Activity Of Glass Ionomer Cement Research Articles

Antibacterial Activity of Nano-Sized Gourami Fish Scales Powder (Osphronemus Gourami) Added to Conventional Glass Ionomer Cement

Background: Gourami scales contain antibacterial compounds, e.g., catechins, chitin, calcium, omega 3, omega 6, and flavonoids. Our previous studies have shown that millimicrons-sized gourami fish scales powder (GFSP) added to Glass ionomer cement (GIC) acts as an immunomodulator against Streptococcus mutans both in vitro and in vivo. However, the antibacterial activity of the material was affected by the particle size, and the effects of smaller GFSP, which is nano-sized (nGFSP), on oral biofilms are largely unknown. Materials and Methods: This study analyzed the potential of nGFSP added to conventional GIC in inhibiting the growth of Streptococcus sanguinis, Streptococcus mutans, and Staphylococcus aureus. nGFSP were divided into five groups, 0% (control), 0.5%, 1.5%, 2.5%, and 3.5% (4 samples for each group). The antibacterial activity was evaluated using the agar diffusion method. Then, the diameter of the inhibition zone was measured and analyzed using ANOVA followed by the LSD test. Results: Antibacterial activity against S. sanguinis, S. aureus, and S. mutans significantly increased with nGFSP. The largest zone of inhibition was measured at a concentration of 3.5%, that is, 4.02 mm (S. sanguinis) and 2.29 mm (S. aureus). Meanwhile, nGFSP is more effective in inhibiting the growth of S. mutans in an optimum concentration of 0.5% with a zone of inhibition is 3.54 mm. Conclusion: The addition of nGFSP improved the antibacterial activity of GIC against gram-positive pathogenic bacteria, such as S. sanguinis, S. aureus, and S. mutans.

In-Vitro antibacterial activity of glass ionomer cements containing silver nanoparticles synthesized from leaf extract of Mentha piperita

Purpose: The aim of this study was to evaluate the antibacterial activity of glass ionomer cement incorporated with silver nanoparticles (AgNPs) synthetized using mint leaf extract (Mentha piperita, M. piperita) on some oral cavity bacteria.Materials and methods: In the present study, M. piperita leaf extract was used for the synthesis of AgNPs. A total of 60 glass ionomer cement (GIC) disk-shaped specimens were prepared and divided into two groups: conventional GIC (C-GIC), and glass ionomer cement with 2 wt% AgNPs (GIC-AGNPs). The antibacterial activity of the GIC specimens in comparison with Ampicillin disk (10 µg/ml) was investigated against Streptococcus mutans, Enterococcus faecalis, Lactobacillus acidophilus, Lactobacillus casei, and Streptococcus aureus by measuring the diameter of growth inhibition zones.Results: C-GIC specimens failed to show any antibacterial effect against the studied bacteria. However, the GIC-AgNPs had relatively significant antibacterial effects on S. mutans, L. acidophilus, L. casei and S. aureus. The highest antibacterial effect of GIC-AgNPs specimens was reported against L. acidophilus (P <0.001). GIC-AgNPs had no antibacterial effect on E. faecalis.Conclusion: Glass ionomer cement incorporated with AgNPs synthetized using M. piperita showed a promising antibacterial effect against oral cariogenic pathogens.

Effect of Nanostructures on the Properties of Glass Ionomer Dental Restoratives/Cements: A Comprehensive Narrative Review.

Overall perspective of nanotechnology and reinforcement of dental biomaterials by nanoparticles has been reported in the literature. However, the literature regarding the reinforcement of dental biomaterials after incorporating various nanostructures is sparse. The present review addresses current developments of glass ionomer cements (GICs) after incorporating various metallic, polymeric, inorganic and carbon-based nanostructures. In addition, types, applications, and implications of various nanostructures incorporated in GICs are discussed. Most of the attempts by researchers are based on the laboratory-based studies; hence, it warrants long-term clinical trials to aid the development of suitable materials for the load bearing posterior dentition. Nevertheless, a few meaningful conclusions are drawn from this substantial piece of work; they are as follows: (1) most of the nanostructures are likely to enhance the mechanical strength of GICs; (2) certain nanostructures improve the antibacterial activity of GICs against the cariogenic bacteria; (3) clinical translation of these promising outcomes are completely missing, and (4) the nanostructured modified GICs could perform better than their conventional counterparts in the load bearing posterior dentition.

A Repeated State of Acidification Enhances the Anticariogenic Biofilm Activity of Glass Ionomer Cement Containing Fluoro-Zinc-Silicate Fillers.

