George D. Quinn

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OBJECTIVES Presentation of a methodological approach using stereo and scanning electron microscope examination for the failure analysis of an alumina all-ceramic premolar crown (Procera AllCeram). METHODS The recovered part of a fractured Procera alumina crown was examined utilizing first a stereomicroscope and second a scanning electron microscope (SEM).(More)
OBJECTIVES Develop fractographic techniques to perform failure analyses of three ceramic whole-crown clinical failures. METHODS Three clinical whole-crown failures of different ceramic material systems were studied. The systems included appropriate veneers applied to core materials of cold isostatically pressed alumina, injection molded(More)
OBJECTIVES Determination of material and fractographic properties of a dental indirect resin composite material. METHODS A resin composite (Paradigm, 3M-ESPE, MN) was characterized by strength, static elastic modulus, Knoop hardness, fracture toughness and edge toughness. Fractographic analyses of the broken bar surfaces was accomplished with a(More)
OBJECTIVES To demonstrate the effectiveness of in vivo replicas of fractured ceramic surfaces for descriptive fractography as applied to the analysis of clinical failures. METHODS The fracture surface topography of partially failed veneering ceramic of a Procera Alumina molar and an In-Ceram Zirconia premolar were examined utilizing gold-coated epoxy(More)
OBJECTIVES To investigate the chipping resistance of veneered zirconia specimens and compare it to the chipping resistance of porcelain fused to metal (PFM) specimens. METHODS Veneered zirconia and PFM bar specimens were prepared in clinically relevant thicknesses. The specimen edges were chipped with different magnitude forces, producing chips of various(More)
PURPOSE To educate dental academic staff and clinicians on the application of descriptive (qualitative) fractography for analyses of clinical and laboratory failures of brittle materials such as glass and ceramic. MATERIALS AND METHODS The fracture surface topography of failed glass, glass fiber-reinforced composite, and ceramic restorations (Procera,(More)
OBJECTIVES Fractographic analysis of indentation cracks is performed following flexure testing as part of the ASTM (1999) standard for fracture toughness, KIc, determination in advanced ceramics. This method depends on the conduciveness of the material towards fractographic interpretation. The purpose of this study was to evaluate the use of fractography in(More)
Veneering ceramics designed to be used with modern zirconia framework restorations have been reported to fracture occasionally in vivo. The fracture toughness of such veneering ceramics was measured and compared to that of conventional feldspathic porcelain veneering ceramics for metal framework restorations. The fracture toughness of the leucite free(More)
OBJECTIVES To review the history, theory and current applications of Weibull analyses sufficient to make informed decisions regarding practical use of the analysis in dental material strength testing. DATA References are made to examples in the engineering and dental literature, but this paper also includes illustrative analyses of Weibull plots,(More)
Fractographic analysis of clinically failed dental ceramics can provide insights as to the failure origin and related mechanisms. One anterior 6-unit all-ceramic zirconia fixed partial denture (FPD) (Cercon) has been clinically recovered and examined using qualitative fractography. The purpose was to identify the fracture origin and to state the reasons for(More)