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PubMedDate not supplied

Effects of pH on the surface texture of glass ionomer based/containing restorative materials.

This study determined the effect of pH on the surface texture of commonly used posterior glass-ionomer based/containing restorative materials. The materials evaluated included a compomer (Dyract AP), a giomer (Beautifil) and two highly viscous glass ionomer cements (Fuji IX and Ketac Molar). A resin composite (Esthet-X) was used for comparison. Forty-two specimens (3-mm wide x 3-mm long x 2-mm deep) were made for each material. The specimens were divided into six groups and conditioned in the following solutions at 37 degrees C for one week: Citric acid (pH 2, 3, 4, 5 and 6) and distilled water (pH 7). After conditioning, the surface roughness (Ra, microm) of each specimen was measured using a surface profilometer (Surftest, Mitutoyo Corp, Tokyo, Japan). Data was analyzed using one-way ANOVA and Scheffe's test at a significance level of 0.05. The effects of pH on the surface texture of glass-ionomer based/containing restoratives were material dependent. Ra values ranged from 0.02 microm to 0.15 microm and 0.03 microm to 4.40 microm for pH 7 and 2, respectively. With the exception of the composite, the surface roughness of all materials evaluated was significantly affected by acids of low pH. The surface texture of highly viscous glass ionomer cements deteriorated significantly when conditioned in solutions of low pH, which makes them more susceptible to clinical failure.

Analysis of Variance↗
PubMed2005

[Microstructure and adhesion of HAP-glass-alumina composite gradient bioceramics coating].

HAP-Glass-alpha-Al2O3 gradient coating on alumina ceramics substrate was prepared by multi-layer slurry-dipping and sintering process, effects of the composition of the coating on the microstructure and adhesion strength of the gradient coating were studied. R2O-Al2O3-B2O3-SiO2 system glass with low softening temperature and thermal expansion was used in the gradient coating. The composition of the coating was varied from interface to surface layer, i.e. the HAP concentration increased and glass concentration decreased gradually from the under layer to the surface layer. A suitable amount superfine alpha-Al2O3 was added in the gradient coating to reinforce the bonding strength between the coating and substrate. The results show that the use of R2O-Al2O3-B2O3-SiO2 system glass is propitious to sintering the coating at low temperature and to combination between the coating and substrate. The addition of superfine alpha-Al2O3 can reinforce the bonding strength between the coating and substrate, the highest bonding strength is about 48.2 MPa.

Adhesiveness↗
PubMedDate not supplied

Intracoronal sealing comparison of mineral trioxide aggregate and glass ionomer.

OBJECTIVE: The purpose of this study was to determine the effectiveness of mineral trioxide aggregate and glass ionomer when placed coronally as double-sealing materials over gutta percha. METHOD AND MATERIALS: Seventy extracted anterior teeth were cleaned, shaped, and obturated with gutta percha and Sealapex. After removing 4 mm of coronal gutta percha, the teeth were randomly divided into 3 groups. In two experimental groups of 30 teeth each, 4 mm of either mineral trioxide aggregate or glass ionomer was placed in the chamber over gutta percha. A positive control group of 5 teeth received no barrier. A negative control group of 5 teeth was covered completely with sticky wax. All teeth, except the negative controls, were covered with 2 layers of sticky wax except for the access openings. Teeth were immersed in Pelikan ink for 48 hours, and then were decalcified, dehydrated, and cleared. Leakage into the canals was measured in millimeters and statistically analyzed between the two experimental groups using the Mann-Whitney test. RESULTS: Results showed that the glass ionomer group leaked significantly more than the mineral trioxide aggregate group (P < .001). CONCLUSION: It was concluded from this study that mineral trioxide aggregate may be preferred over glass ionomer as a seal intracoronally following root canal treatment to prevent coronal microleakage.

Aluminum Compounds↗
PubMed2005

Chlorhexidine-containing glass ionomer cement. A clinical investigation on the fissure caries inhibiting effect in first permanent molars.

