Light-cured Dental Resins Research Articles

Optimal resin monomer ratios for light-cured dental resins

Monomer ratios play a crucial role on the performances of dental resins, the optimal monomer ratios for dental resins are determined by combining the degree of conversion (DC), rate of polymerization (Rp), and mechanical properties, based on commonly-used Bis-GMA (bisphenol A-glycidyl methacrylate), UDMA (urethane dimethacrylate), and TEGDMA (triethyleneglycol dimethacrylate) resins. The DC and mechanical properties of the dental resins are examined by NIR (Near Infrared Ray) spectroscopy and nanoindentation tests, respectively. The results indicate that the Rp increases while the DC decreases with the loading content of Bis-GMA or UDMA in dental resins (i.e., Bis-GMA/TEGDMA and UDMA/TEGDMA). Meanwhile, both elastic modulus and hardness also present a tendency to increase. Various different monomers maybe create a strong polymer matrix in proper proportions, comprehensively comparing the performances of dental resins in different monomer ratios, the cured resins containing Bis-GMA (15–35 wt%), UDMA (37–60 wt%) and TEGDMA (20–35 wt%) show better material properties. The present study offers a quantitative analysis for Bis-GMA/UDMA/TEGDMA dental resins as well as provides guidance for the research of dental resins.

Changes in color and contrast ratio of resin composites after curing and storage in water

PurposeTo verify the color change and contrast ratio of resin composites after curing and after 30 days of storage in water. MethodsDentin A2 shades of different light-cured dental resin composites (Vittra APS, FGM, Brazil; Z350 XT, 3M ESPE, EUA; Tetric N-Ceram, Ivoclar Vivadent, Liechtenstein, and Charisma Diamond, Heraeus Kulzer, Germany) were tested. Ten rounded specimens (8 mm × 2 mm) were prepared for each material. Reflectance for all samples was obtained using a spectrophotometer (Minolta CM 3700d, Konica Minolta, Japan) before curing, immediately after curing, and after 30 days of storage in water. The color change (ΔE*lab) and contrast ratio (CR) data were analyzed using a one-way analysis of variance with Tukey's and paired t-tests (α = 1%). ResultsFor all materials tested, significant color changes were noticeable after curing and after 30 days in water (p < 0.01). Significant changes in the CR values before curing, after curing, and 30 days of storage in water were observed in the resin composites investigated (p < 0.01) except for Z350 (p > 0.01). ConclusionThe CR values and color changes after curing and 30 days of storage in water varied depending on the material tested. This study corroborates the clinical practice of curing a small amount of unpolymerized resin composite on the tooth surface to select the desired shade before undertaking esthetic restorative procedures.

Comparative study of free-volume changes in light-cured (dimeth)acrylate-type dental resin composites affected to artificial aging in dry-air and water-immersed mode

This research is intended to compare degradation processes in light-cured (dimeth)acrylate-type polymer/filler dental composites affected to aging in dry-air and water-immersed mode. The positron annihilation lifetime (PAL) spectroscopy has been employed to study changes in atomic-deficient structure in these composites under aging. Under light-curing polymerization initiating crosslinking of monomer chains, fragmentation of free-volume holes in resin matrix dominates over enhanced fraction of trapped positrons, since filler–particles assemblies get to be more tightly covered by surrounding polymer causing disappearing of interfacial voids at the filler–polymer surface. Therefore, the PAL spectra-transforming trend in light-cured composites obeys inverse positron-to-Ps trapping conversion. In contrast, the PAL spectra-transforming trend in these restoratives under aging obeys direct Ps-to-positron trapping conversion. After dry-air aging, the observed changes in the density of annihilation sites are ascribed to a strong agglomeration of Ps-decay holes in polymer sub-system accompanied by weaker agglomeration and appearance of positron traps in filler–polymer sub-system. Under the water aging, the agglomeration of Ps-decaying holes in the polymer sub-system is suppressed due to absorbed water molecules, this effect being slightly revealed at lower polymerization. New positron traps are observed at the filler–polymer interfaces in all light-cured composites. The agglomerated Ps-decay holes in a polymer matrix and positron traps inside filler–particles assemblies and filler–polymer interfaces of artificially aged composites cause their progressive microcracking.

