An in-vitro assessment of fracture resistance of five porcelain crown systems
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Abstract
A total of forty five crowns of five different porcelain systems (Porcelain-fused-to-metal, Porcelain jacket, Dicor, Cerestore and Renaissance) were fabricated to uniform dimension and shape on identical metal dies by different sources (Manufacturers, commercial laboratories, and investigator). The crowns were permanently cemented to their dies and subjected to shear forces directed at a 130 degree angle to their incisal edge in an Instron testing machine. The fracture patterns were observed microscopically. Mean fracturing loads for the five different crowns systems were calculated and compared.
The recorded mean fracture loads (in lbs) were: Group 1 (porcelain-fused-to-metal fabricated by manufacturer), 132 ±5; Group 2 (porcelain jacket fabricated by commercial laboratory), 42 ±4; Group 3 (Dicor crowns fabricated by commercial laborato ry), 79 ±5; Group 4 (Dicor crowns fabricated by manufacturer), 87 ±9; Group 5 (Dicor crowns at 1.5mm thickness fabricated by manufacturer), 98 ±6; manufacturer), 92 ±4; Group 6 (Cerestore crowns fabricated by Group 7 (Cerestore crowns fabricated by investigator), 68 ±15; group 8 (Renaissance crowns fabricated by manufacturer), 60 ±7; and Group 9 (Renaissance crowns fabricated by investigator), 27 ±4;
The normal ranking of the results (i.e. p.f.m.- strong, p.j. - weak) and the fine discrimination between similar groups suggest that this testing modality has merit.
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Colored photographs included.
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1986 (Prosthodontics)
Bibliography : leaves 67-69.
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1986 (Prosthodontics)
Bibliography : leaves 67-69.
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