Table 3 Measurement results of the mesial and distal minimum canal wall thickness pre- and post-instrumentation at the furcation levels (mm) (n = 6 per group)

1 mm

below FL

(Distal)

OS

1.25 ± 0.06

1.15 ± 0.09

1.22 ± 0.14

1.08 ± 0.08^b

0.83 ± 0.06^b

0.90 ± 0.11^b

TF

1.22 ± 0.05

1.12 ± 0.06

1.17 ± 0.08

1.04 ± 0.06^ab

0.84 ± 0.05^b

0.88 ± 0.07^b

PTG

1.25 ± 0.05

1.11 ± 0.05

1.20 ± 0.07

0.94 ± 0.10^a

0.75 ± 0.05^a

0.77 ± 0.05^a

F value

0.449

0.625

0.454

4.324

6.337

4.394

p value

0.647

0.549

0.644

0.033

0.010

0.032

1 mm

below FL

(Mesial)

OS

1.22 ± 0.11

1.39 ± 0.06^*

1.22 ± 0.05

1.17 ± 0.12^b

1.26 ± 0.02^b*

1.13 ± 0.07^b*

TF

1.24 ± 0.06

1.34 ± 0.05^*

1.22 ± 0.07

1.13 ± 0.07^b

1.23 ± 0.07^b*

1.08 ± 0.08^ab*

PTG

1.21 ± 0.04

1.30 ± 0.09^*

1.22 ± 0.05

0.96 ± 0.04^a

1.14 ± 0.05^a*

1.02 ± 0.04^a*

F value

0.203

2.690

0.025

11.52

10.95

4.110

p value

0.819

0.100

0.975

0.000

0.001

0.038

2 mm

below FL

(Distal)

OS

1.15 ± 0.09

1.05 ± 0.10

1.01 ± 0.09

1.01 ± 0.09^b

0.83 ± 0.09

0.76 ± 0.08^b

TF

1.11 ± 0.09

1.04 ± 0.08

0.99 ± 0.08

0.96 ± 0.10^b

0.83 ± 0.07

0.82 ± 0.06^b

PTG

1.08 ± 0.07

1.06 ± 0.03

0.91 ± 0.07

0.81 ± 0.03^a

0.74 ± 0.04

0.59 ± 0.06^a

F value

1.019

0.105

2.894

18.04

3.505

19.29

p value

0.385

0.901

0.087

0.000

0.056

0.000

2 mm

below FL

(Mesial)

OS

1.09 ± 0.08

1.21 ± 0.04^*

1.03 ± 0.05

0.99 ± 0.08^a

1.06 ± 0.07^b*

0.85 ± 0.03^b

TF

1.08 ± 0.11

1.19 ± 0.05^*

1.01 ± 0.04

0.92 ± 0.08^ab

1.03 ± 0.05^b*

0.83 ± 0.04^ab

PTG

1.08 ± 0.04

1.18 ± 0.03^*

0.99 ± 0.05

0.83 ± 0.04^a

0.93 ± 0.03^a*

0.77 ± 0.06 ^a*

F value

0.028

0.854

1.917

8.458

10.19

5.737

p value

0.972

0.447

0.181

0.004

0.002

0.014

3 mm

below FL

(Distal)

OS

1.11 ± 0.08

0.94 ± 0.07

0.89 ± 0.07

0.97 ± 0.10^b

0.80 ± 0.05^b

0.75 ± 0.09^ab

TF

1.10 ± 0.04

0.92 ± 0.07

0.85 ± 0.09

0.96 ± 0.05^b

0.79 ± 0.07^b

0.79 ± 0.08^b

PTG

1.12 ± 0.07

0.90 ± 0.04

0.86 ± 0.05

0.84 ± 0.08^a

0.69 ± 0.05^a

0.65 ± 0.05^a

F value

0.115

1.645

0.876

5.042

10.33

5.626

p value

0.893

0.226

0.437

0.021

0.002

0.015

3 mm

below FL

(Mesial)

OS

0.88 ± 0.09^*

1.02 ± 0.04

0.84 ± 0.09

0.79 ± 0.10^b*

0.82 ± 0.05^b

0.67 ± 0.07^b*

TF

0.89 ± 0.06^*

1.02 ± 0.04

0.84 ± 0.06

0.74 ± 0.03^ab*

0.83 ± 0.04^b

0.67 ± 0.03^b*

PTG

0.93 ± 0.07^*

1.02 ± 0.07

0.83 ± 0.07

0.66 ± 0.05^a*

0.72 ± 0.07^a

0.57 ± 0.07^a

F value

0.861

0.012

0.145

5.699

7.654

5.275

p value

0.443

0.988

0.486

0.014

0.005

0.018