PubMed · 10605208
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R Suhonen. 1996. [Caustic ulcers].. https://pubmed.ncbi.nlm.nih.gov/10605208/
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OBJECTIVE: Aim of the present study was to evaluate the clinical suitability of the condensable metal-reinforced glass ionomer cement Hi-Dense in classes I and II cavities of primary molars. METHODS: Seventeen children received a total of fifty four Hi-Dense fillings (nineteen class I and thirty five class II). The restorations were clinically assessed at baseline, after one and after two years of clinical service according to modified USPHS codes and criteria. The restorations were replicated in each recall and representative samples were qualitatively analysed under a SEM. RESULTS: Over the observation period of two years, five restorations failed due to total retention loss, two fillings needed replacement because of persisting hypersensitivity, one filling was lost because of an unsuccessful endodontic treatment, and four restorations remained intact until natural exfoliation (Two year survival rate: 92% for Class I and 66% for Class II). The SEM analysis of surfaces and marginal areas exhibited an inferior adhesive performance primarily in proximal areas, whereas a negative step formation due to wear was frequently observed in occlusal parts. CONCLUSIONS: The results clearly indicate that the condensable, metal-reinforced GIC Hi-Dense reveals no enhanced performance and lifetime expectancy for class II restorations in primary molars when compared to other non-resin-modified GICs.
OBJECTIVES: This in vitro study on fluoride (F) release from conventional and metal-reinforced glass ionomer investigated the following: (1) the release of F in deionized water compared to artificial saliva, (2) the effect of various surface coatings on F release, (3) the uptake of released F by hydroxyapatite, (4) the expression of the release data in a mathematical model, (5) F content in the powders and set materials, and (6) surface morphology of varnished and resin-coated specimens. METHODS: Glass ionomer Ketac-Fil (KF), Fuji II (FJ), and Ketac-Silver (KS) were mixed according to the manufacturers' instructions, and prepared into specimens of 137.8 mm2 surface area. All three specimens were suspended in 50 ml of deionized water, artificial saliva, or aqueous solution of hydroxyapatite and submitted to constant agitation at 37 degrees C. In a separate experiment, the specimens were coated with varnish or light-cured bonding resin and tested for F release in solutions similar to those for uncoated specimens. The release of F occurred for 28 days. The concentration of F was measured with F-ion-specific electrode. RESULTS: All tested products showed a strong initial rate of F release which decreased with time until it reached a relatively steady rate after two weeks. The F released from KF and FJ was comparable in both pattern and magnitude. They released approximately four times more F than KS. In all cases, the release of F in artificial saliva was significantly (p < 0.001) less than in deionized water. Surface coating the specimens significantly reduced the F release ( p < 0.05 top < 0.001, depending on the product and type of coating). The inhibitory effect of coating markedly decreased with time. Resin coating reduced F release more than varnish in KF and KS, but not for FJ. Essentially, all F released in aqueous solution was taken up by the hydroxyapatite, with FJ ranking the highest in increasing hydroxyapatite F concentration. Over the 28 days, the quantities of F released from FJ, KF, and KS were, respectively, 3.8, 2.3, and 1.0% of the total F content in the specimens. The F concentration in the set KS was 53.9 and 72.5% of that found in KF and FJ, respectively. The release data as a function of time were best described by the power curve. Micromorphological examinations revealed remnants of surface coatings on specimens after 14 days storage in artificial saliva. CONCLUSIONS: Glass ionomer cements released significantly less F in artificial saliva than in deionized water. Surface coating the specimens substantially reduced F release. These clinically relevant factors were not considered by many in vitro release studies which overestimate the F availability from glass ionomers. A recall appointment 24 h after the placement of glass ionomer restoration should be given for surface finishing.
STATEMENT OF PROBLEM: New glass ionomer cements exhibit better mechanical properties than their older counterparts. However, there is concern about their use as a core material in post-and-core applications. PURPOSE: This in vitro study evaluated the fatigue resistance of 2 new glass ionomer cements, Shofu Hi-Dense and Fuji IX GP, and compared their mechanical behavior as a core material under masticatory load with a silver-reinforced glass ionomer (ESPE Ketac-Silver) and a silver amalgam (Cavex Avaloy LC). MATERIAL AND METHODS: A total of 100 commercial plastic teeth were divided into 4 groups of 25 specimens each. Titanium posts were placed in the prepared root canals, and cores were built up in amalgam, silver-reinforced glass ionomer cement, and the 2 new glass ionomer cements. The post-and-core specimens were prepared for full cast metal crowns, which were fabricated and cemented with glass ionomer cement. Twenty specimens from each group were placed in a mastication simulator and cyclically loaded with a 400 N force for 1.5 million cycles. The 5 remaining specimens were used as controls. The specimens were sectioned and observed macroscopically and microscopically to determine the number of defects (alterations) in each material. Observed defects were verified with the Kruskal-Wallis test, and the 4 core materials were ranked with the Tukey multiple comparisons test. RESULTS: The mean rank sum values of the defects were as follows: Cavex Avaloy LC Amalgam (16.75), Fuji IX GP (38.50), Shofu Hi-Dense (39.53), and ESPE Ketac-Silver (67.22). The amalgam alloy was significantly different (P< .05) from the others. CONCLUSION: Under the conditions of this study, the 2 new glass ionomer cements used as core materials showed a higher number of defects than amalgam. These results suggest that their fatigue resistance may be inadequate for post-and-core applications.