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PubMed1989

The wettability of bonding resins used in the composite resin/glass ionomer 'sandwich technique'.

There is some controversy about the significance of the wettability of the unfilled resin bonding agent that is generally recommended for prior application when placing a composite resin restoration. It has been suggested that the degree of viscosity does not matter. However, when investigating the union which is developed between composite resin and glass ionomer cement in the 'sandwich technique', it was noted that when using certain composite resins and their prescribed bonding resins the failure under tensile stress was adhesive at the union rather than cohesive in the cement. Further investigation showed that the bonding resins involved in these failures were more viscous than those bonding resins used in the more successful unions. In this investigation the contact angle of the bonding resin on the surface of glass ionomer cement was used as the measure of viscosity. It is suggested that the degree of viscosity of the bonding resin is significant in the success or otherwise of the 'sandwich technique'.

Acid Etching, Dental↗

PubMed1988

Adhesive 4-META/MMA-TBB opaque resin with poly(methyl methacrylate)-coated titanium dioxide.

An adhesive opaque resin for veneering on cast metal was developed with 4-methacryloxyethyl trimellitate anhydride and poly (methyl methacrylate)-coated titanium dioxide prepared by aqueous phase polymerization. The opaque resin was a modified 4-META/MMA-TBB resin. The powder consisted of 20% of the encapsulated material and 80% PMMA instead of pure PMMA powder. This resin hides the metal color when the thickness of the resin is as thin as 50 microns. The opaque resin bonded strongly to both cobalt-chromium alloy and visible-light-cured veneering resin. This self-curing opaque resin is applicable not only for bonding veneering resin to an alloy surface but also for bonding fixed partial dentures to enamel surfaces.

Acrylic Resins↗

PubMed2000

The physical properties of packable and conventional posterior resin-based composites: a comparison.

BACKGROUND: The authors compared the physical properties of three packable hybrid resin-based composites with those of a conventional hybrid and a microfill composite material advocated for use as posterior restorative materials. They evaluated diametral tensile strength, or DTS; compressive strength, or CS; flexural strength, or FS; and depth of cure, or DC. METHODS: The authors studied the following resin-based restorative materials: three packable composites, Alert Condensable Composite (Jeneric Pentron), SureFil High Density Posterior Restorative (Dentsply Caulk) and Solitaire (Heraeus Kulzer); one conventional hybrid composite, TPH Spectrum (Dentsply Caulk); and one microfill, Heliomolar Radiopaque (Ivoclar-Vivadent). The authors evaluated DTS, CS, FS and DC, according to American National Standards Institute criteria. They made scanning electron micrographs of the packable resin-based composites. RESULTS: Results demonstrated that the conventional hybrid, TPH Spectrum, had significantly greater DTS and FS than other resin-based composites. Alert and SureFil had comparable DTS and FS, which were significantly greater than Heliomolar's DTS and FS. Solitaire had significantly lower DTS and FS than all other resin-based composites. SureFil had the highest CS, followed by TPH Spectrum, Solitaire and Alert, which were comparable and had significantly greater CS than Heliomolar. TPH Spectrum and Alert had significantly greater DC than all other resin-based composites, followed in decreasing order by SureFil, Solitaire and Heliomolar. CONCLUSION: While the packable composites tested in this study had physical properties superior to those of the microfill composite, they were no better suited for use as a posterior restorative material than was the conventional hybrid resin-based composite. CLINICAL IMPLICATIONS: Packable composites may be easier for clinicians to handle than conventional resin-based composites; however, their physical properties were not superior to those of the conventional small-particle hybrid resin-based composite. In addition, these materials may have the clinical drawback of increased wear and surface roughness that was seen with early, large-particle composite restorative materials.

Acrylic Resins↗

PubMedDate not supplied

Efficacy of a self-curing adhesive-resin cement system on luting glass-fiber posts into root canals: an SEM investigation.

