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Published on: February 23, 2017
In Vitro Effects of Nano-hydroxyapatite Paste on Initial Enamel Carious Lesions
Fabíola Galbiatti de Carvalho1, Basílio Rodrigues Vieira2, Rogério Lacerda Dos Santos2
1Department of Clinical and Social Dentistry, at Federal University of Paraíba, João Pessoa, Paraíba, Brazil.
Purpose:
The purpose of this study was to analyze the protective effect of remineralizing agents on enamel caries lesions using surface Knoop microhardness testing (KHN) and atomic force microscopy (AFM).
Methods:
Forty-eight human enamel blocks were assigned to four groups (N=12): (1) control (without agent); (2) fluoride varnish (Duraphat); (3) nano-HAP paste (Desensibilize Nano P); and (4) casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (MI Paste Plus). Incipient caries-like lesions were artificially developed. Cariogenic challenge (pH-cycling) was performed for seven days. The pastes were applied before each immersion in demineralization solution, and the varnish was applied only once. KHN values were obtained at baseline, after incipient enamel lesion, and after challenge. The percentage of surface hardness recovery (%SMHR) was performed, and the surface morphology was evaluated by atomic force microscopy (AFM). ANOVA, Tukey's, and student paired t tests were applied at P<.05.
Results:
After the cariogenic challenge, the nano-HAP group showed significantly higher KHN and %SMHR values than varnish. The CPP-ACP group showed no increase in KHN. The nano-HAP group showed, via AFM, a protective layer formation with globular deposits on the surface.
Conclusion:
SMHR and AFM morphology revealed that nano-hydroxyapatite paste showed a protective effect against in vitro enamel caries development.
