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At least 145 records · Page 8Linked to original sources
PubMed1996

3-year clinical evaluation of a compomer, a resin-modified glass ionomer and a resin composite in Class III restorations.

PURPOSE: To evaluate and compare intra-individually a polyacid-modified resin composite, commonly called compomer (Dyract), a resin-modified glass ionomer cement (RM GIC)(Fuji II LC) and a resin composite (Pekafill) in Class III cavities. MATERIALS AND METHODS: In 50 patients, 154 Class III restorations were placed. Most patients received one of each of the experimental materials. At baseline, 6 months, 1, 2 and 3 years the restorations were evaluated by slightly modified USPHS criteria. RESULTS: At 3 years, 152 restorations were evaluated. Two restorations were replaced, one due to fracture and one due to secondary caries. The resin composite showed significantly better color match. A slight but still acceptable color shift and increased surface roughness was seen for the RM GIC. The compomer and the resin composite performed significantly better than the RM GIC. No postoperative sensitivity was reported and no loss of vitality was seen after use of the three different total etch techniques.

Adult↗
PubMed1994

Sealant and resin viscosity and their influence on the formation of resin tags.

The ability of resin to penetrate tooth enamel during orthodontic bonding may be affected by the viscosity of the resin and the presence of a sealant. Twenty-four extracted molars were randomly divided into six groups of four. Three resin viscosities were applied with and without sealant and resin tag formation was studied with a scanning electron microscope. Statistically larger resin tags resulted in the group using the more fluid composite resin (orthodontic Concise) in combination with the sealant, although the frequency, regularity and form of the tags did not differ significantly among the various viscosities.

Acid Etching, Dental↗
PubMed1993

A comparison of the shear bond strengths to a resin composite of two conventional and two resin-modified glass polyalkenoate (ionomer) cements.

The inability of resin composite to bond directly to dentine has compromised the clinical success of this restorative material. This problem may be overcome by the so-called laminate technique in which glass polyalkenoate cement is placed upon dentine and then covered with a resin composite. The cement both adheres to dentine and affords micromechanical attachment to the composite. The introduction of the resin-modified glass polyalkenoate cements (RMCs) offers the potential for chemical union between cement and composite. This investigation examined the shear bond strengths of P-50 resin composite to four glass polyalkenoate lining materials, with and without the application of an intermediate bonding agent (Scotchbond 2). Two of the cements were RMCs (Vitrebond, XR-Ionomer) and the others were conventional base materials (Baseline, Ketac-Bond). The bond between P-50 and Vitrebond with or without Scotchbond 2 was significantly (P < 0.01) stronger and more consistent (P < 0.05) than that observed for all other materials. The treatment of the conventional materials and XR-Ionomer with Scotchbond 2 significantly (P < 0.01) improved the bond strengths to P-50. It is concluded that Vitrebond formed the most favourable cement-resin composite bond and that the other materials studied should be used in conjunction with an effective intermediate bonding agent, such as Scotchbond 2.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1995

Effect of unfilled resins and a silane primer on bonding between layers of a light-activated composite resin veneering material.

This investigation evaluated the effect of unfilled resins and a silane primer on bonding between layers of a urethane-based composite resin veneering material. Shear bond strengths between the layers were determined with a two-liquid silane primer and three unfilled resin bonding agents. The silane primers and unfilled resins enhanced the bond between layers of the veneering material. Durability of the bond, however, was influenced by the composition of the bonding agent. Among the systems investigated, combined use of the silane primer with triethyleneglycol dimethacrylate-based unfilled resin exhibited durable and consistent bond strength.

Analysis of Variance↗
PubMed1999

Clinical performance of pressed ceramic inlays luted with resin-modified glass ionomer and autopolymerizing resin composite cements.