PURPOSE: The aim of this study was to evaluate the efficacy of a new bonding-luting system in resin tag, adhesive lateral branch, and hybrid layer formation when used in combination with an experimental fiber post. MATERIALS AND METHODS: Thirty anterior teeth extracted for periodontal reasons were selected for this study. They were endodontically treated and randomly divided into three groups of 10 samples each: group 1 = Excite light-cured bonding agent in combination with Variolink II resin cement; group 2 = Excite dual-cured bonding agent self-activated by an experimental microbrush in combination with MultiLink resin cement; and group 3 = one-step bonding system in combination with Dual Link resin cement. In groups 1 and 3, the primer-adhesive solution was light cured before placing the resin cement and the post, whereas in group 2 the adhesive/luting materials were not light cured. Twenty FRC Postec translucent posts (groups 1 and 2) and 10 EndoAesthetic translucent fiber posts (group 3) were used. One week later, the root samples were processed for scanning electron microscopic (SEM) observations. RESULTS: Microscopic examinations of restored interfaces from group 2 revealed a resin-dentin interdiffusion zone higher than that seen in samples from groups 1 and 3 (P < .05). At the apical and middle thirds, the samples from group 2 showed significantly more resin tags than the other two groups. CONCLUSION: The dual-cure self-activating system showed a more uniform resin tag and resin-dentin interdiffusion zone formation along root canal walls than light-curing systems.

Acid Etching, Dental↗

PubMed2003

Evaluation of marginal microleakage in class II cavities: effect of microhybrid, flowable, and compactable resins.

OBJECTIVE: The goal of the present study was to evaluate the microleakage on the cementum/dentin and enamel surfaces in Class II restorations, using different kinds of resin composite (microhybrid, flowable, and compactable). METHOD AND MATERIALS: Forty human caries-free molars were extracted and selected. Eighty Class II standardized cavities were made in the cervical wall at the cementoenamel junction (CEJ) and at the mesial and distal surfaces. The teeth were divided into four groups: G1--adhesive system + microhybrid resin composite Z100; G2--adhesive system + compactable resin composite Prodigy Condensable; G3--adhesive system + flowable resin composite Revolution + Z100 resin composite; G4--adhesive system + Revolution fluid resin + compactable resin composite Prodigy Condensable. The adhesive system used in this study was Scotchbond Multi-Purpose Plus. The specimens were thermocycled in baths of 5 degrees C and 55 degrees C for 1,000 cycles and immersed in 50% silver nitrate solution. The specimens then were sectioned and evaluated on degree of dye penetration. RESULTS: The results were evaluated using the nonparametric Kruskall-Wallis test, which showed a statistically significant difference between groups G1 and G4, G2 and G4, and G3 and G4. CONCLUSIONS: None of the materials was able to eliminate the marginal microleakage at the cervical wall; the application of a low-viscosity resin composite combined with a compactable resin composite significantly decreased the microleakage.

Composite Resins↗

PubMedDate not supplied

Analysis of the enamel/adhesive resin interface with laser Raman microscopy.

Adhesion of resin composites into enamel is currently believed to rely on infiltration of bonding resin into the porous zone, establishing micromechanical retention to etched enamel. This study investigated the change in chemical composition of the enamel/resin interface using a laser Raman microscopic system (System-2000, Renishaw). Two-step bonding systems, Mac Bond II (Tokuyama Corp), Clearfil Mega Bond and Single Bond (3M/ESPE) were employed. Resin composites were bonded to bovine enamel with bonding systems and sectioned through the bonded interface. The sectioned surfaces were then polished with diamond pastes down to 1.0 microm particle size. Raman spectra were successively recorded along a line perpendicular to the enamel/ resin interface. The sample stage was moved in 0.2 microm increments on a computer-controlled X-Y precision table. Additional spectra from samples of enamel and cured bonding resins were recorded for reference. The relative amounts of the hydroxyapatite (960cm(-1), P-O), bonding agent (640cm(-1), aromatic ring) and alkyl group (1450cm(-1), C-H) in the enamel/resin bonding area were calculated. From Raman spectroscopy, a gradual decrease in hydroxyapatite was observed, and it was estimated to extend 2.2-2.6 microm for Mac Bond II, 1.2-1.6 pm for Clearfil Mega Bond and 5.2-5.6 microm for Single Bond. Furthermore, the enamel/resin interface represents a gradual transition of bonding agent from the resin to tooth side. Evidence of poor saturation of adhesive resin in etched enamel with Single Bond was detected. From the results of this study, non-uniform resin infiltration into etched enamel was detected and the degree of resin infiltration was found to be different among the bonding systems used.

