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PubMed1975

[Studies on soft tissue reactions to implantation of glass ceramics (author's transl)].

This report describes the implantation of glass and glass-ceramics into soft tissues. These experiments revealed that our new glass and glass-ceramic materials are well compatible with soft tissues. The fibrous membrane surrounding such an implantat consists of normal dense collageneous connective tissue. The cells are fibroblasts and fibrocyt-like cells without any abnormal morphology. Macrophages could not be detected. However, the degree of implants solubility must be chosen with care, because high solubility of the implant increases the reaction of the surrounding soft tissues. The described materials are also compatible with osseous tissues. In our previous experiments we have already pointed out, that bonding developed between glass material and bone. Few weeks after implatation we have seen mature lamellar homegeneously mineralized bone opposed to the implant. There was no fibrous membrane between implant and bone. Longtime studies show that hitherto the described bonding exists about 2 years.

Animals↗
PubMed2000

Consumer perception of risk associated with filters contaminated with glass fibers.

The filters in Eclipse, a new cigarette-like smoking article marketed by R. J. Reynolds Tobacco Company, are contaminated with glass fibers, fragments, and particles. Reported herein are the results of a study in which consumers were questioned about their opinions as to whether exposure to glass fibers in such a filter poses an added health risk beyond that from smoking and whether the manufacturer has an obligation to inform consumers about the glass contamination problem. The study queried 137 adults who were interviewed while waiting at a Division of Motor Vehicles office in Erie County, New York in 1997. All but one person expressed the view that the presence of glass fibers on the filters poses an added health risk beyond that associated with exposure to tobacco smoke alone. Nearly all expressed the position that the cigarette manufacturer has a duty to inform the public about the potential for glass exposure.

Adult↗
PubMedDate not supplied

Demineralization around orthodontic brackets bonded with resin-modified glass ionomer cement and fluoride-releasing resin composite.

PURPOSE: Enamel demineralization adjacent to orthodontic brackets is one of the risks associated with orthodontic treatment. Glass ionomer cements have been shown to decrease enamel demineralization adjacent to brackets and bands but do not exhibit bond strengths comparable to resin composites. The purpose of this in vitro study was to compare a fluoride-releasing resin composite versus a resin-modified glass ionomer cement for inhibition of enamel demineralization surrounding orthodontic brackets. METHODS: Forty-five teeth were randomly assigned to 3 groups of 15 teeth. Fifteen were bonded with Concise (3M), a non-fluoride-releasing resin composite (control); 15 teeth were bonded with Light Bond (Reliance), a fluoride-releasing resin composite; and 15 teeth were bonded with Fuji Ortho LC (GC Corporation), a resin-modified glass ionomer cement. The teeth were placed in an artificial caries solution to create lesions. Following sectioning of the teeth in a buccolingual direction, polarized light microscopy was utilized to evaluate enamel demineralization adjacent to the orthodontic bracket. The area of the lesion was measured 100 microns from the orthodontic bracket and bonding agent. RESULTS: MANOVA (P < .0001) and Duncan's test (P < .05) indicated the resin-modified glass ionomer cement (Fuji Ortho LC) and the fluoride-releasing resin composite (Light Bond) had significantly less adjacent enamel demineralization than the non-fluoride-releasing resin composite control. However, there was no significant difference between the resin-modified glass ionomer cement and the fluoride-releasing resin composite. CONCLUSIONS: Based on the results of this in vitro study, it can be concluded that Fuji Ortho LC and Light Bond exhibit significant inhibition of adjacent demineralization compared to the non-fluoride-releasing control.

Acrylic Resins↗
PubMed1999

Hepatic radioembolization with Yttrium-90 glass microspheres for treatment of primary liver cancer.

