White lesions after orthodontic treatment: does low fluoride make a difference?

OBJECTIVE: To compare and measure the changes in size of post-orthodontic demineralized white lesion enamel lesions treated with a low fluoride (50 ppm) versus a non-fluoride mouthrinse/toothpaste regime.

STUDY DESIGN: An experimental double-blind prospective randomized clinical controlled trial.

SETTING: A university dental school orthodontic clinic (Sheffield, UK).

PARTICIPANTS: Twenty-six patients identified as having post-orthodontic demineralized white lesions on removal of their fixed appliance. METHOD AND INTERVENTIONS: The participants were randomly and blindly assigned to either a low fluoride mouthrinse/toothpaste treatment regime or an inactive control. Computerized image analysis of calibrated photographic images taken under polarized light were used to measure the lesions.

OUTCOME MEASURES: Lesion size and proportion (DWL%t) and percentage reduction (ADPR) at debond, and at 12 and 26 weeks later.

RESULTS: Five participants dropped out of the study, 12 had the low fluoride regime and 9 did not. As a percentage of the total labial tooth area (DWL%t) the mean size of the lesions at debond was 8.1% (SD 3.7). After 12 weeks the mean size of lesion had reduced to 4.6% (SD 2.6), which was a significant reduction (p=0.03). After 26 weeks the mean size was 3.5% (SD 2.1), which was a very significant reduction (p<0.003). This confirmed statistically that post-orthodontic demineralized white lesions do reduce in size with time reflecting remineralization or other enamel surface changes. Intervention using a test low fluoride mouthrinse/toothpaste combination at 26 weeks showed an average difference percentage reduction (ADPR) of 54.3% (Upper 95% CI=62.08, Lower 95% CI=46.44%) compared with a non-active control combination, which showed an ADPR of 66.1% (Upper 95% CI=77.74, Lower 95% CI=54.51%). This failed to show any differences or therapeutic affect.

CONCLUSIONS: Post-orthodontic demineralized white lesions reduced in size during the 6 months following treatment by approximately half the original size. There was no clinical advantage in using the low fluoride formulation of mouthrinse/toothpaste in this study.