This study aimed to evaluate the anticariogenic biofilm activity of a novel zinc-containing glass ionomer cement, Caredyne Restore (CR), using a flow-cell system that reproduces Stephan responses. Streptococcus mutans biofilms were cultured on either CR or hydroxyapatite (HA) discs mounted on a modified Robbins device. The media were allowed to flow at a speed of 2 mL/min for 24 h while exposed to an acidic buffer twice for 30 min to mimic dietary uptake. Acid exposure enhanced biofilm inhibition in the CR group, which showed 2.6 log CFU/mm2 in viable cells and a 2 log copies/mL reduction in total cells compared to the untreated group after 24 h of incubation, suggesting enhanced anticariogenic activity due to the release of fluoride and zinc ions. However, there was no difference in the number of viable and total cells between the two experimental groups after 24 h of incubation in the absence of an acidic environment. The anticariogenic biofilm activity of CR occurs in acidic oral environments, for example in the transient pH drop following dietary uptake. CR restorations are recommended in patients at high risk of caries due to hyposalivation, difficulty brushing, and frequent sugar intake.

Studying the effect of Egyptian propolis on antimicrobial properties of glass ionomer cement

Background: Dental caries is a major concern to the dentist. Many bacterial subspecies are associated with caries, but Streptococcus mutans is still the most important bacterium in the initiation and progress of this disease. the direction toward natural products for medicinal purposes has gained much attention, as these natural products have proven to be effective with less toxic side effects. Studies have also shown other important properties in propolis such as antibacterial, antifungal, antiviral, anti-inflammatory, anesthetic, and ability to promote healing. Objective: To study the effect of propolis ethanolic extract (EEP) on enhancing the antimicrobial activity of glass ionomer cement (GIC). Methods: Two EEP 25% & 50% concentrations were evaluated for antimicrobial activity, in combination with GIC using agar Disk Diffusion test and broth microdilution test. Results: The diameter of the inhibition zone increased with 25% EEP & 50% EEP over the control by 14.4% and 19.6%, respectively. While increasing the concentration from 25% to 50% resulted in only 5% increase in the inhibition zone. MIC calculation for the three groups revealed, the combination of GIC and EEP has reduced the mic against Streptococcus mutans by two folds. Conclusion: The addition of propolis in different concentrations to GIC increased the antibacterial effect. 25% EEP gave the best antibacterial action with the lowest concentration.

Antibacterial efficacy of chlorhexidine, betadine, and probiotic incorporated glass-ionomer cements – An in vitro study

Addition of antibacterial agents to conventional glass-ionomer cement (GIC) eliminates the recurrence of decay around margins of restoration by inhibiting growth of microbial colonies. Objective: The objective of the study was to comparatively evaluate the antibacterial activity of GIC impregnated with betadine, probiotic, and chlorhexidine (CHX) powder against Streptococcus mutans. Materials and Methods: Chlorhexidine, betadine, and probiotic powder were added to GIC powder to achieve 2.5% CHX-GIC, 2.5% betadine-GIC, and 2.5% probiotic-GIC formulation. Fuji-IX GIC was used as a negative control. The powder and liquid were mixed and inserted in to the wells punched in agar plates. The antibacterial activity of cements was assessed at day 1, day 7, and day 15 using agar diffusion method. Results: There was no inhibition zone present on bacterial plates with control GIC. On day 1, mean inhibition zone against S. mutans was highest with probiotic-GIC (11.70±0.48 mm), followed by betadine-GIC (10.70±0.48 mm) and CHX-GIC (2.70±1.9 mm). On day 7, mean inhibition zone with probiotic-GIC was 5.30±0.83 mm, betadine-GIC was 3.50±0.71 mm, and CHX-GIC was 1.8±1.03 mm. No inhibition zone was observed with any group on day 15. Wilcoxon signed-rank test showed a significant difference in the inhibition zones on day 1 and day 7 with probiotic-GIC (p=0.0001) and betadine-GIC (p=0.001). Significant difference was observed between groups using Kruskal–Wallis test and post hoc Bonferroni tests (p<0.05). Conclusion: Probiotic-GIC, betadine GIC is more effective against S. mutans. With its enhanced antimicrobial effect, these cements can be considered as an alternative to the conventional GIC’S.

Comparative evaluation of antimicrobial efficacy of glass ionomer cement added with propolis, chitosan, and chlorhexidine against Streptococcus mutans and Lactobacillus acidophilus: An in vitro study.