STATEMENT OF PROBLEM: Several in vitro studies have been published showing the incapability of the chemical cure of dual-cured resin composite luting agents to compensate for absence of visible light activation. PURPOSE: This study evaluated and compared pairs of Empress ceramic inlays luted with 2 chemical-cured luting agents: a resin-modified glass ionomer cement and a resin composite within individual patients. MATERIAL AND METHODS: Seventy-nine ceramic inlays were placed in class II cavities in 29 patients. In each patient half of the inlays were luted with a resin-modified glass ionomer cement and the other half with a chemical-cured resin composite cement. The inlays were evaluated clinically, according to modified USPHS criteria, at baseline, after 6 months, and 1 and 2 years. RESULTS: No failed inlays were observed during the 2-year follow-up. A slight ditching of the cement margins was observed in both luting groups. No significant difference was seen between the 2 luting techniques. CONCLUSION: IPS Empress inlays luted with both chemical-cured luting agents functioned satisfactorily in the short-term follow-up. Longer observation periods are necessary to evaluate the long-term clinical behavior of both luting techniques.

Adult↗
PubMed1998

Fracture toughness determination of composite resin and dentin/composite resin adhesive interfaces by laboratory testing and finite element models.

OBJECTIVES: The reliability and validity of the adhesive bond toughness of dentin/composite resin interfaces were studied from the standpoint of fracture mechanics. METHODS: The fracture toughness (KIC) and fracture energy (JIC) values of two different composite resins (Brilliant Dentin and P50) were determined by using single edge notch (SEN) specimens loaded in three point bending and the results were analyzed by the t-test method (p < 0.1). The fracture loads of dentin/composite resin interface with different initial crack lengths were obtained experimentally. The adhesive fracture energy (J(adh)), residual fracture energy (J(res)) and effective (total) fracture energy (J(eff)) for the symmetrical bimaterial (SBM) joint specimen for dentin/composite resin interfaces were calculated and the applied fracture energy (J(appl)) values under the mastication force were obtained for the axisymmetric tooth models. All numerical calculations were carried out by the finite element method and software programs were prepared according to fortran 77. RESULTS: The fracture toughness and energy values obtained experimentally for Brilliant Dentin were found to be higher than those for P50. It was seen that, calculated J values (J(adh) and J(res)++) changed with the crack length; but the effective fracture energy (J(eff)++) was independent of the crack length, as expected. The applied fracture energy (J(appl)) and effective fracture energy (J(eff)) are considerably smaller than the experimentally determined JIC values of composite resins. SIGNIFICANCE: The bonded interface tends to produce microscopic flaws which could act as critical stress risers promoting interfacial failures. The initiation and propagation of such flaws under the mastication forces can be followed by fracture toughness (KIC) or fracture energy (JIC) in linear elastic fracture mechanics (LEFM).

Bicuspid↗
PubMed2001

Antibacterial properties of dentin bonding systems, polyacid-modified composite resins and composite resins.

This study examined the antibacterial activities of the bonding systems Syntac, EBS and Scotchbond 1, the polyacid-modified composite resins Hytac and Compoglass, and the composite resins Tetric, Z100 and Scalp-it. They were evaluated using the cariogenic bacteria Streptococcus mutans, Lactobacillus salivarius, Streptococcus sorbinus and Actinomyces viscosus in vitro with a modified cylinder drop plate agar diffusion assay. All adhesives of the dentin bonding systems and the polyacid-modified composite resins exhibited various degrees of antibacterial activity against all of the test bacteria. On the contrary, composite resins did not affect bacterial growth. The data suggest that the use of these adhesives and polyacid-modified composite resins may reduce the consequences of microleakage owing to their antibacterial properties.

Actinomyces viscosus↗
PubMed1999

Effect of two abrasive systems on resin bonding to laboratory-processed indirect resin composite restorations.

