Retention of zirconium oxide copings using different types of luting agents

Abstract Background/purpose There is limited information in the literature regarding the effect of different luting agents on the bond strength of zirconium oxide (ZrO 2 ) copings to prepared crown. The aim of this in vitro study was to evaluate the ability of different luting agents to retain ZrO 2 copings on prepared crowns under laboratory conditions. Materials and methods Forty-two extracted human maxillary first premolars were prepared with a flat occlusal surface, and rounded line angles, a 5° taper and approximately 3-mm occluso-gingival height. ZrO 2 copings were manufactured with buccal and lingual projections to assist removal of the crown after cementation. All copings were airborne-particle abraded with 50 μm aluminum oxide for 15 seconds. The specimens were randomly distributed into three equal groups ( n  = 14) and cemented with one of three luting agents: resin-modified glass–ionomer cement, self-adhesive resin cement, and adhesive resin cement. The cemented specimens were thermocycled (3000 cycles, 5–55°C), and then removed along the path of insertion using a universal testing machine at 0.5 mm/minute. Statistical analyses of the data were performed using one-way ANOVA (α = 0.05). Results Mean copings bond strengths were 440 N, 416 N, and 360 N for resin-modified glass–ionomer cement, self-adhesive resin cement, and adhesive resin cement, respectively. There was no statistically significant difference in mean crown retention between the three cementation groups. Conclusion Retention of ZrO 2 copings to prepared crown was not influenced by the types of luting agents.