Resin-modified Glass Ionomer Cement Research Articles

A study of the cytotoxicity of resin-modified glass-ionomer cement

A study of the cytotoxicity of resin-modified glass-ionomer cement

Antibacterial, cytotoxic and mechanical properties of a orthodontic cement wiht phosphate nano-sized and phosphorylated chitosan: an in vitro study

ObjectivesEvaluate, in vitro, the effect of incorporating nano-sized sodium trimetaphosphate (TMPnano) and phosphorylated chitosan (Chi-Ph) into resin-modified glass ionomer cement (RMGIC) used for orthodontic bracket cementation, on mechanical, fluoride release, antimicrobial and cytotoxic properties. MethodsRMGIC was combined with Chi-Ph (0.25%/0.5%) and/or TMPnano (14%). The diametral compressive/tensile strength (DCS/TS), surface hardness (SH) and degree of conversion (%DC) were determined. For fluoride (F) release, samples were immersed in des/remineralizing solutions. Antimicrobial/antibiofilm activity was evaluated by the agar diffusion test and biofilm metabolism (XTT). Cytotoxicity in fibroblasts was assessed with the resazurin method. ResultsAfter 24 hours, the RMGIC-14%TMPnano group showed a lower TS value (p<0.001); after 7 days the RMGIC-14%TMPnano-0.25%Chi-Ph group showed the highest value (p<0.001). For DCS, the RMGIC group (24 hours) showed the highest value (p<0.001); after 7 days, the highest value was observed for the RMGIC-14%TMPnano-0.25%Chi-Ph (p<0.001). RMGIC-14%TMPnano, RMGIC-14%TMPnano-0.25%Chi-Ph, RMGIC-14%TMPnano-0.5%Chi-Ph showed higher and similar release of F (p > 0.001). In the SH, the RMGIC-0.25%Chi-Ph; RMGIC-0.5%Chi-Ph; RMGIC-14%TMPnano-0.5%Chi-Ph groups showed similar results after 7 days (p>0.001). The RMGIC-14%TMPnano-0.25%Chi-Ph group showed a better effect on microbial/antibiofilm growth, and the highest efficacy on cell viability (p<0.001). After 72 hours, only the RMGIC-14%TMPnano-0.25%Chi-Ph group showed cell viability (p<0.001). ConclusionThe RMGIC-14%TMPnano-0.25%Chi-Ph did not alter the physical-mechanical properties, was not toxic to fibroblasts and reduced the viability and metabolism of S. mutans. Clinical relevanceThe addition of phosphorylated chitosan and organic phosphate to RMGIC could provide an antibiofilm and remineralizing effect on the tooth enamel of orthodontic patients, who are prone to a high cariogenic challenge due to fluctuations in oral pH and progression of carious lesions.

Effect of Luting Materials on the Accuracy of Fit of Zirconia Copings: A Non-Destructive Digital Analysis Method.

The marginal accuracy of fit between prosthetic restorations and abutment teeth represents an essential aspect with regard to long-term clinical success. Since the final gap is also influenced by the luting techniques and materials applied, this study analyzed the accuracy of the fit of single-tooth zirconia copings before and after cementation using different luting materials. Forty plaster dies with a corresponding zirconia coping were manufactured based on a single tooth chamfer preparation. The copings were luted on the plaster dies (n = 10 per luting material) with a zinc phosphate (A), glass-ionomer (B), self-adhesive resin (C), or resin-modified glass-ionomer cement (D). The accuracy of fit for each coping was assessed using a non-destructive digital method. Intragroup statistical analysis was conducted using Wilcoxon signed rank tests and intergroup analysis by Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Accuracy of fit was significantly different before/after cementation within A (0.033/0.110 µm) and B (0.035/0.118 µm; p = 0.002). A had a significantly increased marginal gap compared to C and D, and B compared to C and D (p ≤ 0.001). Significantly increased vertical discrepancies between A and B versus C and D (p < 0.001) were assessed. Of the materials under investigation, the zinc phosphate cement led to increased vertical marginal discrepancies, whereas the self-adhesive resin cement did not influence the restoration fit.

