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PubMed1998

Residual monomer/additive release and variability in cytotoxicity of light-curing glass-ionomer cements and compomers.

In previous studies, light-cured glass-ionomer cements have been shown to evoke cytotoxic reactions. It was the purpose of this investigation (a) to determine the nature of the ingredients released into an aqueous medium from 2 light-cured glass-ionomer cements (GICs) and 3 compomers; (b) to evaluate the cytotoxicity of these extracts; and (c) to correlate the extent of the cytotoxic effects with eluted substances. Specimens of 2 light-cured GICs and 3 compomers were prepared and extracted in distilled water or cell culture medium for 24 hrs (surface-liquid ratio 42.4 mm2/mL). The aqueous eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). The relative amounts of the components released from various products were compared by means of an internal caffeine standard [%CF]. For evaluation of cytotoxic effects, permanent 3T3 fibroblasts were incubated with medium extracts for 24 hrs. In addition, the ED50 concentration of the photoinitiator diphenyliodoniumchloride (DPICl) was determined. In all extracts, several water-elutable organic substances were found: (Co)monomers (especially HEMA and ethylene glycol compounds), additives (e.g., camphorquinone and diphenyliodoniumchloride), and decomposition products. The extracts of 3 products inhibited cell growth only moderately, whereas the light-cured GIC Vitrebond and the compomer Dyract Cem revealed severe cytotoxic effects. Vitrebond liberated the initiator DPICl, whereas Dyract Cem segregated a relatively high quantity [2966 %CF] of the comonomer TEGDMA in comparison with the other products. The present data show that TEGDMA and DPICl may be regarded as the prime causes for cytotoxic reactions evoked by the investigated light-cured glass-ionomer cements or compomers. Therefore, leaching of these substances should be minimized or prevented.

3T3 Cells↗
PubMed1998

Flexural properties and swelling after storage in water of polyacid-modified composite resin (compomer).

The flexural properties, flexural strength, flexural modulus and modulus of resilience, of four commercially available compomers, and one resin-modified glass ionomer cement and one microfilled resin comosite (as controls) immediately after light-activation and after 1 week of water storage were tested to assess the mechanical properties. The water swelling after storage in water was also tested to assess the characteristics in water of compomers. The flexural test showed compomers to be statistically stronger and more resilient than the resin-modified glass ionomer cement or the microfilled composite, when tested immediately after light-activation and after 1 week of water storage. Water swelling of compomers was statistically less than the resin-modified glass ionomer cement after 1 week of water storage.

Analysis of Variance↗
PubMed2002

Influence of 30% hydrogen peroxide bleaching on compomers in their surface modifications and thermal expansion.

The surface modifications and the coefficient of thermal expansion of compomers after treatment with a 30% hydrogen peroxide bleaching agent were investigated. Three compomers (Compoglass F, Elan and F2000) were nonbleached and bleached for 1 and 3 days. The surface modification and the coefficient of thermal expansion of each bleached compomer were evaluated using a scanning electron microscope and a thermomechanical analyzer, respectively. As a result, Compoglass F and Elan showed slight surface degradation, whereas F2000 showed many cracks on its surface and these cracks were not observed in Compoglass F and Elan. Bleached Elan and F2000 has changed to the extent where their the coefficient of thermal expansion increased compared with those of nonbleached specimens. In addition, bleached compomers showed a strong inverse correlation between the coefficient of thermal expansion and the volume percent of filler.

Analysis of Variance↗
PubMed1999

Solubility and fluoride release in ionomers and compomers.

