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Sample records for adhesive restorative materials

  1. Quantification of Staphylococcus aureus adhesion forces on various dental restorative materials using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Merghni, Abderrahmen; Kammoun, Dorra; Hentati, Hajer; Janel, Sébastien; Popoff, Michka; Lafont, Frank; Aouni, Mahjoub; Mastouri, Maha

    2016-08-01

    In the oral cavity dental restorative biomaterials can act as a reservoir for infection with opportunistic Staphylococcus aureus pathogen, which can lead to the occurrence of secondary caries and treatment failures. Our aim was to evaluate the adhesion forces by S. aureus on four dental restorative biomaterials and to correlate this finding to differences in specific surface characteristics. Additionally, the influence of salivary conditioning films in exerted adhesion forces was investigated. The substrate hydrophobicity was measured by goniometer and the surface free energy was calculated using the equilibrium advancing contact angle values of water, formamide, and diiodomethane on the tested surfaces. The surface roughness was determined using atomic force microscope (AFM). Additionally, cell force spectroscopy was achieved to quantify the forces that drive cell-substrate interactions. S. aureus bacterium exerted a considerable adhesion forces on various dental restorative materials, which decreased in the presence of saliva conditioning film. The influence of the surface roughness and free energy in initial adhesion appears to be more important than the effect of hydrophobicity, either in presence or absence of saliva coating. Hence, control of surface properties of dental restorative biomaterials is of crucial importance in preventing the attachment and subsequent the biofilm formation.

  2. Ceramic adhesive restorations and biomimetic dentistry: tissue preservation and adhesion.

    PubMed

    Tirlet, Gil; Crescenzo, Hélène; Crescenzo, Dider; Bazos, Panaghiotis

    2014-01-01

    Thanks to sophisticated adhesive techniques in contemporary dentistry, and the development of composite and ceramic materials, it is possible to reproduce a biomimetic match between substitution materials and natural teeth substrates. Biomimetics or bio-emulation allows for the association of two fundamental parameters at the heart of current therapeutic treatments: tissue preservation and adhesion. This contemporary concept makes the retention of the integrity of the maximum amount of dental tissue possible, while offering exceptional clinical longevity, and maximum esthetic results. It permits the conservation of the biological, esthetic, biomechanical and functional properties of enamel and dentin. Today, it is clearly possible to develop preparations allowing for the conservation of the enamel and dentin in order to bond partial restorations in the anterior and posterior sectors therefore limiting, as Professor Urs Belser from Geneva indicates, "the replacement of previous deficient crowns and devitalized teeth whose conservation are justified but whose residual structural state are insufficient for reliable bonding."1 This article not only addresses ceramic adhesive restoration in the anterior area, the ambassadors of biomimetic dentistry, but also highlights the possibility of occasionally integrating one or two restorations at the heart of the smile as a complement to extensive rehabilitations that require more invasive treatment. PMID:25126616

  3. An in vitro microleakage study of class V cavities restored with a new self-adhesive flowable composite resin versus different flowable materials

    PubMed Central

    Sadeghi, Mostafa

    2012-01-01

    Background: Regarding the importance of sealing ability of restorative dental materials, this study was done to assess the microleakage of class V cavities restored with a new self-adhesive flowable composite resin and compare to different flowable materials. Materials and Methods: Seventy standardized class V cavities were prepared on the buccal surface of maxillary premolars teeth. The occlusal and the gingival margins of the cavities were located on the enamel and cementum/dentin, respectively. Teeth were randomly assigned into five groups (n = 14) and restored with different flowable materials following the manufacturer's instructions: groups I and II: EMBRACE WetBond flowable composite resin with and without acid etching and bonding agent, respectively; group III: flowable compomer (Dyract Flow); and IV and V: microhybrid (Tetric Flow) and nanofilled (Premise Flowable) flowable composite resins, respectively. After finishing and polishing, the teeth were stored in distilled water at 37°C, thermocycled, coated with nail varnish, and immersed in a basic fuchsin, and then longitudinally sectioned. Dye penetration was examined with a stereomicroscope and scored separately for occlusal and gingival on a 0-3 ordinal scale. Data were analyzed with Kruskal-Wallis, Mann-Whitney and Wilcoxon tests (α=0.05). Results: EMBRACE WetBond with acid etching and bonding agent had significantly less microleakage at the occlusal margins than those without, but not at cervical margins. Also cavities restored with EMBRACE WetBond without acid etching and bonding agent showed significantly greater microleakage scores than other groups at occlusal margin, but there was no significant difference at the cervical margin. Conclusion: The application of acid etching and bonding agent with EMBRACE WetBond provided better occlusal marginal sealing than those without at class V cavities. PMID:23162589

  4. Adhesion of Dental Materials to Tooth Structure

    NASA Astrophysics Data System (ADS)

    Mitra, Sumita B.

    2000-03-01

    The understanding and proper application of the principles of adhesion has brought forth a new paradigm in the realm of esthetic dentistry. Modern restorative tooth procedures can now conserve the remaining tooth-structure and also provide for the strengthening of the tooth. Adhesive restorative techniques call for the application and curing of the dental adhesive at the interface between the tooth tissue and the filling material. Hence the success of the restoration depends largely on the integrity of this interface. The mechanism of adhesion of the bonding materials to the dental hard tissue will be discussed in this paper. There are four main steps that occur during the application of the dental adhesive to the oral hard tissues: 1) The first step is the creation of a microstructure in the tooth enamel or dentin by means of an acidic material. This can be through the application of a separate etchant or can be accomplished in situ by the adhesive/primer. This agent has to be effective in removing or modifying the proteinaceous “smear” layer, which would otherwise act as a weak boundary layer on the surface to be bonded. 2) The primer/adhesive must then be able to wet and penetrate the microstructure created in the tooth. Since the surface energies of etched enamel and that of etched dentin are different finding one material to prime both types of dental tissues can be quite challenging. 3) The ionomer types of materials, particularly those that are carboxylate ion-containing, can chemically bond with the calcium ions of the hydroxyapatite mineral. 4) Polymerization in situ allows for micromechanical interlocking of the adhesive. The importance of having the right mechanical properties of the cured adhesive layer and its role in absorbing and dissipating stresses encountered by a restored tooth will also be discussed.

  5. Self-Healing Efficiency of Cementitious Materials Containing Microcapsules Filled with Healing Adhesive: Mechanical Restoration and Healing Process Monitored by Water Absorption

    PubMed Central

    Li, Wenting; Jiang, Zhengwu; Yang, Zhenghong; Zhao, Nan; Yuan, Weizhong

    2013-01-01

    Autonomous crack healing of cementitious composite, a construction material that is susceptible to cracking, is of great significance to improve the serviceability and to prolong the longevity of concrete structures. In this study, the St-DVB microcapsules enclosing epoxy resins as the adhesive agent were embedded in cement paste to achieve self-healing capability. The self-healing efficiency was firstly assessed by mechanical restoration of the damaging specimens after being matured. The flexural and compressive configurations were both used to stimulate the localized and distributed cracks respectively. The effects of some factors, including the content of microcapsules, the curing conditions and the degree of damage on the healing efficiency were investigated. Water absorption was innovatively proposed to monitor and characterize the evolution of crack networks during the healing process. The healing cracks were observed by SEM-EDS following. The results demonstrated that the capsule-containing cement paste can achieve the various mechanical restorations depending on the curing condition and the degree of damage. But the voids generated by the surfactants compromised the strength. Though no noticeable improved stiffness obtained, the increasing fracture energy was seen particularly for the specimen acquiring 60% pre-damage. The sorptivity and amount of water decreased with cracks healing by the adhesive, which contributed to cut off and block ingress of water. The micrographs by SEM-EDS also validated that the cracks were bridged by the hardened epoxy as the dominated elements of C and O accounted for 95% by mass in the nearby cracks. PMID:24312328

  6. Self-healing efficiency of cementitious materials containing microcapsules filled with healing adhesive: mechanical restoration and healing process monitored by water absorption.

    PubMed

    Li, Wenting; Jiang, Zhengwu; Yang, Zhenghong; Zhao, Nan; Yuan, Weizhong

    2013-01-01

    Autonomous crack healing of cementitious composite, a construction material that is susceptible to cracking, is of great significance to improve the serviceability and to prolong the longevity of concrete structures. In this study, the St-DVB microcapsules enclosing epoxy resins as the adhesive agent were embedded in cement paste to achieve self-healing capability. The self-healing efficiency was firstly assessed by mechanical restoration of the damaging specimens after being matured. The flexural and compressive configurations were both used to stimulate the localized and distributed cracks respectively. The effects of some factors, including the content of microcapsules, the curing conditions and the degree of damage on the healing efficiency were investigated. Water absorption was innovatively proposed to monitor and characterize the evolution of crack networks during the healing process. The healing cracks were observed by SEM-EDS following. The results demonstrated that the capsule-containing cement paste can achieve the various mechanical restorations depending on the curing condition and the degree of damage. But the voids generated by the surfactants compromised the strength. Though no noticeable improved stiffness obtained, the increasing fracture energy was seen particularly for the specimen acquiring 60% pre-damage. The sorptivity and amount of water decreased with cracks healing by the adhesive, which contributed to cut off and block ingress of water. The micrographs by SEM-EDS also validated that the cracks were bridged by the hardened epoxy as the dominated elements of C and O accounted for 95% by mass in the nearby cracks. PMID:24312328

  7. Fatigue of restorative materials.

    PubMed

    Baran, G; Boberick, K; McCool, J

    2001-01-01

    Failure due to fatigue manifests itself in dental prostheses and restorations as wear, fractured margins, delaminated coatings, and bulk fracture. Mechanisms responsible for fatigue-induced failure depend on material ductility: Brittle materials are susceptible to catastrophic failure, while ductile materials utilize their plasticity to reduce stress concentrations at the crack tip. Because of the expense associated with the replacement of failed restorations, there is a strong desire on the part of basic scientists and clinicians to evaluate the resistance of materials to fatigue in laboratory tests. Test variables include fatigue-loading mode and test environment, such as soaking in water. The outcome variable is typically fracture strength, and these data typically fit the Weibull distribution. Analysis of fatigue data permits predictive inferences to be made concerning the survival of structures fabricated from restorative materials under specified loading conditions. Although many dental-restorative materials are routinely evaluated, only limited use has been made of fatigue data collected in vitro: Wear of materials and the survival of porcelain restorations has been modeled by both fracture mechanics and probabilistic approaches. A need still exists for a clinical failure database and for the development of valid test methods for the evaluation of composite materials. PMID:11603506

  8. Various Effects of Sandblasting of Dental Restorative Materials

    PubMed Central

    Nishigawa, Goro; Maruo, Yukinori; Irie, Masao; Maeda, Naoto; Yoshihara, Kumiko; Nagaoka, Noriyuki; Matsumoto, Takuya; Minagi, Shogo

    2016-01-01

    Background Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials. Methods We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC) group and non-ultrasonic cleaning (NUSC) group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength. Results For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group. Conclusions Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials. PMID:26764913

  9. RADIOPACITY OF RESTORATIVE MATERIALS USING DIGITAL IMAGES

    PubMed Central

    Salzedas, Leda Maria Pescinini; Louzada, Mário Jefferson Quirino; de Oliveira, Antonio Braz

    2006-01-01

    The radiopacity of esthetic restorative materials has been established as an important requirement, improving the radiographic diagnosis. The aim of this study was to evaluate the radiopacity of six restorative materials using a direct digital image system, comparing them to the dental tissues (enamel-dentin), expressed as equivalent thickness of aluminum (millimeters of aluminum). Five specimens of each material were made. Three 2-mm thick longitudinal sections were cut from an intact extracted permanent molar tooth (including enamel and dentin). An aluminum step wedge with 9 steps was used. The samples of different materials were placed on a phosphor plate together with a tooth section, aluminum step wedge and metal code letter, and were exposed using a dental x-ray unit. Five measurements of radiographic density were obtained from each image of each item assessed (restorative material, enamel, dentin, each step of the aluminum step wedge) and the mean of these values was calculated. Radiopacity values were subsequently calculated as equivalents of aluminum thickness. Analysis of variance (ANOVA) indicated significant differences in radiopacity values among the materials (P<0.0001). The radiopacity values of the restorative materials evaluated were, in decreasing order: TPH, F2000, Synergy, Prisma Flow, Degufill, Luxat. Only Luxat had significantly lower radiopacity values than dentin. One material (Degufill) had similar radiopacity values to enamel and four (TPH, F2000, Synergy and Prisma Flow) had significantly higher radiopacity values than enamel. In conclusion, to assess the adequacy of posterior composite restorations it is important that the restorative material to be used has enough radiopacity, in order to be easily distinguished from the tooth structure in the radiographic image. Knowledge on the radiopacity of different materials helps professionals to select the most suitable material, along with other properties such as biocompatibility, adhesion and

  10. Non-thermal atmospheric plasmas in dental restoration: improved resin adhesive penetration

    PubMed Central

    Zhang, Ying; Yu, Qingsong; Wang, Yong

    2014-01-01

    optimize adhesion between tooth substrate and restorative materials. PMID:24859333

  11. Adhesive/Dentin Interface: The Weak Link in the Composite Restoration

    PubMed Central

    Spencer, Paulette; Ye, Qiang; Park, Jonggu; Topp, Elizabeth M.; Misra, Anil; Marangos, Orestes; Wang, Yong; Bohaty, Brenda S.; Singh, Viraj; Sene, Fabio; Eslick, John; Camarda, Kyle; Katz, J. Lawrence

    2010-01-01

    Results from clinical studies suggest that more than half of the 166 million dental restorations that were placed in the United States in 2005 were replacements for failed restorations. This emphasis on replacement therapy is expected to grow as dentists use composite as opposed to dental amalgam to restore moderate to large posterior lesions. Composite restorations have higher failure rates, more recurrent caries, and increased frequency of replacement as compared to amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and premature failure. Under in vivo conditions the bond formed at the adhesive/dentin interface can be the first defense against these noxious, damaging substances. The intent of this article is to review structural aspects of the clinical substrate that impact bond formation at the adhesive/dentin interface; to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface. PMID:20195761

  12. Influence of Nd:YAG laser irradiation on an adhesive restorative procedure.

    PubMed

    Franke, Margarete; Taylor, Arthur Westphal; Lago, Alexandre; Fredel, Márcio Celso

    2006-01-01

    Hard tissue modification by means of laser irradiation is becoming popular in dentistry, since it promotes assorted responses between the tooth and the restorative material. Some studies on the bond strength of adhesive systems to Nd:YAG irradiated teeth have shown distinctive behaviors when irradiation was applied before or after the adhesive agent. This study evaluated the microtensile bond strength of a commercial adhesive system to dentin irradiated with Nd:YAG laser after adhesive application but prior to polymerization. The experiment was conducted in vitro, using freshly extracted human teeth as samples. For the microtensile test, the teeth were separated into 4 different groups according to the energy density of laser irradiation: 0, 5, 10 and 50 J/cm2. The data was analyzed with analysis of variance (ANOVA) and LSD tests, and the results indicated that the group that was irradiated with 5 J/cm2 had significantly higher bond strength values. Adhesive penetration on the etched dentin was observed by scanning electron microscopy, where the images showed better adhesive penetration on dentinal tubules after dentin irradiation with 5 J/cm2. Based on the results of this study, it is possible to conclude that irradiation of dentin with the Nd:YAG laser at low energy densities after application of the adhesive but prior to polymerization might be positive for the adhesive restorative process. PMID:17024950

  13. Fracture resistance of posterior teeth restored with modern restorative materials

    PubMed Central

    Hamouda, Ibrahim M.; Shehata, Salah H.

    2011-01-01

    We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups: Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance. PMID:23554719

  14. Durability of bonds and clinical success of adhesive restorations

    PubMed Central

    Carvalho, Ricardo M.; Manso, Adriana P.; Geraldeli, Saulo; Tay, Franklin R.; Pashley, David H.

    2013-01-01

    Resin-dentin bond strength durability testing has been extensively used to evaluate the effectiveness of adhesive systems and the applicability of new strategies to improve that property. Clinical effectiveness is determined by the survival rates of restorations placed in non-carious cervical lesions (NCCL). While there is evidence that the bond strength data generated in laboratory studies somehow correlates with the clinical outcome of NCCL restorations, it is questionable whether the knowledge of bonding mechanisms obtained from laboratory testing can be used to justify clinical performance of resin-dentin bonds. There are significant morphological and structural differences between the bonding substrate used in in vitro testing versus the substrate encountered in NCCL. These differences qualify NCCL as a hostile substrate for bonding, yielding bond strengths that are usually lower than those obtained in normal dentin. However, clinical survival time of NCCL restorations often surpass the durability of normal dentin tested in the laboratory. Likewise, clinical reports on the long-term survival rates of posterior composite restorations defy the relatively rapid rate of degradation of adhesive interfaces reported in laboratory studies. This article critically analyzes how the effectiveness of adhesive systems is currently measured, to identify gaps in knowledge where new research could be encouraged. The morphological and chemical analysis of bonded interfaces of resin composite restorations in teeth that had been in clinical service for many years, but were extracted for periodontal reasons, could be a useful tool to observe the ultrastructural characteristics of restorations that are regarded as clinically acceptable. This could help determine how much degradation is acceptable for clinical success. PMID:22192252

  15. Nanoleakage of Class V Resin Restorations Using Two Nanofilled Adhesive Systems

    PubMed Central

    Al-Agha, Ebaa I; Alagha, Mustafa I

    2015-01-01

    Background: This study was carried out to evaluate the nanoleakage of two types of nanofilled adhesive systems in Class V composite resin restorations. Materials and Methods: Totally 60 human premolars were randomly assigned to two groups (n = 30). Standardized round Class V cavities (enamel and dentin margins) were prepared. A total-etch (N-Bond total etch) (Ivoclar Vivadent) and self-etching (N-Bond self-etch) (Ivoclar Vivadent) adhesive system were evaluated. The cavities were restored incrementally with nanohybird composite resin (Tetric N-Ceram). The teeth were sectioned into a series of 1 mm thick beams then they were immersed in the prepared ammoniacal silver nitrate tracer solution for 24 h in a black photo-film container to ensure total darkness. The beams were then rinsed with distilled water, and immersed in photo-developing solution for eight hours then they were subjected to the nanoleakage evaluation. The specimens were analyzed in the environmental scanning electron operated with backscattered electron mode at ×1000 magnification. Results: Self-etch adhesive recorded higher nanoleakage % mean value than the total-etch adhesive. The difference in nanoleakage % mean values between total and self-etch adhesive was statistically significant. Conclusion: The self-etch adhesive had statistically significant higher nanoleakage mean values than the total-etch adhesive. PMID:26229363

  16. Application of color image processing and low-coherent optical computer tomography in evaluation of adhesive interfaces of dental restorations

    NASA Astrophysics Data System (ADS)

    Bessudnova, Nadezda O.; Shlyapnikova, Olga A.; Venig, Sergey B.; Genina, Elina A.; Sadovnikov, Alexandr V.

    2015-03-01

    Durability of bonded interfaces between dentin and a polymer material in resin-based composite restorations remains a clinical dentistry challenge. In the present study the evolution of bonded interfaces in biological active environment is estimated in vivo. A novel in vivo method of visual diagnostics that involves digital processing of color images of composite restorations and allows the evaluation of adhesive interface quality over time, has been developed and tested on a group of volunteers. However, the application of the method is limited to the analysis of superficial adhesive interfaces. Low-coherent optical computer tomography (OCT) has been tested as a powerful non-invasive tool for in vivo, in situ clinical diagnostics of adhesive interfaces over time. In the long-term perspective adhesive interface monitoring using standard methods of clinical diagnostics along with colour image analysis and OCT could make it possible to objectivise and prognosticate the clinical longevity of composite resin-based restorations with adhesive interfaces.

  17. Effect of Adhesive Pretreatments on Marginal Sealing of Aged Nano-ionomer Restorations

    PubMed Central

    Shafiei, Fereshteh; Akbarian, Sahar; Karim Etminan, Mohammad

    2015-01-01

    Background and aims. Nano-ionomer (NI) interacts with tooth structures superficially, and there is a concern about the enamel bonding ability of mild self-etch Ketac primer. This study compared the effect of different adhesive procedures (self-etching and etch-and-rinse approach) on long-term marginal microleakage of nano-filled resin-modified glass-ionomer (NI) cervical restorations. Materials and methods. Class V cavities were prepared on 72 maxillary premolars. The teeth were divided into six groups: G1: No treatment (NC); G2: Ketac primer (K primer); G3: Etchant + Ketac primer (E+K primer); G4: Self-etch adhesive (Bond Force); G5: Etchant + Bond Force (E+Bond Force); G6: Etchant + Adper Single Bond (Etch and rinse adhesive). All the cavities were restored with Ketac N100. The samples were stored in water for 6 months and thermocycled for 2000 cycles. Marginal sealing was assessed using dye penetration technique. Data were analyzed with non-parametric tests (α=0.05). Results. All the adhesive pretreatments resulted in a lower marginal leakage than that of NC (P≤0.01), except for E+Bond Force at the dentin margin. There was no significant difference between K primer and Bond Force. Microleakage differed significantly between K primer pretreatment and E+K primer (P=0.003), E+Bond Force (P=0.002) and etch-and-rinse adhesive (P=0.001) at the enamel margin, but it did not differ at the dentin margin. E+ Bond Force group showed insignificantly lower leakage at the enamel margin and significantly higher leakage at the dentin margin (P=0.02). Conclusion. Etch-and-rinse adhesive and selective enamel etching along with self-etch adhesive/Ketac primer might improve marginal sealing of aged nano-ionomer restoration. PMID:26697146

  18. Effect of Adhesive Pretreatments on Marginal Sealing of Aged Nano-ionomer Restorations.

    PubMed

    Shafiei, Fereshteh; Akbarian, Sahar; Karim Etminan, Mohammad

    2015-01-01

    Background and aims. Nano-ionomer (NI) interacts with tooth structures superficially, and there is a concern about the enamel bonding ability of mild self-etch Ketac primer. This study compared the effect of different adhesive procedures (self-etching and etch-and-rinse approach) on long-term marginal microleakage of nano-filled resin-modified glass-ionomer (NI) cervical restorations. Materials and methods. Class V cavities were prepared on 72 maxillary premolars. The teeth were divided into six groups: G1: No treatment (NC); G2: Ketac primer (K primer); G3: Etchant + Ketac primer (E+K primer); G4: Self-etch adhesive (Bond Force); G5: Etchant + Bond Force (E+Bond Force); G6: Etchant + Adper Single Bond (Etch and rinse adhesive). All the cavities were restored with Ketac N100. The samples were stored in water for 6 months and thermocycled for 2000 cycles. Marginal sealing was assessed using dye penetration technique. Data were analyzed with non-parametric tests (α=0.05). Results. All the adhesive pretreatments resulted in a lower marginal leakage than that of NC (P≤0.01), except for E+Bond Force at the dentin margin. There was no significant difference between K primer and Bond Force. Microleakage differed significantly between K primer pretreatment and E+K primer (P=0.003), E+Bond Force (P=0.002) and etch-and-rinse adhesive (P=0.001) at the enamel margin, but it did not differ at the dentin margin. E+ Bond Force group showed insignificantly lower leakage at the enamel margin and significantly higher leakage at the dentin margin (P=0.02). Conclusion. Etch-and-rinse adhesive and selective enamel etching along with self-etch adhesive/Ketac primer might improve marginal sealing of aged nano-ionomer restoration. PMID:26697146

  19. Bacterial Adhesion of Porphyromonas Gingivalis on Provisional Fixed Prosthetic Materials

    PubMed Central

    Zortuk, Mustafa; Kesim, Servet; Kaya, Esma; Özbilge, Hatice; Kiliç, Kerem; Çölgeçen, Özlem

    2010-01-01

    Background: When provisional restorations are worn for long term period, the adhesion of bacteria becomes a primary factor in the development of periodontal diseases. The aims of this study were to evaluate the surface roughness and bacterial adhesion of four different provisional fixed prosthodon-tic materials. Methods: Ten cylindrical specimens were prepared from bis-acrylic composites (PreVISION CB and Protemp 3 Garant), a light-polymerized composite (Revotek LC), and a polymethyl methacrylate-based (Dentalon) provisional fixed prosthodontic materials. Surface roughness was assessed by profilometry. The bacterial adhesion test was applied using Porphyromonas gingivalis (P. gingivalis) and spectro-fluorometric method. Statistical analysis was performed using ANOVA and Dunnett t-tests. Results: All tested materials were significantly rougher than glass (P < 0.05). Revotek LC had the greatest fluorescence intensity, PreVISION and Protemp 3 Garant had moderate values and all of them had significantly more bacterial adhesion compared to glass (P < 0.05). Dentalon had the lowest fluorescence intensity among the provisional fixed prosthodontic materials. Conclusion: The quantity of bacterial adhesion and surface roughness differed among the assessed provisional fixed prosthodontic materials. The light-polymerized provisional material Revotek LC had rougher surface and more bacterial adhesion compared with the others. PMID:21448445

  20. Adhesion and wear resistance of materials

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1986-01-01

    Recent studies into the nature of bonding at the interface between two solids in contact or a solid and deposited film have provided a better understanding of those properties important to the adhesive wear resistance of materials. Analytical and experimental progress are reviewed. For simple metal systems the adhesive bond forces are related to electronic wave function overlap. With metals in contact with nonmetals, molecular-orbital energy, and density of states, respectively can provide insight into adhesion and wear. Experimental results are presented which correlate adhesive forces measured between solids and the electronic surface structures. Orientation, surface reconstruction, surface segregation, adsorption are all shown to influence adhesive interfacial strength. The interrelationship between adhesion and the wear of the various materials as well as the life of coatings applied to substrates are discussed. Metallic systems addressed include simple metals and alloys and these materials in contact with themselves, both oxide and nonoxide ceramics, diamond, polymers, and inorganic coating compounds, h as diamondlike carbon.

  1. Structural adhesives for missile external protection material

    NASA Astrophysics Data System (ADS)

    Banta, F. L.; Garzolini, J. A.

    1981-07-01

    Two basic rubber materials are examined as possible external substrate protection materials (EPM) for missiles. The analysis provided a data base for selection of the optimum adhesives which are compatible with the substrate, loads applied and predicted bondline temperatures. Under the test conditions, EA934/NA was found to be the optimum adhesive to bond VAMAC 2273 and/or NBR/EPDM 9969A to aluminum substrate. The optimum adhesive for composite structures was EA956. Both of these adhesives are two-part epoxy systems with a pot life of approximately two hours. Further research is suggested on field repair criteria, nuclear hardness and survivability effects on bondline, and ageing effects.

  2. Directly Placed Restorative Materials: Review and Network Meta-analysis.

    PubMed

    Schwendicke, F; Göstemeyer, G; Blunck, U; Paris, S; Hsu, L-Y; Tu, Y-K

    2016-06-01

    For restoring cavitated dental lesions, whether carious or not, a large number of material combinations are available. We aimed to systematically review and synthesize data of comparative dental restorative trials. A systematic review was performed. Randomized controlled trials published between 2005 and 2015 were included that compared the survival of ≥2 restorative and/or adhesive materials (i.e., no need for restorative reintervention). Pairwise and Bayesian network meta-analyses were performed, with separate evaluations for cervical cavitated lesions and load-bearing posterior cavitated lesions in permanent and primary teeth. A total of 11,070 restorations (5,330 cervical, 5,740 load bearing) had been placed in 3,633 patients in the included trials. Thirty-six trials investigated restoration of cervical lesions (all in permanent teeth) and 36 of load-bearing lesions (8 in primary and 28 in permanent teeth). Resin-modified glass ionomer cements had the highest chance of survival in cervical cavitated lesions; composites or compomers placed via 2-step self-etch and 3-step etch-and-rinse adhesives were ranked next. Restorations placed with 2-step etch-and-rinse or 1-step self-etch adhesives performed worst. For load-bearing restorations, conventional composites had the highest probability of survival, while siloranes were found least suitable. Ambiguity remains regarding which adhesive strategy to use in load-bearing cavitated lesions. Most studies showed high risk of bias, and several comparisons were prone for publication bias. If prioritized for survival, resin-modified glass ionomer cements might be recommended to restore cervical lesions. For load-bearing ones, conventional or bulk fill composites seem most suitable. The available evidence is quantitatively and qualitatively insufficient for further recommendations, especially with regard to adhesive strategies in posterior load-bearing situations. Moreover, different material classifications might yield

  3. Testing adhesion of direct restoratives to dental hard tissue - a review.

    PubMed

    Salz, Ulrich; Bock, Thorsten

    2010-10-01

    This articles concerns itself with the testing of adhesion between direct restoratives and dental hard tissue, ie, enamel and dentin. The aim is to survey available methods for adhesion testing and influential parameters affecting experimental outcome. The testing of adhesion to indirect restorative materials, eg, ceramics and metals, is beyond the scope of this article and shall be discussed elsewhere. The longevity and success of modern dental restorations very often relies on potent dental adhesives to provide durable bonds between the dental hard substance and the restorative composite. To predict the clinical outcome of such restorative treatment, a large variety of in vitro laboratory tests and clinical in vivo experiments have been devised, analyzed, and published. The purpose of this review is to provide a current overview of bond strength testing methods and their applicability to the characterization of dental adhesives. Regardless of the method employed, subtle variations in sample preparation may already severely impact test results, usually necessitating at least co-testing of a well-known internal reference to allow conclusive interpretation. This article attempts to list and discuss the most influential parameters, such as substrate nature, age, health status, storage, clinically relevant pre-treatment, and sample preparation. Special attention is devoted to the last aspect, as numerous publications have stressed the tremendous influence of preparatory parameters on the validity and scope of obtained data. Added to the large variety of such factors, an equally large diversity of load-applying procedures exists to actually quantify adhesion between composites and dental hard substance. This article summarizes the basics of macro and micro approaches to shear and tensile bond strength testing, as well as push- and pull-out tests. The strengths and weaknesses inherent to each method and influential test parameters are reviewed and methods for

  4. Microleakage of Posterior Composite Restorations with Fiber Inserts Using two Adhesives after ging

    PubMed Central

    Sharafeddin, F; Yousefi, H; Modiri, Sh; Tondari, A; Safaee Jahromi, SR

    2013-01-01

    Statement of Problem: Microleakage is one of the most frequent problems associated with resin composites, especially at the gingival margin of posterior restorations. Insertion of fibers in composite restorations can reduce the total amount of composite and help to decrease the shrinkage. Purpose: The aim of this study was to evaluate the effect of polyethylene fiber inserts on gingival microleakage of class II composite restorations using two different adhesive systems. Materials and Method: In this experimental study, class II cavities were prepared on 60 premolars. The gingival floor was located 1.0 mm below the CEJ. Dimension of each cavity were 3 mm buccolingually and 1.5 mm in axial depth. The specimens were divided into 4 groups according to the adhesive type and fiber insert (n=4). Single bond and Clearfill SE bond and Filtek p60 were used to restore the cavities. In groups without fiber inserts composite was adapted onto cavities using layering technique. For cavities with fiber inserts, 3 mm piece of fiber insert was placed onto the composite increment and cured. The specimens were stored in distilled water at 37oC for 6 months. All specimens were subjected to 3000 thermo-cycling. The tooth surfaces except for 1 mm around the restoration margins covered with two layers of nail varnish .The teeth were immersed in 2% Basic Fuchsin for 24 hours, then rinsed and sectioned mesiodistally. The microleakage was determined under a stereomicroscope (40X). Data were statistically analyzed by Kruskal-wallis and Mann-Whitney U tests (p< 0.05). Results: The Kruskal-Wallis test revealed no significant differences in mean microleakage scores among all groups (p= 0.281). Conclusion: Use of polyethylene fiber inserts and etch-and-rinse and self-etch adhesives had no effect on microleakage in class II resin composite restorations with gingival margins below the CEJ after 6- month water storage. PMID:24724129

  5. Adhesive bonding of carbon and ceramic materials

    SciTech Connect

    Kravetskii, G.A.; Anikin, L.T.; Demin, A.V.; Butyrin, G.M.

    1995-12-01

    On the basis of phenol resins and high-melting powder fillers, adhesives for bonding carbon and ceramic materials have been developed at NIIGRAFIT that allow adhesively bonded parts to be used at temperatures as high as 1500 to 1800{degrees}C, Some properties of those adhesives are covered in. The present paper describes results of recent investigations of the heat- and corrosion-resistance of the NIIGRAFIT`s adhesives. As the subjects of investigations were taken adhesives differing in the powder filler composition. Moreover, one adhesive (SVK) was subjected to a preliminary heat treatment (1200{degrees}C, 1 h, Ar) to fully complete the interaction processes between powder components and a binder coke.

  6. Effect of different adhesive strategies on the post-operative sensitivity of class I composite restorations

    PubMed Central

    Sancakli, Hande Sar; Yildiz, Esra; Bayrak, Isil; Ozel, Sevda

    2014-01-01

    Objective: To evaluate the post-operative sensitivity of occlusal restorations using different dentin adhesives performed by an undergraduate and a post-doctorate dentist. Materials and Methods: One hundred and eighty-eight molar occlusal restorations were placed in 39 patients (ages between 18 and 30) using 3 different kind of adhesive systems; Optibond FL (OBF), Clearfil Protect Bond (CPB), and iBond (IB) by a post-doctorate dentist or a fifth-year dental student according to the manufacturers’ instructions. Post-operative sensitivity to cold and air was evaluated using a Visual Analog Scale (VAS) after 24 hours, 30, 90, and 180 days. Data were analyzed using the Mann-Whitney U and Friedman tests (P < 0.05). Results: Post-operative sensitivity scores for OBF and CPB were higher for the dental student (P < 0.05), while IB scores did not differ statistical significantly according to the operator (P > 0.05). Conclusion: Operator skill and experience appears to play a role in determining the outcome of post-operative sensitivity of multi-step adhesive systems although the post-operative sensitivity was low. It is suggested that the less experienced clinicians (rather than experienced clinicians) should better use the self-etching dentin bonding systems with reduced application steps to minimize the potential risk of post-operative sensitivity of dental adhesives. PMID:24966741

  7. Microleakage of Dual-Cured Adhesive Systems in Class V Composite Resin Restorations

    PubMed Central

    Kasraie, S.; Azarsina, M.; Khamverdi, Z.; Shokraneh, F.

    2012-01-01

    Objective: Microleakage is a major factor affecting longevity of composite restorations. This study evaluated the effect of polymerization mode of bonding agent on microleakage of composite restorations. Materials and Methods: Forty-eight Class V cavities were prepared on buccal and lingual surfaces of 24 extracted human premolars. Occlusal and gingival margins were placed in the enamel and dentin, respectively. Teeth were divided into four groups as follows: Group I: Optibond Solo Plus (light-cured); Group II: Optibond Solo Plus (dual-cured); Group III: Prime & Bond NT (light-cured), Group IV: Prime & Bond NT (dual-cured). Teeth were restored using Z250 composite in three increments. After polishing the restorations, samples were thermocycled for 1000 cycles and stored in distilled water for 3 months. Then they were placed in 2% fuchsine solution for 48 hours. The samples were sectioned longitudinally and evaluated for microleakage under a stereomicroscope at ×40 magnification. Dye penetration was scored on a 0–3 ordinal scale. Data were analyzed using Kruskal-Wallis, Bonferroni and Wilcoxon signed ranks test. Results: Microleakage was significantly lower in enamel margins compared to dentin margins (P<0.05); multiple comparisons by Bonferroni tests revealed that the only factor with significant effect on leakage of the restoration is location of the restoration margin. Mode of adhesive polymerization had no significant influence on microleakage (P>0.05). Prime & Bond NT had less microleakage compared to Optibond SoloPlus, but the difference was not significant (P>0.05). Conclusion: There was no difference in the amount of microleakage in Class V composite restorations using light-cured and dual-cured bonding systems. Dentinal margins of restorations exhibited more microleakage than enamel margins. PMID:23066474

  8. INFLUENCE OF THERMAL STRESS ON MARGINAL INTEGRITY OF RESTORATIVE MATERIALS

    PubMed Central

    Cenci, Maximiliano Sérgio; Pereira-Cenci, Tatiana; Donassollo, Tiago Aurélio; Sommer, Leandro; Strapasson, André; Demarco, Flávio Fernando

    2008-01-01

    The aim of this study was to evaluate the influence of thermal stress on the marginal integrity of restorative materials with different adhesive and thermal properties. Three hundred and sixty Class V cavities were prepared in buccal and lingual surfaces of 180 bovine incisors. Cervical and incisal walls were located in dentin and enamel, respectively. Specimens were restored with resin composite (RC); glass ionomer (GI) or amalgam (AM), and randomly assigned to 18 groups (n=20) according to the material, number of cycles (500 or 1,000 cycles) and dwell time (30 s or 60 s). Dry and wet specimens served as controls Specimens were immersed in 1% basic fuchsine solution (24 h), sectioned, and microleakage was evaluated under x40 magnification. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests: Thermal cycling regimens increased leakage in all AM restorations (p<0.05) and its effect on RC and GI restorations was only significant when a 60-s dwell time was used (p<0.05). Marginal integrity was more affected in AM restorations under thermal cycling stress, whereas RC and GI ionomer restoration margins were only significantly affected only under longer dwell times. PMID:19089200

  9. Fracture and adhesion of soft materials: a review

    NASA Astrophysics Data System (ADS)

    Creton, Costantino; Ciccotti, Matteo

    2016-04-01

    Soft materials are materials with a low shear modulus relative to their bulk modulus and where elastic restoring forces are mainly of entropic origin. A sparse population of strong bonds connects molecules together and prevents macroscopic flow. In this review we discuss the current state of the art on how these soft materials break and detach from solid surfaces. We focus on how stresses and strains are localized near the fracture plane and how elastic energy can flow from the bulk of the material to the crack tip. Adhesion of pressure-sensitive-adhesives, fracture of gels and rubbers are specifically addressed and the key concepts are pointed out. We define the important length scales in the problem and in particular the elasto-adhesive length Γ/E where Γ is the fracture energy and E is the elastic modulus, and how the ratio between sample size and Γ/E controls the fracture mechanisms. Theoretical concepts bridging solid mechanics and polymer physics are rationalized and illustrated by micromechanical experiments and mechanisms of fracture are described in detail. Open questions and emerging concepts are discussed at the end of the review.

  10. Fracture and adhesion of soft materials: a review.

    PubMed

    Creton, Costantino; Ciccotti, Matteo

    2016-04-01

    Soft materials are materials with a low shear modulus relative to their bulk modulus and where elastic restoring forces are mainly of entropic origin. A sparse population of strong bonds connects molecules together and prevents macroscopic flow. In this review we discuss the current state of the art on how these soft materials break and detach from solid surfaces. We focus on how stresses and strains are localized near the fracture plane and how elastic energy can flow from the bulk of the material to the crack tip. Adhesion of pressure-sensitive-adhesives, fracture of gels and rubbers are specifically addressed and the key concepts are pointed out. We define the important length scales in the problem and in particular the elasto-adhesive length Γ/E where Γ is the fracture energy and E is the elastic modulus, and how the ratio between sample size and Γ/E controls the fracture mechanisms. Theoretical concepts bridging solid mechanics and polymer physics are rationalized and illustrated by micromechanical experiments and mechanisms of fracture are described in detail. Open questions and emerging concepts are discussed at the end of the review. PMID:27007412

  11. Adhesion of Pseudomonas fluorescens onto nanophase materials

    NASA Astrophysics Data System (ADS)

    Webster, Thomas J.; Tong, Zonghua; Liu, Jin; Banks, M. Katherine

    2005-07-01

    Nanobiotechnology is a growing area of research, primarily due to the potentially numerous applications of new synthetic nanomaterials in engineering/science. Although various definitions have been given for the word 'nanomaterials' by many different experts, the commonly accepted one refers to nanomaterials as those materials which possess grains, particles, fibres, or other constituent components that have one dimension specifically less than 100 nm. In biological applications, most of the research to date has focused on the interactions between mammalian cells and synthetic nanophase surfaces for the creation of better tissue engineering materials. Although mammalian cells have shown a definite positive response to nanophase materials, information on bacterial interactions with nanophase materials remains elusive. For this reason, this study was designed to assess the adhesion of Pseudomonas fluorescens on nanophase compared to conventional grain size alumina substrates. Results provide the first evidence of increased adhesion of Pseudomonas fluorescens on alumina with nanometre compared to conventional grain sizes. To understand more about the process, polymer (specifically, poly-lactic-co-glycolic acid or PLGA) casts were made of the conventional and nanostructured alumina surfaces. Results showed similar increased Pseudomonas fluorescens capture on PLGA casts of nanostructured compared to conventional alumina as on the alumina itself. For these reasons, a key material property shown to enhance bacterial adhesion was elucidated in this study for both polymers and ceramics: nanostructured surface features.

  12. The role of material properties in adhesion

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1984-01-01

    When two solid surfaces are brought into contact strong adhesive bond forces can develop between the materials. The magnitude of the forces will depend upon the state of the surfaces, cleanliness and the fundamental properties of the two solids, both surface and bulk. Adhesion between solids is addressed from a theoretical consideration of the electronic nature of the surfaces and experimentally relating bond forces to the nature of the interface resulting from solid state contact. Surface properties correlated with adhesion include, atomic or molecular orientation, reconstruction and segregation as well as the chemistry of the surface specie. Where dissimilar solids are in contact the contribution of each is considered as is the role of their interactive chemistry on bond strength. Bulk properties examined include elastic and plastic behavior in the surficial regions, cohesive binding energies, crystal structure, crystallographic orientation and state. Materials examined with respect to interfacial adhesive interactions include metals, alloys, ceramics, polymers and diamond. They are reviewed both in single and polycrystalline form. The surfaces of the contacting solids are studied both in the atomic or molecularly clean state and in the presence of selected surface contaminants.

  13. Abrasion of restorative materials by toothaste.

    PubMed

    Heath, J R; Wilson, H J

    1976-04-01

    The procedure developed in this investigation is suitable for determining the abrasion resistance of restorative materials to toothbrush/dentifrice abrasion. Ideally, a restoration should have an abrasion resistance similar to that of enamel. Of the materials tested, gold was the only one that wore slightly less than enamel, whilst amalgam wore almost twice as quickly. The silicate material and composites (excluding TD.71) wear away 2-4 times faster than enamel. TD.71 and especially the unfilled resin exhibited very high rates of abrasion. After prolonged toothbrush/dentifrice abrasion, the surfaces of gold and amalgam were considerably smoother than those of the silicate and composite materials. PMID:1066445

  14. Adhesion of Particulate Materials to Mesostructured Polypyrrole

    NASA Astrophysics Data System (ADS)

    Hoss, Darby; Knepper, Robert; Hotchkiss, Peter; Tappan, Alexander; Boudouris, Bryan; Beaudoin, Stephen

    Interactions based on van der Waals (vdW) forces will influence the performance and reliability of mesostructured polypyrrole swabs used for the collection and detection of trace particles. The vdW adhesion force between materials is described by the Hamaker constant, and these constants are measured via optical and dielectric properties (i.e., according to Lifshitz theory), inverse gas chromatography (IGC), and contact angle measurements. Here, contact angle measurements were performed on films of several common materials and used to estimate Hamaker constants. This, in turn, will allow for the tuning of the design properties associated with the polypyrrole swabs. A comparison of these results to Hamaker constants estimated using Lifshitz Theory and IGC reveals the fundamental behavior of the materials. The Hamaker constants were then used in a new computational vdW adhesion model. The idealized model describes particle adhesion to an array of mesostrucures. This model elucidates the importance of where the particle makes contact with the mesostructure and the independence of vdW forces generated by each mesostructure. These results will facilitate the rational design of polypyrrole swabs optimized for harvesting microscale particles of trace materials.

  15. Adherence of Streptococcus mutans to Fiber-Reinforced Filling Composite and Conventional Restorative Materials

    PubMed Central

    Lassila, Lippo V.J; Garoushi, Sufyan; Tanner, Johanna; Vallittu, Pekka K; Söderling, Eva

    2009-01-01

    Objectives. The aim was to investigate the adhesion of Streptococcus mutans (S. mutans) to a short glass fibers reinforced semi-IPN polymer matrix composite resin. The effect of surface roughness on adhesion was also studied. For comparison, different commercial restorative materials were also evaluated. Materials and Methods. Experimental composite FC resin was prepared by mixing 22.5 wt% of short E-glass fibers, 22.5 wt% of IPN-resin and 55 wt% of silane treated silica fillers using high speed mixing machine. Three direct composite resins (Z250, Grandio and Nulite), resin-modified glass ionomers (Fuji II LC), amalgam (ANA 2000), fiber-reinforced composite (FRC) (everStick and Ribbond), and pre-fabricated ceramic filling insert (Cerana class 1) were tested in this study. Enamel and dentin were used as controls. The specimens (n=3/group) with or without saliva were incubated in a suspension of S. mutans allowing initial adhesion to occur. For the enumeration of cells on the disc surfaces as colony forming units (CFU) the vials with the microbe samples were thoroughly Vortex-treated and after serial dilutions grown anaerobically for 2 days at +37°C on Mitis salivarius agars (Difco) containing bacitracin. Bacterial adhesion was also evaluated by using scanning electron microscopy. Surface roughness (Ra) of the materials was also determined using a surface profilometer. All results were statistically analyzed with one-way analysis of variance (ANOVA). Results. Composite FC resin and other commercial restorative materials showed similar adhesion of S. mutans, while adhesion to dentin and enamel was significantly higher (p<0.05). Surface roughness had no effect on bacterial adhesion. Saliva coating significantly decreased the adhesion for all materials (p<0.05). Composite FC resin had a significantly higher Ra value than control groups (p<0.05). Conclusions. Short fiber-reinforced composite with semi-IPN polymer matrix revealed similar S. mutans adhesion than

  16. Adherence of Streptococcus mutans to Fiber-Reinforced Filling Composite and Conventional Restorative Materials.

    PubMed

    Lassila, Lippo V J; Garoushi, Sufyan; Tanner, Johanna; Vallittu, Pekka K; Söderling, Eva

    2009-01-01

    OBJECTIVES.: The aim was to investigate the adhesion of Streptococcus mutans (S. mutans) to a short glass fibers reinforced semi-IPN polymer matrix composite resin. The effect of surface roughness on adhesion was also studied. For comparison, different commercial restorative materials were also evaluated. MATERIALS AND METHODS.: Experimental composite FC resin was prepared by mixing 22.5 wt% of short E-glass fibers, 22.5 wt% of IPN-resin and 55 wt% of silane treated silica fillers using high speed mixing machine. Three direct composite resins (Z250, Grandio and Nulite), resin-modified glass ionomers (Fuji II LC), amalgam (ANA 2000), fiber-reinforced composite (FRC) (everStick and Ribbond), and pre-fabricated ceramic filling insert (Cerana class 1) were tested in this study. Enamel and dentin were used as controls. The specimens (n=3/group) with or without saliva were incubated in a suspension of S. mutans allowing initial adhesion to occur. For the enumeration of cells on the disc surfaces as colony forming units (CFU) the vials with the microbe samples were thoroughly Vortex-treated and after serial dilutions grown anaerobically for 2 days at +37 degrees C on Mitis salivarius agars (Difco) containing bacitracin. Bacterial adhesion was also evaluated by using scanning electron microscopy. Surface roughness (Ra) of the materials was also determined using a surface profilometer. All results were statistically analyzed with one-way analysis of variance (ANOVA). RESULTS.: Composite FC resin and other commercial restorative materials showed similar adhesion of S. mutans, while adhesion to dentin and enamel was significantly higher (p<0.05). Surface roughness had no effect on bacterial adhesion. Saliva coating significantly decreased the adhesion for all materials (p<0.05). Composite FC resin had a significantly higher Ra value than control groups (p<0.05). CONCLUSIONS.: Short fiber-reinforced composite with semi-IPN polymer matrix revealed similar S. mutans adhesion

  17. Native Plant Materials for Sagebrush Steppe Restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An increasing number and diversity of plant materials are becoming available for restoration of sagebrush steppe lands. Some species that have previously been available only from wildland harvest are now more economically produced with better seed quality in cultivated fields. Others are now avail...

  18. Recommendations for conducting controlled clinical studies of dental restorative materials.

    PubMed

    Hickel, R; Roulet, J-F; Bayne, S; Heintze, S D; Mjör, I A; Peters, M; Rousson, V; Randall, R; Schmalz, G; Tyas, M; Vanherle, G

    2007-03-01

    designs, guidelines for design, randomization, number of subjects, characteristics of participants, clinical assessment, standards and calibration, categories for assessment, criteria for evaluation, and supplemental documentation. Part 2 of the review considers categories of assessment for esthetic evaluation, functional assessment, biological responses to restorative materials, and statistical analysis of results. The overall review represents a considerable effort to include a range of clinical research interests over the past years. As part of the recognition of the importance of these suggestions, the review is being published simultaneously in identical form in both the "Journal of Adhesive Dentistry" and the "Clinical Oral Investigations." Additionally an extended abstract will be published in the "International Dental Journal" giving a link to the web full version. This should help to introduce these considerations more quickly to the scientific community. PMID:17262225

  19. Influence of adhesive system and bevel preparation on fracture strength of teeth restored with composite resin.

    PubMed

    Coelho-de-Souza, Fábio Herrmann; Rocha, Analice da Cunha; Rubini, Alessandro; Klein-Júnior, Celso Afonso; Demarco, Flávio Fernando

    2010-01-01

    The aim of this study was to evaluate the fracture strength of teeth with different cavosurface margin cavity preparations and restored with composite resin and different adhesive systems. Eighty premolars were randomly divided in 8 groups, as follow: G1- sound teeth; G2- MOD preparation (no restoration); G3- Adper Single Bond without bevel preparation (butt joint); G4- Adper Single Bond with bevel preparation; G5- Adper Single Bond with chamfer preparation; G6- Clearfil SE Bond without bevel (butt joint); G7- Clearfil SE Bond with bevel preparation; G8- Clearfil SE Bond with chamfer preparation. The adhesive systems were applied according to manufacturers' instructions. Composite resin (Filtek Z250) was incrementally placed in all cavities. After 24 h, the specimens were tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test (fracture strength) and Fisher's exact test (fracture pattern). The confidence level was set at 95% for all tests. Prepared and non-restored teeth showed the worst performance and G4 exhibited the highest fracture strength among all groups (p<0.05). In conclusion, all restorative treatments were able to recover the fracture strength of non-restored teeth to levels similar to those of sound teeth. Using a total-etch adhesive system with bevel preparation significantly improved the resistance to fracture. PMID:20976383

  20. Clinical performance of Class II adhesive restorations in pulpectomized primary molars: 12-month results.

    PubMed

    Zulfikaroglu, Burcu Togay; Atac, Atila Stephan; Cehreli, Zafer C

    2008-01-01

    The purpose of this report was to present the 12-month results of a prospective, randomized study evaluating the clinical and radiographic success rates of Class II adhesive restorations in pulpectomized primary molars. A total of 75 restorations were placed over root canal-treated primary molars, filled with a calcium hydroxide paste. The restorative systems tested were: (1) group 1: amalgam (negative control); (2) group 2: a hybrid resin composite (TPH, Dentsply) with prior acid conditioning and bonding with an etch-and-rinse adhesive (Prime&Bond NT, Dentsply); (3) group 3: a polyacid-modified resin composite (Dyract, Dentsply) bonded with Prime&Bond NT; (4) group 4: Dyract with prior nonrinse conditioner (NRC) treatment and bonding with Prime&Bond NT; and (5) group 5: a polyacid-modified resin composite (F2000) in conjunction with a self-etch adhesive (Prompt-L-Pop, 3M/ESPE). The restorations were evaluated clinically using the modified USPHS/Ryge criteria at 1, 2, 3, 4, 5, 6, 9, and 12 months. Radiographic evaluations were made in accordance with predetermined criteria. During the evaluation period, 12 teeth (group1=4, group2=1, group3=4, group4=3, and group5=2) were extracted due to radiographic evidence of failure. There was no difference between groups regarding the clinical evaluation criteria (P>.05) except marginal discoloration at 9 and 12 months (P<.05). The overall success rate at 12 months was 81% (group 1=73%, group 2=93%, group 3=73%, group 4=80%, and group 5=87%). Teeth restored with the resin composite+total-etch/bonding (group 2), followed by those with F2000+self-etch adhesive (group 5) exhibited the highest clinical and radiographic success rates. Radiographic failures observed beneath failed restorations were strongly suggestive of coronal microleakage. PMID:18505646

  1. The competition between enamel and dentin adhesion within a cavity: an in vitro evaluation of class V restorations.

    PubMed

    Bortolotto, Tissiana; Doudou, Wassila; Kunzelmann, Karl Heinz; Krejci, Ivo

    2012-08-01

    To gain more insight into the consequences of curing contraction within the tooth cavity, we assessed the margin behavior of 12 contemporary restorative systems in class V restorations with margins located on enamel and dentin after mechanical loading and water storage. Mixed class V cavities were prepared on extracted human molars and restored using five etch and rinse and seven self-etch adhesive systems with their corresponding composites. Marginal adaptation was evaluated by using a computer-assisted quantitative marginal analysis in a scanning electron microscope (SEM) on epoxy replicas before, after thermal and mechanical stressing and after 1 year of water storage. The interactions of "testing conditions", "adhesive-composite combination" and "tooth substrate" with "marginal adaptation" were evaluated by two-way ANOVA. Fatigue, stress and storage conditions had significant effects on the marginal adaptation. Only two groups (Optibond FL and G Bond) presented equal percentages of marginal adaptation on enamel and dentin; in the other groups, the rate of degradation was product dependent. All materials tested showed a distinct behavior on enamel and dentin. In addition to mechanical resistance and long-term stability, differences within materials also exist in their ability to simultaneously bond to enamel and dentin. PMID:22015462

  2. Adhesive restorations in the posterior area with subgingival cervical margins: new classification and differentiated treatment approach.

    PubMed

    Veneziani, Marco

    2010-01-01

    The aim of this article is to analyze some of the issues related to the adhesive restoration of teeth with deep cervical and/or subgingival margins in the posterior area. Three different problems tend to occur during restoration: loss of dental substance, detection of subgingival cervical margins, and dentin sealing of the cervical margins. These conditions, together with the presence of medium/large-sized cavities associated with cuspal involvement and absence of cervical enamel, are indications for indirect adhesive restorations. Subgingival margins are associated with biological and technical problems such as difficulty in isolating the working field with a dental dam, adhesion procedures, impression taking, and final positioning of the restoration itself. A new classification is suggested based on two clinical parameters: 1) a technicaloperative parameter (possibility of correct isolation through the dental dam) and 2) a biological parameter (depending on the biologic width). Three different clinical situations and three different therapeutic approaches are identified (1st, 2nd, and 3rd, respectively): coronal relocation of the margin, surgical exposure of the margin, and clinical crown lengthening. The latter is associated with three further operative sequences: immediate, early, or delayed impression taking. The different therapeutic options are described and illustrated by several clinical cases. The surgical-restorative approach, whereby surgery is strictly associated with buildup, onlay preparation, and impression taking is particularly interesting. The restoration is cemented after only 1 week. This approach makes it possible to speed up the therapy by eliminating the intermediate phases associated with positioning the provisional restorations, and with fast and efficient healing of the soft marginal tissue. PMID:20305873

  3. Restoration Materials and Secondary Caries Using an In Vitro Biofilm Model

    PubMed Central

    van de Sande, F.H.; Opdam, N.J.M.; Bronkhorst, E.M.; de Soet, J.J.; Cenci, M.S.; Huysmans, M.C.D.J.N.M.

    2015-01-01

    This in vitro study investigated whether restoration materials and adhesives influence secondary caries formation in gaps using a short-term in vitro biofilm model. Sixty enamel–dentin blocks were restored with 6 different restoration materials with or without adhesives (n = 10 per group) with a gap: 1) Clearfil AP-X composite, 2) Clearfil AP-X composite + SE Bond, 3) Clearfil AP-X composite + ProtectBond, 4) Filtek Silorane composite, 5) Filtek Silorane composite + Silorane System adhesive, or 6) Tytin amalgam. Specimens were subjected to an intermittent 1% sucrose biofilm model for 20 days to create artificial caries lesions. Lesion progression in the enamel–dentin next to the different materials was measured in lesion depth (LD) and mineral loss (ML) using transversal wavelength independent microradiography (T-WIM). A regression analysis was used to compare the LD and ML of the different restoration materials at 4 measurement locations: 1 location at the surface of the enamel, 1 location at the wall of the enamel, and 2 locations at the wall of the dentin. A statistically significant effect of AP-X composite with Protect Bond was found for LD and ML at the WallDentin1 location, leading to less advanced wall lesions. An additional finding was that gap size was also statistically significant at the 2 wall locations in dentin, leading to increasing lesion progression with wider gaps. In conclusion, adhesives can influence wall lesion development in gaps. Protect Bond showed significantly less caries progression compared to bare restoration materials or other adhesives in this short-term in vitro biofilm model. PMID:25297114

  4. New Technique for Evaluating Adhesion Properties between Soft Materials

    NASA Astrophysics Data System (ADS)

    Sato, Takaya; Goto, Motoaki; Nakano, Ken; Suzuki, Atsushi

    2005-11-01

    A new, simple apparatus for measuring the surface adhesion properties of soft materials was designed, where the adhesion force of a point contact between soft materials and the total energy required to separate the contact can be measured using the springs of phosphor-bronze thin plates with strain gauges. The adhesion between swollen hydrogels was studied here by this simple technique in air at room temperature. The gels used in the present preliminary experiments were poly(sodium acrylate) hydrogels physically cross-linked by aluminum ions. The adhesion force and the separation energy showed a power-law increase with separation velocity. The apparatus was applied to evaluate the adhesion properties of seven anti-inflammatory analgesic cataplasms on the market. It was found that the easiness to separate (rank of adhesion force and the separation energy) was consistent with the results of those obtained by organoleptic evaluations.

  5. Effect of curing unit and adhesive system on marginal adaptation of composite restorations.

    PubMed

    Casselli, Denise Sa Maia; Faria-e-Silva, Andre Luis; Casselli, Henrique; Martins, Luis Roberto Marcondes

    2012-01-01

    This study sought to evaluate how a curing unit and adhesive system affected the marginal adaptation of resin composite restorations. Class V cavities were prepared in bovine teeth with a gingival margin in dentin and an incisal margin in enamel. The cavities were restored with a micro-hybrid resin composite using one of four adhesives: Single Bond 2, Prime & Bond NT, Clearfil SE Bond, Xeno IV. The light-activations were performed using a quartz-tungsten-halogen (QTH) lamp or a second-generation light-emitting diode (LED). Restorations were finished and polished and epoxy replicas were prepared. Marginal adaptation was analyzed by using scanning electronic microscopy (magnification 500X). The widest gaps in each margin were recorded, and data were submitted to Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (α = 0.05). Differences between the adhesives were observed only when the dentin margins were evaluated: Clearfil SE Bond demonstrated better marginal adaptation than Prime & Bond NT or Single Bond 2 (which demonstrated the widest gaps in the dentin margin). The type of curing unit only affected the results for Xeno IV when the enamel margin was analyzed; the LED lamp promoted smaller gaps than the QTH lamp. PMID:23220321

  6. New restoration and direct pulp capping systems using adhesive composite resin.

    PubMed

    Kashiwada, T; Takagi, M

    1991-12-01

    There have been many arguments on the irritating mechanisms of the composite resin on the dental pulp. While the direct irritative effect of the resin has been preferred, some authors considered that the marginal microleakage and the resulting bacterial infection play a more important role in inducing the complicating pulp irritation. We developed a new filling technique, called the direct inlay restoration method, which could prevent the marginal leakage associated with the polymerization shrinkage of the adhesive composite resin. In this study, we tried to apply our method clinically. None of the 440 cases which were filled with the adhesive composite resin and 60 cases out of 64 cases in which the pulps were directly capped with the adhesive composite resin developed any signs and symptoms of pulp irritation. The other 4 cases developed signs of pulp irritation. Two of those 4 cases were pulpectomized due to spontaneous pain and the other 2 cases turned out to be well after re-restoration. With the informed consent of the patients, the direct pulp capping using the adhesive composite resin was experimentally performed on 6 caries-free 3rd molars and the histopathological examination of these capped molars revealed that neither significant degenerative nor inflammatory changes were brought about in the dental pulp. These clinical and histopathological observation suggest that the dental pulp irritation after resin filling is not induced by the composite resin itself. PMID:1764760

  7. High capacity, easy release adhesives from renewable materials.

    PubMed

    Bartlett, Michael D; Crosby, Alfred J

    2014-06-01

    Reversible adhesives composed of renewable materials are presented which achieve high force capacities (810 N) while maintaining easy release (∼ 0.25 N) and reusability. These simple, non-tacky adhesives consist of natural rubber impregnated into stiff natural fiber fabrics, including cotton, hemp, and jute. This versatile approach enables a clear method for designs of environmentally-responsible, reversible adhesives for a wide variety of applications. PMID:24504650

  8. 3D-finite element analyses of cusp movements in a human upper premolar, restored with adhesive resin-based composites.

    PubMed

    Ausiello, P; Apicella, A; Davidson, C L; Rengo, S

    2001-10-01

    The combination of diverse materials and complex geometry makes stress distribution analysis in teeth very complicated. Simulation in a computerized model might enable a study of the simultaneous interaction of the many variables. A 3D solid model of a human maxillary premolar was prepared and exported into a 3D-finite element model (FEM). Additionally, a generic class II MOD cavity preparation and restoration was simulated in the FEM model by a proper choice of the mesh volumes. A validation procedure of the FEM model was executed based on a comparison of theoretical calculations and experimental data. Different rigidities were assigned to the adhesive system and restorative materials. Two different stress conditions were simulated: (a) stresses arising from the polymerization shrinkage and (b) stresses resulting from shrinkage stress in combination with vertical occlusal loading. Three different cases were analyzed: a sound tooth, a tooth with a class II MOD cavity, adhesively restored with a high (25 GPa) and one with a low (12.5GPa) elastic modulus composite. The cusp movements induced by polymerization stress and (over)-functional occlusal loading were evaluated. While cusp displacement was higher for the more rigid composites due to the pre-stressing from polymerization shrinkage, cusp movements turned out to be lower for the more flexible composites in case the restored tooth which was stressed by the occlusal loading. This preliminary study by 3D FEA on adhesively restored teeth with a class II MOD cavity indicated that Young's modulus values of the restorative materials play an essential role in the success of the restoration. Premature failure due to stresses arising from polymerization shrinkage and occlusal loading can be prevented by proper selection and combination of materials. PMID:11522306

  9. Antibacterial dental restorative materials: a state-of-the-art review.

    PubMed

    Chen, Liang; Shen, Hong; Suh, Byoung In

    2012-12-01

    This review presents an updated knowledge on the antibacterial dental restorative materials and their performance clinically and in the laboratory. A search of English peer-reviewed dental literature over the last 30 years from PubMed and MEDLINE databases was conducted, and the key words included antibacterial, antimicrobial, dental, primer, adhesive, bonding agent, cement, and composite. Titles and abstracts of the articles listed from search results were reviewed and evaluated for relevancy. In summary, the incorporation of an appropriate amount of antibacterial agent provided dental restorative materials (dental bonding agents, resin composites, resin cements, glass-ionomer cements) antibacterial activity without significantly influencing mechanical properties. PMID:23409624

  10. The effect of thermocycling on the bonding of different restorative materials to access opening through porcelain fused to metal restorations

    PubMed Central

    AL-Moaleem, Mohammed M.; Shah, Farhan Khalid; Khan, Nausheen Saied

    2011-01-01

    PURPOSE Porcelain fused to metal (PFM) crowns provide the best treatment option for teeth that have a large or defective restoration. More than 20% of teeth with PFM crowns or bridges require non-surgical root canal treatment (NSRCT). This may be due to the effect of restorative procedures and the possible leakage of bacteria and or their by-products, which leads to the demise of the tooth pulp. Thus, this study was planned to compare the ability of the restorative materials to seal perforated PFM specimens. MATERIALS AND METHODS The study evaluates the ability of amalgam, composite or compomer restorative materials to close perforated PFM specimen's in-vitro. Ninety PFM specimens were constructed using Ni-Cr alloys and feldspathic porcelain, and then they were divided into 3 groups: amalgam (A), composite + Exite adhesive bond (B) and compomer + Syntac adhesive bond (C). All the PFM samples were embedded in an acrylic block to provide complete sealing of the hole from the bottom side. After the aging period, each group was further divided into 3 equal subgroups according to the thermocycling period (one week for 70 cycles, one month for 300 cycles and three months for 900 cycles). Each subgroup was put into containers containing dye (Pelikan INK), one maintained at 5℃ and the other at 55℃, each cycle for 30 sec time. The data obtained was analyzed by SPSS, 2006 using one way ANOVA test and student t-test and significant difference level at (P<.01). RESULTS The depth of dye penetration was measured at the interfaces of PFM and filling materials using Co-ordinate Vernier Microscope. The lowest levels of the dye penetration for the three groups, as well as subgroups were during the first week. The values of dye leakage had significantly increased by time intervals in subgroups A and C. CONCLUSION It was seen that amalgam showed higher leakage than composite while compomer showed the lowest level of leakage. PMID:22259701

  11. Adhesion layer for etching of tracks in nuclear trackable materials

    DOEpatents

    Morse, Jeffrey D.; Contolini, Robert J.

    2001-01-01

    A method for forming nuclear tracks having a width on the order of 100-200 nm in nuclear trackable materials, such as polycarbonate (LEXAN) without causing delamination of the LEXAN. The method utilizes an adhesion film having a inert oxide which allows the track to be sufficiently widened to >200 nm without delamination of the nuclear trackable materials. The adhesion film may be composed of a metal such as Cr, Ni, Au, Pt, or Ti, or composed of a dielectric having a stable surface, such as silicon dioxide (SiO.sub.2), silicon nitride (SiN.sub.x), and aluminum oxide (AlO). The adhesion film can either be deposited on top of the gate metal layer, or if the properties of the adhesion film are adequate, it can be used as the gate layer. Deposition of the adhesion film is achieved by standard techniques, such as sputtering or evaporation.

  12. A useful and non-invasive microanalysis method for dental restoration materials

    NASA Astrophysics Data System (ADS)

    Hosoki, M.; Satsuma, T.; Nishigawa, K.; Takeuchi, H.; Asaoka, K.

    2012-12-01

    The elemental analysis of intraoral dental restorations provides considerable information for the treatment of dental metal allergy. Elemental analyses require specific instruments and complicated procedures, so this examination is not commonly carried out in private dental clinics. We describe a novel, simple and useful micro-analytical method for dental metal restorations. Micro metal dust was obtained by polishing the surface of restorative metal material with an unused silicone point (SUPER-SNAP). The metal dust on the silicone point was then rubbed onto adhesive tape, and this tape was covered with polyethylene film. The amount of metal dust material was <20 μg. An energy dispersive X-ray fluorescence spectrometer was used to carry out the elementary analysis of the metal dust on the polyethylene film. Three types of dental metal alloy materials of known components were examined. The results of elementary analyses were compared with the specifications provided by the manufacturer. The same procedure was carried out for three dental metal restorations of an adult female volunteer in vivo. The results of elemental analyses for five alloy materials exactly matched the product specification. Three metal samples obtained from intraoral restoration were also available for elemental analyses. The distinct advantage of this method is that it enables sample extraction without an invasive effect for the restoration. The metal sample is in a polyethylene film, so it is easy to mail it for inspection at specialist institutes yet it can be also be used in general dental clinics.

  13. Evaluation of sealing ability two self-etching adhesive systems and a glass ionomer lining LC under composite restoration in primary tooth: An in vitro study

    PubMed Central

    Pragasam, Ananda Xavier; Duraisamy, Vinola; Nayak, Ullal Anand; Reddy, Venugopal; Rao, Arun Prasad

    2015-01-01

    Aims and Objectives: To evaluate the sealing ability of two self-etching adhesive systems and glass ionomer cement (GIC) lining Light cure (LC) under composite restorations in primary teeth. Materials and Methods: Class V cavities are prepared on the cervical third of the facial and lingual surfaces of primary molars. The specimens are then assigned into four experimental groups. The restored primary molars are stored in distilled water and subjected to thermocycling. Each section was examined using a stereomicroscope to assess dye penetration at the margin of the restoration and evaluated via pictures. Statistical Analysis Used: The degree of microleakage was analyzed using Kruskal–Wallis test and the intergroup significance by multiple comparison analysis. Results: The mean rank of the groups are Group I (Adper Prompt™ + Z−100) 19.44, Group II (UniFil BOND + Solare) 5.38, Group III (GIC lining LC + Z−100) 20.06, and Group IV (GIC lining LC + Solare) 21.13 with the P < 0.001. Conclusion: Composite resin restorations bonded with two-step self-etching adhesive system (UniFil Bond) exhibited lesser microleakage than one-step self-etching adhesive system (Adperprompt™) in primary teeth. PMID:26538910

  14. Material and clinical considerations for full-coverage indirect restorations.

    PubMed

    Martin, Margaret P

    2012-11-01

    Because dental ceramics have been used for decades and continuously improved over the years, there is a plethora of information regarding their material characteristics, applications, and contraindications. Each restorative ceramic material demonstrates benefits and disadvantages, making it difficult for dentists to research, retain, and apply the ideal material for individual restorations and/or combination cases. This article outlines the applications and benefits of dental ceramics in general and examines and reviews the current ceramic alternatives available for restorative dentistry today. It also discusses the material composition and properties of a recently introduced new classification of indirect material: resin nano-ceramic. PMID:23577553

  15. Shear adhesion strength of thermoplastic gecko-inspired synthetic adhesive exceeds material limits.

    PubMed

    Gillies, Andrew G; Fearing, Ronald S

    2011-09-20

    Natural gecko array wearless dynamic friction has recently been reported for 30,000 cycles on a smooth substrate. Following these findings, stiff polymer gecko-inspired synthetic adhesives have been proposed for high-cycle applications such as robot feet. Here we examine the behavior of high-density polyethylene (HDPE) and polypropylene (PP) microfiber arrays during repeated cycles of engagement on a glass surface, with a normal preload of less than 40 kPa. We find that fiber arrays maintained 54% of the original shear stress of 300 kPa after 10,000 cycles, despite showing a marked plastic deformation of fiber tips. This deformation could be due to shear-induced plastic creep of the fiber tips from high adhesion forces, adhesive wear, or thermal effects. We hypothesize that a fundamental material limit has been reached for these fiber arrays and that future gecko synthetic adhesive designs must take into account the high adhesive forces generated to avoid damage. Although the synthetic material and natural gecko arrays have a similar elastic modulus, the synthetic material does not show the same wear-free dynamic friction as the gecko. PMID:21848321

  16. Clinical challenges and the relevance of materials testing for posterior composite restorations.

    PubMed

    Sarrett, David C

    2005-01-01

    Posterior composite restorations have been in use for approximately 30 years. The early experiences with this treatment indicated there were more clinical challenges and higher failure rates than amalgam restorations. Since the early days of posterior composites, many improvements in materials, techniques, and instruments for placing these restorations have occurred. This paper reviews what is known regarding current clinical challenges with posterior composite restorations and reviews the primary method for collecting clinical performance data. This review categorizes the challenges as those related to the restorative materials, those related to the dentist, and those related to the patient. The clinical relevance of laboratory tests is discussed from the perspective of solving the remaining clinical challenges of current materials and of screening new materials. The clinical problems related to early composite materials are no longer serious clinical challenges. Clinical data indicate that secondary caries and restoration fracture are the most common clinical problems and merit further investigation. The effect of the dentist and patient on performance of posterior composite restorations is unclear and more clinical data from hypothesis-driven clinical trials are needed to understand these factors. Improvements in handling properties to ensure void-free placement and complete cure should be investigated to improve clinical outcomes. There is a general lack of data that correlates clinical performance with laboratory materials testing. A proposed list of materials tests that may predict performance in a variety of clinical factors is presented. Polymerization shrinkage and the problems that have been attributed to this property of composite are reviewed. There is a lack of evidence that indicates polymerization shrinkage is the primary cause of secondary caries. It is recommended that composite materials be developed with antibacterial properties as a way of

  17. Sealing of adhesive systems in ferric sulfate-contaminated dentinal margins in class V composite resin restorations.

    PubMed

    Shadman, Niloofar; Farzin Ebrahimi, Shahram; Mollaie, Najmeh

    2016-01-01

    Background. Hemostatic agents are applied to prepare an isolated bleeding-free condition during dental treatments and can influence adhesive restorations. This study evaluated the effect of a hemostatic agent (ViscoStat) on microleakage of contaminated dentinal margin of class V composite resin restorations with three adhesives. Methods. Sixty freshly extracted human molars were selected and class V cavities (3×3×1.5 mm) were prepared on buccal and lingual surfaces. Gingival margins of the cavities were placed below the cementoenamel junction. The teeth were divided into six groups randomly. The adhesives were Excite, AdheSE and AdheSE One. In three groups, the gingival walls of the cavities were contaminated with ViscoStat and then rinsed. The cavities were restored with composite resin and light-cured. After storage in distilled water (37°C) for 24 hours and polishing, the samples were thermocycled and sealed with nail varnish. Then they were stored in 1% basic fuchsin for 24 hours, rinsed and mounted in self-cured acryl resin, followed by sectioning buccolingually. Dye penetration was observed under a stereomicroscope and scored. Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U tests. P<0.05 was set as the level of significance. Results. Only in the Excite group, contamination did not have adverse effects on dentin microleakage (P > 0.05). In the contaminated groups, Excite had significantly less microleakage than the others (P = 0.003). AdheSE and AdheSE One did not exhibit significant difference in microleakage (P > 0.05). Conclusion. ViscoStat hemostatic agent increased dentinal microleakage in AdheSE and AdheSE One adhesives with no effect on Excite. PMID:27092210

  18. Sealing of adhesive systems in ferric sulfate-contaminated dentinal margins in class V composite resin restorations

    PubMed Central

    Shadman, Niloofar; Farzin Ebrahimi, Shahram; Mollaie, Najmeh

    2016-01-01

    Background. Hemostatic agents are applied to prepare an isolated bleeding-free condition during dental treatments and can influence adhesive restorations. This study evaluated the effect of a hemostatic agent (ViscoStat) on microleakage of contaminated dentinal margin of class V composite resin restorations with three adhesives. Methods. Sixty freshly extracted human molars were selected and class V cavities (3×3×1.5 mm) were prepared on buccal and lingual surfaces. Gingival margins of the cavities were placed below the cementoenamel junction. The teeth were divided into six groups randomly. The adhesives were Excite, AdheSE and AdheSE One. In three groups, the gingival walls of the cavities were contaminated with ViscoStat and then rinsed. The cavities were restored with composite resin and light-cured. After storage in distilled water (37°C) for 24 hours and polishing, the samples were thermocycled and sealed with nail varnish. Then they were stored in 1% basic fuchsin for 24 hours, rinsed and mounted in self-cured acryl resin, followed by sectioning buccolingually. Dye penetration was observed under a stereomicroscope and scored. Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U tests. P<0.05 was set as the level of significance. Results. Only in the Excite group, contamination did not have adverse effects on dentin microleakage (P > 0.05). In the contaminated groups, Excite had significantly less microleakage than the others (P = 0.003). AdheSE and AdheSE One did not exhibit significant difference in microleakage (P > 0.05). Conclusion. ViscoStat hemostatic agent increased dentinal microleakage in AdheSE and AdheSE One adhesives with no effect on Excite. PMID:27092210

  19. Development of Native Plant Materials for Use in Restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of native plant materials for restoration demands that close attention be paid to the expectations of the specialized customer base of restoration practitioners. Native and introduced plants are not biologically different, but they are usually very different in how they are marketed...