Micro-shear bond strength of a novel resin-modified glass ionomer luting cement (eRMGIC) functionalized with organophosphorus monomer to different dental substrates

ObjectivesThis study aims to assess and compare the micro-shear bond strength (μSBS) of a novel resin-modified glass-ionomer luting cement functionalized with a methacrylate co-monomer containing a phosphoric acid group, 30 wt% 2-(methacryloxy) ethyl phosphate (2-MEP), with different substrates (dentin, enamel, zirconia, and base metal alloy). This assessment is conducted in comparison with conventional resin-modified glass ionomer cement and self-adhesive resin cement. Materials and methodsIn this in vitro study, ninety-six specimens were prepared and categorized into four groups: enamel (A), dentin (B), zirconia (C), and base metal alloys (D). Enamel (E) and dentin (D) specimens were obtained from 30 human maxillary first premolars extracted during orthodontic treatment. For zirconia and metal alloys, 48 disks were manufactured using IPS e.max ZirCAD through dry milling and Co–Cr powder alloy by selective laser milling. Each group was further subdivided into three subgroups (n = 8) according to the luting cement used: (1) Fuji PLUS resin-modified glass ionomer luting cement (FP) as a control cement, (2) modified control cement (eRMGIC), and (3) RelyX U 200 (RU 200) self-adhesive resin cement. The two-way analysis of variance and Tukey's HSD were used to assess the data obtained from measuring the μSBS of the samples. ResultsThe results of this study showed that the mean μSBS values of eRMGIC were statistically higher compared to FP in all tested groups (p < 0.001). The mean μSBS results of eRMGIC were non-significantly different from those recorded by RU 200 for all substrates except for the dentin substrate, where the RU200 cement produced significantly higher strength (p < 0.001). The failure modes were limited to a combination of mixed and adhesive failures without pure cohesive failure. SignificanceThe functionalization of FP with an organophosphorus co-monomer (2-MEP) directly affects the adhesion performance of the functionalized cement, which may be utilized to develop a new type of acid-base cement. It exhibited a performance comparable to that of resin-based cement and should serve well under different clinical conditions.

EVALUATION OF STAINLESS-STEEL CROWN CEMENTED WITH GLASS IONOMER CEMENT, RESIN MODIFIED GLASS IONOMER CEMENT AND NEW SELF-ADHESIVE RESIN CEMENT: AN INVITRO STUDY

Aim: To assess and compare the retentive strength of stainless-steel crown cemented with glass ionomer cement (GC Fuji I), resin modiifed glass ionomer cement (Relyx Luting 2) and new self-adhesive resin cement (RelyX U200). Materials and Method: Forty-five extracted primary teeth were mounted on acrylic blocks. Stainless steel crowns were selected for each tooth. Three cements compared in this in vitro study were glass ionomer cement (GC Fuji I), resin modified glass ionomer cement (RelyX Luting2) and self-adhesive resin cement (RelyX U200). Teeth were randomly divided into three groups of 15 samples each. Retentive strength was tested using Instron Universal testing machine. The retentive strength values were recorded and calculated by the formula: Load/Area. Results: RelyX U200 (Self-adhesive resin cement) showed significantly higher retentive strength than rest of the two cements. No significant difference was found between RelyX Luting 2 (Resin modified glass ionomer cement) and GC Fuji I (Glass ionomer cement). Conclusion: The finding of our study suggests that self-adhesive resin cement was better than resin modified glass ionomer cement and glass ionomer cement. RelyX U200 (Self-adhesive resin cement) can be used for the cementation of stainless-steel crowns.

