A 12-month clinical evaluation of a light-activated glass polyalkenoate (ionomer) cement for the direct bonding of orthodontic brackets

Glass polyalkenoate cements have the unique properties of physicochemically bonding to enamel and base metals and to leach fluoride over prolonged periods. These cements have been modified to provide a dual setting with both light activation and chemical cure to produce a more rapid set. This article reports a 12-month clinical trial of a light-activated glass polyalkenoate cement for the direct bonding of orthodontic brackets, compared with a standard composite bonding adhesive. There was no significant difference in failure rates of direct bonded orthodontic brackets cemented with Fuji II LC light-activated glass polyalkenoate cement (GC Industrial Co., Tokyo, Japan) (3.3%) compared with System I+ composite bonding resin (Ormco Corp., Glendora, Calif.) (1.6%).     

Accelerated evolution and molecular surface of venom phospholipase A2 enzymes

The objective of this study was to determine the in vitro shear bond strength (in megapascals) and location of bond failure with two light-cured glass ionomer resin systems. One system was a hybrid glass ionomer cement with resin (GC Orthodontics, Aslip, Ill), and the other system a glass-filled resin system (Reliance Orthodontic Products, Inc, Itasca, Ill). These systems, Fuji Ortho LC (GC Orthodontics) and Ultra Band Lok (Reliance), respectively, were compared to a light-cured composite resin. Maxillary premolar brackets (n = 200) were bonded to the facial surface of human premolar teeth. The two glass ionomer resin systems were each evaluated by two protocols, one according to the manufacturers' direction plus a variation of their respective technique. The five distinct groups (n = 40) were stored in 37 degreesC distilled water for 30 days and subjected to thermocycling before shear bond strength testing. The findings indicated that large variations existed between the bond strengths of the materials tested. The laboratory shear bond strength of the glass-filled resin glass ionomer cement (Reliance), whether tested in a dry or moist field, was similar to the composite control with all of the previous materials being significantly (P <.01) higher than both the hybrid glass ionomer cement groups (Fuji Ortho LC). However, the hybrid glass ionomer cement with enamel conditioner demonstrated a clinically acceptable mean megapascal value. The Adhesive Remnant Index values ranged from 0.53 to 1.62. The hybrid glass ionomer cement without enamel conditioning recorded the lowest mean adhesive remnant index score and the lowest mean megapascal score. Although both products are glass ionomer resin systems, their individual chemistries vary; this affects their clinical performance. Clinically, it may be suggested that glass ionomers used in a dry field may be beneficial for orthodontic bonding, and that glass ionomer resin systems used in a moist environment need an enamel conditioner.     

Psychiatric comorbidity among hospitalized AIDS patients vs. non-AIDS patients referred for psychiatric consultation

This study evaluated the clinical performance of a new resin modified glass ionomer cement, Geristore (Den-Mat Corp., Santa Maria, Calif.), for the bonding of orthodontic brackets and its effect on certain caries-associated microorganisms. This cement has been shown to possess increased mechanical properties and long-term fluoride release. There were 716 brackets bonded in 40 patients (17 males and 23 females), with a split-mouth technique and a composite resin, Phase II (Reliance, Itasca, III.), as a control. Bond failures were recorded up to 1 year. Plaque scores and plaque samples were taken from the area of the bonding adhesive in 20 patients, before, at 1 week, and 5 months after the placement of brackets. The plaque samples were investigated for the presence of Streptococcus mutans and lactobacilli. The overall bond failure rate was found to be 8.9% for Geristore and 3.1% for Phase II (p < 0.05). Labially, there was no significant difference (p > 0.05) in bond failure rate: 3.8% for Geristore and 1.7% for Phase II. The proportions of S. mutans and lactobacilli in plaque taken from around Geristore cement were reduced at 1 week and 5 months, when compared with Phase II resin, and this reduction was statistically significant (p < 0.05) at 1 week. Results of this study suggest that Geristore may be of use in the labial segments, especially in caries prone patients, in whom demineralization at debond may present an esthetic and restorative problem several years after treatment.     

Low-frequency ultrasound treatment of chronic venous leg ulcers in an outpatient therapy

An in vitro dye leakage study was performed to compare the sealing ability of glass ionomer, composite resin and glass ionomer/resin cement when used as restorative materials for G.V. Black class V cavities. In this research, standard Class V cavities were prepared in sound premolar teeth extracted for orthodontic reasons. The cavities were randomly divided into 3 groups. After filling the cavities with glass ionomer cement, composite resin and light curing glass ionomer/resin cement, the specimens were immersed in silver nitrate solution. Marginal microleakage at the interface between the cavity wall and restoration was evaluated. The results were analyzed by using Kruskal-Wallis and Mann Whitney U tests. Result of this in vitro study indicate that composite resin and glass ionomer/resin cement provide a better seal than glass ionomer cement.     

