Whitening effect and morphological evaluation of hydroxyapatite materials.
OBJECTIVE
To measure the efficacy of the whitening effect of non-oxidizing and non-acidic nano- and micro-hydroxyapatite materials on the enamel surface and to evaluate the surface changes after treatment.


METHODS
Three hydroxyapatite suspensions and two hydroxyapatite mixtures in dissolvable polymer films were applied to a total of 30 extracted caries-free human premolars. After the last material application, a hydrodynamic shear force was generated and applied for 2 minutes to all teeth to simulate mechanical loading of the surface. The tooth color was measured with a dental spectrophotometer. The mean changes of the L*a*b* values between different measurements in each group were expressed as delta E and were analyzed with ANOVA and the Tukey's post-hoc test.


RESULTS
The groups of the nano-hydroxyapatite, the hydroxyapatite-nanocrystals and the tricalcium-phosphate exhibited significant delta E values between baseline and after hydrodynamic shear force application (P<0.05). In conclusion, the materials used in the study are very promising alternatives to oxidizing bleaching agents.
Dabanoglu
Alp
A
Ludwig Maximilians University, Faculty of Dentistry, Department of Operative Dentistry and Periodontology, Goethe Str. 70, D-80336 Munich, Germany.
Wood
Claudia
C
García-Godoy
Franklin
F
Kunzelmann
Karl-Heinz
KH
D000704:Analysis of Variance; D001641:Bicuspid; D003124:Colorimetry / Q000379:methods; D003799:Dental Stress Analysis; D006801:Humans; D006882:Hydroxyapatites; D008855:Microscopy, Electron, Scanning; D033081:Shear Strength; D013053:Spectrophotometry; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching / Q000379:methods*
D006882:Hydroxyapatites