OBJECTIVE: The degree of solubility and the fluoride release of glass-ionomer cements and "compomers" were determined as a function of time. METHOD AND MATERIALS: Three conventional glass-ionomer cements, three hybrid ionomers, and two compomers were included in the study. Disk-shaped specimens were prepared and immersed in a lactic acid solution. Solubility was evaluated from determinations of loss of mass as a function of time. To evaluate fluoride release, similar specimens were immersed in 50 mL of deionized water to which 50 mL of buffer solution was added. A fluoride ion detector was used to read the concentration of fluoride ion in the overall solution at different times after immersion. RESULTS: Material and time factors had a significant influence on results. The compomers showed less corrosion and fluoride release than the ionomers. Some correlation was found between solubility and fluoride leakage values. CONCLUSION: Components of both the ionomers and compomers that were studied can dissolve in water. The materials leak fluoride ions in amounts that differ according to the characteristics of the individual products.

Analysis of Variance↗
PubMed2002

Laboratory strength of glass ionomer cement, compomers, and resin composites.

PURPOSE: The study evaluates the compressive, flexural, and diametral tensile strengths of 8 core build-up materials from different material classes (highly viscous glass ionomer cement, autocured resin composite, and compomers). MATERIALS AND METHODS: All materials were manipulated according to the manufacturers' recommendations for use as core materials. At a temperature of 23.0 +/- 1.0 degrees C the properties of compressive, diametral tensile and flexural strength were determined using a universal testing machine at 15 minutes, 1 hour, and 24 hours after material preparation. Using one-way analysis of variance (ANOVA), multiple mean value comparisons were performed to determine significant differences (p< or =.05) between the core restoration materials. RESULTS: The values for compressive strength varied from 40.3 +/- 5.2 MPa (compomer) to 237.4 +/- 37.3 MPa (autocured resin composite) for the 3 measurement times. At 15 minutes, 1 hour, and 24 hours after first mixing, the ANOVA showed significant differences (p < or =.05) between the resin composite Core Paste and all of the other materials. Diametral tensile strengths ranged from 5.5 +/- 1.1 MPa for glass ionomer cement to 39.1 +/- 2.9 MPa for composite core material. Three-point flexural strength showed values ranging from 12.1 +/- 2.5 MPa for glass ionomer cement to 92.1 +/- 9.7 MPa for compomer between the 3 measurement times. CONCLUSIONS: Setting time influences the mechanical properties of the materials tested in this study. Autopolymerizing resin composite Core Paste demonstrated greater compressive and flexural strengths at the 3 measurement times than the other materials tested. Reinforced composites, in comparison to the autocured resin composites, yielded no improvement in tensile strength. Flexural and tensile strengths of the glass ionomer cement were lower than those of autocured resin composites and compomers.

Analysis of Variance↗
PubMedDate not supplied

Marginal and internal adaptation of stratified compomer-composite Class II restorations.

Different approaches have been proposed to improve the adaptation of Class II restorations, including applying low-elasticity modulus base liners. This in vitro fatigue test (or study) evaluated the influence of the compomer base-lining configuration on restoration adaptation. Direct Class II MOD box-shaped composite restorations with or without base and lining (n=3x8) were placed on intact human third molars with proximal margins 1 mm above or under the CEJ. The compomer (Dyract) was applied as a 1 mm-thick lining or as a base, closing proximo-gingival margins. Marginal adaptation was assessed before and after each phase of mechanical loading (250,000 cycles at 50N, 250,000 cycles at 75N and 500,000 cycles at 100N); internal adaptation was evaluated after test completion. Gold-sputtered resin replicas were observed in the SEM and restoration quality evaluated in percentages of continuity (C) at the margins and within the internal interface after sample section. Mechanical loading did not influence adaptation to enamel, while it adversely affected restoration adaptation to dentin for the full composite and compomer-base restorations (C varied, respectively, from 95.2 to 75.3% and from 98.0 to 10.6%). The internal adaptation quality showed the same general trend, however, with reduced scores of continuity. In this experimental condition, application of a low elasticity modulus layer under the restorative material proved advantageous but the compomer should not contact the gingival margins.

Bisphenol A-Glycidyl Methacrylate↗
PubMed2003

The marginal seal of a flowable composite, an injectable resin modified glass ionomer and a compomer in primary molars--an in vitro study.

