Two imaging techniques for 3D quantification of pre-cementation space for CAD/CAM crowns

Area of Science:

• Biomaterials Science
• Dental Technology
• Metrology

Background:

• The three-dimensional (3D) internal fit of dental prostheses to prepared teeth is crucial for clinical success.
• Assessing marginal opening alone may not fully represent the overall prosthesis fit.
• Quantitative methods are needed to evaluate 3D fit and compare CAD/CAM systems.

Purpose of the Study:

• To quantitatively evaluate two techniques for defining 3D prosthesis fit using pre-cementation space impressions.
• To compare X-ray microcomputed tomography (micro-CT) and quantitative optical analysis for this purpose.

Main Methods:

• Pre-cementation space impressions of a zirconia coping on its die were created using poly(vinyl siloxane).
• Calibration specimens were fabricated and analyzed using both micro-CT and quantitative optical analysis.
• Regression analysis compared calibration data from both techniques.

Main Results:

• Micro-CT demonstrated tighter confidence intervals and a wider measurement range compared to the optical technique.
• Optical analysis was more effective for analyzing specific regions and extremely thin impression walls (<10-15μm).
• Micro-CT offered easier specimen preparation and accurate dimension capture with its segmentation parameters.

Conclusions:

• Both micro-CT and optical analysis are viable methods for quantifying pre-cementation space impression thickness.
• Each technique presents distinct advantages and limitations.
• Either method holds potential for clinical studies or optimizing CAD/CAM protocols.