Weakening the bond strength of luting agents could be a goal in implant retained prosthetics

Abstract

Aim of the study: The current study was conducted to provide a simple practical technique to relatively weaken the bond strength of E.max Press copings retained to zirconia implant abutment models. This technique should facilitate crown retrieval from onto implant abutments without affecting the integrity of the ceramic crowns, abutment or the implant’s integration, yet, the crown is still well retained during service.Materials and methods: Twenty four zirconia implant abutment models were specially fabricated for the current study, to which 24 e.max press copings were cemented. According to the cementation technique, the samples were divided into four groups, 6 samples each. In Gp A, copings were cemented with a temporary resin luting cement without any surface treatment to the abutment models or the intaglio surfaces of the copings. In Gp B, abutments’ surfaces as well as intaglio surfaces of the copings were treated according to manufacturers’ instructions before cementation with permanent resin luting cement. In Gp C, abutments’ surfaces were coated with a single coat of fresh whole saliva before cementing copings with the permanent resin luting cement. In Gp D, same as in Gp C with replacement of saliva with single coat of glycerin. All assemblies were then subjected to aging through thermocycling for 5000 cycles.All assemblies were then tested for retention of coping cemented to the zirconia implant abutment models and failure surfaces were then examined by stereomicroscope to detect the mode of failure.Results: All samples in Gp A failed before any mechanical testing. Gp C reviled insignificant bond strength results compared to Gps B and D. However, Gp D showed significant reduction in bond strength compared to Gp B.Conclusions: Glycerin coating of zirconia implant abutments before use of permanent resin luting cement would be a good technique to retain crown in place for longer time, yet still liable to easy retrieval.