et al have considerable incidence. Besides, mesial-distal root canal walls of mandibular incisor teeth are thin. All of the above are the facors that can cause root canal therapy failure. In recent years, Walcer et al researched the partial Chinese mandibular incisors root canal morphology. However their focus was put on root canal grouping, root canal orifice quantity and the number of the root canal et al. There are few researches about root canal curvature and root canal cross-section morphology of mandibur anterior teeth. This research will investigate the mandibular anterior teeth on root canal curvature and root canal cross-section with radiologic method. It will be a reference to mandibular anterior teeth root canal therapy. This research includes two parts.Part oneRoentgenographic Investigation of Canal Curvatures in 487 Human Mandibular Anterior TeethObjects: To investigate root canal curvature in mandibular anterior teeth. Methods: 487 human mandibular anterior teeth were examined by indirect digital radiography both from buccolingual and mesiodistal directions. Analyse root canal curvature. Results: The major sort of mandibur anterior teeth is type I. 26.22% mandibular incisors and 31.45% mandibular canines curve in mesiodistal, 7.01% mandibular incisors and 18.87% mandibular canines curve in buccolingual. Mandibur curved incisors in type I have the largest degree of root canal curvature (mean=15.8° ), least radius of curvature(mean=4.7mm) and least length of the curved part of the root canal(mean=2.6mm).Conclusions: Root canal curvature in mandibular anteriors is complex, especially in mandibular incisors. In order to improving quality of root canal therapy, we need to understand types of root canal, degree of root canal curvature and radius of curvature completely.Part TwoRoentgenographic Investigation of Canal Cross-Section morphology in 476Human Mandibular Anterior TeethObjects: To investigate root canal cross-section morphology in mandibular anterior teeth. Methods: 476 human mandibular anterior teeth were examined by indirect digital radiography from both buccolingual and mesiodistal directions. Measure the root canal diameter in the cross-sections which was apart from the root apex 1, 2 and 5mm. Analysed root canal cross-section morphology. Results: In the mandibur incisors, the oval and flat root canals in the cross-sections which were apart root apex from 1, 2, and 5mm were 44.7% ^ 57.9% and 71.7% of the total root canal cross-sections. In the mandibur canines, the oval and flat root canals in the cross-sections which were apart root apex from 1, 2, and 5mm were 12.6%> 15.2% and 27.2% of the total root canal cross-sections. Conclusions: The mandibular incisors are usually oval and flat in the root canal cross-sections which are apart from the root apex in 5mm, and the mandibular canines are usually round in the root canal cross-sections. The buccal-lingual root canal cross-section diameter is larger than mesial-distal root canal cross-section diameter. The root canal cross-section diameter of mandibur anterior teeth decreases apically.