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PubMed1997

Bone remodeling with resorbable bioactive glass and hydroxyapatite.

Particulate resorbable bioactive glass and resorbable hydroxyapatite did not inhibit the growth of periodontal ligament cells and osteoblasts in cultures. Both cell types promoted the activation of alkaline phosphatase around the surface of bioactive glass particles. When bioactive glass and hydroxyapatite were cultured with peripheral blood lymphocytes/monocytes, the number of nonadherent and adherent cells was the same as observed with a control. Resorbable bioactive glass activated the cells necessary for bone formation better than hydroxyapatite and suppressed the formation of osteoclasts for bone resorption. Resorbable bioactive glass and resorbable hydroxyapatite were found to be harmless to periodontium cells and lymphocytes/monocytes.

Absorption↗
PubMed1979

Adherence of Mycoplasma gallisepticum to glass.

Attachment of washed Mycoplasma gallisepticum cells to glass was quantified with organisms in which membrane lipids were labelled with 3H. Siliconization of the test tubes decreased attachment, while centrifugation increased it. Attachment increased with temperature, decreased with increasing pH and ionic strength of the attachment mixture, but was unaffected by Ca2+, Mg2+ and EDTA. This suggests that ionic bonds, but not salt bridges, participate in the attachment process. Glycophorin, the major receptor responsible for M. gallisepticum attachment to erythrocytes, partially inhibited the attachment of the organisms to glass. However, bovine serum albumin also decreased attachment. Extensive pretreatment of the organisms with trypsin decreased their ability to attach to glass by about 35 to 40%. Trypsin and pronase failed to detach the organisms already bound to glass, suggesting that external mycoplasma cell components, other than membrane proteins, also participate in attachment of the organisms to glass.

Cell Count↗
PubMed2001

Detection of glass patterns by pigeons and humans: implications for differences in higher-level processing.

Glass patterns have been used to examine mechanisms underlying form perception. The current investigation compared detection of Glass patterns by pigeons and humans and provides evidence for substantial species differences in global form perception. Subjects were required to discriminate, on a simultaneous display, a random dot pattern from a Glass pattern. Four different randomly presented Glass patterns were used (concentric, radial, parallel-vertical, and parallel-horizontal). Detection thresholds were measured by degrading the Glass patterns through the addition of random noise. For both humans and pigeons, discrimination decreased systematically with the addition of noise. Humans showed detection differences among the four patterns, with lowest thresholds to radial and concentric patterns and highest thresholds to the parallel-horiZontal pattern. Pigeons did not show a detection difference across the four patterns. Implications for differences in neural processing of complex forms are discussed.

Adult↗
PubMed2006

Slimline vs. glass pH electrodes: what degree of accuracy should we expect?

BACKGROUND: Ambulatory pH monitoring is considered the gold standard for measuring oesophageal acid exposure, however, data comparing antimony and glass electrodes are limited. AIM: To compare the accuracy of the Slimline antimony pH monitoring system and a conventional glass electrode catheter pH monitoring system during ambulatory conditions. METHODS: Eighteen subjects (13 males, 23-45 years) underwent simultaneous pH monitoring using the Slimline antimony pH electrode and MIC M3 glass pH electrode pH monitoring systems for 12 h. Acid exposure was analysed and compared by manual extraction of the data onto an excel spreadsheet. RESULTS: There was no statistical difference in the median per cent time the pH was <4 recorded by the two systems (Slimline, 3%, Glass MIC M3, 2%, P = 0.77) and the correlation was excellent (r = 0.84). The difference in recorded reflux events was also not significantly different between the two systems, with the absolute difference being 23 events (s.d., 26). Point-by-point discrepancy was 28% (s.d., 18%), however, the agreement in terms of reflex events was excellent (Kappa value, 0.89, s.d., 0.09). CONCLUSION: Despite substantial point-by-point disagreement, the antimony Slimline pH catheter compares favourably to the Glass MIC M3 pH catheter in terms of measuring standard pH parameters.