Acid Etching, Dental↗

PubMed2006

Pulpal response to a newly developed MMA based resin cement for bonding tooth-colored indirect restorations.

PURPOSE: To evaluate the pulpal responses to a newly-developed MMA-based self-etch resin cement, when used as a luting agent for indirect resin composite restoration, and to compare the results with those obtained from a total-etch luting agent, glass-ionomer cement, and amalgam restoration. METHODS: 120 cervical cavities were prepared in monkey teeth and divided into four equal groups according to the restorative materials used: (1) the cavities were restored with resin composite inlays using a self-etch resin cement as a luting agent (M-Bond); (2) the cavities were also restored with resin composite inlays but using a total-etch resin cement as a luting agent (Super-Bond C & B); (3) the cavities were directly restored with glass-ionomer cement (Fuji II); or (4) the cavities were directly restored with amalgam (Dispersalloy). The restored teeth were extracted at 3, 30, or 90 days after restoration, then fixed in 10% neutral buffered formalin. The specimens were prepared using routine histopathological procedures. Five microm-thick sections were stained with hematoxylin and eosin or Brown & Brenn gram stain for bacterial observations. Histological responses in the pulpal tissue and bacterial penetration were observed under a light microscope and evaluated using standard scores. The results were statistically analyzed using the Kruskal-Wallis test (P< 0.05). RESULTS: At all time intervals, no significant differences of pulpal inflammatory responses between M-Bond and Super-Bond C&B were observed (P> 0.05). Both resin cements showed no serious pulpal responses, such as necrosis or abscess formation. In general, both MMA-based resin cements showed similar pulpal responses to those of glass-ionomer cement except for congestion of pulpal blood vessels at 3 days after restoration in which glass-ionomer cement exhibited a lower level than that of the MMA-based resin cements. For the group restored with amalgam, at 3 days after restoration, severe odontoblastic disorders and blood vessel congestions with a large infiltration of inflammatory cells were detected. At 30 and 90 days after restoration, slightly inflammatory irritations were observed irrespective of the materials used. Reparative dentin formation and bacterial penetration were found mostly in the group restored with amalgam.

Analysis of Variance↗

PubMed1981

Tags penetrating dentin of a new adhesive resin.

The change of the dentinal tubules by acid-etching and the morphology and the adhering state of new adhesive composite resin tags penetrating the tubules were observed by SEM, comparing with the representative conventional composite resin. When the fractured surface of the unetched floor dentin were observed, all tubule entrances were closed by blocking with cutting debris up to 10 to 20 micrometers depth. Etching opened them by dissolving the debris and further widened the tubule entrances up to 10 to 20 micrometers depth by dissolving the peritubular dentin near the apertures. Resin tags penetrated 10 to 20 micrometers in vital teeth, 60 to 100 micrometers in freshly extracted teeth and several hundred micrometers in old extracted teeth. The tags of the new resin penetrating the tubules copied exactly the shape of the tubule walls, producing hollow depressions at the ends, indicating that the renin polymerized, adhering tightly to the walls, while those of the conventional resin produced highly tapered side walls with pointed ends, indicating that the resin shrank separating from the tubule walls on polymerization. The new resin did not produce any gap at the resin-dentin interface unlike the conventional resin.

Acid Etching, Dental↗

PubMed1980

[Bathocuproine disulfonic acid-loaded resin as a preconcentrating agent of trace mercury (author's transl)].

