Biomaterial Database

Initial dynamic viscoelasticity change of composites during light curing. 2010

Min-Ho Kim, and Sun-Hong Min, and Jack Ferracane, and In-bog Lee

Department of Conservative Dentistry and Dental Research Institute, Seoul National University, Yeongeon-Dong, Jongro-Gu, South Korea.

OBJECTIVE The aim of this study was to measure the initial dynamic viscoelastic modulus change of dental composites during light curing using a custom made oscillation rheometer. METHODS Six commercial universal hybrid resin composites: Z100 (Z1), Z250 (Z2), Z350 (Z3), DenFil (DF), Tetric Ceram (TC), and Clearfil AP-X (CF) were examined. A custom designed oscillation rheometer was made, which consisted of three parts: (1) an oscillatory shear strain induction unit, (2) a measuring unit of parallel plates made of glass rods, and (3) a stress measurement unit. For the measurement of the initial viscoelastic modulus change of composites during light curing as a function of time, a dynamic oscillatory shear test was undertaken at a frequency of 6Hz and strain amplitude of 0.00579rad for 10s. From the strain-stress curves, the complex shear modulus (G*), storage shear modulus (G'), loss shear modulus (G'') and loss tangent (tandelta), and the time to reach a G* of 10MPa were determined. The data were analyzed with one-way ANOVA and Tukey's post hoc test (alpha=0.05). RESULTS There were great differences in the development of viscoelasticity among materials. At 10s, the complex modulus G* of Z1 was the highest (563.7MPa), followed by CF, Z2, Z3, TC, and finally DF being the lowest (150.3MPa). The time to reach the G* of 10MPa ranged from 2.55s (Z1) to 4.06s (DF). The tandelta of the composites decreased with time as the polymerization reaction proceeded. CONCLUSIONS The initial modulus development of composites during curing plays a very important role in determining the polymerization shrinkage stress. The custom made oscillation rheometer was able to measure the very initial dynamic viscoelasticity change of several commercial composites during light curing; therefore, the instrument can be used to study the initial curing kinetics of newly developed composites.

UI	MeSH Term	Description	Entries
D008422	Materials Testing	The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.	Biocompatibility Testing,Biocompatible Materials Testing,Hemocompatibility Testing,Testing, Biocompatible Materials,Testing, Hemocompatible Materials,Hemocompatibility Testings,Hemocompatible Materials Testing,Materials Testing, Biocompatible,Materials Testing, Hemocompatible,Testing, Biocompatibility,Testing, Hemocompatibility,Testing, Materials,Testings, Biocompatibility
D009991	Oscillometry	The measurement of frequency or oscillation changes.	Oscillometries
D003188	Composite Resins	Synthetic resins, containing an inert filler, that are widely used in dentistry.	Composite Resin,Resin, Composite,Resins, Composite
D003799	Dental Stress Analysis	The description and measurement of the various factors that produce physical stress upon dental restorations, prostheses, or appliances, materials associated with them, or the natural oral structures.	Analyses, Dental Stress,Analysis, Dental Stress,Stress Analyses, Dental,Stress Analysis, Dental,Dental Stress Analyses
D004548	Elasticity	Resistance and recovery from distortion of shape.
D000704	Analysis of Variance	A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.	ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
D012212	Rheology	The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.	Flowmetry,Velocimetry,Velocimetries
D014783	Viscosity	The resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Viscosities
D055115	Light-Curing of Dental Adhesives	The hardening or polymerization of bonding agents (DENTAL CEMENTS) via exposure to light.	Dental Bonding, Light-Cured,Light-Curing of Dental Cements,Light-Curing of Dental Resins,Dental Adhesives Light-Curing,Dental Bonding, Light Cured,Dental Bondings, Light-Cured,Dental Cements Light-Curing,Dental Resins Light-Curings,Light Curing of Dental Adhesives,Light Curing of Dental Cements,Light Curing of Dental Resins,Light-Cured Dental Bonding,Light-Cured Dental Bondings
D018709	Statistics, Nonparametric	A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)	Kolmogorov-Smirnov Test,Kruskal-Wallis H Statistic,Mann-Whitney U Test,Rank-Sum Tests,Spearman Rank Correlation Coefficient,Wilcox Test,Wilcoxon Rank Test,Non-Parametric Statistics,Nonparametric Statistics,Statistics, Non-Parametric,Kolmogorov Smirnov Test,Mann Whitney U Test,Non Parametric Statistics,Rank Sum Tests,Rank Test, Wilcoxon,Rank-Sum Test,Statistics, Non Parametric,Test, Kolmogorov-Smirnov,Test, Mann-Whitney U,Test, Rank-Sum,Test, Wilcox,Test, Wilcoxon Rank,Tests, Rank-Sum,U Test, Mann-Whitney