This study analyzed the biomechanical behavior of rigid and non-rigid tooth-implant supported fixed partial dentures. Different implants were used in order to observe the load distribution over teeth, implants, and adjacent bone using three-dimensional finite element analysis. A simulation of tooth loss of the first and second right molars was created with an implant placed in the second right molar and a prepared tooth with simulated periodontal ligament (PDL) in the second right premolar. Configurations of two types of implants and their respective abutments, i.e., external hexagon (EX) and Morse taper (MT), were transformed into a 3D format. Metal-ceramic fixed partial dentures were constructed with rigid and non-rigid connections. Mesh generation and data processing were performed on the 3D FEA results. Static loading of 50 N (premolar) and 100 N (implant) were applied. When an EX implant was used, with a rigid or non-rigid connection, there was intrusion of the tooth in the distal direction with flexion of the periodontal ligament. Tooth intrusion did not occur when the MT implant was used independent of a rigid or non-rigid connection. The rigid or non-rigid connection resulted in a higher incidence of compressive forces at the cortical bone and stress in the abutment/pontic area, regardless of whether EX or MT implants were used. MT implants have a superior biomechanical performance in tooth-implant supported fixed partial dentures. This prevents the intrusion of the tooth independent of the connection. Both types of implants that were studied caused a greater tendency of compressive forces at the crestal area.
The effect of implant design on the stress distribution in a three-unit implant-supported distal cantilever fixed partial denture: A three-dimensional finite-element analysis
