Retention of core composites, glass ionomers, and cermets by a self-threading dentin pin: the influence of fracture toughness upon failure.
"Core composite" is available, and glass ionomer or materials based upon it (i.e., cermet, alloy/glass-ionomer mix) have potential for core-forming. Cores are retained routinely by pins, and the suitability of the retention of these materials by pins has been investigated. The maximum tensile force sustained by a particular self-threading dentin pin, selected for its retentive capability, was determined. Pins were embedded to a constant depth in cylindrical specimens. All specimens fractured at a force which correlated linearly with the fracture toughness of the embedding material. The glass-ionomer group of materials was inferior to the core composites, and doubts must surround the use of the former when retention of a core is dependent on dentin pins. The adhesive character of the glass-ionomer-based materials did not lead to failure forces higher than those predicted from their fracture toughnesses. When the data points for these materials were placed on a fracture force/fracture toughness plot together with data from earlier research, no point was displaced significantly from the straight line.
Lloyd
C H
CH
Dental School, University of Dundee, Scotland.
Butchart
D G
DG
D003188:Composite Resins; D003772:Dental Pins; D003776:Dental Porcelain; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements; D008422:Materials Testing
D003188:Composite Resins; D005899:Glass Ionomer Cements; D003776:Dental Porcelain