Stress effect of occlusal rest and implant support for removable partial dentures

 

 

Abstract

Objectives: This study investigated stress effect of occlusal rest and dental implant supporting a mandibular removable partial denture (RPD). 

Methods: Four theoretical test models of unilateral mandibular RPDs were constructed to represent the base for second premolar (P2), first molar (M1), and second molar (M2). The test models were designed to resist occlusal loading against the first premolar (P1) by means of mesial (Me) or distal (Di) rest, and implant located either at M1 or M2 site, as follows; Model 1: Me rest and implant at M1, Model 2: Me rest and implant at M2, Model 3: Di rest and implant at M1, Model 4: Di rest and implant at M2. The occlusal loading was concentrated at P2 (50N), M1 (100N), and M2 (100N) to calculate the stress resultants of forces and moments developed in the RPD.

Results: The vertical force driven against P1 was the greatest in Model 4, and was the lowest in Model 3. However, the force driven against implant support was the greatest in Model 3, and was the lowest in Model 4. The shear forces and bending moments developed in the RPD varied among the test models. The peak shear force was the greatest in Models 1 and 3, and bending moment was the greatest in Model 4. The force and moment were the lowest in Model 2. 

Conclusion: Within the limits of this study, the stress resultants of forces and moments developed in the RPD varied with different location of occlusal rest and implant support.  

 

Keywords: removable partial denture, occlusal rest, implant support, force, bending moment