Fuji III vs. Fuji VII glass ionomer sealants--a clinical study.

Glass ionomer cements possess several properties that support their consideration in a wide variety of clinical applications including Pit and fissure sealants. The aim of this study was to compare and evaluate Fuji III and Fuji VII glass ionomer sealants in terms of retention, caries incidence and salivary fluoride release between two groups of children aged 6 and-8 years respectively. One hundred and ten first permanent molars were sealed and the clinical evaluation showed no incidence of caries. There was partial or complete retention of the sealant in 80% of the treated teeth in both groups at the one-year evaluation. Irrespective of the sealant used, the pattern of fluoride release remained consistent, with an initial high fluoride release followed by low prolonged leakage before returning to baseline value at the end of one year.

Reactive fibre reinforced glass ionomer cements.

The mechanical properties of glass ionomer cements used in restorative dentistry reinforced by chopped glass fibres were investigated. Reactive glass fibres with a composition in the system SiO(2)-Al(2)O(3)-CaF(2)-Na(3)AlF(6) and a thickness of 26 microm were drawn by a bushing process. The manufacturing parameters were optimized with respect to maximum strength of the glass fibre reinforced ionomer cements. Powder to liquid ratio, pre-treatment of the glass, grain size distribution and fibre volume fraction were varied. Glass fibre and cement were characterized by X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy techniques, respectively. The highest flexural strength of the reinforced cement (15.6 MPa) was found by compounding 20 vol% reactive fibres and extending the initial dry gelation period up to 30 min. Microscopic examination of the fractured cements indicated a distinct reactive layer at the fibre surface. A pronounced fibre pull out mode gives rise to an additional work-of-fracture contributed by pulling the fibres out of the fracture surface.

Surface roughening of glass ionomer cements by neutral NaF solutions.

The objective of this study was to investigate the effect of repeated applications of a neutral NaF solution on the surface roughness of four conventional glass ionomer cements (GIC) (ChemFil Superior encapsulated, Fuji Cap II, Ketac-Fil and Hi Dense), three resin-modified (RM-) GIC (Fuji II LC encapsulated, Photac-Fil and Vitremer) and one polyacid-modified composite resin (PAM-C) (Dyract). Matured specimens were four times alternately eluted in water and exposed to 2% neutral NaF aqueous solutions for 1h. Control specimens were only subjected to elution in water for the same time period. After the treatment the surface roughness R(a) was determined using non-contact surface profilometry and selected samples were examined with SEM. Except for the PAM-C, R(a) increased drastically for the fluoride-treated samples compared to water-stored samples, the effect being most pronounced for the GIC. Surface roughening apparently is caused by a progressive disintegration or chemical erosion of the polysalt matrix of (RM-)GIC.

A hybrid zinc-calcium-silicate polyalkenoate bone cement.

A novel bone cement composed of sintered zinc-calcium-silicate phosphate and hybrid polyalkenoates has been developed. Synthesis and formulation of glass fillers, monomers and polymers as well as formulation of the cement were described. The effects of sintering, polymer content, glass powder/polymer liquid (P/L) ratio and comonomer on compressive strength (CS) and curing time (CT) were investigated. The effects of P/L ratio and comonomers on shrinkage as well as exotherm were also studied. Results show that the experimental cement was 61% higher in CS, 10% lower in diametral tensile strength, 35% lower in flexural strength, 62% less in exotherm, and 68% less in shrinkage, compared to conventional polymethylmethacrylate cement. With increasing polymer content and P/L ratio in the cement formulation CS of the cement increased but CT decreased. Curing time, shrinkage and exotherm of the cement decreased with increasing P/L ratio. It appears that this novel cement may be a potential candidate for orthopedic restoration if its biological performance is good and formulation is optimized.

Repairability of type II glass polyalkenoate (ionomer) cements.

