Compressive strength of glass ionomer cements using different specimen dimensions

An Evaluation of Experimental Calcium Ion-Leachable Nanocomposite Glass Ionomer Cements

Glass ionomer cements (GICs) are among the main restorative dental materials used broadly in daily clinical practice. The incorporation of clay nanoparticles as reinforcing agents is one potential approach to improving GIC properties. This study aims to investigate whether the incorporation of calcium-modified clay (Ca-clay) nanoparticles in conventional GICs alters their structural characteristics, along with their physicochemical and mechanical properties. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were performed to assess the surface characterization of GIC nanocomposites, whereas a setting reaction was carried out via an attenuated total reflection Fourier transform infrared spectrometer (ATR-FTIR). A universal testing machine was used for compression tests, while calcium ion release was quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). GIC composite groups reinforced with Ca-clay were found to release a fine amount of calcium ions (5.06-9.91 ppm), with the setting reaction being unaffected for low Ca-clay loadings. The median compressive strength of 3 wt% in the Ca-clay group (68.97 MPa) was nearly doubled compared to that of the control group (33.65 MPa). The incorporation of Ca-clay nanoparticles in GICs offers a promising alternative among dental restorative materials regarding their chemical and mechanical properties.

Physicochemical and histological analysis of an experimental endodontic repair material containing 45S5 bioactive glass

This study aimed to evaluate the maximum compressive strength, the modulus of elasticity, pH variation, ionic release, radiopacity and biological response of an experimental endodontic repair cement based on 45S5 Bioglass^®. An in vitro and in vivo study with an experimental endodontic repair cement containing 45S5 bioactive glass was conducted. There were three endodontic repair cement groups: 45S5 bioactive glass-based (BioG), zinc oxide-based (ZnO), and mineral trioxide aggregate (MTA). In vitro tests were used to evaluate their physicochemical properties: compressive strength, modulus of elasticity, radiopacity, pH variation, and the ionic release of Ca⁺ and PO₄. An animal model was used to evaluate the bone tissue response to endodontic repair cement. Statistical analysis included the unpaired t-test, one-way ANOVA and Tukey's test. BioG showed the lowest compressive strength and ZnO showed the highest radiopacity among the groups, respectively (p < 0.05). There were no significant differences in the modulus of elasticity among the groups. BioG and MTA maintained an alkaline pH during the 7 days of evaluation, both at pH 4 and in a pH 7 buffered solutions. PO4 was elevated in BioG, peaking at 7 days (p < 0.05). Histological analysis showed less intense inflammatory reactions and new bone formation in MTA. BioG showed inflammatory reactions that decreased over time. These findings suggest that the BioG experimental cement had good physicochemical characteristics and biocompatibility required for bioactive endodontic repair cement.

Effect of bacterial resistant zwitterionic derivative incorporation on the physical properties of resin-modified glass ionomer luting cement

Biofilms induce microbial-mediated surface roughening and deterioration of cement. In this study, zwitterionic derivatives (ZD) of sulfobetaine methacrylate (SBMA) and 2-methacryloyloxyethyl phosphorylcholine, were added in concentrations of 0, 1, and 3% to three different types of commercially available resin-modified glass ionomer cement (RMGIC) (RMC-I: RelyX Luting 2, RMC-II: Nexus RMGI, and RMC-III: GC FujiCEM 2). The unmodified RMGICs served as the control group for comparison. The resistance of Streptococcus mutans to ZD-modified RMGIC was evaluated with a monoculture biofilm assay. The following physical properties of the ZD-modified RMGIC were assessed: wettability, film thickness, flexural strength, elastic modulus, shear bond strength, and failure mode. The ZD-modified RMGIC significantly inhibited biofilm formation, with at least a 30% reduction compared to the control group. The addition of ZD improved the wettability of RMGIC; however, only 3% of the SBMA group was statistically different (P < 0.05). The film thickness increased in proportion to the increasing ZD concentrations; there was no statistical difference within the RMC-I (P > 0.05). The experimental groups' flexural strength, elastic modulus, and shear bond strength showed an insignificant decrease from the control group; there was no statistical difference within the RMC-I (P > 0.05). The mode of failure differed slightly in each group, but all groups showed dominance in the adhesive and mixed failure. Thus, the addition of 1 wt.% ZD in RMGIC favorably enhanced the resistance to Streptococcus mutans without any tangible loss in flexural and shear bond strength.

