United Reference Method for three-dimensional treatment evaluation.

Area of Science:

• Dentistry and Oral Surgery
• Medical Imaging
• Orthodontics

Background:

• Three-dimensional (3D) treatment evaluation is crucial for enhancing future treatments with realistic outcomes.
• Current methods lack reproducibility and descriptive capabilities for complex craniofacial changes.

Purpose of the Study:

• To introduce and describe the United Reference Method (URM) for 3D craniofacial treatment evaluation.
• To demonstrate the use of fully-automated craniofacial superimposition of CBCT records with a reference system for obtaining descriptive and comparable results.

Main Methods:

• The URM combines automated 3D superimposition on the anterior cranial base with a reference system for measurements.
• It involves automated superimposition, semi-automated landmark identification (including corrected Frankfort Horizontal plane and Sella point), and head orientation.
• Measurements are derived from projections of pre- and post-treatment landmarks onto the corrected Frankfort Horizontal plane, with reliability assessed using Intra-class Correlation Coefficient (ICC) and standard deviation (SD).

Main Results:

• The URM demonstrated high reliability for C-FH construction coordinates (ICC ≥ 0.998, SD 0.064–0.242 mm).
• Coordinates excluded due to natural asymmetry showed lower reliability (ICC ≥ 0.742, SD up to 1.112 mm).

Conclusions:

• The United Reference Method (URM) exhibits adequate reliability for 3D craniofacial structural change assessment.
• URM can generate descriptive and comparable 3D data, supporting improved treatment evaluation and planning.