Angled implant abutments: a practical application of available knowledge.

BACKGROUND

When dental implants are not placed parallel to adjacent teeth or contiguous implants, the clinician can use angled abutments to achieve proper restorative contours. However, increased stresses on implants and bone have been associated with use of angled abutments. In this regard, there are unresolved issues concerning implant survival and potential prosthetic complications that can arise when angled abutments are used to align prosthetic positions.

TYPES OF STUDIES REVIEWED

The authors searched the dental literature for clinical trials that appraised the survival rate and complications (biological and technical) associated with pros-theses that are supported by angled abutments.

RESULTS

The results of photoelastic stress assessments, finite element analysis and strain-gauge studies indicated that increased abutment angulations result in the placement of a greater amount of stress on prostheses and the surrounding bone than that associated with straight abutments. However, survival studies did not demonstrate a significant decrease of prostheses' longevity associated with angled abutments. Furthermore, there was no additional bone loss adjacent to implants that supported angled abutments compared with straight abutments, and angled abutments did not manifest an increased incidence of screw loosening.

CLINICAL IMPLICATIONS

The use of angled abutments facilitates paralleling nonaligned implants, thereby making prosthesis fabrication easier. These abutments also can aid the clinician in avoiding anatomical structures when placing the implants. In addition, use of angled abutments can reduce treatment time, fees and the need to perform guided bone regeneration procedures.