Two Type II glass polyalkenoate (ionomer) cements were evaluated for their repairability by measuring tensile bond strength of new material added to previously placed cement. Variables included time of repair (20 min vs. 24 h) and surface condition prior to repair (smooth and unetched, smooth and etched, rough and unetched, rough and etched). Failures were evaluated using light microscopy and categorized as cohesive, adhesive, or mixed. Scanning electron microscopy was employed to view the cement surfaces following each of the four pretreatments. Surface pretreatment was found to significantly affect both materials when repaired at 20 min (P less than 0.05). The highest bond strength was achieved when bonding to the smooth, unetched surface. Surface pretreatment did not significantly affect bond strength when the cements were repaired at 24 h (P greater than 0.05). Tensile bond strengths were greater for repairs made at 20 min than for those made at 24 h, but the differences were not always statistically significant.

New direct restorative materials. FDI Commission Project.

People worldwide have become increasingly aware of the potential adverse effects on the environment, of pollution control and of toxic effects of food, drugs and biomaterials. Amalgam and its potential toxic side effects (still scientifically unproven) continue to be discussed with increasing controversy by the media in some countries. Consequently, new direct restorative materials are now being explored by dentists, materials scientists and patients who are searching for the so-called 'amalgam substitute' or 'amalgam alternative'. From a critical point of view some of the new direct restorative materials are good with respect to aesthetics, but all material characteristics must be considered, such as mechanical properties, biological effects, and longterm clinical behaviour.

Glass ionomer cements in pediatric dentistry: review of the literature.

Glass ionomer cement systems have become important dental restorative and luting materials for use in preschoolers, children and teenagers. These materials form chemical bonds to tooth structure, are biocompatible, release fluoride ions for uptake by enamel and dentin, and are able to take up fluoride ions from dentifrices, mouthwashes, and topically applied solutions. Unlike early glass ionomers, the new cement systems are easy and practical to use. Resin-modified glass ionomer cements not only have improved physical characteristics, but the photopolymerizable resin component reduces initial hardening time substantially. This article reviews the development and history of glass polyalkenoate cement systems and their ongoing role in dentistry for children.

Selection of restorative materials for the atraumatic restorative treatment (ART) approach: a review.

The atraumatic restorative treatment (ART) technique or approach for the restoration of primary and permanent teeth has been widely adopted in, but not limited to, developing countries. However, the requirement for the placement of the restorative materials under often less-than-ideal conditions imposes significant restrictions on their selection; and there have been very few randomized clinical trials or reports comparing different types of restorative materials and treatments. Although conventional glass-ionomer cements (GICs) have relatively poor mechanical and adhesive strengths, their satisfactory biological features, ease of use, and low costs are distinct advantages. Most of the published reports of the clinical performance of the newer, high-strength esthetic conventional GICs specifically marketed for the ART approach have been from short-term studies. Satisfactory clinical performance has been demonstrated for single-surface posterior restorations only, over three years. Findings indicate that further improvements in restorative materials are still required for their use with the ART approach, together with further clinical investigations of the remineralization of shallow open caries lesions, as an alternative to placing definitive restorations.

Glass-ionomer (Polyalkenoate) cements. Part 1. Development, setting reaction, structure and types.

The unique properties of the glass-ionomer (or polyalkenoate) cement have widened the compass of restorative and preventive dentistry and changed traditional practice methods. Glass-ionomer cements are the reaction product of an aluminosilicate glass and a polyacid, for example poly (acrylic acid).

Dentin bonding agents and resin cements--current status.

Contemporary restorative dentistry is a rapidly evolving science which challenges the progressive clinician with a plethora of "new and improved" products. Sound product choices should be couched in the prudent consideration of well conducted in vitro and in vivo product research. This review shall list the most recent product developments in dentin bonding agents (fifth generation agents), resin-containing dental cements and the newest generation of dental cements i.e., resin-ionomer dental cements.

