The Study On The Friction And Wear Property Of Dental Zirconia Ceramics Between Two Kinds Of Sintering Methods After Different Surface Treatments

Objective:The purpose of this study was to evaluate the wear of antagonist and the friction and wear property of dental zirconia ceramic between microwave sintering and conventional sintering after polishing and grinding.Maternal and methods:20 cuboid specimens were fabricated from Lava brand zirconia.10 specimens were sintered using conventional sintering method according to the manufacturer's instructions.The maximum temperature was 1500? and the dwelling time was 2 hours.10 other specimens were sintered using microwave sintering method.While the maximum temperature was 1420? and the dwelling time was half an hour.Then these specimens were randomly assigned(n=5) according to the surface treatment received,that is grinding or polishing. Surface roughness and profile tester was used to measure the roughness of the specimens.The wear test was performed at CFT-1 type material surface performance comprehensive tester and the antagonist was steatite ceramic.The rotation diameter was 8 millimeter and rotation speed was 200r/min for 3600 seconds under a 5 N load.The friction coefficient curve was recorded automatically. The zirconia ceramic and steatite ceramic were weighed by electronic balance before and after the test.Finally,the optical microscope was used to observe the surface morphology of zirconia ceramic and steatite ceramic.Field emission scanning electron microscopy(SEM) was used to observe microstructure of zirconia between two kinds of sintering methods.Results:The friction coefficient of ground zirconia was higher than that of polishing zirconia.The wear volume of zirconia and antagonist increased according to sintering methods and surface treatment as follows:microwave sintering polished group,conventional sintering polished group,microwave sintering ground group,and conventional sintering ground group.Different surface treatments influenced the wear volume of zirconia and steatite ceramic,while sintering methods didn't influence the wear volume of zirconia and steatite ceramic.Optical microscopy showed that ploughed surface was obvious in zirconia.The wear surface of steatite ceramic against polishing zirconia had cracks and plough,while the wear surface of steatite ceramicagainst ground zirconia mainly had plough.Scanning electron microscopy showed that conventional sintered and microwave sintered zirconia had sintered compactly,while the grains of microwave sintered zirconia were smaller and more uniform.Conclusion:There was not statistically difference in the friction coefficient and wear resistance of zirconia between two kinds of sintering methods and the wear of antagonist.However,compared with ground zirconia,the friction coefficient and the wear volume of antagonist were smaller and the wear resistance was better in polished zirconia.The main wear type of zirconia was the abrasive wear.The main type of steatite ceramic was fatigue wear and abrasive.