[The study of the colorimetric characteristics of the cobalt-chrome alloys abutments covered by four different all-ceramic crowns by using dental spectrophotometer].
OBJECTIVE
This study aims to evaluate the optical data of the different sites of the cobalt-chrome (Co-Cr) alloy abutments covered by four different all-ceramic crowns and the color difference between the crowns and target tab using a digital dental spectrophotometer.


METHODS
Ten Co-Cr alloy abutments were made and tried in four different groups of all-ceramic crowns, namely, Procera aluminia, Procera zirconia, Lava zirconia (Lava-Zir), and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic. The color data of the cervical, body, and incisal sites of the samples were recorded and analyzed by dental spectrophotometer. The CIE L*, a*, b* values were again measured after veneering. The color difference between the abutments covered by all-ceramic crowns and A2 dentine shade tab was evaluated.


RESULTS
The L* and b* values of the abutments can be increased by all of the four groups of all-ceramic copings, but a* values were decreased in most groups. A statistical difference was observed among four groups. After being veneered, the L* values of all the copings declined slightly, and the values of a*, b* increased significantly. When compared with A2 dentine shade tab, the ΔE of the crowns was below 4.


CONCLUSIONS
Four ceramic copings were demonstrated to promote the lightness and hue of the alloy abutments effecttively. Though the colorimetric baseline of these copings was uneven, veneer porcelain can efficiently decrease the color difference between the samples and thee target.
Yifan
Y
Chen
Hongchun
H
Liu
Yukun
Y
Meng
Yonglie
Y
Chao
Changhong
C
Liu
D002516:Ceramics; D002858:Chromium Alloys; D003035:Cobalt; D003116:Color; D003124:Colorimetry; D003442:Crowns; D003764:Dental Materials; D003776:Dental Porcelain; D017267:Dental Prosthesis Design; D006801:Humans; D016876:Metal Ceramic Alloys; D014025:Titanium; D015040:Zirconium
D002858:Chromium Alloys; D003764:Dental Materials; D016876:Metal Ceramic Alloys; C077451:Procera; C493120:lithia disilicate; D003776:Dental Porcelain; D003035:Cobalt; C023506:Glass ceramics; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide