This in-vitro study evaluated the efficacy of tooth whitening using different calcium-phosphate based formulations.
Methods:
90 extracted caries-free human teeth were randomly assigned to 9 groups. They were treated with two different hydroxyapatite preparations (zinc-carbonate-apatite and tricalcium-phosphate) in different concentrations (30wt%, 20wt%, 10wt%).Zinc-carbonate-apatite paste was also used. Colgate® Toothpaste and Elmex® Fluid(amine fluoride included) were used as the positive control. The teeth were brushed for 3min with the materials, left for 5min, rinsed with water and then stored in Evian®mineral water for 24h at 37°C.This procedure was repeated for three times. After the last material application, a hydrodynamic shear force was applied to mimic mechanical loading. L*a*b*-values were collected with a spectrophotometer after each treatment and mean changes of the L*a*b*-values between different measurements were expressed as ΔE.A two-factorial analysis of variance and Tukey’s post hoc test corrected according to Bonferroni were used to identify the differences between either two groups or two time points.
Results:
As the factor "time" and "material*time" were not significant, model 1:ΔE ~ material + time +material*time was refined to model 2:ΔE ~ material.
Material |
ΔE |
Mean±SD |
|
Zinc-carbonate-apatite , 30wt% |
1.70±1.60b,c,d |
Zinc-carbonate-apatite , 20wt% |
0.91±0.50a |
Zinc-carbonate-apatite , 10wt% |
1.03±0.76a |
Tricalcium-phosphate , 30wt% |
1.06±0.75a,b |
Tricalcium-phosphate , 20wt% |
1.03±0.67a |
Tricalcium-phosphate , 10wt% |
2.20±0.90d |
Zinc-carbonate-apatite(paste) |
1.93±0.99c,d |
Colgate® Sensation White |
1.43±0.81a,b,c |
Elmex® Fluid |
1.80±1.10c,d |
“a-d”different superscripts mean statistically significant differences for ΔE in different groups (P<0.05).The same superscripts denote subsets in which values are not significantly different in different treatments (P>0.05).
Conclusions:
Calcium phosphate based formulations which can adhere to the enamel surface and contribute to tooth whitening have a promising application potential.