TOLERANCE-TEST OF 5 DIFFERENT TYPES OF CROWNS ON SINGLE-TOOTH IMPLANTS

Purpose: The main purpose of the present experimental study was to com pare five different types of crowns, cemented on implant abutments, re garding their capability to withstand loads. Materials and Methods: Th ree types of all-ceramic crowns, a gold-foil-reinforced porcelain crow n, and, as a control, a conventional metal ceramic crown were rested. Each crown was cemented onto an Astra Tech Single-Tooth implant. The f ive types of crowns, three of each type, and the titanium implants wer e subjected to loading in Lloyd test equipment until part of them was damaged, at which point the compression value was recorded and the def lection and bending moment were calculated. Comparisons were made on t he basis of these data. Results: The results showed that the all-ceram ic crowns fitted with a core should be able to withstand normally occu rring biting forces without difficulty. the foil crown was also judged to be acceptable, while the bending moment of the cast all-ceramic cr own without a Fore was considered unpredictable. The values for the me tal ceramic design were as predicted, ie, they were clearly the highes t in the study; the superior strength of metal ceramics should still b e taken into account when deciding between all-ceramic solutions and t he conventional metal ceramic crown. Conclusion: 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 in cisor and premolar regions), In-Ceram and AllCeram crowns seem to func tion satisfactorily on implants.