Retrievability of implant-supported zirconia restorations cemented on zirconia abutments

Publication date: Available online 25 May 2018
Source:The Journal of Prosthetic Dentistry
Author(s): Andrea Lennartz, Andrea Dohmen, Shaza Bishti, Horst Fischer, Stefan Wolfart
Statement of problemRetrievability of implant-supported restorations is important. Data are lacking for cemented zirconia crowns on zirconia abutments.PurposeThe purpose of this in vitro study was to investigate the influence of different cements and marginal discrepancy on the retrievability of implant-supported zirconia crowns. Furthermore, the influence of thermocycling on retrievability was evaluated.Material and methodsThirty tapered Camlog zirconia abutments (6-degree taper, 6×4.3 mm) were used. Thirty zirconia crowns with 3 different marginal cementation discrepancies (70, 130, 190 μm) were fabricated by using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. Five cements for interim or semidefinitive cementation were used: eugenol-free zinc oxide (Freegenol) and acrylurethane (ImProv) and 3 different composite resin cements (X-Pand Implant, Dyna Implant, Telio CS Cem Implant). Specimens underwent either 3-day storage in sodium chloride or thermocycling (10 000 cycles). Crowns were removed by using a universal testing machine (UTM) and a clinical removal device. Data were analyzed using 1-way ANOVA and the Scheffé test (α=.05).ResultsThermocycling decreased the retention force significantly (P<.001). Marginal discrepancy (70 to 190 μm) was not significantly influential on retrievability (P>.05). Therefore, groups were pooled according to the factor of marginal discrepancy. The mean retention force using the UTM after 3-day storage and thermocycling was as follows: Freegenol, 235 ±42 N (thermocycling, 29 ±9 N); Improv, 110 ±50 N (thermocycling, 35 ±38 N); Telio CS, 104 ±17 N (thermocycling, 6 ±10 N); Dyna implant, 61 ±17 N (thermocycling, 1 ±1 N); and X-Pand, 50 ±16 N (thermocycling, 2 ±2 N).ConclusionsRetention forces of the tested cements were significantly different and decreased considerably after thermocycling. Marginal cementation discrepancy between 70 and 190 μm did not influence retrievability.



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