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PubMed1983

Resin-process methods for improved isolation of organisms from blood and other body fluids.

Two resin-based processes and conventional culturing methods were compared in isolating organisms from blood specimens of patients given antimicrobial agents. Of 20 patients whose specimens were found to contain clinically relevant organisms, one or both of the resin-process methods isolated organisms in eight after conventional culturing was unsuccessful. Conventional cultures were successful in five cases in which the resin-process methods did not work, and both resin-process and conventional culturing were successful in seven cases. In eight cases in which other body fluids were cultured, only a resin-process method was successful in four, although they are intended for use only with blood specimens. Data indicate that resin-process methods should be used along with conventional culturing methods when patients have already been given an antimicrobial. A review of the literature shows that the devices improve the recovery of organisms but does not establish that detection time is decreased.

Bacteria↗

PubMed1987

Hypertriglyceridemia: a contraindication to the use of bile acid binding resins.

Bile acid binding resins are indicated for treatment of elevated plasma low-density lipoprotein cholesterol concentrations. In normoglyceridemic patients, plasma concentrations of low-density lipoprotein cholesterol and total cholesterol are closely linked, and for this reason resin treatment of elevated total cholesterol levels in these patients is rational and warranted. Hypertriglyceridemic patients may also have elevated total cholesterol concentrations, and several such patients have been treated with resin. However, resin therapy in these patients is hazardous, since the elevated cholesterol level mainly results from increased plasma concentrations of very-low-density lipoproteins or chylomicrons rather than low-density lipoproteins. In these patients, resin treatment has either no effect or an adverse effect on plasma triglyceride and cholesterol concentrations. The data presented show that fewer than 5 percent of patients whose total plasma triglyceride concentration exceeded 500 mg/dl had elevated low-density lipoprotein cholesterol concentrations, irrespective of total plasma cholesterol concentrations, and no patient whose plasma triglyceride concentration exceeded 1,000 mg/dl had elevated low-density lipoprotein cholesterol levels. Treatment with bile acid binding resins in hypercholesterolemic patients is contraindicated in the presence of hypertriglyceridemia.

Cholesterol↗

PubMed1979

Effect of composite resin bond agent on microleakage and bond strength.

A study was conducted to evaluate the efficacy of the bonding agents supplied with three composite resins in improving the sealing ability of the materials to tooth structure and the bond of the resins to enamel. When the enamel was not etched prior to insertion of the resin, the use of the bonding agents did not improve marginal seal. Little or no marginal leakage was detected when the restorations were placed by means of the acid etch technique, either with or without use of the respective bonding agents. A slight improvement in the bond of the resins to unetched enamel was secured by use of the bonding agents; however, this advantage was lost when the specimens were thermal cycled. Acid etching of the enamel significantly improved the bond of the strength of all three resins, both when the specimens were thermal-cycled and when stored at a constant temperature. Only one of the commercial bond agents enhanced the bond of its respective composite resin to etched enamel subjected to cycling.

Acid Etching, Dental↗

PubMed1982

Conventional and microfilled composite resins. Part II. Chip fractures.

Dentists are accustomed to advantages and disadvantages in the materials at their disposal. This article was concerned with one disadvantage of microfilled composite resins, namely, chip fractures. Probably due to their higher coefficient of thermal expansion, higher water sorption, higher polymerization shrinkage, and lower tensile strengths, cohesive as well as adhesive chip fractures occur three to four times more often with microfilled composite resins than with conventional composite resins. Microfilled composite resins are indicated for esthetic purposes. They are contraindicated for Class IV and stress-bearing restorations. They are indicated for limited use in Class I restorations where esthetics is of primary importance. The technique of use must include acid-etching and intermediate bonding. The microfilled composite resins enjoy a smooth finish and high luster. This offers advantages in areas where smoothness is paramount. They may replace conventional composite resins for resurfacing existing restorations and veneering stained or mottled anterior teeth. They are indicated for treatment of cervical erosion.

Chemical Phenomena↗

PubMed1983

Porosity in boilable acrylic resin.

