Three-dimensional evaluation of orofacial movements during articulation in patients with skeletal Class III malocclusion with mandibular asymmetry

Figures & data

Table 1. The inclusion and exclusion criteria of this study.

Criteria	AFD	SFD	CTRL
Inclusion criteria
General criteria	Native Japanese speakers
	More than 16 years old
Individual criteria	M: ANB < 0.62 F: ANB < 1.62	M: ANB < 0.62 F: ANB < 1.62	M: 0.62° < ANB < 5.94° F: 1.62° < ANB < 5.16°
	Menton deviation >4mm	Menton deviation < 4mm	Menton deviation < 4mm
	Planned for orthognathic surgery	Planned for orthognathic surgery	Planned for orthodontic treatment without surgery
Exclusion criteria
	Morphological or functional problems
	Medical condition prevent the subject from doing the task freely
	Previous orthodontic treatment
	History of congenital facial or oral malformation including cleft lip and palate.
	Previous facial trauma.
	History of facial nerve paralysis or neurologic disorder

Mean ± SD of norms of Japanese people [10]

M: Male

F: Female

Figure 1. Lateral and posterior-anterior (PA) cephalometric landmarks and planes. (a) S, sella; N, Nasion; Po, porion; Or, orbitale; A, subspinale; B, supramentale; U1, incisal edge of upper first incisor; L1, incisal edge of lower first incisor; Me, menton; FH plane, Frankfort horizontal plane; Mandibular plane, tangent line of the lower border of the mandible. (b) Lo (‘), right and left Latero-orbitale; Mo (‘), right and left side of the intersection of the maxillary bone and the maxillary first molar.

Figure 2. Three-dimensional motion capture system for orofacial soft tissue. (a) Two cameras were mounted opposite the participants’ faces. The remaining four cameras were divided into two on each side of the participant and mounted symmetrically at 45° from the participant’s midline. The two cameras at each angle were 70 cm away from the participant’s head and were higher and lower than the patient’s head. The vertical distance between the two cameras at each angle was 35 cm. (b) Facial landmarks were used for the dynamic analysis.

Figure 3. Design of the speech task. The participants repeated the pronunciations series three times. Each session in an alternating pattern consisted of six rest blocks and five speech blocks. The rest block was 3 seconds in duration.

Figure 4. Reference planes in the 3D coordinate system and waveforms representing the motion of each landmark.

Table 2. Descriptive values and statistical calculations for cephalometric variables and irregularity index between each group.

	AFD		SFD		CTRL		Significant differences
	Mean	SD	Mean	SD	Mean	SD	AFD vs SFD	AFD vs CTRL	SFD vs CTRL
Lateral Cephalogram
Males
SNA (°)	80.6	3.9	80.4	4.7	80.5	2.0
SNB (°)	83.8	5.0	85.8	4.3	79.3	2.0			*p=0.004
ANB (°)	- 3.2	2.0	- 5.3	2.7	1.2	1.1		*p=0.004	*p<0.001
Overjet (mm)	- 1.6	2.6	- 2.8	4.3	4.1	1.8		*p=0.005	*p=0.003
Overbite (mm)	- 0.9	1.8	1.8	2.6	1.3	0.8	*p=0.021
Mandibular plane (°)	29.3	3.3	28.1	6.6	23.0	3.9
U1 to FH plane (°)	122.8	7.3	121.2	7.4	119.3	7.1
L1 to Mandibular plane (°)	81.7	6.7	81.4	6.9	100.0	8.7		*p=0.002	*p=0.002
PA cephalogram
Occlusal cant (mm)	2.2	2.0	1.5	1.3	2.0	1.6		*p=0.002	*p=0.002
Menton deviation (mm)	9.4	5.1	2.0	1.0	2.1	1.1	*p<0.001	*p=0.001
Irregularity Index
Upper arch (mm)	9.0	9.4	9.4	5.8	7.6	7.6
Lower arch (mm)	5.2	4.6	4.6	2.9	7.2	7.2
Females
SNA (°)	79.0	1.6	82.0	4.1	78.8	3.9
SNB (°)	81.0	3.4	85.5	4.8	75.4	4.3			* p<0.001
ANB (°)	-2.0	2.1	- 3.5	2.8	3.4	1.3		*p=0.001	*p<0.001
Overjet (mm)	0.1	1.4	-1.1	3.3	3.4	0.8		*p=0.004	*p<0.001
Overbite (mm)	- 0.5	1.8	0.0	2.9	1.9	1.0		*p=0.016	*p=0.019
Mandibular plane (°)	31.6	2.0	30.7	4.9	28.3	6.6
U1 to FH plane (°)	114.8	20.5	125.3	4.8	113.2	6.6			*p<0.001
L1 to Mandibular plane (°)	81.7	10.2	81.1	7.1	96.3	6.0		*p=0.004	*p<0.001
PA cephalogram
Occlusal cant (mm)	2.0	2.4	1.9	1.5	1.4	1.8
Menton deviation (mm)	7.6	2.1	1.9	1.3	1.8	1.1	*p<0.001	*p<0.001
Irregularity Index
Upper arch (mm)	7.6	5.0	9.6	6.3	6.6	4.2
Lower arch (mm)	7.2	3.4	5.1	3.0	9.3	5.2

