Evaluation of bond strength of metal substructures prepared by different production techniques and porcelaines

Tooth loss causes functional and aesthetic disadvantages in humans and needs to be treated prosthetically. Metal ceramic restorations are used for prosthetic treatment for a long time in tooth deficiencies. With increasing use of technology and aesthetic demands, metal ceramic restorations are becoming frequently used treatment options for complicated cases. The primary reason for the using of porcelain for making crowns and bridge prostheses is that they are aesthetically and biologically compatible with natural teeth. Metal alloys are used as a rigid base in order to prevent breakage of the non-resistant ceramic by chewing forces in the mouth. Different metal alloys can be used for manufacturing of restorations. Formerly gold alloys were preferred for making restorations, but today cobalt-chromium, titanium, and zircon can be preferred. For the clinical success of restorations it is important that there is a strong connection between the metal substructure and the porcelain. Metal alloys with different metal contents are made with casting method for many years. In recent years, technology of producing dental metal alloys have improved with the dental technological developments and nowadays the use of CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) and Laser Sinter technology in manufacturing of metal alloys has become popular. CAD/CAM and Laser Sinter manufacturing technique is firstly the digital dimension of the toothless area is taken. Then infrastructure of dental restoration is digitally designed with computer and the digital design is produced with metal alloy. There are many different brands of porcelains to be processed on metal and different brands are used in dental laboratories. Although there are studies in the literature about the connection between metal and porcelains, there is not much research on the connection of metals produced with new CAD/CAM and Laser Sinter techniques and porcelains in different brands. It is necessary to investigate the comparision of the adhesion of the different metal production techniques and the porcelain in different brands. In this study, bonding strengths of Co-Cr metal infrastructure materials prepared with casting, milling and laser sinter production methods and porcelains with three different brands (Noritake Ex3, Ceramco3, Vita VMK Master) were mechanically tested. For this purpose, three different porcelain brands were builded to Co-Cr metal samples (n: 12) and after 5000 thermal cycles shear test applied. As a result, no significant difference was found between bond strengths of different metal production techniques (p>0,05). It has been found that there is a significant difference between the bond strengths of different brand porcelains and metal specimens (Vita VMK Master> Ceramco3> Noritake Ex3) (p<0,05). Porcelain brands showed similar performance in all metal groups, no significant difference was found (p>0,05).