Optimal photoinitiator concentration for light-cured dental resins

In this paper, we study the optimal photoinitiator (camphorquinone, CQ) concentration for light-cured dental resins by combining such properties as the degree of conversion, mechanical properties, and curing depth (the depth at which the hardness is 80% of the surface hardness). The material properties of the light-cured dental resins (Bis-GMA/TEGDMA in a mass ratio of 70:30) are characterized by in-situ near-infrared (NIR) spectroscopy and nanoindentation tests. Experimental results indicate that the degree of conversion (DC) and mechanical properties such as elastic modulus and hardness increase, while the curing depth decreases with the increase of CQ concentration. However, above a certain concentration (~0.5 wt%), these properties do not benefit from the further increasing CQ concentration because of potential self-annihilation between free radicals. The presented study offers a method to determine the optimal photoinitiator concentration for light-cured resins and establishes the correlations between the photoinitiators, polymerization kinetics, and mechanical properties of the light-cured resins.

Evaluation of the Degree of Conversion, Residual Monomers and Mechanical Properties of Some Light-Cured Dental Resin Composites.

The novelty of this study consists in the formulation and characterization of three experimental dental composites (PM, P14M, P2S) for cervical dental lesion restoration compared to the commercial composites Enamel plus HRi® - En (Micerium S.p.A, Avengo, Ge, Italy), G-ænial Anterior® - Ge, (GC Europe N.V., Leuven, Belgium), Charisma® - Ch (Heraeus Kulzer, Berkshire, UK). The physio-chemical properties were studied, like the degree of conversion and the residual monomers in cured samples using FTIR-ATR (attenuated total reflectance) and HPLC-UV (ultraviolet detection), as well as the evaluation of the mechanical properties of the materials. The null hypothesis was that there would be no differences between experimental and commercial resin composites regarding the evaluated parameters. Statistical analysis revealed that water and saliva storage induced significant modifications of all mechanical parameters after three months for all tested materials, except for a few comparisons for each type of material. Storage medium seemed not to alter the values of mechanical parameters in comparison with the initial ones for: diametral tensile strength (DTS-saliva for Ge and PM, compressive strength (CS)-water for Ch, DTS-water and Young’s modulus YM-saliva for P14M and YM-water/ saliva for P2S (p > 0.05). Two of the experimental materials showed less than 1% residual monomers, which sustains good polymerization efficiency. Experimental resin composites have good mechanical properties, which makes them recommendable for the successful use in load-bearing surfaces of posterior teeth.

Calcium phosphate coating on dental composite resins by a laser-assisted biomimetic process

ObjectivesDental composite resins with better biocompatibility and osteoconductivity have been sought in endodontic treatments. This study aimed to develop a technique to produce the osteoconductive resin surfaces through calcium phosphate (CaP) coating using a laser-assisted biomimetic (LAB) process. MethodsLight-cured, acrylic-based composite resins were used as substrates. The resin substrate was subjected to a LAB process comprising Nd:YAG pulsed laser irradiation in a supersaturated CaP solution. The LAB-processed substrate was immersed for 3 days in a simulated body fluid (SBF) for the preliminary osteoconductivity assessment. ResultsAfter irradiation for 30 min, the resin surfaces were partly coated with a newly formed CaP layer. The coating layer contained hydroxyapatite as the main crystalline phase and the coating coverage depended on the laser wavelength and the type of resin. The LAB-processed CaP-coated surface exhibited apatite-forming ability in SBF. ConclusionsLAB process is effective for CaP coating on light-cured dental composite resins and improving their osteoconductivity. Clinical significanceThe LAB process is a potential new tool to create a cementum-like osteoconductive surface on dental composite resins.

Polymerization stress of dental resin composite continues to develop 12 hours after irradiation.

This study assessed the development of stress from polymerization of light-cured dental resin composites for 24 hours after irradiation. Initial cracks were made near the edge of a cylindrical hole in glass, and crack lengths were measured. Revolution Formula 2, Kalore and Venus Diamond were polymerized in the hole. Crack lengths were measured at several intervals after irradiation up to 24 hours. Stresses at the composite-glass interface were calculated using the crack lengths. Elastic moduli of the composites were measured at the same time intervals. Interfacial stress and elastic modulus were significantly related to material and time. Stress continued to increase up to 12 hours after irradiation. Significantly lower stresses were measured in Kalore and Venus Diamond than Revolution Formula 2 throughout 24 hours. Stress at 24 hours was two times greater than the stress at 30 minutes. The increase in elastic modulus from 30 minutes to 24 hours ranged from 8 to 24%, which was less than the increase in stress over the same time period. Interfacial stress and elastic modulus of the composites demonstrated the average increases of 155% and 14%, respectively, from 30 minutes to 24 hours after irradiation. Since the elastic modulus is a measure of stiffness and resistance to load, clinicians might consider advising their patients to avoid heavy occlusal function until the elastic modulus has reached a plateau, which would be 60 minutes for Venus Diamond, 12 hours for Kalore, and 24 hours for Revolution Formula 2.

