M Beerens

96 CHAPTER 5 S. mutans spp., Lactobacillus spp., and C. albicans , showed no change to a more healthier composition, observed for both groups. MI Paste Plus ® did not have an effect on the visual changes of WSL on the long term, when assessed on photographs. Lesions remained visible over time. DISCUSSION Key findings This study is the first to address the efficacy of MMP for the treatment of post-orthodontic WSL in vivo during 1 year following debonding. A lack of positive evidence was found to support the effectiveness of MI Paste Plus ® as a remineralising agent, to be effective for the treatment of post-orthodontic WSL. This outcome was confirmed by several independent detection methods, which strengthens this conclusion. Explanation MI Paste Plus ® does not have a positive effect on WSL improvement seen by QLF imaging or optical assessment nor does it have a neutralizing effect on the bacterial oral flora. Regardless of the application of the product or control, lesions tended to improve after removing orthodontic fixed appliance. Similarly, removing the orthodontic fixed appliance had a positive effect on the composition and acidity of the bacteria on the long term, which was not affected by either product. Comparing these findings with other studies Although the efficacy of CPP-ACPF for the prevention and regressionof incipient lesions has been demonstrated in vitro (Cochrane et al. , 2008; Reynolds et al. , 2008), there is a lack of reliable evidence for the treatment of post-orthodontic WSL in vivo (Chen et al. , 2013; Raphael and Blinkhorn, 2015) and the long-term effect of this remineralising agent is unclear (Li et al. , 2014). This study is the first to address these aspects. In vitro (Reynolds, 1997; Cochrane et al. , 2008) and in situ studies (Cai et al. , 2003; Morgan et al. , 2008; Reynolds et al. , 2008) have demonstrated that CPP-ACP may promote the remineralisation of subsurface enamel lesions. These findings are summarized in a meta-analysis for in vitro and in situ studies regarding the effect of CPP-ACP as a caries-preventive agent