Adult↗
PubMed1991

Microleakage in alloy-glass ionomer lined amalgam restorations after thermocycling.

Marginal microleakage was measured around amalgam restorations lined with alloy-glass ionomer cement and coated with a glass ionomer varnish. Preparations were made in 48 human extracted mandibular molar teeth. Alloy-glass ionomer liners and varnishes were placed into selected preparations. Tytin amalgam was inserted into all of the teeth and left unburnished and unpolished. Half of the total samples were thermocycled for 5 days and the remainder were left in deionized water. The teeth were immersed in a 0.5% methylene blue dye and sectioned vertically with a diamond saw. Microleakage was scored visually at x100 magnification, and the data were analysed using the Mann-Whitney U-test (P less than or equal to 0.05). Thermocycling did not have a significant effect on microleakage, except when both an alloy-glass ionomer liner and varnish were used. Overall, the use of an alloy-glass ionomer liner made the most significant difference in reducing microleakage.

Coloring Agents↗
PubMed1995

The effect of glaze on restorative glass-ionomer cements.

The surface texture changes of three kinds of glass-ionomer cements were compared with various glazed and polished cement surfaces after the initial finishing. Method 1--the glazing agent--was used, and method 2 consisted of four different Shofu Super Snap discs. In method 3 specimens were compressed with a glass plate. The glazed and polished surfaces were used for investigating various properties such as the surface roughness, colour change, gloss, hardness, toothbrush wear, and were also subject to SEM (scanning electron microscope) observation in the laboratory. The period of 48 h after mixing was chosen for the various testing data. The smoothest surface was formed after compression with a glass plate, however, the glazing agent gave the highest gloss surface for glass-ionomer cement. The lower roughness generally observed was for glazing compared to polishing. The glazed surface is effective as a glass-ionomer cement restoration.

Color↗
PubMed1995

The art of stained glass: metaphor for the art of nursing.

The aesthetic is a way of knowing the meaning of and the meaning in the art of nursing. The art of creating stained glass offers a personal metaphor for nursing's essence; the art of caring. Both arts aim to fulfil the potential of their subjects to achieve a harmony that goes beyond their individual components. Stained glass artistry and caring in nursing require technical expertise, yet technical skill and knowledge are not the substance of either art. Both transcend space and time, and the art of stained glass and the art of nursing are influenced by the artist's/nurse's personal, social and cultural history. Just as the artisan transforms the glass and lead and is transformed in the creative moment, so does the caring transaction transform both patient and nurse. This personal reflection explores the nature of caring in nursing as mirrored by the author's work with stained glass.

Art↗
PubMed1994

Comparison of glass-ionomer and resin-based fissure sealants: a 2-year clinical trial.

In recent years, the interest in the use of glass-ionomer materials as fissure sealants has increased. The aim of this study was to compare the retention and caries-preventive effect of glass-ionomer (Fuji III) and resin-based light-cured (Delton) fissure sealants. Three health center dentists applied the sealants to 166 children; glass-ionomer sealants on one side and resin-based sealants on the contralateral side of the mouth. After 2 yr, one pair of molar teeth in the mouths of 151 children was compared. Twenty-six percent of glass-ionomer and 82% of resin-based sealants were totally present (P < 0.001). During the 2 yr, in both groups 4.6% of the sealed surfaces became carious. The results show that the retention of glass-ionomer sealants is markedly inferior to the resin-based sealants. In this study, however, no difference in caries increment on the sealed surfaces was observed. This may be due to the different mechanism of caries prevention for the sealant materials, or to the overall low caries activity of the participants.

Adolescent↗
PubMed1987

Glass fibre irritation and protective creams.

