Types Of Glass Ionomer Cements Research Articles

A long-term study on the setting reaction of glass ionomer cements by 27Al MAS-NMR spectroscopy

Objectives The main objective is the characterization of the setting reaction in glass ionomer cements (GICs) based on experimental glasses using the 27Al magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy in order to understand the crosslinking process during the setting reaction. Methods Three types of GICs which are based on fluoro-alumino-silicate glasses (LG125, ART10, and LG26Sr) were studied using 27Al MAS-NMR to monitor the setting reaction of the cements. Results The result showed clearly the formation of six coordinate, aluminium Al(VI), that crosslink the carboxyl groups in the PAA. The deconvolution study was performed to quantify the amount of each Al species in the cements. The finding showed that composition of original glass has a substantial effect on the setting behavior of the cements. Significance Our data demonstrate that the setting reaction of GICs can be followed by 27Al MAS-NMR spectroscopy discovering the conversion of Al(IV) to Al(VI). Considerable amount of the five coordinate aluminium, Al(V), species was found in the cements aged up to one year. The presence of phosphorus has a strong influence on the setting reaction. The formation of Al–O–P species was postulated to be present in the cement.

Failure behavior of glass ionomer cement under Hertzian indentation

Objective To investigate the load-bearing capacity and failure mode of various types of glass ionomer cement (GIC) under Hertzian indentation, exploring the relationship between the failure behavior and formulation, and examining claims of filler-reinforcement of GIC. Methods Discs 2 mm thick, 10 mm diameter, 8–18 replicates, were fabricated for two filler-reinforced GICs, four unmodified and unreinforced GICs, and four resin-modified GICs, with a dental silver amalgam and a filled-resin restorative material for comparison. Testing was at 23 °C, wet, after 7 d storage at 37 °C in artificial saliva at pH 6, using a 20 mm diameter hard steel ball and filled-nylon substrate ( E: 10 GPa). First failure was detected acoustically; mode was determined visually. At least 1/3 of specimens in each case were examined under scanning electronic microscope for corroboration. Results Reinforced and unmodified-unreinforced GICs were indistinguishable by failure load (one-way analysis of variance, P = 0.425, overall 260 ± 70 N) and mode. Failure loads for resin-modified GICs were 360–1150 N, amalgam ∼680 N, and filled resin ∼1200 N. Resin-modified GICs tended to be tougher (incomplete fracture), all others gave complete fracture (radial cracking). The stronger materials (two resin-modified GICs and filled resin) showed some cone cracking. Significance While resin-modified GICs showed various extents of increase of failure load over that of the plain GICs, consistent with the hybrid chemistry, filler-reinforcement was not evident for the two claimed products, consistent with structural and theoretical expectations.

Antibacterial force of the luting-type of glass ionomer cement toward Lactobacillus species and Streptococcus mutans

Rigid restoration is attached within oral cavity using adhesive cement layer. The hardening adhesive cement fills and tights the rough tooth surface with reciprocal opposing restorations. The luting type of glass ionomer cement was mostly used in the clinic for crown cementation as well as poured restoration. We can be taken a problem how strong is antibacterial effect of the luting type of glass ionomer cement to Lactobacillus species and Streptococcus Mutans. The purpose of the research was to know the antibacterial force of the luting-type of glass ionomer cement toward Lactobacillus species and Streptococcus mutans. This research was a laboratory experiment. The samples of the research were divided into two groups, treated-group (Fuji and Shofu) and controlled-group. The numbers of samples in each group consisted of 7 pieces. Taking 0,5 ml of artificial saliva in which the sample of the luting-type of glass ionomer cement (5 mm in diameter and 2 mm thick) had been immersed and storing it into Petri dish containing warm MRSA and 0,1 ml Lactobacillus sp. using poured technique. The mixture was subsequently incubated, and the colony was counted on the observation of 1st day, 7th day, and 14th day. The data were analyzed using ANOVA and LSD. The result of the research showed that the greatest mean value of the bacterial colony presented in the controlled-group and the smallest was in the group of Shofu. Statistical analysis showed a significant difference (p < 0.05). The released fluoride from glass ionomer cement occurred in the damaging phase caused by polyacrylate that released H+ ion from carboxyl group (COOH). The fluoride influenced the growth of bacteria by decelerating the activity of gycolytic enolase enzyme. The luting-type of glass ionomer cement had antibacterial force toward Streptococcus mutans and Lactobacillus sp. The luting-type of glass ionomer cement of Shofu possessed greater antibacterial force than Fuji and controlledgroup.

