Antibacterial Properties of Nano Silver-containing Orthodontic Cements in the Rat Caries Disease Model

The purpose of this study was to evaluate the antibacterial properties of experimental nano silver-containing cements（NSCs） using rat caries disease model. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at three different weight ratios to obtain a series of nano silver-containing cements, then two orthodontic cement products and three NSC samples were implanted into rat caries disease model, and their antibacterial properties were evaluated by the scanning electron microscope（SEM）. Moreover, the rat caries disease model were established by inoculating cariogenic bacteria S mutans into antibiotics treated rat mouths and feeding with cariogenic diet. The tested materials were bonded on the surface of the buccal half crowns of the upper fi rst premolar, and then fi xed under the rats＇ front teeth lingual side to acquire enough retention. The SEM results indicated that the growth of streptococcus mutans was very active in group of Transbond XT. One month later, S mutans scattered on the GC Fuji ORTHO LC surface, and then the number signifi cantly increased and arranged in chains after three months. In groups of NSC2, NSC3 and NSC4, the number of S mutans presented the downward trend and tended to disperse individually with the increase of silver nanoparticle content. We may conclude that the incorporation of silver nanoparticle enhanced GC Fuji ORTHO LC the adhesion restrain and killing effect to S mutans.