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The accuracy (trueness and precision) of Bellus3DARC-7 and an in-vivo analysis of intra and inter-examiner reliability of digital and manual anthropometry

Jenny Doan
Jenny Doan
, 
Nessa Finlay
Nessa Finlay
, 
Amy Lee
Amy Lee
, 
Thomas Ethell
Thomas Ethell
, 
Narayan Gandedkar
Narayan Gandedkar
 and 
Mehmet Ali Darendeliler
Mehmet Ali Darendeliler
   | May 18, 2023
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Published Online: May 18, 2023
Page range: 141 - 157
Received: Feb 01, 2023
Accepted: Apr 01, 2024
DOI: https://doi.org/10.2478/aoj-2023-0015
© 2023 Jenny Doan et al., published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1.

Nineteen landmarks marked on a facial map: 1, Reference Point (Ref); 2, Glabella; 3, Right Cheek (R Cheek); 4, Left Cheek (L Cheek); 5, Nasal Tip; 6, Subnasale; 7, Right Commissure (R Commissure); 8, Left Commissure (L Commissure); 9, Soft Tissue Pogonion; 10, Right Alar Base (R Alar Base); 11, Left Alar Base (L Alar Case); 12, Right Gonion (R Gonion); 13, Left Gonion (L Gonion); 14, Left Upper Ear (L Upper ear); 15, Left Tragus (L Tragus); 16, Left Lower Ear (L Lower Ear); 17, Right Upper Ear (R Upper Ear); 18, Right Tragus (R Tragus); 19, Right Lower Ear (R Lower Ear) (Table I).
Nineteen landmarks marked on a facial map: 1, Reference Point (Ref); 2, Glabella; 3, Right Cheek (R Cheek); 4, Left Cheek (L Cheek); 5, Nasal Tip; 6, Subnasale; 7, Right Commissure (R Commissure); 8, Left Commissure (L Commissure); 9, Soft Tissue Pogonion; 10, Right Alar Base (R Alar Base); 11, Left Alar Base (L Alar Case); 12, Right Gonion (R Gonion); 13, Left Gonion (L Gonion); 14, Left Upper Ear (L Upper ear); 15, Left Tragus (L Tragus); 16, Left Lower Ear (L Lower Ear); 17, Right Upper Ear (R Upper Ear); 18, Right Tragus (R Tragus); 19, Right Lower Ear (R Lower Ear) (Table I).

Figure 2.

Examples of 3D digital models captured by the Bellus3D ARC-7 camera. (A) Frontal View. (B) Angled View.
Examples of 3D digital models captured by the Bellus3D ARC-7 camera. (A) Frontal View. (B) Angled View.

Figure 3.

A facial Map outlining the reproducibility of pooled digital measurements taken by all examiners. (Legend: Mean Difference of repeated measurements depicted in Dark green = <0.5 mm, yellow = ≥1.0 mm. Grey=Not determinable).
A facial Map outlining the reproducibility of pooled digital measurements taken by all examiners. (Legend: Mean Difference of repeated measurements depicted in Dark green = <0.5 mm, yellow = ≥1.0 mm. Grey=Not determinable).

Figure 4.

A Facial Map outlining the reproducibility of pooled manual measurements taken by all examiners. (Legend: Mean Difference of repeated measurements depicted in Dark green = <0.5 mm, Light green = <1.0 mm, yellow = ≥1.0 mm).
A Facial Map outlining the reproducibility of pooled manual measurements taken by all examiners. (Legend: Mean Difference of repeated measurements depicted in Dark green = <0.5 mm, Light green = <1.0 mm, yellow = ≥1.0 mm).

Figure 5.

A Facial Map outlining the reproducibility of measurements taken on two consecutive digital models of the same sample. (Legend: Mean Difference of repeated measurements depicted in Dark green = <0.5 mm, Light green = <1.0 mm, yellow = ≥1.0 mm).
A Facial Map outlining the reproducibility of measurements taken on two consecutive digital models of the same sample. (Legend: Mean Difference of repeated measurements depicted in Dark green = <0.5 mm, Light green = <1.0 mm, yellow = ≥1.0 mm).

Figure 6.

A Facial Map outlining the deviation of digital measurements from manual measurements on models (at rest). (Legend: Mean Deviations depicted in Dark green = <0.5 mm, Light green = <1.0 mm, Yellow = ≤1.5 mm, Orange = ≤2.00 mm, Red = >2.00 mm).
A Facial Map outlining the deviation of digital measurements from manual measurements on models (at rest). (Legend: Mean Deviations depicted in Dark green = <0.5 mm, Light green = <1.0 mm, Yellow = ≤1.5 mm, Orange = ≤2.00 mm, Red = >2.00 mm).

Figure 7.