PA: Posterior-anterior, SD: Standard deviation, SFD: Symmetrical Facial Deformity group, AFD: Asymmetrical Facial Deformity group, CTRL: Control Group, U1 : upper central incisor, L1 : Lower central incisal, FH : Frankfort horizontal plane

Table 3. Comparison of the maximum displacement of landmarks during /apa/ articulation between the three groups

		AFD		SFD		CTRL		Significant difference
Landmark	Axis	Mean	SD	Mean	SD	Mean	SD	AFD vs. SFD	SFD vs. CTRL	AFD vs. CTRL
Upper lip	X	0.014	0.005	0.012	0.003	0.013	0.005
	Y	0.030	0.014	0.045	0.022	0.034	0.012	*p=0.023
	Z	0.053	0.016	0.067	0.027	0.061	0.020
Lower lip	X	0.021	0.006	0.021	0.010	0.086	0.004
	Y	0.105	0.038	0.122	0.073	0.119	0.045
	Z	0.162	0.052	0.163	0.049	0.132	0.036
Right commissure (non-shifted side)	X	0.017	0.004	0.021	0.009	0.018	0.005
	Y	0.061	0.022	0.066	0.036	0.052	0.020
	Z	0.039	0.012	0.042	0.016	0.033	0.011
Left commissure (shifted side)	X	0.017	0.004	0.020	0.008	0.021	0.007
	Y	0.059	0.023	0.066	0.038	0.055	0.022
	Z	0.047	0.018	0.040	0.015	0.035	0.010

The maximum displacement of each landmark on each axis for three groups. Significant between-group difference is indicated by an asterisk.Abbreviations AFD: Asymmetrical facial deformity group, SFD: Symmetrical facial deformity group, CTRL: Control group, X= Lateral axis, Y= Vertical axis. Z= sagittal axis.* p<0.05

** p<0.01

Table 4. Comparison of the maximum displacement of landmarks /ipi/ articulation between the three groups

		AFD		SFD		CTRL		Significant difference
Landmark	Axis	Mean	SD	Mean	SD	Mean	SD	AFD vs. SFD	SFD vs. CTRL	AFD vs. CTRL
Upper lip	X	0.014	0.005	0.014	0.004	0.014	0.005
	Y	0.029	0.013	0.042	0.022	0.031	0.010	* p=0.041
	Z	0.035	0.011	0.039	0.015	0.046	0.014			* p=0.018
Lower lip	X	0.020	0.005	0.019	0.009	0.019	0.005
	Y	0.060	0.025	0.080	0.048	0.084	0.021			* p=0.015
	Z	0.116	0.035	0.113	0.028	0.083	0.023		**p<0.001	**p=0.002
Right commissure (non-shifted side)	X	0.018	0.007	0.021	0.007	0.019	0.007
	Y	0.046	0.016	0.060	0.028	0.048	0.015
	Z	0.032	0.012	0.034	0.011	0.022	0.007		**p=0.002	* p<0.001
Left commissure (shifted side)	X	0.018	0.008	0.021	0.009	0.021	0.012
	Y	0.046	0.015	0.059	0.029	0.050	0.017
	Z	0.039	0.015	0.035	0.013	0.024	0.008		**p=0.010	**p=0.002