Mechanical Properties and Antibacterial Effect on Mono-Strain of Streptococcus mutans of Orthodontic Cements Reinforced with Chlorhexidine-Modified Nanotubes

Recently, several studies have introduced nanotechnology into the area of dental materials with the aim of improving their properties. The objective of this study is to determine the antibacterial and mechanical properties of type I glass ionomers reinforced with halloysite nanotubes modified with 2% chlorhexidine at concentrations of 5% and 10% relative to the total weight of the powder used to construct each sample. Regarding antibacterial effect, 200 samples were established and distributed into four experimental groups and six control groups (4 +ve and 2 -ve), with 20 samples each. The mechanical properties were evaluated in 270 samples, assessing microhardness (30 samples), compressive strength (120 samples), and setting time (120 samples). The groups were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, and the antibacterial activity of the ionomers was evaluated on Streptococcus mutans for 24 h. The control and positive control groups showed no antibacterial effect, while the experimental group with 5% concentration showed a zone of growth inhibition between 11.35 mm and 11.45 mm, and the group with 10% concentration showed a zone of growth inhibition between 12.50 mm and 13.20 mm. Statistical differences were observed between the experimental groups with 5% and 10% nanotubes. Regarding the mechanical properties, microhardness, and setting time, no statistical difference was found when compared with control groups, while compressive strength showed higher significant values, with ionomers modified with 10% concentration of nanotubes resulting in better compressive strength values. The incorporation of nanotubes at concentrations of 5% and 10% effectively inhibited the presence of S. mutans, particularly when the dose-response relationship was taken into account, with the advantage of maintaining and improving their mechanical properties.

Comparative Evaluation of Compressive Strength and Diametral Tensile Strength of Conventional Glass Ionomer Cement and a Glass Hybrid Glass Ionomer Cement

Aim

The aim of this study is to compare and evaluate compressive strength (CS) and diametral tensile strength (DTS) of a conventional glass ionomer cement (GIC) and a glass hybrid GIC.

Materials and methods

Five samples each were prepared of GC Fuji IX and EQUIA Forte cements for CS testing and five samples of each material for tensile strength testing. Specimens were subjected to a universal testing machine. Comparison of CS and DTS among two study groups was made using an independent t-test for each. Level of significance was set at p ≤ 0.05.

Results

Both test values were on the higher side for EQUIA Forte cement as compared to conventional GIC (p ≥ 0.05). However, the differences in values were not statistically significant.

Conclusion

EQUIA Forte can serve as an alternative to conventional GIC in stress-bearing primary teeth areas. Considering several factors like cost-effectiveness, surface to be restored, moisture contamination, and time considerations, the material of choice can be tailored to one's needs.

Clinical significance

EQUIA Forte can serve as a viable alternative to conventional GIC because of its improved qualities.

How to cite this article

Kunte S, Shah SB, Patil S, et al. Comparative Evaluation of Compressive Strength and Diametral Tensile Strength of Conventional Glass Ionomer Cement and a Glass Hybrid Glass Ionomer Cement. Int J Clin Pediatr Dent 2022;15(4):398-401.

The Comparison of Biofilm Formation, Mechanical and Chemical Properties between Glass Ionomer Cement and Giomer

Aims:

The aim of this study was to compare compressive strength and its correlation with the surface morphology and chemical elements of GIC and Giomer, as well as to determine the fluoride amount effect on the bacterial biofilm formation of GIC and Giomer.