A Facial Map outlining the deviation of digital measurements from manual measurements on models (during smiling). (Legend: Mean Deviations depicted in Dark green = <0.5 mm, Light green = <1.0 mm, Yellow = ≤1.5 mm, Orange = ≤2.00 mm, Red = >2.00 mm).
A Facial Map outlining the deviation of digital measurements from manual measurements on models (during smiling). (Legend: Mean Deviations depicted in Dark green = <0.5 mm, Light green = <1.0 mm, Yellow = ≤1.5 mm, Orange = ≤2.00 mm, Red = >2.00 mm).

Figure 8.

Bell curve displays that the majority of digital vs calliper deviated measurements were within 2 mm.
Bell curve displays that the majority of digital vs calliper deviated measurements were within 2 mm.

Figure 9.

The variability of measurements between landmarks. Green: Measurements between these landmarks had the least variability within and between examiners, for both calliper and digital methods. Grey: Measurements between these landmarks also had the most variability when comparing calliper and digital methods.
The variability of measurements between landmarks. Green: Measurements between these landmarks had the least variability within and between examiners, for both calliper and digital methods. Grey: Measurements between these landmarks also had the most variability when comparing calliper and digital methods.

Figure 10.

Examples of distortion of stickers, digital landmarks and soft tissues. (A) Hairline (B) Ears concealed by hair. (C) Ear lobe. (D) Lips & teeth during smile. (E) Pogonion, with blurred sticker. (F) L Cheek, with double image.
Examples of distortion of stickers, digital landmarks and soft tissues. (A) Hairline (B) Ears concealed by hair. (C) Ear lobe. (D) Lips & teeth during smile. (E) Pogonion, with blurred sticker. (F) L Cheek, with double image.

Appendix 1.

Table containing raw data of difference between the digital and manual inter-landmark measurements (on models at rest).
Table containing raw data of difference between the digital and manual inter-landmark measurements (on models at rest).

Appendix 2.

Table containing raw data of difference between the digital and manual inter-landmark measurements (on models during smiling).
Table containing raw data of difference between the digital and manual inter-landmark measurements (on models during smiling).

Mean difference in measurements of inter-landmark measurements taken on two consecutive digital models of the same sample

Landmark 1 Landmark 2 Mean Difference (mm)
Ref Glabella 0.25
Glabella Nose Tip 0.19
Subnasale Pogonion 0.54
R Cheek L Cheek 0.46
R Alar L Alar 0.38
R Commissure L Commissure 0.87
R Upper Ear R Middle Ear N/A
R Middle Ear R Lower Ear 0.57
R Cheek R Gonion 0.53
R Cheek R Middle Ear 0.69
R Gonion R Commissure 0.51
L Upper Ear L Middle Ear 0.47
L Middle Ear L Lower Ear 0.37
L Cheek L Gonion 0.23
L Cheek L Middle Ear 0.27
L Gonion L Commissure 1.11
      Colour Legend: 0 - 0.5mm 0.5 - 1.0mm 1.0 - 1.5mm 1.5 - 2.0mm 2.0+mm

The mean difference in pooled digital measurements of inter-landmark measurements taken by all examiners

Landmark 1 Landmark 2 Mean difference (mm)
Ref Glabella 0.25
Glabella Nose Tip 0.19
Subnasale Pogonion 0.23
R Cheek L Cheek 0.11
R Alar L Alar 0.09
R Commissure L Commissure 0.31
R Upper Ear R Middle Ear N/A
R Middle Ear R Lower Ear 0.28
R Cheek R Gonion 0.33
R Cheek R Middle Ear 0.23
R Gonion R Commissure 0.29
L Upper Ear L Middle Ear 0.23
L Middle Ear L Lower Ear 0.41
L Cheek L Gonion 0.26
L Cheek L Middle Ear 0.32
L Gonion L Commissure 1.16
      Colour Legend: 0 to 0.5mm 0.5 to 1.0mm 1.0 to 1.5mm 1.5 to 2.0mm 2.0+mm

Landmarks and respective number as marked on facial map in Figure 1

Number Landmark
1 Reference Point
2 Glabella
3 R Cheek
4 L Cheek
5 Nasal Tip
6 Subnasale
7 R Commissure
8 L Commissure
9 Soft Tissue Pogonion
10 R Alar Base
11 L Alar Base
12 R Gonion
13 L Gonion
14 L Upper Ear
15 L Tragus
16 L Lower Ear
17 R Upper Ear
18 R Tragus
19 R Lower Ear

The mean difference in pooled manual measurements of inter-landmark measurements taken by all examiners

Landmark 1 Landmark 2 Mean Difference (mm)
Ref Glabella 0.35
Glabella Nose Tip 0.64
Subnasale Pogonion 0.90
R Cheek L Cheek 1.14
R Alar L Alar 0.65
R Commissure L Commissure 0.99
R Upper Ear R Middle Ear 0.70
R Middle Ear R Lower Ear 0.28
R Cheek R Gonion 1.28
R Cheek R Middle Ear 0.80
R Gonion R Commissure 0.69
L Upper Ear L Middle Ear 0.72
L Middle Ear L Lower Ear 0.47
L Cheek L Gonion 1.38
L Cheek L Middle Ear 0.62
L Gonion L Commissure 0.26
      Colour Legend: 0 to 0.5 mm 0.5 to 1.0 mm 1.0 to 1.5 mm 1.5 to 2.0 mm 2.0+mm

