The Airway Volume Related to the Maxillo-Mandibular Position Using 3D Analysis

Table 1

Comparative picture of the cephalometric points and normality parameters used.

	Steiner		McNamara		Ricketts
Mx position	S-Na-A point	82°	Po-Or/Na-perpendicular	1 mm	Po-Or/Na-A point	90°
Mn position	S-Na-B point	80°	Po-Or/Na-perpendicular		Po-Or/Na-Pog
Angulation Mn plane	S-Na/Go-Gn	32°	Po-Or/Go-Me	25°	Po-Or/Go-Gn
Mx incisor inclination	Na-A point/incisor edge	4 mm	Na-A point/up. buccal	4 mm	A point-Pog/up. vestibular	3.5 mm
Mn incisor inclination	Na-B point/incisor edge	4 mm	Na-Pog/up. vestibular	3 mm	A point-Pog/up. vestibular	1 mm

Mn: mandible; Mx: maxilla; S: point located at the geometric centre of the sella turcica; Na: most anterior point of the frontonasal suture; A point: point located in the most anterior region of the anterior maxillary concavity; B point: point located in the most anterior region of the anterior mandibular concavity; Go: point located in the most posterior and lowest parts of the mandibular angle; Gn: most anterior and lowest points of the anterior edge of the mandibular symphysis, normally located between the menton and pogonion; Me: lowest point of the mandibular symphysis; Po: highest point of the external auditory canal; Or: lowest point of the orbit; Pog: most anterior point on the anterior edge of the mandibular symphysis.