Histologic evaluation of osseointegrated implants restored in nonaxial functional occlusion with preangled abutments

Of concern with the use of preangled abutments on implants is the transmission of masticatory forces and the angle at which they occur. Nineteen endosseous implants were placed in two subhuman primates. After 6 months, to allow for osseointegration, the implants were fitted with preangled abutments of various degrees and restored with type IV alloy castings. Straight abutments were used as control. Histologic evaluation revealed that, after 1 year of service, the implants exhibited complete osseointegration. Implants, whether restored with straight or preangled abutments, had no adverse effect on the surrounding bone. Soft tissue pockets measured, on average, from 2.2 to 2.6 mm; acute and chronic inflammatory cells were present. When crown loss was observed, it was caused by mechanical failure of components, such as gold screws and the screws used to secure the preangled abutments to the implants. Preangled abutments appear to be a valuable adjunct in implant dentistry, although long-term studies are needed for confirmation.