Table 1 Comparison of mean and standard deviation values of working length estimated on CBCT and digital radiographic images in relation to the degree of canal curvature angles

Digital image

Overestimation

Closest to real length

Minimun to Maximun

N

20.86 ± 1.63

0.624 ± 0.409

0.2 to 2.3

43

20.43 ± 0.83

0.658 ± 0.293

0.3 to 1.2

17

20.72 ± 1.43

0.635 ± 0.374

0.2 to 2.3

60(100%)

0.27 **

0.75**

CBCT image

Overestimation

Closest to real length

Minimun to Maximun

N

19.43 ± 1.22

0.675 ± 0.892

0.1 to 2.0

4

20.3 ±

0.80 ±

− 0.8

1

19.6 ± 1.13

0.7 ± 0.775

0.1 to 2.0

5(8.3%)

0.47**

0.91**

Underestimation

Closest to real length

Minimun to Maximun

N

19.83 ± 1.72

− 0.494 ± 0.306

− 1.0 to − 0.1

36

19.41 ± 1.02

− 0.638 ± 0.280

− 1.2 to − 0.2

16

19.70 ± 1.54

− 0.538 ± 0.303

− 1.2 to − 0.1

52(86.7%)

0.81**

0.12**