Frequency evaluation of different extraction protocols in orthodontic treatment during 35 years

Janson, Guilherme; Maria, Fábio Rogério Torres; Bombonatti, Roberto

doi:10.1186/s40510-014-0051-z

Progress in Orthodontics

Table 1 Frequency of 10 treatment protocols in all evaluated intervals (proportion test)

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)	15	14.29	57	54.29	11	10.48	6	5.71	1	0.95	1	0.95	0	0	0	0	2	1.90	12	11.43	105	3.08
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)	28	19.18	84	57.53	5	3.42	5	3.42	2	1.37	1	0.68	0	0	0	0	2	1.37	19	13.01	146	4.28
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)	91	28.98	90	28.66	40	12.74	34	10.83	11	3.50	4	1.27	1	0.32	3	0.96	14	4.46	26	8.28	314	9.20
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)	273	40.99	170	25.53	34	5.11	62	9.31	7	1.05	13	1.95	2	0.30	7	1.05	23	3.45	75	11.26	666	19.51
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)	491	38.91	281	22.27	63	4.99	137	10.8	13	1.03	61	4.83	6	0.48	10	0.79	61	4.83	139	11.01	1262	36.98
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)	290	47.39	95	15.52	25	4.08	67	10.95	2	0.33	44	7.19	1	0.16	6	0.98	19	3.10	63	10.29	612	17.93
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)	168	54.55	23	7.47	4	1.30	23	7.47	6	1.95	21	6.82	0	0	2	0.65	10	3.25	51	16.56	308	9.02
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

Different letters represent statistically significant differences in same protocol. *Statistically significant at P < 0.05.

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