Influence of maxillary posterior dentoalveolar discrepancy on angulation of maxillary molars in individuals with skeletal open bite

Arriola-Guillén, Luis Ernesto; Aliaga-Del Castillo, Aron; Flores-Mir, Carlos

doi:10.1186/s40510-016-0147-8

Progress in Orthodontics

Table 2 Definitions of cephalometric points and angles used in this study

From: Influence of maxillary posterior dentoalveolar discrepancy on angulation of maxillary molars in individuals with skeletal open bite

Angular measurements	Definition
SNA	The angle between points sella (S), nasion (N), and subnasal (A) in degrees [16]
SNB	The angle between points sella (S), nasion (N), and supra mental (B) in degrees [16]
ANB	The angle to assess the skeletal relationship between points A and B in degrees [16]
APDI	The anterior-posterior dysplasia indicator to assess the skeletal relationship and is obtained from the algebraic sum of the angles N-Pg-FH (facial plane) plus/minus the angle AB-facial lane (is positive when the point B is ahead of point A and is negative when the point A is ahead of point B) and plus/minus the angle FH-PP (palatal plane) (is negative when PP is tilted upward and positive when tilted down) [17]
FMP	The angle between the porion-orbital line and mandibular line in degrees
ODI	The overbite depth indicator to assess the tendency toward open bite is obtained from the algebraic sum of the angles AB-MP plus/minus the angle FH-PP (palatal plane) and is negative when PP is tilted upward and positive when tilted down [18]
Maxillary first molar angulation	The angle formed by the maxillary first molar axis (intercuspid groove-bifurcation) and the palatal plane (ANS-PNS), represented by a horizontal line
Maxillary second molar angulation	The angle formed by the maxillary second molar axis (intercuspid groove-bifurcation) and the palatal plane (ANS-PNS), represented by a horizontal line
Linear measurements	Definition
A′P′	The distance between the perpendicular extensions of points A and P on the palatal plane (A′P′) in millimeters: point A′ is the perpendicular projection of point A to the palatal plane and point P′ is the perpendicular projection of the posterior—most point of the maxillary tuberosity to the palatal plane [6, 9, 19]
A′6′	The distance between A′ and 6′ in millimeters, the anterior maxillary base length is defined by the measurement between A′ and 6′. Point 6′ is the perpendicular projection of the anterior-most point on the proximal surface of the maxillary first molar to the palatal plane [6, 9, 19]
Ratio (A′6′/A′P′)	The ratio of the anterior maxillary base length A′6′ to the maxillary base length A′P′ (A′6′/A′P′) [6, 9, 19]
Overbite	The overbite in millimeters is the distance between incisal edge of maxillary and mandibular central incisor, perpendicular to occlusal plane [20]
Lower anterior facial height (LAFH)	The length in millimeters of a line between points anterior nasal spine (ANS) and mental (Me) [21]
Ratio facial height (S-Go/N-Me × 100)	The ratio of posterior facial height and anterior facial height [22]

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