Glass Ionomer Restorative Materials Research Articles

Comparative evaluation of long-term fluoride release and antibacterial activity of an alkasite, nanoionomer, and glass ionomer restorative material - An in vitro study.

Background:The antibacterial activity of restorative material and the amount of fluoride released are interlinked. Hence, these are the two foremost properties to be studied.Aim:This study aimed to evaluate and compare the amount and pattern of fluoride release from Type IX GIC (GC HS posterior), nanoionomer (Ketac N100), and alkasite (Cention N), and the antibacterial activity against Streptococcus mutans at 24 and 48 h.Settings and Design:This in vitro study was carried out in laboratory settings with six samples of each group for fluoride release using an ion-chromatography (IC) machine and five samples of each group for antibacterial activity using agar plates.Materials and Methodology:Samples of each group, Group I – Type IX GIC, Group II – nanoionomer, and Group III –alkasite, were prepared, immersed in 2 ml of artificial saliva, and fluoride release recorded using IC after 1, 7, 14, and 28 days intervals. The antibacterial activity against S. mutans was evaluated by placing samples of each group in the agar plates and measuring the diameter of zones of inhibition after 24 and 48 h.Statistical Analysis:One-way ANOVA test to check to mean differences between the groups and Tukey's honestly significant difference post hoc test for multiple intergroup comparisons (P = 0.05).Results:The Type IX GIC showed the highest fluoride release after day1. However, nanoionomer showed the maximum fluoride release for the remaining days. The least amount of fluoride released was from the alkasite throughout the study. The antibacterial activity of nanoionomer was the highest, followed by Type IX GIC and alkasite at both 24 and 48 h.Conclusions:Nanoionomer showed the highest fluoride release and antibacterial activity.

Effect of a wear-resistant resin coat on the color stability of a resin-modified glass ionomer restorative material.

The purpose of this in vitro study was to evaluate the effect of the Equia Forte Coat on the color stability of Equia Forte Fil. Sixty discs of Equia Forte Fil were randomly divided into two groups. One group of 30 samples was treated with Equia Forte Coat according to the manufacturer's directions. The other 30 discs were not coated. All discs were continuously soaked in cola for 7 consecutive days. The color changes in the Equia Forte Fil samples were determined using a colorimeter. The color difference (△E) was calculated using the Commission Internationale de l'Eclairage L*a*b* coordinates. There was a significant difference in ΔE between the two groups (P < 0.0001). The group with Equia Forte Coat had significantly less color change than the group without the Equia Forte Coat. The application of the Equia Forte Coat significantly improved the color stability of Equia Forte Fil.

Comparative Evaluation of Retention and Antibacterial Efficacy of Compomer and Glass Hybrid Bulk Fill Restorative Material as a Conservative Adhesive Restoration in Children with Mixed Dentition-An In Vivo Two-arm Parallel-group Double-blinded Randomized Controlled Study.

Aim and objectiveTo compare and evaluate the retention along with antibacterial efficacy of colored compomer and glass hybrid bulk fill glass ionomer restorative material as a conservative adhesive restoration in children of age 6–12 years.Materials and methodsSixty children were selected fulfilling the inclusion and exclusion criteria falling in the age group of 6–12 years with mixed dentition and two groups were formed: group I—colored compomer and group II—glass hybrid bulk fill material. Initially, oral prophylaxis was carried out and baseline collection of saliva was completed. Then, the restorative treatment was completed. Retention of the material and antibacterial count [colony-forming units (CFU)/mL of saliva] was estimated at 1, 3, and 6 months after the restorative procedure.ResultsIt was seen that retention rate with glass hybrid bulk fill group was 100%, whereas with colored compomer group it was 90% at end of 6 months. Although good antibacterial activity was shown by both the group at 1, 3, and 6 months follow-up but statistically significant drop was seen in the glass hybrid bulk fill group at 3-month intervals than the colored compomer group with a p value of 0.0001 (p < 0.05).ConclusionAmong both the materials, glass hybrid bulk fill restorative material showed good retention compared to Colored compomer material but it was not statistically very significant. Also, both the materials have shown good antimicrobial activity at 1, 3, and 6 months follow-up.How to cite this articleMundada MV, Hugar SM, Hallikerimath S, et al. Comparative Evaluation of Retention and Antibacterial Efficacy of Compomer and Glass Hybrid Bulk Fill Restorative Material as a Conservative Adhesive Restoration in Children with Mixed Dentition—An In Vivo Two-arm Parallel-group Double-blinded Randomized Controlled Study. Int J Clin Pediatr Dent 2020;13(S-1):S45–S54.