  20. Ecologically appropriate plant materials for functional restoration of rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecosystems of rangelands targeted for restoration have often been modified, hindering restoration efforts. WEhile local adaptation has long been used as an argument for the exclusive use of local plant materials, recent meta-analysis results indicate that general adaptation across a variety of envi...

  1. Cervical margin integrity of Class II resin composite restorations in laser- and bur-prepared cavities using three different adhesive systems.

    PubMed

    Oskoee, Parnian Alizadeh; Kimyai, Soodabeh; Ebrahimi Chaharom, Mohammad Esmaeel; Rikhtegaran, Sahand; Pournaghi-Azar, Fatemeh

    2012-01-01

    One of the challenges in durability of posterior tooth-colored restorative materials is polymerization shrinkage, which results in gap formation between the restoration and tooth structure. The aim of the present study was to investigate marginal adaptation of Class II composite restorations using a self-etching and two etch-and-rinse adhesive systems in cavities prepared either with bur or Er,Cr:YSGG laser. A total of 45 extracted sound human premolars were selected. In each tooth, mesial and distal Class II cavities were prepared either by a diamond bur or by Er,Cr:YSGG laser with the margins 1 mm apical to the cemento-enamel junction. Then the teeth were randomly divided into three groups of 15 each, according to the type of the adhesive system used (Single Bond, Single Bond 2, and Adper Easy One adhesive systems). Subsequent to restoring the teeth, the specimens were subjected to thermal cycling between 5 ± 2°C and 55 ± 2°C for 500 cycles and were then cut longitudinally into two halves using a diamond disk. Marginal adaptation was evaluated using a stereomicroscope, and the values for gap widths were obtained in micrometers. Data were analyzed using two-factor analysis of variance and post hoc tests. There were statistically significant differences in mean marginal gap widths between the adhesive type and preparation groups (p<0.05). The interfacial gap width in bur-prepared cavities was significantly less than that in laser-prepared cavities, and the lowest gap width was observed in Adper Easy One regardless of the type of the preparation. PMID:22313277

  2. Effect of lining with a flowable composite on internal adaptation of direct composite restorations using all-in-one adhesive systems.

    PubMed

    Yahagi, Chika; Takagaki, Tomohiro; Sadr, Alireza; Ikeda, Masaomi; Nikaido, Toru; Tagami, Junji

    2012-01-01

    The purpose of this study was to evaluate the effect of lining with a flowable composite on internal adaptation of composite restorations using three all-in-one adhesive systems; Bond Force (BF), G-Bond Plus (GP), and OptiBond All-in-one (OP), and a two-step self-etching adhesive system; Clearfil SE Bond (SE). They were applied to each cylindrical cavity prepared on the human dentin. The cavity surface was lined with/without a flowable resin composite prior to filling with a resin composite (FL/NL). After water storage for 24 h, the specimens were sectioned and polished, and internal adaptation of the restorations was assessed using a confocal laser scanning microscopy. For SE, a perfect cavity adaptation was recognized in both FL and NL. For BF, GP and OP, cavity adaptation was material dependent in NL, whereas no gap formation was observed in FL. However, voids formation was observed at the composite-adhesive-dentin interface in every all-in-one adhesive system. PMID:22673475

  3. Chairside resin-based provisional restorative materials for fixed prosthodontics.

    PubMed

    Strassler, Howard E; Lowe, Robert A

    2011-01-01

    Provisional restorations are vital to fixed prosthodontics treatment, providing an important diagnostic function while in place. In addition to protecting the prepared teeth, provisionalization enables clinicians to refine biologic and biomechanical issues before the final restoration is fabricated. Adjustments can be made in the provisional restoration to achieve both the clinician's and patient's desired results. The fabrication of temporary restorations requires that clinicians be proficient with a variety of materials and techniques that can be used to make well-adapted and functional provisionals. There are many material choices available to temporize a single crown as well as multi-unit fixed partial dentures, and the selection of provisional materials should be made based on a case-by-case evaluation. This article provides a review of polymeric resin provisional materials. PMID:22167927

  4. Adhesion of liquids to porous materials and fibers

    NASA Astrophysics Data System (ADS)

    Trofimov, Artem

    This research is centered on the analysis of adhesion properties of porous materials and fibers of elliptical shapes. Composites are a unique class of materials having properties, which could not be achieved by either of the constituent materials alone. Composites with porous filler are put into service in buildings, roads, bridges, etc. Fiber-reinforced composites are actively involved in flight vehicles, automobiles, boats, and dozens of other products. In the first part of this study we developed a procedure for evaluation of adhesion of liquids to porous solids, where water, hexadecane and asphalt binder and different rocks were studied to illustrate the methodology. An experimental protocol to evaluate the work of adhesion, a characteristic thermodynamic parameter of the liquid/porous solid pair, was discussed and a mathematical model describing the kinetics of liquid penetration into inhomogeneous porous material was developed and used for interpretation of the experiments. The second part is devoted to the analysis of interactions of liquids with circular and elliptical wires. The behavior of menisci embracing the fiber in the capillary rise experiment was investigated. In particular, we study the profiles of the contact line around cylinders, contact angle, and the work of adhesion of a set of different liquids. Compared to the circular wires, elliptical wires produced taller menisci, hence the wetted area increases. It is expected that the kinetics of resin impregnation into a preforms made of elliptical fibers will significantly change.

  5. Supramolecular polymer adhesives: advanced materials inspired by nature.

    PubMed

    Heinzmann, Christian; Weder, Christoph; de Espinosa, Lucas Montero

    2016-01-21

    Due to their dynamic, stimuli-responsive nature, non-covalent interactions represent versatile design elements that can be found in nature in many molecular processes or materials, where adaptive behavior or reversible connectivity is required. Examples include molecular recognition processes, which trigger biological responses or cell-adhesion to surfaces, and a broad range of animal secreted adhesives with environment-dependent properties. Such advanced functionalities have inspired researchers to employ similar design approaches for the development of synthetic polymers with stimuli-responsive properties. The utilization of non-covalent interactions for the design of adhesives with advanced functionalities such as stimuli responsiveness, bonding and debonding on demand capability, surface selectivity or recyclability is a rapidly emerging subset of this field, which is summarized in this review. PMID:26203784

  6. Fracture resistance of endodontically treated teeth restored with a bulkfill flowable material and a resin composite

    PubMed Central

    Isufi, Almira; Plotino, Gianluca; Grande, Nicola Maria; Ioppolo, Pietro; Testarelli, Luca; Bedini, Rossella; Al-Sudani, Dina; Gambarini, Gianluca

    2016-01-01

    Summary Aim To determine and compare the fracture resistance of endodontically treated teeth restored with a bulk fill flowable material (SDR) and a traditional resin composite. Methods Thirty maxillary and 30 mandibular first molars were selected based on similar dimensions. After cleaning, shaping and filling of the root canals and adhesive procedures, specimens were assigned to 3 subgroups for each tooth type (n=10): Group A: control group, including intact teeth; Group B: access cavities were restored with a traditional resin composite (EsthetX; Dentsply-Italy, Rome, Italy); Group C: access cavities were restored with a bulk fill flowable composite (SDR; Dentsply-Italy), except 1.5 mm layer of the occlusal surface that was restored with the same resin composite as Group B. The specimens were subjected to compressive force in a material static-testing machine until fracture occurred, the maximum fracture load of the specimens was measured (N) and the type of fracture was recorded as favorable or unfavorable. Data were statistically analyzed with one-way analysis of variance (ANOVA) and Bonferroni tests (P<0.05). Results No statistically significant differences were found among groups (P<0.05). Fracture resistance of endodontically treated teeth restored with a traditional resin composite and with a bulk fill flowable composite (SDR) was similar in both maxillary and mandibular molars and showed no significant decrease in fracture resistance compared to intact specimens. Conclusions No significant difference was observed in the mechanical fracture resistance of endodontically treated molars restored with traditional resin composite restorations compared to bulk fill flowable composite restorations. PMID:27486505

  7. A novel approach to implant screw-retained restorations: adhesive combination between zirconia frameworks and monolithic lithium disilicate.

    PubMed

    Fabbri, Giacomo; Sorrentino, Roberto; Brennan, Myra; Cerutti, Antonio

    2014-01-01

    The use of zirconia is an esthetic alternative to metal for implant-supported frameworks, and it has increased primarily for its high biocompatibility, low bacterial surface adhesion, high flexural strength and high mechanical features. The zirconia frameworks in fixed prosthetic restorations that are supported by implants is commonly covered with hand-layered overlay porcelain. This technical procedure is highly esthetic but it can cause some complications, such as porcelain fractures. The purpose of this article is to introduce an innovative approach to create an esthetic fixed ceramic implant restoration to minimize and facilitate the repair of the mechanical complications, by combining the adhesive-cementation of lithium disilicate full coverage restorations on implant screw-retained zirconia frameworks. PMID:25289384

  8. Nanotechnology-based restorative materials for dental caries management

    PubMed Central

    Melo, Mary A.S.; Guedes, Sarah F.F.; Xu, Hockin H.K.; Rodrigues, Lidiany K.A.

    2013-01-01

    Nanotechnology has been applied to dental materials as an innovative concept for the development of materials with better properties and anticaries potential. In this review we discuss the current progress and future applications of functional nanoparticles incorporated in dental restorative materials as useful strategies to dental caries management. We also overview proposed antimicrobial and remineralizing mechanisms. Nanomaterials have great potential to decrease biofilm accumulation, inhibit the demineralization process, to be used for remineralizing tooth structure, and to combat caries-related bacteria. These results are encouraging and open the doors to future clinical studies that will allow the therapeutic value of nanotechnology-based restorative materials to be established. PMID:23810638

  9. Effects of Material Properties on Bacterial Adhesion and Biofilm Formation.

    PubMed

    Song, F; Koo, H; Ren, D

    2015-08-01

    Adhesion of microbes, such as bacteria and fungi, to surfaces and the subsequent formation of biofilms cause multidrug-tolerant infections in humans and fouling of medical devices. To address these challenges, it is important to understand how material properties affect microbe-surface interactions and engineer better nonfouling materials. Here we review the recent progresses in this field and discuss the main challenges and opportunities. In particular, we focus on bacterial biofilms and review the effects of surface energy, charge, topography, and stiffness of substratum material on bacterial adhesion. We summarize how these surface properties influence oral biofilm formation, and we discuss the important findings from nondental systems that have potential applications in dental medicine. PMID:26001706

  10. Evaluation of MMA-4-META-TBB resin as a dental adhesive material.

    PubMed

    Kuo, Y S

    1984-04-01

    A new adhesive resin containing a reactive monomer, 4-methacryloxyethyl trimellitate anhydride (4-META) was prepared, and its application to hard tooth tissues and metals was studied. Scanning electron microscopy showed that the average length of 4-META resin tags in enamel and dentin was 22 mu and 40 mu respectively. The tensile adhesive strength between 4-META resin and enamel was about 130 kg/cm2 after etching with 65% phosphoric acid. Its bond strength to dentin treated with a cleaning solution of 10% citric acid and 3% ferric chloride was about 190 kg/cm2. In precious alloys heated at 500 degrees C for 5-10 minutes, a bond strength of more than 100 kg/cm2 was obtained. The precious alloys containing Au, Ag, Pt and Cu should be selected especially for dental restorations. In polished non-precious alloys, the bond strength was greater than 100 kg/cm2. If non-precious alloys were oxidized with HNO3, the bond strength increased to 150-200 kg/cm2. The results suggest that the nickel-chromium alloy used in fixed prosthodontics must be treated chemically before adhesion with 4-META resin, but cobalt-chromium alloy used in removable partial dentures bonds well with 4-META resin without chemical treatment. In conclusion, MMA-4-META-TBB resin seems to be a promising adhesive material in dentistry. PMID:6571588

  11. Interpreting finite element results for brittle materials in endodontic restorations

    PubMed Central

    2011-01-01

    Background Finite element simulation has been used in last years for analysing the biomechanical performance of post-core restorations in endodontics, but results of these simulations have been interpreted in most of the works using von Mises stress criterion. However, the validity of this failure criterion for brittle materials, which are present in these restorations, is questionable. The objective of the paper is to analyse how finite element results for brittle materials of endodontic restorations should be interpreted to obtain correct conclusions about the possible failure in the restoration. Methods Different failure criteria (Von Mises, Rankine, Coulomb-Mohr, Modified Mohr and Christensen) and material strength data (diametral tensile strength and flexural strength) were considered in the study. Three finite element models (FEM) were developed to simulate an endodontic restoration and two typical material tests: diametral tensile test and flexural test. Results Results showed that the Christensen criterion predicts similar results as the Von Mises criterion for ductile components, while it predicts similar results to all other criteria for brittle components. The different criteria predict different failure points for the diametral tensile test, all of them under multi-axial stress states. All criteria except Von Mises predict failure for flexural test at the same point of the specimen, with this point under uniaxial tensile stress. Conclusions From the results it is concluded that the Christensen criterion is recommended for FEM result interpretation in endodontic restorations and that the flexural test is recommended to estimate tensile strength instead of the diametral tensile test. PMID:21635759

  12. Adhesion

    MedlinePlus

    ... adhesions Ovarian cyst References Munireddy S, Kavalukas SL, Barbul A. Intra-abdominal healing: gastrointestinal tract and adhesions. Surg Clin N Am Kulaylat MN, Dayton, MT. Surgical complications. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, ...

  13. Provisional materials: key components of interim fixed restorations.

    PubMed

    Perry, Ronald D; Magnuson, Britta

    2012-01-01

    Clinicians have many choices of provisional materials from which to choose when fabricating interim fixed restorations. While traditional materials are still in use today, temporary materials are continuously being updated and improved upon. In addition to the functional necessities required of the provisional material, it must also provide esthetic value for the patient. This article provides an overview of provisional materials, including newer bis-acryls that have helped eliminate some of the challenges associated with traditional acrylic materials. Composite resin preformed crowns for single-unit provisional applications are also discussed, along with CAD/CAM-fabricated materials. Regardless of the material selected, a provisional restoration must maintain and protect the underlying tooth structure from ill effects. PMID:22432178

  14. The effect of oxalate desensitizers on the microleakage of resin composite restorations bonded by etch and rinse adhesive systems.

    PubMed

    Shafiei, Fereshteh; Motamedi, Mehran; Alavi, Ali Asghar; Namvar, Babak

    2010-01-01

    This in vitro study evaluated the effect of an oxalate desensitizer (OX) on the marginal microleakage of resin composite restorations bonded by two three-step and two two-step etch and rinse adhesives. Class V cavities were prepared on the buccal surfaces of 126 extracted premolars at the cementoenamel junction and randomly divided into nine groups of 14 each. In the control groups (1-4), four adhesives were applied, respectively, including Adper Scotchbond Multi-Purpose (SBMP), Optibond FL (OBFL), One-Step Plus (OS) and Excite (EX). In the experimental groups (5-8), the same adhesives, in combination with OX (BisBlock), were applied. And, in one group, OX was applied without any adhesive, as the negative control group (9). All the groups were restored with a resin composite. After 24 hours of storage in distilled water and thermocycling, the samples were placed in 1% methylene blue dye solution. The dye penetration was evaluated using a stereomicroscope. The data were analyzed using non-parametric tests. The OX application, in combination with OBFL and EX, resulted in significantly increasing microleakage at the gingival margins (p < 0.05), while it had no effect on OS and SBMP (p > 0.05). At the occlusal margins, no significant difference in microleakage was observed after OX application for each of four adhesives (p > 0.05). PMID:21180008

  15. 49 CFR 173.173 - Paint, paint-related material, adhesives, ink and resins.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Paint, paint-related material, adhesives, ink and... Than Class 1 and Class 7 § 173.173 Paint, paint-related material, adhesives, ink and resins. (a) When..., paint-related material, adhesives, ink and resins must be packaged as follows: (1) As prescribed...

  16. 49 CFR 173.173 - Paint, paint-related material, adhesives, ink and resins.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Paint, paint-related material, adhesives, ink and... Than Class 1 and Class 7 § 173.173 Paint, paint-related material, adhesives, ink and resins. (a) When..., paint-related material, adhesives, ink and resins must be packaged as follows: (1) As prescribed...

  17. Recent Advances and Developments in Composite Dental Restorative Materials

    PubMed Central

    Cramer, N.B.; Stansbury, J.W.; Bowman, C.N.

    2011-01-01

    Composite dental restorations represent a unique class of biomaterials with severe restrictions on biocompatibility, curing behavior, esthetics, and ultimate material properties. These materials are presently limited by shrinkage and polymerization-induced shrinkage stress, limited toughness, the presence of unreacted monomer that remains following the polymerization, and several other factors. Fortunately, these materials have been the focus of a great deal of research in recent years with the goal of improving restoration performance by changing the initiation system, monomers, and fillers and their coupling agents, and by developing novel polymerization strategies. Here, we review the general characteristics of the polymerization reaction and recent approaches that have been taken to improve composite restorative performance. PMID:20924063

  18. Finite element calculation of residual stress in dental restorative material

    NASA Astrophysics Data System (ADS)

    Grassia, Luigi; D'Amore, Alberto

    2012-07-01

    A finite element methodology for residual stresses calculation in dental restorative materials is proposed. The material under concern is a multifunctional methacrylate-based composite for dental restorations, activated by visible light. Reaction kinetics, curing shrinkage, and viscoelastic relaxation functions were required as input data on a structural finite element solver. Post cure effects were considered in order to quantify the residual stresses coming out from natural contraction with respect to those debited to the chemical shrinkage. The analysis showed for a given test case that residual stresses frozen in the dental restoration at uniform temperature of 37°C are of the same order of magnitude of the strength of the dental composite material per se.

  19. Adhesive material transfer in the erosion of an aluminum alloy

    NASA Technical Reports Server (NTRS)

    Salik, J.; Brainard, W. A.

    1979-01-01

    In order to study the basic mechanisms of erosion, hardened steel balls were shot into annealed 6061 Al alloy targets at velocity of up to 150 m/sec. The projectiles were collected and examined by a scanning electron microscope combined with energy-dispersive X-ray analyzer and it was found that target material in substantial amounts is adhesively transferred to the projectile. The transferred material forms on the projectile surface a layer the thickness of which increases with increases in impact velocity.

  20. Adhesion and Long-Term Barrier Restoration of Intrinsic Self-Healing Hybrid Sol-Gel Coatings.

    PubMed

    Abdolah Zadeh, Mina; van der Zwaag, Sybrand; Garcia, Santiago J

    2016-02-17

    Self-healing polymeric coatings aiming at smart and on-demand protection of metallic substrates have lately attracted considerable attention. In the present paper, the potential application of a dual network hybrid sol-gel polymer containing reversible tetrasulfide groups as a protective coating for the AA2024-T3 substrate is presented. Depending on the constituent ratio, the developed polymer exhibited a hydrophobic surface, high adhesion strength, and an effective long-term corrosion protection in 0.5 M NaCl solution. Upon thermal treatment, the healable hybrid sol-gel coating demonstrated full restoration of the barrier properties as well as recovery of the coating adhesion and surface properties (e.g., hydrophobicity and surface topology) necessary for lifetime extension of corrosion protective coatings. Excellent long-term barrier restoration of the coating was only obtained if the scratch width was less than the coating thickness. PMID:26780101

  1. Influence of Photoactivation Source on Restorative Materials and Enamel Demineralization

    PubMed Central

    Popoff, Josiane Marques de Sena; Rodrigues, José Augusto; Aras, Wanessa Maria De Freitas

    2014-01-01

    Abstract Objective: The objective of this study was to evaluate the influence of the photoactivation source on the polymerization depth of restorative materials and its effects on resistance to enamel demineralization. Background data: Argon-ion laser (AL) irradiation itself provides a reduced depth of caries lesions in sound enamel. Methods: Eighteen human teeth were sectioned into 36 blocks and distributed into two groups according to the respective restorative material: resin-modified glass ionomer material (RMGI) (Vitremer-3M ESPE; A3; n=18) and composite resin (CR) (Z350-3M ESPE; n=18). Each group was subdivided into three subgroups and activated by a quartz-tungsten-halogen (QTH) lamp, an AL, or a light-emitting diode (LED) (n=6). Knoop microhardness (KHN) analysis of the materials was evaluated at two different depths: 0 and 1.6 mm from the enamel surface. The blocks were thermocycled and submitted to five demineralization–remineralization cycles at 37°C. The KHN values of the enamel surface (0 mm) were evaluated. The specimens were longitudinally sectioned, and the restorative material was evaluated at a depth of 1.6 mm. Data were evaluated by two way analysis of variance (ANOVA) and Tukey tests (p<0.05). The evaluation of subsuperficial enamel demineralization by KHN analysis was conducted by seven indentations located at 100 μm from the restored cavity. Data were evaluated by three way ANOVA and Tukey tests (p<0.05). Results: Comparing the two restorative materials, the KHN values at the surface (0 mm) were greater for CR, whereas at 1.6 mm, they were greater for RMGI. In addition, there was less development of enamel demineralization around RMGI restorations than CR restorations. Moreover, there were statistically significant differences on subsuperficial enamel demineralization between the two restorative materials and between the three photoactivation methods (p<0.05); RMGI presented the highest KHN values, and QTH and AL presented the

  2. Effect of postoperative peroxide bleaching on the marginal seal of composite restorations bonded with self-etch adhesives.

    PubMed

    Roubickova, A; Dudek, M; Comba, L; Housova, D; Bradna, P

    2013-01-01

    The aim of this study was to determine the effect of peroxide bleaching on the marginal seal of composite restorations bonded with several adhesive systems. Combined cylindrical Class V cavities located half in enamel and half in dentin were prepared on the buccal and lingual surfaces of human molars. The cavities were bonded with the self-etch adhesives Clearfil SE-Bond (CLF), Adper Prompt (ADP), and iBond (IBO) and an etch-and-rinse adhesive Gluma Comfort Bond (GLU) and restored with a microhybrid composite Charisma. Experimental groups were treated 25 times for eight hours per day with a peroxide bleaching gel Opalescence PF 20, while the control groups were stored in distilled water for two months and then subjected to a microleakage test using a dye penetration method. Scanning electron microscopy was used to investigate the etching and penetration abilities of the adhesives and morphology of debonded restoration-enamel interfaces after the microleakage tests. Statistical analyses were performed using nonparametric Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests at p=0.05. The microleakage of all GLU groups was low and not significantly affected by peroxide bleaching. Low microleakage was recorded for CLF control groups, but after bleaching, a small but significant increase in microleakage at the enamel margin indicated its sensitivity to peroxide bleaching. For ADP and IBO control groups, the microleakage at the enamel margins was significantly higher than for GLU and CLF and exceeded that at the dentin margins. Bleaching did not induce any significant changes in the microleakage. Electron microscopy analysis indicated that in our experimental setup, decreased adhesion and mechanical resistance of the ADP- and IBO-enamel interfaces could be more important than the chemical degradation effects induced by the peroxide bleaching gel. PMID:23570299

  3. Cuspal Movement and Microleakage in Premolar Teeth Restored with Posterior Restorative Materials

    PubMed Central

    Garapati, Surendranath; Das, Maneesha; Mujeeb, Abdul; Dey, Subhra; Kiswe, Santosh Panditrao

    2014-01-01

    Background: With the increase in various resin-based composites with varying monomeric formulations and fi llers had led to a significant number of problems, and one of such is postoperative pain. Clinician is in a dilemma what to select and what not to. The latest nanocomposite is there for a short while that no individual research is available currently, hence, this study was undertaken. The aim of this present study was to assess the cuspal deflection at each stage of polymerization for the incremental restoration of standardized large (mesio occlusal distal [MOD]) cavities with three posterior restorative resins. And also to assess the cervical microleakage. Materials and Methods: 18 extracted upper premolar teeth were selected. Teeth were divided into three groups (A, B, and C), each group consisting six teeth, large (MOD) cavity preparation was done. Groups A, B, and C were restored with P60, Filtek supreme (3M, ESPE), and ormocer material (Admira:Voco). The lingual cusps of the extracted teeth were approximated to the receptor of a compactor - deflection measuring gauge, following each stage of polymerization using light emitting diode curing light a measurement of the cuspal deflection was recorded. The restored teeth were prepared for microleakage testing and were examined under stereomicroscope at ×25 for the extent of the cervical gingival microleakage. Results: The cuspal deflection was the greatest for Filtek P60 and least for filtek supreme - nanocomposite with ormocer ranked between the two. For the microleakage, none of the materials were identified as producing less gingival microleakage. Conclusion: The lesser cuspal deflection values with filtek supreme nanocomposite could be due to resin chemistry and also filler particle size. Hence, this nanocomposite could be the first choice of material for use in large esthetic restorations. PMID:25395793

  4. Adhesive Bonding of Polymeric Materials for Automotive Applications

    SciTech Connect

    Warren, C.D., Boeman, R.G., Paulauskas, F.L.

    1994-11-18

    In 1992, the Oak Ridge National Laboratory (ORNL) began a cooperative research program with the Automotive Composites Consortium (ACC) to develop technologies that would overcome obstacles to the adhesive bonding of current and future automotive materials. This effort is part of a larger Department of Energy (DOE) program to promote the use of lighter weight materials in automotive structures. By reducing the weight of current automobiles, greater fuel economy and reduced emissions can be achieved. The bonding of similar and dissimilar materials was identified as being of primary importance since this enabling technology gives designers the freedom to choose from an expanded menu of low-mass materials for structural component weight reduction. Early in the project`s conception, five key areas were identified as being of primary importance to the automotive industry.

  5. [Research on the aging of all-ceramics restoration materials].

    PubMed

    Zhang, Dongjiao; Chen, Xinmin

    2011-10-01

    All-ceramic crowns and bridges have been widely used for dental restorations owing to their excellent functionality, aesthetics and biocompatibility. However, the premature clinical failure of all-ceramic crowns and bridges may easily occur when they are subjected to the complex environment of oral cavity. In the oral environment, all-ceramic materials are prone to aging. Aging can lead all-ceramic materials to change color, to lower bending strength, and to reduce anti-fracture toughness. There are many factors affecting the aging of the all-ceramic materials, for example, the grain size, the type of stabilizer, the residual stress and the water environment. In order to analyze the aging behavior, to optimize the design of all-ceramic crowns and bridges, and to evaluate the reliability and durability, we review in this paper recent research progress of aging behavior for all-ceramics restoration materials. PMID:22097281

  6. Comparison of the flexural strength of six reinforced restorative materials.

    PubMed

    Cohen, B I; Volovich, Y; Musikant, B L; Deutsch, A S

    2001-01-01

    This study calculated the flexural strength for six reinforced restorative materials and demonstrated that flexural strength values can be determined simply by using physical parameters (diametral tensile strength and Young's modulus values) that are easily determined experimentally. A one-way ANOVA analysis demonstrated a statistically significant difference between the two reinforced glass ionomers and the four composite resin materials, with the composite resin being stronger than the glass ionomers. PMID:12017792

  7. Materials and methods for autonomous restoration of electrical conductivity

    SciTech Connect

    Blaiszik, Benjamin J; Odom, Susan A; Caruso, Mary M; Jackson, Aaron C; Baginska, Marta B; Ritchey, Joshua A; Finke, Aaron D; White, Scott R; Moore, Jeffrey S; Sottos, Nancy R; Braun, Paul V; Amine, Khalil

    2014-03-25

    An autonomic conductivity restoration system includes a solid conductor and a plurality of particles. The particles include a conductive fluid, a plurality of conductive microparticles, and/or a conductive material forming agent. The solid conductor has a first end, a second end, and a first conductivity between the first and second ends. When a crack forms between the first and second ends of the conductor, the contents of at least a portion of the particles are released into the crack. The cracked conductor and the released contents of the particles form a restored conductor having a second conductivity, which may be at least 90% of the first conductivity.

  8. Catechol-Functionalized Synthetic Polymer as a Dental Adhesive to Contaminated Dentin Surface for a Composite Restoration

    PubMed Central

    2015-01-01

    This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet dentin surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to dentin surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe3+ additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated dentin surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe–catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives. PMID:26176305

  9. Restoration of intracellular ATP production in banked red blood cells improves inducible ATP export and suppresses RBC-endothelial adhesion

    PubMed Central

    Kirby, Brett S.; Hanna, Gabi; Hendargo, Hansford C.

    2014-01-01

    Transfusion of banked red blood cells (RBCs) has been associated with poor cardiovascular outcomes. Storage-induced alterations in RBC glycolytic flux, attenuated ATP export, and microvascular adhesion of transfused RBCs in vivo could contribute, but the underlying mechanisms have not been tested. We tested the novel hypothesis that improving deoxygenation-induced metabolic flux and the associated intracellular ATP generation in stored RBCs (sRBCs) results in an increased extracellular ATP export and suppresses microvascular adhesion of RBCs to endothelium in vivo following transfusion. We show deficient intracellular ATP production and ATP export by human sRBCs during deoxygenation (impairments ∼42% and 49%, respectively). sRBC pretreatment with a solution containing glycolytic intermediate/purine/phosphate precursors (i.e., “PIPA”) restored deoxygenation-induced intracellular ATP production and promoted extracellular ATP export (improvement ∼120% and 50%, respectively). In a nude mouse model of transfusion, adhesion of human RBCs to the microvasculature in vivo was examined. Only 2% of fresh RBCs (fRBCs) transfused adhered to the vascular wall, compared with 16% of sRBCs transfused. PIPA pretreatment of sRBCs significantly reduced adhesion to just 5%. In hypoxia, adhesion of sRBCs transfused was significantly augmented (up to 21%), but not following transfusion of fRBCs or PIPA-treated sRBCs (3.5% or 6%). Enhancing the capacity for deoxygenation-induced glycolytic flux within sRBCs increases their ability to generate intracellular ATP, improves the inducible export of extracellular anti-adhesive ATP, and consequently suppresses adhesion of stored, transfused RBCs to the vascular wall in vivo. PMID:25305182

  10. Effect of light-curing unit and adhesive system on marginal adaptation of class v composite restorations.

    PubMed

    Maia-Casseli, Denise S; Faria-e-Silva, André L; Cavalcanti, Andréa N; Romani, Eliene A O N; Martins, Luis R M

    2012-01-01

    The aim of this study was to evaluate the effect of light-curing units (LED or halogen) on the marginal adaptation of composite restorations performed with etch-and-rinse and self-etching adhesive. Class V cavities were prepared on bovine teeth with the gingival margin on dentin and the incisal margin on enamel. The cavities were restored with a micro-hybrid resin composite using an etch-and-rinse (Single Bond 2--SB) or a self-etching adhesive (Clearfil SE Bond--CL). The light-activations were performed using halogen lamp (Optilux 501--QTH) or second-generation light-emitting diode (Radii-Cal--LED) (n = 10). After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed under scanning electronic microscopy with 500x of magnification. The greatest gap width at each margin was recorded. Data were submitted to Mann-Whitney and Wilcoxon tests (a = 0.05). SB and CL showed similar behavior of enamel margins when the light-activations were performed with QTH. The same was observed for dentin margins with LED. When the LED was used, higher gap measurements at enamel margins were observed with CL, while higher gap values in dentin were observed for SB within QTH. No significant difference between substrates was found when CL was used. However, SB had significantly higher gap measurements in dentin. The light-curing unit seems to affect the marginal adaptation of resin composite restorations. However this effect was dependent on the adhesive and the location of the margin. PMID:22928384

  11. Modifying Matrix Materials to Increase Wetting and Adhesion

    NASA Technical Reports Server (NTRS)

    Zhong, Katie

    2011-01-01

    In an alternative approach to increasing the degrees of wetting and adhesion between the fiber and matrix components of organic-fiber/polymer matrix composite materials, the matrix resins are modified. Heretofore, it has been common practice to modify the fibers rather than the matrices: The fibers are modified by chemical and/or physical surface treatments prior to combining the fibers with matrix resins - an approach that entails considerable expense and usually results in degradation (typically, weakening) of fibers. The alternative approach of modifying the matrix resins does not entail degradation of fibers, and affords opportunities for improving the mechanical properties of the fiber composites. The alternative approach is more cost-effective, not only because it eliminates expensive fiber-surface treatments but also because it does not entail changes in procedures for manufacturing conventional composite-material structures. The alternative approach is best described by citing an example of its application to a composite of ultra-high-molecular- weight polyethylene (UHMWPE) fibers in an epoxy matrix. The epoxy matrix was modified to a chemically reactive, polarized epoxy nano-matrix to increase the degrees of wetting and adhesion between the fibers and the matrix. The modification was effected by incorporating a small proportion (0.3 weight percent) of reactive graphitic nanofibers produced from functionalized nanofibers into the epoxy matrix resin prior to combining the resin with the UHMWPE fibers. The resulting increase in fiber/matrix adhesion manifested itself in several test results, notably including an increase of 25 percent in the maximum fiber pullout force and an increase of 60-65 percent in fiber pullout energy. In addition, it was conjectured that the functionalized nanofibers became involved in the cross linking reaction of the epoxy resin, with resultant enhancement of the mechanical properties and lower viscosity of the matrix.

  12. Gradual surface degradation of restorative materials by acidic agents.

    PubMed

    Hengtrakool, Chanothai; Kukiattrakoon, Boonlert; Kedjarune-Leggat, Ureporn

    2011-01-01

    The aim of this study was to investigate the effect of acidic agents on surface roughness and characteristics of four restorative materials. Fifty-two discs were created from each restorative material: metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250), and amalgam (Valiant-PhD); each disc was 12 mm in diameter and 2.5 mm thick. The specimens were divided into four subgroups (n=13) and immersed for 168 hours in four storage media: deionized water (control); citrate buffer solution; green mango juice; and pineapple juice. Surface roughness measurements were performed with a profilometer, both before and after storage media immersion. Surface characteristics were examined using scanning electron microscopy (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey's tests. Ketac-S demonstrated the highest roughness changes after immersion in acidic agents (p<0.05), followed by Fuji II LC. Valiant-PhD and Filtek Z250 illustrated some minor changes over 168 hours. The mango juice produced the greatest degradation effect of all materials tested (p<0.05). SEM photographs demonstrated gradual surface changes of all materials tested after immersions. Of the materials evaluated, amalgam and resin composite may be the most suitable for restorations for patients with tooth surface loss. PMID:21903509

  13. Bonding of restorative materials to dentine: the present status in Japan.

    PubMed

    Nakabayashi, N

    1985-06-01

    Monomers which promote adhesion not only to enamel but also to dentine have been prepared. They have both hydrophilic and hydrophobic groups. The monomers are 2-hydroxy-3-beta-naphthoxypropyl methacrylate, 2-methacryloxyethyl phenyl hydrogen phosphoric acid and 4-methacryloxyethyl trimellitate anhydride. Chemical reaction between monomers and tooth substrates did not lead to adhesion. Cleaning of the ground tooth surface to remove the smeared layer with aqueous 10 per cent citric acid and 3 per cent ferric chloride solution prior to adhesion is recommended. Then, the lipophilic monomers will promote the inter-penetration of monomers into the hard tissues. The infiltrated methacrylates polymerize there and good adhesion takes place. The layer has good resistance against acid and is, in effect, a resin reinforced dentine and enamel as demonstrated by SEM and TEM. The tensile adhesive strength to the cleaned dentine was 18 MN/m2 and to the enamel 14 MN/m2. On the other hand, the value was reduced to 6 MN/m2 when the dentine had been etched by phosphoric acid or citric acid. The ferric chloride added to the citric acid protected dentinal collagen during demineralization. However, the ferric chloride provided ineffective protection against an acid as strong as phosphoric acid. The high bond strength was not dependent upon interlocking at the dentinal tubules as had been considered previously. The resin reinforced dentine and enamel is a hybrid of natural tissue and artificial material and is valuable in the prevention of secondary caries after restoration. PMID:3894241

  14. Overview: Damage resistance of graded ceramic restorative materials

    PubMed Central

    Zhang, Yu

    2012-01-01

    Improving mechanical response of materials is of great interest in a wide range of disciplines, including biomechanics, tribology, geology, optoelectronics, and nanotechnology. It has been long recognized that spatial gradients in surface composition and structure can improve the mechanical integrity of a material. This review surveys recent results of sliding-contact, flexural, and fatigue tests on graded ceramic materials from our laboratories and elsewhere. Although our findings are examined in the context of possible applications for next-generation, graded all-ceramic dental restorations, implications of our studies have broad impact on biomedical, civil, structural, and an array of other engineering applications. PMID:22778494

  15. Recent Advances in Materials for All-Ceramic Restorations

    PubMed Central

    Griggs, Jason A.

    2010-01-01

    SYNOPSIS The past three years of research on materials for all-ceramic veneers, inlays, onlays, single-unit crowns, and multi-unit restorations are reviewed. The primary changes in the field were the proliferation of zirconia-based frameworks and computer-aided fabrication of prostheses, as well as, a trend toward more clinically relevant in vitro test methods. This report includes an overview of ceramic fabrication methods, suggestions for critical assessment of material property data, and a summary of clinical longevity for prostheses constructed of various materials. PMID:17586152

  16. Effect of disinfection of custom tray materials on adhesive properties of several impression material systems.

    PubMed

    Thompson, G A; Vermilyea, S G; Agar, J R

    1994-12-01

    The effects of impression tray disinfection procedures on the bond strength of impression-material adhesives to two types of resin trays were evaluated with a tensile test. Autopolymerizing acrylic resin and a visible light-curing resin were formed into one-half inch cubes. A screw eye was attached to each cube before polymerization. Perforated trays were fabricated with stops to maintain an even one-eighth inch of impression material over the resin block. Hooks on the opposite side permitted attachment of the metal plate to a mechanical testing machine. Before adhesive was applied, one third of the resin specimens were immersed in a 1:213 iodophor solution; one third in a 10% sodium hypochlorite solution, and one third were kept in the "as fabricated" condition. Polysulfide, polyether, and polyvinyl siloxane impression material-adhesive systems were evaluated. The resin-impression material-metal plate couples were attached to a mechanical testing machine and tensile forces were applied at a separation rate of 5 inches per minute. Mean values for adhesive strength ranged from 3.49 kg/cm2 for the autopolymerizing acrylic resin/iodophor/polyether combination to 10.55 kg/cm2 for the autopolymerizing acrylic resin/untreated/polyvinyl siloxane combination. Differences were detected among materials and disinfecting procedure. Clinically, disinfection of resin trays may adversely affect retention of the impression material to the tray. PMID:7853264

  17. Fluoride and aluminum release from restorative materials using ion chromatography

    PubMed Central

    OKTE, Zeynep; BAYRAK, Sule; FIDANCI, Ulvi Reha; SEL, Tevhide

    2012-01-01

    Objective The aim of this study was to determine the amounts of fluoride and aluminum released from different restorative materials stored in artificial saliva and double-distilled water. Material and Methods Cylindrical specimens (10 x 1 mm) were prepared from 4 different restorative materials (Kavitan Plus, Vitremer, Dyract Extra, and Surefil). For each material, 20 specimens were prepared, 10 of which were stored in 5 mL artificial saliva and 10 of which were stored in 5 mL of double-distilled water. Concentrations of fluoride and aluminum in the solutions were measured using ion chromatography. Measurements were taken daily for one week and then weekly for two additional weeks. Data were analyzed using two-way ANOVA and Duncan's multiple range tests (p<0.05). Results The highest amounts of both fluoride and aluminum were released by the resin-modified glass ionomer cement Vitremer in double-distilled water (p<0.05). All materials released significantly more fluoride in double-distilled water than in artificial saliva (p<0.05). In artificial saliva, none of the materials were observed to release aluminum. Conclusion It was concluded that storage media and method of analysis should be taken into account when the fluoride and aluminum release from dental materials is assessed. PMID:22437674

  18. Finite element analysis of stress concentration in Class V restorations of four groups of restorative materials in mandibular premolar

    PubMed Central

    N, Shubhashini; N, Meena; Shetty, Ashish; Kumari, Anitha; DN, Naveen

    2008-01-01

    Aim: To study the concentration of stress in class V restoration of four different restorative materials subjected to occlusal load of 100N, 150N, 200N, 250N and to analyse the obtained data with the listed properties of the restorative material. Materials and Methods: Using FEM analysis the stresses generated in a class V lesion in a mandibular premolar was studied. Results: Within the framework of the aforementioned views, and from the results of the study it can be concluded that microfilled composite is the most suitable restorative material followed by flowable composite, glass ionomer cement and resin modified glass ionomer cement. Conclusion: Restoration of Class V lesions with materials of higher modulus of elasticity will enable better stress distribution. PMID:20142899

  19. The present and future of biologically inspired adhesive interfaces and materials.

    PubMed

    Brubaker, Carrie E; Messersmith, Phillip B

    2012-01-31

    The natural world provides many examples of robust, permanent adhesive platforms. Synthetic adhesive interfaces and materials inspired by mussels of genus Mytulis have been extensively applied, and it is expected that characterization and adaptation of several other biological adhesive strategies will follow the Mytilus edulis model. These candidate species will be introduced, along with a discussion of the adhesive behaviors that make them attractive for synthetic adaptation. While significant progress has been made in the development of biologically inspired adhesive interfaces and materials, persistent questions, current challenges, and emergent areas of research will be also be discussed. PMID:22224862

  20. Finite element stress analysis of short-post core and over restorations prepared with different restorative materials.

    PubMed

    Gurbuz, Taskin; Sengul, Fatih; Altun, Ceyhan

    2008-07-01

    The present study was conducted to determine the effect on the distribution of stress with the use of short-post cores and over restorations composed of different materials. The restorative materials used were namely two different composite resin materials (Valux Plus and Tetric Flow), a polyacid-modified resin material (Dyract AP), and a woven polyethylene fiber combination (Ribbond Fiber + Bonding agent + Tetric Flow). Finite element analysis (FEA) was used to develop a model for the maxillary primary anterior teeth. A masticatory force of 100 N was applied at 148 degrees to the incisal edge of the palatal surface of the crown model. Stress distributions and stress values were compared using von Mises criteria. The tooth model was assumed to be isotropic, homogeneous, elastic, and asymmetrical. It was observed that the highest stress usually occurred in the cervical area of the tooth when Tetric Flow was used as the short-post core and over restoration material. The same maximum stress value was also obtained when Ribbond fiber + Tetric Flow material was used for the short-post core. The results of FEA showed that the mechanical properties and elastic modulus of the restorative material influenced the stresses generated in enamel, dentin, and restoration when short-post core restorations were loaded incisally. Resin-based restorative materials with higher elastic moduli were found to be unsuitable as short-post core materials in endodontically treated maxillary primary anterior teeth. PMID:18833762

  1. Evaluation of hardness and wear resistance of interim restorative materials

    PubMed Central

    Savabi, Omid; Nejatidanesh, Farahnaz; Fathi, Mohamad Hossein; Navabi, Amir Arsalan; Savabi, Ghazal

    2013-01-01

    Background: The interim restorative materials should have certain mechanical properties to withstand in oral cavity. The aim of this study was to evaluate the hardness and wear resistance of interim restorative materials. Materials and Methods: Fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (TempSpan, Protemp 3 Garant, Revotek, Unifast LC, Tempron, Duralay, and Acropars). The Vickers hardness and abrasive wear of specimens were tested in dry conditions and after 1 week storage in artificial saliva. The depth of wear was measured using surface roughness inspection device. Data were subjected to Kruskal–Wallis and Mann–Whitney tests. The Pearson correlation coefficient was used to determine the relationship between hardness and wear (α =0.05). Results: TempSpan had the highest hardness. The wear resistance of TempSpan (in dry condition) and Revotek (after conditioning in artificial saliva) was significantly higher (P < 0.05). There was no statistically significant correlation between degree of wear and hardness of the materials (P = 0.281, r = −0.31). Conclusion: Hardness and wear resistance of interim resins are material related rather than category specified. PMID:23946734

  2. Generation and Evaluation of Lunar Dust Adhesion Mitigating Materials

    NASA Technical Reports Server (NTRS)

    Wohl, Christopher J.; Connell, John W.; Lin, Yi; Belcher, Marcus A.; Palmieri, Frank L.

    2011-01-01

    Particulate contamination is of concern in a variety of environments. This issue is especially important in confined spaces with highly controlled atmospheres such as space exploration vehicles involved in extraterrestrial surface missions. Lunar dust was a significant challenge for the Apollo astronauts and will be of greater concern for longer duration, future missions. Passive mitigation strategies, those not requiring external energy, may decrease some of these concerns, and have been investigated in this work. A myriad of approaches to modify the surface chemistry and topography of a variety of substrates was investigated. These involved generation of novel materials, photolithographic techniques, and other template approaches. Additionally, single particle and multiple particle methods to quantitatively evaluate the particle-substrate adhesion interactions were developed.

  3. Penetration of the pulp chamber by bleaching agents in teeth restored with various restorative materials.

    PubMed

    Gökay, O; Yilmaz, F; Akin, S; Tunçbìlek, M; Ertan, R

    2000-02-01

    It is thought that externally applied bleaching agents may penetrate into the pulp chamber. This study was conducted to evaluate the diffusion of peroxide bleaching agents into the pulp chamber of teeth restored with various restorative materials. Sixty-five human extracted anterior maxillary teeth were separated into the 13 groups containing 5 teeth. Five teeth (control group) were not subjected to any cavity preparation and restoration. Standardized class V cavities were prepared in the other 60 teeth and restored using composite resin (Charisma), polyacid modified composite resin (Dyract), or resin-modified glass ionomer cement (Vitremer). All teeth were sectioned 3 mm apical to the cementoenamel junction to remove the intracoronal pulp tissue, and the pulp chamber was filled with acetate buffer to absorb and stabilize any peroxide that might penetrate. Vestibular crown surfaces of teeth in the experimental groups were subjected to four different bleaching agents for 30 min at 37 degrees C, whereas the teeth in the control groups were exposed only to distilled water. Then the acetate buffer solution in the pulp chamber of each tooth was removed, and the pulp chamber of each tooth was rinsed with 100 ml of distilled water twice. Leukocrystal violet and enzyme horseradish peroxidase were added to the mixture of the acetate buffer and rinse water. The optical density of the resulting blue solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. Higher hydrogen peroxide concentrations resulted in a higher pulpal peroxide penetration. The highest pulpal peroxide penetration was found in resin-modified glass ionomer cement groups, whereas composite resin groups showed the lowest pulpal peroxide penetration. PMID:11194380

  4. [Adhesion of dental silicone rubber material to thermoplastic material for mouthguards].

    PubMed

    Yokota, Kayoko

    2010-03-01

    A preliminary study revealed that an autopolymerization addition silicone resilient denture relining material (SI) had excellent shock absorption properties similar to those of thermoplastic materials commonly used for mouthguards (ethylene-vinyl acetate: EVA). The aim of the present study was to examine the bonding strength of SI and EVA using a newly-developed adhesive prototype. Delamination tests and tensile strength tests were performed to compare the bonding strengths of SI on EVA prepared under the following four conditions: 1) Control condition (no preparation; C), 2) Sandblasting (S), 3) Bonding with the adhesive prototype (M), and 4) Combination of sandblasting preparation and bonding with the adhesive prototype (SM). The mean bonding strength (S. D.) of the delamination tests under the C, S, M and SM conditions were 0.167 (0.003) N/mm, 0.273 (0.034) N/mm, 0.242 (0.027) N/mm and 0.506 (0.113) N/mm, respectively. The mean bonding strength (S. D.) of the tensile strength tests under the C, S, M and SM conditions were 0.006 (0.011) MPa, 0.081 (0.105) MPa, 0.231 (0.069) MPa and 0.590 (0.041) MPa, respectively. Two-way analysis of variances and Tukey's HSD test detected that the combination of sandblasting preparation and bonding with the adhesive prototype significantly improved the bonding strength between SI and EVA. The results indicate that the self-curing addition silicone resilient denture relining material may adhere to the thermoplastic material prepared by combined application of sandblasting and the adhesive prototype, suggesting the potential of the dental silicone rubber material as a material for repairing mouthguards in clinical practice. PMID:20415249

  5. Biodegradation and abrasive wear of nano restorative materials.

    PubMed

    de Paula, A B; Fucio, S B P; Ambrosano, G M B; Alonso, R C B; Sardi, J C O; Puppin-Rontani, R M

    2011-01-01

    The purpose of this study was to evaluate the biomechanical degradation of two nanofilled restorative materials (a resin-modified glass ionomer, Ketac N100 and a composite, Filtek Z350), compared with conventional materials (Vitremer and TPH Spectrum). Twenty specimens obtained from each material were divided into two storage groups (n=10): relative humidity (control) and Streptococcus mutans biofilm (biodegradation). After 7 days of storage, roughness values (Ra) and micrographs by scanning electron microscopy (SEM) were obtained. In a second experimental phase, the specimens previously subjected to biodegradation were fixed to the tooth-brushing device and abraded via toothbrushes, using dentifrice slurry (mechanical degradation). Next, these specimens were washed, dried, and reassessed by roughness and SEM. The data were submitted to repeated measures three-way analysis of variance (ANOVA) and Tukey tests (p<0.05). There was statistically significant interaction among factors: material, storage (humidity/biofilm), and abrasion (before/after). After biodegradation (S mutans biofilm storage), Ketac N100 presented the highest Ra values. Concerning bio plus mechanical challenge, TPH Spectrum, Ketac N100, and Vitremer presented the undesirable roughening of their surfaces, while the nano composite Filtek Z350 exhibited the best resistance to cumulative challenges proposed. The degraded aspect after biodegradation and the exposure of fillers after mechanical degradation were visualized in micrographs. This study demonstrated that the nanotechnology incorporated in restorative materials, as in composite resin and resin-modified glass ionomer, was important for the superior resistance to biomechanical degradation. PMID:21913859

  6. Amyloid-β (1-40) restores adhesion properties of pulmonary surfactant, counteracting the effect of cholesterol.

    PubMed

    Hane, F T; Drolle, E; Leonenko, Z

    2014-08-01

    A pulmonary surfactant (PS) is a thin lipid-protein film covering the surface of the lung alveoli at the air/liquid interface. The primary purpose of a PS is to control the surface tension of the air/liquid interface and to reduce the work of breathing. High levels of cholesterol in a PS are associated with life-threatening acute respiratory distress syndrome (ARDS) and acute lung injury (ALI). Finding therapeutics to counteract the effect of cholesterol in a PS is a matter of contemporary research. In our earlier work, we showed that the addition of amyloid-β (1-40) (Aβ40), the protein implicated in Alzheimer's disease, can reverse the detrimental effects of cholesterol in surfactants by improving multilayer formation and restoring PS surface active properties. We hypothesized that this phenomenon was due to Aβ40 improving adhesion properties of a surfactant. In this work we used atomic force spectroscopy to demonstrate that Aβ40 counteracts the adhesive properties of a PS compromised by high levels of cholesterol in a PS and helps to restore the functionality of a PS. PMID:24947303

  7. Adhesive materials and processing selection for environmentally conscious manufacturing

    SciTech Connect

    Tira, J.S.

    1995-06-01

    Manufacturers that use certain adhesives and related manufacturing processes must consider the impact they have on worker health, safety, and the environment. Product manufacturers must find alternate replacements for solvent-based adhesives and solvent cements. In addition, processes that use ozone-depleting solvents for hand-wipe cleaning operations as well as vapor degreasing must find suitable alternates in order to be environmentally compliant. Likewise, manufacturers that use etching solutions that contain chrome must find a replacement. This paper identifies some of the specific problems associated with using certain adhesives and manufacturing processes. Environmentally acceptable alternative adhesives and processes are presented.

  8. Backscattering from dental restorations and splint materials during therapeutic radiation

    SciTech Connect

    Farman, A.G.; Sharma, S.; George, D.I.; Wilson, D.; Dodd, D.; Figa, R.; Haskell, B.

    1985-08-01

    Models were constructed to simulate as closely as possible the human oral cavity. Radiation absorbed doses were determined for controls and various test situations involving the presence of dental restorative and splint materials during cobalt-60 irradiation of the models. Adjacent gold full crowns and adjacent solid dental silver amalgam cores both increased the dose to the interproximal gingivae by 20%. Use of orthodontic full bands for splinting the jaws increased the dose to the buccal tissues by an average of 10%. Augmentation of dose through backscatter radiation was determined to be only slight for intracoronal amalgam fillings and stainless steel or plastic bracket splints.

  9. 49 CFR 173.173 - Paint, paint-related material, adhesives, ink and resins.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Paint, paint-related material, adhesives, ink and... Than Class 1 and Class 7 § 173.173 Paint, paint-related material, adhesives, ink and resins. (a) When... requirements apply. Except as otherwise provided in this part, the description “Paint” is the proper...

  10. 49 CFR 173.173 - Paint, paint-related material, adhesives, ink and resins.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Paint, paint-related material, adhesives, ink and... Than Class 1 and Class 7 § 173.173 Paint, paint-related material, adhesives, ink and resins. (a) When... requirements apply. Except as otherwise provided in this part, the description “Paint” is the proper...

  11. 49 CFR 173.173 - Paint, paint-related material, adhesives, ink and resins.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Paint, paint-related material, adhesives, ink and... Than Class 1 and Class 7 § 173.173 Paint, paint-related material, adhesives, ink and resins. (a) When... requirements apply. Except as otherwise provided in this part, the description “Paint” is the proper...

  12. Effect of thermal shock loadings on stability of dentin-composite polymer material adhesive interfaces

    NASA Astrophysics Data System (ADS)

    Bessudnova, Nadezda O.; Shlyapnikova, Olga A.; Venig, Sergey B.; Gribov, Andrey N.

    2015-03-01

    In the past several decades the problem of longevity and durability of adhesive interfaces between hard tooth tissues and composite resin-based materials are of great interest among dental researchers and clinicians. These parameters are partially determined by adhesive system mechanical properties. In the present research project nanoindentation has been examined to test hardness of dental adhesive systems. A series of laboratory experiments was performed to study the effect of light curing time and oxygen inhibition phenomenon on light-cured adhesive material hardness. An adhesive system AdperTM Single Bond (3M ESPE) was selected as a material for testing. The analysis of experimental data revealed that the maximum values of hardness were observed after the material had been light-cured for 20 seconds, as outlined in guidelines for polymerization time of the adhesive system. The experimental studies of oxygen inhibition influence on adhesive system hardness pointed out to the fact that the dispersive layer removal led to increase in adhesive system hardness. A long - time exposure of polymerized material of adhesive system at open air at room temperature resulted in no changes in its hardness, which was likely to be determined by the mutual effect of rival processes of air oxygen inhibition and directed light curing.

  13. Oxalic acid under adhesive restorations as a means to reduce dentin sensitivity: a four-month clinical trial.

    PubMed

    Barrientos, Claudia; Xaus, Gloria; Leighton, Catherine; Martin, Javier; Gordan, Valeria V; Moncada, Gustavo

    2011-01-01

    The aim of this double-blind randomized controlled clinical trial was to evaluate the reduction of dentin sensitivity using an oxalate-based compound, placed under adhesive restorations, during a four-month period. One hundred three preoperatively sensitive teeth, on 36 patients aged 25-66 years (mean, 40.3±7), were included in the study. Group A (experimental) was treated with oxalic acid (BisBlock) before resin-based composite (RBC) restorations (n=52), and group B (control) was treated with distilled water before RBC restorations (n=51). The first tooth in each patient was randomly assigned to group A, and the second tooth received group B. Clinical evaluation as made by a thermal/evaporation test with an air syringe and measurement by visual analog scale (VAS) at baseline and four months after treatment. The results showed sensitivity reduction during the evaluation period (expressed in VAS values): group A, 7.6 to 0.8; group B, 7.3 to 2.6. We concluded from this study that both treatments reduced dentin sensitivity during the evaluation period, with group A showing significantly less dentin sensitivity after four months (p<0.05). PMID:21777095

  14. Material characterization of structural adhesives in the lap shear mode

    NASA Technical Reports Server (NTRS)

    Sancaktar, E.; Schenck, S. C.

    1983-01-01

    A general method for characterizing structual adhesives in the bonded lap shear mode is proposed. Two approaches in the form of semiempirical and theoretical approaches are used. The semiempirical approach includes Ludwik's and Zhurkov's equations to describe respectively, the failure stresses in the constant strain rate and constant stress loading modes with the inclusion of the temperature effects. The theoretical approach is used to describe adhesive shear stress-strain behavior with the use of viscoelastic or nonlinear elastic constitutive equations. Two different model adhesives are used in the single lap shear mode with titanium adherends. These adhesives (one of which was developed at NASA Langley Research Center) are currently considered by NASA for possible aerospace applications. Use of different model adhesives helps in assessment of the generality of the method.

  15. Criteria for clinical translucency evaluation of direct esthetic restorative materials.

    PubMed

    Lee, Yong-Keun

    2016-08-01

    The purpose of this review was to suggest practical criteria for the clinical translucency evaluation of direct esthetic restorative materials, and to review the translucency with these criteria. For the evaluation of reported translucency values, measuring instrument and method, specimen thickness, background color, and illumination should be scrutinized. Translucency parameter (TP) of 15 to 19 could be regarded as the translucency of 1 mm thick human enamel. Visual perceptibility threshold for translucency difference in contrast ratio (ΔCR) of 0.07 could be transformed into ΔTP value of 2. Translucency differences between direct and indirect resin composites were perceivable (ΔTP > 2). Universal and corresponding flowable resin composites did not show perceivable translucency differences in most products. Translucency differed significantly by the product within each shade group, and by the shade group within each product. Translucency of human enamel and perceptibility threshold for translucency difference may be used as criteria for the clinical evaluation of translucency of esthetic restorative materials. PMID:27508156

  16. Criteria for clinical translucency evaluation of direct esthetic restorative materials

    PubMed Central

    2016-01-01

    The purpose of this review was to suggest practical criteria for the clinical translucency evaluation of direct esthetic restorative materials, and to review the translucency with these criteria. For the evaluation of reported translucency values, measuring instrument and method, specimen thickness, background color, and illumination should be scrutinized. Translucency parameter (TP) of 15 to 19 could be regarded as the translucency of 1 mm thick human enamel. Visual perceptibility threshold for translucency difference in contrast ratio (ΔCR) of 0.07 could be transformed into ΔTP value of 2. Translucency differences between direct and indirect resin composites were perceivable (ΔTP > 2). Universal and corresponding flowable resin composites did not show perceivable translucency differences in most products. Translucency differed significantly by the product within each shade group, and by the shade group within each product. Translucency of human enamel and perceptibility threshold for translucency difference may be used as criteria for the clinical evaluation of translucency of esthetic restorative materials. PMID:27508156

  17. Colour measurements of surfaces to evaluate the restoration materials

    NASA Astrophysics Data System (ADS)

    Lo Monaco, Angela; Marabelli, Maurizio; Pelosi, Claudia; Picchio, Rodolfo

    2011-06-01

    In this paper two case studies on the application of colour measurements for the evaluation of some restoration materials are discussed. The materials related to the research are: watercolours employed in restoration of wall paintings and preservative/consolidants for wood artifacts. Commercial watercolours, supplied by Maimeri, Windsor&Newton and Talens factories have been tested. Colour measurements have been performed by means of a reflectance spectrophotometer (RS) before and after accelerated ageing of watercolours at 92% relative humidity (RH) and in a Solar Box chamber. The experimental results show that watercolours based on natural earths and artificial ultramarine undergo the main colour changes, expressed as L*, a* and b* variations and total colour difference (▵E*). In the other cases colour differences depend on both watercolour typology and suppliers. The other example concerns the evaluation of colour change due to surface treatment of Poplar (Populus sp.) and chestnut (Castanea sativa L.) wood samples. The wooden samples have been treated with a novel organic preservative/consolidant product that has been tested also in a real case as comparison. The treated samples have been artificially aged in Solar Box chamber equipped with a 280 nm UV filter. Colour has been measured before and after the artificial ageing by means of a RS. Colour changes have been determined also for the main door of an historical mansion in Viterbo, made of chestnut wood, and exposed outdoors.

  18. Effect of aluminum chloride hemostatic agent on microleakage of class V composite resin restorations bonded with all-in-one adhesive

    PubMed Central

    Mohammadi, Narmin; Bahari, Mahmood; Pournaghi-Azar, Fatemeh; Mozafari, Aysan

    2012-01-01

    Objectives: Since hemostatic agents can induce changes on enamel and dentin surfaces and influence composite resin adhesion, the aim of the present study was to evaluate the effect of the aluminum chloride hemostatic agent on the gingival margin microleakage of class V (Cl V) composite resin restorations bonded with all-in-one adhesive. Study design: Cl V cavities were prepared on the buccal surfaces of 60 sound bovine permanent incisors. Gingival margins of the cavities were placed 1.5 mm apical to the cemento-enamel junction (CEJ). The teeth were randomly divided into two groups of 30. In group 1, the cavities were restored without the application of a hemostatic agent; in group 2, the cavities were restored after the application of the hemostatic agent. In both groups all-in-one adhesive and Z250 composite resin were used to restore the cavities with the incremental technique. After finishing and polishing, the samples underwent a thermocycling procedure, followed by immersion in 2% basic fuschin solution for 24 hours. The samples were sectioned and gingival microleakage was evaluated under a stereomicroscope. The non-parametric Mann-Whitney U test was used to compare microleakage between the two groups. Statistical significance was defined at P<0.05. Results: A statistically significant difference was observed in microleakage between the two groups (P<0.001). Conclusions: Contamination of Cl V composite resin restorations bonded with all-in-one adhesive with aluminum chloride hemostatic agent significantly increases restoration gingival margin microleakage. Key words:All-in-one adhesive resin, composite resin restoration, hemostatic agent, microleakage. PMID:22322497

  19. Appropriate use of genetic manipulation for the development of restoration plant materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diversity of restoration plant material development approaches reflect a variety of philosophies that represent what should and can be accomplished by restoration. The "natural" approach emphasizes emulation of putative naturally occurring patterns of genetic variation. The "genetically manipu...

  20. Changes in materials properties explain the effects of humidity on gecko adhesion.

    PubMed

    Puthoff, Jonathan B; Prowse, Michael S; Wilkinson, Matt; Autumn, Kellar

    2010-11-01

    Geckos owe their remarkable stickiness to millions of dry setae on their toes, and the mechanism of adhesion in gecko setae has been the topic of scientific scrutiny for over two centuries. Previously, we demonstrated that van der Waals forces are sufficient for strong adhesion and friction in gecko setae, and that water-based capillary adhesion is not required. However, recent studies demonstrated that adhesion increases with relative humidity (RH) and proposed that surface hydration and capillary water bridge formation is important or even necessary. In this study, we confirmed a significant effect of RH on gecko adhesion, but rejected the capillary adhesion hypothesis. While contact forces of isolated tokay gecko setal arrays increased with humidity, the increase was similar on hydrophobic and hydrophilic surfaces, inconsistent with a capillary mechanism. Contact forces increased with RH even at high shear rates, where capillary bridge formation is too slow to affect adhesion. How then can a humidity-related increase in adhesion and friction be explained? The effect of RH on the mechanical properties of setal β-keratin has escaped consideration until now. We discovered that an increase in RH softens setae and increases viscoelastic damping, which increases adhesion. Changes in setal materials properties, not capillary forces, fully explain humidity-enhanced adhesion, and van der Waals forces remain the only empirically supported mechanism of adhesion in geckos. PMID:20952618

  1. In situ reaction kinetic analysis of dental restorative materials

    NASA Astrophysics Data System (ADS)

    Younas, Basma; Samad Khan, Abdul; Muzaffar, Danish; Hussain, Ijaz; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur

    2013-12-01

    The objective of this study was to evaluate in situ structural and thermal changes of dental restorative materials at periodical time intervals. The commercial materials included zinc oxide eugenol (ZOE), zinc phosphate type I (ZnPO4), glass ionomer cement type II (GIC) and resin-based nano-omposite (Filtek Z350 XT). These materials were processed according to manufacturer's instructions. For the structural analysis Fourier transform infrared spectroscopy (FTIR) was used at high resolution. TGA was used to evaluate thermal weight-loss. The FTIR spectra were collected at periodic time intervals. FTIR spectra showed that with time passing all materials exhibited an increase in peak intensities and a new appearance of shoulders and shifting of peaks for example, ZnPO4 (P-O), ZOE (C═O, C═N, C-O-C), GIC (COO-, C-H, Si-OH), composites (C═O, C═C, C═N, C-N-H). The peaks were replaced by bands and these bands became broader with time interval. Composites showed a degree of conversion and new peaks corresponded to the cross-linking of polymer composites. TGA analysis showed that significant changes in weight loss of set materials were observed after 24 h, where ZOE showed continuous changes in thermal degradation. The spectral changes and thermal degradation with time interval elucidated in situ setting behaviour and understanding of their bonding compatibility with tooth structure and change in relation to time.

  2. Esthetic rehabilitation with tooth bleaching, enamel microabrasion, and direct adhesive restorations.

    PubMed

    Bezerra-Júnior, Douglas Machado; Silva, Luciana Mendonça; Martins, Leandro de Moura; Cohen-Carneiro, Flávia; Pontes, Danielson Guedes

    2016-01-01

    The aim of this case report is to report esthetic rehabilitation with combined tooth bleaching, enamel microabrasion, and anterior restoration replacement in a 26-year-old man. Clinical examination showed deficient restorations in the maxillary anterior teeth, significant discoloration of the maxillary left central incisor, and hypoplastic stains affecting the maxillary right lateral incisor. A radiograph of the left central incisor showed satisfactory endodontic treatment, allowing preparation for the walking bleach technique. For 3 weeks, 37% carbamide peroxide in the pulp chamber was renewed every week. In-office bleaching with 35% hydrogen peroxide was also performed on the maxillary teeth. After 21 days, all teeth had been bleached to shade A1. After bleaching was completed, enamel microabrasion of the maxillary right lateral incisor was conducted with 6% hydrochloric acid. In later sessions, microhybrid composite resin restorations were placed in all 4 maxillary incisors. A combination of dental bleaching techniques, enamel microabrasion, and resin restorations was a successful and conservative choice for reestablishing the natural appearance of discolored teeth, improving the self-esteem of the patient. PMID:26943091

  3. Study of materials and adhesives for superconducting cable feedthroughs

    NASA Astrophysics Data System (ADS)

    Perin, A.; Jareño, R. Macias; Metral, L.

    2002-05-01

    Powering superconducting magnets requires the use of cryogenic feedthroughs for the superconducting cables capable of withstanding severe thermal, mechanical and electrical operating conditions. Such feedthroughs shall provide the continuity of the superconducting circuit while ensuring a hydraulic separation at cryogenic temperature. A study about the adhesive and polymers required for the production of thermal shock resistant feedthroughs is presented. The strength of the busbar to adhesive joints was first investigated by compression/shear tests as well as pin-and-collar tests performed with four epoxy adhesives. After the selection of the most appropriate adhesive, pin-and-collar tests were performed with four different polymers. Based on the results, a superconducting cable feedthrough for 6 busbars of 6 kA and 12 busbars of 120 A was constructed and successfully tested.

  4. Evaluation of adhesive materials used on the Long Duration Exposure Facility

    NASA Technical Reports Server (NTRS)

    Dursch, H. W.; Keough, B. K.; Pippin, H. G.

    1995-01-01

    The adhesive and adhesive-like materials flown on LDEF included epoxies and silicones (including lap shear specimens), conformal coatings, potting compounds, and several tapes and transfer films. With the exception of the lap shear specimens, these materials were used in the fabrication and assembly of the experiments such as bonding thermal control surfaces to other hardware and holding individual specimens in place, similar to applications on other spacecraft. Typically, the adhesives were not exposed to solar radiation or atomic oxygen. Only one adhesive system was used in a structural application. This report documents all results of the Materials and Systems SIG investigation into the effect of long term low Earth orbit (LEO) exposure of these materials. Results of this investigation show that if the material was shielded from exposure to LDEF's external environment, the 69 month exposure to LEO had, in most cases, minimal effect on the material.

  5. Evaluation of adhesive materials used on the Long Duration Exposure Facility. Report, October 1989-January 1995

    SciTech Connect

    Dursch, H.W.; Keough, B.K.; Pippin, H.G.

    1995-03-01

    The adhesive and adhesive-like materials flown on LDEF included epoxies and silicones (including lap shear specimens), conformal coatings, potting compounds, and several tapes and transfer films. With the exception of the lap shear specimens, these materials were used in the fabrication and assembly of the experiments such as bonding thermal control surfaces to other hardware and holding individual specimens in place, similar to applications on other spacecraft. Typically, the adhesives were not exposed to solar radiation or atomic oxygen. Only one adhesive system was used in a structural application. This report documents all results of the Materials and Systems SIG investigation into the effect of long term low Earth orbit (LEO) exposure of these materials. Results of this investigation show that if the material was shielded from exposure to LDEF`s external environment, the 69 month exposure to LEO had, in most cases, minimal effect on the material.

  6. Restoring E-cadherin-mediated cell-cell adhesion increases PTEN protein level and stability in human breast carcinoma cells

    SciTech Connect

    Li Zengxia; Wang Liying; Zhang Wen; Fu Yi; Zhao Hongbo; Hu Yali; Prins, Bram Peter; Zha Xiliang

    2007-11-09

    The phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a well-characterized tumor suppressor that negatively regulates cell growth and survival. Despite the critical role of PTEN in cell signaling, the mechanisms of its regulation are still under investigation. We reported here that PTEN expression could be controlled by overexpression or knock-down of E-cadherin in several mammary carcinoma cell lines. Furthermore, we showed that the accumulation of PTEN protein in E-cadherin overexpressing cells was due to increased PTEN protein stability rather than the regulation of its transcription. The proteasome-dependent PTEN degradation pathway was impaired after restoring E-cadherin expression. Moreover, maintenance of E-cadherin mediated cell-cell adhesion was necessary for its regulating PTEN. Altogether, our results suggested that E-cadherin mediated cell-cell adhesion was essential for preventing the proteasome degradation of PTEN, which might explain how breast carcinoma cells which lost cell-cell contact proliferate rapidly and are prone to metastasis.

