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PubMed1992

Adhesion between the resin shell and composite resin.

Adhesiveness between the resin shell and composite resin was examined. As the resin shell, SR-PE-ISOCETTE, made from thermosetting crown and bridge resin, was used. The shear bond strengths between the resin shell and photocurable composite resin bonded by various methods were measured after 1-day of immersion in water at 37 degrees C. Super-bond C & B treatment to the resin shell effectively improved the adhesiveness, giving a bond strength of about 14 MPa. Clearfil new bond, Clearfil porcelain bond, Unifast and MMA/TBBO treatment gave almost the same bond strengths of about 7-9 MPa. Silane coupling agents were not effective for improving the bond strength. It was revealed that 4-META was necessary for obtaining good adhesion between SR-PE-ISOCETTE and composite resin.

Boron Compounds↗
PubMed2001

Bioaugmentation with resin-acid-degrading bacteria enhances resin acid removal in sequencing batch reactors treating pulp mill effluents.

Resin acids are the major toxicants in pulp and paper mill effluents (PPMEs), and they form pitch interfering with papermaking. Efficient and reliable resin acid removal is critically important to prevent toxicity discharge and ensure proper functioning of paper machines. Two resin-acid-degrading bacteria, Pseudomonas abietaniphila BKME-9 and Zoogloea resiniphila DhA-35, were tested in laboratory sequencing batch reactors (SBRs) for their ability to enhance resin acid removal by biomass from a full-scale biotreatment system treating PPMEs. Both bacteria enhanced resin acid removal but not removal of total organic carbon (TOC) by either pH-shocked or starved activated sludge. These two bacteria also increased resin acid removal when the sludge was given high concentration (200 microM) of resin acid. A most-probable-number polymerase chain reaction (MPN-PCR) assay showed that these two bacteria were initially not detectable (detection limit: 10(2) bacterial cells/ml) in the sludge community and were persistent after inoculation. Both bacteria did not substantially change the indigenous microbial community composition, as assayed by ribosomal intergenic spacer analysis (RISA). Our results suggest that it is feasible and potentially useful to enhance resin acid removal by bioaugmentation using resin-acid-degrading bacteria such as BKME-9 and DhA-35.

Abietanes↗
PubMed2004

Effects of saliva contamination on resin-resin bond strength.

OBJECTIVE: The purpose of this study is to evaluate the effects of saliva contamination on microtensile bond strength (microTBS) between resin interfaces and to determine which decontamination methods best re-established the original resin-resin bond strength. MATERIALS AND METHODS: Ninety-six light-cured resin composite cylinders of Z-250, Renew, Clearfil APX, and Pertac II were randomly divided into six groups. For each material, one group of specimens was not contaminated, serving as the control. For the other specimens, the top surface of each block was treated with saliva that was slowly dried (Treatment 1); dried forcefully (Treatment 2); slowly dried, rinsed, and dried (Treatment 3); slowly dried, rinsed, dried, and bonded with Single Bond, One-Step, Clearfil SE Bond, or Prompt L-Pop (Treatment 4); or slowly dried, but not rinsed, and bonded using the same adhesives (Treatment 5). Two 2-mm increments of resin composite were applied and light-cured. After 24 h, the assemblies were trimmed for microtensile bond testing and were loaded to failure at 1 mm/min. Data were analyzed using two-way and one-way ANOVA and Fisher's PLSD (p<0.05). RESULTS: Control values ranged from 45.1 MPa for Pertac II to 71.5 MPa for APX. Treatment 1 caused significant reduction in resin-resin bond strength for all materials tested but for two of the materials in treatment 2. Pertac II was the only material that did not show a statistical difference from control group for treatment 3. Treatment 4 re-established the control values for Z-250 and Renew and treatment 5 was the only one to show no statistical difference for all materials tested. SEM observation revealed a smooth surface in treatment 1, but treatment 3 showed a few craters. Treatment 4 and 5 showed a mixture of cohesive failure in the composite and adhesive. SIGNIFICANCE: The most reliable method for decontaminating saliva from resin surfaces involves the application of adhesives.

Adhesiveness↗
PubMed2004

Effects of blood contamination on resin-resin bond strength.

