A Cone-Beam Computed Tomography Study of the Morphological and Morphometric Variations in the Mandibular Lingula and Its Clinical Implications.

Background/

Objectives

The mandibular lingula (ML) is a small bony projection on the medial surface of the ramus and serves as the first reference point identified during sagittal split ramus osteotomy (SSRO) or inferior alveolar nerve block (IANB). Anatomical variations in the mandibular ramus have been shown to exist across different populations. Understanding these population-specific differences enhances both clinical safety and diagnostic precision. However, there is a paucity of anthropological data amongst the Mongoloid population, especially in Southeast Asia. Hence, this study aimed to investigate the (i) distance of the lingula to different mandibular anatomical landmarks and its localization, (ii) lingula shape, and (iii) differences between gender and the sides of the mandible amongst the local ethnic groups.

Methods

This retrospective cross-sectional study consisted of 206 cone-beam computed tomography (CBCT) images of 77 males and 129 females (mean age 33), with a total of 412 hemimandibles. Measurements were performed on three-dimensionally reconstructed CBCT images.

Results

The most common shape was the truncated type. The distance of the lingula to the anterior (LiA), posterior (LiP), superior (LiS), and inferior (LiI) borders of mandible were 17.84 (2.25) mm, 14.46 (3.44) mm, 17.73 (3.00) mm, and 27.05 (4.40) mm, respectively. No significant difference exists between the sides of the mandible. Sexual dimorphism existed for all lingula measurements except LiA. Indians have smaller rami with more anteriorly and inferiorly placed ML than Malay and Chinese. The majority of ML was located 8.55 mm above the occlusal plane.

Conclusions

This study provides information on the ML and its surrounding ramus structure in the local population. Such variations must be accounted for in SSRO and IANB.