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PubMed2002

Evaluation of compatibility between different types of adhesives and dual-cured resin cement.

PURPOSE: The objective of this in vitro study was to evaluate the bonding compatibility between different adhesives and a dual-cured resin cement, using a conventional tensile bond test. MATERIALS AND METHODS: The adhesives used were: Prime & Bond (PB) (Dentsply) (PB), Scotchbond Multi Purpose (SB) (3M), and the activator Self Cure (SC) (Dentsply). The dual-curing resin cement used was Enforce (EF) (Dentsply). Six groups with five specimens in each were tested: G1: EF/PB/EF (light cured); G2: EF/SB/EF (light cured); G3: EF/PB+SC/EF (light cured); G4: EF/PB+SC/EF (only chemically cured); G5: EF/EF (light cured); G6: EF/EF (only chemically cured). The resin cement was applied in two stainless steel molds with a cone-shaped perforation measuring 4 mm in diameter and 1 mm in thickness, and the adhesive was applied between them. Ten minutes after specimens were cured, the tensile strength was measured in a universal testing machine at a crosshead speed of 0.5 mm/min. RESULTS: The mean values (MPa) +/- SD obtained in each experimental group were: G1: 1.4 +/- 0.2; G2: 1.3 +/- 0.2; G3: 1.2 +/- 0.4; G4: 0.8 +/- 0.2; G5: 1.2 +/- 0.1; G6: 0.7 +/- 0.1. The results were statistically evaluated using nonparametric Kruskal-Wallis and Dunn tests (p < or = 0.05). Statistically significant differences among groups were found only between G1 and G4, and G1 and G6. CONCLUSION: There was no incompatibility among the different adhesives used with dual-cured resin cement. The lowest tensile bond strength values occurred in the absence of photoactivation.

Acetone↗

PubMedDate not supplied

The effect of a mouthrinse containing essential oils on dental restorative materials.

Mouthrinses that contain essential oils are effective for controlling plaque and periodontal disease. Recent studies have shown that such mouthrinses are effective at preventing the formation of biofilm in dental unit waterlines. However, there is no information in the literature regarding the effect of such mouthrinses on restorative materials used within the oral cavity. Specimens of three common restorative materials (a glass ionomer, a composite resin, and amalgam) were subjected to continuous exposure to Listerine and distilled water for 10 days; at that time, the strength, fluid sorption, and surface appearance of the specimens were compared. Specimens of the test materials also were placed in intraoral devices; volunteer patients wore these devices for 12 hours per day for a period of 10 days. During that time, the patients were instructed to rinse twice daily for 30 seconds with Listerine Cool Mint or a non-active mouthrinse. After 10 days, the specimens were salvaged from the devices and inspected by visible and SEM examination. This study indicates that routine use of mouthrinses containing essential oils (or even prolonged exposure to such mouthrinses) has no adverse effects on restorative materials that might be expected to react to such mixtures because of their chemical compositions. It was concluded that active mouthrinses do not appear to have any adverse effects on a variety of restorative biomaterials.

Absorption↗

PubMed2000

The comparative radiopacity of Fuji IX-GP, an intermediate restorative material.

The radiopacity of intermediate restorative materials should be sufficient to enable the clinician to distinguish the material from normal and decalcified tooth structure. The purpose of this study was to determine the relative radiopacities of intermediate restorative materials, including a newly introduced high-viscosity, self-cured, condensable glass ionomer material. Radiographs were made of six intermediate restorative materials: two reinforced zinc oxide-eugenol materials (IRM and Zinroc), a conventional glass ionomer material (Ketac-fil), a synthetic resin material (Cavit), a eugenol-free zinc oxide material (Tempit), and a new, general-purpose, condensable glass ionomer material (Fuji IX-GP). Optical density was measured using a densitometer. The optical density of dentin and enamel were used for radiographic comparison. Statistical analysis revealed significant differences among materials: Cavit = IRM = Tempit > Zinroc = Fuji IX-GP > Ketac-fil = enamel > dentin (where > indicates a statistical difference at p < or = 0.05). Although not as radiopaque as some other intermediate materials tested, the radiopacity of Fuji IX-GP appears sufficient to aid diagnosis.

Calcium Sulfate↗

PubMedDate not supplied

Salivary contamination and bond strength of glass-ionomers to dentin.