Hibridación a esmalte y dentina de los ionómeros de vidrio de alta densidad, estudio con MEB / Enamel and dentin hybridization of high density glass ionomers: a SEM study

De acuerdo con la filosofía de la odontología de mínima intervención, los ionómeros de vidrio están resurgiendo en la odontología restauradora por sus ventajas actuales: dureza, estética y liberación activa defl úor. En la actualidad se ha comprobado mediante estudios y trabajo clínico que estos nuevos ionómeros de vidrio llamados ionómeros de alta densidad tienen un periodo de duración signifi cativo similar a las resinas, pero con más ventajas y con una muy simplifi cada técnica de colocación. El objetivo de este estudio es analizar la adhesión yadaptación marginal de cuatro ionómeros de vidrio de alta densidad, alesmalte y dentina. Material y métodos: Se seleccionaron 16 primeros premolares. A cada uno se le aplicó la preparación convencional de cavidad clase uno de Black de 2 mm de altura por 2 mm de ancho. Se acondicionó la cavidad (esmalte y dentina) con ácido poliacrílico al 10 por ciento por 10 segundos, posteriormente se lavó y secó generosamente y se colocaron los ionómeros de vidrio. Se dividieron en cuatro grupos: 1. Ionofi l Molar® (VOCO), 2. Ketac Molar® (3M ESPE), 3. EQUIA FiL® (GC) y 4. EQUIA Forte® (GC). En la parte final de la obturación,una vez seleccionadas y preparadas las muestras, se analizaron bajo el microscopio electrónico de barrido (MEB). Resultados: Las características encontradas en los cuatro grupos fueron: la integración del ionómero de vidrio a la dentina resultó mejor que al esmalte. Los rellenos inorgánicos de estos materiales se apreciaron mejor definidos en los últimos dos grupos. La adaptación al material de restauraciónse observó bien ajustada en el interior de la cavidad. La formación dehibridación en el esmalte y la dentina fue mejor en los grupos 2, 3 y 4. Conclusión: De los cuatro grupos estudiados el EQUIA FiL y el EQUIA Forte fueron los que presentaron excelente adaptación marginal e hibridación al esmalte y dentina.

According to minimal invasive dentistry philosophy glass ionomers,are making a comeback in restorative dentistry, due to their actualadvantages like: hardness, aesthetics and active fl uor liberation. Nowit has been demonstrated, thanks to studies and clinical trials, thatthe new glass ionomers called high-density glass ionomers have animportant clinical time span, similar to resins, with more advantages;and with a very simplifi ed placement technique. The aim of this studyis to analyze the adhesion and marginal adaptation of four high-densityglass ionomers to the enamel and dentin. Material and methods: 16fi rst premolars were selected. To each one was made the conventionalpreparation class, one cavity of Black of 2 mm of height by 2 mm ofwidth. The cavity (enamel and dentin) was conditioned with 10%polycyclic acid for 10 seconds, then washed and dried generously; andthe glass ionomers were placed. They were divided into four groups; 1.Ionofi l Molar® (VOCO), 2. Ketac Molar® (3M ESPE), 3. EQUIA FiL®(GC), 4. EQUIA Forte® (GC). At the end of the obturation. When thesamples were already selected and prepared, were analyzed by scanningelectron microscopy (SEM). Results: The characteristics found in thefour groups, were as follows: the integration of glass ionomer withthe dentin, was better than the enamel. The inorganic fi llings of thesematerials are better defi ned in the last two groups. The adaptation ofthe restorative material is well observed inside the cavity. The formationof hybridization in the enamel and the dentin, were better in groups2, 3 and 4. Conclusion: Of four studied groups: those that presentedexcellent marginal adaptation, hybridization to the enamel and dentin,were EQUIA FiL and EQUIA Forte, noting that those of group 4(EQUIA Forte) resulted in having the best marginal adaptation, thanany other glass ionomer included in this study.

Glass-ionomer cements as restorative and preventive materials.

This article focuses on glass-ionomer cement (GIC) and its role in the clinical management of caries. It begins with a brief description of GIC, the mechanism of fluoride release and ion exchange, the interaction between GIC and the external environment, and finally the ion exchange between GIC and the tooth at the internal interface. The importance of GIC, as a tool, in caries management, in minimal intervention dentistry (MI), and Caries Management by Risk Assessment (CAMBRA) also will be highlighted.