Evaluation of the Effect of Different Bonding Systems and Restorative Materials on Shear Bond Strength in the Repair of High-Viscosity Glass Ionomer Cement

Aim: High viscosity glass ionomer cements have been produced to increase the mechanical properties of glass ionomer cements. The aim of this study is to determine the appropriate adhesive system and restorative material that can be used in fracture repair of high viscosity glass ionomer cements. Material and Methods: A total of 140 standard size acrylic blocks were used in the study. 14 groups were formed from randomly selected acrylic blocks, with 10 samples in each group. High viscosity glass iomomer cement was placed in the first 13 groups, and resin-modified glass ionomer cement was placed in the last group. After the thermal cycle aging process was applied to all samples, repair restorations were performed with 4 different adhesive systems, 2 different composite resins and 2 different restorative types of glass ionomer cement. After the repair restorations, thermal cycle aging was applied again and the shear bond strengths were evaluated. One-way analysis of variance and Duncan multiple comparison test were used for statistical analysis. Results: The highest shear bond strength values were obtained by the total etch adhesive system (p&lt;0.001). The lowest shear bond strength values were obtained when high-viscosity glass-iomomer cement without adhesive system was restored with high-viscosity glass iomomer cement (p&lt;0.001). Conclusion: For higher shear bond strength values in the repair of high-viscosity glass ionomer cements should use to total etch adhesive systems and composite resin.

Effect of various surface coating methods on surface roughness, micromorphological analysis and fluoride release from contemporary glass ionomer restorations.

To evaluate the effect of various surface coating methods on surface roughness, micromorphological analysis and fluoride release from contemporary resin-modified and conventional glass ionomer restorations. A total of 72 permanent human molars were used in this study. The teeth were randomly assigned into 2 groups according to type of restorative materials used; resin modified glass ionomer cement and conventional glass ionomer (SDI Limited. Bayswater Victoria, Australia). Each group was subdivided into 3 subgroups according to the application of coat material; Sub-group1: without application of coat; Sub-group2: manufacturer recommended coat was applied and sub-group3: customized (vaseline) coat was applied. Each group was then subdivided into two divisions according to the time of testing; immediate (after 24h) and delayed (after 6 months of storage). Three specimens from each sub-group were selected for surface roughness test (AFM) and another 3 specimens for the micromorphological analysis using scanning electron microscope (SEM). For the fluoride release test, a total of 60 cylindrical discs were used (n = 60). The discs were randomly split into 2 groups according to type of restorative materials used (n = 30); resin modified glass ionomer cement and conventional glass ionomer. Each group was subdivided into 3 subgroups (n = 10) according to the application of the coat material; Sub-group1: without application of coat; Sub-group2: with the manufacturer recommended coat and sub-group3: with application of customized (vaseline) coat. Data for each test was then collected, tabulated, were collected, tabulated, and tested for the normality with Shapiro-Wilk test. Based on the outcome of normality test, the significant effects of variables were assessed using appropriate statistical analysis testing methods. Regarding the data obtained from surface roughness test, Shapiro-Wilk test showed normal distribution pattern of all values (p > 0.05). Accordingly, Two-way ANOVA outcome showed that the 'type of restoration' or 'test time' had statistically significant effect on the AFM test (p < 0.05). Regarding Fluoride specific ion electrode test 2-way ANOVA followed by Least Significant Difference (LSD) Post-hoc test revealed significant difference among the groups (p < 0.05). It showed that SDI GIC group after 14 days of measurement had the highest mean of fluoride release (36.38 ± 3.16 PPM) and SDI RMGIC after 30 days of measurement had the second highest mean of fluoride release (43.28 ± 1.89 PPM). Finally, regarding the micromorphological analysis using SEM, a slight difference was observed between the studied groups. Based on the results of this study, various coatings enhance surface roughness in the initial 24h of restoration insertion. Different coat types seems that have no influence on fluoride release and the micromorphological features of the restoration/dentin interface.

