Glass Ionomer Restorative Materials Research Articles

In-vitro evaluation of fracture resistance of teeth restored with different high-viscosity glass ionomer restorative materials and bulk-fill composite resins

ObjectivesThis study aimed to evaluate the effect of restorations made with a glass-hybrid restorative system (GHRS), a high-viscosity glass ionomer restorative material (HVGIC), a high-viscosity bulk-fill composite resin (HVB), a flowable bulk-fill composite resin (FB), and a nanohybrid composite resin (NH), which are commonly preferred in clinical applications on the fracture resistance of teeth in-vitro.Materials and methodsOne hundred intact human premolar teeth were included in the study. The teeth were randomly divided into ten groups (n = 10). No treatment was applied to the teeth in Control group. Class II cavities were prepared on the mesial surfaces of the remaining ninety teeth in other groups. For restoration of the teeth, a GHRS, a HVGIC, a HVB, a FB, and a NH were used. Additionally, in four groups, teeth were restored using NH, GHRS, and HVGIC with open and closed-sandwich techniques. After 24 h, fracture resistance testing was performed. One-way ANOVA and Tukey HDS tests were used for statistical analysis of the data.ResultsThe fracture resistance values of Control group were statistically significantly higher than those of GHRS, HVGIC, FB, NH, HVGIC-CS, GHRS-OS, and HVGIC-OS groups(p < 0.05). There was no statistically significant difference observed between the fracture resistance values of Control, HVB, and GHRS-CS groups (p > 0.05).ConclusionIt can be concluded that the use of HVB and the application of GHRS with a closed-sandwich technique may have a positive effect on the fracture resistance of teeth in the restoration of wide Class II cavities.Clinical relevanceThe use of high-viscosity bulk-fill composite resin and the application of glass-hybrid restorative system with the closed-sandwich technique in the restoration of teeth with wide Class II cavities could increase the fracture resistance of the teeth.

Dental restorative materials and halitosis: a preliminary in-vitro study

Despite the widespread use of dental restorative materials, little information exists in the literature regarding their potential impact on bad breath. This in vitro study aims to fill this gap by investigating the influence of different restorative materials on the release of hydrogen sulfide (H2S). Thirteen diverse dental restorative materials, including composites, flowable composites, glass ionomer restorative materials, high-copper amalgam, and CAD–CAM blocks, were examined. Cellulose Sponge models were used as negative and positive control. All samples were prepared with a diameter of 5 mm and a height of 2 mm. Except for the negative control group, all samples were embedded into Allium cepa L., and the emitted H2S was measured using the Wintact W8802 hydrogen sulfide monitor. Surface roughness’s effect on emission was explored by roughening the surfaces of CAD–CAM material samples, and gas emission was measured again. The data were statistically analyzed using the Kruskal–Wallis test and DSCF pairwise comparison tests. Fiber-reinforced flowable composite (EverX Flow), amalgam (Nova 70-caps), and certain composite materials (IPS Empress Direct, Tetric Evoceram, Admira Fusion X-tra) released higher H2S concentrations compared to the negative control. The H2S release period lasted longer in the same materials mentioned above, along with G-aenial Universal Injectable. Indirectly used materials, such as GC Cerasmart, Vita Enamic, and Vita YZ HT, demonstrated significantly lower emissions compared to other direct restoratives. Importantly, the surface roughness of indirect materials did not significantly affect peak H2S concentrations or release times. The study reveals variations in H2S release among restorative materials, suggesting potential advantages of indirect restorative materials in reducing H2S-induced halitosis. This comprehensive understanding of the relationship between restorative materials and halitosis can empower both dental professionals and patients to make well-informed treatment choices. Notably, there is evidence supporting the enhanced performance of indirect restorative materials for individuals affected by halitosis.

A Comparative Evaluation of the Shear Bond Strength of Three Different Hybrid Tooth-Colored Restorative Materials to Dentin: An In-Vitro Study.

