White spot lesions after fixed appliance treatment-Can we expect spontaneous long-term (≥15 years) improvement?

Objective: To investigate the extent to which post-orthodontic white spot lesions (WSLs) change in appearance over a period of ≥15 years and whether an association with caries data exists.

Subjects and methods: Seventy-two patients treated with a Herbst-Multibracket appliance at age 14.0 ± 2.7 years for 20.1 ± 5.1 months who attended a recall 18.3 ± 2.9 years post-treatment. Post-treatment (T1) intraoral photographs were assessed by a panel of five dentists using a modified version of the WSL-Index by Gorelick. For affected incisors, photographs from before treatment (T0) and recall (T3) were evaluated. In addition, the WSL-Change Index by Pancherz and Muehlich was assessed for all adequately visible incisors considering T1, T2 (if available), and T3. Radiographic (T0, T1, and T2-if available) and clinical (T3) MFT data were used.

Results: 37.5% of the patients exhibited WSLs on ≥ 1 incisor at T1; in total, 81 incisors (14.9%) were affected. At T3, 48% of the WSLs had improved. The modified WSL-Index decreased from 1.2 ± 0.4 to 0.8 ± 0.6 (P < .001), with a score 0 in 28% of the previously affected incisors. When comparing T2 vs. T3, additional improvement after T2 occurred in 11% of the teeth. While no difference existed at T0, the MFT values at T1, T2, and T3 were higher (P ≤ .05) in patients with WSLs at T1 than in those without.

Limitations: The homogeneity of the subjects was limited and no patient-reported outcome was assessed.

Conclusions: Long-term, post-orthodontic WSLs showed spontaneous full recovery in 28% and improvement in 48% of the teeth. Patients affected with WSLs exhibited higher post-treatment MFT values.