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DEPARTMENT OF PROSTHETIC DENTISTRY

MAURICE AND GABRIELA GOLDSCHLEGER SCHOOL OF DENTAL MEDICINE

TEL AVIV UNIVERSITY

TEL AVIV, ISRAEL

FAX: +972-3-6409250E-MAIL: nissandr@post.tau.ac.il

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FEBRUARY 2000 165

Colorimetric assessment of laser and home bleachingtechniquesJones AD, Diaz-Arnold AM, Vargas MA, Cobb DS. J EsthetDent 1999;11:87-94.

Purpose. Laser bleaching techniques have little of the documentation that is available for homebleaching regimens. This study attempted to quantify color changes after application of laser-acti-vated hydrogen peroxide and compared this technique with conventional bleaching with applica-tion of 2 concentrations of carbamide peroxide.Material and methods. Forty adult human, extracted, maxillary central incisors were cleaned andplaced in distilled water for 48 hours. Specimens were mounted in acrylic resin so the middle thirdof the facial surface was placed flat against the measuring head of a colorimeter. Specimens weredivided into 4 groups of 10 and treated with the following bleaching agents: 35% H2O2 (Quick-White laser whitening system), 10% carbamide peroxide (Opalescence, Ultradent Products Ltd),and 20% carbamide peroxide (Opalescence, Ultradent Products Ltd). Before and after treatmentL*a*b* color coordinate measures were recorded for each specimen and the ∆E or color differ-ence values were computed.Results. Color difference of the various types of bleaching was depicted in a series of charts andgraphs outlining changes at 7 days and 14 days of home bleaching. Readings were given for thecolor difference at 7 days and 14 days of laser treatment. After 7 and 14 days, the laser group wasnot statistically different from the control group. The 10% carbamide peroxide group was not sta-tistically different from the laser group after 7 days, but was significantly different after 14 days ofbleaching. The 20% carbamide peroxide group was statistically different from the laser group atboth time intervals.Conclusion. The recommended 1-time application of laser-activated hydrogen peroxide did notdemonstrate any perceivable color change. Exposure to 20% carbamide peroxide produced thegreatest perceivable change in color. 25 References. —ME Razzoog

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