5 commercial products were tested pairwise as prophylaxis against itching and irritation from glass fibres: a commercial cream for glass fibre itching, a silicone spray, an emollient cream, a fatty ointment, and a "cream-ointment". The preparations were found to have very limited value in protection against glass fibre irritation. Some workers even experienced exacerbated itching from all the preparations, including the cream marketed for protection against glass fibre irritation. Only 25% of a group of workers with severe glass fibre itching still used an emollient cream after 12 weeks.

Adult↗
PubMed1990

Microleakage in fissures sealed with resin or glass ionomer cement.

The purpose of this study was to investigate if microleakage occurs in fissures after being sealed with a glass ionomer cement (Fuji III). Ten pairs of contralateral maxillary premolars, to be extracted for orthodontic reasons, were sealed in vivo. Glass ionomer cement was randomly used on one tooth and diluted composite on the contralateral. An air-polishing instrument was used for cleaning the fissures before sealing them. After 14 days the sealant status was recorded clinically and the teeth were extracted. They were placed in a 0.5% solution of methyl blue, subjected to a thermal cycling procedure, and finally sectioned. The sections were photographed in a stereomicroscope, and two observers recorded the microleakage according to a scoring system. Three glass ionomer sealings were clinically recorded as missing, one partly missing, and six intact, while all the resin sealings were present. Extensive leakage was seen in all glass ionomer specimens with dye penetration throughout the material as well as at the interface between cement and enamel. No leakage was seen in the composite specimens. Remnants of glass ionomer cement were observed in most of the sections from teeth which clinically seemed to have lost the sealing. This study indicates that Fuji III is poorly retained in the fissures, and that the material permits leakage even when it is fully retained. The material may, however, prevent caries by release of fluorides, and the fact that remnants of cement were found in fissures which clinically seemed to have lost it, indicates that this may even occur in cases with loss of retention.

Coloring Agents↗
PubMed2005

Risk factors for failure of glass fiber-reinforced composite post restorations: a prospective observational clinical study.

Glass fiber-reinforced endodontic posts are considered to have favorable mechanical properties for the reconstruction of endodontically treated teeth. The aim of the present investigation was to evaluate the survival of two tapered and one parallel-sided glass fiber-reinforced endodontic post systems in teeth with different stages of hard tissue loss and to identify risk factors for restoration failure. One-hundred and forty-nine glass fiber-reinforced endodontic posts in 122 patients were followed-up for 5-56 months [mean +/- standard deviation (SD): 39 +/- 11 months]. Glass fiber-reinforced endodontic posts were adhesively luted and the core was built with a composite resin. Cox proportional hazards models were used to evaluate the association of clinical variables and failure rate. Higher failure rates were found for restorations of anterior teeth compared with posterior teeth [Hazard-Ratios (HR): 3.1; 95% confidence interval (CI): 1.3-7.4], for restorations in teeth with no proximal contacts compared with at least one proximal contact (HR: 3.0; 95% CI: 1.0-9.0), and for teeth restored with single crowns compared with fixed bridges (HR: 4.3; 95% CI: 1.1-16.2). Tooth type, type of final restoration and the presence of adjacent teeth were found to be significant predictors of failure rates in endodontically treated teeth restored with glass fiber-reinforced endodontic posts.

Adolescent↗
PubMed1991

Comparative study of glass and antimony electrodes for continuous oesophageal pH monitoring.

Oesophageal pH monitoring data are influenced by numerous patient or technique related factors, or both. In this study, data recorded with glass microelectrodes or antimony electrodes, both with external cutaneous Ag/AgCl reference electrodes, connected to two different recording devices are compared. Pearson correlation coefficients regarding the reflux index (% of the investigation time with a pH less than 4) ranged from poor to excellent (0.55 to 1.00). Differences in data recorded with glass electrodes are not significantly dependent on the recording device (r:0.93 to 1.00 for the reflux index). The correlation between data simultaneously recorded with antimony electrodes is lower, although not significantly different for the reflux index (0.90). Correlation between data recorded with glass and antimony probes is rather poor (0.55 to 0.70). Therefore data recorded with antimony electrodes cannot be compared with those recorded with glass electrodes. The mean pH recorded with glass electrodes is lower than that with antimony probes.