Variability in cytotoxicity and fluoride release of resin-modified glass-ionomer cements

New-generation glass-ionomer cements contain resin to improve their restorative properties. These resin-modified glass-ionomer cements vary considerably in their chemistry, which could result in corresponding variability in their physical and biological properties. This study investigated the cytotoxicity and the fluoride release of two resin-modified glass ionomers, a conventional glass-ionomer cement, and a resin composite. Samples were prepared and extracted in distilled water for 1, 4, and 7 days; eluates were filtered and tested by means of 3T3 mouse fibroblasts. Cytotoxicity (MTT assay) values were low for all materials and extraction times, indicating minimal cytotoxicity of all materials (less than 30% inhibition). Cytotoxicity of one resin-modified glass ionomer was significantly higher than for the other materials (p < 0.001). One resin-modified glass ionomer and the conventional glass-ionomer cement released significantly more fluoride at each time interval (p < 0.001) than the other resin-modified glass-ionomer cement and the resin composite. Fluoride release and cytotoxicity were correlated (r2 = 0.60; p < 0.001), although the fluoride release does not account for the cytotoxicity observed. Cytotoxicity and fluoride release suggest that one hybrid behaved more like a conventional glass ionomer, and the other like a resin composite. These differences may have implications for material selection in specific clinical situations.     

The effect of adhesive luting agent-dentinal surface interactions on compressive strength of two types of all-ceramic crowns

This research compared the compressive strength of two types of all-ceramic crown (Hi-Ceram and Duceram) as affected by selected luting cements (Zn phosphate, glass ionomer and composite resin cement). Thirty crowns of similar size and shape were constructed (15 crowns of each tested material) to fit a standard posterior tooth preparation. Five crowns from each material were cemented by one of the tested cements. The cemented crowns were loaded until catastrophic failure. A two-way analysis of variance was performed and showed that the type of utilized cement had a significant effect on the compressive strength being that Panevia Ex. resin cement the most effective one followed by glass ionomer and then finally zn phosphate cement. Statistical analysis also showed that Hi-Ceram crowns were more resistant to occlusal load than Duceram.     

Mycosis fungoides palmaris et plantaris or acral pagetoid reticulosis?

Direct bonding of brackets has become a routine procedure in clinical orthodontics. Many techniques and materials are currently advocated and used, the most recent being light-cured composites. Advantages of the light-cured systems are their relative ease of use, improved bracket placement, and more rapid set of the composite. For a new system to be clinically viable, it must possess properties that are at least as reliable as existing systems. The purpose of this longitudinal clinical study was to evaluate and compare the rate of success and/or failure between a visible light-cured bonding material (Sequence) and a chemically cured bonding material (System 1+), using both systems in every patient. Contralateral quadrants were bonded with each system respectively. A total of 32 patients were followed for a mean period of 11 months (range of 3 to 21 months), with a total of 531 brackets bonded, 265 with visible light-cured and 266 with chemically cured resins. Failures for each system were recorded and failure rates calculated. The failure rate of the visible light-cured composite was 11.3% and that of the chemically cured composite was 12%. A Chi-squared (chi2) test did not reveal any statistically significant differences between the failure rates of the two systems, (chi2 = 0.014, df-1, P > 0.9).     

Data from the National AIDS Behavioral Surveys. III. Multiple sexual partners among blacks in high-risk cities

According to the claims of the manufacturer, aethylcyanoacrylate can be used to bond orthodontic brackets and some orthodontists have already adopted its use for this purpose. Because, however, the use of the material as thus applied has not yet been the object of research, the question of its adhesion to tensile forces immediately after bonding and after 50, 100, and 150 days of placement in a physiologic saline solution (0.9% NaCl) is the subject of this study. 40 bovine upper incisors were extracted from 20 animals for each of the four points in time. The brackets were bonded with Cyano-Veneer and Mono-Lok according to a randomized list. Mono-Lok, an adhesive from the group of common orthodontic adhesives, functioned as the reference material. The bonding strength of the brackets in relation to the tensile forces was measured by means of a "Zwickuniversalprüfmaschine" (Zwick universal testing machine). Immediately after bonding, the cyanoacrylate demonstrated significantly higher bonding strength values than Mono-Lok. At 50, 100, and 150 days in the physiologic saline solution, the bonding strength of both materials showed no significant difference. It can thus be concluded that, when wires are employed immediately after bonding, the danger of bracket loss is significantly reduced through the use of cyanoacrylate.     

