Comparative Study on the Effect of Calcium Carbonate and Covarine on the Enamel Structure of Human Teeth (in Vitro Study)

Toothpaste is a major preventive to enamel surface. CaCo3 as one of abrasives in bleaching toothpastes has an antibacterial effect. A new optical technique is to use covarine blue in bleaching toothpastes. Objectives: Comparison between CaCo3 and covarine blue toothpastes on enamel structure, minerals content and microhardness. Methodology: 48 human premolars divided into three groups: Group I :16 premolars preserved in distilled water. Group II :16 premolars brushed by CaCo3 gel. Group III :16 premolars brushed by covarine gel. Buccal surface of all premolars was brushed electrically and each group was subdivided into 2 subgroups, one examined after 3 weeks and the other after 7 weeks.Enamel was then assessed by: scanning electron microscope (SEM), energy dispersive x-ray analyzer (EDXA) and microhardness tester.Results: SEM: Obvious precipitation of calcium particles on enamel surface in CaCo3 group. Covarine blue group showed almost the same findings as control group except for few cracks.EDXA: After 3 weeks the highest C/P wt. % was recorded in CaCo3 group and covarine blue group respectively, while there was no difference in Ca % in both groups. After 7 weeks P % was the highest in CaCo3 group. There was no statistical significant difference between all groups regarding weight % of calcium and carbon.Microhardness: CaCo3 group represented an increase in the difference of microhardness from 3 to 7 weeks.Conclusions: CaCo3 toothpaste caused precipitation of calcium particles on tooth surface and increase the microhardness of enamel in comparison to covarine blue.