The present study was carried out to compare the marginal microleakage of some newer materials viz. a flowable composite, an injectable resin modified glass-ionomer and a compomer in Class I cavities of 30 non carious primary molars. After 0.5% basic fuchsin dye penetration and sectioning, the teeth were studied under stereomicroscope. The results obtained revealed that flowable composite showed significantly lower microleakage (p<0.05) as compared to injectable resin-modified glass ionomer and compomer. However, no significant difference was observed when injectable resin modified glass-ionomer cement was compared to compomer. This concludes that flowable composite materials adhere better to the primary teeth than resin modified glass ionomer and compomer.

Adhesiveness↗
PubMed2003

Comparison of shear bond strength of composite, compomer and resin modified glass ionomer in primary and permanent teeth: an in vitro study.

The aim of this study was to determine the difference in shear bond strength between Composite, Compomer and Resin modified glass ionomer cement in primary and permanent teeth. Thirty extracted primary molars and thirty premolars were selected and buccal surfaces of all the teeth were made smooth with the help of 300 grit silicon carbide paper. These specimens were then divided into 6 groups. Restorative materials were placed on the buccal surfaces of respective specimens with the help of acrylic template. All the specimens were subjected to thermocycling and shear bond strength was tested under the Honsfield testing machine and results were recorded in megapascals (MPa). The resultant scores were tabulated and statistically analysed. It was observed that in case of primary teeth resin modified glass ionomer exhibited significantly higher shear bond strength as compared to composite and compomer, where as on permanent teeth composite demonstrated a significantly higher shear bond strength than that of the resin modified glass ionomer and compomer, where as compomer gave poor shear bond strength in both primary and permanent teeth.

Bicuspid↗
PubMedDate not supplied

Microleakage and marginal hybrid layer formation of compomer restorations.

The tested hypotheses of this study were that dentin enamel bonding agents (DBAs) proposed for compomers create a hybrid layer (HL) that seals the margins of Class V restorations and HL is free from voids or gaps on both enamel and dentin margins. For purposes of this study, Class V restorations (n = 70) were made in vitro at the CEJ in extracted third molars. Different systems (bonding agent + compomer) were selected. After finishing with discs, each margin was polished with diamond polishing paste for one minute, treated with a 2.5% NaOCl gel for 10 seconds and washed with deionized water to remove polishing debris and non-infiltrated collagen. All restorations were immersed in dye solution for 24 hours, then inspected along the margins. SEM analysis was used to evaluate the morphology of the marginal HL and microleakage tests to evaluate their ability to seal the margins of restorations. Marginal leakage was observed along the dentin and enamel margin. A thin marginal HL (0.5-1.2 microm) was detected only along the dentin margin of several bonding systems but not along the enamel margin. Porosities and gaps were detected along margins when no HL was observed. The results demonstrated that the tested bonding agents for compomers produced a thin marginal hybrid layer, especially along the dentin margin. Microleakage had a relationship with the morphology (gap, porosities and thickness) of this hybrid smear layer. In conclusion, the DBAs tested specifically developed for compomers did not ensure an intimate interfacial adaptation, because microleakage was detected along the enamel and dentin interfaces and the marginal hybrid layer was only partially homogeneous.

Adult↗
PubMedDate not supplied

Effects of different preparation techniques on the microleakage of compomer and resin fissure sealants.

