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PubMed2001

Evaluation of nonrinse conditioning solution and a compomer as an alternative method of bonding orthodontic bracket.

Damage to the enamel surface during bonding and debonding of orthodontic brackets is a clinical concern. Alternative bonding methods that minimize enamel surface damage while maintaining a clinically useful bond strength are an aim of current research. The purpose of this study was to compare the effects of using two enamel conditioners and adhesives on the shear bond strength and bracket failure location. Forty freshly extracted human molars were pumiced and randomly divided into two groups of 20 teeth. Metal orthodontic brackets were bonded to the enamel surface by one of two protocols: 37% phosphoric acid with a composite adhesive (Transbond XT) or a nonrinse conditioner with a compomer adhesive (Dyract flow). The teeth were mounted in phenolic rings and stored in deionized water at 37 degrees C for 24 hours. A Zwick Universal Testing Machine was used to determine shear bond strengths in MegaPascals. The residual adhesive on the enamel surface was evaluated using the Adhesive Remnant Index. Student t-test and chi2-test were used to compare the two groups. Significance was predetermined at P < or = .05. The results of the t-tests indicated that there were significant differences between the two adhesive systems (t = 11.18 and P = .001) with the nonrinse conditioner/compomer system having lower shear bond strength (X = 1.7 +/- 0.9 MPa) than the phosphoric acid/composite adhesive (X = 10.4 +/- 2.8 MPa). The results of the Chi Square test evaluating the residual adhesives on the enamel surfaces also revealed significant differences between the two groups (chi2 = 7.62, P = .022). In conclusion, a nonrinse conditioner used with a compomer adhesive had significantly lower shear bond strength than a phosphoric acid/composite adhesive system.

Acid Etching, Dental↗
PubMed1998

Bond strength and interfacial micromorphology of compomers in primary and permanent teeth.

OBJECTIVES: To (1) test and compare the shear bond strength of compomers (Compoglass, Dyract, Hytac) to primary and permanent dentin, (2) compare the values to those obtained with a resin-modified glass ionomer (Vitremer), and (3) evaluate the material-dentin interfacial morphology. SAMPLE AND METHODS: The facial and lingual surfaces of 32 primary and 32 permanent teeth were used. The manufacturers' instructions were followed for the bonding procedures. After bonding, the teeth were thermocycled and sheared. RESULTS: ANOVA and Student-Newman-Keuls test revealed that the shear bond strength for Dyract was significantly higher than for the other restorative systems tested, both for primary (P < 0.001) and permanent (P < 0.01) teeth. Compoglass bond strength was significantly lower than Vitremer for the primary teeth dentin (P < 0.01). The shear bond strength for Compoglass to permanent dentin was significantly lower than for all other restorative systems (P < 0.001). There was a significantly higher shear bond strength for Compoglass (P < 0.05) and Dyract (P < 0.01) restorative systems for primary compared to permanent teeth. For all products tested, all samples revealed cohesive failures. The highest frequency of cohesive failure was reported with Compoglass in both primary and permanent teeth and for Hytac and Vitremer in permanent teeth. Micromorphologically, all restorative systems revealed good adaptation to the underlying dentin; however, there was no evidence of the formation of a hybrid layer or deep resin penetration inside the dentinal tubules. There was no difference in the interfacial morphological adaptation between the primary and permanent teeth. CONCLUSIONS: The compomers tested had shear bond strength values between those of resin-modified glass ionomers and resin composites.

Analysis of Variance↗
PubMed2003

Analysis of surface roughness of glass-ionomer cements and compomer.

The purpose of this study was to evaluate the surface roughness of two glass-ionomer cements (Vitremer and Chelon-Fil), and one compomer (Dyract) when submitted to different finishing/polishing procedures at different times. A hundred 80-sample discs were made of each material and randomly divided into six finishing/polishing groups: mylar strip (control); Sof-Lex discs; diamond burs; diamond burs/Sof-Lex discs; 30-fluted carbide bur; 30-fluted carbide bur/Sof-Lex discs. These procedures were carried out immediately after preparation of the samples, after 24 and 168 h. Average surface roughness (Ra) was measured with a profilometer and the values were compared using anova (P < 0.05). The smoothest surface for all materials was obtained when cured in contact with the mylar strip. All other tested products increased surface roughness of restorative materials, but Sof-lex discs lead to better results. The worst results were verified with diamond burs. The finishing/polishing procedures, when performed immediately, can improve the roughness of glass-ionomer cements but not of the compomer tested.

