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1

[Glass ionomer cementing in stomatological practice].  

PubMed

Glass ionomers cements represent a cement system which develops by a reaction between a polyalchenic acid, usually a homo- or a copolymer of acrylic acid and a ion donor, usually an aluminium fluorosilicate glass. Introduction of these ionomers in the stomatological practice was determined by their remarkable adherence to dentin, by pulpal and parodontal biocompatibility, and because of the fact that they deliver continuously fluorine over a long period of time. These cements provide a good marginal sealing of the obturation. In the last years a new generation of glass ionomers cements has been introduced, that "Cormat" cements, in which the glass powder is intimately linked to a pure silver metallic powder by a synthetization process, and this provides a greatly increased resistance to abrasion, as compared to conventional glass ionomer cements. Presently glass ionomer cements have become increasingly known in the stomatological practice and they are used preferentially for base obturations, under obturations with composites on lateral teeth, in the treatment of mylolysis and for coronary erosions determined by brushing, which do not need preparation of retention cavities. They are also used for coronary reconstruction, and the treatment of atopical microcavities of occluding decay processes on the lateral teeth that have induced limited enamel losses. The perspective of these cements in the stomatological practice depends however on an improved translucency, which, for the present at least, does not match that of silicates and composites, as well as on an improved resistance to bending, and even the "Cormat" cements are inferior to silver amalgam which is used in the obturation of classical class II cavities. PMID:2101262

Andreescu, C; Iliescu, A

2

Devitrification of ionomer glass and its effect on the in vitro biocompatibility of glass-ionomer cements.  

PubMed

The effects of devitrification of an ionomer glass with a molar composition 4.5SiO(2).3Al(2)O(3).1.5P(2)O(5).3CaO.2CaF(2) on cement formation and in vitro biocompatibility were investigated. Differential thermal analysis was used to study the phase evolution in the glass, and to determine the heat treatments for production of glass-ceramics. X-ray diffraction patterns from glass frit heat-treated at 750 degrees C for 2h contained peaks corresponding to apatite (JCPDS 15-876), whereas for samples heat-treated at 950 degrees C for 2h apatite and mullite (JCPDS 15-776) were the major phases detected. Transmission electron microscopy (TEM) confirmed that apatite and apatite-mullite phases were present after heat treatments at 750 degrees C and 950 degrees C respectively. Glass and glass-ceramics were ground to prepare <45microm powders and glass ionomer cements were produced using a ratio of 1g powder: 0.2g PAA: 0.3g 10% m/v tartaric acid solution in water. In vitro biocompatibility was evaluated using cultured rat osteosarcoma (ROS) cells. Scanning electron microscopy (SEM) showed that cells colonised the surfaces of cements prepared using untreated ionomer glass and glass crystallised to form apatite (750 degrees C/2h). However, quantitative evaluation using MTT and total protein assays indicated that more cell growth occurred in the presence of cements prepared using ionomer glasses crystallised to apatite than cements prepared using untreated glass. The least cell growth and respiratory activity was observed on cements made with crystallised glass containing both apatite and mullite. It was concluded that the controlled devitrification of ionomer glasses could be used to produce GIC bone cements with improved biocompatibility. PMID:12895588

Hurrell-Gillingham, K; Reaney, I M; Miller, C A; Crawford, A; Hatton, P V

2003-08-01

3

Development of glass-ionomer cement systems  

Microsoft Academic Search

In the 1960s the idea of positive physico-chemical adhesion with tooth substance resulted in the invention of polyacrylic acid-based cements, first the zinc polycarboxylate and, subsequently, the glass-ionomer cements. These materials were shown to undergo specific adhesion with hydroxyapatite and proved to have properties satisfactory for a variety of clinical applications. The key properties of the glass-ionomer cements—fluoride release over

Dennis C. Smith

1998-01-01

4

[The use of glass ionomer cements in endodontics].  