A chelating agent-loaded resin consisting of an anion exchange resin (Dowex 1 X-4) and bathocuproine disulfonic acid (BCS-resin) was prepared. The adsorption behavior of some chalcophile elements as a function of pH by the column method was studied, and mercury was shown to be adsorbed selectively to the BCS-resin at the pH region of 0.5 approximately 1.0, and the BCS-resin was found to be a specific collector for trace mercury in natural water samples before neutron activation analysis. The molar ratio of BCS to mercury(II) in the resin was confirmed to be 1:1 and the resulting chelate was stable at least within a month. The method was applied to the determination of mercury in the Watarase river water sample. The sample solution was adjusted to pH 1.0 with HNO3, filtered and flown through the column (BCS-resin: 4 x 10(-4) mol . g-1 . resin, 7 mm phi x 35 mmH) and the resin was then washed and dried in a desiccator. The monitor containing 10 micrograms of mercury was also prepared according to the above scheme. The samples and the monitor were irradiated together in the pneumatic tube of JRR-3 for 60 min (neutron flux: 2 x 10(13) n . cm-2 . s-1). After cooling for 15 days, gamma-activity of 203Hg was measured. The result was 21 +/- 3 ppt for mercury, indicating that the method was well applicable to the determination of trace mercury in river water samples.

Anion Exchange Resins↗

PubMed1993

Shear bond strengths of two luting cements to laboratory-cured prosthetic resin composite.

This study evaluated the effect of four types of surface preparations for laboratory-cured prosthetic resin composite on the shear bond strengths of glass ionomer and resin luting cements. Two sizes of light-cured resin composite disks were treated and cemented with two types of luting cements. The specimens were stored in 37 degrees C water for up to 16 weeks before shear mode testing at a crosshead speed of 0.5mm/min in an Instron. The application of dichloromethane and an unfilled bonding resin was an effective surface treatment which improved the shear bond strength of glass ionomer cement to resin composite compared with no-treatment. However, the resin composite, treated with dichloromethane and then coated with bonding resin containing a silane coupler, followed by cementation with resin cement, consistently yielded the strongest shear bond strength with cohesive failures occurring within the resin composite for all specimens.

Analysis of Variance↗

PubMed2006

Soil bacteria are differentially affected by the resin of the medicinal plant Pseudognaphalium vira vira and its main component kaurenoic acid.

The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudognaphalium vira vira. As some diterpenoids have antimicrobial properties, the effect of this resin and the kaurenoic acid on soil bacteria was studied. The resin of P. vira vira and purified kaurenoic acid were two to four times more effective as antibacterial agents with Gram-positive than with Gram-negative soil isolates. The chemical stability of kaurenoic acid and the antibacterial activity of both the resin and the diterpenoid were studied in microcosms containing plant-associated soil. After 15 days of incubation, the diterpenoid was stable, as determined by 1H nuclear magnetic resonance and thin-layer chromatography, and soil extracts still exhibited antibacterial activity. However, after 30 days of incubation, loss of antibacterial activity of soil extracts correlated with removal or chemical modification of kaurenoic acid. The effect of the resin or this diterpenoid on the soil bacteria community was analyzed by the terminal restriction fragment length polymorphisms technique. After 15 days of incubation, the resin and the pure compound caused significant changes in the soil bacterial community. The relative abundance of specific bacterial groups was differentially affected by the resin components, being the effects with the resin stronger than with the kaurenoic acid. After 30 days of incubation, these changes mostly reverted. These results indicate that a plant resin containing diterpenoid compounds plays a significant role controlling specific groups of microorganisms in the soil associated with the plant.

Anti-Bacterial Agents↗

PubMed2006

Characterization of product capture resin during microbial cultivations.

Various bioactive small molecules produced by microbial cultivation are degraded in the culture broth or may repress the formation of additional product. The inclusion of hydrophobic adsorber resin beads to capture these products in situ and remove them from the culture broth can reduce or prevent this degradation and repression. These product capture beads are often subjected to a dynamic and stressful microenvironment for a long cultivation time, affecting their physical structure and performance. Impact and collision forces can result in the fracturing of these beads into smaller pieces, which are difficult to recover at the end of a cultivation run. Various contaminating compounds may also bind in a non-specific manner to these beads, reducing the binding capacity of the resin for the product of interest (fouling). This study characterizes resin bead binding capacity (to monitor bead fouling), and resin bead volume distributions (to monitor bead fracture) for an XAD-16 adsorber resin used to capture epothilone produced during myxobacterial cultivations. Resin fouling was found to reduce the product binding capacity of the adsorber resin by 25-50%. Additionally, the degree of resin bead fracture was found to be dependent on the cultivation length and the impeller rotation rate. Microbial cultivations and harvesting processes should be designed in such a way to minimize bead fragmentation and fouling during cultivation to maximize the amount of resin and associated product harvested at the end of a run.

