Unilateral Absence of Mental Foramen with Surgical Exploration in a Living Human Subject

A Comprehensive Analysis of the Radiographic Characteristics and Bilateral Symmetry of the Mental Foramen

OBJECTIVES

There is currently a scarcity of data on the frequency and bilateral symmetry of the position and other characteristics of the mental foramen (MF) and accessory mental foramina in Yemen. The objective of this study was to analyze the position and other characteristics, as well as the symmetry of the MF, in a sample of the Yemeni population.

MATERIALS AND METHODS

A retrospective analysis was conducted on a sample of 500 digital panoramic radiographs (1000 sides). The study examined various characteristics of the MF, including horizontal and vertical positions, shapes, appearances, and the presence of accessory mental foramina. Additionally, the study explored potential associations between these characteristics and variables such as the subject's gender, sides, and symmetry. Data analysis was performed using SPSS, and statistical significance was evaluated using chi-square tests; the p value was set at 0.05.

RESULTS

The horizontal position of the MF was most frequently observed between the first and second lower premolars (63.2%). The vertical position of the MF was predominantly below the apices of the lower premolars (66.2%). The majority of MFs had a round shape (46.3%). In 72% and 75.6% of cases, there was a continuous and descending relationship between the MF and the mandibular canal, respectively. Accessory mental foramina was present in 3.8% of cases. Gender differences were significant for the shape of the MF and the pattern of the canal on the right side. The symmetry rates for various features included horizontal positions (87.4%), vertical positions (82.6%), and shapes (80.4%).

CONCLUSION

The MF is most commonly situated horizontally between the lower premolars and vertically below the apices of these teeth. The majority of MFs showed a round shape and a continuous and descending relationship with the mandibular canal. In most instances, characteristics of the MF were symmetrical on both sides.

A rare case of an anatomical variant of nonexistent mental foramen

The mental foramen (MF) is an important anatomical landmark in the jaw, where the sensory nerve (mental nerve) and blood vessels emerge. To avoid sensory impairment or paresthesia caused by mental nerve damage, the MF must be accurately identified and localized. The literature describes a variety of anatomical variants of the MF, such as changes in its position, emergence profile or the presence of extra foramina. This case report documents a rare case of nonexistent mental foramina on the left side of the jaw, which was detected incidentally using cone-beam computed tomography (CBCT) prior to implant surgery planning.

Implications of impacted mandibular cuspids on mental foramen position

Objective

To determine the horizontal and vertical locations and dimensions of the mental foramen (MF) in digital panoramic images (DPI), and to evaluate the effect of impacted mandibular cuspids (IMC) on the position of the MF.

Materials and Methods

715 Digital panoramic images were obtained from the archives of oral radiology clinics of the College of Dentistry, Jouf University. Altogether 236 DPI that met inclusion and exclusion criteria were investigated. One specialist principal investigator examined and analyzed the DPI on a computer screen for horizontal location, average position, and vertical location of the MF.

Results

The most common horizontal location of MF with the apices of the teeth in the non-impacted group (NIG) was found to be c = 64.70%, and in the impacted group (IG) d = 47.10%. The average magnitude of MF relative to the apex of second bicuspid in the NIG was found to be 47.10% on the mesial side, and in IG 44.10% on the distal side. The average vertical distance of MF from the lower border of the mandible to the lower border of MF (DLM) in NIG was 14.13 mm (SD ± 1.75 mm), and in IG was 16.85 mm (SD ± 3.06 mm). The average vertical distance of MF from the alveolar crest to the superior border of MF (DAC) in NIG was 6.56 mm (SD ± 2.02 mm), and in IG was 6.67 mm (SD ± 2.28 mm).

Conclusion

The impacted mandibular cuspid has a definite influence on the location and position of the MF.