Enamel remineralization and repair results of Biomimetic Hydroxyapatite toothpaste on deciduous teeth: an effective option to fluoride toothpaste

Abstract

Background: Dental caries is a recognized worldwide public health problem. Despite being one of the most effective strategies against dental caries, the excessive use of fluorine may result in a potential risk of developing dental fluorosis especially in children under age of six. The purpose of this work is to analyze a fluorine-free toothpaste containing Biomimetic Hydroxyapatite to assess enamel re-mineralizing and repairing properties.

Results: The study was performed in vitro and in vivo, comparing the hydroxyapatite toothpaste with two others toothpaste containing different fluorine concentrations. The coating effect of the micro-structured Hydroxyapatite nanoparticles reintegrates the enamel with a biomimetic film reproducing the structure and the morphology of the biologic Hydroxyapatite of the enamel. As demonstrated, the coating is due to the deposit of a new layer of apatite, which presents fewer particles than the natural enamel, not based on the chemical-physical changes occurring in fluorinated toothpastes. Moreover, it shows resistance to brushing as a consequence of chemical bonds between the synthetic and natural crystals of the enamel.

Conclusions: The use of Biomimetic Hydroxyapatite toothpastes has proven to be a valuable prevention measure against dental caries in primary dentition since it prevents the risk of fluorosis.

Keywords: Biomimetic nanocrystals; Carbonate-hydroxyapatite; Enamel remineralization toothpaste; Zn-carbonate hydroxyapatite.

Fig. 1

SEM Image of desiccated Biorepair^® toothpaste

Fig. 2

Different sample preparations. SEM images of sample Br and B1 (a, b), sample F1 (c, d) and sample F2 (e, f) at different magnifications

Fig. 3

SEM micrograph of the artificially demineralized tooth (a ×500, b ×5000)

Fig. 4

SEM images of neutral toothpaste treatment: control group dental surfaces (a, c) patient group dental surface (b, d). Magnification ×1000 a, b. Magnification ×5000 c, d. In b flattened cells of the oral epithelium are showed (arrow)

Fig. 5

SEM images (magnification ×500) of different treatments on dental surfaces. Fluorine 500 ppm toothpaste in control group (a) and patient group (b); Fluorine 1400 ppm toothpaste in control group (c) and patient group (d); Biorepair^® toothpaste in control group (e) and patient group (f). In f flaked off cells from the patient's oral epithelium are present (arrow)

Fig. 6

SEM images (magnification ×5000) of different treatments on dental surfaces. Fluorine 500 ppm toothpaste in control group (a) and patient group (b); Fluorine 1400 ppm toothpaste in control group (c) and patient group (d); Biorepair^® toothpaste in control group (e) and patient group (f)

Fig. 7

Biorepair^® toothpaste additional test SEM images of a control surface before treatment with a common fluorinated toothpaste and b after treatment with Biorepair^®; a and b, magnification ×500, c, d magnification ×1000

Fig. 8

a CFU results of S. mutans treated and not with 5% toothpastes in saline solutions at various times. Bacterial survival is expressed in CFU rate compared to untreated one. Statistical analysis was performed by two-way analysis of variance (ANOVA) method coupled with the Bonferroni post-test. Different letters indicate different statistical significances. b S. mutans cell survival after treatment for 4 h in saline solutions with 1% of toothpastes content. Error bar indicates standard deviation. Statistical analysis was performed by one-way ANOVA method coupled with the Bonferroni post-test (**P < 0.01 compared to the control). c Biofilm biomass analysis on CV stained deciduous teeth. Data are expressed as percentage of biofilm formation relative to control teeth brushed with Neutro-pasta toothpaste. Histograms are the mean of three independent experiments. Error bars indicate SD and statistical analysis was performed by one-way ANOVA method coupled with the Bonferroni post-test (ns not significant). d Photographs of teeth brushed with the different types of toothpaste and stained with CV after S. mutans biofilm growing