Color and translucency stability of contemporary resin-based restorative materials.

To determine color and translucency stability of present-day resin-based restorative materials. Disk-shaped (1.0 × 10 mm) resin composites (Filtek Universal, 3M ESPE; Spectra ST, Dentsply Sirona; Gradia Direct X, GC America; Estilite Quick, Tokuyama; Harmonize, Kerr; ACTIVA Bioactive-Restorative, Pulpdent) were prepared and divided into four staining groups (n=5); coffee (55°C), grape juice (5°C), deionized water (25°C) and thermocycling (20 000 cycles, 5°C to 55°C with a 30-second dwell time). Spectrophotometer measurements were taken at baseline and 14 days for each group and the color stability (CIEDE2000) and changes in the translucency parameter (RTPCIEDE2000 ) and luminous transmittance of each composite were determined. A 2-way analysis of variance (ANOVA) using maximum likelihood estimations was used for analysis for these changes, with subsequent pairwise comparisons using Bonferroni-corrected Student's t tests and an experiment-wise α=0.05. A significant interaction (P < .0001) between material and treatment was found for each change in the esthetic property tested over 14 days. Multiple significant differences between materials for each treatment and between treatments for each material were identified. The severity of color change and translucency of resin-based materials are dependent on their type, mostly affected by the coffee staining medium. Nano-filled resin composite is most resistant to color change and with stable translucency after artificial aging. Nano-filled resin composite may be the most esthetically durable resin- based restorative material. Micro-hybrid resin composite and resin-modified glass ionomer restorative material are susceptible to color change and losing their translucency. Hot coffee solution may shorten the esthetic lifespan of a resin-based material.

Differential induction of surface chemical compositional change on tooth structure by glass ionomer restorative materials.

Glass ionomer cement (GIC) is a restorative dental material capable of promoting mineral deposition on surrounding tooth substrates. However, it is unclear as to whether demineralization and remineralization due to an oral pH change of the tooth affect the dissolution pattern of tooth crown and root differently. It also remains to be elucidated how GIC alters superficial chemical compositions of tooth crown structurally known as enamel, in relation to the root. In this study, we investigated an effect of pH challenge on chemical compositional change of tooth crown and root, as well as the contribution of GIC restorations on a shift of elemental abundance on tooth crown and root. Our findings demonstrated that an exposure to a pH cycling resulted in a drastic change of elemental profile of the root, but not the crown. Modification of superficial elemental ingredients of GIC-restored cavities located on different anatomical part of the tooth was found after an acid attack. Notably, a differential induction of chemical compositional shift was dependent on the type of GIC used and the location of restored GIC. Our study highlights a susceptibility of root portion to acid-induced elemental dissolution, and that GIC use might be implicated in the delayed dissolution rate of the tooth structure.

