The hardness and chemical changes in demineralized primary dentin treated by fluoride and glass ionomer cement

Abstract

Background Fluoride plays an important role in the control of dental caries. Aim To evaluate the chemical exchange between restoration of glass ionomer cement of high viscosity (GIC) and primary dentin with application of sodium fluoride (NaF) 2% through changes in hardness from uptake of calcium, phosphate and fluoride. Material and method Class I cavities were prepared in 40 sound primary molars, and the sample was divided into two groups (n=20) according to dentin condition: sound (1) and demineralized (2). Sub-groups (n=10) were formed to investigate the isolated action of the GIC or the association with NaF (F). This in vitro study examined the chemical exchange under two conditions, sound and demineralized dentin (pH cycling), to simulate the occurrence of mineral loss for the caries lesion. G1 and G2 received GIC restoration only; groups G1F and G2F received NaF before GIC restoration. The specimens were prepared for Knoop hardness test and micro-Raman spectroscopy. A two-way ANOVA test (α = 0.05) was used for statistical analysis. Micro-Raman data were qualitatively described. Result Increased hardness was observed in all the sites of direct contact with GIC in sound and demineralized dentin for all groups (p<0.001); no difference was observed in microhardness after application of NaF (p>0.05). In the evaluation of micro-Raman, direct contact between GIC and dentin for sound and demineralized dentin resulted in increased peaks of phosphate. Conclusion The exchange between GIC and demineralized dentin may induce changes of mechanical properties of the substrate, and uptake of mineral ions (phosphate) occurs without the influence of NaF.

Novel Bioactive Zinc Phosphate Dental Cement with Low Irritation and Enhanced Microhardness

“…The low initial pH of some dental cement may lead pulp insult with subsequent post-cementation teeth sensitivity and thus limitation of their use [19]. The increase in calcium and phosphours ions release and microhardness suggest enhancement of mechanical and chemical properties of the dental cements by improvement in mineral precipitation [20].…”

Chlorhexidine gluconate enhances the remineralization effect of high viscosity glass ionomer cement on dentin carious lesions in vitro

“…The demineralization-remineralization cycling was performed based on Dias et al [ 39 ], as derived from Ten Cate [ 40 ]. The samples were immersed in a demineralization solution for 8 h and a remineralization solution for 16 h per day.…”

Effect of Preirradiation Fluoride Treatment on the Physical Properties of Dentin

“…Preirradiation treatment of dentin with CS and MI did not significantly increase the hardness of the dentin surface. Although several studies have demonstrated that the application of fluoride in vivo leads to remineralization of demineralized dentin [35][36][37], the effects of ex vivo application of fluoride varnishes on intact dentin hardness are equivocal and may depend on acidity, fluoride concentration, and carrier (other constituents) of the varnish [38,39]. Investigations of the protective effects of fluoride gels have shown that they are more effective against enamel caries when flouride is present in the oral fluids around the tooth during an acid challenge.…”