Outcomes of the surgical exposure, bonding and eruption of 82 impacted maxillary canines

BACKGROUND: Advances in bonding techniques and materials allow for reliable bracket placement on ectopically positioned teeth. This prospective study evaluates the outcome of forced orthodontic eruption of impacted canine teeth in both palatal and labial positions. METHODS: Eighty-two impacted maxillary canines in 54 patients were included in the study and were observed for 18 to 30 months after exposure. Following exposure by means of a palatal flap or an apically repositioned buccal flap, an orthodontic traction hook, with a ligation chain attached, was bonded to each impacted tooth using a light cured orthodontic resin cement. A periodontal dressing was placed over the surgical site for a period of time. RESULTS: All teeth were successfully erupted. Complications consisted of: failure of initial bond, at the time of surgery, which required rebonding; premature debonding at the time of pack removal and; debonding of brackets during orthodontic eruption. There was no infection, eruption failure, ankylosis, resorption or periodontal defect (pocket greater than 3 mm) associated with any of the exposed teeth. Attached gingiva of less than 3 mm was seen in only two of the buccally positioned canines (9%). CONCLUSION: Forced orthodontic eruption of impacted maxillary canines with a well bonded orthodontic traction hook and ligation chain, used in conjunction with a palatal flap or an apically repositioned labial flap, results in predictable orthodontic eruption with few complications.     

Initial tensile bond strength of resin-modified glass ionomers and polyacid-modified resins on perfused primary dentin

The objective of this study was to evaluate the initial tensile bond strength of a resin-modified glass ionomer (Photac-Fil) and two polyacid-modified composite resins (Compoglass, Dyract) to primary dentin. A hybrid composite resin (Tetric) and two chemical cured glass ionomers (BaseLine, Hi-Dense) served as controls. Ninety caries-free dentinal discs were ground flat and perfused with Ringer's solution. Dentinal surfaces were conditioned (except for Base Line). From each material, fifteen standardized specimens were attached to the dentin. Light-curing of the respective materials followed (1 min), and adhesion was tested with a universal testing machine 15 min after application. The highest initial bond strength was observed with Tetric (5.17 MPa). Closed test procedure (Kruskal-Wallis) showed significant differences between all materials (P < 0.05), except for Compoglass (1.82 MPa) vs. Dyract (2.35 MPa), and BaseLine (0.37 MPa) vs. Photac-Fil (0.42 MPa). The condensable glass ionomer Hi-Dense revealed a mean tensile bond strength of 0.79 MPa. Adhesion of (polyacid-modified) composite resins is superior to the other tested glass ionomer materials, when applied to perfused primary dentin.     

Effectiveness of chlorine dioxide in disinfection on two soft denture liners

OBJECTIVE: The purpose of this study was to evaluate a hydroxylapatite-based material and calcium sulfate when each was used under a resin-modified glass ionomer cement to repair furcation perforations. STUDY DESIGN: Perforations of pulp chamber floors were made in 72 teeth of 9 dogs. Perforations were divided into 3 equal-sized groups and repaired with resin-modified glass ionomer either alone or over an artificial floor. The artificial floor was either a hydroxylapatite-based material or calcium sulfate. Three dogs were killed at each of 3 intervals (1, 3, and 6 months). The tissue response to the tested materials was evaluated clinically, radiographically, and histologically. RESULTS: The hydroxylapatite-based material showed the highest radiographic success; this was followed by calcium sulfate and glass ionomer. From histologic evaluation, the average success rate was found to be 67% for calcium sulfate, 62% for the hydroxylapatite-based material, and 59% for glass ionomer. However, there was no statistical significant difference with the resin-modified glass ionomer when it was used alone and when it was used over a barrier. There was also no significant difference between the hydroxylapatite-based material and the calcium sulfate when they were used as artificial floors. CONCLUSION: The use of an artificial floor may not be necessary when flowable resin-modified glass ionomer cements are used.     