UNLABELLED: Glass ionomer cement with addition of chlorhexidine used as a varnish on tooth surfaces has been shown to reduce the number of interproximal mutans streptococci (ms). The effect of a single application of such a varnish containing 2.5% chlorhexidine on occlusal caries development of the first permanent molars on 6-year-old children in a high caries incidence area was investigated. The children were examined according to WHO criteria and 262 children with 2 caries free contra-lateral molars were selected for treatment. Salivary ms samples were collected using the Strip-mutans (SM) method. After brushing the occlusal surfaces with a toothbrush and pumice in water slurry, rinsing and drying with a cotton roll, glass ionomer cement containing chlorhexidine (GI-CHX) and glass ionomer (GI) were applied randomly with a micro brush and the varnish was covered with occlusal wax. At baseline, the mean defs was 18.18 and DMFS was 0.25 and after one year 18.24 and 0.83 respectively. The salivary ms scores were high or very high (SM 2 and 3) in 85.6% at baseline. At the one-year follow up, the GI-CHX and GI materials could not be detected in the fissures. Also, a large number of fissure sealants had been placed in the molars outside the study protocol; thus 4% of the GI-CHX and GI, and 70% of the untreated were sealed at year one. Overall, there was no significant difference between the caries-reducing effect of GI-CHX and GI, but a trend towards a higher effect was seen for GI-CHX. Excluding the sealed molars the reduction was 74% in the GI-CHX-group, and 71% in the GI-group. CONCLUSION: Addition of 2.5% chlorhexidine to glass ionomer did not seem to increase the caries-reducing effect of the varnish in this high caries incidence population.

Anti-Infective Agents, Local↗
PubMedDate not supplied

Inhibitory activity of glass-ionomer cements on cariogenic bacteria.

This study evaluated the antibacterial activity of the glass-ionomer cements Vitrebond (3M ESPE), Ketac Molar (3M ESPE) and Fuji IX (GC America) against S mutans, S sobrinus, L acidophilus and A viscosus, using the agar diffusion test. Inocula were obtained by the seed of indicators cultures in BHI broth incubated at 37 degrees C for 24 hours. Base layers containing 15 mL of BHI agar and 300 microL of each bacteria suspension were prepared in Petri dishes. Six wells measuring 4 mm in diameter were made in each plate and completely filled with one of the testing materials. A 0.2% chlorhexidine solution applied in round filter papers was used as control. Tests were performed 12 times for each material and bacteria strain. After incubation of the plates at 37 degrees C for 24 hours, the zones of bacterial growth inhibition around the wells were measured. Overall, the results showed the following sequence of antibacterial activity: Vitrebond (despite the activation mode) > 0.2% chlorhexidine > Ketac Molar > Fuji IX, according to Kruskal-Wallis and Mann-Whitney statistical tests. This study confirmed significant antibacterial activity for two conventional glass-ionomers and one resin-modified glass-ionomer material. The resin-modified glass-ionomer cement Vitrebond, regardless of the activation mode, presented the best antibacterial activity against S mutans and S sobrinus. The antibacterial activity against A viscosus for Vitrebond was similar to 0.2% chlorhexidine, while light activation reduced its antibacterial activity against L acidophilus.

Actinomyces viscosus↗
PubMed2006

Clinical evaluation of a resin-modified glass-ionomer liner for cervical dentin hypersensitivity treatment.

PURPOSE: To evaluate the effectiveness of two agents for treating cervical dentin sensitivity associated with gingival recession or noncarious cervical lesions. METHODS: 44 patients with at least mild sensitivity affecting cervical dentin were enrolled in a longitudinal randomized clinical trial. A resin-based desensitizer or an experimental glass-ionomer was assigned to treat at most two teeth from each side of the mouth. Sensitivity was assessed by tactile and cold tests, measured with a Visual Analogue Scale at baseline, after treatment, and at 1 week, 1, 3, 6, and 12 months after treatment. Other noteworthy clinical observations were recorded. RESULTS: Both treatments effectively reduced dentin sensitivity (mixed linear model analysis). Sensitivity score for the glass-ionomer was significantly lower than for the resin-based desensitizer after treatment and at all follow-up periods (P < 0.0001). Some overhanging margins were observed in the glass-ionomer group, which could accumulate plaque and cause gingivitis. Despite material loss from some teeth treated with the glass-ionomer, the follow-up sensitivity scores were still lower than baseline scores.

Adult↗
PubMed2006

The underestimation of a glass injury to the hand.

