This study was conducted to evaluate variations in and the prevalence of the lingual concavity. Images were taken between January 1, 2011, and August 31, 2015, from a total of 104 patient charts randomly selected from a private practice. These images were acquired from a single cone beam computerized tomography (CBCT) machine. The CBCTs were reviewed in cross-sectional images in both the left and right anterior incisor and posterior molar regions. These scans were classified into 1 of 3 categories-parallel, concave, or convex-based on the measurements of the level of concavity degree as well as the mandibular morphology observed. Lingual concavity characteristics including depth, angulation, and vertical location were also measured. Most of the posterior mandibular CBCT scans were classified as concave. Although there was no significant difference detected for race or gender, statistical significance was noted with regard to age, with an increase in prevalence observed at age 63 years and older. Of the 3 different morphological classifications used, the vast majority were identified as concave in the posterior mandibular regions and parallel in the anterior mandibular region. There was a significant decrease in concavity VL/height (bone loss) associated with age, which was most commonly seen in edentulous areas.