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Statement of Problem.The biocompatibility of high-palladium alloy restorations has been of some concern due to the release of palladium into the oral environment and sensitivity reactions in patients. Purpose.This study measured the in vitro elemental release from a Pd-Cu-Ga alloy and a Pd-Ga alloy into a corrosion testing medium. Material and Methods.Both alloys were cast into 12-mm-diameter × 1-mm-thick disks, subjected to heat treatment that simulated porcelain firing cycles, polished to a 0.05-mm surface finish, and ultrasonically cleaned in ethanol. Two specimens of each alloy were immersed 3 times (at 7, 70, and 700 hours) in an aqueous lactic acid/NaCl solution used for in vitro corrosion testing and maintained at 37°C. The specimens were removed after each immersion time, and the elemental compositions of the solutions were analyzed with inductively coupled plasma-mass spectroscopy (ICP-MS). Elemental concentrations for the 2 alloys at each immersion time were compared with Student ttest (α=.05). Results.No significant differences in palladium release were found for the 7- and 70-hour solutions, but significant differences were found for the 700-hour solutions. Mean concentrations of palladium and gallium in the 700-hour solutions, expressed as mass per unit area of alloy surface, were 97 (Pd) and 46 (Ga) μg/cm2for the Pd-Cu-Ga alloy and 5 (Pd) and 18 (Ga) μg/cm2for the Pd-Ga alloy. Conclusion.Relative proportions of the elements in the solutions were consistent with the release of palladium and breakdown of microstructural phases found in the alloys. The results suggest that there may be a lower risk of adverse biological reactions with the Pd-Ga alloy than with the Pd-Cu-Ga alloy tested. (J Prosthet Dent 2002;87:80-5.)

Statement of problem.Crown fit is a prerequisite for long-term clinical success; however, crown distortion may occur during porcelain firing. The dimensional stability of some high-palladium alloys at high temperatures has been questioned. Purpose.The purpose of this study was to use a new method to measure the distortion of copings for metal-ceramic single units of selected high-palladium alloys with compositions representative of commercial alloys. Material and methods.Four high-palladium alloys containing copper and 3 containing no copper were tested. A palladium-silver alloy was included for comparison, and a gold-palladium alloy served as the control. By using reference points scribed on the margin, the mesiodistal and buccolingual margin diameters of identical copings were measured with a traveling microscope at 4 stages: as-cast, oxidized, after 2 simulated opaque porcelain firings, and after 2 simulated dentin porcelain firings. The margin distortions for the various specimen groups representing combinations of alloys, stages, and measurement diameters were compared with the use of 1-way analysis of variance and a multiple range test. Results.Most of the high-palladium alloys had high-temperature distortions that were not significantly different from those of the control alloy. The distortions occurred principally during the oxidation cycle. The effect of mesiodistal groove reinforcement on preventing distortion was not the same for all alloys. Conclusion.The results suggest that small observed distortions of these alloys will not produce clinical problems. Several laboratory techniques are available to counteract the distortions. (J Prosthet Dent 2001;85:133-40.)

PurposeThe purpose of this study was to assess the effect of different high‐palladium alloys on the resulting color of opaque porcelain. Three Pd‐Cu‐Ga alloys, Spartan Plus (S; Williams Dental Co/Division of Ivoclar North America, Amhest, NY), Liberty (B; J.F. Jelenko & Co, Armonk, NY), and Freedom Plus (F; J.F. Jelenko & Co); 4 Pd‐Ga alloys, Legacy (L; J.F. Jelenko & Co), IS 85 (I; Williams Dental Co), Protocol (P; Williams Dental Co), and Legacy XT (X; J.F. Jelenko & Co); and a Pd‐Ag alloy, Super Star (T; J.F. Jelenko & Co), were examined. The Au‐Pd alloy Olympia (O; J.F. Jelenko & Co) served as the control.

Statement of problem.Composite has been used to modify acrylic resin denture teeth. Purpose.This in vitro investigation examined the shear bond strengths between composite and autopolymerized acrylic resin bonded to acrylic resin denture teeth. Material and methods.The surface treatments used for the denture teeth included wetting with methyl methacrylate (MMA), vinylethyl methacrylate monomer (VEMA), unfilled liquid resin, composite bonding agent, and composite color modifier. Nonhydrated and hydrated denture tooth groups were included. A commercial composite was bonded to the denture teeth. The control group consisted of autopolymerized PMMA resin bonded to the acrylic resin denture teeth, and another group consisted of polyvinylethyl methacrylate bonded to acrylic resin denture teeth. The samples were thermocycled and tested in shear. Results.Acrylic resin denture teeth prewetted with MMA and treated with unfilled resin or a bonding agent had bond strength values comparable to the control group. VEMA was not as effective in promoting the bond. Composite color modifier did not produce a significantly weaker bond between the acrylic resin teeth and added composite. No prewetting of the teeth with MMA resulted in the lowest bond strength. Mean shear bond strengths for corresponding hydrated and non-hydrated groups were not significantly different. Conclusion.Bond strength of composite-to-acrylic resin denture teeth was comparable to the bond strength of autopolymerized acrylic resin. (J Prosthet Dent 1999;82:573-8.)

Objective. The purpose of this study was to use x-ray diffraction (XRD) to obtain new information about the oxide layers on four representative oxidized high-palladium alloys.