Lower face cephalometry based on quadrilateral analysis with cone-beam computed tomography: a clinical pilot study

Area of Science:

• Dentistry
• Oral and Maxillofacial Surgery
• Medical Imaging

Background:

• Orthognathic surgery often focuses on the lower face.
• Existing 2D cephalometry provides useful data but can be limited.
• Millimeter-based data is preferred by surgeons over angular measurements.

Purpose of the Study:

• To adapt a 2D quadrilateral lower face analysis to 3D cephalometry using CBCT.
• To develop a 3D lower face analysis based on quadrilateral principles.
• To establish a reference table for surgical planning in millimeters.

Main Methods:

• Three investigators analyzed CBCT images from 30 patients with normocclusion.
• 16 landmarks were identified, and intra-class correlation coefficients (ICCs) and standard deviations (SDs) were calculated.
• Facial asymmetry and coherence were assessed using statistical models.

Main Results:

• ICCs were high (≥0.90), and landmark SDs were generally below 1.00 mm.
• Linear measurements showed SDs between 3.06-5.20 mm with no significant facial asymmetry.
• A floating norm for the lower face was established using five regression models.

Conclusions:

• The 3D adaptation of quadrilateral analysis accurately characterizes lower face morphology.
• The millimeter-based floating norm is practical for surgeons in orthognathic surgery.
• This 3D approach offers a potentially accurate method for presurgical planning.