Electromagnetic Fields from Dental Devices and their Effects on Human Health

Magnetic fields can cause human health problems. Low-frequency electromagnetic fields are sometimes induced by electric currents in metallic objects that are worn or used in or on the body, and are unlike the high-frequency electromagnetic fields that produce heat. In low-frequency magnetic fields, the strength of the induced electric current is believed to be more important than the magnetic field strength in terms of effects on the health of living bodies. Electrically powered dental devices, including personal devices such as electric toothbrushes and professional devices such as curing lights for light-cured dental resins, are widely used because of their convenience, but the electric circuits and motors that power them produce low-frequency electromagnetic waves. These magnetic fields induce electric currents in teeth and in metallic appliances that are set in the oral cavity. The effects of these induced currents on human health must therefore be considered. Investigations of this issue revealed that magnetic fields from dental devices promoted the corrosion of intraoral metallic appliances via the induced currents, and this is likely to cause metallic allergies. Almost all reports on the effects of magnetic field exposure, including this corrosion phenomenon, describe harmful effects on human health. However, there may be some effective uses of the magnetic fields generated by dental devices for human health promotion. Oral bacteria were found to corrode orthodontic stainless steel appliances, but magnetic field-induced currents in these appliances could provide remarkable protection effects against this microbially induced corrosion. In this review, we discuss the results and conclusions of these investigations especially about novel ways of harmful effects and effective use of magnetic fields from dental devices, and conclude that further detailed studies are required to clarify their detailed mechanisms and to develop countermeasures for protection from or effective use of these fields.

Influence of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; as Filler Loading on the Fracture Toughness of Light-Cured Dental Resin Composites

The purpose of the present study was to evaluate the effect of filler loading on the fracture toughness of light-cured dental resin composites (DRCs). The monomer Bis-GMA and TEGDMA (75/25 wt/wt) were mixed with treated micro-sized aluminum oxide (Al2O3) particles ranging from 40-60 wt% as filler. The composite samples were cured with LED for 80s. The bulk density (g/cm3) and apparent porosity (%) of the samples were determined according to the ASTM standard. The fracture toughness (KIC) values of the composites were determined using a single edge notched specimen in the three-point bending test. There was a significant difference in KIC of the composites with different loading of Al2O3 particles (p &lt; 0.05). The highest amount of filler (60 wt%) reduced the KIC value to 1.5 MPa.m1/2. As a conclusion, the Al2O3 particles used as filler loading does have an effect on the mechanical properties of DRCs.

Effect of alumina particles loading on the mechanical properties of light-cured dental resin composites

The purpose of this study is to evaluate the effect of alumina (Al2O3) loading on the mechanical properties of dental resin composites (DRCs). The DRCs were prepared based on Al2O3 particles and bisphenol A-glycidyl methacrylate (Bis-GMA) was used as the base monomer. The silane-treated Al2O3 particles were mixed with the resin matrix in proportions of 40, 50, and 60wt%, respectively. Resin matrix without filler was used as the control sample. The Vickers hardness (HV) and flexural modulus (FM) of the DRCs mixed with Al2O3 particles were found to be superior compared to the control sample; the values increased from 14.4 to 23.5kg/mm2 and 1.5 to 5.7GPa, respectively. However, the flexural strength (FS) values of DRCs were slightly decreased as the filler loading increased i.e. from 84.5 to 74.2MPa. The results also revealed statistically significant increases in the HV and FM. On the other hand, FS values showed significant decrease when filler loading was increased (P<0.05).

紫色半導体レーザーを用いた光重合型レジン系材料の硬化とその特性

The violet laser diode was developed in 1996, and is now widely used as a light source for high-speed multilayer recording systems such as Blu-ray discs and HD-DVD systems. These lasers also show promise for medical applications, such as cutting soft tissue, laser acupuncture, tooth whitening, and detection of dental caries. The wavelength of the violet laser diode (approx. 405nm) may be suitable for hardening light-cured dental materials combined with some alternative photo-initiators. This article examines the light-curing efficiency of some commercial and three experimental dental resins by GaN-based violet laser diode determined in terms of ultimate micro-tensile strength, in comparison with curing by various commercial LED light-curing units. The spectral characteristics of the transmittance of contemporary dental adhesives and the emission of several commercially available light-curing units are also presented. The results revealed that violet laser diodes can be used as a light-curing source to initiate the polymerization of light-cured dental resins.