Prevalence and depth of artificial caries-like lesions adjacent to cavities prepared in roots and restored with a glass ionomer or a dentin-bonded composite material

One potential advantage of glass-ionomer materials for the treatment of root caries is their ability to release fluoride and so resist cariogenic attack. A commercially available composite material has also been reported to release fluoride which reduced caries lesions in the tooth tissue adjacent to it. The aim of this study was to assess the effectiveness of a conventional glass-ionomer restoration compared with a dentin-bonded, fluoride-releasing, composite restoration when exposed to a microbial artificial caries system. Artificial caries-like lesions produced in relation to the restorations were examined and classified either as outer (surface) lesions or as wall lesions. A split-unit experimental design allowed for within-tooth comparisons of the 2 experimental restorations at different sites on the root surface. These were either totally within the root surface or positioned at the amelo-cemental junction. Outer lesion depths were significantly (p < 0.001) shallower at all sites adjacent to the glass ionomer when compared with the composite restorations. Wall lesions were significantly (p < 0.01) more prevalent adjacent to the composite material. In addition, the cavity margin position significantly (p < 0.05) affected the incidence of wall lesions, particularly in the composite group. In conclusion, glass ionomer was successful in reducing the caries-like lesion production in the adjacent root surface. This resulted from improved marginal integrity and fluoride release from this material when compared with the composite bonding system used.     

Bonding of hybrid ionomers and resin cements to modified orthodontic band materials

Orthodontic bands often fail clinically at the band-cement interface. Hybrid ionomer and resin cements and a glass ionomer control were bonded to photo-etched and standard band materials, both of which were tested in as-received and air-abraded conditions. Cements were placed in a 3 mm diameter mold at the bonding interface and bonded to 6 x 6 mm stainless steel band specimens mounted to acrylic blocks. Specimens were stored in water for 24 hours at 37 degreesC and debonded in tension on a testing machine at 0.05 cm/minutes. Bond strengths (MPa) were calculated and data were analyzed by analysis of variance. Bond strengths to as-received bands were less than 3.4 MPa for cements tested, whereas bond strengths to air-abraded bands ranged from 7.1 to 17.7 MPa, except for the glass ionomer control. Air abrasion of band materials provides highly increased bond strength of hybrid ionomer and resin cements.     

Bond strengths of fluoride-releasing restorative materials

PURPOSE: To compare the shear bond strengths to dentin of four tooth-colored fluoride-releasing restorative materials that utilize different mechanisms of dentin-bonding. MATERIALS AND METHODS: Four materials were tested: a chemically-cured glass ionomer (Ketac-Fil); a light-cured resin-modified glass ionomer (Photac-Fil); a light-cured resin-modified glass ionomer in conjunction with a resin dentin-bonding agent (Vitremer); and a light-cured resin composite in conjunction with a resin dentin-bonding agent (Tetric). The enamel was removed from four sides of the twenty human noncarious extracted molars which had their roots embedded in acrylic blocks. Cylindrical samples of the materials were prepared in plastic molds and bonded to the dentin surface according to the manufacturers' instructions. After 24 hours of storage in a humidor, the samples were sheared with an Instron testing machine at a crosshead speed of 0.5 mm/minute. RESULTS: Statistical evaluation (ANOVA and Duncan's test) suggests that the fluoride-releasing resin composite material utilizing a resin dentin-bonding agent provided a significantly greater mean shear bond strength (16.5 MPa) after 24 hours storage than any of the selected glass ionomer materials. Of the three glass ionomer materials compared, the light-cured resin-modified material with a resin dentin-bonding agent provided a significantly greater mean shear bond strength (6.7 MPa) than the light-cured resin-modified material without a resin dentin-bonding agent (3.0 MPa) or the chemically-cured material (3.8 MPa).     

The effect of microetching on the bond strength of metal brackets when bonded to previously bonded teeth: an in vitro study

The purpose of this in vitro study was to answer the following questions for three different metal brackets: (1) when rebonding a previously bonded tooth, how do shear bond strengths compare for new brackets, new microetched brackets, and debonded microetcher cleaned brackets? and (2) how do the different bracket types compare with respect to the time required to remove composite resin from their bonding pads with a microetcher? Ninety human premolars and canines previously debonded of metal brackets were randomly assigned to 9 groups of 10 teeth each. New, new etched, and debonded etched cleaned brackets of each type were bonded with composite resin onto teeth, and the bonds tested to failure for shear bond strength. An analysis of variance and Duncan's multiple range test were used to compare bracket/enamel bond strength. Within each bracket type no significant differences were found between mean bond strengths for new, new etched, and debonded etched conditions, a finding that supports the use of microetching to clean accidentally debonded brackets. Mean times for removal of resin from bonding pads with a microetcher varied from 9.3 seconds to 11.9 seconds, with bracket (M) requiring significantly less time for removal of resin.     