Analysis of Variance↗
PubMed2000

Changes in the mechanical properties and surface texture of compomer immersed in various media.

STATEMENT OF PROBLEM: Limited information is available about the mechanical behavior of compomer under intraoral conditions. PURPOSE: This in vitro study evaluated changes in the mechanical properties and surface texture of compomer and other materials, used in similar clinical circumstances, when immersed in various media. MATERIAL AND METHODS: Hardness measurement for 5 tested materials and 4 immersion media was obtained with a Vickers hardness testing machine. Compressive strength was measured using an Autograph at a crosshead speed of 0.75 mm/min. All readings were taken for up to a 60-day period. An electron probe microanalyzer was used to give an SEM image. RESULTS: The average compressive strength and Vickers surface hardness showed a significant difference between materials. Results showed an overall increase in the solubility of specimens immersed in low pH soft drinks. CONCLUSION: There was a difference in the mechanical properties and surface texture of the materials tested in this study when they were immersed in various media.

Alcoholic Beverages↗
PubMed1999

Cytotoxic effects of extracts of compomers.

We have studied the cytotoxicity of 10 commercially available compomers. Extracts were taken in cell culture medium of non-cured, freshly-cured, and aged samples. Murine L-929 fibroblasts were exposed to the extracts for 24 h and the cytotoxicity was evaluated using dimethylthiazol diphenyltetrazolium (MTT) assay and neutral red uptake (NRU). Extracts were rated as severely, moderately, or slightly cytotoxic when the activity relative to controls was less than 30%, between 30% and 60%, or greater than 60%, respectively. Extracts of non-cured materials were rated severely toxic with both methods, with one exception. All but one freshly-cured material exhibited moderate to severe toxicity in both assays. Aged test specimens were rated moderately to severely toxic. Non-cured materials were generally more toxic than cured, with two exceptions. Aging and polishing the samples to remove non-polymerized surface film affected cytotoxicity to a varying degree. Curing reduced cytotoxicity in the MTT test from severe to moderate in 7 of 9 materials, but had relatively little effect in the NRU assay. Aging and polishing, however, had little effect on cytotoxicity evaluated by the MTT test, but markedly reduced cytotoxicity in NRU in 6 of 8 extracts. To conclude, extracts made from compomers used for dental fillings were found to be cytotoxic both before and after setting.

Analysis of Variance↗
PubMed2004

The release of ions by compomers under neutral and acidic conditions.

Three commercial compomers have been studied for their interaction with aqueous solutions (i.e. water at pH 5.9 and lactic acid at pH 2.7). Light-cured discs of these materials (12.8 diameter x 1 mm depth; Dyract AP, Compoglass F and F2000) were prepared and stored in 5 cm(3) of either water or lactic acid at pH 2.7. After 1 week, mass changes, pH changes and ion-release were determined. For the specimens stored in water, the effect of maturation under neutral conditions was studied by continuing storage for 3 months, followed by storage in lactic acid for a further week after which ion release and pH change were determined. Student's t-test was used to determine statistical significance of any changes observed. All three cured compomers absorbed water and altered the pH of the solutions, though this was statistically significant only in lactic acid. They were found to release Na, Ca, Sr, Al, Si, P and F ions, with greater amounts being released in acidic conditions than neutral ones. More fluoride was released in acid than in water, but the proportion of free (uncomplexed) fluoride to bound (complexed) fluoride was much lower than in neutral conditions. This was attributed to the formation of strong complexes with aluminium. Maturing specimens for 3 months made very little difference to their interaction with the acid solution, except for the total release of fluoride, which was some two to three greater than from the immature specimens.

Absorption↗
PubMed2005

Effect of APF gel on micromorphology of resin modified glass-ionomer cements and flowable compomers.

