Multiple correlations of material parameters of light-cured dental composites (original) (raw)

A material model for internal stress of dental composites caused by the curing process

Dental Materials, 2009

d e n t a l m a t e r i a l s 2 5 ( 2 0 0 9 ) 331-338 a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . i n t l . e l s e v i e r h e a l t h . c o m / j o u r n a l s / d e m a Viscoelasticity Dental composites Curing shrinkage Material model a b s t r a c t Objective. To compare the build-up of internal stresses in four different dental composites (Venus, Tetric Ceram, Ceram X mono and Filtek Supreme) during the curing reaction, based on the results of a former paper on polymerization kinetics, and to characterize the developing mechanical behavior for different modes of activation using experimental methods and simulation tools. Methods. A four-parameter viscoelastic model combined with a curing model and a kinetic model was developed to simulate the mechanical behavior in three dimensions using the finite element software ABAQUS. In order to study the influence of slow polymerization behavior on the mechanical properties, the length of the activation period was doubled at half intensity of the curing light.

Polymerization Shrinkage, Hygroscopic Expansion, Elastic Modulus and Degree of Conversion of Different Composites for Dental Application

Journal of Composites Science, 2021

Objectives: To characterize the mechanical properties of different resin-composites for dental application. Methods: Thirteen universal dentin shade composites (n = 10) from different manufacturers were evaluated (4 Seasons, Grandio, Venus, Amelogen Plus, P90, Z350, Esthet-X, Amaris, Vita-l-escence, Natural-Look, Charisma, Z250 and Opallis). The polymerization shrinkage percentage was calculated using a video-image recording device (ACUVOL—Bisco Dental) and the hygroscopic expansion was measured after thermocycling aging in the same equipment. Equal volumes of material were used and, after 5 min of relaxation, baseline measurements were calculated with 18 J of energy delivered from the light-curing unit. Specimens were stored in a dry-dark environment for 24 h then thermocycled in distilled water (5–55 °C for 20,000 cycles) with volume measurement at each 5000 cycles. In addition, the pulse-excitatory method was applied to calculate the elastic modulus and Poisson ratio for each res...

Evaluation of polymerization shrinkage and Vickers hardness for restorative dental composites

Materials Today: Proceedings, 2019

In this article, BisGMA and TEGDMA were used as resin material to fabricate dental composite. Camphorquinone was used as photoinitiator and DMAEA was used as coinitiator. Different %wt of micro sized zinc oxide (0%, 3%, 6% and 9%) was used as filler to study the effect of different compositions of zinc oxide filled dental composite. Resin matrix with different compositions were prepared to fabricate dental composite samples. Polymerization shrinkage and Vickers micro-hardness were measured. This study reveals experimentally that introduction of zinc oxide in dental resin significantly reduces polymerization shrinkage and improves micro-hardness of the restorative dental composite. Minimum polymerization shrinkage of 8.02% and maximum micro-hardness of 80 H v were achieved at 9 %wt of zinc oxide as filler in dental composite.

Shrinkage of Dental Composite Resin: ContemporaryUnderstanding its Enigmas and How to Solve? A Reviewc

2020

Citation: Nagy Abdulsamee., et al. “Shrinkage of Dental Composite Resin: Contemporary Understanding its Enigmas and How to Solve? A Review”. EC Dental Science 19.5 (2020): 03-17. Abstract Nowadays dental patients are seeking a restorative material to their teeth that fulfilled most of the ideal requirements for such use especially aesthetic and functional performance needs. Traditionally composite resin can fulfill these requirements but with the major drawback of shrinkage during polymerization. The shrinkage will be manifested as marginal leakage, cuspal deflection, tooth or restoration fracture, postoperative sensitivity that ends ultimately by failed restoration. The aim of the current work was to pay attention of dental workers to the origin of polymerization shrinkage, its consequences, factors affecting, methods used to measure it, and how can they minimize it for promoting longevity of the restoration.

Polymerization shrinkage of resin-based composites for dental restorations: A digital volume correlation study

Dental Materials, 2019

Objective. Resin-based composites are widely used in dental restorations; however, their volumetric shrinkage during polymerization leads to several issues that reduce the restoration survival rates. For overcoming this problem, a deep study of shrinkage phenomena is necessary. Methods. In this study, micro-tomography (-CT) is combined with digital volume correlation (DVC) to investigate the effect of several factors on the polymerization strain of dental composites in model cavities: the presence/absence of an adhesive, the use of transparent/blackened cavities, and irradiation times between 1 and 40 s. Results. The results indicate that the presence of an adhesive at the interface between the cavity and composite does not reduce the total strain but instead limits it to a preferential direction. In addition, regardless of the conditions, the main strain is generated along the axis parallel to the polymerization irradiation (the vertical axis). Finally, the total strain appears to occur in the first 5 s of irradiation, with no further evolution observed for longer irradiation times. Significance. This work provides new insight into resin-based composite shrinkage and demonstrates the benefit of coupling DVC and-CT to better understand the degradation mechanisms of these materials.

Degree of conversion and microhardness of dental composite resin materials

Journal of Molecular Structure, 2013

h i g h l i g h t s " Light cured dental composite materials are tested. " Degree of conversion of resin monomers to polymer network is measured. " Fourier transform infrared spectroscopy and microhardness are compared. " Microhardness could not substitute Fourier transform infrared spectroscopy.

Effects of Light Curing Method and Exposure Time on Mechanical Properties of Resin Based Dental Materials

European Journal of Dentistry, 2008

ABSTRACTObjectives: The aim of this study was to investigate microhardness and compressive strength of composite resin (Tetric-Ceram, Ivoclar Vivadent), compomer (Compoglass, Ivoclar, Vivadent), and resin modified glass ionomer cement (Fuji II LC, GC Corp) polymerized using halogen light (Optilux 501, Demetron, Kerr) and LED (Bluephase C5, Ivoclar Vivadent) for different curing times.Methods: Samples were placed in disc shaped plastic molds with uniform size of 5 mm diameter and 2 mm in thickness for surface microhardness test and placed in a diameter of 4 mm and a length of 2 mm teflon cylinders for compressive strength test. For each subgroup, 20 samples for microhardness (n=180) and 5 samples for compressive strength were prepared (n=45). In group 1, samples were polymerized using halogen light source for 40 seconds; in group 2 and 3 samples were polymerized using LED light source for 20 seconds and 40 seconds respectively. All data were analyzed by two way analysis of ANOVA and ...

A Comparative Evaluation of Microleakage of Two Low-Shrinkage Composites with a Conventional Resin Composite: an In Vitro Assessment

2016

Statement of the Problem Polymerization shrinkage stress in composite restorations may lead to microleakage. Clinical methods such as using low-shrinkage composites have been suggested to overcome this problem; however, there are controversies about their efficiency in decreasing the microleakage. Purpose This in vitro study was conducted to compare the microleakage of two low-shrinkage resin composites with a conventional one. Materials and Method Fifty class V cavities of 2.5×3×2 mm (depth× length× width) were prepared in the buccal surfaces of intact bovine incisor teeth with the incisal margin on the enamel and gingival margin on the cementum. The teeth were randomly divided into 5 groups. In group 1, Clearfil APX (conventional) with SE Bond was used in 2 layers (Kuraray; Japan). In group 2, GC Kalore (low –shrinkage) with GC UniFil Bond was applied in one layer (GC Company). In group 3, the material of group 2 was applied in two layers. In group 4, FiltekP90 (low –shrinkage) wi...