The effect of periodontal treatment on the salivary bacterial load and early plaque formation

Aim: The purpose of the present study was to investigate in periodontitis patients the relationship between the number of bacteria in the saliva and the amount of de novo plaque formation before and after treatment.Methods: At baseline, before any treatment was provided, patients rinsed with 10 ml sterile saline. After professional tooth cleaning the patients were instructed to abolish all tooth cleaning procedures for the subsequent 24 h. After this period, the rinsing procedure was repeated and the amount of de novo plaque was assessed. Three months after the initial periodontal therapy was completed the experiment was repeated. The microbiological evaluation of the rinsing samples was carried out by means of phase contrast microscopy and anaerobic culturing.Results: After treatment the amount of de novo plaque was less compared to before treatment, 0.40 and 0.65 respectively. Both before and after treatment more de novo plaque was present at sites with inflammation than at healthy sites. In order to evaluate the contribution of the numbers of salivary bacteria to the amount of de novo plaque formation an analysis was carried out for healthy sites. This analysis included only healthy sites as determined before treatment and the same sites after treatment. The results showed a significant reduction in the de novo plaque formation after treatment (0.49 before and 0.22 after treatment). Phase contrast microscopic evaluation showed that the number of bacteria in the rinsing samples after treatment was less than before treatment. After treatment also a reduction was found in the prevalence of Prevotella intermedia, Tannerella forsythensis and Peptostreptococcus micros in the rinsing samples.Conclusion: The present study confirms the observation in the literature that the periodontal condition is of major importance in the rate of de novo plaque formation. In addition, the results suggest that the number of bacteria in the saliva may play a role.