The Influence of Number and Distribution of Occlusal Cantilever Contacts on Closing and Chewing Forces in Dentitions with Implant-Supported Fixed Prostheses Occluding with Complete Dentures

Axially directed closing and chewing forces were measured in patients with mandibular fixture-supported cross-arch bilateral posterior two unit cantilever fixed prostheses occluding with maxillary complete dentures. Eight miniature strain-gauge transducers mounted in the maxillary denture enabled registration of local and total forces over the entire prosthetic restoration simultaneously. In asic occlusion, with simultaneous occlusal contacts on all occluding units, closing and chewing forces were distally increasing. Infraoccluding the first cantilever unit bilaterally approximately 100 µm resulted in decreased total closing and chewing forces over the cantilever segments, but did not influence the leverage at the cantilever joint distal to the distal retainers. Infraoccluding the second cantilever units approximately 100 µm caused a pronounced reduction of both the total closing and chewing forces over the entire prosthetic restoration as well as over the cantilever segments, and also resulted in a marked (50%) decrease in the leverage at the cantilever joints. Causes of the force and leverage reductions and some clinical considerations are discussed. Keywords: complete dentures, implant-supported prostheses, occlusal forces