Effect of silver and fluoride ions on enamel demineralization: a quantitative study using micro-computed tomography

Abstract

BACKGROUND: This study aimed to investigate the effect of silver and fluoride ions on demineralization of enamel. METHODS: The coronal parts of 40 extracted sound premolars were prepared into tooth blocks. An unvarnished occlusal surface window (OW) and a flat buccal/lingual surface window (FW) were created for each tooth by covering all other surfaces with an acid-resistant varnish. These blocks were randomly allocated into four groups of 10 blocks each and immersed in respective solutions for 5 minutes: Group 1--2.36 M silver fluoride; Group 2--2.36 M potassium fluoride; Group 3--2.36 M silver nitrate; and Group 4--deionized water. After 7-day immersion in a buffered demineralization solution at pH 4.4, micro-CT scans were taken. RESULTS: Mean lesion depth in the FW area for tooth blocks in AgF, KF, AgNO(3) and control groups were 0 mum, 3.3 +/- 10.3 mum, 156.3 +/- 30.8 mum, and 173.6 +/- 48.6 mum, respectively (p < 0.001). The difference in mean lesion depth between the AgNO(3) and control groups was not statistically significant (p > 0.05). Similar OW and FW lesions were observed in tooth blocks in the AgNO(3) and control groups. CONCLUSIONS: Topical application of a 2.36 M fluoride solution can inhibit demineralization of enamel while topical application of silver ions has little effect.