Orthodontic patients with fixed appliances have difficulty to keep their daily oral care due to orthodontic bands, brackets and arc wire. Therefore, the prevalence and severity of dental caries during orthodontic treatment is increasing significantly. Because of Streptococcus mutans (S.mutans) is one of the most important factor for dental caries, the aim of this study was to compare evaluation of efficiency of Ozone and mouth rinses against Streptococcus mutans (S.mutans) numbers in the saliva of these patients.