Dimension and Location of the Mandibular Lingula: Comparisons of Gender and Skeletal Patterns Using Cone-Beam Computed Tomography

Abstract

Objective. The study aimed to investigate and measure the anatomical relationship between the mandibular lingula (Li) and skeletal patterns using cone-beam computed tomography (CBCT). Materials and Methods. In total, 72 participants (23 men and 49 women) were categorized into three groups according to their skeletal patterns (specifically, the A point–nasion–B point (ANB]) angle) as follows: Class I (0° < ANB < 4°), Class II (ANB ≥ 4°), and Class III (ANB ≤ 0°). The CBCT images of 144 rami were collected, and the distance from the Li to the external oblique ridge (Li-EOR), internal oblique ridge (Li-IOR), posterior border of the ramus (Li-PBR), inferior border of the ramus (Li-IBR), sigmoid notch (Li-Sm), and mandibular foramen (Li-MF) was examined. The Li-hMF (horizontal distance from the Li to the MF) and Li-vMF (vertical distance from the Li to the MF) were measured. The comparisons of gender, side (right and left), and skeletal patterns were then evaluated by statistical analysis. Results. The values of the Li-EOR and Li-PBR (19.99 mm and 15.93 mm, respectively) were significantly higher in men than in women (18.85 mm and 14.89 mm, respectively). Moreover, the Li-IBR was higher in men (32.91 mm) than in women (30.40 mm). Both sides (right and left) and skeletal patterns demonstrated that the Li-EOR, Li-IOR, and Li-PBR were not significantly different. Pearson’s correlation test reported a strong correlation between the Li-EOR and Li-IOR (r=0.610). Conclusion. The distances from mandibula lingula to the external oblique ridge, posterior border of ramus, and inferior border of ramus were significantly longer in men than in women. Similarly, both horizontal and vertical distances from the lingula to the mandibular foramen were significantly longer in men than in women. Therefore, the results demonstrated that the Li was longer and more protruding in men than in women. With respect to the horizontal distance from the mandibular lingula to the mandibular foramen, of the three types of the skeletal system (Class I, Class II, and Class III), Class III was the significantly largest.