Evaluation of stress patterns in bone around dental implant for different abutment angulations under axial and...

The replacement of missing anterior teeth presents peculiar challenges to the Prosthodontist. Implants are increasingly gaining favour for the same. The morphology of existing bone in the premaxilla often dictates that implants are placed at angles that are difficult to restore with conventional abutments. However, the angulated abutments might transfer unfavourable forces to the implant or bone, thereby compromising the prognosis of the treatment. Because, it is difficult to assess the generated forces clinically, a finite element analysis was chosen for the present study as it is useful tool in estimating stress distribution in the contact area of the implant with the bone.

In this study, the frontal region of the maxilla was modelled with a cortical layer 1.5 mm thick containing an inner cancellous core. The implant was cylindrical, round ended, with length 13 mm and diameter 4.1 mm. The abutment was modelled as 7 mm in height with a 5 degree occlusal taper. The different abutment angulations used were 0°, 10°, 15° and 20°. The amount of loads used were 100, 125, 150, 175 and 200 N axially, and 50 N in oblique direction, to approximate the kind of loads seen in clinical situations.

It was seen that, as the abutment angulation changes from 0° to 20° both the compressive as well as tensile stresses increased; but, it is within the tolerance limit of the bone.

It seems reasonably safe to use angled abutments in anterior implant supported prostheses, in the maxillary arch.