M Beerens

60 CHAPTER 4 The subjects fulfilled the following requirements: 1. healthy adolescent male and female subjects between 12 and 19 years of age, 2. two or more bracketed surfaces with buccal subsurface WSL, seen without prolonged air drying as a distinct visual change in enamel and/or localized enamel breakdown without clinical visual signs of dentinal involvement (Topping et al. , 2009), 3. no systemic diseases, 4. no syndromatic abnormalities, and 5. no proven or suspected milk protein allergy and/or sensitivity, or allergy to benzoate preservatives, as both are components of the CPP-ACPF product. Subjects were only enrolled after signed informed consent was obtained from the patient, and, in case of minors, also the parents/guardians. None of the subjects lived in an area where the community water was fluoridated. The study group consisted of 54 participants (23 male and 31 female subjects) with a mean age of 15.5 years. Study outline Subjects, complying with the inclusion criteria determined by M.W.B., were then randomly assigned by M.H.V. to either the CPP-ACPF group or the control group, as determined by a computer-randomization scheme that was created and locked before the start of the study. The subjects received neutral-coloured toothpaste tubes marked A or B, which contained either CPP-ACP + sodium fluoride (0.2% w/w; 900 p.p.m.) (MI Paste Plus® 35 ml, Recaldent; GC Benelux Europe, Leuven, Belgium) or fluoride-free control paste + calcium (Ultradent 100 ml; Kruidvat NL, Renswoude, the Netherlands) for home use. Subjects were informed that they could receive either a CPP-ACPF paste or a control paste with a different form of calcium delivery. Just before debonding (T0), the subjects were screened for the presence of WSL by means of visual inspection and by use of QLF imaging. Plaque was collected buccally from the lower right first premolars at screening and 6 (T2) and 12 (T3) weeks after the start of the intervention. Immediately after debonding (T1), QLF baseline images were captured as described below. Follow-up QLF images were captured 6 (T2) and 12 (T3) weeks after debonding.