This study evaluated the effect of salivary contamination on the shear bond strength of two highly viscous glass ionomer cements (Fuji IX GP Fast and Ketac-Molar Maxicap) to conditioned dentin and assessed the effect of cleaning the contaminated field prior to bonding. The buccal surfaces of 90 human molars and premolars were ground to expose dentin and the teeth were then set in resin. The specimens were divided into two groups for each material, then further subdivided into three groups of 15 teeth each: Group 1--uncontaminated (control), Group 2--dentin contaminated with saliva, Group 3--dentin contaminated, washed and air dried. The specimens were made by bonding the test material to dentin using a 4 mm diameter gelatin capsule. All specimens were protected with varnish and placed in distilled water at 37 degrees C for seven days prior to measuring bond strength in shear. Fractured surfaces were examined visually and by using SEM to assess mode of failure. There were no significant differences in mean shear bond strength among the three test groups for either material (ANOVA). However, shear bond strength of Fuji IX to dentin was significantly greater than Ketac-Molar (p=0.019) for all groups. Weibull analysis showed that contaminated (Group 2) specimens had a greater probability of failure at low stresses. Modes of failure were mostly cohesive for Fuji IX and adhesive/cohesive for Ketac-Molar. In conclusion, salivary contamination did not affect the mean shear bond strength of Fuji IX GP Fast and Ketac-Molar Maxicap to conditioned dentin; however, it increased the probability of failure at low stresses.

Adhesiveness↗

PubMed2001

Shear bond strength of resin composite veneering material to gold alloy with varying metal surface preparations.

STATEMENT OF PROBLEM: Although adequate surface preparation is indispensable to achieve a consistent and durable bond between resin composite materials and the metal substructures of veneered restorations, information on the bonding performance of current metal adhesive systems is limited. PURPOSE: The purpose of this study was to evaluate the surface preparation effects of 4 metal conditioners and 1 adhesive system on bonding between a prosthetic resin composite veneering material and a gold casting alloy. MATERIAL AND METHODS: Four primers containing sulfur derivative monomer and designed for conditioning noble metal alloys (Alloy Primer, Infis Opaque Primer, Metal Primer II, and Metaltite) and a surface modification technique (Siloc) were assessed. Cast disk specimens made of gold alloy (Pontor LFC) were either primed with 1 of the 4 primers or treated with the Siloc system and bonded with a light-activated prosthetic resin composite material (New Metacolor Infis). Control specimens were also prepared without the use of a bonding agent. Shear bond strengths were determined before and after thermocycling (20,000 cycles) for evaluation of bond durability. RESULTS: All of the primed and Siloc-treated groups showed improved 24-hour shear bond strengths compared with the control group. After thermocycling, the groups either primed with the Metaltite conditioner or treated with the Siloc system exhibited the highest mean shear bond strengths. CONCLUSION: The Metaltite conditioner and Siloc system each represent a useful method for improving the bond between the gold alloy and resin composite material tested.

Adhesives↗

PubMed2005

Colour stability of tooth-coloured restorative materials.

The colour stability of the surface and in-depth (2 mm) layer of two resin composites, a laboratory second-generation resin composite and a compomer were evaluated after 24 and 360 hours of water aging under dark and UV light conditions. The influence of various polymerization techniques on color changes was also evaluated. Color differences (deltaE*) showed higher color changes under UV light exposure than under dark storage, both at 24- and 360-hour evaluations. Color changes were statistically higher at the 360-hour assessment, in both conditions of maintenance. Compomer was the least color stable of the materials tested. Additional polymerization significantly decreased the colour change of both composite resins.

Acrylic Resins↗

PubMedDate not supplied

The effect of custom tray material type and adhesive drying time on the tensile bond strength of an impression material/adhesive system.

The purpose of this investigation was to compare the tensile bond strength of one poly(vinyl siloxane) impression material/adhesive system to three different custom tray materials 10 minutes, 48 hours, and 7 days after adhesive application. One autopolymerizing (Fastray) and two light-polymerizing (Triad and Extoral) custom tray resins were examined. The Triad tray resin exhibited the significantly highest mean adhesive tensile bond strengths, and the Fastray resin exhibited the lowest. It was also observed that the 48-hour adhesive drying time group exhibited the highest mean adhesive tensile bond strengths for all the materials tested, and the 10-minute group exhibited the lowest.

Acrylic Resins↗

PubMed1997

Bond strengths of composite resin and compomers in primary and permanent teeth.