Glass ionomer cement (GIC) is known for its antimicrobial activity due to its low pH and fluoride release. The fluoride released has an inhibitory effect on a finite number of bacteria which leads to the risk of recurrent caries. Additives such as chlorhexidine (CHX) and triclosan have been tried to maximize the antibacterial activity of GIC. Although CHX is known for its impressive antimicrobial action, it has adverse after effects which include alteration of commensal oral flora, staining of teeth, etc., Hence, there is a need for a material with improved antimicrobial efficacy with nominal side effects. The aim of this study is to assess the antimicrobial efficacy of conventional GIC added with Propolis, Chitosan (CH), and CHX against Streptococcus mutans and Lactobacillus acidophilus. Eighty discs of size 10 × 2 mm are prepared with Conventional GIC and GIC added with Propolis, CH and CHX (n = 10) and tested against S. mutans and L. acidophilus using the agar diffusion assay. Zones of inhibition are measured for day 1, 7, and 14, and the data were tabulated and analyzed. One-way ANOVA test for intragroup and Tukey's post hoc test for intergroup comparison. The mean value of zone of inhibition (in mm) against S. mutans on day 14 for Group I, II, III, and IV are 11.70 ± 1.49, 16.50 ± 2.23, 19.30 ± 2.87, and 15.60 ± 2.76, respectively. For L. acidophilus, the mean value of the zone of inhibition (in mm) on day 14 are 8.40 ± 0.97, 9.70 ± 0.68, 16.20 ± 2.04, and 12.50 ± 0.97 for Group I, II, III, and IV, respectively. Higher antimicrobial activity was shown by GIC with CHX against both strains. GIC with Propolis and GIC with CH were effective in inhibiting S. mutans and L. acidophilus, respectively.

Antimicrobial Activity of Glass Ionomer Cements with Chlorhexidine and Propolis: An In Vitro Study

AbstractThe aim of this study was to evaluate the antibacterial effect of conventional glass ionomer cement with the addition of antibacterial constituents in its liquid preparation. Two groups of glass ionomers prepared with propolis and chlorhexidine and a third group without any additive used as control were sterilized by low-temperature hydrogen peroxide plasma sterilizer at the sterilization unit. Seven to eight disk-shaped restorative materials of each group were placed on the Mueller Hinton Agar with sheep blood 5% v/v, on which Streptococcus mutans inoculated. The plates were incubated at 37°C in 5% CO2 for 24 to 48 hours. After 24-hour and 48-hour-incubation, inhibition zone diameters of each restorative materials were measured. No distinct inhibition zone was reported; only a slight zone (6 mm) around the contact surfaces of each material was observed after the 24-hour and 48-hour incubations. No significant difference was observed in the inhibition zone diameters between the two test groups and control. Within the limitations of this study, results revealed that there was no antibacterial difference among glass ionomers prepared with propolis and chlorhexidine.

Titanium Dioxide Nanoparticles and Cetylpyridinium Chloride Enriched Glass-Ionomer Restorative Cement: A Comparative Study Assessing Compressive Strength and Antibacterial Activity.

To evaluate the addition of titanium dioxide (TiO2) nanoparticles and cetylpyridinium chloride (CPC) on the compressive strength and antibacterial activity of conventional glass-ionomer cement (GIC). TiO2 nanoparticles enriched GIC was prepared by adding 3% TiO2 nanoparticles (w/w) into the powder component of conventional GIC. CPC containing GIC was developed by incorporating 1% CPC (w/w) into conventional GIC powder. Samples were segregated into three groups: GIC with 3% TiO2 nanoparticles, GIC with 1% CPC and unmodified conventional GIC. Compressive strength was assessed using the universal testing machine on cylindrical specimens made from each material. Antibacterial activity was assessed by measuring inhibition zones on Mitis Salivarius Bacitracin (MSB) agar inoculated with pure strain of Streptococcus mutans (S. mutans). GIC containing TiO2 nanoparticles exhibited significantly greater compressive strength as compared with CPC and conventional GIC groups (P < 0.01). However, there was no significant difference between the compressive strengths of CPC and conventional GIC group (P >0.05). Antibacterial activity was significantly greater for TiO2 group than conventional GIC (P <0.05). CPC increased the antibacterial activity of conventional GIC, though not significantly. The addition of 3% TiO2 nanoparticles improves the compressive strength of GIC as well as its antibacterial activity against S. mutans.

In vitro and in vivo evaluations of glass-ionomer cement containing chlorhexidine for Atraumatic Restorative Treatment.

Objectives:Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX.Material and Methods:For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05).Results:Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment.Conclusions:The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations.

Antibacterial activity of glass ionomer cement modified by zinc oxide nanoparticles.

