Blanqueamiento

Critical Appraisal
EFFECTS OF BLEACHING ON TOOTH STRUCTURE AND RESTORATIONS, PART IV: EFFECTS ON RESTORATIVE MATERIALS Author and Associate Editor Edward J. Swift Jr., DMD, MS

T

ooth whitening has become a common treatment over the last 15 years, and much research has been reported on the effects of bleaching procedures on enamel, dentin, and restorative materials. We are presenting aseries of Critical Appraisals covering recent research in this area. This final installment describes studies regarding the effects of bleaching agents on various types of restorative materials.

T H E E F F E C T O F D I F F E R E N T B L E A C H I N G A G E N T S O N T H E S U R FA C E T E X T U R E O F R E S T O R AT I V E M AT E R I A L S

O. Polydorou, E. Hellwig, T.M. Auschill OperativeDentistry 2006 (31:473–80)

ABSTRACT

Objective: The purpose of this study was to evaluate the effects of an in-office and an at-home bleaching agent on six different esthetic restorative materials. Materials and Methods: The restorative materials used in the study were all A3 shade and included a hybrid composite (Tetric Ceram, Ivoclar Vivadent, Schaan, Liechtenstein), a flowable composite(Tetric Flow, Ivoclar Vivadent), a microhybrid (Enamel Plus HFO, Micerium, Avegno, Italy), a nanofill composite (Filtek Supreme, 3M ESPE, St. Paul, MN, USA), an ormocer (Definite, Dentsply, Konstanz, Germany), and a CAD/CAM

ceramic (Vitablocs Mark II, Vita Zahnfabrik, Bad Sackingen, Germany). Specimens were 4.5 mm in diameter and 2-mm thick. The composite and ormocer specimens were divided intounpolished and polished groups (the latter accomplished with the 3M ESPE Sof-Lex disk series). Each subgroup (for every testing period and bleaching agent) included three specimens. The bleaching materials used were Opalescence Xtra Boost (Ultradent Products, South Jordan, UT, USA), which contains 38% hydrogen peroxide, and Opalescence PF (Ultradent Products), which contains 15% carbamide peroxide.Fifteen percent carbamide peroxide is roughly equivalent to 5% hydrogen peroxide. Specimens were examined using scanning electron microscopy (SEM) at various intervals. SEM evaluations were done at magnifications of 60¥, 200¥, and 2,000¥. For the in-office material, SEM examinations were performed before bleaching, after 15, 30, and 45 minutes of bleaching, 24 hours later, and 1 month later. Forthe at-home material, the examinations were done before bleaching, after 8 and 56 hours of bleaching, 24 hours later, and 1 month later. The specimens were stored in distilled water except during treatment.

© 2008, COPYRIGHT THE AUTHOR J O U R N A L C O M P I L AT I O N © 2 0 0 8 , W I L E Y P E R I O D I C A L S , I N C .

206

DOI 10.1111/j.1708-8240.2008.00179.x

VOLUME 20, NUMBER 3,2008

SWIFT

The SEM evaluations were done by one blinded examiner, who classified surface changes as being none, minor, or major. Minor changes were defined as observable but negligible changes in surface texture. Major changes were defined as being a loss of resin or cracking in the surface in addition to any changes in surface morphology. Results: No major changes were observed for any ofthe polished specimens using either bleaching agent. With Opalescence PF, major changes occurred only on unpolished flowable composite. Minor changes were observed with all of the other unpolished materials and were more likely after the longer bleaching period. With Opalescence Xtra Boost, major changes were observed on Tetric Flow and Filtek Supreme. Some minor changes were observed in the ceramicmaterial with

this bleaching gel but not with the other. Conclusions: The effect of bleaching agents on the surface morphology of esthetic restorative materials is material and time dependent but can be reduced by polishing the materials before bleaching.
C O M M E N TA RY

Possibly, the most clinically relevant finding of this study was that polishing reduces any potential effects of...