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

Abstract

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.

Remineralization Induced by Biomimetic Hydroxyapatite Toothpastes on Human Enamel

“…Mg 2+ ions can regulate HAP crystallization, hindering the growth of HAP crystals and thus forming new nano-HAP crystals [67]. Strontium demonstrates desensitizing and remineralization attributes, consequently bolstering enamel integrity [46]. Conversely, silicon manifests heightened remineralization characteristics, conferring resilience against acid-induced degradation [47].…”

“…As in the case of Mg-HAP, strontium can be a substitute for a part of the calcium ions in the HAP structure. Strontium has been shown to possess some desensitizing properties by blocking or reducing the transmission of nerve impulses in the dentin and remineralization properties, thus strengthening the enamel and helping to repair the early stages of tooth decay [46]. When silicon is substituted into the hydroxyapatite structure, the resulting material exhibits enhanced remineralization properties and increased resistance to acid attacks without causing any harm or irritation to the teeth or gums [47].…”

Remineralization potential of strontium-doped nano-hydroxyapatite dentifrice and casein phosphopeptide-amorphous calcium phosphate cream on white spot lesions in enamel following orthodontic debonding – a randomized controlled trial

“…Again, this may be credited to the smaller particle size, which aids in penetrating pores, and the smaller crystal size, which enhances solubility. 9 An evaluation of the remineralising effects of conventional fluoridated toothpaste with nanosized sodium trimetaphosphate was carried out by Danelon et al 28 It was determined that as compared to ordinary toothpaste alone, the inclusion of tailored remineralising substances produced a substantially greater remineralising effect.…”

“…The freshly prepared paste weighed 100 g and contained 50 g of 25 mol% SrnHAp, 30 g of glycerine and sorbitol working as humectants, 2 g of sodium lauryl sulphate serving as detergent, 3 g sodium alginate as binder, and 15 ml of deionized water. 9 The paste was then placed in anopaque tube and utilised in the experiment.…”

“…The cytotoxicity and toxicology assessment of the patented SrnHAp paste has been already established. 9 …”