In-vitro Remineralization Effect of Calcium-Containing Pastes in Enamel Lesions

Fluoride prevents against dental caries primarily by enhancing remineralization of calcium and phosphate into the tooth structure. Some products marketed against tooth sensitivity release calcium, such as MI Paste (GC America), which contains Recaldent (casein phosphopeptide amorphous calcium phosphate), and SootheRX (Omnii Pharmaceuticals), which contains Novamin (sodium calcium phosphosilicate glass). It has been hypothesized that they might also aid in caries remineralization. Objective: Compare the caries remineralization potential of MI paste, SootheRX, 1100ppm sodium fluoride dentifrice (F), and MI paste plus 1100ppm sodium fluoride dentifrice (MI-F). Methods: Seventy-two human enamel specimens were demineralized in a 50% saturated hydroxyapaptite/0.1 M lactic acid/carbopol solution (pH 5.0) for 72-96h; baseline Vickers surface harness (SH) of 25-45. Specimens were then subjected for 20 days to a cyclic remineralization regimen, which consisted daily of a 4-h acid/carbopol demineralization period, four 1-min treatment periods (18 specimens/group; except for F, products were not rinsed off to mimic clinical use), and 20 h in a saliva mixture (pooled human saliva/artificial saliva). The MI-F group was first treated with the 1100ppm NaF dentifrice, rinsed with di-ionized water followed by application of MI paste, with subsequent placement in the saliva mixture without being rinsed. Specimens were then reanalyzed for SH and the change (ΔSH) was calculated (posttreatment- baseline). Results: The F-treated group had significantly (p<0.05) higher ΔSH (Mean±SD= 107.4±27.7) than the other groups; followed by the MI-F group (83.1±31.5). The MI paste (2.7.7±7.7) and SootheRX groups (14.9±7.3) were not significantly different and had the smallest ΔSH. Conclusion: Treatment with 1100ppm NaF resulted in the highest level of remineralization, while the two tested calcium delivery products resulted in significantly less remineralization, even in combination with NaF. This study was supported by a grant from IUSD.