The Effect of Abutment Angulation on Stress Transfer for an Implant

Abstract

This investigation compared the stress production characteristics of five abutment angulations for a specific implant system. Photoelastic resin was cast directly to a 3.75 x 10-mm Branemark fixture (Nobelpharma USA, Inc, Chicago, IL) in a 50 x 70 x 13-mm mold. A strain gauge rosette was also incorporated in the resin to allow precise determination of normal stresses at a specific point. Each 4-mm abutment (15 degrees, 25 degrees, and 35 degrees from Implant Innovations (West Palm Beach, FL) and 0 degree and 30 degrees from Nobelpharma) was assembled on the fixture, subjected to 178N load, and viewed with a circular polariscope. Observed fringes were photographed and strain indicator readings were recorded. Mean observed fringe order and mean principle stress and strain at the location of the rosette were determined. At the location of the rosette, all five of the abutments produced principal strains (compressive and tensile) within the physiological zone for bone. The rosette was located approximately 4 mm away from the fixture. Higher stresses and strains can be expected in regions closer to the implant.