Silver amalgam, glass ionomer, resin-modified glass ionomer, compomers, light polymerized hybrid composite resin, and hybrid glass ionomer are among the most frequent restorative materials used as cavity-based or post-endodontics. Thus, to meet the needs of both patients and dentists, Cention N reimagines the traditional filling by integrating bulk placement, ion release, and durability into a dual-curing, aesthetically pleasing solution. Hoewver, we do not have enough information from studies comparing this hybrid restorative material's shear bond strengths to dentin to draw any firm conclusions. Cention N, zirconomer, and Vitremer are three hybrid tooth-colored restorative materials that were evaluated for their shear bond strength to dentin. This research aimed to compare and evaluate these materials. The purpose of this research was to use a universal Instron machine to measure the shear bond stress of three distinct hybrid tooth-colored restorative materials in relation to dentin.The research samples consisted of 45 extracted lower first premolars from humans.The teeth were then assigned into three groups of 15 samples each according to different color acrylic resin blocks, namely, group A (pink acrylic blocks), which had Cention in cement; group B (white acrylic blocks), which has zirconomer cement; and group C (violet acrylic blocks), which had Vitremer cement. There was no statistically significant difference between the three groups and the normal distribution, as shown by the negligible values in the tests involving the three groups. Put simply, each of the three categories exhibits data that follows a normal distribution. This allows for further data analysis to be conducted using the parametric test of significance. The shear bond strength of hybrid glass ionomer restorative materials has to be further investigated in both laboratory and living organism settings.

Novel microbial synthesis of titania nanoparticles using probiotic Bacillus coagulans and its role in enhancing the microhardness of glass ionomer restorative materials

Dental caries is a commonly occurring non-communicable disease throughout the world that might compromise the quality of any individual’s life. Glass ionomer cements (GIC) are the most acceptable restorative materials due to their ease of manipulation, minimal tooth loss and least invasive strategy; however, they lack mechanical stability that has become a point of concern. Nanoparticles (NPs) are an outstanding option for modifying and enhancing the properties of dental materials. The focus of this study was to prepare novel, biocompatible titania dioxide (TiO2) NPs as a dental-restorative material using an efficient probiotic Bacillus coagulans. The prepared NPs were incorporated into glass ionomer restorative material at varying concentrations and investigated for cell viability percentage, microhardness and surface morphology. Results indicated that pure 100% anatase phase TiO2 NPs with particle size of 21.84 nm arranged in smooth, spherical agglomerates and clusters forms. These NPs depicted cell viability > 90%, thus confirming their non-cytotoxic behavior. GIC restorative materials reinforced by 5% titania (TiO2) NPs demonstrated the highest microhardness in comparison to the control group and other experimental groups of the study. Surface morphology analysis revealed a reduction in cracks in this novel dental-restorative material supporting its compatible biological nature with better hardness strength and negligible crack propagation. Overall, these results indicated that TiO2 NPs produced using a biological approach could be easily used as restorative materials in dental applications.Graphical

Clinical and Radiographic Evaluation of Different Glass Ionomer Restorative Materials in Primary Molars: A Comparative Randomized Clinical Trial.

The study aimed to evaluate and compare the clinical and radiographic success rate of Ketac Universal (3M), GC 9 EXTRA (GC), and Cention N (Ivoclar) restorative materials in primary molars. The study was conducted as randomized clinical trial in children aged 3-8 years old, out of which a total of 75 primary molars were selected in 43 patients who met the inclusion criteria. The sample size was further divided into three groups of restorative materials, which included group I-Ketac Universal (n = 25), group II-GC 9 EXTRA (n = 25), and group III-Cention N (n = 25). Class I restorations were placed randomly according to the computerized randomization in primary molars and evaluated at baseline (1 week), 6 months, and 12 months according to modified United States Public Health Service (USPHS) criteria and bitewing radiographs. On intercomparison of three groups at 12 months, there was no significant difference found, while on pairwise comparison of Ketac Universal and Cention N, there was a significant difference in relation to surface texture (p = 0.04*) and anatomic contour (p = 0.04*) at 12 months. Newly introduced restorative material Cention N exhibited improved physical and mechanical properties and can be recommended as a cost-effective restorative and easy-to-use material in posterior load-bearing primary molars. Restoration of primary teeth continues to be an important aspect of restorative dentistry. The longevity of restorations in primary teeth is significantly different for all materials compared to permanent dentition. This makes the assessment of these restorations as a separate group meaningful. Kataria VG, Patel MC, Bhatt R, et al. Clinical and Radiographic Evaluation of Different Glass Ionomer Restorative Materials in Primary Molars: A Comparative Randomized Clinical Trial. Int J Clin Pediatr Dent 2023;16(6):829-836.

