Research On Wear And Friction Properties Of Nature Teeth And Dental Restorative And Filling Materials

Objective:The aim was to investigate and evaluate the friction and wear behavior between the nature enamel/dentine and eleven kinds of dental restorative and filling materials against the steatite ceramic in vitro.Design and Key Methods:A loading wear test was done in artifical saliva at 37℃using a MMV-1 Vertical universal friction and wear testing machine.a steatite ceramic grinding wheel instead of enamel as the abrasive counterface,whose wear resistance and physical property were similar to nature enamel.Dimensionally standardized experimental metal specimens were casted in cylinder recesses of customized silicone moulds.The rough surface of specimens tested were all undergoed finishing and polishing procedures the same as clinical. All of surface of materials were protected to against abrasion before the test.Teeth samples were prepared from freshly extracted human premolars for orthodontic reasons.Each tooth was sectioned in half in a buccolongual direction,through the buccal cusp tip using a special diamond pope bur with a water-cooled.The volumetric wear rate was calculated from the change of weight.The failure mode on the worn surface was analyzed using scanning electron microscope(SEM) photographs and debris element analysis was carried out by energy dispersive spectrometer.The rigidity value was got by micro-rigidity test device.Results:1.The primary wear mechanism of enamel was fatigue wear,adhesion wear and abrasive wear.Dentine was abrasive wear.Regular changes in the stable friction coefficients of enamel and dentine,numerical value was 0.60-0.75,0.45separately. 2.The primary wear mechanism of metal materials were adhesion wear and abrasive wear.Ni-Cr alloys possessed the lowest mean values for volume loss.The volume loss of Au-Pd alloys and their antagonist were nearest to that of enamel and its antagonist.There were significant positive correlation(r=0.95,P<0.05) between volume loss of steatite and value of alloy rigidity.The coefficients values of Au-Pd alloys were 0.67,Ag-Pd alloys were 0.72,Pure Ti was 0.81,Ni-Cr alloys were 0.85,Ag-Hg alloys were 0.58-0.65.3.The primary wear mechanism of macromolecular materials were adhesion wear.There were no statistical differences between volume loss of dentine and FiltekTM P60 composite resins(P>0.05).The coefficients values of BAYER TEETH were0.50,ENDURATM EETH were 0.38, FiltekTM P60 composite resins were 0.58, FiltekTM Z350 composite resins were 0.65.4.The primary wear mechanism of Vintage-al and Vita-alpha were adhesion wear,abrasive wear and fatigue wear.The volume loss of materials were much lower than that of enamel (P<0.05).The coefficients values were 0.85,0.80 separately.Conclusions:Au-Pd alloys had good surface wear resistance,which were nearest to that of enamel,and were more suitable for dental restoration applications than other three dental metal materials.The wear resistance of FiltekTM P60 composite resins were nearest to that of dentine.The wear resistance of Ni-Cr alloys,Vintage-al and Vita-alpha were much higher than that of enamel.