Retention force of secondary crowns to copings after temporary cementation: the effect of crown material and luting agent.
Tooth-implant supported restorations can be temporarily cemented if the natural abutments are protected by permanently cemented copings. This in vitro study investigated the retention forces of pure titanium crowns to milled titanium alloy copings and of cobalt-chromium crowns to copings made of electroplated gold after cementation with different luting agents. Five specimens per group were cemented with acrylic-urethane cement (inner crown surface preisolated with petroleum jelly) and provisional zinc oxide cement. The retention was measured using a universal testing machine and a dental device for crown removal. The differences between groups were compared using analysis of variance. The pull-off forces for the cobalt-chromium secondary crowns cemented on gold copings using zinc oxide cement were significantly higher (mean=144.5 N) than the other crown-cement combinations (32.2-54.4 N), which showed no significant differences in the retention force. The impulse number and magnitude of the dental device was usually low and showed no substantial differences between the crown-cement combinations. It can be concluded that the results of the clinical removal method for prostheses differ from the results of the pull-off test. The question which luting agent is the better choice for retrievable restorations remains unanswered without further clinical and laboratory studies.
Department of Prosthodontics, Gerodontology and Biomaterials, Center of Oral Health, University of Greifswald, Greifswald, Germany.
Torsten
T
Mundt
Friedhelm
F
Heinemann
Gudrun
G
Golecki
Christian
C
Schwahn
Reiner
R
Biffar
D000269:Adhesives; D001641:Bicuspid / Q000737:chemistry*; D002484:Cementation / Q000379:methods*; D003442:Crowns; D003738:Dental Cements / Q000737:chemistry*; D003794:Dental Restoration, Temporary / Q000295:instrumentation*; D006801:Humans; D008422:Materials Testing; D013314:Stress, Mechanical
D000269:Adhesives; D003738:Dental Cements