OBJECTIVE: Incremental placement and curing of resin composites has been recommended. However, this requires longer operating time, and therefore, increased risk of contamination. The purpose of this study was to evaluate the effects of blood contamination on microtensile bond strengths (microTBS) between resin interfaces and to determine the best decontamination method to re-establish the original resin-resin bond strength. MATERIALS: The top surfaces of 64, 4-mm composite blocks (Z-250, Renew, APX, Pertac II) were untreated as the control, or were treated as follows: blood applied and dried on the surface (Treatment 1), blood applied, rinsed, dried (Treatment 2), blood applied, rinsed, and an adhesive applied (Single Bond, One-Step, Clearfil SE, Prompt L-Pop) (Treatment 3). Fresh composite was applied and light-cured in 2-mm increments. After 24 h storage in water, the specimens were sectioned into 0.7-mm thick slabs, trimmed to a cross-sectional area of 1 mm(2), and loaded to failure at a crosshead speed of 1 mm/min using an Instron universal testing machine. Data were analyzed using two-way ANOVA and Fisher's PLSD test (p<0.05). RESULTS: Control values ranged from 45.1 MPa for Pertac II to 71.5 MPa for APX. Untreated blood contamination resulted in resin-resin bond strengths of only 1.0-13.1 MPa. Rinsing raised bond strengths to over 40 MPa for each material. Use of an adhesive further increased bond strengths except for Pertac II. SIGNIFICANCE: Rinsing blood from contaminated surfaces increases the resin-resin bond strength significantly and the application of an appropriate adhesive increases the bond strength to control levels.

Analysis of Variance↗
PubMedDate not supplied

Enamel and dentine shear bond strength of two resin modified glass ionomers and two resin based adhesives.

OBJECTIVES: The purpose of this in vitro study was to compare the shear bond strength to enamel and dentine of two resin modified glass ionomers (Fuji Bond L.C. and Vitrebond) and two resin based adhesives (Prime&Bond 2.1 and Scotchbond Multi-Purpose). METHODS: A total of 120 bond sites were prepared on either enamel (n = 60) or dentine (n = 60) on human molars by grinding the teeth flat with a 600 grit sandpaper. Each tooth substrate group was divided into four groups (n = 15) to match each material. Each of the four material systems was applied, according to the manufacturers instructions, to the bond sites. On top of the placed material, a microfilled composite was placed in a 2.5 mm diameter matrix and light-cured for 40 s. All specimens were thermocycled 500 times (5-55 degrees C). Shear bond strength values were determined 120 h after bonding using a Zwick testing machine. One-way ANOVA was used to determine whether significant differences (p < 0.05) existed among the material groups on enamel and dentine. Pairwise comparisons were used to determine significant differences (p < 0.05) among the four products. RESULTS: The ANOVA revealed strong significant differences on enamel (p = 0.0001) and dentine (p = 0.0172). The enamel bond strength values of the two resin based adhesives were significantly higher than one of the resin modified glass ionomers (Vitrebond), while the other resin modified glass ionomers did not differ from Scotchbond Multi-Purpose. On dentine, however, Vitrebond performed significantly better than the two resin based adhesives. CONCLUSIONS: The investigated resin modified glass ionomers bonded better to dentine surfaces than to enamel surfaces, while the investigated resin based adhesive systems bonded better to enamel than to dentine.

Adhesives↗
PubMed2002

In vivo bracket retention comparison of a resin-modified glass ionomer cement and a resin-based bracket adhesive system after a year.

Glass ionomer orthodontic adhesives cause less enamel demineralization during fixed orthodontic appliance treatment than do traditional resin-based products. An in vivo randomized clinical trial was performed comparing the clinical performance of a resin-modified glass ionomer (RMGI) adhesive with a no-mix, resin-based (the control) adhesive over a 12-month period. The split-mouth technique was used to analyze bracket retention, bracket failure causes, and mode of failure for both adhesives in 61 patients. Bracket-failure rates were 10% for the RMGI and 4% for the resin-based adhesive. Both adhesives had 4 times more bracket failures when opposing occlusion was present. The resin-based product demonstrated a higher proportion of resin-to-enamel adhesive failures than did the RMGI. Compared with the resin-based adhesive, the RMGI-bracketed teeth showed improved clinical performance, no enamel surface loss, less enamel demineralization, and faster adhesive removal. However, the RMGI had a 2.6 times greater bracket-failure rate than did the resin-based product.

Adolescent↗
PubMedDate not supplied

5-year clinical performance of resin composite versus resin modified glass ionomer restorative system in non-carious cervical lesions.

