PubMed · 12522859
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K F Leinfelder. 2000. Developments in indirect resin composite materials.. https://pubmed.ncbi.nlm.nih.gov/12522859/
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This study focuses on the electrolytic regeneration of spent chromium plating solutions. These solutions contain a significant amount of chromium and a lesser amount of other heavy metals, which makes them a significant environmental concern and an obvious target for recycling and reuse. The type of separator used is extremely critical to the performance of the process because they are the major resistance in the transport-related impurity (Cu(II), Ni(II), and Fe(III)) removals from contaminated chromic acid solutions. A Nafion 117 membrane and a ceramic diaphragm separator traditionally used in the industry were tested for comparison. It was found that the mobilities of Cu(II) and Ni(II) were similar and higher than that of Fe(III) using both separators. The mobility of each cation was smaller in the Nafion membrane than in the ceramic diaphragm. The measured conductivity of the ceramic diaphragm was slightly higher than that of Nafion membrane. However, the Nafion membrane was much thinner than the ceramic diaphragm resulting in the system using the Nafion membrane having higher impurity removal rates than the system using the ceramic diaphragm. The removal rates were approximately equal for Cu(II) and Ni(II) and lowest for Fe(III). Both current and initial concentration affected the removal rates of the impurities. Modeling results indicated that a system using a Nafion separator and a small catholyte/anolyte volume ratio was better than a system using a ceramic separator for removing impurities from concentrated plating solutions if the impurities transported into the catholyte are deposited or precipitated.
BACKGROUND: In recent decades ceramic inlays have been used with the increasing requirements from patients for tooth-coloured restorations in posterior teeth. Ceramic inlays can offer an excellent appearance, however, their long-term prognosis is uncertain, as only a few studies have reported the long-term clinical performance of these restorations. OBJECTIVES: To compare the effectiveness of ceramic inlays in posterior teeth with other posterior restorations. SEARCH STRATEGY: We conducted an electronic search of the Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials ( The Cochrane Library Issue 1, 2002), MEDLINE, and EMBASE from 1990 to 2001. Handsearching included relevant journals and bibliographies of all relevant papers and review articles from 1990 up to 2001. In addition, we contacted experts and companies conducting clinical research on ceramic restorations to find other trials or unpublished materials or to clarify ambiguous or missing data. SELECTION CRITERIA: Randomized controlled trials, in which the longevity of ceramic inlays is compared with those of other posterior restorations. DATA COLLECTION AND ANALYSIS: Screening of possible studies and data extraction were independently conducted by two reviewers (MH and AY) using a specially designed chart. Authors of studies were contacted for additional information. The methodological quality of studies was assessed in duplicate using individual components. The Cochrane Oral Health Group statistical guidelines were followed and the results expressed as Odds Ratio (OR) and 95% confidence interval for dichotomous outcomes. MAIN RESULTS: Two studies fulfilled the criteria to be included in the review. However, one of them was later excluded from the review, as the study design was not clearly described. The remaining, included study, evaluated the clinical performance of 60 ceramic inlays and 20 gold inlays for five years. Seven of the 60 ceramic inlays and two of the 20 gold inlays failed at five-year review. No ceramic inlays resulted in postoperative pain/discomfort after the treatment, however, one gold inlay did. The power of the included study was not great enough to detect an important difference in longevity and postoperative pain/discomfort between ceramic and gold inlays. REVIEWER'S CONCLUSIONS: There is no strong evidence available to support any differences in the clinical performance of ceramic inlays and other posterior restorations. There is a limited number of well-designed clinical trials within this research area. Greater attention to the design and reporting of studies should be given to improve the study quality of ceramic restoration trials.
ZrO(2) (4% CeO(2)) and ZrO(2) (3% Y(2)O(3)) coatings were deposited on titanium (Ti) and CoCrMo implants using plasma spraying and the adhesive, morphological and structural properties of the plasma-sprayed coatings were evaluated. Characterization of these coatings was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), surface roughness, hardness, and adhesive strength. XRD patterns showed that both the coatings appeared to be primitive tetragonal phase. SEM observations showed that both the ZrO(2) coatings appeared to be rough, porous and melted. The cross-section surface morphology of the coatings, coating-substrate interfaces and substrates without acid etching was very dense and smooth. After acid etching, as compared to the dense ZrO(2) coating-CoCrMo substrate interfaces, the thin gaps appeared within the ZrO(2) coating-Ti substrate interfaces. It is suggested that plasma spraying probably formed an amorphous Ti layer in the coating-Ti substrate interface that can be removed by acid etching. The average surface roughness of ZrO(2) (3% Y(2)O(3)) and ZrO(2) (4% CeO(2)) coatings was correlated to the starting powder size and substrates. No significant difference between the hardness of all coatings and substrates was observed. The adhesive strengths of ZrO(2) (4% CeO(2)) coating to Ti and CoCrMo substrates were higher than 68MPa and significantly greater than that of ZrO(2) (3% Y(2)O(3)) coatings.