Trial suggests that regular brushing as effective as MI paste or fluoride varnish in reducing white spot lesions post orthodontic treatment

iStock_000002551343XSmall colourful braces on teeth

One of the adverse effects of orthodontic treatment is the development of white spot lesions (WSLs). The incidence of these early carious lesions has been reported to vary between 5-97% . The aim of this trial was to effectiveness of MI Paste Plus and PreviDent fluoride varnish (22,600 ppm of fluoride) with a standard oral hygiene regimen with 1100 ppm fluoride toothpaste in improving the appearance of WSLs after orthodontic treatment.

Patients who had completed orthodontic treatment within the past 2 months with one or more WSLs were randomised to one of 3 groups; Group 1, MI Paste Plus to be applied to each arch twice daily for 8-weeks in addition to usual home care (1100 ppm fluoride toothpaste); Group 2, single application of 0.4mL of 5% fluoride varnish plus usual home care (1100 ppm fluoride toothpaste); Group 3, usual care home care (1100 ppm fluoride toothpaste). Photographs taken at baseline and 8 weeks were assessed by two panels consisting of 5 dental professionals and 5 laypersons in a blinded fashion. The examiners used 0 visual analog scale from 0 to 100 mm (0 mm, no improvement or worsened, to 100 mm, WSL completely disappeared).

  • 135 patients were randomised 115 participants completed the study; 34 in group 1, 40 in group 2 and 41 in group 3.
  • The mean improvements assessed by the professional panel were 21%, 29%, and 27% in the MI Paste Plus, fluoride varnish, and control groups, respectively. While the results from the lay panel were 29%, 31%, and 25%, respectively.
  • There were no significant differences between the active and control arms.

The authors concluded.

MI Paste Plus and PreviDent fluoride varnish do not appear to be more effective than normal home care for improving the appearance of white spot lesions over an 8-week period.


This study was conducted in a number of site in a practice based environment rather than a hospital or university setting.  On of the challenges highlighted by the authors was of the standardisation of the photographic imaging across the sites although training and calibration of the practitioners was undertaken.  An interesting element of this trial is the use of a lay panel to assess the images. This study looks at management of WSLs post treatment,  previously we reported another small trial by Robertson et al  (Dental Elf  9th Nov 2011)  that found that regular application of MI paste in trays during treatment helped prevent the development of WSLs.


Huang GJ, Roloff-Chiang B, Mills BE, Shalchi S, Spiekerman C, Korpak AM, Starrett JL, Greenlee GM, Drangsholt RJ, Matunas JC. Effectiveness of MI Paste Plus and PreviDent fluoride varnish for treatment of white spot lesions: A randomized controlled trial. Am J Orthod Dentofacial Orthop. 2013 Jan;143(1):31-41. doi: 10.1016/j.ajodo.2012.09.007. PubMed PMID: 23273358.

The Dental Elf  9th Nov 2011 – MI Paste Plus helped prevent the development of new white spot lesions during orthodontic treatment


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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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