OBJECTIVE: To study the clinical results of hepatic radioembolization with Yttrium-90 (90Y) glass microspheres in the treatment of primary liver cancer. METHODS: Seventeen patients with liver cancer were treated with glass microspheres from August 1996 to May 1998. Hepatic radioembolization with 90Y and lipiodol-ultrafluid was used. Percutaneous port-catheter system (PCS) implantations via femoral artery were performed in 12 patients. RESULTS: In the 17 patients, their mean ratio of absorbed doses between tumor and normal liver was 2.4:1. CT showed a significant reduction in tumor size in 11 of the 17 patients. Average survival was 19.5 months. The indwelling catheters of all the 12 patients were patent and no catheter tip locations were found. CONCLUSIONS: 90Y glass microsphere is one of the best radioisotopes. Not only good responses to the therapy of 90Y glass microspheres can be achieved in patients with metastatic liver cancer, but also in those with primary liver cancer, specially the localized or hypervascular mass. The patients with massive arterioportal shunt should not be limited to this form of radiation therapy. The percutaneous PCS implantation via the femoral artery is a new passageway for the treatment of primary liver cancer with 90Y glass microspheres and other interventional therapy.

Adult↗
PubMedDate not supplied

Microleakage of a new improved glass ionomer restorative material in primary and permanent teeth.

PURPOSE: The objective of this study was to assess the microleakage of the new conventional glass ionomer, Fuji IXgp in comparison to another conventional glass ionomer (Fuji II), a resin modified glass ionomer (Vitremer) and a composite resin (TPH) in primary and permanent teeth. METHODS: Twenty-five extracted human premolars and 13 primary molars were used. Preparations were made on the center of the buccal and lingual aspects of the premolars (Group A) and the mesio buccal and disto buccal surface as well as the mesio lingual and disto lingual surface of the primary molars (Group B). Each group was randomly divided into five subgroups of 10 specimens each and restored with a different material following the manufacturer's recommendations. Restorations were subjected to thermocycling followed by microleakage evaluation using 50% silver nitrate and computerized image analysis. RESULTS: Two factor analysis of variance revealed a significant main effect of material (P<0.001), a trend toward a main effect of tooth type (P=0.082) and a significant interaction term P=0.016. Materials were a source of difference, so a one-way ANOVA test was used for both primary and permanent teeth together and for each individual group of teeth. Differences were further examined with a multi-variate analysis using the Scheffe' test for both groups of teeth and each individual group of teeth. Each group of teeth restored with the same material was then analyzed with an Independent Samples t-test which showed that conventional glass ionomer (Fuji II) had more leakage than all other groups (P<0.01). In addition TPH showed more microleakage in primary teeth (P<0.02) and Fuji II showed more microleakage in permanent teeth (P<0.02). CONCLUSIONS: Fuji IXgp behaved similarly to the composite (TPH) and to the resin modified glass ionomer (Vitremer). This is a promising result for this material that is targeted for application in conjunction with the Atraumatic Restorative Technique and minimal intervention treatments.

Analysis of Variance↗
PubMed1996

[Resin-modified glass-ionomers in dentistry].

The resin-modified glass-ionomers contain the essential components of both a conventional glass-ionomer and a visible light-cured resin. They have several advantages like longer working time, shorter setting time, bonding to tooth structure, fluoride-release, better aesthetics than conventional glass-ionomers and ease in use. As disadvantages can be mentioned the polymerisation shrinkage, trapping of air-bubbles, difficulties in colour choice and contouring. A physical and mechanical characterisation was necessary to define the possibilities and limits of these materials. It can be stated that the strength and aesthetic appearance of resin-modified glass-ionomers are less than that of composites, but better than that of conventional glass-ionomers. Clinically, this is expressed in a rough and dull surface compared to a composite restoration. They are not indicated in stress bearing areas. Consequently, they are mainly indicated in cervical class V-restorations in the postcanine region, and probably restorations in pedodontics, geriatric dentistry and for patients with a high caries activity.

Compomers↗
PubMedDate not supplied

Interferon alpha-2a interactions on glass vial surfaces measured by atomic force microscopy.

Atomic force microscopy was used to study adsorption and adhesion peculiarities of interferon alpha-2a on glass and mica surfaces. The specific protein adsorption behavior as a function of the pH value was illustrated on mica by single molecule imaging, while adhesion forces between interferon molecules and inner surfaces of borosilicate glass vials were measured directly under aqueous buffer conditions by force microscopy. We found that the adhesion force on Schott FIOLAX Type I plus was reduced by 40% of the total adhesion force measured on Schott FIOLAX, a standard type I borosilicate glass quality. These results reflect the anticipated superiority of the special "Type I plus" coating over undesired protein adsorption to glass. In addition, this study gives insight into a new method to predict unintended protein adsorption to glass container walls and to characterize the adsorption process by force measurement.