Impact of a New Silicate-Based Capping Material on Healing Potentiality of Traumatically Exposed Healthy Dog's Dental Pulp

The aim of the current study was to evaluate the impact of a new silicate-based capping material on healing potential of traumatically exposed healthy dog's dental pulp. Materials and Methods: Two pulp capping materials were evaluated in this study; Mineral trioxide aggregate (MTA), and Five mineral oxides (5MO). Glass ionomer as overlying restorative material. Six adult healthy dogs with intact permanent dentition were selected for the study. A total of sixteen anterior teeth were used in each dog. Both pulp capping materials were used in the same dog. Class V cavities were prepared on the teeth. After pulp exposure, the pulp capping materials were applied directly to the exposed pulp. All cavities were sealed with glass ionomer restorative material. The used six dogs were divided into two groups; three dogs each, according to the capping periods to 7 days and 90 days. At the end of each period the dogs were sacrificed by injecting an overdose of pentobarbital sodium. Teeth were separated from bone with immediate sectioning of their roots in the mid-way between cementoenamel junction and apex. The teeth were fixed in 10% neutral buffered formalin. Then the teeth were demineralized in Morse's solution (50% formic acid and 20% sodium citrate) for 3 months. In the last, the teeth were embedded in paraffin wax and serially sectioned buccolingually and stained with hematoxylin-eosin. The specimens were examined under optical light microscope to estimate the amount of pulp inflammation and dentin bridge formation at the interface of the capping materia

Comparative Evaluation of Efficacy of Four Different Materials in the Repair of Amalgam Restorations: An In Vitro Study

This study was aimed to compare the microleakage of amalgam restorations repaired with bonded amalgam, composite resin, ormocer, and glass ionomer restorative material. Sixty extracted maxillary human premolars were prepared and restored with class I amalgam. A simulated defect was prepared that included the cavosurface margin on restorations, and the premolars were assigned to four treatment groups (n = 15): In group I, premolars were treated by bonded amalgam; in group II, premolars were repaired with composite resin; in group III, premolars were repaired by ormocer; and in group IV, premolars were repaired with glass ionomer restorative material. The teeth were immersed in 50% silver nitrate solution, thermocycled, sectioned longitudinally, and then blindly observed under a stereomicroscope by three trained examiners. Microleakage was evaluated using a 0-4 scale for dye penetration, and data were analyzed by Kruskal-Wallis test and Mann-Whitney U-test. The microleakage values were more in the group repaired with glass ionomer restorative material and the Chi-squared test showed no significant difference in between the groups repaired with bonded amalgam, composite resin, and ormocer, but showed significant difference between the groups repaired with ormocer and glass ionomer restorative materials and between composite resin and glass ionomer restorative materials. None of the restorative techniques evaluated were able to completely eliminate marginal microleakage. The results seem to be favorable within the limits of the in vitro conditions of the present study; however, the in vivo conditions are the best for clinically relevant findings.

Clinical evaluation of bulk-fill resins and glass ionomer restorative materials: A 1-year follow-up randomized clinical trial in children.

This prospective study aimed to evaluate the clinical performance of different restorative materials in primary molars with class II carious lesions. A total of 160 class II carious lesions (with radiographic involvement of the outer half of dentin) in 30 patients were randomly divided into four groups and restored with a glass ionomer restorative system (Equia™), two different bulk-fill composites (Sonicfill™ and X-tra fil™), and a nanohybrid composite (Filtek Z550™). The restorations were clinically and radiographically evaluated at the baseline, and 3, 6, and 12 months according to the modified United States Public Health Service criteria. Statistical analyses were performed using Pearson's Chi-square and McNemar tests. After 1 year, 134 restorations were evaluated in 26 patients. Equia was statistically less successful than the other restorative materials in marginal adaptation and retention criteria (P < 0.05). However, no material was found to be superior to the others over the study period in marginal discoloration, color matching, secondary caries, anatomical form, and postoperative sensitivity (P > 0.05). The bulk-fill and conventional composites exhibited good clinical performance, and Equia exhibited minor changes over the 1-year trial period.

