Development of white spot lesion (WSL) is one of the main side effects of fixed orthodontic treatment. The aim of this study was to investigate the incidence of WSL during treatment and to determine the significant factors. 150 patients (78 girls, 72 boys) were randomly selected to determine incipient WSL development. Labial surfaces on pretreatment and posttreatment photographs were scored with a standardized visual scoring system. The prevalence of WSL is 21% before treatment. After treatment, 65% of patients presented WSL. The incidence of patients who developed at least one new WSL during treatment was 55%. Only 35% of patients were free of WSL all the time. Age at start of treatment and oral hygiene were significantly associated with new WSL development (p=0.004 and p=0.018, respectively). Gender and treatment length were not associated with new WSL development.
Conclusion: The incidence of WSL in patients treated with Fixed Appliance Treatment was significantly high, and it appeared that the preventive therapies were insufficient. Clinicians should evaluate the oral hygiene status of patients and if possible, should not begin treatment at an early age.