Influence of in-office whitening gel pH on hydrogen peroxide diffusion through enamel and color changes in bovine teeth.
OBJECTIVE
To assess the influence of in-office whitening gel pH on whitening efficiency.


METHODS
Hydrogen peroxide diffusion and color changes on bovine teeth were assessed. Three gels with close hydrogen peroxide concentrations but with various pH levels were tested: Zoom 2 (Discus Dental), Opalescence Endo and Opalescence Boost (Ultradent). The pH levels were respectively: 3.0, 5.0 and 7.0. Thirty enamel slices and tooth crowns were used for both studies (n = 10 per group per study). Hydrogen peroxide diffusion through the enamel slices and the tooth crowns was spectrophotometrically recorded every 10 minutes for 1 hour to calculate the diffusion coefficients. Color changes were spectrophotometrically recorded every 10 minutes for 1 hour and quantified in term of CIE-Lab.


RESULTS
The hydrogen peroxide diffusion coefficient through enamel ranged from 5.12 +/- 0.82 x 10(-9) cm2 s(-1) for pH 3 to 5.19 +/- 0.92 x 10(-9) cm2 S(-1) for pH 7. Through tooth crowns it ranged from 4.80 +/- 1.75 x 10(-10) cm2 s(-1) for pH 5 to 4.85 +/- 1.82 x 10(-10) cm2 s(-1) for pH 3. After 1 hour, the deltaE varied from 5.6 +/- 4.0 for pH 7 to 7.0 +/- 5.0 for pH 3 on enamel slices and from 3.9 +/- 2.5 for pH 5 to 4.9 +/- 3.5 for pH 7 on tooth crowns. There was no statistically significant difference between groups for both parameters.
Laboratory of Extracellular Matrix Interface-Biomaterials, Faculty of Dentistry, University of the Mediterranean, Marseille, France. cnpignoly@free.fr
Christian
C
Pignoly
Lila
L
Camps
Guy
G
Susini
Imad
I
About
Jean
J
Camps
D000818:Animals; D002417:Cattle; D003116:Color; D003743:Dental Enamel / Q000187:drug effects* / Q000378:metabolism; D003770:Dental Offices; D004058:Diffusion; D005782:Gels; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D013053:Spectrophotometry; D013997:Time Factors; D058205:Tooth Bleaching Agents / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology*; D019228:Tooth Crown / Q000187:drug effects / Q000378:metabolism
D005782:Gels; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide