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PubMed2002

A modification of the quininium resin test for assessing gastric acidity.

BACKGROUND: Gastric acid is an important defence against enteric infection. Studies investigating the relationship between hypochlorhydria and enteric infections or gastric malignancy have been limited by difficulties in the non-invasive measurement of gastric acidity. AIM: To develop a blood test for hypochlorhydria based on the quininium resin test. METHODS: Quininium resin dissociates to liberate free quinine at pH <or= 3.5. Ten fasting adult volunteers ingested 100 mg/kg of quininium resin twice: once before (control) and once after acid suppression with rabeprazole (10 mg b.d. for 3 days). Blood and serum samples were collected at baseline and 45, 60, 75, 90 and 120 min after ingestion. Quinine levels were measured fluorometrically from 100 microL samples after simple extraction. Results obtained by the quininium resin test were compared with gastric juice pH measurements. RESULTS: After quininium resin ingestion, mean quinine levels were lower in the acid-suppressed than in the control condition at all times (P < 0.001). Optimized cut-off values at 90 min post-ingestion yielded 95% accuracy rates in both serum and blood. Quininium resin was well tolerated. CONCLUSIONS: Using blood or serum, the quininium resin test identifies hypochlorhydria accurately and non-invasively. This test may be useful in screening for gastric atrophy and in studies investigating hypochlorhydria.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1982

Massive digitoxin intoxication. Treatment of Amberlite XAD 4 resin hemoperfusion.

Amberlite XAD 4 resin hemoperfusion was studied in the treatment of massive digitoxin overdosage. In vitro experiments using 4 hour resin hemoperfusion showed that digitoxin is removed 100 percent from an isotonic saline reservoir, 83 +/- 14 percent from plasma, and 42 +/- 7 percent from whole blood. In dogs, serum level reduction is fast: 50 +/- 12 percent in 15 minutes, 71 +/- 6 percent in 180 minutes; mean plasma clearance is 24 +/- 6.5 ml/min for a 150 ml/min plasma flow rate. Eleven patients with massive digitoxin overdosage recovered with resin hemoperfusion. Serum level reduction was 32 +/- 14 percent with a 325 g resin column, 59 +/- 6 percent with two 325 g resin columns in series as compared with a 4.5 +/- 1.7 percent reduction without perfusion. Hemoperfusion increased the rate of spontaneous removal of digitoxin 8.6 +/- 3.3 times with a 325 g resin column, and 14 +/- 7.4 times with two 325 g resin columns.

Adult↗
PubMed2002

[Effect of self-etching primers on microleakage of resin composites in class V restorations]

OBJECTIVE: To evaluate in vitro microleakage of class V restorations using two self-etching primers with a flowable resin or hybrid resins. METHODS: Forty human molars were divided into 3 groups according to axial surfaces. Each group was randomly assigned to 2 subgroups (n=20) with either butt-joint or the beveled preparations. Class V preparations were cut in cemento-enamel junction. Groups A, B, C were respectively restored with CLB2/Clearfil AP-X, APMB/FHC-Merz or APMB/Liquicoat. Half specimens of each subgroup were thermocycled 2 500 times. After staining, dye penetration was evaluated in the ordinal scale at 40Xmagnifications for occlusal and the gingival margins. The wall adaptation of the randomly selected specimens was analyzed with a SEM on replicas of the sectioned teeth. RESULTS: None of bond systems in this study prevented the microleakge. The restorations with the bur-beveled preparations leaked the same as those with the butt joint preparations (P>0.05). The thermocycled specimens and the non-thermocycled specimens leaked similarly (P>0.05). The flowable resin-liqucoat leaked significantly more than hybrid resin in dentinal margins (P<0.05). CONCLUSION: The self-etching primers can not reduce the microleakge in the dentin-restoration interfaces. The flowable resin leak more than the hybrid resin in dentin-restoration interfaces. The bur- beveled preparations do not significantly reduce the microleakage in class V resin restorations bonded with self-etching primers.

Journal Article↗
PubMed2002

[Analysis of infinity optical thickness between nine kinds of composite resins with the same color mark].

OBJECTIVE: This study compared the infinity optical thickness of composite resins with the same color marks. METHODS: In this test nine composite resins (shade A2) were used. A plastic mold (10mm in diameter, 4mm in height) was used to prepare 27 disk specimens. Color was measured by CIE L*a*b* relative to CIE source against a white and a black background, using a colorimeter. Color difference (DeltaE*) was calculated as DeltaE=[(DeltaL*(2)+(Deltaa*)(2)+(Deltab*)(2)](1/2). The heights of composite resins were recorded as DeltaE is approximately 1.5. The infinity optical thickness of composite resins when DeltaE = 1.5 was calculated by regression formulation. RESULTS: The results indicated that composite resins with hybrid filler and opaque pigments were superior infinity optical thickness. Composite resins contain micro-filler were inferior infinity optical thickness. CONCLUSION: Although composite resins with the same color mark had the similar fillers, they had different color and infinity optical thickness.

English Abstract↗
PubMed1999

[The effect of different curing methods on the rate of base resin shrinkage]

OBJECTIVE:On the base of resin characters,the relation between the fit of deture base and curing ways was discussed.METHODS:Four resins and three processing techniques were evaluated in this study to measure the polymerization shrinkage and discuss the effect of different curing methods on base resin shrinkage. The processing techniques were conventional hot water curing method,microwave curing and microwave compression curing method. RESULTS:(1)The processing of hot water curing is long, though the linear shrinkage is the smallest.The shrinkage of each resin differs.It aslo shows great deformability. (2)Microwave curing is faster. Studies indicate that it is easy to produce porosity in the interior of the resin by mononer releasing quickly,and greater shrinkage was observed in polymerization than conventional hot water. (3)Microwave compresion curing method is cleaner and faster too. There's little difference among the resins and this system can produce a more homogeneous deture base and reduce porosity. But it has the greatest shrinkage. CONCLUSION:All of the data revealed that different curing methods have great influence on the shrinkage of base resin composites.

Journal Article↗
PubMed2003

Biological activity of some naturally occurring resins, gums and pigments against in vitro LDL oxidation.

Naturally occurring gums and resins with beneficial pharmaceutical and nutraceutical properties were tested for their possible protective effect against copper-induced LDL oxidation in vitro. Chiosmastic gum (CMG) (Pistacia lentiscus var. Chia resin) was the most effective in protecting human LDL from oxidation. The minimum and maximum doses for the saturation phenomena of inhibition of LDL oxidation were 2.5 mg and 50 mg CMG (75.3% and 99.9%, respectively). The methanol/water extract of CMG was the most effective compared with other solvent combinations. CMG when fractionated in order to determine a structure-activity relationship showed that the total mastic essential oil, collofonium-like residue and acidic fractions of CMG exhibited a high protective activity ranging from 65.0% to 77.8%. The other natural gums and resins (CMG resin 'liquid collection', P. terebinthus var. Chia resin, dammar resin, acacia gum, tragacanth gum, storax gum) also tested as above, showed 27.0%-78.8% of the maximum LDL protection. The other naturally occurring substances, i.e. triterpenes (amyrin, oleanolic acid, ursolic acid, lupeol, 18-a-glycyrrhetinic acid) and hydroxynaphthoquinones (naphthazarin, shikonin and alkannin) showed 53.5%-78.8% and 27.0%-64.1% LDL protective activity, respectively. The combination effects (68.7%-76.2% LDL protection) of ursolic-, oleanolic- and ursodeoxycholic- acids were almost equal to the effect (75.3%) of the CMG extract in comparable doses.

Cholesterol, LDL↗
PubMed1999

In vivo comparison of a microfilled and a hybrid minifilled composite resin in Class III restorations: 2-year follow-up.

An in vivo comparison was made of two different types of restorative resins over a 2-year period: a microfilled resin (-1158262462Silux Plus, 3M-1158262462, USA) and a hybrid minifilled composite resin (-1158262461Herculite XRV, Kerr-1158262461, USA); 56 restorations were placed in 28 patients by one experienced dentist and examined by two independent evaluators using the United States Public Health Service (UPSHS) rating system for marginal adaptation, marginal discoloration, surface roughness, anatomic form and modified criteria for color match (direct and indirect evaluation). Modified criteria divided the classic A score into A1 for "not detectable" filling and A2 for "slightly discernible filling". Restorations were evaluated at baseline, 1 week, 6 months, 1 year and 2 years later. After 2 years, all materials were considered satisfactory for marginal adaptation, anatomic form and surface roughness (no "Charlie", or "Delta" ratings). No recurrent caries was observed. Clinical evaluation showed a significantly higher rate of marginal discoloration for the microfilled composite resin than the other resin. Hybrid composite resin materials may be expected to perform well as an anterior restorative material. Photographic ratings confirmed the clinical evaluation. The modified evaluation for color match demonstrated differences, which are not discernible with the USPHS system and showed, more rapidly, differences that appear later with the USPHS system.

Adolescent↗
PubMed1991

Bond strength and failure analysis of light-cured denture resins bonded to denture teeth.

This study examined the tensile bond strength and failure sites of one heat-cured (Microlon) and two visible light-cured (Triad and Extoral) denture resins to two types of denture teeth. The resins were processed into cylinders against denture teeth milled to the same size. Half of the specimens were thermocycled. After tensile testing, statistical analysis (p 0.05) showed that the strongest bond was achieved with the heat-cured resin Microlon, whereas Triad resin displayed the stronger bond between the two light-cured resins. Scanning electron microscopic analysis showed that the nature and location of the fracture sites was different among the three resins tested.

Acrylic Resins↗
PubMed1993

Measurement of composite resin filler particles by using scanning electron microscopy and digital imaging.

Composite resins are routinely classified on the basis of filler particle size for purposes of research, clinical applications, and communications. The size and characterizations of filler particles have also been considered a significant factor in the rate of wear of composites. Making valid correlations between the filler particles within a composite and wear requires accuracy of filler particle size and characterization. This study was initiated to examine two methods that would (1) qualify the filler particle content of a composite resin and (2) quantify the number, size, and the area occupied by the filler particles in composite resins. Three composite resins, BIS-FIL I, Visio-Fil, and Ful-Fil, were selected as the materials to be examined, on the basis of their published composite classification type as fine particle. The findings demonstrated that scientific methods are available to examine qualitatively and measure quantitatively the composite resin filler particles in terms of their numbers, sizes, and area occupied by use of a scanning electron microscope and digital imaging. Significant differences in the filler particle numbers, sizes, and the area occupied were found for the three composite resins in this study that were classified as fine particle.

Acetone↗
PubMed1995

Resin cure determination by polymerization shrinkage.

OBJECTIVES: This study was designed to develop a methodology that would measure the monomer conversion of dental restorative resins without the use of an infrared spectrometer. METHODS: Specimens were prepared from heat-cured TEGDMA/MMA copolymers consisting of 0, 20, 40, 50, 80, and 100 mol% TEGDMA. The pre- and post-cure volumes of bar-shaped specimens (45 X 7 X 1 mm) and thin films were measured. The cure of the thin specimens was determined using changes in resin volume as well as by an infrared spectroscopic method. The cure of thin specimens of a commercially available unfilled bonding resin was also determined using the shrinkage method and by conventional infrared spectroscopic methods. RESULTS: There was no difference (p=0.0617) between cure values of the commercial resin using either conventional IR methods or the shrinkage methods. For each copolymer combination of thin films, there was also no significant difference in the extent of cure between the IR method used and the shrinkage method presented (lowest p-value 9.29). The cure of TEGDMA/MMA copolymer bar specimens demonstrated a decreasing trend of cure with increasing proportion of TEGDMA, and had cure values which were similar to others reported in the literature. SIGNIFICANCE: The evidence from this study demonstrated that the specimen volume method can be used to determine the extent of resin cure of thin film or bulk resin specimens. This method represents an easily performed procedure that can be used by all investigators without expensive equipment.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1995

Bacterial adhesion to dental amalgam and three resin composites.

OBJECTIVES: The ability of three oral bacteria to adhere to hydrophobic amalgam (water contact angle 60 degrees) and hydrophobic resin composites (Prisma-AP.H 56 degrees. Herculite XRV 82 degrees and Z100 89 degrees) was compared using an in vitro assay. METHODS AND RESULTS: Following preincubation of the materials with human saliva, X-ray photoelectron spectroscopy showed the surfaces to adsorb carbon and nitrogen-containing compounds in a conditioning film that appeared to block the detection of Na and others in 2100 resin. Hg and Ag in amalgam, Si and Zn in Prisma AP.H resin and Ag and Na in Herculite resin. The precoating of the substrata by a proteinaceous conditioning film led to decreased binding of viable cells of Streptococcus sanguis CH3, Streptococcus salivarius HB and Actinomyces viscosus WG as compared with the adhesion to bare composites. With and without salivary coating, there was a correlation between increased bacterial hydrophobicity and increased retention on the substrata. However, there was no statistical difference in binding to the amalgam compared with the resin composites. In vitro studies showed that the bacteria autoaggregated in the presence of saliva. CONCLUSION: The results indicate the potential ability of normal oral flora to colonize resin composite.

Actinomyces viscosus↗
PubMed2004

Durability of the resin bond strength to the alumina ceramic Procera.

OBJECTIVES: The purpose of this in vitro study was to evaluate the tensile bond strength of adhesive bonding systems to the densely sintered alumina ceramic Procera, and its durability. METHODS: Plexiglas tubes filled with composite resin were bonded to Procera ceramic discs (99% Al2O3), which were either in their original state as supplied by the manufacturer or which were sandblasted for surface conditioning. Groups of 20 specimens were bonded in an alignment apparatus using 10 bonding methods. Subgroups of 10 bonded specimens were tested for tensile strength following storage in distilled water at 37 degrees C either for 3 days or for 150 days. In addition, the 150 days specimens were thermal cycled 37,500 times. The statistical analyses were conducted with the Kruskal-Wallis test followed by multiple pair-wise comparison of groups using the Wilcoxon rank sum test. RESULTS: Not sandblasted groups showed relatively poor initial bond strengths independent from bonding resins. During 150 days storage time all specimens in the not sandblasted groups debonded spontaneously. Moderate to relatively high initial bond strengths between 18 and 39 MPa were achieved to sandblasted specimens by using the PMMA luting resin Superbond C & B or the composite resin Variolink II or by silica coating and silanation in combination with Variolink II. However, in these groups after 150 days storage time the bond strength decreased significantly. The phosphate monomer containing composite resin Panavia 21 showed the highest bond strength to sandblasted Procera ceramic which did not decrease significantly over storage time. In addition, the bond strengths of sandblasted groups bonded with Variolink II after priming the ceramic with Alloy Primer or the silane Monobond S were relatively high and did also not decrease significantly after 150 days storage time. SIGNIFICANCE: Using ten bonding systems, a stable resin bond to Procera ceramic could be achieved after sandblasting and by using Panavia 21 or by using Variolink II after priming the ceramic with Alloy Primer or Monobond S.

Boron Compounds↗
PubMed2004

Effects of flowable resin on bond strength and gap formation in Class I restorations.

OBJECTIVES: This study measured resin/dentin bond strengths and evaluated gap formation at the pulpal floor of occlusal composite restorations using a flowable resin as a liner with either bulk or incremental placement of the restorative composite. METHODS: Class I occlusal preparations were made in 16 extracted molars, and were randomly divided into two groups for restoration using either One-Step adhesive (OS, BISCO) and Renew composite (RW, BISCO) or OptiBond SOLO adhesive (SOLO, Kerr) and Herculite XRV composite (XRV, Kerr). A flowable resin [AEliteFlo (AE, BISCO) or Revolution (RV, Kerr)] was applied as a liner in half of the specimens of each group. The lined and unlined groups were restored with composite cured in bulk, or cured in 1.5 mm increments. After 24 h in water, the teeth were sectioned into 0.7-mm thick slabs and were examined with an optical microscope (400 x) to determine the presence of internal resin-dentin gaps. The gap-free specimens were trimmed and were subjected to microtensile bond strength testing. Specimens that contained gaps had Knoop hardness of the restorative material measured. RESULTS: All incrementally filled restorations were well adapted to the pulpal floor but nearly all bulk-cured specimens had gaps between the flowable and the hybrid composites. The use of a flowable resin increased the bond strength of OS, but not SOLO. SIGNIFICANCE: The incremental technique prevented gap formation regardless of the use of a flowable resin. In contrast, the use of a flowable composite did not guarantee gap-free restorations or improved bond strength of resin to dentin in bulk-filled restorations.