Bond Integrity and Microleakage of Orthodontic Bands Cemented by Glass Ionomer Cements Stored in Static Magnetic Field

Aim: Improving the band-tooth bond integrity by glass ionomer cement (GIC) is essential in orthodontic treatments. As, microleakage under bands induced enamel demineralization. Storing the dental material to updated magnets improved their mechanical properties. This research aimed to assess the microleakage of GIC after storing in a static magnetic field (SMF). Material and Methods: Forty premolars and their suitable bands were randomly classified into two main groups according to the types of GIC tested in this research; resin-modified GIC (RMGIC) and conventional GIC (CGIC). Each group was subdivided according to the exposure to SMF before polymerization into two subgroups. CGIC not exposed to SMF (CC), CGIC exposed to SMF (CM), RMGIC not exposed to SMF (LC) and RMGIC exposed to SMF (LM). SMF intensity performed was 0.225 Tesla, exposed for 48 hours at room temperature. The entire tube of RMGIC was inserted in SMF, where the powder of CGIC was stored in SMF. The microleakage under the band was evaluated under a 20× stereomicroscope by dye penetration technique at the cement band interface. Wilcoxon signed-rank test was used for data analysis, p ≤ .05. Results: The main (SD) microleakage of GIC reduced significantly ( p = .043) after being exposed to SMF from 3.1950 (0.632) mm to 1.7095 (0.1176) mm and from 0.8745 (0.1104) mm to 0.6430(0.094) mm for CGIC and RMGIC, respectively. Conclusion: Storing the CGIC powder in (0.225 T) SMF improves band-tooth bond integrity. Additionally, the preservation of RMGIC in SMF minimized the microleakage under orthodontic bands.

Tensile bond strength between paediatric prefabricated zirconia crowns and primary maxillary incisors when using various types of luting cements: an in vitro study.

There is limited evidence regarding the most appropriate type of luting cement for paediatric prefabricated zirconia crowns (PZCs) in primary maxillary incisors. The retention of PZCs is dependent on the bond strength of luting cement between PZCs and primary maxillary incisors. The aim of this study was to evaluate the tensile bond strengths between PZCs and primary maxillary incisors with different types of luting cements. Thirty freshly extracted human primary maxillary incisors were prepared and randomly divided into three groups corresponding to three luting cements: bioactive cement, resin cement, and resin-modified glass ionomer cement (RMGIC), and then restored with PZCs. Tensile bond strengths were evaluated by a universal testing machine. The results were analysed using one-way ANOVA with Tukey's post-hoc test (p < 0.05). The means of the tensile bond strengths were 1.43 ± 0.85 MPa, 0.91 ± 0.63 MPa, and 0.56 ± 0.39 MPa for the bioactive cement, resin cement, and RMGIC groups, respectively. A significant difference in tensile bond strength was observed between the bioactive cement and the RMGIC group (p < 0.05) but there was no significant difference in tensile bond strength between the resin cement group and the others. Types of luting cement influenced the tensile bond strength between PZCs and primary maxillary incisors. The bioactive cement showed higher tensile bond strength than the resin cement and RMGIC.

Effect of bonding pericervical dentin with reinforcing materials on strength of root-filled mandibular single-canal premolars: An in vitro study

ABSTRACT Aim: The present study examined the effect of bonding the pericervical dentin using resin-modified glass-ionomer cement (RMGIC), nanohybrid composite (Endure Nano), and Biodentine on the fracture resistance of root-filled mandibular premolars. Methods: Twenty-four human single-rooted mandibular premolars were decoronated, cleaned, and shaped with ProTaper Universal till size F3. The roots were obturated with gutta-percha using a single-cone technique. The teeth were randomly grouped into four groups of n = 6 each. After removing the 3 mm coronal gutta-percha in Groups I, II, and III, the intra-orifice barriers of RMGIC, nanohybrid composite (Endure Nano), and Biodentine were placed, respectively. Group IV served as the control. The fracture resistance of the specimens was analyzed using the universal testing machine. The derived data were statistically evaluated using one-way ANOVA and post hoc Tukey’s honestly significant difference test. Results: A significantly high fracture strength was exhibited by specimens of Group I, followed by Groups II and III, respectively. The lowest fracture strength was shown by the control group. Conclusion: Within the limitation of the present study, the fracture resistance of an endodontically treated tooth was significantly influenced by the type of intra-orifice barrier.

