M Beerens

82 CHAPTER 5 Participants Eligible subjects had been treated with orthodontic full fixed appliances in both arches at the Department of Orthodontics of ACTA. Subjects were enrolled after debonding and signing informed consent. All participants fulfilled the following requirements: 1) Healthy adolescent males or females between 12 and 19 years of age;, 2) Two or more buccal WSL on former bracketed surfaces, seen without prolonged air drying as a distinct visual change in enamel and/or localized enamel breakdown without clinical visual signs of dentinal involvement [International Caries Detection and Assessment System (ICDAS) code 2]; 3) No systemic diseases or syndromic abnormalities and 4) No proven or suspected milk protein allergy and/or sensitivity, or allergy to benzoate preservatives, as both are components of the MI Paste Plus ® product. Eligible subjects were invited to participate in this study and were screened by M.W.B. for WSL directly after debonding. The study group consisted of 65 participants: 28 male and 37 female subjects with a mean age of 15.5 years (SD = 1.6). Study settings This single center trial took place at the Department of Orthodontics, Academic Centre for Dentistry Amsterdam, The Netherlands from January 2008 to August 2010. Amsterdam is the capital of The Netherlands with a population of 756 000 at the time in 2009, having 156 000 children between the ages of 0 – 19 years (Centraal Bureau voor de Statistiek, 2009). There is a broad range in socioeconomic status for children undergoing orthodontic treatment, as orthodontics is mostly accessible for all children until the age of 18, as a result of the social health service structure. In Amsterdam, the community tap water is not fluoridated. Randomization, intervention procedure, and blinding Participants, complying with the inclusion criteria as determined by M.W.B., were randomly assigned by M.H.V. to group A (MI Paste Plus ® ) or B (the control group), as determined by a computer-randomization scheme, created and locked before the start of the study. Participant allocation was kept separate