Adhesive luting cements--classes, criteria, and usage

Clinical studies have shown that recurrent decay and lack of retention are the major causes of traditional crown and bridge failure. Optimal marginal accuracy and preparation retention form are important pre-requisites for longevity, as well as good patient oral hygiene. In an effort to provide improved clinical success, new classes of luting agents with improved physical properties and new therapeutic capabilities have been developed. Conventional glass ionomer cements provide fluoride release and adhesive properties. Recently introduced resin-modified glass ionomer luting materials add the potential for increased resistance to dissolution and improved physical and biological attributes. The resin luting cements are more difficult to use but provide greatly increased bonding capabilities and are necessary for strength requirements of all-ceramic restorations. This article describes the three classes of adhesive luting materials, provides a comparison of biological and physical properties, describes the indications and limitations of each class, and makes recommendations for clinical usage.     

Circadian rhythm of breath hydrogen in young women

PURPOSE: The retention forces of a newly developed compomer cement (Dyract Cem), a glass ionomer cement (Ketac Cem Aplicap), and a resin cement (F21) were examined. MATERIAL AND METHODS: Cemented cast gold crowns were removed along the path of insertion with a Zwick universal testing device. The impact of both a cured and a noncured additional bonding layer that were applied to the inner surface of the crowns was examined across the Dyract Cem group. RESULTS: The mean adhesive strength was measured at 2.36 +/- 0.69 N/mm2 in the Ketac Cem group, at 0.60 +/- 0.28 N/mm2 in the F21 group, and at 1.85 +/- 0.94 N/mm2 in the Dyract Cem group, respectively. The application of an additional bonding layer to the inner surface of the crowns did not significantly improve the retentive strength of Dyract Cem; the respective mean strengths were observed at 1.46 +/-0.33 N/mm2 for the uncured and at 1.70 +/- 0.76 N/mm2 for the cured bonding layers. CONCLUSIONS: Dyract Cem and Ketac Cem showed significantly higher retentive strengths than F21 (p < 0.001, Wilcoxon test, 5% level). No significant difference was found in bond strength between Ketac Cem and Dyract Cem.     

The effect of different reinforced glass ionomer restorative cement on vital tooth structure

The study was carried out on twenty-one contralateral pairs of caries free, premolars, that were indicated for extraction in conjunction with orthodontic treatment. The study was carried out on a Human male ranging in age from 12-22 y. Three different restorative reinforced glass ionomer cements were investigated two of them were commercial (chelon silver and legend silver) and experimental stainless-steel reinforced one. Three groups each formed of seven persons, the right side premolars used as control and the left side premolar received the investigated material. The experimental and its control tooth were extracted after four weeks of placement the filling materials. The enamel samples in the control and experimental teeth was obtained and prepared for x-ray diffraction analysis, then the teeth were prepared for histologic study. The x-ray diffraction analysis of the enamel samples revealed that, the intensity of fluorapatite was highest in the legend silver group, and the stainless-steel group was less than legend silver but higher than control and chelon silver specimens. Subsequently, the order of fluoride release was L > E > Ch & C. The histologic finding of this study showed that all the reinforced glass ionomer materials under investigation were non irritant to pulp tissue.     

Effect of peroxide bleaches on fluoride release of dental materials

PURPOSE: To investigate the effect of two bleaching agents, 35% hydrogen peroxide (Superoxal) and 10% carbamide peroxide (Opalescence), on the release of fluoride from Ketac-Fil, a glass ionomer cement, Photac-Fil, a glass ionomer/resin hybrid; and Tetric, a resin composite with fluoride. MATERIALS AND METHODS: Seven disks (9 x 3 mm) of each material were immersed in Superoxal for 1 hour to simulate an in-office application; seven other disks of each material were immersed in Opalescence 1 hour daily for 7 days to simulate a week of home bleaching regimen; and seven additional disks of each material without bleach served as a control. The disks were kept in deionized water and the water was tested for fluoride released every 24 hours for 14, 21, 28, and 35 days, respectively. RESULTS: Repeated measures ANOVA showed that the mean daily release of fluoride did not differ significantly (P > 0.05) between the bleaching agents or the control: Superoxal 6.17 ppm, Opalescence 6.45 ppm, and control 6.50 ppm. Statistically significant differences (P < 0.05) occurred for mean daily fluoride (+/- standard error) released from the three materials over the 35-day period: Photac-Fil 12.31 +/- 0.48 ppm > Ketac-Fil 7.07 +/- 0.66 ppm > Tetric 0.12 +/- 0.01 ppm, respectively.