M Beerens

16 CHAPTER 1 AIM OF THE STUDY The main ingredient of MI Paste Plus ® , CPP-ACPF was shown to be effective in remineralizing WSL when tested in in vitro , animal, and human in situ caries models. Its effectiveness has been described for both primary prevention as well as for the regression of WSL in a controlled environment (Chen et al. , 2013). There is a lack of reliable evidence to support the effectiveness of CPP- ACPF present in the commercially available remineralisation MI Paste Plus ® product especially in post-orthodontic white spot lesions (Chen et al. , 2013; Li et al. , 2014). This thesis assesses the effectiveness of MI Paste Plus ® as a remineralisation agent in patients with existing WSL after fixed orthodontic appliance treatment. Therefore, a prospective, double-blind, randomized, placebo-controlled trial has been conducted and analysed. In Chapter 2, changes in white spot lesions in former orthodontic patients were assessed over a 12 months period by comparing two outcome measures: 1. scoring visual changes and ICDAS on clinical oral photographs, and 2. quantitative light-induced fluorescence imaging (QLF), aiming to assess discrimination accuracy in monitoring changes in lesion severity. In Chapter 3, dental plaque, in orthodontic patients who were scheduled for appliance removal, was assessed by two outcome measures: 1. Denaturing Gradient Gel Electrophoresis (DGGE), and 2. conventional microbiology, aiming to test the predictability of DGGE as a risk indicator for the development of WSL during orthodontic treatment. In Chapter 4, the effectiveness of MI Paste Plus ® as a remineralizing agent was analysed over time, for a period of 3 months, by assessing two outcome measures: 1. QLF imaging, and 2. conventional microbiology.