This study sought to ascertain the differences between what is found on an orthopedic preoperative examination of a glass injury to the hand and the actual intraoperative deficiencies noted in the operating room. The cases of 34 patients who presented to our institution for a shattered glass laceration to the hand, forearm, or wrist between 1998 and 2001 were reviewed. The preoperative examination significantly underestimated the amount of damage to tendons, arteries and nerves. The most frequent injury pattern was the flexor digitorum superficialis (34/103 = 33%), the radial artery (7/18 = 39%), and the superficial branch of the radial nerve (7/32 = 22%). A glass injury to the hand can be a deceivingly debilitating and significant injury. The preoperative examination, even when specifically evaluating for deficiencies, significantly underestimates the extent of damage. If glass is implicated as a causative agent, careful orthopedic evaluation and surgical management should be considered even in light of a normal preoperative examination.

Adolescent↗
PubMedDate not supplied

Microscopic evaluation of the interface between glass-ionomer cements and tooth structures prepared using conventional instruments and the atraumatic restorative treatment (ART) technique.

OBJECTIVE: The purpose of this study was to evaluate the effect of cavity preparation using hand instruments and conventional rotary instruments on the bonding of glass-ionomer cements to formerly carious teeth. METHOD AND MATERIALS: In 2 experimental groups (12 teeth each with primary caries) caries was removed and cavities prepared using hand instruments according to the atraumatic restorative treatment (ART) technique or conventional rotary instruments. In the control group (12 caries-free teeth) Class 1 cavities were prepared using conventional instrumentation. Cavities in all teeth were restored with 1 of the commercial glass-ionomer cements designed for use with the ART technique, either Fuji IX (GC) or Ketac Molar (3M Espe). After 21 days of storage in physiologic saline at 37 degrees C, 3 400-microm-thick slices from each tooth were stained using the Mallory method and evaluated using a light transmitting microscope. RESULTS: In all samples, a region of interaction was observed between the cement and dentin and enamel. However, the interface in teeth from which caries had been removed was different from that in the control group. All were stained using Mallory staining, but only teeth which had been carious showed coloration. No differences were found in intensity of color or appearance between the cavity preparation techniques. CONCLUSION: The occurrence of caries in a tooth alters the bonding behavior of glass ionomers to that tooth. The method of caries removal (ART or conventional preparation) does not influence the quality of the interface between a glass ionomer and either dentin or enamel.

Acids↗
PubMed2006

[Investigation of the function of the glass colorant on the machinable infiltrated ceramics color].

OBJECTIVE: To investigae the function of the glass colorant on the color of the machinable infiltrated ceramics(MIC). METHODS: Five kinds of glass with different colorant were infiltrated through the aluminous matrix by heating the components to 1 100 degrees C for 2 hours. The specimens surface was polished, and their thickness was 0.5 mm. RESULTS: The refractive index of the MIC infiltration glass was 1.59691 (587.6 nm, nd) . The most different parameter of the MIC color were L*, then a*, and b* had little difference . The parameters of the color space of MIC were: L*(64.55-71.46), a*(3.35-7.38), b*(10.00-12.41), Ca*b*(11.38-13.95), ha*b*(54.07-73.00). These were almost close to the color parameters of Vita In-ceram. CONCLUSION: This experiment proved that the glass colorant was changed the MIC color parameters, and the main function was on L*, then a*. The ceramic color was up to the requirement of clinic.

Aluminum Oxide↗
PubMed2006

Cyclic loading of endodontically treated teeth restored with glass fibre and titanium alloy posts: fracture resistance and failure modes.

The aims of this in-vitro investigation were to compare the fracture resistance and the failure modes of endodontically treated teeth restored with glass fibre-reinforced posts with those of teeth restored with titanium-alloy posts. A total of 60 single-rooted human mandibular premolars were endodontically treated. The teeth were divided into two experimental and one control group. Post spaces 9mm long were prepared in the roots of the experimental groups in which glass fibre-reinforced posts (Group A) and titanium-alloy posts (Group B) were cemented. In the control group (Group C), no post was inserted. The specimens were stored in normal saline for a period of three weeks before being intermittently loaded at an angle of 30 degrees degrees to the long axis of the tooth at a frequency of two loads of 40N per second. Log-rank test used for the overall analysis revealed that there was no significant difference of fracture resistance between teeth restored with glass fibre-reinforced posts (Group A) and titanium-alloy posts (Group B). The survival of the control group was found to be significantly inferior to that of the experimental groups. There was no significant difference in the number of failures between the two experimental groups. There was significantly more core and post failure for the glass fibre-reinforced posts, root and core failure for the titanium-alloy posts and core failure for the control group. The results suggest that post failures are more frequent in teeth restored with quartz fibre posts and root fractures are more frequent in teeth restored with titanium posts.