Barium Compounds↗
PubMed2005

Micro-tensile bond strength of three luting resins to human regional dentin.

OBJECTIVES: To evaluate the micro-tensile bonding strength (muTBS) of three luting resins to human regional dentin. METHODS: Dentin disks from non-carious third molars were prepared from different regions (s, superficial dentin; d, deep dentin; c, cervical dentin), and divided into groups based on anatomical locations and luting resins (Super-Bond C&B: SB; Panavia F 2.0: PF; RelyX Unicem: RU): SB-s, SB-d, SB-c; PF-s, PF-d, PF-c; RU-s, RU-d, RU-c. Luting resins were used according to the manufacturers' instructions, to bond 1-mm-diameter PMMA or composite rods to the exposed dentin specimens under a load of 7.5 N, in the self-curing mode. After storage for 1 or 3 days, muTBS was tested at a cross-head speed of 1mm/min. Data were analyzed with ANOVA and Fisher's PLSD test. The bonding interface and fractography analyses were performed with SEM and TEM. RESULTS: ANOVA results showed that muTBS to superficial dentin was significantly higher than to deep or cervical dentin for all three luting resins. SB-s and PF-s, with the highest muTBS, failed primarily cohesively in luting resin. muTBS of SB-d and SB-c were significantly higher than those of PF and RU. RU, with the lowest regional muTBS, failed mostly within demineralized dentin. SEM and TEM showed that adhesive failures in SB and PF occurred at the top of the hybrid layer (HL), but no obvious HL was observed in RU. SIGNIFICANCE: Luting resins with different chemical formulations and applications yield significantly different bond strengths to different regions in human dentin.

Adolescent↗
PubMed2006

A comparison of fatigue crack growth in resin composite, dentin and the interface.

OBJECTIVES: The objective of this in vitro study was to evaluate the fatigue crack growth properties of the dentin/resin adhesive interface. METHODS: Compact tension (CT) specimens were prepared from coronal dentin, resin composite, and dentin bonded to resin composite using Optibond Solo Plus adhesive. All specimens were then subjected to cyclic Mode I loading while fully hydrated at a stress ratio of R=0.1 and frequency of 5 Hz. Steady state fatigue crack growth was modeled using the Paris Law in terms of the exponent (m) and coefficient (C). RESULTS: The average fatigue crack growth rates in the resin composite ranged from 1.6E-06 to 3.8E-05 mm/cycle with growth occurring over a stress intensity range from 0.40 to 0.77 MPa m(1/2); the average growth exponent was 6.9+/-3.1. Average fatigue crack growth rates for the dentin/resin interface specimens ranged from 5.5E-07 to 6.4E-03 mm/cycle with growth occurring over a stress intensity range from 0.37 to 0.64 MPa m(1/2). The Paris Law exponent for these specimens ranged from 16<or=m<or=25. Fatigue crack growth at the interface occurred primarily in the adhesive resin and at the adhesive-dentin interface. In addition, many of the dentin/resin specimens underwent unstable fracture at a comparatively low stress intensity range without undergoing cyclic crack growth. SIGNIFICANCE: The dentin/resin adhesive interface proved to be significantly more sensitive to fatigue crack growth than either dentin or resin composite. Variation in the cyclic crack growth responses of the dentin/resin interface specimens suggests that the interface, and particularly the adhesive resin, exhibits lower resistance to crack initiation and growth in comparison to dentin.

Adult↗
PubMed2007

Analysis of camphorquinone in composite resins as a function of shade.

