External and Internal Anatomy of Mandibular Permanent Incisors

A clear understanding of dental root anatomy, external and internal, is an essential prerequisite to all dental procedures. In periodontology, the external root morphology has been proven to have a clinical significance in the predisposing factors of periodontal diseases. Orthodontic literature shows the importance of radicular anatomy in orthodontic mechanics through the concept of anchorage. The significance of internal root anatomy has been emphasized by studies demonstrating that variations in canal geometry before cleaning, shaping, and obturation procedures had a greater effect on the outcome than the techniques themselves. The mandibular central incisor is the smallest tooth in the mouth, but the buccolingual dimension of its root is very large. This tooth is usually single-rooted; however, the root canal system of this group is unpredictable. The incidence of two canals has been reported as low as 0.3% and as high as 45.3%. The wide range of variation reported in literature regarding the prevalence of a second canal has been related to methodological and racial differences. This chapter will summarize the morphological aspects of the root canal anatomy published in the literature of the anterior mandibular teeth. This will provide precious knowledge regarding root canal morphology and its variation among populations.