Estimating Molar Root Volume from Panoramic Radiographs Using a Geometric Approach-An Experimental Method Comparison.

Area of Science:

• Dental imaging
• Oral and maxillofacial surgery
• Radiology

Background:

• Jaw augmentation assessment typically requires pre- and postoperative tomographic imaging.
• Minimizing radiation exposure is an ethical imperative in medical imaging.
• Panoramic radiography (PR) offers a lower radiation dose than cone-beam CT (CBCT).

Purpose of the Study:

• To explore the feasibility of estimating tooth root volume using panoramic radiographs.
• To develop a mathematical model for tooth root volume assessment from 2D PR.
• To enable safer clinical assessments with reduced radiation exposure.

Main Methods:

• A mathematical approximation method was developed using elliptical and cuboid models for the 2D tooth root surface.
• True root volumes were obtained from CBCT scans (3D).
• A correlation factor 'r' was calculated to relate root surface area from PR to root depth, addressing the missing dimension in 2D imaging.

Main Results:

• The mathematical model was applied to 27 molars, with an average CBCT volume of 472.83 mm³.
• The calculated correlation factor 'r' was 8.04 (±1.90).
• The cuboid model using 'r' yielded an estimated average molar volume of 472.37 mm³ (±152.92), which was not significantly different from CBCT volumes.

Conclusions:

• A mathematical model utilizing elliptical projections from panoramic radiographs can reliably estimate molar root volume.
• This method provides comparable results to CBCT.
• It offers a significant reduction in radiation exposure for patients undergoing jaw augmentation assessments.