Antimony↗
PubMed2004

Point-of-sale glass bottle recycling: indoor airborne exposures and symptoms among employees.

AIMS: To assess the impact of newly introduced point-of-sale glass bottle recycling on indoor air quality and employee health. METHODS: Airborne exposures and both chronic and acute respiratory and somatic symptoms were surveyed among 226 employees at 36 randomly selected liquor stores with bottle recycling and in-house glass breaking. Each store was visited twice; between visits glass breaking was discontinued for one month in half the stores (selected at random), although bottles were still collected and stored on site. Rates of chronic symptoms were compared to an external, unexposed control population. RESULTS: Geometric mean exposure levels were 0.18 mg/m3 for inhalable particulate matter and 3.6 EU/m3 for endotoxin (270 personal samples); 1064 CFU/m3 for viable fungi (648 area samples). Fungal levels were associated with visibly mouldy bottles being broken, outdoor fungal counts, and uncovered glass bins. Exposures were not altered by the intervention of shutting down glass breaking machinery. Compared to controls, employees reported more work related chronic chest tightness and chronic nasal symptoms. Acute chest symptoms were associated with breaking visibly mouldy bottles, but not with measured fungal counts. Inhalable particulate matter levels >0.2 mg/m3 were associated with acute upper airway irritation. Somatic symptoms were associated with measures of psychosocial job strain. CONCLUSION: Results suggest that this type of recycling programme may generate fungal exposures sufficient to elicit upper airway and chest symptoms.

Acute Disease↗
PubMed1991

Fluoride and mutans streptococci in plaque grown on glass ionomer and composite.

The aim of this study was to compare the levels of fluoride and mutans streptococci in plaque grown on glass ionomer (Ketac-Fil) and composite (Silar) restorations in vivo. From tunnels left under the brackets bonded either with glass ionomer or composite, 14-day-old plaque samples were collected 14, 28, and 42 days after bonding. For glass ionomer the mean counts of mutans streptococci in plaque were 0.5 x 10(3), 6.7 x 10(3), and 8.8 x 10(3) CFU at the first, second, and third collection, respectively, whereas for composite restorations the corresponding values were 32.1 x 10(3), 14.6 x 10(3), and 120.6 x 10(3) CFU. For glass ionomer the mean concentrations of fluoride were 19,985, 5,788, and 5,019 ppm at first, second, and third collections of 14-day-old plaque samples, respectively, whereas for composite restorations the mean concentrations of fluoride were about 200 ppm throughout the study. The results show that the fluoride level in plaque growing on glass ionomer is much higher than that on composite restorations which seems to affect the level of mutans streptococci in dental plaque.

Acrylic Resins↗
PubMed1993

In situ anticariogenic potential of glass ionomer cement.

The purpose of this study was to compare the amount of fluoride in plaque formed on glass ionomer cement or composite and to evaluate the effects of fluoride released on growth of cariogenic microflora, fluoride uptake, and secondary caries formation under in situ conditions of a high cariogenic challenge. Ten adult volunteers took part in this crossover study performed in two phases of 28 days. Eighty enamel blocks were randomly restored with glass ionomer cement (Chelon-Fil-Espe) or composite (Silux). During each phase of the study, an acrylic resin appliance, containing four enamel blocks restored with the same material, was constructed for each of the volunteers. During the experimental period, all subjects used fluoride-free dentifrice, refrained from brushing the restored enamel blocks, and immersed the appliances into 20% sucrose solution eight times a day. Fluoride levels, mutans streptococci, and lactobacilli were assessed in dental plaque. Fluoride uptake and microhardness profiles were determined in enamel around the restorations. Statistical analyses indicated a significantly higher level of fluoride (p < 0.05) and a lower level of mutans streptococci plaque formed on glass ionomer cement. Analysis of variance in a split-plot model indicated that in the enamel around the glass ionomer restoration the fluoride uptake was significantly greater (p < 0.025) and the mineral loss significantly lower (p < 0.01). The results show that glass ionomer cement presents a broad anticariogenic effect and may be of value in preventing secondary caries, even under conditions of a high caries risk.

