From: Frequency evaluation of different extraction protocols in orthodontic treatment during 35 years
Interval | Protocol | Total | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | N | % | |||||||||||
Non-extraction | Four first premolar extractions | Two maxillary first and two mandibular second premolar extractions | Two maxillary premolar extractions | Four second premolar extractions | Asymmetric extractions - three premolars or only one premolar | Incisor or canine extractions | First or second molar extractions | Atypical extractions | Agenesis or previously missing permanent teeth | |||||||||||||
N | % | N | % | N | % | N | % | N | % | N | % | N | % | N | % | N | % | N | % | |||
1 | 15 | A | 57 | A | 11 | ABC | 6 | BC | 1 | BC | 1 | ABC | 0 | 0 | 0 | 0 | 2 | 1.90 | 12 | 11.43 | 105 | 3.08 |
(1973 to 1977) | 14.29 | 54.29 | 10.48 | 5.71 | 0.95 | 0.95 | ||||||||||||||||
2 | 28 | AB | 84 | A | 5 | CD | 5 | AB | 2 | BC | 1 | AB | 0 | 0 | 0 | 0 | 2 | 1.37 | 19 | 13.01 | 146 | 4.28 |
(1978 to 1982) | 19.18 | 57.53 | 3.42 | 3.42 | 1.37 | 0.68 | ||||||||||||||||
3 | 91 | B | 90 | B | 40 | A | 34 | BC | 11 | CD | 4 | A | 1 | 0.32 | 3 | 0.96 | 14 | 4.46 | 26 | 8.28 | 314 | 9.20 |
(1983 to 1987) | 28.98 | 28.66 | 12.74 | 10.83 | 3.50 | 1.27 | ||||||||||||||||
4 | 273 | CD | 170 | B | 34 | BC | 62 | BC | 7 | BC | 13 | A | 2 | 0.30 | 7 | 1.05 | 23 | 3.45 | 75 | 11.26 | 666 | 19.51 |
(1988 to 1992) | 40.99 | 25.53 | 5.11 | 9.31 | 1.05 | 1.95 | ||||||||||||||||
5 | 491 | C | 281 | B | 63 | BC | 137 | CD | 13 | BC | 61 | BC | 6 | 0.48 | 10 | 0.79 | 61 | 4.83 | 139 | 11.01 | 1262 | 36.98 |
(1993 to 1997) | 38.91 | 22.27 | 4.99 | 10.8 | 1.03 | 4.83 | ||||||||||||||||
6 | 290 | DE | 95 | C | 25 | BCD | 67 | CD | 2 | AB | 44 | C | 1 | 0.16 | 6 | 0.98 | 19 | 3.10 | 63 | 10.29 | 612 | 17.93 |
(1998 to 2002) | 47.39 | 15.52 | 4.08 | 10.95 | 0.33 | 7.19 | ||||||||||||||||
7 | 168 | E | 23 | D | 4 | D | 23 | BC | 6 | BC | 21 | C | 0 | 0 | 2 | 0.65 | 10 | 3.25 | 51 | 16.56 | 308 | 9.02 |
(2003 to 2007) | 54.55 | 7.47 | 1.30 | 7.47 | 1.95 | 6.82 | ||||||||||||||||
Total | 1,356 | 39.73 | 800 | 23.43 | 182 | 5.3 | 334 | 9.78 | 42 | 1.23 | 145 | 4.24 | 10 | 0.29 | 28 | 0.82 | 131 | 3.83 | 385 | 11.28 | 3,413 | 100 |
χ | 113.305 | 222.758 | 52.847 | 13.668 | 19.443 | 41.901 | 3.440 | 2.897 | 8.640 | 12.522 | ||||||||||||
P | 0.0000* | 0.0000* | 0.0000* | 0.0335* | 0.0034* | 0.0000* | 0.7518 | 0.8215 | 0.1948 | 0.0512 |