OBJECTIVE: To identify and quantify the camphorquinone (CQ) used in different brands of composite resins as a function of the shade analyzed. MATERIALS AND METHODS: Filtek Z250 A3 (FZA3), Filtek Z-250 Incisal (FZI), Pyramid Enamel A1 (PEA1), Pyramid Enamel Translucent (PET), Filtek Supreme A3E (FSA3) and Filtek Supreme GT (FSGT) were used. Five hundred milligrams of each resin were weighed and then dissolved in 1.0 ml of methanol. The samples were centrifuged to accelerate the sedimentation of the inorganic particles. 0.8 ml of the supernatant solution was collected with a pipette and assessed under gas chromatography coupled to the mass spectrometer (GC-MS). The results were compared to pure CQ solutions, used as a standard. Student's t-test, (p=0.05) significant at the level of 5%, compared the results of each brand shade. RESULTS: A smaller amount of camphorquinone was found in Filtek Z-250 (FZI) resin incisal shade when compared to (FZA3) A3 shade. On the other hand, Filtek Supreme resin featured a statistically larger camphorquinone amount in the incisal shade. In Pyramid Enamel resin camphorquinone was found only in shade A1, while the photoinitiator used in the Translucent shade was not identified. SIGNIFICANCE: Based on the data obtained, it is possible to conclude that a single composite resin brand may feature differences in amount and type of photoinitiator used.

Acrylic Resins↗
PubMed2005

Comparison of two video-imaging instruments for measuring volumetric shrinkage of dental resin composites.

OBJECTIVES: The purpose of this study was to measure the polymerization shrinkage of three dental resin composites using two commercially available video-imaging devices to determine if the devices produced equivalent results. METHODS: Small, semi-spherical specimens of a microhybrid (Venus), microfill (Filtek A110), and flowable (Esthet*X Flow) resin composite were manually formed and light activated for 40s using a light-curing unit. The volumetric polymerization shrinkage of fifteen specimens of each brand of resin composite was measured using the AcuVol and the Drop Shape Analysis System model DSA10 Mk2 (DSAS) video-imaging devices. Mean volumetric shrinkage values were calculated for each resin composite and equivalence was evaluated using the two one-sided tests approach. Differences between the means that were less than approximately 5% of the observed shrinkage were considered indicative of clinical equivalence. RESULTS: Mean volumetric shrinkage values measured for the resin composites were: Venus (AcuVol, 3.07+/-0.07%; DSAS, 2.90+/-0.07%); Filtek A110 (AcuVol, 2.26+/-0.10%; DSAS, 2.25+/-0.09%); and Esthet*X Flow (AcuVol, 5.01+/-0.17%; DSAS, 5.14+/-0.11%). Statistical analysis revealed that the two imaging devices produced equivalent results for Filtek A110 and Esthet*X Flow but not for Venus. CONCLUSIONS: Video-imaging systems provide an easy method for measuring volumetric shrinkage of resin composites. As with other methods for measuring volumetric shrinkage, however, they are best used to comparatively measure different materials within the same laboratory.

Acrylic Resins↗
PubMed2005

Shear bond strength of veneering composite resin to titanium nitride coating alloy deposited by radiofrequency sputtering.

OBJECTIVE: The success of dental restorations utilizing composite resin over cast alloy has been variable and affected by micro-leakage. The purpose of this study was to investigate the shear bond strength between a composite resin and cast dental alloy coated with a layer of titanium nitride (TiN). METHODS: Cast disk specimens made of Au-Pd-Ag alloy were randomly divided into four groups. The first group was left uncoated as a control while one group was coated with a metal conditioner, and the other two were coated with TiN at either 200 or 500 W with a radiofrequency magnetron sputtering system. Each group was then bonded to one of two types of light-activated composite resin material. Shear bond strengths were tested and compared for each specimen. The bond strength of each group was analyzed by 2-way ANOVA and by post hoc multiple comparison tests (Fisher's PLSD). RESULTS: As the interaction among groups was not significant (p=0.27) by 2-way ANOVA, TiN coated groups were found to have improved shear bond strength compared with non-coated groups without metal conditioner for both resin composite materials by multiple comparison tests. Furthermore, TiN coating is significantly stronger than non-coated groups with metal conditioner for one of the two resin composite materials examined (p<0.01). CONCLUSIONS: The results suggested that metal surface modification by coated TiN represents a technique that may significantly improve the bond between the Au-Pd-Ag alloy and veneering resin composite.

Acrylic Resins↗