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The purpose of this study was to compare the fitness of the IPS Empress ceramic crowns according to margin type such as bevel, shoulder, rounded shoulder, shoulder with bevel, rounded shoulder with bevel and grooved bevel. After 10 experimental dies were constructed for each group, the IPS Empress ceramic crowns were fabricated on the dies, cemented with resin cement(Bistite resin cement, Tokuyama Soda Co. Ltd., Japan) and embeded in clear epoxy resin. Each specimen was sectioned with a low speed diamond saw in both the faciopalatal and the mesiodistal direction. The cement film thickness was measured with a measuring microscope. The obtained results were as follows : 1. The fitness at the external margin was good in the following order: rounded shoulder(28.99), shoulder with bevel(31.33), grooved bevel(31.79), rounded shoulder with bevel(34.65), bevel(35.02) and shoulder(35.08). However there is no significant statistical difference. 2. The fitness at the internal margin of bevel(25.75), rounded shoulder(31.24), shoulder with bevel(32.07) and rounded shoulder with bevel(34.45) was better than that of shoulder(47.98). 3. The fitness at the axial surface of bevel(26.58) was better than that of shoulder(49.59). 4. The fitness at the central fossa was good in the following order: shoulder with bevel(38.88), grooved bevel(40.46) rounded shoulder with shoulder(46.29), shoulder(48.91), bevel(49.47) and rounded bevel(52.07). However there is no significant statistical difference. 5. Overall fitness of bevel(29.71), rounded shoulder(32.49) and shoulder with bevel(34.47) was better than that of shoulder(44.73).
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