Valutazione della resistenza allo stress compressivo degli impianti OCT-IN e Z1 TBR

Aim Understanding and anticipating the behaviour of a fixture from its loading is important for the success ofosteointegration. The aim of this study is to evaluate, by measuring the compression forces applied and the alterations they induced, the final deformation, the creep and the maximum load before fracture of the components of two types of implants. Materials and methods Fifty implants, 25 Oct-In and 25 Z1, were first analysed at SEM and then tested with dynamometer The parameters set were: maximum load of 2200 N, which was progressively increased until fracture occurred by a speed of 6 mm/minute for Oct-In and of 1mm/ min for Z1 implant, with a waiting time of 300 seconds for the Oct-In and 600 seconds for the Z1 and the limit of deformation was of 0,5 mm. Results Oct-In implants underwent an average final deformation prior to fracture of 0.69 mm, the average creep speed was 0.45 m/sec and the average maximum load was 1810 N. Z1 implants underwent an average final deformation before fracture of 0.25 mm, the overage creep speed was 0,45 m/sec and the anaverage maximum load was 2194 N. Conclusions Oct-In and Z1 implants endure loads superior to the masticatory ones, in particular zirconium showed an average maximum load of almost 400 N higher than that of titanium and about three times greater than the masticatory forces applied by posterior teeth. SEM fractography shows that the fracture of the zirconium ring of Z1 implants is not due to detachment of zirconium but to the fracture of the underlying titanium. therefore zirconium could improve the mechanical characteristics of resistance of the implants.