PubMed

Glass ionomer cements are currently used in endodontic therapy for sealing root canals (orthogradely and retrogradely), for sealing and restoring the pulp chamber, for repairing perforations and root resorption defects, and, rarely, for treating vertically fractured teeth. The successful use of these cements is the result of their particular characteristics: a chemical bond to dentin, which enhances the seal of the root canal and the reinforcement of the tooth; a good biocompatibility in the periradicular area and a fluoride release without loss of strength of the material. The fluoride release imparts an antimicrobial effect to combat root canal infection and attributes to bone mineralization after surgery. The present paper reviews the literature regarding the various applications of glass ionomer cements in present-day endodontics. PMID:11505760

De Moor, R; De Bruyne, M

2000-01-01

5

In vitro Characteristics of a Glass Ionomer Cement  

PubMed Central

Glass ionomer cements were first described by Wilson and Kent and have been used in dentistry since 1969. It has been recommended for bridging ossicular chain defects, fixation of ossicular chain prosthesis, anchoring of cochlear implants, mastoid obliteration, and repair of tegmen and posterior canal wall defects. The biocompatability and stability of this material over time is vital to its usefulness in neurotologic surgery. The purpose of this study was to assess the stability of a glass ionomer cement in the presence of bacteria and in different pH environments. We demonstrated that bacteria readily adhere to the surface and their presence is associated with accelerated loss of matrix. We found the cement to be susceptible to low pH and to release a visible cloud of debris upon contact with fluid. Calcium concentration in the solution was elevated at all pH levels. Although we are able to demonstrate these findings in vitro the clinical relevance is unclear. There have been several cases of aseptic meningitis possibly due to intracranial release of components of the cement. Until further studies are done use of the cement in contact with cerebral spinal fluid should be avoided. This cement, or a similar material, would be useful in neurotologic surgery but prior to widespread use further testing should be done to assess safety. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 9Figure 10Figure 11

Driscoll, Colin L. W.; Green, J. Douglas; Beatty, Charles W.; McCaffrey, Thomas V.; Marrs, Christopher D.

1998-01-01

6

Devitrification of ionomer glass and its effect on the in vitro biocompatibility of glass-ionomer cements  

Microsoft Academic Search

The effects of devitrification of an ionomer glass with a molar composition 4.5SiO2·3Al2O3·1.5P2O5·3CaO·2CaF2 on cement formation and in vitro biocompatibility were investigated. Differential thermal analysis was used to study the phase evolution in the glass, and to determine the heat treatments for production of glass-ceramics. X-ray diffraction patterns from glass frit heat-treated at 750°C for 2h contained peaks corresponding to

K Hurrell-Gillingham; I. M Reaney; C. A Miller; A Crawford; P. V Hatton

2003-01-01

7

Dimensional changes occurring in a glass-ionomer cement.  

PubMed

The dimensional changes occurring when glass ionomer cements are exposed both to desiccating and moist conditions were investigated. All work was done at 23 degrees C. The effect of time allowed for cements to mature before exposure to the test conditions was studied as was the effect of adding cellulose ethers. The contraction of glass ionomer cements under desiccating conditions was far greater than the expansion by water absorption. Increase of the time allowed for the cements to mature reduced the extent of this effect markedly. The addition of cellulose ethers to cement mixes was only moderately effective in reducing dimensional change. PMID:7880475

Wilson, A D; Paddon, J M

1993-12-01

8

Mechanical properties and microstructures of glass-ionomer cements  

Microsoft Academic Search

Objective: The objective of this study was to determine the flexural strength (FS), compressive strength (CS), diametral tensile strength (DTS), Knoop hardness (KHN) and wear resistance of ten commercial glass-ionomer cements (GICs). The fracture surfaces of these cements were examined using scanning electron microscopic (SEM) techniques to ascertain relationships between the mechanical properties and microstructures of these cements.Methods: Specimens were

D. Xie; W. A. Brantley; B. M. Culbertson; G. Wang

2000-01-01

9

Advanced antibacterial glass ionomer cements for improved dental restoratives  

Microsoft Academic Search

Secondary caries that often occurs at the interface between the restoration and the cavity preparation is mainly caused by demineralization of tooth structure due to invasion of plaque bacteria (acid-producing bacteria) such as Streptococcus mutans (S. mutans) in the presence of fermentable carbohydrates. Although glass-ionomer cements (GICs) are found to be the most cariostatic and somehow antibacterial due to release

Yiming Weng

2011-01-01

10

Short-term mechanical properties of glass ionomer cement  

Microsoft Academic Search

The setting reaction of glass ionomer cement was studied by analyzing and comparing the short-tem mechanical properties of\\u000a set cement stored in silicone oil, air and distilled water respectively at different temperatures. For the set cement stored\\u000a at 37 °C, the strength of the sample in the air reached the maximum value after 24 h, then decreased to about 210

Sanbao Tang; Dongxuan Xu

2009-01-01

11

Toughening of dental glass ionomer cements with reactive glass fibres.  