PURPOSE: This study compared two methods of surface roughening or preparation, with or without the use of proprietary surface wetting agents, to evaluate their effect on resin cement adhesion to the following laboratory-processed, indirect restorations: Artglass (AG), belleGlass HP (BG), Concept (C), and Targis (T). Methods of surface roughening or preparation included microetching with aluminum oxide (AO): 50 microns at 34 psi and silanized silica coating, CoJet-Sand (CJ): 30 microns at 34 psi. Artglass and Concept were tested with and without the use of their respective surface wetting agents: Artglass Liquid (AGL) and Special Bond II (SB). MATERIALS AND METHODS: One hundred twenty specimens, each consisting of a pair of cylinders (7.0 x 3 mm and 4.3 x 3 mm) were fabricated. The larger cylinder or base was embedded in self-curing resin in a phenolic ring, and bonding surfaces were finished with 320-grit silicon carbide paper. Specimen pairs for each restorative material were randomly assigned to treatment groups (n = 10) and received the following surface treatments prior to cementation: group 1 (AG/AO/+AGL), group 2 (AG/AO/-AGL), group 3 (AG/CJ/+AGL), group 4 (AG/CJ/-AGL), group 5 (BG/AO), group 6 (BG/CJ), group 7 (C/AO/+SB), group 8 (C/AO/-SB), group 9 (C/CJ/+SB), group 10 (C/CJ/-SB), group 11 (T/AO), and group 12 (T/CJ). Specimen pairs were cemented with a dual-cure resin cement (Dual) and a standardized force of 1 MPa. Specimens were light-cured 40 seconds per side (80 s total), then thermocycled 300 times at between 5 degrees and 55 degrees C. Shear bond strengths (MPa) were determined using a Zwick Materials Testing Machine at a crosshead speed of 5 mm per minute. RESULTS: One-way analysis of variance (ANOVA) and Duncan's multiple range test (alpha = 0.05) by restoration type indicated no significant differences in shear bond strength between BG group 5 (29.8 +/- 5.8), BG group 6 (28.3 +/- 4.3), T group 11 (29.3 +/- 4.9), and T group 12 (29.0 +/- 4.4). Shear bond strength in AG group 3 (35.9 +/- 3.4) was significantly higher than in AG group 4 (32.4 +/- 4.0) and equal to that in AG group 2 (31.9 +/- 3.9) and AG group 1 (30.0 +/- 3.6). Shear bond strength in C group 10 (24.8 +/- 5.7) was equal to that in C group 9 (21.5 +/- 2.9), but was higher than in C groups 7 (19.4 +/- 3.1) and 8 (19.3 +/- 3.4). CLINICAL SIGNIFICANCE: Under the conditions of this study, the combination of CoJet-Sand and Artglass Liquid resulted in the highest bond strength for Artglass restorations. Microetching with CoJet-Sand or aluminum oxide followed by wetting with an unfilled adhesive was an effective surface pretreatment for dual-cure resin cementation of the four proprietary indirect resin-ceromer restorations tested.

Acid Etching, Dental↗
PubMed1981

4-META opaque resin--a new resin strongly adhesive to nickel-chromium alloy.

1) A new adhesive opaque resin containing a reactive monomer, 4-methacryloxy-ethyl trimellitate anhydride (4-META), was prepared, and its application to thermosetting acrylic resin veneer crowns was studied. 2) The 4-META opaque resin was applied to a variety of nickel-chromium dental alloy specimens which had undergone different treatment, and endurance tests were conducted to evaluate the durability of adhesion. 3) Stable adhesion against water penetration was achieved with metal surfaces first etched with HCl and then oxidized with HNO3. A bond strength of 250 kg/cm2 was maintained even after immersion in water at 37 degrees C for 30 wk or at 80 degrees C for ten wk. Furthermore, this value did not decrease even after the specimens were subjected to 500 thermal cycles. 4) The 4-META opaque resin studied can eliminate the necessity for retention devices on metal castings. 5) The smooth 4-META opaque resin should have no adverse effects on gingivae.

Acrylates↗
PubMed1990

[Studies on design for resin veneered crowns. 1. Adhesive resin luting agents reinforcement effect].