AIM: To comparatively assess the 5-year clinical performance of a 1-bottle adhesive and resin composite system with a resin-modified glass ionomer restorative in non-carious cervical lesions. METHOD AND MATERIALS: One operator placed 70 restorations (35 resin modified glass ionomer restorations and 35 resin composite restorations) in 30 patients under rubber dam isolation without mechanical preparation. The restorations were directly assessed by 2 independent examiners, using modified USPHS criteria at baseline and 6, 12, 24 and 60 months. RESULTS: Twenty-two patients were available for recall after 5 years (73.3% recall rate) and 55 out of 70 restorations were evaluated. Excellent agreement was registered for all criteria between examiners (kappa > or = 0.85). Sixteen composite restorations were dislodged (51.5% retention) and 1 ionomer restoration was lost (96.4% retention). The McNemar test detected significant differences in resin composite restorations between baseline and 5-year recall for marginal integrity (p<0.001) and retention (p=0.004). For resin modified glass ionomer restorations, no significant differences were identified for all criteria (p>0.05). When comparing both materials, the Fisher exact test pointed out significant differences in retention (p=0.002) after 5 years of clinical service. CONCLUSIONS: After 5 years of evaluation, the clinical performance of resin modified glass ionomer restorations was superior to resin composite restorations.

Acid Etching, Dental↗
PubMed1987

Marginal adaptation of composite resin restorations placed with or without intermediate low-viscous resin. An SEM investigation.

The marginal adaptation to acid-etched enamel of a hybrid and a microfilled composite resin, placed with or without intermediate low-viscous resin, was investigated in vivo. Each of 37 patients received four class III test fillings, one with each filling technique. The evaluation was done with the use of SEM on replicas from the cavity margins, 1 week and 1 year after insertion of the fillings. The observed defects were marginal cracks or fractures, chip fractures, and enamel fractures. In the comparison of the size and volume of the marginal defects no significant differences were seen after 1 week between fillings of the same material placed with or without an intermediate resin. However, after 1 year the hybrid resin fillings with an intermediate resin showed significantly better adaptation than the ones without. No difference was found between the microfilled resin fillings. The hybrid resin fillings showed significantly better marginal adaptation than the microfilled resin fillings after 1 week. A further increase of the differences was observed after 1 year.

Adhesives↗
PubMed2003

Optical properties of paint-on resins for shade modification of crown and bridge resins--light transmittance characteristics--.

The purpose of this study was to examine the light transmittance characteristics of the paint-on resins for shade modification. Three shades of paint-on resin, one crown and bridge resin, and human enamel were used. Specimens with four different thicknesses (75-150 microm) were prepared. The light transmittances including its wavelength distribution and diffusion characteristics were measured. The color values and the color differences among thicknesses of specimens were also determined. The light transmittance values of the paint-on resins ranged from 60.3% to 88.3% at 100 microm thickness, which were lower or nearly equal in comparison with the crown and bridge resin and enamel. Although differences in the wavelength distribution of transmittance among materials were found at lower wavelengths, all materials showed similar diffusion characteristics. The thin layer of paint-on resin effectively changed the color of restorative resin. The paint-on resin may be an effective material for the modification of the color appearance matching required.

Color↗
PubMed1986

The effect of resin formulation on the degree of conversion and mechanical properties of dental restorative resins.

The goal of this study was to determine the effects of resin formulation variables, such as diluent concentration, catalyst type and concentration and cure mode, on the degree of conversion of carbon double bonds and mechanical properties of dental restorative resins. Diametral tensile strength, compressive strength, hardness, flexural modulus and strength, and dynamic mechanical properties were tested, and the results were correlated to the degree of conversion results obtained by infrared analysis. The results showed a significant correlation between increased mechanical properties and higher degrees of conversion. Enhanced conversions were achieved by incorporating higher diluent and lower inhibitor concentrations into the resins. Ambient temperature properties were similarly enhanced by lower inhibitor concentrations, but were not enhanced by higher diluent concentration. Dynamic mechanical properties testing at oral and elevated temperatures elucidated possible differences in resin microstructure and network quality. The storage moduli decreased over the dental temperature range and was lower at all temperatures for resins with lower conversions. The glass transition temperature was also lower in resins with poorer conversions, suggesting that these resins may be more unstable at oral temperatures than more highly converted resins. Dynamic mechanical properties were most closely correlated to degree of conversion in these polymeric systems.

