Effect of shape of the reinforcing perforated PEEK frame on bearing capacity of a complete removable denture of the maxilla

In this paper, a new model of a perforated three-petal PEEK frame for reinforcing the base of a complete removable denture (CRD) of the maxilla is considered. To increase the mechanical component of the adhesion of the frame, dovetail cutouts were added along the perimeter (edge) of the PEEK frame. To evaluate the effectiveness of the proposed frame shape, numerical modeling of the deformation behavior of the hybrid CRD structure was carried out under conditions of both minimal and ideal adhesion between the frame and the base. The stress-strain state was calculated using the finite element method (FEM) using the Abaqus software (Dassault Systèmes, France). The load-bearing capacity of a hybrid CRD reinforced with the previously developed initial shape of a PEEK frame and a new three-petal shape was compared. To assess the effectiveness of dovetail fasteners, models of developed frames are considered, both with and without this attachment. A number of patterns have been identified for the considered models and their loading conditions. Thus, with perfect adhesion, the original form of the PEEK frame more effectively increases the bearing capacity of the hybrid CRD from 10% to 25%, while the new three-petal shape does so to a lesser extent: from 5% to 15%. With weak adhesion, the initial shape of the PEEK frame reduces the load-bearing capacity in some of the considered loading options by up to 25% (relative to non-reinforced PMMA), including in the presence of dovetail fasteners. It limits its use with weak adhesion of the frame to the base. It is shown that the presence of dovetail fasteners for the original shape of the frame changes the load-bearing capacity both positively and negatively under different loading conditions within 10%. Reinforcing the base with a three-petal PEEK frame (a new form) with weak adhesion to the base does not in all cases of loading increase the bearing capacity of the prosthesis compared to an unreinforced base. However, it does not reduce it, regardless of the presence of dovetail fasteners on the frame. Therefore, it is more suitable for reinforcing the base with its weak adhesion to the frame compared to the original shape of the frame. It is shown that the three-petal shape of the frame is promising for reinforcing the base with weak adhesion when using a frame material with a high modulus of elasticity.