Resin veneered crowns show several drawbacks which affect the veneering resin: peeling, fracture, falling and also discoloration by leakages from the metal-resin border. The purpose of the present study is to find out a principle of resin veneered crown design allowing the solution of the above-mentioned problems. As a preliminary step, the influence of luting cements on the relative rigidity of veneered crowns and metal frameworks was examined by measuring the strain to static and impact charges on several portions of crowns. The investigation led to the following results: 1. The magnitude of the strain to a static charge increased with the number of shocks but beyond 100 shocks, no variation could be observed. 2. The magnitude of the strain to a static charge was proportional to the weight of the charge. 3. The strain of crowns and metal frameworks set with PanaviaEX had a magnitude smaller than the strain of those set with Fitchecker. 4. The strain to an impact charge had a magnitude 1-4 times larger than the strain to a static charge. 5. The adhesive resin luting agent reinforcement effect could be clearly confirmed.

Crowns↗
PubMedDate not supplied

The use of resin composite pins to improve retention of Class IV resin composite restorations.

This study evaluated the effect of an intracoronal resin composite pin on Class IV resin composite restorations. A control group of 16 bovine teeth was prepared with standardized conventional Class IV preparations. For an experimental group, 16 similar Class IV preparations were made, with the addition of an intracoronal pin channel prepared with a #330 bur into the dentin. All specimens were restored with Herculite XRV and OptiBond according to the manufacturer's recommendations. After one week, specimens were placed in an Instron Universal Testing Machine and loaded at 90 degrees to the long axis until the restorations failed. Results indicated that the mean fracture load of the Class IV restoration group, with the resin composite pin, was 36% higher than the conventional Class IV group (p = 0.02). An intracoronal resin composite pin may aid the retention and resistance form of complex resin composite restorations.

Animals↗
PubMed2004

Hardening of dual-cure resin cements and a resin composite restorative cured with QTH and LED curing units.

OBJECTIVE: The aim of this study was to determine the effects of light intensity and type of light unit (quartztungsten-halogen [QTH] or light-emitting diode [LED]) on the hardening of various resin cements and a resin composite restorative. METHODS: Disk specimens were prepared from 4 dual-cured resin cements (Variolink II, Calibra, Nexus 2 and RelyX ARC). Two QTH light-curing units (Visilux 2, at 550 mW/cm2, and Optilux 501, at 1,360 mW/cm2) and a LED unit (Elipar FreeLight, at 320 mW/cm2) were used for curing. Specimens were light-cured or dual-cured for 10, 30 or 40 seconds with 1 of the 3 light units (curing applied to upper surface only) and were tested 24 hours after curing. Additional cement specimens were self-cured and tested at 15, 30 and 60 minutes and at 24 hours. Testing consisted of measurement of Knoop hardness number (KHN) for each specimen. Six KHN values were obtained for the upper surface only of the various cement specimens in each test group. Disk specimens 2.5 mm thick were also prepared from a resin composite restorative (XRV Herculite). These were light-cured as above, and KHN measurements were obtained for both the upper and the lower surfaces. Mean KHNs were determined, and data were analyzed with analysis of variance. RESULTS: The groups were significantly different (p < 0.05). High-intensity light curing resulted in the highest KHN values for all materials with any of the 3 light-curing times. For the cements, LED light curing (with both dual-curing and light-curing modes) resulted in hardness values similar to those achieved with conventional QTH light curing, although there were some exceptions. However, both LED and conventional QTH light curing resulted in inferior hardening of lower surfaces of the XRV Herculite specimens at the 3 curing times. For all cements except Nexus 2, self-curing resulted in significantly lower hardness values than dual curing. The self-curing mechanism of Variolink II cement needed a longer time to activate than those of the other cements. CONCLUSIONS: High-intensity light curing and longer curing times resulted in the highest KHNs. The LED curing unit was associated with the lowest hardness values for lower surfaces of the resin composite restorative.

