Fixed appliance orthodontic treatment may affect local saliva secretion; however, there is limited information available about this respect in the literature. Understanding how fixed appliance orthodontic treatment affects local saliva secretion could provide insight on possible contributions of salivary changes towards decalcification. In this study, we found that during the first month of fixed orthodontic treatment, the whole saliva flow rate, upper labial saliva flow rate and concentrations of whole saliva sodium and chlorine increased significantly, while the concentrations of calcium, phosphorous and potassium in whole saliva decreased. However, all these were in normal levels after 3 months. This study demonstrated that saliva flow rate was increased and saliva electrolytes were changed at early stage when placing fixed orthodontic appliances, which was considered due to increased mechanosensation.