Effect of Luting Cements on the strength of Procera copings

Objectives: To investigate the effect of conventional and resin luting cements on the fracture strength of Procera AllCeram copings (Nobel Biocare, Goteborg, Sweden). Methods: Six metal dies were duplicated from the prepared maxillary first premolar tooth using non-precious metal alloy (Wiron 99). Thirty Procera copings with 0.6 mm thickness were manufactured using CAD/CAM technology. Three types of luting cements were used; zinc phosphate cement Elite (GC Corporation, Tokyo, Japan), glass-ionomer cement Fuji I (GC Corporation, Tokyo, Japan) and dual-cured composite resin cement Panavia F (Kuraray Medical Inc., Okayama, Japan). Ten copings were cemented with each type. Two master dies were used for each group and each of them was used to lute five copings. All copings were cemented as per manufacturer's instructions and stored for 24 hours in distilled water at 37ºC. The copings were seated with 5 kg of force for 10 minutes. Each coping was subjected to a compressive load until failure at a crosshead speed of 1mm/minute. The fractured copings were examined using Scanning Electron Microscope (SEM). Results: Statistical analysis carried out using ANOVA and Duncan's multiple range test revealed significant difference between the three groups (P<.001). The mean fracture strength of Procera copings cemented with Elite, Fuji I and Panavia F were 1091.9 N, 784.8 N and 1953.5 N respectively. The Procera core examined by SEM had very little porosity with the retention of resin cement only on the intaglio surface of Procera copings. Conclusions: The fracture resistance of Procera AllCeram copings was significantly affected by the luting agent used. This study was supported by Vote F (F0155/2005A); University of Malaya, Kuala Lumpur, Malaysia.