Stress and displacement patterns in the craniofacial skeleton with rapid maxillary expansion—a finite element method study

Progress in Orthodontics

Table 1 Computational result of the transversal (X), sagittal (Y), and vertical (Z) displacements of the various skeletal structures of the craniofacial complex following 5 mm of transverse expansion on application of 19 kg/mm² force

Region	Selected node	X (mm)	Y (mm)	Z (mm)
Dentoalveolar	Incisal edge of 1 (47,005)	5.073	0.79	0.42
	Cusp tip 3 (44,665)	5.068	0.65	0.28
	Cusp tip 6 (35,146)	5.068	0.69	0.28
	Apical region of 1 (106,126)	4.281	0.93	−0.62
	Apical region of 3 (99,505)	3.878	0.43	0.28
	Apical region of 6 (112,557)	4.273	0.37	0.32
Palate	Anterior part of palate (17,631)	3.077	1.21	−0.81
Palate	Posterior part (17,161)	2.09	1.12	−0.98
Maxilla	Point “A” (32,324)	3.55	0.86	−0.92
	ANS (16,022)	3.078	1.24	−0.72
	Tuberosity (12,721)	3.26	0.55	0.32
	Zygomatic buttress (11,611)	2.89	0.019	0.85
	Inferior orbital rim (10,586)	1.97	−0.21	0.90
	Frontal process (14,235)	1.00	0.078	−0.22
Nasal cavity wall	Antero-inferior (17,902)	2.95	0.43	0.02
	Anterosuperior (14,894)	1.41	0.21	−0.02
	Posteroinferior (14,131)	1.93	0.42	−0.35
	Posterosuperior (17,005)	0.49	0.009	−0.04
Nasal bone	Body (16,523)	0.31	−0.63	−0.71
Sphenoid bone	Lateral pterygoid inferior (24,419)	1.91	0.63	−0.52
	Lateral pterygoid superior (24,118)	0.651	0.06	0.18
	Medial pterygoid inferior (20,674)	1.88	−0.53	−0.39
	Medial pterygoid superior (24,011)	0.146	−0.09	0.23
	Greater wing (29,115)	0.33	−0.41	0.67
Zygomatic bone	Body (5320)	0.25	−0.83	1.64
	Frontal process (22,309)	2.19	−1.2	1.62
	Zygomatic arch anterior (3971)	0.55	−0.86	1.72
	Zygomatic arch posterior (3907)	0.045	−0.42	0.08
Frontal bone	Supraorbital (7846)	0.015	−0.02	0.12
Frontal bone	Forehead (18,937)	0.02	−0.03	0.065
Temporal bone	Squamous (3786)	0.55	−0.28	0.36
Parietal	Tuberosity (31,299)	0.09	−0.27	0.41
Occipital	Squamous (20,670)	0.014	−0.09	0.03