Table 1.

Definition of Landmarks and Reference Planes Used to Assess Changes in CBCT Images Before and After Expansion

Term	Definition
Nasal cavity width (linear distance)	Distance between the most lateral point of each side of the nasal cavity
Midpalatal suture opening (linear distance)	Distance between the two halves of the ANS and PNS after split
Alveolar bone width (linear distance)	From the lowest point of the alveolar bone crest to the opposite side
Interdental distance (linear distance)	Distance between the middle fossa of right and left upper first premolars and molars
Tooth inclination (degrees)	Long axis of the first premolar and molar to the palatal base of the maxilla

ANS indicates anterior nasal spine; PNS, posterior nasal spine.