M Beerens

66 CHAPTER 4 TABLE 1. Variables investigated in this study, overall (total), and separately in the casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACPF) and control groups Variable investigated CPP-ACPF group Control group Total (n = 27) (n = 27) (n = 54) Surfaces monitored 511 491 1002 Surfaces affected 211 213 424 Gender ratio (male : female) 1:1.25 1:1.45 1:1.35 Age at investigation (years/months) 15.2 ± 1.6 15.8 ± 1.3 15.5 ± 1.5 Duration of fixed appliance treatment (years/months) 2.6 ± 0.8 2.6 ± 0.00 2.5 ± 0.8 Data are given as n or as mean ± SD QLF results The intra-examiner agreement for M.W.B. was high with an ICC of 0.93. The inter-examiner agreement for the experienced examiner M.H.V. had an ICC of 0.87. Descriptive data for lesion depths [∆F (%), lesion area [A (mm 2 )], and IFL [IFL (% mm 2 )], measured at the three different time-points, T1, T2, and T3, within groups are shown in Table 2. Baseline data at T1 showed no significant differences between groups for DF, A, and IFL (P > 0.05). The significant improvement in lesion depth (DF) observed over time in both groups (P = 0.0004) was compared by repeated-measures ANOVA, but no significant difference was found between the groups. The Bonferroni post-hoc test identified a significant decrease in fluorescence loss (DF) from baseline to T3 with for both groups (P < 0.05) and no difference between groups. The lesion area (A) did not change significantly over time or between the groups. While the lesion area in the CPP-ACPF group remained essentially unchanged, the lesion area in the control group showed an initial decrease from T1 to T2, and then returned to the original value found at T1. The IFL did not change significantly over time and between the groups. In the CPP-ACPF group, the IFL was essentially unchanged over the time period studied, and in the control group some initial improvement was seen; however, three-quarters of the improvement was lost at T3.