An acrylic resin developed to be processed by boiling for 20 minutes in water was compared to a conventional heat-processed acrylic resin for porosity when processed according to the manufacturer's directions. No porosity was found in the conventional resin in thicknesses up to 19.5 mm. The boilable resin developed porosity in thicknesses of 6 mm and greater. The porosity increased with increased thickness. The boilable resins should not be used for long-term prostheses or those requiring a thickness of acrylic resin that approaches 6 mm.

Acrylic Resins↗

PubMed1987

Dimensional stability of dentures processed in boilable acrylic resins: a comparative study.

An investigation was conducted to evaluate and compare the dimensional stability of three fast boilable denture resins with a conventional and a high-impact denture resin processed with a long-curing cycle. Although the boilable denture resins have been introduced to the dental profession and offer merits such as faster processing, saving time for the dentist, patient, and technician, reduction of energy costs, and dramatic increase in denture laboratory production without adding personnel or purchasing new equipment, the relevant dental literature is sparse. The results of this investigation indicate that all five denture resins produced dentures that shrink. Also measurements between certain teeth showed shrinkages. Linear shrinkages of denture bases and teeth distances were less than 1%. Flange-to-flange and molar-to-molar changes were less than 0.5 mm and 0.2 mm respectively. Maxillary complete dentures processed in boilable resins presented less distortion in the midpalatal area across the posterior section than dentures processed in the conventional heat-cured resin. Although linear changes reported in this investigation were thought to be clinically insignificant, clinical studies should be conducted to establish correlation with laboratory findings.

Acrylic Resins↗

PubMed1989

The effect of glutaraldehyde base disinfectants on denture base resins.

The effect of two alkaline glutaraldehyde base disinfectants on a heat-cured denture base resin was evaluated by the flexural strength, the repair flexural strength, and the surface morphology of the material that had been immersed up to 12 hours in the disinfecting solutions. The flexural strength of the material was not significantly affected by either disinfectant. The disinfectant with phenolic buffer caused surface pitting of the material after 10 minutes of immersion, and softening and swelling of the surface after 2 hours of immersion. No apparent surface change was observed with the regular alkaline formulation, however. Between the two repair resins, the autopolymerized resin yielded greater repair flexural strength than the light-cured repair resin. However, the repair flexural strength of autopolymerized resin seemed to be influenced by either disinfecting solution whereas the light-cured repair resin was not affected.

Acrylic Resins↗

PubMed1989

An evaluation of the film thickness of resin luting agents.

Acid-etched cast metal resin-bonded retainers require resin luting agents with film thicknesses similar to dental cements to allow complete seating of frameworks without the need for post-bonding adjustments. Conventional cements, restorative resins, and resin cements were compared in terms of film thickness by using the American Dental Association Specification No. 8 for zinc phosphate cement. Most of the resin luting agents had film thicknesses of 20 to 40 microns. Working time was seen to affect film thickness. The particle size of one resin was also examined under scanning electron micrograph.

Dental Cements↗

PubMed1991

The effect of carbon graphite fiber reinforcement on the strength of provisional crown and fixed partial denture resins.

This study compared the moduli of elasticity of three provisional crown and fixed partial denture resins. Eighteen specimens of each resin were reinforced with carbon graphite fibers and 18 resin specimens from each group contained no fibers. Six specimens of each resin, with and without fibers, were tested within 6 hours of fabrication, after 30 days, and after 60 days of water storage. The mean moduli of elasticity of all the resins increased significantly with fiber incorporation. Water storage did not have a significant effect on the moduli of elasticity of the resins tested.

Acrylic Resins↗

PubMed1991

Dimensional changes of processed denture bases after relining with three resins.