Background:

The liability of Glass Ionomer Cement (GIC) mechanical properties is overcome with better antibacterial properties among restorative materials. Another fluoride-releasing restorative material, such as Giomer, has been discovered and is expected to overcome the issues with GIC’s mechanical properties; however, no research has been conducted related to antibacterial properties in Giomer.

Objective:

To compare compressive strength and its correlation with the surface morphology and chemical elements, then determine the fluoride amount effect on the bacterial biofilm formation of GIC and Giomer.

Methods:

Sixteen specimens of GIC and Giomer were prepared for a compressive strength measurement with the Universal Testing Machine. Sixteen specimens of GIC and Giomer were incubated for three days with the Streptococcus mutans culture at 37°C. The bacterial colonization was calculated using the Colony Forming Unit (CFU) and bacterial adhesion was calculated using a Scanning Electron Microscope (SEM). The mechanical properties’ compressive strength measurement, surface morphology, and chemical elements analyses were performed using SEM-EDX.

Results:

The compressive strength of Giomer was higher than GIC (P=0.001). The higher compressive strength of Giomer was reflected by a predominant regular surface, fewer voids, smaller and denser particles, and a higher content of silica and carbon. The bacterial biofilm on the surface of Giomer was higher than GIC, although there was no significant difference. GIC and Giomer have identical chemical elements: C, O, F, Na, Al, Si, P, and Ca.

Conclusion:

The compressive strength of Giomer is better than GIC; however, the biofilm formation of Giomer is higher than GIC, whereas GIC has a higher fluoride content but inferior in surfaces morphology characteristic

Could different formulations of grape seed (vitis vinifera) influence the physical properties of conventional glass ionomer cement?

Objective:

The aim is to evaluate the ability of different formulations of grape seed (GS) to influence the physical properties of conventional glass ionomer cement (GIC).

Materials and Methods:

Five groups were considered; Group I: Unmodified GIC (control), II: 3% v/v GS oil-modified GIC, III: 5% v/v GS oil-modified GIC, IV: 3% v/v ethanolic extract of GS (EEGS)-modified GIC and V: 5% v/v EEGS-modified GIC. Assessment parameters were; compressive strength, shear bond strength, surface roughness, water sorption and solubility and color difference. A representative specimen of each group was used for being analyzed by the Fourier transformation infrared spectroscopy. Analysis of variance was used to compare the results, followed by a Tukey post hoc test (P < 0.05).

Results:

3% v/v GS oil-modified GIC only exhibited a significant increase in its compressive strength and shear bond strength. Concurrently, there was a significant decrease in surface roughness, water sorption and solubility for 3% v/v GS oil-modified GIC group (P < 0.05). The least color change was for 3% v/v GS oil-modified GIC, which is a clinically acceptable change.

Conclusions:

3% v/v GS oil-modified conventional GIC is an optimistic formulation of a restorative material with enhanced physical properties and agreeable esthetic.

Repair bond strength and degradation of glass ionomer cements after mechanical and chemical challenges

Aim: Little is known about the reparability of glass ionomer cements (GICs) after storage in acid environments. The aim of this study was to evaluate the solubility and repairability of GICs immersed in acid solutions and subjected to brushing. Methods: Thirty discs of each GIC (Vitremer, VitroFil LC, VitroFil, and Maxxion R) were divided into three immersion groups: distilled water, Coca-Cola, or hydrochloric acid (HCl), then subjected to brushing. The weight of discs was measured before and after the immersions to determine mass alteration. Each disc was repaired, by adding the same brand of GIC over its surface. After immersing the repaired specimens in same solutions, shear bond strengths using universal testing machine were measured. Two-way ANOVA and Tukey’s test was used (α=0.05). Results: Resin-modified GICs degrade after HCl immersion followed by brushing (p<0.05), while self-cured GICs were negatively affected by all challenges (p<0.05). The challenges decreased the repair strength for VitroFil LC (p<0.05), which had higher repair shear bond strength than the other GICs (p<0.05), exhibiting most cohesive failures. Conclusion: Self-cured GICs degraded when immersed in all acid solutions with brushing while resin-modified GICs only degraded following HCl immersion with brushing. Despite exhibiting the best repair results, VitroFil LC was the only GIC that was influenced by all the acid challenges.