Adult↗
PubMed1993

The effect of glass-ionomer cement on carious dentine: an in vivo study.

The effect of a glass-ionomer cement sealant on carious dentine was investigated clinically and bacteriologically. The study group consisted of 24 molar teeth, with small clinical visible occlusal dentine lesions, in 13 children (aged 7-18 years). Twenty of these molars were filled and sealed with a glass-ionomer cement (Fuji Ionomer Type III) and 4 with a resin sealant (Delton). From each molar, two dentine samples were collected aseptically with a time interval of 7 months. The first sample was taken after opening the lesion just beneath the dentino-enamel junction before application of the filling material (sample A), and the second beneath the removed filling material (sample B) 7 months later. Before collecting sample B the sealant was clinically evaluated and impressions were prepared in order to (re)evaluate the sealants later by scanning electron microscopy (SEM). After taking the second sample, the remaining fissures were opened to a standard depth, the caries which was still present was removed, and a composite resin restoration was applied. In all teeth, more glass-ionomer cement material was found by SEM compared to the clinical evaluation. In both the glass-ionomer- and the resin sealant-treated group, the median value of the total number of microorganisms (CFU) on blood agar was 100 times smaller in the B sample. Microorganisms were found in 90% of the B samples in the group treated with glass-ionomer cement; hard dentine was also found in 45% of the B samples from this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces↗
PubMed1994

Fluoride release and effect on enamel softening by fluoride-treated and fluoride-untreated glass ionomer specimens.

The effect of fluoride application on fluoride release and enamel protection was studied using conventional and light-activated glass ionomers and composite. The specimens prepared from the materials were tested as (1) freshly mixed, (2) aged (29 days), (3) aged and fluoride treated, and (4) aged, fluoride treated, and aged (29 days). For fluoride application, the specimens were immersed in 1.2% NaF solution for 10 min and washed. After handling, the specimens were glued on polished bovine enamel slabs and immersed in lactic acid (pH 5.0) for 3 h. The microhardness of the enamel was measured before and after the acid immersion. Freshly mixed glass ionomers significantly prevented enamel softening. The effect disappeared (conventional glass ionomer) or decreased (light-activated glass ionomer) during aging, but was reestablished by fluoride application. After the subsequent 4 weeks of aging, no significant protective effect could be seen for either of the glass ionomers. The fluoride release, which was greatly increased by fluoride application, was still elevated after 4 weeks of aging for both materials.

Animals↗
PubMed2005

Sol-gel synthesis and photoluminescence of III-V semiconductor InAs nanocrystals embedded in silica glasses.

III-V semiconductor nanocrystals rarely exist as spherical inclusions inside glasses, due to the difficulties during their preparation, such as high toxic reagents or fast oxidation under usual glass technology temperatures. In this paper a sol-gel method for synthesis of InAs nanocrystals embedded in silica glasses was described. Gels were synthesized by the hydrolysis of a complex solution of Si(OC2H5)4, InCl3 x 4H2O, and As2O3. The gels were then heated at 200-450 degrees C in the presence of H2 gas to form fine cubic InAs crystallites. The X-ray diffraction patterns showed four strong peaks from InAs. The Raman spectrum showed InAs longitudinal-optic (233 cm(-1)) and transverseoptic modes (215 cm-(-1)). The size of InAs nanocrystals was found to be from 5 to 30 nm in diameter by transmission electron microscopy. A strong room temperature photoluminescence with peaks at 601 and 697 nm was observed from InAs nanocrystals embedded in silica glasses. The results suggest that it might be possible to synthesize other III-V semiconductor nanocrystals embedded in silica glasses through the sol-gel process.

Arsenicals↗