歯科用コンポジットレジンの光照射距離依存性 I 培養細胞への影響

歯科用コンポジットレジンの光照射距離依存性 I 培養細胞への影響

Sorption of water, ethanol or ethanol/water solutions by light-cured dental dimethacrylate resins

Objectives This work is concerned with the study of the sorption and desorption process of water, ethanol or ethanol/water solution 50% (v/v) or 75% (v/v) by the dental resins prepared by light curing of Bis-GMA, Bis-EMA, UDMA, TEGDMA or D 3MA. Methods A thin resin disc is placed in a bath of time to obtain the sorption curve m t = f( t). Then the liquid is desorbed until a constant mass for the disc is reached and the desorption curve is recorded. These experimental curves help in the determination of the sorbed/desorbed liquid amount at equilibrium, the percentage of the extracted mass of unreacted monomer known as “solubility”, and the sorption/desorption diffusion coefficient which expresses correspondingly the rate of the liquid sorption/desorption. Results The highest liquid uptake by dental resins was 13.3 wt% ethanol for Bis-GMA-resin, 12.0 wt% ethanol for UDMA-resin, 10.10 wt% ethanol/water solution for TEGDMA-resin, 7.34 wt% ethanol for D 3MA-resin and 6.61 wt% ethanol for Bis-EMA-resin. The diffusion coefficient for all resins was higher in water than in ethanol/water solution or ethanol. Bis-GMA-resin showed the highest diffusion coefficient (11.01 × 10 −8 cm 2 s −1) followed by Bis-EMA-resin (7.43 × 10 −8 cm 2 s −1), UDMA-resin (6.88 × 10 −8 cm 2 s −1), D 3MA-resin (6.22 × 10 −8 cm 2 s −1) and finally by TEGDMA-resin (1.52 × 10 −8 cm 2 s −1). Significance All studied dental resins, except TEGDMA-resin, absorbed higher amount of pure ethanol than water or ethanol water solution. TEGDMA-resin absorbed higher amount of ethanol/water solution (50/50 or 75/25 (v/v)) than water or ethanol. For all studied dental resins the diffusion coefficient was higher in water than in ethanol/water solution or ethanol.

Light-curing of dental resins with GaN violet laser diode: The effect of photoinitiator on mechanical strength

The purpose of this study was to evaluate whether a Gallium Nitride (GaN) -based violet laser diode (VLM500) could be used as a light source for light-cured dental resins. Three experimental unfilled resins containing different photoinitiators (camphorquinone, CQ; phenyl propanedione, PPD; or mono acylphosphineoxide, MAPO) were evaluated. These resins were light-cured with a VLM500 laser diode, and their ultimate micro-tensile strengths (μTS) were compared to those cured with three different LED light sources (Curenos, G-Light Prima-normal mode and G-Light Prima-PL mode). The VLM500 produced high μTS values in all three resins, and we concluded that this violet laser diode can be used as a light source for light-cured dental resin materials.

Shrinkage forces due to polymerization of light-cured dental composite resin in cavities

A new method has been developed for determining shrinkage forces due to polymerization of light-cured dental composite resin in artificial cylindrical cavities. The cavities were fabricated in stainless steel plates, and shrinkage forces were measured using a load cell inserted from the rear of the plate in place of the floor of the cavity. The cavities were 3 mm in diameter, and depths varied from 0.5 to 3.5 mm to study the effect of light intensity. Cavities were filled with a composite resin after being prepared with a bonding agent and were then irradiated for 20 s with a light-curing unit at a power of 300 mW/cm 2. To study the effects of boundaries, two conditions were employed: a free surface condition without any restriction on the top surface of the cavity, and a constrained surface condition in which the top surface of the resin was bonded to a 1 mm thick transparent polymethyl methacrylate (PMMA) plate. The shrinkage forces were measured as functions of time and the cavity depth, and the following results were obtained. For both conditions, the force increased with time, mostly during the irradiation stage (20 s), and then increased slightly after the irradiation. The force measured at 300 s increased gradually with the cavity depth and exhibited a maximum value before decreasing gradually. The cavities with constrained surfaces yielded much greater shrinkage forces for any given cavity depth than those with free surface conditions.