PURPOSE: The aim of this study was to compare the microleakage of a compomer and resin sealant in vitro using different surface preparation techniques. METHODS: Microleakage of a compomer (Dyract Seal, DeTrey) and a resin sealant (Helioseal F, Vivadent) was investigated on 125 intact third molars. Materials and the surface preparation techniques were: Group 1--phosphoric acid (37%)+Helioseal F; Group 2--AlO2 air abrasion+Helioseal F; Group 3--nonrinse conditioner (NRC)+Prime&Bond+Dyract Seal; Group 4--phosphoric acid+Dyract Seal; Group 5--AlO2 air abrasion+Dyract Seal. RESULTS: Pretreatment with phosphoric acid produced the lowest microleakage scores when applied with compomer and resin fissure sealants and there was no statistical difference (P>.05). CONCLUSIONS: Compomer sealant used with a nonrinse conditioner (NRC) was not as successful as pretreatment with phosphoric acid etching, whereas AlO2 air abrasion pretreatment was ineffective in preventing microleakage in both sealants.

Acid Etching, Dental↗
PubMed1997

Surface hardness and wear of glass ionomers and compomers.

PURPOSE: To determine the surface hardness and in vitro wear of glass ionomer cements (GIC) and compomers in comparison with a resin composite and to test for a possible correlation between the determined hardness and wear values. MATERIALS AND METHODS: Samples were made of conventional GIC (Ketac-Fil, Fuji II, Fuji IX, Ketac-Prototype = Ketac-Molar), resin-modified GIC (Photac-Fil, Fuji II LC, Vitremer), compomers (Dyract, Compoglass) and resin composite (Z100) for the hardness test (n = 10) and for the wear test (n = 3). The materials were handled according to the manufacturers' instructions. The samples were stored in deionized water for 48 hours at 37 degrees C prior to the determination of Rockwell hardness and three-body in vitro wear. RESULTS: Hardness could not be measured on Ketac-Fil and Fuji II as the samples fractured before a reading was obtainable. Statistically significant differences were found in hardness and wear between brands and between the four types of material. Surface hardness: resin-modified GIC < conventional GIC = compomers < resin composite. In vitro wear: resin-modified GIC > compomers > conventional GIC > resin composite. A negative correlation between hardness and wear was recorded.

Analysis of Variance↗
PubMed1996

Compomers and glass ionomers: bond strength to dentin and mechanical properties.

PURPOSE: To compare compomers and conventional and resin-modified glass ionomer cements (GIC) with respect to bond strength to dentin and mechanical properties. MATERIALS AND METHODS: Seven conventional GICs (BaseLine, ChemFil Superior, Fuji II, Fuji IX, Ketac-Fil, Ketac-Silver, and Miracle Mix), three resin-modified GICs (Fuji II LC, Photac-Fil, and Vitremer), and two compomers (Dyract and Compoglass) were investigated. Bond strength was determined to untreated as well as pre-treated human dentin. The mechanical properties tested were flexural strength and flexural modulus. RESULTS: Mean bond strengths to untreated dentin ranged from 0.0 MPa (Photac-Fil) to 8.5 MPa (Fuji IX). Generally, the bond strengths of the compomers and resin-modified GICs were lower than those of the conventional GICs. Mean bond strengths to pre-treated dentin ranged from 0.5 MPa (Photac-Fil) to 13.7 MPa (Compoglass). No clear-cut bond strength pattern was observed for the three types of materials. Pretreatment improved the bond strength of nine out of 12 materials. Flexural strengths ranged from 13 MPa (Miracle Mix) to 180 MPa (Dyract). Generally, the compomers were stronger than the resin-modified GICs, which were much stronger than the conventional GICs. Flexural moduli ranged from 4.0 GPa (Miracle Mix) to 7.2 GPa (Fuji IX and Dyract) with no typical variations between the three categories of materials.

Analysis of Variance↗
PubMed1998

Retention and marginal adaptation of a compomer placed in non-stress-bearing areas used with the total-etch technique: a 3-year retrospective study.

