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Denture fabrication distortion

Background

Complete dentures are designed to achieve excellent adaptation to mucosa that produces good retention, stability, and support. The fabrication process, however, can introduce some distortion, whether it is by compression molding, pouring a fluid resin, or injection molding—three popular methods of denture processing. A new technique for denture fabrication uses computer-aided design and computer-aided manufacturing (CAD-CAM) techniques involving pre-polymerized blocks of polymethyl methacrylate

Methods

Forty gypsum casts were laser scanned before fabrication, then a master denture was made using the CAD-CAM process, which was used to create a putty mold so that 30 standardized wax festooned dentures could be fabricated. These were divided into three groups of 10 each for processing using the pack and press, pour, or injection techniques. Scan files from 10 casts were sent for fabrication of CAD-CAM test specimens. All the 40 specimens were hydrated for 24 hours before the intaglio surface was

Results

Ideally, none of the casts would show processing deformation and would demonstrate perfect adaptation of the denture base to the cast. All of the methods demonstrated some degree of deformation. The CAD-CAM technique had the most uniform distribution of adaptation, and the pack and press technique had the least uniform distribution.

At the apex of the denture border, no statistically significant difference was noted between CAD-CAM and pack and press specimens. CAD-CAM distortion and pack and

Discussion

Dentures deform during processing, which can affect the retention, stability, and support provided by the final denture. Limiting any deformation to the minimum is the goal of refinements in the processing techniques. CAD-CAM appears to be a more accurate and reproducible technique than any of the others currently used.