Influence of Background Color on the Chromatic Value of Four All-Ceramic System Core Materials

This study aims to investigate the effect of background color on the chromatic value of four all-ceramic system core materials at clinically appropriate thicknesses. Disc specimens with 15 mm in diameter and thicknesses ranging from 0.5±0.01mm In-Ceram zirconia core, Cercon base zirconia core, and Cercon base color zirconia core) to 0.8±0.01mm (Empress II) were fabricated. A colorimeter (CIE- 1976-Lab) measured the chromatic value of all samples placed on a high-noble metal-ceramic alloy and a visible light-cured dental composite resin (A2 color) background, after which the color difference was calculated. The color difference of Empress II samples was more than 1.5 among different background color groups, while that of Zirconia was less than 1.5. The influence of background color on the Empress II dentin was visible, such that it could be used on a tooth color post. Meanwhile, the influence of background color was invisible for the three kinds of Zirconia core materia1s, such that the materials developed excellent color-masking abilities and could be adapted for use on any color background.

CARDIOVASCULAR HEALTH: Exploring a Potential Link between BPA and Heart Disease

Most people in the United States are exposed to the plastic monomer bisphenol A (BPA), whether in plastic linings in food cans, containers made of hard plastic, or other plastics and foods containing BPA. Exposure to this suspected endocrine disruptor is illustrated by urine samples collected for NHANES (the National Health and Nutrition Examination Survey), for which the Centers for Disease Control and Prevention surveys thousands of adults and children. A new analysis of NHANES data published 13 January 2010 in PLoS ONE adds more evidence for an association between heart disease and higher exposures to BPA, even at the relatively low levels seen in the general population. David Melzer, an epidemiologist at the University of Exeter, United Kingdom, and his colleagues first looked at NHANES data collected from 2003 and 2004; their results, published in the 17 September 2008 issue of JAMA, were the first to show an association between higher levels of BPA metabolites in urine and adverse adult health outcomes, including heart disease. The current analysis considered NHANES data from 2005 and 2006. Although the BPA levels in urine samples from this new group of people were lower by almost a third, the association remained between coronary heart disease and higher urinary BPA. While this study may help inform future research, such cross-sectional studies “should not be used to demonstrate that a particular chemical can cause a particular effect,” said Steven G. Hentges of the Polycarbonate/BPA Global Group of the American Chemistry Council in a 13 January 2010 press release. And indeed, Melzer and his colleagues emphasize that because this study is cross-sectional—a snapshot in time instead of a long-term observational investigation—they cannot say whether BPA contributes to heart disease or if heart disease changes the exposure to or metabolism of BPA in adults. “What would really help is if industry and regulators could support independent studies [to examine] whether high BPA levels are present before any disease started,” Melzer says. “Chasing human [data] is the way forward,” says Richard Sharpe, an endocrinologist from The Queen’s Medical Research Institute in Edinburgh who did not participate in the research. NHANES provides a robust data set, he says, and the repeatability of the association with a second survey group is positive. However, that replication is somewhat incomplete because not all of the associations found with BPA in the first study were found in the second. “The more logical interpretation of the results as they stand at the moment is that they are looking at two variables that are associated with something else,” Sharpe says. Diet, for instance, is a major contributor to heart disease in the United States and also a major source of BPA exposure. “We should remember that heart disease develops over a long period of time,” Sharpe says, “so if BPA is involved causally, a cross-sectional study such as this [PLoS ONE report] cannot show this.” Scott Belcher, a scientist at the University of Cincinnati, says the association in humans is “not super surprising in light of our animal studies and because we already know estrogens are related to various cardiovascular end points.” Belcher’s team reported at the June 2009 Endocrine Society annual meeting that BPA exposure in vitro in muscle cells and in whole hearts from female rodents leads to arrhythmias, and they recently received American Recovery and Reinvestment Act funds from the NIEHS to conduct further research on BPA in mice. Meanwhile, pending the release of an updated toxicology review for BPA, the Food and Drug Administration announced in January 2010 it is “taking reasonable steps to reduce human exposure to BPA in the food supply.”

