Factors affecting mercury release from dental amalgam exposed to carbamide peroxide bleaching agent.
OBJECTIVE
To assess, in vitro, the effects of aging and surface polishing on mercury release from dental amalgams exposed to 10% carbamide peroxide at two pH levels.


METHODS
Samples of fresh and aged amalgam, polished and unpolished, were treated with 10% carbamide peroxide at pH 4.5 and at pH 6.5 for periods of 1, 4, 7, 10 and 13 days. At each time period, mercury concentrations in solution were measured using a cold-vapor atomic absorption mercury analyzer system and compared to control samples treated with phosphate buffer.


RESULTS
Amalgam samples exposed to 10% carbamide peroxide released significantly more mercury in solution than samples exposed to phosphate buffer controls. Mercury release was time-dependent and significantly higher in aged amalgam than in fresh amalgam (P < 0.001). Mercury release was also pH-dependent and higher in unpolished amalgam.
Rotstein
Ilan
I
Division of Surgical Therapeutic and Bioengineering Sciences, University of Southern California School of Dentistry, 925 West 34th Street, DEN 310, Los Angeles, CA 90089-0641, USA. ilan@usc.edu
Avron
Yael
Y
Shemesh
Hagai
H
Dogan
Hatice
H
Mor
Chaim
C
Steinberg
Doron
D
D000704:Analysis of Variance; D000077463:Carbamide Peroxide; D003723:Dental Amalgam / Q000737:chemistry*; D003775:Dental Polishing; D019554:Dental Restoration Wear; D004338:Drug Combinations; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000032:analysis*; D016877:Oxidants; D010545:Peroxides; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives*
D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D003723:Dental Amalgam; D014508:Urea; D008628:Mercury