Aim: White spot lesions (WSLs) occur frequently after fixed orthodontic treatment. This in vitro study was undertaken to compare the efficacy of 2.26% fluoride varnish, 1.23% APF gel, 0.21% fluoride toothpaste and 0.04% sodium fluoride mouthwashes in preventing enamel demineralization around orthodontic brackets in extracted premolars.

Materials and methods: The sample for this study included 100 premolars free of caries and enamel cracks. They were divided into five groups of 20 samples each. Group 1 (FV): light-curable Fluoride varnish (Clinpro™ XT 3M ESPE, Pymble, New South Wales, Australia), group 2 (FG): 1.23% APF gel (Patterson NE. International, USA), group 3 (FTP): 0.21% w/w sodium fluoride toothpaste with tri-calcium phosphate (Clinpro™ Tooth Crème, 3M ESPE, Australia), group 4 (FMW): sodium fluoride 0.044% (w/v) mouthwash (Colgate® Phos-Flur® Ortho Defense Rinse, Colgate-Palmolive, NY) and group 5 (C): control. The samples were subjected to laboratory pH cycling. The demineralization changes in the enamel were assessed before the start of the experiment and after 14 days.

Results: There was a significant change in the mean Diagnodent score value (p <0.001) in all groups from day 1–day 14. The mean values were significantly different among groups at day 1 (p = 0.002), day 14 (p = 0.001) and also the change from Day 1 to Day 14 was significantly different among Groups (p = 0.001). The least change in the mean value from baseline to 14 days was seen in group 1 (FV) followed by group 3 (FTP), group 2 (FG), and group 4 (FMW) and then the group 5 (C).

Conclusion: All the topical fluorides tested were able to reduce the demineralization when compared to the control group under similar testing conditions, but to varying degrees. light-curable fluoride varnish outperformed all the topical fluorides followed by 0.21% w/w dodium fluoride toothpaste with tri-calcium phosphate, 1.23% Acidulated phosphate fluoride gel and sodium fluoride 0.044% (w/v) mouthwash. The control group where no topical fluoride was applied showed the least resistance to demineralization.

Clinical significance: Within the limitations of this study, routine application of light cured fluoride varnish (Clinpro) can be recommended to prevent enamel demineralization to prevent white spot lesions in patients receiving orthodontic treatment.