The purpose of this study was to evaluate the surface micromorphology of resin modified glass-ionomer cements and flowable compomers. In the study two resin modified glass-ionomers and two flowable compomers were used to prepare standardized 20 cylinderic samples. Samples were divided into four groups. Surface treatments with APF gel for experimental groups (group B,C,D) or distilled water as a control (group A) were performed four times. In group B, only APF gel was applied. In group C, after the APF gel application, the samples were immersed into the demineralizing and remineralizing solutions. In group D, before the APF gel application, the buffer solution was applied. The examinations of the surface micromorphology of the materials were made by using scanning electron microscope (SEM). Results showed that in group B all of the materials except Compoglass Flow, and in group C all of the materials showed erratic behaviours. In group D, severe erratic effect (score 2) was obtained on the surfaces of Vivaglassliner and Dyract Flow, and for the others score 1 signals were found. The moderate degradation was obtained by applying of only APF gel on the surfaces of both material groups. The addition of pH circulation caused increasing of micromorphologic changes on the surfaces of all materials. The effect of application of buffer solution on the surfaces before APF gel changed according to the materials. If acidulated fluoride gel is preferred for prophylactic therapy in patients' mouth, for the success, either buffer or neutral fluoride have to be applied on the restored teeth by resin based materials before acidulated fluoride application.

Acidulated Phosphate Fluoride↗
PubMed2004

Class II restorations in primary teeth: 7-year study on three resin-modified glass ionomer cements and a compomer.

The aim of this randomized study was to compare the longevity and cariostatic effects of 1565 class II restorations in primary teeth placed by 15 clinicians in the Danish Public Dental Health Service in 971 children, aged 3.6-14.9 yr. The restorations were performed using three resin-modified glass ionomer cements and one compomer (polyacid-modified composite resin) with and without their respective cavity conditioners. The restorations were in contact with 1023 unrestored proximal surfaces in 853 primary and 170 permanent teeth. The study was terminated after 7 yr with 1% of the restorations in function, 7% patient dropouts, 18% failed restorations, and operative treatment on 24% of the adjacent surfaces. Multivariate survival analyses showed that the restorative material and cavity conditioning influenced the survival of restorations but not the progression of caries on adjacent surfaces. The 50% survival times were estimated to exceed 5 yr for the restorations and 4.5 yr for the adjacent unfilled surfaces in all treatment groups. It was concluded that resin-modified glass ionomer cement and compomer are both appropriate materials for class II restorations in primary teeth. The differences in longevity and cariostatic effects among the four materials used with and without conditioner were less than the intra-individual differences between clinicians.

Acrylic Resins↗
PubMedDate not supplied

Materials for restoration of primary teeth: 2. Glass ionomer derivatives and compomers.

A wide variety of materials have been used for the restoration of primary teeth. Resin-modified glass ionomers and the more recently introduced viscous glass ionomers have been developed from conventional glass ionomer materials in an attempt to overcome the suboptimal properties of conventional glass ionomers. These materials would appear to have the necessary physical characteristics for restorations in load-bearing situations in primary teeth, as have the resin-based compomer materials, which now have well documented success rates in a number of studies. The first of these two articles described 'traditional' restorative materials, including amalgam and conventional glass ionomer, for the restoration of primary teeth. This paper describes materials derived from traditional glass ionomers in an attempt to overcome the suboptimal properties of conventional glass ionomers and resin-based materials such as compomer.

Child, Preschool↗
PubMed1997

Durability of a polyacid-modified composite resin (compomer) in primary molars. A multicenter study.

A polyacid-modified composite resin (compomer) restorative material was evaluated in primary molars in a multicenter study. One hundred and fifty-nine class-II restorations were placed by 6 dentists in 79 children. The restorations were evaluated during a 2-year period, using slightly modified USPHS criteria. After 1 year 151 restorations were evaluated and, after 2 years, 104. The cumulative failure rate after 1 year was 8% and after 2 years, 22%. The main reasons for failure were loss of retention (12%) and secondary caries (5%). The compomer material showed a high failure rate, comparable to that of other adhesive restorative materials currently used in primary molars. A large operator variation in failure rate indicates the technique sensitivity of the material.

Adhesives↗
PubMedDate not supplied

Clinical evaluation of a polyacid-modified resin composite (compomer) in Class II restorations of primary teeth: a two-year follow-up study.