The maximum displacement of each landmark on each axis for three groups. Significant between-group differences are indicated by an asterisk.

Abbreviations AFD: Asymmetrical facial deformity group, SFD: Symmetrical facial deformity group, CTRL: Control group, X= Lateral axis, Y= Vertical axis. Z= sagittal axis.

* p<0.05

** p<0.01

Table 5. Comparison of the maximum displacement of landmarks during /upu/ articulation between the three groups

		AFD		SFD		CTRL		Significant difference
Landmark	Axis	Mean	SD	Mean	SD	Mean	SD	AFD vs. SFD	SFD vs. CTRL	AFD vs. CTRL
Upper lip	X	0.012	0.004	0.012	0.004	0.012	0.005
	Y	0.039	0.018	0.046	0.024	0.032	0.013
	Z	0.032	0.009	0.035	0.015	0.038	0.013
Lower lip	X	0.015	0.003	0.015	0.004	0.014	0.004
	Y	0.047	0.017	0.058	0.037	0.056	0.018
	Z	0.064	0.017	0.062	0.023	0.052	0.041		*p=0.048	*p=0.016
Right commissure (non-shifted side)	X	0.021	0.009	0.024	0.014	0.017	0.007
	Y	0.046	0.018	0.056	0.031	0.045	0.020
	Z	0.023	0.008	0.026	0.012	0.018	0.007		*p=0.012
Left commissure (shifted side)	X	0.021	0.009	0.024	0.015	0.019	0.010
	Y	0.048	0.018	0.055	0.030	0.045	0.020
	Z	0.029	0.011	0.027	0.011	0.019	0.007		*p=0.012	*p=0.030

The maximum displacement of each landmark on each axis for three groups. Significant between-group differences are indicated by an asterisk.

Abbreviations AFD: Asymmetrical facial deformity group, SFD: Symmetrical facial deformity group, CTRL: Control group, X= Lateral axis, Y= Vertical axis. Z= sagittal axis.

* p<0.05

** p<0.01

Table 6. Comparison of the maximum displacement of landmarks during /epe/ articulation between the three groups

		AFD		SFD		CTRL		Significant difference
Landmark	Axis	Mean	SD	Mean	SD	Mean	SD	AFD vs. SFD	SFD vs. CTRL	AFD vs. CTRL
Upper lip	X	0.014	0.005	0.013	0.004	0.014	0.005
	Y	0.030	0.014	0.047	0.023	0.037	0.012	**p=0.006
	Z	0.047	0.016	0.061	0.026	0.057	0.017
Lower lip	X	0.021	0.006	0.021	0.009	0.019	0.004
	Y	0.082	0.034	0.091	0.050	0.098	0.034
	Z	0.134	0.040	0.131	0.038	0.108	0.027
Right commissure (non-shifted side)	X	0.018	0.005	0.023	0.011	0.020	0.008
	Y	0.057	0.021	0.068	0.028	0.058	0.016
	Z	0.031	0.012	0.035	0.013	0.025	0.008		*p=0.015
Left commissure (shifted side)	X	0.016	0.005	0.022	0.011	0.023	0.012
	Y	0.057	0.020	0.069	0.031	0.060	0.018
	Z	0.038	0.015	0.034	0.014	0.027	0.009

The maximum displacement of each landmark on each axis for three groups. Significant between-group differences are indicated by an asterisk.

Abbreviations AFD: Asymmetrical facial deformity group, SFD: Symmetrical facial deformity group, CTRL: Control group, X= Lateral axis, Y= Vertical axis. Z= sagittal axis.

