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Validity and reproducibility of a tripoding method in point registration-based 3D superimposition software compared to a conventional cephalometric method

Nor Nadia Zakaria
Nor Nadia Zakaria
, 
Wan Nurazreena Wan Hassan
Wan Nurazreena Wan Hassan
 and 
Yasmin Kamarudin
Yasmin Kamarudin
   | Sep 06, 2022
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Published Online: Sep 06, 2022
Page range: 281 - 289
Received: Feb 01, 2022
Accepted: Jul 01, 2022
DOI: https://doi.org/10.2478/aoj-2022-0030
© 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.
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).
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).
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).
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.
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
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