Observation of the effect of different material and diameters of implants anddifferent framework materials on stress distribution i̇n rehabilitation of fulledentulous mandible with tilted implants by finite element analysis

Aim: The aim of this study is to compare the effect of different implant materials and diameters and stresses on stress distribution in all-on-four treatment concept using finite element analysis method. Material And methods: The implants were modeled with zirconia, titanium, chromium cobalt and PEEK framework on the implants of different diameters designed with zirconium titanium alloy and grade 4 titanium placed according to the All-on-four technique in the lower jaw edentulous. anterior implants vertical to the lateral tooth area of the Posterior implants were modeled with a 30 ° inclination in front of the mental foremen. Three different configurations were created according to the diameters of the implants (3.3 mm, 4.1 mm, 4.8 mm) and a total of 24 analyzes were performed according to different implant implants and framework materials. The occlusal forces were applied to be 100N vertical to the midpoint of a foodstuff with a radius of 1 cm. Foodstuff was applied unilaterally and was located between the 2nd premolar and 1st molar teeth on the left posterior side. The loading is designed to stimulate the masticatory force. Results: Maximum and minimum principal stresses in cortical bone were higher than trabecular bone. As the diameter of the implant increased, the stress values in the bone and the implant decreased. Grade 4 implants produced similar compressive and tensile stresses in the bone with alloy implants. However, Von Mises stresses are slightly higher in alloy implants / abutments. When the framework materials are evaluated, the stress and compressive stresses in the bone and the order according to Von Misses stresses in the implant / framework are PEEK> Titanium> Chrome-cobalt = Zirconia. According to Von Misses stresses in the framework the order is Chrome-Cobalt = Zirconia> Titanium> PEEK. viii Conclusions: As the diameter of the implant increased, more uniform stress distribution was observed in bone and implant. Von Mises stress values seen in narrow diameter implants are below the maximum Von Mises and stress / compression stress levels that the implant and bone can withstand. Implants produced from Grade 4 titanium and titanium zirconium alloy showed similar stress distributions in bone around the implant. However, Von Mises stress values of titanium zirconium alloy implants were found to be slightly higher than Ti implants. Framework with high elastic modulus, such as chromium-cobalt and zirconia, have created lower stress values in the bone around the implant/abutment and implant. Key words: Narrow diameter implants, Tilted implant, Finite element analysis, Titanium implant, Titanium zirconium implant