Anatomical relationship of the incisive canal to structures of the anterior mandible using cone beam computed tomography

Abstract

Objectives: Endodontic and implant surgery in the anterior mandible carries the risk of potential complications. Knowledge of the location and position of the root in the mandible, the morphology of the root and mandible, and proximity to adjacent anatomic structures are important in prevention of complications. The aims of this study were to 1) determine the prevalence and course of the incisive canal with respect to the anterior root apices and mandible, 2) acquire normative information regarding the location of the anterior roots in relation to the mandible, 3) evaluate the anterior mandibular height and width and 4) determine whether gender or age correlated with any of the measurements. Methods: Cone-beam computed tomography scans of 106 patients were evaluated in a cross-sectional plane for the presence of the mandibular incisive canal (IC) at the radiographic apex of the six mandibular anterior teeth. When the IC was present, ten anatomic measurements were made. Four measurements were made when the IC could not be identified. Generalized estimating equations were used to compare measurements with pairwise comparisons being made if p≤0.05. P values were adjusted for multiple comparisons with the Tukey method. Pearson correlation coefficients were calculated to compare the change in measurements with gender and age. Results: An IC was identified in 80.6% of the images and 98% of patients had the IC identifiable in least one image. The presence of the incisive canal significantly decreased from the area of the canines to the central incisors. The amount of buccal bone overlying the root decreased as the tooth was located more anteriorly in the arch. The mean buccal bone over the IC increased from the area of the canines to the central incisors. There was no significant difference in the IC diameter in relation to its location. The distance from the tooth apex to the IC increased with a more anterior tooth location. The mean horizontal distance from the tooth apex to the IC was to the lingual for all tooth types. The mean mandibular width at a level 3mm coronal to the apex decreased toward the midline, whereas the mean mandibular width at the level of the IC increased toward the midline. The mandibular height and the distance from the alveolar crest to the incisive canal had no significant differences at any point measured. The only significant difference with regard to sex and age was the height of the mandible with the distance being smaller at all locations in females. Conclusions: Collectively, the data from this study indicates anatomic relationships should be considered in pre-surgical planning to avoid neurosensory disturbances and other complications. With increased interest in performing a thorough examination in the interforaminal region prior to surgery, cross-sectional images should be utilized to obtain case specific information with regard to anatomic structures of the anterior mandib.