Colony forming unit levels of salivary Lactobacilli and Streptococcus mutans in orthodontic patients.

The purpose of this study was to compare the levels of Lactobacilli (LB) and Streptococcus mutans (SM) colony forming units (CFU) in the saliva of subjects before and after orthodontic appliance placement. This was a controlled, prospective two-group, two-measurement, clinical trial performed on 64 study patients, 12-15 years old. Subjects in the experimental group were sampled for LB and SM in stimulated saliva collected on the same day but prior to band and bracket placement. The subjects in the control group were sampled on their first screening appointment two months prior to band and bracket placement. The second samples of LB and SM were taken from the experimental and control groups after two months. Saliva was transferred to a selective agar carrier and incubated for 48 hours at 37 degrees C / 99 degrees F. LB and SM colonies forming units were compared with standard densities. The experimental group wearing orthodontic appliances had significantly higher mean LB CFU counts than the control group at the 2 month follow-up (3.25 vs. 2.57, p = 0.0036). The two groups, however, did not show any difference in mean SM CFU counts at the 2 month follow-up (3.0 vs. 3.1, p = 0.66). The results of this study showed that a higher number of CFUs of LB were associated with the group wearing orthodontic appliances after two months and may play a role in the increased levels of plaque seen in many orthodontic patients.