Adsorption↗
PubMed2002

Effect of glass fiber reinforcement on the flexural strength of different denture base resins.

OBJECTIVE: Different types of fibers have been added to polymer materials to improve their mechanical properties. Glass fibers have been used in either continuous or woven form as a strengthening material. The aim of this study was to investigate the effect of a new glass fiber reinforcement system on the flexural strength of three different denture base resins (heat polymerized, autopolymerized, and photopolymerized). METHOD AND MATERIALS: Ninety specimens were formed in a specially designed mold to produce identical specimens in accordance with each manufacturer's recommendations. RESULTS: The fibers of Stick and Stick Net were well impregnated with the resin of polymer matrix. Stick and Stick Net reinforcement significantly enhanced the flexural strength of the tested specimens. In all groups, specimens reinforced with Stick glass fibers exhibited the highest flexural strength, followed by Stick Net glass fibers. The control group specimens without fiber exhibited the lowest values. CONCLUSION: The process of reinforcement of denture base resins with glass fiber may be a useful means of strengthening denture bases beyond their normal limits.

Acrylic Resins↗
PubMed2002

Fluoride release and caries inhibition associated with a resin-modified glass-ionomer cement at varying fluoride loading doses.

PURPOSE: To measure, over time, the release of fluoride from a resin-modified glass-ionomer cement, loaded with different levels of fluoride, then to evaluate the adjacent dentin demineralization inhibition relative to these fluoride levels. MATERIALS AND METHODS: (Phase I) 25 standardized discs were fabricated from a non-fluoridated resin-based composite (control), resin-modified glass-ionomer cement and resin-modified glass-ionomer cement loaded with sodium fluoride at 1%, 2% and 3% by weight fluoride. Fluoride release was evaluated over 30 days. (Phase II) 50 restorations, from the materials listed in Phase I, were placed as Class V restorations in teeth, the teeth were acid-challenged, then dentin margins adjacent to restoration margins were evaluated for demineralization. RESULTS: As sodium fluoride additions increased, fluoride release increased. Evaluation of demineralization indicated the resin-modified glass-ionomer cement inhibited adjacent demineralization in a direct relationship with sodium fluoride concentration where 3% fluoride exhibited significantly less adjacent demineralization than all other groups; 2% and 1% fluoride exhibited significantly less adjacent demineralization than the non-loaded resin-modified glass-ionomer cement and non-fluoridated resin-based composite control (P< 0.05).

Acid Etching, Dental↗
PubMedDate not supplied

Glass ionomer cements.

Glass ionomer cements have been used in pediatric restorative dentistry for 20 years. Their usefulness in pediatric restorative dentistry is preferential relative to other materials because of their fluoride release, chemical adhesion to tooth structure, and availability to use in a variety of clinical scenarios. This paper reviews the use of glass ionomer materials in pediatric restorative dentistry. The paper provides a look at glass ionomer cements' use as sealants and restorative materials and examines glass ionomers as adhesives, as a stand-alone material and in the sandwich technique. This paper also provides a useful guide to connecting to other references regarding specific aspects of glass ionomers in children.

Cementation↗
PubMed2003

[The inhibitory effect of glass ionomer cement for orthodontic bonding on bacteria].

OBJECTIVE: To prove the inhibitory effect of glass ionomer cement for orthodontic bonding on bacteria. METHODS: Twenty-two persons were chosen randomly. In vivo, with the split-mouth technique, brackets were bonded with glass ionomer cement or composite resin respectively. Plaque samples were taken from the area of the adhesive one month after the placement of brackets and incubated for microbiologic analysis. RESULTS: There was no significant difference in the amount of total anaerobic bacteria with the two materials. There were also no obvious reduction of the numbers of S. mutans (the composite: 2.4 x 10(10) CFU/L, the glass ionomer cement: 2.8 x 10(10) CFU/L, P = 0.673) and its proportion (percentage of total CFU) with the use of glass ionomer cement compared with the composite. CONCLUSIONS: There was no long term inhibitory effect on bacteria adjacent to glass ionomer cement for orthodontic bonding.