Enhancing the durability and antibacterial activity of glass ionomer restorative material enriched by l-arginine and nano-titanium for pit and fissure sealing

BackgroundSealing teeth’ pits and fissures is of prime importance in preventing caries. Despite the evidenced bioactivity of glass-ionomer cements (GICs), they still fail to totally inhibit caries. This partially might be due to their insufficient antibacterial and strength properties. l-arginine (Arg) has superior caries-preventive potential thanks to its prebiotic-based biofilm-modulating effect. Titanium dioxide (TiO2) on the other hand, has well-known antibacterial characteristics, and being in nano size is supposed to improve strength. Therefore, this study aims to improve the antibacterial efficiency and the mechanical properties of conventional GICs using 1% Arg and 3% TiO2 nanoparticles for pit and fissure sealing.MethodsEtched enamel surfaces of 100 extracted human third molars were randomly divided into two groups; a control group, where teeth were restored using glass ionomer Ionofil Plus, and an experiment group, where teeth were restored using glass ionomer Ionofil Plus incorporating Arg–TiO2. Specimens of both groups were tested for microleakage, enamel shear bond strength, and fluoride ion release using a stereo microscope, universal testing machine, and ion chromatography ICs 5000+ SP respectively. Surface analysis was conducted through scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM–EDX) and atomic force microscope (AFM). Furthermore, specimens of both groups were incubated with Streptococcus mutans, Lacticaseibacillus rhamnosus, and Actinomyces viscous for quantitative antibacterial evaluation, compared to a specimen-free control using adherent/planktonic bacterial count test.ResultsThe experimental group had statistically lower microleakage percentage, higher shear bond strength, and constant fluoride release compared to the control group at P = 0.01, 0.002, and < 0.001 respectively. SEM of the experimental group revealed hybrid particles of the Arg–TiO2 incorporating GIC with clusters of uniformly distributed TiO2 nanoparticles. AFM showed lower surface roughness for the experimental group indicating its homogeneity. The adherent probiotic L. rhamnosus bacterial count had the highest count in Arg–TiO2 (IP) GIC group (P < 0.001) with lack of adherent pathogenic S. mutans bacterial count compared to planktonic/adherent S. mutans bacterial count in the control group and (IP) GIC group (P < 0.05).ConclusionsIncorporating 3% TiO2 nanoparticles and 1% Arg in GICs can enhance their mechanical properties, fluoride release, and antimicrobial efficiency.

Effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass-ionomer restorations to dentin

ObjectivesThis study was conducted to evaluate the effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass ionomer restorations to dentin. Materials and methodsConventional glass ionomer cement (Equia forte, GC Tokyo, Japan), resin-modified glass ionomer (Fuji II LC, GC Tokyo, Japan) and propolis powder (dried extract from honey bees) materials were used in this study. Both conventional glass ionomer and resin-modified glass ionomer were modified by two different concentrations of ethanolic extract of propolis (10 % and 25 % EEP). For antibacterial test, Streptococcus mutans strain was spread on agar petri dishes using a sterile swab. Discs of both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were fabricated within the agar plates. Antibacterial activity was evaluated by measuring the inhibition zones around each disc. For microshear bond strength test, 60 healthy human permanent molars were prepared by cutting occlusal surface and expose the dentin at the height of contour of all teeth then conditioned using poly acrylic acid conditioner, both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were mixed and applied on conditioned dentin surface by using tygon tube. Microshear bond strength was evaluated by the universal testing machine. ResultsTwo-way ANOVA test revealed that both glass ionomer type and different concentrations of EEP had significant effect on the antibacterial test results and microshear bond strength values (p < 0,05). Glass ionomer restorative material with 25%EEP had the highest antibacterial values whereas glass ionomer restorative material without modifications (control groups) had the lowest values. Resin-modified glass ionomer without any modification (control group) had the highest bond strength while resin-modified glass ionomer with 25%EEP had the lowest bond strength. ConclusionsIncorporation of ethanolic extract of propolis to glass ionomer restorative material increases the antibacterial effects of both conventional GIC and RMGI. Inspite of this advantage, it seems that it has deleterious effect on microshear bond strength to dentin.

Concept of a Novel Glass Ionomer Restorative Material with Improved Mechanical Properties.