  7. Effect of repeated contact on adhesion measurements involving polydimethylsiloxane structural material

    NASA Astrophysics Data System (ADS)

    Kroner, E.; Maboudian, R.; Arzt, E.

    2009-09-01

    During the last few years several research groups have focused on the fabrication of artificial gecko inspired adhesives. For mimicking these structures, different polymers are used as structure material, such as polydimethylsiloxanes (PDMS), polyurethanes (PU), and polypropylene (PP). While these polymers can be structured easily and used for artificial adhesion systems, the effects of repeated adhesion testing have never been investigated closely. In this paper we report on the effect of repeated adhesion measurements on the commercially available poly(dimethylsiloxane) polymer kit Sylgard 184 (Dow Corning). We show that the adhesion force decreases as a function of contact cycles. The rate of change and the final value of adhesion are found to depend on the details of the PDMS synthesis and structuring.

  8. Evaluation of nystatin containing chitosan hydrogels as potential dual action bio-active restorative materials: in vitro approach.

    PubMed

    Perchyonok, V Tamara; Reher, Vanessa; Zhang, Shengmiao; Basson, Nicki; Grobler, Sias

    2014-01-01

    Healing is a specific biological process related to the general phenomenon of growth and tissue regeneration and is a process generally affected by several systemic conditions or as detrimental side-effects of chemotherapy- and radiotherapy-induced inflammation of the oral mucosa. The objectives of this study is to evaluate the novel chitosan based functional drug delivery systems, which can be successfully incorporated into "dual action bioactive restorative materials", capable of inducing in vitro improved wound healing prototype and containing an antibiotic, such as nystatin, krill oil as an antioxidant and hydroxyapatite as a molecular bone scaffold, which is naturally present in bone and is reported to be successfully used in promoting bone integration when implanted as well as promoting healing. The hydrogels were prepared using a protocol as previously reported by us. The physico-chemical features, including surface morphology (SEM), release behaviors, stability of the therapeutic agent-antioxidant-chitosan, were measured and compared to the earlier reported chitosan-antioxidant containing hydrogels. Structural investigations of the reactive surface of the hydrogel are reported. Release of nystatin was investigated for all newly prepared hydrogels. Bio-adhesive studies were performed in order to assess the suitability of these designer materials. Free radical defense capacity of the biomaterials was evaluated using established in vitro model. The bio-adhesive capacity of the materials in the in vitro system was tested and quantified. It was found that the favorable synergistic effect of free radical built-in defense mechanism of the new functional materials increased sustainable bio-adhesion and therefore acted as a functional multi-dimensional restorative material with potential application in wound healing in vitro. PMID:25459982

  9. Interface adhesion between 2D materials and elastomers measured by buckle delamination

    NASA Astrophysics Data System (ADS)

    Brennan, Christopher; Lu, Nanshu

    2015-03-01

    A major application for 2D materials is creating electronic devices, including flexible and wearable devices. These applications require complicated fabrication processes where 2D materials are either mechanically exfoliated or grown via chemical vapor deposition and then transferred to a host substrate. Both processes require intimate knowledge of the interactions between the 2D material and the substrate to allow for a controllable transfer. Although adhesion between 2D materials and stiff substrates such as silicon and copper have been measured by bulge or peeling tests, adhesion between 2D materials and soft polymer substrates are hard to measure by conventional methods. Here we propose a simple way of measuring the adhesion between 2D materials and soft, stretchable elastomers using mature continuum mechanics equations. By creating buckle delamination in 2D atomic layers and measuring the buckle profile using an atomic force microscope, we can readily extract 2D-elastomer adhesion energy. Here we look at the adhesion of MoS2 and graphene to PDMS. The measured adhesion values are found insensitive to the applied strains in the substrate and are one order smaller than 2D-silicon oxide adhesion which is mainly attributed substrate surface roughness differences.

  10. Comparison of wear-resistance of Class V restorative materials.

    PubMed

    Frazier, K B; Rueggeberg, F A; Mettenburg, D J

    1998-01-01

    Compomers and resin-modified glass ionomers have been developed to improve the physical properties of traditional glass ionomer cements. This project compared the toothbrush wear-resistance of three compomers (Compoglass, Dyract, Hytac) and three resin-modified glass ionomer restorative materials (Fuji II LC, Photac-Fil, Vitremer) to that of two resin-based composites (Herculite XRV, Silux Plus). Specimens (n = 7) were prepared according to manufacturers' instructions and stored in a humidor for 48 hours prior to testing. The specimens were subjected to 120,000 strokes at 1.5 Hz, using a brush-head force of 200 g on a Manly V-8 cross-brushing machine. The slurry contained a 50:50 (w/w) mixture of toothpaste and deionized water. Abrasion-resistance was calculated by measuring specimen mass-loss prior to and subsequent to brushing. The data were analyzed using a one-way analysis of variance (ANOVA) and the Tukey-Kramer post-hoc test. Significant differences (p < .0001) in mass-loss were found, and loss ranged from 0.013 +/- 0.003 g (Hytac) to 0.061 +/- 0.009 g (Compoglass). No correlation (p = .959) between wear-resistance and experimentally determined filler content existed. This study showed that all but one hybrid resin-ionomer type material exhibited a resistance to toothbrush wear that was as good as or better than that of the two traditional resin-based composite materials. PMID:10321201

  11. Shear bond strength of bulk-fill and nano-restorative materials to dentin

    PubMed Central

    Colak, Hakan; Ercan, Ertugrul; Hamidi, Mehmet Mustafa

    2016-01-01

    Objectives: Bulk-fill composite materials are being developed for preparation depths of up to 4 mm in an effort to simplify and improve the placement of direct composite posterior restorations. The aim of our study was to compare shear-bond strength of bulk-fill and conventional posterior composite resins. Materials and Methods: In this study, 60 caries free extracted human molars were used and sectioned parallel to occlusal surface to expose midcoronal dentin. The specimens were randomly divided into four groups. Total-etch dentine bonding system (Adper Scotchbond 1XT, 3M ESPE) was applied to dentin surface in all the groups to reduce variability in results. Then, dentine surfaces covered by following materials. Group I: SonicFill Bulk-Fill, Group II: Tetric EvoCeram (TBF), Group III: Herculite XRV Ultra, and Group IV: TBF Bulk-Fill, 2 mm × 3 mm cylindrical restorations were prepared by using application apparatus. Shear bond testing was measured by using a universal testing machine. Kruskal–Wallis and Mann–Whitney U-tests were performed to evaluate the data. Results: The highest value was observed in Group III (14.42 ± 4.34) and the lowest value was observed in Group IV (11.16 ± 2.76) and there is a statistically significant difference between these groups (P = 0.046). However, there is no statistically significant difference between the values of other groups. In this study, Group III was showed higher strength values. Conclusion: There is a need for future studies about long-term bond strength and clinical success of these adhesive and bulk-fill systems. PMID:27011738

  12. Adhesion and interfacial fracture toughness between hard and soft materials

    NASA Astrophysics Data System (ADS)

    Rahbar, Nima; Wolf, Kurt; Orana, Argjenta; Fennimore, Roy; Zong, Zong; Meng, Juan; Papandreou, George; Maryanoff, Cynthia; Soboyejo, Wole

    2008-11-01

    This paper presents the results of a combined experimental and theoretical study of adhesion between hard and soft layers that are relevant to medical devices such as drug-eluting stents and semiconductor applications. Brazil disk specimens were used to measure the interfacial fracture energies between model parylene C and 316L stainless steel over a wide range of mode mixities. The trends in the overall fracture energies are predicted using a combination of adhesion theories and fracture mechanics concepts. The measured interfacial fracture energies are shown to be in good agreement with the predictions.

  13. Evaluation of Nystatin Containing Chitosan Hydrogels as Potential Dual Action Bio-Active Restorative Materials: in Vitro Approach

    PubMed Central

    Perchyonok, V. Tamara; Reher, Vanessa; Zhang, Shengmiao; Basson, Nicki; Grobler, Sias

    2014-01-01

    Healing is a specific biological process related to the general phenomenon of growth and tissue regeneration and is a process generally affected by several systemic conditions or as detrimental side-effects of chemotherapy- and radiotherapy-induced inflammation of the oral mucosa. The objectives of this study is to evaluate the novel chitosan based functional drug delivery systems, which can be successfully incorporated into “dual action bioactive restorative materials”, capable of inducing in vitro improved wound healing prototype and containing an antibiotic, such as nystatin, krill oil as an antioxidant and hydroxyapatite as a molecular bone scaffold, which is naturally present in bone and is reported to be successfully used in promoting bone integration when implanted as well as promoting healing. The hydrogels were prepared using a protocol as previously reported by us. The physico-chemical features, including surface morphology (SEM), release behaviors, stability of the therapeutic agent-antioxidant-chitosan, were measured and compared to the earlier reported chitosan-antioxidant containing hydrogels. Structural investigations of the reactive surface of the hydrogel are reported. Release of nystatin was investigated for all newly prepared hydrogels. Bio-adhesive studies were performed in order to assess the suitability of these designer materials. Free radical defense capacity of the biomaterials was evaluated using established in vitro model. The bio-adhesive capacity of the materials in the in vitro system was tested and quantified. It was found that the favorable synergistic effect of free radical built-in defense mechanism of the new functional materials increased sustainable bio-adhesion and therefore acted as a functional multi-dimensional restorative material with potential application in wound healing in vitro. PMID:25459982

  14. Prediction of the adhesive behavior of bio-inspired functionally graded materials against rough surfaces

    NASA Astrophysics Data System (ADS)

    Peijian, Chen; Juan, Peng; Yucheng, Zhao; Feng, Gao

    2014-06-01

    Roughness effect and adhesion properties are important characteristics to be accessed in the development of functionally graded materials for biological and biomimetic applications, particularly for the hierarchical composition in biomimetic gecko robot. A multi-asperities adhesion model to predict the adhesive forces is presented in this work. The effect of surface roughness and graded material properties, which significantly alter the adhesive strength between contact bodies, can be simultaneously considered in the generalized model. It is found that proper interfacial strength can be controlled by adjusting surface roughness σ / R, graded exponent k and material parameter E*R / Δγ. The results should be helpful in the design of new biomimetic materials and useful in application of micro functional instruments.

  15. Potential of the adhesion of bacteria isolated from drinking water to materials.

    PubMed

    Simões, Lúcia Chaves; Simões, Manuel; Oliveira, Rosário; Vieira, Maria João

    2007-04-01

    Heterotrophic bacteria (11 genera, 14 species, 25 putative strains) were isolated from drinking water, identified either biochemically or by partial 16s rDNA gene sequencing and their adherence characteristics were determined by two methods: i. thermodynamic prediction of adhesion potential by measuring hydrophobicity (contact angle measurements) and ii. by measuring adherence to eight different substrata (ASI 304 and 316 stainless steel, copper, polyvinyl chloride, polypropylene, polyethylene, silicone and glass). All the test organisms were hydrophilic and inter-species variation in hydrophobicity occurred only for Comamonas acidovorans. Stainless steel 304 (SS 304), copper, polypropylene (PP), polyethylene (PE) and silicone thermodynamically favoured adhesion for the majority of test strains (>18/25), whilst adhesion was generally less thermodynamically favorable for stainless steel 316 (SS 316), polyvinyl chloride (PVC) and glass. The predictability of thermodynamic adhesion test methods was validated by comparison with 24-well microtiter plate assays using nine reference strains and three adhesion surfaces (SS 316, PVC and PE). Results for Acinetobacter calcoaceticus, Burkolderia cepacia and Stenotrophomonas maltophilia sp. 2 were congruent between both methods whilst they differed for the other bacteria to at least one material. Only A. calcoaceticus had strongly adherent properties to the three tested surfaces. Strain variation in adhesion ability was detected only for Sphingomonas capsulata. Analysis of adhesion demonstrated that in addition to physicochemical surface properties of bacterium and substratum, biological factors are involved in early adhesion processes, suggesting that reliance on thermodynamic approaches alone may not accurately predict adhesion capacity. PMID:17440920

  16. OPTIMIZATION AND TESTING OF HIGHWAY MATERIALS TO MITIGATE ICE ADHESION

    EPA Science Inventory

    Field tests at the WSU Pavement Test Facility augment BBRC laboratory tests with comparative results. Factors of concern included pavement type, tire type, environment and toxicity, wear, ice/snow adhesion and asphalt overlays which included the substances as a component of the m...

  17. Rapid adhesive bonding and field repair of aerospace materials

    NASA Technical Reports Server (NTRS)

    Stein, B. A.

    1985-01-01

    Adhesive bonding in the aerospace industry typically utilizes autoclaves or presses which have considerable thermal mass. As a consequence, the rates of heatup and cooldown of the bonded parts are limited and the total time and cost of the bonding process are often relatively high. Many of the adhesives themselves do not inherently require long processing times. Bonding could be performed rapidly if the heat was concentrated in the bond lines or at least in the adherends. Rapid Adhesive Bonding concepts are developed to utilize induction heating techniques to provide heat directly to the bond line and/or adherends without heating the entire structure, supports, and fixtures of a bonding assembly. Bonding times for specimens can be cut by a factor of 10 to 100 compared to standard press or autoclave bonding. The development of Rapid Adhesive Bonding for lap shear specimens (per ASTM D1002 and D3163), for aerospace panel or component bonding, and for field repair needs of metallic and advanced fiber reinforced polymeric-matrix composite structures is reviewed. Equipment and procedures are described for bonding and repairing thin sheets, simple geometries, and honeycomb core panels.

  18. Evaluation of Microleakage of Silorane and Methacrylate Based Composite Materials in Class I Restorations by Using Two Different Bonding Techniques

    PubMed Central

    Alshetili, Mohsen S; Aldeyab, Sultan S

    2015-01-01

    Background: To evaluate the microleakage of silorane-based composite material (Filtek P90) with that of two homologous methacrylate-based composites materials (Filtek Z250 and Filtek Z250 XT), by using two different bonding techniques. Materials and Methods: Sixty extracted human maxillary first premolars prepared for standardized Class I cavities (4 mm × 2 mm × 2 mm) were randomly divided into three groups. Group A (n = 20) was filled with Filtek Z250 (Methacrylate) using single bond universal total etching technique, Group B (n = 20) was filled with Filtek Z250 XT (Methacrylate) using single bond universal self-etching technique and Group C (n = 20) restored with Filtek P90 (Silorane) with dedicated two-step self-etching prime and bond adhesive system (P90 system adhesive). Teeth were subjected to thermocycling regime (500×, 5-55°C), and dye penetration by immersing in 2% methylene blue for 24 h. Tooth sectioning was performed, and extent of the dye penetration was scored based on dye penetration scale to evaluate the microleakage. Statistical analysis included descriptive statistics and inferential statistics of Kruskal–Wallis test to compare the mean ranks between groups. Results: There was no significant difference observed for microleakage among the three composite materials tested in the present study. However, the cavities restored with silorane (Filtek P90) based composite displayed higher microleakage than the Filtek Z250, Z250 XT. Conclusion: All the restorative systems tested in this study exhibited microleakage, but the silorane technology showed more microleakage when compared to the methacrylate-based composite systems. PMID:26668473

  19. Shear bond strength of provisional restoration materials repaired with light-cured resins.

    PubMed

    Chen, Hsiu-Lin; Lai, Yu-lin; Chou, I-chiang; Hu, Chiung-Jen; Lee, Shyh-yuan

    2008-01-01

    This study evaluated the repair bond strengths of light-cured resins to provisional restoration materials with different chemical compositions and polymerization techniques. Fifty discs (10 mm in diameter and 1.5 mm thick) were fabricated for each provisional resin base material, including a self-cured methacrylate (Alike), self-cured bis-acrylate (Protemp 3 Garant), light-cured bis-acrylate (Revotek LC) and a heat-cured methacrylate (Namilon). All specimens were stored in distilled water at 37 degrees C for seven days before undergoing repair with one of four light-cured resins, including AddOn, Revotek LC, Dyractflow and Unifast LC and a self-cured resin (Alike), according to the manufacturers' instructions, for a total of 200 specimens. After 24 hours of storage in 37 degrees C water, the shear bond strengths were measured with a universal testing machine and fracture surfaces were examined under a stereomicroscope. Two-way ANOVA revealed that provisional resin-base material (p < 0.001), repair material (p < 0.001) and their interactions (p < 0.001) significantly affected the repair strength. Tukey's multiple comparisons showed that the lowest bonding strengths were found in specimens of heat-cured methacrylate resin materials repaired with bis-acryl resins, with their failure modes primarily being of the adhesive type. The highest bond strengths were recorded when the provisional resin-base materials and repairing resins had similar chemical components and the failure modes tended to be of the cohesive type. PMID:18833857

  20. The development of ecologically appropriate plant materials for restoration applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Restoration targets are increasingly the novel ecosystems that are rapidly becoming the planetary norm. To be effective, ecological restoration should emphasize ecosystem repair of past damage. When that damage is extensive, local genotypes may not be the ones most effective for repair. 'Local ha...

  1. Evidence for a material gradient in the adhesive tarsal setae of the ladybird beetle Coccinella septempunctata.

    PubMed

    Peisker, Henrik; Michels, Jan; Gorb, Stanislav N

    2013-01-01

    For an insect to be able to efficiently attach to surfaces, the adhesive pads on the distal parts of its legs must establish large contact areas. In case of hairy adhesive pads this requires flexibility of the contact-forming bristles, called adhesive tarsal setae. However, too flexible setae would have a low mechanical stability resulting in a decreased attachment ability of the pads. Here we show that the adhesive tarsal setae of the ladybird beetle Coccinella septempunctata feature pronounced gradients in the material composition and properties along their length. The Young's modulus ranges from 1.2 MPa at the tips, where we found the incorporation of high proportions of the elastic protein resilin, to 6.8 GPa at the bases of the setae. These gradients likely represent an evolutionary optimization, which increases the performance of the adhesive system by enabling effective adaptation to rough surfaces while simultaneously preventing lateral collapse of the setae. PMID:23552076

  2. Evidence for a material gradient in the adhesive tarsal setae of the ladybird beetle Coccinella septempunctata

    NASA Astrophysics Data System (ADS)

    Peisker, Henrik; Michels, Jan; Gorb, Stanislav N.

    2013-04-01

    For an insect to be able to efficiently attach to surfaces, the adhesive pads on the distal parts of its legs must establish large contact areas. In case of hairy adhesive pads this requires flexibility of the contact-forming bristles, called adhesive tarsal setae. However, too flexible setae would have a low mechanical stability resulting in a decreased attachment ability of the pads. Here we show that the adhesive tarsal setae of the ladybird beetle Coccinella septempunctata feature pronounced gradients in the material composition and properties along their length. The Young’s modulus ranges from 1.2 MPa at the tips, where we found the incorporation of high proportions of the elastic protein resilin, to 6.8 GPa at the bases of the setae. These gradients likely represent an evolutionary optimization, which increases the performance of the adhesive system by enabling effective adaptation to rough surfaces while simultaneously preventing lateral collapse of the setae.

  3. Materials research for High Speed Civil Transport and generic hypersonics: Adhesive durability

    NASA Technical Reports Server (NTRS)

    Allen, Mark R.

    1995-01-01

    This report covers a portion of an ongoing investigation of the durability of adhesives for the High Speed Civil Transport (HSCT) program. Candidate HSCT adhesives need to possess the high-temperature capability required for supersonic flight. This program was designed to initiate an understanding of the behavior of candidate HSCT materials when subjected to combined mechanical and thermal loads. Two adhesives (K3A and FM57) and two adherends (IM7/K3B polymeric composite and the titanium alloy Ti-6Al-4V) were used to fabricate thick adherend lap shear specimens. Due to processing problems, only the FM57/titanium bonds could be fabricated successfully. These are currently undergoing thermomechanical fatigue (TMF) testing. There is an acute need for an adhesive to secondarily bond polymeric composite adherends or, alternately, polymeric composites that remain stable at the processing temperatures of today's adhesives.

  4. Machinable glass-ceramics forming as a restorative dental material.

    PubMed

    Chaysuwan, Duangrudee; Sirinukunwattana, Krongkarn; Kanchanatawewat, Kanchana; Heness, Greg; Yamashita, Kimihiro

    2011-01-01

    MgO, SiO(2), Al(2)O(3), MgF(2), CaF(2), CaCO(3), SrCO(3), and P(2)O(5) were used to prepare glass-ceramics for restorative dental materials. Thermal properties, phases, microstructures and hardness were characterized by DTA, XRD, SEM and Vickers microhardness. Three-point bending strength and fracture toughness were applied by UTM according to ISO 6872: 1997(E). XRD showed that the glass crystallized at 892°C (second crystallization temperature+20°C) for 3 hrs consisted mainly of calcium-mica and fluorapatite crystalline phases. Average hardness (3.70 GPa) closely matched human enamel (3.20 GPa). The higher fracture toughness (2.04 MPa√m) combined with the hardness to give a lower brittleness index (1.81 µm(-1/2)) which indicates that they have exceptional machinability. Bending strength results (176.61 MPa) were analyzed by Weibull analysis to determine modulus value (m=17.80). Machinability of the calcium mica-fluorapatite glass-ceramic was demonstrated by fabricating with CAD/CAM. PMID:21597218

  5. The bond strength of elastomer tray adhesives to thermoplastic and acrylic resin tray materials.

    PubMed

    Hogans, W R; Agar, J R

    1992-04-01

    This study evaluated the bond strength of selected impression materials (Permlastic, Express, and Hydrosil) to a thermoplastic custom tray material as a function of drying time of the adhesive after application to a tray material. In addition, bond strengths of a polysulfide impression material to an acrylic resin tray material and to a thermoplastic tray material made directly against wax were evaluated. Bond strengths were obtained directly from values of applied load at failure and important conclusions were drawn. PMID:1507140

  6. Compressive fatigue limit of four types of dental restorative materials.

    PubMed

    Chen, Song; Öhman, Caroline; Jefferies, Steven R; Gray, Holly; Xia, Wei; Engqvist, Håkan

    2016-08-01

    The purpose of this study was to evaluate the quasi-static compressive strength and the compressive fatigue limit of four different dental restorative materials, before and after aging in distilled water for 30 days. A conventional glass ionomer cement (Fuji IX GP; IG), a zinc-reinforced glass ionomer cement (Chemfil rock; CF), a light curable resin-reinforced glass ionomer cement (Fuji II LC; LC) and a resin-based composite (Quixfil; QF) were investigated. Cylindrical specimens (4mm in diameter and 6mm in height) were prepared according to the manufacturer׳s instructions. The compressive fatigue limit was obtained using the staircase method. Samples were tested in distilled water at 37°C, at a frequency of 10Hz with 10(5) cycles set as run-out. 17 fatigue samples were tested for each group. Two-way ANOVA and one-way ANOVA followed by Tukey׳s post-hoc test were used to analyze the results. Among the four types of materials, the resin-based composite exhibited the highest compressive strength (244±13.0MPa) and compressive fatigue limit (134±7.8MPa), followed by the light-cured resin reinforced glass ionomer cement (168±8.5MPa and 92±6.6MPa, respectively) after one day of storage in distilled water. After being stored for 30 days, all specimens showed an increase in compressive strength. Aging showed no effect on the compressive fatigue limit of the resin-based composite and the light-cured resin reinforced glass ionomer cement, however, the conventional glass ionomer cements showed a drastic decrease (37% for IG, 31% for CF) in compressive fatigue limit. In conclusion, in the present study, resin modified GIC and resin-based composite were found to have superior mechanical properties to conventional GIC. PMID:27085845

  7. Comparative wear resistance of reinforced glass ionomer restorative materials.

    PubMed

    Yap, A U; Teo, J C; Teoh, S H

    2001-01-01

    This study investigated the wear resistance of three restorative reinforced glass ionomer cements (Fuji IX GP FAST [FJ], Miracle Mix [MM] and Ketac Silver [KS]). Microfilled (Silux [SX]) and mini-filled (Z100 [ZO]) composites were used for comparison. Six specimens were made for each material. The specimens were conditioned for one week in distilled water at 37 degrees C and subjected to wear testing at 20 MPa contact stress against SS304 counterbodies using a reciprocal compression-sliding wear instrumentation. Distilled water was used as lubricant. Wear depth (microm) was measured using profilometry every 2,000 cycles up to 10,000 cycles. Results were analyzed using ANOVA/Scheffe's test (p<0.05). After 10,000 cycles of wear testing, ranking was as follows: KS>ZO>MM>FJ>SX. Wear ranged from 26.1 microm for SX to 71.5 microm for KS. The wear resistance of KS was significantly lower than FJ, MM and SX at all wear intervals. Although KS had significantly more wear than ZO at 2,000 to 6,000 cycles, no significant difference in wear was observed between these two materials at 8,000 and 10,000 cycles. Sintering of silver particles to glass ionomer cement (KS) did not appear to improve wear resistance. The simple addition of amalgam alloy to glass ionomer may improve wear resistance but results in poor aesthetics (silver-black color). FJ, which relies on improved chemistry instead of metal fillers, showed comparable wear resistance to the composites evaluated and is tooth-colored. It may serve as a potential substitute for composites in low-stress situations where fluoride release is desirable and aesthetic requirements are not high. PMID:11504433

  8. Surface characteristics of aesthetic restorative materials - an SEM study.

    PubMed

    Bagheri, R; Burrow, M F; Tyas, M J

    2007-01-01

    To determine the degree of surface roughness of glass-ionomer cements (GICs) and polyacid-modified resin composite (PAMRC) after polishing and immersion in various foodstuffs. Three tooth-coloured restorative materials were used: a PAMRC (F2000), a conventional glass-ionomer cement (CGIC) (Fuji IX) and a resin-modified glass-ionomer cements (RM-GIC) (Fuji II LC). Disk-shaped specimens were prepared and tested with either a plastics matrix finish or after polishing with wet silicon carbide papers up to 2000-grit. All specimens were immersed in 37 degrees C-distilled water for 1 week, followed by three different foodstuffs (red wine, coffee or tea) for a further 2 weeks. Replicas of specimens were prepared by taking polyvinyl siloxane impressions, casting in epoxy resin, gold sputter-coating and examining using a Field-Emission Scanning Electron Microscope. The polished and matrix finish specimens of F2000 showed many microcracks at low magnification, and eroded surfaces with missing and protruding particles at high magnification in the polished specimens. The surface-polished specimens of Fuji II LC were considerably rougher than the matrix-finish specimens, with large voids and protruding filler particles. The effects of foodstuffs on Fuji II LC and F2000 were not noticeable. The CGIC became noticeably rougher after exposure to coffee and tea. All specimens had the smoothest surface when they were cured against a plastics matrix strip, and all materials had a rougher surface after polishing. None of the foodstuffs produced a perceptible increase in roughness on RM-GIC and PAMRC surfaces, whereas coffee and tea markedly increased the surface roughness of Fuji IX. PMID:17207080

  9. Tuning the material-cytoskeleton crosstalk via nanoconfinement of focal adhesions.

    PubMed

    Natale, Carlo F; Ventre, Maurizio; Netti, Paolo A

    2014-03-01

    Material features proved to exert a potent influence on cell behaviour in terms of adhesion, migration and differentiation. In particular, biophysical and biochemical signals on material surfaces are able to affect focal adhesion distribution and cytoskeletal assemblies, which are known to regulate signalling pathways that ultimately influence cell fate and functions. However, a general, unifying model that correlates cytoskeletal-generated forces with genetic events has yet to be developed. Therefore, it is crucial to gain a better insight into the material-cytoskeleton crosstalk in order to design and fabricate biomaterials able to govern cell fate more accurately. In this work, we demonstrate that confining focal adhesion distribution and growth dramatically alters the cytoskeleton's structures and dynamics, which in turn dictate cellular and nuclear shape and polarization. MC3T3 preosteoblasts were cultivated on nanograted polydimethylsiloxane substrates and a thorough quantification - in static and dynamic modes - of the morphological and structural features of focal adhesions and cytoskeleton was performed. Nanoengineered surfaces provided well-defined zones for focal adhesions to form and grow. Unique cytoskeletal structures spontaneously assembled when focal adhesions were confined and, in fact, they proved to be very effective in deforming the nuclei. The results here presented provide elements to engineer surfaces apt to guide and control cell behaviour through the material-cytoskeleton-nucleus axis. PMID:24388800

  10. Superhydrophobic gecko feet with high adhesive forces towards water and their bio-inspired materials

    NASA Astrophysics Data System (ADS)

    Liu, Kesong; Du, Jiexing; Wu, Juntao; Jiang, Lei

    2012-01-01

    Functional integration is an inherent characteristic for multiscale structures of biological materials. In this contribution, we first investigate the liquid-solid adhesive forces between water droplets and superhydrophobic gecko feet using a high-sensitivity micro-electromechanical balance system. It was found, in addition to the well-known solid-solid adhesion, the gecko foot, with a multiscale structure, possesses both superhydrophobic functionality and a high adhesive force towards water. The origin of the high adhesive forces of gecko feet to water could be attributed to the high density nanopillars that contact the water. Inspired by this, polyimide films with gecko-like multiscale structures were constructed by using anodic aluminum oxide templates, exhibiting superhydrophobicity and a strong adhesive force towards water. The static water contact angle is larger than 150° and the adhesive force to water is about 66 μN. The resultant gecko-inspired polyimide film can be used as a ``mechanical hand'' to snatch micro-liter liquids. We expect this work will provide the inspiration to reveal the mechanism of the high-adhesive superhydrophobic of geckos and extend the practical applications of polyimide materials.

  11. Superhydrophobic gecko feet with high adhesive forces towards water and their bio-inspired materials.

    PubMed

    Liu, Kesong; Du, Jiexing; Wu, Juntao; Jiang, Lei

    2012-02-01

    Functional integration is an inherent characteristic for multiscale structures of biological materials. In this contribution, we first investigate the liquid-solid adhesive forces between water droplets and superhydrophobic gecko feet using a high-sensitivity micro-electromechanical balance system. It was found, in addition to the well-known solid-solid adhesion, the gecko foot, with a multiscale structure, possesses both superhydrophobic functionality and a high adhesive force towards water. The origin of the high adhesive forces of gecko feet to water could be attributed to the high density nanopillars that contact the water. Inspired by this, polyimide films with gecko-like multiscale structures were constructed by using anodic aluminum oxide templates, exhibiting superhydrophobicity and a strong adhesive force towards water. The static water contact angle is larger than 150° and the adhesive force to water is about 66 μN. The resultant gecko-inspired polyimide film can be used as a "mechanical hand" to snatch micro-liter liquids. We expect this work will provide the inspiration to reveal the mechanism of the high-adhesive superhydrophobic of geckos and extend the practical applications of polyimide materials. PMID:22139414

  12. Repeated exposure of acidic beverages on esthetic restorative materials: An in-vitro surface microhardness study

    PubMed Central

    Sunny, Steffy M.; Rai, Kavita; Hegde, Amitha M.

    2016-01-01

    Background A manifold increase in the consumption of aerated beverages has witnessed a twin increase in tooth wear and raised demand for esthetic restorative materials. This study aimed to evaluate the surface microhardness changes of esthetic restorative materials following treatment with aerated beverages in an in-vitro situation. Material and Methods The initial surface microhardness of the restorative materials GC Fuji II LC, GC Fuji IX, Nano Glass ionomer, Resin and Nano composite was recorded. These materials were studied under 3 groups that included those exposed to the acidic beverages daily, weekly once in a month and those that had no exposures at all. The final surface microhardness of the materials was recorded following experimentation and was subjected to statistical comparisons. Results The restorative materials were compared for their surface microhardness changes following respective treatments using the T-test and One-way ANOVA analysis. Inter-comparisons between the groups showed statistical significance (p<.05), when treated with both the beverages. The five restorative materials revealed surface microhardness loss; the maximum reduction noticed with the Nano glass ionomer cement tested (p<.0005). Conclusions The surface microhardness of restorative materials markedly reduced upon repeated exposures with acidic beverages; the product with phosphoric acid producing the maximum surface microhardness loss. Key words:Restorative materials, acidic beverages, surface microhardness, resin composites, glass ionomers. PMID:27398183

  13. Effects of elevated temperatures on different restorative materials: An aid to forensic identification processes

    PubMed Central

    Pol, Chetan A.; Ghige, Suvarna K.; Gosavi, Suchitra R.; Hazarey, Vinay K.

    2015-01-01

    Background: Heat-induced alterations to dental and restorative materials can be of great interest to forensic dentistry. Knowing the specific optical behavior of dental materials can be of high importance as recognition of changes induced by high temperatures can lead to the determination of material which was used in a dental restoration, facilitating identification of burned human remains. Aim: To observe the effects of predetermined temperatures (200°C–400°C–600°C–800°C–1000°C) on unrestored teeth and different restorative materials macroscopically and then examine them under a stereomicroscope for the purpose of identification. Materials and Methods: The study was conducted on 375 extracted teeth which were divided into five groups of 75 teeth each as follows: group 1- unrestored teeth, group 2- teeth restored with all-ceramic crowns, Group 3- with class I silver amalgam filling, group 4- with class I composite restoration, and group 5- with class I glass ionomer cement restoration. Results: Unrestored and restored teeth display a series of specific macroscopic & stereomicroscopic structural changes for each range of temperature. Conclusion: Dental tissues and restorative materials undergo a series of changes which correlate well with the various temperatures to which they were exposed. These changes are a consequence of the nature of the materials and their physicochemical characteristics. PMID:26005305

  14. Restorative material and other tooth-specific variables associated with the decision to repair or replace defective restorations: findings from The Dental PBRN

    PubMed Central

    Gordan, Valeria V.; Riley, Joseph L.; Worley, Donald C.; Gilbert, Gregg H.

    2012-01-01

    Objectives Using data from dentists participating in The Dental Practice-Based Research Network (DPBRN), the study had 2 main objectives: (1) to identify and quantify the types of restorative materials in the existing failed restorations; and (2) to identify and quantify the materials used to repair or replace those failed restorations. Methods This cross-sectional study used a consecutive patient/restoration recruitment design. Practitioner-investigators recorded data on consecutive restorations in permanent teeth that needed repair or replacement. Data included the primary reason for repair or replacement, tooth surface(s) involved, restorative materials used, and patient demographics. Results Data for 9,875 restorations were collected from 7,502 patients in 197 practices for which 75% of restorations were replaced and 25% repaired. Most of the restorations that were either repaired or replaced were amalgam (56%) for which most (56%) of the material used was direct tooth-colored. The restorative material was 5 times more likely to be changed when the original restoration was amalgam (OR=5.2, p<.001). The likelihood of changing an amalgam restoration differed as a function of the tooth type (OR=3.0, p<.001), arch (OR=6.6, p<.001); and number of surfaces in the original restoration (OR=12.2, p<.001). Conclusion The probability of changing from amalgam to another restorative material differed with several characteristics of the original restoration. The change was most likely to take place when (1) the treatment was a replacement; (2) the tooth was not a molar; (3) the tooth was in the maxillary arch; and (4) the original restoration involved a single surface. PMID:22342563

  15. Material- and feature-dependent effects on cell adhesion to micro injection moulded medical polymers.

    PubMed

    Choi, Seong Ying; Habimana, Olivier; Flood, Peter; Reynaud, Emmanuel G; Rodriguez, Brian J; Zhang, Nan; Casey, Eoin; Gilchrist, Michael D

    2016-09-01

    Two polymers, polymethylmethacrylate (PMMA) and cyclic olefin copolymer (COC), containing a range of nano- to micron- roughness surfaces (Ra 0.01, 0.1, 0.4, 1.0, 2.0, 3.2 and 5.0μm) were fabricated using electrical discharge machining (EDM) and replicated using micro injection moulding (μIM). Polymer samples were characterized using optical profilometry, atomic force microscopy (AFM) and water surface contact angle. Cell adhesion tests were carried out using bacterial Pseudomonas fluorescens and mammalian Madin-Darby Canine Kidney (MDCK) cells to determine the effect of surface hydrophobicity, surface roughness and stiffness. It is found that there are features which gave insignificant differences (feature-dependent effect) in cell adhesion, albeit a significant difference in the physicochemical properties (material-dependent effect) of substrata. In bacterial cell adhesion, the strongest feature-dependence is found at Ra 0.4μm surfaces, with material-dependent effects strongest at Ra 0.01μm. Ra 0.1μm surfaces exhibited strongest feature-dependent effects and Ra 5.0μm has strongest material-dependent effects on mammalian cell adhesion. Bacterial cell adhesion is found to be favourable to hydrophobic surfaces (COC), with the lowest adhesion at Ra 0.4μm for both materials. Mammalian cell adhesion is lowest in Ra 0.1μm and highest in Ra 1.0μm, and generally favours hydrophilic surfaces (PMMA). These findings can be used as a basis for developing medical implants or microfluidic devices using micro injection moulding for diagnostic purposes, by tuning the cell adhesion on different areas containing different surface roughnesses on the diagnostic microfluidic devices or medical implants. PMID:27137802

  16. A metal–ion-responsive adhesive material via switching of molecular recognition properties

    PubMed Central

    Nakamura, Takashi; Takashima, Yoshinori; Hashidzume, Akihito; Yamaguchi, Hiroyasu; Harada, Akira

    2014-01-01

    Common adhesives stick to a wide range of materials immediately after they are applied to the surfaces. To prevent indiscriminate sticking, smart adhesive materials that adhere to a specific target surface only under particular conditions are desired. Here we report a polymer hydrogel modified with both β-cyclodextrin (βCD) and 2,2′-bipyridyl (bpy) moieties (βCD–bpy gel) as a functional adhesive material responding to metal ions as chemical stimuli. The adhesive property of βCD–bpy gel based on interfacial molecular recognition is expressed by complexation of metal ions to bpy that controlled dissociation of supramolecular cross-linking of βCD–bpy. Moreover, adhesion of βCD–bpy gel exhibits selectivity on the kinds of metal ions, depending on the efficiency of metal–bpy complexes in cross-linking. Transduction of two independent chemical signals (metal ions and host–guest interactions) is achieved in this adhesion system, which leads to the development of highly orthogonal macroscopic joining of multiple objects. PMID:25099995

  17. Conservative Approach for Restoring Posterior Missing Tooth with Fiber Reinforcement Materials: Four Clinical Reports

    PubMed Central

    Karaarslan, Emine Sirin; Ertas, Ertan; Ozsevik, Semih; Usumez, Aslihan

    2011-01-01

    Adhesively luted, fiber-reinforced, composite-inlay, retained fixed-partial dentures can be a clinical alternative for the replacement of missing posterior teeth in selective situations. This type of restoration allows for satisfactory esthetics and reduced tooth preparation compared to a conventional, fixed-partial denture. This clinical report describes the use of a fiber-reinforced, composite-inlay, retained fixed-partial denture as a conservative alternative for the replacement of missing posterior teeth. PMID:21912503

  18. A FIELD-TRIAL OF TWO RESTORATIVE MATERIALS USED WITH ATRAUMATIC RESTORATIVE TREATMENT IN RURAL TURKEY: 24-MONTH RESULTS

    PubMed Central

    Ercan, Ertugrul; Dülgergil, Ç. Türksel; Soyman, Mübin; Dalli, Mehmet; Yildirim, Isil

    2009-01-01

    Objective: The purpose of this study was to investigate the clinical performance of high-strength glass ionomer cement (HSGIC) and resin-modified glass ionomer (RMGIC) in single and multiple surface carious cavities in the field conditions. Material and Methods: A split-mouth design, including ninety-one fillings placed on contra lateral molar pairs of 37 children, was used in permanent dentition. As filling materials, a HSGIC (Ketac Molar/3M ESPE) and a RMGIC (Vitremer/ 3M ESPE) were used with the Atraumatic Restorative Treatment (ART). Baseline and 6, 12 and 24-month evaluations of the fillings were made with standard-ART and USPHS criteria by two examiners with kappa values of 0.92 and 0.87 for both criteria. Results: According to the USPHS criteria, the retention rates of RMGIC and HSGIC restorations were 100% and 80.9% for single surface, and 100% and 41.2% for multiple surface restorations after 24 months, respectively. Irrespective of surface number, RMGIC was significantly superior to HSGIC (p= 0.004), according to both standard-ART and USPHS criteria. Conclusion: The results indicate that RMGIC may be an alternative restorative technique in comparison to high-strength GIC applications in ART-field-trials. However, further clinical and field trials are needed to support this conclusion. PMID:19668990

  19. Physicochemical analysis of initial adhesion and biofilm formation of Methanosarcina barkeri on polymer support material.

    PubMed

    Nguyen, Vi; Karunakaran, Esther; Collins, Gavin; Biggs, Catherine A

    2016-07-01

    The retention of selective biofilms of Methanosarcina species within anaerobic digesters could reduce start-up times and enhance the efficiency of the process in treating high-strength domestic sewage. The objective of the study was to examine the effect of the surface characteristics of six common polymer support materials on the initial adhesion of the model methanogen, Methanosarcina barkeri, and to assess the potential of these support materials as selective biofilm carriers. Results from both the initial adhesion tests and extended DLVO (xDLVO) model correlated with each other, with PVC (12% surface coverage/mm(2)), PTFE (6% surface coverage/mm(2)), and PP (6% surface coverage/mm(2)), shown to be the better performing support materials for initial adhesion, as well as subsequent biofilm formation by M. barkeri after 72h. Experimental results of these three support materials showed that the type of material strongly influenced the extent of adhesion from M. barkeri (p<0.0001), and the xDLVO model was able to explain the results in these environmental conditions. Therefore, DLVO physicochemical forces were found to be influential on the initial adhesion of M. barkeri. Scanning electron microscopy suggested that production of extracellular polymeric substances (EPS) from M. barkeri could facilitate further biofilm development. This study highlights the potential of using the xDLVO model to rapidly identify suitable materials for the selective adhesion of M. barkeri, which could be beneficial in both the start-up and long-term phases of anaerobic digestion. PMID:27038917

  20. Surface topography of composite restorative materials following ultrasonic scaling and its Impact on bacterial plaque accumulation. An in-vitro SEM study

    PubMed Central

    Hossam, A. Eid; Rafi, A. Togoo; Ahmed, A Saleh; Sumanth, Phani CR

    2013-01-01

    Background: This is an in vitro study to investigate the effects of ultrasonic scaling on the surface roughness and quantitative bacterial count on four different types of commonly used composite restorative materials for class V cavities. Materials & Methods: Nanofilled, hybrid, silorane and flowable composites were tested. Forty extracted teeth served as specimen and were divided into 4 groups of 10 specimens, with each group receiving a different treatment and were examined by a Field emission scanning electron microscope. Bacterial suspension was then added to the pellicle-coated specimens, and then bacterial adhesion was analyzed by using image analyzing program. Results: Flowable and silorane-based composites showed considerably smoother surfaces and lesser bacterial count in comparison to other types, proving that bacterial adhesion is directly proportional to surface roughness. Conclusion: The use of ultrasonic scalers affects the surfaces of composite restorative materials. Routine periodontal scaling should be carried out very carefully, and polishing of the scaled surfaces may overcome the alterations in roughness, thus preventing secondary caries, surface staining, plaque accumulation and subsequent periodontal inflammation. How to cite this article: Eid H A, Togoo R A, Saleh A A, Sumanth C R. Surface Topography of Composite Restorative Materials following Ultrasonic Scaling and its Impact on Bacterial Plaque Accumulation. An In-Vitro SEM Study. J Int Oral Health 2013; 5(3):13-19. PMID:24155597

  1. Escherichia coli adhesion, biofilm development and antibiotic susceptibility on biomedical materials.

    PubMed

    Gomes, L C; Silva, L N; Simões, M; Melo, L F; Mergulhão, F J

    2015-04-01

    The aim of this work was to test materials typically used in the construction of medical devices regarding their influence in the initial adhesion, biofilm development and antibiotic susceptibility of Escherichia coli biofilms. Adhesion and biofilm development was monitored in 12-well microtiter plates containing coupons of different biomedical materials--silicone (SIL), stainless steel (SS) and polyvinyl chloride (PVC)--and glass (GLA) as control. The susceptibility of biofilms to ciprofloxacin and ampicillin was assessed, and the antibiotic effect in cell morphology was observed by scanning electron microscopy. The surface hydrophobicity of the bacterial strain and materials was also evaluated from contact angle measurements. Surface hydrophobicity was related with initial E. coli adhesion and subsequent biofilm development. Hydrophobic materials, such as SIL, SS, and PVC, showed higher bacterial colonization than the hydrophilic GLA. Silicone was the surface with the greatest number of adhered cells and the biofilms formed on this material were also less susceptible to both antibiotics. It was found that different antibiotics induced different levels of elongation on E. coli sessile cells. Results revealed that, by affecting the initial adhesion, the surface properties of a given material can modulate biofilm buildup and interfere with the outcome of antimicrobial therapy. These findings raise the possibility of fine-tuning surface properties as a strategy to reach higher therapeutic efficacy. PMID:25044887

  2. Modeling and analysis of electrostatic adhesion force for climbing robot on dielectric wall materials

    NASA Astrophysics Data System (ADS)

    Mao, Jiu-Bing; Qin, Lan; Zhang, Wan-Xiong; Xie, Li; Wang, Yong

    2015-01-01

    In recent years, electrostatic adhesion technology on the wall climbing robots has attracted many researchers interest for its outstanding characteristics. In this paper, a theoretical analytical model is derived from the electrostatic adhesion field between the dielectric wall and a coplanar array of parallel strip electrodes called inter-digital electrodes (IDE). Due to the polarization on the different dielectric being complicated, the field is divided into four layers in order to obtain corresponding boundaries. Besides, the roughness of the wall surface, alternately polarities applied voltages and different dielectric parameter with different layer, all of which are also taken into account in the model since they have a significant influence on the electrostatic adhesion field. Based on this model, the electrostatic adhesion force (EAF) is calculated utilizing the Maxwell stress tensor (MST) formulation. As we all known, EAF is vital to the climbing robot design. Specially, it is possible for us to optimize the load to weight ratio in next step. Through comparing the finite element method (FEM) simulation with theoretical computation, the simulation and calculated data show that our proposed scheme can achieve desired results. Moreover, experiments of electrostatic adhesion performance for the adhesive on some different dielectric materials are also implemented.

  3. Comparing Adhesive Bonding and LAMP Joining Technology in Case of Hybrid Material Combination

    NASA Astrophysics Data System (ADS)

    Markovits, T.; Bauernhuber, A.

    As plastics are utilized more and more frequently in our devices, it becomes necessary that they can be adequately joined to other materials, like metals. Bonding different materials was carried so far out primarily by adhesives, however, novel technologies, like laser assisted metal-plastic joining are showing benefits against current technologies. In the course of this study, the authors joined PMMA plastic to structural steel by adhesives and by laser assisted metal-plastic joining. Mechanical tests were carried out to compare the two different technologies, and to be able to position the LAMP joining within the field of joining technologies. Results show clearly the advantages of laser transmission joining as compared to adhesives.

  4. Guidelines for Preservation, Conservation, and Restoration of Local History and Local Genealogical Materials.

    ERIC Educational Resources Information Center

    RQ, 1993

    1993-01-01

    Presents guidelines adopted by the American Library Association (ALA) relating to the preservation, conservation, and restoration of local history and local genealogical materials. Topics addressed include assessing preservation needs; developing a plan; choosing appropriate techniques, including microduplication, photoduplication, electronic…

  5. Measurement of the fluorescence of restorative dental materials using a 655-nm diode laser

    NASA Astrophysics Data System (ADS)

    Zanin, Fatima A. A.; Souza-Campos, Dilma H.; Zanin, Sissi; Brugnera, Aldo, Jr.; Pecora, Jesus D.; Pinheiro, Antonio L. B.; Harari, Sonia

    2001-04-01

    The aim of this study was to determine the level of fluorescence of seven restorative materials using 655 nm diode laser. The laser fluorescence system has ben used as an auxiliary method for the detection of carious lesions. This new diagnostic method increases information which are important for the choice of treatment by the Dentist. The characteristic of restorative materials and sealers interferes in the values obtained by the apparatus during the detection of secondary carious lesions. The optical properties of each biological tissue or material are related to the interaction with the laser beam. Aware of that, the fluorescence of healthy dentin and enamel is 0-15, the authors determined the fluorescence of seven restorative materials with 10 teeth in each group. The laser reading scale differed according to the materia, ranging from 1 to 22 with several materials, for example the sealer without inorganic filler and the glass ionomer, showing fluorescence values similar to carious enamel which interferes with the readings around the restorations resulting in a false positive. Knowledge of restoration material fluorescence can aid in the detection of secondary carious lesions around the restorations.

  6. Effect of the lasers used in periodontal therapy on the surfaces of restorative materials.

    PubMed

    Hatipoğlu, Mükerrem; Barutcigil, Çağatay; Harorlı, Osman Tolga; Ulug, Bülent

    2016-05-01

    The present study aimed to reveal potential damage of the lasers, which are used as an alternative to manual instruments in periodontal therapy, might cause to the surface of restorative materials. Four different restorative materials were used: a glass-ionomer cement (GIC), a flowable composite (FC), a universal composite (UC) and an amalgam. Ten cylindrical samples (8 mm × 2 mm) were prepared for each restorative material. Two laser systems were used in subgingival curettage mode; an 940 nm diode laser (Epic Biolase, Irvine, CA) and an Er,Cr:YSGG laser (Waterlase iPlus, Biolase, Irvine, CA). After laser irradiation, roughness of the sample surfaces was measured using a profilometer. Additionally, atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses were performed to evaluate the morphology and surface deformations of the restorative materials and surfaces. The laser irradiation did not affect the surface roughness of any restorative materials relative to that of the control group (p > 0.05) except for the Er,Cr:YSGG treatment on GIC (p < 0.05). SEM and AFM images verified the results of the surface roughness tests. Within the limitations of the present study, it was demonstrated that Er,Cr:YSGG and diode lasers, aside from the Er;Cr:YSGG treatment on GIC, caused no harmful surface effects on adjacent restorative materials. SCANNING 38:227-233, 2016. © 2015 Wiley Periodicals, Inc. PMID:26340579

  7. [Effect of water storage and intrapulpal pressure on microleakage of three restorative materials].

    PubMed

    Balogh, A E; Bouter, D; Fazekas, A; Degrange, M

    2000-09-01

    Three different restorative materials, Z100 composite, F2000 compomer and Vitremer glass ionomer cement are currently proposed for Class V restorations. The aim of this in vitro study was to evaluate the influence of water storage and the simulated intrapulpal pressure (sIP) on the quality of the margins of class V restorations located both in enamel and dentin. The water resorption of restorative materials containing hydrophilic groups (compomers and glass ionomer cements) can favourably modify the marginal sealing ability by hydroscopic expansion. The influence of the sIP was specific to the material. While F2000 compomer and Vitremer glass ionomer cement were un-influenced by sIP, with Z100 composite a significant difference could be observed. It was concluded that F2000 compomer and Vitremer glass ionomer cement showed significantly less microleakage, which means a better marginal sealing ability than Z100 composite. PMID:11057023

  8. Permeability testing of composite material and adhesive bonds for the DC-XA composite feedline program

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    1995-01-01

    Hercules IM7/8552 carbon/epoxy and Hysol EA 9394 epoxy adhesive bonded between composite/titanium were tested for permeability after various numbers of thermal cycles between 100 C and liquid nitrogen (-196 C). The specimens were quenched from the 100 C temperature into liquid nitrogen to induce thermal shock into the material. Results showed that the carbon/epoxy system was practically impermeable even after 12 thermal cycles. The EA 9394 adhesive bondline was more permeable than the carbon/epoxy, but vacuum mixing minimized the permeability and kept it within allowable limits. Thermal cycling had little effect on the permeability values of the bondline specimens.

  9. Effects of interlayer thickness and the substrate material on the adhesion properties of CrZrN coatings

    NASA Astrophysics Data System (ADS)

    Kim, Kyu-Sung; Kim, Hoe-Kun; La, Joung-Hyun; Lee, Sang-Yul

    2016-01-01

    To confirm the influence of the interlayer thickness and substrate material on adhesion properties, CrZrN coatings with various Cr interlayer thickness were deposited on AISI H13, high speed steel, and tungsten carbide using unbalanced magnetron sputtering. The adhesion strength showed maximum value at 300 nm of the interlayer, but as the interlayer increased further to 450 nm, the adhesion strength decreased. The adhesion properties of the coatings were dependent upon not only interlayer thickness but also the substrate materials. The adhesion strength of the coating were measured 12, 32, 53 N on the tungsten carbide, AISI H13 steel, high speed steel, respectively and three different failure modes such as buckling spallation, wedging spallation, and chipping were observed on each substrate. The difference in adhesion properties could be attributed to the difference in value of elastic strain to failure (H/E) among the CrZrN coating, the interlayer, and the substrates material.

  10. Marginal microleakage of cervical composite resin restorations bonded using etch-and-rinse and self-etch adhesives: two dimensional vs. three dimensional methods

    PubMed Central

    Khoroushi, Maryam

    2016-01-01

    Objectives This study was evaluated the marginal microleakage of two different adhesive systems before and after aging with two different dye penetration techniques. Materials and Methods Class V cavities were prepared on the buccal and lingual surfaces of 48 human molars. Clearfil SE Bond and Single Bond (self-etching and etch-and-rinse systems, respectively) were applied, each to half of the prepared cavities, which were restored with composite resin. Half of the specimens in each group underwent 10,000 cycles of thermocycling. Microleakage was evaluated using two dimensional (2D) and three dimensional (3D) dye penetration techniques separately for each half of each specimen. Data were analyzed with SPSS 11.5 (SPSS Inc.), using the Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Results The difference between the 2D and 3D microleakage evaluation techniques was significant at the occlusal margins of Single bond groups (p = 0.002). The differences between 2D and 3D microleakage evaluation techniques were significant at both the occlusal and cervical margins of Clearfil SE Bond groups (p = 0.017 and p = 0.002, respectively). The difference between the 2D and 3D techniques was significant at the occlusal margins of non-aged groups (p = 0.003). The difference between these two techniques was significant at the occlusal margins of the aged groups (p = 0.001). The Mann-Whitney test showed significant differences between the two techniques only at the occlusal margins in all specimens. Conclusions Under the limitations of the present study, it can be concluded that the 3D technique has the capacity to detect occlusal microleakage more precisely than the 2D technique. PMID:27200275

  11. High-Temperature Structures, Adhesives, and Advanced Thermal Protection Materials for Next-Generation Aeroshell Design

    NASA Technical Reports Server (NTRS)

    Collins, Timothy J.; Congdon, William M.; Smeltzer, Stanley S.; Whitley, Karen S.

    2005-01-01

    The next generation of planetary exploration vehicles will rely heavily on robust aero-assist technologies, especially those that include aerocapture. This paper provides an overview of an ongoing development program, led by NASA Langley Research Center (LaRC) and aimed at introducing high-temperature structures, adhesives, and advanced thermal protection system (TPS) materials into the aeroshell design process. The purpose of this work is to demonstrate TPS materials that can withstand the higher heating rates of NASA's next generation planetary missions, and to validate high-temperature structures and adhesives that can reduce required TPS thickness and total aeroshell mass, thus allowing for larger science payloads. The effort described consists of parallel work in several advanced aeroshell technology areas. The areas of work include high-temperature adhesives, high-temperature composite materials, advanced ablator (TPS) materials, sub-scale demonstration test articles, and aeroshell modeling and analysis. The status of screening test results for a broad selection of available higher-temperature adhesives is presented. It appears that at least one (and perhaps a few) adhesives have working temperatures ranging from 315-400 C (600-750 F), and are suitable for TPS-to-structure bondline temperatures that are significantly above the traditional allowable of 250 C (482 F). The status of mechanical testing of advanced high-temperature composite materials is also summarized. To date, these tests indicate the potential for good material performance at temperatures of at least 600 F. Application of these materials and adhesives to aeroshell systems that incorporate advanced TPS materials may reduce aeroshell TPS mass by 15% - 30%. A brief outline is given of work scheduled for completion in 2006 that will include fabrication and testing of large panels and subscale aeroshell test articles at the Solar-Tower Test Facility located at Kirtland AFB and operated by Sandia

  12. Effect of a new resin inlay/onlay restorative material on cuspal reinforcement.

    PubMed

    Lopes, L M; Leitao, J G; Douglas, W H

    1991-08-01

    Nine maxillary premolars were restored with composite resin inlays involving large intracoronal cavity preparations. Buccal and lingual bonded strain guages measured the cuspal flexure under a carefully controlled application of occlusal force. The intact tooth was compared with the corresponding preparation and final restoration. The preparation itself greatly reduced the coronal rigidity, but this was completely recovered in the restored tooth, within the functional force of 111 N. A stiffness ratio showed a 97% recovery. From the point of view of cuspal strength, this may mean that larger intracoronal restorations are feasible with this type of restoration. However, other factors, such as chairside time and complexity, and material properties, such as occlusal wear, have to be taken into consideration. PMID:1882059

  13. Physical gas discharge procedure for adhesive surface pretreatment of polymer composite materials

    NASA Astrophysics Data System (ADS)

    Hahn, O.; Huesgen, B.

    The effects of corona discharge and low-pressure plasma treatments are examined with respect to the preparation of the adhesive surfaces of polymer composites. A glass-fiber-reinforced polyamide and an epoxy-based structural adhesive are employed and treated with the physical gas-discharge procedure. Attention is given to the wettability of the polymer surface and to the adhesive strengths of the joints for the two pretreatment procedures. Diagrams show the dependence of bonding strength and constant contact angle on the duration, performance, and storage times of the corona and plasma treatments. SEM is used to study the surface characteristics of the materials, and decomposition products are noted in the surfaces of the joints. Plasma treatments generally lead to more effective bonds in the polyamide specimens, and the corona-discharge treatment leads to good bonds with some surface modifications.

  14. Adhesion of finely dispersed particles to the surface of coating materials

    SciTech Connect

    Petryanov, I.V.; Lyashkevich, I.M.; Sadovskii, B.F.; Chernaya, L.G.; Chernyaeva, G.A.

    1986-12-01

    It was established experimentally that compressed gypsums with added organosilicon liquids GKZh-10 and GKZh-94 have the lowest values of the molecular and capillary components of adhesive strength of particles to surface. The specific bulk and surface electrical conductivities of natural marble are 3-4 orders of magnitude greater than those of the gypsums. Thus the high-strength gypsums with the special additives have significantly lower adhesive strength toward dust particles than does natural marble. The dependence of the adhesive properties of materials on surface structure was estimated by scanning electron microscopy. The dust-retentive capability of the sample surfaces was determined by blow-off of precipitated particles by a current of filtered air.

  15. Comparison of VOC and ammonia emissions from individual PVC materials, adhesives and from complete structures.

    PubMed

    Järnström, H; Saarela, K; Kalliokoski, P; Pasanen, A-L

    2008-04-01

    Emission rates of volatile organic compounds (VOCs) and ammonia measured from six PVC materials and four adhesives in the laboratory were compared to the emission rates measured on site from complete structures. Significantly higher specific emission rates (SERs) were generally measured from the complete structures than from individual materials. There were large differences between different PVC materials in their permeability for VOCs originating from the underlying structure. Glycol ethers and esters from adhesives used in the installation contributed to the emissions from the PVC covered structure. Emissions of 2-ethylhexanol and TXIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate) were common. High ammonia SERs were measured from single adhesives but their contribution to the emissions from the complete structure did not appear as obvious as for VOCs. The results indicate that three factors affected the VOC emissions from the PVC flooring on a structure: 1) the permeability of the PVC product for VOCs, 2) the VOC emission from the adhesive used, and 3) the VOC emission from the backside of the PVC product. PMID:17997159

  16. Biological restorations using tooth fragments.

    PubMed

    Busato, A L; Loguercio, A D; Barbosa, A N; Sanseverino, M do C; Macedo, R P; Baldissera, R A

    1998-02-01

    A "biological" restoration technique using dental fragments and adhesive materials is described. These fragments were obtained from extracted human teeth which had been previously sterilized and stored in a tooth bank. The advantages are: the use of extracted teeth as restorative material, esthetics, and treatment cost. The positive sensation of having back the missing tooth was the most mentioned comment among patients. The disadvantages are: the difficulty of obtaining teeth with the needed characteristics, problems of making an indirect restoration, matching the original color, and the non-acceptance by some patients who consider it strange to have other people's teeth placed in their mouths. PMID:9823086

  17. The effect of delayed placement of composite and double application of single-bottle adhesives on microleakage of composite restorations.

    PubMed

    Shafiei, Fereshteh; Kiomarsi, Nazanin; Alavi, Ali Asghar

    2011-01-01

    This study evaluated the effect of delayed placement of composite and double application of adhesive on microleakage of two-step, total-etch (single-bottle) adhesives. Standard Class V cavities were prepared in 140 sound premolars and randomly assigned into 10 groups (n = 14). Excite, Optibond Solo Plus, and Adper Scotchbond Multi-Purpose (as a control) were used. After the first layer of single-bottle adhesive was photocured, the adhesive was reapplied and photocured in four of the groups. A microhybrid composite was applied in five of the groups immediately after the adhesive was photocured; in the other five groups, the composite was placed after a three-minute delay. After 24 hours of storage in distilled water and thermocycling, the samples were placed in 1% methylene blue. All samples then were sectioned longitudinally and evaluated for microleakage at the occlusal and gingival margins under a stereomicroscope at 20x magnification. Data were analyzed using nonparametric tests. Delayed placement of composite significantly increased leakage at the gingival margins when single-bottle adhesives were used (p < 0.05). Double application of the single-bottle adhesives significantly reduced leakage at the gingival margin when placement of the composite was delayed. There was no significant difference between single and double application when the composite was placed immediately (p < 0.05). PMID:21613038

  18. Proper restorative material selection, digital processes allow highly esthetic shade match combined with layered porcelain.

    PubMed

    Kahng, Luke S

    2014-03-01

    Today's digital technologies are affording dentists and laboratory technicians more control over material choices for creating restorations and fabricating dental prostheses. Digital processes can potentially enable technicians to create ideal marginal areas and account for the thickness and support of layering porcelain over substructures in the design process. In this case report of a restoration of a single central incisor, a number of issues are addressed that are central to using the newest digital technology. As demonstrated, shade selection is a crucial early step in any restorative case preparation. PMID:24773196

  19. Adhesion Between Volcanic Glass and Spacecraft Materials in an Airless Body Environment

    NASA Technical Reports Server (NTRS)

    Berkebile, Stephen; Street, Kenneth W., Jr.; Gaier, James R.

    2012-01-01

    The successful exploration of airless bodies, such as the Earth s moon, many smaller moons of the outer planets (including those of Mars) and asteroids, will depend on the development and implementation of effective dust mitigation strategies. The ultrahigh vacuum environment (UHV) on the surfaces of these bodies, coupled with constant ion and photon bombardment from the Sun and micrometeorite impacts (space weathering), makes dust adhesion to critical spacecraft systems a severe problem. As a result, the performance of thermal control surfaces, photovoltaics and mechanical systems can be seriously degraded even to the point of failure. The severe dust adhesion experienced in these environments is thought to be primarily due to two physical mechanisms, electrostatic attraction and high surface energies, but the dominant of these has yet to be determined. The experiments presented here aim to address which of these two mechanisms is dominant by quantifying the adhesion between common spacecraft materials (polycarbonate, FEP and PTFE Teflon, (DuPont) Ti-6-4) and a synthetic noritic volcanic glass, as a function of surface cleanliness and triboelectric charge transfer in a UHV environment. Adhesion force has been measured between pins of spacecraft materials and a plate of synthetic volcanic glass by determining the pull-off force with a torsion balance. Although no significant adhesion is observed directly as a result of high surface energies, the adhesion due to induced electrostatic charge is observed to increase with spacecraft material cleanliness, in some cases by over a factor of 10, although the increase is dependent on the particular material pair. The knowledge gained by these studies is envisioned to aid the development of new dust mitigation strategies and improve existing strategies by helping to identify and characterize mechanisms of glass to spacecraft adhesion for norite volcanic glass particles. Furthermore, the experience of the Apollo missions

  20. Antibacterial Effect and Physical-Mechanical Properties of Temporary Restorative Material Containing Antibacterial Agents

    PubMed Central

    Mushashe, Amanda Mahammad; Gonzaga, Carla Castiglia; Tomazinho, Paulo Henrique; da Cunha, Leonardo Fernandes; Leonardi, Denise Piotto; Pissaia, Janes Francio; Correr, Gisele Maria

    2015-01-01

    Introduction. For the maintenance of the aseptic chain created during the treatment the coronal sealing becomes paramount. Aim. Evaluating the antibacterial effect and the physical-mechanical properties of a temporary restorative material containing different antibacterial agents. Material and Methods. Two antibacterial agents (triclosan and chloramine T) were manually added to a temporary restorative material used as base (Coltosol). The antibacterial action of the material was analyzed using the agar diffusion method, in pure cultures of Escherichia coli (ATCC BAA-2336) and Staphylococcus aureus (ATCC 11632) and mixed culture of saliva collection. The microleakage rate was analyzed using bovine teeth, previously restored with the materials, and submitted to thermocycling, in a solution of 0.5% methylene blue, for a period of 24 hours. The physical and mechanical properties of the materials analyzed were setting time, water sorption, solubility, and compression strength. Results. No marginal leakage was observed for all groups. There was no statistical significant difference in antimicrobial activity, setting time, water sorption, solubility, and compression strength among the materials. Conclusion. The addition of antibacterial agents on a temporary restorative material did not optimize the antibacterial ability of the material and also did not change its physical-mechanical properties. PMID:27347539

  1. Laser equipment for investigation of light distribution in dental tissues and restorative materials

    NASA Astrophysics Data System (ADS)

    Grisimov, Vladimir N.; Smirmov, Alexander V.; Stafeev, Sergey C.

    1997-04-01

    The description of experimental set-up for investigation of light scattering in dental tissue and dental restorative material is presented. The set-up includes the light source (He-Ne laser), beam shaping light polarization control unit and registration device. The latter represents the computer interfaced CCD-camera. The experimental results of side light scattering in enamel/dentin and in double-layer porcelain are represented. The results of this research may be useful for aesthetic dental restorations.

  2. Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98--FDI World Dental Federation study design (Part I) and criteria for evaluation (Part II) of direct and indirect restorations including onlays and partial crowns.

    PubMed

    Hickel, Reinhard; Roulet, Jean-François; Bayne, Stephen; Heintze, Siegward D; Mjör, Ivar A; Peters, Mathilde; Rousson, Valentin; Randall, Ros; Schmalz, Gottfried; Tyas, Martin; Vanherle, Guido

    2007-01-01

    clinical trial designs, guidelines for design, randomization, number of subjects, characteristics of participants, clinical assessment, standards and calibration, categories for assessment, criteria for evaluation, and supplemental documentation. Part 2 of the review considers categories of assessment for esthetic evaluation, functional assessment, biological responses to restorative materials, and statistical analysis of results. The overall review represents a considerable effort to include a range of clinical research interests over the past years. As part of the recognition of the importance of these suggestions, the review is being published simultaneously in identical form in both the Journal of Adhesive Dentistry and Clinical Oral Investigations. Additionally, an extended abstract will be published in the International Dental Journal, giving a link to the web full version. This should help to introduce these considerations more quickly to the scientific community. PMID:18341239

  3. The bond strength of different tray adhesives on vinyl polysiloxane to two tray materials: an in vitro study.

    PubMed

    Ashwini, B L; Manjunath, S; Mathew, K Xavier

    2014-03-01

    There has been no established chemical bonding between custom tray resin and the elastomeric impression materials without the use of manufacturer's recommended specific tray adhesive. The present study was aimed to compare the bond strength of the manufacturer recommended tray adhesives with the universal tray adhesives using the medium body consistency vinyl polysiloxane (VPS) material and custom tray made of autopolymerising resin and visible light cure (VLC) resin. A total 90 cubicle specimens of autopolymerising resin and 90 specimens of VLC resin were tested for its tensile bond strength. Effectiveness of universal tray adhesive was compared with manufactured tray adhesive. Each of these specimens was then subjected to tensile load in hounsefield universal testing machine at a cross head speed of 5 mm/min and the results were compared and evaluated using one way analysis of variance and post hoc Tuckey's test. Analysis of bond strength revealed that the universal tray adhesive showed better strength and was statiscally significant when compared to the manufacture supplied tray adhesive. Comparison between both the groups, VLC resin showed better bond strength as compared to autopolymerizing resin. Universal tray adhesive had better tensile bond strength than the manufacturers recommended tray adhesive with the medium body viscosity VPS impression material for both autopolymerising and VLC tray resin. PMID:24604995

  4. Lunar building materials: Some considerations on the use of inorganic polymers. [adhesives, coatings, and binders

    NASA Technical Reports Server (NTRS)

    Lee, S. M.

    1979-01-01

    The use of inorganic polymer systems synthesized from the available lunar chemical elements, viz., silicon, aluminum, and oxygen to make adhesives, binders, and sealants needed in the fabrication of lunar building materials and the assembly of structures is considered. Inorganic polymer systems, their background, status, and shortcomings, and the use of network polymers as a possible approach to synthesis are examined as well as glassy metals for unusual structural strength, and the use of cold-mold materials as well as foam-sintered lunar silicates for lightweight shielding and structural building materials.

  5. Marginal leakage of visible light-cured glass ionomer restorative materials.

    PubMed

    Crim, G A

    1993-06-01

    This study examined the sealing of two visible light-cured glass ionomer restorative materials and a conventional glass ionomer. Class V cavity preparations were completed at the cementoenamel junction on the facial and lingual surfaces of extracted human molars. The cavity preparations were restored with either VariGlass VLC, GC Fuji II LC, or GC Fuji II glass ionomer cements. The restored teeth were thermocycled, immersed in fuchsin dye for 24 hours, sectioned, and evaluated with a measuring microscope. No microleakage occurred at the enamel/glass ionomer or dentin/glass ionomer cement interfaces of any samples, but the enamel adjacent to the VariGlass glass ionomer cement restorations exhibited crazing and staining. PMID:8320640

  6. Study on effects of partial ossicular replacement prostheses with different materials on hearing restoration.

    PubMed

    Yao, Wenjuan; Guo, Cuiping; Luo, Xuemei

    2013-02-01

    Numerical simulation method was used in this paper to study the effects of partial ossicular replacement prostheses (PORPs) with different materials on hearing restoration, from the biomechanical point of view. According to the CT scan imagery of the right ear from a normal human body, the CT data was digitalized and imported into PATRAN to establish a three dimension finite element model by self-compiling program, and then a frequency response analysis was made for the model. The calculated results were compared with experiment data to verify the correctness of the numerical model. Based on this, human numerical model of PORPs was established to make dynamic calculation of sound conduction and analyse the effects of PORPs with different materials on hearing restoration. The following conclusions are obtained : From the angle of dynamical behaviors in sound conduction process of human ear, in different frequency bands of the same sound pressure, PORPs with different materials have different effects on hearing restoration. A better sound transmission in low frequencies is obtained by PORPs with hydroxyapatite ceramics, stainless steel. In high frequencies, better sound transmission is gained by PORPs with porous polyethylene. In the 500-3,000 Hz range which is clinicians typically measure and pay attention to, better sound transmission is gained by PORPs with alumina ceramics, hydroxyapatite ceramics, EH composite materials and porous polyethylene. There are three materials which has an obvious potential to provide more hearing restoration than another between 500 and 3,000 Hz. The hearing restoration value of hydroxyapatite ceramics is 7.1 dB larger than that of stainless steel. The hearing restoration value of titanium is 4.9 dB larger than that of stainless steel. Hydroxyapatite ceramics has better effects on sound transmission than titanium and other materials. PMID:23109043

  7. Dual ion beam irradiation of polymeric materials for the modification of optical properties with improved adhesion

    NASA Astrophysics Data System (ADS)

    Park, Jae-Won; Lee, Eal H.; Lee, Jae-Sang; Lee, Byung-hoon; Kim, Min-kyu; Lee, Chan-Young; Kim, Hyung-jin; Choi, Byung-Ho

    2012-06-01

    Metallic (chromium) coating has often been applied on the surface of polymeric components, mainly to improve their appearance with a metallic luster and to protect from degradation under UV and visible light. However, the toxic nature of hexavalent chromium and delamination problems are an increasing concern in the plating industry. A similar metallic luster and the UV-visible light protection can be achieved by treating the surface of polymers by ion beams. However, a degradation by weathering including cracks, loss of glossiness, blistering, and eventual delamination have been problematic for ion beam processed polymers, particularly with a single ion beam irradiation. The main cause of adhesion failure is the abrupt change in material properties at the interface between coating and polymer or ion beam treated surface and the underlying untreated bulk polymer. In this work, therefore, a method is developed that improves adhesion by producing a graded interface by employing a dual ion beam processing. For demonstration purposes in this work, polycarbonate/acrylonitrile butadiene styrene blends were irradiated first with nitrogen ions followed by helium ions, achieving the desired metallic luster with improved adhesion. The experimental findings are explained in light of the stopping range of ions in materials and their interaction mechanisms with polymeric materials.

