Table 1.

Root resorption measurements of upper teeth at T2 compared to T1

Upper teeth	Mean T1 (mm)	Mean T2 (mm)	Mean T1 – T2 (mm)	Standard deviation
Right 1st palatal molar	19.62	19.16	0.46	0.97
Mesiobuccal root	18.62	18.20	0.42	0.94
Distobuccal root	17.02	16.87	0.15	0.64
Right 2nd buccal premolar	20.35	20.1	0.25	0.87
Palatal root	20.08	20.70	−0.62	1.75
Right 1st buccal premolar	20.09	19.86	0.23	1.66
Palatal	19.07	19.70	−0.63	2.87
Right canine root	26.69	24.66	−2.03	0.99
Right lateral root	22.20	21.50	0.70	1.25
Right central root	22.74	22.01	0.74	1.26
Left central root	23.12	22.74	0.38	0.97
Left lateral root	22.70	21.95	0.75	1.30
Left canine	24.85	25.71	−0.75	1.25
Left 1st buccal premolar	19.84	19.85	−0.01	1.16
Palatal	19.81	19.20	0.60	2.40
Left 2nd buccal premolar	21.04	20.85	0.19	0.68
Palatal	20.82	20.87	−0.05	0.50
Left 1st palatal molar	19.61	19.38	0.23	0.90
Mesiobuccal	18.70	18.09	0.61	0.76
Distobuccal	17.27	16.96	0.30	1.26

Notes: Mean tooth length was measured first before the orthodontic treatment (T1) then at the end of the alignment and levelling process (T2). The mean root resorption was calculated as T1 – T2 for teeth in the maxilla.