The inhibitory effects of silver diamine fluoride at different concentrations on matrix metalloproteinases

To study the inhibitory effect of various commercially available concentrations of silver diamine fluoride (SDF) solutions on matrix metalloproteinases (MMPs).

Three SDF solutions with concentrations at 38%, 30% and 12% were studied. Two sodium fluoride (NaF) solutions at 10% and 3% were prepared, and they had the same fluoride ion concentrations as 38% and 12% SDF, respectively. Two silver nitrate (AgNO(3)) solutions at 42% and 13% were also prepared, and they had the same silver ion concentrations as 38% and 12% SDF, respectively. Ten samples of each experimental solution were used to study their inhibitory effect on three MMPs, which were MMP-2 (gelatinase A), MMP-8 (neutrophil collagenase) and MMP-9 (gelatinase B) using MMP assay kits. Positive control containing assay buffer at pH 9 and MMPs dilution was used to calculate the percentage inhibition.

The percentage inhibition of 38%, 30% and 12% SDF on MMP-2 were 79%, 60% and 17%, respectively (p<0.001); on MMP-8 were 94%, 85% and 77%, respectively (p<0.001); on MMP-9 were 82%, 65% and 60%, respectively (p<0.001). The percentage inhibition on MMP-2, MMP-8 and MMP-9 by 38% SDF was significantly higher than the corresponding percentage inhibition by 10% NaF and 42% AgNO(3).

Greater inhibitory effect on MMPs was found with higher concentration of SDF solution. SDF had more inhibition on MMPs than solutions of NaF and AgNO(3) containing equivalent concentration of fluoride and silver ions, respectively.