Clinical evaluation of glass ionomer with glass hybrid technology versus conventional high viscosity glass ionomer in class I cavities in patients with high caries risk: Randomized controlled trial

Aim: Glass ionomer is a well-known name in caries management and control. Meanwhile, the dark side in its history is being limited as an interim restoration inside patient mouth. The recently introduced glass ionomer with glass hybrid technology could be a new breakthrough in its future. The aim of this study was to evaluate the clinical performance of glass hybrid glass ionomer compared to conventional high-viscosity glass ionomer in class I cavities in patients with high caries risk. Materials and Methods: In a split-mouth design, 31 high caries risk patients with class I cavities received randomly two pairs of restorations, either EQUIA Forte (glass ionomer with glass hybrid technology) or EQUIA Fil (conventional high-viscosity glass ionomer); both materials were applied according to manufacturer’s instructions. Restorations were evaluated at baseline (1 week) and after 1 year by two blinded assessors using Federation Dentaire Internationale criteria for assessment of dental restoration measuring (functional properties and biological properties). Results: Chi-square test was used to compare the difference between glass-ionomer restorative materials at the base line and after 1 year. A value of P ≤ 0.05 was considered statistically significant. There was no statistically significant difference between both materials for all tested outcomes with 100% success rate (score 1 or 2). Conclusion: Glass hybrid glass-ionomer restoration has shown clinical performance similar to conventional high-viscosity glass-ionomer restoration in class I cavities in patients with high caries risk after 1 year of clinical service.

Effect of different polishing techniques on surface roughness and bacterial adhesion of three glass ionomer-based restorative materials: In vitro study.

BackgroundAlthough many reports concluded that polishing of glass ionomers is crucial for smoother surface and limiting the adhesion of cariogenic bacteria, there is no specific surface treatment protocol recommended. A novel material in the same category was released recently claimed to have surface smoothness comparable to resin composite and bacterial adhesion less than other types of glass ionomers. In this study, different polishing systems were tested with three glass ionomers one of them is the novel material to find the most appropriate polishing protocol. Objectives: To evaluate and compare the surface roughness and bacterial adhesion to resin modified glass ionomer, bioactive ionic resin and conventional glass ionomer restorative materials after different polishing protocols in vitro. Material and MethodsThe materials tested includes resin modified glass ionomer, bioactive ionic resin, and conventional glass ionomer. The polishing protocols were divided into four groups: group 1 = (Mylar matrix strips, Control), group 2 = (one-step, PoGo), group 3 = (two-step, Prisma Gloss) and group 4 = (three-step, Sof-Lex). From each material, eleven cylindrical specimens were prepared for each group according to the manufacturers’ instructions. The surface roughness for all specimens was measured using atomic force microscope in tapping mode. the same specimens were subjected to bacterial adhesion testing after being coated with artificial saliva. Data were analyzed with two-way analysis of variance followed by Post hoc multiple comparisons. ResultsThe highest Ra and S. mutans adhesion values were recorded for all materials in two-step group. The lowest Ra and S. mutans adhesion values were seen in one-step and three step groups. ConclusionsOne-step polishing system was more effective and may be preferable for polishing of the three studied glass ionomer-based materials compared to two-step and three-step systems. Key words:Activa bioactive restorative, glass ionomer, surface roughness, bacterial adhesion, surface treatment.

Properties of New Glass-Ionomer Restorative Systems Marketed for Stress-Bearing Areas.