* p<0.05

** p<0.01

Table 7. Comparison of the range of movement of landmarks during /opo/ articulation between the three groups

		AFD		SFD		CTRL		Significant difference
Landmark	Axis	Mean	SD	Mean	SD	Mean	SD	AFD vs. SFD	SFD vs. CTRL	AFD vs. CTRL
Upper lip	X	0.013	0.004	0.014	0.005	0.012	0.006
	Y	0.031	0.014	0.043	0.020	0.028	0.009		*p=0.013
	Z	0.044	0.012	0.049	0.021	0.046	0.018
Lower lip	X	0.014	0.004	0.017	0.006	0.015	0.005
	Y	0.058	0.020	0.070	0.040	0.060	0.024
	Z	0.075	0.029	0.076	0.033	0.064	0.038
Right commissure (non-shifted side)	X	0.023	0.010	0.027	0.014	0.020	0.010
	Y	0.042	0.014	0.051	0.023	0.039	0.018
	Z	0.026	0.011	0.028	0.012	0.021	0.006
Left commissure (shifted side)	X	0.023	0.011	0.027	0.014	0.021	0.012
	Y	0.042	0.014	0.052	0.025	0.042	0.019
	Z	0.030	0.014	0.029	0.011	0.027	0.020

The maximum displacement of each landmark on each axis for three groups. Significant between-group differences are indicated by an asterisk.

Abbreviations SFD: Symmetrical facial deformity group, AFD: Asymmetrical facial deformity group, CTRL: Control group, X= Lateral axis, Y= Vertical axis. Z= sagittal axis.

* p<0.05

** p<0.01

Table 8. Comparison of the asymmetry index (AI) during each sound articulation between the three groups

		AFD		SFD		CTRL		Significant difference
Sound articulation	Axis	Mean	SD	Mean	SD	Mean	SD	AFD vs. SFD	SFD vs. CTRL	AFD vs. CTRL
/apa/	X	-0.94	14.03	-0.06	10.96	7.91	13.76
	Y	-1.08	8.27	-0.48	6.08	2.08	5.35
	Z	8.75	11.58	-1.65	16.76	2.93	10.99	*p=0.011
/ipi/	X	-2.63	18.80	0.02	13.74	5.03	13.48
	Y	12.35	11.97	-1.67	6.97	1.59	6.97	**p<0.001		*p=0.026
	Z	18.59	15.94	1.29	18.03	4.28	11.65	**p<0.001		*p=0.013
/upu/	X	0.71	9.81	-1.01	14.97	4.01	13.57
	Y	2.86	8.09	-0.47	6.41	0.41	6.38
	Z	10.26	14.30	1.29	10.88	1.53	12.85			**p=0.030
/epe/	X	-4.89	14.23	-1.61	14.76	4.14	11.27
	Y	0.52	8.70	-0.16	5.70	1.50	5.59
	Z	10.58	12.85	-1.06	16.56	2.59	11.02	**p=0.005
/opo/	X	-0.87	10.61	1.00	12.97	-0.46	13.70
	Y	0.16	6.74	-0.21	5.04	3.25	7.74
	Z	7.41	12.95	3.32	11.74	4.36	20.04

Abbreviations AFD: Asymmetrical facial deformity group, SFD: Symmetrical facial deformity group, CTRL: Control group, X= Lateral axis, Y= Vertical axis. Z= sagittal axis.

The AI (%) on each axis for three groups. Significant between-group difference is indicated by an asterisk.

* p<0.05

** p<0.01

Figure 5. Correlation between the menton deviations and the asymmetry index (AI) of the two commissure points in the facial deformity patients (SFD and AFD groups).

Iizuka T, Ishikawa H. Normal standards for various cephalometric analysis in Japanese adults. J Japan Orthodontic Soc. 1957;16:4–12.

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Data availability statement

The datasets used and analyzed during the current study are available from the corresponding author, KM, upon reasonable request.