Effect of porous glass–ceramic fillers on mechanical properties of light-cured dental resin composites

Objectives The aim of this work was to study the effect of porous particles on the mechanical properties of dental resin composites. Methods Two kinds of glass–ceramic powders with different calcium–mica to fluorapatite ratio were used as inorganic fillers for light-cured dental resin composites. The glass–ceramic particles were etched to introduce porous structures. The microstructures of particles and the fractography of dental composites were observed using SEM/EDS. The crystalline phases in the fillers were determined by XRD. The specific surface areas (SBET) of porous fillers were tested to show the degree of porosity. 6 samples were prepared for each bending strength test, which was conducted in a Mechanical Testing System. Results The results show that the bending strength does not vary monotonically with the porosity of the particles. For the glass–ceramics with a high nominal calcium–mica to fluorapatite ratio, the dental resin filled with porous particles has a higher strength than that filled with dense particles; however, for the glass–ceramics with a low nominal calcium–mica to fluorapatite ratio, the dental resin filled with porous particles has a lower strength. Significance The study indicates that the porosity itself is not a decisive factor for strengthening of dental resin composites. The composition of the glass–ceramic particles and the porous structure are also essential factors influencing the mechanical strength. The investigation on the effect of porous glass–ceramic fillers will provide more understanding on the mechanical properties of dental resin composites and will help with the design of new dental restorative materials.

Physical Properties of a Hybrid and a Nanohybrid Dental Light-Cured Resin Composite

This work was aimed at the study of some physical properties of two current light-cured dental resin composites, Rok (hybrid) and Ice (nanohydrid). As filler they both contain strontium aluminosilicate particles, however, with different size distribution, 40 nm–2.5 μm for Rok and 10 nm–1 μm for Ice. The resin matrix of Rok consists of UDMA, that of Ice of UDMA, Bis-EMA and TEGDMA. Degree of conversion was determined by FT-IR analysis. The flexural strength and modulus were measured using a three-point bending set-up according to the ISO-4049 specification. Sorption, solubility and volumetric change were measured after storage of composites in water or ethanol/water (75 vol%) for 1 day, 7 or 30 days. Thermogravimetric analysis was performed in air and nitrogen atmosphere from 30 to 700°C. Surface roughness and morphology of the composites was studied by atomic force microscopy (AFM). The degree of conversion was found to be 56.9% for Rok and 61.0% for Ice. The flexural strength of Rok does not significantly differ from that of Ice, while the flexural modulus of Rok is higher than that of Ice. The flexural strengths of Rok and Ice did not show any significant change after immersion in water or ethanol solution for 30 days. The flexural modulus of Rok and Ice did not show any significant change either after immersion in water for 30 days, while it decreased significantly, even after 1 day immersion, in ethanol solution. Ice sorbed a higher amount of water and ethanol solution than Rok and showed a higher volume increase. Thermogravimetric analysis showed that Rok contains about 80 wt% inorganic filler and Ice about 75 wt%.

Dynamic Mechanical Analysis of a Hybrid and a Nanohybrid Light-Cured Dental Resin Composite

This work was aimed at the study of the viscoelastic properties of two current light-cured dental resin composites, Rok (hybrid) and Ice (nanohybrid), by dynamic mechanical analysis, under the influence of variable temperatures and frequencies 1 h after curing or after storage at 37°C either in air or distilled water for 1, 7 or 30 days. They both contain about the same amount of filler, which is strontium aluminosilicate particles, but they have different size distribution, 40 nm–2.5 μm for Rok and 10 nm–1 μm for Ice. The resin matrix of Rok consists of UDMA, while that of Ice consists of UDMA, Bis-EMA and TEGDMA. During dynamic testing elastic modulus (E′), viscous modulus (E″) and loss tangent (tan δ) were determined over a temperature range from 25 to 185°C at a frequency of 0.1, 1.0 or 10.0 Hz. The elastic modulus (8.40 ± 0.61 GPa) and tan δ (0.114) of Rok at 37°C and 1 Hz was slightly higher than that of Ice (E′ = 7.58 ± 0.50 GPa and tan δ = 0.110) which, however, were not statistically different (P ≤ 0.05). Both the light-cured composites showed two T g values, at 58 and 121°C for Rok and at 63 and 117.0°C for Ice. The first T g has an apparent value, since inside the glass transition region an additional curing reaction occurred of the unreacted C=C methacrylate groups; the second T g is due to the new material formed during the DMA scan. During the storage of composites in air or water also an additional curing reaction took place. The nanohybrid Ice showed a slight lower elastic modulus and tan δ than the hybrid Rok at 25–50°C, which, however, were not statistically different (P ≤ 0.05).