  8. Microgravity Experiments to Evaluate Electrostatic Forces in Controlling Cohesion and Adhesion of Granular Materials

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Weislogel, M.; Jacobson, T.

    1999-01-01

    The bulk behavior of dispersed, fluidized, or undispersed stationary granular systems cannot be fully understood in terms of adhesive/cohesive properties without understanding the role of electrostatic forces acting at the level of the grains themselves. When grains adhere to a surface, or come in contact with one another in a stationary bulk mass, it is difficult to measure the forces acting on the grains, and the forces themselves that induced the cohesion and adhesion are changed. Even if a single gain were to be scrutinized in the laboratory, it might be difficult, perhaps impossible, to define the distribution and character of surface charging and the three- dimensional relationship that charges (electrons, holes) have to one another. The hypothesis that we propose to test in microgravity (for dielectric materials) is that adhesion and cohesion of granular matter are mediated primarily by dipole forces that do not require the presence of a net charge; in fact, nominally electrically neutral materials should express adhesive and cohesive behavior when the neutrality results from a balance of positive and negative charge carriers. Moreover, the use of net charge alone as a measure of the electrical nature of grain-to-grain relationships within a granular mass may be misleading. We believe that the dipole forces arise from the presence of randomly-distributed positive and negative fixed charge carriers on grains that give rise to a resultant dipole moment. These dipole forces have long-range attraction. Random charges are created whenever there is triboelectrical activity of a granular mass, that is, whenever the grains experience contact/separation sequences or friction. Electrostatic forces are generally under-estimated for their role in causing agglomeration of dispersed grains in particulate clouds, or their role in affecting the internal frictional relationships in packed granular masses. We believe that electrostatic, in particular dipole-mediated processes

  9. Adhesive bonding and brazing of nanocrystalline diamond foil onto different substrate materials

    NASA Astrophysics Data System (ADS)

    Lodes, Matthias A.; Sailer, Stefan; Rosiwal, Stefan M.; Singer, Robert F.

    2013-10-01

    Diamond coatings are used in heavily stressed industrial applications to reduce friction and wear. Hot-filament chemical vapour deposition (HFCVD) is the favourable coating method, as it allows a coating of large surface areas with high homogeneity. Due to the high temperatures occurring in this CVD-process, the selection of substrate materials is limited. With the desire to coat light materials, steels and polymers a new approach has been developed. First, by using temperature-stable templates in the HFCVD and stripping off the diamond layer afterwards, a flexible, up to 150 μm thick and free standing nanocrystalline diamond foil (NCDF) can be produced. Afterwards, these NCDF can be applied on technical components through bonding and brazing, allowing any material as substrate. This two-step process offers the possibility to join a diamond layer on any desired surface. With a modified scratch test and Rockwell indentation testing the adhesion strength of NCDF on aluminium and steel is analysed. The results show that sufficient adhesion strength is reached both on steel and aluminium. The thermal stress in the substrates is very low and if failure occurs, cracks grow undercritically. Adhesion strength is even higher for the brazed samples, but here crack growth is critical, delaminating the diamond layer to some extent. In comparison to a sample directly coated with diamond, using a high-temperature CVD interlayer, the brazed as well as the adhesively bonded samples show very good performance, proving their competitiveness. A high support of the bonding layer could be identified as crucial, though in some cases a lower stiffness of the latter might be acceptable considering the possibility to completely avoid thermal stresses which occur during joining at higher temperatures.

  10. Influence of Full Veneer Restoration on Fracture Resistance of Three Different Core Materials: An Invitro Study

    PubMed Central

    Manoharan, P.S; Shekhawat, Kuldeep Singh; Deb, Saikat; Chidambaram, S.; Konchada, Jagadish; Venugopal, Nirupa; Vadivel, Harish

    2015-01-01

    Aims and Objectives One of the factor which affects the strength of the tooth restored with core material is the property of the material. In clinical situation all such restored teeth are protected by crowns. This study evaluated the strength of different core materials on a compromised tooth structure after restoration with a crown. Materials and Methods Seventy extracted intact human premolars were collected and mounted within a mould using auto-polymerizing resin. The teeth were divided in-to four groups - A, B, C and D. Each group contained 20 teeth except group A with 10 teeth. All the teeth were prepared for full veneer cast crown. Except for the teeth in group: A) extensive class-I cavities were prepared in the teeth of all the groups and restored with; B) composite resin, 3M EPSE Filtek P60; C) Silver reinforced glass ionomer, SHOFU Hi Dense XP and; (D) Resin reinforced glass ionomer, GC Gold Label light cure GIC. All the teeth were restored with cast-metal alloy and exposed to 1.2 million cycles of cyclic loading in a chewing simulator. Subsequently, the teeth that survived were loaded till fracture in the universal testing machine. Fracture loads and type of fractures were recorded. Results All the specimens survived cyclic loading. The mean fracture strength of the silver reinforced glass ionomer was greater with and without crown (p<0.001). Statistical analysis for the mean fracture load of each specimen showed significant difference between the groups. Conclusion Under the condition of this study, core materials when restored with artificial crown had a significant increase in fracture resistance. PMID:26501004

  11. Direct Tensile Strength and Characteristics of Dentin Restored with All-Ceramic, Resin-Composite, and Cast Metal Prostheses Cemented with Resin Adhesives

    PubMed Central

    Piemjai, Morakot; Nakabayashi, Nobuo

    2015-01-01

    A dentin-cement-prosthesis complex restored with either all-porcelain, cured resin-composite, or cast base metal alloy and cemented with either of the different resin cements was trimmed into a mini-dumbbell shape for tensile testing. The fractured surfaces and characterization of the dentin-cement interface of bonded specimens were investigated using a Scanning Electron Microscope. A significantly higher tensile strength of all-porcelain (12.5 ± 2.2 MPa) than that of cast metal (9.2 ± 3.5 MPa) restorations was revealed with cohesive failure in the cement and failure at the prosthesis-cement interface in Super-Bond C&B group. No significant difference in tensile strength was found among the types of restorations using the other three cements with adhesive failure on the dentin side and cohesive failure in the cured resin. SEM micrographs demonstrated the consistent hybridized dentin in Super-Bond C&B specimens that could resist degradation when immersed in hydrochloric acid followed by NaOCl solutions whereas a detached and degraded interfacial layer was found for the other cements. The results suggest that when complete hybridization of resin into dentin occurs tensile strength at the dentin-cement is higher than at the cement-prosthesis interfaces. The impermeable hybridized dentin can protect the underlying dentin and pulp from acid demineralization, even if detachment of the prosthesis has occurred. PMID:26539520

  12. Direct Tensile Strength and Characteristics of Dentin Restored with All-Ceramic, Resin-Composite, and Cast Metal Prostheses Cemented with Resin Adhesives.

    PubMed

    Piemjai, Morakot; Nakabayashi, Nobuo

    2015-01-01

    A dentin-cement-prosthesis complex restored with either all-porcelain, cured resin-composite, or cast base metal alloy and cemented with either of the different resin cements was trimmed into a mini-dumbbell shape for tensile testing. The fractured surfaces and characterization of the dentin-cement interface of bonded specimens were investigated using a Scanning Electron Microscope. A significantly higher tensile strength of all-porcelain (12.5 ± 2.2 MPa) than that of cast metal (9.2 ± 3.5 MPa) restorations was revealed with cohesive failure in the cement and failure at the prosthesis-cement interface in Super-Bond C&B group. No significant difference in tensile strength was found among the types of restorations using the other three cements with adhesive failure on the dentin side and cohesive failure in the cured resin. SEM micrographs demonstrated the consistent hybridized dentin in Super-Bond C&B specimens that could resist degradation when immersed in hydrochloric acid followed by NaOCl solutions whereas a detached and degraded interfacial layer was found for the other cements. The results suggest that when complete hybridization of resin into dentin occurs tensile strength at the dentin-cement is higher than at the cement-prosthesis interfaces. The impermeable hybridized dentin can protect the underlying dentin and pulp from acid demineralization, even if detachment of the prosthesis has occurred. PMID:26539520

  13. Short-term fluoride release from various aesthetic restorative materials.

    PubMed

    Yap, Adrian U J; Tham, S Y; Zhu, L Y; Lee, H K

    2002-01-01

    The short-term fluoride release of a giomer (Reactmer), a compomer (Dyract AP), a conventional glass ionomer cement (Fuji II Cap) and a resin-modified glass ionomer cement (Fuji II LC) was evaluated and compared. Specimen discs (6 +/-0.2 mm diameter and 1 +/- 0.2 mm thick) were prepared for each material using custom molds. Each disc was placed in 1 ml of deionized for 24 hours at 37 degrees C. After one day, the water was extracted and analyzed. The specimen discs were then re-immersed into another 1 ml of fresh deionized water. The procedure of removing and refilling the water was repeated for 28 days. Sample solutions taken during the first seven days and at days 14, 21 and 28 were introduced into a capillary electrophoresis system using field amplified sample injection (FASI) to determine fluoride release. Data was analyzed using factorial ANOVA/Scheffe's post-hoc test at significance level 0.05. An initial fluoride "burst" effect was observed with glass ionomers. Both compomer and giomer did not show an initial fluoride "burst" effect. With the exception of the compomer, fluoride release at day one was generally significantly greater than at the other time intervals. The glass ionomers released significantly more fluoride than the compomer and giomer at day one. Although fluoride release of the giomer was significantly greater than the other materials at day seven, it became significantly lower at day 28. PMID:12022457

  14. Effect of Soft Drinks and Fresh Fruit Juice on Surface Roughness of Commonly used Restorative Materials

    PubMed Central

    Satish, V; Prabhakar, AR; Namineni, Srinivas

    2015-01-01

    ABSTRACT In this in vitro study, the effects of a Cola drink, and fresh fruit juice (citrus) on the surface roughness on flowable composite and resin-modified glass ionomer cement (RMGIC) each was evaluated and compared. Using a brass mold 70 pellets each of flowable composite (Filtek™ Flow) and RMGIC tricure restorative material were prepared according to the manufacturer’s instructions. Two groups (groups I and II) were formed containing 30 pellets of each material. Remaining 10 pellets of each restorative material did form the control group [water (group III)]. Experimental group pellets were again divided into three subgroups (mild, moderate and severe) containing 10 pellets each and were kept in plastic containers with 30 ml Cola drink (group I) and fresh fruit juice (group II) respectively. Immersion regime was followed according to M aupome G et al. Baseline and final surface roughness (Ra) value for each pellet was evaluated using a profilometer. Statistical analysis was done with Wilcoxon’s signed rank test and analysis of variance (ANOVA) followed by Mann-Whitney test. Results showed that the erosive effect of both Cola drink and fresh fruit juice caused significant surface roughness on both flowable composite and RMGIC restorative materials in the mild, moderate and severe immersion regimes. How to cite this article: Maganur P, Satish V, Prabhakar AR, Namineni S. Effect of Soft Drinks and Fresh Fruit Juice on Surface Roughness of Commonly used Restorative Materials. Int J Clin Pediatr Dent 2015;8(1):1-5. PMID:26124573

  15. Effects of pulp capping materials on fracture resistance of Class II composite restorations

    PubMed Central

    Kucukyilmaz, Ebru; Yasa, Bilal; Akcay, Merve; Savas, Selcuk; Kavrik, Fevzi

    2015-01-01

    Objective: The aim of this study was to investigate the effect of cavity design and the type of pulp capping materials on the fracture resistance of Class II composite restorations. Materials and Methods: Sixty freshly extracted, sound molar teeth were selected for the study. A dovetail cavity on the mesio-occlusal and a slot cavity on disto-occlusal surfaces of each tooth were prepared, and the teeth were divided 4 groups which one of them as a control group. The pulp capping materials (TheraCal LC, Calcimol LC, Dycal) applied on pulpo-axial wall of each cavity, and the restoration was completed with composite resin. The teeth were subjected to a compressive load in a universal mechanical testing machine. The surfaces of the tooth and restoration were examined under a stereomicroscope. The data were analyzed using factorial analysis of variance and Tukey's test. Results: For pulp capping materials, the highest fracture load (931.15 ± 203.81 N) and the lowest fracture load (832.28 ± 245.75 N) were calculated for Control and Dycal group, respectively. However, there were no statistically significant differences among all groups (P > 0.05). The fracture load of the dovetail groups was significantly higher than those of the slot cavity groups (P < 0.05). Conclusion: Dovetail cavity design shows better fracture resistance in Class II composite restorations, independent of used or not used pulp capping materials. PMID:26038653

  16. Effect of Soft Drinks and Fresh Fruit Juice on Surface Roughness of Commonly used Restorative Materials.

    PubMed

    Maganur, Prabhadevi; Satish, V; Prabhakar, A R; Namineni, Srinivas

    2015-01-01

    In this in vitro study, the effects of a Cola drink, and fresh fruit juice (citrus) on the surface roughness on flowable composite and resin-modified glass ionomer cement (RMGIC) each was evaluated and compared. Using a brass mold 70 pellets each of flowable composite (Filtek™ Flow) and RMGIC tricure restorative material were prepared according to the manufacturer's instructions. Two groups (groups I and II) were formed containing 30 pellets of each material. Remaining 10 pellets of each restorative material did form the control group [water (group III)]. Experimental group pellets were again divided into three subgroups (mild, moderate and severe) containing 10 pellets each and were kept in plastic containers with 30 ml Cola drink (group I) and fresh fruit juice (group II) respectively. Immersion regime was followed according to M aupome G et al. Baseline and final surface roughness (Ra) value for each pellet was evaluated using a profilometer. Statistical analysis was done with Wilcoxon's signed rank test and analysis of variance (ANOVA) followed by Mann-Whitney test. Results showed that the erosive effect of both Cola drink and fresh fruit juice caused significant surface roughness on both flowable composite and RMGIC restorative materials in the mild, moderate and severe immersion regimes. How to cite this article: Maganur P, Satish V, Prabhakar AR, Namineni S. Effect of Soft Drinks and Fresh Fruit Juice on Surface Roughness of Commonly used Restorative Materials. Int J Clin Pediatr Dent 2015;8(1):1-5. PMID:26124573

  17. Cerec anterior crowns: restorative options with monolithic ceramic materials.

    PubMed

    Reich, Sven; Fiedlar, Kurt

    2013-01-01

    The aim of this article is to discuss the different types of monolithic ceramic crowns that can be placed on anterior teeth with existing shoulder preparations. Anterior crowns were indicated for the teeth 12 to 22 in the present case. The patient, a 65-year-old male, had received all-ceramic crowns 20 years earlier, which had started to develop cracks and palatal fractures over the last few years. The patient's teeth were prepared and four sets of crowns were fabricated using different monolithic ceramic materials: IPS e.max CAD, Cerec Blocs C In, VITABLOCS Real Life, and ENAMIC. Both shade characterization and crystallization firing were performed on the monolithic lithium disilicate glass ceramic crowns. The silicate ceramic crowns received glaze firing alone. The crowns made of hybrid ceramic (ENAMIC) were treated with a polymer sealant. PMID:24555406

  18. The 24-year clinical performance of porcelain laminate veneer restorations bonded with a two-liquid silane primer and a tri-n-butylborane-initiated adhesive resin.

    PubMed

    Nakamura, Mitsuo; Matsumura, Hideo

    2014-09-01

    This report describes the bonding technique and clinical course of porcelain laminate veneer restorations applied to discolored maxillary incisors and canines. The patient was an 18-year-old woman, and tooth reduction was limited to the enamel. Laminate veneer restorations were made with a feldspathic porcelain material (Cosmotech Porcelain). After try-in, enamel surfaces were etched with 65% phosphoric acid gel, and a tri-n-butylborane-initiated resin (Super-Bond C&B) was applied as a bonding agent. The inner surface of the restorations was etched with 5% hydrofluoric acid gel (HF Gel) and treated with a two-liquid silane primer (Porcelain Liner M), after which the Super-Bond resin was applied. Each restoration was seated with a dual-activated composite luting agent (Cosmotech Composite). After 24 years and 8 months, the restorations are functioning satisfactorily. The luting system and bonding technique described in this report are an option for seating laminate veneer restorations made of silica-based tooth-colored ceramics. PMID:25231150

  19. Cariostatic effect of fluoride-containing restorative materials associated with fluoride gels on root dentin

    PubMed Central

    BORGES, Fernanda Tavares; CAMPOS, Wagner Reis da Costa; MUNARI, Lais Sant'ana; MOREIRA, Allyson Nogueira; PAIVA, Saul Martins; MAGALHÃES, Claudia Silami

    2010-01-01

    Secondary caries is still the main cause of restoration replacement, especially on the root surface Objective This in vitro study evaluated the cariostatic effects of fluoride-containing restorative materials associated with fluoride gels, on root dentin. Materials and Methods A randomized complete block design was used to test the effects of the restorative systems, fluoride regimes and the interactions among them at different distances from restoration margins. Standardized cavities were prepared on 240 bovine root specimens and randomly assigned to 15 groups of treatments (n=16). Cavities were filled with the following restorative materials: Ketac-Fil (3M-ESPE); Vitremer (3M-ESPE); Dyract/Prime & Bond NT (Dentsply); Charisma/Gluma One Bond (Heraeus Kulzer) and the control, Z250/Single Bond (3M-ESPE). The specimens were subjected to a pH-cycling model designed to simulate highcaries activity. During the cycles, 1.23% acidulated phosphate fluoride, 2.0% neutral sodium fluoride or deionized/distilled water (control) was applied to the specimens for 4 min. The surface Knoop microhardness test was performed before (KHNi) and after (KHNf) the pH cycles at 100, 200 and 300 mm from the margins. Dentin microhardness loss was represented by the difference in initial and final values (KHNi - KHNf). Data were analyzed by Friedman's and Wilcoxon's tests, ANOVA and Tukey's test (α=5%). Results The interaction of restorative systems and topical treatments was not significant (p=0.102). Dentin microhardness loss was lowest closer to the restoration. Ketac-fil presented the highest cariostatic effect. Vitremer presented a moderate effect, while Dyract and Charisma did not differ from the control, Z250. The effects of neutral and acidulated fluoride gels were similar to each other and higher than the control. Conclusion Conventional and resin-modified glass ionomer cements as well as neutral and acidulated fluoride gels inhibit the progression of artificial caries adjacent to

  20. Radiopacity of different shades of resin-based restorative materials compared to human and bovine teeth.

    PubMed

    Pekkan, Gurel; Ozcan, Mutlu

    2012-01-01

    This study evaluated the radiopacity of different shades of resin-based restorative materials and compared the results to human and bovine dental hard tissues. Disk specimens 6 mm in diameter and 1 mm thick (N = 220, n = 10) were prepared from the following restorative materials: · eight shades of nanofilled composite (Aelite Aesthetic Enamel), · seven shades of nanohybrid composite (Grandio Universal), · six shades of photopolymerized polyacid modified compomer (Glasiosite), and · one shade of hybrid composite (X-tra fil U). Human canine dentin (n = 10), bovine enamel (n = 10), and an aluminum (Al) step wedge were used as references. The optical density values of each material were measured from radiographic images using a transmission densitometer. Al step wedge thickness and optical density values were plotted, and equivalent Al thickness (eq Al) values were determined for radiopacity measurements of each material. The data were analyzed using a non-parametric one-way ANOVA (Kruskal-Wallis), and multiple comparisons were made with a Student-Newman-Keuls post hoc test (a = 0.05). Different shades of resin-based restorative materials tested did not reveal statistically significant differences within each material group (p > 0.05). Radiopacity values of the resin-based restorative materials investigated varied depending on their types; however, within different shades of one material type, radiopacity values were comparable. Every shade of nanocomposite material other than Aelite Aesthetic Enamel Incisal LT Gray showed comparable radiopacity to human dentin. Other materials tested demonstrated higher radiopacity compared to human dentin and bovine enamel. PMID:22782058

  1. Effect of restorative materials and in vitro carious challenge on amalgam margin quality.

    PubMed

    Grossman, E S; Matejka, J M

    1996-09-01

    The surface margin of a restoration is where the restored tooth is subjected to aggressive oral attack. Any resistance to this attack will have favorable consequences on the clinical performance and longevity of the restoration. In this study, Black's class I classic cavity preparations were completed in 120 extracted intact human premolars that were restored with one of two silver amalgams, six different base conditions, and with or without cavity varnish, resulting in 20 different restoration combinations. The cavities were aged for 3 months and 1 year in 1% NaCl at 20 degrees C. A resin cast impression was made of the restoration margin for each specimen. Thereafter 80 restored teeth were subjected to an in vitro bacterial challenge for 36 days. The other 40 specimens were placed in an acidified (pH = 4.0) broth for the same length of time. A second cast impression was then made of the margin of each specimen. The casts were examined with a scanning electron microscope and the widest gap of the margin opening and the length of margin showing a discrepancy were measured. Specimens were ranked first on the basis of the gap size and then on percent of margin discrepancy length. Results were evaluated with one-way ANOVA and Turkey's Student range test with a critical level of statistical significance (p < 0.05). Base type significantly affected aged margin quality. Cariogenic challenge caused a significant breakdown of the amalgam margin although the type of challenge was not significant. A shorter aging time, varnish, and high copper amalgam exacerbated the breakdown. Margin breakdown can be reduced by judicious selection of restoration material combinations. PMID:8887794

  2. CAD/CAM monolithic restorations and full-mouth adhesive rehabilitation to restore a patient with a past history of bulimia: the modified three-step technique.

    PubMed

    Vailati, Francesca; Carciofo, Sylvain

    2016-01-01

    Due to an increasing awareness about dental erosion, many clinicians would like to propose treatments even at the initial stages of the disease. However, when the loss of tooth structure is visible only to the professional eye, and it has not affected the esthetics of the smile, affected patients do not usually accept a full-mouth rehabilitation. Reducing the cost of the therapy, simplifying the clinical steps, and proposing noninvasive adhesive techniques may promote patient acceptance. In this article, the treatment of an ex-bulimic patient is illustrated. A modified approach of the three-step technique was followed. The patient completed the therapy in five short visits, including the initial one. No tooth preparation was required, no anesthesia was delivered, and the overall (clinical and laboratory) costs were kept low. At the end of the treatment, the patient was very satisfied from a biologic and functional point of view. PMID:26835523

  3. Microgravity Experiments to Evaluate Electrostatic Forces in Controlling Cohesion and Adhesion of Granular Materials

    NASA Technical Reports Server (NTRS)

    Marshall, J.; Weislogel, M.; Jacobson, T.

    1999-01-01

    The bulk behavior of dispersed, fluidized, or undispersed stationary granular systems cannot be fully understood in terms of adhesive/cohesive properties without understanding the role of electrostatic forces acting at the level of the grains themselves. When grains adhere to a surface, or come in contact with one another in a stationary bulk mass, it is difficult to measure the forces acting on the grains, and the forces themselves that induced the cohesion and adhesion are changed. Even if a single grain were to be scrutinized in the laboratory, it might be difficult, perhaps impossible, to define the distribution and character of surface charging and the three-dimensional relationship that charges (electrons, holes) have to one another. The hypothesis that we propose to test in microgravity (for dielectric materials) is that adhesion and cohesion of granular matter are mediated primarily by dipole forces that do not require the presence of a net charge; in fact, nominally electrically neutral materials should express adhesive and cohesive behavior when the neutrality results from a balance of positive and negative charge carriers. Moreover, the use of net charge alone as a measure of the electrical nature of grain-to-grain relationships within a granular mass may be misleading. We believe that the dipole forces arise from the presence of randomly-distributed positive and negative fixed charge carriers on grains that give rise to a resultant dipole moment. These dipole forces have long-range attraction. Random charges are created whenever there is triboelectrical activity of a granular mass, that is, whenever the grains experience contact/separation sequences or friction.

  4. Investigation of the electrical properties of some dental composite restorative materials before and after laser exposure.

    PubMed

    ElKestawy, M A; Saafan, S A; Shehata, M M; Saafan, A M

    2006-10-01

    Some electrical properties, such as piezoelectricity, ac conductivity, dielectric constant and loss tangent of nine commercial types of dental composite restorative materials, have been investigated before and after laser exposure for 3s to study the effect of a probable laser exposure during some surgeries on the electrical properties of these materials. No piezoelectric effect has been found in these materials before and after laser exposure. The materials were found to be good insulators (very poorly conducting materials). The temperature and frequency dependence of ac conductivity, dielectric constant and loss tangent have not shown significant changes in values after laser exposure. PMID:16387356

  5. Effect of Naturally Acidic Agents on Microhardness and Surface Micromorphology of Restorative Materials

    PubMed Central

    Hengtrakool, Chanothai; Kukiattrakoon, Boonlert; Kedjarune-Leggat, Ureporn

    2011-01-01

    Objectives: This study investigated the titratable acidity and erosive potential of acidic agents on the microhardness and surface micromorphology of four restorative materials. Methods: Forty-seven discs of each restorative material; metal-reinforced glass ionomer cement (Ketac-S), resin-modified glass ionomer cement (Fuji II LC), resin composite (Filtek Z250) and amalgam (Valiant-Ph.D.), 12 mm in diameter and 2.5 mm in thickness, were divided into four groups (5 discs/group). Specimens were then immersed for 7 days into four storage media; deionized water (control), citrate buffer solution, green mango juice and pineapple juice. Microhardness testing before and after immersions was performed. Micromorphological changes were evaluated under a scanning electron microscope (SEM). Statistical significance among each group was analyzed using two-way repeated ANOVA and Tukey’s tests. Results: The Fuji II LC and the Ketac-S showed the highest reduction in microhardness (P<.05). The Valiant-Ph.D. and the Filtek Z250 showed some minor changes over the period of 7 days. The mango juice produced the greatest degradation effect (P<.05). Conclusions: This study suggested that for restorations in patients who have tooth surface loss, materials selected should be considered. In terms of materials evaluated, amalgam and resin composite are the most suitable for restorations. PMID:21311608

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

    PubMed

    von Fraunhofer, J A; Kelley, J I; DePaola, L G; Meiller, T F

    2006-01-01

    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. PMID:17134077

  7. Longevity of Posterior Composite Restorations

    PubMed Central

    Opdam, N.J.M.; van de Sande, F.H.; Bronkhorst, E.; Cenci, M.S.; Bottenberg, P.; Pallesen, U.; Gaengler, P.; Lindberg, A.; Huysmans, M.C.D.N.J.M.; van Dijken, J.W.

    2014-01-01

    The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years’ follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces. PMID:25048250

  8. A new classification system for all-ceramic and ceramic-like restorative materials.

    PubMed

    Gracis, Stefano; Thompson, Van P; Ferencz, Jonathan L; Silva, Nelson R F A; Bonfante, Estevam A

    2015-01-01

    Classification systems for all-ceramic materials are useful for communication and educational purposes and warrant continuous revisions and updates to incorporate new materials. This article proposes a classification system for ceramic and ceramic-like restorative materials in an attempt to systematize and include a new class of materials. This new classification system categorizes ceramic restorative materials into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics. Subfamilies are described in each group along with their composition, allowing for newly developed materials to be placed into the already existing main families. The criteria used to differentiate ceramic materials are based on the phase or phases present in their chemical composition. Thus, an all-ceramic material is classified according to whether a glass-matrix phase is present (glass-matrix ceramics) or absent (polycrystalline ceramics) or whether the material contains an organic matrix highly filled with ceramic particles (resin-matrix ceramics). Also presented are the manufacturers' clinical indications for the different materials and an overview of the different fabrication methods and whether they are used as framework materials or monolithic solutions. Current developments in ceramic materials not yet available to the dental market are discussed. PMID:25965634

  9. Effect of material properties of composite restoration on the strength of the restoration-dentine interface due to polymerization shrinkage, thermal and occlusal loading.

    PubMed

    Borkowski, Krzysztof; Kotousov, Andrei; Kahler, Bill

    2007-07-01

    The purpose of this investigation was to adopt an analytical approach to analyse stresses at the restoration-dentine interface caused by polymerization shrinkage, occlusal and thermal loading with the primary focus on evaluating the effect of the material properties of the composite restoration on the strength of the interface. Some essential simplifications were employed to derive an explicit analytical solution. The results confirm previous findings that interfacial stresses due to polymerization shrinkage are increased with the higher modulus of elasticity of the restoration, while Poisson's ratio of the restorative material has a very small influence on these stresses. Occlusal loading resulted in much lower interfacial stresses when compared to shrinkage and thermal loads. The obtained results were in a good agreement with other numerical and clinical studies. From the modelling analysis it was found that the majority of commercially available composite restorative materials are expected to create significant interfacial stresses when subjected to cold temperatures. In addition, it was shown that there is a considerable potential for interfacial stresses to be minimised by an appropriate selection of thermo-mechanical properties of the restorative material especially with the new finding on the negative temperature variation effect. PMID:17000129

  10. Enhanced cell adhesion to silicone implant material through plasma surface modification.

    PubMed

    Hauser, J; Zietlow, J; Köller, M; Esenwein, S A; Halfmann, H; Awakowicz, P; Steinau, H U

    2009-12-01

    Silicone implant material is widely used in the field of plastic surgery. Despite its benefits the lack of biocompatibility this material still represents a major problem. Due to the surface characteristics of silicone, protein adsorption and cell adhesion on this polymeric material is rather low. The aim of this study was to create a stable collagen I surface coating on silicone implants via glow-discharge plasma treatment in order to enhance cell affinity and biocompatibility of the material. Non-plasma treated, collagen coated and conventional silicone samples (non-plasma treated, non-coated) served as controls. After plasma treatment the change of surface free energy was evaluated by drop-shape analysis. The quality of the collagen coating was analysed by electron microscopy and Time-Of-Flight Secondary Ion Mass Spectrometry. For biocompatibility tests mouse fibroblasts 3T3 were cultivated on the different silicone surfaces and stained with calcein-AM and propidium iodine to evaluate cell viability and adherence. Analysis of the different surfaces revealed a significant increase in surface free energy after plasma pre-treatment. As a consequence, collagen coating could only be achieved on the plasma activated silicone samples. The in vitro tests showed that the collagen coating led to a significant increase in cell adhesion and cell viability. PMID:19641852

  11. RESTORING A DAMAGED 16-YEAR -OLD INSULATING POLYMER CONCRETE DIKE OVERLAY: REPAIR MATERIALS AND TECHNOLOGIES.

    SciTech Connect

    SUGAMA,T.

    2007-01-01

    The objective of this program was to design and formulate organic polymer-based material systems suitable for repairing and restoring the overlay panels of insulating lightweight polymer concrete (ILPC) from the concrete floor and slope wall of a dike at KeySpan liquefied natural gas (LNG) facility in Greenpoint, Brooklyn, NY, just over sixteen years ago. It also included undertaking a small-scale field demonstration to ensure that the commercial repairing technologies were applicable to the designed and formulated materials.

  12. Risk assessment derived from migrants identified in several adhesives commonly used in food contact materials.

    PubMed

    Canellas, E; Vera, P; Nerín, C

    2015-01-01

    Adhesives are used to manufacture multilayer materials, where their components pass through the layers and migrate to the food. Nine different adhesives (acrylic, vinyl and hotmelt) and their migration in 21 laminates for future use as market samples have been evaluated and risk assessment has been carried out. A total of 75 volatiles and non volatile compounds were identified by gas chromatography-mass spectrometry and ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. Most of the compounds migrated below their specific migration limit (SML), lowest observed adverse effect level (LOAEL), no observed adverse effect level (NOAEL) and values recommended by Cramer. Six compounds classified as high toxicity class III according to Cramer classification, migrated over their SML and exposure values recommended by Cramer, when they were applied in the full area of the packaging. Nevertheless, these adhesives fulfill the threshold in the real application as they are applied in a small area of the packaging. PMID:25445514

  13. An exploration of plastic deformation dependence of cell viability and adhesion in metallic implant materials.

    PubMed

    Uzer, B; Toker, S M; Cingoz, A; Bagci-Onder, T; Gerstein, G; Maier, H J; Canadinc, D

    2016-07-01

    The relationship between cell viability and adhesion behavior, and micro-deformation mechanisms was investigated on austenitic 316L stainless steel samples, which were subjected to different amounts of plastic strains (5%, 15%, 25%, 35% and 60%) to promote a variety in the slip and twin activities in the microstructure. Confocal laser scanning microscopy (CLSM) and field emission scanning electron microscopy (FESEM) revealed that cells most favored the samples with the largest plastic deformation, such that they spread more and formed significant filopodial extensions. Specifically, brain tumor cells seeded on the 35% deformed samples exhibited the best adhesion performance, where a significant slip activity was prevalent, accompanied by considerable slip-twin interactions. Furthermore, maximum viability was exhibited by the cells seeded on the 60% deformed samples, which were particularly designed in a specific geometry that could endure greater strain values. Overall, the current findings open a new venue for the production of metallic implants with enhanced biocompatibility, such that the adhesion and viability of the cells surrounding an implant can be optimized by tailoring the surface relief of the material, which is dictated by the micro-deformation mechanism activities facilitated by plastic deformation imposed by machining. PMID:26807771

  14. Evaluation of the Flexural Strength of Interim Restorative Materials in Fixed Prosthodontics

    PubMed Central

    Mehrpour, Hanieh; Farjood, Ehsan; Giti, Rashin; Barfi Ghasrdashti, Alireza; Heidari, Hossein

    2016-01-01

    Statement of the Problem Mechanical properties of interim restorations are considered as important factors specially when selecting materials for long-term application or for patients with para-functional habits. Flexural strength is one of the most important components of these restorations. Purpose The purpose of this study was to compare the flexural strength of five interim restorative materials. Materials and Method Fifty identical samples sized 25×2×2-mm were made from five interim materials (TempSpan; Protemp 4, Unifast III, Trim, and Revotek LC) according to ADA specification #27. The specimens were stored in artificial saliva for 2 weeks and then thermocycled for 2500 cycles (5-55˚C). A standard three-point bending test was conducted on the specimens with a universal testing machine at a crosshead speed of 0.75mm/min. Data were analyzed by using one-way ANOVA and Tamhane’s post-hoc tests to measure the flexural strength of temporary materials. Results One of the bis-acryl resins (TempSpan) showed the highest, and the light polymerized resin (Revotek LC) showed the lowest flexural strength. The mean values of flexural strength (MPa) for the examined materials were as follow: TempSpan=120.00, Protemp 4=113.00, Unifast III=64.20, Trim= 63.73 and Revotek LC=47.16. There were significant differences between all materials except Trim and Unifast III which did not show any statistical significant difference. Conclusion Bis-acryl resins were statistically superior to traditional methacrylate and light-cured resins. Therefore, application of bis-acryl resins should be deliberated in patients with heavy occlusion and in cases that need long-term use of interim restorations. PMID:27602395

  15. Considerations regarding the optical properties of the composite resin restorative materials.

    PubMed

    Manolea, H; Râcă, R; Coleş, Evantia; Preotu, Gabriela; Mărăşescu, P

    2011-07-01

    The purpose of this study has been to investigate the effects of certain substances frequently used in alimentation on the color stability of the composite resin restorative materials. The research hypothesis was that color stability of the composite resin is affected by the type of composite material used and by the polishing procedure. 14 samples of 5X15X2mm have been prepared from seven universal light curing restorative composite resins. The materials have manipulated and cured using LA 500 Blue Light lamp. A first color determination was done before the introduction of the samples in the dyeing agent with the help of an Easy Shade device. The samples have been splited into two lots each with seven samples. The samples from the first lot have been sectioned into three equal segments. The samples from the second lot have also been sectioned into three equal segments, and in addition to the previous group, their exterior surfaces were processed with a diamond burr. For each type of composite we have introduced a sample in one of the three chosen dyes: red alimentary colorant, coffee and red wine. The color of the samples has been determined again using the Vita Easy Shade device. From clinical point of view the results of this study shows that there are three important factors that matter when we talk about durable aesthetic results: the type of composite resin used for the restoration, the finishing and polishing procedures and the pacients' alimentation habits. The composite resins with a good representation of the anorganic structure are easier to be polished, therefore they have only slight color modifications. Using plastic matrixes for shaping the exterior surface of the restoration is the best solution for obtaining a very smooth surface. The most significant color modifications have been done by the red wine. Coffee and to a smaller extent the red alimentary colorant have modified the color of the restoration material in a smaller degree. PMID:24778835

  16. Effects of different types of adhesive systems on the microleakage of compomer restorations in Class V cavities prepared by Er,Cr:YSGG laser in primary teeth.

    PubMed

    Baygin, Ozgul; Korkmaz, Fatih Mehmet; Arslan, Ipek

    2012-01-01

    The aim of this in vitro study was to evaluate the effects of different types of adhesive systems on the microleakage of compomer restorations in Class V cavities prepared by erbium, chromium: yttrium scandium gallium garnet (Er,Cr:YSGG) laser. There were five test groups according to the type of adhesive applied to the cavities: Adper Single Bond 2 (Group 1), Scotchbond Multi-Purpose Plus (Group 2), Xeno III (Group 3), Clearfil Protect Bond (Group 4), Prime&Bond NT (Group 5). Dye penetration was evaluated under a stereomicroscope, and data were statistically analyzed by Kruskal-Wallis and Wilcoxon Signed Ranks tests. Gingival margins showed significantly higher microleakage than occlusal margins in all the test groups (p<0.05). Groups 1 and 2 showed significantly less microleakage than Group 5 (p<0.05), and there were no statistically significant differences among Groups 3, 4, and 5 (p>0.05). None of the dentin bonding agents eliminated microleakage completely, and higher microleakage scores were observed along the gingival margin than the occlusal margin. PMID:22447053

  17. Priorities for future innovation, research, and advocacy in dental restorative materials.

    PubMed

    Watson, T; Fox, C H; Rekow, E D

    2013-11-01

    Innovations in materials science, both within and outside of dentistry, open opportunities for the development of exciting direct restorative materials. From rich dialog among experts from dental and non-dental academic institutions and industry, as well as those from policy, research funding, and professional organizations, we learned that capitalizing on these opportunities is multifactorial and far from straightforward. Beginning from the point when a restoration is needed, what materials, delivery systems, and skills are needed to best serve the most people throughout the world's widely varied economic and infrastructure systems? New research is a critical element in progress. Effective advocacy can influence funding and drives change in practice and policy. Here we articulate both research and advocacy priorities, with the intention of focusing the energy and expertise of our best scientists on making a difference, bringing new innovations to improve oral health. PMID:24129817

  18. Translucency of human teeth and dental restorative materials and its clinical relevance

    NASA Astrophysics Data System (ADS)

    Lee, Yong-Keun

    2015-04-01

    The purpose was to review the translucency of human teeth and related dental materials that should be considered for the development of esthetic restorative materials. Translucency is the relative amount of light transmission or diffuse reflection from a substrate surface through a turbid medium. Translucency influences the masking ability, color blending effect, and the degree of light curing through these materials. Regarding the translucency indices, transmission coefficient, translucency parameter, and contrast ratio have been used, and correlations among these indices were confirmed. Translucency of human enamel and dentine increases in direct proportion to the wavelength of incident light in the visible light range. As for the translucency changes by aging, limited differences were reported in human dentine, while those for enamel proved to increase. There have been studies for the adjustment of translucency in dental esthetic restorative materials; the size and amount of filler and the kind of resin matrix were modified in resin composites, and the kind of ingredient and the degree of crystallization were modified in ceramics. Based on the translucency properties of human enamel and dentine, those of replacing restorative materials should be optimized for successful esthetic rehabilitation. Biomimetic simulation of the natural tooth microstructure might be a promising method.

  19. Coronal microleakage with five different temporary restorative materials following walking bleach technique: An ex-vivo study

    PubMed Central

    Srikumar, G. P. V.; Varma, K. Ravi; Shetty, K. Harish; Kumar, Pramod

    2012-01-01

    Context: Walking bleach technique uses 30% hydrogen peroxide and sodium perborate, and this paste mixture causes loosening of the coronal temporary restorative materials and thus decreasing its clinical effectiveness and causing irritation to the patients oral tissues. In the present study, sealing ability of hygroscopic coronal temporary restorative materials were compared with the other commonly used temporary restorative materials. Aim: To evaluate the effects of walking bleach material on the marginal sealing ability and coronal microleakage of the hydrophilic temporary restorative materials with that of the other commonly used temporary restorative materials in endodontic practice. Materials and Methods: Seventy-five extracted human maxillary central incisor teeth were prepared chemo-mechanically and obturated with gutta-percha in lateral condensation technique. Surface of each tooth was double coated with cyanoacrylate glue. All the teeth were randomly divided in to five groups. Out of 15 teeth in each group, 10 teeth served as experimental specimens, in which bleaching agent was placed in the pulp chamber and 5 teeth served as control, in which no bleaching agent was placed. The access cavities were restored with temporary restorative materials being tested per each group respectively. The specimens were then immersed in 1% India ink dye and subjected to thermo cycling for 7 days. All the teeth were longitudinally sectioned and observed with stereomicroscope and were graded according to the depth of linear dye penetration. Statistical Analysis Used: Mann-Whitney U test and Kruskal-Wallis test. Results: Hydrophilic temporary restorative materials Cavit G and Coltosol F have shown minimal coronal dye leakage with better sealing ability when exposed to walking bleach paste mixture in the dye penetration tests compared to other commonly used temporary restorative materials. Conclusion: Marginal sealing ability of Cavit G and Coltosol F were not influenced by the

  20. Glass-ionomer Cements in Restorative Dentistry: A Critical Appraisal.

    PubMed

    Almuhaiza, Mohammed

    2016-01-01

    Glass-ionomer cements (GICs) are mainstream restorative materials that are bioactive and have a wide range of uses, such as lining, bonding, sealing, luting or restoring a tooth. Although the major characteristics of GICs for the wider applications in dentistry are adhesion to tooth structure, fluoride releasing capacity and tooth-colored restorations, the sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They have undergone remarkable changes in their composition, such as the addition of metallic ions or resin components to their composition, which contributed to improve their physical properties and diversified their use as a restorative material of great clinical applicability. The light-cured polymer reinforced materials appear to have substantial benefits, while retaining the advantages of fluoride release and adhesion. Further research should be directed towards improving the properties, such as strength and esthetics without altering its inherent qualities, such as adhesion and fluoride releasing capabilities. PMID:27340169

  1. Recombinant mussel adhesive protein fp-5 (MAP fp-5) as a bulk bioadhesive and surface coating material.

    PubMed

    Choi, Yoo Seong; Kang, Dong Gyun; Lim, Seonghye; Yang, Yun Jung; Kim, Chang Sup; Cha, Hyung Joon

    2011-08-01

    Mussel adhesive proteins (MAPs) attach to all types of inorganic and organic surfaces, even in wet environments. MAP of type 5 (fp-5), in particular, has been considered as a key adhesive material. However, the low availability of fp-5 has hampered its biochemical characterization and practical applications. Here, soluble recombinant fp-5 is mass-produced in Escherichia coli. Tyrosinase-modified recombinant fp-5 showed ∼1.11 MPa adhesive shear strength, which is the first report of a bulk-scale adhesive force measurement for purified recombinant of natural MAP type. Surface coatings were also performed through simple dip-coating of various objects. In addition, complex coacervate using recombinant fp-5 and hyaluronic acid was prepared as an efficient adhesive formulation, which greatly improved the bulk adhesive strength. Collectively, it is expected that this work will enhance basic understanding of mussel adhesion and that recombinant fp-5 can be successfully used as a realistic bulk-scale bioadhesive and an efficient surface coating material. PMID:21770718

  2. Adhesion, growth and differentiation of osteoblasts on surface-modified materials developed for bone implants.

    PubMed

    Vandrovcová, M; Bačáková, L

    2011-01-01

    This review briefly outlines the history and possibilities of bone reconstruction using various types of artificial materials, which allow interaction with cells only on the surface of the implant or enable ingrowth of cells inside the material. Information is also provided on the most important properties of bone cells taking part in bone tissue development, and on diseases and regeneration. The most common cell types used for testing cell-material interaction in vitro are listed, and the most commonly used approaches to this testing are also mentioned. A considerable part of this review is dedicated to the physical and chemical properties of the material surface, which are decisive for the cell-material interaction, and also to modifications to the surface of the material aimed at integrating it better with the surrounding bone tissue. Special attention is paid to the effects of nanoscale and microscale surface roughness on cell behaviour, to material surface patterning, which allows regionally-selective adhesion and growth of cells, and also to the surface chemistry. In addition, coating the materials with bioactive layers is examined, particularly those created by deposition of fullerenes, hybrid metal-fullerene composites, carbon nanotubes, nanocrystalline diamond films, diamond-like carbon, and nanocomposite hydrocarbon plasma polymer films enriched with metals. PMID:21401307

  3. Fracture resistance of endodontically treated teeth restored with ceramic inlays and different base materials.

    PubMed

    Saridag, Serkan; Sari, Tugrul; Ozyesil, Atilla Gokhan; Ari Aydinbelge, Hale

    2015-01-01

    This study evaluated the fracture resistance of endodontically treated teeth restored with different base materials and mesioocclusal-distal (MOD) ceramic inlays. Fifty mandibular molars were assigned into five groups (n=10 per group). Group1 (control) comprised intact molar teeth without any treatment. Teeth in other groups were subjected to root canal treatment and restored with MOD ceramic inlays on different base materials. In Group 2, base material was zinc phosphate cement; Group 3's was glass ionomer cement; Group 4's was composite resin, and Group 5's was composite resin reinforced with fiber. Finally, a continuous occlusal load was applied until fracture occurred. Mean fracture resistance of Group 1 (3,027 N) was significantly higher than the other groups (890, 1,070, 1,670, 1,226 N respectively). Fracture resistance of Group 4 was statistically comparable with Group 5 and significantly higher than Groups 2 and 3 (p<0.05; Tukey's HSD). Use of different base materials under ceramic inlay restorations could affect the fracture resistance of endodontically treated teeth. PMID:25740162

  4. Cytogenetic genotoxic investigation in peripheral blood lymphocytes of subjects with dental composite restorative filling materials.

    PubMed

    Pettini, F; Savino, M; Corsalini, M; Cantore, S; Ballini, A

    2015-01-01

    Dental composite resins are biomaterials commonly used to aesthetically restore the structure and function of teeth impaired by caries, erosion, or fracture. Residual monomers released from resin restorations as a result of incomplete polymerization processes interact with living oral tissues. The objective of this study was to evaluate the genotoxicity of a common dental composite material (Enamel Plus-HFO), in subjects with average 13 filled teeth with the same material, compared to a control group (subjects having neither amalgam nor composite resin fillings). Genotoxicity assessment of composite materials was carried out in vitro in human peripheral blood leukocytes using sister-chromatid exchange (SCE) and chromosomal aberrations (CA) cytogenetic tests. The results of correlation and multiple regression analyses confirmed the absence of a relationship between SCE/cell, high frequency of SCE(HFC) or CA frequencies and exposure to dental composite materials. These results indicate that composite resins used for dental restorations differ extensively in vivo in their cytotoxic and genotoxic potential and in their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair. PMID:25864763

  5. The effect of different drinks on the color stability of different restorative materials after one month

    PubMed Central

    Tuncer, Safa; Demirci, Mustafa; Serim, Merve Efe; Baydemir, Canan

    2015-01-01

    Objectives The aim of this study was to evaluate the effect of three different drinks on the color parameters of four different restorative materials. Materials and Methods Three different composites (Filtek Ultimate Universal Restorative, Filtek Ultimate Flowable, and Filtek Silorane, 3M ESPE) and a polyacid-modified composite resin material (Dyract XP, Dentsply DeTrey GmbH) were evaluated. Eighty-four disc-shaped specimens of 8 mm in diameter and 2 mm in thickness were prepared (n = 21 each). Color coordinates (L*a*b*, ΔL*, Δa*, Δb*, and ΔE*) were measured using a VİTA Easyshade Compact (VİTA Zahnfabrik) after 24 hr of storage (baseline) and after 30 day of storage in three different beverages of black tea, Coca cola, or water (control) (n = 7). In each beverage, the specimens were stored three times a day, one hr each, for 30 day. The color changes (ΔE) were calculated and were analyzed by Kruskal-Wallis and Dunn multiple comparison test. Results The color difference (ΔE*) of the resin materials ranged between 1.31 and 15.28 after 30 day of immersion in the staining solutions. Dyract XP in Coca cola (15.28 ± 2.61) and black tea (12.22 ± 2.73) showed the highest mean ΔE* value after 30 day, followed by Filtek Ultimate Universal Restorative (5.99 ± 1.25) and Filtek Ultimate Flowable (4.71 ± 1.40) in black tea (p < 0.05). Conclusions The compomers displayed unacceptable color changes at the end of 30 day in all beverages. Among resin composites, the silorane based composite exhibited relatively good color stability than the others. Filtek Ultimate Universal Restorative and Filtek Flowable showed similar color changes in all beverages. PMID:26587410

  6. Multi-material laser densification (MMLD) of dental restorations: Process optimization and properties evaluation

    NASA Astrophysics Data System (ADS)

    Li, Xiaoxuan

    This Ph.D. thesis proposes to investigate the feasibility of laser-assisted dental restoration and to develop a fundamental understanding of the interaction between laser beam and dental materials. Traditional dental restorations are produced by the porcelain-fused-to-metal (PFM) process, in which a dental restoration is cast from a metallic alloy and then coated with dental porcelains by multiple furnace-firing processes. PFM method is labor-intensive and hence very expensive. In order to fabricate dental restoration units faster and more cost-effectively, the Solid Freeform Fabrication (SFF) technique has been employed in this study. In particular, a Multi-Material Laser Densification (MMLD) process has been investigated for its potential to fabricate artificial teeth automatically from 3-D computer dental tooth files. Based on the principle of SFF, the MMLD process utilizes a micro-extruder system to deliver commercial dental alloy and porcelain slurry in a computer-controlled pattern line by line and layer by layer. Instead of firing the artificial tooth/teeth in a furnace, the extruded dental materials are laser scanned to convert the loose powder to a fully dense body. Different laser densification parameters including the densification temperature, laser output power, laser beam size, line dimension, ratio of the beam size to line width, beam scanning rate, processing atmosphere and pressure, dental powder state (powder bed or slurry), powder particle size, etc. have been used to evaluate their effects on the microstructures and properties of the laser densified dental body, and hence to optimize MMLD conditions. Furthermore, laser-scanning induced phase transformations in dental porcelains have been studied because the transformations have great impact on coefficient of thermal expansion (CTE) of dental porcelains, which should match that of dental alloy substrate. Since a single dental material line delivered by the MMLD system functions as a "construction

  7. An evaluation of complementary approaches to elucidate fundamental interfacial phenomena driving adhesion of energetic materials

    DOE PAGESBeta

    Hoss, Darby J.; Knepper, Robert; Hotchkiss, Peter J.; Tappan, Alexander S.; Boudouris, Bryan W.; Beaudoin, Stephen P.

    2016-03-23

    In this study, cohesive Hamaker constants of solid materials are measured via optical and dielectric properties (i.e., Lifshitz theory), inverse gas chromatography (IGC), and contact angle measurements. To date, however, a comparison across these measurement techniques for common energetic materials has not been reported. This has been due to the inability of the community to produce samples of energetic materials that are readily compatible with contact angle measurements. Here we overcome this limitation by using physical vapor deposition to produce thin films of five common energetic materials, and the contact angle measurement approach is applied to estimate the cohesive Hamakermore » constants and surface energy components of the materials. The cohesive Hamaker constants range from 85 zJ to 135 zJ across the different films. When these Hamaker constants are compared to prior work using Lifshitz theory and nonpolar probe IGC, the relative magnitudes can be ordered as follows: contact angle > Lifshitz > IGC. Furthermore, the dispersive surface energy components estimated here are in good agreement with those estimated by IGC. Due to these results, researchers and technologists will now have access to a comprehensive database of adhesion constants which describe the behavior of these energetic materials over a range of settings.« less

  8. An evaluation of complementary approaches to elucidate fundamental interfacial phenomena driving adhesion of energetic materials.

    PubMed

    Hoss, Darby J; Knepper, Robert; Hotchkiss, Peter J; Tappan, Alexander S; Boudouris, Bryan W; Beaudoin, Stephen P

    2016-07-01

    Cohesive Hamaker constants of solid materials are measured via optical and dielectric properties (i.e., Lifshitz theory), inverse gas chromatography (IGC), and contact angle measurements. To date, however, a comparison across these measurement techniques for common energetic materials has not been reported. This has been due to the inability of the community to produce samples of energetic materials that are readily compatible with contact angle measurements. Here we overcome this limitation by using physical vapor deposition to produce thin films of five common energetic materials, and the contact angle measurement approach is applied to estimate the cohesive Hamaker constants and surface energy components of the materials. The cohesive Hamaker constants range from 85zJ to 135zJ across the different films. When these Hamaker constants are compared to prior work using Lifshitz theory and nonpolar probe IGC, the relative magnitudes can be ordered as follows: contact angle>Lifshitz>IGC. Furthermore, the dispersive surface energy components estimated here are in good agreement with those estimated by IGC. Due to these results, researchers and technologists will now have access to a comprehensive database of adhesion constants which describe the behavior of these energetic materials over a range of settings. PMID:27042822

  9. In vitro color stability of provisional crown and bridge restoration materials.

    PubMed

    Ergün, Gülfem; Mutlu-Sagesen, Lâmia; Ozkan, Yalçin; Demirel, Erol

    2005-09-01

    Discoloration of provisional restorations can be an esthetic problem, especially when the treatment plan requires long-term provisionalization. In this study, therefore, we examined the effects of staining solution on the color stability of these provisional crown and bridge restoration materials: Structur, Temdent, and Tab 2000. Treatment solutions were namely carrot juice, tea, cola, light cola, and distilled water. Thirty samples were prepared for each type of provisional material, such that a total of 90 samples were prepared. The color value of each sample was measured with a colorimeter at baseline and after one day, one week, two weeks, and four weeks of immersion in various treatment solutions. Results were determined using the CIELAB system. Color change data were calculated and subjected to two-way analysis of variance. To examine significant interactions, one-way ANOVA and Tukey's multiple comparisons test were performed to identify differences between the solutions (p < or = 0.05). After four weeks of treatment, color difference values were found to range from 0.20 to 3.99 deltaE* units. The highest color difference values were obtained in carrot juice, cola, and tea with Structur samples after four weeks, where these values were categorized as "noticeable" and "unacceptable" color change values. Based on the results of this study, we do not recommend amine-containing Structur to be used as a provisional crown and bridge restorative material for treatments of a longer duration. PMID:16279724

  10. Comparison of two different silane compounds used for improving adhesion between fibres and acrylic denture base material.

    PubMed

    Vallittu, P K

    1993-09-01

    This study was aimed at clarifying the effects of two different silane compounds on the adhesion between the different fibres and acrylic resin. The fibres used as reinforcement in the acrylic resin test specimens were glass, carbon and aramid fibres and the silane treated and untreated versions of each type of the fibres were tested. The fracture resistance of the test specimens were assessed and the fibres were studied by a scanning electron microscope (SEM) to establish the adhesion between the fibres and acrylic resin. The results showed that silanization of glass and aramid fibres enhances the adhesion between the fibres and acrylic resin. The findings were confirmed by the SEM photographs taken. The use of a scanning electron microscope proved to be useful for the investigation of the adhesive properties of the materials used. PMID:10412475

  11. Composite film fabricated on biomedical material with corona streamer plasma processing to mitigate bacterial adhesion

    NASA Astrophysics Data System (ADS)

    Alhamarneh, Ibrahim; Pedrow, Patrick; Eskhan, Asma; Abu-Lail, Nehal

    2011-10-01

    Composite films might control bacterial adhesion and concomitant biofouling that afflicts biomedical materials. Different size molecules of polyethylene glycol (PEG) with nominal molecular weights 600, 2000, and 20000 g/mol were used to synthesize composite films with plasma processing and dip-coating procedures on surgical-grade 316L stainless steel. Before dip-coating, the substrate was pre-coated with plasma-polymerized di(ethylene glycol) vinyl ether (pp-EO2V) in an atmospheric pressure corona streamer plasma reactor. The PEG dip-coating step followed immediately in the same chamber due to the finite lifetime of radicals associated with freshly deposited pp-EO2V. Morphology of the composite film was investigated with an ESEM. FTIR confirmed incorporation of pp-EO2V and PEG species into the composite film. More investigations on the composite film were conducted by XPS measurements. Adhesion of the composite film was evaluated with a standard peel-off test. Stability of the composite film in buffer solution was evaluated by AFM. AFM was also used to measure the film roughness and thickness. Polar and non-polar contact angle measurements were included.

  12. Molecular Toxicology of Substances Released from Resin–Based Dental Restorative Materials

    PubMed Central

    Bakopoulou, Athina; Papadopoulos, Triantafillos; Garefis, Pavlos

    2009-01-01

    Resin-based dental restorative materials are extensively used today in dentistry. However, significant concerns still remain regarding their biocompatibility. For this reason, significant scientific effort has been focused on the determination of the molecular toxicology of substances released by these biomaterials, using several tools for risk assessment, including exposure assessment, hazard identification and dose-response analysis. These studies have shown that substances released by these materials can cause significant cytotoxic and genotoxic effects, leading to irreversible disturbance of basic cellular functions. The aim of this article is to review current knowledge related to dental composites’ molecular toxicology and to give implications for possible improvements concerning their biocompatibility. PMID:19865523

  13. Evaluation of Adhesive Bonding of Lithium Disilicate Ceramic Material with Duel Cured Resin Luting Agents

    PubMed Central

    Gundawar, Sham M.; Radke, Usha M.

    2015-01-01

    Purpose: The purpose of this vitro study was to comparatively evaluate the adhesive bonding of dual cured resin luting agents with lithium disilicate ceramic material. Materials and Methods: Porcelain laminate veneers were prepared with lithium disilicate ceramic material i.e. IPS Empress II( E-Max Press). These laminates were bonded with RelyX ARC, Panavia F 2.0, Variolink II, Duolink and Nexus NX3.The porcelain laminates were etched with 9.6% hydrofluoric acid (Pulpdent Corporation) for one minute, washed for 15 sec with three way syringe and dried for 15 sec with air syringe. The silane (Ultradent) was applied with the help of applicator tip in a single coat and kept undisturbed for one minute. The prepared surfaces of the premolars were treated with 37% phosphoric acid (Prime dent) for 15 sec, thoroughly rinsed and dried as per manufactures instructions. The shear bond test was carried out on all samples with the Universal testing machine (Instron U.S.A.) The scanning electron microscopic study was performed at the fractured interface of representative samples from each group of luting agents. Result: In this study, the highest value of shear bond strength was obtained for NEXUS NX3 and the lowest for VARIOLINK II. Conclusion: The difference in bond strength can be interpreted as the difference in fracture resistance of luting agents, to which shearing load was applied during the shear bond strength test. It is inferred from this study that the composition of the luting agent determines the adhesive characteristics in addition to surface treatment and bonding surface area. PMID:25859514

  14. Materials study for interfacial adhesion and reliability of microelectronics packaging structures

    NASA Astrophysics Data System (ADS)

    Dai, Xiang

    Multilayers and interfaces are ubiquitous in microelectronics devices, interconnect and packaging structures. Because of the differential thermal expansion of the dissimilar materials, thermal excursions from manufacturing processes and component operations cause thermal stresses which often drive delamination at various interfaces. As the interface integrity becomes the major concern of performance, yield, and reliability, the need to evaluate the fracture and delamination behavior of various interfaces increases. The present work focuses on a typical flip-chip-on-board (FCOB) packaging structure. The FCOB package utilizes a particulate filled liquid epoxy (underfill) to adhere the chip to the board for improved reliability of solder interconnections. However, underfill delamination from chip and/or board is most commonly observed in premature failure of flip-chip-on-board packages. The objectives of this work are to develop experimental and analysis techniques for quantifying the underfill interface fracture resistance, to identify interface adhesion and toughening mechanisms, and to develop a methodology for the reliability assessment of the interface integrity. Series of experiments and analyses are conducted to investigate the adhesion and fracture behaviors of the underfill/silicon and underfill/board interfaces. The experimental techniques for the interface fracture experiments are developed to produce the double-cantilever-beam (DCB) sandwich specimens and to establish a reproducible testing protocol. To extract the interfacial fracture energies, a closed-form solution is developed based on a beam-on-elastic-foundation model for DCB underfill/silicon specimens. A corrected beam theory model is adopted for DCB underfill/board specimens. A two-dimensional elastoplastic finite element analysis (FEA) model is also implemented to examine effects of mode-mixity, thermal/residual stresses, and underfill plasticity. The fracture energies of underfill/silicon and

  15. Heat generation caused by ablation of dental restorative materials with an ultra short pulse laser (USPL) system

    NASA Astrophysics Data System (ADS)

    Braun, Andreas; Wehry, Richard; Brede, Olivier; Frentzen, Matthias; Schelle, Florian

    2011-03-01

    The aim of this study was to assess heat generation in dental restoration materials following laser ablation using an Ultra Short Pulse Laser (USPL) system. Specimens of phosphate cement (PC), ceramic (CE) and composite (C) were used. Ablation was performed with an Nd:YVO4 laser at 1064 nm and a pulse length of 8 ps. Heat generation during laser ablation depended on the thickness of the restoration material. A time delay for temperature increase was observed in the PC and C group. Employing the USPL system for removal of restorative materials, heat generation has to be considered.

  16. Effects of storage media on physical properties of selected tooth coloured restorative materials.

    PubMed

    Sadaghiani, Leili; Adusei, Gabriel; Rees, Jeremy

    2009-09-01

    It is known that storage media can affect the physical properties of some restorative dental materials. The purpose of this laboratory study was to investigate the possible effects of storage media on physical properties of a conventional glass-ionomer, a resin modified glass ionomer and a compomer. Specimens of the restorative materials in the study (FujiII LC, FujiIX and Dyract EXTRA) were prepared. The specimens were stored in either water or artificial saliva with or without exposure to Listerine. The compressive and diametral tensile strength and Vickers hardness of these materials were tested at 24 hours, 1 week, 4 weeks and 12 weeks. Compressive and diametral tensile strength for FujiII LC and Fuji IX had increased at 12 weeks. A decrease was observed for Dyract EXTRA in the same period. No significant differences were observed between the storage media (P > 0.01). Vickers hardness values fluctuated during the testing period, with a pattern being consistent for each material. Storage of materials investigated for the period in this study resulted in superior compressive and diametral tensile strength for Fuji II LC and FujiIX. The opposite was true for Dyract EXTRA. Effects of time were found to be more pronounced than the media (P < 0.01). PMID:19839187

  17. Time-dependent strength and fatigue resistance of dental direct restorative materials.

    PubMed

    Lohbauer, Ulrich; Frankenberger, Roland; Krämer, Norbert; Petschelt, Anselm

    2003-12-01

    Elastic modulus (EM), initial fracture strength (FS) and flexural fatigue limit (FFL) of dental restorative materials were measured in a simulated oral environment to correlate mechanical response under the influence of water with the chemical nature of the test materials under investigation. One resin composite (RC; Tetric Ceram, Ivoclar-Vivadent Corp., Liechtenstein), an ion-leaching resin composite (ILRC; Ariston pHc, Ivoclar-Vivadent Corp., Liechtenstein) a compomer (CO; Dyract AP, Dentsply Corp., USA) and a glass-ionomer cement (GIC; Ketac Molar, 3MEspe Corp., Germany) were tested. Static EM, FS and dynamic FFL experiments were performed. The FFL was determined under cyclic loading for 10(5) cycles in terms of a staircase approach. The materials were stored for 1, 8, 30, 90 and 180 days in 37 degrees C distilled water, respectively. The RC degraded over time due to water adsorption followed by failure within the resin matrix. The ILRC suffered from a pronounced decrease in FS as well as in FFL due to a constant ion-leaching and macroscopic crack growth. CO failed over time due to resin-filler interface cracking. The GIC exhibited improved mechanical performance over time due to a post-hardening mechanism. The results reveal the necessity for substantial preclinical evaluation of direct restorative materials. The material parameters under investigation are capable of predicting clinical performance over time. PMID:15348497

  18. Erosive Potential of Cola and Orange Fruit Juice on Tooth Colored Restorative Materials

    PubMed Central

    Rajavardhan, K; Sankar, AJS; Kumar, MGM; Kumar, KR; Pranitha, K; Kishore, KK

    2014-01-01

    Background: Erosion is a common condition which manifests due to consumption of high caloric and low pH acidic food stuffs such as carbonated drinks and fruit juices which cause irreversible damage to dental hard tissues and early deterioration of the dental restorations. Aim: The main aim of this study is to evaluate and to compare the erosive potential of carbonated drink (cola) and fruit juice (orange fruit juice) by measuring the surface roughness (Ra) values on two commonly used dental restorative materials. Materials and Methods: A total of 36 specimens each were prepared using both testing materials, compomer (Group I) and giomer (Group II). Six specimens in each group were discarded due to wide variation in pre exposed Ra values and the remaining 30 specimens in each group were further sub divided into 10 samples each according to the testing media used. Immersion regime was followed according to Von Fraunhofer and Rogers. The pre and post immersion surface roughness values were recorded using a profilometer. Results: Both tested materials showed statistically-significant surface erosion (P < 0.01) when exposed to cola and orange fruit juice than the control group (water). Discussion: Compomer showed more surface roughness when compared to giomer when exposed to the three tested media which can be attributed to the variation in filler content, decomposition of resin matrix and fallout of the fillers in composites when exposed to acidic drinks. Other factors responsible for this significant erosion were also discussed. Conclusions: Significant surface changes of the dental restorative materials can take place when exposed to low pH drinks for a prolonged period. PMID:25364590

  19. Effects of Current Provisional Restoration Materials on the Viability of Fibroblasts

    PubMed Central

    Ulker, Mustafa; Ulker, H. Esra; Zortuk, Mustafa; Bulbul, Mehmet; Tuncdemir, Ali Riza; Bilgin, M. Selim

    2009-01-01

    Objectives: The aim of the present study was to evaluate the cytotoxic effects of three different provisional restoration materials on fibroblasts. Two bis-acrylic based [Tempofit Duomix (Detax), Protemp 3 Garant (3M ESPE)] and one urethan dimethacrylate [Revotek LC (GC Corporation)] based provisional restoration materials used. Methods: Materials were prepared according to the manufacturers’ instructions in standard teflon disks (2×5 mm) and four samples were extracted in 7 ml of Basal Medium Eagle with 10% new born calf serum and 100 mg/ml penicillin/streptomycin for 24 hours. The L929 fibroblast cells were plated (25.000 cells/ml) in well plates, and maintained in a CO2 incubator at 37°C for 24h. After 24 hours, the incubation medium was replaced by the immersed medium in which the samples were stored and the L929 fibroblasts were incubated in contact with eluates for 24 hours at 37°C for 24h. The fibroblast cell viability was analyzed by measuring the mitochondrial activity with the methyltetrazolium test (MTT). Twelve well used for each specimen and experiment repeated for two times. The data was statistically analyzed by Mann-Whitney U tests. Results: The results showed that, Revotek LC and Protemp 3 Garant were not cytotoxic for fibroblast cells when compared to control group (P>.05). However, Tempofit duomix was cytotoxic for L929 fibroblasts when compared to control group and other tested materials (P<.05). Conclusions: Taking into consideration the limitations of an in vitro study, our study indicate that provisional restoration materials might have cytotoxic effects on fibroblasts and should be selected carefully for clinical applications. PMID:19421391

  20. Effect of Whitening Dentifrice on Micro Hardness, Colour Stability and Surface Roughness of Aesthetic Restorative Materials

    PubMed Central

    Basappa, N.; Prabhakar, AR; Raju, OS; Lamba, Gagandeep

    2016-01-01

    Introduction Whitening agents present in the novel whitening dentifrices may have deleterious effects over the aesthetic restorations. Aim The present study evaluated the invitro effect of whitening dentifrice on micro hardness, colour stability and surface roughness on aesthetic restorative materials. Materials and Methods Forty specimens each of compomer and of composite were prepared using brass mould. Specimens were equally divided into 4 groups. Group I (20 disks of compomer are subjected to brushing with conventional tooth paste) Group II (20 disks of composite subjected to brushing with conventional tooth paste), Group III (20 disks of compomer subjected to brushing with whitening tooth paste). Group IV (20 disks of composite subjected to brushing with whitening toothpaste). Each group was further divided into two subgroups, where 10 sample were subjected for two weeks of brushing with respective tooth paste and other 10 were subjected for four weeks of brushing. For the evaluation of micro hardness, colour stability and surface roughness, micro hardness testing machine, spectrophotometer and surface testing machine were used respectively. Initial and final readings were taken for each specimen and difference obtained was subjected to statistical analysis. One-way ANOVA was used for multiple group comparison followed by post-hoc Tukey’s-test. The paried t-test was used for intra group comparison and unpaired t-test for comparing independent sample groups. Results The compomer and composite showed no significant difference in micro hardness either with conventional or whitening tooth paste both at two and four weeks. Although there was a highly significant colour change observed after using whitening tooth paste for both compomer and composite. Regarding surface roughness, there was a significant change in roughness in both conventional and whitening tooth paste with compomer and composite. However, whitening tooth paste had a significant change in surface

  1. Preservation-based approaches to restore posterior teeth with amalgam, resin or a combination of materials.

    PubMed

    Baghdadi, Ziad D

    2002-02-01

    This review is a systematic assessment, from the literature, of the status quo of dental amalgam, resin-based composite and glass-ionomer restorations for carious lesions as it applies to new concepts, coupled with clinical research. Scientifically based and practical new materials and techniques are recommended to include in contemporary practice throughout the world. Clinical and laboratory studies which have been carried out in light of modern conservative principles, and in light of the current emphasis of treating dental caries as a disease process were reviewed and discussed. An approach to managing carious lesions based upon selected advantages of dental amalgam, resin-based composite and glass-ionomer technology applied to what is termed "preservation-based" approaches to restoring teeth has been synthesized. Researched evidence contradicts the notion of "extension for prevention" in favor of maintaining sound tooth structure which would translate into more patients with healthy dentitions for entire lifetimes. PMID:12074231

  2. Fracture Toughness of Veneering Ceramics for Fused to Metal (PFM) and Zirconia Dental Restorative Materials

    PubMed Central

    Quinn, Janet B.; Quinn, George D.; Sundar, Veeraraghaven

    2010-01-01

    Veneering ceramics designed to be used with modern zirconia framework restorations have been reported to fracture occasionally in vivo. The fracture toughness of such veneering ceramics was measured and compared to that of conventional feldspathic porcelain veneering ceramics for metal framework restorations. The fracture toughness of the leucite free veneer was measured to be 0.73 MPa m ± 0.02 MPa m, which is less than that for the porcelain fused to metal (PFM) veneering ceramic: 1.10 MPa ± 0.2 MPa. (Uncertainties are one standard deviation unless otherwise noted.) The surface crack in flexure (SCF) method was suitable for both materials, but precrack identification was difficult for the leucite containing feldspathic porcelain PFM veneer. PMID:21833158

  3. Comparison of microleakage from stainless steel crowns margins used with different restorative materials: An in vitro study

    PubMed Central

    Memarpour, Mahtab; Derafshi, Reza; Razavi, Mahshid

    2016-01-01

    Background: Obtaining optimal marginal adaption with prefabricated stainless steel crowns (SSCs) is difficult, especially after removing dental caries or defects in cervical areas. This situation requires the use of an SSC after tooth reconstruction. This study evaluated microleakage and material loss with five restorative materials at SSC margins. Materials and Methods: One hundred and twenty primary molar teeth were randomly divided into six groups (n = 20). Class V cavities were prepared on the buccal surfaces of the teeth in groups 1-5. Cavities were restored with amalgam, resin-based composite, glass ionomer (GI), zinc phosphate, or reinforced zinc oxide eugenol (Zonalin). Group 6 without cavity preparation was used as a control. Restorations with SSCs were prepared according to standard methods. Then, SSCs were fitted so that the crown margins overlaid the restorative materials and cemented with GI. After thermocycling, the specimens were placed in 0.5% fuchsin and sectioned. The proportions of mircoleakage and material loss were evaluated with a digital microscope. Statistical analysis was performed with Kruskal–Wallis and Mann–Whitney tests. Results: The groups differed significantly (P < 0.001). Amalgam and GI showed the least microleakage. Amalgam restorations had significantly less microleakage than the other materials (P < 0.05). Microleakage was greatest with resin-based composite, followed by Zonalin. Material loss was greater in samples restored with Zonalin and zinc phosphate. Conclusion: When SSC margins overlaid the restoration materials, cavity restoration with amalgam or GI before SSC placement led to less microleakage and material loss. Regarding microleakage and material loss, resin-based composite, zinc phosphate, and Zonalin were not suitable options. PMID:26962309

  4. Matching the optical properties of direct esthetic dental restorative materials to those of human enamel and dentin

    NASA Astrophysics Data System (ADS)

    Ragain, James Carlton, Jr.