The effect of temperature on viscoelastic properties of glass ionomer cements and compomers

The objective of this study was to determine the viscoelastic properties of different types of glass ionomer cements (GICs) and compomers under varying temperature conditions found in the mouth. The materials tested were a conventional GIC (Aqua Ionofil U), a resin modified GIC (Fuji II LC), a highly viscous GIC (Voco Ionofil Molar), and two polyacid modified composite resins/compomers (Glasiosite and Dyract Flow). Six groups of four specimens were prepared from each material. One group was stored dry for 24 h and was subsequently tested dry at 21 degrees C. Each of the remaining five groups was stored for 24 h in distilled water at the temperatures 21, 30.5, 37, 43.5, and 50 degrees C, respectively, and was subsequently tested at that temperature. Shear storage modulus and loss tangent were determined by conducting dynamic torsional loading. Static shear moduli were determined by applying a constant torque (below the proportional limit of the materials) for 10 s and recording the angular deformation of the specimens. Data were analyzed by ANOVA and Duncan's test (alpha= 0.05). It was found that the viscoelastic properties varied significantly (p < 0.05) across the different materials. The compomer Glasiosite, with the highest filler content, and the highly viscous GIC Voco Ionofil Molar exhibited the highest elastic moduli and lowest loss tangents. Viscoelastic properties varied also significantly (p < 0.05) with temperature levels, but changes in the tested region were not indicative of a glass transition. Dynamic shear storage moduli were highly correlated to the static ones. Storage in water lowered the values of elastic moduli.

Dispersive surface properties of glass-ionomer cements determined by inverse gas chromatography

The surface properties of several glass-ionomer cements (GIC), restorative dental materials, (GC-Fuji, Chemadent G-J, Ketac Fil and Ketac Molar) were investigated for the first time by means of inverse gas chromatography. This method enables characterization of surface activity in dispersive (non-polar) and acid–base interactions. The ability of the surface of glass-ionomers to participate in dispersive interactions was expressed by the use of the dispersive component of surface free energy γ s d . This parameter was determined with satisfactory precision, meaning that the values of γ s d can be further used in the discussion of the influence of the type of GIC, its preparation and the storage time on the surface properties. The greatest capacity for dispersive interactions was revealed by Ketac Molar and the lowest by GC-Fuji. Dispersive interactions in the surface activity of glass-ionomers increased with increasing storage time after cement preparation.

Fluoride release from Iraqi made glass ionomer cement. A comparative study

This study was carried out to determine the fluoride release from Iraqi and two imported glass ionomer cements by placing(15) specimens(five for each type of glass ionomer cement) in a polyethylene container filled with deionized water and TISAB. Measurements of fluoride release were taken daily for(8) days following specimen preparation followed by onceweekly for a month Mean daily fluoride release was plotted against time. The results showed that there was a significant difference between Iraqi and Hibond materials within the same period of fluoride release and no significant difference between Iraqi and Degussa cements

The effect of strontium oxide in glass-ionomer cements.

The reaction of strontium oxide powder with poly(acrylic acid) has been studied both alone and within glass-ionomer cements. Reaction was found to be slow and the strontium-carboxylate structure was found to be partially covalent in character, as determined by Fourier transform infrared spectroscopy (FTIR). These are similar to the structures formed by calcium in glass-ionomer cements, but are different from typical monomeric strontium carboxylates, which tend to be purely ionic. Strontium oxide powder introduced in two types of glass-ionomer cements, slowed down the setting reaction at both 21 degrees C and 37 degrees C, but at low levels (5 wt %), increased the compressive strength in both cement formulations studied. However, at higher levels, it was found to decrease the compressive strength. This study confirms the view that strontium is a cement-forming ion; but concludes that, except at very low levels, strontium oxide powder does not improve the properties of glass-ionomer cements.

In vitro bacterial adherence onto pellicle‐coated aesthetic restorative materials

Adhesion of oral bacteria to teeth and restorative materials plays an important role in the pathogenesis of oral diseases. This study investigated the initial adhesion of Streptococcus mutans to enamel and restorative materials. Three types of composites and two types of glass ionomer cements were used. The specimens were coated with freshly collected human parotid saliva. The salivary coated samples were incubated with cell-free glucosyltransferase, and further incubated with sucrose solution. Finally, the specimens were incubated with 3H-thymidine labelled bacteria. Adhesion of the bacteria to the specimens was measured by scintillation counter. SEM observations were performed on each sample. The results showed no significant differences among the materials and the control. These findings can be explained by the pellicle which coated all the specimens. This biofilm, to which the bacteria were adhered and proved to probably masked existing surface properties of the specimens resulting in similar bacterial adhesion.

