Effect of heating palladium-silver alloys on ceramic bond strength.

STATEMENT OF PROBLEM: The effects of different heat treatments on the internal oxidation and metal-ceramic bond in Pd-Ag alloys with different trace elements require further documentation. PURPOSE: The purpose of this in vitro study was to determine whether heat treatment affects the metal-ceramic bond strength of 2 Pd-Ag alloys containing different trace elements. MATERIAL AND METHODS: Thirteen cast specimens (25×3×0.5 mm) from each of 2 Pd-Ag alloy groups (W-1 and Argelite 61+3) were allocated to heat treatments before porcelain application: heating under reduced atmospheric pressure of 0.0014 MPa and 0.0026 MPa and heating under normal atmospheric pressure. Bond strengths were evaluated using a 3-point bending test according to ISO9693. Results were analyzed using 2-way ANOVA and Tukey HSD test (α=.05). Visual observation was used to determine the failure types of the fractured specimens. Scanning electron microscopy and energy dispersive spectroscopy were used to study morphologies, elemental compositions, and distributions in the specimens. RESULTS: The W-1 group had a mean bond strength significantly higher than that of Argelite 61+3 (P<.001). Heating under reduced atmospheric pressures of 0.0014 MPa and 0.0026 MPa resulted in similar bond strengths (P=.331), and both pressures had significantly higher bond strengths than that of heating under normal atmospheric pressure (P=.002, P<.001). Heating under different air pressures resulted in Pd-Ag alloys that contained either Sn or In and Ga, with various degrees of internal oxidation and different quantities of metallic nodules. CONCLUSIONS: Heating under reduced atmospheric pressure effectively improved the bond strength of the ceramic-to-Pd-Ag alloys.

Quantitative analysis of four types of primary glomeropathy by application of a decision forest to ultrasonic and laboratory characteristics.

The aim of this study was to apply a decision forest to analysis of the ultrasound characteristics and laboratory test indices of four types of primary glomerulopathy, and quantitative analysis of the four pathologic types using a combination of these two methods. The decision trees were derived from 41 clinical indices and 5 characteristic sonographic indices obtained for the left kidney. Fifty-six patients who had undergone ultrasound-guided renal biopsy were reviewed retrospectively, and on pathologic examination, the patients were diagnosed with primary glomerulopathy, which includes mesangial proliferative glomerulonephritis, membranous nephropathy, immunoglobulin A nephropathy and minimal change disease. In this study, eight characteristic indicators were correlated with pathologic type in the 56 cases of primary glomerulopathy. The order calculated by decision forests, from high to low, is proteinuria, length of kidney, serum creatinine, plasma albumin, area of kidney, total protein, thickness of renal parenchyma, 24-h urine protein. The glomerulopathy with the highest ++++ proteinuria is membranous nephropathy, which accounts for 39.2% (22/56) of the total sample; this was followed by minimal change disease, mesangial proliferative glomerulonephritis and immunoglobulin A nephropathy. On the basis of our analysis of 41 clinical indices, the key indices for quantitative analysis of primary glomerulonephritis are laboratory tests, and these include urine protein, serum creatinine, plasma albumin, total serum protein and 24-h urine protein. The three key sonographic features are measurement indices: renal length, renal area and renal parenchymal thickness. From the eight characteristic indicators, we observed that with respect to severity (from most severe to least severe), the four types of glomerulopathy are membranous nephropathy, minimal change disease, mesangial proliferative glomerulonephritis and immunoglobulin A nephropathy.