Acrylic Resins↗
PubMed2004

Thermal expansion characteristics of light-cured dental resins and resin composites.

The thermal expansion characteristics of dental resins prepared by light-curing of Bis-GMA, TEGDMA, UDMA, Bis-EMA(4) or PCDMA dimethacrylate monomers and of commercial light-cured resin composites (Z-100 MP, Filtek Z-250, Sculpt-It and Alert), the organic matrix resin of which is based on different combinations of the above monomers, were studied by thermomechanical analysis (TMA). This study showed the existence of a glass transition temperature at around 35-47 degrees C for the resins and 40-45 degrees C for the composites; then the coefficient of linear thermal expansion (CLTE) was calculated at the temperature intervals 0-60 degrees C, 0-T(g) and T(g)-60 degrees C. The CLTE values of Bis-GMA, TEGDMA and UDMA resins are similar and lower than those of Bis-EMA (4) and PCDMA resins. The CLTE values of the composites indicated that the major factor that affects the CLTE of a composite is the filler content, but it also seems to be affected by the chemical structure of the matrix resin. TMA on water-saturated samples showed that water desorption takes place during the measurement and that the residual water acts as a plasticizer decreasing the T(g) and increasing the CLTE values. Furthermore, TMA on post-heated samples for 1, 3 or 6h showed, only for the resins, an initial decrease of CLTE and increase of the T(g) after 1h that was not significantly changed after 6h of heating.

Composite Resins↗
PubMed2001

Comparison of chromatographic ion-exchange resins. II. More strong anion-exchange resins.

A comparative study was performed on strong anion exchangers to investigate the pH dependence, titration curves, efficiency, binding strength, particle size distribution, and static and dynamic capacity of the chromatographic resins. The resins tested included Q Sepharose XL, UNO Q-1, Poros 50 HQ, Toyopearl QAE 550c, Separon HemaBio 1000Q, Q-Cellthru Bigbeads Plus, Q Sepharose HP and Toyopearl SuperQ 650s. Testing was performed with five different proteins: anti-Factor VII monoclonal antibody (immunoglobulin G), aprotinin, bovine serum albumin, lipolase and myoglobin. The dependence of pH on retention varies from generally low to very high for proteins with a low isoelectric point (pl). An unexpected binding at pH 7-8 of aprotinin with pI >11 was observed on Separon HemaBio 1000Q. No link between pH dependence on retention and titration curves of the different resins was observed. Efficiency results show the expected trend of higher dependence of the plate height with increasing flow-rate of soft resins compared to resins for medium- and high-pressure operation. No or a very small difference in particle size distribution was obtained between new and used resins. Binding to anion-exchange resins as a function of ionic strength varies to some extent depending on the specific protein. Generally, binding and elution at high salt concentration may be performed with Q Sepharose XL, Toyopearl QAE 550c, Q Sepharose HP and Poros 50 HQ, while binding and elution at low salt concentration may be performed with Q-Cellthru Bigbeads Plus. A very high binding capacity was obtained with Q Sepharose XL. Comparison of static capacity and dynamic capacity at 10% breakthrough shows approx. 50-80% utilization of the total available capacity during chromatographic operation. A general good agreement was obtained between this study and data obtained by the suppliers. The results of this study may be used for selection of resins for testing in process development.

Anion Exchange Resins↗
PubMed2000

The effect of phosphoric acid concentration on resin tag length and bond strength of a photo-cured resin to acid-etched enamel.

OBJECTIVES: To determine the relationship between depth of penetration and tensile bond strength of a photo-cured resin to phosphoric acid etched enamel, and the efficacy of enamel etchants that are less aggressive than a concentration of 10% H3PO4. METHODS: The tensile bond strength and length of tags produced by a photo-cured (20 s) resin consisting of pre-polymerized TMPT/silica in 3% HNPM-TEGDMA on acid-etched enamel was determined. The enamel etchants tested were various concentrations (3-65%) of phosphoric acid. The resin was applied to enamel samples that had been abraded with No. 600-grit SiC paper and acid etched (30 s) to create test specimens that were loaded to fracture on a testing device. The HCl-treated, then cut specimens, were examined under scanning electron microscopy and light microscopy. RESULTS: The tensile bond strength (10 MPa) of resin to enamel, pre-treated with various acid concentrations did not vary significantly. But resin tag length was found to decrease significantly from 22 microns for 35% H3PO4 to 12 microns for 20% H3PO4 to 9 microns for 5, 10 and 65% H3PO4 to 5 microns for 3% H3PO4. SIGNIFICANCE: These findings suggest that the length of the tags created by the tested photo-cured resin on phosphoric acid-etched enamel contributes little to the bond strength of the test specimens, and that the adhesive strength of the resin to H3PO4 etched enamel is mainly attributable to the resin's ability to penetrate between the enamel crystallites and rods. Further, enamel pre-treatment by phosphoric acid etchants of concentrations lower than 10% may be satisfactorily employed. The use of less aggressive acid concentrations might minimize any potential adverse effects to enamel substrates.

