Biophysical and microbiologic studies of "heavy" and "light" plaque formers.

In order to trace factors possibly influencing initial bacterial colonization of tooth surfaces, a multiple linear regression analysis was performed on the present results as well as on those from certain clinical and biochemical studies previously performed in the same subjects. No statistically significant differences were observed between the two groups of plaque formers for the individual parameters. The multiple regression analysis showed, however, that the calculated work of adhesion for two polar and one non polar test liquid, the rate of unstimulated salivary secretion, morphologic differences in the dento-gingival areas of maxillary premolars and saliva-induced aggregation of S. mitior were crucial for about 90% of the variation in the number of CFU colonizing tooth surfaces after both 2 and 6 h. Both electrostatic and van der Waal's forces, as well as salivary flow conditions could thus have influenced the initial attachment of bacteria to the test surfaces. It is concluded that saliva including its suspended microorganisms could be looked upon as being a colloidal biological system, and if so, the initial bacterial colonization of tooth surfaces should follow known, general biophysical laws.