Investigation of complete dental arches of 23 patients aged at least 75 years.

Numerous factors help to conserve the dentition of elderly patients, such as healthy food habits, a strong physical constitution, and a good quality of life. The aim of this study was to define a model that takes into account the integration of both the structural and functional aspects of a healthy dentition. Twenty-three patients aged at least 75 years were recruited. The patients were required to possess all of their dentition and have no prosthetic rehabilitations and be asymptomatic for temporomandibular joint disorders. Occlusal characteristics were measured and recorded using the criteria adopted by the US National Health and Nutrition Examination Survey: presence or absence of rotation of the upper arches, trend of the occlusal table, and distribution of occlusal contacts during movements. We believe that the following parameters are predictive of a condition of the dental arches' equilibrium: crowding and disalignment of the teeth, derotated position of the upper arches, absence of the curve of Spee, an occlusal plane trend contrary to spherical theory, and presence of group function on the working side and malocclusion on the nonworking side. We consider that these factors are merely the consequence of correct functioning within the framework of favorable environmental factors.