Cytotoxic effect of dental luting cement on human gingival mesenchymal stem cell and evaluation of cytokines and growth factor release - An in vitro study.

In routine dental care, various dental luting cements are utilized to cement the dental prosthesis. Thus, the aim of the current study was to assess the Cytotoxic effect of three different dental luting cements on human gingival mesenchymal stem cell and evaluation of cytokines and growth factors release. Cytotoxicity of glass ionomer cement (GIC), resin modified glass ionomer cement (RMGIC) and resin cement (RC) on the human gingival mesenchymal stem cells (HGMSCs) was evaluated. Amongst the cements tested, least cytotoxic cement was further tested for the release of cytokines and growth factors. MTT test was used to evaluate the cytotoxicity of the dental luting cements at 1 h, 24 h, and 48 h on HGMSCs. Cytokines such as interleukin (IL) 1α & IL 8 and growth factors such as platelet derived growth factor & transforming growth factor beta release from the least cytotoxic RC was evaluated using flow cytometry analysis. The mean absorbance values by MTT assay and cell viability at various time intervals between four groups were compared using a one way analysis of variance test and Tukey's post hoc test. The least cytotoxic RC group and the control group's mean levels of cytokines and growth factors were compared using the Mann-Whitney test. As exposure time increased, the dental luting cement examined in this study were cytotoxic. RC was the least cytotoxic, RMGIC was moderate and glass ionomer cement showed the highest cytotoxic effect. Concomitantly, a significant positive biological response of gingival mesenchymal stem cells with the release of ILs when exposed to the RC was observed. For a fixed dental prosthesis to be clinically successful over the long term, it is imperative that the biocompatibility of the luting cement be taken into account in order to maintain a healthy periodontium surrounding the restoration.

Comparing Zirconium Crown Marginal Adaptation in Preparations with Two Different Occlusal Reductions.

This study aimed to assess and contrast the effects on the vertical marginal fit of full contour CAD/CAM-generated monolithic zirconia crowns at pre- and post-cementation levels with various occlusal reduction schemes (planar and flat) and cements. Forty sound human maxillary first premolars were sampled for this study. The samples were divided into two main groups with twenty samples in each group according to the occlusal reduction scheme as follows: Group A included a chamfer finishing line design with a planar occlusal reduction scheme and Group B included a chamfer finishing line design with a flat occlusal reduction scheme. Each group was sampled into two subgroups (n = 10) based on the type of cement as follows: resin-modified glass ionomer cement (Fuji Plus) for subgroups A1 and B1, and a universal adhesive system (Duo Estecem II) for subgroups A2 and B2. Marginal gaps were tested in four indentations using a Dino light stereomicroscope (230×). Paired T-tests and Student's t-tests were used to analyze the data. Before cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, while subgroup B2 scored the highest mean; following cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, and subgroup B2 scored the highest mean of vertical marginal gap values. A chamfer finishing line design with a planar occlusal reduction scheme could be a preferable occlusal reduction scheme.

Evaluation of Enamel Staining Susceptibility after Using Three Kinds of Orthodontic Adhesives and Four Different Clean-Up Techniques

