Cement selection for fixing implant restorations

Introduction When intraocclusal space is long enough, and patient has high aesthetic demands, cementing implant restoration is the proper choice. The aim of this study was to assess retentive forces of different cements used for fixing restoration to implant abutment. Material and method the separation forces were measured between restorations and abutments that were screw retained to the implant replica. The restorations were casted from Co-Cr-Mo alloy. They were cemented to abutments with five different types of cements (composite resin, glass-ionomer, zinc-polycarboxylate, zinc-phosphate and temporary cement). Each cement represented one group and each group included seven samples. Results Composite resin, glass-ionomer and zinc-polycarboxylate cements showed similar values of retentive forces (256-275 N), while zinc-phosphate cements had slightly lower value (174 N). Temporary cement showed significantly lower value of retentive force (59N). All cements for permanent bonding showed almost the same separation nature. By slow loading, the stress develops, leading to slightly stretched cement and as a consequence, sudden break of cement. Temporary cements also develop stress when slowly loaded, which firstly leads to stretching of cement, and then slight detachment from the implant replica. Conclusion Temporary cement has the lowest retentive force and is suitable for temporary bonding. Composite resin, glass-ionomer, zinc-polycarboxylate and zinc-phosphate cements have high retentive force, and they can be used for permanent cementation of restoration to abutment. Due to the high values of separation force, and other positive characteristics, composite resin should be cement of choice for bonding restorations to implant abutments.