Internal Fit of Single Crowns Produced by CAD/CAM and Lost-wax Metal Casting Technique Assessed by the Triple-scan Protocol

Objectives: To digitally study the internal fit of single crown fixed dental prostheses produced by CAD/CAM and by lost-wax and metal casting techniques.
Methods: On an upper jaw simulator with KaVo typodont teeth, the left insisor was prepared for single crown. Impression and scans were taken and three copings were manufactured from each group: milled pre-sintered zirconia, milled hot isostatic pressed zirconia, milled lithium disilicate, milled cobalt-chromium, and laser-sintered cobalt-chromium using CAD/CAM technique and cobalt-chromium by the conventional lost-wax and metal casting technique.
The internal fit of crowns produced by CAD/CAM technique was compared to crowns produced by metal casting technique. The internal fit was evaluated in buccal-palatinal and in mesio-distal directions using the triple-scan protocol and GOM Inspect software.
Results: The internal gaps in mesio-distal and buccal-palatinal directions were statistically smaller for crowns made by conventional lost-wax and metal casting technique compared to crowns produced by CAD/CAM technique (Table 1).
Conclusions: The triple-scan method revealed that single crowns made by lost-wax and metal casting technique had better internal fit than crowns produced by CAD/CAM technique.