This study evaluated the antibacterial activity of zinc oxide nanoparticles incorporated into self-cured glass ionomer cement (GIC) and light-cured resin-reinforced GIC on Streptococcus mutans biofilm. The GICs, Fuji II (GC America) and Fuji II LC (GC America), were incorporated with nanoparticles at concentrations of 0%, 1%, and 2% by weight, and the biofilm maturation time was one and seven days. Circular specimens of each GIC type were prepared. The antibacterial activity was evaluated by determining the number of colony forming units of S. mutans strain per milliliter. Morphology of the biofilm was analyzed by scanning electron microscopy (SEM). The data obtained for each GIC were analyzed by two-way ANOVA (α = 5%). For chemically activated GIC, no significant difference was observed in relation to the time of biofilm maturation (p = 0.744), concentration of nanoparticles (p = 0.966), and their interaction (p = 0.800). The results from analysis of GIC modified by light-polymerized resin showed that only of the maturing time significantly affected the number of adhered cells on the biofilm (p = 0.034, F = 4.778). The more mature the biofilm, higher the number of cells. SEM analysis showed no change in cell morphology in relation to the type of GIC, maturation time, and nanoparticles concentration. We conclude that the inclusion of zinc oxide nanoparticles at concentrations of 1% and 2% by weight into the GICs evaluated here, did not promote their antimicrobial activity against S. mutans.

Antimicrobial Activity of Glass lonomer Cement Incorporated with Chlorhexidine-Loaded Zeolite Nanoparticles.

A functional dental restorative system with antimicrobial properties was developed using zeolite (ZE) nanoparticles (NPs) as a drug delivery carrier. ZE NPs loaded with chlorhexidine (CHX) were prepared using the ionic immobilization method. The resulting CHX-loaded ZE NPs were then incorporated into commercial dental glass ionomer cement (GIC). The average size of the CHX-loaded ZE NPs was about 100 to 200 nm, and the NPs were dispersed homogeneously in the GIC. The in vitro release profile of encapsulated GIC containing CHX showed an early release burst of approximately 30% of the total CHX by day 7, whereas GIC containing CHX-loaded ZE NPs showed a sustained release of CHX without the early release burst in a 4-week immersion study. The agar diffusion test results showed that the GIC incorporated with CHX-loaded ZE NPs showed a larger growth inhibition zone of Streptococcus mutans than GIC alone, indicating that this innovative delivery platform potently imparted antimicrobial activity to the GIC. Moreover, these findings suggest that a range of antimicrobial drugs that inhibit the growth of oral bacteria can be incorporated efficiently into dental GIC using CHX-loaded ZE NPs.

Relationship between fluoride release rate and anti-cariogenic biofilm activity of glass ionomer cements

ObjectivesThe aim of this study was to evaluate acidogenicity and composition of Streptococcus mutans biofilms on glass ionomer cements (GICs) and then to determine the relationship between the anti-S. mutans biofilm activity and fluoride release rate of the GICs. MethodsS. mutans biofilms were formed on discs prepared using five commercial GICs. Acid production and fluoride release rates of the biofilms on the GIC discs during biofilm formation (0–94h) were determined. Next, 94-h-old S. mutans biofilms on GIC discs were analyzed to evaluate the biofilm composition (dry weight, bacterial cell number, and extra-cellular polysaccharide (EPS) amount) using microbiological, biochemical, and confocal laser scanning microscopy (CLSM) methods. Lastly, relationships between the fluoride release rate and changes in acidogenicity and composition of the biofilms were determined using a linear-fitting procedure. ResultsAll of the tested GICs released fluoride ions. Of the GICs, the two that showed the highest fluoride release rates strongly affected acidogenicity, dry weight, and EPS formation of the biofilms. Furthermore, they reduced the bacterial and EPS bio-volumes and EPS thickness. However, the number of colony forming units (CFUs) of the biofilms was higher than that of the control. Generally, changes in the acidogenicity and composition (except for CFU count) of the biofilms on the GICs followed a negative linear-pattern of fluoride release rate-dependence (R=−0.850 to −0.995, R2=0.723–0.990). SignificanceThese results suggest that the anti-cariogenic biofilm activity of GICs is closely correlated with their fluoride release rate during biofilm formation.

Antibacterial activity of selected glass ionomer cements

The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus. Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC), Fuji IX (GC), Ketac Molar (3M Espe) and Ketac Silver (3M Espe). Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep) were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of the Ketac cements inhibited growth of the standard L. casei strain. Antibacterial activity of glass ionomer cements has attracted the interest of scientists in recent years. Most authors, including us, carried out experiments using the agar diffusion method and demonstrated antibacterial activity of glass ionomer cements. Different antibacterial activity of glass ionomer cements, observed in our study and studies of other authors, depended on the evaluated cement, bacterial strain and period of evaluation.