The aim of this clinical study was to evaluate class V and class III cavities restored with a polyacid-modified resin composite (compomer) restorative material in association with two different dentin-enamel bonding systems: Dyract-PSA (Primer Sealer Adhesive-DentSply, Germany) and Prime & Bond 2.0 (DentSply, Germany). The control group was a hybrid composite used with ProBond bonding system (DentSply, Germany). A total of 116 restorations (79 class V, 37 class III) were made and reevaluated after 1, 2 and 3 years in 55 patients in two private practices and in a university department. Class V nonretentive cavities were located at the CEJ level and class III at interproximal level close to CEJ. Each cavity was prepared using a water-cooled, high-speed handpiece with a fine diamond burr. A small bevel was prepared along enamel margin. Cavity dimensions were no more than 3.5 x 3.5 mm (using burr as reference point). Each restoration was finished immediately with fine diamond burrs and Sof-Lex disks (3 M, USA). The criteria that were evaluated by the USPHS method included: retention, color match, marginal integrity, marginal discoloration, and secondary caries. Results indicated that all compomer restorations were fully retained at 3 years, and that no secondary caries detected. Seven composite restorations were lost during the 3-year study. No statistical differences were observed between class III and class V or among other conditions (e.g., upper-lower arc, sex, age). This study demonstrates that compomers are suitable restorative materials for class III-V restorations. They may represent a clinical alternative to composites in class V and III restorations.

Adult↗
PubMed1999

Bond strength of a compomer to dentin under various surface conditions.

This study determined the influence of different dentin pretreatments on the shear bond strength of an adhesive system and corresponding compomer material. One hundred and twenty freshly extracted human molars were ground with wet SiC paper to expose flat oral/buccal surfaces of superficial dentin. The teeth were assigned to 12 treatment groups (n = 10) based on dentin surface finish (600-grit SiC vs. air abrasion vs. 40 microns diamond bur), surface conditioning (acid etching vs. no etching), and moisture content of the dentin (moist vs. dry). Cylinders of Compoglass F compomer were bonded to the dentin with Syntac Single-Component. After 24-h storage in distilled water, the specimens were debonded in shear mode. Bond strengths in MPa (SD) were calculated and bonding sites were analyzed for the mode of failure. Three-way ANOVA revealed significantly higher bond strength values for acid etched specimens (P = 0.001). Moisture content of the dentin surface (P = 0.614) and mechanical surface finish (P = 0.367) had no significant influence on the results. Debonding in unetched groups ranged from 94 to 100% adhesively. Acid etched groups showed adhesive failures ranging from 56 to 100%. To obtain a more reliable bond it is recommended that dentin is acid etched prior to the bonding of a compomer.

Acid Etching, Dental↗
PubMed2005

A triclosan-containing compomer reduces Lactobacillus spp. predominant in advanced carious lesions.

OBJECTIVES: To assess the antimicrobial effect of acid etching or a triclosan-containing compomer on the cultivable microflora of incompletely excavated dentinal carious lesions. METHODS: Thirty detinal lesions were opened with a diamond burr. Subsequent to removal of the softened biomass a sample of dentin was taken from the cavity floor with a round bur. Ten cavities each were treated with 36% phosphoric acid (PH) for 15s, covered with a triclosan-containing compomer (TC) or received no treatment as control (CO). All lesions were restored with a compomer composite. Sampling was performed directly after etching in the PH group and at re-entry after 6 weeks in all groups. Aliquots were plated on blood agar and selective media for Lactobacilli (Rogosa) and mutans Streptococci (MSB). Cultures were incubated anaerobically for 7 days at 37 degrees C prior to quantitative assessment and biotyping of the isolates. RESULTS: Application of phosphoric acid resulted in initial reduction of the totally cultivable microflora (p=0.006). Evaluation of the total number of cultivable microflora after 6 weeks revealed no differences between the groups (p>0.05). Lactobacilli counts were significantly lower in the TC group compared to the PH and CO groups (p<0.05). No difference was detected between the PH and CO groups after 6 weeks. SIGNIFICANCE: Phosphoric acid initially reduces the number of microorganisms in carious dentin but not in the longer term. The experimental triclosan composite suppresses Lactobacilli species over a period of 6 weeks.

