Wear and Microhardness of Three Different Types of CAD/CAM Ceramic Materials

Objective: Wear and microhardness of three different types of CAD/CAM ceramics against enamel as an occlusal antagonist were studied. Also, microhardness was evaluated.
Materials and Methods: The three tested ceramics were: Vita Enamic (polymer-infiltrated ceramic), IPS e.max CAD (lithium disilicate ceramic) and Celtra Duo (Zirconia reinforced lithium silicate ceramic). The occlusal antagonists were extracted teeth. Thirty samples were constructed divided into 3 groups according to the type of ceramic used (10 samples each). Then each group was subdivided into 2 subgroups (5 samples each), The first subgroups underwent a microhardness test while the other subgroups were first weighed then subjected to wear test and finally re-weighed again before being subjected to microhardness test.
Results: The results showed a significant difference in weight loss due to wear between Vita Enamic and both IPS e.max CAD and Celtra Duo. There was also a significant difference for the antagonist tooth structure as regard both weight and height loss between Vita Enamic and both IPS e.max CAD and Celtra Duo. Microhardness results showed a significant difference between Vita Enamic and both IPS e.max CAD and Celtra Duo as regard microhardness without and after wear. For all the tested ceramics, there was no significant difference as regard microhardness without and after wear test. Also, there was no significant difference as regard wear and microhardness between IPS e.max CAD and Celtra Duo.
Conclusions: Vita Enamic showed the worst wear behavior and the least abrasiveness to enamel while, IPS e.max CAD and Celtra Duo showed comparable wear behavior and abrasiveness to enamel. Also, ceramic microhardness was not affected by wear for the three tested ceramics.