Evaluation of remineralization potential and cytotoxicity of a novel strontium-doped nanohydroxyapatite paste: An in vitro study

BACKGROUND: The focus of caries management has shifted to the early detection of caries and noninvasive methods of management of incipient lesions with novel remineralizing agents. AIM: The aim of this study is to evaluate and compare the remineralization potential of a novel laboratory synthesized strontium-doped nanohydroxyapatite (SrnHAp) paste to a commercially available regular dentifrice. MATERIALS AND METHODS: Sixty enamel specimens (4 mm × 4 mm × 1 mm) were divided into two groups based on the type of dentifrice applied: Group I – regular toothpaste and Group II – SrnHAp paste. Calcium/phosphorous ratio of all sound specimens was evaluated using Scanning Electron Microscopy-Energy Dispersive X-ray analysis. Samples in both groups were subjected to demineralization, and the calcium/phosphorous ratio was analyzed. The samples were then subjected to remineralization using the specific agents in each group, and the mean calcium–phosphorus ratio was assessed. Cytotoxic evaluation of both pastes was done by direct microscopic observation and MTT assay. STATISTICAL ANALYSIS: Comparison of mean calcium and phosphorous values of sound enamel, demineralized, and remineralized specimen in Groups I and II was done using the one-way ANOVA and Tukeys post hoc test. Intergroup comparison after remineralization was done using the Student's t-test. RESULTS AND CONCLUSION: Group II showed higher remineralization potential than Group I and was statistically significant. Cytotoxicity of novel paste was less compared to the regular toothpaste. SrnHAp showed better remineralization than regular toothpaste and can be considered for enamel repair in incipient carious lesions.