    One of the goals of the restorative dentist is to restore the appearance of the natural dentition. Clinical matching of teeth and restorative materials are seldom accurate and shade selection techniques are subjective. The first specific aim of this research was to characterize the optical absorption and scattering that occurs within enamel, dentin, and composite resin and compomer restorative materials and to relate those phenomena to translucency and color. The second aim was to evaluate small color differences among composite restorative materials which would be detectable by humans. The last aim was to lay the foundation for developing an improved model of specifying layers of dental restorative materials in order to match the translucency and color to those of human enamel. The Kubelka-Munk theory was validated for enamel, dentin, and the restorative materials. These tissues and materials were then characterized in terms of their color parameters. Tooth cores were also characterized in terms of color space parameters. Human subjects were evaluated for their abilities to discriminate small color differences in the dental composite resin materials. The following conclusions were derived from this study: (1) Kubelka-Munk theory accurately predicts the diffuse reflectance spectra of enamel, dentin, and the direct esthetic dental restorative materials studied. (2) Scattering and absorption coefficients of the dental tissues and esthetic restorative materials can be directly calculated from diffuse reflectance measurements of a uniformly thick slab of tissue/material using black and white backings and the appropriate refractive index. (3) For tooth cores, there is a positive correlation between L* and b* and a negative correlation between L* and a*. (4) The range of translucency parameters for the restorative materials studied does not match those of enamel and dentin. (5) None of the shades of the dental composite resin restorative materials studied fit into the

  5. The role of damage-softened material behavior in the fracture of composites and adhesives

    NASA Technical Reports Server (NTRS)

    Ungsuwarungsri, T.; Knauss, W. G.

    1986-01-01

    Failure mechanisms of materials under very high strains experienced at and ahead of the crack tip such as formation, growth, and interaction of microvoids in ductile materials, microcracks in brittle solids or crazes in polymers and adhesives are represented by one-dimensional, nonlinear stress-strain relations possessing different ways by which the material loses capacity to carry load up to fracture or total separation. A double cantilever beam (DCB) type specimen is considered. The nonlinear material is confined to a thin strip between the two elastic beams loaded by a wedge. The problem is first modeled as a beam on a nonlinear foundation. The pertinent equation is solved numerically as a two-point boundary value problem for both the stationary and the quasi-stationay propagating crack. A finite element model is then used to model the problem in more detail in order to assess the adequacy of the beam model for the reduction of experimental data to determine in-situ properties of the thin interlayer.

  6. The selection of contemporary restorative materials: anecdote vs. evidence-based?

    PubMed

    Donovan, Terry E

    2006-02-01

    The contemporary practitioner is faced with a bewildering number of options from which to choose when selecting restorative materials. There are not only many different types of materials available, but also numerous options for any given group of materials. For example, many manufacturers offer their customers three or even four different dentin bonding agents. The sheer number of available products is in itself overwhelming. When coupled with aggressive marketing strategies, misinformation supplied by paid clinicians at many seminars and lectures, and infomercials disguised as scientific articles in many of the trade journals, it is little wonder that the average ethical practitioner is frustrated when attempting to make rational choices. Clinicians use information gleaned from a variety of sources to make these difficult decisions. This article will attempt to evaluate the validity of these sources and will provide a philosophical matrix to assist the practitioner in making rational decisions relative to materials selection. PMID:16724468

  7. Investigation of thiol-ene and thiol-ene-methacrylate based resins as dental restorative materials

    PubMed Central

    Cramer, Neil B.; Couch, Charles L.; Schreck, Kathleen M.; Carioscia, Jacquelyn A.; Boulden, Jordan E.; Stansbury, Jeffrey W.; Bowman, Christopher N.

    2009-01-01

    Objectives The objective of this work was to evaluate thiol-norbornene and thiol-ene-methacrylate systems as the resin phase of dental restorative materials and demonstrate their superior performance as compared to dimethacrylate materials. Methods Polymerization kinetics and overall functional group conversions were determined by Fourier transform infrared spectroscopy (FTIR). Flexural strength and modulus were determined with a 3-point flexural test. Polymerization-induced shrinkage stress was measured with a tensometer. Results Thiol-ene polymer systems were demonstrated to exhibit advantageous properties for dental restorative materials in regards to rapid curing kinetics, high conversion, and low shrinkage and stress. However, both the thiol-norbornene and thiol-allyl ether systems studied here exhibit significant reductions in flexural strength and modulus relative to BisGMA/TEGDMA. By utilizing the thiol-ene component as the reactive diluent in dimethacrylate systems, high flexural modulus and strength are achieved while dramatically reducing the polymerization shrinkage stress. The methacrylate-thiol-allyl ether and methacrylate-thiol-norbornene systems both exhibited equivalent flexural modulus (2.1 ± 0.1 GPa) and slightly reduced flexural strength (95 ± 1 and 101 ± 3 MPa, respectively) relative to BisGMA/TEGDMA (flexural modulus; 2.2 + 0.1 GPa and flexural strength; 112 ± 3 MPa). Both the methacrylate-thiol-allyl ether and methacrylate-thiol-norbornene systems exhibited dramatic reductions in shrinkage stress (1.1 ± 0.1 and 1.1 ± 0.2 MPa, respectively) relative to BisGMA/TEGDMA (2.6 ± 0.2 MPa). Significance The improved polymerization kinetics and overall functional group conversion, coupled with reductions in shrinkage stress while maintaining equivalent flexural modulus, result in a superior overall dental restorative material as compared to traditional bulk dimethacrylate resins. PMID:19781757

  8. An in vitro study of the properties influencing Staphylococcus epidermidis adhesion to prosthetic vascular graft materials.

    PubMed Central

    Harris, J M; Martin, L F

    1987-01-01

    This study examines the influence of the properties of various vascular graft materials on the bacterial adherence process of two different strains of Staphylococcus epidermidis (mucous and normucous producing). Dacron grafts (both knitted and woven), Teflon grafts, and Dacron grafts coated with one and two layers of silicone were studied because these materials differ significantly in porosity, hydrophobicity, and surface charge (zeta potential). Graft segments were immersed in 3H-labeled bacteria solution for periods ranging from 5 to 180 minutes and liquid scintillation techniques were used to quantify bacterial adherence. The porous knitted Dacron material had a significantly higher rate of bacterial adherence than either the woven Dacron or Teflon (p less than 0.05). Silicone coating (either one or two layers) reduced adherence by a factor of four for the knitted Dacron (p less than 0.05) and by a factor of two for woven Dacron (p less than 0.05). The mucous producing strain of S. epidermidis displayed significantly better adherence to woven and knitted Dacron than the normucous producing strain, but only when 0.25% dextrose was added to the bacteria solution. These findings indicate that the highly porous knitted Dacron grafts have the highest propensity for bacterial adhesion. Graft materials with the most negative zeta potentials are more resistant to bacterial adherence. Silicone coating of Dacron material significantly changed adherence characteristics, suggesting that this may be a viable strategy for protecting implantable medical devices containing materials to which bacteria readily adhere. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5A and B. Fig. 6A and B. Fig. 7. PMID:2960278

  9. The assessment of surface roughness and microleakage of eroded tooth-colored dental restorative materials

    PubMed Central

    Hussein, Thulfiqar Ali; Bakar, Wan Zaripah Wan; Ghani, Zuryati Ab; Mohamad, Dasmawati

    2014-01-01

    Objectives: To investigate the effect of acidic solution on surface roughness and microleakage of tooth-colored restorative materials. Materials and Methods: A 160 box-shaped cavities were prepared on the buccal surfaces of 160 human molars, and assigned to four groups: Group A restored with Ketac™ Molar Easymix, Group B with Fuji II™ LC, Group C with Ketac™ N100, and Group D with Filtek™ Z250, and subdivided into study and control groups (n = 20). Study groups were immersed in lemon juice (pH = 2.79) for 24 h, whilst controlgroups in deionized distilled water. All samples were immersed in 2% methylene blue dye, sectioned into two equal halves for surface roughness, and microleakage tests. Data were analyzed using Mann–Whitney and Kruskal–Wallis tests at P < 0.05. Results: There was a significant difference in surface roughness of Ketac™ Molar, Fuji II™ LC, and Ketac™ N100. No significant difference was found in microleakage of Ketac™ Molar and Fuji II™ LC; however, there were significant differences in the gingival margin of Ketac™ N100, and the occlusal margin of Filtek™ Z250. Conclusions: All glass ionomer cements were eroded after exposure to the acidic drink. Filtek™ Z250 and Ketac™ Molar Easymix showed more microleakage. All materials showed more microleakage at the gingival margins. PMID:25506139

  10. A test method for determining adhesion forces and Hamaker constants of cementitious materials using atomic force microscopy

    SciTech Connect

    Lomboy, Gilson; Sundararajan, Sriram; Wang Kejin; Subramaniam, Shankar

    2011-11-15

    A method for determining Hamaker constant of cementitious materials is presented. The method involved sample preparation, measurement of adhesion force between the tested material and a silicon nitride probe using atomic force microscopy in dry air and in water, and calculating the Hamaker constant using appropriate contact mechanics models. The work of adhesion and Hamaker constant were computed from the pull-off forces using the Johnson-Kendall-Roberts and Derjagin-Muller-Toropov models. Reference materials with known Hamaker constants (mica, silica, calcite) and commercially available cementitious materials (Portland cement (PC), ground granulated blast furnace slag (GGBFS)) were studied. The Hamaker constants of the reference materials obtained are consistent with those published by previous researchers. The results indicate that PC has a higher Hamaker constant than GGBFS. The Hamaker constant of PC in water is close to the previously predicted value C{sub 3}S, which is attributed to short hydration time ({<=} 45 min) used in this study.

  11. Restoration of large cranial defect for cranioplasty with alloplastic cranial implant material: a case report.

    PubMed

    Goyal, Shelly; Goyal, Mukesh Kumar

    2014-06-01

    Cranial defects result either from trauma or after intentional osteocraniotomies or external decompression craniectomies. These defects occur most frequently during wartime, but their incidence during peacetime, as a result of accident or disease, makes knowledge of cranioplasty useful to the interested practitioner. Most cranial defects will have some variable proportion of cosmetic and mechanical aspects, and the decision regarding cranioplasty must be influenced by the patient's age, prognosis, activity level and the specific conditions of the scalp and calvarium. This case report is oriented towards post-traumatic restoration of large cranial defect with alloplastic heat-cure poly methyl methacrylate resin material. PMID:24757358

  12. Surface energy modification for biomedical material by corona streamer plasma processing to mitigate bacterial adhesion

    NASA Astrophysics Data System (ADS)

    Alhamarneh, Ibrahim; Pedrow, Patrick

    2011-10-01

    Bacterial adhesion initiates biofouling of biomedical material but the processes can be reduced by adjusting the material's surface energy. The surface of surgical-grade 316L stainless steel (316L SS) had its hydrophilic property enhanced by processing in a corona streamer plasma reactor using atmospheric pressure Ar mixed with O2. Reactor excitation was 60 Hz ac high-voltage (<= 10 kV RMS) applied to a multi-needle-to-grounded-torus electrode configuration. Applied voltage and streamer current pulses were monitored with a broadband sensor system. When Ar/O2 plasma was used, the surface energy was enhanced more than with Ar plasma alone. Composition of the surface before and after plasma treatment was characterized by XPS. As the hydrophilicity of the treated surface increased so did percent of oxygen on the surface thus we concluded that reduction in contact angle was mainly due to new oxygen-containing functionalities. FTIR was used to identify oxygen containing groups on the surface. The aging effect that accompanies surface free energy adjustments was also observed.

  13. Combined effect of staining substances on the discoloration of esthetic Class V dental restorative materials.

    PubMed

    Lee, Yong-Keun; Powers, John M

    2007-01-01

    The purpose of this study was to determine the combined effect of an organic substance (mucin as a substitute for salivary organic substances), chlorhexidine, and an iron compound/tea solution on the changes in the color of esthetic Class V dental restorative materials. Color of a glass ionomer, resin-modified glass ionomer, compomer and flowable resin composite of A2 shade, respectively, was determined according to the CIELAB color scale relative to the standard illuminant D65. Color was measured at baseline, and after sequential immersion in the following substances: Step-1, mucin in PBS (MCP) for 48 h; Step-2, chlorhexidine (CHX) for 24 h; Step-3, iron compound (IRN) or tea solution (TEA) up to 7 days; and Step-4, ultrasonic cleaning for 1 h. Color change (DeltaE(ab )*) was calculated by the equation: DeltaE(ab)* = [(DeltaL*)(2) + (Deltaa*)(2) + (Deltab*)(2)](1/2), of which DeltaL(*) indicates changes in value, Deltaa(*) indicates changes in red-green parameter and Deltab(*) indicates changes in yellow-blue parameter. DeltaE(ab)* values after immersion in MCP and CHX were compared, and DeltaE(ab)* values after immersion in IRN or TEA, and subsequent ultrasonic cleaning were compared with respect to the restorative material and immersion substance. DeltaE(ab)* and changes in the color parameters (DeltaL(*), DeltaC(ab)* and DeltaH(ab)*) were analyzed by repeated measures, analysis of variance and a post-hoc test at the 0.05 level of significance. Color changes after immersion in MCP were acceptable (DeltaE(ab)* < 3.3), and those after immersion in CHX were generally acceptable. The range of DeltaE(ab)* values after immersion in IRN was 3.1-19.6, and that after ultrasonic cleaning was 2.4-9.6. The range of DeltaE(ab)* values after immersion in TEA was 10.7-21.1, and that after ultrasonic cleaning was 11.9-14.5. Color changes of four Class V restorative materials after combined treatment with mucin, chlorhexidine and an iron compound/tea solution were not acceptable

  14. The effect of three finishing systems on four esthetic restorative materials.

    PubMed

    Hoelscher, D C; Neme, A M; Pink, F E; Hughes, P J

    1998-01-01

    Previous studies have investigated the finishing and smoothness of composite and traditional glass-ionomer restorations, but few have included resin-modified glass-ionomer cements or more recent finishing systems. The results of using three different finishing systems (Sof-Lex, Enhance, finishing burs) on two composites (Silux, Prisma TPH), a traditional glass ionomer (Ketac-Fil), and a resin-modified glass ionomer (Fuji II LC) were studied. Sixty samples were condensed into sectioned acrylic tubes, covered with a Mylar matrix plus a glass slide at each surface, then cured as per the manufacturers' instructions. Samples were randomized to three groups of five for each material and testing with a Surfanalyzer 4000 of unfinished samples (cured with Mylar matrix) was done to obtain baseline average surface roughness (Ra). Samples were then finished as per the manufacturers' instructions using polishing disks, abrasive impregnated disks, and finishing burs before further surface testing. Samples finished with burs and with abrasive impregnated disks were further polished using polishing paste (Prisma Gloss) and again tested. Data were analyzed with ANOVA testing and Tukey's HSD pairwise comparison. Initial testing after randomization to groups showed no significant difference in surface roughness (P = 0.24). Two-factor analysis revealed no significant difference between materials (P = 0.34), a significant difference in method of finish (P < or = 0.00), with no significant interaction between type of material and method of finish (P = 0.11). Aluminum oxide disk and impregnated disk systems provided the best finish for microfilled composite and both glass-ionomer materials (P < or = 0.00). No significant difference in method of finish existed with the hybrid composite (P = 0.07). Overall, esthetic restorative material finishing is best accomplished using abrasive impregnated disks or aluminum oxide disks. Finishing burs gave a significantly rougher surface than the

  15. Analysis of Resin-Dentin Interface Morphology and Bond Strength Evaluation of Core Materials for One Stage Post-Endodontic Restorations

    PubMed Central

    Bitter, Kerstin; Gläser, Christin; Neumann, Konrad; Blunck, Uwe; Frankenberger, Roland

    2014-01-01

    Purpose Restoration of endodontically treated teeth using fiber posts in a one-stage procedure gains more popularity and aims to create a secondary monoblock. Data of detailed analyses of so called “post-and-core-systems” with respect to morphological characteristics of the resin-dentin interface in combination with bond strength measurements of fiber posts luted with these materials are scarce. The present study aimed to analyze four different post-and-core-systems with two different adhesive approaches (self-etch and etch-and-rinse). Materials and Methods Human anterior teeth (n = 80) were endodontically treated and post space preparations and post placement were performed using the following systems: Rebilda Post/Rebilda DC/Futurabond DC (Voco) (RB), Luxapost/Luxacore Z/Luxabond Prebond and Luxabond A+B (DMG) (LC), X Post/Core X Flow/XP Bond and Self Cure Activator (Dentsply DeTrey) (CX), FRC Postec/MultiCore Flow/AdheSE DC (Ivoclar Vivadent) (MC). Adhesive systems and core materials of 10 specimens per group were labeled using fluorescent dyes and resin-dentin interfaces were analyzed using Confocal Laser Scanning Microscopy (CLSM). Bond strengths were evaluated using a push-out test. Data were analyzed using repeated measurement ANOVA and following post-hoc test. Results CLSM analyses revealed significant differences between groups with respect to the factors hybrid layer thickness (p<0.0005) and number of resin tags (p = 0.02; ANOVA). Bond strength was significantly affected by core material (p = 0.001), location inside the root canal (p<0.0005) and incorporation of fluorescent dyes (p = 0.036; ANOVA). CX [7.7 (4.4) MPa] demonstrated significantly lower bond strength compared to LC [14.2 (8.7) MPa] and RB [13.3 (3.7) MPa] (p<0.05; Tukey HSD) but did not differ significantly from MC [11.5 (3.5) MPa]. Conclusion It can be concluded that bond strengths inside the root canal were not affected by the adhesive approach of the post

  16. Reinforcement of Unsupported Enamel by Restorative Materials and Dentin Bonding Agents: An In Vitro Study

    PubMed Central

    Mirzaei, M.; Ghavam, M.; Rostamzadeh, T.

    2010-01-01

    Objective: Preservation of unsupported occlusal enamel after removal of underlying carious dentin may result in maintenance of aesthetics as well as wear resistance against the opposing enamel. This study investigates the influence of different restorative materials and bonding agents on reinforcement of unsupported enamel in molars and compares it with sound dentin. Materials and Methods: In this in vitro study, forty- five extracted human molars were selected and randomly divided into five groups of nine. All lingual cusps were cut off. The dentin underlying the buccal cusps was removed in all groups except the positive control. The negative control group received no restorations. After application of varnish and Panavia F, spherical amalgam (Sina) and after application of Single-Bond (3M), composite resin (Tetric Ceram) was used to replace missing dentin. All specimens were thermocycled, then mounted in acrylic resin using a surveyor. Lingual inclination of facial cusps was positioned horizontally. Load was applied by an Instron machine at a crosshead speed of 10 mm/min until fracture. Data were subjected to ANOVA (one way) and Post hoc Test (Duncan). Results: Statistically significant differences were found between the five groups (P<0.001); however, no significant difference was revealed between bonded amalgam and the positive control groups (P=0.762). Composite and amalgam had the same effect (P=0.642), while the composite and negative group had no significant difference (P=0.056). Conclusion: Bonded amalgam systems (Panavia F) could reinforce the undermined occlusal enamel effectively. PMID:21998780

  17. The Temperature Dependence of Micro-Leakage between Restorative and Pulp Capping Materials by Cu Diffusion.

    PubMed

    H, Kamalak; A, Mumcu; S, Altin

    2015-01-01

    We used the Cu ions for the leakage analysis between pulp capping and restorative materials. Theoretically, Cu has more advantages than Ag ions due to their smaller radii (rCu (2+)=73 pm and rAg (2+)=94 pm), lower mass density (dCu=8.96 g/cm(3) and dAg=10.49 g/cm(3)) and higher radio opacity which can be more useful by X-ray or EDX detectors, cheaper price and more abundance in planet when compared with Ag element which is generally used in the leakage studies. The micro leakage between dental restorations and pulp capping materials has been determined by using Micro Computed Tomography, Scanning Electron Microscopy and EDX analysis. It is found that the leakage has temperature dependent mechanism which increases with the increasing temperature. As a result, using Cu solution for leakage studies in dentine is an effective and easy method which can be used in dental science. PMID:25926897

  18. The Temperature Dependence of Micro-Leakage between Restorative and Pulp Capping Materials by Cu Diffusion

    PubMed Central

    H, Kamalak; A, Mumcu; S, Altin

    2015-01-01

    We used the Cu ions for the leakage analysis between pulp capping and restorative materials. Theoretically, Cu has more advantages than Ag ions due to their smaller radii (rCu2+=73 pm and rAg2+=94 pm), lower mass density (dCu=8.96 g/cm3 and dAg=10.49 g/cm3) and higher radio opacity which can be more useful by X-ray or EDX detectors, cheaper price and more abundance in planet when compared with Ag element which is generally used in the leakage studies. The micro leakage between dental restorations and pulp capping materials has been determined by using Micro Computed Tomography, Scanning Electron Microscopy and EDX analysis. It is found that the leakage has temperature dependent mechanism which increases with the increasing temperature. As a result, using Cu solution for leakage studies in dentine is an effective and easy method which can be used in dental science. PMID:25926897

  19. 76 FR 65212 - Henkel Corporation, Currently Known as Henkel Electronic Materials, LLC, Electronic Adhesives...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-20

    ... published in the Federal Register on August 2, 2010 (75 FR 45163). At the request of the State agency, the..., LLC, Electronic Adhesives Division, Including On-Site Leased Workers from Aerotek Professional... 12, 2010, applicable to workers of Henkel Corporation, Electronic Adhesives Division, including...

  20. Radio-opacity of core materials for all-ceramic restorations.

    PubMed

    Okuda, Yuji; Noda, Makoto; Kono, Hiroshi; Miyamoto, Motoharu; Sato, Hideo; Ban, Seiji

    2010-01-01

    The aim of this study was to investigate and compare the radio-opacity of core materials for all-ceramic restorations, such as zirconia (NANOZR and Y-TZP) and alumina, against commercially pure titanium (cpTi) and aluminum. X-ray images were taken under general settings using an X-ray film. The X-ray film images were scanned using a digital scanner, and the darkness at the central area of each specimen image was quantitatively analyzed using an image analysis software. Amongst the materials investigated, alumina showed the most transparency against X-rays. Conversely, both types of zirconia showed the highest radio-opacity, whereby that of NANOZR was slightly lower than that of Y-TZP. This was because NANOZR contained 30 vol% of alumina and its density was also slightly lower than that of Y-TZP. PMID:20379010

  1. Application of nanotechnology to control bacterial adhesion and patterning on material surfaces

    PubMed Central

    Costello, Cait M.; Yeung, Chun L.; Rawson, Frankie J.; Mendes, Paula M.

    2012-01-01

    Bacterial adhesion and biofilm formation on surfaces raises health hazard issues in the medical environment. Previous studies of bacteria adhesion have focused on observations in their natural/native environments. Recently, surface science has contributed in advancing the understanding of bacterial adhesion by providing ideal platforms that attempt to mimic the bacteria's natural environments, whilst also enabling concurrent control, selectivity and spatial control of bacterial adhesion. In this review, we will look at techniques of how nanotechnology is used to control cell adhesion on a planar scale, in addition to describing the use of nanotools for cell micropatterning. Additionally, it will provide a general background of common methods for nanoscale modification enabling biologist unfamiliar with nanotechnology to enter the field. PMID:24273593

  2. Material characterization of structural adhesives in the lap shear mode. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Schenck, S. C.; Sancaktar, E.

    1983-01-01

    A general method for characterizing structural adhesives in the bonded lap shear mode is proposed. Two approaches in the form of semi-empirical and theoretical approaches are used. The semi-empirical approach includes Ludwik's and Zhurkov's equations to describe respectively, the failure stresses in the constant strain rate and constant stress loading modes with the inclusion of the temperature effects. The theoretical approach is used to describe adhesive shear stress-strain behavior with the use of viscoelastic or nonlinear elastic constitutive equations. Three different model adhesives are used in the simple lap shear mode with titanium adherends. These adhesives (one of which was developed at NASA Langley Research Center) are currently considered by NASA for possible aerospace applications. Use of different model adhesives helps in assessment of the generality of the method.

  3. Effect of Base and Inlay Restorative Material on the Stress Distribution and Fracture Resistance of Weakened Premolars.

    PubMed

    Souza, A C O; Xavier, T A; Platt, J A; Borges, A L S

    2015-01-01

    The purpose of this study was to evaluate the influence of direct base and indirect inlay materials on stress distribution and fracture resistance of endodontically treated premolars with weakened cusps. Forty healthy human premolars were selected; five were left intact as controls (group C+), and the others were subjected to endodontic treatment and removal of buccal and lingual cusp dentin. Five teeth were left as negative controls (group C-). The remaining 30 teeth were divided into two groups according to the direct base material (glass ionomer [GIC] or composite resin [CR]). After base placement, each group was subjected to extensive inlay preparation, and then three subgroups were created (n=5): no inlay restoration (GIC and CR), restored with an indirect composite resin inlay (GIC+IR and CR+IR), and restored with a ceramic inlay (GIC+C and CR+C). Each specimen was loaded until fracture in a universal testing machine. For finite element analysis, the results showed that the removal of tooth structure significantly affected fracture resistance. The lowest values were presented by the negative control group, followed by the restored and based groups (not statistically different from each other) and all lower than the positive control group. In finite element analysis, the stress concentration was lower in the restored tooth compared to the tooth without restoration, whereas in the restored teeth, the stress concentration was similar, regardless of the material used for the base or restoration. It can be concluded that the inlay materials combined with a base showed similar behavior and were not able to regain the strength of intact tooth structure. PMID:25764042

  4. Adhesion of nickel-titanium shape memory alloy wires to thermoplastic materials: theory and experiments

    NASA Astrophysics Data System (ADS)

    Antico, F. C.; Zavattieri, P. D.; Hector, L. G., Jr.; Mance, A.; Rodgers, W. R.; Okonski, D. A.

    2012-03-01

    We present a combined experimental/theoretical study aimed at enhancing adhesion between a NiTi wire and a thermoplastic polyolefin (TPO) matrix in which it is embedded. NiTi wire surfaces were subjected to the following surface treatments prior to pull-out tests: (i) treatment with an acid etch or chemical conversion coating and (ii) application of a surface microgeometry to enhance mechanical interlocking between the wire and the TPO matrix. Nanometer to micron-scale NiTi wire surface features were examined with atomic force microscopy. The extent to which each treatment increased the pull-out force was quantified. Existing theoretical models of wire pull-out based upon strength of materials and linear elastic fracture mechanics are reviewed. Results from a finite element model (FEM), wherein the NiTi/TPO matrix interface is modeled with a cohesive zone model, suggest that the interface behavior strongly depends on the cohesive energy. The FEM model properly accounts for energy dissipation at the debonding front and inelastic deformation in a NiTi wire during pull-out. We demonstrate that residual stresses from the molding process significantly influence mode mixity at the debonding front.

  5. A Comparative Evaluation of Marginal Leakage of Different Restorative Materials in Deciduous Molars: An in vitro Study

    PubMed Central

    Rehani, Usha; Rana, Vivek

    2012-01-01

    ABSTRACT Context: Microleakage around dental restorative materials is a major problem in clinical dentistry. Inspite of many new restorative materials available in the market very few actually bond to the tooth surface. Aims: The aims of this study were: (1) To evaluate and compare the marginal leakage of newer restorative materials viz colored compomer, ormocer, giomer and RMGIC in class I restoration of deciduous molars. (2) To compare the microleakage scores between the groups of: Colored compomer and ormocer, giomer and RMGIC, ormocer with giomer and RMGIC, giomer with RMGIC. Materials and methods: A total of 40 primary molars were randomly divided into four groups of 10 each. Class I cavities were prepared and the cavities were restored with colored compomer (Group A), Ormocer (Group B), Giomer (Group C) and RMGIC (Group D). The teeth were thermocycled and subjected to 0.5% basic fuchsin dye penetration followed by sectioning. The cut sections were evaluated under a stereomicroscope and the data was subjected to statistical analysis. Statistical analysis used: Mann-Whitney U test and Student t-test. Results: No significant difference was observed when colored compomer was compared to ormocer, giomer and RMGIC. Ormocer showed significantly lower microleakage when compared to giomer. However, no significant difference was observed when ormocer was compared to RMGIC. No significant difference between giomer and RMGIC was found. Conclusion: Ormocer has proven to be an excellent restorative material as it showed least microleakage followed by colored compomer, giomer and RMGIC in increasing order. How to cite this article: Yadav G, Rehani U, Rana V. A Comparative Evaluation of Marginal Leakage of Different Restorative Materials in Deciduous Molars: An in vitro Study . Int J Clin Pediatr Dent 2012;5(2):101-107. PMID:25206147

  6. Evaluation of Microleakage and Marginal Ridge Fracture Resistance of Primary Molars Restored with Three Restorative Materials: A Comparative in vitro Study

    PubMed Central

    Yeolekar, Tapan Satish; Mukunda, KS; Kiran, NK

    2015-01-01

    ABSTRACT Composite restorations are popular because of their superior esthetics and acceptable clinical performance. But shrinkage is still a drawback. Polymerization shrinkage results in volumetric contraction, leading to deformation of the cusps, microleakage, decrease of marginal adaptation, enamel micro-cracks and postoperative sensitivity. A new class of ring opening resin composite based on silorane chemistry has been introduced with claims of less than 1% shrinkage during polymerization. The present study was conducted to evaluate and compare the ability of low shrink silorane based material, a packable composite and a compomer to resist microleakage in class II restorations on primary molars and evaluate marginal ridge fracture resistance of these materials. Sixty human primary molars were selected. Class II cavities were prepared and the teeth were divided into three groups of twenty each. Groups were as follows group I: low shrink composite resin (Filtek P90). Group II: packable composite (Filtek P60) and Group III: compomer (Compoglass F). Half of the teeth were used for microleakage and the rest for marginal ridge fracture resistance. For microleakage testing, dye penetration method was used with 1% methylene blue dye. Followed by evaluation and grading under stereomicroscope at 10* magnification. Fracture resistance was tested with universal testing machine. It was concluded that low shrink silorane based composite resin showed the least amount of microleakage, whereas compomer showed the highest microleakage. Packable composite resisted fracture of marginal ridge better than other composite resins. Marginal ridge fracture resistance of packable composite was comparable to the intact side. How to cite this article: Yeolekar TS, Chowdhary NR, Mukunda KS, Kiran NK. Evaluation of Microleakage and Marginal Ridge Fracture Resistance of Primary Molars Restored with Three Restorative Materials: A Comparative in vitro Study. Int J Clin Pediatr Dent 2015

  7. Dependence of the initial adhesion of biofilm forming Pseudomonas putida mt2 on physico-chemical material properties.

    PubMed

    Montag, Dominik; Frant, Marion; Horn, Harald; Liefeith, Klaus

    2012-01-01

    Bacterial adhesion is strongly dependent on the physico-chemical properties of materials and plays a fundamental role in the development of a growing biofilm. Selected materials were characterized with respect to their physico-chemical surface properties. The different materials, glass and several polymer foils, showed a stepwise range of surface tensions (γ(s)) between 10.3 and 44.7 mN m(-1). Measured zeta potential values were in the range between -74.8 and -28.3 mV. The initial bacterial adhesion parameter q(max) was found to vary between 6.6 × 10(6) and 28.1 × 10(6) cm(-2). By correlation of the initial adhesions kinetic parameters with the surface tension data, the optimal conditions for the immobilization of Pseudomonas putida mt2 were found to be at a surface tension of 24.7 mN m(-1). Both higher and lower surface tensions lead to a smaller number of adherent cells per unit surface area. Higher energy surfaces, commonly termed hydrophilic, could constrain bacterial adhesion because of their more highly ordered water structure (exclusion zone) close to the surface. At low energy surfaces, commonly referred to as hydrophobic, cell adhesion is inhibited due to a thin, less dense zone (depletion layer or clathrate structure) close to the surface. Correlation of q (max) with zeta potential results in a linear relationship. Since P. putida carries weak negative charges, a measurable repulsive effect can be assumed on negative surfaces. PMID:22452391

  8. Comparative study of mechanical properties of dental restorative materials and dental hard tissues in compressive loads.

    PubMed

    Chun, Keyoung Jin; Lee, Jong Yeop

    2014-01-01

    There are two objectives. One is to show the differences in the mechanical properties of various dental restorative materials compared to those of enamel and dentin. The other is to ascertain which dental restorative materials are more suitable for clinical treatments. Amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were processed as dental restorative material specimens. The specimens (width, height, and length of 1.2, 1.2, and 3.0 mm, respectively) were compressed at a constant loading speed of 0.1 mm/min. The maximum stress (115.0 ± 40.6, 55.0 ± 24.8, 291.2 ± 45.3, 274.6 ± 52.2, 2206.0 ± 522.9, and 953.4 ± 132.1 MPa), maximum strain (7.8% ± 0.5%, 4.0% ± 0.1%, 12.7% ± 0.8%, 32.8% ± 0.5%, 63.5% ± 14.0%, and 45.3% ± 7.4%), and elastic modulus (1437.5 ± 507.2, 1548.4 ± 583.5, 2323.4 ± 322.4, 833.1 ± 92.4, 3895.2 ± 202.9, and 2222.7 ± 277.6 MPa) were evident for amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy, respectively. The reference hardness value of amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy was 90, 420, 130-135, 86.6-124.2, 1250, and 349, respectively. Since enamel grinds food, its abrasion resistance is important. Therefore, hardness value should be prioritized for enamel. Since dentin absorbs bite forces, mechanical properties should be prioritized for dentin. The results suggest that gold alloy simultaneously has a hardness value lower than enamel (74.8 ± 18.1), which is important in the wear of the opposing natural teeth, and higher maximum stress, maximum strain, and elastic modulus than dentin (193.7 ± 30.6 MPa, 11.9% ± 0.1%, 1653.7 ± 277.9 MPa, respectively), which are important considering the rigidity to absorb bite forces. PMID:25352921

  9. Comparative study of mechanical properties of dental restorative materials and dental hard tissues in compressive loads

    PubMed Central

    Lee, Jong Yeop

    2014-01-01

    There are two objectives. One is to show the differences in the mechanical properties of various dental restorative materials compared to those of enamel and dentin. The other is to ascertain which dental restorative materials are more suitable for clinical treatments. Amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy were processed as dental restorative material specimens. The specimens (width, height, and length of 1.2, 1.2, and 3.0 mm, respectively) were compressed at a constant loading speed of 0.1 mm/min. The maximum stress (115.0 ± 40.6, 55.0 ± 24.8, 291.2 ± 45.3, 274.6 ± 52.2, 2206.0 ± 522.9, and 953.4 ± 132.1 MPa), maximum strain (7.8% ± 0.5%, 4.0% ± 0.1%, 12.7% ± 0.8%, 32.8% ± 0.5%, 63.5% ± 14.0%, and 45.3% ± 7.4%), and elastic modulus (1437.5 ± 507.2, 1548.4 ± 583.5, 2323.4 ± 322.4, 833.1 ± 92.4, 3895.2 ± 202.9, and 2222.7 ± 277.6 MPa) were evident for amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy, respectively. The reference hardness value of amalgam, dental ceramic, gold alloy, dental resin, zirconia, and titanium alloy was 90, 420, 130–135, 86.6–124.2, 1250, and 349, respectively. Since enamel grinds food, its abrasion resistance is important. Therefore, hardness value should be prioritized for enamel. Since dentin absorbs bite forces, mechanical properties should be prioritized for dentin. The results suggest that gold alloy simultaneously has a hardness value lower than enamel (74.8 ± 18.1), which is important in the wear of the opposing natural teeth, and higher maximum stress, maximum strain, and elastic modulus than dentin (193.7 ± 30.6 MPa, 11.9% ± 0.1%, 1653.7 ± 277.9 MPa, respectively), which are important considering the rigidity to absorb bite forces. PMID:25352921

  10. Influence of artificially accelerated ageing on the adhesive joint of plasma treated polymer materials

    NASA Astrophysics Data System (ADS)

    Lehocký, M.; Lapčik, L.; Dlabaja, R.; Rachünek, L.; Stoch, J.

    2004-03-01

    An influence of simulated ageing on the adhesive joint of plasma treated polyethylene (PE) and polypropylene (PP) was tested. Plasma surface treatment was performed in the rf-plasma reactor operating at 13,56 MHz. The simulated ageing of prepared specimens for following tensile testing was carried out under conditions given by Volkswagen standard P-VW 1200. Temperature of ageing was regularly oscillating between -40°C and 80°C (relative humidity 80%) for required time. The mechanical tensile properties of adhesive joint were measured according to the standard ISO 527. Surface analysis of treated polymer substrates was characterized by XPS measurement. The observation of surface structure and morphology was obtained using SEM. We used convenient cyanoacrylate adhesive Loctite E 406 for PE and PP joints. Tested adhesive joints were prepared in compliance with the standard ISO 4587.

  11. Laboratory evaluation of adhesive systems.

    PubMed

    Barkmeier, W W; Cooley, R L

    1992-01-01

    Adhesive bonding of resin materials to acid-conditioned enamel is a clinically proven technique in preventative, restorative, and orthodontic procedures. Laboratory evaluations of etched-enamel resin bonding have shown excellent bond strengths and the virtual elimination of marginal microleakage. Adhesion to dentin has been more of a challenge. Earlier-generation dentin bonding systems did not yield high bond strengths in the laboratory or prevent marginal microleakage. Newer-generation adhesive systems generally use a dentin conditioner to modify or remove the smear layer and a subsequent application of an adhesive resin bonding agent. Laboratory evaluations of newer systems have shown bond strengths that approach or actually exceed that of etched enamel resin bonding. Bond strengths have improved with the evolution of dentin bonding systems, and microleakage from the cementum/dentin margin has been significantly reduced or prevented with the newer systems. Although laboratory testing of adhesive systems provides a mechanism to screen and compare newly developed systems, clinical trials are essential to document long-term clinical performance. PMID:1470553

  12. Characteristics of pristine volcanic materials: Beneficial and harmful effects and their management for restoration of agroecosystem.

    PubMed

    Anda, Markus; Suparto; Sukarman

    2016-02-01

    Eruption of Sinabung volcano in Indonesia began again in 2010 after resting for 1200 years. The volcano is daily emitting ash and pyroclastic materials since September 2013 to the present, damaging agroecosystems and costing for management restoration. The objective of the study was to assess properties and impacts of pristine volcanic material depositions on soil properties and to provide management options for restoring the affected agroecosytem. Land satellite imagery was used for field studies to observe the distribution, thickness and properties of ashfall deposition. The pristine ashfall deposits and the underlying soils were sampled for mineralogical, soluble salt, chemical, physical and toxic compound analyses. Results showed that uneven distribution of rainfall at the time of violent eruption caused the areas receiving mud ashfall developed surface encrustation, which was not occur in areas receiving dry ashfall. Ashfall damaged the agroecosytem by burning vegetation, forming surface crusts, and creating soil acidity and toxicity. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses of encrustated layer indicated the presence of gypsum and jarosite minerals. Gypsum likely acted as a cementing agent in the formation of the encrustation layer with extremely low pH (2.9) and extremely high concentrations of Al, Ca and S. Encrustation is responsible for limited water infiltration and root penetration, while the extremely high concentration of Al is responsible for crop toxicity. Mud ashfall and dry ashfall deposits also greatly changed the underlying soil properties by decreasing soil pH and cation exchange capacity and by increasing exchangeable Ca, Al, and S availability. Despite damaging vegetation in the short-term, the volcanic ashfall enriched the soil in the longer term by adding nutrients like Ca, Mg, K, Na, P, Si and S. Suggested management practices to help restore the agroecosystem after volcanic eruptions include: (i) the

  13. CHIPPING FRACTURE RESISTANCE OF DENTAL CAD/CAM RESTORATIVE MATERIALS: PART I, PROCEDURES AND RESULTS

    PubMed Central

    Quinn, G. D.; Giuseppetti, A. A.; Hoffman, K. H.

    2014-01-01

    Objective The edge chipping test was used to measure the fracture resistance of CAD/CAM dental restoration ceramics and resin composites. Methods An edge chipping machine was used to evaluate six materials including one feldspathic porcelain, two glass ceramics, a filled resin-composite, a yttria-stabilized zirconia, and a new ceramic-resin composite material. Force versus edge distance data were collected over a broad range of forces and distances. Data were analyzed by several approaches and several chipping resistance parameters were evaluated. The effects of using different indenter types were explored. Results The force versus distance trends were usually nonlinear with good fits to a power law equation with exponents usually ranging from 1.2 to 1.9. The order of chipping resistance (from least to greatest) was: feldspathic porcelain and a leucite glass ceramic (which were similar), followed by the lithium disilicate glass ceramic and the two resin composites (which were similar), and finally the zirconia which had the greatest resistance to chipping. Chipping with a Vickers indenter required 28% to 45% more force than with the sharp conical 120° indenter. The two indenters rank materials approximately the same way. The power law exponents were very similar for the two indenters for a particular material, but the exponents varied with material. The Rockwell C indenter gives different power law trends and rankings. Significance Despite the variations in the trends and indenters, simple comparisons between materials can be made by chipping with sharp conical 120° or Vickers indenters at 0.50 mm. Broad distance ranges are recommended for trend evaluation. PMID:24685178

  14. Fabrication of interdigitated micropatterns of self-assembled polymer nanofilms containing cell-adhesive materials.

    PubMed

    Shaikh Mohammed, Javeed; Decoster, Mark A; McShane, Michael J

    2006-03-14

    Micropatterns of different biomaterials with micro- and nanoscale features and defined spatial arrangement on a single substrate are useful tools for studying cellular-level interactions, and recent reports have highlighted the strong influence of scaffold compliance in determining cell behavior. In this paper, a simple yet versatile and precise patterning technique for the fabrication of interdigitated micropatterns of nanocomposite multilayer coatings on a single substrate is demonstrated through a combination of lithography and layer-by-layer (LbL) assembly processes, termed polymer surface micromachining (PSM). The first nanofilm pattern is constructed using lithography, followed by LbL multilayer assembly and lift-off, and the process is repeated with optical alignment to obtain interdigitated patterns on the same substrate. Thus, the method is analogous to surface micromachining, except that the deposition materials are polymers and biological materials that are used to produce multilayer nanocomposite structures. A key feature of the multilayers is the capability to tune properties such as stiffness by appropriate selection of materials, deposition conditions, and postdeposition treatments. Two- and four-component systems on glass coverslips are presented to demonstrate the versatility of the approach to construct precisely defined, homogeneous nanofilm patterns. In addition, an example of a complex system used as a testbed for in vitro cell adhesion and growth is provided: micropatterns of poly(sodium 4-styrenesulfonate)/poly-L-lysine hydrobromide (PSS/PLL) and secreted phospholipase A(2)/poly(ethyleneimine) (sPLA(2)/PEI) multilayers. The interdigitated square nanofilm array patterns were obtained on a single coverslip with poly(diallyldimethylammonium chloride) (PDDA) as a cell-repellent background. Cell culture experiments show that cortical neurons respond and bind specifically to the sPLA(2) micropatterns in competition with PLL micropatterns. The

  15. Understanding Marine Mussel Adhesion

    SciTech Connect

    H. G. Silverman; F. F. Roberto

    2007-12-01

    In addition to identifying the proteins that have a role in underwater adhesion by marine mussels, research efforts have focused on identifying the genes responsible for the adhesive proteins, environmental factors that may influence protein production, and strategies for producing natural adhesives similar to the native mussel adhesive proteins. The production-scale availability of recombinant mussel adhesive proteins will enable researchers to formulate adhesives that are waterimpervious and ecologically safe and can bind materials ranging from glass, plastics, metals, and wood to materials, such as bone or teeth, biological organisms, and other chemicals or molecules. Unfortunately, as of yet scientists have been unable to duplicate the processes that marine mussels use to create adhesive structures. This study provides a background on adhesive proteins identified in the blue mussel, Mytilus edulis, and introduces our research interests and discusses the future for continued research related to mussel adhesion.

  16. Understanding marine mussel adhesion.

    PubMed

    Silverman, Heather G; Roberto, Francisco F

    2007-01-01

    In addition to identifying the proteins that have a role in underwater adhesion by marine mussels, research efforts have focused on identifying the genes responsible for the adhesive proteins, environmental factors that may influence protein production, and strategies for producing natural adhesives similar to the native mussel adhesive proteins. The production-scale availability of recombinant mussel adhesive proteins will enable researchers to formulate adhesives that are water-impervious and ecologically safe and can bind materials ranging from glass, plastics, metals, and wood to materials, such as bone or teeth, biological organisms, and other chemicals or molecules. Unfortunately, as of yet scientists have been unable to duplicate the processes that marine mussels use to create adhesive structures. This study provides a background on adhesive proteins identified in the blue mussel, Mytilus edulis, and introduces our research interests and discusses the future for continued research related to mussel adhesion. PMID:17990038

  17. Understanding Marine Mussel Adhesion

    PubMed Central

    Roberto, Francisco F.

    2007-01-01

    In addition to identifying the proteins that have a role in underwater adhesion by marine mussels, research efforts have focused on identifying the genes responsible for the adhesive proteins, environmental factors that may influence protein production, and strategies for producing natural adhesives similar to the native mussel adhesive proteins. The production-scale availability of recombinant mussel adhesive proteins will enable researchers to formulate adhesives that are water-impervious and ecologically safe and can bind materials ranging from glass, plastics, metals, and wood to materials, such as bone or teeth, biological organisms, and other chemicals or molecules. Unfortunately, as of yet scientists have been unable to duplicate the processes that marine mussels use to create adhesive structures. This study provides a background on adhesive proteins identified in the blue mussel, Mytilus edulis, and introduces our research interests and discusses the future for continued research related to mussel adhesion. PMID:17990038

  18. Effective dentin restorative material based on phosphate-terminated dendrimer as artificial protein.

    PubMed

    Zhang, Hui; Yang, Jiaojiao; Liang, Kunneng; Li, Jiyao; He, Libang; Yang, Xiao; Peng, Shuangjuan; Chen, Xingyu; Ding, Chunmei; Li, Jianshu

    2015-04-01

    In clinic, it calls for effective and simple materials to repair etched dentin. Bioinspired by the natural mineralization process guided by noncollagenous proteins (NCPs), in this work, we synthesized the fourth generation phosphate-terminated polyamidoamine dendrimer (G4-PO3H2) by one-step modification. We used FT-IR and 1H NMR to characterize the structure of G4-PO3H2, and MTT assay to prove its biocompatibility. It was applied as the analog of dentin phosphophoryn (DPP: a type of NCPs) to repair dentin, due to its similar dimensional scale, topological architecture and peripheral functionalities to that of DPP. By the characterization of SEM and XRD, the effective regeneration of human dentin induced by G4-PO3H2 is characterized and illustrated both in vitro (artificial saliva) and in vivo (oral cavity of rats). It is noted that the thickness of the regenerated mineral layers are more than 10 μm both in vitro and in vivo. The design strategy of G4-PO3H2 may be valuable for researchers in the fields of material science, stomatology and medicine to prepare various promising restorative nano-materials for biomineralized hard tissues such as bone and teeth. PMID:25703791

  19. Antibacterial effects of hybrid tooth colored restorative materials against Streptococcus mutans: An in vitro analysis

    PubMed Central

    Hotwani, Kavita; Thosar, Nilima; Baliga, Sudhindra; Bundale, Sunita; Sharma, Krishna

    2013-01-01

    Objective: The objective of this study was to evaluate the antibacterial effect of two hybrid restoratives, namely resin modified glass ionomer cement (GC Fuji II™ LC, GC Corporation, Tokyo, Japan) and giomer (Beautifil-II, Shofu Inc., Kyoto, Japan) against Streptococcus mutans [Microbial Type Culture Collection (MTCC), 890]. Materials and Methods: The antibacterial effect was evaluated using an agar diffusion test. The prepared wells in petri dishes were completely filled with chlorhexidine (positive control group), resin modified glass ionomer cement and giomer respectively. Prepared bacterial suspension was poured over the petri dish and was spread evenly using the plate spreader. The culture plates were placed in the incubator for 24 h at 37°C. The antibacterial activity was evaluated after 24 h, 48 h, and 7 days for each group in triplicates. Results and Conclusion: The results of the antibacterial effect of the tested materials were collected, statistically analyzed using the ANOVA test to determine the difference between the mean diameters of the inhibition zone produced. The mean zone of bacterial inhibition was found to be more with the giomer specimens at all time periods. However, this inhibitory activity showed a gradual decrease over a period of 7 days and the maximum inhibition was evident after 24 h with both the test materials. PMID:23956533

  20. Ormocer: An aesthetic direct restorative material; An in vitro study comparing the marginal sealing ability of organically modified ceramics and a hybrid composite using an ormocer-based bonding agent and a conventional fifth-generation bonding agent

    PubMed Central

    Kalra, Sarika; Singh, Arundeep; Gupta, Manish; Chadha, Vandana

    2012-01-01

    Aims and Objectives: To compare the marginal sealing ability of ormocer with a hybrid composite using an ormocer based bonding agent and a conventional fifth generation bonding agent. Materials and Methods: Fifty four human premolars were randomly distributed into four test groups of 12 teeth each and two control groups of 3 teeth each. Class I occlusal preparation of 1.5 mm depth were made in each tooth. These were restored using the adhesive and restorative material according to the group. The restorations were finished using a standard composite finishing and polishing kit. Thermocycling between 5° C and 55°C was carried out. Having blocked the root apex and the entire tooth surface except 1 mm around the restoration margin, the teeth were immersed in 2% methylene blue for 48 hours, after which the dye penetration through the margins of each sample was studied under a stereomicroscope. Results and Discussion: Group IV (Admira with Admira Bond) showed the minimum marginal leakage with a mean of 0.200 mm. Four samples in this group showed no microleakage at all and a maximum of 0.400 mm was seen in one sample. Group II (Spectrum TPH with Admira Bond) showed the maximum leakage with a mean of 0.433 mm. One sample showed as much as 1.00 mm of microleakage. Admira when used with Admira Bond showed lesser microleakage than Spectrum TPH used with Prime & Bond NT, the difference being statistically insignificant. PMID:22557897

  1. [Clinical and laboratory studies of bacterial adhesion to validate the choice of material for making provisional dentures for patients with periodontal diseases].

    PubMed

    Ibragimov, T I; Arutiunov, S D; Tsarev, V N; Lebedenko, I Iu; Kraveishvili, S E; Trefilov, A G; Arutiunov, D S; Lomakina, N A

    2002-01-01

    Adhesion of bacteria favoring the development of oral inflammations, including cariesogenic and periodontopathogenic (Actinobacillus actinomycetemcommitans, Streptococcus sanguis, Fusobacterium nucleatum, Staphylococcus warneri) and yeast fungi (Candida albicans), to 13 materials used for making provisional dentures was studied. Adhesion of all the studied bacteria and fungi to Russian material Esterfil Foto was the minimum. Clinical use of this material in patients with chronic generalized periodontitis showed that it was well tolerated and the treatment led to improvement of oral microbiocenosis. PMID:12056141

  2. Open Photoacoustic Cell Technique as a Tool for Thermal and Thermo-Mechanical Characterization of Teeth and Their Restorative Materials

    NASA Astrophysics Data System (ADS)

    Pichardo-Molina, J. L.; Gutiérrez-Juárez, G.; Huerta-Franco, R.; Vargas-Luna, M.; Cholico, P.; Alvarado-Gil, J. J.

    2005-01-01

    The thermal diffusivity and thermal expansion coefficient of teeth and three of their most common restorative materials (Amalgam Phase Alloy, Ionomer Fuji II LC, and Resin 3MFPITEK Lutine TMZ250) were studied by means of the open photoacoustic technique. These results were then used as a basis for the theoretical simulation of the photothermal process taking place as a consequence of modulated illumination of a two-layer system formed by the tooth and the restorative material. The model accounts for the coupling of thermal waves and thermoelastic vibration in the two-layer system.

  3. An evaluation of microleakage of various glass ionomer based restorative materials in deciduous and permanent teeth: An in vitro study

    PubMed Central

    Singla, Teena; Pandit, I.K.; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika

    2011-01-01

    Aim To evaluate the microleakage of recently available glass ionomer based restorative materials (GC Fuji IX GP, GC Fuji VII, and Dyract) and compare their microleakage with the previously existing glass ionomer restorative materials (GC Fuji II LC) in primary and permanent teeth. Method One hundred and fifty (75 + 75) non-carious deciduous and permanent teeth were restored with glass ionomer based restorative materials after making class I cavities. Samples were subjected to thermocycling after storing in distilled water for 24 h. Two coats of nail polish were applied 1 mm short of restorative margins and samples sectioned buccolingually after storing in methylene blue dye for 24 h. Microleakage was assessed using stereomicroscope. Result Significant differences (P < 0.05) were found when inter group comparisons were done. Except when GC Fuji VII (Group III) was compared with GC Fuji II LC (Group II) and Dyract (Group IV), non-significant differences (P > 0.05) were observed. It was found that there was no statistically significant difference when the means of microleakage of primary teeth were compared with those of permanent teeth. Conclusions GC Fuji IX GP showed maximum microleakage and GC Fuji VII showed least microleakage. PMID:23960526

  4. Influence of Cavity Preparation with Er,Cr:YSGG Laser and Restorative Materials on In Situ Secondary Caries Development

    PubMed Central

    Jorge, Ana Carolina Tedesco; Cassoni, Alessandra; de Freitas, Patrícia Moreira; Reis, André Figueiredo; Junior, Aldo Brugnera

    2015-01-01

    Abstract Objective: The aim of this study was to evaluate the influence of cavity preparation and restorative materials containing fluorides in the prevention of secondary caries lesion development in situ. Methods: A total of 120 blocks obtained from human teeth were divided into two groups and standardized cavities were prepared using diamond burs (DB) or Er,Cr:YSGG-laser [20 Hz, 4.0W, 55% water, 65% air (LA)]. They were divided into three subgroups according to the restorative material (n=20): glass-ionomer cement (GI), resin modified glass-ionomer (RM) or composite resin (CR). Blocks were fixed in palatal intra-oral appliances worn in situ by 20 human volunteers, who dropped 20% sucrose solution eight times daily. After 21 days, blocks were removed and restorations were cross-sectioned to evaluate microhardness [Knoop hardness number (KHN)] underneath enamel surface from 30 to 200 μm. Factors “cavity preparation,” “restorative materials,” and “depth” were evaluated by three way ANOVA, followed by Tukey test (p<0.05). Results: The results showed lower microhardness in cavities prepared with DB than in cavities prepared with LA. At 30 μm, there were no statistical significant differences with regard to “cavity preparation” or “restorative materials” factors. In depth evaluation, the enamel microhardness progressively increased as a function of depth for the GI groups. In the groups prepared with LA at 60 μm/90 μm, there were no significant differences between GI and RM materials, whose microhardnesses were significantly higher than that of CR. Conclusions: Cavity preparation using Er,Cr:YSGG laser increases caries resistance of enamel walls, and reduce caries lesion depth development regardless of fluoride presence in the restorative material. CR showed higher caries lesion development than GI, and RM showed intermediate results. PMID:25654424

  5. Bioactivity studies and adhesion of human osteoblast (hFOB) on silicon-biphasic calcium phosphate material.

    PubMed

    Ibrahim, S; Sabudin, S; Sahid, S; Marzuke, M A; Hussin, Z H; Kader Bashah, N S; Jamuna-Thevi, K

    2016-01-01

    Surface reactivity of bioactive ceramics contributes in accelerating bone healing by anchoring osteoblast cells and the connection of the surrounding bone tissues. The presence of silicon (Si) in many biocompatible and bioactive materials has been shown to improve osteoblast cell adhesion, proliferation and bone regeneration due to its role in the mineralisation process around implants. In this study, the effects of Si-biphasic calcium phosphate (Si-BCP) on bioactivity and adhesion of human osteoblast (hFOB) as an in vitro model have been investigated. Si-BCP was synthesised using calcium hydroxide (Ca(OH)2) and phosphoric acid (H3PO4) via wet synthesis technique at Ca/P ratio 1.60 of material precursors. SiO2 at 3 wt% based on total precursors was added into apatite slurry before proceeding with the spray drying process. Apatite powder derived from the spray drying process was pressed into discs with Ø 10 mm. Finally, the discs were sintered at atmospheric condition to obtain biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) peaks simultaneously and examined by XRD, AFM and SEM for its bioactivity evaluation. In vitro cell viability of L929 fibroblast and adhesion of hFOB cell were investigated via AlamarBlue® (AB) assay and SEM respectively. All results were compared with BCP without Si substitution. Results showed that the presence of Si affected the material's surface and morphology, cell proliferation and cell adhesion. AFM and SEM of Si-BCP revealed a rougher surface compared to BCP. Bioactivity in simulated body fluid (SBF) was characterised by pH, weight gain and apatite mineralisation on the sample surface whereby the changes in surface morphology were evaluated using SEM. Immersion in SBF up to 21 days indicated significant changes in pH, weight gain and apatite formation. Cell viability has demonstrated no cytotoxic effect and denoted that Si-BCP promoted good initial cell adhesion and proliferation. These results suggest that Si

  6. Adhesive curing options for photonic packaging

    NASA Astrophysics Data System (ADS)

    Martin, Steven C.; Hubert, Manfred; Tam, Robin

    2002-06-01

    Varying the intensity of illumination used to cure photoactivated adhesives has been applied in medical and dental applications to improve the performance of polymer materials. For example, it has been observed that dental polymer composite materials express reduced shrinkage, important for durability of non-amalgam restorations, by introducing a phased time-intensity cure schedule. This work identified that curing conditions could influence the final properties of materials, and suggested the possibility of extending the characteristics that could be influenced beyond shrinkage to humidity resistance, Tg, outgassing and other important material properties. Obviously, these results have important ramifications for the photonic industry, with current efforts focused on improved manufacturing techniques. Improvement in low cost packaging solutions, including adhesives, will have to be made to bring the component cost down to address the needs of Metro and similar markets. However, there are perceived problems with the widespread use of adhesives, the most prevalent of these involving long term durability of the bond. Devices are typically aligned to sub-micron precision using active feedback and then must be locked in position to maintain performance. In contrast to traditional fastening methods, adhesive bonding is a highly attractive option due to the ease of deployment, lower equipment costs, and improved flexibility. Moreover, using methods analogous to those employed in dental applications, materials properties of photonic adhesives may be tailored using a programmed cure approach.

  7. Dentin bonding performance and interface observation of an MMA-based restorative material.

    PubMed

    Shinagawa, Junichi; Inoue, Go; Nikaido, Toru; Ikeda, Masaomi; Sadr, Alireza; Tagami, Junji

    2016-07-30

    The purpose of this study was to evaluate bonding performance and dentin interface acid resistance using a 4-META/MMA-TBB based restorative material (BF) compared to a conventional 4-META/MMA-TBB resin cement (SB), and the effect of sodium fluoride (NaF) addition to the materials. Dentin surfaces were treated with 10% citric acid-3% ferric chloride (10-3) or 4-META containing self-etching primer (TP), followed by application of BF or SB polymer powders with or without NaF, to evaluate microtensile bond strength (µTBS) in six experimental groups; 10-3/SB, 10-3/BF, TP/SB, TP/BF, TP/SB/NaF and TP/BF/NaF. SEM observation of the resin-dentin interface was performed after acid-base challenge to evaluate interfacial dentin resistance to acid attack. TP/BF showed highest µTBS, while NaF polymers decreased µTBS. TP/BF showed funnel-shaped erosion at the interface, however, NaF polymers improved acid resistance of interface. In conclusion, BF demonstrated high µTBSs and low acid-resistance at the interface. NaF addition enhanced acid resistance but decreased µTBS. PMID:27335135

  8. Weight change of various light-cured restorative materials after water immersion.

    PubMed

    Iwami, Y; Yamamoto, H; Sato, W; Kawai, K; Torii, M; Ebisu, S

    1998-01-01

    This study investigated weight changes of various light-cured glass-ionomer cements and other restorative materials during water immersion and compared findings with those of conventional glass-ionomer cement and light-cured resin composites. Three light-cured glass-ionomer cements, two polyacid-modified composite resins, one conventional glass-ionomer cement, and one light-cured composite resin were evaluated in this study. The weight changes of these specimens after water immersion were measured using an electronic analytical balance and adjusted according to water solubility measured at the same time weight change was measured. The results were analyzed by one-way ANOVA and Scheffé's F test at P < 0.05. The weight change of Photac-Fil Aplicap was the largest, and there were significant differences among the materials (P < 0.05). Weight change after 6 weeks' water immersion was noted in the following order: Fuji Ionomer Type II LC, Vitremer, Fuji Ionomer Type II, VariGlass VLC, Geristore V, and Clearfil AP-X. It is suggested that the amount of water sorption of light-cured glass-ionomer cements is greater than that of polyacid-modified composite resins. PMID:9656924

  9. Elastomer toughened polyimide adhesives. [bonding metal and composite material structures for aircraft and spacecraft

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; St.clair, T. L. (Inventor)

    1985-01-01

    A rubber-toughened, addition-type polyimide composition is disclosed which has excellent high temperature bonding characteristics in the fully cured state and improved peel strength and adhesive fracture resistance physical property characteristics. The process for making the improved adhesive involves preparing the rubber-containing amic acid prepolymer by chemically reacting an amine-terminated elastomer and an aromatic diamine with an aromatic dianhydride with which a reactive chain stopper anhydride has been mixed, and utilizing solvent or mixture of solvents for the reaction.

  10. Bioactivity studies and adhesion of human osteoblast (hFOB) on silicon-biphasic calcium phosphate material

    PubMed Central

    Ibrahim, S.; Sabudin, S.; Sahid, S.; Marzuke, M.A.; Hussin, Z.H.; Kader Bashah, N.S.; Jamuna-Thevi, K.

    2015-01-01

    Surface reactivity of bioactive ceramics contributes in accelerating bone healing by anchoring osteoblast cells and the connection of the surrounding bone tissues. The presence of silicon (Si) in many biocompatible and bioactive materials has been shown to improve osteoblast cell adhesion, proliferation and bone regeneration due to its role in the mineralisation process around implants. In this study, the effects of Si-biphasic calcium phosphate (Si-BCP) on bioactivity and adhesion of human osteoblast (hFOB) as an in vitro model have been investigated. Si-BCP was synthesised using calcium hydroxide (Ca(OH)2) and phosphoric acid (H3PO4) via wet synthesis technique at Ca/P ratio 1.60 of material precursors. SiO2 at 3 wt% based on total precursors was added into apatite slurry before proceeding with the spray drying process. Apatite powder derived from the spray drying process was pressed into discs with Ø 10 mm. Finally, the discs were sintered at atmospheric condition to obtain biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) peaks simultaneously and examined by XRD, AFM and SEM for its bioactivity evaluation. In vitro cell viability of L929 fibroblast and adhesion of hFOB cell were investigated via AlamarBlue® (AB) assay and SEM respectively. All results were compared with BCP without Si substitution. Results showed that the presence of Si affected the material’s surface and morphology, cell proliferation and cell adhesion. AFM and SEM of Si-BCP revealed a rougher surface compared to BCP. Bioactivity in simulated body fluid (SBF) was characterised by pH, weight gain and apatite mineralisation on the sample surface whereby the changes in surface morphology were evaluated using SEM. Immersion in SBF up to 21 days indicated significant changes in pH, weight gain and apatite formation. Cell viability has demonstrated no cytotoxic effect and denoted that Si-BCP promoted good initial cell adhesion and proliferation. These results suggest that Si

  11. Plasma damage and restoration of a spin-on organic ultra low-k material (k=2.3)

    NASA Astrophysics Data System (ADS)

    Lukaszewicz, Mikolaj; de Marneffe, Jean-Francois; Wilson, Christopher J.; Zhang, Liping; Peng, Hsin-Ying; Verdonck, Patrick; Baklanov, Mikhail

    2012-10-01

    As interconnect dielectrics, spin-on polymers might offer some advantages over OSG materials. In particular, a lower k-value is possible with less porosity, smaller pore size. They also have greater resistance to plasma damage due to their mono-component nature. However, some chemical modifications during the plasma exposure cannot be avoided. In this work, we study the changes caused by a N2-H2-C2H4 CCP discharge used for damascene patterning, on a spin-on k=2.3 organic low-k material. It is shown that this plasma forms amine and ester groups, leading to hydrophilization and k-value degradation. Several restoration treatments are studied on blanket wafers, trying to restore the chemical composition, minimize the k-value and hydrophilization. Those treatments include exposure to in-situ He-H2 discharge, high temperature He-H2 afterglow and combinations thereof, low- and high-temperature VUV treatments. It is found that the best k-value gain is around 50%, and the most promising repair treatment results from the short exposure to a combination of low temperature in-situ He-H2 discharge and high temperature He-H2 afterglow. Applying such restoration process to an array of 30nm trenches, the integrated k-value showed a gain of 13% in RC constant, indicating efficient restoration to pristine k-value, although the chemical composition was not completely restored in all evaluated conditions.

  12. Corneal Cell Adhesion to Contact Lens Hydrogel Materials Enhanced via Tear Film Protein Deposition

    PubMed Central

    Elkins, Claire M.; Qi, Qin M.; Fuller, Gerald G.

    2014-01-01

    Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS), borate buffered saline (BBS), or Sensitive Eyes Plus Saline Solution (Sensitive Eyes), either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes) exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo. PMID:25144576

  13. Effect of ultrasound on cyprid footprint and juvenile barnacle adhesion on a fouling release material.

    PubMed

    Guo, Shifeng; Khoo, Boo Cheong; Teo, Serena Lay Ming; Zhong, Shaoping; Lim, Chwee Teck; Lee, Heow Pueh

    2014-03-01

    In our earlier studies, we have demonstrated that low and high intensity ultrasound can prevent barnacle cyprid settlement. In this study, we found that ultrasound treatment reduced the adhesion of newly metamorphosed barnacles up to 2 days' old. This was observed in the reduction of adhesion strength of the newly settled barnacles from ultrasound treated cyprids on silicone substrate compared to the adhesion strength of barnacles metamorphosed from cyprids not exposed to ultrasound. Atomic force microscopy (AFM) was used to analyze the effect of ultrasound on barnacle cyprid footprints (FPs), which are protein adhesives secreted when the larvae explore surfaces. The ultrasound treated cyprids were found to secrete less FPs, which appeared to spread a larger area than those generated by untreated cyprids. The evidence from this study suggests that ultrasound treatment results in a reduced cyprid settlement and footprint secretion, and may affect the subsequent recruitment of barnacles onto fouling release surfaces by reducing the ability of early settlement stage of barnacles (up to 2 days' old) from firmly adhering to the substrates. Ultrasound therefore can be used in combination with fouling release coatings to offer a more efficient antifouling strategy. PMID:24333559

  14. Ultrashort pulse laser processing of hard tissue, dental restoration materials, and biocompatibles

    NASA Astrophysics Data System (ADS)

    Yousif, A.; Strassl, M.; Beer, F.; Verhagen, L.; Wittschier, M.; Wintner, E.

    2007-07-01

    During the last few years, ultra-short laser pulses have proven their potential for application in medical tissue treatment in many ways. In hard tissue ablation, their aptitude for material ablation with negligible collateral damage provides many advantages. Especially teeth representing an anatomically and physiologically very special region with less blood circulation and lower healing rates than other tissues require most careful treatment. Hence, overheating of the pulp and induction of microcracks are some of the most problematic issues in dental preparation. Up till now it was shown by many authors that the application of picosecond or femtosecond pulses allows to perform ablation with very low damaging potential also fitting to the physiological requirements indicated. Beside the short interaction time with the irradiated matter, scanning of the ultra-short pulse trains turned out to be crucial for ablating cavities of the required quality. One main reason for this can be seen in the fact that during scanning the time period between two subsequent pulses incident on the same spot is so much extended that no heat accumulation effects occur and each pulse can be treated as a first one with respect to its local impact. Extension of this advantageous technique to biocompatible materials, i.e. in this case dental restoration materials and titanium plasma-sprayed implants, is just a matter of consequence. Recently published results on composites fit well with earlier data on dental hard tissue. In case of plaque which has to be removed from implants, it turns out that removal of at least the calcified version is harder than tissue removal. Therefore, besides ultra-short lasers, also Diode and Neodymium lasers, in cw and pulsed modes, have been studied with respect to plaque removal and sterilization. The temperature increase during laser exposure has been experimentally evaluated in parallel.

  15. In vitro evaluation of fracture strength of zirconia restoration veneered with various ceramic materials

    PubMed Central

    Choi, Yu-Sung; Lee, Jai-Bong; Han, Jung-Suk; Yeo, In-Sung

    2012-01-01

    PURPOSE Fracture of the veneering material of zirconia restorations frequently occurs in clinical situations. The purpose of this in vitro study was to compare the fracture strengths of zirconia crowns veneered with various ceramic materials by various techniques. MATERIALS AND METHODS A 1.2 mm, 360° chamfer preparation and occlusal reduction of 2 mm were performed on a first mandibular molar, and 45 model dies were fabricated in a titanium alloy by CAD/CAM system. Forty-five zirconia copings were fabricated and divided into three groups. In the first group (LT) zirconia copings were veneered with feldspathic porcelain by the layering technique. In the second group (HT) the glass ceramic was heat-pressed on the zirconia coping, and for the third group (ST) a CAD/CAM-fabricated high-strength anatomically shaped veneering cap was sintered onto the zirconia coping. All crowns were cemented onto their titanium dies with Rely X™ Unicem (3M ESPE) and loaded with a universal testing machine (Instron 5583) until failure. The mean fracture values were compared by an one-way ANOVA and a multiple comparison post-hoc test (α=0.05). Scanning electron microscope was used to investigate the fractured interface. RESULTS Mean fracture load and standard deviation was 4263.8±1110.8 N for Group LT, 5070.8±1016.4 for Group HT and 6242.0±1759.5 N for Group ST. The values of Group ST were significantly higher than those of the other groups. CONCLUSION Zirconia crowns veneered with CAD/CAM generated glass ceramics by the sintering technique are superior to those veneered with feldspathic porcelain by the layering technique or veneered with glass ceramics by the heat-pressing technique in terms of fracture strength. PMID:22977725

  16. Tensile bond strength of indirect composites luted with three new self-adhesive resin cements to dentin

    PubMed Central

    TÜRKMEN, Cafer; DURKAN, Meral; CİMİLLİ, Hale; ÖKSÜZ, Mustafa

    2011-01-01

    Objective The aims of this study were to evaluate the tensile bond strengths between indirect composites and dentin of 3 recently developed self-adhesive resin cements and to determine mode of failure by SEM. Material and Methods Exposed dentin surfaces of 70 mandibular third molars were used. Teeth were randomly divided into 7 groups: Group 1 (control group): direct composite resin restoration (Alert) with etch-and-rinse adhesive system (Bond 1 primer/adhesive), Group 2: indirect composite restoration (Estenia) luted with a resin cement (Cement-It) combined with the same etch-and-rinse adhesive, Group 3: direct composite resin restoration with self-etch adhesive system (Nano-Bond), Group 4: indirect composite restoration luted with the resin cement combined with the same self-etch adhesive, Groups 5-7: indirect composite restoration luted with self-adhesive resin cements (RelyX Unicem, Maxcem, and Embrace WetBond, respectively) onto the non-pretreated dentin surfaces. Tensile bond strengths of groups were tested with a universal testing machine at a constant speed of 1 mm/min using a 50 kgf load cell. Results were statistically analyzed by the Student's t-test. The failure modes of all groups were also evaluated. Results The indirect composite restorations luted with the self-adhesive resin cements (groups 5-7) showed better results compared to the other groups (p<0.05). Group 4 showed the weakest bond strength (p>0.05). The surfaces of all debonded specimens showed evidence of both adhesive and cohesive failure. Conclusion The new universal self-adhesive resins may be considered an alternative for luting indirect composite restorations onto non-pretreated dentin surfaces. PMID:21710095

  17. Evaluation of the mechanical properties of dental adhesives and glass-ionomer cements.

    PubMed

    Magni, Elisa; Ferrari, Marco; Hickel, Reinhard; Ilie, Nicoleta

    2010-02-01

    Adhesives and lining/base materials should relieve the stresses concentrated at the tooth/restoration interface. The study aimed at comparing the mechanical properties of eight adhesives and six glass-ionomer cements (GICs). The adhesives were applied on dentin disks, whereas 2 mm x 3 mm x 2 mm GICs specimens were prepared in a teflon mold. Vicker's hardness (VH), elastic modulus (E), creep (Cr) and elastic work (We/Wtot) were measured with a micro hardness indenter. One-way ANOVA and Tukey's test were used to compare the mechanical properties within each materials' type and among the materials' classes. Enamel and dentin were used as references. Significant differences were detected within each materials' type and among the materials' classes and enamel and dentin. GICs were superior to adhesives in VH and E and showed a VH similar to dentin. GICs presented mechanical properties more similar to enamel and dentin than adhesives. PMID:19241096

  18. The effect of placement of glass fibers and aramid fibers on the fracture resistance of provisional restorative materials.