Previous clinical and in vitro studies have shown a higher failure rate of composite resins and conventional glass ionomer cements in primary teeth when compared to permanent teeth. A new generation of light-cured glass ionomer cements (compomers) were suggested to be used as restorative materials for the primary teeth. This study was conducted into two parts. The objective of the first part was to compare shear bond strength of compomers (Compoglass and Dyract) and composite resin (Herculite/Optibond) in both primary and permanent teeth. Buccal and lingual surfaces of extracted sound human primary and permanent molars were ground flat on 600-grit SiC paper and divided into 6 groups of 10 surfaces each. The materials were handled according to the instructions of the manufacturer and placed on to the tooth surfaces via clear plastic tubes of 3 mm in diameter. After light curing for 40 seconds, all samples were thermocycled in water bath of 5 degrees F and 55 degrees F for 500 cycles. The samples were embedded in acrylic resin and sheared with an Instron running at a crosshead speed of 0.5 mm/min. Results (mean shear bond strength) were recorded in MPa. Factorial ANOVA revealed that shear bond strength of Herculite/Optibond in the primary teeth (6.07 +/- 2.63) was significantly lower than that of the permanent teeth (17.61 +/- 4.34) (p < 0.0001), but there was no statistically significant difference of bond strength of Compoglass and Dyract between the primary and the permanent teeth. The results from the first part revealed that no materials tested in the primary teeth could provide a shear bond strength of at least 17.6 MPa as recommended. Thus, the objective of the second part of this study was to evaluate shear bond strength of composite resin (Herculite) using three different dentinal bonding agents (Optibond, One-Step and Amalgambond) in the primary teeth. Methods employed in this part were similar to that of the first part. Results showed that Amalgambond provided significantly higher mean shear bond strength (17.96 +/- 5.77) than One-step (11.79 +/- 4.73) and Optibond (6.07 +/-/- 2.63) as tested by Kruskal-Wallis ANOVA and Mann-Whitney U test (p < 0.0001).

Adhesiveness↗

PubMed1989

Biocompatibility testing of a posterior composite and dental cements using a new organ culture model.

Mandibular first molars from day 14 and 17 mouse embryos were cultured in vitro for 7 days in chemically defined Pratt's medium in a submerged culture system. Ameloblast and odontoblast polarization and morphogenesis occurred in the control tooth germs. Discs of Occlusin, Silicate, ChemFil, IRM and Dycal were exposed to the culture system as either fresh material, leached discs (by pre-incubation in media) or the leachate from the incubated discs. Their effects on dental differentiation were assessed histologically. Day 17 tooth germs were slightly more sensitive to the effects of the exogenous agents than day 14 tooth germs. In general, silicate and ChemFil were toxic, IRM was slightly less toxic and the major effect was from the leachate. Dycal was toxic but most of this effect resulted from pH changes in the leachate. Occlusin was the most biocompatible material tested. Only a very mild adverse effect was detected, and this appeared to be caused by an agent (not a pH change) released into the leachate.

Aluminum Silicates↗

PubMed1991

Study of polymeric systems based on 2,2 bis-4(2-hydroxy-3-methacryloyl-oxypropoxy) phenyl propane.

2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane is the basic monomer for a large number of proprietary dental composite filling materials. In this paper, studies have been made of its copolymers with various comonomers. 2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane--tetrahydrofurfuryl methacrylate copolymers, at about the 95/5% v/v level, showed an enhanced modulus over that of the test material itself, to give a Young's modulus of -4.8 GPa. This reflected an enhanced activation energy of the glass transition temperature, indicating a very specific free volume effect of the diluent monomer. Further studies 2,2 bis-4(2-hydroxy-3-methacryloyloxypropoxy) phenyl propane-tetrahydrofurfuryl methacrylate room temperature polymerized copolymers showed that enhanced modulus could be achieved by including in the system small amounts of inhibitor; 0.3% v/v 2,6 di-tertiary butyl phenol elevated the Young's modulus of a benzoyl peroxide--NN-dihydroxy ethyl p-toluidine cured system from 3.1 to 3.6 GPa. Such resins may be useful in improved dental fissure sealants and composite filling materials.

Benzoyl Peroxide↗

PubMed2004

Surface roughness of nanofill and nanohybrid composite resin and ormocer-based tooth-colored restorative materials after several finishing and polishing procedures.

