Gender variation of the position of the mandibular aperture in three-dimensional space located using spiral tomography

Introduction. The evaluation of mandibular opening topography has a very important cognitive and utilitarian meaning in dentistry. In many clinical situations, it is necessary to take into account gender and individual variability, bilateral differences in the position of the mandibular aperture on the mandibular branch. Each of these factors can have a huge impact on the effectiveness of anaesthesia in this area. Aim of the study. To determine the variability of the position of the mandibular opening in three-dimensional space with respect to the three axes of rotation of the mandibular branch. Evaluation of the position of the mandibular aperture with reference to selected anthropometric points on the mandibular branch with regard to asymmetry and dimorphic differences was undertaken. Material and methods. Images of fifty patients (26 women, 24 men) were analysed in a homogenous group (aged 30-35 years) of both sexes. The median plane was virtually created and, in relation to it, both anthropometric points and angles of the mandibular branch were measured bilaterally in three axes. A total of twenty-eight measurements were taken for each patient. On the basis of anthropometric measurements, the facial index was determined. By means of stepwise regression, the features that most determined the gender variation of the parameters examined were determined. Results. In the patients from the Garson broad-band group, the most significant covariation between the position of the mandibular apex in relation to the posterior margin of the mandible and the angle of the mandible was demonstrated. In these patients, the mandibular apex is located more distally to the posterior margin of the mandible than the average 15.77 mm in men and 14.10 mm in women. There were marked differences in gender – the majority of measured values were higher in men than in women. Conclusions. In the range of the variability of the position of the mandibular aperture in the threedimensional space, which has been referred to the vertical, transverse and anterolateral axis, there is a significant individual variability. Significant bilateral and dimorphic differences were observed. This affects the location of the mandibular opening. The obtained results suggest, especially in patients with high values of the angle of the mandible and in patients with a significant craniofacial width, that the distance of the mandibular opening from the posterior margin of the mandible branch decreases.