Antibacterial Activity of Triclosan Incorporated Glass Ionomer Cements – An in vitro Pilot Study

The aim of this pilot study was to evaluate the antibacterial activity of glass ionomer cement impregnated with different concentrations (0.5%, 1.25% and 2.5%) of a non releasing bactericide--Triclosan (TC) against two common cariogenic bacteria - Lactobacillus acidophilus and Streptococcus mutans; and to compare Triclosan incorporated GIC with chlorhexidine (CHX) incorporated GIC (2.5%) in terms of Antibacterial activity. Chlorhexidine or Triclosan were added to glass ionomer cement powder to achieve 2.5% CHX--GIC (positive control--Group II), 0.5%, 1.25% and 2.5% TC-GIC (experimental groups III, IV and V respectively) formulations. Restorative glass ionomer cement (Fuji IX GC--Group I) served as negative control. The powder and liquid were mixed and inserted into the wells punched in agar plates (10 mm x 4 mm). The agar diffusion method was used to determine the antibacterial activity of the cements after 1, 7 and 30 days. Mean values were compared between different study groups using One-way ANOVA and Tukey's HSD procedure at a significance level of 5%. Triclosan incorporated GIC was more effective against L. acidophilus and S. mutans than Chlorhexidine incorporated GIC. Triclosan at a concentration of 2.5% was more effective than at lower concentrations. At all time periods studied, the maximum zone of inhibition against L. acidophilus was produced by Group V. Against S. mutans, on days 1, 7 and 30, there was no significant difference between Groups II and IV (p > 0.05), while the other groups showed significant differences. The use of triclosan as an antibacterial additive in GIC holds promise and further clinical research is needed in this direction.

Antibacterial Properties of Fluoride Releasing Glass lonomer Cements (GICs) and Pit and Fissure Sealants on Streptococcus Mutans.

ABSTRACTTitle: Antibacterial properties of fluoride releasing glass Ionomer cements (GICs) and pit and fissure sealants on Streptococcus mutans.Background: Occlusal pit and fissures are the most susceptible sites for dental caries. The clinical effectiveness of GICs and fissure sealants in preventing caries is well-documented, but there is some concern about bacteria left beneath sealants.Objective: (1) Study the antibacterial activity of GICs and pit and fissure sealants. (2) Compare between these materials.Methodology: GICs (Fuji IX GP and Ketac molar) and pit and fissure sealants (Teethmate-F1 and Helioseal-F ). The strains was grown in the Brain Heart Infusion broth and was incubated anaerobically for 18 hours at 37°C and subcultured in MSB agar.Four wells measuring 5 mm diameter was prepared on each agar plate and the prepared materials was placed and further incubated anaerobically for 48 hours at 37°C. The zone of inhibition was measured.Results: All the materials tested showed antibacterial properties to varying levels except; among pit and fissure sealants it is Teethmate-F which showed more antibacterial property.Conclusion: Teethmate-F1 sealant showed more antibacterial property compared to Fuji IX and Ketac molar. Helioseal-F did not show any antibacterial property.

Preliminary work on the antibacterial effect of strontium in glass ionomer cements

Major problems associated with glass ionomer cement (GIC) dental materials are pulpal damage and the development of recurrent caries [1], which are caused by bacterial infection and not by the restorative material itself [2]. Bacteria can enter through the tooth/restoration interface by micro-leakage or it can multiply from single microbes remaining within the smear layer. Secondary caries is a result of these bacteria. Any antibacterial activity imparted by the restorative material will reduce pulpal damage and increase the restoration’s longevity. Although the population of micro-organisms is known to reduce around GIC restorations [3], the available information about the antibacterial effects of GICs is limited in both the number of materials evaluated and the bacteria tested [4]. GICs are being developed for use as in situ medical cements and in these applications the biocompatibility of the cement is important. Fluoride release is known to stimulate apatite deposition in bone [5], but excessive release has been associated with a cytotoxic response in cell culture [6, 7]. While the antibacterial activity of GICs has generally been attributed to fluoride, obtaining a correlation between fluoride release and antibacterial activity is complicated because cements may release other caries inhibitory species such as strontium, zinc and silver ions. The cements studied in this work have been shown to represent model materials of defined chemical composition, which are free of such complications [8]. Fluoride release from these cements is directly proportional to the fluorine content of the glass; fluoride being released principally by an ion exchange process [8, 9]. The purpose of this study was to undertake preliminary analysis of the antibacterial properties of these GICs and then to reevaluate these properties when strontium ions were added. The glasses employed were based on the generic composition: