Photoelastic Evaluation and Comparison Of Stress Transmission Characteristics of Three Different Overdenture Attachments Under Dynamic Loading Conditions – An In Vitro Study

Abstract

Statement of problem:

When two or more abutment teeth are used to support an over denture prosthesis, optimal stress distribution is required to minimize forces on abutments and residual ridge.

Purpose:

In this study photoelastic stress analysis was used to compare the stress patterns around canine abutments using three different overdenture attachments.

Material and methods :

Two teeth ie canines were used as abutments and were embedded in the photoelastic model. Overdentures were fabricated using Ball-Socket, Tissue bar and short coping attachments. The layer of light bodied silicone rubber base impression material was used to simulate oral mucosa and load of 5 to 50 lb was applied. Stress fringes that generated were photographed and evaluated quantitatively.

Results:

 The highest amount of stress was generated by Ball-Socket and short coping transmitted least amount of stresses. There was gross difference in magnitude of stresses between two types of retainers.

Conclusion:

There was more stress concentration around the abutments as the retentivity of the attachment increased.