    PubMed

    Saygili, Gülbin; Sahmali, Sevil M; Demirel, Figen

    2003-01-01

    The fracture resistance of provisional restorations is an important concern for the restorative dentist. The fracture resistance of a material is directly related to its transverse strength. Six specimens of similar dimensions were prepared from three resins (PMMA, PEMA and BIS acryl-composite). The resins were reinforced with glass and aramid fibers. The samples were tested immediately after the material set, following seven days of wet storage using three-point compression loading. The results were analyzed with an analysis of variance (ANOVA). Fracture resistance of the specimens was statistically different (p < 0.001) among the materials. Specimens reinforced with glass fibers showed higher transverse strength (149.82 MPa). The fiber reinforcement of resin materials increased the strength values (20-50%). Within the limitations of this study, the transverse strengths of PMMA, PEMA and BIS acryl-resin composites were improved after reinforcement with glass and aramid fibers. PMID:12540123

  19. The weight change of various light-cured restorative materials stored in water.

    PubMed

    Keyf, Filiz; Yalçin, Filiz

    2005-05-15

    This study investigated weight changes of seven different light-cured composite restorative materials, one polyacid glass ionomer compomer, and one light-cured glass-ionomer cement following short-term and long-term storage in water. Two packable composites, three universal (hybrid) composites, one microglass composite, one polyacid glass ionomer resin composite (compomer), one microhybrid low-viscosity (flowable) composite, and one light cured glass ionomer composite cement were evaluated in this study. The weight changes of these specimens were measured daily (short-term storage), and they were measured after six weeks (long-term storage) using an electronic analytical balance. A significant difference was found in Ionoliner, Dyract AP, Opticor flow, Charisma, and Solitare 2, but no significant difference was found in the others (Filtek Z 250, Filtek P60, TPH Spectrum, and Valux Plus). Weight change showed a tendency to increase with the time of water storage. The greatest weight change occurred in light-cured glass ionomer composite cement (Ionoliner), which is followed in order by the weight changes in Dyract AP, Opticor Flow, Charisma, Solitare 2, Filtek Z250, Filtek P60, TPH Spectrum; Valux Plus had the least amount of change. PMID:15915206

  20. Effect of Industry Sponsorship on Dental Restorative Trials.

    PubMed

    Schwendicke, F; Tu, Y-K; Blunck, U; Paris, S; Göstemeyer, G

    2016-01-01

    Industry sponsorship was found to potentially introduce bias into clinical trials. We assessed the effects of industry sponsorship on the design, comparator choice, and findings of randomized controlled trials on dental restorative materials. A systematic review was performed via MEDLINE, CENTRAL, and EMBASE. Randomized trials on dental restorative and adhesive materials published 2005 to 2015 were included. The design of sponsored and nonsponsored trials was compared statistically (risk of bias, treatment indication, setting, transferability, sample size). Comparator choice and network geometry of sponsored and nonsponsored trials were assessed via network analysis. Material performance rankings in different trial types were estimated via Bayesian network meta-analysis. Overall, 114 studies were included (15,321 restorations in 5,232 patients). We found 21 and 41 (18% and 36%) trials being clearly or possibly industry sponsored, respectively. Trial design of sponsored and nonsponsored trials did not significantly differ for most assessed items. Sponsored trials evaluated restorations of load-bearing cavities significantly more often than nonsponsored trials, had longer follow-up periods, and showed significantly increased risk of detection bias. Regardless of sponsorship status, comparisons were mainly performed within material classes. The proportion of trials comparing against gold standard restorative or adhesive materials did not differ between trial types. If ranked for performance according to the need to re-treat (best: least re-treatments), most material combinations were ranked similarly in sponsored and nonsponsored trials. The effect of industry sponsorship on dental restorative trials seems limited. PMID:26442947

  1. Effect of Staining Solutions on Color Stability of Silorane & Methacrylate Restorative Material

    PubMed Central

    S. Madhyastha, Prashanthi; G. Naik, Dilip; Kotian, Ravindra; Srikant, N.; M. R. Bhat, Kumar

    2015-01-01

    Color stability throughout the functional lifetime of restorations is important for the durability of treatment and of cosmetic importance. The purpose of this study was to evaluate the discoloration properties of a silorane-based (Filtek P90) and methacrylate-based (Z100) composites upon exposure to different staining solutions that are used on day to day basis (turmeric, tea, coffee, cocoa, lime, yoghurt and distilled water) for different immersion periods (1, 7, 14 and 28 days). The colors of all specimens before and after storage in the solutions were measured by a reflectance spectrophotometer based on CIE Lab system and the color differences were calculated. Data were statistically analyzed by repeated measures of ANOVA and sidak post hoc test (for immersion period);‘t’ test (for each material) and one way ANOVA (for staining agents). All the staining agents showed significant difference in staining over time in both the materials. However, Z100 showed higher quantum of discoloration at all time periods at each staining agents (p<0.005). In conclusion, the silorane-based resin (Filtek P90) composites exhibited better color stability (less change in ΔE) after exposure to the staining solutions. Among the staining agents cocoa was found to be least staining followed by lime, yoghurt, coffee, tea whereas turmeric discolored the composites to the maximum. Highest discoloration was seen at day 28 in all staining agents. Cocoa and lime discolored to maximum at early stages but remained stable thereafter whereas tea, coffee and turmeric progressively discolored the composite over time.

  2. Staphylococcus aureus adhesion to standard micro-rough and electropolished implant materials.

    PubMed

    Harris, Llinos G; Meredith, D Osian; Eschbach, Lukas; Richards, R Geoff

    2007-06-01

    Implant-associated infections can cause serious complications including osteomyelitis and soft tissue damage, and are a great problem due to the emergence of antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). In some cases, antibiotic-loaded beads which release the antibiotic locally have been used, however such systems may lead to the development of antibiotic-resistant bacteria, as seen with gentamicin-loaded beads. Hence modifying the actual metal implant surface to inhibit or reduce initial bacterial adhesion may be an alternative option. This study describes the visualisation and quantification of S. aureus adhering to standard micro-rough 'commercially pure' titanium (TS) and Ti-6Al-7Nb (NS) surfaces, electropolished titanium (TE) and Ti-6Al-7Nb (NE) surfaces, and standard electropolished stainless steel (SS). Qualitative and quantitative results of S. aureus on the different surfaces correlated with each other, and showed significantly more live bacteria on NS than on the other surfaces, whilst there was no significant difference between the amount of bacteria on TS, TE, NE and SS surfaces. The results showed a significant decrease in the amount of bacteria adhering to the NE compared to standard NS surfaces. Such an observation suggests that the NS surface encouraged S. aureus adhesion, and could lead to higher infection rates in vivo. Hence electropolishing Ti-6Al-7Nb surfaces could be advantageous in osteosynthesis areas in minimising bacterial adhesion and lowering the rate of infection. PMID:17268867

  3. Reliability of materials in MEMS : residual stress and adhesion in a micro power generation system.

    SciTech Connect

    Moody, Neville Reid; Kennedy, Marian S.; Bahr, David F.

    2007-09-01

    The reliability of thin film systems is important to the continued development of microelectronic and micro-electro-mechanical systems (MEMS). The reliability of these systems is often tied to the ability of the films to remain adhered to its substrate. By measuring the amount of energy to separate the film from the substrate, researchers can predicts film lifetimes. Recent work has resulted in several different testing techniques to measure this energy including spontaneous buckling, indentation induced delamination and four point bending. This report focuses on developing quantifiable adhesion measurements for multiple thin film systems used in MEMS and other thin film systems of interest to Sandia programs. First, methods of accurately assessing interfacial toughness using stressed overlayer methods are demonstrated using both the W/Si and Au/Si systems. For systems where fracture only occurs along the interface, such as Au/Si, the calculated fracture energies between different tests are identical if the energy put into the system is kept near the needed strain energy to cause delamination. When the energy in the system is greater than needed to cause delamination, calculated adhesion energies can increase by a factor of three due to plastic deformation. Dependence of calculated adhesion energies on applied energy in the system was also shown when comparisons of four point bending and stressed overlayer test methods were completed on Pt/Si systems. The fracture energies of Pt/Ti/SiO{sub 2} were studied using four-point bending and compressive overlayers. Varying the thickness of the Ti film from 2 to 17 nm in a Pt/Ti/SiO{sub 2} system, both test methods showed an increase of adhesion energy until the nominal Ti thickness was 12nm. Then the adhesion energy began to decrease. While the trends in toughness are similar, the magnitude of the toughness values measured between the test methods is not the same, demonstrating the difficulty in extracting mode I toughness

  4. Infection of orthopedic implants with emphasis on bacterial adhesion process and techniques used in studying bacterial-material interactions

    PubMed Central

    Ribeiro, Marta; Monteiro, Fernando J.; Ferraz, Maria P.

    2012-01-01

    Staphylococcus comprises up to two-thirds of all pathogens in orthopedic implant infections and they are the principal causative agents of two major types of infection affecting bone: septic arthritis and osteomyelitis, which involve the inflammatory destruction of joint and bone. Bacterial adhesion is the first and most important step in implant infection. It is a complex process influenced by environmental factors, bacterial properties, material surface properties and by the presence of serum or tissue proteins. Properties of the substrate, such as chemical composition of the material, surface charge, hydrophobicity, surface roughness and the presence of specific proteins at the surface, are all thought to be important in the initial cell attachment process. The biofilm mode of growth of infecting bacteria on an implant surface protects the organisms from the host immune system and antibiotic therapy. The research for novel therapeutic strategies is incited by the emergence of antibiotic-resistant bacteria. This work will provide an overview of the mechanisms and factors involved in bacterial adhesion, the techniques that are currently being used studying bacterial-material interactions as well as provide insight into future directions in the field. PMID:23507884

  5. Design and characterization of materials with microphase-separated surface patterns for screening osteoblast response to adhesion

    NASA Astrophysics Data System (ADS)

    Wingkono, Gracy A.

    Combinatorial techniques have changed the paradigm of materials research by allowing efficient screening of complex materials problems with large, multidimensional parameter spaces. The focus of this thesis is to demonstrate combinatorial methods (CM) and high-throughput methods (HTM) applied to biomaterials design, characterization, and screening. In particular, this work focuses on screening the effects of biomaterial surface features on adherent bone cell cultures. Polymeric biomaterials were prepared on two-dimensional combinatorial libraries that systematically varied the size and shape of chemically-distinct microstructural patterns. These libraries were generated from blends of biodegradable polyurethanes and polyesters prepared with thickness, composition and temperature gradient techniques. Characterization and screening were performed with high-throughput optical and fluorescence microscopy. A unique advance of this work is the application of data mining techniques to identify the controlling structural features that affect cell behavior from among the myriad variety of metrics from the microscope images. Libraries were designed to exhibit chemically-distinct cell-adhesive versus non-adhesive microstructural domains that improve library performance compared to previous implementations that had employed only modest chemical differences. Improving adhesive contrast should minimize combination of effects of chemistry and physical structure, making data interpretation simpler. To accomplish this, a method of blending and crosslinking cell-non-adhesive poly(ethylene glycol) (PEG) with cell-adhesive poly(·-caprolactone) (PCL) was developed. The behavior of MC3T3-E1 osteoblast cells cultured on the PCL-PEG libraries were observed, equivalent to thousands of distinct chemistries and microstructures. Cell spreading area, shape, and density upon adhesion on surface patterns are observed in this study. Characterization of the surface library and screening of

  6. Damage analysis in composite materials and design of adhesive joints for composite structures

    NASA Astrophysics Data System (ADS)

    Zhang, Jian

    design of adhesive joints for composite structures . A new approach was explored for joining of thick, woven E-glass/vinyl ester composite laminated plates to steel or composite plates, with applications in naval ship structures. Adhesive was applied along through-the-thickness contoured interfaces, employing tongue-and-groove geometry. Both experimental and finite element modeling results were presented. They showed that adhesively bonded tongue-and-groove joints between steel and composite plates loaded in monotonically increasing longitudinal tension are stronger than conventional strap joints even in relatively thin plates. In particular, a single 0.25 in. wide and 8 or 12 in. long steel tongue, bonded by the Dexter-Hysol 9339 adhesive to a groove in a 0.5 in. thick laminated plate, can support a 20,000 lbs tension force. This force was expected to increase in proportion to plate thickness. Simple design rules indicate that the adhesive bond can be made stronger than that of the tongues, so that failure was transferred from the adhesive to the adherends. High joint efficiency can be achieved for any thickness of the joined plates.

  7. A Comparison of 2-Octyl Cyanoacrylate Adhesives versus Conventional Suture Materials for Eyelid Wound Closure in Rabbits

    PubMed Central

    Shin, Dong-Min; Roh, Mee-Sook; Jeung, Woo-Jin; Park, Woo-Chan; Rho, Sae-Heun

    2011-01-01

    Purpose To evaluate the clinical efficacy and histopathological tolerance of 2-octyl cyanoacrylate versus conventional suture materials for eyelid wound closure in rabbits. Methods We performed an experimental study on 16 eyes of eight New Zealand albino rabbits. Eyelid incisions of 15 mm were done 4mm from the upper eyelid margin in both eyes. The eyes of the rabbits were divided into two groups: eyelid incisions of the right eye were closed by a 2-octyl cyanoacrylate adhesive (group A) and eyelid incisions of the left eye were closed by 7-0 nylon sutures (group B). At 1, 2, 4, and 8 weeks after surgery, the rabbits were macroscopically examined and then sacrificed. The specimens of their eyelid tissues were stained by a hematoxylin and eosin stain and Masson-trichrome stain, and were observed under microscope. Results Both eyelid surgical closure methods were found to be equally efficacious in fixing the eyelids of groups A and B, and their clinical efficacy was similar. Histopathological findings of the hematoxylin and eosin stain of group A showed less inflammatory infiltration than group B at 2 weeks. There were no significant histopathological differences between the two groups at 1, 4, and 8 weeks. The degree of fibrosis of the Masson-trichrome stain was similar between the two groups at 8 weeks. Conclusions The 2-octyl cyanoacrylate adhesive proved to be an effective eyelid closure method and was very well tolerated by the skin surface. 2-Octyl cyanoacrylate could be used as an alternative tissue adhesive for eyelid wound closure along with conventional suture materials. PMID:21461225

  8. Current opinions concerning the restoration of endodontically treated teeth: basic principles

    PubMed Central

    VȦrlan, C; VȦrlan, V; Bodnar, D; Suciu, I

    2009-01-01

    The goal of this general article is to present a survey of the current knowledge about the clinical approach of restoring endodontically treated teeth. The best way to restore teeth after root canal treatment has long been and still is a controversial subject of debate to this day. The clinical approach of restoring endodontically treated teeth needs taking into consideration several issues: aims of coronal restoration, criteria for establishing the various modalities of coronal restoration, clinical solutions of restoring teeth after endodontic treatment, guidelines regarding restorative materials and techniques, possibilities and limits of restoration using direct adhesive materials and techniques. The aims of coronal restoration of endodontically treated teeth are generally considered to be the following ones: to prevent recontamination of the root canal system and / or periapical space, to replace missing hard dental tissues and to restore coronal morphology and functions, to provide the necessary strength for the restoration/tooth complex in order to withstand functional stress and prevent crown and/or root fracture. The criteria for establishing the modalities of coronal restoration for endodontically treated teeth are: amount and quality of remaining hard dental tissues, topography and coronal morphology of the tooth, functional occlusal forces that the restoration/tooth complex has to withstand, restoring requirements in order to include the treated tooth in a comprehensive oral rehabilitation treatment plan, esthetic requirements. PMID:20108535

  9. Multiwalled Carbon Nanotube/nanofiber Arrays as Conductive and Dry Adhesive Interface Materials

    NASA Technical Reports Server (NTRS)

    Tong, Tao; Zhao, Yang; Delzeit, Lance; Majumdar, Arun; Kashani, Ali

    2004-01-01

    We demonstrate the possibility of making conductive and dry adhesive interfaces between multiwalled carbon nanotube (MWNT) and nanofiber (MWNF) arrays grown by chemical vapor deposition with transition-metal as catalyst on highly Boron doped silicon substrates. The maximum observed adhesion force between MWNT and MWNF surfaces is 3.5 mN for an apparent contact area of 2 mm by 4 mm. The minimum contact resistance measured at the same time is approx.20 Omega. Contact resistances of MWNT-MWNT and MWNT-gold interfaces were also measured as pressure forces around several mN were applied at the interface. The resulting minimum contact resistances are on the same order but with considerable variation from sample to sample. For MWNT-MWNT contacts, a minimum contact resistance of approx.1 Omega is observed for a contact area of 2 mm by 1 mm. The relatively high contact resistances, considering the area density of the nanotubes, might be explained by the high cross-tube resistances at the contact interfaces.

  10. Optical properties of dental restorative materials in the wavelength range 400 to 700 nm for the simulation of color perception

    NASA Astrophysics Data System (ADS)

    Friebel, Moritz; Povel, Kirsten; Cappius, Hans-Joachim; Helfmann, Jürgen; Meinke, Martina

    2009-09-01

    Aesthetic restorations require dental restorative materials to have optical properties very similar to those of the teeth. A method is developed to this end to determine the optical parameters absorption coefficient μa, scattering coefficient μs, anisotropy factor g, and effective scattering coefficient μs' of dental restorative materials. The method includes sample preparation and measurements of transmittance and reflectance in an integrating sphere spectrometer followed by inverse Monte Carlo simulations. Using this method the intrinsic optical parameters are determined for shade B2 of the light-activated composites TPH® Spectrum®, Esthet-X®, and the Ormocer® Definite® in the wavelength range 400 to 700 nm. By using the determined parameters μa, μs, and g together with an appropriate phase function, the reflectance of samples with 1-mm layer thickness and shade B2 could be predicted with a very high degree of accuracy using a forward Monte Carlo simulation. The color perception was calculated from the simulated reflectance according to the CIELAB system. We initiate the compilation of a data pool of optical parameters that in the future will enable calculation models to be used as a basis for optimization of the optical approximation of the natural tooth, and the composition of new materials and their production process.

  11. Three-dimensional finite element analysis of stress distribution in inlay-restored mandibular first molar under simultaneous thermomechanical loads.

    PubMed

    Çelik Köycü, Berrak; Imirzalioğlu, Pervin; Özden, Utku Ahmet

    2016-01-01

    Functional occlusal loads and intraoral temperature changes create stress in teeth. The purpose of this study was to evaluate the impact of simultaneous thermomechanical loads on stress distribution related to inlay restored teeth by three-dimensional finite element analysis. A mandibular first molar was constructed with tooth structures, surrounding bone and inlays of Type II gold alloy, ceramic, and composite resin. Stress patterns on the restorative materials, adhesive resin, enamel and dentin were analyzed after simulated temperature changes from 36°C to 4 or 60°C for 2 s with 200-N oblique loading. The results showed that the three types of inlays had similar stress distribution in the tooth structures and restorative materials. Concerning the adhesive resin, the composite resin inlay model exhibited lower stresses than ceramic and gold alloy inlays. Simultaneous thermomechanical loads caused high stress patterns in inlay-restored teeth. Composite resin inlays may be the better choice to avoid adhesive failure. PMID:27041006

  12. Adhesives in Building--Lamination of Structural Timber Beams, Bonding of Cementitious Materials, Bonding of Gypsum Drywall Construction. Proceedings of a Conference of the Building Research Institute, Division of Engineering and Industrial Research (Spring 1960).

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    The role of adhesives in building design is discussed. Three major areas are as follows--(1) lamination of structural timber beams, (2) bonding of cementitious materials, and (3) bonding of gypsum drywall construction. Topical coverage includes--(1) structural lamination today, (2) adhesives in use today, (3) new adhesives needed, (4) production…

  13. Finite element modeling of dental restoration through multi-material laser densification

    NASA Astrophysics Data System (ADS)

    Dai, Kun

    To provide guidance for intelligent selection of various parameters in the Multi-Material Laser Densification (MMLD) process for dental restorations, finite element modeling (FEM) has been carried out to investigate the MMLD process. These modeling investigations include the thermal analysis of the nominal surface temperature that should be adopted during experiments in order to achieve the desired microstructure; the effects of the volume shrinkage due to transformation from a powder compact to dense liquid on the temperature distribution and the size of the transformation zone; the evolution of transient temperature, transient stresses, residual stresses and distortions; and the effects of laser processing conditions, such as fabrication sequences, laser scanning patterns, component sizes, preheating temperatures, laser scanning rates, initial porosities, and thicknesses of each powder layer, on the final quality of the component fabricated via the MMLD process. The simulation results are compared with the experiments. It is found that the predicted temperature distribution matches the experiments very well. The nominal surface temperature applied on the dental porcelain body should be below 1273 K to prevent the forming of the un-desired microstructure (i.e., a leucite-free glassy phase). The simplified models that do not include the volume shrinkage effect provide good estimations of the temperature field and the size of the laser-densified body, although the shape of the laser-densified body predicted is different from that obtained in the experiment. It is also fount that warping and residual thermal stresses of the laser-densified component are more sensitive to the chamber preheating temperature and the thickness of each powder layer than to the laser scanning rate and the initial porosity of the powder layer. The major mechanism responsible for these phenomena is identified to be related to the change of the temperature gradient induced by these laser

  14. Bacteriology of deep carious lesions underneath amalgam restorations with different pulp-capping materials - an in vivo analysis

    PubMed Central

    NEELAKANTAN, Prasanna; RAO, Chandragiri Venkata Subba; INDRAMOHAN, Jamuna

    2012-01-01

    Microorganisms remaining in dentin following cavity preparation may induce pulp damage, requiring the use of pulp-capping agents with antimicrobial activity underneath permanent restorations. Objective The aims of this study were to analyze the bacteriological status of carious dentin and to assess the efficacy of different base underneath silver amalgam restorations. Material and Methods This study was conducted on 50 patients aged 13 to 30 years. Sterile swabs were used to take samples after cavity preparation, which was assessed by microbiological culture to identify the microorganisms present. Following this, cavities were restored with silver amalgam, using one of the materials being investigated, as the base: calcium hydroxide (Group II), polyantibiotic paste (Group III), a novel light-cured fluoride-releasing hydroxyapatite-based liner (Group IV) and mineral trioxide aggregate - MTA (Group V). In Group I, the cavities were restored with silver amalgam, without any base. After 3 months, the amalgam was removed and samples taken again and analyzed for the microbial flora. Results Lactobacilli were the most commonly isolated microorganisms in the samples of carious dentin. Groups IV and V showed negative culture in the 3-month samples. There was no statistically significant difference between Groups I, II and III. There was no significant difference between Groups IV and V (p>0.05). Both Groups IV and V showed significantly better results when compared to Groups I, II and III (p<0.05). Conclusions The hydroxyapatite-based liner and MTA performed significantly better in terms of antibacterial activity than the other materials. PMID:22666827

  15. Adhesion and friction of transition metals in contact with nonmetallic hard materials

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1981-01-01

    Sliding friction experiments were conducted with the metals yttrium, titanium, tantalum, zirconium, vanadium, neodymium, iron, cobalt, nickel, tungsten, platinum, rhenium, ruthenium, and rhodium in sliding contact with single crystal diamond, silicon carbide, pyrolytic boron nitride, and ferrite. Auger electron spectroscopy analysis was conducted with the metals and nonmetals to determine the surface chemistry and the degree of surface cleanliness. The results of the investigation indicate the adhesion and friction of the transition metals in contact with diamond, silicon carbide, boron nitride, and ferrite are related to the relative chemical activity of the metals. The more chemically active the metal, the higher the coefficient of friction and the greater amount of transfer to the nonmetals.

  16. The effects of ambient temperature and mixing time of glass ionomer cement material on the survival rate of proximal ART restorations in primary molars

    PubMed Central

    Kemoli, Arthur M

    2014-01-01

    Objective: Temperature fluctuations and material mixing times are likely to affect the consistency and integrity of the material mixture, and hence the restoration made out of it. The purpose of the present study was to determine the influence of the ambient temperature and the mixing time of glass ionomer cement (GIC) restorative material on the survival rate of proximal atraumatic restorative treatment (ART) restorations placed in primary molars. Materials and Methods: A total of 804 restorations were placed in the primary molars of 6-8-year-olds using the ART approach. The restorations were then followed for a period of 2 years and evaluated at given intervals. The data collected were analyzed using SPSS computer statistical program, and the results tested and compared using the Chi-square, Kaplan Meier survival analysis and Cox Proportional hazard statistical tests. Results: The cumulative survival rate of the restorations dropped from the initial 94.4% to 30.8% at the end of 2 years. The higher survival rate of the restorations was associated with the experienced operators and assistants when using the rubber dam isolation method. However, there was no statistically significant difference in the survival rate of the restorations when related to the room temperature and the mixing time of the GIC materials used in spite of the variations in the temperature recoded and the methods used in mixing the materials. Conclusion: The ambient temperature and mixing time of GIC did not have a significant effect on the survival of the proximal ART restorations. PMID:24808692

  17. Effect of Production Conditions of Wood Powder on Bending Properties of Wood Powder Molding Material without Adhesive

    NASA Astrophysics Data System (ADS)

    Imanishi, Hiroshi; Soma, Naho; Yamashita, Osamu; Miki, Tsunehisa; Kanayama, Kozo

    The effect of production conditions of wood powder on the bending properties of wood powder molding material was investigated. Wood powder was produced by milling wood into powder under conditions of different temperatures (25°C, 100°C) and moisture contents (0%MC, about 30%MC). Molding materials were produced from wood powder in stream atmosphere of high temperature and high pressure (175°C, 900kPa) using self-bonding ability of the wood powder. Adhesives, such as a synthetic resin, were not used. To evaluate the bending properties of the molding materials, the modulus of elasticity and the bending strength were examined by static three-point bending test. As for the characteristic of wood particle, in case of wood particle produced by milling wood under a condition of high temperature and high moisture content (100°C and about 30%MC), tendencies for intercellular layer to be exposed on surface of a particle and for the aspect ratio of particles to be large were confirmed. And in that case, the molding material showed the highest value in modulus of elasticity and bending strength. It is highly probable that the inprovement of the self-bonding ability of wood powder and the increase of the aspect ratio of wood particle take part in the improvement of strength properties of molding material.

  18. Spectroscopic and morphologic characterization of the dentin/adhesive interface

    NASA Astrophysics Data System (ADS)

    Lemor, R. M.; Kruger, Michael B.; Wieliczka, David M.; Swafford, Jim R.; Spencer, Paulette

    1999-01-01

    The potential environmental risks associated with mercury release have forced many European countries to ban the use of dental amalgam. Alternative materials such as composite resins do not provide the clinical function for the length of time characteristically associated with dental amalgam. The weak link in the composite restoration is the dentin/adhesive bond. The purpose of this study was to correlate morphologic characterization of the dentin/adhesive bond with chemical analyses using micro- Fourier transform infrared and micro-Raman spectroscopy. A commercial dental adhesive was placed on dentin substrates cut from extracted, unerupted human third molars. Sections of the dentin/adhesive interface were investigated using infrared radiation produced at the Aladdin synchrotron source; visible radiation from a Kr+ laser was used for the micro-Raman spectroscopy. Sections of the dentin/adhesive interface, differentially stained to identify protein, mineral, and adhesive, were examined using light microscopy. Due to its limited spatial resolution and the unknown sample thickness the infrared results cannot be used quantitatively in determining the extent of diffusion. The results from the micro-Raman spectroscopy and light microscopy indicate exposed protein at the dentin/adhesive interface. Using a laser that reduces background fluorescence, the micro-Raman spectroscopy provides quantitative chemical and morphologic information on the dentin/adhesive interface. The staining procedure is sensitive to sites of pure protein and thus, complements the Raman results.

  19. Use of two surface analyzers to evaluate the surface roughness of four esthetic restorative materials after polishing.

    PubMed

    Joniot, Sabine; Salomon, Jean Pierre; Dejou, Jacques; Grégoire, Geneviève

    2006-01-01

    This study had two aims: determine how well four esthetic restorative materials lent themselves to polishing and compare the results obtained using two different techniques for evaluating surface roughness. The four materials used were two composites modified by the addition of resin, Dyract AP (Dentsply) and Dyract Flow (Dentsply); one composite designed for posterior restorations, SureFil (Dentsply) and one universal micromatrix composite, Esthet-X (Dentsply). Five test pieces were made with each product by inserting the material into cylindrical molds and polymerizing it layer by layer. A single operator polished the specimens on the same day using the Enhance system (Dentsply) and two aluminum oxide pastes. The surfaces were studied successively by means of two surface analyzers: a high-resolution optical profilometer (Nanosurf 488, SAS Technology) and a mechanical profilometer (Mitutoyo Surftest-SV 402). These measurements gave the mean roughness of the surface (Ra). Ten zones were examined for each specimen, and the specimens were observed under an optical microscope (PMG3 inverted metallographic microscope) at 50x magnification. The qualitative and quantitative analyses of the results showed good surface states for all materials. However, the composites based on nano- and micro-filler technology gave the smoothest surfaces after polishing. A comparison of the values obtained with each method of observation showed that mechanical profilometry tended to show roughness caused by polishing, while optical profilometry brought out roughness due to the structure of the material itself. PMID:16536192

  20. The Market Gate of Miletus: damages, material characteristics and the development of a compatible mortar for restoration

    NASA Astrophysics Data System (ADS)

    Siegesmund, Siegfried; Middendorf, Bernhard

    2008-12-01

    The indoor exhibit of the Market Gate of Miletus is unique for an archaeological monument. The reconstruction of the gate was done in such a way that most marble fragments were removed leaving cored marble columns 3-4 cm in thickness. These cored columns were mounted on a steel construction and filled with different mortars or filled with specially shaped blocks of brick combined with mortar. All the missing marble elements were replaced by copies made of a Portland cement based concrete, which is compositionally similar to the original building materials. During the Second World War the monument was heavily damaged by aerial bombardment. For 2 years the Market Gate of Miletus was exposed to weathering, because a brick wall protecting the gate was also destroyed. The deterioration phenomena observed are microcracks, macroscopic fractures, flaking, sugaring, greying, salt efflorescence, calcitic-sinter layers and iron oxide formation etc. The rapid deterioration seems to be due to indoor atmospheric effects, and also by a combination of incompatible materials (e.g. marble, steel, mortar, concrete, bricks etc.). Compatible building materials like mortars or stone replacing materials have to be developed for the planned restoration. The requirements for restoration mortars are chemical-mineralogical and physical-mechanical compatibilities with the existing building materials. In detail this means that the mortar should ensure good bonding properties, adapted strength development and not stain the marble when in direct contact. The favoured mortar was developed with a hydraulic binder based on iron-free white cement and pozzolana based on activated clay. A special limestone and quartz sand mixture was used as an aggregate. The cement was adjusted using chemical additives. Specially designed tests were applied extensively to prove whether the developed mortar is suitable for the restoration of this precious monument.

  1. Principles of restorative dentistry.

    PubMed

    Banker, T

    1993-08-01

    A great deal of information regarding materials, instrumentation, and techniques used for restorative dentistry can be borrowed from the human dental field. Veterinary restorative dentistry is in its infancy. A thorough knowledge of the commonly used materials and how they can be effectively applied is important. Treatment planning is probably one of the most critical phases of restorative dentistry as is painstaking attention to detail. If the guidelines for restorative dental techniques are followed, failures will be minimal. However, one of the most important points to remember is that the success of a restoration is not determined at the completion of the procedure. A restoration, if properly planned and performed, should last the lifetime of the animal patient. It is very important that veterinary dentists continue to evaluate and assess their restorative work at regular intervals so that restorative failures can be detected early, and so that restorative techniques and materials can be critically evaluated in veterinary patients. PMID:8210800

  2. Effect of surface treatment and liner material on the adhesion between veneering ceramic and zirconia.

    PubMed

    Yoon, Hyung-in; Yeo, In-sung; Yi, Yang-jin; Kim, Sung-hun; Lee, Jai-bong; Han, Jung-suk

    2014-12-01

    Fully sintered zirconia blocks, each with one polished surface, were treated with one of the followings: 1) no treatment, 2) airborne-particle abrasion with 50μm alumina, and 3) airborne-particle abrasion with 125μm alumina. Before veneering with glass ceramic, either liner Α or liner B were applied on the treated surfaces. All veneered blocks were subjected to shear force in a universal testing machine. For the groups with liner A, irrespective of the particle size, air abrasion on Y-TZP surfaces provided greater bond strength than polishing. Application of liner B on an abraded zirconia surface yielded no significant influence on the adhesion. In addition, specimens with liner A showed higher bond strength than those with liner B, if applied on roughened surfaces. Fractured surfaces were observed as mixed patterns in all groups. For the liner A, surface treatment was helpful in bonding with veneering ceramic, while it was ineffective for the liner B. PMID:25282467

  3. Effect of a glaze/composite sealant on the 3-D surface roughness of esthetic restorative materials.

    PubMed

    Perez, Cesar dos Reis; Hirata, Raphael Júnior; da Silva, Antonio Henrique Monteiro da Fonseca Thomé; Sampaio, Eduardo Martins; de Miranda, Mauro Sayão

    2009-01-01

    The main goal of the current study was to evaluate the surface roughness of tooth-colored restorative materials after different finishing/polishing protocols, including a liquid polisher (BisCover, BISCO, Schaumburg, IL, USA). The restorative materials tested included two nanofilled resin composites (Filtek Supreme, 3M Dental Products, St Paul, MN, USA and Grandio, Voco, Cuxhaven, Germany), one resin-modified glass ionomer cement (Vitremer, 3M Dental Products) and one conventional glass ionomer cement (Meron Molar ART, Voco). The finishing/polishing methods were divided into five groups: G1 (compression with Mylar matrix), G2 (finishing with diamond burs), G3 (Sof-Lex, 3M Dental Products), G4 (BisCover, BISCO, after diamond burs) and G5 (BisCover after Sof-Lex). Five cylindrical specimens of each material were prepared for each group according to the manufacturer's instructions. The finishing/polishing methods were performed by a single operator in one direction to avoid variations at low speed (15,000 RPM). The surface roughness was evaluated using a 3-D scanning instrument with two parameters considered (Ra and Rz). The data was analyzed using one-way ANOVA followed by a multiple comparison Tukey's test. The results showed that BisCover (BISCO) was capable of reducing surface roughness and provided polished surfaces for all materials, enhancing smoothness over already polished surfaces (Sof-Lex, 3M Dental Products) and achieving polishing after finishing with diamond burs. PMID:19953776

  4. Bond strength of self-adhesive resin cements to composite submitted to different surface pretreatments

    PubMed Central

    dos Santos, Victor Hugo; Griza, Sandro; de Moraes, Rafael Ratto

    2014-01-01

    Objectives Extensively destroyed teeth are commonly restored with composite resin before cavity preparation for indirect restorations. The longevity of the restoration can be related to the proper bonding of the resin cement to the composite. This study aimed to evaluate the microshear bond strength of two self-adhesive resin cements to composite resin. Materials and Methods Composite discs were subject to one of six different surface pretreatments: none (control), 35% phosphoric acid etching for 30 seconds (PA), application of silane (silane), PA + silane, PA + adhesive, or PA + silane + adhesive (n = 6). A silicone mold containing a cylindrical orifice (1 mm2 diameter) was placed over the composite resin. RelyX Unicem (3M ESPE) or BisCem (Bisco Inc.) self-adhesive resin cement was inserted into the orifices and light-cured. Self-adhesive cement cylinders were submitted to shear loading. Data were analyzed by two-way ANOVA and Tukey's test (p < 0.05). Results Independent of the cement used, the PA + Silane + Adhesive group showed higher microshear bond strength than those of the PA and PA + Silane groups. There was no difference among the other treatments. Unicem presented higher bond strength than BisCem for all experimental conditions. Conclusions Pretreatments of the composite resin surface might have an effect on the bond strength of self-adhesive resin cements to this substrate. PMID:24516824

  5. An experimental and numerical study on the effect of some properties of non-metallic materials on the ice adhesion level

    NASA Astrophysics Data System (ADS)

    Piles Moncholi, Eduardo

    The rise of environmentalism in every sector of industry has led aircraft and engine manufacturing companies to develop new generations of more environmentally friendly engines. Companies are in a constant search for new manufacturing and production techniques in order to improve their products, from the environmental point of view, by gaining efficiency in manufacturing techniques and reduce the fuel consumption and emissions in-flight. Having this scenario in mind, the sponsor of this project is interested in understanding how changing the blade materials, currently titanium alloys, for other lighter materials, such as composites, is going to have an effect on overall gas turbine efficiency. In this Project the influence of the stiffness and coating thickness of those non-metallic materials suitable to be employed as coatings on gas turbine fan blades, from the icing point of view, are studied. The methodology is based on a study of linear elastic fracture mechanics of bi-material junctions and will extrapolate the general problem to the ice-coatings case, by obtaining experimental data from tests carried out in an icing tunnel. It was observed that the coating stiffness has an influence on the adhesion level of ice to less stiff materials, if compared with the adhesion level of ice to metals. We also describe how a 0.5 millimetre thin polymeric coating placed over a metallic substrate is enough to reduce the adhesion level of ice, hiding any effect that the underneath materials might have on the adhesion level..

  6. Biodentine versus Mineral Trioxide Aggregate versus Intermediate Restorative Material for Retrograde Root End Filling: An Invitro Study

    PubMed Central

    Soundappan, Saravanapriyan; Sundaramurthy, Jothi Latha; Raghu, Sandhya; Natanasabapathy, Velmurugan

    2014-01-01

    Objective The aim of this study was to evaluate the marginal adaptation of Biodentine in comparison with Mineral Trioxide Aggregate (MTA) and Intermediate Restorative Material (IRM), as a root end filling material, using Scanning Electron Microscopy (SEM). Materials and Methods: Thirty permanent maxillary central incisors were chemo-mechanically prepared and obturated. Three millimetres of the root end were resected and 3mm retro cavity preparation was done using ultrasonic retrotips. The samples were randomly divided into three groups (n=10) and were restored with root end filling materials: Group I – MTA, Group II – Biodentine, Group III – IRM. The root ends were sectioned transversely at 1mm and 2mm levels and evaluated for marginal adaptation using SEM. The gap between dentin and retro filling material was measured at four quadrants. The mean gap at 1mm level and 2mm level from the resected root tip and combined mean were calculated. The data were statistically analyzed, using one-way ANOVA and Tukey’s HSD post hoc test for intergroup analysis and paired t-test for intragroup analysis. Results: The overall results showed no statistically significant difference between MTA and IRM but both were superior when compared to Biodentine. At 1mm level there was no statistically significant difference among any of the tested materials. At 2mm level MTA was superior to both IRM and Biodentine. Conclusion: In overall comparison, MTA and IRM were significantly superior when compared to Biodentine in terms of marginal adaptation, when used as retrograde filling material. PMID:24910689

  7. Evaluation of antibacterial and remineralizing nanocomposite and adhesive in rat tooth cavity model

    PubMed Central

    Li, Fang; Wang, Ping; Weir, Michael D.; Fouad, Ashraf F.; Xu, Hockin H. K.

    2014-01-01

    Antibacterial and remineralizing dental composites and adhesives were recently developed to inhibit biofilm acids and combat secondary caries. It is not clear what effect these materials will have on dental pulps in vivo. The objectives of this study were to investigate the antibacterial and remineralizing restorations in a rat tooth cavity model, and determine pulpal inflammatory response and tertiary dentin formation. Nanoparticles of amorphous calcium phosphate (NACP) and antibacterial dimethylaminododecyl methacrylate (DMADDM) were synthesized and incorporated into a composite and an adhesive. Occlusal cavities were prepared in the first molars of rats and restored with four types of restoration: Control composite and adhesive; control plus DMADDM; control plus NACP; and control plus both DMADDM and NACP. At 8 or 30 days (d), rat molars were harvested for histological analysis. For inflammatory cell response, regardless of time periods, NACP group and DMADDM+NACP group showed lower scores (better biocompatibility) than control group (p = 0.014 for 8 d, p = 0.018 for 30 d). For tissue disorganization, NACP and DMADDM+NACP had better scores than control (p = 0.027) at 30 d. At 8 d, restorations containing NACP had tertiary dentin thickness (TDT) that was 5-6 fold that of control. At 30 d, restorations containing NACP had TDT that was 4-6 fold that of control. In conclusion, novel antibacterial and remineralizing restorations were tested in rat teeth in vivo for the first time. Composite and adhesive containing NACP and DMADDM exhibited milder pulpal inflammation and much greater tertiary dentin formation, than control adhesive and composite. Therefore, the novel composite and adhesive containing NACP and DMADDM are promising as a new therapeutic restorative system to not only combat oral pathogens and biofilm acids as shown previously, but also facilitate the healing of the dentin-pulp complex. PMID:24583320

  8. Evaluation of antibacterial and remineralizing nanocomposite and adhesive in rat tooth cavity model.

    PubMed

    Li, Fang; Wang, Ping; Weir, Michael D; Fouad, Ashraf F; Xu, Hockin H K

    2014-06-01

    Antibacterial and remineralizing dental composites and adhesives were recently developed to inhibit biofilm acids and combat secondary caries. It is not clear what effect these materials will have on dental pulps in vivo. The objectives of this study were to investigate the antibacterial and remineralizing restorations in a rat tooth cavity model, and determine pulpal inflammatory response and tertiary dentin formation. Nanoparticles of amorphous calcium phosphate (NACP) and antibacterial dimethylaminododecyl methacrylate (DMADDM) were synthesized and incorporated into a composite and an adhesive. Occlusal cavities were prepared in the first molars of rats and restored with four types of restoration: control composite and adhesive; control plus DMADDM; control plus NACP; and control plus both DMADDM and NACP. At 8 or 30days, rat molars were harvested for histological analysis. For inflammatory cell response, regardless of time periods, the NACP group and the DMADDM+NACP group showed lower scores (better biocompatibility) than the control group (p=0.014 for 8days, p=0.018 for 30days). For tissue disorganization, NACP and DMADDM+NACP had better scores than the control (p=0.027) at 30days. At 8days, restorations containing NACP had a tertiary dentin thickness (TDT) that was five- to six-fold that of the control. At 30days, restorations containing NACP had a TDT that was four- to six-fold that of the control. In conclusion, novel antibacterial and remineralizing restorations were tested in rat teeth in vivo for the first time. Composite and adhesive containing NACP and DMADDM exhibited milder pulpal inflammation and much greater tertiary dentin formation than the control adhesive and composite. Therefore, the novel composite and adhesive containing NACP and DMADDM are promising as a new therapeutic restorative system to not only combat oral pathogens and biofilm acids as shown previously, but also facilitate the healing of the dentin-pulp complex. PMID:24583320

  9. Effect of Dietary Simulating Solvents on the Mechanical Properties of Provisional Restorative Materials-An In Vitro Study.

    PubMed

    Muley, Bipin Y; Shaikh, Sameera R; Tagore, Mohana M; Khalikar, Arun N

    2014-12-01

    The purpose of this investigation was to evaluate the mechanical properties of provisional restorative materials after storage in dietary simulating solvents. A total of 120 specimens, 40 specimens each of Luxatemp Star, Revotek LC and DPI Self Cure were prepared. The specimens were divided into four groups with 10 specimens each and stored in dietary simulating solvents for 7 days at 37 °C as follows: Group I-Control, Group II-Artificial saliva, Group III-0.02 N Citric acid and Group IV-Heptane. After 7 days, flexural strength was obtained using universal testing machine at a crosshead speed of 5 mm/min and the fractured specimens were immediately subjected to the microhardness test knoop hardness number by using Knoop microhardness tester (10 gm/15 s). The data were analyzed for difference by use of Kruskal-Wallis and Dunn's multiple comparison tests using a significance level of 0.05 to determine the mean differences. Significant effect was observed on the properties of provisional restorative materials after storage in dietary simulating solvents as compared to the control group (p ≤ 0.05). Bis-acryl resin based Luxatemp Star showed significantly superior flexural strength and hardness as compared to the Revotek LC and DPI Self Cure in dietary simulating solvents. Within the limitations of this study, it may be concluded that dietary simulating solvents showed significant influence on the mechanical properties of the provisional restorative materials. PMID:26199498

  10. Dental repair material: a resin-modified glass-ionomer bioactive ionic resin-based composite.

    PubMed

    Croll, Theodore P; Berg, Joel H; Donly, Kevin J

    2015-01-01

    This report documents treatment and repair of three carious teeth that were restored with a new dental repair material that features the characteristics of both resin-modified glass-ionomer restorative cement (RMGI) and resin-based composite (RBC). The restorative products presented are reported by the manufacturer to be the first bioactive dental materials with an ionic resin matrix, a shock-absorbing resin component, and bioactive fillers that mimic the physical and chemical properties of natural teeth. The restorative material and base/liner, which feature three hardening mechanisms, could prove to be a notable advancement in the adhesive dentistry restorative materials continuum. PMID:25822408

  11. Critical factors affecting the 3D microstructural formation in hybrid conductive adhesive materials studied by X-ray nano-tomography

    NASA Astrophysics Data System (ADS)

    Chen-Wiegart, Yu-Chen Karen; Figueroa-Santos, Miriam Aileen; Petrash, Stanislas; Garcia-Miralles, Jose; Wang, Jun

    2014-12-01

    Conductive adhesives are found favorable in a wide range of applications including a lead-free solder in micro-chips, flexible and printable electronics and enhancing the performance of energy storage devices. Composite materials comprised of metallic fillers and a polymer matrix are of great interest to be implemented as hybrid conductive adhesives. Here we investigated a cost-effective conductive adhesive material consisting of silver-coated copper as micro-fillers using synchrotron-based three-dimensional (3D) X-ray nano-tomography. The key factors affecting the quality and performance of the material were quantitatively studied in 3D on the nanometer scale for the first time. A critical characteristic parameter, defined as a shape-factor, was determined to yield a high-quality silver coating, leading to satisfactory performance. A `stack-and-screen' mechanism was proposed to elaborate such a phenomenon. The findings and the technique developed in this work will facilitate the future advancement of conductive adhesives to have a great impact in micro-electronics and other applications.Conductive adhesives are found favorable in a wide range of applications including a lead-free solder in micro-chips, flexible and printable electronics and enhancing the performance of energy storage devices. Composite materials comprised of metallic fillers and a polymer matrix are of great interest to be implemented as hybrid conductive adhesives. Here we investigated a cost-effective conductive adhesive material consisting of silver-coated copper as micro-fillers using synchrotron-based three-dimensional (3D) X-ray nano-tomography. The key factors affecting the quality and performance of the material were quantitatively studied in 3D on the nanometer scale for the first time. A critical characteristic parameter, defined as a shape-factor, was determined to yield a high-quality silver coating, leading to satisfactory performance. A `stack-and-screen' mechanism was proposed to

  12. Nanoleakage Evaluation of Posterior Teeth Restored with Low Shrinkable Resin Composite- An invitro Study

    PubMed Central

    Labib, Labib Mohamed; Nabih, Sameh Mahmoud

    2016-01-01

    Introduction The effect of nanoleakage on the integrity of resin–dentin bond has been in interest for long-term adhesion. Aim This study evaluated the nanoleakage in premolar teeth restored with low shrinkable resin composite. Materials and Methods A total of 40 human premolars were used for nanoleakage evaluation in this study. Each group was divided into four equal groups; Group A: using silorane with its adhesive system. Group B: using silorane with G-bond. Group C: using Filtek supreme composite with G-bond. Group D: using Filtek supreme composite with AdheSE adhesive. Nanoleakage analysed using Scaning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectrometery (EDX). Results The amount of silver present in hybrid layer depend on the adhesive used; this indicated different nanoleakage expressions in different adhesive systems. Filtek Z350 composite with G-bond showed clear silver uptake in both the adhesive and hybrid layer. Low shrinkable resin composite (silorane) with its adhesive system showed less silver penetration and slight silver peak on the elemental energy spectroscopy of energy dispersive X-Ray spectrometry (EDS) as compared to other samples. Conclusion Adhesives used between different groups, influence the location and degree of nanoleakage. There is difference in nanoleakage patterns between two-step and one-step adhesives and also among the one-step adhesives themselves.

  13. Temperature changes under demineralized dentin during polymerization of three resin-based restorative materials using QTH and LED units

    PubMed Central

    Mousavinasab, Sayed-Mostafa; Moharreri, Mohammadreza; Atai, Mohammad

    2014-01-01

    Objectives Light-curing of resin-based materials (RBMs) increases the pulp chamber temperature, with detrimental effects on the vital pulp. This in vitro study compared the temperature rise under demineralized human tooth dentin during light-curing and the degrees of conversion (DCs) of three different RBMs using quartz tungsten halogen (QTH) and light-emitting diode (LED) units (LCUs). Materials and Methods Demineralized and non-demineralized dentin disks were prepared from 120 extracted human mandibular molars. The temperature rise under the dentin disks (n = 12) during the light-curing of three RBMs, i.e. an Ormocer-based composite resin (Ceram. X, Dentsply DeTrey), a low-shrinkage silorane-based composite (Filtek P90, 3M ESPE), and a giomer (Beautifil II, Shofu GmbH), was measured with a K-type thermocouple wire. The DCs of the materials were investigated using Fourier transform infrared spectroscopy. Results The temperature rise under the demineralized dentin disks was higher than that under the non-demineralized dentin disks during the polymerization of all restorative materials (p < 0.05). Filtek P90 induced higher temperature rise during polymerization than Ceram.X and Beautifil II under demineralized dentin (p < 0.05). The temperature rise under demineralized dentin during Filtek P90 polymerization exceeded the threshold value (5.5℃), with no significant differences between the DCs of the test materials (p > 0.05). Conclusions Although there were no significant differences in the DCs, the temperature rise under demineralized dentin disks for the silorane-based composite was higher than that for dimethacrylate-based restorative materials, particularly with QTH LCU. PMID:25110638

  14. Effects of the Nd:YAG laser on amalgam dental restorative material: a preliminary study

    NASA Astrophysics Data System (ADS)

    Cernavin, Igor; Hogan, Sean P.

    1996-09-01

    The Nd:YAG laser has been marketed as an instrument for use on both hard and soft dental tissues. Its potential for use on hard tissues is limited but it may be the instrument of choice for use in certain soft tissue procedures. The aim of this study was to examine the effects of the Nd:YAG laser on amalgam restorations which frequently occur on tooth surfaces adjacent to areas of soft tissue which may be subjected to the laser. The amalgam used was Tytin. The laser firing was controlled by a computer and a constant repetition rate of 40 Hz was used. Energy per pulse was altered as follows, 30 mJ, 40 mJ, 60 mJ, 80 mJ, 120 mJ and 140 mJ. Exposure times of 0.05 sec, 0.125 sec, 0.25 sec, 0.5 sec, 1 sec, 2 sec, 3 sec, 4 sec, and 5 sec were used. The width of defect was measured using a Nikon measurescope with 10x magnification and it was established that the damage threshold lies between 0.125 sec and 0.25 sec for 30 mJ per pulse. The data was analyzed using a one way ANOVA statistical test. There was a significant correlation between the width of the defect and energy per pulse setting as well as exposure time. The findings indicate that amalgam restorations are prone to damage from inadvertent laser exposure and clinicians must take measures to protect such restorations during lasing of soft tissues.

  15. Treatment of traumatic injuries in the front teeth: restorative aspects in crown fractures.

    PubMed

    Dietschi, D; Jacoby, T; Dietschi, J M; Schatz, J P

    2000-10-01

    Crown fractures are the most common form of traumatic dental injuries encountered in permanent dentition. Restorative treatment modalities incorporate adhesive materials to effectively maintain function and aesthetics. While uncomplicated injuries of the enamel and/or dentin can be treated solely with adhesive procedures, complicated trauma that involves pulp exposure requires the incorporation of a multidisciplinary treatment approach. Fragment reattachment is facilitated by the utilization of bonding agents that enhance retention and aesthetics. This article discusses the application of provisional and permanent restorative options for the treatment of complications following traumatic injuries. PMID:11404871

  16. Comparative Evaluation of Sealing Ability of Four Different Restorative Materials Used as Coronal Sealants: An In Vitro Study

    PubMed Central

    Divya, K T; Satish, G; Srinivasa, T S; Reddy, Veera; Umashankar, K; Rao, B Mohan

    2014-01-01

    Background: The purpose of the present study was to evaluate and compare the sealing ability of glass ionomer cement (GIC), composite resin, gray mineral trioxide aggregate (GMTA) and white mineral trioxide aggregate (WMTA) when placed coronally as double - sealing material over gutta-percha in root canal treated teeth. Materials and Methods: A sample of 70 freshly extracted human single rooted teeth were cleaned, shaped and obturated with gutta-percha and AH Plus. The gutta-percha was reduced to a depth of 4 mm from the cemento enamel junction using hot plugger and standardized access cavities with 4 mm depth were prepared at the coronal ends of the roots. The specimens were randomly divided into four groups containing 15 teeth each depending on the restorations they received in the coronal cavity. A positive control group of five teeth received no restorative barrier over gutta-percha. All root surfaces were covered with two coats of nail varnish, leaving only the access openings uncovered except teeth in the negative control group, which were completely covered with nail varnish. All teeth were immersed in India ink, cleared and observed under stereomicroscope for the depth of dye penetration. Results: The results were tabulated and analyzed using Kruskal–Wallis test and multiple comparison between each group was carried out using Mann-Whitney test. The groups sealed with GMTA and WMTA showed least dye penetration than other groups and the difference was statistically significant. Highest dye penetration was seen with groups sealed with GIC and was statistically significant compared with other three groups. Conclusion: The results showed that the GMTA and WMTA provided significantly better coronal seal when compared to other two restorations. The composite resin also showed significantly better seal than the unsealed group and the group sealed GIC, which showed highest leakage that was equivalent to that of unsealed group. PMID:25214726

  17. Quantification of organic eluates from polymerized resin-based dental restorative materials by use of GC/MS.

    PubMed

    Michelsen, Vibeke Barman; Moe, Grete; Skålevik, Rita; Jensen, Einar; Lygre, Henning

    2007-05-01

    Residual monomers, additives and degradation products from resin-based dental restorative materials eluted into the oral cavity may influence the biocompatibility of these materials. Emphasis has been placed on studies addressing cytotoxic, genotoxic and estrogenic potential of these substances. A prerequisite for analyzing the potential of exposure to eluted compounds from dental materials is reliable quantification methods, both real time and accelerated measurements. The purpose of the present study was to quantify nine eluates; 2-hydroxyethyl methacrylate (HEMA), hydroquinone monomethyl ether (MEHQ), camphorquinone (CQ), butylated hydroxytoluene (BHT), ethyl 4-(dimethylamino)benzoate (DMABEE), triethylene glycoldimethacrylate (TEGDMA), trimethylolpropane trimethacrylate (TMPTMA), oxybenzone (HMBP) and drometrizole (TIN P) leaching from specimens of four commonly used resin-based dental materials in ethanol and an aqueous solution. All analyses were performed by use of GC/MS, each component was quantified separately and the results presented in microg mm(-2). This study has shown that elution from various materials differs significantly, not only in the types of eluates, but also regarding amounts of total and of single components. A high amount of HMBP, a UV stabilizer with potential estrogenic activity, was detected from one material in both solutions. PMID:17127109

  18. A comparative study of sliding wear of nonmetallic dental restorative materials with emphasis on micromechanical wear mechanisms.

    PubMed

    Dupriez, Nataliya Deyneka; von Koeckritz, Ann-Kristin; Kunzelmann, Karl-Heinz

    2015-05-01

    The purpose of this study is to investigate the in vitro tribological behavior of modern nonmetallic restorative materials. Specimen prepared of IPS e.max Press lithium disilicate glass ceramic, IPS Empress Esthetic leucite-reinforced glass ceramic, Everest ZS Blanks yttria-stabilized zirconia and Lava Ultimate composite were subjected to wear using a wear machine designed to simulate occlusal loads. The wear of the investigated materials and antagonists were evaluated by a three-dimensional surface scanner. The quantitative wear test results were used to compare and rank the materials. Specimens were divided into two groups with steatite and alumina antagonists. For each antagonist material an analysis of variance was applied. As a post hoc test of the significant differences, Tukey's honest significant difference test was used. With steatite antagonist: wear of zirconia < wear of leucite-reinforced ceramic < wear of lithium disilicate ceramic < wear of Lava Ultimate composite. No significant wear difference was found for steatite antagonist. The wear of IPS e.max Press and Lava Ultimate against hard alumina was found to be twice lower as compared to their wear when opposing to steatite. The differences were associated with materials mechanical properties (hardness and fracture toughness) and with materials microstructure. Wear mechanisms are discussed. PMID:25303041

  19. Critical factors affecting the 3D microstructural formation in hybrid conductive adhesive materials studied by X-ray nano-tomography.

    PubMed

    Chen-Wiegart, Yu-chen Karen; Figueroa-Santos, Miriam Aileen; Petrash, Stanislas; Garcia-Miralles, Jose; Wang, Jun

    2015-01-21

    Conductive adhesives are found favorable in a wide range of applications including a lead-free solder in micro-chips, flexible and printable electronics and enhancing the performance of energy storage devices. Composite materials comprised of metallic fillers and a polymer matrix are of great interest to be implemented as hybrid conductive adhesives. Here we investigated a cost-effective conductive adhesive material consisting of silver-coated copper as micro-fillers using synchrotron-based three-dimensional (3D) X-ray nano-tomography. The key factors affecting the quality and performance of the material were quantitatively studied in 3D on the nanometer scale for the first time. A critical characteristic parameter, defined as a shape-factor, was determined to yield a high-quality silver coating, leading to satisfactory performance. A 'stack-and-screen' mechanism was proposed to elaborate such a phenomenon. The findings and the technique developed in this work will facilitate the future advancement of conductive adhesives to have a great impact in micro-electronics and other applications. PMID:25474162

  20. Analytical tools for identification of non-intentionally added substances (NIAS) coming from polyurethane adhesives in multilayer packaging materials and their migration into food simulants.

    PubMed

    Félix, Juliana S; Isella, Francesca; Bosetti, Osvaldo; Nerín, Cristina

    2012-07-01

    Adhesives used in food packaging to glue different materials can provide several substances as potential migrants, and the identification of potential migrants and migration tests are required to assess safety in the use of adhesives. Solid-phase microextraction in headspace mode and gas chromatography coupled to mass spectrometry (HS-SPME-GC-MS) and ChemSpider and SciFinder databases were used as powerful tools to identify the potential migrants in the polyurethane (PU) adhesives and also in the individual plastic films (polyethylene terephthalate, polyamide, polypropylene, polyethylene, and polyethylene/ethyl vinyl alcohol). Migration tests were carried out by using Tenax(®) and isooctane as food simulants, and the migrants were analyzed by gas chromatography coupled to mass spectrometry. More than 63 volatile and semivolatile compounds considered as potential migrants were detected either in the adhesives or in the films. Migration tests showed two non-intentionally added substances (NIAS) coming from PU adhesives that migrated through the laminates into Tenax(®) and into isooctane. Identification of these NIAS was achieved through their mass spectra, and 1,6-dioxacyclododecane-7,12-dione and 1,4,7-trioxacyclotridecane-8,13-dione were confirmed. Caprolactam migrated into isooctane, and its origin was the external plastic film in the multilayer, demonstrating real diffusion through the multilayer structure. Comparison of the migration values between the simulants and conditions will be shown and discussed. PMID:22526644

  1. Effect of Fluoride-Releasing Adhesive Systems on the Mechanical Properties of Eroded Dentin.

    PubMed

    Guedes, Ana Paula Albuquerque; Moda, Mariana Dias; Suzuki, Thaís Yumi Umeda; Godas, André Gustavo de Lima; Sundfeld, Renato Herman; Briso, André Luiz Fraga; Santos, Paulo Henrique dos

    2016-01-01

    The aim of the study was to evaluate the effect of erosive pH cycling with solutions that simulate dental erosion on Martens hardness (HMV) and elastic modulus (Eit) of dentin restored with fluoride-releasing adhesive systems. Twenty-seven bovine dentin slabs were restored with three adhesive systems: Adper Single Bond 2 total-etch adhesive system, One Up Bond F and Clearfil SE Protect fluoride-containing self-etching adhesive systems. The restorations were made with Filtek Z250. The HMV and Eit values at distances of 10, 30, 50 and 70 µm from the interface were evaluated using a dynamic ultra microhardness tester before and after immersion in deionized water, citric acid and hydrochloric acid (n=9). Data were submitted to repeated-measures ANOVA and Fisher's PLSD tests (=0.05). After erosive cycling, HMV values of dentin decreased in all groups. For dentin restored with Adper Single Bond 2, the lowest values were found closer to the hybrid layer, while for One Up Bond F and Clearfil SE Protect, the values remained unaltered at all distances. For dentin restored with fluoride-releasing adhesive systems, a decrease in Eit was found, but after 30 µm this difference was not significant. The acid substances were able to alter HMV and Eit of the underlying dentin. For fluoride-releasing adhesives, the greater the distance from bonded interface, the lower the Eit values. The fluoride in One Up Bond F and Clearfil SE Protect was able to protect the underlying dentin closer to the materials. In this way, the fluoride from adhesive systems could have some positive effect in the early stages of erosive lesions. PMID:27058377

  2. Effect of Temperature-Sensitive Poloxamer Solution/Gel Material on Pericardial Adhesion Prevention: Supine Rabbit Model Study Mimicking Cardiac Surgery

    PubMed Central

    Kang, Hyun; Chung, Yoon Sang; Kim, Sang Wook; Choi, Geun Joo; Kim, Beom Gyu; Park, Suk Won; Seok, Ju Won; Hong, Joonhwa

    2015-01-01

    Objective We investigated the mobility of a temperature-sensitive poloxamer/Alginate/CaCl2 mixture (PACM) in relation to gravity and cardiac motion and the efficacy of PACM on the prevention of pericardial adhesion in a supine rabbit model. Methods A total of 50 rabbits were randomly divided into two groups according to materials applied after epicardial abrasion: PACM and dye mixture (group PD; n = 25) and saline as the control group (group CO; n = 25). In group PD, rabbits were maintained in a supine position with appropriate sedation, and location of mixture of PACM and dye was assessed by CT scan at the immediate postoperative period and 12 hours after surgery. The grade of adhesions was evaluated macroscopically and microscopically two weeks after surgery. Results In group PD, enhancement was localized in the anterior pericardial space, where PACM and dye mixture was applied, on immediate post-surgical CT scans. However, the volume of the enhancement was significantly decreased at the anterior pericardial space 12 hours later (P < .001). Two weeks after surgery, group PD had significantly lower macroscopic adhesion score (P = .002) and fibrosis score (P = .018) than did group CO. Inflammation score and expression of anti-macrophage antibody in group PD were lower than those in group CO, although the differences were not significant. Conclusions In a supine rabbit model study, the anti-adhesion effect was maintained at the area of PACM application, although PACM shifted with gravity and heart motion. For more potent pericardial adhesion prevention, further research and development on the maintenance of anti-adhesion material position are required. PMID:26580394

  3. Quantitative Assessment of Fluoride Release and Recharge Ability of Different Restorative Materials in Different Media: An in Vitro Study

    PubMed Central

    Pathak, Anuradha; Bajwa, Navroop Kaur; Sidhu, Haridarshan Singh

    2014-01-01

    Objective: To measure fluoride release and recharge ability of restorative materials in deionised water, artificial saliva and lactic acid. Materials and Methods: Pellets were prepared from GC2, Ketac N100 and Beautifil II. Each pellets were individually immersed in 10 ml deionised water, artificial saliva or lactic acid as per respective subgroup for 24 h and then elutes were collected. Specimens were reimmersed in respective container. Fluoride released was analysed after 24 h, 7th and 15th day. On 15th day all specimens were exposed to 1.23% APF gel and fluoride release in respective solution was measured on 16th, 22nd, 30th day. Result: Fluoride release was more after 24 h for all materials in all media then decrease gradually. GC2 shows more fluoride release than Ketac N100 at 24 hours and on 7th day but onwards Ketac N100 released significantly more fluoride. Beautifil II showed least fluoride release at all measured intervals in all media. Order of fluoride release in media was lactic acid > deionised water > artificial saliva for all materials. Conclusion: GICs are smart material which release more fluoride when environment become more acidic and also show tendency to recharge which helps clinically in caries risk children. PMID:25654027

  4. The Preservation and Restoration of Photographic Materials in Archives and Libraries: A RAMP Study with Guidelines.

    ERIC Educational Resources Information Center

    Hendriks, Klaus B.

    Intended for use by archivists, curators, and others responsible for the acquisition and preservation of documentary materials in photographic form, this publication describes the nature of photographic media and recommended conservation measures. It is noted that the major emphasis is on black-and-white photographic materials, with some…

  5. Prediction and diagnosis of clinical outcomes affecting restoration margins.

    PubMed

    Dennison, J B; Sarrett, D C

    2012-04-01

    The longevity of dental restorations is largely dependent on the continuity at the interface between the restorative material and adjacent tooth structure (the restoration margin). Clinical decisions on restoration repair or replacement are usually based upon the weakest point along that margin interface. Physical properties of a restorative material, such as polymerisation shrinkage, water sorption, solubility, elastic modulus and shear strength, all have an effect on stress distribution and can significantly affect margin integrity. This review will focus on two aspects of margin deterioration in the oral environment: the in vitro testing of margin seal using emersion techniques to simulate the oral environment and to predict clinical margin failure and the relationship between clinically observable microleakage and secondary caries. The many variables associated with in vitro testing of marginal leakage and the interpretation of the data are presented in detail. The most recent studies of marginal leakage mirror earlier methodology and lack validity and reliability. The lack of standardised testing procedures makes it impossible to compare studies or to predict the clinical performance of adhesive materials. Continual repeated in vitro studies contribute little to the science in this area. Clinical evidence is cited to refute earlier conclusions that clinical microleakage (penetrating margin discoloration) leads to caries development and is an indication for restoration replacement. Margin defects, without visible evidence of soft dentin on the wall or base of the defect, should be monitored, repaired or resealed, in lieu of total restoration replacement. PMID:22066463

  6. Novel Dental Restorative Materials having Low Polymerization Shrinkage Stress via Stress Relaxation by Addition-Fragmentation Chain Transfer

    PubMed Central

    Park, Hee Young; Kloxin, Christopher J.; Abuelyaman, Ahmed S.; Oxman, Joe D.; Bowman, Christopher N.

    2012-01-01

    Objectives To produce a reduced stress dental restorative material while simultaneously maintaining excellent mechanical properties, we have incorporated an allyl sulfide functional group into norbornene-methacrylate comonomer resins. We hypothesize that the addition-fragmentation chain transfer (AFCT) enabled by the presence of the allyl sulfide relieves stress in these methacrylate-based systems while retaining excellent mechanical properties owing to the high glass transition temperature of norbornene-containing resins. Methods An allyl sulfide-containing dinorbornene was stoichiometrically formulated with a ring-containing allyl sulfide-possessing methacrylate. To evaluate the stress relaxation effect as a function of the allyl sulfide concentration, a propyl sulfide-based dinorbornene, not capable of addition-fragmentation, was also formulated with the methacrylate monomer. Shrinkage stress, the glass transition temperature and the elastic modulus were all measured. The composite flexural strength and modulus were also measured. ANOVA (CI 95%) was conducted to determine differences between the means. Results Increasing the allyl sulfide content in the resin dramatically reduces the final stress in the norbornene-methacrylate systems. Both norbornene-methacrylate resins demonstrated almost zero stress (more than 96% stress reduction) compared with the conventional BisGMA/TEGDMA 70/30 wt% control. Mechanical properties of the allyl sulfide-based dental composites were improved to the point of being statistically indistinguishable from the control BisGMA-TEGDMA by changing the molar ratio between the methacrylate and norbornene functionalities. Significance The allyl sulfide-containing norbornene-methacrylate networks possessed super-ambient Tg, and demonstrated significantly lower shrinkage stress when compared with the control (BisGMA/TEGDMA 70 to 30 wt%). Although additional development remains, these low stress materials exhibit excellent mechanical

  7. Effect of chronic and subchronic organic solvents exposure on balance control of workers in plant manufacturing adhesive materials.

    PubMed

    Herpin, Guillaume; Gargouri, Imed; Gauchard, Gérome C; Nisse, Catherine; Khadhraoui, Moncef; Elleuch, Boubaker; Zmirou-Navier, Denis; Perrin, Philippe P

    2009-02-01

    High-level occupational exposure to volatile organic solvents may elicit neurotoxic effects, especially on central and peripheral structures involved in balance ability. Studies on balance control in relation with exposure levels close to the threshold limit values are scarce. This study aimed to assess the neurotoxic effects of chronic and subchronic exposure to organic solvents among workers in plant manufacturing adhesive materials. Balance control was evaluated in 18 subjects, mainly exposed to n-hexane and toluene, with current median exposure levels of 222 and 102 mg/m(3), respectively, and a median exposure duration of 21 years, and in 32 nonexposed controls, using posturography tests with and without sensory conflicting situations. Tests were undergone at the beginning of the work shift (chronic exposure) following a week end, and after 72 h (subchronic exposure). Balance control performance was lower in chronically exposed workers compared to controls, and got worse after subchronic exposure, particularly during situations, where vestibular information was important. Our study suggests that a low-level and prolonged exposure to volatile organic solvents, mainly n-hexane and toluene, in the workplace is associated with deleterious central effects involved in postural regulation. This neurotoxicity is characterized by difficulties to use the most relevant information to control balance, leading to altered management of sensory conflicting situations. PMID:19384580

  8. [Investigation of characteristic microstructures of adhesive interface in wood/bamboo composite material by synchrotron radiation X-ray phase contrast microscopy].

    PubMed

    Peng, Guan-Yun; Wang, Yu-Rong; Ren, Hai-Qing; Yang, Shu-Min; Ma, Hong-Xia; Xie, Hong-Lan; Deng, Biao; Du, Guo-Hao; Xiao, Ti-Qiao

    2013-03-01

    Third-generation synchrotron radiation X-ray phase-contrast microscopy(XPCM)can be used for obtaining image with edge enhancement, and achieve the high contrast imaging of low-Z materials with the spatial coherence peculiarity of X-rays. In the present paper, the characteristic microstructures of adhesive at the interface and their penetration in wood/bamboo composite material were investigated systematically by XPCM at Shanghai Synchrotron Radiation Facility (SSRF). And the effect of several processing techniques was analyzed for the adhesive penetration in wood/bamboo materials. The results show that the synchrotron radiation XPCM is expected to be one of the important precision detection methods for wood-based panels. PMID:23705464

  9. Therapeutic polymers for dental adhesives: Loading resins with bio-active components

    PubMed Central

    Imazato, Satoshi; Ma, Sai; Chen, Ji-hua; Xu, Hockin H.K.

    2014-01-01

    Objectives Many recent adhesives on the market exhibit reasonable clinical performance. Future innovations in adhesive materials should therefore seek out novel properties rather than simply modifying existing technologies. It is proposed that adhesive materials that are “bio-active” could contribute to better prognosis of restorative treatments. Methods This review examines the recent approaches used to achieve therapeutic polymers for dental adhesives by incorporating bio-active components. A strategy to maintain adhesive restorations is the focus of this paper. Results Major trials on therapeutic dental adhesives have looked at adding antibacterial activities or remineralization effects. Applications of antibacterial resin monomers based on quaternary ammonium compounds have received much research attention, and the loading of nano-sized bioactive particles or multiple ion-releasing glass fillers have been perceived as advantageous since they are not expected to influence the mechanical properties of the carrier polymer. Significance The therapeutic polymer approaches described here have the potential to provide clinical benefits. However, not many technological applications in this category have been successfully commercialized. Clinical evidence as well as further advancement of these technologies can be a driving force to make these new types of materials clinically available. PMID:23899387

  10. Focal adhesions in osteoneogenesis

    PubMed Central

    Biggs, M.J.P; Dalby, M.J

    2010-01-01

    As materials technology and the field of tissue engineering advances, the role of cellular adhesive mechanisms, in particular the interactions with implantable devices, becomes more relevant in both research and clinical practice. A key tenet of medical device technology is to use the exquisite ability of biological systems to respond to the material surface or chemical stimuli in order to help develop next-generation biomaterials. The focus of this review is on recent studies and developments concerning focal adhesion formation in osteoneogenesis, with an emphasis on the influence of synthetic constructs on integrin mediated cellular adhesion and function. PMID:21287830

  11. High temperature adhesives

    NASA Technical Reports Server (NTRS)

    St.clair, Terry L.

    1991-01-01

    The aerospace and electronics industries have an ever increasing need for higher performance materials. In recent years, linear aromatic polyimides have been proven to be a superior class of materials for various applications in these industries. The use of this class of polymers as adhesives is continuing to increase. Several NASA Langley developed polyimides show considerable promise as adhesives because of their high glass transition temperatures, thermal stability, resistance to solvents/water, and their potential for cost effective manufacture.