Assessing the effect of ceramic additives on the physical, rheological and mechanical properties of conventional glass ionomer luting cement - An in-vitro study

Aim

To evaluate the effect of the addition of conventional ceramics on the physical, rheological and mechanical properties of conventional glass ionomer luting cement.

Materials and methods

5%, 10%, 15% and 20% (w/w) of Enamel and Body conventional ceramic additives (E44 Enamel and B96/c4 Body) were reinforced in the two commercially available glass ionomer luting cement – GC Fuji I (GC Corporation Tokyo, Japan) and Ketac Cem Radiopaque (3M ESPE AG). Setting time, film thickness and compressive strength of the cement was measured according to the American Dental Association Specification number 96 for luting cement. Enthalpy change of the cement reaction was measured with the help of Differential Scanning Calorimetry analysis. Compatibility between the sizes of powder particles was measured with the help of a particle size analyzer.

Results

5% of ceramic additive could not improve much of the compressive strength. Compressive strength increased significantly (p < 0.05) with the addition of 10% of ceramic additive, beyond which, there was a gradual decrease in strength. Although the setting time and film thickness were also shown to increase due to the additive, the former did not exceed the limit specified by the American Dental Association Specification number 96 (2–8 min for setting time and 25 microns for film thickness).

Conclusion

Addition of 10% of conventional ceramics resulted in a significant increase in the compressive strength of GIC Luting Cement without any significant compromise in its setting time. The substantial increase in film thickness is a major limitation. Use of ceramic additives with physical properties compatible with that of the glass ionomer cement may aid in increasing the compressive strength without compromising its setting time or film thickness.

Mechanical Properties of High Viscosity Glass Ionomer and Glass Hybrid Restorative Materials

OBJECTIVES

to determine the mechanical properties of hybrid and high-viscosity glass ionomer cements. Compressive strength and hardness of three glass ionomer cements (GIC) were measured: Ketac ™ Universal Aplicap ™, EQUIA Fil® and EQUIA FORTE Fil®, and the SEM sample analysis were performed.

MATERIALS AND METHODS

The samples for measuring the compressive strength were prepared using silicone molds with standard dimensions of 6 mm x 4 mm and stored in deionized water for five days, while the samples for hardness measurement were prepared using Teflon molds with a cylindrical opening in the middle, dimensions 2 mm in height and 5 mm in width. For each material, one sample was made (n = 1) and stored in deionized water at 37ºC for 25 days. A representative sample of each material was analyzed using SEM. For the comparison of obtained values, the ANOVA test was used, while Tukey test was used for the multiple comparison.

RESULTS

There were no significant differences between the compressive strength of the three tested materials (p <0.05). The hardness values were: 157 HV0,2 for Ketac ™ Universal Aplicap ™, 47 HV0,2 for EQUIA Fil® and 39 HV0,2 for EQUIA FORTE Fil®, respectively, and were significantly different, implying that Ketac ™ Universal Aplicap ™ has much higher hardness values than the other materials tested. SEM sample analysis revealed similar fracture modes of the tested materials.

CONCLUSION

It was concluded that there were no statistically significant differences in compressive strength and fracture modes between the tested materials, while Ketac ™ Universal Aplicap ™ hardness results were significantly higher than the ones measured for EQUIA Fil® and EQUIA FORTE Fil®.

A Comparative Evaluation of Mechanical Properties of Four Different Restorative Materials: An In Vitro Study

OBJECTIVES

The purpose of this study is to compare the mechanical properties (compressive strength (CS) and diametral tensile strength (DTS)) of four different restorative materials: conventional glass ionomer (Fuji IX), ClearFil AP-X, Filtex Z350-XT, and Cention N.

