Evaluation of glass ionomer luting cements

Abstract – In the present study the three glass ionomer luting cements available on the Scandinavian market in June, 1982 were evaluated by comparison with a zinc phosphate and a zinc carboxylate cement. The following properties were tested: effective maximum grain size, retention, strength, bond strength to dentin, disintegration in and absorption of water and solubility in 0.001 n lactic acid. The glass ionomer cements proved to be fully acceptable luting materials.     

Antibacterial and mechanical properties of arginine-containing glass ionomer cements

ObjectiveThe study investigated the effect of incorporating l-arginine (Arg) in a glass ionomer cement (GIC) on its mechanical properties and antibacterial potential.MethodsPre-determined proportions (1%, 2%, and 4% by wt.) of Arg were incorporated in GIC powder; while GIC without Arg served as control. The flexural strength, nanohardness, surface roughness, elemental analysis using SEM-EDX (n = 6) and F/Arg/Ca/Al/Si release in deionized water for 21 days were assessed. The antibacterial potential was evaluated in a multi-species biofilm model with Streptococcus mutans, Streptococcus sanguinis, Streptococcus gordonii, and Lactobacillus acidophilus for 72 h. Real-time qPCR was used to analyse biofilm bacterial concentrations. Propidium monoazide modification of real-time qPCR was performed to quantify viable/dead bacteria. The pH, lactic acid, ADS activity, and H₂O₂ metabolism were measured. Confocal microscopy was used to investigate the biofilm bacterial live/dead cells, density, and thickness.ResultsThere was no difference in flexural strength among the different groups (p > 0.05). No significant difference in nanohardness and surface roughness was observed between 4% Arg + GIC and control (p > 0.05). The 4% Arg + GIC showed significantly higher F/Arg/Al/Si release than the other groups (p < 0.05), reduced total bacterial concentration and growth inhibition of viable S. mutans and S. sanguinis (p < 0.05). Lactic acid formation for 4% Arg + GIC was significantly higher than 1% Arg + GIC (p < 0.05). The spent media pH of 4% Arg + GIC was higher than the other groups (p < 0.05), with proportionately lower ammonia and higher H₂O₂ released (p < 0.05).SignificanceAddition of 4% l-arginine in GIC enhanced its antibacterial activity via a biofilm modulatory effect for microbial homeostasis, with no detrimental effect on its mechanical properties.     

Effect of green propolis addition to physical mechanical properties of glass ionomer cements

Objective

This study investigated the mechanical properties of glass ionomer cements (GICs) combined with propolis as a natural antimicrobial substance

Material and Methods

Typified green propolis, as an ethanolic extract (EEP) or in the lyophilized form (powder), was incorporated to specimens of Ketac Fil Plus, ChemFlex and Ketac Molar Easymix GICs. For each test, 8 specimens of each material were prepared. For water sorption and solubility tests, specimens were subjected to dehydration, hydration and re-dehydration cycles until a constant mass was obtained for each step. Measurements were recorded using a digital balance of 10^-4 g precision. For the diametral tensile strength test, specimens were tested in a universal test machine at 0.5 mm/min crosshead speed after 24 h storage in deionized water. Data were evaluated by one-way ANOVA and Tukey’s tests (p<0.05).

Results

The addition of propolis to GIC clearly increased water sorption compared to pure material. Solubility was material-dependent and was not clearly evident. For the diametral tensile strength test, association with propolis altered negatively only Chemflex.

Conclusion

It may be concluded that incorporation of propolis to GICs alters some properties in a material-dependent condition.     

The effect of etching on a number of glass ionomer cements

In view of the continuing interest in the use of glass ionomer cements as a dentine substitute or base under composite resins, further investigations were carried out on the effects of the length of time of etching of the surface of the cement prior to the placement of the resin. A number of cements are available on the Australian market which are advocated for use in this technique. Each of them was subjected to etching for periods of 15, 30, 45, or 60 seconds and then stored in water for one week. Examination under a dissecting microscope and a scanning electron microscope revealed some variation in results between the different cements. It would appear that not all those materials presently marketed for this purpose are entirely suitable. Whilst 15 seconds is the preferred time for most cements, some require times up to 60 seconds to achieve the best result. Also, some of the cements showed signs of cracking, expansion and distortion after they had been stored in water for one week to allow for maturation before being prepared for viewing under the SEM. It is suggested that this group of cements is not suitable for the 'sandwich' technique.     

