Dimensional accuracy of microcomputed tomography-scanned half-arch impressions

Area of Science:

• Dental Technology
• Digital Dentistry
• Imaging Techniques

Background:

• Direct digitization of physical dental impressions can improve accuracy by avoiding errors associated with gypsum casts.
• Traditional methods of impression making and casting can introduce inaccuracies.

Purpose of the Study:

• To compare the dimensional accuracy of microcomputed tomography (micro-CT) scans of dental impressions against optical scans of impressions and gypsum casts.
• To evaluate the efficacy of micro-CT scanning for digitizing physical dental impressions.

Main Methods:

• A titanium maxillary cast with reference ruby spheres was used.
• Half-arch impressions were made using polyvinyl siloxane material.
• Impressions were scanned using micro-CT and optical methods; stone casts were optically scanned.
• Distances between spheres were measured and compared to the reference model.

Main Results:

• Optical scans of stone casts showed higher accuracy (0 ±20 μm) than micro-CT scans (20 ±20 μm) at a 25.036 mm distance.
• At a 41.846 mm distance, micro-CT scans (0 ±40 μm) demonstrated less error than optical scans of stone casts (-40 ±40 μm).
• Optical scanning of impressions was excluded due to data loss and deformation.

Conclusions:

• Micro-CT scanning of dental impressions is a feasible method for digitizing oral structures.
• For long-span restorations, digital images from micro-CT scanning of impressions are more accurate than those from optical scans of stone casts.
• Dimensional accuracy varies between techniques depending on the measured distance.