PURPOSE: The aim of the study was to assess the clinical performance of a compomer restorative material (Dyract, DeTrey/Dentsply) for the restoration of Class II cavities, extended into dentin in primary teeth. METHODS: The sample of the study consisted of 25 patients with 68 restored cavities. The restorations were evaluated with the modified Ryge criteria at baseline and after 6, 12 and 24 months. Examination was clinical, radiographic, and observation of cast replicas under scanning electron microscope (SEM). RESULTS: After 24 months, 100% of the restorations were retained, 3% presented bulk fractures, and 6% developed secondary caries at cervical margins. After 24 months, there was a significant reduction in marginal integrity while there was only slight change in anatomic form. Proximal contact was defective in 6% of the restorations and 8% showed marginal discoloration. SEM evaluation revealed a generalized occlusal and scattered marginal wear with no marginal gaps. CONCLUSION: The compomer presented acceptable clinical performance in Class II restorations of primary teeth after 24 months in service.

Calcium Hydroxide↗
PubMed1999

Effect of surface conditioning on the shear bond strength of compomers to human primary and permanent enamel.

PURPOSE: To compare the bond strength of two polyacid-modified composite resins (Compomer) to primary and permanent enamel with and without acid-etching and to test for a possible relationship between the determined shear strength values and area of cohesive failure within the materials on the bonding interface. MATERIALS AND METHODS: Two compomer materials (Dyract and Compoglass) with their respective one-bottle primer/adhesive agents (Prime & Bond 2.0 and Syntac Single Component) were investigated. The parameters tested were shear strength and area of cohesive type of failure after debonding of specimens with respect to the total area of the bonding interface. RESULTS: Mean bond strength to primary enamel ranged from 4.09 MPa (Compoglass) to 5.6 MPa (Dyract), while in permanent enamel the mean values were between 12.3 MPa (Compoglass) and 14.3 MPa (Dyract), when pretreatment was made with bonding agents only. Generally, acid-etching prior to pretreatment improved adhesion significantly (6.0 MPa and 8.1 MPa in primary enamel and 16.0 MPa and 19.4 MPa in permanent enamel for Compoglass and Dyract, respectively). Over one-half of the variation in the values for cohesive failure area was explained by its linear relationship with shear bond strength.

Acid Etching, Dental↗
PubMedDate not supplied

Compomers, reattachment method expand restoration capabilities.

The purpose of this article is to review one new material and one new technique being used in restorative dentistry today. Compomers, new fluoride-releasing resin restorative materials, are compared to conventional glass ionomers in terms of classification, physical properties, and clinical usage. Compomers are not true glass ionomer materials since the acid/base setting reaction, charactheristic of conventional glass ionomers, does not occur. As a consequence, their physical properties of translucency, coefficient of thermal expansion, and strength more closely resemble composite resins than conventional glass ionomers. These differences in physical properties have clinical implications in their usage. In terms of new techniques, clinical and laboratory data now exist to support the method of reattachment of fractured tooth fragments using only dentin bonding agents, in cases where the tooth fragment is available. This method can restore up to 50 percent of the original strength of intact teeth. The technique advocates the use of acid etching and enamel and dentin bonding, without any tooth preparation. In vitro studies have achieved total (100 percent) restoration of intact teeth by bonding a porcelain veneer to the tooth after the reattachment.

Compomers↗
PubMed1999

What is a "compomer"?

"Compomers" are recently introduced products marketed as a new class of dental materials. These materials are said to provide the combined benefits of composites (the "comp" in their name) and glass ionomers ("omer"). Based on a critical review of the literature, the author argues that "compomers" do not represent a new class of dental materials but are merely a marketing name given to a dental composite.

Compomers↗
PubMed1999

Bond strength of compomers to dentin using acidic primers.

