Anatomy of primary incisor and molar root canals.

Knowledge of the size, morphology, and variation of the root canals of a primary tooth is useful in visualizing the pulp cavity during treatment. The roots of the primary teeth are formed completely approximately 16 to 20 months following eruption.1 In approximately three years the roots begin to resorb at the apex or on a lateral surface near the apex.2 The form and shape of the root canals roughly correspond to the form and shape of the external anatomy of the teeth. However, as root resorption of primary teeth begins, dentin is deposited within the root canal system and may change the number, size, and/or shape of the root canals significantly. 3 The presence of necrotic pulp or the unsuccessful outcome of pulpotomy procedures may make endodontic therapy of the root canal systems desirable if extraction of the tooth is to be avoided. The purpose of this study was to determine the length of the root canals of primary maxillary incisors and mandibular molars, and to examine the root canal anatomy visually using a clearing technique.