Three-dimensional finite element analysis of stress distribution of two-retainer and single-retainer all-ceramic resin-bonded fixed partial dentures.

OBJECTIVE

A long-term clinical study previously stated that adhesively luted resin-bonded fixed partial dentures (RBFPDs) with two retainers exhibited two complications (loss of adhesion or fracture between retainer and pontic) when compared to RBFPDs with a single retainer. The reasons for these complications were not reported. The aim of this study was to evaluate the stress distribution of two-retainer and singleretainer zirconium dioxide RBFPDs by using three-dimensional finite element analysis (3D FEA).

METHOD AND MATERIALS

Two different 3D finite element models were created. Each model contained cortical bone, cancellous bone, periodontal ligament, cement, and enamel. Additionally one of the models contained a two-retainer zirconium dioxide RBFPD while another contained a single-retainer zirconium dioxide RBFPD. A 100 N force was applied at 45 degrees 2 mm below the incisal edge of the palatal surface of the pontic. In each model, Von Mises stress distribution was evaluated.

RESULTS

Maximum Von Mises stress values in RBFPD with a single retainer and two retainers were 1.13 MPa and 1.23 MPa, respectively. Von Mises stress was concentrated at the interface between pontic and retainer for RBFPD with two retainers.

CONCLUSION

Zirconium dioxide RBFPD with a single retainer and two retainers exhibited similar stress concentrations between pontic and retainer. However, the use of a single retainer for RBFPDs prevented stress concentration at the interface between retainer and pontic.