Virulence modulation of Streptococcus mutans biofilms by metal ions released from orthodontic appliances

To evaluate the impact of metal ions commonly shed from orthodontic appliances on the virulence of Streptococcus mutans ATCC®25175™ biofilms.

Biofilms were grown in the presence of Ni(2+), Fe(3+), Cr(3+), Co(2+), and a metal ion pool at concentrations similar to those released in saliva of orthodontic patients for 72 hours. Once mature, biofilms were treated for up to 12 hours with 5% glucose.

Ions interfered with the growth of S mutans by reducing its biomass (Ni(2+), Fe(3+), Cr(3+)), raising its rates of sugar metabolism (Ni(2+), Fe(3+), Cr(3+)), and raising its secretion of lactate (Ni(2+), Fe(3+), Cr(3+), pool).

The laboratory data presented here point to the possibility of virulence increase of S mutans by metal ions commonly released during orthodontic therapy.