Bicuspid↗
PubMed1991

[Glass ionomer cement and "sandwich" restorations after two years of clinical service].

Esthetic restorations for class V lesions extending into root dentin often show marginal discoloration after some time. In this clinical study the long term quality of glass ionomer cement and "sandwich" restorations was compared with each other. In 19 patients 83 class V lesions with the apical margin in dentin were restored with glassionomer cement (I: Fuji II/G-C Dental; II: Ketac Fil/ESPE) or with a glass ionomer liner (III: Lining Cement/G-C Dental; IV: Ketac Bond/ESPE) and laminated with a composite. Where necessary the margins were prepared apically with a butt joint. The observation period between placement and last follow-up check varied between 18 and 44 months. Modified Ryge criteria were used for the clinical assessment of 77 restorations. Marginal quality was assessed in the SEM using replicas. 15.8% of the "sandwich" type and 5% of the glass ionomer cement restorations were lost. All restored teeth remained vital. Clinically the best marginal quality was found with a glass ionomer cement (II) whereas only two thirds of the sandwich restorations and the other glassionomer cement (I) had perfect margins. In the SEM the glassionomer cements had significantly less marginal openings than one of the sandwich restorations (III).

Composite Resins↗
PubMed1991

Fluoride release from glass ionomer cement in vivo and in vitro.

The aims of this study were to investigate in vivo the release of fluoride from three glass ionomer cements (GICs) Vitrebond, Ketac-Fil and ChemFil II into the saliva of preschool children for a 1-year period and also to study in vitro the release-absorption-release of fluoride from the same GICs for 16 weeks. In the first part of the study, glass ionomer restorations were placed in primary teeth in preschool children. Unstimulated saliva was collected and the fluoride in the saliva was measured before placement of the restorations, immediately after, after 3 weeks, after 6 weeks, and after 1 year. In the second part of the study, test specimens of GICs were placed in deionized water and the release of fluoride was measured weekly for 16 weeks. At week 12, samples were exposed to fluoride toothpaste. The concentration of fluoride in saliva was 0.04 ppm before placement of the restorations. After three weeks it had increased to 0.8 ppm and the level remained as high as 0.3 ppm even after 1 year. In the laboratory study the tested glass ionomer cements showed a capacity to absorb fluoride from the fluoride toothpaste and then release it. It is concluded that glass ionomer cement can act as a rechargeable slow release fluoride device.

Child↗
PubMed1991

Marginal leakage around V-shaped cavities restored with glass-ionomer cements: an in vitro study.

The object of this investigation was to assess the degree of marginal leakage around V-shaped cervical glass-ionomer cement restorations and compare it to that around composite resin restorations. Three different glass-ionomer cements and one composite resin control were assessed by means of dye penetration. Severe microleakage at the occlusal margins was found in 70% of the glass-ionomer cement restorations, but in only 10% of the composite resin restorations. A considerable amount of dye penetration was observed at the cervical margins of all restorations, including the controls. None of the glass-ionomer cements tested showed superiority in preventing marginal leakage occlusally or gingivally.

Bicuspid↗
PubMedDate not supplied

Resistance of occlusal fissures to demineralization after loss of glass ionomer sealants in vitro.

Seventy-one caries-free human occlusal fissures were used for this study. Twenty-two fissures were sealed with a glass ionomer sealant (Fuji Ionomer Type III--G-C Dental Industrial Corp., Tokyo, Japan), 24 were widened with a diamond bur and sealed with the glass ionomer sealant, and 25 were left unsealed. After one week, the sealants were removed as completely as possible with a probe. All fissures were demineralized for seven weeks. Sections made from the fissures were examined with a polarizing microscope, and the depths of the fissure lesions were measured. The mean lesion depths for controls, sealed natural fissures, and sealed widened fissures were 143, 93, and 75 microns, respectively. A statistically significant difference was noted between the two experimental groups and the control group (no sealant). The results suggest that fissures sealed with glass ionomer are more resistant to demineralization than control fissures, even after macroscopic sealant loss. This may be the result of the combined effect of fluoride released by glass ionomer and residual material in the bottom of the fissures.

Bicuspid↗
PubMed1990

[The utilization of glass ionomer sealing cements].