Effect of poly(acrylic acid) architecture on setting and mechanical properties of glass ionomer cements

ObjectiveThis work focuses on the influence of poly(acrylic acid) (PAA) architecture (linear or branched) on setting behavior and compressive strength of glass ionomer cements (GICs).MethodsBranched and linear poly(acrylic acid)s were synthesized according to the Strathclyde methodology or by free radical polymerization. They were characterized by ¹H-NMR spectroscopy and size exclusion chromatography to determine their molecular weight and size distribution. GIC setting was characterized by oscillating rheometry and time-dependent FTIR spectroscopy. In addition, compressive strength was tested on cylindrical samples (6 × 4 mm; n = 8/cement composition) after storage in deionized water at 37 °C for one day.ResultsWe used two different routes to prepare PAA. One direct route in order to provide straightforward access to branched PAA and a two-step approach in order to get more control about the PAA molecular weight using tert-butyl acrylate (tBA) for polymerization with subsequent deprotection. Using the second approach we obtained several linear PAA of which a mixture was used in order to mimic the molecular weight and size distribution of branched PAA. This allowed the direct comparison of properties relying only on the polymer architecture. Comparing linear PAA to branched samples in general led to faster setting but at the same time decreased the compressive strength. Increasing molecular weight of branched PAA resulted in even faster GIC setting while increasing compressive strength and this correlates well with the trends reported for linear PAA in literature. Mixing of branched and linear PAA, however, turned out to be an effective way of tailoring GIC properties. Significance: our results suggest that both molecular weight and dispersity need to be considered when choosing suitable PAA architecture for obtaining specific GIC properties.     

The tensile strength of the union between various glass ionomer cements and various composite resins

Increasing use is being made of the glass ionomer cements as a lining for composite resin restorations, particularly when restoring posterior teeth. It has been suggested that it is possible to obtain a mechanical union between the two materials by etching the surface of the cement. This paper discusses the result of testing a broad variety of combinations of different glass ionomer cements and composite resins that have been reported on previously, and suggests that a number of factors need to be taken into account if the optimum physical properties are to be achieved from the union. There would appear to be four main factors which dictate the final strength of the union. The tensile strength of the cement itself is of primary importance and it seems the wettability of the resin bonding agent is also significant. When using some of the less heavily filled composite resins, the stresses set up by the setting contraction of the resin may be too great and, finally, the more heavily filled composite resins for restoration of posterior teeth often prove difficult to adapt to the underlying cement. With careful clinical handling, the so-called 'sandwich' technique is very useful. However, not all combinations of glass ionomer cement and composite resin will unite with sufficient strength to be successful clinically.     

A 2-year clinical study of two glass ionomer cements used in the atraumatic restorative treatment (ART) technique

The purpose of the study was to evaluate, in a clinical study over 2 years, the deterioration of two glass ionomer cements used with the atraumatic restorative treatment (ART) technique or approach. Fifty-five Fuji IX and 45 ChemFil Superior restorations were placed randomly in 23 adult patients, mainly in small occlusal preparations in molar teeth. The restorations were placed in a dental hospital by one dentist using the ART technique. Photographs, radiographs and replicas were obtained at baseline and subsequent recalls. Both cements were easy to mix and place, but the radiolucency of ChemFil Superior was a disadvantage. Both cements also showed early high losses of sealant and restorative material. After 2 years, 34.5% of the sealants appeared to be completely lost, with caries recorded in 5.3% of the exposed fissures. In some instances, these small lesions may have been present, but not detected clinically, at the time of sealing. Restoration failures of 7.0% were from wear and fracture of the cements and recurrent caries. Mean cumulative wear was 83.1 microm for Fuji IX and 104.0 microm for ChemFil Superior, which was not statistically significant. The cements became darker after their placement to more closely match the restored teeth, but there were few exact matches. There was no surface staining and only minor marginal discrepancies and staining associated with the restorations. Although the short-term clinical performance of the two glass ionomer cements was reasonable, the materials require further improvements in their mechanical properties, to reduce sealant losses and wear. The cements evaluated appear suitable for restricted use only, in posterior teeth.     

