Table 1.

Study landmarks and reference planes

Landmarks			Definition	Sagittal slice	Axial slice	Coronal slice
Dental	Mx1	Maxillary central incisors	Incisal contact point of the maxillary central incisors	Inferior-most point	Contact point	Incisal embrasure
	Md1	Mandibular central incisors	Incisal contact point of the mandibular central incisors	Inferior-most point	Contact point	Incisal embrasure
	Mx3R and Mx3L	Maxillary canine	Cusp tip of the maxillary canine	Inferior-most point	First point that appears	Inferior-most point
	Md3R and Mx3L	Mandibular canine	Cusp tip of the mandibular canine	Superior-most point	First point that appears	Superior-most point
	Mx6R and Mx6L	Maxillary first molar	Mesiobuccal cusp tip of the maxillary first molar	Inferior-most point	First point that appears	Middle-inferior-most point
	Md6R and Mx6L	Mandibular first molar	Buccal groove of the mandibular first molar	Inferior-most point between the buccal cusps	First point that appears	Superior-most point in line with the buccal cusps
Midface	ANS	Anterior nasal spine	The most anterior midpoint of the anterior nasal spine of the maxilla	Lateral-most point	Superior-most point	First point that appears
	PNS	Posterior nasal spine	The most posterior midpoint of the posterior nasal spine of the palatine bone	Lateral-most point	Inferior-most point	First point that appears
	OrR and OrL	Orbitale	The most inferior point on the infraorbital rim of the maxilla	Inferior-most point of the infraorbital rim	Anterior-most point	Inferior-most point of the infraorbital rim
	FZSR and FZSL	Frontozygomatic suture	The most superior and medial point on the frontozygomatic suture	Superior-most point	Anterior-most point	Medial-superior most point
	FPMR and FPML	Frontal process of maxilla	Intersection of the frontal process of the maxilla, frontal bone and lacrimal bone	Superior-most point	Anterior-most point	Medial-superior most point
Mandible	Me	Menton	The most inferior midpoint of the chin on the outline of the mandibular symphysis	Inferior-most point	First point that appears	Middle-most point along the inferior border
	Pg	Pogonion	The most anterior midpoint of the chin on the outline of the mandibular symphysis	Inferior-most point	Superior-most point	First point that appears
	GoR and GoL	Gonion	The midpoint on the angle of the mandible, half way between the corpus and ramus	Middle-most point along the angle of the mandible	Middle-inferior-most point	Middle-inferior-most point
	CdSR and CdSL	Condyle superior	The most superior point of the condylar head	Superior-most point	First point that appears	Superior-most point
	CdLR and CdLL	Condyle lateral pole	The most lateral point of the condylar head	First point that appears	Lateral-most point of the widest section of the condyle	Lateral-most point
	CdMR and CdML	Condyle medial pole	The most medial point of the condylar head	First point that appears	Medial-most point of the widest section of the condyle	Medial-most point
	CdAR and CdAL	Condyle anterior	The most anterior point of the condylar head	Anterior-most point	Middle-most point on the anterior surface of the widest section of the condyle	Medial-most point
	CdPR and CdAL	Condyle posterior	The most posterior point of the condylar head	Posterior-most point	Middle-most point on the posterior surface of the widest section of the condyle	N/A
Temporal bone	GlSR and GlSL	Glenoid fossa superior	The most superior point of the glenoid fossa of the temporal bone	Superior-most point	First point that appears	Superior-most point
	GlAR and GlAL	Glenoid fossa Anterior	The most inferior point of the articular eminence of the temporal bone	Inferior-most point on the articular eminence	Anterior-most point	Superior-most point
	PoR and PoL	Porion	The most superior point of the external acoustic meatus	Superior-most point of the external acoustic meatus	First point that appears	Superior-most point of the external acoustic meatus
Reference planes
Axial plane			A plane that connects the most superior point of the external acoustic meatus with the most inferior point of the infraorbital rim on the right and left sides
Sagittal plane			A plane constructed using paired midfacial anatomic structures (eg., the orbits, frontal process of the maxilla, frontozygomatic suture)
Coronal plane			A plane constructed from the transporionic line