Shortened dental arches and oral function.

To acquire more information concerning the changes of the oral functions in shortened dental arches, a cross-sectional clinical investigation was carried out among 118 subjects. They were classified into six classes, according to the degree and the symmetry of the shortened condition. The method was based on the measuring of variables which were derived from the oral function. The results showed two patterns of change in oral functions: oral functions that change slowly until four occlusal units are left and then change rapidly, and oral functions that change progressively without a sudden change. The preliminary conclusion is that there is sufficient adaptive capacity to maintain adequate oral function in shortened dental arches when at least four occlusal units are left, preferably in a symmetrical position.