Abstract： Malocclusion is the third most common disease in the human oral cavity, closely behind caries and periodontal diseases. Along with the cultural and socio-economic progress, demands for orthodontic treatment is increasing year by year. However, the early stage caries, a most common complication in patients receiving orthodontic treatment using fixed appliances, has become a serious challenge to the prevention of dental caries and the esthetic outcome of orthodontic treatment. It deserves both dental workers and patients to pay attention and to take preventive and therapeutic measures on this issue.