Internal fit of single crowns produced by CAD-CAM and lost-wax metal casting technique assessed by the triple-scan protocol.
BACKGROUND
Whether single crowns produced by computer-aided design and computer-aided manufacturing (CAD-CAM) have an internal fit comparable to crowns made by lost-wax metal casting technique is unknown.


OBJECTIVE
The purpose of this in vitro study was to compare the internal fit of single crowns produced with the lost-wax and metal casting technique with that of single crowns produced with the CAD-CAM technique.


METHODS
The internal fit of 5 groups of single crowns produced with the CAD-CAM technique was compared with that of single crowns produced in cobalt-chromium with the conventional lost-wax and metal casting technique. Comparison was performed using the triple-scan protocol; scans of the master model, the crown on the master model, and the intaglio of the crown were superimposed and analyzed with computer software. The 5 groups were milled presintered zirconia, milled hot isostatic pressed zirconia, milled lithium disilicate, milled cobalt-chromium, and laser-sintered cobalt-chromium.


RESULTS
The cement space in both the mesiodistal and buccopalatal directions was statistically smaller (P<.05) for crowns made by the conventional lost-wax and metal casting technique compared with that of crowns produced by the CAD-CAM technique.


CONCLUSIONS
Single crowns made using the conventional lost-wax and metal casting technique have better internal fit than crowns produced using the CAD-CAM technique.
Doctoral student, Department of Prosthetic Dentistry, Institute of Clinical Dentistry, Dental Faculty, University of Oslo, Oslo, Norway. Electronic address: b.e.dahl@odont.uio.no.
Bjørn Einar
BE
Dahl
Associate Professor, Department of Prosthetic Dentistry, Institute of Clinical Dentistry, Dental Faculty, University of Oslo, Oslo, Norway.
Hans Jacob
HJ
Rønold
Professor, Institute of Clinical Dentistry, Dental Faculty, University of Oslo, Oslo, Norway; and CEO, Nordic Institute of Dental Materials, Oslo, Norway.
Jon E
JE
Dahl
D002858:Chromium Alloys / Q000737:chemistry; D017076:Computer-Aided Design; D003442:Crowns; D000044:Dental Abutments; D003735:Dental Casting Technique; D003738:Dental Cements; D003761:Dental Impression Technique; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design / Q000379:methods*; D006801:Humans; D007834:Lasers; D016876:Metal Ceramic Alloys / Q000737:chemistry; D013499:Surface Properties; D015040:Zirconium
D002858:Chromium Alloys; D003738:Dental Cements; D016876:Metal Ceramic Alloys; C493120:lithia disilicate; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide