A Novel Method to Combine Maxilla-Based Coordinate System and Mandibular Voxel-Based Superimposition with Cone-Bean...

Area of Science:

• Orthodontics
• Craniofacial analysis
• Biomedical imaging

Background:

• Accurate assessment of mandibular structural and positional changes is crucial in orthodontics.
• Direct comparison of maxillary and mandibular changes requires a standardized approach.
• Existing methods may not fully capture complex 3D skeletal movements.

Purpose of the Study:

• To propose and validate a novel method for evaluating mandibular structural and positional changes.
• To enable direct comparison of maxillary and mandibular structural changes using unified 3D vectors.
• To enhance the accuracy and reproducibility of craniofacial change analysis.

Main Methods:

• A maxilla-based coordinate system was established using key skeletal landmarks (ANS, PNS, OrL, OrR).
• Mandibular voxel-based superimposition was employed to eliminate positional variations.
• The reoriented mandible was analyzed within the maxilla-based coordinate system using CBCT data.

Main Results:

• The proposed method demonstrated high accuracy and reproducibility, with an ICC of 0.99 for observer agreement.
• Mandibular voxel-based superimposition effectively eliminated positional changes, as evidenced by non-significant structural measurements post-superimposition.
• Significant linear and angular differences in mandibular structures were detected before superimposition, indicating positional shifts.

Conclusions:

• The combined maxilla-based coordinate system and mandibular voxel-based superimposition method offers superior accuracy, reproducibility, and validity.
• This technique facilitates precise evaluation of both structural and positional mandibular changes.
• It enables direct, vector-based comparisons between maxillary and mandibular structural alterations.