Analysis of Three-Dimensional Morphological Differences in the Mandible between Skeletal Class I and Class II with CBCT Fixed-Point Measurement Method

Table 1

The abbreviations and definitions of the landmarks.

Landmarks	Abbreviation	Definition
Coordinate system points
Nasion	N	The most anterior point of the nasal frontal suture
Right porion	Po-R	The uppermost point of right external auditory canal
Right orbitale	Or-R	The lowest point of the right infraorbital margin
Anterior nasal spine	ANS	The apex of the anterior nasal ridge
Basion	Ba	The midpoint of the anterior edge of foramen magnum
Single points
Sellar	S	The central point of the pituitary fossa
A	A	The most concave point of the bone between the point of anterior nasal ridge and the point of superior alveolar margin
B	B	The most concave point of the bone between the point of the inferior alveolar margin and the point of the anterior chin
Gnathion	Gn	The midpoint between the anterior point of chin and the submental point
Menton	Men	The lowest point of the chin
Ig	Ig	The apex of alveoli between lower central incisors
Paired points
Left gonion	Go-L	Posterior inferior point of left mandibular angle
Right gonion	Go-R	Posterior inferior point of right mandibular angle
Internal point of left condyle	Co-L	The uppermost point of the left condyle
Internal point of right condyle	Co-R	The uppermost point of the right condyle
External point of left condyle	CdML	The innermost point of the left condyle
External point of right condyle	CdMR	The innermost point of the right condyle
Anterior point of left condyle	CdAL	The most lateral point of the left condyle
Anterior point of right condyle	CdAR	The most lateral point of the right condyle
Posterior point of left condyle	CdPL	The last point of the left condyle
Posterior point of right condyle	CdPR	The last point of the right condyle
Apex of left coracoid process	Cc-L	The uppermost point of the left coracoid process
Apex of right coracoid process	Cc-R	The uppermost point of the right coracoid process
Left sigmoid notch	Sg-L	The lowest point of the left sigmoid notch
Right sigmoid notch	Sg-R	The lowest point of the right sigmoid notch
Left mandibular inflection	Ma-L	The most concave and outermost point between left anterior edge of ramus and mandibular body turning point
Right mandibular inflection	Ma-R	The most concave and outermost point between right anterior edge of ramus and mandibular body turning point
Left mental foramen	Mf-L	The lateral superior point of the left mental foramen on the anterior surface of the mandible
Right mental foramen	Mf-R	The lateral superior point of the right mental foramen on the anterior surface of the mandible