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

	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

1 One way ANOVA with Bonferoni correction and chi-square tests were performed.

1 Sd, standard deviation.

A, Bone thickness measurement in the infrazygomatic crest at the apex of the root at 70° angulation. B, Total bucco-lingual bone thickness measurement in the mandibular buccal shelf. Two different horizontal reference lines positioned apically at 6 mm and 11 mm from the cemento-enamel junction were used. Total thickness at 6 mm; bucco-lingual thicknesses of bone on a horizontal reference line positioned apically at 6 mm from the cemento-enamel junction, Total thickness at 11 mm; total bucco-lingual thicknesses of bone on horizontal reference lines positioned apically at 11 mm from the cemento-enamel junction. C, Total inciso-apical bone height measurement in the mandibular buccal shelf. Two different vertical reference lines buccally positioned at 4 mm and 6 mm from the cemento-enamel junction, were used. Total height at 4 mm; total inciso-apical height thicknesses of bone on vertical reference line buccally positioned at 4 mm from the cemento-enamel junction, Total height at 6 mm; total inciso-apical height thicknesses of bone on a vertical reference line buccally positioned at 6 mm from the cemento-enamel junction.

Bone density measurements (mean value of Hounsfield units-HU) from outside the 2 mm isometric voxel.

Table II.

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

1 One Way ANOVA test with Bonferroni correction was performed.

1 HU value, mean value of Hounsfield Unit; IZC, infrazygomatic crest; L, left side; MBS, mandibular buccal shelf area; M1mr, first molar’s mesial root, M1dr, first molar’s distal root, M2mr, second molar’s mesial root; M2dr, second molar’s distal root; NS, nonsignificant; R, right side; Sd, standard deviation.

Table III.

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

1 One way ANOVA test with Bonferroni correction was performed.

1 IZC, infrazygomatic crest; MBS, mandibular buccal shelf area; M1mr, first molar’s mesial root; M1dr, first molar’s distal root; M2mr, second molar’s mesial root; M2dr, second molar’s distal root; NS, nonsignificant; Sd, standard deviation.

Table IV.

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

1 Pearson’s correlation test was performed.

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DOI: https://doi.org/10.2478/aoj-2024-0002 | Journal eISSN: 2207-7480 | Journal ISSN: 2207-7472

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Language: English

Page range: 1 - 12

Submitted on: Sep 1, 2023

Accepted on: Jan 1, 2024

Published on: Feb 19, 2024

Published by: Australian Society of Orthodontists Inc.

In partnership with: Paradigm Publishing Services

Publication frequency: 1 issue per year

Related subjects:

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© 2024 Elif Dilara Seker, Elif Kaymakcioglu, Serife Sahin, Gokmen Kurt, published by Australian Society of Orthodontists Inc.
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 40 (2024): Issue 1 (January 2024)

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

Figures & Tables

Table I.

Figure 1.

Figure 2.

Table II.

Table III.

Table IV.

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