Comparative evaluation of retention of zirconia copings and cast metal copings cemented onto titanium abutments: An In vitro study

Abstract

Aim: This in vitro study was conducted to evaluate the retention of zirconia and cast metal copings luted to implant abutments using different luting agents. Subjects and Methods: Implant analogs were embedded in acrylic resin blocks, and titanium abutments were torqued at 35 N/cm onto the implant analogs. The samples were divided into two groups. Both Group A and B samples were then randomly divided into four groups each comprising specimens – Group 1, Group 2, Group 3, and Group 4. Copings were then cemented with resin modifies glass ionomer cement (GIC), GIC, zinc phosphate cement, and noneugenol zinc oxide cement, respectively. The cemented copings were subjected to tensile dislodgment forces using a crosshead speed of 5 mm/min. Results for the retention of the copings were statistically analyzed using factorial analysis of variance test. Results: Between the two copings, higher mean retention is recorded in zirconia compared to metal, and the difference between them is found to be statistically significant (P < 0.001). Among the four types of cements, higher mean retention was recorded with resin-modified GIC followed by zinc phosphate and GICs. The least retention strength was recorded with noneugenol zinc oxide cement. Conclusion: Definitive cements are recommended for luting single-unit implant-supported metal restorations. The provisional cement was found to be least retentive and may not be suitable for luting single-unit implant-supported restorations, whether for a zirconia or for a cast metal restoration.