The purpose of this study was to evaluate the properties (fracture toughness, surface hardness) of newer conventional glass-ionomer restorative materials that are marketed for posterior stress-bearing areas compared with more traditional glass-ionomer restorative materials marketed for non-load-bearing areas and composite-resin restorative materials. Notched-beam fracture toughness specimens were created in a mold with each tested material (Equia Forte, GC America, with and without a surface coating of Equia Forte Coat; Ketac Universal, 3M/ESPE; ChemFil Rock, Dentsply; Fuji IX GP Extra, GC; Ionostar Molar, VOCO; Filtek Z250, 3M/ESPE; Filtek Supreme Ultra, 3M/ESPE) and fractured using a universal testing machine after 24 hours of storage. Hardness values were determined on the surface of the fracture toughness specimens using a hardness tester. Data were analyzed with a one-way ANOVA and Tukey's post hoc test per property (alpha=0.05). The composite-resin restorative materials had significantly greater fracture toughness than the glass-ionomer materials. There was no significant difference in fracture toughness between the glass-ionomer materials. The use of a resin coating significantly increased the surface hardness of the newer glass ionomer marketed for stress-bearing areas. Fracture toughness was not improved with the newer glass-ionomer restorative materials marketed for stress-bearing areas compared to the conventional glass-ionomer materials, however a resin coating provided greater surface hardness.

A randomized controlled 10 years follow up of a glass ionomer restorative material in class I and class II cavities

ObjectiveTo evaluate the durability of a glass ionomer restorative material in Class I and Class II cavities during 10 years compared with a micro filled composite resin. MethodsFifty-nine participants (mean age 24 years) received 140 (80 Class I and 60 Class II) glass ionomer (GI) or composite resin (CR) restorations. Evaluation was performed with slightly modified USPHS criteria at baseline, and yearly during the 10 years. Data were analyzed with Cohran's Q and McNemar's tests. ResultsFifty-one patients and 124 restorations (61 GI / 38 Class I - 23 Class II, 63 CR / 38 Class I, 25 Class II) were evaluated after 10 years. The recall rate was 86.4%. The overall clinical recall rate of restorations was 88.6%. The success rate of Class I and II restorations were calculated as 100% for both materials. The cumulative failure rate (CRF) of all Cl I and Cl II GI restorations was 3.17% in total, but CFR was 8 % for Cl II GI restorations. A significant difference was observed between the marginal discoloration scores of restorations at 10 years (p = 0.022). No significant difference was seen between two restorative materials in terms of marginal adaptation (p > 0.05). A significant change was seen in color match of GI restorations at 10 years (p < 0.05). No significant change was found for the anatomical form, secondary caries, postoperative sensitivity, surface texture, and retention for either restorative material (p > 0.05). ConclusionsBoth tested restorative materials showed an acceptable success rate in the restoration of Class I and Class II cavities during the 10-year follow up.

Healing Capacity of Autologous Bone Marrow–derived Mesenchymal Stem Cells on Partially Pulpotomized Dogs' Teeth

IntroductionPartial pulpotomy is a vital treatment for carious and traumatic exposure, especially in young permanent teeth. Cell-based therapy for partially pulpotomized teeth can be considered a promising approach for dentin-pulp complex regeneration. This study evaluated the healing capacity of autologous bone marrow–derived stem cells (BMSCs) on partially pulpotomized teeth in a dog model. MethodsTwelve mongrel dogs were selected, and a total number of 192 posterior mandibular and maxillary teeth were involved in the study (16 teeth per dog). Partial pulpotomies were performed, and the dogs were assigned into 2 equal groups (groups 1 and 2), 6 dogs in each group. The coronal pulp cavities (n = 96) of group 1 were filled with calcium silicate–based capping material. Group 2 coronal pulp cavities (n = 96) were seeded with 1 × 105 cell/mL BMSCs, and then the cavities were filled with calcium silicate–based capping material. After placing the capping materials, the cavities of both groups (1 and 2) were filled with resin-modified glass ionomer restorative material. From each group, 48 teeth from 3 dogs were evaluated histologically after 1 week, and the other 48 teeth from the remaining 3 dogs were evaluated after 9 weeks. Scoring was done for the amount of inflammatory cell infiltrates, tissue necrosis, and thickness of hard tissue bridge formation. ResultsThe Mann-Whitney U statistical test performed for hard tissue bridge formation revealed significant differences between the 2 groups at the 1- (P < .05) and 9-week (P < .05) examination periods. ConclusionsAutologous BMSCs have significant therapeutic potential because they enhance the healing capacity of partially pulpotomized dogs' teeth.

