In vitro effect of fluoride oral hygiene tablets on artificial caries lesion formation and remineralization in human enamel

Abstract

Background: Aim of this in-vitro-study was to assess the remineralization potential of a tooth cleaning tablet with different fluoride content.

Methods: Twenty three caries free impacted third molars were examined, enamel surfaces were wax coated leaving two 3 x 4 mm windows for exposure to demineralization/remineralization cycles. The teeth were randomly assigned to 4 groups of 5 control and 6 experimental teeth. Demineralization by standardised HEC-gel, pH 4.7 at 37 degrees C for 72 h, was alternated by rinsing in remineralization solution, pH 7.0 at 37 degrees C for 72 h, total challenge time 432 h. The negative control group N was treated during remineralization cycles with saline; positive control group P was treated with remineralization solution; experimental group D1 was exposed to remineralization solution containing Denttabs-tablets with 1450 ppm F; experimental group D2 was exposed to remineralization solution and Denttabs-tablets with 4350 ppm F. Each tooth was cut into serial sections and analyzed by polarized light microscopy for assessment of the different zones of white-spot lesions in 3 representative sections. Statistical analysis was based on the Mann-Whitney-Test.

Results: Both control groups N(-) and P(+) exhibited characteristic white-spot lesions. The remineralization and the demineralization inhibition of the lesions increased considerably from N<P < D1<D2. Denttabs-2 administration showed partial/total remineralization including lamination and/or disappearance of the body of the lesion. The different results of all 4 groups were statistically highly significant (p < 0.01) with both tests.

Conclusion: Based on these results the novel Denttabs formulation represents a highly effective oral hygiene product and the remineralization is correlated to the fluoride content.

Figure 1

Setup of the incubation procedure. The wax coated teeth were fixed to metal wires and were hanging in the different incubation media. The incubation media were constantly slowly agitated with a magnetic stirrer.

Figure 2

Appearance of the experimental lesions. White-spot lesions in the control group N (a), remineralization group P (b), experimental group D1 with Denttabs^® 1450 ppm fluoride (c) and experimental group D2 with Denttabs^® 4350 ppm fluoride (d).

Figure 3

Polarized light micrographs of morphological examples of the 4 groups of control and experimental teeth. a) Negative control N: Homogeneous surface zone, demineralized body of the lesion with no laminations; arrow with asterisk = surface zone, double arrow = body of the lesion. b) Positive control P: Homogeneous surface zone, smaller body of the lesion, detectable translucent zone; arrow with asterisk = surface zone, double arrow = body of the lesion. c) Experimental group D1: homogeneous surface zone, small band of the body of the lesion, detectable translucent zone arrow with asterisk = surface zone, double arrow = body of the lesion. d) Experimental group D2: Homogeneous surface zone, disappearing body of the lesion with laminations, broad translucent zone; dotted line with outlined arrow = laminated body of the lesion, arrow = laminations; double outlines arrow = translucent zone.