Occurrence of haemophili in dental plaque and their association with neuraminidase activity.

The mean concentration of haemophili in 31 specimens of plaque was 1.23 times 10(6) per milligram or approximately 4.4% of the viable bacteria present. Occurrence of different species was similar to saliva with Haemophilus parainfluenzae constituting 87.8%. Most haemophili produced neuraminidase and appeared to be primarily responsible for the small amounts of this enzyme in plaque.