A voxel-based CBCT superimposition of upper molar distalisation using clear aligners in conjunction with Class II elastics

Zhang, Mingxin; Liu, Xulin; Zhang, Ruijie; Wang, Axian; Zhang, Yubohan; Ma, Yanning; Jin, Zuolin

doi:10.2478/aoj-2025-0033

Figures & Tables

Voxel-based superimposition using Dolphin software. A. Landmarks for maxillary superimposition; B. Landmarks for mandibular superimposition.

Measurement of tooth movements. A. Disto-mesial tipping angles of the upper molars and labio-lingual tipping angles of the upper incisors; B. Disto-mesial tipping angles of the lower molars and labio-lingual tipping angles of the lower incisors; C. Rotation angle of the upper molars; D. Rotation angle of the lower molars; E. Displacement of the upper molars; F. Displacement of the lower molars.

Scatter diagram, Pearson’s correlation coefficients, and simple linear regression analyses of the predicted upper molar distalisation and achieved tooth movement.Table III. Multiple linear regression models for predicted and achieved tooth movements

Multiple linear regression models for predicted and achieved tooth movements

Variables	Unstandard coefficients		95.0% CI		Standard coefficients	t value	P value
Variables	B	SE	Lower	Upper	β	t value	P value
Achieved upper molar distalization
Intercept	0.120	0.097	–0.075	0.316		1.236	0.222
Predicted molar distalization	0.573	0.028	0.518	0.629	0.940	20.580	0.000*
Sex	–0.089	0.059	–0.207	0.030	–0.070	–1.506	0.138
Attachment
No attachment	Reference
Horizontal	0.035	0.064	–0.093	0.163	0.027	0.551	0.584
Vertical	0.010	0.072	–0.135	0.155	0.007	0.139	0.890
Crowding
No crowding	Reference
Mild crowding	–0.042	0.070	–0.184	0.099	–0.034	–0.603	0.549
Moderate crowding	–0.056	0.077	–0.211	0.098	–0.040	–0.734	0.466
Upper molar distal tipping
Intercept	1.698	0.369	0.958	2.438		4.606	0.000
Predicted molar distalization	0.955	0.108	0.739	1.171	0.756	8.861	0.000*
Sex	–0.223	0.233	–0.690	0.245	–0.085	–0.956	0.343
Attachment
No attachment	Reference
Horizontal	–0.659	0.251	–1.163	–0.156	–0.248	–2.629	0.011*
Vertical	–1.981	0.280	–2.542	–1.419	–0.686	–7.078	0.000*
Crowding
No crowding	Reference
Mild crowding	0.560	0.272	0.014	1.105	0.215	2.060	0.044*
Moderate crowding	0.093	0.294	–0.497	0.683	0.032	0.316	0.753
Upper molar rotation
Intercept	1.325	0.341	0.642	2.008		3.890	0.000
Predicted molar distalization	1.004	0.100	0.804	1.203	0.847	10.083	0.000*
Sex	–0.189	0.215	–0.620	0.243	–0.077	–0.876	0.385
Attachment
No attachment	Reference
Horizontal	–0.016	0.232	–0.481	0.449	–0.006	–0.068	0.946
Vertical	–1.100	0.258	–1.619	–0.582	–0.406	–4.257	0.000*
Crowding
No crowding	Reference
Mild crowding	0.265	0.251	–0.239	0.768	0.109	1.055	0.296
Moderate crowding	–0.269	0.272	–0.814	0.276	–0.098	–0.991	0.326
Lower molar mesialization
Intercept	0.125	0.080	–0.036	0.285		1.559	0.125
Predicted molar distalization	0.183	0.028	0.127	0.238	0.714	6.568	0.000*
Sex	–0.012	0.056	–0.124	0.100	–0.023	–0.216	0.830
Attachment
No attachment	Reference
Horizontal	–0.053	0.057	–0.167	0.060	–0.099	–0.944	0.350
Vertical	–0.026	0.066	–0.158	0.106	–0.044	–0.393	0.696
Crowding
No crowding	Reference
Mild crowding	0.077	0.069	–0.061	0.215	0.146	1.121	0.267
Moderate crowding	0.083	0.089	–0.095	0.261	0.133	0.936	0.354
Upper incisors tipping
Intercept	1.481	0.289	0.901	2.062		5.125	0.000
Predicted molar distalization	0.855	0.084	0.686	1.025	0.804	10.126	0.000*
Sex	–0.273	0.183	–0.639	0.094	–0.123	–1.493	0.142
Attachment
No attachment	Reference
Horizontal	–0.230	0.197	–0.624	0.165	–0.103	–1.168	0.248
Vertical	–0.007	0.219	–0.447	0.434	–0.003	–0.030	0.976
Crowding
No crowding	Reference
Mild crowding	0.279	0.213	–0.148	0.706	0.127	1.310	0.196
Moderate crowding	0.766	0.231	0.303	1.229	0.309	3.322	0.002*
Lower incisors tipping
Intercept	0.196	0.264	–0.334	0.727		0.743	0.461
Predicted molar distalization	0.811	0.092	0.627	0.996	0.745	8.840	0.000*
Sex	–0.183	0.185	–0.554	0.187	–0.081	–0.994	0.325
Attachment
No attachment	Reference
Horizontal	–0.124	0.187	–0.499	0.250	–0.054	–0.666	0.509
Vertical	–0.030	0.218	–0.467	0.406	–0.012	–0.139	0.890
Crowding
No crowding	Reference
Mild crowding	0.499	0.227	0.044	0.955	0.223	2.201	0.032*
Moderate crowding	0.752	0.293	0.164	1.340	0.284	2.568	0.013*

Maxillary and mandibular landmarks

Maxillary landmarks
1	OrR	The inferiormost aspect of the right orbital cavity
2	OrL	The inferiormost aspect of the left orbital cavity.
3	N	The anteriormost point along the nasofrontal suture.
4	ANS	The apex of the anterior nasal spine
5	PNS	The apex of the posterior nasal spine
Mandibular landmarks
1	MfR	The anteriormost point of the right mental foramen
2	MfL	The anteriormost point of the left mental foramen
3	GoR	The midpoint along the bony border of the right mandibular angle
4	GoL	The midpoint along the bony border of the left mandibular angle
5	Gn	The point where the mid-sagittal plane intersects the lowest point of the mandibular symphysis

Descriptive statistics

	Mean	SD	n
Upper molar distalization efficiency (%)	0.60	0.07	60
Upper incisors labial tipping (°)	3.84	1.10	60
Upper molar distal tipping (°)	3.67	1.31	60
Upper molar disto-buccal rotation (°)	3.70	1.23	60
Upper molar buccal tipping (°)	0.99	0.33	60
Lower molar mesialization (mm)	0.64	0.27	60
Lower molar lingual tipping (°)	0.75	0.43	60
Lower molar mesial tipping (°)	1.93	0.99	60
Lower incisors labial tipping (°)	2.61	1.13	60

A voxel-based CBCT superimposition of upper molar distalisation using clear aligners in conjunction with Class II elastics

Figures & Tables

Figure 1.

Figure 2.

Figure 3.

Multiple linear regression models for predicted and achieved tooth movements

Maxillary and mandibular landmarks

Descriptive statistics

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