Compressive Strength Of Glass Ionomer Cement Research Articles

COMPARATIVE EVALUATION OF COMPRESSIVE STRENGTH OF CENTION N AND TYPE IX GLASS IONOMER CEMENT – AN INVITRO STUDY

BACKGROUND: This study aimed to compare the compressive strength of glass-ionomer cement (GIC) Type IX and Cention N. METHODS: Five samples each of GIC Type IX and Cention N were prepared for testing the compressive strength. Cylinders of the samples measuring 1 cm diameter and 6 mm height were prepared for compressive strength. Testing was done by mounting the samples in a universal testing machine with a crosshead speed of 1 mm/min. RESULTS: The mean compressive strength of Type IX GIC (n=10) was 94.010 with standard deviation ±15.654 while the mean compressive strength of Cention V (n=10) was 125.567 with standard deviation ± 7.890. The values of the compressive strength Cention N were statistically significant (P < 0.5) as compared to GIC Type IX. CONCLUSION: The results suggest significantly higher values for mechanical properties of Cention N as compared to GIC Type IX.

Antimicrobial activity of biosynthesized silver nanoparticles, amoxicillin, and glass-ionomer cement against Streptococcus mutans and Staphylococcus aureus

Background. The development of dental caries is associated with various microorganisms and secondary caries formation is the main cause of restorations failure. The advice for restorative dental materials that have antimicrobial properties has stimulated the introduction of materials containing different antibacterial agents. Objectives. The present study has been designed to synthesize silver nanoparticles (AgNPs) and incorporate AgNPs and amoxicillin into glass ionomer cement (GIC) to synergize its effect on oral microbes. The effect of the added antimicrobial agents on compressive strength (CS) of GIC was also evaluated. Material and methods. Biosynthesis of AgNPs was done using Cupressus macrocarpa extract and AgNPs were characterized. A total of 120 disc-shaped specimens were prepared and classified into 4 main groups where Group A includes conventional GIC, Groups B and C include GIC with AgNPs or amoxicillin, respectively, while Group D included GIC with both AgNPs and amoxicillin. Each group was tested for the antimicrobial activity against both Streptococcus mutans (S. mutans) and Staphylococcus aureus (S. aureus). The distribution of biofilm was examined via a scanning electron microscope. The CS of the tested material was measured using a Material Test System. Results. The UV−visible spectrum showed a peak of 429 nm. Transmission electron microscopy, x-ray diffraction pattern and Fourier transform infrared analysis confirmed the formation of AgNPs with spherical to oblong polydispersed particles of diameter in the range of 13.5–25.8 nm. The maximum inhibitory zone was recorded for group D against both tested bacteria with a mean of 29 mm at first 24 h period to 15 mm at three weeks and showed antimicrobial rate 92.2% and 92.56%, against both strains, respectively. Additionally, group D disintegrated the structure of S. aureus biofilm and even kill bacteria in the biofilms. The addition of AgNPs and amoxicillin caused an insignificant effect on CS of GIC. Conclusion. TheAgNPs showed a synergistic effect in combination with amoxicillin and GIC dental restorative material against studied microorganisms. The agents can be safely added with minimal effect on the mechanical properties of the original cement.

The effect of powder to liquid ratio on physical properties and fluoride release of glass ionomer cements containing pre-reacted spherical glass fillers.

The aim was to assess the effect of powder to liquid ratio (PLR) on setting time, fluoride release, and compressive strength of conventional glass ionomer cements (GICs) containing pre-reacted spherical glass fillers (SPG). GICs were prepared by mixing SPG with Fuji IX Universal liquid using PLR of 1:1, 1.5:1, 2:1, 2.5:1, 3:1. Setting time decreased from 221 to 51 s upon rising PLR. Increasing PLR decreased cumulative fluoride release (33 to 13 ppm). Diffusion coefficient of fluoride of experimental GICs (1.6-1.8×10-8 cm2/s) was comparable with that of Fuji IX Universal (1.6×10-8 cm2/s). Compressive strength of PLR 2:1 to 3:1 (93-140 MPa) were comparable with that of Fuji IX Universal (124 MPa). These results demonstrated that rising powder ratio reduced setting time, fluoride release, and compressive strength of GICs. However, the setting time and strength experimental GICs with PLR greater than 2:1 were in the acceptable range of the ISO standard.

Modified Glass Ionomer Cement with "Remove on Demand" Properties: An In Vitro Study.

