Human Enamel Remineralization by Red Seaweed Lithothamnion Calcareum

Objectives: Fluorides have been systematically used to control the mineral imbalance between mineralized dental hard tissues and surrounding oral biofluids. Our recent discovery that the extract of red-seaweed Lithothamnion calcareum (Lc) can prevent in-vitro demineralization of human enamel as effectively as fluorides is encouraging. Building upon such a finding, this study investigated the ability of Lc to remineralize artificial-demineralized enamel.
Methods: Twenty-eight de-identified caries-free human canines were collected. Enamel fragments (1.5mm²) were obtained from buccal and lingual teeth surface and included in acrylic. After being polished, specimens’ initial surface microhardness (ISH) was measured. Specimens were submitted to pH-challenge cycle, staying in demineralization solution (pH 4.5, @37^oC) for 6hrs followed by storage in remineralization solution (pH 7.4, @37^oC) for 18hrs. After 1-week, the microhardness of all artificially-demineralized enamel (ADSH) samples was measured. Specimens were randomly assigned to one of four following treatments [5mins, 2x/day, under agitation, 37^oC and for 14 days] (n=10/group): reverse-osmosis-water (negative-control); 0.05% sodium fluoride (positive-control); 0.02%Lc (Lc) or 0.02%Lc+1%BAG65 (Lc+BAG65) [where: BAG65=bioactive glass 65%-silica fluoride-free]. Between treatments, specimens remained in remineralization solution. Specimens’ final surface microhardness (FSH) was assessed. The percentage of surface microhardness recovery (%SHR) was calculated as: %SHR=[(FSH−ADSH)/(ISH−ADSH)]×100. Data were analyzed by ANOVA and Tukey tests (a=0.05).
Results: Data fitted into a normal distribution. Lc-treatment (without or with BAG65) promoted significant increase of %SHR of artificial-demineralized enamel by 60% (Lc) and 70% (Lc+BAG65). No statistical difference was shown between Lc and Lc+BAG65 (p=0.11), but both treatments enhanced significantly more the %SHR of artificial-demineralized enamel compared to negative- and positive-control (p<0.01). No significant differences were found between negative- and positive-control treatments.
Conclusions: Corroborating our findings on the ability of Lc-treatment to prevent in-vitro enamel demineralization, we conclude that the combination of Lc+BAG65 should be further explored as an alternative to promoting enamel remineralization.