Résumé
The purpose of this study was to evaluate marginal fit of four all-ceramic crown systems 1) conventional In-Ceram, 2) copy-milled In-Ceram using Celay system, 3) IPS Empress, 4) OPC(Optimal Pressable Ceramic). All ceramic crowns were made on epoxy dies. The fabricated crowns were sandblasted, cleaned with ultrasonic cleansing, silanated, and cemented with Bistite composite resin cement. The selected marginal areas of the crowns were the labial, lingual, mesial, and distal surface. Each selected area of surface was 0.6Xl.6mm in dimension. The image of each marginal area was captured to computer files using DT-55 Frame Grabber and light microscope connected CCD camera. The marginal gaps were measured every 70mm using computer image analysis program. The results obtained were summarized as follows : 1. The marginal fit of four all-ceramic crowns were significantly different from each other(p<0.01), and mean marginal fit values obtained were 31.42 +/- 16.52mm in conventional In-Ceram, 55.45 +/- 27.90mm in copy-milled In-Ceram using Celay-system, 44.36 +/- 24.59mm in IPS Empress, 47.21 +/- 20.42mm in OPC. 2. In the marginal fit of conventional In-Cerani and copy-milled In-Ceram crowns using Celay-system there was no significant difference between mesiodistal and buccolingual surface. but in the marginal fit of IPS Empress and OPC crowns, there was significant difference between mesiodistal and buccolingual surface(p <0.01). 3. The marginal fit of four hinds of all-ceramic crowns was clinically acceptable.