PubMed

A fibre reinforced glass ionomer cement (FRGIC) for dental applications was loaded with 20 vol% short fibres (430 microm) with a glass composition in the system SiO(2)-Al(2)O(3)-CaF(2)-Na(3)AlF(6). The fracture toughness and the total energy release rate were examined. A 20% anisotropic fibre alignment was observed, perpendicular to the loading direction. An increase of fracture toughness of 140% and of total energy release rate of 440% was achieved compared to the unreinforced glass ionomer cement. Matrix-fibre interface reaction is supposed to exert the major influence on mechanical behaviour of FRGIC by controlling fibre pull-out and thus the total energy release rate. PMID:15110473

Lohbauer, Ulrich; Frankenberger, Roland; Clare, Alexis; Petschelt, Anselm; Greil, Peter

2004-10-01

12

Ion release by endodontic grade glass-ionomer cement  

Microsoft Academic Search

Cylindrical specimens (6 mm high × 4 mm diameter) of the endodontic grade glass-ionomer (Ketac Endo) were exposed to various\\u000a media for 1 week, after which changes in their mass, pH of storage medium, and ion release were determined. In water, this\\u000a cement was shown to release reasonable amounts of sodium, aluminium and silicon, together with smaller amounts of calcium

Beata Czarnecka; Honorata Limanowska-Shaw; Richard Hatton; John W. Nicholson

2007-01-01

13

Investigation of glass-ionomer cements using differential scanning calorimetry.  

PubMed

Six commercial glass-ionomer cements commonly used for various dental applications have been investigated using differential scanning calorimetry (DSC). The heat-flow behaviour and heat capacity of the cements were measured during isothermal (at 37 degrees C) setting reactions. The DSC results show that all materials undergo an exothermic setting process, but with different enthalpies of reactions and different heat capacities; there are no remaining endo- or exothermic reactions after the setting of the cement. All materials examined were found to be effective thermal insulators. PMID:15348851

Khalil, S K; Atkins, E D

1998-09-01

14

Fluoride Release by Glass Ionomer Cements, Compomer and Giomer  

PubMed Central

Background: To measure the amounts of fluoride released from fluoride-containing materials, four glass ionomer cements (Fuji IX, Fuji VII, Fuji IX Extra and Fuji II LC), a compomer (Dyract Extra) and a giomer (Beautifil) were used in this study. Methods: Twenty cylindrical specimens were prepared from each material. The amount of released fluoride was measured during the first week and on the days 14 and 21 by using specific fluoride electrode and an ionanalyzer. The results were statistically analyzed using analysis of variance (two-way ANOVA) and Tukey Kramer multiple comparison tests (p=0.05). Results: Significant differences were seen in fluoride release of different days and materials (p<0.05). The maximum cumulative fluoride release of days 1-7 was related to Fuji VII, followed by Fuji IX Extra, Fuji II LC, Fuji IX, Dyract Extra and Beautifil in descending order and this order remained the same until the 21st day. Conclusion: Fuji IX, Fuji VII, Fuji IX Extra, and Fuji II LC released higher amounts of fluoride compared to Beautifil and Dyract Extra in this study. It seems that the extent of the glass ionomer matrix plays an important role in determining the fluoride releasing ability of glass ionomer cement materials.

Mousavinasab, Sayed Mostafa; Meyers, Ian

2009-01-01

15

Resin-Modified Glass-Ionomer Dental Cements Field of the Invention.  

National Technical Information Service (NTIS)

Resin-modified glass-ionomer cements are provided comprising polyelectrolyte-based cements and compatible vinyl monomers and/or polymers. The composites can be further crosslinked by free-radical chemical or photochemical polymerization in addition to the...

J. M. Antonucci J. E. McKinney J. W. Stansbury

1988-01-01

16

Buonocore Memorial Lecture. Glass-ionomer cements: past, present and future.  

