Evaluation of the infrazygomatic crest and mandibular buccal shelf in different sagittal skeletal patterns: a cone-beam computed tomography study

Figure 1.

Figure 2.

Demographic data of the patients

	Class II	Class I	Class III			post-hoc p-value
Variables	mean ± sd	mean ± sd	mean ± sd	p-value	I-II	II-III	I-III
Age	30.08 ± 5.9	26.46 ± 6.1	26.21 ± 5.3	0.18
			Sex
Female	28 (90.3 %)	24 (85.7 %)	22 (84.6 %)	0.63
Male	3 (9.6 %)	4 (14.2 %)	4 (15.3 %)
			Upper Third Molar
Present	20	18	16	0.72
Absent	11	10	10
			Lower Third Molar
Present	18	16	20	0.81
Absent	13	12	6
SNA°	82.7 ± 4.6	82.8 ± 5.6	79.3 ± 3.4	0.09
SNB°	75.8 ± 4.6	80.6 ± 5.9	83.3 ± 3.5	0.001	0.04	0.001	NS
ANB°	6.8 ± 2.4	2.1 ± 1.1	-4 ± 3.5	<0.001	<0.001	<0.001	<0.001
SN-GoMe°	35.2 ± 7.5	31.2 ± 4.4	32.5 ± 5.5	0.26

Comparison of the quantitative bone characteristics between different sites in IZC and MBS on right side for each group

	M1mr (I)	M1dr (II)	M2mr (III)	M2dr (IV)		post hoc pvalue
Class II	mean ± sd	mean ± sd	mean ± sd	mean ± sd	p-value	I-II	I-III	I-IV	II-III	II-IV	III-IV
					IZC (mm)
Total thickness at 70°	2.5 ± 1.5	2.6 ± 1.5	2.2 ± 1.3	2.4 ±1.5	0.85
					MBS (mm)
Total thickness at 6 mm	4.2 ± 3.2	5 ± 3.4	6.5 ± 2.2	7.5 ±2.3	<0.001	NS	0.04	0.001	NS	0.01	NS
Total thickness at 11 mm	5.2 ± 2.9	6.3 ± 3.1	7.2 ± 1.9	8 ±2.2	0.002	NS	0.04	0.002	NS	NS	NS
Total height at 4 mm	18.4 ±7.1	19.9 ± 6.5	22.7 ± 2.9	23.8 ±2.9	0.002	NS	0.03	0.003	NS	NS	NS
Total height at 6 mm	14.6 ±7.4	16.5 ± 6.4	20.4 ± 3.6	22.1 ±3.7	<0.001	NS	0.003	<0.001	NS	0.005	NS
					Class I
					IZC (mm)
Total thickness at 70°	3.5 ± 1.9	3.2 ± 1.7	3.3 ± 1.8	3.71 ±1.9	0.75
					MBS (mm)
Total thickness at 6 mm	2.6 ± 2	4 ± 3.1	5.8 ± 2.3	7.2 ±2.3	<0.001	NS	<0.001	<0.001	0.04	<0.001	NS
Total thickness at 11 mm	4.2 ± 2.6	6 ± 2.5	6.6 ± 2.4	7.4 ±2.4	<0.001	0.03	0.002	<0.001	NS	NS	NS
Total height at 4 mm	17.7 ±9.7	20 ± 7.7	19.8 ± 7.3	20.9 ±6.1	0.46
Total height at 6 mm	15.3 ±9.4	17.2 ± 8.5	17.6 ± 8.1	19 ±7.6	0.4
					Class III
					IZC (mm)
Total thickness at 70°	3 ± 2.1	2.9 ± 1.9	3 ± 1.5	3.3 ± 1.9	0.89
					MBS (mm)
Total thickness at 6 mm	2.8 ± 2	4.4 ± 2.4	7.1 ±1.9	8.5 ± 2	<0.001	0.03	<0.001	<0.001	<0.001	<0.001	NS
Total thickness at 11 mm	5 ± 2.6	6.7 ± 1.8	7.9 ± 1.6	8.6 ± 1.9	<0.001	0.01	<0.001	<0.001	NS	0.004	NS
Total height at 4 mm	17 ± 5.1	19.6 ±4	20.1 ± 3.1	20.4 ± 2.9	0.007	NS	0.02	0.01	NS	NS	NS
Total height at 6 mm	13.1 ± 6.7	17 ± 5.1	17.9 ± 3.9	19.7 ± 3.8	<0.001	0.02	0.003	<0.001	NS	NS	NS

Correlation between cephalometric parameters and quantitative bone characteristics