The objective of this study was to transfer the concept of ductile particle reinforcement to restorative dentistry and to introduce an innovative glass ionomer material that is based on the dispersion of PEG-PU micelles. It was hypothesized that reinforcing a conventional glass ionomer in this way increases the flexural strength and fracture toughness of the material. Flexural strength and fracture toughness tests were performed with the novel reinforced and a control glass ionomer material (DMG, Hamburg, Germany) to investigate the influence of the dispersed micelles on the mechanical performance. Transmission electron microscopy was used to identify the dispersed micelles. Fracture toughness and flexural strength were measured in a 3-point-bending setup using a universal testing machine. Before performing both tests, the specimens were stored in water at 37 °C for 23 h. The fracture toughness (MPa∙m0.5) of the novel glass ionomer material (median: 0.92, IQR: 0.89-0.94) was significantly higher than that of the control material (0.77, 0.75-0.86, p = 0.0078). Significant differences were also found in the flexural strength (MPa) between the reinforced (49.7, 45.2-57.8) and control material (41.8, 40.6-43.5, p = 0.0011). Reinforcing a conventional glass ionomer with PEG-PU micelles improved the mechanical properties and may expand clinical applicability of this material class in restorative dentistry.

Evaluation of fluoride release, pH and antibacterial activity of alkasite restorative material and glass Ionomer

Purpose: This study aimed to compare the antibacterial activity, pH, and fluoride release of alkasite restorative material (Cention N) and glass ionomer restorative materials (Fuji IX GP, Fuji II LC).Materials and method: Agar diffusion test was used to determine the antibacterial activity against &lt;i&gt;Streptococcus mutans&lt;/i&gt; and &lt;i&gt;Lactobacillus casei&lt;/i&gt;. The inhibition zone was measured after 24 hours. The amount of fluoride released was measured on days 1, 3, 7, 14, 21, 28, 42, 56 and 84. The pH was measured after 1, 3, 6, 12, and 24 hours.Results: All restorative materials showed antibacterial activity. Results of the &lt;i&gt;Streptococcus mutans&lt;/i&gt;, showed the follow-ing sequence: CHX &gt; Fuji IX GP &gt; Fuji II LC &gt; Cention N (&lt;i&gt;p&lt;/i&gt;&lt;0.05). The &lt;i&gt;Lactobacillus casei&lt;/i&gt; results showed the following sequence: CHX &gt;Fuji II LC &gt; Cention N &gt; Fuji IX GP (&lt;i&gt;p&lt;/i&gt;&lt;0.05). All materials showed a continuous fluoride release; Fuji IX GP showed significantly higher fluoride release, compared with Fuji II LC and Cention N. The pH test, results showed the following sequence: Cention N &gt; Fuji IX GP &gt; Fuji II LC.Conclusion: Continuous fluoride release for 3 months and antibacterial activity was observed in Cention N as well as in glass ionomer cements. Cention N showed highest pH among all materials. Further studies are required to evaluate the properties of Cention N in clinical conditions.

Comparative Evaluation of Flexural Strength, Modulus of Elasticity, and Microleakage of Three Different Glass Ionomer Restorative Materials in Class V Preparations – An In vitro Study

Aims: Flexural strength, modulus of elasticity, and microleakage evaluation of three glass ionomer restorative materials in class V preparations. Materials and Methods: Twenty bar-shaped specimens each of Type-II glass-ionomer cement (GIC), Zirconomer and Type-IX GIC were prepared by inserting freshly mixed cements into 25 mm × 2 mm × 2 mm polyvinylacetate moulds followed by storage in artificial saliva for 24 h at 37°C. Samples were then rinsed, polished, and tested in autograph universal testing machine for flexural strength and modulus of elasticity using three-point bending test. Standardized Class V cavities in 60 extracted human premolars of dimensions 3 mm × 2 mm × 1.5 mm were prepared, divided at random into three groups of twenty each and restorations were done using Type-IX GIC, Type-II GIC, and Zirconomer. Teeth were immersed in 1%wt Rhodamine-B dye after thermocycling for 24 h, split bucco-lingually in longitudinal section and evaluated for microleakage under a stereomicroscope. Results: Flexural strength evaluation showed that Zirconomer had the highest and Type-II GIC had the lowest flexural strengths that was statistically significant (P &lt; 0.05; analysis of variance [ANOVA]-Tukey Honestly Significant Difference [HSD]). Analysis of modulus of elasticity revealed that Type-IX GIC had the highest and Type-II GIC had the lowest modulus and the difference was significant statistically (P &lt; 0.05; ANOVA-Tukey HSD). Occlusal microleakage was the highest in samples restored with Zirconomer (50% of the teeth), whereas samples restored with Type IX GIC showed no microleakage. At the gingival margins, 60% of both Type-IX GIC and Zirconomer restored samples exhibited no microleakage and 55% of Type-II GIC restored samples showed no microleakage. Conclusion: Within the limitations of this study, Type IX GIC exhibited good flexural strength, low modulus of elasticity, and least microleakage followed by Type II GIC and Zirconomer.

