Table 2 Mean changes in root length at baseline and 18-month follow-up

Mesial root (mm)

Baseline

Mean ± SD

11.01 ± 0.96

11.08 ± 1.18

0.880

Median

11.11

11.15

Interquartile range

10.32–11.76

10.23–12.17

18 months

Mean ± SD

12.82 ± 0.84

12.43 ± 0.97

0.496

Median

12.96

12.35

Interquartile range

11.95–13.52

10.66–13.33

Z

2.803

2.803

P

0.005*

0.005*

Root length mean difference

Mean ± SD

1.81 ± 0.45

1.34 ± 0.61

0.096

Median

1.81

1.56

Interquartile range

1.38–2.17

0.89–1.66

Distal root (mm)

Baseline

Mean ± SD

11.01 ± 0.87

11.02 ± 1.39

0.940

Median

11.15

11.19

Interquartile range

10.13–11.87

9.77–11.97

18 months

Mean ± SD

12.71 ± 0.76

12.42 ± 1.11

0.290

Median

12.63

12.28

Interquartile range

12.25–13.30

11.53–13.44

Z

2.803

2.803

P

0.005*

0.005*

Root length mean difference

Mean ± SD

1.71 ± 0.58

1.39 ± 0.65

0.174

Median

1.78

1.23

Interquartile range

1.25–2.02

0.90–1.70