Background: The present study tried to find the proper bonding and debonding technique to preserve the natural enamel surface and avoid its discoloration. Methods: Sixty newly extracted human premolars were randomly divided into three groups, and three orthodontic adhesives were applied to bond the brackets: chemically cured System 1 Plus adhesive (Ormco, USA) (CC), light-cured resin (Transbond XT, 3Munitek, USA) (LC), and resin-modified glass ionomer cement (Fuji Japan) (GI). The specimens were immersed in black tea for one week and debonded, and four prophylactic methods were applied to remove residual resin: 1) tungsten carbide bur (TC), 2) tungsten carbide bur + Sof-Lex polisher (TC + SL), 3) tungsten carbide bur + One Gloss Polisher (TC + OG), and 4) tungsten carbide bur + Po-Go polisher (TC + PG). The enamel color was measured according to the CIE standard system (Commission Internationale de l’Eclairage) by Konica Minolta CS Spectroradiometer equipment twice: 1) natural enamel color before bonding and 2) after bonding, staining, debonding, and polishing. The ΔE value is the tooth discoloration, which is measured from the mean Δa*, Δb*, and ΔL* values using the following formula ΔE = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1/2 for each group. Then, it was statistically analyzed using a t-test. Results and Conclusions: Regarding adhesive materials, CC adhesive showed higher discoloration than LC in all the polishing methods. The lowest discoloration was observed in GI. The highest ΔE* values were obtained using TC only, which was deemed insufficient to remove the residual adhesives. Applying TC + Sof-Lex and TC + PoGo equally enhanced the results; therefore, they were the best polishing methods.

Comparison of Three Different Orthodontic Adhesives Bonded to Metallic and Ceramic Brackets: SEM and SEM/EDX Analysis (In Vitro Study).

To compare three different orthodontic adhesives (Transbond XT Light Cure Adhesive, Heliosit Orthodontic, Fuji Ortho LC) bonded to two types of orthodontic brackets: ceramic brackets (Fascination Roth 0.22) and metallic brackets (Topic Roth 0.22, Dentaurum). The study was performed on 18 human teeth (6 for each adhesive). The prepared teeth were divided into three groups according to the examination time. Subsequently, they were observed after 1, 2 and 3 weeks following bonding. After the experimental procedure, the teeth samples were cut in half along the longitudinal axis in the vestibulo-oral direction, fixed with conductive carbon cement, placed in a high-vacuum evaporator and then coated with carbon. One half of each sample was observed under a Field-emission gun scanning electron microscope (FEG-SEM Hitachi SU 8030, Japan), while on the second half of the samples qualitative (X-ray line-scans) and semi-quantitative point X-ray energy dispersive analyses (EDX) were performed with Thermo Noran (USA) NSS System 7, equipped with Ultra Dry detector (30 mm2 window). Transbond XT had an ideal bond with the enamel and the bracket base, with rare presence of microgaps and cracks in the enamel. Heliosit Orthodontic demonstrated a better bond relationship with the bracket base than the enamel, whereas in the latter the presence of microgaps in the bond was observed. The microphotographs of Fuji Ortho LC demonstrated many cracks inside the adhesive, and some of them continued to move forward into the enamel surface. Therefore, an impression of a very solid bond relationship with the enamel exists, with cracks being present in the enamel surface and never at the enamel-adhesive interface. Microgaps also appeared at the bracket-adhesive interface. Transbond XT is a highly filled composite resin and is an ideal orthodontic adhesive in each aspect examined, with an ideal enamel-adhesive and bracket-adhesive interface. Heliosit Orthodontic provides better bracket-adhesive interface compared to the enamel. Fuji Ortho LC as a solid resin-modified GIC provides a better enamel-adhesive interface, compared to the bracket base.

Shear bond strength between conventional composite resin and alkasite-based restoration used in sandwich technique: An in vitro study

Abstract Aim: The success of layered restorations necessitates the utilization of an improved restorative material compatible with composite restorations. Therefore, in this line of research, the strength of adhesion of conventional resin-based dental composite to different filling materials was tested. Materials and Methods: Conventional composite resin was bonded to four restorative materials (Group I: conventional glass ionomer cement (GIC), Group II: resin-modified glass ionomer cement, Group III: flowable composite, and Group IV: Cention-N) received no surface treatment (Subgroup A: control), sandblasting using 50-µm aluminum oxide particles (Subgroup B), sandblasting and resin adhesive (Subgroup C), acid etch and resin adhesive (Subgroup D), or self-etch resin adhesive (Subgroup E). After 24 h, the strength of adhesion between the conventional composite resin and the other tested filling materials was estimated by using a universal testing machine and compared using one-factor analysis of variance and Tukey’s method. Results: The conventional GIC had the minimum values of adhesion strength while the flowable composite and Cention-N had the maximum values of adhesion strength (P &lt; 0.05). The treatment of the used restorative materials with sandblasting and resin adhesive boosted the adhesion strength (P &lt; 0.05). The surface treatment of GIC-based materials with either acid etch and resin bonding agent or self-etch resin bonding agent boosted the adhesion strength (P &lt; 0.05). Conclusion: Cention-N sandblasted and coated with resin adhesive before the application of conventional composite resin in layered restorations is a potential alternative to GIC-based restorations and flowable composite.