Influence of external energy sources on the dynamic setting process of glass-ionomer cements

ObjectiveTo evaluate the influence of external energy sources on the dynamic setting process of glass-ionomer restorative materials. MethodsEighteen brands of GIC were studied: Bioglass R (Biodinâmica; G1), Chemfil Rock (Dentsply; G2), Equia Forte (GC; G3), Gold Label 2 (GC; G4), Gold Label 9 (GC; G5), Glass Ionomer Cement Type II — (Shofu; G6), Ionglass R (Maquira; G7), Ion Z (FGM; G8), Ionomaster (Wilcos; G9), Ionofil Plus (Voco; G10), Ionostar Plus (Voco; G11), Ketac Molar easymix (3M ESPE; G12), Magic Glass R (Vigodent; G13), Maxxion R (FGM; G14), Riva Self Cure (SDI; G15), Vidrion R (SS White; G16), Vitro Fil R (Nova DFL; G17) and Vitro Molar (Nova DFL; G18). LED, halogen light or ultrasound (n=20 for each set) applied for 30s was used to activate setting, and a control group of each material was allowed to set without activation. Samples were analyzed by FTIR spectroscopy using the ratio of intensities of bands at 1637cm−1 (carboxylate) and 1720cm−1 (carbonyl) as a function of time. Means and standard deviations were subjected to ANOVA and Tukey tests (p<0.05). ResultsAll three activation modes significantly reduced the time at which the carboxylate content became stable in G2, G4, G5, G6, G8, G10, G14, G16, G17 and G18. By contrast, in G1, G7, G12 and G15 no activation source had any significant effect (p>0.05). SignificanceExternal activation sources, namely LED, halogen light and ultrasound, typically but not always increase the setting rate of restorative GICs.

In vitro investigation of antimicrobial effects, nanohardness, and cytotoxicity of different glass ionomer restorative materials in dentistry.

The aim of this in vitro study was to investigate the antimicrobial effects, nanohardness, and cytotoxicity of different glass-ionomer restorative materials in dentistry. The following glass-ionomer restorative materials were used in our study: Argion (VOCO, Germany), Zirconomer (Shofu Inc., Japan), EQUIA Forte (GC, Japan), Fuji II LC capsule (GC, Japan), and Fuji IX GP capsule (GC, Japan). For the cytotoxicity test, a cell culture without release liquids was used as the control group. Microdilution and a disk diffusion test were used to measure the antimicrobial activity. The MTT (3- [4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide) assay was used to evaluate cytotoxicity. Nanohardness was measured using a nanoindenter device. Our study determined that all restorative materials used in this study inhibited bacterial growth in cultures containing 1 × 102 cfu/ml of the bacterial concentrations (Lactobacillus casei and Streptococcus mutans) and that all restorative materials inhibited fungal growth in the cultures containing <1 × 102 cfu/ml of the fungal strains (Candida albicans). IC50 values obtained for the cytotoxicity test were analyzed using the Chi-square test. After a 72-h incubation period, Zirconomer, EQUIA Forte, Fuji IX GP capsule, and Fuji II LG capsule showed statistically significant lower cell viability values. (P < 0.05). The Kruskal-Wallis analysis was performed on the values obtained from the nanohardness test; the differences between the groups were found to be significant (P < 0.05). All materials tested showed low antimicrobial activity, and the antifungal activity of these materials was found to be lower than their antimicrobial activity. Only Argion showed non-cytotoxic effect. Beginning with the group with the highest nanohardness values and ending with the lowest, the groups are ranked in the following order: Fuji II LC capsule, EQUIA Forte, Argion, Fuji IX GP capsule, and Zirconomer.

Effect of mouthwashes on the integrity of composite resin and resin modified glass ionomer: In vitro study.