  12. Migration of odorous compounds from adhesives used in market samples of food packaging materials by chromatography olfactometry and mass spectrometry (GC-O-MS).

    PubMed

    Vera, Paula; Canellas, Elena; Nerín, Cristina

    2014-02-15

    Adhesives are commonly used in the manufacture of multilayer food packaging materials. Although they are not in direct contact with the packed food, their compounds may migrate from the adhesive through the substrates to the food. The aim of this work is to determine the migrant concentration in order to evaluate the possible human risk and also to determine if this migration could affect the organoleptic properties of packed food. For this purpose, a total of 12 market samples of multilayer materials (laminates) for packaging dry food (tomatoes, cakes, cookies, breadcrumbs, flour or salt) or fresh food (pizza and pastry) produced with 5 different adhesives were analysed by GC-O-MS. A total of 25 different compounds from adhesives were detected in these laminates. Seventy-six percentage of these compounds migrated into a dry food simulant (Tenax®). Furthermore, compounds with concentrations below the MS detection limit were detected by sniffers with a high modified frequency (MF%). Acetic acid, butyric acid and cyclohexanol with vinegar, cheese and camphor odours were the most abundant compounds. All migration data were below the specific migration limits (SML) and threshold toxicological concern (TTC) recommended values according to the Cramer classification. PMID:24128473

  13. Chipping fracture resistance of dental CAD/CAM restorative materials: Part 2. Phenomenological model and the effect of indenter type

    PubMed Central

    Quinn, G.D.; Giuseppetti, A.A.; Hoffman, K.H.

    2014-01-01

    The edge chipping resistances of six CAD/CAM dental restoration materials are analyzed and correlated to other mechanical properties. A new quadratic relationship that is based on a phenomenological model is presented. Objective The purpose of this study was to further analyze the edge chipping resistance of the brittle materials evaluated in Part 1. One objective was to determine why some force-distance trends were linear and others were nonlinear. A second objective was to account for differences in chipping resistance with indenter type. Methods Edge chipping experiments were conducted with different indenters, including some custom-made sharp conical indenters. A new force – distance quadratic expression was correlated to the data and compared to the linear and power law trends. Results The new quadratic function was an excellent fit in every instance. It can account for why some materials can be fit by a linear trend, while others can be fit by the power law trend. The effects of indenter type are accounted for variations in crack initiation and by the wedging stresses once an indentation hole is created. Significance The new quadratic force – edge distance function can be used with edge chipping data for all brittle materials, not just those evaluated in this study. The data trends vary from linear to nonlinear depending upon the material’s hardness, fracture toughness, and elastic modulus. PMID:24685179

  14. Suspension of bed material over sand bars in the Lower Mississippi River and its implications for Mississippi delta environmental restoration

    NASA Astrophysics Data System (ADS)

    Ramirez, Michael T.; Allison, Mead A.

    2013-06-01

    specific pathways for sand transport in the lower reaches of large rivers, including the Mississippi, is a key for addressing multiple significant geologic problems, such as delta building and discharge to the oceans, and for environmental restoration efforts in deltaic environments threatened by rising sea levels. Field studies were performed in the Mississippi River 75-100 km upstream of the Gulf of Mexico outlet in 2010-2011 to examine sand transport phenomena in the tidally affected river channel over a range of discharges. Methods included mapping bottom morphology (multibeam sonar), cross-sectional and longitudinal measurements of water column velocity and acoustic backscatter, suspended sediment sampling, and channel-bed sampling. Substantial interaction was observed between the flow conditions in the river (boundary shear stress), channel-bed morphology (size and extent of sandy bedforms), and bed material sand transport (quantity, transport mode, and spatial distribution). A lateral shift was observed in the region of maximum bed material transport from deep to shallow areas of subaqueous sand bars with increasing water discharge. Bed material was transported both in traction and in suspension at these water discharges, and we posit that the downriver flux of sand grains is composed of both locally- and drainage basin-sourced material, with distinct transport pathways and relations to flow conditions. We provide suggestions for the optimal design and operation of planned river diversion projects.

  15. Abdominal Adhesions

    MedlinePlus

    ... Abdominal Adhesions 1 Ward BC, Panitch A. Abdominal adhesions: current and novel therapies. Journal of Surgical Research. 2011;165(1):91– ... are abdominal adhesions and intestinal obstructions ... generally do not require treatment. Surgery is the only way to treat abdominal ...

  16. Microleakage of silorane- and methacrylate-based class V composite restorations.

    PubMed

    Krifka, Stephanie; Federlin, Marianne; Hiller, Karl-Anton; Schmalz, Gottfried

    2012-08-01

    The marginal integrity of class V restorations in a silorane- and a group of methacrylate-based composite resins with varying viscosities was tested in the present study. Different adhesives (OptiBond FL, KerrHawe; AdheSE One, Vivadent; or Silorane System Adhesive, 3M ESPE) were applied to 168 standardized class V cavities. The cavities (n = 12) were filled with a wide range of different viscous composite resins: Filtek Silorane, 3M ESPE; els and els flow, Saremco; Tetric EvoCeram and Tetric EvoFlow, Vivadent; Grandio, Voco; and Ultraseal XT Plus, Ultradent. Microleakage of the restoration was assessed by dye penetration (silver staining) on multiple sections with and without thermocycling and mechanical loading (TCML: 5,000 × 5-55°C; 30 s/cycle; 500,000 × 72.5 N, 1.6 Hz). Data were statistically analyzed with the Mann-Whitney U test and the Error Rates Method (ERM). The silorane-based composite resin yielded the lowest dye penetration after TCML. Microleakage of methacrylate-based composite restorations, in general (ERM), was statistically significantly influenced by the adhesive system, Moreover, dye penetration at enamel margins was significantly lower than dye penetration at dentin margins. The chemical basis of composite resins and adjacent tooth substance seems to strongly influence marginal sealing of class V restorations for methacrylate-based materials. Moreover, the steps of dental adhesives used affected marginal integrity. The silorane-based composite resin evaluated in the present study exhibits the best marginal seal. The three-step adhesive yielded better marginal sealing than the one-step adhesive for methacrylate-based class V composite restorations. PMID:21947906

  17. Switchable bio-inspired adhesives

    NASA Astrophysics Data System (ADS)

    Kroner, Elmar

    2015-03-01

    Geckos have astonishing climbing abilities. They can adhere to almost any surface and can run on walls and even stick to ceilings. The extraordinary adhesion performance is caused by a combination of a complex surface pattern on their toes and the biomechanics of its movement. These biological dry adhesives have been intensely investigated during recent years because of the unique combination of adhesive properties. They provide high adhesion, allow for easy detachment, can be removed residue-free, and have self-cleaning properties. Many aspects have been successfully mimicked, leading to artificial, bio-inspired, patterned dry adhesives, and were addressed and in some aspects they even outperform the adhesion capabilities of geckos. However, designing artificial patterned adhesion systems with switchable adhesion remains a big challenge; the gecko's adhesion system is based on a complex hierarchical surface structure and on advanced biomechanics, which are both difficult to mimic. In this paper, two approaches are presented to achieve switchable adhesion. The first approach is based on a patterned polydimethylsiloxane (PDMS) polymer, where adhesion can be switched on and off by applying a low and a high compressive preload. The switch in adhesion is caused by a reversible mechanical instability of the adhesive silicone structures. The second approach is based on a composite material consisting of a Nickel- Titanium (NiTi) shape memory alloy and a patterned adhesive PDMS layer. The NiTi alloy is trained to change its surface topography as a function of temperature, which results in a change of the contact area and of alignment of the adhesive pattern towards a substrate, leading to switchable adhesion. These examples show that the unique properties of bio-inspired adhesives can be greatly improved by new concepts such as mechanical instability or by the use of active materials which react to external stimuli.

  18. Reduced Zeta potential through use of cationic adhesion promoter for improved resist process performance and minimizing material consumption

    NASA Astrophysics Data System (ADS)

    Hodgson, Lorna; Thompson, Andrew

    2012-03-01

    This paper presents the results of a non-HMDS (non-silane) adhesion promoter that was used to reduce the zeta potential for very thin (proprietary) polymer on silicon. By reducing the zeta potential, as measured by the minimum sample required to fully coat a wafer, the amount of polymer required to coat silicon substrates was significantly reduced in the manufacture of X-ray windows used for high transmission of low-energy X-rays. Moreover, this approach used aqueous based adhesion promoter described as a cationic surface active agent that has been shown to improve adhesion of photoresists (positive, negative, epoxy [SU8], e-beam and dry film). As well as reducing the amount of polymer required to coat substrates, this aqueous adhesion promoter is nonhazardous, and contains non-volatile solvents.

  19. Biologically engineered protein-graft-poly(ethylene glycol) hydrogels: A cell-adhesive and plasmin-degradable biosynthetic material for tissue repair

    NASA Astrophysics Data System (ADS)

    Halstenberg, Sven

    2002-01-01

    The goal of the research presented in this dissertation was to create a biomimetic artificial material that exhibits functions of extracellular matrix relevant for improved nerve regeneration. Neural adhesion peptides were photoimmobilized on highly crosslinked poly(ethylene glycol)-based substrates that were otherwise non-adhesive. Neurons adhered in two-dimensional patterns for eleven hours, but no neurites extended. To enable neurite extension and nerve regeneration in three dimensions, and to address the need for specifically cell adhesive and cell degradable materials for clinical applications in tissue repair in general, an artificial protein was recombinantly expressed and purified that consisted of a repeating amino acid sequence based on fibrinogen and anti-thrombin III. The recombinant protein contained integrin-binding RGD sites, plasmin degradation sites, heparin binding sites, and six thiol-containing cysteine residues as grafting sites for poly(ethylene glycol) diacrylate via Michael-type conjugate addition. The resulting protein-graft-poly(ethylene glycol)acrylates were crosslinked by photopolymerization to form hydrogels. Although three-dimensional, RGD mediated and serine protease-dependent ingrowth of human fibroblasts into protein-graft-poly(ethylene glycol) hydrogels occurred, only surface neurite outgrowth was observed from chick dorsal root ganglia. Axonal outgrowth depended on the concentration of matrix-bound heparin, suggesting that improved mechanical strength of the hydrogels and possible immobilization of neuroactive factors due to the presence of heparin promoted neurite outgrowth. Together, the above results show that specific biological functions can be harnessed by protein-graft-poly(ethylene glycol) hydrogels to serve as matrices for tissue repair and regeneration. In particular, the two design objectives, specific cell adhesion and degradability by cell-associated proteases, were fulfilled by the material. In the future, this and

  20. Influence of different composite materials and cavity preparation designs on the fracture resistance of mesio-occluso-distal inlay restoration.

    PubMed

    Tekçe, Neslihan; Pala, Kansad; Demirci, Mustafa; Tuncer, Safa

    2016-01-01

    The aim of the study to evaluate the fracture resistance of a computer-aided design/computer-aided manufacturing (CAD/CAM) and three indirect composite materials for three different mesio-occluso-distal (MOD) inlay cavity designs. A total of 120 mandibular third molar were divided into three groups: (G1) non-proximal box, (G2) 2-mm proximal box, and (G3) 4-mm proximal box. Each cavity design received four composite materials: Estenia, Epricord (Kuraray, Japan), Tescera (Bisco, USA), and Cerasmart CAD/CAM blocks (GC, USA). The specimens were subjected to a compressive load at a crosshead speed of 1 mm/min. The data was analyzed using the two-way analysis of variance and Bonferroni post hoc test (p<0.05). Estenia exhibited significantly higher fracture strength than Epricord and Cerasmart in G1. In G2 and G3, there was no significant difference among the four materials. Using a non-proximal box design for the cavity can improve the fracture resistance of the inlay restoration. PMID:27252011

  1. Effect of fibril shape on adhesive properties

    NASA Astrophysics Data System (ADS)

    Soto, Daniel; Hill, Ginel; Parness, Aaron; Esparza, Noé; Cutkosky, Mark; Kenny, Tom

    2010-08-01

    Research into the gecko's adhesive system revealed a unique architecture for adhesives using tiny hairs. By using a stiff material (β-keratin) to create a highly structured adhesive, the gecko's system demonstrates properties not seen in traditional pressure-sensitive adhesives which use a soft, unstructured planar layer. In contrast to pressure sensitive adhesives, the gecko adhesive displays frictional adhesion, in which increased shear force allows it to withstand higher normal loads. Synthetic fibrillar adhesives have been fabricated but not all demonstrate this frictional adhesion property. Here we report the dual-axis force testing of single silicone rubber pillars from synthetic adhesive arrays. We find that the shape of the adhesive pillar dictates whether frictional adhesion or pressure-sensitive behavior is observed. This work suggests that both types of behavior can be achieved with structures much larger than gecko terminal structures. It also indicates that subtle differences in the shape of these pillars can significantly influence their properties.

  2. Restoring marsh elevation in a rapidly subsiding salt marsh by thin-layer deposition of dredged material

    USGS Publications Warehouse

    Ford, M.A.; Cahoon, D.R.; Lynch, J.C.

    1999-01-01

    Thin-layer deposition of dredged material on coastal marsh by means of high-pressure spray dredging (Jet-Spray??2) technology has been proposed as a mechanism to minimize wetland impacts associated with traditional bucket dredging technologies and to restore soil elevations in deteriorated marshes of the Mississippi River delta. The impact of spray dredging on vegetated marsh and adjacent shallow-water habitat (formerly vegetated marsh that deteriorated to open water) was evaluated in a 0.5-ha Spartina alterniflora-dominated salt marsh in coastal Louisiana. The thickness of dredged sediment deposits was determined from artificial soil marker horizons and soil elevation change was determined from sedimentation-erosion tables (SET) established prior to spraying in both sprayed and reference marshes. The vertical accretion and elevation change measurements were made simultaneously to allow for calculation of shallow (~5 m depth) subsidence (accretion minus elevation change). Measurements made immediately following spraying in July 1996 revealed that stems of S. alterniflora were knocked down by the force of the spray and covered with 23 mm of dredged material. Stems of S. alterniflora soon recovered, and by July 1997 the percent cover of S. alterniflora had increased three-fold over pre-project conditions. Thus, the layer of dredged material was thin enough to allow for survival of the S. alterniflora plants, with no subsequent colonization by plant species typical of higher marsh zones. By February 1998, 62 mm of vertical accretion accumulated at this site, and little indication of disturbance was noted. Although not statistically significant, soil elevation change was greater than accretion on average at both the spray and reference marshes, suggesting that subsurface expansion caused by increased root biomass production and/or pore water storage influence elevation in this marsh region. In the adjacent shallow water pond, 129 mm of sediment was deposited in July

  3. RECYCLED WASTE-BASED CEMENT COMPOSITE PATCH MATERIALS FOR RAPID/PERMANENT ROAD RESTORATION.

    SciTech Connect

    SUGAMA,T.

    2001-07-31

    Over the past year, KeySpan Energy sponsored a research program at Brookhaven National Laboratory (BNL) aimed at recycling boiler ash (BA) and waste water treatment sludge (WWTS) byproducts generated from Keyspan's power stations into potentially useful materials, and at reducing concurrent costs for their disposal. Also, KeySpan has an interest in developing strategies to explicitly integrate industrial ecology and green chemistry. From our collaborative efforts with Keyspan (Diane Blankenhom Project Manager, and Kenneth Yager), we succeeded in recycling them into two viable products; Pb-exchange adsorbents (PEAs), and high-performance cements (HpCs). These products were made from chemically bonded cement and ceramic (CBC) materials that were synthesized through two-step chemical reaction pathways, acid-base and hydration. Using this synthesis technology, both the WWTS and BA served in acting as solid base reactants, and sodium polyphosphate, [-(-NaPO{sub 3}-)-{sub n}], known as an intermediator of fertilizer, was employed as the acid solution reactant. In addition, two commercial cement additives, Secar No. 51 calcium aluminate cement (CAC) and Type I calcium silicate cement (CSC), were used to improve mechanical behavior and to promote the rate of acid-base reaction of the CBC materials.

  4. Environmentally compliant adhesive joining technology

    SciTech Connect

    Tira, J.S.

    1996-08-01

    Adhesive joining offers one method of assembling products. Advantages of adhesive joining/assembly include distribution of applied forces, lighter weight, appealing appearance, etc. Selecting environmentally safe adhesive materials and accompanying processes is paramount in today`s business climate if a company wants to be environmentally conscious and stay in business. Four areas of adhesive joining (adhesive formulation and selection, surface preparation, adhesive bonding process, waste and pollution generation/cleanup/management) all need to be carefully evaluated before adhesive joining is selected for commercial as well as military products. Designing for six sigma quality must also be addressed in today`s global economy. This requires material suppliers and product manufacturers to work even closer together.

  5. Influence of filler existence on microleakage of a self-etch adhesive system

    PubMed Central

    Mirmohammadi, H; Khosravi, K; Kashani, K; Kleverlaan, CJ; Feilzer, AJ

    2014-01-01

    Aim: This study evaluated the effect of filler existence in self-etch adhesive resin on the marginal leakage of a class V restoration. Materials and Methods: Class V cavities were prepared and restored with a resin composite on the buccal surfaces of 48 premolars lined with unfilled or filled adhesives (n = 24). After thermo cycling, teeth in each group were divided to two subgroups (n = 12), specimens of the first subgroup were incubated for 24 h in distilled water at 37°C, and for the second group three months in the same condition. Specimens were placed in 50% silver nitrate for 24 h at 37°C, and then were cut buccolingually 1 mm thick. Dye penetration was measured using a stereomicroscope and scaled from 0 to 5 in a blind method. SEM images were made to evaluate the dentin-adhesive interfaces. Collected data were analyzed using the nonparametric Kruskal-Wallis and Mann-Whitney U-tests at a significant level of P<0.05. Results: There was no significant difference between microleakage of filled and unfilled adhesive at 24 h and 3 months (P<0.05). There was a significant difference in cervical microleakage between 24 h and 3 months, which was independ on filler load of the adhesive (P<0.001). In contrast, there was no significant difference in occlusal microleakage between 24 h and 3 months and the cervical microleakage was significantly higher than occlusal microleakage after 3 months. SEM images reveald that unfilled adhesive infiltrate slightly better than filled adhesive. Conclusion: The application of filler particles in a self etch adhesive system had no influence on marginal leakage at both the enamel and dentin margins. While the unfilled adhesive infiltrate better than the filled adhesive, its long term performance is not promising. PMID:24778517

  6. Effect of microleakage and fluoride on enamel-dentine demineralization around restorations.

    PubMed

    Cenci, M S; Tenuta, L M A; Pereira-Cenci, T; Del Bel Cury, A A; ten Cate, J M; Cury, J A

    2008-01-01

    There is no consensus about an association between microleakage and secondary caries, especially considering the presence of fluoride (F) at the tooth/restoration interface. Thus, a randomized, double-blind, crossover study was carried out to evaluate in situ the effect of microleakage on caries around enamel-dentine restorations in the presence of F from dental materials or dentifrice, either alone or in combination. In 4 phases of 14 days each, 14 volunteers wore palatal devices containing dental slabs restored with composite resin (CR) or resin-modified glass ionomer cement (GI). Restorations were made without leakage (L-), following the recommended adhesive procedures, or with leakage (L+), in the absence of adhesive procedures. Plaque-like biofilm (PLB) was left to accumulate on the restored slabs, which were exposed extraorally to a 20% sucrose solution 10x/day. The volunteers used a non-F (NF) or an F (FD) dentifrice 3x/day, depending on the experimental phase. No differences were found between L+ or L- restorations (p > 0.05). Higher demineralization in both enamel and dentine around CR restorations was observed under NF (p < 0.05). F concentration was higher in the fluid of PLB exposed to FD or formed onto GI restoration (p < 0.05). These results suggest that while microleakage does not affect caries development, GI or FD may maintain increased F levels in the PLB, thereby decreasing caries progression. PMID:18753749

  7. The optimizing designing of bi-material micro cantilever with adhesive layer in between and its application in an uncooled MEMS IR FPA

    NASA Astrophysics Data System (ADS)

    Zhang, Xia; Jiao, Bin-bin; Chen, Da-peng; Ye, Tian-chun

    2009-07-01

    Bi-material cantilever is an important basic structure in MEMS device. Most of the materials with thermal property fit for bi-material are not adhering together steadily. An adhesive layer in between is needed. In this paper, based on the thermal stress and combined deformation in Mechanics of Materials, a model related to the physics properties, structure dimension, and the tilt angle caused by thermal stress is set up. A research of how to select the materials and how to determinate the thickness and other size of a bi-material cantilever is carry out by this model, further more, an optic read out IR image chip pixel is designed that shows this model is simple and practical.

  8. Effects of Protective Resin Coating on the Surface Roughness and Color Stability of Resin-Based Restorative Materials

    PubMed Central

    Tüzüner, Tamer; Korkmaz, Fatih Mehmet; Baygın, Özgül; Bağış, Yıldırım Hakan

    2014-01-01

    The aim of this study was to evaluate the effects of nanofilled protective resin coating (RC) on the surface roughness (Ra) and color stability (ΔE) of resin-based restorative materials (RM) (compomer (C), nanofilled composite (NF), and microhybrid composite (MH)) after being submitted to the ultraviolet aging (UV) method. Thirty-six specimens were prepared (n = 6 for each group). The Ra and (ΔE) values and SEM images were obtained before and after UV. Significant interactions were found among the RM-RC-UV procedures for Ra (P < 0.001). After the specimens were submitted to UV, the Ra values were significantly increased, regardless of the RC procedure (with RC; P < 0.01 for all, without RC; C (P < 0.01), NF (P < 0.001), and MH (P < 0.001)) for each RM. Significant interactions were found between the RM-RC (P < 0.001) procedures for the ΔE values. The ΔE values were increased in each group after applying the RC procedures (P < 0.001). Protective RC usage for RM could result in material-related differences in Ra and ΔE as with used UV method. PMID:25162066

  9. FTIR investigation of monomer polymerisation and polyacid neutralisation kinetics and mechanisms in various aesthetic dental restorative materials.

    PubMed

    Young, A M; Rafeeka, S A; Howlett, J A

    2004-02-01

    Diamond ATR FTIR has been used to quantify light catalysed polymerisation and polyacid neutralisation rates in various glass ionomer cements (GIC), resin-modified GICs (RMGIC) and compomers. At 150s after the start of light exposure, levels of methacrylate polymerisation on the lower surfaces of 1mm thick specimens were 97% and 98% for the RMGIC, Vitremer and Fuji II LC and 47% and 37% for the compomers, Compoglass and Dyract. After light exposure, polymerisation rates for the compomers decreased linearly with inverse time. By 50,000s Compoglass and Dyract were 62% and 51% polymerised. Initial rate of polyacid neutralisation in the GIC Shofu HIFI was 0.32 times that of Fuji IX GIC. Those in Vitremer, Fuji II LC, Compoglass and Dyract were 0.16, 0.09, 0.004 and 0.004 times that of Fuji IX. Excluding short initial periods, log of neutralisation rates decreased linearly with log-time. Average gradients were -1.35 for the GIC, -0.80 for the RMGIC and -0.59 for the compomers. By 50,000s, polyacid salt concentrations for the RMGIC and compomers were 0.41 and 0.016 times that of the GIC. Reaction mechanisms have been discussed and used to help interpret material mechanical properties, fluoride release rates and adhesion to tooth structure. PMID:14609671

  10. Longevity of posterior composite restorations: a systematic review and meta-analysis.

    PubMed

    Opdam, N J M; van de Sande, F H; Bronkhorst, E; Cenci, M S; Bottenberg, P; Pallesen, U; Gaengler, P; Lindberg, A; Huysmans, M C D N J M; van Dijken, J W

    2014-10-01

    The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years' follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces. PMID:25048250

  11. Critic appraisal. Postoperative sensitivity with indirect restorations.

    PubMed

    Farias, David; Walter, Ricardo; Swift, Edward J

    2014-01-01

    Postoperative sensitivity is characterized by short and sharp pain, and often experienced after cementation of indirect restorations. Factors associated with the occurrence of post-cementation sensitivity include type of cement, removal of smear layer by acid-etching, aggressive tooth preparation, inadequate provisional restorations, and patient's age. Its prevention is based on either interfering with mechanoreceptor activity or occluding the dentinal tubules. Regarding the latter, application of dentin desensitizers may be effective for blocking the tubules and significantly reducing dentin permeability and consequently postoperative sensitivity. This Critical Appraisal will present available clinical data where traditional materials such as zinc phosphate and glass ionomer cements (GIC) as well as self-adhesive resin-based cements were used. PMID:24761824

  12. Adsorption of parotid saliva proteins and adhesion of Streptococcus mutans ATCC 21752 to dental fiber-reinforced composites.

    PubMed

    Tanner, Johanna; Carlén, Anette; Söderling, Eva; Vallittu, Pekka K

    2003-07-15

    The use of fiber-reinforced composites (FRC) in dentistry has increased during recent years. In marginal areas of crowns and removable partial dentures the fibers may become exposed and come into contact with oral tissues, saliva, and microbes. To date, few articles have been published on oral microbial adhesion to FRCs. The aim of this study was to compare different FRCs, their components, and conventional restorative materials with respect to S. mutans ATCC 21752 adhesion and adsorption of specific S. mutans binding proteins. Surface roughness of the materials was also determined. Four different FRCs, a restorative composite, and a high-leucite ceramic material were studied. Polyethylene FRC was found to be significantly rougher than all other materials. Aramid FRC also showed higher surface roughness in comparison with all materials but polyethylene FRC. Without a saliva pellicle, adhesion of S. mutans coincided with surface roughness and polyethylene and aramid FRC promoted S. mutans adhesion better than the other smoother materials. In the presence of salivary pellicle, ceramic and polyethylene FRC bound more bacteria than the other materials studied. Higher quantities of S. mutans binding proteins in the pellicles may in part account for the higher S. mutans adhesion to saliva-coated ceramic and polyethylene FRC. PMID:12808599

  13. Distribution of calcium ions at the interface between resin bonding materials and tooth dentin. Use of commercially available adhesive systems.

    PubMed

    Hanaizumi, Y; Maeda, T; Takano, Y

    1998-01-01

    It has been proposed that calcium ions play a key role in chemical (chelate) binding between the adhesive resin and dentin surface. However, no data is available concerning how calcium ions are distributed at the binding sites. The aim of this study is to demonstrate calcium ions at the resin-dentin interface by means of X-ray microanalysis and calcium ion-sensitive histochemical staining. The dentin surface in human teeth was ground by use of 240 grit silicon carbide abrasive paper under running water and treated with the dentin-primer and adhesive resin in Clearfil Liner Bond System or IMPERVA Bond System according to the manufacturer's instructions. After removing dentin matrix and isolating adhesive resin by the KOH-digestion method, one half of the samples were processed for scanning electron microscopy. The rest were embedded in Epon 812 and processed either for glyoxal bis (2-hydroxyanil) (GBHA) staining or transmission electron microscopy combined with X-ray microanalysis. Transmission electron microscopy revealed Ca-phosphate deposits at the bottom of the resin-impregnated layer. The adhesive resin above the resin-impregnated layer was amorphous and showed no precipitates of Ca-phosphate. GBHA displayed intense calcium reactions throughout the resin-impregnated layer and also moderate ones in the 10 microns (Clearfil Liner Bond System) or 30 microns (IMPERVA Bonding System) thick boundary zone of the adhesive resin as well as in the resin tags. These data are the first to offer a distinct localization of calcium ions within the adhesive resin at the dentin-resin interface. PMID:9800373

  14. Covering of fiber-reinforced composite bars by adhesive materials, is it necessary to improve the bond strength of lingual retainers?

    PubMed Central

    Heravi, Farzin; Kerayechian, Navid; Moazzami, Saied Mostafa; Shafaee, Hooman; Heravi, Parya

    2015-01-01

    Objectives: The objectives were to evaluate the shear bond strength (SBS) of fiber-reinforced composite (FRC) retainers when bonding them to teeth with and without covering the FRC bars using two different adhesive systems. Materials and Methods: Hundred and twenty extracted human maxillary premolars were randomly divided into eight groups (n = 15). FRC bars (4 mm length, Everstick Ortho®, Stick Tech, Oy, Turku, Finland) were bonded to the proximal (distal) surfaces of the teeth using two different adhesives (Tetric Flow [TF, Ivoclar Vivadent, Switzerland] and resin-modified glass ionomer cement [RMGIC, ODP, Vista, CA, USA]) with and without covering with the same adhesive. Specimens were exposed to thermocycling (625 cycles per day [5–55°C, intervals: 30 s] for 8 days). The SBS test was then performed using the universal testing machine (Zwick, GMBH, Ulm, Germany). After debonding, the remaining adhesive on the teeth was recorded by the adhesive remnant index (0–3). Results: The lowest mean SBS (standard deviation) was found in the TF group without covering with adhesive (12.6 [2.11] MPa), and the highest bond strength was in the TF group with covering with adhesive (16.01 [1.09] MPa). Overall, the uncovered RMGIC (15.65 [3.57] MPa) provided a higher SBS compared to the uncovered TF. Covering of FRC with TF led to a significant increase in SBS (P = 0.001), but this was not true for RMGIC (P = 0.807). Thermal cycling did not significantly change the SBS values (P = 0.537). Overall, eight groups were statistically different (ANOVA test, F = 3.32, P = 0.034), but no significant differences in bond failure locations were found between the groups (Fisher's exact tests, P = 0.92). Conclusions: The present findings showed no significant differences between SBS of FRC bars with and without covering by RMGIC. However, when using TF, there was a significant difference in SBS measurements between covering and noncovering groups. Therefore, the use of RMGIC without

  15. Strength analysis and design of adhesive joints between circular elements made of metal and reinforced polymer materials

    NASA Astrophysics Data System (ADS)

    Pelekh, B. L.; Marchuk, M. V.; Kogut, I. S.

    1992-06-01

    The stress-strain state of an adhesive joint between cylindrical components made of a metal (steel) and a cross-reinforced filament-wound composite (glass/polymer or basalt/polymer) was investigated under static axial loading using newly proposed experimental techniques and a refined mathematical model. Analytical expressions are obtained for contact stresses in the adhesive joint. The maximum permissible load and the ultimate shear strength of the joint are determined. The experimental results are found to be in satisfactory agreement with model predictions.

  16. Marginal Sealing Durability of Two Contemporary Self-Etch Adhesives

    PubMed Central

    Khoroushi, Maryam; Mansoori, Mahsa

    2012-01-01

    Introduction. Sealing abilities of two self-etch adhesives were evaluated after two aging processes: storage in water and thermocycling. Materials and Methods. Cl V cavities were prepared on the buccal and lingual aspects of 48 human premolars, with cervical margins 1 mm below the CEJ. Clearfil Protect Bond (CPB) and BeautiBond (BB) (two-step and one-step self-etch adhesives, resp.) were applied, each to half of the cavities and restored with composite resin. Each group was randomly subdivided into 4 subgroups (n = 12) and evaluated for dye penetration after 24 hours, after 3000 thermocycling rounds, after a 6-month water storage, and after 3000 thermocycling rounds plus 6-month water storage, respectively. Data was analyzed using SPSS 11.5 and Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Results. There were no significant differences in enamel and dentin microleakage between the adhesives (P = 0.683; P = 0.154). Furthermore, no significant differences were observed in enamel microleakage of each one of CPB and BB (P = 0.061 and P = 0.318, resp.). However, significant decrease was observed in subgroups 3 and 4 (P = 0.001) for CPB dentinal margins. Conclusion. In this study, limited aging procedures had no influence on marginal integrity of composite resin restorations bonded with self-etch adhesives of CPB and BB. Furthermore, CPB dentinal sealing improved after aging. PMID:22611501

  17. Microtensile bond strength of silorane-based composite specific adhesive system using different bonding strategies

    PubMed Central

    Bastos, Laura Alves; Sousa, Ana Beatriz Silva; Drubi-Filho, Brahim; Panzeri Pires-de-Souza, Fernanda de Carvalho

    2015-01-01

    Objectives The aim of this study was to evaluate the effect of pre-etching on the bond strength of silorane-based composite specific adhesive system to dentin. Materials and Methods Thirty human molars were randomly divided into 5 groups according to the different bonding strategies. For teeth restored with silorane-based composite (Filtek Silorane, 3M ESPE), the specific self-etching adhesive system (Adhesive System P90, 3M ESPE) was used with and without pre-etching (Pre-etching/Silorane and Silorane groups). Teeth restored with methacrylate based-composite (Filtek Z250, 3M ESPE) were hybridized with the two-step self-etching system (Clearfil SE Bond, Kuraray), with and without pre-etching (Pre-etching/Methacrylate and Methacrylate groups), or three-step adhesive system (Adper Scotchbond Multi-Purpose, 3M ESPE) (Three-step/Methacrylate group) (n = 6). The restored teeth were sectioned into stick-shaped test specimens (1.0 × 1.0 mm), and coupled to a universal test machine (0.5 mm/min) to perform microtensile testing. Results Pre-etching/Methacrylate group presented the highest bond strength values, with significant difference from Silorane and Three-step/Methacrylate groups (p < 0.05). However, it was not significantly different from Preetching/Silorane and Methacrylate groups. Conclusions Pre-etching increased bond strength of silorane-based composite specific adhesive system to dentin. PMID:25671209

  18. Physics of Failure Analysis of Xilinx Flip Chip CCGA Packages: Effects of Mission Environments on Properties of LP2 Underfill and ATI Lid Adhesive Materials

    NASA Technical Reports Server (NTRS)

    Suh, Jong-ook

    2013-01-01

    The Xilinx Virtex 4QV and 5QV (V4 and V5) are next-generation field-programmable gate arrays (FPGAs) for space applications. However, there have been concerns within the space community regarding the non-hermeticity of V4/V5 packages; polymeric materials such as the underfill and lid adhesive will be directly exposed to the space environment. In this study, reliability concerns associated with the non-hermeticity of V4/V5 packages were investigated by studying properties and behavior of the underfill and the lid adhesvie materials used in V4/V5 packages.

  19. Proposed framework for cleanup and site restoration following a terrorist incident involving radioactive material.

    PubMed

    Conklin, W Craig

    2005-11-01

    Cleanup following a terrorism incident involving a radiological dispersal device (RDD) or improvised nuclear device (IND) is likely to be technically challenging, costly, and politically charged. Lessons learned from the Top Officials 2 exercise and the increased threat of terrorist use of an RDD or IND have driven federal officials to push for an agreed-upon process for determining appropriate cleanup levels. State and local authorities generally have the ultimate responsibility for final public health decisions in their jurisdictions. In response to terrorist attacks, local authorities are likely to request federal assistance in assessing the risk and establishing appropriate cleanup levels. It is realistic to expect local and state requests for significant federal assistance in planning and implementing recovery operations. State and local authorities may desire "shared accountability" with the federal government in setting the appropriate cleanup levels. Government officials at all levels will face pressure to say how clean is clean enough and how quickly people can re-enter affected areas. Issues arising include (1) the nature of the relationship between the federal, state, and local leadership involved in the recovery efforts and (2) where the funding for recovery comes from. Many agencies, including the U.S. Environmental Protection Agency (EPA), the U.S. Nuclear Regulatory Commission (NRC), and the U.S. Department of Energy (DOE) have long been involved in cleanup activities involving radioactive materials. These agencies have recognized the need for a participatory process and realize the need to remain flexible when faced with possible unprecedented environmental challenges following a terrorist attack. Currently, the Department of Homeland Security has a committee process underway, with participation of the EPA, NRC, DOE, and other federal agencies, to try to resolve these issues and to begin engaging state, local, and tribal governments, and others as

  20. Effect of Saliva on the Tensile Bond Strength of Different Generation Adhesive Systems: An In-Vitro Study

    PubMed Central

    Tripathi, Abhay Mani; Saha, Sonali; Dhinsa, Kavita; Garg, Aarti

    2015-01-01

    Background Newer development of bonding agents have gained a better understanding of factors affecting adhesion of interface between composite and dentin surface to improve longevity of restorations. Objective The present study evaluated the influence of salivary contamination on the tensile bond strength of different generation adhesive systems (two-step etch-and-rinse, two-step self-etch and one-step self-etch) during different bonding stages to dentin where isolation is not maintained. Materials and Methods Superficial dentin surfaces of 90 extracted human molars were randomly divided into three study Groups (Group A: Two-step etch-and-rinse adhesive system; Group B: Two-step self-etch adhesive system and Group C: One-step self-etch adhesive system) according to the different generation of adhesives used. According to treatment conditions in different bonding steps, each Group was further divided into three Subgroups containing ten teeth in each. After adhesive application, resin composite blocks were built on dentin and light cured subsequently. The teeth were then stored in water for 24 hours before sending for testing of tensile bond strength by Universal Testing Machine. The collected data were then statistically analysed using one-way ANOVA and Tukey HSD test. Results One-step self-etch adhesive system revealed maximum mean tensile bond strength followed in descending order by Two-step self-etch adhesive system and Two-step etch-and-rinse adhesive system both in uncontaminated and saliva contaminated conditions respectively. Conclusion Unlike One-step self-etch adhesive system, saliva contamination could reduce tensile bond strength of the two-step self-etch and two-step etch-and-rinse adhesive system. Furthermore, the step of bonding procedures and the type of adhesive seems to be effective on the bond strength of adhesives contaminated with saliva. PMID:26393214

  1. Adhesion behaviors on superhydrophobic surfaces.

    PubMed

    Zhu, Huan; Guo, Zhiguang; Liu, Weimin

    2014-04-18

    The adhesion behaviors of superhydrophobic surfaces have become an emerging topic to researchers in various fields as a vital step in the interactions between materials and organisms/materials. Controlling the chemical compositions and topological structures via various methods or technologies is essential to fabricate and modulate different adhesion properties, such as low-adhesion, high-adhesion and anisotropic adhesion on superhydrophobic surfaces. We summarize the recent developments in both natural superhydrophobic surfaces and artificial superhydrophobic surfaces with various adhesions and also pay attention to superhydrophobic surfaces switching between low- and high-adhesion. The methods to regulate or translate the adhesion of superhydrophobic surfaces can be considered from two perspectives. One is to control the chemical composition and change the surface geometric structure on the surfaces, respectively or simultaneously. The other is to provide external stimulations to induce transitions, which is the most common method for obtaining switchable adhesions. Additionally, adhesion behaviors on solid-solid interfaces, such as the behaviors of cells, bacteria, biomolecules and icing on superhydrophobic surfaces are also noticeable and controversial. This review is aimed at giving a brief and crucial overview of adhesion behaviors on superhydrophobic surfaces. PMID:24575424

  2. Viscoelastic Properties of Collagen-Adhesive Composites under Water Saturated and Dry Conditions

    PubMed Central

    Singh, Viraj; Misra, Anil; Parthasarathy, Ranganathan; Ye, Qiang; Spencer, Paulette

    2014-01-01

    To investigate the time and rate dependent mechanical properties of collagen-adhesive composites, creep and monotonic experiments are performed under dry and wet conditions. The composites are prepared by infiltration of dentin adhesive into a demineralized bovine dentin. Experimental results show that for small stress level under dry conditions, both the composite and neat adhesive have similar behavior. On the other hand, in wet conditions, the composites are significantly soft and weak compared to the neat adhesives. The behavior in the wet condition is found to be affected by the hydrophilicity of both the adhesive and collagen. Since the adhesive-collagen composites area part of the complex construct that forms the adhesive-dentin interface, their presence will affect the overall performance of the restoration. We find that Kelvin-Voigt model with at least 4-elements is required to fit the creep compliance data, indicating that the adhesive-collagen composites are complex polymers with several characteristics time-scales whose mechanical behavior will be significantly affected by loading rates and frequencies. Such mechanical properties have not been investigated widely for these types of materials. The derived model provides an additional advantage that it can be exploited to extract other viscoelastic properties which are, generally, time consuming to obtain experimentally. The calibrated model is utilized to obtain stress relaxation function, frequency-dependent storage and loss modulus, and rate dependent elastic modulus. PMID:24753362

  3. Machining accuracy of crowns by CAD/CAM system using TCP/IP: influence of restorative material and scanning condition.

    PubMed

    Tomita, Sachiko; Shin-ya, Akiyoshi; Gomi, Harunori; Shin-ya, Akikazu; Yokoyama, Daiichiro

    2007-07-01

    The purpose of this study was to determine the optimal condition for fabricating accurate crowns efficiently using an internet-based CAD/CAM system. The influences of three different CAD/CAM restorative materials (titanium, porcelain, and composite resin) and three different step-over scanning distances (0.01 mm, 0.11 mm, and 0.21 mm) were evaluated, and their interactive effects were carefully examined. Several points on the inner and outer surfaces of machined crowns - as well as height - were measured. These measurements were then compared with the original models, from which machining accuracy was obtained. At all measuring points, the inner surface of all crowns was machined larger than the die model, whereas the cervical area of porcelain crown was machined smaller than the crown model. Results of this study revealed that a step-over distance of 0.11 mm was an optimal scanning condition, taking into consideration the interactive effects of scanning time required, data volume, and machining accuracy. PMID:17886460

  4. Abdominal Adhesions

    MedlinePlus

    ... Adhesions 1 Ward BC, Panitch A. Abdominal adhesions: current and novel therapies. Journal of Surgical Research. 2011;165(1):91–111. Seek Help for ... and how to participate, visit the NIH Clinical Research Trials and You website ... Foundation for Functional Gastrointestinal Disorders 700 West Virginia ...

  5. Evaluation of the effect of water on three different light cured composite restorative materials stored in water: an in vitro study.

    PubMed

    Biradar, Basawaraj; Biradar, Sudharani; Ms, Arvind

    2012-01-01

    Objectives. The objective of this in vitro study was to investigate whether weight gain or loss in the three different composites occurs due to water absorption when they are stored in water. Methods. The composite restorative materials selected for this study included a microfine hybrid (Synergy) and two nanofilled composite restorative materials (Ceram X and Filtek Supreme Ultra). Twenty specimens of each material were fabricated of each composite material. Group A: Filtek Supreme Ultra, Group B: Synergy, Group C: Ceram X. Then all the specimens were stored in 10 ml Distilled water containing test tubes and placed in incubator at 37°C for six weeks. The weight changes of these specimens were measured daily for the first week and later once a week for next five weeks by using an electrical analytical balance. Results. The data was analyzed by one-way analysis of variance and Student's t test. All groups showed maximum amount of water absorption in the first week than gradual decrease in the water absorption from the second to the sixth week, as compared to the first week and there is no statistically significant difference between the groups tested. Conclusion. All the composite restorative material absorbs some amount of water. The water absorption of the composite may decrease the physical and mechanical properties of the composites; hence it is necessary to consider the type of the material before starting the treatment. PMID:22315607

  6. Practitioner, patient, and caries lesion characteristics associated with type of material used to restore carious teeth: findings from The Dental PBRN

    PubMed Central

    Makhija, Sonia K; Gordan, Valeria V.; Gilbert, Gregg H.; Litaker, Mark S.; Rindal, D. Brad; Pihlstrom, Daniel J.; Qvist, Vibeke

    2011-01-01

    Background The authors conducted a study to identify factors associated with material use by dentists in The Dental Practice-Based Research Network (DPBRN) when placing the first restoration on permanent tooth surfaces. Methods A total of 182 DPBRN practitioner-investigators provided data on 5,599 posterior teeth with caries. Practitioner-investigators completed an enrollment questionnaire that included the dentist’s age, gender, practice workload, practice type, and years since graduation. When a consented patient presented with a previously un-restored carious surface, practitioner-investigators recorded patient and tooth characteristics. Results Amalgam was used more often than direct resin-based composite (RBC) for posterior carious lesions. Practitioner/practice characteristics (years since graduation and type of practice); patient characteristics (gender, race, age, and dental insurance); and lesion characteristics (tooth location and surface, pre-and post-operative depth) were associated with the type of restorative material used. Conclusions There are several practitioner/practice, patient, and lesion characteristics significantly associated with use of amalgam and RBC: region, years since graduation, dental insurance, tooth location and surface, and pre-and post-operative depth. Clinical implications Amalgam remains a material commonly used by United States dentists to restore posterior caries lesions. PMID:21628683

  7. Bacterial leakage of mineral trioxide aggregate as compared with zinc-free amalgam, intermediate restorative material, and Super-EBA as a root-end filling material.

    PubMed

    Fischer, E J; Arens, D E; Miller, C H

    1998-03-01

    Several dye leakage studies have demonstrated the fact that mineral trioxide aggregate (MTA) leaks significantly less than other root-end filling materials. The purpose of this study was to determine the time needed for Serratia marcescens to penetrate a 3 mm thickness of zinc-free amalgam, Intermediate Restorative Material (IRM), Super-EBA, and MTA when these materials were used as root-end filling materials. Fifty-six, single-rooted extracted human teeth were cleaned and shaped with a series of .04 Taper rotary instruments (Pro-series 29 files). Once the canals were prepared in a crown down approach, the ends were resected and 48 root-end cavities were ultrasonically prepared to a 3 mm depth. The teeth were then steam sterilized. Using an aseptic technique, under a laminar air flow hood, the root-end cavities were filled with amalgam, IRM, Super-EBA, and MTA. Four root-end cavities were filled with thermoplasticized gutta-percha without a root canal sealer and served as positive controls. Another four root-end cavities were filled with sticky wax covered with two layers of nail polish and served as negative controls. The teeth were attached to presterilized (ethylene oxide gas) plastic caps, and the root ends were placed into 12-ml vials of phenol red broth. Using a micropipette, a tenth of a milliliter of S. marcescens was placed into the root canal of each tooth. To test the sterility of the apparatus set-up, the root canals of two teeth with test root-end filling materials and one tooth from the positive and negative control groups were filled with sterile saline. The number of days required for S. marcescens to penetrate the four root-end filling materials and grow in the phenol red broth was recorded and analyzed. Most of the samples filled with zinc-free amalgam leaked bacteria in 10 to 63 days. IRM began leaking 28 to 91 days. Super-EBA began leaking 42 to 101 days. MTA did not begin leaking until day 49. At the end of the study, four of the MTA samples

  8. Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials

    PubMed Central

    Sawani, Shefali; Arora, Vipin; Jaiswal, Shikha; Nikhil, Vineeta

    2014-01-01

    Background: Evaluation of microleakage is important for assessing the success of new restorative materials and methods. Aim and Objectives: Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials. Materials and Methods: Standardized mesi-occlusal (MO) and distoocclusal (DO) Class II tooth preparations were preparedon 53 molars and samples were randomly divided into six experimental groups and one control group for restorations. Group 1: Open-Sandwich technique (OST) with flowable composite at the gingival seat. Group 2: OST with resin-modified glass ionomer cement (RMGIC) at the gingival seat. Group 3: Closed-Sandwich technique (CST) with flowable composite at the pulpal floor and axial wall. Group 4: CST with RMGIC at the pulpal floor and axial wall. Group 5: OST with flowable composite at the pulpal floor, axial wall, and gingival seat. Group 6: OST with RMGIC at the pulpal floor, axial wall, and gingival seat. Group 7: Control — no lining material, centripetal technique only. After restorations and thermocycling, apices were sealed and samples were immersed in 0.5% basic fuchsin dye. Sectioning was followed by stereomicroscopic evaluation. Results: Results were analyzed using Post Hoc Bonferroni test (statistics is not a form of tabulation). Cervical scores of control were more than the exprimental groups (P < 0.05). Less microleakage was observed in CST than OST in all experimental groups (P < 0.05). However, insignificant differences were observed among occlusal scores of different groups (P > 0.05). Conclusion: Class II composite restorations with centripetal build-up alone or when placed with CST reduces the cervical microleakage when compared to OST. PMID:25125847

  9. Adhesive Cementation of Indirect Composite Inlays and Onlays: A Literature Review.

    PubMed

    D'Arcangelo, Camillo; Vanini, Lorenzo; Casinelli, Matteo; Frascaria, Massimo; De Angelis, Francesco; Vadini, Mirco; D'Amario, Maurizio

    2015-09-01

    The authors conducted a literature review focused on materials and techniques used in adhesive cementation for indirect composite resin restorations. It was based on English language sources and involved a search of online databases in Medline, EMBASE, Cochrane Library, Web of Science, Google Scholar, and Scopus using related topic keywords in different combinations; it was supplemented by a traditional search of peer-reviewed journals and cross-referenced with the articles accessed. The purpose of most research on adhesive systems has been to learn more about increased bond strength and simplified application methods. Adherent surface treatments before cementation are necessary to obtain high survival and success rates of indirect composite resin. Each step of the clinical and laboratory procedures can have an impact on longevity and the esthetic results of indirect restorations. Cementation seems to be the most critical step, and its long-term success relies on adherence to the clinical protocols. The authors concluded that in terms of survival rate and esthetic long-term outcomes, indirect composite resin techniques have proven to be clinically acceptable. However, the correct management of adhesive cementation protocols requires knowledge of adhesive principles and adherence to the clinical protocol in order to obtain durable bonding between tooth structure and restorative materials. PMID:26355440

  10. A proposal of microtomography evaluation for restoration interface gaps.

    PubMed

    Meleo, Deborah; Manzon, Licia; Pecci, Raffaella; Zuppante, Francesca; Bedini, Rossella

    2012-01-01

    Nowadays, several adhesive systems are used in dental restoration and they are evaluated by clinical research. In vitro evaluations are often made by means of traditional observation techniques (for example scanning electron microscope (SEM), while 3D cone-beam microtomography technique (3D micro-CT), that can be able to generate 3D sample images without any sample treatment during acquisition data, is going to be used a lot in the next few years. In dental cavity restored with composite, it is possible to predict the presence of gaps due to polymerization shrinkage; that is the reason this work purpose is to reveal by 3D images and measure by micro-CT analysis the voids generated applying the most used adhesive systems at the moment. By means of microtomographic analysis is proposed an aid to overcome bidimensional SEM investigation limits like random observation of sample surface, sample sectioning (to see inside it with the relative possible structural alterations induced on the same sample) and the gold sputtering treatment. For this experimental work, human crown teeth have been selected, all restored with the same composite material, using five adhesive systems. After about 48 hours each tooth has been acquired by means of Skyscan 1072 micro-CT instrument and then processed by 3D reconstruction and micro-CT analyser software. Three adhesive systems have showed 3D micro-CT images with not as much voids as expected, with a very little extent. This kind of micro-CT in vitro evaluation proposal suggests a method to observe and quantify the voids generated after polymerization shrinkage during tooth restoration. PMID:22456021

  11. Nanoleakage for Self-Adhesive Resin Cements used in Bonding CAD/CAD Ceramic Material to Dentin

    PubMed Central

    El-Badrawy, Wafa; Hafez, Randa Mohamed; El Naga, Abeer Ibrahim Abo; Ahmed, Doaa Ragai

    2011-01-01

    Objectives: To determine nanoleakage of CAD/CAM ceramic blocks bonded to dentin with self-adhesive resin cement. Methods: Eighteen sound extracted human molars were sterilized and sectioned into 3 mm-thick dentin sections. Trilux Cerec Vitablocks (Vita) were also sectioned into 3 mm sections, surface-treated using 5% hydrofluoric acid-etchant, and then coated with silane primer (Vita). Trilux and dentin sections were cemented together by means of three resin cements: Rely-X Unicem (3M/ESPE), BisCem (Bisco), and Calibra (Dentsply), according to manufacturers’ recommendations. Calibra was used in conjunction with Prime/Bond-NT adhesive (Dentsply), while the other two are self-adhesive. The bonded specimens were stored for 24h in distilled water at 37°C. Specimens were vertically sectioned into 1 mm-thick slabs, yielding up to six per specimen. Two central slabs were randomly chosen from each specimen making up the cement groups (n=12). Each group was subdivided into two subgroups (n=6), a control and a thermocycled subgroup (5–55°C) for 500 cycles. Slabs were coated with nail polish up to 1 mm from the interface, immersed in a 50% silver nitrate solution for 24h, and tested for nanoleakage using Quanta Environmental SEM and EDAX. Data were statistically analyzed using two-way ANOVA and Tukey’s post-hoc tests. Results: Rely-X Unicem and Calibra groups demonstrated no significant difference in the percentage of silver penetration, while the BisCem group revealed a significantly higher percentage (P≤.05). Thermocycling (500 cycles) did not have a statistically significant effect on the percentage of silver penetration (P>.05). Conclusions: One self-adhesive-resin cement demonstrated a similar sealing ability when compared with a standard resin cement. Thermo-cycling did not significantly increase dye penetration under the test conditions. PMID:21769269

  12. Control of cell adhesion on poly(methyl methacrylate).

    PubMed

    Patel, Shyam; Thakar, Rahul G; Wong, Josh; McLeod, Stephen D; Li, Song

    2006-05-01

    Keratoprostheses have been constructed from a wide variety of transparent materials, including poly(methyl methacrylate) (PMMA). However, the success of keratoprosthesis has been plagued by numerous shortcomings that include the weakening of the implant-host interface due to weak cell adhesion and opaque fibrous membrane formation over the inner surface of the implant due to fibroblast attachment. An effective solution requires a surface modification that would selectively allow enhanced cell attachment at the implant-host interface and reduced cell attachment over the interior surface of the implant. Here, we have developed a novel and simple peptide conjugation scheme to modify PMMA surfaces, which allowed for region-specific control of cell adhesion. This method uses di-amino-PEG, which can be grafted onto PMMA using hydrolysis or aminolysis method. PEG can resist cell adhesion and protein adsorption. The functionalization of grafted di-amino-PEG molecules with RGD peptide not only restored cell adhesion to the surfaces, but also enhanced cell attachment and spreading as compared to untreated PMMA surfaces. Long-term cell migration and micropatterning studies clearly indicated that PEG-PMMA surfaces with and without RGD conjugation can be used to differentiate cell adhesion and control cell attachment spatially on PMMA, which will have potential applications in the modification of keratoprostheses. PMID:16439014

  13. Casein Phosphopeptide-Amorphous Calcium Phosphate and Shear Bond Strength of Adhesives to Primary Teeth Enamel

    PubMed Central

    Farokh Gisovar, Elham; Hedayati, Nassim; Shadman, Niloofar; Shafiee, Leila

    2015-01-01

    Background: CPP-ACP (Phosphopeptide-Amorphous Calcium Phosphate) has an important role in caries prevention in pediatric patients. This study was done, because of the great use of CPP-ACP and the need for restoration for teeth treated with CPP-ACP as well as the importance of shear bond strength of adhesives in the success of restorations. Objectives: This study aimed to evaluate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on shear bond strength of dental adhesives to enamel of primary teeth molars. Materials and Methods: This in vitro study was conducted on 180 extracted primary molars. They were randomly divided into 6 groups and each group was divided into 2 subgroups (treated with CPP-ACP and untreated). In subgroups with CPP-ACP, enamel was treated with CPP-ACP paste 1 h/d for 5 days. Types of adhesives that were evaluated in this study were Tetric N-Bond, AdheSE, AdheSE One F, single Bond 2, SE Bond, and Adper Prompt L-Pop. Shear bond strength was tested with a universal testing machine and mode of failure was evaluated under stereomicroscope. Data were analyzed by T test, 2-way analysis of variance (ANOVA), Tukey and Fisher exact test using SPSS18. P < 0.05 was considered as significance level. Results: Shear bond strengths of different adhesive systems to enamel of primary teeth treated and untreated with CPP-ACP showed no significant difference (P > 0.05). Mode of failure in all groups regardless of CPP-ACP administration was mainly adhesive type. Our results indicated that CPP-ACP did not affect shear bond strength of studied adhesives to primary teeth enamel. Conclusions: To have a successful and durable composite restoration, having a high strength bonding is essential. Considering the wide use of CPP-ACP in preventing tooth decay and the role of adhesive shear bond strength (SBS) in success of composite restoration, we conducted the present study to evaluate the effect of CPP-ACP on the SBS of adhesives to primary teeth

  14. [The application of universal adhesives in dental bonding].

    PubMed

    Guo, Jingmei; Lei, Wenlong; Yang, Hongye; Huang, Cui

    2016-03-01

    The bonding restoration has become an important clinical technique for the development of dental bonding technology. Because of its easy operation and the maximum preservation of tooth tissues, bonding repair is widely used in dental restoration. The recent multi-mode universal adhesives have brought new progress in dental bonding restoration. In this article the universal adhesives were reviewed according to its definition, development, improvement, application features and possible problems. PMID:26980660

  15. Evaluation of the effect of tooth and dental restoration material on electron dose distribution and production of photon contamination in electron beam radiotherapy.

    PubMed

    Bahreyni Toossi, Mohammad Taghi; Ghorbani, Mahdi; Akbari, Fatemeh; Mehrpouyan, Mohammad; Sobhkhiz Sabet, Leila

    2016-03-01

    The aim of this study is to evaluate the effect of tooth and dental restoration materials on electron dose distribution and photon contamination production in electron beams of a medical linac. This evaluation was performed on 8, 12 and 14 MeV electron beams of a Siemens Primus linac. MCNPX Monte Carlo code was utilized and a 10 × 10 cm(2) applicator was simulated in the cases of tooth and combinations of tooth and Ceramco C3 ceramic veneer, tooth and Eclipse alloy and tooth and amalgam restoration materials in a soft tissue phantom. The relative electron and photon contamination doses were calculated for these materials. The presence of tooth and dental restoration material changed the electron dose distribution and photon contamination in phantom, depending on the type of the restoration material and electron beam's energy. The maximum relative electron dose was 1.07 in the presence of tooth including amalgam for 14 MeV electron beam. When 100.00 cGy was prescribed for the reference point, the maximum absolute electron dose was 105.10 cGy in the presence of amalgam for 12 MeV electron beam and the maximum absolute photon contamination dose was 376.67 μGy for tooth in 14 MeV electron beam. The change in electron dose distribution should be considered in treatment planning, when teeth are irradiated in electron beam radiotherapy. If treatment planning can be performed in such a way that the teeth are excluded from primary irradiation, the potential errors in dose delivery to the tumour and normal tissues can be avoided. PMID:26581762

  16. Evaluation of colour stability of provisional restorative materials exposed to different mouth rinses at varying time intervals: an in vitro study.

    PubMed

    Prasad, D Krishna; Alva, Harshitha; Shetty, Manoj

    2014-03-01

    The most important factor affecting esthetics is colour. Whether a definitive prosthesis or a provisional restoration, maintenance of esthetics is of prime concern along with restoration of function. Colour stability of provisional prosthesis is affected by various factors and various studies are documented in the literature on this. The purpose of this study was to evaluate the colour stability of provisional restorative materials exposed to different mouth rinses at varying time intervals. 120 discs, each of self cure tooth moulding material, Protemp 4 and Revotek LC were prepared and immersed in two mouth rinses, hexidine and periogard and evaluated for their colour stability after 1 week, 1 and 3 months. The data obtained was statistically analysed using ANOVA and Tukey's post hoc analysis. The results indicate that there is a significant difference in the colour variation of various materials in two different mouth rinses at different time intervals. Revotek LC was found to be the most colour stable material and periogard had the least staining potential at varying time intervals. PMID:24605003

  17. Shear bond strength of partial coverage restorations to dentin

    PubMed Central

    Agustín-Panadero, Rubén; Alonso-Pérez-Barquero, Jorge; Fons-Font, Antonio; Solá-Ruíz, María-Fernanda

    2015-01-01

    Background When partial coverage restorations (veneers, inlays, onlays…) must be cemented to dentin, bond strength may not reach the same predictable values as to enamel. The purpose of this study was: 1. To compare, with a shear bond test, the bond strength to dentin of a total-etch and a self-etching bonding agent. 2. To determine whether creating microretention improves the bond strength to dentin. Material and Methods Two bonding agents were assayed, Optibond FL® (Kerr), two-bottle adhesive requiring acid etching, and Clearfil SE Bond® (Kuraray), two-bottle self-etching adhesive. The vestibular, lingual, distal and mesial surfaces of ten molars (n=10) were ground to remove all enamel and 40 ceramic samples were cemented with Variolink II® (Ivoclar Vivadent). Half the molar surfaces were treated to create round microretention (pits) to determine whether these could influence bond strength to dentin. The 40 molar surfaces were divided into four groups (n=10): Optibond FL (O); Clearfil SE (C); Optibond FL + microretention (OM); Clearfil SE + micro retention (CM). A shear bond test was performed and the bond failures provoked examined under an optical microscope. Results O=35.27±8.02 MPa; C=36.23±11.23 MPa; OM=28.61±6.27 MPa; CM=27.01±7.57 MPa. No statistically significant differences were found between the adhesives. Optibond FL showed less statistical dispersion than Clearfil SE. The presence of microretentions reduced bond strength values regardless of the adhesive used. Conclusions 1. Clearfil SE self-etching adhesive and Optibond FL acid-etch showed adequate bond strengths and can be recommended for bonding ceramic restorations to dentin. 2. The creation of round microretention pits compromises these adhesives’ bond strength to dentin. Key words:Adhesion to dentin, bonding agent, Optibond FL, Clearfil SE, microretention, shear bond test. PMID:26330937

  18. Evaluation of Surlyn 8920 as PHE Visor Material and Evaluations of New Adhesives for Improving Bonding Between Teflon and Stainless Steel at Cryogenic Temperature

    NASA Technical Reports Server (NTRS)

    Ray, Asit K.

    1991-01-01

    Two studies are presented, and in the first study, Surlyn 8920 (an ionic and amorphous low density polyethylene made by Dupont) was evaluated as a possible replacement of Plexyglass G as PHE visor material. Four formulations of the polymer were made by adding different amounts of UV stabilizer, energy quencher, and antioxident in a Brabender Plasticorder. The formulated polymers were molded in the form of sheets in a compression molder. Cut samples from the molded sheets were exposed in a weatherometer and tested on Instron Tensile Tester for strength and elongation. Specially molded samples of the formulated polymers were subjected to Charpy Impact Tests. In the second study, preliminary evaluations of adhesives for improvement of bonding between Teflon and stainless steel (SS) were performed. Kapton, a high temperature polyimide made by Dupont, and a rubber based adhesive made by Potter Paint Co., were evaluated against industrial quality epoxy, the current material used to bond Teflon and SS. The degreased surfaces of the SS discs were etched mechanically, with a few of these etched chemically. The surfaces of the SS discs were etched mechanically, with a few of these etched chemically. Bonding strengths were evaluated using lap shear tests on the Instron Tensile Tester for the samples bonded by Kapton and industrial quality epoxy. Bond strengths were also evaluated using a pull test on the Instron for the samples bonded by Potter adhesive (CWL-152) and industrial quality epoxy. Based on limited lap shear data, Kapton gave bond strength favorable compared to that of industrial epoxy. Based on limited pull test data, Kapton bonded and CWL-152 bonded samples showed poor strength compared to epoxy bonded sample.

  19. Measuring Adhesion And Friction Forces

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1991-01-01

    Cavendish balance adapted to new purpose. Apparatus developed which measures forces of adhesion and friction between specimens of solid materials in vacuum at temperatures from ambient to 900 degrees C. Intended primarily for use in studying adhesion properties of ceramics and metals, including silicon carbide, aluminum oxide, and iron-base amorphous alloys.

  20. Cementation of Glass-Ceramic Posterior Restorations: A Systematic Review

    PubMed Central

    van den Breemer, Carline R. G.; Gresnigt, Marco M. M.; Cune, Marco S.

    2015-01-01

    Aim. The aim of this comprehensive review is to systematically organize the current knowledge regarding the cementation of glass-ceramic materials and restorations, with an additional focus on the benefits of Immediate Dentin Sealing (IDS). Materials and Methods. An extensive literature search concerning the cementation of single-unit glass-ceramic posterior restorations was conducted in the databases of MEDLINE (Pubmed), CENTRAL (Cochrane Central Register of Controlled Trials), and EMBASE. To be considered for inclusion, in vitro and in vivo studies should compare different cementation regimes involving a “glass-ceramic/cement/human tooth” complex. Results and Conclusions. 88 studies were included in total. The in vitro data were organized according to the following topics: (micro)shear and (micro)tensile bond strength, fracture strength, and marginal gap and integrity. For in vivo studies survival and quality of survival were considered. In vitro studies showed that adhesive systems (3-step, etch-and-rinse) result in the best (micro)shear bond strength values compared to self-adhesive and self-etch systems when luting glass-ceramic substrates to human dentin. The highest fracture strength is obtained with adhesive cements in particular. No marked clinical preference for one specific procedure could be demonstrated on the basis of the reviewed literature. The possible merits of IDS are most convincingly illustrated by the favorable microtensile bond strengths. No clinical studies regarding IDS were found. PMID:26557651

  1. Comparative radiopacity of six current adhesive systems

    PubMed Central

    de Moraes Porto, Isabel Cristina Celerino; Honório, Naira Cândido; Amorim, Dayse Annie Nicácio; de Melo Franco, Áurea Valéria; Penteado, Luiz Alexandre Moura; Parolia, Abhishek

    2014-01-01

    Background: The radiopacity of contemporary adhesive systems has been mentioned as the indication for replacement of restorations due to misinterpretation of radiographic images. Aims: This study aimed to evaluate the radiopacity of contemporary bonding agents and to compare their radiodensities with those of enamel and dentin. Methods and Materials: To measure the radiopacity, eight specimens were fabricated from Clearfil SE Bond (CF), Xeno V (XE), Adper SE Bond (ASE), Magic Bond (MB), Single Bond 2 (SB), Scotchbond Multipurpose (SM), and gutta-percha (positive control). The optical densities of enamel, dentin, the bonding agents, gutta-percha, and an aluminium (Al) step wedge were obtained from radiographic images using image analysis software. Statistical Analysis: The radiographic density data were analyzed statistically by analysis of variance and Tukey's test (α =0.05). Results: Significant differences were found between ASE and all other groups tested and between XE and CF. No statistical difference was observed between the radiodensity of 1 mm of Al and 1 mm of dentin, between 2 mm of Al and enamel, and between 5 mm of Al and gutta-percha. Five of the six adhesive resins had radiopacity values that fell below the value for dentin, whereas the radiopacity of ASE adhesive was greater than that of dentin but below that of enamel. Conclusion: This investigation demonstrates that only ASE presented a radiopacity within the values of dentin and enamel. CF, XE, MB, SB, and SM adhesives are all radiolucent and require alterations to their composition to facilitate their detection by means of radiographic images. PMID:24554865

  2. Optimizing Adhesive Design by Understanding Compliance.

    PubMed

    King, Daniel R; Crosby, Alfred J

    2015-12-23

    Adhesives have long been designed around a trade-off between adhesive strength and releasability. Geckos are of interest because they are the largest organisms which are able to climb utilizing adhesive toepads, yet can controllably release from surfaces and perform this action over and over again. Attempting to replicate the hierarchical, nanoscopic features which cover their toepads has been the primary focus of the adhesives field until recently. A new approach based on a scaling relation which states that reversible adhesive force capacity scales with (A/C)(1/2), where A is the area of contact and C is the compliance of the adhesive, has enabled the creation of high strength, reversible adhesives without requiring high aspect ratio, fibrillar features. Here we introduce an equation to calculate the compliance of adhesives, and utilize this equation to predict the shear adhesive force capacity of the adhesive based on the material components and geometric properties. Using this equation, we have investigated important geometric parameters which control force capacity and have shown that by controlling adhesive shape, adhesive force capacity can be increased by over 50% without varying pad size. Furthermore, we have demonstrated that compliance of the adhesive far from the interface still influences shear adhesive force capacity. Utilizing this equation will allow for the production of adhesives which are optimized for specific applications in commercial and industrial settings. PMID:26618537

  3. Making human enamel and dentin surfaces superwetting for enhanced adhesion

    NASA Astrophysics Data System (ADS)

    Vorobyev, A. Y.; Guo, Chunlei

    2011-11-01

    Good wettability of enamel and dentin surfaces is an important factor in enhancing adhesion of restorative materials in dentistry. In this study, we developed a femtosecond laser surface texturing approach that makes both the enamel and dentine surfaces superwetting. In contrast to the traditional chemical etching that yields random surface structures, this approach produces engineered surface structures. The surface structure engineered and tested here is an array of parallel microgrooves that generates a strong capillary force. Due to the powerful capillary action, water is rapidly sucked into this engineered surface structure and spreads even on a vertical surface.

  4. The merits of artificial selection for the development of restoration-ready plant materials of native perennial grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While seed harvested from remnant stands of grass can be used for restoration in temperate regions, seed recovery in semi-arid and arid environments is often unreliable and of low yield and quality. In addition, ongoing harvest of indigenous populations can be unsustainable, especially for those th...

  5. Research study on materials processing in space experiment number M512. [adhesion-cohesion phenomena under weightlessness

    NASA Technical Reports Server (NTRS)

    Tobin, J. M.

    1974-01-01

    Conclusions of the team of specialists can be generalized as: (1) Brazing and welding of metal structures in an orbital near zero gravity condition are quite feasible. (2) Design of joints for fabrication in zero gravity will place less emphasis on the tolerances and proximity of the adjacent structures than on the quantity of liquid metal available. (3) Brazing of metallic joints has many advantages over electron beam welding for practical reasons: simplicity, launch weight, development costs, joint design tolerances, remotization, etc. (4) No evidence of different physical or mechanical properties of liquid metals in zero gravity was observed. However, many differences in liquid behavior were observed. Many of these effects have been called adhesion-cohesion phenomena.

  6. Polyimide adhesives

    NASA Technical Reports Server (NTRS)

    Progar, D. J.; Bell, V. L.; Saintclair, T. L. (Inventor)

    1974-01-01

    A process of preparing aromatic polyamide-acids for use as adhesives is described. An equimolar quantity of an aromatic dianhydride is added to a stirred solution of an aromatic diamine in a water or alcohol-miscible ether solvent to obtain a viscous polymer solution. The polymeric-acid intermediate polymer does not become insoluble but directly forms a smooth viscous polymer solution. These polyamic-acid polymers are converted, by heating in the range of 200-300 C and with pressure, to form polyimides with excellent adhesive properties.

  7. Influence of surface treatment of contaminated lithium disilicate and leucite glass ceramics on surface free energy and bond strength of universal adhesives.

    PubMed

    Yoshida, Fumi; Tsujimoto, Akimasa; Ishii, Ryo; Nojiri, Kie; Takamizawa, Toshiki; Miyazaki, Masashi; Latta, Mark A

    2015-01-01

    This study investigates the influence of surface treatment of contaminated lithium disilicate and leucite glass ceramic restorations on the bonding efficacy of universal adhesives. Lithium disilicate and leucite glass ceramics were contaminated with saliva, and then cleaned using distilled water (SC), or 37% phosphoric acid (TE), or hydrofluoric acid (CE). Specimens without contamination served as controls. The surface free energy was determined by measuring the contact angles formed when the three test liquids were placed on the specimens. Bond strengths of the universal adhesives were also measured. Saliva contamination and surface treatment of ceramic surfaces significantly influenced the surface free energy. The bond strengths of universal adhesives were also affected by surface treatment and the choice of adhesive materials. Our data suggest that saliva contamination of lithum disilicate and leucite glass ceramics significantly impaired the bonding of the universal adhesives, and reduced the surface free energy of the ceramics. PMID:26632235

  8. Structural and in vitro adhesion analysis of a novel covalently coupled bioactive composite.

    PubMed

    Khan, Abdul S; Hassan, Khawaja R; Bukhari, Syeda F; Wong, Ferranti S L; Rehman, Ihtesham U

    2012-01-01

    The interfacial adhesion between a restorative composite and tooth is one of the major factors that determine the ultimate performance of composite restoration. A novel polyurethane (PU) composite material was prepared by chemically binding the nano-hydroxyapatite (nHA) to the diisocyanate component in the PU backbone by utilizing solvent polymerization. The procedure involved stepwise addition of monomeric units of the PU and optimizing the reagent concentrations. The resultant materials were characterized structurally (Raman Spectroscopy) and in vitro bioactive analysis was conducted in modified-simulated body fluid for periodical time intervals. The in vitro study evaluated the push-out bond strength of existing obturating material and novel covalently linked PU/nHA composites to dentin after long-term storage in deionized water and artificial saliva. Human extracted molar roots were filled with experimental samples and analyzed at predetermined time intervals. The shear bond strength of samples was measured and surface morphologies were evaluated. Covalent bond formation was achieved between PU and nHA without intermediate coupling agent. With the increase in concentration of nHA, the composite showed more bioactivity and adhesion toward tooth structure. Bond strength of this new composite were in accordance with obutrating material, therefore, the material can be used as an obturating material because of its direct adhesion with tooth structure. PMID:22102537

  9. Protein mediated membrane adhesion

    NASA Astrophysics Data System (ADS)

    Carlson, Andreas; Mahadevan, L.