Analysis of Variance↗
PubMed2006

Microleakage of Class V resin composites placed using self-etching resins: effect of prior enamel etching.

OBJECTIVE: The purpose of this study was to compare the seal along dentin and enamel margins produced by 3 self-etching resin bonding systems to that of an etch-and-rinse adhesive system. Potential improvement in adaptation along enamel margins through the experimental use of conventional enamel etching prior to application of the self-etching adhesives was also evaluated. METHOD AND MATERIALS: Class V resin composite restorations were placed in prepared cavities in extracted third molars using 3 self-etching dentin adhesive systems: Adper Prompt L-Pop (3M Espe), iBond GI (Heraeus Kulzer), and Tyrian SPE (Bisco), and an etch-and rinse adhesive, Adper ScotchBond Multi-Purpose (3M Espe). A group of teeth also underwent conventional enamel etching prior to use of the self-etching products. The restored teeth were thermocycled, subjected to a dye challenge, and sectioned. The sections were scored using an ordinal leakage scale (n = 20). Ranked data were analyzed using a 2-way analysis of variance and Tukey multiple comparison. RESULTS: When used as directed, there were no significant differences along dentin margins for any of the adhesives, but Adper Prompt and iBond demonstrated significantly greater leakage than the etch-and-rinse product along enamel margins. The incidence of enamel margin leakage decreased significantly for the same 2 products when enamel etching preceded use of the resin. Enamel etching increased the leakage along dentin margins for all 3 self-etching products, but not significantly. CONCLUSION: Considerable improvement of all classes of dentin-adhesive resin systems is still needed. Practitioners should await further clinical trials before adopting use of self-etching resins, especially for large occlusal restorations.

Acrylic Resins↗
PubMed1995

Bonding of resin composites to resin-modified glass ionomers.

PURPOSE: To evaluate the bonding between resin composites and resin-modified glass ionomer restorative materials. MATERIALS AND METHODS: Bar-shaped specimens of Fuji II LC, Photac-Fil, and Vitremer were fabricated in a mold. After application of unfilled resin, resin composite (either Silux Plus or Restorative Z100) was condensed into the mold against the glass ionomer substrate and was light-cured. These bonded specimens, as well as intact specimens of each material, were placed on a three-point bending apparatus and were loaded until failure using a Zwick testing machine. The transverse strength of each specimen was calculated. RESULTS: Mean transverse strengths of bonded specimens ranged from 50% to 78% of the transverse strength of the intact glass ionomer materials. The lowest transverse strength was 18.1 MPa, for Photac-Fil/Z100, and the highest was 29.6 MPa, for Fuji II LC/Silux. Statistical analysis indicated that the type of composite used had no significant effect on transverse strength. However, the type of resin-modified glass ionomer used was significant. Although there was much overlap between materials, bonded specimens made with Fuji II LC had the highest absolute strength, and those made with Photac-Fil had the lowest absolute strength. Bonded Vitremer specimens had the highest transverse strength relative to the cohesive strength of the material.

Analysis of Variance↗
PubMed2004

Systemic induction of traumatic resin ducts and resin flow in Austrian pine by wounding and inoculation with Sphaeropsis sapinea and Diplodia scrobiculata.