BackgroundThe constant search for an improved esthetic dental material has led investigators to realize that its performance depends on the conditions where the material is used. It has been probed that the contact with mouth rinses triggers alterations, reason why the aim of this study was to identify their possible effects of it on the integrity of nanohybrid composite resin and resin modified glass ionomer.Material and MethodsA total of 144 samples were manufactured with two nanohybrid composite resins and two resin modified glass ionomer restorative materials. The specimens were immersed in one of the three mouthwashes used in the study, for a total of 1092 minutes, with intervals of contact with artificial saliva. This strategy simulates three years of constant use of mouthwashes. The samples weight and surface roughness measurement was recorded with a precision scale and profilometer, at different stages: At the beginning of the study, after 546 minutes (simulating one and a half year), and after 1092 minutes (simulating three years).ResultsThe collected data on surface roughness and weight were submitted to the analysis of variance (ANOVA), with repeated measures of three factors. The results determined shifts in values in terms of weight and roughness in all the samples. The composite resin “Grandio” group was the one that showed bigger shifts, while the glass ionomer group “Vitremer” showed stability on its structure. The evaluated mouthwashes displayed similar behavior between each other.ConclusionsThe use of mouthwashes triggered changes on the structure of both dental materials: composite resin and resin modified glass ionomer mostly associated with surface roughness. Key words:Glass ionomer, composite resin, mouthwash, roughness, degradation.

In Vitro Analysis of Techniques that Alter the Surface Hardness of a Glass Ionomer Restorative Material

The aim of this in vitro study was to compare the effect of different manipulation techniques on the surface hardness of ChemFil Rock glass ionomer. The changes in Vickers surface hardness (VH) of ChemFil Rock were evaluated after the application of five manipulation techniques and compared with one control group (n = 60). The manipulation techniques included: finger pressure set, electronic piezo producing a high frequency set, air piezo producing a low frequency set, heat-set achieved with a curing light and the last technique was a combination of electronic piezo followed by heat-set. Standard set was the control. The average surface hardness for the standard set was 49.5 VH. No statistical differences were demonstrated when the means were compared for finger pressure set (49.2 VH) or the air piezo set (48.49 VH) with standard set. The electronic piezo (54.21 VH) and the heat-set (57.5 VH) had an increased mean surface hardness when compared to other techniques. Heat-set had the highest surface hardness demonstrating a significant statistical difference when compared with standard set, finger pressure set, air piezo set as well as the combination of electronic piezo (p < 0.05). The surface hardness of the glass ionomer cement (GIC) material assessed in this study can be predictably improved by applying the heat-set technique. A command set can be achieved with the electronic piezo or the air piezo, however, the surface hardness will only increase with the use of the electronic piezo. The clinical advantage of using the air piezo as well as the electronic piezo technique would lie in preventing moisture contamination and dissolution of the GIC due to the command set effect of the ultrasonic vibrations within 15 seconds. The heat technique with the LED curing light will reduce the setting time to 90 seconds.

Variation in the Dispersions of Powder Liquid Ratios in Hand-Mix Glass Ionomers.