Adolescent↗
PubMedDate not supplied

The effect of incremental versus bulk fill techniques on the microleakage of composite resin using a glass-ionomer liner.

Incremental placement of composite resin has been suggested to reduce microleakage, particularly at the gingival margin of class 5 cervical restorations. It has become clinically advantageous to place a glass-ionomer liner over dentin to further minimize microleakage resulting from a bond between the dentin and glass ionomer, and glass ionomer and resin. The objective of this study was to compare the microleakage behavior of three hybrid composite/bonding agent systems using bulk and incremental filling techniques utilizing a glass-ionomer liner. This was accomplished in vitro using freshly extracted bovine incisors and a Ca45 radioisotope and autoradiography. Sixty bovine incisors were divided into six experimental groups of 10 specimens per group. Class 5 preparations were cut at the cementoenamel junction and restored with the appropriate combination of Herculite XR/Bondlite, P50/Scotchbond 2, or Pertac Hybrid/Pertac Bond. All teeth were lined with the glass ionomer Ketac Bond before the final restoration was placed. The samples were finished and stored for 24 hours in distilled water before thermocycling. The samples were tested for microleakage using a Ca45 radioisotope technique and autoradiography. Incisal (enamel) and gingival (dentin) margins were scored separately for microleakage but grouped for statistical analysis. Results were analyzed using the Kruskal-Wallis H test. Pertac Hybrid exhibited more leakage than Herculite XR or P50. The difference between microleakage of bulk and incremental filling techniques was only significant for P50.

Analysis of Variance↗
PubMedDate not supplied

Leakage patterns associated with glass-ionomer-based resin restorations.

This study compared microleakage patterns for glass-ionomer-cement-based resin systems with and without a separating agent placed between the glass ionomer and resin. Results indicated significant leakage (100%) at the dentin glass-ionomer interface for specimens without a separating agent. Those with a separating agent showed almost no leakage between the dentin and glass ionomer (10%) and some leakage at the resin/glass ionomer interface (40%). These results suggest that the forces of polymerization shrinkage are stronger than the chemical bond between glass-ionomer cement and dentin. This bond fails during resin polymerization, eliminating any supplementary retention gained through chemical adhesion to dentin and opening a pathway for microleakage.

Chi-Square Distribution↗
PubMed2003

Dimensional changes and water sorption of two acrylic polymer materials reinforced with glass fibres.

The purpose of this study was to examine the effect of glass fibre reinforcement on the dimensional changes and water sorption of a heat-polymerising denture acrylic polymer and a microwave-polymerising denture acrylic polymer. Fifteen specimens from each group were prepared with 2% by weight (18 mg) E-glass fibre and 15 without glass fibre. The dimensional change measurements were made at three different stages on the 60 specimens. The water sorption calculations were made on specimens immersed in distilled water at 37 degrees C +/- 1 degree C for 0, 1 and 7 days. Glass fibre reinforcement and processing method do not affect the dimensional change of test specimens, but as the time increased the dimensional change decreased. The glass fibre reinforcement decreased water sorption, but the two processing methods failed to show a significant difference.

Absorption↗
PubMedDate not supplied

Biocompatibility of a flowable composite bonded with a self-etching adhesive compared with a glass lonomer cement and a high copper amalgam.

This study evaluated the pulpal response and in-vivo microleakage of a flowable composite bonded with a self-etching adhesive and compared the results with a glass ionomer cement and amalgam. Cervical cavities were prepared in monkey teeth. The teeth were randomly divided into three groups. A self-etching primer system (Imperva FluoroBond, Shofu) was applied to the teeth in one of the experimental groups, and the cavities were filled with a flowable composite (SI-BF-2001-LF, Shofu). In the other groups, a glass ionomer cement (Fuji II, GC) or amalgam (Dispersalloy, Johnson & Johnson) filled the cavity. The teeth were then extracted after 3, 30 and 90 days, fixed in 10% buffered formalin solution and prepared according to routine histological techniques. Five micrometer sections were stained with hematoxylin and eosin or Brown and Brenn gram stain for bacterial observation. No serious inflammatory reaction of the pulp, such as necrosis or abscess formation, was observed in any of the experimental groups. Slight inflammatory cell infiltration was the main initial reaction, while deposition of reparative dentin was the major long-term reaction in all groups. No bacterial penetration along the cavity walls was detected in the flowable composite or glass ionomer cement except for one case at 30 days in the glass ionomer cement. The flowable composite bonded with self-etching adhesive showed an acceptable biological com- patibility to monkey pulp. The in vivo sealing ability of the flowable composite in combination with the self-etching adhesive was considered comparable to glass ionomer cement. Amalgam restorations without adhesive liners showed slight bacterial penetration along the cavity wall.

