Validity of a Dental Reference to Locate the Mental Foramen

Objectives: In the Litterature, dental organs have often been used to situate the mental foramen. However, teeth form a part of an alveolar bone, subject to many adjustments, whereas mental foramen forms a part of a tissue more genetically determined. Moreover, they have different embryologic origins. The aim of the study was to evaluate the validity of the teeth as landmarks to locate this foramen. Methods: The material consisted of 62 dry mandibles from a Nubian’s homogeneous population (1890 to 1580 BC). This sample has been choosen for the excellent preservation of mandibles and teeth. A digital caliper has been used to register the metric variables. Position of the mental foramen was codified and determined by the perpandicular to the alveolar plane of premolars and molars, going through the centre of this foramen. That situation has been indexed in comparison with a tooth or a septum of a same side. Correlations has been established between these locations and different metric variables: gonial angles (G), lenghts (MRL) and widths (MRWR on the right, MRWL on the left) of the mandibular ramus, lenghts of the mandible (ML), and the distances mental foramen-basilar margin (FBR on the right, FBL on the left). Results: On one hand, many statistically significative correlations existed between the mandibular variables (with Pearson’s correlation coefficients), as for example: ML and MRWR (p=0,0002), ML and MRWL (p=0,00001), ML and MRL (p=0,000002), MRL and FBL (p=0,00007), MRL and FBR (p=0,0009)…, rendering a logic in the tridimensional architecture of the mandibular bone; on the other hand, no statistically significant correlation has been found between positions of the mental foramen codified and: G, MRL, MRWR, MRWL, ML, FBR, FBL (p>0,05 with Spearman’s correlation coefficients). Conclusions: The dental reference shouldn’t be an appropriate landmark to locate the mental foramen, because of independent evolutions.