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 (ZrO2) copings to prepared crown. The aim of this in vitro study was to evaluate the ability of different luting agents to retain ZrO2 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. ZrO2 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 ZrO2 copings to prepared crown was not influenced by the types of luting agents.

Keywords

• luting agents
• retention
• thermocycling
• zirconium oxide coping