Marginal Gap Discrepancies in Metal Porcelain Crowns with Co-Cr Coping before and after Porcelain Firing

摘要

Metal porcelain crown is still commonly used because of the strength of the metal and the estheticof the porcelain. Base metal alloys that commonly used as copings of metal porcelain crowns arenickel-chromium and cobalt-chromium. Cobalt-chromium is preferable because it has betterbiocompatibility for patients that have allergies to nickel. The marginal gap is one of the importantfactors that determine the success of a restoration. This study aims to measure the marginal gapbetween the cervical margin of the prepared tooth and the cervical margin of a metal porcelaincrown with Co-Cr coping before and after porcelain firing. Sixteen teeth that needed to be treatedwith metal porcelain crowns were examined at the Dental Teaching Hospital Faculty of Dentistry,Universitas Indonesia, by using a consecutive sampling method. The marginal gaps of metalporcelain crowns with Co-Cr coping before and after porcelain firing were measured with theimpression replica technique at four surfaces (buccal, mesial, distal, and palatal) using an opticmicroscope (Olympus BX41. Statistical analyses revealed a significant difference between themarginal gaps of metal porcelain crowns before and after porcelain firing on all surfaces (p<0.05),which was clinically acceptable.