Adherence of oral streptococci to composite resin restorative materials

The frequency of oral streptococcal bacterial isolates detected on composite resin squares attached to maxillary first molars in 12 volunteers was 62.1 per cent. These cocci consisted of Streptococcus mitior (52.8 per cent), S. sanguis (20.2 per cent), S. oralis (8.6 per cent), S. salivarius (1.0 per cent) and S. anginosus (0.3 per cent). An electron microscopic study of these organisms labelled with [3H]thymidine for in vitro adhesiveness to the resin revealed that S. mitior was the most adhesive, and that its pronounced adhesiveness is associated with its characteristic extracellular ultrastructure.