Adsorption↗

PubMed1976

Observations on cavity liners for composite resin restorations.

Adhesion or surface roughness and discoloration at the interface between pulpinsulating materials and composite resins were taken as indications for interaction between the resins and the insulating materials. Some interaction occurred between all insulating materials and resins investigated. After separation of the restorative resins, the interaction of Dycal with the different composite resins varied considerably and decreased in the following sequence: Opotow, Natural, and Adaptic. The interactions of ZOE with Natural and with Adaptic were similar and more pronounced than the interaction at the Adaptic-Dycal interface but less pronounced than at the Dycal-Natural interface. A very thin film of Tubulitec was found to adhere to the composite resins in some areas. The adherence of liners containing calcium hydroxide to dentin was found to be generally stronger than the bond between these liners and composite resins. Separation of the composite resins caused tears in the varnishes and frequently in Hydroxyline. Almost completely intact layers of the varnish Copalite were observed on dentin, but Zahnlack apparently dissolved to a great extent in the resins. Among the liners containing calcium hydroxide, Dycal and Tubulitec were found to give rise to a high pH in samples of saliva, but Hydroxyline did not. Porosity and a folded surface were observed for Hydroxyline, indicating the entrapment of the solvent beneath a dry superficial layer.

Adhesiveness↗

PubMed1985

A shear test evaluation of a new, modified, unfilled resin.

A shear test was conducted under simulated oral environmental conditions to examine the retention of a new, commercially available modified unfilled resin in comparison with a conventional unfilled resin provided by the same manufacturer. Within the experimental limits of this study no difference was observed between the retention of the conventional and the modified unfilled resins to enamel specimens. However, for dentin specimens the modified resin was clearly superior to the conventional resin, which gave essentially zero retention. With the recommended procedure, the retention of the modified resin to dentin was 13% of that for the retention of either resin to enamel. It was also observed microscopically that the new resin demonstrated good wetting ability of the dentinal surface. The retention of the two resins to dentin with various surface treatments was determined. The recommended surface preparation procedures of cleaning the dentin surface with hydrogen peroxide followed by a water rinse gave equivalent, if not superior, results to a 1-minute etch with phosphoric acid or citric acid followed by a water rinse.

Acid Etching, Dental↗

PubMed2005

Properties of resorcinol-tannin-formaldehyde copolymer resins prepared from the bark extracts of Taiwan acacia and China fir.

Resorcinol-tannin-formaldehyde copolymer resins (RTF) were prepared by using the bark extracts of Taiwan acacia (Acacia confusa) and China fir (Cunninghamia lanceolata) to substitute part of the resorcinol. From the results, the content of reactive phenolic materials in Taiwan acacia and China fir bark extracts were 51.6% and 46.5%, respectively. Aromatic compounds were the main components in the bark extracts showed by FT-IR analysis. The conventional synthesis condition used for RF resin was certainly not suitable for the RTF copolymer resin. It should be formed the novolak RF prepolymer by reacting the resorcinol with formaldehyde at the first stage, and then the bark extracts added and underwent the copolymerization reaction under acidic condition at the second-stage. The RTF copolymer resins prepared had cold-setting capability. They had higher viscosity, shorter gel time as compared with the RF resin. The RTF copolymer resins could be carried out the gluing application immediately after the hardener was added and had bonding strength the same as RF resin. But the RTF copolymer resins had worse stability and shorter shelf life than RF resin.

Acacia↗

PubMed2004

Retention behavior of C1-C6 aliphatic monoamines on anion-exchange and polymethacrylate resins with heptylamine as eluent.

