Tolerance test of five different types of crowns on single-tooth implants.
OBJECTIVE
The main purpose of the present experimental study was to compare five different types of crowns, cemented on implant abutments, regarding their capability to withstand loads.


METHODS
Three types of all-ceramic crowns, a gold-foil-reinforced porcelain crown, and, as a control, a conventional metal ceramic crown were tested. Each crown was cemented onto an Astra Tech Single-Tooth implant. The five types of crowns, three of each type, and the titanium implants were subjected to loading in Lloyd test equipment until part of them was damaged, at which point the compression value was recorded and the deflection and bending moment were calculated. Comparisons were made on the basis of these data.


RESULTS
The results showed that the all-ceramic crowns fitted with a core should be able to withstand normally occurring biting forces without difficulty. The foil crown was also judged to be acceptable, while the bending moment of the cast call-ceramic crown without a core was considered unpredictable. The values for the metal ceramic design were as predicted, ie, they were clearly the highest in the study; the superior strength of metal ceramics should still be taken into account when deciding between all-ceramic solutions and the conventional metal ceramic crown.


CONCLUSIONS
It was concluded that all-ceramic crowns are weaker than conventional metal ceramic crowns: however, based on estimated maximum clinical loading (370 N in the incisor and premolar regions), In-Cream and AllCeram crowns seem to function satisfactorily on implants.
Erneklint
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C
Department of Prosthetic Dentistry and Technology, Faculty of Odontology, Göteborg University, Sweden.
Odman
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P
Ortengren
U
U
Rasmusson
L
L
D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D003442:Crowns; D019250:Dental Implants, Single-Tooth; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D006047:Gold Alloys / Q000737:chemistry; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry; D018583:Pliability; D013718:Tensile Strength
C105314:AllCeram; D000538:Aluminum Silicates; D006047:Gold Alloys; C075815:IPS-Empress ceramic; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; C070870:In-Ceram; D000537:Aluminum Oxide