Objectives: To investigate the influence of different temperatures on the compressive strength of glass ionomer cement (GIC) modified by the addition of silica-coated wax capsules; Material and Methods: Commercially-available GIC was modified by adding 10% silica-coated wax capsules. Test blocks were fabricated from pure cement (control) and modified cement (test), and stored in distilled water (37 °C/23 h). The compressive strength was determined using a universal testing machine under different temperatures (37 °C, 50 °C, and 60 °C). The maximum load to failure was recorded for each group. Fractured surfaces of selected test blocks were observed by scanning electron microscopy (SEM); Results: For the control group, the average compressive strength was 96.8 ± 11.8, 94.3 ± 5.7 and 72.5 ± 5.7 MPa for the temperatures 37 °C, 50 °C and 60 °C respectively. The test group reported compressive strength of 64.8 ± 5.4, 47.1 ± 5.4 and 33.4 ± 3.6 MPa at 37 °C, 50 °C and 60 °C, respectively. This represented a decrease of 28% in compressive strength with the increase in temperature from 37 °C to 50 °C and 45% from the 37 °C to the 60 °C group; Conclusion: GIC modified with 10% silica-coated wax capsules and temperature application show a distinct effect on the compressive strength of GIC. Considerable compressive strength reduction was detected if the temperature was above the melting temperature of the wax core.

Saliva buatan meningkatkan kekuatan tekan semen ionomer kaca tipe II yang direndam dalam minuman isotonik (Artificial saliva increases the compressive strength of glass ionomer cement type II soaked in isotonic drinks)

Immersion of glass ionomer cement (GIC) type II in acid drink like isotonic drink could reduce its compressive strength.This is due to the matrix degradation process of GIC in acid condition. However, there is artificial saliva that canneutralize this condition. The purpose of this study was to evaluate the effect of artificial saliva on compressive strengthof glass ionomer cement type II immersed in isotonic drink. The GICspecimens of 6 x 6 x 12 mm3beam were immersed for24 hours in distilled water, 24 hours in isotonic drink, 24 hours in isotonic drink continued with 72 hours in artificial saliva,48 hours in isotonic drink, and 48 hours in isotonic drink continued with 144 hours in artificial saliva. The compressivestrength was measured using Universal Testing Machine with a crosshead speed of 0.5 mm/min. Statistical analysis wasperformed by one-way ANOVA and post-hoc LSD test (=0.05) showed a significant difference of compressive strength(p<0,05). It was concluded that artificial saliva increases the compressive strength of GIC immersed in isotonic drink.

The effects of boric acid and phosphoric acid on the compressive strength of glass-ionomer cements

Both boric acid (H3BO3) and phosphoric acid (H3PO4) are components of dental cements, commonly incorporated into glass (as ingredients in the melt) and occasionally added to the powder or liquid components. This study investigated the effect of boric acid addition to an experimental glass-ionomer powder and the effect of phosphoric acid addition to a glass-ionomer liquid on the 24-h compressive strength. Boric acid powder was added in various concentrations to an experimental glass-ionomer powder and, separately, phosphoric acid was added to an experimental glass-ionomer liquid. Powders and liquids were dosed into capsules at various powder:liquid ratios and cements thus formed were assessed for 24-h compressive strength. Incorporation of boric acid in glass-ionomer powder resulted in a pronounced decrease (p < 0.05 at 1% boric acid) in compressive strength. Addition of phosphoric acid produced initially stronger cements (up to 13% increase at 1% phosphoric acid) before also declining. The incorporation of less than 2% w/w phosphoric acid in glass-ionomer liquids may improve cement strengths without compromising clinical usefulness. The incorporation of boric acid in glass-ionomer cements is contraindicated.

The effect of using layered specimens for determination of the compressive strength of glass-ionomer cements.

Compressive strength is widely used as the criterion of strength of glass-ionomer dental cements, despite the difficulties in interpretation of the findings. With the introduction of light-cured glass-ionomer cements, which can be used only in thin layers, the question arises of how test specimens should be prepared for the measurement of compressive strength. A suggested method has been to prepare test pieces by building them up in layers, an approach which is examined critically in the current paper. Two different conventional (acid-base) glass-ionomers were studied with the use of layered and unlayered specimens of dimensions 6 mm (height) x 4 mm (diameter) and 12 mm (height) x 6 mm (diameter). While smaller samples gave the same value of compressive strength as larger specimens, layered specimens gave significantly lower values of compressive strength for both sizes. In view of these findings, and since the layered specimens are tedious to prepare, we conclude that compressive strength is unsatisfactory as a criterion of strength for light-cured glass-ionomer cements.