PURPOSE: To determine the in vitro bond strengths of seven compomer/bonding agent restorative systems to human dentin. MATERIALS AND METHODS: Seven compomer/bonding agents were bonded to human dentin, stored in water at 37 degrees C for 24 hours, and debonded in tension. Bonding conditions were with and without phosphoric acid etching, with and without the use of combined primer/bonding agents, and under moist and wet bond interfaces. RESULTS: Without phosphoric acid etching, F2000/F2000 Compomer Primer/Adhesive and F2000/Single Bond Dental Adhesive System were less sensitive to dentin wetness. With moist dentin, bond strengths of Dyract/Prime & Bond 2.1, Dyract AP/Prime & Bond 2.1, Hytac/OSB light-curing, one-component bonding agent, F2000/Single Bond, and Freedom/STAE single component light-cured dentin/enamel adhesive system, were improved with phosphoric acid etching. Also, with moist dentin, the bond strength of F2000/F2000 Compomer Primer/Adhesive in the 3M Clicker dispensing system was higher without phosphoric acid etching, whereas bonds of Compoglass/Syntac Single-component were not affected by phosphoric acid etching. Bonding did not occur without primer/bonding agent, regardless of surface condition or use of phosphoric acid etching.

Acid Etching, Dental↗
PubMed1999

Microleakage of composites and compomers in Class V restorations.

PURPOSE: To evaluate whether differences in material composition between various classes of resin-based composite and polyacid-modified resin-based composites (compomers) affect microleakage in Class V preparations. MATERIALS AND METHODS: Class V cavity preparations were made in the buccal/lingual surfaces of non-carious human molars with the occlusal margins in enamel and the gingival margins in dentin. Enamel margins were beveled, preparations etched, and a single bottle dentin bonding agent was applied. Preparations were restored with the following materials (n = 20): Heliomolar RO, Tetric Ceram, Tetric Flow, Flow-It, Flow-It LF, Compoglass F, and Compoglass Flow. Restorations were polished and teeth thermocycled, stained, and sectioned to evaluate both linear and penetrating microleakage. RESULTS: Within all groups there was significant increase (P < 0.05) in both linear and penetrating dentin microleakage when compared to enamel microleakage. Linear gingival microleakage results indicated that Compoglass Flow and Tetric Ceram had significantly less microleakage than Flow-It and Flow-It LF and that Compoglass Flow also had significantly less microleakage than Heliomolar RO. Heliomolar RO, Flow-It and Flow-It LF had significantly more penetrating dentin microleakage than Tetric Ceram. The fact that microleakage scores between groups of materials were not significantly different indicates that the ability to predict microleakage in Class V preparations among various classes of resin-based composite or compomer materials is a much more complex phenomenon than can be simply gathered from focusing on compositional differences alone.

Analysis of Variance↗
PubMedDate not supplied

Fluoride release from three glass ionomers, a compomer, and a composite resin in water, artificial saliva, and lactic acid.

The amounts and the pattern of fluoride release from one metal-reinforced glass ionomer cement, two resin-modified glass ionomer cements, one compomer, and one composite resin placed in double-distilled water, artificial saliva, and lactic acid were evaluated in this study. Measurements of fluoride ion release were made for a total of 105 cylindrical specimens (10 mm in diameter and 1.5 mm in height). They were taken over a period of 16 weeks at the intervals of 4, 8, 12, and 24 hours, as well as 2, 3, 7, 14, 28, 56, and 112 days. The pattern of fluoride release was similar for all of the examined materials. The greatest amount of fluoride was released from the metal-reinforced glass ionomer Argion. The resin-modified glass ionomers Vitremer, Fuji II LC; the compomer Dyract; and the composite resin Tetric followed in ranking order. The pH of the environment strongly affected the fluoride release from the materials. There was a significant difference (P < 0.001) in the amounts of fluoride released in lactic acid vs water and artificial saliva, whereas, there was no significant difference (P > 0.05) in the amounts of fluoride released in water vs artificial saliva.

Analysis of Variance↗
PubMedDate not supplied

Bond strength of compomers to human enamel.

The study evaluated the tensile bond strength between human enamel and seven compomer restorative systems under different bonding conditions. Seven compomers were bonded to human tooth structure with and without phosphoric acid etching of the bonding surface, with and without the use of their recommended combined primer and bonding agent and with both moist and wet bond interface environments. Overall, the highest bond strengths to human enamel were attained using phosphoric acid conditioning, primers and moist bonding surfaces.

Acid Etching, Dental↗