Mechanical Properties and Ion Release from Fibre-Reinforced Glass Ionomer Cement.

The aim of this study was to compare the mechanical properties and ion release from a commercially available resin-modified glass ionomer cement to a formulation reinforced by the addition of short glass fibres at various percentages. Methods: Three experimental groups were prepared by adding a mass ratio of 10%, 15% and 20% of short glass fibres to the powder portion of the cement from a capsule (GC Fuji II LC), while the control group contained no fibres. Microhardness (n = 12), fracture toughness, and flexural, compressive and diametral tensile strength (n = 8) were evaluated. To study ion release, readings were obtained utilising fluoro-selective and calcium-selective electrodes after 24 h, 7 days and 30 days (n = 12). The spatial distribution of fibres within the material was evaluated through scanning electron microscopy. The data were analysed using one-way ANOVA with a Bonferroni adjustment. Results: The findings suggest that elevating fibre weight ratios to 20 wt% results in improved mechanical properties (p < 0.05) in microhardness, flexural strength, diametral tensile strength and fracture toughness. In terms of ion release, a statistically significant difference (p < 0.001) was observed between the groups at the conclusion of 24 h and 7 days, when the fluoride release was much higher in the control group. However, after 30 days, no significant distinction among the groups was identified (p > 0.05). Regarding calcium release, no statistically significant differences were observed among the groups at any of the evaluated time points (p > 0.05). SEM showed the fibres were homogeneously incorporated into the cement in all experimental groups. Conclusions: Resin-modified glass ionomer enhanced with short glass fibres at a weight loading of 20% showcased the most favourable mechanical properties while concurrently maintaining the ability to release fluoride and calcium after a 30-day period.

Comparative Evaluation of the Microleakage of Glass Ionomers as Restorative Materials: A Systematic Review of In Vitro Studies

This study aimed to perform a qualitative synthesis of the available in vitro evidence on the microleakage of commercially available conventional glass ionomer cements (GICs), resin-modified glass ionomer cements (RMGICs), and modified glass ionomer cements with nano-fillers, zirconia, or bioactive glasses. A systematic review was conducted according to the PRISMA 2020 (Preferred Reporting Items for Systematic Review and Meta-Analysis) statement standards. The literature search was performed in Medline (via PubMed), Embase, Web of Science, and Scopus to identify relevant articles. Laboratory studies that evaluated microleakage of GICs, RMGICs, and modified glass ionomer cements with nano-fillers, zirconia, or bioactive glasses were eligible for inclusion. The QUIN risk of bias tool for the assessment of in vitro studies conducted in dentistry was used. After the study selection process, which included duplicate removal, title and abstract screening, and full-text assessment, 15 studies were included. A qualitative synthesis of the evidence is presented, including author data, year of publication, glass ionomer materials used, sample characteristics, microleakage technique and values, and main outcome measures for primary and permanent teeth. Although no statistically significant differences were found in numerous studies, most results showed that RMGICs exhibited less leakage than conventional GICs. All studies agreed that leakage was significantly higher at dentin margins. It was also higher at the gingival margin than at the occlusal margin. Nano-filled RMGICs Ketac N100, Equia Forte, and Zirconomer appear to have less microleakage than conventional GICs and RMGICs. Further investigations using a standardized procedure are needed to confirm the results.