	SNA		SNB		Maxillary Length		Mandibular Length
	r	p-Value	r	p-Value	r	p-Value	r	p-Value
	M1mr
Total thickness at 70°	0.070	0.66	0.048	0.76	-0.186	0.24	0.238	0.13
Total thickness at 6 mm	0.202	0.2	-0.034	0.83	0.295	0.06	0.207	0.19
Total thickness at 11 mm	0.301	0.05	0.328	0.03	0.212	0.18	0.331	0.03
Total height at 4 mm	0.174	0.27	0.140	0.38	0.124	0.44	0.440	0.004
Total height at 6 mm	0.284	0.07	0.246	0.12	0.220	0.16	0.357	0.02
	M1dr
Total thickness at 70°	0.032	0.84	0.035	0.83	-0.120	0.45	0.267	0.09
Total thickness at 6 mm	0.131	0.41	0.031	0.84	0.164	0.3	0.268	0.09
Total thickness at 11 mm	0.293	0.06	0.346	0.02	0.030	0.85	0.375	0.01
Total height at 4 mm	0.028	0.86	0.059	0.71	0.018	0.90	0.504	0.001
Total height at 6 mm	0.139	0.38	0.211	0.18	0.087	0.58	0.450	0.003
	M2mr
Total thickness at 70°	-0.088	0.58	0.089	0.57	-0.001	0.99	0.210	0.08
Total thickness at 6 mm	0.189	0.23	0.358	0.02	-0.059	0.71	0.508	0.001
Total thickness at 11 mm	0.085	0.59	0.358	0.02	-0.023	0.88	0.346	0.02
Total height at 4 mm	0.059	0.71	-0.092	0.56	0.155	0.33	0.384	0.01
Total height at 6 mm	0.089	0.57	0.002	0.99	0.124	0.44	0.508	0.001
	M2dr
Total thickness at 70°	-0.190	0.23	-0.044	0.78	-0.069	0.66	0.233	0.14
Total thickness at 6 mm	0.042	0.79	0.355	0.02	-0.043	0.79	0.523	<0.001
Total thickness at 11 mm	0.150	0.34	0.281	0.07	0.051	0.73	0.431	0.005
Total height at 4 mm	0.035	0.82	-0.208	0.19	0.132	0.41	0.293	0.03
Total height at 6 mm	-0.012	0.94	-0.115	0.47	0.081	0.61	0.430	0.005

Comparison of the quantitative bone characteristics in IZC and MBS among Class I, II and III groups

		M1mr				M1dr				M2mr						M2dr
	Class II	Class I	Class III		Class II	Class I	Class III		Class II	Class I	Class III			post-hoc pvalue		Class II	Class I	Class III			post-hoc p-value
	mean ± sd	mean ± sd	mean ± sd	p-value	mean ± sd	mean ± sd	mean ± sd	p-value	mean ± sd	mean ± sd	mean ± sd	p-value	I-II	II-III	I-III	mean ± sd	mean ± sd	mean ± sd	p-value	I-II	II-III	I-III
IZC Thickness (rnrnļ
Total_thick at 70°	2.5 ± 1.5	3.5 ± 1.9	3 ± 2.1	NS	2.6 ± 1.5	3.2 ± 1.7	2.9 ± 1.9	NS	2.2 ± 1.3	3.3 ± 1.8	3 ± 1.5	0.04	0.04	NS	NS	2.4 ± 1.5	3.7 ± 1.9	3.3 ± 1.9	0.04	0.03 NS NS
MBS Thickness (mm)
Total thickness at 6 mm	4.2 ± 3.2	2.6 ± 2	2.8 ± 2	NS	5 ± 3.4	4 ± 3.1	4.4 ± 2.4	NS	6.5 ± 2.2	5.8 ± 2.3	7.1 ± 1.9	NS		7.5 ±2.3	7.2 ±2.3	8.5 ± 2	NS
Total thickness at 11 mm	5.2 ± 2.6	4.2 ± 2.6	5 ± 2.6	NS	6.3 ± 3.1	6 ± 2.5	6.7 ± 1.8	NS	7.2 ± 1.9	6.6 ± 2.4	7.9 ± l.6	NS		8 ±2.2	7.4 ±2.4	8.6 ± 1.9	NS
Total height at 4 mm	18.4 ± 7.1	17.7 ± 9.7	17 ± 5.1	NS	l9.9± 6.5	20 ± 7.7	19.6 ± 4	NS	22.7 ± 2.9	19.8 ±7.3	20.1 ± 3.1	NS		23.8 ± 2.9	20.9 ±6.l	20.4 ± 2.9	0.01	0.04	0.01	NS
Total height at 6 mm	14.6 ± 7.4	15.3 ± 9.4	13.1 ± 6.7	NS	16.5 ± 6.4	17.2 ± 8.5	17 ± 5.1	NS	20.4 ± 3.6	17.6 ± 8.1	17.9 ± 3.9	NS		22.1 ± 3.7	19 ± 7.6	19.7 ± 3.8	0.04	0.01	NS	NS
HU Value
	Class II	Class I	Class III
	mean ± sd	mean ± sd	mean ± sd	p-value
Maxilla	681.7± 221.3	676 ± 185.6	728 ± 127.8	NS
Mandible	1187.5 ± 400.6	902.2 ± 473.3	902.7 ± 294.5	NS