Acid Etching, Dental↗
PubMed1998

Sealing ability of two "compomers" applied with and without phosphoric acid treatment for Class V restorations in vivo.

STATEMENT OF PROBLEM: "Compomers" are being used with increasing frequency in Europe and North America. PURPOSE: This study evaluated the marginal seal of two compomers in vivo. MATERIAL AND METHODS: Periodontally involved teeth, scheduled for extraction, were selected. Four groups of a combination of materials were used (Dyract with Dyract-PSA primer, group 1; Dyract with Prime and Bond 2.0, group 2; Compoglass with SCA primer, group 3; and Compoglass with Syntac Single Component, group 4). The restorations were made in a standardized shaped cavity, across the cementoenamel junction, and the teeth were extracted after 2 to 3 months of clinical service. The specimens were kept in a solution of 2% methylene blue for 24 hours. After being embedded in epoxy resin, sections were made with a low speed saw along the longitudinal axis of the teeth. The examination of dye penetration was made with a microscope at a magnification of x20 and scoring was done at both coronal and apical sites. Kruskal-Wallis statistical analysis was performed at 5% significance level. RESULTS: Groups 2 and 4 scored significantly less than groups 1 and 3 and for groups 2 and 4, 30% of the restorations exhibited leakage. CONCLUSION: These restoration systems did not completely prevent leakage either at the incisal or the cervical margins. Therefore the use of an enamel-dentin bonding system in combination with the proprietary compomer is recommended.

Acid Etching, Dental↗
PubMed1998

Microleakage of Class V compomer and light-cured glass ionomer restorations.

STATEMENT OF PROBLEM: Resin-modified (light-cured) glass ionomer and polyacid-modified composite resin (compomer) restorations are popular choices for the restoration of root caries and cervical abrasion/erosion lesions, but clinical studies are relatively few and have been published primarily as abstracts. PURPOSE: In the absence of adequate clinical data, the marginal integrity of restorations of the above two types of material was compared in vitro. The microleakage of restorations of two light-cured glass ionomer restorative materials and of one compomer material was evaluated. METHODS AND MATERIAL: Restorations of the three materials were placed in facial and lingual Class V cavity preparations in bovine incisors. All preparations were centered on the cementoenamel junction and were prepared with 45-degree enamel bevels. After thermal cycling, teeth were immersed in methylene blue dye, then sections of the restorations (n = 16) were visually evaluated. RESULTS: Dye penetration was observed at approximately 20% of restoration margins for all three materials, with the greatest incidence of severe leakage in the compomer restorations. CONCLUSION: No significant difference in microleakage among the three materials (ANOVA; p > 0.05) was found.

Animals↗
PubMed1999

The ultrastructure of a compomer adhesive interface in enamel and dentin, and its marginal adaptation under dentinal fluid as compared to that of a composite.

OBJECTIVES: To visualise the ultrastructure of the interface of SCA compomer adhesive and of Optibond composite adhesive in enamel and dentin, and to relate the findings to the marginal adaptation of these two products in mixed class V restorations. METHODS: The ultrastructure was investigated using a scanning electron microscope (SEM) with and without prior argon ion etching, an environmental SEM, a field emission SEM, a confocal laser scanning microscope, and a transmission electron microscope. The marginal adaptation was quantified in mixed class V restorations by using the replica technique and a SEM under simulated dentinal fluid before and after simultaneous mechanical and thermal loading. RESULTS: The ultrastructure of the compomer adhesive interface differed from those of the composite. However, no significant difference was discerned as regards the percentage of "continuous margin" in the enamel marginal area before loading, and in the dentin area before and after loading (p < 0.05; unpaired t-test). Only after loading, the percentage of "continuous margin" in enamel was significantly (p < 0.05; unpaired t-test) better than that of the compomer. SIGNIFICANCE: The results indicated that the ultrastructure of the adhesive interface allowed no clear conclusions to be drawn as to the quality of marginal adaptation.

Compomers↗