Variation in accessory mental foramen frequency and number in extant hominoids

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.

Unique anomalous in the main mental foramen opening, mandibular canal pathway, and size and shape of genial tubercles: A case report

This clinical report presents a unique and previously unreported case of anatomical variations in the mandible, specifically involving the main mental foramen (MF), the mandibular canal (MC), and genial tubercles (GTs). The case involves a 21-year-old male seeking dental implant rehabilitation. The patient exhibited an unusual lingual exit path of the main left MF through the lingual cortical bone, with the MC following an anterior lingual direction along a lingual groove before exiting through the labial cortical bone between the apexes of the left canine and first premolar. Additionally, the patient displayed excessive enlargement and rare shape of the GTs. These rare anatomical findings presented challenges in dental implant planning. This case report emphasizes the importance of advanced imaging techniques like cone-beam computed tomography (CBCT) in evaluating mandibular structures for precise treatment planning and highlights the significance of understanding anatomical variations to prevent complications in dental procedures.

The inferior alveolar nerve and its relationship to the mandibular canal

Previous work on the mandibular canal, mental foramen, and mandibular foramen has focused on humans and some other non-primate mammals (with small sample sizes), but little work has investigated the mandibular canal and inferior alveolar nerve (IAN) across primates. However, it is important to understand the relationship between the IAN and mandibular canal due to the IAN's close relationship to the teeth and mastication, and thus dietary adaptations. While it is assumed that most bony canals within the skull grow around and form to pre-existing nervous structures, this relationship has never been validated for the IAN and mandibular canal. MicroCT scans of 273 individuals (131 females, 134 males, and 8 unknown sex) from 68 primate species and three mammalian outgroups, and diceCT scans of 66 individuals (35 females, 23 males, and 8 unknown sex) from 33 primate species and the same mammalian outgroups were used to create 3D models of the IAN and mandibular canal from which cross-sectional areas were taken at various points on the structures. Using qualitative descriptions, phylogenetic generalized least squares analysis, and phylogenetic ANOVAs, we were able to establish three main conclusions: (1) the mandibular canal is most often not a defined canal within the mandible of primates, (2) when the canal can be identified, the IAN does not comprise most of the space within, and (3) there are significant relationships between the IAN and the corresponding canals, with most showing isometry and the mental foramen/nerve showing negative allometry.

Anatomy of the accessory mental foramen in a Saudi subpopulation: A multicenter CBCT study

Aim

The aim of this is to evaluate the prevalence and location of the accessory mental foramen (AMF) in a Saudi population using cone-beam computed tomography (CBCT).

Methodology

CBCT data were retrieved from two dental facilities at two universities located in two different cities and filtered over a period of four years. The scans were aligned when the AMF was noticed, and then the size of both the AMF and mental foramen (MF), its location, and the distance from the AMF to the MF were recorded. The AMF measurements were compared between males and females and between the two sides of the mandible.

Results

In total, 603 CBCT scans were investigated. The percentage of scans with an AMF was 9.95% (n = 60), and AMFs were almost equally distributed on both sides. Only four cases (0.66%) of a second AMF were detected among the scans. The MFs on both sides were significantly larger in males than in females (P > 0.05), but they showed no differences in the sizes of the AMFs. The AMFs were most commonly located inferior and posterior to the MF. The distance between the MF and AMF ranged from 2.32 to 5 mm.

Conclusions

The prevalence of the AMF in this Saudi population was 9.95%, and it was significantly more prevalent in males than in females. Its proximity to the MF makes it clinically important to conduct proper detailed planning prior to performing any procedure that might risk the vital structures.