Background:The Powder/Liquid Ratio (PLR) influence, and the literature regarding the handling and physical properties of Glass Ionomer restorative materials (GIC) were investigated.Objective:The objective of the study was to compare the PLR variability and magnitude in hand-mix GICs, as dispensed for clinical use. From the recorded individual powder and liquid weights, additional comparisons could be made by pairing the various “extreme” outer observations in relation to the manufacturer’s PLR.Study Design:The materials assessed were Ketac Universal Hand-mix (KUH), Riva Self Cure Hand-mix (RSCH) and Fuji IX GP Hand-mix (FIXH). Twenty scoops of powder were paired with twenty drops of liquid, as would be the case in the clinical scenario. Statistical analysis was completed with the Kruskal Wallis H test, Intraclass Correlation (ICC) and straight line regressions with One-way ANOVA and the post-hoc Tukey HSD Test (p<0.05 was considered significant).Results:The powder and liquid observations indicate a lack of consistency in both the powder and liquid dispersions. The volume remained “one drop” but the weights were much lower than the manufacturer’s recommended drop weight for some observations, due to air in the liquid drop. The Kruskal-Wallis H test indicated significant differences (p=0.0001) between the three materials for the paired PLRs. The One-way ANOVA and post-hoc Tukey HSD Test were used to compare the recommended PLR to the results and the significant differences (p<0.01).Conclusion:The recommended manufacturers’ powder and liquid weights were KUH 0.150/0.05g; RSC 0.165/0.035; FIXH 0.18/0.05, respectively. KUH, FIXH and RSCH liquid had powder and liquid dispersions above the manufacturer’s recommendations. FIXH had the most paired PLR observations within the ±10% range followed by KUH. Extreme powder and liquid combinations could occur in the clinical scenario and these combinations were considered.

Evaluating the Mechanical Properties, and Calcium and Fluoride Release of Glass-Ionomer Cement Modified with Chicken Eggshell Powder.

The aim of this study was to test the effect of adding chicken eggshell powder (CESP) to conventional glass-ionomer cement (GIC) on its mechanical properties, and fluoride and calcium release. CESP was added with proportions of 3% and 5% by weight to the powder component of conventional glass-ionomer cement. The specimens were categorized into group A: GIC without CESP; group B: GIC with 3% wt. CESP; and group C: GIC with 5% wt. CESP; there were 12 specimens in each group. Groups B and C showed higher compressive strength values compared to group A. However, microhardness scores were higher in group C compared to groups A and B. As for ion-release results, group B displayed the highest values of fluoride release followed by group C at both 7 and 30 days. Group C showed the highest amount of calcium release followed by both groups B and C at 7 days, while at 30 days, groups A and B showed higher calcium release compared to group C. The mechanical properties of conventional glass-ionomer restorative material were enhanced by the addition of CESP. Moreover, fluoride and calcium release were not compromised by adding CESP.

Physical property investigation of contemporary glass ionomer and resin-modified glass ionomer restorative materials.

The objective of this study was to investigate selected physical properties of nine contemporary and recently marketed glass ionomer cement (GIC) and four resin-modified glass ionomer cement (RMGI) dental restorative materials. Specimens (n = 12) were fabricated for fracture toughness and flexure strength using standardized, stainless steel molds. Testing was completed on a universal testing machine until failure. Knoop hardness was obtained using failed fracture toughness specimens on a microhardness tester, while both flexural modulus and flexural toughness was obtained by analysis of the flexure strength results data. Testing was completed at 1h, 24h, 1week, and then at 1, 3, 6, and 12months. Mean data was analyzed with Kruskal-Wallis and Mann-Whitney (p = 0.05). Physical properties results were material dependent. Physical properties of the GIC and RMGI products were inferior at 1h compared to that at 24h. Some improvement in selected physical properties were noted over time, but development processes were basically concluded by 24h. A few materials demonstrated improved physical properties over the course of the evaluation. Under the conditions of this study: 1. GIC and RMGI physical property performance over time was material dependent; 2. Polyalkenoate maturation processes are essentially complete by 24h; 3. Although differences in GIC physical properties were noted, the small magnitude of the divergences may render such to be unlikely of clinical significance; 4. Modest increases in some GIC physical properties were noted especially flexural modulus and hardness, which lends support to reports of a maturing hydrogel matrix; 5. Overall, GIC product physical properties were more stable than RMGI; 6. A similar modulus reduction at 6months for both RMGI and GIC produced may suggest a polyalkenoate matrix change; and 7. Globally, RMGI products demonstrated higher values of flexure strength, flexural toughness, and fracture toughness than GIC materials. As compared to RMGI materials, conventional glass ionomer restorative materials demonstrate more stability in physical properties.