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Figure 1.
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.
Figure 2.
Bone density measurements (mean value of Hounsfield units-HU) from outside the 2 mm isometric voxel.
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