Discoloration of restorative materials after bleaching application.
OBJECTIVE
The esthetic application of bleaching materials has gained popularity, with consequences for teeth and restorative materials. The aim of this investigation was to evaluate the influence of different bleaching agents with varying peroxide concentrations on restorative materials.


METHODS
The color behavior, Vickers hardness, and surface roughness were determined on different restorative materials and bovine enamel. Cylindric samples of two fine hybrid composites, one microfilled composite, one compomer, and one ormocer were bleached for two 2-hour periods with three commercial and three experimental bleaching agents with varying peroxide concentrations. The properties were determined before and after bleaching. As a control, all materials were investigated without bleaching after a 14-day storage.


RESULTS
The restorative materials showed maximum changes in Vickers hardness of 44, maximum changes in surface roughness of between 0.2 and 0.7 microm, and a maximum discoloration of deltaE = 6.8. A statistically significant deterioration of hardness, combined with the highest discoloration, was found for the microfilled composite and the compomer. Different bleaching systems showed varying effects on surface roughness.


CONCLUSIONS
Bleaching resulted in a deterioration of the restorative materials, indicated by a decrease of hardness and an increase in surface roughness. Generally, bovine enamel showed significantly higher discoloration compared to the restorative materials.
Rosentritt
Martin
M
Department of Prosthetic Dentistry, University Clinics, University of Regensburg, Germany. martin.rosentritt@klinik.uni-r.de
Lang
Reinhold
R
Plein
Tobias
T
Behr
Michael
M
Handel
Gerhard
G
D000818:Animals; D002417:Cattle; D002516:Ceramics / Q000737:chemistry; D003116:Color; D020770:Compomers / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003743:Dental Enamel / Q000187:drug effects / Q000473:pathology; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D006244:Hardness; D008422:Materials Testing; D063225:Organically Modified Ceramics; D016877:Oxidants / Q000737:chemistry*; D010545:Peroxides / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013053:Spectrophotometry; D013499:Surface Properties; D013997:Time Factors; D014073:Tooth Bleaching
D020770:Compomers; D003188:Composite Resins; D003764:Dental Materials; D063225:Organically Modified Ceramics; D016877:Oxidants; D010545:Peroxides; D012821:Silanes