Abstract
The aim of this in vitro study was to investigate three different cements for their suitability to provide semi-permanent cementation, and to compare the retention forces of implant-supported single crowns (SC) and three-unit fixed dental prostheses (FDP) luted with these cements. Twenty-four methacrylate models were supplied with three implants/abutments each to simulate the condition of SCs/FDPs. Cobalt-chromium frameworks were fabricated, sandblasted (Al2O3/50 µm/0.2 MPa) then cemented with glass-ionomer (KTC), polycarboxylate (DUR) or self-adhesive resin cement (RXU). Specimens were stored in a saline-solution (NaCl/37 °C/24 h) or subjected to thermocycling. A universal testing machine and a pull-off device were used to remove the copings. The multi-factor ANOVA showed that the retention force differed significantly among all cements for the SCs after NaCl storage (p < 0.05). Mean retention forces (in Newtons) after NaCl storage were (SCs/FDPs): KTC 170/352, DUR 409/406, RXU 265/426, and after thermocycling (SCs/FDPs): KTC 156/262, DUR 306/380, RXU 494/508. FDPs showed higher retention values in comparison to SCs. For SCs, artificial aging with thermocycling resulted in a significant retention increase for RXU, whereas the retention of KTC and DUR was decreased. Glass ionomer can be used as a semi-permanent cement for both SCs and FDPs. Polycarboxylate cement is considered semi-permanent after one year of aging.
Highlights
The use of dental implants has enriched the treatment options in prosthetic dentistry and is highly beneficial for the improvement of quality of life especially for edentulous [1], as well as for partially edentulous patients [2]
High survival rates have been reported for implant-supported restorations (97.2% after 5 years and 95.2% after 10 years); the prevalence of peri-implantitis 2 years after placement was 34% and 21%
A vertical rotation lock with a length of 5 mm and a depth of 0.5 mm was milled into the abutment using a hard alloy bur (Figure 1b)
Summary
The use of dental implants has enriched the treatment options in prosthetic dentistry and is highly beneficial for the improvement of quality of life especially for edentulous [1], as well as for partially edentulous patients [2]. High survival rates have been reported for implant-supported restorations (97.2% after 5 years and 95.2% after 10 years); the prevalence of peri-implantitis 2 years after placement was 34% (patient level) and 21%. (implant level) based on recent studies [3,4] These rates represent a major dental health burden. For this reason, ease of retrievability of prosthetic restorations is necessary, which is given in removable restorations, but difficult to some extent in fixed dental restorations. Implant-supported fixed prosthetic restorations can be either cemented or screw-retained and according to recently published systematic reviews, there seems to be no significant difference between both, in terms of implant and restoration survival [5,6,7,8].
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