The purpose of this study was to evaluate the effect of several finishing and polishing procedures on the surface roughness of nanofill and nanohybrid composites and ormocer-based dental restorative materials. The materials included a nanofill composite (Supreme); a nanohybrid composite (Grandio); and an ormocer (organically modified ceramic) (Admira). Forty specimens of each material were prepared using a Mylar strip (polyester strip) and randomly divided into four finishing and polishing groups (n =10): (I) Diamond bur/Super-snap Rainbow Technique Kit(Al(2)O(2)-coated, graded abrasive discs); (II) Diamond bur/Astropol and Astrobrush system (silicone abrasive polishers and brush system); (III) Tungsten carbide bur/Super-snap Rainbow Technique Kit; and (IV) Tungsten carbide bur/Astropol and Astro-brush system. The average surface roughness (Ra) in micrometers was measured using a "Mahr Perthometer S4P" Surface Roughness Tester and the data were compared using ANOVA at P <or=0.05. The results of this study indicated that the Mylar strip produced the smoothest surface on all materials and among the finishing-polishing methods the first and the third methods performed significantly smoother surfaces than the second and the fourth methods for the three restoratives. Ormocer (Admira) performed the lowest variability in initial surface roughness among the tested materials. This study has shown that Super-snap abrasive discs produced a smoother surface than the Astropol and Astrobrush silicone polishers for composite and ormocer-based restorative materials, but the results would be valid clinically for readily accessible and flat surfaces i.e., not for all areas in the mouth. Therefore silicone polishers are necessary for posterior areas and for concave and convex surfaces.

Ceramics↗

PubMed2001

An in vitro investigation into the use of resin-modified glass poly(alkenoate) cements as orthodontic bonding agents.

This in vitro study was designed to determine the effect of time on the measured mean force to debond when brackets were bonded using resin-modified glass poly(alkenoate) cements and to compare them with a light-cured diacrylate. Changes in surface topography and composition of the cements were also investigated. Stainless steel orthodontic brackets were bonded to 160 upper premolar teeth in four test groups: Transbond, Fuji Ortho LC, and 3 M Multi-Cure with and without enamel etching. Shear bond testing to failure was performed after 1 hour, 1 week, 1 month, and 1 year. The first three groups were then rebonded and stored for the same time periods before being shear tested again. Debond force was recorded in Newtons and the locus of bond failure was scored using the Adhesive Remnant Index (ARI). Surface topography and composition of the test materials were also studied at time periods of 1 day, and 1, 6, and 18 months, using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The mean force to debond (N) was observed to increase with time in all four test groups, with there being little significant difference between the groups. When the same brackets were rebonded, the mean force to debond reduced. Surface topography and compositional changes over time were only observed with the resin-modified glass poly(alkenoate) cements. Resin-modified glass poly(alkenoate) cements have a mean force to debond comparable with diacrylate bonding agents. However, unlike diacrylates they undergo surface changes with time, the significance of which is unknown.

Acrylic Resins↗

PubMed1992

Comparison of bond strength of six soft denture liners to denture base resin.

The bond strength of six commercial soft denture liners was evaluated using a modified tensile test. The soft denture liners investigated were Prolastic, VinaSoft, Flexor, Molloplast-B, Novus, and Super-Soft. The samples were processed according to the manufacturers' instructions to cured denture base resin (polymethyl methacrylate; PMMA). The soft denture liners were 10 x 10 x 3 mm and were processed between two PMMA blocks. The samples were placed in tension until failure. The mode of failure, cohesive or adhesive, was also recorded. The results of this study showed that the bond strength is related to the components of the materials. Prolastic, VinaSoft, and Flexor had the lowest bond strength to cured PMMA and ranged from 9.6 to 11.3 kg/cm2. Super-Soft, Novus, and Molloplast-B demonstrated better bond strengths and ranged from 16.7 to 17.6 kg/cm2. The bond strength of Novus could be improved by using the recommended bonding agent and bonded Novus at 26.1 kg/cm2 had the highest bond strength of all materials tested.

Adhesiveness↗

PubMedDate not supplied

Comparative study of antioxidant enzymes in tissues surrounding implant in rabbits.

There is a possible role of reactive oxygen species (SROS) in the complication of implants although there is presently little information. The aim of this study was to investigate the alterations in lipid peroxidation (LP) and antioxidant enzyme activities in tissues surrounding implants in rabbits. Thirty New Zealand albino male rabbits were used. They were randomly divided into five groups. The first group (I) was used as control. Groups II, III, IV and V were implanted with stainless steel, ceramic, titanium and polyethylene, respectively. One month after the administration of implant, the tissues surrounding the implant were carefully removed for antioxidant enzyme analysis. Glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase (GR), superoxide dismutases (SOD), glutathione peroxidase (GPx), catalase (CAT) in tissues surrounding the implants in the groups II, III and IV were significantly (p<0.05-p<0.001) lower than in the control group although glutathione S-transferase (GST) activities and LP values were increased. CAT activity and LP level did not decrease in group V. In conclusion, these data demonstrate that there is an increase in lipid peroxidation in the tissues surrounding ceramic and titanium implants of animals whereas there is a decrease in antioxidant enzymes. Oxidative stress plays a very important role in the complications of ceramic and titanium implants. The polyethylene implant seems to be the best of the four implant materials tested.

Animals↗

PubMed1999

Influence of light irradiation on the volumetric change of polyacid-modified resin composites.

