How Do Innovative Dentifrices Affect Mineral Content of Bleached Enamel? A pilot study

Objectives: To investigate the effect of two dentifrices containing different concentration of bioactive glass with fluoride after using a whitening agent (%40 hydrogen peroxide, HP) on mineral content and surface morphology of enamel.
Methods: Four freshly extracted noncarious human premolars were randomly allocated into four groups. The study groups were: Bleached test brushing with bioactive glass and <600 ppm fluoride containing dentifrice (BioMin F, UK) (BIO), bleached test brushing with bioactive glass and 1450 ppm fluoride containing dentifrice (Sensodyne Repair&Protect, UK) (SRP); bleached control (HP); unbleached control (UC) without toothbrushing. Subsequently, teeth were treated with whitening agent according to the manufacturers’ instructions and were subjected to 45-days brushing according to the allocated groups. The elemental compositions (w%) of Ca, P, F, C, Si, Mg were determined by X-ray photoelectron spectroscopy (XPS) technique at five different points of each sample. The surface morphology was assessed using Scanning Probe Microscope (SPM). The data were statistically evaluated using ANOVA and Tukey post-hoc test (SPSS 25, IBM, USA). (α = 0.05).
Results: XPS failed to show statistically significant differences between the elemental levels (w%) of UC and HP; whilst Si% and F% values were higher in SRP than UC. (p<0.05). When compared to UC and HP, BIO was found to have higher levels of P% and Ca% (P%: BIO: 6.73 ± 1.36; HP: 3.46 ± 2.22; UC: 3.24 ± 1.59), (Ca%: BIO: 9.40 ± 1.80; HP: 5.74 ± 1.54; UC: 5.95 ± 2.17) (p<0.05).
SPM detected surface alterations on bleached and dentrifice-treated teeth.
Conclusions: The significantly higher levels of calcium and phosphate on bleached enamel after application of dentrifice containing bioglass with low concentration of fluoride might indicate the presence of a layer that is rich in calcium and phosphate providing a source for remineralisation.