Relationship between location of main occluding area and occlusal support

Objectives:

The main occluding area on the dental arch is thought to be a region where the biting force is chiefly concentrated during mastication. However, there have been few studies examining the relationship between the location of main occluding area and the number of remaining occlusal supports. The purpose of this study was to investigate the changes of location of the main occluding area in related to reduction of occlusal supports.

Methods:

110 patients in a prosthodontic clinic at Matsumoto Dental University were recruited as subjects for this study. These subjects were classified depending upon the Eichner's index after the examination in both the location of remaining teeth and the presence of removable prostheses. The main occluding area was observed by using a temporary stopping. Each subject was instructed to clench a piece of temporary stopping and then the main occluding area was judged by observing the location of tooth on which the temporary stopping existed during clenching. Relationship between the location of main occluding area and the result of the Eichner's index was analyzed.

Results:

The main occluding areas were located on the first molars for almost all subjects of Eichner's A group. For the subjects of Eichner's B or C group, the more the absence of posterior occlusal supports increased, the more anteriorly the main occluding areas located (Kruskal Wallis test: p<0.05). Moreover, for the subjects with Eichner's B group, the main occluding areas in cases treated with removable prostheses tended to locate more posteriorly in comparison with those without removable prostheses.

Conclusion:

These findings suggested that the location of the main occluding area would be changeable in accordance with reduced occlusal supports.