Validity and reproducibility of a tripoding method in point registration-based 3D superimposition software compared to a conventional cephalometric method Publié en ligne: 06 sept. 2022 Pages: 281 - 289 Reçu: 01 févr. 2022 Accepté: 01 juil. 2022 © 2022 Nor Nadia Zakaria et al., published by Sciendo This work is licensed under the Creative Commons Attribution 4.0 International License.
Figure 1. Superimposition of the 3D study casts from lateral (above) and palatal (below) views. (a) Casts that were aligned using points on the anterior segment only, which comprised the medial two-third of the third palatal rugae, showed inconsistencies in the superimposition due to lack of pitch control. (b) Alignment of the casts using the tripoding method showed more consistent superimposition. Figure 2. Point registration-based software. Identification of 6 landmarks on the medial two-third of the third palatal rugae of both pre-treatment (top) and post-treatment cast (bottom). Figure 3. The superimposition area. (a) The anterior reference points (shaded area). (b) The posterior reference points (two arrows). Figure 4. Pancherz analysis landmarks and reference line: is, incisal tip of the most prominent maxillary central incisor; ms, mesial contact point of the maxillary permanent first molar determined by a tangent perpendicular to OL; sp, spinal point of the maxilla jaw base, OL, a line through is and the distobuccal cusp maxillary first permanent molar; OLp, is a line perpendicular to OL through s(sella); NL, nasal line or maxillary plane. SO analysis reference (a): position of the maxillary jaw base (sp/OLp), position of the most prominent central incisor (is/OLp) and position of the left permanent first molar (ms/OLp). VO analysis reference (b): position of the maxillary central incisor to the maxillary plane, (is/NL) and position of the permanent first molar cusp to the nasal line, (msc/NL). Figure 5. Bland-Altman plots for horizontal and vertical distance of the central incisor and first molar using two methods. Data analysis for incisor and molar movements measured from 3D models and cephalometric radiographs, each on two separate occasions (in mm).
Intraclass correlation (ICC)
Paired t test
Tooth movement
Measurement method
95% CI
ICC
p -value
Mean (SD)
Standard Error mean
95% CI of difference
t -stat (df)
p -value
Incisor Horizontal
3D
(0.88, 0.97)
0.94
<0.001
0.02 (0.65)
0.11
(-0.23,0.26)
0.13 (29)
0.90
Ceph
(0.67, 0.91)
0.83
<0.001
0.01 (1.50)
0.27
(-0.55,0.57)
0.05 (29)
0.96
Incisor Vertical
3D
(0.89, 0.97)
0.95
<0.001
-0.06 (0.48)
0.09
(-0.24,0.12)
-0.68 (29)
0.50
Ceph
(0.69, 0.92)
0.84
<0.001
0.23 (0.93)
0.17
(-0.12,0.58)
1.33 (29)
0.19
Molar Horizontal
3D
(0.89, 0.97)
0.94
<0.001
0.13 (0.46)
0.08
(-0.04,0.30)
1.56 (29)
0.13
Ceph
(0.63, 0.90)
0.81
<0.001
0.18 (1.18)
0.21
(-0.26,0.62)
0.82 (29)
0.42
Molar Vertical
3D
(0.86, 0.97)
0.93
<0.001
-0.03 (0.33)
0.60
(-0.16,0.09)
-0.56 (29)
0.58
Ceph
(0.76, 0.94)
0.88
<0.001
-0.05 (0.87)
0.16
(-0.37,0.28)
-0.31 (29)
0.76
Bland-Altman analysis and paired t tests comparing horizontal and vertical tooth movement from 3D and cephalometric superimpositions.
Paired t test
Bland–Altman
Tooth movement
Mean (SD)
Standard Error mean
95% CI of difference
t (df)
p -value
Mean difference (SD)
Lower Limit
Upper limit
Incisor horizontal
3D Ceph
0.41 (1.30)
0.24
(-0.07,0.89)
1.72 (29)
0.096
0.41 (1.30)
-2.14
2.95
Incisor vertical
3D Ceph
-0.51 (1.90)
0.35
(-1.21,0.20)
-1.46 (29)
0.156
-0.51 (1.90)
-4.23
3.22
Molar horizontal
3D Ceph
0.10 (1.54)
0.28
(-0.47,0.68)
0.37 (29)
0.712
0.10 (1.54)
-2.91
3.13
Molar vertical
3D Ceph
0.03 (1.35)
0.25
(-0.48,0.53)
0.11 (29)
0.916
0.03 (1.35)
-2.62
2.67