title: Single-crystalline ceramic whisker-reinforced carboxylic acid-resin composites with fluoride release.
abstract: Currently available glass-ionomer, resin-modified glass-ionomer, and compomer materials have relatively low strength and toughness and, therefore, are inadequate for use in large stress-bearing posterior restorations. In the present study, ceramic single-crystalline whiskers were mixed with fluorosilicate glass particles and used as fillers to reinforce experimental carboxylic acid-resin composites. The carboxylic acid was a monofunctional methacryloxyethyl phthalate (MEP). Five mass fractions of whisker/(whisker + fluorosilicate glass), and corresponding resin (resin + MEP), were evaluated. Four control materials were also tested for comparison: a glass ionomer, a resin-modified glass ionomer, a compomer, and a hybrid composite resin. Flexural specimens were fabricated to measure the flexural strength, elastic modulus, and work-of-fracture (an indication of toughness). Fluoride release was measured by using a fluoride ion selective electrode. The properties of whisker composites depended on the whisker/(whisker + fluorosilicate glass) mass fraction. At a mass fraction of 0.8, the whisker composite had a flexural strength in MPa (mean +/- sd; n = 6) of 150 +/- 16, significantly higher than that of a glass ionomer (15 +/- 7) or a compomer control (89 +/- 18) (Tukey's multiple comparison test; family confidence coefficient = 0.95). Depending on the ratio of whisker:fluorosilicate glass, the whisker composites had a cumulative fluoride release up to 60% of that of a traditional glass ionomer. To conclude, combining ceramic whiskers and fluorosilicate glass in a carboxylic acid-resin matrix can result in fluoride-releasing composites with significantly improved mechanical properties.
authors.affiliation: Paffenbarger Research Center, American Dental Association Health Foundation, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
authors.forename: H H
authors.initials: HH
authors.lastname: Xu
authors.forename: F C
authors.initials: FC
authors.lastname: Eichmiller
authors.forename: J M
authors.initials: JM
authors.lastname: Antonucci
authors.forename: G M
authors.initials: GM
authors.lastname: Flaim
mesh_terms: D000704:Analysis of Variance; D002327:Cariostatic Agents / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D020770:Compomers / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D016001:Confidence Intervals; D003461:Crystallography; D003764:Dental Materials / Q000737:chemistry*; D004058:Diffusion; D004548:Elasticity; D005459:Fluorides / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D017736:Ion-Selective Electrodes; D008422:Materials Testing; D010795:Phthalic Acids / Q000737:chemistry*; D018583:Pliability; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012824:Silicic Acid / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry*; D013223:Statistics as Topic; D013314:Stress, Mechanical
chemical_list: D002327:Cariostatic Agents; D020770:Compomers; D003188:Composite Resins; D003764:Dental Materials; D005899:Glass Ionomer Cements; D010795:Phthalic Acids; D019279:Resin Cements; D012821:Silanes; D017655:Silicon Compounds; D012824:Silicic Acid; C035291:hexafluorosilicic acid; C032279:phthalic acid; D005459:Fluorides; C032734:silicon nitride