A novel antibacterial dental glass‐ionomer cement

Weng Y, Guo X, Gregory R, Xie D. A novel antibacterial dental glass‐ionomer cement.
Eur J Oral Sci 2010; 118: 531–534. © 2010 Eur J Oral Sci This study reports the synthesis and evaluation of a novel non‐leachable poly(quaternary ammonium salt) (PQAS)‐containing antibacterial glass‐ionomer cement. Fuji II LC cement was used for comparison. Compressive strength (CS) and Streptococcus mutans viability were used to evaluate strength and antibacterial activity, respectively. All specimens were conditioned in distilled water at 37°C before testing. After the addition of 1–30% PQAS, both cements showed a reduction in CS, of 25–95% for Fuji II LC and 13–78% for the experimental cement, and a reduction in S. mutans viability, of 40–79% for Fuji II LC and 40–91% for the experimental cement. The experimental cement showed less CS reduction and higher antibacterial activity compared with Fuji II LC. The result also indicates that the cements are permanently antibacterial, with no leaching of PQAS. It appears that the experimental cement is a clinically attractive dental restorative that can be potentially used for long‐lasting restorations as a result of its high mechanical strength and permanent antibacterial function.     

Improvement of the mechanical,tribological and antibacterial properties of glass ionomer cements by fluorinated graphene

Objective

The aim of this study was to improve the mechanical properties, wear resistance and antibacterial properties of conventional glass ionomer cements (GICs) by fluorinated graphene (FG), under the premise of not influencing their solubility and fluoride ion releasing property.

Aesthetic properties of three Type II glass polyalkenoate (ionomer) cements

The aesthetic properties of three recently marketed Type II glass polyalkenoate (ionomer) cements were evaluated in a combined laboratory and clinical study. The materials investigated were Fuji Cap II, ChemFil II in capsules and Ketac-fil Aplicap. The aesthetic properties of a glass ionomer restoration were represented by iss translucency, the colour match with surrounding enamel and marginal adaptation. The translucency of all shades of the selected glass ionomer cements was measured under laboratory conditions and expressed as the optical density on transillumination. Colour match and marginal adaptation were evaluated in a clinical study. Twenty Class V restorations of each of the three products were placed. After finishing, the marginal adaptation was rated by two clinicians and colour slides of the restoration were made. Five clinicians assessed the colour match of the restorations from colour slides. ChemFil II and Ketac-fil Aplicap shades were considerably more translucent than the Fuji Cap II shades. The colour match of the ChemFil II restorations was significantly better than the Fuji Cap II and Ketac-fil Aplicap restorations. Marginal adaptation was judged excellent for all three products.     

The tunnel restoration – nine years of clinical experience using capsulated glass ionomer cements. Case report

The clinical potential of the tunnel restoration is restrained by perceived difficulties of access to proximal caries and lack of long-term clinical data. This paper describes a technique that affords proximal access similar to that of a standard Class II cavity preparation and provides an evaluation of a technique, using capsulated glass ionomer cements. It is supported by more than nine years of clinical experience that confirms the viability of this procedure as an alternative to conventional Class II cavity restorations for initial proximal lesions.     

Demineralisation and remineralisation of dentine caries, and the role of glass-ionomer cements

In accordance with the principles of modern operative dentistry, to conserve tooth structure and to use therapeutic restorative materials, an understanding of the carious process in dentine and the biological properties of glass-ionomer cements (GICs) are necessary. Delineation of the outer necrotic from the inner vital and remineralisable carious dentine allows for the preservation of tooth structure. This delineation is not possible when relying on visual and tactile perceptions, but requires the use of a caries detecting dye. GICs are ideal dentine substitutes because of their anticariogenic properties, stable long-term ionic bonding, and ability to assist the process of remineralization. The range of usage of these restorative materials continues to expand with the development of improved products.