This study compared the dimensional change of simulated processed denture bases after relining with three resins. Thirty simulated denture bases 1.5 to 2 mm thick were processed from Lucitone 199 resin following the manufacturer's instructions using the long-cure method. Ten bases were relined with Lucitone 199 (long-cure), 10 were relined with Triad resin, and 10 were relined with Accelar 20 resin. The relined bases were processed on a metal die using a reline jig, and three measurements (from distobuccal flange to distobuccal flange) were made with a traveling microscope immediately before and after relining. Each relined simulated denture base showed a significant dimensional shrinkage after processing. The mean dimensional change values of the Triad resin relined bases were significantly greater than those of the other two resin relined bases. All of the dimensional change values, however, would probably be insignificant in a clinical situation.

Acrylic Resins↗

PubMed1992

Indications for self-cured and light-cured adhesive composite resins.

Self-cured and light-cured adhesive composite resins have biologic advantages and disadvantages. In contrast to the self-cured composite resin, the light-cured composite resin has a greater tendency to separate from a cavity wall and gingival margin. Alternative methods of insertion such as the incremental technique and cement liner have decreased the tendency to separate, but have failed to completely eliminate the problem. The light-cured composite resin may also fracture the marginal enamel rods. The light-cured composite resin is indicated for shallow facial restorations and veneers. The self-cured composite resin is indicated to restore deeper cavities, those with a dentinal gingival margin, and for occlusal restorations.

Adhesives↗

PubMed1992

Linear dimensional variability of three denture base resins after processing and in water storage.

It has been shown that denture base resins shrink during curing and expand during storage in water. This investigation measured and compared linear dimensional changes of three denture base resins that occurred during processing and after storage in water for 30, 60, and 90 days. Triad, Accelar 20, and Lucitone 199 long- and short-cured resins were studied, and it was found that Accelar 20 resin exhibited the least curing shrinkage and Lucitone 199 resin short-cured exhibited the most. However, no significant differences occurred between the groups. After 90 days of water storage, the only resin that exhibited a shrinkage from the processed state was Accelar 20. All of the expansion or shrinkage changes were so small that they were not statistically significant and should not be clinically detectable.

Acrylic Resins↗

PubMed1990

Leachability of denture-base acrylic resins in artificial saliva.

We studied the influence of salivary acidity on leachability of denture-base acrylic resins with etiological interest in denture stomatitis because denture surfaces are frequently exposed to acidic conditions in the oral cavities. Auto-, heat-, and microwave-polymerized resins were immersed in artificial saliva with pH ranging from 4.0 to 6.8 at 37 degrees C, and leachables were pursued quantitatively with time. Methyl methacrylate, methacrylic acid, and benzoic acid leached from all resins. Their concentrations in the saliva were markedly high for auto-polymerized resins, while leachability of heat- and microwave-polymerized resins was so low that quantitative analysis of leachables was impossible. Lower pH showed higher concentrations of methyl methacrylate, although no apparent association was confirmed between salivary acidity and its own leachability. The concentrations of methacrylic acid increased remarkably with an increase in pH, which was probably due to hydrolysis of methyl methacrylate. These results suggest that chemotoxic actions of auto-polymerized resins are potentially ascribable to methyl methacrylate under more acidic conditions and to methacrylic acid under less acidic conditions.

Acrylic Resins↗

PubMed1992

A comparison of monomer conversion and inorganic filler content in visible light-cured denture resins.

Visible light-cured (VLC) denture resins are relatively new products used for the reline and repair of dentures. The conversion of monomer into polymer in 3 brands of visible light-cured denture resins was investigated. The relationship of the inorganic filler content to this conversion was also studied. It was determined that these reline materials vary in monomer conversion and weight percentage of filler, and this variation is brand dependent. The monomer conversion ranged from 77% to 97%. Significant differences in these values were found when duration of light exposure was increased. In addition, resin nearest to the light source polymerized to a greater extent when compared to resin that was 1 mm deep to this surface, hence furthest from the light source. The inorganic filler content ranged from 0% to 15%. For the resin systems studied, the relationship between monomer conversion and inorganic filler loading was inversely proportional. Results indicated that monomer conversion of VLC repair resins was affected by the duration of light exposure as well as the amount of inorganic filler present in the material.

Acrylic Resins↗

PubMed1984

Comparison of surface layer properties of composite resins by ESCA, SEM and X-ray diffractometry.