Adhesion of glass ionomer cement to a ceramometal alloy

Statement of problem. Glass ionomer cements can be used for restoring minor caries lesions, sealing an endodontic access, and repairing defective margins of inlay-onlay restorations. Little information is available on the adhesion between ceramometal alloys and various types of glass ionomer cements. Purpose. The aim of this study was to determine whether the adhesion of glass ionomer cement to the surface of a ceramometal alloy could be enhanced with pretreatment of the alloy surface. Material and methods. Six groups of five specimens were either ground with a diamond bur, sandblasted with aluminum oxide, or ground with a silicon-carbide stone before bonding to either conventional glass ionomer or resin-glass ionomer cements. Resistance to bond failure was tested with a three-point loading test. Results. The results revealed that the greatest resistance to bond failure was obtained by the resin-glass ionomer cement to the sandblasted alloy surface and the least resistance by the glass ionomer cement to the diamond ground alloy surface ( p < 0.001). Both the type of glass ionomer cement ( p = 0.002) and the type of mechanical treatment ( p = 0.001) affected the resistance to bond failure. Conclusions. This study suggests that pretreatment of alloy surfaces with a sandblasting device may be recommended when repairing marginal defects of alloy restorations with glass ionomers. Resin-glass ionomer cements seem to give better adhesion than conventional glass ionomer cements do. (J Prosthet Dent 1997;77:12-6.)

Shear bond strength of glass-ionomer cements to dentin: Effects of dentin depth and type of material activation

The purpose of this study was to determine, through the shear bond strength of in vitro tests, that the type of glass-ionomer cements (conventional or hybrid) and dentin depth (superficial or deep) are factors that may influence the adhesion of these materials to the dentin structure. Specimens of two conventional glass-ionomer cements (Vidrion R® - SS White and Chelon Fil®- Espe) and a hybrid-glass ionomer cement (Vitremer® - 3M) were separated in groups and prepared for the shear bond strength test. The results submitted to statistical analysis were (all values are in MPa): Group I - Vidrion R - superficial dentin 1.97 (&lt;FONT FACE="Symbol"&gt;±&lt;/FONT&gt; 0.56); deep dentin 3.15 (&lt;FONT FACE="Symbol"&gt;±&lt;/FONT&gt; 1.51); Group II - Chelon Fil - superficial dentin 2.43 (&lt;FONT FACE="Symbol"&gt;±&lt;/FONT&gt; 1.43); deep dentin 3.21 (&lt;FONT FACE="Symbol"&gt;±&lt;/FONT&gt; 0.89); and Group III - Vitremer - superficial dentin 7.04 (&lt;FONT FACE="Symbol"&gt;±&lt;/FONT&gt; 2.04); deep dentin 10.30 (&lt;FONT FACE="Symbol"&gt;±&lt;/FONT&gt; 1.99). There were significant differences between dentin depth and type of materials

セメントの粉末粒度分布の変化が合着用セメントの物性に及ぼす影響 特に，支台歯に対する前処置の影響

Our department has been researching the influences of changes in particle size distribution on the physical properties of luting agents. It is said that luting agents are largely affected by contact with water. In the present study, changes in the physical properties after contact with water at the time of cementation were determined in several types of glass-ionomer cement for Luting (Gcement), which differed in particle size distribution, by using an ivory or agar jig. The physical properties of G cement were also examined after pretreatment of the abutment tooth with a surfacetreatment agent and a temporary cement inside the ivory jig.As a result, the greater the content of fine particles was, the greater the compressive strenght, tensile strength and scratch hardness of G cement tended to be. G cement containing high proportions of fine particles was not likely to be affected by water. Pretreatment suchas temporary cementation or surface-treatment prior to cementation for crown or bridge formation was found to be effective for preventing deterioration of the physical properties of G cement.

The glass polyphosphonate cement: A novel glass-ionomer cement based on poly(vinyl phosphonic acid)

This paper outlines research which aimed to develop a new type of Glass-ionomer cement, the glass polyphosphonate cement. The glass polyalkenoate cement, a form of Glass-ionomer cement, is now widely used in dentistry and is based on the reaction between an ion-leachable aluminosilicate glass and an aqueous solution of poly(acrylic acid) or its copolymers. The new cements described in this paper employ a novel polymer, poly(vinyl phosphonic acid), PVPA, as the acidic component. This is a much stronger acid than those used in the glass polyalkenoate cement, and various means must be employed to moderate the reaction in order to obtain a viable cement. These cements show a number of important differences in performance in comparison with PAA-based systems and these differences are discussed in the paper.

Bonding and gap formation of glass-ionomer cement used in conjunction with composite resin.

Glass-ionomer cement has been suggested as liner in cavities restored with composite resin. The purpose of the present investigation was to measure 1) tensile bond strength between etched glass-ionomer cement and composite resin, and 2) gap formation as assessed by wall-to-wall polymerization contraction and by microleakage with a silver nitrate technique. The influence of the following variables was examined: type of glass-ionomer cement and composite resin, duration of acid etching, irradiation time of unfilled and composite resin, preparation of bevel, conditioning with polyacrylic acid, and storing time in water before gap measurement. Bond strengths varied from 0 MPa when etching was omitted to 3.9 MPa after etching. Glass-ionomer cement lining reduced wall-to-wall contraction and penetration of silver nitrate. A positive correlation was found between wall-to-wall contraction and silver nitrate penetration.