Fracture mechanics analysis of the dentine-luting cement interface.
The objectives of this study were to determine the fracture toughness of adhesive interfaces between dentine and clinically relevant, thin layers of dental luting cements. Cements tested included a conventional glass-ionomer, F (Fuji 1), a resin-modified glass-ionomer, FP (Fuji Plus) and a compomer cement, D (DyractCem). Ten miniature short-bar chevron notch specimens were manufactured for each cement, each comprising a 40 microm thick chevron of lute, between two 1.5 mm thick blocks of bovine dentine, encased in resin composite. The interfacial K(IC) results (MN/m3/2) were median (range): F; 0.152 (0.14-0.16), FP; 0.306 (0.27-0.37), D; 0.351 (0.31-0.37). Non-parametric statistical analysis showed that the fracture toughness of F was significantly lower (p <0.05) than those of FP or D, and all were significantly lower than values for monolithic cement specimens. Scanning electron microscopy of the specimens suggested crack propagation along the interface. However, energy dispersive X-ray analysis indicated that failure was cohesive within the cement. It is concluded that the fracture toughness of luting cement was lowered by cement-dentine interactions.
Ryan
A K
AK
School of Mechanical and Manufacturing Engineering, The Queen's University of Belfast, UK.
Mitchell
C A
CA
Orr
J F
JF
D000818:Animals; D002417:Cattle; D020770:Compomers; D003738:Dental Cements / Q000737:chemistry*; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis / Q000379:methods*; D003804:Dentin / Q000293:injuries / Q000503:physiopathology* / Q000648:ultrastructure; D005899:Glass Ionomer Cements / Q000737:chemistry; D006244:Hardness; D066298:In Vitro Techniques; D007180:Incisor / Q000293:injuries* / Q000503:physiopathology; D008422:Materials Testing / Q000295:instrumentation* / Q000379:methods*; D008689:Methacrylates / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014082:Tooth Fractures / Q000503:physiopathology
D020770:Compomers; D003738:Dental Cements; C088486:Dyract; C113301:FujiPlus; D005899:Glass Ionomer Cements; D008689:Methacrylates; D019279:Resin Cements; D017640:Silicates; C084541:Fuji glass-ionomer lining cement