Analysis of Variance↗
PubMed2003

Investigation of the bone tissue response to glass-ionomer microimplants in the canine maxillary alveolar ridge.

This paper reports the results of experimental use of glass-ionomer microimplants in the augmentation of the maxillary alveolar ridge in dogs. The study included ten adult mongrel dogs 5 years of age, weighing between 50 and 70 pounds (25-30 kg), divided into 2 groups of 5 dogs each. In both groups, the maxillary 4th premolar and 1st molar were removed after the elevation of a buccal mucoperiosteal flap. The alveolar bone adjacent to the extracted teeth was also removed. In the experimental group (5 dogs), Ionogran a glass-ionomer microimplants (GIMIs) (Ionogran particle size of 0.5-1.0 mm, IONOS Medizinische Produkte GmbH & Co. KG, D-8031 Seefeld, Gemany) were used for augmentation and were inserted in the created defects. The extraction sockets and bone defects were augmented with an average amount of 2 g of GIMIs. In the control group, the bone defects were left unfilled as a control for bone healing. Histological examination showed that the glass-ionomer microimplants were extremely osteoconductive and inert materials. Stimulation of growth of new bone tissue in contact with the glass-ionomer microimplants was evident. No inflammatory cells were detected on or adjacent to the GIMIs. In the control group, incomplete bone healing with fibrous scar tissue and inflammatory cells was noted. These results indicate that glass-ionomer microimplants represent highly osteoconductive and biocompatible materials for use in bone surgery.

Aluminum Silicates↗
PubMed2004

Compressive strength of glass ionomer cements with dental antibacterial agents.

Glass ionomer cements have been suggested for obturating carious teeth that have been prepared with dental hand instruments. In such cases, carious dentine may be inadvertently or deliberately left in situ. The residual bacteria may, over time, lead to secondary caries and restoration failure. Benefit may be gained from combining antibacterial agents with the glass ionomer cement to control residual bacteria. The aim of this study was to investigate the effects on the compressive strength of glass ionomer cement combined with oral antibacterial agents. Cationic antibacterial agents; chlorhexidine hydrochloride, cetylpyridinium chloride and cetrimide were added to the powder and benzalkonium chloride, a liquid, to the liquid of Fuji IX glass ionomer cement. These were prepared to concentrations of 1, 2 and 4 per cent by weight of the glass ionomer cement and compared to Fuji IX with no antibacterial agent. Test specimens were subjected to a compressive force to failure. Multiple analysis of variance showed highly significant reductions in compressive strength (p < 0.01) between the test materials and control group apart from one per cent benzalkonium chloride. Increasing concentration of the antibacterial agent had increasing adverse effects on the physical properties. The addition of the antibacterial agents tested to Fuji IX reduces the seven-day compressive strength which may affect the clinical performance of the material.

Analysis of Variance↗
PubMed2004

Near net-shape fabrication of hydroxyapatite glass composites.

Near net-shape fabrication of hydroxyapatite (HA) glass composites has been attempted by infiltrating a glass into porous HA performs. Main efforts were put to develop glasses that are chemically compatible with HA at elevated temperatures. After extensive investigations in the phosphate and borosilicate systems, glasses of (50-55)SiO2-(20-25)B203-(10-20)Li2O-(0-6)CaO (wt%) composition were successfully developed. The glass shows good chemical compatibility with HA at elevated temperatures. Dense HA/glass composites can be fabricated at 850-950 degress C by the melt infiltration process. Investigations demonstrated a good near net-shape capability of the process, where the linear shrinkage induced by the infiltration process is less than 0.1%. Preliminary mechanical tests showed that the fracture strength and toughness of the infiltrated HA/glass composite are comparable with dense HA.

Biocompatible Materials↗