Silver and fluoride ions in remineralization of enamel and dentine

Abstract

Objective: To investigate the effect of silver and fluoride ions in the remineralization of demineralized enamel and dentine lesions. Materials and methods: Extracted sound premolars were cut into cuboidal blocks. Acid-resistant varnish was painted onto each block to cover its surfaces, except two windows, one in enamel and one in dentine. The tooth blocks were placed in buffered demineralizing solution at a pH of 4.4 at room temperature for 96 hours to create lesions. Then they were randomly allocated to one of four groups and immersed in different freshly prepared solutions, Gp1: 2.36mol/L silver fluoride, Gp2: 2.36mol/L potassium fluoride, Gp3: 2.36mol/L silver nitrate, and Gp4: de-ionized water, for 3 minutes and later transferred to a remineralization solution containing calcium and phosphate ions for a 108-hour immersion at room temperature. Micro-CT scans, 2 slices per block, were conducted before and after remineralization. Results: Numbers of scans for Gp1 to Gp4 were 8, 10, 10, and 10, respectively. The mean linear attenuation coefficients (LAC) at 50 um below the surface for the enamel and dentine lesions before remineralization were around 5.1/cm and 2.0/cm for all groups (p>0.05). The increase in LAC for the enamel lesions after remineralization in Gp1 to Gp4 were 1.12/cm, 0.89/cm, 0.82/cm, and 0.54/cm, respectively (ANOVA, p<0.001; Gp1,2 > Gp3,4). The increase in LAC for dentine lesions were 0.96/cm, 0.91/cm, 0.91/cm, and 0.41/cm, respectively (ANOVA, p<0.001, Gp 1,2,3 > Gp4).

Conclusions: Topical application of silver or fluoride ions can promote remineralization of demineralized enamel and dentine lesions.