A three-dimensional computerized tomography study into the morphological interrelationship between anterior and posterior guidance and the occlusal scheme in human Caucasian skulls

Background The articular eminence of the glenoid fossa together with the occlusal guiding surfaces represent two fundamental determinants of mandibular movement and even though subject to numerous investigations the relationship between both structures still remains unclear today. The purpose of this 3D investigation was to characterize the inclinations of the articular eminence, measure the inclinations of maxillary occlusal guiding surfaces, investigate the occlusal scheme present and examine the relationship between anterior and posterior guidance. Methods Several three-dimensional measurements obtained through computerized analysis of virtual models of 163 human skulls reconstructed from cone-beam computed tomography (CBCT) images were analyzed and correlated. Results The inclinations of the articular eminence and of the occlusal guiding surfaces revealed large individual variation. Second molars showed the lowest inclination values with a significant number of first and second molars presenting buccally inclined guiding elements. Anterior guidance showed slightly higher inclination values than posterior guidance. Significant correlations were found between the inclination of the articular eminence and the posterior passive centric line of occlusion. Conclusions The occlusal scheme of sequential guidance with front canine dominance was confirmed. Inferring a direct etiologic anatomical interrelationship between anterior and posterior guidance may be an oversimplification of the craniomandibular system.