The overall proportion of combined manual measurements within set threshold deviation values, obtained by a single examiner

% of measurements within set threshold deviation of:
≤0.5 mm 88%
≤1.0 mm 98%
≤1.5 mm 100%
≤2.0 mm 100%

The mean difference between digital and manual inter-landmark measurements on models (during smiling)

Landmark 1 Landmark 2 Mean difference (mm)
Ref Glabella 0.39
L Upper Ear L Middle Ear 0.31
R Middle Ear R Lower Ear 0.46
Glabella Nose Tip 0.57
L Middle Ear L Lower Ear 0.66
R Cheek R Middle Ear 0.79
L Cheek L Middle Ear 0.95
R Cheek R Gonion 1.24
L Cheek L Gonion 1.33
R Alar L Alar 1.44
R Cheek L Cheek 1.68
L Gonion L Commissure 1.85
R Commissure L Commissure 1.88
Subnasale Pogonion 2.20
R Gonion R Commissure 2.28
R Upper Ear R Middle Ear N/A
      Colour Legend: 0 to 0.5mm 0.5 to 1.0mm 1.0 to 1.5mm 1.5 to 2.0mm 2.0+mm

The proportion of manual measurements within set threshold deviation values, obtained by a single examiner (categorised by interlandmark variables)

Inter-landmark measurements % of measurements within set threshold deviations of:
Landmark 1 Landmark 2 ≤0.5 mm ≤1.0 mm ≤1.5 mm ≤2.0 mm
Ref Glabella 75% 88% 100% 100%
Glabella Nose Tip 38% 75% 100% 100%
Subnasale Pogonion 50% 63% 75% 88%
R Cheek L Cheek 25% 50% 75% 88%
R Alar L Alar 25% 75% 100% 100%
R Commissure L Commissure 25% 75% 88% 88%
R Upper Ear R Middle Ear 38% 88% 88% 100%
R Middle Ear R Lower Ear 75% 100% 100% 100%
R Cheek R Gonion 13% 38% 50% 75%
R Cheek R Middle Ear 38% 75% 88% 88%
R Gonion R Commissure 38% 75% 88% 100%
L Upper Ear L Middle Ear 38% 75% 88% 100%
L Middle Ear L Lower Ear 63% 100% 100% 100%
L Cheek L Gonion 13% 50% 75% 75%
L Cheek L Middle Ear 50% 75% 88% 100%
L Gonion L Commissure 38% 50% 63% 88%

The mean difference between digital and manual inter-landmark measurements on models (at rest)

Landmark 1 Landmark 2 Mean difference (mm)
L Upper Ear L Middle Ear 0.27
R Middle Ear R Lower Ear 0.52
R Cheek R Middle Ear 0.56
Glabella Nose Tip 0.61
L Middle Ear L Lower Ear 0.61
Ref Glabella 0.71
L Cheek L Middle Ear 0.78
R Alar L Alar 0.94
R Cheek L Cheek 1.10
Subnasale Pogonion 1.11
R Gonion R Commissure 1.13
R Commissure L Commissure 1.52
L Cheek L Gonion 1.63
R Cheek R Gonion 1.76
L Gonion L Commissure 2.12
R Upper Ear R Middle Ear N/A
      Colour Legend: 0 to 0.5 mm 0.5 to 1.0 mm 1.0 to 1.5 mm 1.5 to 2.0 mm 2.0+mm

The proportion of digital measurements within set threshold deviation values, obtained by a single examiner (categorised by interlandmark variables)

Inter-landmark Variables % of measurements within set threshold deviations of:
Landmark 1 Landmark 2 ≤0.5 mm ≤1.0 mm ≤1.5 mm ≤2.0 mm
Ref Glabella 100% 100% 100% 100%
Glabella Nose Tip 88% 100% 100% 100%
Subnasale Pogonion 75% 100% 100% 100%
R Cheek L Cheek 100% 100% 100% 100%
R Alar L Alar 100% 100% 100% 100%
R Commissure L Commissure 75% 100% 100% 100%
R Upper Ear R Middle Ear N/A N/A N/A N/A
R Middle Ear R Lower Ear 88% 100% 100% 100%
R Cheek R Gonion 75% 100% 100% 100%
R Cheek R Middle Ear 100% 100% 100% 100%
R Gonion R Commissure 88% 88% 100% 100%
L Upper Ear L Middle Ear 100% 100% 100% 100%
L Middle Ear L Lower Ear 75% 88% 100% 100%
L Cheek L Gonion 88% 100% 100% 100%
L Cheek L Middle Ear 88% 100% 100% 100%
L Gonion L Commissure 75% 100% 100% 100%
eISSN:
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