Prevalence of white-spot lesions before and during orthodontic treatment with fixed appliances.

The aim of the study was to determine the prevalence of white-spot lesions (WSLs) in patients with fixed orthodontic appliances. The cross-sectional study sample consisted of three groups of patients: group I, 59 patients treated orthodontically for 6 months; group II, 64 patients treated for 12 months; group 0 (control), 68 patients examined immediately before appliance placement. All groups were treated with a 0.022-inch slot preadjusted appliance and they wore a functional fixed appliance. The presence of WSLs was evaluated by visual examination using the scoring system proposed by Gorelick. The groups were evaluated for differences in the prevalence of at least one WSL using Fisher's exact test, followed by Bonferroni pairwise comparisons. The prevalence of WSLs by tooth type was evaluated with logistic regression (P < 0.05). Intraobserver agreement was assessed by means of the Cohen k statistical method. There were no significant differences in the prevalence of WSLs between patients treated for 6 and 12 months (P = 0.855); however, there were significantly more WSLs in groups I and II than in group 0 (P = 0.000). No significant differences were found between girls and boys (P = 1.000). The mandibular first molars and maxillary lateral incisors were the most affected teeth, in both the treated and untreated groups. The study revealed significant decalcification at 6 months after orthodontic bonding. Considering how quickly these lesions can develop and become irreversible, early diagnosis is of critical importance.