Universal versus Glass Ionomer –Based Adhesive: Effect on Shear Bond Strength and Micro-Morphological Analysis of Resin Modified Glass Ionomer Restorative Material /Dentin Interface

Universal versus Glass Ionomer –Based Adhesive: Effect on Shear Bond Strength and Micro-Morphological Analysis of Resin Modified Glass Ionomer Restorative Material /Dentin Interface

In vitro surface and color changes of tooth-colored restorative materials after sport and energy drink cyclic immersions.

There has not been any research conducted on surface properties and color changes from sport and energy drinks on bulk-fill resin composite, nanohybrid resin composite and glass ionomer restorative material. The aim of this in vitro study was to investigate the effect of sport and energy drinks on surface hardness, roughness and color changes of bulk-fill resin composite, nanohybrid resin composite and glass ionomer restorative material, and to also evaluate the acidity and titratable acidity of the drinks. One hundred and forty-seven specimens of each tooth-colored restorative material were prepared in a polytetrafluoroethylene mold (10mm. in diameter and 2mm. in thickness). Before immersion, baseline data of hardness, roughness, and color value were recorded. Each material was divided into 3 groups for sport drink, energy drink, and deionized water (serving as a control). The specimens were immersed in a storage agent for 5s, then in artificial saliva for 5s alternately for 24 cycles, and then stored in artificial saliva for 24h. The immersion cycle was repeated for 14days and hardness, roughness and color values were measured at 7 and 14days. After immersion, the glass ionomer restorative material had statistically less hardness, more roughness and more color changes than the others (P < 0.05). Energy drink groups statistically caused more surface and color changes than sport drink groups (P < 0.05). Sport and energy drinks affected hardness, roughness, and color changes in all the tooth-colored restorative materials evaluated.

Evaluation of a Method to Determine Wear Resistance of Class I Tooth Restorations during Cyclic Loading.

The aim of this study was the development of a test regime to determine the wear resistance and predict the clinical performance of conventional glass ionomer cement (GIC) restorations in Class I tooth cavities. Cavities were prepared in excised human teeth and restored using three conventional glass ionomer restorative materials: DeltaFil, Fuji IX GP and Ketac Universal. The restored teeth were mechanically and thermally stressed using a chewing simulator with a maximum number of 1,200,000 load cycles. Besides determining the number of cycles achieved, the abrasion volume after termination of the chewing simulation was calculated using µCT images. All teeth restored with DeltaFil reached 1,200,000 cycles without any restoration failure. Only 37.5% of the restorations each with Ketac Universal and Fuji IX GP were able to achieve the maximum cycle number. A significant lower abrasion volume for restorations with DeltaFil compared to Ketac Universal (p = 0.0099) and Fuji IX GP (p = 0.0005) was found. Laboratory chewing simulations are a useful tool to study basic wear mechanisms in a controlled setting with in-vivo related parameters. DeltaFil shows an improved wear resistance compared to other conventional GICs, indicating the high potential of this material for long-lasting Class I restorations.

Fracture Toughness, Hardness, and Microstructure of Ceramic Modified Versus Resin Modified Glass Ionomer Restorative Materials

The aim of this study was evaluation and comparison of fracture toughness, hardness and microstructure of ceramic-modified versus resin-modified glass ionomer restorative materials. For fracture toughness, 20 specimens from both materials were fabricated in a stainless-steel split mold (25mm length, 2.5mm thickness and 5mm width). Fracture toughness was measured using Lloyd universal testing machine with cross head speed 2 mm/min. For hardness testing, 20 specimens from both materials were fabricated in a disc-shaped stainless-steel mold (5mm diameter and 2mm height). All specimens were stored in distilled water at 37°C for 24 hours. Hardness was measured using Vickers micro hardness tester with 50 g load. The microstructure of both materials was examined using scanning electron microscopy. The results of this study showed there wasn’t significant difference between both materials in fracture toughness. The hardness of ceramic-modified glass ionomer was higher than that of the resin-modified type. The addition of ceramic filler to the glass ionomer didn’t improve its fracture toughness. The microstructure of resin-modified glass ionomer showed tight packing between the matrix and the resin filler, while the ceramic-modified glass ionomer showed separated matrix from the ceramic filler.