Acid Etching, Dental↗
PubMed2005

Effect of polysulfonate resins and direct compression fillers on multiple-unit sustained-release dextromethorphan resinate tablets.

The purpose of this work was to investigate the effect of different polysulfonate resins and direct compression fillers on physical properties of multiple-unit sustained-release dextromethorphan (DMP) tablets. DMP resinates were formed by a complexation of DMP and strong cation exchange resins, Dowex 50 W and Amberlite IRP69. The tablets consisted of the DMP resinates and direct compression fillers, such as microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), and spray-dried rice starch (SDRS). Physical properties of tablets, such as hardness, disintegration time, and in vitro release, were investigated. A good performance of the tablets was obtained when MCC or SDRS was used. The use of rod-like and plate-like particles of Amberlite IRP69 caused a statistical decrease in tablet hardness, whereas good tablet hardness was obtained when spherical particle of Dowex 50 W was used. The plastic deformation of the fillers, such as MCC and SDRS, caused a little change in the release of DMP. A higher release rate constant was found in the tablets containing DCP and Dowex 50 W, indicating the fracture of the resinates under compression, which was attributable to the fragmentation of DCP. However, the release of DMP from the tablets using Amberlite IRP69 was not significantly changed because of the higher degree of cross-linking of the resinates, which exhibited more resistance to deformation under compression. In conclusion, the properties of polysulfonate resin, such as particle shape and degree of cross-linking, and the deformation under compaction of fillers affect the physical properties and the drug release of the resinate tablets.

Compressive Strength↗
PubMed2003

Tooth brush abrasion of paint-on resins for shade modification of crown and bridge resins.

The purpose of this study was to evaluate the surface roughness and resistance to toothbrush abrasion of three experimental paint-on composite resins developed for the shade modification of crown and bridge resins. The paint-on resins had less filler volume fraction than restorative composites or the crown and bridge resins and consequently were of low viscosity. The maximum surface roughness (Rmax) and the maximum depth loss by abrasion for the paint-on resins following 40,000 cycles of brushing ranged from 2.45 to 4.07 microm and 8.63 to 13.67 microm, respectively. Rmax values were 37.7-67.5% lower than that for the crown and bridge resin subjected to the same test. Wear depth was 19.9-49.4% lower than for the crown and bridge resin. These results suggest that the paint-on resins are expected to have adequate resistance to toothbrush abrasion and may therefore be suitable for clinical use.

Color↗
PubMed1989

[Dental resin for restoration with unsaturated polyester resin used as base material. Effect of catalyst, accelerator and subaccelerator on working time, setting time and peak temperature].

The fatal demerit of resin materials which causes a marginal sealing defect or marginal fracture is hard to eliminate. A series of studies seeking for dental resin for restoration having no polymerization shrinkage, applying polyester resin used as base resin. This study was conducted to promote the improvement of composite resin, in which the author examined the composition with catalyst, accelerator and subaccelerator having preferable working time, setting time and peak temperature which is not clear, so as to obtain the fundamental data. In accordance with the increase in the amount of catalyst, accelerator and subaccelerator added, peak temperature showed a tendency to increase. Contrarily, working time and setting time showed a tendency to decrease. The composition showing preferable working time, setting time and peak temperature, is as follows: to the base resin, polyester with 38 wt% of shrinkage inhibitor mixed, catalyst by 1.0 wt%, accelerator by 0.50 wt% and subaccelerator by 0.02 wt% were added. The trial product of composite resin a 70 wt% of surface-treated glass beads added showed a working time of 2.3 minutes, setting time of 9 minutes and peak temperature of 57.0 degrees C, approximately the same values as of commercial composite resin.

Dental Restoration, Permanent↗