[Effect of different dental polishing methods on cobalt-chromium casts surface roughness and accuracy].
OBJECTIVE
To evaluate the effect of different polishing methods on surface roughness and accuracy of cobalt-chromium castings.


METHODS
Five polishing methods were compared: centrifugal barrel polishing, electrical brightening, grinding, grinding+centrifugal barrel polishing and grinding+electrical brightening. 30 specimens (30 mmx 10 mm x l.5 mm) were divided into 6 groups which were cast and polished for surface roughness test.30 upper complete denture bases were cast and divided into 6 groups. The dimensional accuracy between the posterior border of the upper complete denture and model at five different positions were determined by traveling microscope measuring method respectively before and after polishing. One-way ANOVA with SPSS13.0 was used for statistical analysis.


RESULTS
Specimens polished by grinding+centrifugal barrel got the smoothest surface (P < 0.01) with Ra0.19 microm, compared with Ra3.38 microm before polishing. No significant difference of the posterior border gaps between the cast base and model was found (P > 0.05).


CONCLUSIONS
Bases polished by grinding + centrifugal barrel had the smoothest surface. There is no influence of centrifugal barrel polishing on dimensional accuracy of cast upper base.
Wang
Xue
X
Department of Prosthodontics, Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, Shandong Province, China.
Zhang
Xiao-hong
XH
Mu
Jian-gang
JG
Liu
Hong
H
Li
Jing-hua
JH
D002858:Chromium Alloys / Q000737:chemistry*; D003035:Cobalt; D003729:Dental Care; D003775:Dental Polishing / Q000379:methods*; D003819:Denture Bases; D003827:Denture, Complete, Upper; D006801:Humans; D013499:Surface Properties
D002858:Chromium Alloys; D003035:Cobalt