Hyperfine surface layer properties of three types of dental composite resins, highly-filled, conventional, and micro-filled resins, were studied using X-ray photoelectron spectroscopy (ESCA) by a combination of X-ray diffractometry and scanning electron microscopy (SEM). X-ray diffraction and SEM analysis showed clearly that each resin has different characteristics of SiO2 particle size and distribution. ESCA depth resolution with argon ion etching indicated that, in contrast to conventional and microfilled resins, carbon due to polymers of highly-filled resin decreases dramatically with increasing depth in the nanometer range of the resin-rich surface layer.

Composite Resins↗

PubMed1996

Resin-modified glass ionomer cements: a comparison of water sorption characteristics.

The purpose of this study was to quantify and compare the amount of water absorbed by six commercially available resin-modified glass ionomer cements and to investigate the possible influence of time and resin content on water sorption. The materials evaluated included Variglass used as a restoration, base and liner; Fuji II LC; Fuji Liner; Vitrebond; Vitremer and Photac-Bond. Z100, a composite resin, was used as control. All specimens were manipulated according to manufacturers' instructions and then subjected to a water sorption test based on the ISO 4049 requirements. Storage in water was further extended to 1 month to evaluate the effects of time and indirectly cement maturity on water sorption. Data were subjected to one-way ANOVA and Duncan's test at 0.05 significance level. Results show that the composite resin control had significantly less water sorption than all the resin-modified polyalkenoate cements evaluated. Variglass when used as a base or restorative had the least water sorption after both 1 week and 1 month storage in water. The degree of water sorption was product dependent and appeared to be influenced by the resin (HEMA) content. The results also reflect a potential relationship between time (cement maturity) and water sorption.

Absorption↗

PubMed1993

Bond strength of resin to dentin treated with calcium phosphate desensitizer.

In a previous study we proposed a new method utilizing immediate precipitation of calcium phosphate (CaP) in situ for treatment of dentin hypersensitivity. Sequential application of 5% disodium phosphate followed by 10% calcium chloride on patent dentin surface resulted in instant occlusion of dentin tubules and immediate relief from the hypersensitivity. To guarantee long-lasting effectiveness of the CaP treatment, resin coverage of the treated dentin surface will be the next practical approach. However, the CaP covering the surface may possibly affect bonding of resins. This study determined the effect of the CaP treatment on tensile bond strength of adhesive resins to dentin. Independent of the type of resin used, a bond strength of 4-5 MPa was obtained; cohesive failure occurred within the resin-CaP hybridized composite layer rather than at the dentin surface. The CaP treatment produced a significant increase in the bond strength of one resin.

Animals↗

PubMed1996

The clinical performance of cantilevered resin-bonded bridgework.

OBJECTIVES: The technique of resin-bonded bridgework is a well-accepted clinical technique to replace missing teeth. This study assesses the clinical performance of cantilevered resin-bonded bridgework provided in a university teaching hospital environment. METHODS: One-hundred and twelve patients who had a total of 142 cantilevered bridges were either examined or completed a questionnaire regarding their bridgework. The following data were recorded for each resin-bonded bridge: gender of patient, age at bridge cementation, date of initial cementation, tooth replaced, abutment(s) involved, and grade of clinician responsible for the provision of the bridge. Details of the incidence of debonding with date(s) and the subsequent treatment in relation to the debonded resin-bonded bridge were recorded. The subjects examined indicated their degree of satisfaction with their bridgework on a visual analogue scale. RESULTS: There were 112 patients with a total of 142 bridges, 116 (82%) maxillary and 26 (18%) mandibular. The mean length of clinical service was 36.2 months (s.d. 17.2 months). Only single pontics were included in the bridges, with almost half (49%) replacing a lateral incisor. Of the cantilever resin-bonded bridges studied, 88% remained bonded over the period of the study. A success rate of 94% is reported. CONCLUSION: This study confirms the clinical success of cantilever resin-bonded bridges particularly in the replacement of maxillary lateral incisors, maxillary premolar and permanent mandibular teeth.

Adult↗