Improving the fatigue life of produced dental implants by the thread-rolling process

This study was aimed to produce and test dental implants made out of biocompatible commercial pure titanium (Grade 4) material with improved mechanical strength. The implant samples were designed and manufactured in real sizes using both machining and thread-rolling (TR) processes. This study is also discovering the benefits of cold forming (TR) versus machining processes in terms of increased efficient strength and reduced costs. To produce the samples using the TR method, a suitable TR processing bench including a pair of reverse threaded flat dies and relevant jigs and fixtures were designed and manufactured. The produced implant samples were tested with static and dynamic loads considering the requirements of the ISO14801:2016 standards. The obtained results were compared in terms of mechanical strength and fatigue life. Their microscopic structures and micro-hardnesses were examined to realize the effects of the manufacturing processes. In addition, the effects of hardness, surface roughness, and residual stresses on both mechanical strength and fatigue life of the implants were also evaluated. Therefore, the obtained results showed that the TR process is extremely effective to improve the implant strength and fatigue life.