Purpose: The aim of this study was to determine the changes of salivary flow rate, pH, buffering capacity, total antioxidant capacity and changes in streptococci and lactobacilli counts at baseline, 1 month and 6 months of fixed orthodontic treatment. Materials and Methods: An unstimulated salivary sample was collected from 30 out of 43 patients who were in need of fixed orthodontic treatment (mean age 17.8 ± 5.01 years). Salivary samples were collected from the patients before the placement of fixed orthodontic appliance (Gemini MBT 0223M) at 1 month and 6 months following start of the treatment. Samples were tested for significant changes in flow rate, pH, buffering capacity, total antioxidant capacity and streptococci and lactobacilli counts. Results were compared using ANOVA. Results: The study results showed that orthodontic appliances significantly changed the unstimulated salivary flow rate (p 0.05) (baseline: 0.40 ± 0.11, 1 month: 0.45 ± 0.09, 6 months: 0.44 ± 0.07) and buffering capacity (p 0.05) (baseline: 5.01 ± 0.50,1 month: 3 .98 ± 0.78, 6 months: 4.02 ± 0.78) at the end of 1 month and 6 months whereas lactobacilli count showed significant changes at the end of 6 months (p 0.05) (baseline: 6.20 ± 2.07, 1 month: 7.09 ± 3.78, 6 months: 7.85 ± 1.88). The pH, total antioxidant capacity and streptococci counts did not show any significant changes during the study period. Conclusion: It appears that 6 months of treatment with fixed orthodontic appliance resulted in a significant increase in unstimulated salivary flow rate and lactobacilli counts, whereas buffering capacity decreased significantly during the study period. Schlagwörter: lactobacilli, orthodontic appliance, saliva