Title: 0454 - Dose-dependent Inhibitory Effects of Silver Compounds on Enamel Demineralisation
Wei-Te Huang (Presenter)
Queen Mary University of London
Paul Anderson, Queen Mary University of London
Saroash Shahid, QMUL
Objectives: To investigate the effects of different concentrations of AgNO3, AgF and Ag[NH3]2F (silver diammine fluoride, SDF) on enamel demineralisation.
Methods: Fifty-four enamel samples were sectioned from caries-free permanent molars and polished using 500 grit sandpapers. Thereafter, samples were nail varnished, leaving a 3 mm X 4 mm window exposed. The samples were then allocated into nine groups (n = 6). These groups were treated with 3.16 M SDF, 3.16 M AgF, 3.16 M AgNO3, 2.36 M SDF, 2.36 M AgF, 2.36 M AgNO3, 0.7453 M SDF, 0.7453 M AgF and 0.7453 M AgNO3, respectively. Initially all samples were individually demineralised by immersing into 50 mL, buffered pH 4.0 acetic acids for 4 h at 37 °C. Next, the samples were topically treated with their assigned application agents with micro-brush for 1 min and then return to the acids for further 4 h demineralisation. Calcium ion selective electrodes (ISEs) were used to monitor the ion concentrations at 1-min intervals during the demineralisation. The percentage reduction in the rate of calcium loss of enamel (PRCLenamel) was calculated, based on the change of Ca2+ release rate. Afterwards, enamel from each group was powdered and scanned with 19F and 31P magic angle spinning-nuclear magnetic resonance (MAS-NMR).
Results: The mean PRCLenamel of all groups is shown in Table 1. The PRCLenamel increased with concentration in the groups treated with SDF and AgF, while decreased in the groups treated with AgNO3. In the spectrums of MAS-NMR, CaF2 and fluorapatite (FAP) were detected in the groups treated with SDF and AgF. Also, formation of CaF2 was predominant over FAP for every group except that treated with 0.7453 M SDF, for which FAP was predominant.
Conclusions: Silver compounds have dose-dependent inhibitory effects on enamel demineralisation. The inhibitory mechanisms of SDF and AgF are associated with the formations of CaF2 and FAP.
|Silver compound concentrations (mol/L)||3.16||2.36||0.7453|
|SDF||65.2 ± 3.3 %||60.9 ± 4.5 %||41.6 ± 2.2 %|
|AgF||65.6 ± 6.2 %||61.0 ± 5.5 %||51.7 ± 3.7 %|
|AgNO3||0.0 ± 5.3 %||4.5 ± 5.9 %||21.9 ± 3.2 %|
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: None