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. 2013 Aug 14;9:21. doi: 10.1186/1746-160X-9-21

Table 4.

Distribution of the root length reduction during orthodontic treatment of the individual teeth (upper and lower incisors, canines, first molars) (each n = 100, overall n = 1600): post-treatment RCR relative to pre-treatment RCR (rRCR), absolute (n) and relative (%) frequencies

  Tooth
rRCR
 16
 13
 12
 11
 21
 22
 23
 26
 46
 43
 42
 41
 31
 32
 33
 36
rRCR < 80
 7
 12
 6
 10
 7
 2
 7
 8
 1
 2
 1
 10
 14
 5
 6
 3
7.0
 12.0
 6.0
 10.0
 7.0
 2.0
 7.0
 8.0
 1.0
 2.0
 1.0
 10.0
 14.0
 5.0
 6.0
 3.0
80 ≤ rRCR < 90
 11
 11
 15
 11
 12
 11
 16
 8
 9
 9
 18
 15
 12
 11
 7
 14
11.0
 11.0
 15.0
 11.0
 12.0
 11.0
 16.0
 8.0
 9.0
 9.0
 18.0
 15.0
 12.0
 11.0
 7.0
 14.0
90 ≤ rRCR < 100
 22
 24
 28
 22
 22
 29
 27
 36
 38
 31
 25
 27
 25
 32
 24
 33
22.0
 24.0
 28.0
 22.0
 22.0
 29.0
 27.0
 36.0
 38.0
 31.0
 25.0
 27.0
 25.0
 32.0
 24.0
 33.0
rRCR ≥ 100
 60
 53
 51
 57
 59
 58
 50
 48
 52
 58
 56
 48
 49
 52
 63
 50
60.0
 53.0
 51.0
 57.0
 59.0
 58.0
 50.0
 48.0
 52.0
 58.0
 56.0
 48.0
 49.0
 52.0
 63.0
 50.0
Total (n) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100