Comparison of wear resistance and retention of inner crowns in telescopic crowns made of polyetheretherketone,zirconia,or cobalt-chromium alloy
Aim:To compare wear resistance and retention of inner crowns in telescopic crowns made of polyetherether-ketone(PEEK),zirconia,or cobalt-chromium alloy.Methods:A total of 24 conical metal-based dental prostheses were crea-ted,using cobalt-chromium alloy,zirconia,or PEEK to make 9 inner crowns each,and 24 outer crowns using cobalt-chromi-um alloy.After sandblasting the outer surfaces of all outer crowns and the inner surfaces of all inner crowns for further use.Based on the different materials of the inner crowns,all specimens were allocated into 3 groups:A,B,and C.Each group contained 9 inner crowns and 8 outer crowns.Group A:the inner crown was made of cobalt-chromium alloy.Group B:the in-ner crown was made of zirconia.Group C:the inner crown was made of PEEK.In each group,one inner crown was randomly selected for surface observation using the scanning electron microscope,and the remaining inner and outer crowns were weighed.The inner crowns were cemented to corresponding tooth models,and the metal tooth models and outer crowns were embedded.The retention was measured on a universal testing machine after simulating 10 000 insertion and removal cycles,and the results were recorded at 0,1 000,5 000,and 10 000 cycles.After removing the embedding and cementing materials,the crowns were reweighed,and weight changes were recorded.The surface wear of the inner crowns was observed under the scanning electron microscope.Results:The differences in retention among the 3 groups were significant(P<0.001).With increasing number of cycles,the retention in Group A gradually decreased,which first increased and then decreased in Groups B and C.Before cycling,the retention was highest in Group A,followed by Group B,and lowest in Group C.After 10 000 cycles,the retention in Group A and C was higher than that in Group B.The relative weight loss of the inner crowns in Group C was greater than those in Groups A and B,whereas the relative weight loss of the outer crowns in Group C was lower than those in Groups A and B(P<0.017).After10 000 cycles,the surface roughness of Groups A,B,and C in-creased,with Group C showing more severe surface roughness.Conclusion:PEEK as an inner crown material can provide retention comparable to that of cobalt-chromium alloy and zirconia.However,PEEK's wear resistance is inferior to those of cobalt-chromium alloy and zirconia,although it causes less wear to the outer crown.
万方数据
维普
