(PR70) Use of CBCT to Determine the Morphological Differences of Mandibular Incisors in a Military Population: A Modified Classification System

Successful endodontic treatment is a multi-factorial process reliant on proper diagnosis, knowledge of morphology, access design, cleaning, shaping, and adequate obturation. The aim of this study was to evaluate mandibular incisors using CBCT images to 1) assess morphology (canal width, shape, and Vertucci classification), 2) identify ideal access location, and 3) present a modified Vertucci classification system to help guide initial access location.

Methods: A total of 200 mandibular lateral incisors and 200 mandibular central incisors were evaluated from CBCT (3D Accuitomo 170) scans of 100 patients using 3D imaging software. Canal width measurements were determined based on the average of three measurements from an axial slice. Straight line access was determined from a sagittal slice.

Results: The mean canal width at its widest point in teeth #s 23, 24, 25, and 26 was 2.31 mm, 1.84 mm, 1.82, and 2.28 mm, respectively. Significant differences between tooth types (central and lateral) with respect to widest width (P < 0.001) and CEJ width (P = 0.01) were found. Canal shape incidence rates were circular 17.9%, oval 31.8%, and long oval 50.3%. Straight line access locations were facial: 28.5%, incisal: 69.9%, and lingual: 1.6%. Primary Vertucci class included type 1: 48.7% and type 3: 45.4%.

Conclusions: An incisal or facial approach is recommended when accessing mandibular incisors due to their oval shape and high probability of possessing two canals. Adding a straight line access designator to Vertucci’s classification system for mandibular incisors may help facilitate adequate cleaning and shaping of canals.