Minimum Maximum Mean SD
Age (years) 11 51 20 10.52
ERR T2 (%) 0.0 10.7 2.1 2.38
ERR T3 (%) 0.0 12.1 3.5 3.03
Table 1: Descriptive statistics of the sample (n=47) in relation to age and ERR (%) after six (T2) and 12 (T3) months of treatment on 91 upper central incisors.