Comparative Evaluation of Water Sorption, Solubility, and Microhardness of Zirconia-reinforced Glass Ionomer, Resin-modified Glass Ionomer, and Type IX Glass Ionomer Restorative Materials: An In Vitro Study.

The study aimed to evaluate and compare water sorption, solubility, and microhardness of zirconia-reinforced glass ionomer, resin-modified glass ionomer, type IX glass ionomer cements. 90 specimens were prepared in total of which 45 cylindrical specimens with dimensions of (6 × 4) mm and 45 disks with (10 × 2) mm were prepared from Zirconomer, RMGIC, and Type IX GIC restorative materials, each material having 30 specimens (15 disks, 15 cylinders). After taking the initial weight (W1), the 45 cylinders (15 of each material) were immersed in artificial saliva at 37°C for 28 days after which the weights W2 and W3 were weighed. The other 45 disks (15 of each material) were subjected to microhardness test under microhardness tester. Results were subjected to ANOVA and Tuckey's post hoc test. Zirconomer showed the maximum resistance to water sorption and solubility followed by RMGIC and type IX GIC with a significant p value of < 0.001 difference. For microhardness, Zirconomer showed the highest value with a significant p value of < 0.001 difference. But, there was no significant difference between RMGIC and Type IX GIC depicting almost equal strength. Water sorption, solubility, and microhardness of Zirconomer were significantly high in comparison to the other groups and it can be used as a posterior restorative material for stress-bearing areas. As pediatric dentistry demands restorations to be completed frequently in less than ideal conditions, Zirconomer has shown to be better than RMGIC and conventional GIC probably because of the improvisation in the GIC properties. Bethapudy DR, Bhat C, Lakade L, et al. Comparative Evaluation of Water Sorption, Solubility, and Microhardness of Zirconia-reinforced Glass Ionomer, Resin-modified Glass Ionomer, and Type IX Glass Ionomer Restorative Materials: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(2):175-181.

Scan Electron Microscope Evaluation of Marginal Adaptation of Alkasite, Bulk-fil Resin Composite, Resin Modified Glass Ionomer, and High Viscosity Glass Ionomer Restorative Materials

Scan Electron Microscope Evaluation of Marginal Adaptation of Alkasite, Bulk-fil Resin Composite, Resin Modified Glass Ionomer, and High Viscosity Glass Ionomer Restorative Materials

Long-Term Water Balance Evaluation in Glass Ionomer Restorative Materials.

The complex role of water in glass ionomer cement (polyalkenoate) dental restorative materials has been studied, but much of the present understanding concerning water balance within these materials is based on very early studies and short-term experiments. This study evaluated the nature of the water species of six conventional and four resin modified glass ionomer restorative materials over 3 years using thermogravimetric analysis techniques. Materials were prepared, placed in crucibles, and stored in physiologic phosphate buffered saline and evaluated at 24 h, 1 week, and then at 1, 3, 6, 9, 12, 18, 24, 30 and 36 months. All materials demonstrated a significant increase in unbound water percentage content but except for the resin modified materials, the enthalpy required to remove the unbound water species did not significantly change over 36 months. Also, bound water content percentage and removal enthalpy was established at 24 h, as no significant increase was noted in both bound water content and removal enthalpy over the course of this evaluation. This study suggests that unbound water species may increase with time and is loosely held except for the resin modified materials. Protective coatings placement and re-evaluation are prudent to prevent unbound water loss.

Meta-Analysis of In-Vitro Bonding of Glass-Ionomer Restorative Materials to Primary Teeth.