    2015-05-01

    Adhesion in the context of mechanical attachment, signaling, and movement in cellular dynamics is mediated by the kinetic interactions between membrane-embedded proteins in an aqueous environment. Here, we present a minimal theoretical framework for the dynamics of membrane adhesion that accounts for the kinetics of protein binding, the elastic deformation of the membrane, and the hydrodynamics of squeeze flow in the membrane gap. We analyze the resulting equations using scaling estimates to characterize the spatiotemporal features of the adhesive patterning and corroborate them using numerical simulations. In addition to characterizing aspects of cellular dynamics, our results might also be applicable to a range of phenomena in physical chemistry and materials science where flow, deformation, and kinetics are coupled to each other in slender geometries.

  10. Flexibilized copolyimide adhesives

    NASA Technical Reports Server (NTRS)

    Progar, Donald J.; St.clair, Terry L.

    1988-01-01

    Two copolyimides, LARC-STPI and STPI-LARC-2, with flexible backbones were processed and characterized as adhesives. The processability and adhesive properties were compared to those of a commercially available form of LARC-TPI. Lap shear specimens were fabricated using adhesive tape prepared from each of the three polymers. Lap shear tests were performed at room temperature, 177 C, and 204 C before and after exposure to water-boil and to thermal aging at 204 C for up to 1000 hours. The three adhesive systems possess exceptional lap shear strengths at room temperature and elevated temperatures both before and after thermal exposure. LARC-STPI, because of its high glass transition temperature provided high lap shear strengths up to 260 C. After water-boil, LARC-TPI exhibited the highest lap shear strengths at room temperature and 177 C, whereas the LARC-STPI retained a higher percentage of its original strength when tested at 204 C. These flexible thermoplastic copolyimides show considerable potential as adhesives based on this study and because of the ease of preparation with low cost, commercially available materials.

  11. Clinical Investigation of a New Bulk Fill Composite Resin in the Restoration of Posterior Teeth

    ClinicalTrials.gov

    2016-09-07

    Dental Restoration Failure of Marginal Integrity; Dental Caries; Unrepairable Overhanging of Dental Restorative Materials; Poor Aesthetics of Existing Restoration; Secondary Dental Caries Associated With Failed or Defective Dental Restorations; Fractured Dental Restorative Materials Without Loss of Materials; Fracture of Dental Restorative Materials With Loss of Material

  12. In vitro performance of Class I and II composite restorations: a literature review on nondestructive laboratory trials--part I.

    PubMed

    Dietschi, D; Argente, A; Krejci, I; Mandikos, M

    2013-01-01

    Posterior adhesive restorations are a basic procedure in general dental practices, but their application remains poorly standardized as a result of the number of available options. An abundant number of study hypotheses corresponding to almost unlimited combinations of preparation techniques, adhesive procedures, restorative options, and materials have been described in the literature and submitted to various evaluation protocols. A literature review was thus conducted on adhesive Class I and II restorations and nondestructive in vitro tests using the PubMed/Medline database for the 1995-2010 period. The first part of this review discusses the selected literature related to photoelasticity, finite element analysis (FEM), and microleakage protocols. Based on the aforementioned evaluation methods, the following parameters proved influential: cavity dimensions and design, activation mode (light or chemical), type of curing light, layering technique, and composite structure or physical characteristics. Photoelasticity has various limitations and has been largely (and advantageously) replaced by the FEM technique. The results of microleakage studies proved to be highly inconsistent, and the further use of this technique should be strictly limited. Other study protocols for adhesive Class II restorations were also reviewed and will be addressed in part II of this article, together with a tentative relevance hierarchy of selected in vitro methods. PMID:23738673

  13. Complex layered dental restorations: Are they recognizable and do they survive extreme conditions?

    PubMed

    Soon, Alistair S; Bush, Mary A; Bush, Peter J

    2015-09-01

    Recent research has shown that restorative dental materials can be recognized by microscopy and elemental analysis (scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray fluorescence; SEM/EDS and XRF) and that this is possible even in extreme conditions, such as cremation. These analytical methods and databases of dental materials properties have proven useful in DVI (disaster victim identification) of a commercial plane crash in 2009, and in a number of other victim identification cases. Dental materials appear on the market with ever expanding frequency. With their advent, newer methods of restoration have been proposed and adopted in the dental office. Methods might include placing multiple layers of dental materials, where they have different properties including adhesion, viscosity, or working time. These different dental materials include filled adhesives, flowable resins, glass ionomer cements, composite resins, liners and sealants. With possible combinations of different materials in these restorations, the forensic odontologist is now confronted with a new difficulty; how to recognize each individual material. The question might be posed if it is even possible to perform this task. Furthermore, an odontologist might be called upon to identify a victim under difficult circumstances, such as when presented with fragmented or incinerated remains. In these circumstances the ability to identify specific dental materials could assist in the identification of the deceased. Key to use of this information is whether these new materials and methods are detailed in the dental chart. Visual or radiographic inspection may not reveal the presence of a restoration, let alone the possible complex nature of that restoration. This study demonstrates another scientific method in forensic dental identification. PMID:26151675

  14. Evaluation of cuspal deflection in premolar teeth restored with low shrinkable resin composite (in vitro study)

    PubMed Central

    Labib, Labib Mohamed; Nabih, Sameh Mahmoud; Baroudi, Kusai

    2015-01-01

    Objectives: This study evaluated cuspal deflection in premolar teeth restored with low shrinkable resin composite. Materials and Methods: A total of 40 human premolars were used for cuspal deflection evaluation in this study. Each group was divided into four equal groups according to the type of resin composite and the adhesive used as follows: group A: Using low shrinkable resin composite (silorane) with its adhesive system; group B: Using low shrinkable composite (silorane) with G-bond; group C: Using Filtek Z350 composite with G-bond; and group D: Using Filtek Z350 composite with AdheSE. Cusp deflection was detected using Universal measuring microscope and laser horizontal metroscope. Results: This study was done to investigate the effect of polymerization shrinkage stresses of two resin composite materials (Filtek Z350 and Filtek P90) on cuspal deflection of mesio-occluso-distal restoration. For this study, the extracted non-carious maxillary second premolars were selected. Forty teeth that showed no more than 5% variation in their dimensions were used. A significant increase in cuspal deflection of cavities restored with the methacrylate-based (Filtek Z350) compared with the silorane (P90) resin-based composites was obtained. Conclusion: The change in the organic matrix or materials formulation of the resin composite using silorane has a positive effect on controlling the cusp deflection. PMID:26759800

  15. Influence of coronal restorations on the fracture resistance of root canal-treated premolar and molar teeth: a retrospective study.

    PubMed

    Dammaschke, Till; Nykiel, Kathrin; Sagheri, Darius; Schäfer, Edgar

    2013-08-01

    To evaluate the influence of coronal restorations on the fracture resistance of endodontically treated teeth, 676 root canal-filled and restored posterior teeth were evaluated after a mean period of 9.7 (± 2.8; minimum: 5) years. A total of 86.2% of the endodontically treated and restored teeth survived the mean observation period of 9.7 years without fracture. The overall survival period was 13.6 (± 0.2) years. All teeth with gold partial crowns survived without fractures (n = 24). Teeth with crowns and adhesively sealed access cavities showed a mean survival period of 15.3 (± 0.4) years, with crown and bridge restorations 14.0 (± 0.3), with individual metal posts 13.9 (± 0.2), with composite fillings 13.4 (± 0.5), with prefabricated metal posts 12.7 (± 0.6), with amalgam fillings 11.8 (± 0.6) and with glass ionomer cements (GIC) 6.6 (± 0.5) years. Teeth with one or two surfaces restored by amalgam, composite or GIC showed a significantly lower fracture rate than teeth with three and more restored surfaces (P < 0.05). The mean fracture rate of teeth restored with GIC was significantly higher when compared with all other groups (P < 0.001). In general, endodontically treated teeth restored with prosthetic restorations demonstrated a significantly lower mean fracture rate than teeth restored with fillings. Cavities with up to three surfaces may well be successfully restored adhesively with composite filling material. PMID:23890259

  16. Simultaneous formation of fine and large-area electrode patterns using screen-offset printing and its application to the patterning on adhesive materials

    NASA Astrophysics Data System (ADS)

    Nomura, Ken-ichi; Ushijima, Hirobumi; Nagase, Kazuro; Ikedo, Hiroaki; Mitsui, Ryosuke; Sato, Junya; Takahashi, Seiya; Nakajima, Shin-ichiro; Arai, Masahiro; Kurata, Yuji; Iwata, Shiro

    2016-03-01

    Additive-type printing techniques such as gravure-offset printing and screen printing are effective for low-cost and ecofriendly electrode pattern formation. Gravure-offset printing is effective for fine pattern formation with widths on the order of 10-20 µm, whereas screen printing is effective for the formation of large-area patterns. However, it is difficult to simultaneously form fine and large-area patterns using these printing techniques. In this study, we demonstrate that fine (minimum width of 15 µm) and medium- as well as large-area patterns can be formed simultaneously using our developed screen-offset printing technique, which is a combination of screen printing on a silicone blanket and transfer printing from the blanket to a substrate. Furthermore, we demonstrate the application of our method to printing on adhesive materials, which allows electrode formation without applying heat to the film substrate.

  17. Wood Composite Adhesives

    NASA Astrophysics Data System (ADS)

    Gomez-Bueso, Jose; Haupt, Robert

    The global environment, in which phenolic resins are being used for wood composite manufacture, has changed significantly during the last decade. This chapter reviews trends that are driving the use and consumption of phenolic resins around the world. The review begins with recent data on volume usage and regional trends, followed by an analysis of factors affecting global markets. In a section on environmental factors, the impact of recent formaldehyde emission regulations is discussed. The section on economics introduces wood composite production as it relates to the available adhesive systems, with special emphasis on the technical requirement to improve phenolic reactivity. Advances in composite process technology are introduced, especially in regard to the increased demands the improvements place upon adhesive system performance. The specific requirements for the various wood composite families are considered in the context of adhesive performance needs. The results of research into current chemistries are discussed, with a review of recent findings regarding the mechanisms of phenolic condensation and acceleration. Also, the work regarding alternate natural materials, such as carbohydrates, lignins, tannins, and proteinaceous materials, is presented. Finally, new developments in alternative adhesive technologies are reported.

  18. Restoring primary anterior teeth.

    PubMed

    Waggoner, William F

    2002-01-01

    A variety of esthetic restorative materials are available for restoring primary incisors. Knowledge of the specific strengths, weakness, and properties of each material will enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Each has distinct advantages and disadvantages and the clinical conditions of placement may be a strong determining factor as to which material is utilized. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and those crowns that are luted onto the tooth and are some type of stainless steel crown. However, due to lack of supporting clinical data, none of the crowns can be said to be superior to the others under all circumstances. Though caries in the mandibular region is rare, restorative solutions for mandibular incisors are needed. Neither stainless steel crowns nor celluloid crown forms are made specifically for mandibular incisors. Many options exist to repair carious primary incisors, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success. Operator preferences, esthetic demands by parents, the child's behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen. PMID:12412967

  19. Cariogenic bacteria degrade dental resin composites and adhesives.

    PubMed

    Bourbia, M; Ma, D; Cvitkovitch, D G; Santerre, J P; Finer, Y

    2013-11-01

    A major reason for dental resin composite restoration replacement is related to secondary caries promoted by acid production from bacteria including Streptococcus mutans (S. mutans). We hypothesized that S. mutans has esterase activities that degrade dental resin composites and adhesives. Standardized specimens of resin composite (Z250), total-etch (Scotchbond Multipurpose, SB), and self-etch (Easybond, EB) adhesives were incubated with S. mutans UA159 or uninoculated culture medium (control) for up to 30 days. Quantification of the BisGMA-derived biodegradation by-product, bishydroxy-propoxy-phenyl-propane (BisHPPP), was performed by high-performance liquid chromatography. Surface analysis of the specimens was performed by scanning electron microscopy (SEM). S. mutans was shown to have esterase activities in levels comparable with those found in human saliva. A trend of increasing BisHPPP release throughout the incubation period was observed for all materials and was more elevated in the presence of bacteria vs. control medium for EB and Z250, but not for SB (p < .05). SEM confirmed the increased degradation of all materials with S. mutans UA159 vs. control. S. mutans has esterase activities at levels that degrade resin composites and adhesives; degree of degradation was dependent on the material's chemical formulation. This finding suggests that the resin-dentin interface could be compromised by oral bacteria that contribute to the progression of secondary caries. PMID:24026951

  20. Current status of zirconia restoration.

    PubMed

    Miyazaki, Takashi; Nakamura, Takashi; Matsumura, Hideo; Ban, Seiji; Kobayashi, Taira

    2013-10-01

    currently one of the most reliable bonding systems for zirconia. Adhesive treatments could be applied to luting the restorations and fabricating hybrid-structured FDPs. Full-contour zirconia FDPs caused concern about the wear of antagonist enamel, because the hardness of Y-TZP was over double that of porcelain. However, this review demonstrates that highly polished zirconia yielded lower antagonist wear compared with porcelains. Polishing of zirconia is possible, but glazing is not recommended for the surface finish of zirconia. Clinical data since 2010 are included in this review. The zirconia frameworks rarely got damaged in many cases and complications often occurred in the veneering ceramic materials. Further clinical studies with larger sample sizes and longer follow-up periods are required to investigate the possible influencing factors of technical failures. PMID:24140561

  1. Pulpal inflammatory responses following non-carious class V restorations.

    PubMed

    About, I; Murray, P E; Franquin, J C; Remusat, M; Smith, A J

    2001-01-01

    The effects of inflammatory activity following surgical intervention can injure pulp tissues; in severe cases it can lead to pulpal complications. With this article, the authors report on the effects of cavity preparation and restoration events and how they can interact together to reduce or increase the severity of pulpal inflammatory activity in 202 restored Class V cavities. Although some inflammatory activity was observed in the absence of bacteria, the severity of pulpal inflammatory activity was increased when cavity restorations became infected. Zinc oxide eugenol and resin-modified glass ionomer cement prevented bacterial microleakage in cavity restorations, with no severe inflammatory activity observed with these materials. Bacteria were observed in cavities restored with enamel bonding resin and adhesive bonded composites and were associated with severe grades of inflammatory activity. The cavity remaining dentin thickness influenced the grade of inflammatory activity. In the absence of infection, the grade of inflammatory activity decreased after 20 weeks post-operatively. In the presence of infection, the grade of pulpal inflammation remained stable until a minimum of 30 weeks had elapsed. PMID:11504432

  2. Comparative evaluation of surface properties of enamel and different esthetic restorative materials under erosive and abrasive challenges: An in vitro study

    PubMed Central

    Kaur, Simranjeet; Makkar, Sameer; Kumar, Rajneesh; Pasricha, Shinam; Gupta, Pranav

    2015-01-01

    Introduction: Noncarious tooth surface loss is a normal physiological process occurring throughout the life, but it can often become a problem affecting function, esthetics or cause pain. Aim: The purpose of this study was to assess the effect of erosive and abrasive challenges on the surface microhardness and surface wear of enamel and three different restorative materials, that is, nanofilled composite, microfilled composite and resin-modified glass ionomer cement (RMGIC) by using Vickers microhardness tester and profilometer respectively. Subjects and Methods: Nanofilled composite (Filtek™ Z350 × T), microfilled composite (Heliomolar®) and RMGIC (Fuji II LC) were used in the study. Results: Nanofilled composite resin has the best resistance to erosion and/or abrasion among all the materials tested, followed by microfilled composite and RMGIC respectively. Conclusion: Toothbrush abrasion has a synergistic effect with erosion on substance loss of human enamel, composites, and RMGIC. The susceptibility to acid and/or toothbrush abrasion of human enamel was higher compared to restorative materials. PMID:26752876

  3. Phoneme Restoration.

    ERIC Educational Resources Information Center

    Samuel, Arthur

    1996-01-01

    Notes that phonemic restoration is a powerful auditory illusion. Points out that when part of an utterance is replaced by another sound, listeners perceptually restore the missing speech. Several paradigms measure this illusion and explore its bottom-up and top-down bases. Findings reveal that acoustic properties of the replacement sound strongly…

  4. Tunicate-mimetic nanofibrous hydrogel adhesive with improved wet adhesion.

    PubMed

    Oh, Dongyeop X; Kim, Sangsik; Lee, Dohoon; Hwang, Dong Soo

    2015-07-01

    The main impediment to medical application of biomaterial-based adhesives is their poor wet adhesion strength due to hydration-induced softening and dissolution. To solve this problem, we mimicked the wound healing process found in tunicates, which use a nanofiber structure and pyrogallol group to heal any damage on its tunic under sea water. We fabricated a tunicate-mimetic hydrogel adhesive based on a chitin nanofiber/gallic acid (a pyrogallol acid) composite. The pyrogallol group-mediated cross-linking and the nanofibrous structures improved the dissolution resistance and cohesion strength of the hydrogel compared to the amorphous polymeric hydrogels in wet condition. The tunicate-mimetic adhesives showed higher adhesion strength between fully hydrated skin tissues than did fibrin glue and mussel-mimetic adhesives. The tunicate mimetic hydrogels were produced at low cost from recyclable and abundant raw materials. This tunicate-mimetic adhesive system is an example of how natural materials can be engineered for biomedical applications. PMID:25841348

  5. Effect of restoration size on fracture resistance of bonded amalgam restorations.

    PubMed

    Lindemuth, J S; Hagge, M S; Broome, J S

    2000-01-01

    The purpose of this study was to determine the effect of restoration size on the fracture strength of amalgam restorations bonded with Amalgambond Plus (with HPA). Research has shown that this adhesive is dispersed throughout the unset amalgam during condensation and that a decrease in diametral tensile strength, proportional to the amount of adhesive incorporated into the unset amalgam, has resulted. Smaller cavity preparations have a higher ratio of surface area to volume than do larger preparations, and it was anticipated that a proportionately greater amount of adhesive would be incorporated into smaller amalgam restorations. Sixty extracted human molars were divided into four groups of 15 teeth and mounted in tray acrylic-filled PVC cylinders. Shallow approximo-occlusal channels were prepared in two groups. One group was restored with Amalgambond Plus and Tytin amalgam, the other with just Tytin amalgam. Larger proximo-occlusal preparations were made in the remaining two groups, then restored in the same fashion. Samples were stored in 37 degrees C for at least 24 hours, then thermocycled from 5-55 degrees C 1000 times with a one-minute dwell time. Specimens were mounted in a Universal Testing Machine, and a chisel was applied to the restorations in compression mode at a crosshead speed of 5.0 mm/minute until bulk fracture of the amalgam occurred. The results indicated no difference in bulk fracture strengths between large amalgam restorations restored with and without Amalgambond Plus. However, small amalgam restorations restored with Amalgambond Plus exhibited significantly greater (p < 0.025) bulk fracture strengths than small amalgam restorations restored without use of the adhesive. PMID:11203813

  6. Photoresist substrate having robust adhesion

    DOEpatents

    Dentinger, Paul M.

    2005-07-26

    A substrate material for LIGA applications w hose general composition is Ti/Cu/Ti/SiO.sub.2. The SiO.sub.2 is preferably applied to the Ti/Cu/Ti wafer as a sputtered coating, typically about 100 nm thick. This substrate composition provides improved adhesion for epoxy-based photoresist materials, and particularly the photoresist material SU-8.

  7. Evaluation of over-etching technique in the endodontically treated tooth restoration

    PubMed Central

    Migliau, Guido; Piccoli, Luca; Besharat, Laith Konstantinos; Di Carlo, Stefano; Pompa, Giorgio

    2015-01-01

    Summary The main purpose of a post-endodontic restoration with posts is to guarantee the retention of the restorative material. The aim of the study was to examine, through the push-out test, how bond strength between the post and the dentin varied with etching time with 37% orthophosphoric acid, before cementation of a glass fiber post. Moreover, it has been examined if over-etching (application time of the acid: 2 minutes) was an effective technique to improve the adhesion to the endodontic substrate, after highlighting the problems of adhesion concerning its anatomical characteristics and the changes after the endodontic treatment. Highest bond strength values were found by etching the substrate for 30 sec., while over-etching didn’t improve bond strength to the endodontic substrate. PMID:26161247

  8. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    NASA Astrophysics Data System (ADS)

    Milly, Hussam; Andiappan, Manoharan; Thompson, Ian; Banerjee, Avijit

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  9. Comparison of marginal adaptation of mineral trioxide aggregate, glass ionomer cement and intermediate restorative material as root-end filling materials, using scanning electron microscope: An in vitro study

    PubMed Central

    Gundam, Sirisha; Patil, Jayaprakash; Venigalla, Bhuvan Shome; Yadanaparti, Sravanthi; Maddu, Radhika; Gurram, Sindhura Reddy

    2014-01-01

    Aim: The present study compares the marginal adaption of Mineral Trioxide Aggregate (MTA), Glass Ionomer Cement (GIC) and Intermediate Restorative Material (IRM) as root-end filling materials in extracted human teeth using Scanning Electron Microscope (SEM). Materials and Methods: Thirty single rooted human teeth were obturated with Gutta-percha after cleaning and shaping. Apical 3 mm of roots were resected and retrofilled with MTA, GIC and IRM. One millimeter transverse section of the retrofilled area was used to study the marginal adaptation of the restorative material with the dentin. Mounted specimens were examined using SEM at approximately 15 Kv and 10-6 Torr under high vacuum condition. At 2000 X magnification, the gap size at the material-tooth interface was recorded at 2 points in microns. Statistical Analysis: One way ANOVA Analysis of the data from the experimental group was carried out with gap size as the dependent variable, and material as independent variable. Results: The lowest mean value of gap size was recorded in MTA group (0.722 ± 0.438 μm) and the largest mean gap in GIC group (1.778 ± 0.697 μm). Conclusion: MTA showed least gap size when compared to IRM and GIC suggesting a better marginal adaptation. PMID:25506146

  10. Optimization of Cell Adhesion on Mg Based Implant Materials by Pre-Incubation under Cell Culture Conditions

    PubMed Central

    Willumeit, Regine; Möhring, Anneke; Feyerabend, Frank

    2014-01-01

    Magnesium based implants could revolutionize applications where orthopedic implants such as nails, screws or bone plates are used because they are load bearing and degrade over time. This prevents a second surgery to remove conventional implants. To improve the biocompatibility we studied here if and for how long a pre-incubation of the material under cell culture conditions is favorable for cell attachment and proliferation. For two materials, Mg and Mg10Gd1Nd, we could show that 6 h pre-incubation are already enough to form a natural protective layer suitable for cell culture. PMID:24857908

  11. Wear mechanism based on adhesion

    NASA Technical Reports Server (NTRS)

    Yamamoto, T.; Buckley, D. H.

    1982-01-01

    Various concepts concerning wear mechanisms and deformation behavior observed in the sliding wear track are surveyed. The mechanisms for wear fragment formation is discussed on the basis of adhesion. The wear process under unlubricated sliding conditions is explained in relation to the concept of adhesion at the interface during the sliding process. The mechanism for tearing away the surface layer from the contact area and forming the sliding track contour is explained by assuming the simplified process of material removal based on the adhesion theory.

  12. Light-curing time and aging effects on the nanomechanical properties of methacrylate- and silorane-based restorations.

    PubMed

    Catelan, A; Pollard, T; Bedran-Russo, Ak; Santos, Ph Dos; Ambrosano, Gmb; Aguiar, Fhb

    2014-01-01

    SUMMARY The aim of this study was to assess the influence of light-curing time on the nanohardness (H) and reduced elastic modulus (Er) of components (underlying dentin, hybrid layer, adhesive, and composite) of methacrylate- and silorane-based restorations after 24 hours and six months of storage. Class II slot preparations were carried out in human molars (n=3) and restored with methacrylate (Clearfil SE Bond [Kuraray] + Filtek Z250 [3M ESPE]) or silorane (LS restorative system [3M ESPE]) restorative systems and light-cured using light-emitting diode at 1390 mW/cm(2) for the recommended manufacturers' time or double time. Restorations were sectioned, and bonded dentin-resin interfaces were embedded in epoxy resin and polished for evaluation with a Berkovich fluid cell tip (TI 700 Ubi-1 nanoindenter, Hysitron). Data were statistically analyzed by analysis of variance and Tukey's test (alpha=0.05). Overall, the H and Er values were higher for methacrylate-based restorations than for silorane materials (p≤0.05), an increase in curing time did not improve the H and Er of the bonded interface components of either material (p>0.05), and aging significantly decreased the mechanical properties of interface components of both resin-based restorative systems (p≤0.05). In general, nanomechanical properties decreased after six months of storage, the methacrylate restorative system exhibited higher H and Er than silorane, and light-curing time did not influence the properties tested. PMID:24967984

  13. Bonding Durability of Four Adhesive Systems

    PubMed Central

    Seyed Tabai, Elaheh; Mohammadi Basir, Mahshid

    2015-01-01

    Objectives: This study aimed to compare the durability of four adhesive systems by assessing their microtensile bond strength (MTBS) and microleakage during six months of water storage. Materials and Methods: A total of 128 human third molars were used. The adhesives tested were Scotch Bond Multipurpose (SBMP), Single Bond (SB), Clearfil-SE bond (CSEB), and All-Bond SE (ABSE). After sample preparation for MTBS testing, the microspecimens were subjected to microtensile tester after one day and six months of water storage. For microleakage evaluation, facial and lingual class V cavities were prepared and restored with composite. After thermocycling, microleakage was evaluated. Bond strength values were subjected to one-way ANOVA and Tamhane’s test, and the microleakage data were analyzed by the Kruskal-Wallis, Dunn, Mann Whitney and Wilcoxon tests (P<0.05). Results: Single Bond yielded the highest and ABSE yielded the lowest bond strength at one day and six months. Short-term bond strength of SBMP and CSEB was similar. After six months, a significant decrease in bond strength was observed in ABSE and SBMP groups. At one day, ABSE showed the highest microleakage at the occlusal margin; however, at the gingival margin, there was no significant difference among groups. Long-term microleakage of all groups at the occlusal margins was similar, whilst gingival margins of SBMP and SB showed significantly higher microleakage. Conclusion: The highest MTBS and favorable sealability were obtained by Clearfil SE bond. Water storage had no effect on microleakage of self-etch adhesives at the gingival margin or MTBS of CSEB and SB. PMID:27123015

  14. A review of high-temperature adhesives

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; St.clair, T. L.

    1981-01-01

    The development of high temperature adhesives and polyphenylquinoxalines (PPQ) is reported. Thermoplastic polyimides and linear PPQ adhesive are shown to have potential for bonding both metals and composite structures. A nadic terminated addition polyimide adhesive, LARC-13, and an acetylene terminated phenylquinoxaline (ATPQ) were developed. Both of the addition type adhesives are shown to be more readily processable than linear materials but less thermooxidatively stable and more brittle. It is found that the addition type adhesives are able to perform, at elevated temperatures up to 595 C where linear systems fail thermoplastically.

  15. To Analyse the Erosive Potential of Commercially Available Drinks on Dental Enamel and Various Tooth Coloured Restorative Materials – An In-vitro Study

    PubMed Central

    Jindal, Ritu; Mahajan, Sandeep; Sandhu, Sanam; Sharma, Sunila; Kaur, Rajwinder

    2016-01-01

    Introduction With the enormous change in life style pattern of a common man through the past few decades, there has been proportional variation in the amount and frequency of consumption of drinks. An increased consumption of these drinks will concurrently increase enamel surface roughness by demineralization, resulting in hypersensitivity and elevated caries risk. Aim The present study was designed to evaluate the erosive potential of commercially available drinks on tooth enamel and various tooth coloured restorative materials. Materials and Methods Extracted human teeth were taken and divided into four groups i.e. tooth enamel, glass ionomer cement, composite and compomer. Four commercially available drinks were chosen these were Coca -Cola, Nimbooz, Frooti and Yakult. The pH of each drink was measured. Each group was immersed in various experimental drinks for a period of 14 days. The erosive potential of each drink was measured by calculating the change in average surface roughness of these groups after the immersion protocol in various drinks. The data analysis was done by One Way Anova, Post-Hoc Bonferroni, and paired t –test. Results Group II-GIC showed highest values for mean of change in average surface roughness and the values were statistically significant (p<0.001) with tooth enamel, composite and compomer (p=0.002). Coca-cola showed the highest erosive potential and Yakult showed the lowest, there was no statistical significant difference between the results shown by Yakult and Frooti. Conclusion Characteristics which may promote erosion of enamel and tooth coloured restorative materials were surface texture of the material and pH of the drinks. PMID:27437343

  16. Durable bonds at the adhesive/dentin interface: an impossible mission or simply a moving target?

    PubMed Central

    SPENCER, Paulette; Jonggu PARK, Qiang YE; MISRA, Anil; BOHATY, Brenda S.; SINGH, Viraj; PARTHASARATHY, Ranga; SENE, Fábio; de Paiva GONÇALVES, Sérgio Eduardo; LAURENCE, Jennifer

    2013-01-01

    Composite restorations have higher failure rates, more recurrent caries and increased frequency of replacement as compared to dental amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and failure. The gingival margin of composite restora tions is particularly vulnerable to decay and at this margin, the adhesive and its seal to dentin provides the primary barrier between the prepared tooth and the environment. The intent of this article is to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface. PMID:24855586

  17. Qualitative SEM/EDS analysis of microleakage and apical gap formation of adhesive root-filling materials

    PubMed Central

    SOUZA, Soraia de Fátima Carvalho; FRANCCI, Carlos; BOMBANA, Antonio C.; KENSHIMA, Silvia; BARROSO, Lúcia P.; D'AGOSTINO, Liz Z.; LOGUERCIO, Alessandro D.

    2012-01-01

    Objective The aim of this study was to compare the correspondence between gap formation and apical microleakage in root canals filled with epoxy resin-based (AH Plus) combined or not with resinous primer or with a dimethacrylate-based root canal sealer (Epiphany). Material and Methods Thirty-nine lower single-rooted human premolars were filled by the lateral condensation technique (LC) and immersed in a 50-wt% aqueous silver nitrate solution at 37ºC (24 h). After longitudinal sectioning, epoxy resin replicas were made from the tooth specimens. Both the replicas and the specimens were prepared for scanning electron microscopy (SEM). The gaps were observed in the replicas. Apical microleakage was detected in the specimens by SEM/energy dispersive spectroscopy (SEM/EDS). The data were analyzed statistically using an Ordinal Logistic Regression model and Analysis of Correspondence (α=0.05). Results Epiphany presented more regions containing gaps between dentin and sealer (p<0.05). There was correspondence between the presence of gaps and microleakage (p<0.05). Microleakage was similar among the root-filling materials (p>0.05). Conclusions The resinous primer did not improve the sealing ability of AH Plus sealer and the presence of gaps had an effect on apical microleakage for all materials. PMID:22858699

  18. Photoelastic analysis of stress generated by a silorane-based restoration system.

    PubMed

    Lopes, Murilo Baena; Valarini, Natália; Moura, Sandra Kiss; Guiraldo, Ricardo Danil; Gonini Júnior, Alcides

    2011-01-01

    Silorane-based composite, an epoxy material, was marketed as promising less polymerization contraction than conventional restorative materials. The aim of this study was to evaluate, by means of photoelasticity, the polymerization stress generated by a silorane-based composite. Thirty photoelastic rings with orifices measuring 5 mm (d) × 3 mm (h) were prepared and divided into 6 groups (n = 5) according to the material tested. The inside walls of the rings were sandblasted with aluminum oxide, after which the restorative materials were inserted into the orifices and photoactivated according to the manufacturer's instructions. The specimens were analyzed and the visual representation of the stress was measured considering the isochromatic ring of first order. The data were converted to MPa and subjected to ANOVA and Tukey's test (α= 0.05). The adhesive Filtek P-90 (G5) showed high contraction stress (p < 0.05) when compared to G1, G2, G3, G4, and G6, which did not differ from each other (p > 0.05). The composite Filtek P-90 showed similar contraction stress compared to the conventional composite and, additionally, its adhesive showed higher stress than did the etch-and-rinse 2-step adhesive. PMID:21860916

  19. Improving controllable adhesion on both rough and smooth surfaces with a hybrid electrostatic/gecko-like adhesive.

    PubMed

    Ruffatto, Donald; Parness, Aaron; Spenko, Matthew

    2014-04-01

    This paper describes a novel, controllable adhesive that combines the benefits of electrostatic adhesives with gecko-like directional dry adhesives. When working in combination, the two technologies create a positive feedback cycle whose adhesion, depending on the surface type, is often greater than the sum of its parts. The directional dry adhesive brings the electrostatic adhesive closer to the surface, increasing its effect. Similarly, the electrostatic adhesion helps engage more of the directional dry adhesive fibrillar structures, particularly on rough surfaces. This paper presents the new hybrid adhesive's manufacturing process and compares its performance to three other adhesive technologies manufactured using a similar process: reinforced PDMS, electrostatic and directional dry adhesion. Tests were performed on a set of ceramic tiles with varying roughness to quantify its effect on shear adhesive force. The relative effectiveness of the hybrid adhesive increases as the surface roughness is increased. Experimental data are also presented for different substrate materials to demonstrate the enhanced performance achieved with the hybrid adhesive. Results show that the hybrid adhesive provides up to 5.1× greater adhesion than the electrostatic adhesive or directional dry adhesive technologies alone. PMID:24451392

  20. Improving controllable adhesion on both rough and smooth surfaces with a hybrid electrostatic/gecko-like adhesive

    PubMed Central

    Ruffatto, Donald; Parness, Aaron; Spenko, Matthew

    2014-01-01

    This paper describes a novel, controllable adhesive that combines the benefits of electrostatic adhesives with gecko-like directional dry adhesives. When working in combination, the two technologies create a positive feedback cycle whose adhesion, depending on the surface type, is often greater than the sum of its parts. The directional dry adhesive brings the electrostatic adhesive closer to the surface, increasing its effect. Similarly, the electrostatic adhesion helps engage more of the directional dry adhesive fibrillar structures, particularly on rough surfaces. This paper presents the new hybrid adhesive's manufacturing process and compares its performance to three other adhesive technologies manufactured using a similar process: reinforced PDMS, electrostatic and directional dry adhesion. Tests were performed on a set of ceramic tiles with varying roughness to quantify its effect on shear adhesive force. The relative effectiveness of the hybrid adhesive increases as the surface roughness is increased. Experimental data are also presented for different substrate materials to demonstrate the enhanced performance achieved with the hybrid adhesive. Results show that the hybrid adhesive provides up to 5.1× greater adhesion than the electrostatic adhesive or directional dry adhesive technologies alone. PMID:24451392

  1. Do adhesive systems leave resin coats on the surfaces of the metal matrix bands? An adhesive remnant characterization.

    PubMed

    Arhun, Neslihan; Cehreli, Sevi Burcak

    2013-01-01

    Reestablishing proximal contacts with composite resins may prove challenging since the applied adhesives may lead to resin coating that produces additional thickness. The aim of this study was to investigate the surface of metal matrix bands after application of adhesive systems and blowing or wiping off the adhesive before polymerization. Seventeen groups of matrix bands were prepared. The remnant particles were characterized by energy dispersive spectrum and scanning electron microscopy. Total etch and two-step self-etch adhesives did not leave any resin residues by wiping and blowing off. All-in-one adhesive revealed resin residues despite wiping off. Prime and Bond NT did not leave any remnant with compomer. Clinicians must be made aware of the consequences of possible adhesive remnants on matrix bands that may lead to a defective definitive restoration. The adhesive resin used for Class II restorations may leave resin coats on metal matrix bands after polymerization, resulting in additional thickness on the metal matrix bands and poor quality of the proximal surface of the definitive restoration when the adhesive system is incorporated in the restoration. PMID:23484179

  2. Ceramic microstructure and adhesion

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1984-01-01

    When a ceramic is brought into contact with a ceramic, a polymer, or a metal, strong bond forces can develop between the materials. The bonding forces will depend upon the state of the surfaces, cleanliness and the fundamental properties of the two solids, both surface and bulk. Adhesion between a ceramic and another solid are discussed from a theoretical consideration of the nature of the surfaces and experimentally by relating bond forces to interface resulting from solid state contact. Surface properties of ceramics correlated with adhesion include, orientation, reconstruction and diffusion as well as the chemistry of the surface specie. Where a ceramic is in contact with a metal their interactive chemistry and bond strength is considered. Bulk properties examined include elastic and plastic behavior in the surficial regions, cohesive binding energies, crystal structures and crystallographic orientation. Materials examined with respect to interfacial adhesive interactions include silicon carbide, nickel zinc ferrite, manganese zinc ferrite, and aluminum oxide. The surfaces of the contacting solids are studied both in the atomic or molecularly clean state and in the presence of selected surface contaminants.

  3. Seventeen Years of Using Flowable Resin Restoratives--A Dental Practitioner's Personal Clinical Review.

    PubMed

    Firla, Markus Th

    2015-04-01

    Seen through the author's eyes on the basis of his practising dentistry for almost three decades, light-activated flowable resin restoratives (FRCs) or, in common clinical dental terminology, flowable composites have gradually gained major importance in restorative dentistry. Inputs to this ongoing trend are coming from continuous improvements in material properties and the favourable handling characteristics experienced with this particular group of restoratives. Intended to be used in direct adhesive filling procedures, the number and variety of recent generations of flowable composites for lining, restoration of all cavity classes (I-V), core build-ups and, more recently, 'bulk-fill-restorations', however, necessitates a profound clinical understanding of the selective use of flowable composites to ensure clinical success and guarantee long-term high quality results. Clinical relevance: Today's flowable composites allow for reliable restoration of all kinds of defects. However, both the handling characteristics and the material properties of FRCs must be fully understood before taking advantage of their potentially excellent clinical performance. PMID:26076545

  4. Fiber-matrix interface studies on bioabsorbable composite materials for internal fixation of bone fractures. I. Raw material evaluation and measurement of fiber-matrix interfacial adhesion.

    PubMed

    Slivka, M A; Chu, C C; Adisaputro, I A

    1997-09-15

    The objective of this study was to characterize and evaluate the performance of various fiber-matrix composite systems by studying the mechanical, thermal, and physical properties of the fiber and matrix components, and by studying the fiber-matrix interface adhesion strength using both microbond and fragmentation methods. The composites studies were poly(L-lactic acid) (PLLA) matrix reinforced with continuous fibers of either nonabsorbable AS4 carbon (C), absorbable calcium phosphate (CaP), poly(glycolic acid) (PGA), or chitin. Carbon and CaP single fibers had high Young's moduli and failed in a brittle manner. PGA and chitin single fibers had relatively lower Young's moduli and relatively higher ductility. Upon in vitro hydrolysis, CaP fibers retained 17% of their tensile strength and 39% of their Young's modulus after 12 h, PCA fibers retained 10% of their tensile strength and 52% of their Young's modulus after 16 days, and chitin fibers retained 87% of their tensile strength and 130% of their Young's modulus after 25 days. PLLA films had much lower strength and Young's moduli, but much higher ductility relative to the single fibers. Using the microbond method, the initial fiber-matrix interfacial shear strength (IFSS) of C/PLLA and CaP/PLLA microcomposites was 33.9 and 12.6 MPa, respectively. Upon in vitro hydrolysis, C/PLLA retained 49% of IFSS after 15 days and CaP/PLLA retained 46% of IFSS after 6 h. Using a fiber fragmentation method, the initial IFSS of C/PLLA, CaP/PLLA, and chitin/ PLLA was 22.2, 15.6, and 28.3 MPa, respectively. The performance of carbon fibers and C/PLLA composites was superior to the other fibers and fiber/PLLA systems, but the carbon fiber was nonabsorbable. CaP had the most suitable modulus of the absorbable fibers for fixing cortical bone fracture, but its rapid deterioration of mechanical properties and loss of IFSS limits its use. PGA and chitin fibers had suitable mechanical properties and their retention for fixing cancellous

  5. Fluorescence Reveals Contamination From Adhesives

    NASA Technical Reports Server (NTRS)

    Nikolia, William

    1992-01-01

    Contamination of nearby surfaces from ingredients in some adhesive materials detected by ultraviolet illumination and observation of resulting fluorescence. Identification of contaminants via telltale fluorescence not new; rather, significance lies in method of implementation and potential extension to wider variety of materials and applications.

  6. Shear Bond Strengths of Methacrylate- and Silorane-based Composite Resins to Feldspathic Porcelain using Different Adhesive Systems.

    PubMed

    Mohammadi, Narmin; Shakur Shahabi, Maryam; Kimyai, Soodabeh; Pournagi Azar, Fatemeh; Ebrahimi Chaharom, Mohammad Esmaeel

    2015-01-01

    Background and aims. Use of porcelain as inlays, laminates and metal-ceramic and all-ceramic crowns is common in modern dentistry. The high cost of ceramic restorations, time limitations and difficulty of removing these restorations result in delays in replacing fractured restorations; therefore, their repair is indicated. The aim of the present study was to compare the shear bond strengths of two types of composite resins (methacrylate-based and silorane-based) to porcelain, using three adhesive types. Materials and methods. A total of 156 samples of feldspathic porcelain surfaces were prepared with air-abrasion and randomly divided into 6 groups (n=26). In groups 1-3, Z250 composite resin was used to repair porcelain samples with Ad-per Single Bond 2 (ASB), Clearfil SE Bond (CSB) and Silorane Adhesive (SA) as the bonding systems, afterapplication of silane, respectively. In groups 4-6, the same adhesives were used in the same manner with Filtek Silorane composite resin. Finally, the shear bond strengths of the samples were measured. Two-way ANOVA and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at P<0.05. Results. There were significant differences in the mean bond strength values in terms of the adhesive type (P<0.001). In addition, the interactive effect of the adhesive type and composite resin type had no significant effect on bond strength (P=0.602). Conclusion. The results of the present study showed the highest repair bond strength values to porcelain with both composite resin types with the application of SA and ASB. PMID:26697151

  7. Shear Bond Strengths of Methacrylate- and Silorane-based Composite Resins to Feldspathic Porcelain using Different Adhesive Systems

    PubMed Central

    Mohammadi, Narmin; Shakur Shahabi, Maryam; Kimyai, Soodabeh; Pournagi Azar, Fatemeh; Ebrahimi Chaharom, Mohammad Esmaeel

    2015-01-01

    Background and aims. Use of porcelain as inlays, laminates and metal-ceramic and all-ceramic crowns is common in modern dentistry. The high cost of ceramic restorations, time limitations and difficulty of removing these restorations result in delays in replacing fractured restorations; therefore, their repair is indicated. The aim of the present study was to compare the shear bond strengths of two types of composite resins (methacrylate-based and silorane-based) to porcelain, using three adhesive types. Materials and methods. A total of 156 samples of feldspathic porcelain surfaces were prepared with air-abrasion and randomly divided into 6 groups (n=26). In groups 1-3, Z250 composite resin was used to repair porcelain samples with Ad-per Single Bond 2 (ASB), Clearfil SE Bond (CSB) and Silorane Adhesive (SA) as the bonding systems, afterapplication of silane, respectively. In groups 4-6, the same adhesives were used in the same manner with Filtek Silorane composite resin. Finally, the shear bond strengths of the samples were measured. Two-way ANOVA and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at P<0.05. Results. There were significant differences in the mean bond strength values in terms of the adhesive type (P<0.001). In addition, the interactive effect of the adhesive type and composite resin type had no significant effect on bond strength (P=0.602). Conclusion. The results of the present study showed the highest repair bond strength values to porcelain with both composite resin types with the application of SA and ASB. PMID:26697151

  8. The development of aerospace polyimide adhesives

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; St.clair, T. L.

    1983-01-01

    Few materials are available which can be used as aerospace adhesives at temperatures in the range of 300 C. The Materials Division at NASA-Langley Research Center developed several high temperature polyimide adhesives to fulfill the stringent needs of current aerospace programs. These adhesives are the result of a decade of basic research studies on the structure property relationships of both linear and addition aromatic polyimides. The development of both in house and commercially available polyimides is reviewed with regards to their potential for use as aerospace adhesives.

  9. Intraoral repair of cosmetic restorations.

    PubMed

    Denehy, G; Bouschlicher, M; Vargas, M

    1998-10-01

    The longevity of porcelain and composite resin restorations can often be prolonged by using sound principles, up-to-date materials, and judicious attention to repair when fracture problems arise. Careful case selection and correct usage of surface treatment agents, followed by the use of a quality bonding system and restorative materials, can result in a repair that exhibits excellent retention and natural color blending. This article outlines procedures and materials to repair both resin composite and porcelain intraorally. PMID:9891653

  10. A randomized clinical trial evaluating the success rate of ethanol wet bonding technique and two adhesives

    PubMed Central

    Mortazavi, Vajihesadat; Samimi, Pouran; Rafizadeh, Mojgan; Kazemi, Shantia

    2012-01-01

    Background: Composite resin restorations may have a short lifespan due to the degradation of resin–dentin interface. Ethanol wet bonding technique may extend the longevity of resin–dentin bond. The purpose of this one year randomized clinical trial was to compare clinical performance of two adhesives with ethanol wet bonding technique. Materials and Methods: This randomized clinical trial was performed on 36 non-carious cervical lesions in 12 patients restored with composite resin using one of the following approaches: 1. OptiBond FL (Kerr, USA); 2. Clearfil SE Bond (Kuraray, Japan) with enamel etching and 3. Ethanol wet bonding technique with the part of adhesive of OptiBond FL. The clinical success rate was assessed after 24 h, 6, 9 and 12 months according to the United States Public Health Service (USPHS) criteria: Marginal discoloration, marginal defect, retention rate, caries occurrence, and postoperative sensitivity. The tooth vitality was also assessed. Results: The retention rate was 100% at baseline and at 6 months follow up for all types of bonding protocols and was 91.67% at 9 and 12 months follow up for ethanol wet bonding group. None of the restorations in three groups showed marginal defects, marginal discoloration or caries occurrence and were vital after 12 months. There was no statistically significant difference between three groups after 12 months follow up (p value = 0.358). Conclusions: Composite restorations placed using ethanol wet bonding technique presented equal performance to the other groups. PMID:23559924

  11. Fibrillar Adhesive for Climbing Robots

    NASA Technical Reports Server (NTRS)

    Pamess, Aaron; White, Victor E.

    2013-01-01

    A climbing robot needs to use its adhesive patches over and over again as it scales a slope. Replacing the adhesive at each step is generally impractical. If the adhesive or attachment mechanism cannot be used repeatedly, then the robot must carry an extra load of this adhesive to apply a fresh layer with each move. Common failure modes include tearing, contamination by dirt, plastic deformation of fibers, and damage from loading/ unloading. A gecko-like fibrillar adhesive has been developed that has been shown useful for climbing robots, and may later prove useful for grasping, anchoring, and medical applications. The material consists of a hierarchical fibrillar structure that currently contains two levels, but may be extended to three or four levels in continuing work. The contacting level has tens of thousands of microscopic fibers made from a rubberlike material that bend over and create intimate contact with a surface to achieve maximum van der Waals forces. By maximizing the real area of contact that these fibers make and minimizing the bending energy necessary to achieve that contact, the net amount of adhesion has been improved dramatically.

  12. Restoring proximal caries lesions conservatively with tunnel restorations

    PubMed Central

    Chu, Chun-Hung; Mei, May L; Cheung, Chloe; Nalliah, Romesh P

    2013-01-01

    The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED) and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations. PMID:24019754

  13. Restorative Nurse Assistant. Instructor Guide.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    This curriculum material covers the basic orientation and necessary skills which would enable the practicing Certified Nurse Assistant to be trained as a Restorative Nurse Assistant. The shift in emphasis from maintenance care to restorative care in the long-term care setting has created a need for trained paraprofessionals who are competent in…

  14. A finite element study of teeth restored with post and core: Effect of design, material, and ferrule

    PubMed Central

    Upadhyaya, Viram; Bhargava, Akshay; Parkash, Hari; Chittaranjan, B.; Kumar, Vivek

    2016-01-01

    Background: Different postdesigns and materials are available; however, no consensus exists regarding superiority for stress distribution. The aim of this study was to evaluate the effect of design and material of post with or without ferrule on stress distribution using finite element analysis. Materials and Methods: A total of 12 three-dimensional (3D) axisymmetric models of postretained central incisors were made: Six with ferrule design and six without it. Three of these six models had tapered posts, and three had parallel posts. The materials tested were titanium post with a composite resin core, nickel chromium cast post and core, and fiber reinforced composite (FRC) post with a composite resin core. The stress analysis was done using ANSYS software. The load of 100 N at an angle of 45΀ was applied 2 mm cervical to incisal edge on the palatal surface and results were analyzed using 3D von Mises criteria. Results: The highest amount of stress was in the cervical region. Overall, the stress in the tapered postsystem was more than the parallel one. FRC post and composite resin core recorded minimal stresses within the post but the stresses transmitted to cervical dentin were more as compared to other systems. Minimal stresses in cervical dentine were observed where the remaining coronal dentin was strengthen by ferrule. Conclusion: A rigid material with high modulus of elasticity for post and core system creates most uniform stress distribution pattern. Ferrule provides uniform distribution of stresses and decreases the cervical stresses. PMID:27274343

  15. Ceramics in Restorative and Prosthetic DENTISTRY1

    NASA Astrophysics Data System (ADS)

    Kelly, J. Robert

    1997-08-01

    This review is intended to provide the ceramic engineer with information about the history and current use of ceramics in dentistry, contemporary research topics, and potential research agenda. Background material includes intra-oral design considerations, descriptions of ceramic dental components, and the origin, composition, and microstructure of current dental ceramics. Attention is paid to efforts involving net-shape processing, machining as a forming method, and the analysis of clinical failure. A rationale is presented for the further development of all-ceramic restorative systems. Current research topics receiving attention include microstructure/processing/property relationships, clinical failure mechanisms and in vitro testing, wear damage and wear testing, surface treatments, and microstructural modifications. The status of the field is critically reviewed with an eye toward future work. Significant improvements seem possible in the clinical use of ceramics based on engineering solutions derived from the study of clinically failed restorations, on the incorporation of higher levels of "biomimicry" in new systems, and on the synergistic developments in dental cements and adhesive dentin bonding.

  16. Prosthetic-restorative approach for the restoration of tooth wear. Vdo increase, rehabilitation of anatomy and function and aesthetic restoration of anterior teeth. Case report

    PubMed Central

    GARGARI, M.; CERUSO, F.M.; PRETE, V.; PUJIA, A.

    2012-01-01

    SUMMARY Prosthetic-restorative approach for the restoration of tooth wear. Case report Objective This article presents a case report of combined prosthetic-adhesive rehabilitation in a patient with a generalized tooth wear. Methods A combined treatment adhesive - prosthetic was proposed to a male patient of 65 years old having a clinically significant tooth wear, with dentine exposure and with a reduction in clinical crown height. The erosive/abrasive worn dentition have been reconstructed with direct resin composite restorations on the posterior teeth and with zirconia crown on the anterior teeth. Results Direct composite restorations have a number of distinct advantages. These restorations have proved durable and aesthetic, protect tooth structure and posterior occlusal contact is predictably re-established. Conclusions. A combinations of direct and indirect restorations, based on the new vertical dimension of occlusion (VDO), can help to reestablish anatomy and function. PMID:23285409

  17. The effectiveness of potent dental adhesives on the viability of LPS challenged human gingival fibroblasts.

    PubMed

    Garner, Angelia D; Tucci, Michelle A; Benghuzzi, Hamed A

    2014-01-01

    Dental adhesives are necessary for the retention of specific dental restorations utilized to repair the anatomy of the tooth after dental decay is removed. Adhesives come into contact with healthy and diseased periodontal tissues. Porphyromonas gingivalis is a gram negative bacterial pathogen, and lipopolysaccharide (LPS-PG) is an endotoxin found in gingival connective tissues of patients who suffer from periodontal disease. The presence of the endotoxin causes inflammation. This study aims to evaluate the effectiveness of potent dental adhesives when human gingival fibroblasts are challenged with LPS-PG. The fibroblasts were exposed to the dental adhesives polymethly methacrylate (PMMA), OptiBond®, and Prime & Bond® which were purchased from Patterson Dental, a national dental materials supplier. The human gingival fibroblasts (HGF-1, ATCC® CRL-2014™) were purchased from American Type Culture Collection (ATCC). The porphyromonas gingival lipopolysaccharide (LPS-PG) was purchased from Fisher Scientific (Pittsburg, PA). No significant differences in metabolic behavior was detected among the groups (p<0.132). While the glutathione assay determined that there was not any significant increase in oxidative stress levels; the lactate dehydrogenase assay identified significant cellular damage in the group exposed to combinations of the Prime & Bond® adhesives and LPS-PG at 48 hour intervals (p<0.003). No significant changes were noted in cellular morphology at any phases, and all cells demonstrated typical fibroblast spindle shape. PMID:25405402

  18. Effects of various chair-side surface treatment methods on dental restorative materials with respect to contact angles and surface roughness.

    PubMed

    Sturz, Candida R C; Faber, Franz-Josef; Scheer, Martin; Rothamel, Daniel; Neugebauer, Jörg

    2015-01-01

    Available chair-side surface treatment methods may adversely affect prosthetic materials and promote plaque accumulation. This study investigated the effects of treatment procedures on three resin restorative materials, zirconium-dioxide and polyetheretherketone in terms of surface roughness and hydrophobicity. Treatments were grinding with silicon carbide paper or white Arkansas stone, blasting with prophylaxis powder and polishing with diamond paste. Surface roughness was assessed using confocal laser scanning. Hydrophobicity as measured by water contact angle was determined by computerized image analysis using the sessile drop technique. All of the specific surface treatments performed led to significant changes in contact angle values and surface roughness (Ra) values. Median contact angle values ranged from 51.6° to 114°. Ra values ranged from 0.008 µm to 2.917 µm. Air-polishing as well as other polishing procedures increased surface roughness values in all materials except zirconium dioxide. Polyetheretherketone displayed greatest change in contact angle values after air-polishing treatment. PMID:26632228

  19. Natural restoration

    SciTech Connect

    Kamlet, K.S.

    1993-02-01

    After a company pays millions of dollars to clean up contaminated site, its liability may not be over. It may have to spend tens of millions more to restore damaged natural resources under an oft-overlooked Superfund program. Examples of liability are cited in this report from the Exxon Valdez oil spill and a pcb leak which contaminated a harbor.

  20. Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

    PubMed

    Jendresen, M D; Allen, E P; Bayne, S C; Hansson, T L; Klooster, J; Preston, J D

    1992-07-01

    The committee screened several hundred articles, citing 518 published papers. Some are present quality in research, others provide clinical interest, and some are identified as misleading. New techniques in pulp physiology and pathology are reported. Laser use and techniques in prevention, restorative dentistry, and materials use are reported. Epidemiology of selected diseases and the results of various formulations for treatment are cited. Diagnosis of craniomandibular dysfunction is well represented as well as references to literature reviews and other sophisticated scientific investigation. Research on adhesives is presented in respect to bonding agents for dentin and enamel. Several clinical studies are included, along with customary laboratory reports on several materials. PMID:1403904

  1. Properties of a glass-ionomer/resin-composite hybrid material.

    PubMed

    Mathis, R S; Ferracane, J L

    1989-09-01

    A small percentage of the liquid resin used in commercial dental composites was added to the liquid used in a commercial glass-ionomer restorative in order to produce a fluoride-containing hybrid restorative-type material that would adhere to dentin while being stronger, less brittle, and less sensitive to desiccation in the oral cavity than glass ionomer. Compressive strength, yield strength, elastic modulus, fracture toughness, and tensile strength were analyzed for this hybrid, light-cured material. In addition, the solubility in water, adhesion to dentin, and surface roughness were also examined in vitro. The results suggest that the early (one-hour) mechanical properties of the hybrid material exceed those of glass ionomer. In addition, the brittleness and solubility of the material are less than those of commercial glass ionomer, while adhesion to dentin is unaffected. Most importantly, surface crazing, a documented problem with some glass ionomers when they become desiccated, is alleviated with this hybrid formulation. PMID:2638281

  2. Mechanical retention versus bonding of amalgam and gallium alloy restorations.

    PubMed

    Eakle, W S; Staninec, M; Yip, R L; Chavez, M A

    1994-10-01

    The retention of amalgam and gallium alloy restorations in proximal box forms was measured in vitro, and three different adhesives to conventional undercuts were compared. For control, restorations were placed without undercuts or adhesives. No significant difference was found between amalgam and gallium alloys with each of the five methods of retention used. Alloys placed without retention or adhesives were significantly less retentive than all other groups. When Tytin alloy was used, no difference was found in retention among the restorations retained with Panavia or All-Bond adhesive or an occlusal dovetail and retention grooves, but Amalgambond adhesive was less retentive than all three of these methods. When gallium alloy was used, both Panavia and All-Bond adhesive were more retentive than undercuts, but the effect of Amalgambond adhesive was more retentive than undercuts, but the effect of Amalgambond adhesive was comparable to that of undercuts. The results of this study indicate that adhesives could be used in place of traditional undercuts to retain amalgam and gallium alloys, thus saving a considerable amount of tooth structure. PMID:7990038

  3. Restoring Ancestral Language, Restoring Identity.

    ERIC Educational Resources Information Center

    Bannon, Kay T.

    1999-01-01

    Describes the Cherokee Language Renewal Program that was designed to help Cherokee elementary school children learn to function in the dominant culture without sacrificing their own cultural heritage. Explains how the program got started, and reports on how it helps restore a cultural identify to a people who are at risk of losing their identity.…

  4. Interfacial adhesion - Theory and experiment

    NASA Technical Reports Server (NTRS)

    Ferrante, John; Banerjea, Amitava; Bozzolo, Guillermo H.; Finley, Clarence W.

    1988-01-01

    Adhesion, the binding of different materials at an interface, is of general interest to many branches of technology, e.g., microelectronics, tribology, manufacturing, construction, etc. However, there is a lack of fundamental understanding of such diverse interfaces. In addition, experimental techniques generally have practical objectives, such as the achievement of sufficient strength to sustain mechanical or thermal effects and/or have the proper electronic properties. In addition, the theoretical description of binding at interfaces is quite limited, and a proper data base for such theoretical analysis does not exist. This presentation will review both experimental and theoretical aspects of adhesion in nonpolymer materials. The objective will be to delineate the critical parameters needed, governing adhesion testing along with an outline of testing objectives. A distinction will be made between practical and fundamental objectives. Examples are given where interfacial bonding may govern experimental consideration. The present status of theory is presented along with recommendations for future progress and needs.

  5. Interfacial adhesion: Theory and experiment

    NASA Technical Reports Server (NTRS)

    Ferrante, John; Bozzolo, Guillermo H.; Finley, Clarence W.; Banerjea, Amitava

    1988-01-01

    Adhesion, the binding of different materials at an interface, is of general interest to many branches of technology, e.g., microelectronics, tribology, manufacturing, construction, etc. However, there is a lack of fundamental understanding of such diverse interfaces. In addition, experimental techniques generally have practical objectives, such as the achievement of sufficient strength to sustain mechanical or thermal effects and/or have the proper electronic properties. In addition, the theoretical description of binding at interfaces is quite limited, and a proper data base for such theoretical analysis does not exist. This presentation will review both experimental and theoretical aspects of adhesion in nonpolymer materials. The objective will be to delineate the critical parameters needed, governing adhesion testing along with an outline of testing objectives. A distinction will be made between practical and fundamental objectives. Examples are given where interfacial bonding may govern experimental consideration. The present status of theory is presented along wiith recommendations for future progress and needs.

  6. A Comparative Evaluation of the Amount of Fluoride Release and Re-Release after Recharging from Aesthetic Restorative Materials: An in vitro Study

    PubMed Central

    Bansal, Ruchika

    2015-01-01

    Aim To measure the amount of fluoride released and re released after recharging from various restorative materials: Conventional Glass Ionomer Cement (Fuji II), Light Cure Resin Modified GIC (Fuji II LC), Giomer (Beautifil II), Compomer (Dyract). Materials and Methods Fifteen cylindrical specimens were prepared from each material. The specimens were immersed in 20 ml of deionized water. The amount of released fluoride was measured during the 1st day, 7th day and on the day15 by using specific fluoride electrode and an ion-analyser. After 15 days each material was divided into three Sub Groups of five samples each. Sub Group A served as control, Sub Group B was exposed to 2% NaF solution, Sub Group C to 1000ppm F toothpaste. The amount of fluoride re-released was measured during the 1st day, 7th day and on the day15 by using specific fluoride electrode and an ion-analyser. The results were statistically analysed using analysis of variance (one-way ANOVA) and Tukey Kramer multiple comparison tests (p≤0.05). Results Independent of the observation time period of the study the Conventional GIC released the highest amount of fluoride followed by RMGIC, Giomer and Compomer. The initial burst effect was seen with GIC’S but not with Giomer and Compomer. After topical fluoride application fluoride re release was highest in Sub Group B and GIC had a greater recharging ability followed by RMGIC, Giomer and Compomer. The fluoride re release was greatest on 1st day followed by rapid return to near exposure levels. Conclusion From the study it was concluded that, the initial Fluoride release was highest from Conventional GIC followed by Resin Modified GIC, Giomer and Compomer. The Fluoride re release was high when recharging with professional regime (2% NaF) as compared to home regime (Toothpaste). Conventional GIC had a greater recharging ability followed by Resin Modified GIC, Giomer and Compomer. PMID:26436037

  7. Restoration Process

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the accompanying photos, a laboratory technician is restoring the once-obliterated serial number of a revolver. The four-photo sequence shows the gradual progression from total invisibility to clear readability. The technician is using a new process developed in an applications engineering project conducted by NASA's Lewis Research Center in conjunction with Chicago State University. Serial numbers and other markings are frequently eliminated from metal objects to prevent tracing ownership of guns, motor vehicles, bicycles, cameras, appliances and jewelry. To restore obliterated numbers, crime laboratory investigators most often employ a chemical etching technique. It is effective, but it may cause metal corrosion and it requires extensive preparatory grinding and polishing. The NASA-Chicago State process is advantageous because it can be applied without variation to any kind of metal, it needs no preparatory work and number recovery can be accomplished without corrosive chemicals; the liquid used is water.

  8. Tensile and shear strength of adhesives

    NASA Technical Reports Server (NTRS)

    Stibolt, Kenneth A.

    1990-01-01

    This experiment is conducted in a freshman-level course: Introduction to Engineering Materials. There are no prerequisites for the course although students should have some knowledge of basic algebra. The objectives are to tension and shear test adhesives and to determine the tensile and shear properties of adhesives. Details of equipment of procedure are given.

  9. Adhesive curing through low-voltage activation

    PubMed Central

    Ping, Jianfeng; Gao, Feng; Chen, Jian Lin; Webster, Richard D.; Steele, Terry W. J.

    2015-01-01

    Instant curing adhesives typically fall within three categories, being activated by either light (photocuring), heat (thermocuring) or chemical means. These curing strategies limit applications to specific substrates and can only be activated under certain conditions. Here we present the development of an instant curing adhesive through low-voltage activation. The electrocuring adhesive is synthesized by grafting carbene precursors on polyamidoamine dendrimers and dissolving in aqueous solvents to form viscous gels. The electrocuring adhesives are activated at −2 V versus Ag/AgCl, allowing tunable crosslinking within the dendrimer matrix and on both electrode surfaces. As the applied voltage discontinued, crosslinking immediately terminated. Thus, crosslinking initiation and propagation are observed to be voltage and time dependent, enabling tuning of both material properties and adhesive strength. The electrocuring adhesive has immediate implications in manufacturing and development of implantable bioadhesives. PMID:26282730

  10. Functionally Graded Adhesives for Composite Joints

    NASA Technical Reports Server (NTRS)

    Stapleton, Scott E.; Waas, Anthony M.; Arnold, Steven M.

    2012-01-01

    Adhesives with functionally graded material properties are being considered for use in adhesively bonded joints to reduce the peel stress concentrations located near adherend discontinuities. Several practical concerns impede the actual use of such adhesives. These include increased manufacturing complications, alterations to the grading due to adhesive flow during manufacturing, and whether changing the loading conditions significantly impact the effectiveness of the grading. An analytical study is conducted to address these three concerns. An enhanced joint finite element, which uses an analytical formulation to obtain exact shape functions, is used to model the joint. Furthermore, proof of concept testing is conducted to show the potential advantages of functionally graded adhesives. In this study, grading is achieved by strategically placing glass beads within the adhesive layer at different densities along the joint.

  11. Thermal Characterization of Adhesive

    NASA Technical Reports Server (NTRS)

    Spomer, Ken A.

    1999-01-01

    The current Space Shuttle Reusable Solid Rocket Motor (RSRM) nozzle adhesive bond system is being replaced due to obsolescence. Down-selection and performance testing of the structural adhesives resulted in the selection of two candidate replacement adhesives, Resin Technology Group's Tiga 321 and 3M's EC2615XLW. This paper describes rocket motor testing of these two adhesives. Four forty-pound charge motors were fabricated in configurations that would allow side by side comparison testing of the candidate replacement adhesives and the current RSRM adhesives. The motors provided an environment where the thermal performance of adhesives in flame surface bondlines was compared. Results of the FPC testing show that: 1) The phenolic char depths on radial bond lines is approximately the same and vary depending on the position in the blast tube regardless of which adhesive was used; 2) The adhesive char depth of the candidate replacement adhesives is less than the char depth of the current adhesives; 3) The heat-affected depth of the candidate replacement adhesives is less than the heat-affected depth of the current adhesives; and 4) The ablation rates for both replacement adhesives are slower than that of the current adhesives.

  12. Materials Science and Technology, Volume 14, Materials Science and Technology A Comprehensive Treatment - Volume 14: Medical and Dental Materials Cahn,R.W.(ed.)/Haasen,P.(ed.)/Kramer,E.J.(ed.)

    NASA Astrophysics Data System (ADS)

    Williams, David F.

    1996-12-01

    The applications of metals, ceramics, and polymers in medical and dental engineering is becoming ever more widespread. Technologists in these fields are provided with a unique overview of materials, performances and applications. From the Contents: Williams: Biofunctionality and Biocompatibility. Kohn/Ducheyne: Materials for Bone and Joint Replacement. Baquey: Materials in the Cardiovascular System. Aebischer/Goddard/ Galletti/ Lysaght: Biomaterials and Artificial Organs. Yannas: Materials for Skin and Nerve Regeneration. Watts: Dental Restorative Materials. Williams: Materials for Oral and Maxillofacial Surgery/Materials for Ophthalmology. Causton: Medical and Dental Adhesives. Reichert/Saavedra: Materials Consideration in the Selection, Performance, and Adhesion of Polymeric Encapsulants for Implantable Sensors. Campbell/Jones: Materials for Implantable Electrodes and Electronic Devices. Brunstedt/Anderson: Materials for Drug Delivery. Jones: Materials for Fixed and Removable Prosthodontics.

  13. A Comparative Study of Microleakage on Dental Surfaces Bonded with Three Self-Etch Adhesive Systems Treated with the Er:YAG Laser and Bur

    PubMed Central

    Sanhadji El Haddar, Youssef; Cetik, Sibel; Bahrami, Babak; Atash, Ramin

    2016-01-01

    Aim. This study sought to compare the microleakage of three adhesive systems in the context of Erbium-YAG laser and diamond bur cavity procedures. Cavities were restored with composite resin. Materials and Methods. Standardized Class V cavities were performed in 72 extracted human teeth by means of diamond burs or Er-YAG laser. The samples were randomly divided into six groups of 12, testing three adhesive systems (Clearfil s3 Bond Plus, Xeno® Select, and Futurabond U) for each method used. Cavities were restored with composite resin before thermocycling (methylene blue 2%, 24 h). The slices were prepared using a microtome. Optical microscope photography was employed to measure the penetration. Results. No statistically significant differences in microleakage were found in the use of bur or laser, nor between adhesive systems. Only statistically significant values were observed comparing enamel with cervical walls (p < 0.001). Conclusion. It can be concluded that the Er:YAG laser is as efficient as diamond bur concerning microleakage values in adhesive restoration procedures, thus constituting an alternative tool for tooth preparation. PMID:27419128

  14. A Comparative Study of Microleakage on Dental Surfaces Bonded with Three Self-Etch Adhesive Systems Treated with the Er:YAG Laser and Bur.

    PubMed

    Sanhadji El Haddar, Youssef; Cetik, Sibel; Bahrami, Babak; Atash, Ramin

    2016-01-01

    Aim. This study sought to compare the microleakage of three adhesive systems in the context of Erbium-YAG laser and diamond bur cavity procedures. Cavities were restored with composite resin. Materials and Methods. Standardized Class V cavities were performed in 72 extracted human teeth by means of diamond burs or Er-YAG laser. The samples were randomly divided into six groups of 12, testing three adhesive systems (Clearfil s(3) Bond Plus, Xeno® Select, and Futurabond U) for each method used. Cavities were restored with composite resin before thermocycling (methylene blue 2%, 24 h). The slices were prepared using a microtome. Optical microscope photography was employed to measure the penetration. Results. No statistically significant differences in microleakage were found in the use of bur or laser, nor between adhesive systems. Only statistically significant values were observed comparing enamel with cervical walls (p < 0.001). Conclusion. It can be concluded that the Er:YAG laser is as efficient as diamond bur concerning microleakage values in adhesive restoration procedures, thus constituting an alternative tool for tooth preparation. PMID:27419128

  15. Nanorough titanium surfaces reduce adhesion of Escherichia coli and Staphylococcus aureus via nano adhesion points.

    PubMed

    Lüdecke, Claudia; Roth, Martin; Yu, Wenqi; Horn, Uwe; Bossert, Jörg; Jandt, Klaus D

    2016-09-01

    Microbial adhesion to natural and synthetic materials surfaces is a key issue e.g. in food industry, sewage treatment and most importantly in the biomedical field. The current development and progress in nanoscale structuring of materials surfaces to control microbial adhesion requires an advanced understanding of the microbe-material-interaction. This study aimed to investigate the nanostructure of the microbe-material-interface and link it to microbial adhesion kinetics as function of titanium surface nanoroughness to gain new insight into controlling microbial adhesion via materials' surface nanoroughness. Adhesion of Escherichia coli and Staphylococcus aureus was statistically significantly reduced (p≤0.05) by 55.6 % and 40.5 %, respectively, on physical vapor deposited titanium thin films with a nanoroughness of 6nm and the lowest surface peak density compared to 2nm with the highest surface peak density. Cross-sectioning of the microbial cells with a focused ion beam (FIB) and SEM imaging provided for the first time direct insight into the titanium-microbe-interface. High resolution SEM micrographs gave evidence that the surface peaks are the loci of initial contact between the microbial cells and the material's surface. In a qualitative model we propose that the initial microbial adhesion on nanorough surfaces is controlled by the titanium surface peak density via nano adhesion points. This new understanding will help towards the design of materials surfaces for controlling microbial adhesion. PMID:27288816

  16. Class II Resin Composites: Restorative Options.

    PubMed

    Patel, Minesh; Mehta, Shamir B; Banerji, Subir

    2015-10-01

    Tooth-coloured, resin composite restorations are amongst the most frequently prescribed forms of dental restoration to manage defects in posterior teeth. The attainment of a desirable outcome when placing posterior resin composite restorations requires the clinician to have a good understanding of the benefits (as well as the limitations) posed by this material, together with a sound knowledge of placement technique. Numerous protocols and materials have evolved to assist the dental operator with this type of demanding posterior restoration. With the use of case examples, four techniques available are reported here. CPD/Clinical Relevance: This article explores varying techniques for the restoration of Class II cavities using resin composite. PMID:26685471

  17. A randomized double-blind clinical trial of posterior composite restorations with or without bevel: 1-year follow-up

    PubMed Central

    COELHO-DE-SOUZA, Fábio Herrmann; CAMARGO, Junara Cristina; BESKOW, Tiago; BALESTRIN, Matheus Dalmolin; KLEIN-JÚNIOR, Celso Afonso; DEMARCO, Flávio Fernando

    2012-01-01

    Objective This randomized double-blind clinical trial compared the performance of posterior composite restorations with or without bevel, after 1-year follow-up. Material and Methods Thirteen volunteers requiring at least two posterior composite restorations were selected. Twenty-nine cavities were performed, comprising 14 without bevel (butt joint) and 15 with bevel preparation of the enamel cavosurface angle. All cavities were restored with simplified adhesive system (Adper Single Bond) and composite resin (Filtek P60). A halogen light curing unit was used through the study. Restorations were polished immediately. Analysis was carried out at baseline, after 6 months and after 1 year by a calibrated evaluator (Kappa), according to the FDI criteria. Data were statistically analyzed by Mann-Whitney test (p<0.05). Results Beveled and non-beveled cavities performed similarly after 1 year follow-up, regarding to fractures and retention, marginal adaptation, postoperative hypersensitivity, recurrence of caries, surface luster and anatomic form. However, for surface and marginal staining, beveled cavities showed significantly better performance (p<0.05) than butt joint restorations. Conclusions It was concluded that the restorations were acceptable after 1 year, but restorations p