MATERIALS AND METHODS

Specimens (n = 80) were prepared from Fuji IX, ClearFil AP-X, Filtex Z350-XT, and Cention N for testing compressive strength and DTS.

STATISTICAL ANALYSIS

Results obtained were subjected to one-way ANOVA and Tukey's post hoc test at significance (p < 0.001).

RESULTS

There were significant differences among restorative materials tested. ClearFil AP-X exhibits the highest mechanical properties (CS and DTS) and least values were obtained by the Fuji IX.

CONCLUSION

Strength is one of the most important criteria for the selection of a restorative material. Stronger materials better resist deformation and fracture, presenting more equitable stress distribution, greater probability, and greater stability of clinical success.

HOW TO CITE THIS ARTICLE

Iftikhar N, Devashish, et al. A Comparative Evaluation of Mechanical Properties of Four Different Restorative Materials: An In Vitro Study. Int J Clin Pediatr Dent 2019;12(1):47-49.

The properties of experimental resin-modified glass-ionomer luting cements (RMGICs) containing novel monomers

OBJECTIVES

To investigate working and setting times, compressive fracture strength (CFS), compressive modulus (CM), three-point flexure strength (TFS) and tensile flexure modulus (TFM) of commercial, control and experimental RMGICs.

METHODS

RelyX Luting (RX, 3M-ESPE) and Fuji Plus (FP, GC), two control home liquids and eight new liquid compositions (F1-F4 and R1-R4) comprising different percentages of the monomer HPM (hydroxypropyl-methacrylate) and/or THFM (tetrahydrofurfuryl-methacrylate) with the original monomer HEMA (2-hydroxyethyl-methacrylate) were used in this study. The polymerization was initiated chemically (using benzene sulfonic acid sodium-salt in FP powder and potassium persulfate/ascorbic acid in RX powder). Home and experimental liquids were mixed with the corresponding commercial powder. An oscillating rheometer was used to measure the working and setting times (n=6). 20 cylinders per material (6.0±0.1mm height, 4.0±0.1mm diameter) were fabricated for CFS and CM testing, 20bars per material (25.0±0.1mm length, 2.0±0.1mm width, 2.0±0.1mm thickness) were made for TFS and TFM testing.

RESULTS

All RX compositions showed longer setting times (p≤0.0001) and lower CFS values compared to their FP counterparts (p≤0.0001). The TFS testing showed that commercial and home RMGICs behaved as brittle materials with linear load/deflection curve while experimental materials showed plastic ductile deformation before fracture. F3, F4 and F2 showed significantly higher CFS values compared to the corresponding home material (p≤0.0001).

SIGNIFICANCE

All new experimental compositions demonstrated working and setting times that are clinically acceptable. The new experimental FP compositions containing THFM (especially F3 and F4) demonstrated improved mechanical properties compared to their corresponding home material.

Study of the Mechanical Properties of the Novel Zirconia-reinforced Glass lonomer Cement

OBJECTIVES

The purpose of this in vitro study is to compare the compressive strength (CS) and diametral tensile strength (DTS) of the zirconia-reinforced restorative material (Zirconomer®) with conventional glass ionomers (Fuji 1X) and amalgam.

MATERIALS AND METHODS

Specimens (n = 120) were fabricated from silver amalgam, reinforced glass ionomer cement (GIC) (glass ionomer, Fuji 1X GC Corp.), and zirconia-reinforced glass ionomer (Zirconomer, Shofu Inc.) for testing the CS and DTS. The results were analyzed using analysis of variance, followed by a Tukey post hoc test.

RESULTS

Both CS and DTS were found to be significantly higher for the zirconia-reinforced GIC and silver amalgam compared with GIC (p < 0.001).

CONCLUSION

A newer class of restorative material like Zirconomer helps to overcome the potential hazard of mercury, but retains the strength and durability of amalgam as well as the sustained high-fluoride release of GICs. Furthermore, long-term studies are required to confirm its use as an alternative to the currently available posterior restorative material.

Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal

Glass-ionomer cements (GICs) are mainstream restorative materials that are bioactive and have a wide range of uses, such as lining, bonding, sealing, luting or restoring a tooth. Although the major characteristics of GICs for the wider applications in dentistry are adhesion to tooth structure, fluoride releasing capacity and tooth-colored restorations, the sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They have undergone remarkable changes in their composition, such as the addition of metallic ions or resin components to their composition, which contributed to improve their physical properties and diversified their use as a restorative material of great clinical applicability. The light-cured polymer reinforced materials appear to have substantial benefits, while retaining the advantages of fluoride release and adhesion. Further research should be directed towards improving the properties, such as strength and esthetics without altering its inherent qualities, such as adhesion and fluoride releasing capabilities.

An Invitro Comparative Evaluation of Compressive Strength and Antibacterial Activity of Conventional GIC and Hydroxyapatite Reinforced GIC in Different Storage Media

BACKGROUND

GIC is the most commonly used restorative material in pediatric dentistry since it has got various advantages like fluoride release, anticariogenic property and chemical adhesion to tooth but a major disadvantage is its contraindication in posterior teeth because of poor mechanical properties.

AIM

The purpose of this study is a modest attempt to explore the influence of the addition of 8% hydroxyapatite to conventional GIC on its compressive strength when immersed in different storage media and antibacterial activity.

MATERIALS AND METHODS

One hundred and twenty six pellets of the specific dimension of 6 x 4 mm were prepared and divided into 6 groups and were immersed in deionized water, artificial saliva, lactic acid solution respectively for three hours everyday over 30 days test period. The compressive strength was measured by using a universal testing machine (AG-50kNG) at cross head of 1mm(2)/min and strength was determined after 1 day, 7 days, 30 days respectively and the antibacterial activity evaluated against Streptococcus mutans strain in brain heart infusion broth using serial dilution method.

STATISTICAL ANALYSIS

Group wise comparisons were made by one-way ANOVA followed by post-hoc Tukey's test, Intergroup comparison was done with Mann-Whitney test.

RESULTS

GIC±HAp showed significantly greater antibacterial activity against Streptococcus mutans when compared to GIC group. There was no statistically significant change in the compressive strength among the groups except for group 3 and group 6 when immersed in lactic acid had shown significant difference at the end of 24 hours.

CONCLUSION

The addition of 8% hydroxyapatite to GIC showed marked increased in the antibacterial activity of the conventional GIC against caries initiating organism without much increase in the compressive strength of the GIC when immersed in the different storage media.

Effect of chlorhexidine gluconate on porosity and compressive strength of a glass ionomer cement

INTRODUCTION:For presenting wide antibacterial activity, chlorhexidine (CHX) has been extensively used in dentistry and can be easily incorporated into the glass ionomer cement (GIC) and consequently released into the oral cavity.AIM: The aim of this study was porosity and compression strength of a GIC, that was added to different concentrations of CHX.MATERIAL AND METHOD: Specimens were prepared with GIC (Ketac Molar Esaymix) and divided into 4 groups according to the concentration of CHX: control, 0.5% and 1% and 2% (n = 10). For analysis of pores specimens were fractured with the aid of hammer and chisel surgical, so that the fracture was performed in the center of the specimens, dividing it in half and images were obtained from a scanning electron microscope (SEM) analyzed in Image J software. The compressive strength test was conducted in a mechanical testing machine (EMIC - Equipment and Testing Systems Ltd., Joseph of the Pines, PR, Brazil). Statistical analysis was performed by ANOVA, Tukey test. Significance level of 5%.RESULT: No statistically significant changes between the study groups was observed both for the number of pores as well as for the compressive strength.CONCLUSION: The use of GIC associated with CHX gluconate 1% and 2% is the best option to be used in dental practice.