Restoration of primary teeth is among the main clinical applications of glass-ionomer cements (GIC). The aim of the study was to review and summarize existing evidence of in vitro bond strength of glass-ionomer (GI) restoratives to enamel and dentin of primary teeth. A literature search was performed in PubMed/Medline, Scopus, Web of Science, Cochrane, and Google Scholar databases to identify studies published until April 2021. The search strategy was: (“glass”) and (“ionomer”) and (“primary” or “deciduous”) and (“bond” or “tensile” or “shear”). Two researchers independently retrieved articles that reported on the bond strength of GIC to primary dentin and/or enamel. The meta-analysis was performed to compare the bond strength values of conventional (C) GIC and resin-modified (RM) GIC to different substrates. From 831 potentially eligible articles, 30 were selected for the full-text examination, and 7 were included in the analysis. Studies were rated at high (3), medium (3), and low (1) risk of bias. RM-GIC showed higher bond strength to primary enamel and dentin compared to the C-GIC. Meta-analysis of in vitro studies, evaluating bonding properties of GI restoratives to primary teeth, suggests the superior performance of RM-GIC. However, there is a lack of studies that examine the properties of novel GI formulations.

Influence of Surface Resin Coating on Bio-Compatibility and Attaching ability of Human Gingival Cells to the Glass-Ionomer Restorative Material

Background and objective. Glass-Ionomer (G.I.) restoratives are used to manage cervical tooth defects; however certain chemicals could leach out of the material and affect the adjacent gingival tissue. Therefore, this study aimed to assess the viability and attachment of human gingival epithelial cells (HGECs) on both resin-coated and uncoated Equia fil G.I. restorative materials. Materials and Methods. Two groups of G.I. disc specimens (n= 34 each) were constructed from Equia fil G.I. restorative by mixing the content of G.I. capsules, then injection into silicone molds, the material was left for setting before cutting the excess. Surfaces of group I specimens were coated with the accompanied protective Equia resin, while those in group II were left uncoated. HGECs were isolated and incubated with the constructed specimens. The cell viability was then assessed using both Methyl Tetrazolium (MTT) and Trypan blue dye exclusion (TBDE) assays. The micromorphology and the attaching ability of the isolated cells to specimens’ surfaces were assessed using SEM. The surface roughness was measured and the chemical analysis of G.I. surfaces was also analyzed by energy disperse x-ray. Results. Reduction in HGECs viability was noticed in contact with G.I. of both test groups. However, HGECs showed better viability and attaching ability to the resin-coated G.I. surface than were in presence of uncoated restorative. Conclusion. Resin Coating preserves the cell viability and improves the attachment of HGECs on Equia fil G.I restorative surfaces. This finding, therefore, offers sound evidence to select such material in treating sub-gingival cervical tooth defects.

Clinical evaluation of two glass ionomer restorative materials in class I cavities

Aim To evaluate the clinical performance of two glass ionomer restorative materials (EQUIA Forte Fil and IonoStar Molar) and a nanohybrid composite (Tetric EvoCeram) in class I cavities over 1 year. Patients and methods Twenty patients of age 25–40 years received 60 restorations. Each patient received three different restorations representing the tested materials. Class I cavity was prepared according to the caries extension. All the materials were applied following the manufacturer's instructions. Finishing and polishing was performed using finishing burs and polishing discs. Each restoration was evaluated clinically at baseline (24 h), 6 months and after 1 year using modified USPHS. Results The recall rate was 100% after 1 year. The alpha rating for retention and restoration fracture for EQUIA Forte Fil were 95%, IonoStar Molar 85%, Tetric EvoCeram 100% alpha ratings. For marginal discoloration for EQUIA Forte Fil were 95%, IonoStar Molar 80%, Tetric EvoCeram 95% alpha ratings. For marginal adaptation for EQUIA Forte Fil were 90%, IonoStar Molar 80%, Tetric EvoCeram 90% alpha ratings. For anatomic form for EQUIA Forte Fil 95%, IonoStar Molar 75%, Tetric EvoCeram 95% alpha ratings. For color match for EQUIA Forte Fil 85%, IonoStar Molar 80%, Tetric EvoCeram 90% alpha ratings. For surface texture for EQUIA Forte Fil 85%, IonoStar Molar 90%, Tetric EvoCeram 95% alpha ratings. For secondary caries for EQUIA Forte Fil 95%, IonoStar Molar 85%, Tetric EvoCeram 100% alpha ratings. Using χ2 test, there was no statistically significant difference between the tested groups for marginal discoloration, marginal adaptation, anatomic form, color match, and surface texture (P Conclusion EQUIA Forte Fil Glass ionomer achieved clinically superior results after 1 year of service. IonoStar Molar Glass ionomer also achieved acceptable results. Tetric EvoCeram composite achieved superior clinical results for all criteria of the evaluation. A longer evaluation period may be recommended to decide the use of these materials safely in class I cavities.