M Beerens

68 CHAPTER 4 TABLE 3. Plaque ecology, determined by total bacterial counts, and the proportions of aciduric bacteria, Streptococcus mutans, and Lactobacillus spp., of samples from the casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACPF) group and the control group at three different time-points (T1,T2 and T3) Group CPP-ACPF Control T0 T2 T3  T0 T2 T3 Total counts (10 7 CFU per sample) 5.8 ± 4.1 4.1 ± 4.3 4.4 ± 6.0 3.3 ± 4.1 3.9 ± 4.3 5.2 ± 6.0 Aciduric bacteria (%) 52.5 ± 30.4 45.7 ± 28.4 * 44.7 ± 26.0 * 42.3 ± 30.4 41.6 ± 28.4 31.5 ± 26.0 * Streptococcus mutans (%) 9.4 ± 9.6 4.8 ± 5.9 * 9.0 ± 7.4 9.7 ± 9.6 4.9 ± 5.9 * 4.2 ± 7.4 * Lactobacillu s spp. (%) 0.2 ± 0.8 0.1 ± 1.1 0.1 ± 0.9 0.1 ± 0.8 0.4 ± 1.1 * 0.2 ± 0.9 Data are given as mean ± SD. Bacterial counts are expressed as a percentage of the total counts per sample obtained at each time- point. *Data significantly different from T0. DISCUSSION The null hypothesis could not be rejected. The use of CPP-ACPF paste (MI Paste Plus ® ) in vivo , in addition to normal oral hygiene, does not have an effect on: 1. remineralisation of subsurface lesions, and/or 2. plaque composition, expressed as the percentages of aciduric bacteria, S mutans , and Lactobacillus spp. in orthodontic patients with WSL after the removal of fixed orthodontic appliances. This contradicts the findings reported by Bailey et al . (Bailey et al. , 2009), but supports the findings of Bröchner et al . (Bröchner et al. , 2011) who studied the effects of a remineralisation cream containing CPP-ACP in the enhanced regression of postorthodontic WSL and the effect on plaque composition. Twelve weeks after debonding, the lesions showed significant improvement with respect to fluorescence loss, as monitored by QLF. Nevertheless, lesion regression after debonding was not seen to the extent expected. The time span of this study (12 weeks) may be too short to detect active lesion regression. Bröchner. (Bröchner et al. , 2011) reported a reduction in lesion area of 58% after only 4 weeks. However, the lesions investigated by Bröchner et al . (Bröchner et al. , 2011) were extremely small (0.19 mm 2 ) in comparison to the lesions studied in our study, which were (0.79 mm 2 ) at baseline. The fact