Shear Bond Strength of Resin-modified Glass Ionomer Cement to Primary Teeth Dentin Pretreated with Silver Diamine Fluoride and Sodium Fluoride Varnish: An In Vitro Study

Shear Bond Strength of Resin-modified Glass Ionomer Cement to Primary Teeth Dentin Pretreated with Silver Diamine Fluoride and Sodium Fluoride Varnish: An In Vitro Study

Effect of ionizing radiation on the mechanical properties of current fluoride-releasing materials.

This study aimed to evaluate the effect of fractional radiation on the mechanical properties of fluoride-releasing materials. High-viscosity glass ionomer cement (F9), resin-modified glass ionomer cement (F2), glass hybrid restoration (EQ), and bioactive composite (AC) were divided into 3 subgroups: 0, 35, and 70 Gy fractional radiation doses. The specimens were subjected to surface roughness, Vickers microhardness, and compressive strength tests. The chemical components and morphology of the tested specimens were observed via energy dispersive spectroscopy and scanning electron microscopy. The data were analyzed using two-way ANOVA with Bonferroni post hoc analysis. After exposure to fractional radiation, the surface roughness increased in all the groups. F9 had the highest surface roughness, while AC had the lowest surface roughness within the same radiation dose. The Vickers microhardness decreased in F9 and EQ. The AC had the highest compressive strength among all the groups, followed by F2. More cracks and voids were inspected, and no substantial differences in the chemical components were observed. After fractional radiation, the surface roughness of all fluoride-releasing materials increased, while the Vickers microhardness of F9 and EQ decreased. However, the compressive strength increased only in F2 and AC.

Evaluating Glass Ionomer Cement Longevity in the Primary and Permanent Teeth-An Umbrella Review.

The aim of this umbrella review was to evaluate the longevity of glass ionomer cement (GIC) as a restorative material for primary and permanent teeth. Research in the literature was conducted in three databases (MedLine/PubMed, Web of Science, and Scopus). The inclusion criteria were: (1) to be a systematic review of clinical trials that (2) evaluated the clinical longevity of GICs as a restorative material in primary and/or permanent teeth; the exclusion criteria were: (1) not being a systematic review of clinical trials; (2) not evaluating longevity/clinical performance of GICs as a restorative material; and (3) studies of dental restorative materials in teeth with enamel alterations, root caries, and non-carious cervical lesions. Twenty-four eligible articles were identified, and 13 were included. The follow-up periods ranged from 6 months to 6 years. Different types of GICs were evaluated in the included studies: resin-modified glass ionomer cement (RMGIC), compomers, and low- and high-viscosity glass ionomer cement. Some studies compared amalgam and composite resins to GICs regarding longevity/clinical performance. Analyzing the AMSTAR-2 results, none of the articles had positive criteria in all the evaluated requisites, and none of the articles had an a priori design. The criteria considered for the analysis of the risk of bias of the included studies were evaluated through the ROBIS tool, and the results of this analysis showed that seven studies had a low risk of bias; three studies had positive results in all criteria except for one criterion of unclear risk; and two studies showed a high risk of bias. GRADE tool was used to determine the quality of evidence; for the degree of recommendations, all studies were classified as Class II, meaning there was still conflicting evidence on the clinical performance/longevity of GICs and their recommendations compared to other materials. The level of evidence was classified as Level B, meaning that the data were obtained from less robust meta-analyses and single randomized clinical trials. To the best of our knowledge, this is the first umbrella review approaching GIC in permanent teeth. GICs are a good choice in both dentitions, but primary dentition presents more evidence, especially regarding the atraumatic restorative treatment (ART) technique. Within the limitation of this study, it is still questionable if GIC is a good restorative material in the medium/long term for permanent and primary dentition. Many of the included studies presented a high risk of bias and low quality. The techniques, type of GIC, type of cavity, and operator experience highly influence clinical performance. Thus, clinical decision-making should be based on the dental practitioner's ability, each case analysis, and the patient's wishes. More evidence is needed to determine which is the best material for definitive restorations in permanent and primary dentition.