Enamel Remineralization Behavior of Coating Materials via Polarized Light Microscopy

Objectives:  Characterize the remineralization behavior of enamel lesions after a toothbrushing regimen, where the lesion is treated with either a rosin-based varnish applied as a coating over the lesion or an experimental resin-modified glass ionomer material applied adjacent to the lesion.

Methods:  

Extracted human molars with artificial caries-like lesions were sectioned longitudinally into 100µm sections; then photographed via PLM with imbibing media of water (n_D=1.33; showing >5% porosity), followed by an imbibing media of Thoulet's 1.41 solution (n_D=1.41; showing >10% porosity).  Acid-resistant varnish was applied to all surfaces, leaving only the external tooth surface with lesion exposed.  Three treatments were applied:  untreated control group (UNTR); lesion coated with Colgate™ Duraphat™ Fluoride Varnish (DUR); experimental resin-modified glass ionomer material EXM-713 placed adjacent to the lesion (EXM-ADJ).  The sections were brushed with water daily for thirty days.  The acid resistant varnish was removed; sections imaged via PLM again.  The lesion body area was quantified with a computerized imaging system.  The percent remineralization was calculated from the lesion area before and after.  The data were analyzed via one-way ANOVA and compared with Fisher's T-test (p<0.05).

Results:   Percent remineralization (stdev).  Within each imbibition set, superscript letters denote groups that are not statistically different.

Conclusions:

A resin-modified glass ionomer coating applied adjacent to an enamel lesion resulted in enhanced remineralization compared to an untreated control; a conventional rosin-based fluoride varnish applied over the lesion was not statistically different from the control.

This research was supported, in part, by 3M ESPE.