Effect of core material and restoration design on strength of endodontically treated bovine teeth: a laboratory study.
OBJECTIVE
The purpose of this study was to evaluate the fracture resistance of bovine teeth restored with one-piece cast core/crowns and no ferrule, compared to teeth restored with amalgam cores and full coverage crowns, with and without a dentine ferrule.


METHODS
Thirty bovine incisors were selected and modified to ensure all teeth had axial dentine walls of similar size. The teeth were then randomly allocated to one of the three groups: control group restored with amalgam core and cast crown without ferrule; ferrule group restored with amalgam core and cast crown with a 2-mm dentine ferrule; one-piece group restored with one-piece cast core/crown without ferrule. Each tooth was loaded to the point of fracture.


RESULTS
The mean load resisted by the control group, the ferrule group, and the one-piece group were 1092.5, 1843.5, and 1463.1 N, respectively. The mean load resisted by the ferrule group was significantly greater than the control group (p < 0.001) and the one-piece cast core/crown group (p= 0.04). The mean load resisted by the one-piece cast core/crown group was significantly greater than the control group (p= 0.04).


CONCLUSIONS
The maximum load resistance was significantly enhanced by a 2-mm ferrule compared with teeth with no ferrule and teeth restored with one-piece cast core/crowns. Teeth restored with one-piece cast core/crowns were significantly more resistant to loading than teeth restored with amalgam cores and crowns without a ferrule.
School of Dental Science, University of Melbourne, Victoria, Australia.
Simon
S
Hinckfuss
Peter R
PR
Wilson
D000818:Animals; D002417:Cattle; D002484:Cementation; D003442:Crowns; D003723:Dental Amalgam / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis / Q000295:instrumentation; D007180:Incisor; D011176:Post and Core Technique / Q000295:instrumentation; D011897:Random Allocation; D013314:Stress, Mechanical; D013499:Surface Properties; D014082:Tooth Fractures / Q000503:physiopathology; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D019553:Tooth, Nonvital / Q000628:therapy*; D015036:Zinc Phosphate Cement / Q000737:chemistry
D003764:Dental Materials; D015036:Zinc Phosphate Cement; D003723:Dental Amalgam