In order to fix the reconstructive work, a luting cement is used. The main task of this cement is to retain the restoration on the tooth and to fill and seal the gap between them. The first glass ionomer luting cement came on the market in 1978. In the beginning, the cement did not perform as expected: high solubility, high viscosity and hypersensitivity, even followed by pulp death, were reported. The glass ionomer luting cement compares now favourably with the traditional non-adhesive cements. Nevertheless, the zinc phosphate cement is still the most commonly used cementing agent in the dental private practice. Studies have shown that the problems of hypersensitivity after the use of glass ionomer luting cements are more dentist related than material related. This article explains how to use the glass ionomer luting cements in order to achieve a successful cementation.

Dental Restoration, Permanent↗
PubMed1990

Effect of water isolation and early finishing on hardness of glass ionomer cements.

Glass ionomer cements have the disadvantage of being vulnerable to moisture. We would like to overcome this problem by clinical procedures. Three glass ionomer cements were tested in vitro with the goal of protecting these materials from moisture during clinical operations. To observe the effectiveness of various surface protective measures, we divided each cement sample into six groups, each of which underwent 24-hour surface treatment. The first group was a control where the cement was covered with a glass slab for 24 hours. The remaining five groups were subjected to no treatment or treatment with varnish, cocoa butter, Teethmate-A, or Ketac-Glaze. Two additional groups were prepared for comparison of early finishing with and without water spray. When the Vickers hardness number (HVN) for each sample was measured at 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, and 40 days, it tended to increase after 24 hours, reaching a maximum value at different times with different cements. Analysis of variance revealed that during the first few days the hardness of the control was significantly different from that without treatment or with treatment by varnish or cocoa butter. However, treatment with Teethmate-A or Ketac-Glaze produced results close to those for the control. Significant differences in hardness during the first few days were noted when early finishing was carried out under wet and dry conditions. These findings indicate that a light-cured unfilled resin should be applied to the surface of glass ionomer cement immediately after the initial set to allow complete setting without interference by oral fluids. Also, water spray should be avoided during contouring of the cements if they have not fully hardened.

Glass Ionomer Cements↗
PubMed1990

[The border seal in restorations of class-V lesions with glass ionomer cement and composite (the sandwich filling)].

In 9 patients, 60 class V restorations were evaluated clinically and by scanning electron microscopy. All lesions were treated with glass-ionomer combined with composite resin. In 27 fillings (group A) the glass-ionomer lining cement was etched, whereas in 33 fillings (group B) the composite material was applied directly on the unetched glass-ionomer liner. Clinically, the retention of the fillings after one year was 100%. The margins of the fillings were checked with different explorers and found to be acceptable. Scanning electron microscopy of the margins of the fillings showed disappointing results. One week after placement of the fillings, only 16.2% (group A) and 7.4% (group B) of the cervical margins in dentin were rated perfect. After one year, even more cervical bond failures were observed. 9.7% perfect margins were found in group A, 3.2% in group B. Etching of the glass-ionomer liner had no influence on the cervical bond failure of the class V fillings.

Acid Etching, Dental↗
PubMed1990

Sorption of various drugs in polyvinyl chloride, glass, and polyethylene-lined infusion containers.

The sorption of chloroquine sulfate, diazepam, isosorbide dinitrate, lorazepam, midazolam, nitroglycerin, promethazine hydrochloride, thiopental sodium, and warfarin sodium to three types of containers was studied. Appropriate amounts of the drugs were added to 500 mL of 0.9% sodium chloride injection in polyvinyl chloride (PVC) bags, glass bottles, and Clear-Flex bags composed of a laminate of polyethylene, nylon, and polypropylene. The containers were stored in the dark at room temperature for 24 hours. Samples were taken at various intervals and assayed for drug concentration by high-performance liquid chromatography. There were no appreciable changes in pH after 24 hours, and all the admixtures remained clear and colorless. The potency of chloroquine sulfate, lorazepam, midazolam, promethazine hydrochloride, and thiopental sodium remained unchanged in glass, PVC, and Clear-Flex containers. Diazepam, isosorbide dinitrate, nitroglycerin, and warfarin sodium did not show any sorption to glass bottles and Clear-Flex bags. In PVC bags, however, up to 55% of diazepam, 23% of isosorbide dinitrate, 51% of nitroglycerin, and 24% of warfarin sodium was lost during the 24-hour study period. Diazepam, isosorbide dinitrate, nitroglycerin, and warfarin sodium in 0.9% sodium chloride injection showed a loss of potency when stored in PVC containers for 24 hours at room temperature, but none of the drugs studied lost potency when stored in glass bottles and Clear-Flex bags.

Adsorption↗