The potential role of the resin system in the response of Austrian pine (Pinus nigra Arn.) seedlings to mechanical injury and fungal infection was studied in greenhouse experiments. Anatomical observations were performed on 2-year-old plants wounded at collar level and inoculated with Sphaeropsis sapinea (Fr.: Fr.) Dyko & Sutton in Sutton or Diplodia scrobiculata (J. de Wet, B. Slippers & M. J. Wingfield, sp. nov.; sensu de Wet et al. 2003), two fungal pathogens that cause shoot blight and canker on conifers, and that are characterized by different levels of aggressiveness. Histological examination of host tissue taken from the stem at 0, 8, and 12 cm above the treatment site revealed significant treatment- and time-dependent effects on the course of locally and systemically induced traumatic resin duct (TRD) development. Occurrence of TRDs was observed after 4 days only in seedlings inoculated with D. scrobiculata. At 12 days, TRDs were present also in mock-inoculated controls. No TRDs appeared in seedlings inoculated with S. sapinea. However, S. sapinea caused loss of vacuolar phenolics, severe disruption of cambial tissue and invaded the host xylem quickly and apparently unimpeded, whereas D. scrobiculata was never detected in the host xylem. Five-year-old Austrian pines subjected to the same stem base treatments were used to determine the resin mass flowing from the stem 30 cm above the treatment sites. Wounding and/or inoculation induced a significant, 8.3-fold average increase in systemic resin flow over the untreated trees 3 weeks after basal treatment, suggesting that wounding is the sole prerequisite for systemic induction of resin flow. The results are discussed in the context of current disease resistance models.

Ascomycota↗
PubMed1992

Bonding fixed prosthodontic composite resin and precious metal alloys with the use of a vinyl-thiol primer and an adhesive opaque resin.

Adhesive bonding of a light-cured fixed prosthodontic composite resin joined to silver- and gold-based alloys was investigated with the use of a metal primer and an adhesive opaque resin. The primer contained an adhesive bonding promoter for precious alloys, 6- (4-vinylbenzyl-n-propyl) amino-1, 3, 5-triazine-2, 4-dithiol (VBATDT). The cast metal specimens were alumina-blasted and primed with VBATDT acetone solution. A self-curable 4-META/MMA-TBB opaque resin was used to bond the primed metals and a light-cured composite resin. Prepared specimens were thermocycled in water and bond strengths were determined. The shear bond strengths after 100,000 thermocycles (4 degrees C to 60 degrees C for 1 minute) were 28.4 MPa for Ag-Pd-Cu-Au alloy and 20.8 MPa for type III gold alloy. This simple method may be used to bond silver or gold alloy and light-activated fixed prosthodontic composite resin.

Adhesives↗
PubMed1993

Radiopacity of posterior composite resins, composite resin luting cements, and glass ionomer lining cements.

The radiopacities of seven posterior composite resins, seven composite resin luting cements, and six glass ionomer lining cements were studied. The purpose was to obtain an indication of radiopacity values of different brands within each of these three groups of materials and to show differences in radiopacities of composite resin inlay materials and their accompanying luting cements. On radiographs, the optical densities of standardized samples were determined and radiopacity values of the materials were expressed in millimeter equivalent aluminum. The composite resins observed displayed higher radiopacities than aluminum. A luting cement and a glass ionomer cement were shown to be less radiopaque than aluminum. Generally the radiopacity of composite resins appeared to be higher than their accompanying luting cements. If materials with substantial differences in radiopacity are used in combined applications for the restorative treatment of teeth, lower radiopacity can interfere with the diagnosis of caries and the detection of gaps near the restoration.

Bicuspid↗
PubMed1989

Sealing root canals with low-viscosity resins in vitro: a scanning electron microscopy study of canal cleansing and resin adaption.

Low-viscosity resins of the fissure sealant type have been suggested in the literature as having potential for use as root canal filling materials. A low-viscosity resin may seal a root canal by flowing into clean dentinal tubules after smear layer removal. This investigation with scanning electron microscopy examines the efficacy of two methods of root canal preparation and the effectiveness of different chemicals on smear layer removal. Ultrasonic preparation with 0.25% sodium hypochlorite solution and final agitation with 50% citric acid solution were found to produce a very clean canal wall, free of smear layer in coronal and middle parts. However, low-viscosity resin used in conditions that aimed to simulate in vivo conditions failed to penetrate open dentinal tubules to a significant extent. On the basis of these observations made with scanning electron microscopy, low-viscosity resins would not seem suitable as root canal filling materials, because they are unlikely to form a satisfactory adaption to the canal wall. In addition, if treatment fails, these resins are impossible to remove from a root canal without much destruction of tooth substance.

Citrates↗