OBJECTIVES: Recently, a new restorative material called a 'compomer', which is classified as a polyacid-modified resin composite, has become available. The volumetric shrinkage of compomers may create marginal gaps that influence the bonding ability and longevity of a restoration. Since compomers have been introduced recently, their volumetric change during curing is not fully understood. The purpose of this study was to evaluate the volumetric change of compomers. METHODS: Three compomers, Compoglass (Vivadent), Dyract (Dentsply), and Ionosit Fil (DMG) were employed. The material was placed into a Teflon mould, 4 mm in diameter and 2 mm height, and extruded into the dilatometer. Then the specimens were light activated and the change in the height of the meniscus of water was recorded using a CCD camera and VRC. RESULTS: The average volumetric shrinkages of the compomers after 160 s were 2.4% for Compoglass, 2.7% for Dyract, and 2.1% for Ionosit-Fil. For all materials tested, there was a tendency of increasing volumetric shrinkage with increased irradiation time. CONCLUSIONS: The results of this study indicate that the volumetric change of compomer is influenced by the duration of light exposure, light intensity, and environmental conditions to which the materials are exposed.

Chemical Phenomena↗

PubMed1998

[Effect of various cylinder diameters of implants for lumbar inter-corporeal spinal fusion on compressive strength on the FSU model].

Anterior lumbar interbody fusion (ALIF) has evolved as a minimally invasive technique for treating lumbar instability caused by degenerative lumbar disc disease. A practical surgical method is the lateral retroperitoneal approach in which cylindrical implants are inserted in the intervertebral space. The optimal diameter of these implants remains unclear. The purpose of this biomechanical study was to investigate the influence of implant diameter on selected mechanical properties of the functional spinal units (FSU). In fresh frozen bovine FSU the bone density was first determined and cylindrical implants were then inserted. The FSU were then tested under compression loading in a material-testing machine. A tendency of the "failure loads" to decrease with increasing cylinder diameter was observed. The study reveals a strong correlation between bone density and loading capacity, with higher loads being sustained by the more strongly mineralized bone. In contrast to homogeneous material, in an FSU, larger cylinder diameter does not result in an increase in compression strength.

Animals↗

PubMed1994

Analysis of the general features of the soft tissue response to some metals and ceramics using quantitative histomorphometry.

This article analyzes the general features of the tissue response to orthopedic biomaterials when implanted in the paraspinal muscles in rats for periods between 1 week and 1 year. Using a computer-assisted cell counting method, it was shown that the membrane thickness was a stable parameter that poorly correlated with the other histomorphometric parameters except fibrocyte distance parameters. Macrophages were significant in number only in the short term and were always located at the implant-tissue interface. At 4 weeks, the period corresponding to which macrophages disappeared, fibrocytes were found nearer the interface than at earlier periods and did not migrate for up to 52 weeks, although their densities decreased to 50% of their initial values. Therefore, it can be histomorphometrically confirmed that 1) the presence of an implant induced a delay in the healing process; 2) the immune system was not usually involved in the response to bulk metals; and 3) at early time periods, the presence of PMN cells was correlated to the long-term number of macrophages. On the contrary, the histomorphometric findings suggested that around the tested materials, a large number of macrophages did not induce an immediate or a delayed fibrocyte proliferation. If one considers that a low fibrocyte surface density is related to activated cells surrounded by a matrix high in collagen content, then the large number of macrophages induced the stimulation of collagen synthesis by the fibrocytes already included in the membrane. Accordingly, in the short-term, a high fibrocyte density and few macrophages may be a criterion for testing biocompatibility.

Animals↗

PubMed2004

Neural correlates of retrieval orientation: effects of study-test similarity.

ERPs elicited by correctly classified unstudied items in tests of yes/no recognition memory were used to investigate the neural correlates of retrieval cue processing. Items in Experiment 1 consisted of pictures and their corresponding names, allowing study and test material to be factorially crossed in four separate study-test cycles. The ERPs elicited by unstudied pictures and words were, in each case, more negative-going when the study material belonged to the alternative rather than the same class of items. These findings demonstrate that previously reported ERP "retrieval orientation effects" depend on differences in similarity between study and test items, and not on the form of the sought for material. In Experiments 2a and 2b, study materials were auditory words and pictures, and the test items were visual words. In both experiments, ERPs elicited by unstudied test words were more negative-going when pictures rather than auditory words were the study material. Thus, ERP retrieval orientation effects do not depend on the employment of a copy cue condition. It is proposed that the effects reflect differences in the processing necessary to maximize overlap between cue and memory representations.

Acoustic Stimulation↗