The effects of different materials used in implant supported fixed prosthesis on stress distribution in implant and bone support: A three dimensional finite element study

In this PhD thesis, it was aimed to determine how the stresses occurring around the implant, prosthesis and surrounding bone tissue; it is affected by the the restorative material type, prosthesis design, difference of surrounding bone support and the force angle parameters. Implant-supported restorations are modeled virtually in right lower jaw models with different vertical bone height. Three implants (Institute Straumann® AG, Basel, Switzerland Standard Plus Implant 4.1 RN) were placed in the premolar and molar tooth (5-6-7-) areas. In the first model, all of the implants are embedded in the jawbone. In the second model, threads of the implants are 3 mm open. CAD / CAM supported restorative materials were used in the modeling of implant-supported crowns. These materials are monolithic zirconia (ZirkonZahn Prettau), two different resin infiltrated ceramics (GC Cerasmart and VITA Enamic) and glass ceramic reinforced with lithium disilicate (IPS e.max CAD). Prosthesis designs are in two different forms; splinted and nonsplinted. The direction of the force to be applied is in two different forms, oblique (300) and vertical (900). Force was applied to the buccal tubercles and central fossa. The resulting stresses are evaluated using the three dimensional finite element stress analysis analysis method. According to the analysis results, it has been observed that the application of oblique force causes more stress formation in all cases. It has been observed that the type of restorative material does not significantly affect the stress distribution around the support bone and implant. It has been observed that resin infiltrated crown materials provide less stress in the restoration, especially in the neck area. Combination of the prosthesis design can be preferred in jaws with insufficient bone support, especially in the presence of parafunctional habits, in case of excessive load on the prosthesis and implant.