Occlusal force pattern during mastication in dentitions with mandibular fixed partial dentures supported on osseointegrated implants

The occlusal force pattern during chewing and biting was studied in eight edentulous patients whose dentitions had been restored with mandibular bilateral posterior two-unit cantilever fixed prostheses supported on osseointegrated titanium fixtures and occluding with complete maxillary dentures. The chewing pattern was comparable to that reported for subjects with complete healthy dentitions or with tooth-supported cross-arch fixed partial dentures. However, during chewing and swallowing the voluntary capacity of the jaw-closing muscles was used to a much greater extent. Contrary to reports for cantilevers in tooth-supported cross-arch unilateral posterior two-unit cantilever fixed partial dentures occluding with natural teeth, the posterior cantilever segments in the present fixture-supported cantilever prostheses occluding with complete dentures regularly exhibited the largest local forces. Despite this, material failures of this type of fixed prostheses are rare, as demonstrated in long-term follow-up studies.