Retention behavior of C1-C6, aliphatic monoamines (methylamine, ethylamine, propylamine, butylamine, amylamine and hexylamine) on columns (150 mm x 6 mm i.d.) packed with various anion-exchange resins (styrene-divinylbenzene (PS-DVB) copolymer-based strongly basic anion-exchange resin: TSKgel SAX, polymethacrylate-based strongly basic anion-exchange resin: TSKgel SuperQ-5PW and polymethacrylate-based weakly basic anion-exchange resin: TSKgel DEAE-5PW) and unfunctionized polymethacrylate resins (TSKgel G5000PW and TSKgel G3000PWXL) was investigated with basic solutions (sodium hydroxide and heptylamine) as the eluents. Due to strongly electrostatic repulsion (ion-exclusion effect) between these anion-exchange resins and these amines, peak resolution between these amines on these anion-exchange resin columns was unsatisfactory with both sodium hydroxide and heptylamine as the eluents. In contrast, these polymethacrylate resins were successfully applied as the stationary phases for the separation of these C1-C6 amines with heptylamine as eluent, because of both small hydrophobicity and small cation-exchange ability of these resins. Excellent simultaneous separation, highly sensitive conductimetric detection and symmetrical peaks for these C1-C6 amines were achieved on the TSKgel G3000PWXL column in 35 min with 5 mM heptylamine at pH 11.1 as the eluent.

Amines↗

PubMed2005

Metameric effect between resin composite and dentin.

OBJECTIVES: The purpose of this study was to determine the metameric color differences between resin composites and dentin. METHODS: Spectral reflectance and color of five shades of one brand of resin composite were measured according to the CIELAB color scale relative to the standard illuminant D65, A and F2. Average values of human dentin were used as the optical properties of dentin. Color differences (deltaE(ab)*) between resin composite and dentin relative to three illuminants were calculated, and ratio of deltaE(ab)* values by the illuminant (A/D65 and F2/D65) was calculated. Ratios of changes in hue angle of resin composites by illuminant over those of dentin were compared. RESULTS: In curves of spectral reflectance, three of five shades made more than three crossing points with dentin indicating a metameric effect. Color differences between resin composite and dentin was changed when illuminant were changed from daylight (D65) to incandescent light (A) or fluorescent light (F2). Ratios of deltaE(ab)* value between resin composite and dentin by the illuminant were 0.74-0.98. Color difference relative to D65 was larger than those for illuminants A and F2. Differences in hue angle (value relative to illuminant A-that to D65) of resin composites were in the range from -10.1 to -7.2 (-13.8 to -14.0 in dentin), and those between F and D65 were 2.6-5.2 (-3.9 to -2.8 in dentin). SIGNIFICANCE: Changes in optical properties of resin composites relative to the different illuminants were different from those of dentin; therefore this inconsistency should be considered in shade matching of resin composites.

Color↗

PubMed2006

Influence of fluorescent whitening agent on the fluorescent emission of resin composites.

OBJECTIVES: The objective of this study was to determine the fluorescent emission of experimental resin composites after addition of a fluorescent whitening agent in varied concentrations. The effects of thermocycling and composition of resin matrix on the fluorescent emission were also determined. METHODS: An experimental light curing resin matrix was made by mixing Bis-GMA, UDMA and TEGDMA in the ratio of 1:1:1 by weight, and silane coated glass filler was added in the ratio of 50 wt.% of resin composite. A fluorescent whitening agent [FWA, 1,4-double-(benzoxazole-group-2-group)naphthalene] was added with the concentration of 0.01-0.1%. To determine the difference by the resin matrix, two resin composites (60 wt.% Bis-GMA or UDMA with 40 wt.% TEGDMA) with the same filler content were made, and the FWA was added. Five specimens of 2mm in thickness were made for each group. Spectral reflectance was measured relative to the illuminant D65 on a reflection spectrophotometer. From the spectral reflectance values, the difference in reflectance (fluorescence spectra) by the inclusion or exclusion of UV component was calculated. After the baseline measurement, thermocycling was performed for 500 and 1000 cycles, and the fluorescent emission was measured again. RESULTS: The concentration of FWA influenced the fluorescent peak heights and areas (p<0.05), but thermocycling up to 1000 cycles did not influence the values. Fluorescence peak wavelength was not changed by the resin matrix, but peak height and area were influenced by the resin matrix (p<0.05). SIGNIFICANCE: FWA added with the concentrations of 0.01 and 0.05% emitted fluorescence, which was higher than those from commercial resin composites.

Analysis of Variance↗