天然牙和树脂牙体外三体磨粒磨损性能研究

Comparative Study of the Three-Body Abrasive Wear Behavior of Natural Human Teeth and Plastic Teeth

以钛合金作摩擦偶件材料,在往复滑动摩擦磨损试验台上考察了年轻恒牙、老年恒牙以及树脂牙在三体磨粒磨损工况下的摩擦学性能,并与两体磨粒磨损工况下的结果进行了对比.结果表明:天然牙和树脂牙在不同磨损工况下的摩擦磨损行为存在显著差异;在三体磨粒磨损工况下,由于食物浆的润滑和应力分散作用,天然牙的摩擦系数和磨损深度明显比两体磨粒磨损工况下的小,磨损机制主要为擦伤,并伴随剥落;树脂牙的三体磨粒磨损比两体磨粒磨损剧烈,磨损表面呈现犁沟和剥落迹象.

A modified reciprocating friction and wear tester was performed to evaluate the friction and wear behavior of natural teeth and artificial plastic teeth sliding against a TC4 titanium alloy ball in the presence of food slurry as the third body. The wear scars of the natural and plastic teeth were observed using a laser co-focus scanning microscope. It was found that the natural teeth and the plastic teeth all showed different tribological behaviors in two- and three-body abrasion. Namely, the natural teeth had remarkably smaller friction coefficient and wear scar depth under three-body abrasive wear condition than under two-body abrasive wear condition, which was attributed to the lubricity of the food slurry as the third body and its action to de-concentrate the stress. However, the plastic teeth had more severe wear under the three-body abrasive wear condition than under two-body abrasive wear condition, which was attributed to the low hardness and poor mechanical strength of the plastic teeth. Moreover, the natural teeth were characterized by scratch and accompanied delamination under the three-body abrasive wear condition, while the natural teeth were dominated by ploughing and delamination under the three-body abrasive wear condition. This conformed to their different abrasive wear-resistance as well.