pISSN 2234-7518
eISSN 2005-372X

Table. 4.

Comparison of the torques between the post-use and post-retention removal groups and between the placement sites or placement methods (unit, N cm)

Variable Post-use removal Post-retention removal p-value
(placement torque)
p-value
(removal torque)
Placement
torque
Removal
torque
n Placement
torque
Removal
torque
n
Total 8.06 ± 4.80 3.80 ± 2.34 399 6.17 ± 3.38 4.66 ± 2.15 169 0.000*** 0.000***
Placement site
Maxilla 7.34 ± 4.72 3.46 ± 1.93 213 5.61 ± 2.99 4.41 ± 2.05 130 0.000*** 0.000***
Mandible 8.88 ± 4.78 4.19 ± 2.68 186 8.04 ± 3.94 5.51 ± 2.27 39 0.306 0.005*
p-value (placement site) 0.001* 0.002* 0.000*** 0.005*
Placement method
No-drilling 7.08 ± 4.07 3.42 ± 1.83 266 5.50 ± 2.91 4.42 ± 2.04 125 0.000*** 0.000***
Pre-drilling 10.00 ± 5.53 4.55 ± 2.99 133 8.06 ± 3.90 5.36 ± 2.33 44 0.012* 0.102
p-value (placement method) 0.000*** 0.000*** 0.000*** 0.011*

Values are presented as mean ± standard deviation.

Independent t-test was performed for comparison between the post-use and post-retention removal groups, between the maxilla and mandible, and between the no-drilling and pre-drilling methods.

*p < 0.05; ***p < 0.001.

Korean J Orthod 2022;52:201~209 https://doi.org/10.4041/kjod21.217
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