Influence of implant inclination and prosthetic abutment type on the biomechanics of implant-supported fixed partial dentures.

Abstract

Obtaining parallelism during implant placement often becomes difficult, leading to inclination of implants. The present study evaluated the stress distribution in 3-unit fixed partial dentures supported by two implants with different inclinations and prosthetic abutments. UCLAs or mini abutments were used considering 17º of implant angulation in different directions (mesial, distal, buccal, or lingual). To do so, three-dimensional finite element models were built and exported to a specific analysis software. Forces were applied to the functional cusps. Data was obtained in regard of maximum principal and von Mises stresses, in MPa. No relevant differences were observed in the stress values in the cortical and cancellous bone, and in the prosthesis with UCLA or mini abutments. However, a relevant stress reduction in the prosthetic screws of the tilted implant was observed when using UCLA abutments. According to the obtained results, it is possible to suggest that both, UCLA or mini abutments can be used for 3-unit fixed partial dentures when one of the implants is tilted. UCLA abutment might lead to less biomechanical problems related to screw loosening or fracture.