The presence of fixed orthodontic appliances leads to an increase in the absolute number of salivary Streptococcus mutans, as well as an increase in the percentage of S. mutans. These changes may be responsible for decalcification or white spot formation during orthodontic therapy. Decalcification or white spot formation during orthodontic treatment has been a problem since the introduction of fixed appliances. The white spot lesion is considered to be the precurser of enamel caries. In orthodontics it has been attributed to prolonged accumulation and retention of bacterial plaque on the enamel surface adjacent to the appliances. Plaque retention surrounding orthodontic appliances leads to enamel demineralization caused by organic acids produced by bacteria in the dental plaque. Plaque develops after the placement of a fixed appliance because the appliance often impedes the maintenance of good oral hygiene for the orthodontic patient. The components of the appliance create many new retention areas for microorganisms and impede proper access to the tooth surfaces for optimal cleaning. Decalcification may then occur. White spot formation represents a poor esthetic side effect of orthodontic treatment that may counteract the beneficial results of such treatment. Thus, prevention of white spot formation is important for the orthodontist to consider before, during and after orthodontic treatment for quality treatment result as professional.