PubMed

It was Michael Buonocore who focused the attention of the profession on adhesion in the oral cavity. He expanded the concept of adhesion of resins to enamel and investigated adhesion to dentin. The problem has been solved through the glass-ionomer cements rather than with resins, but sadly, he did not live to see them achieve maturity. The glass-ionomer cements were introduced to the profession in 1976, and they provide adhesion to both enamel and dentin through an ion exchange with the additional benefit of a continuing fluoride release throughout the life of the restoration. Solubility is low, abrasion resistance is high, and biocompatability is excellent. As a water-based material, they have an excellent chance of survival in the hostile environment of the oral cavity. Acceptance of the early versions was slow because of perceived problems with water exchange, a poor color range, and a lack of translucency. Considerable research has been carried out over the last 20 years by members of the profession and the manufacturers; at this point, the glass-ionomer cements make a very valuable contribution to everyday practice. They are now available as both an autocure and a dual-cure cement, and the color range and translucency are excellent. Problems of clinical placement have been overcome, and it is now a simple matter to take advantage of the adhesion and the fluoride release and place a restoration that is esthetic, resistant to microleakage, long lasting, and a deterent to recurrent caries. Their only limitation lies in the fact that they lack the fracture strength to rebuild marginal ridges and incisal corners. In spite of this limitation, they have opened the way for the introduction of a new range of microcavity designs that allow for conservation of remaining tooth structure to an extent never before available. In the near future physical properties will be improved still further, and the use of these cements will expand considerably. PMID:9028245

Mount, G J

17

The co-cured, light-activated glass-ionomer cement-composite resin restoration.  

PubMed

The simultaneous curing of unpolymerized composite resin and inactivated light-curing glass-ionomer cement appears to offer a number of clinical improvements to the laminated glass-ionomer cement-composite resin restoration. The observation that composite resin cures before the glass-ionomer cement suggests that the polymerization shrinkage of the resin may be taken up by the uncured glass-ionomer cement, reducing the internal stress of the restoration. A procedure is described for the placement of this type of laminate restoration that reduces both technique sensitivity and placement time, by eliminating a number of the steps required for a conventional "sandwich" restoration. The apparent clinical success of this technique indicates the need for laboratory testing to evaluate the potential of this procedure. PMID:8183983

Knight, G M

1994-02-01

18

Caries protection after orthodontic band cementation with glass ionomer.  

PubMed

This study evaluated the resistance of the enamel to an artificial caries challenge after removing orthodontic bands cemented with a glass ionomer cement (GIC). Ten extracted caries-free molars were cleaned with a slurry of pumice and randomly divided into 2 groups of 5 teeth each: Group 1: Cementation with GIC (Fuji) and Group 2: Cementation with a zinc phosphate cement (Mizzy). Both cements were handled according to manufacturer's instructions. Before cementing the bands, an area of S x S mm was masked with adhesive tape on the lingual surfaces of all teeth. The orthodontic bands were cemented over this adhesive tape. After band cementation, the occlusal and gingival margins of the band were delineated with a bur on the tooth surface. The teeth were thermocycled (200 cycles, 5-55 degrees C, 30-second dwell time) and stored in distilled water for 24 hours. Then, the bands and adhesive tape were removed and the teeth again stored in distilled water for a week, changing the water daily. The teeth were then varnished with the exception of a 5 x 5 mm window (including previously exposed and covered areas) on the buccal and lingual surfaces. All teeth were then placed in an acidified gel (pH 4.5) for 5 weeks to produce artificial caries. At least three sections from the exposed and covered areas were made from the buccal and lingual challenged areas. Sections were ground to approximately 100 microns. Polarized microscopy and image analysis were used to analyze the results.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8258573

Marcushamer, M; Garcia-Godoy, F; Chan, D C

19

Chlorhexidine release from an experimental glass ionomer cement.  

PubMed

Glass ionomer cements (GIC) can potentially be used as matrices for the slow release of active species, as has been shown previously for fluoride ions. This study investigated the use of an experimental GIC as a carrier for the release of chlorhexidine acetate (CHA) at included concentrations ranging from 0.5% to 13.0% of CHA by weight. Release into water was examined using high-performance liquid chromatography. All measurable chlorhexidine was released within 22 h1/2, however this was less than 10% of the total mass incorporated in the specimens. An increased percentage of CHA incorporated into the powder gave an increased release into the surrounding water. The bulk of the CHA was retained within the cement. For comparison, the surface chemistry of a CHA-containing GIC was examined using X-ray photoelectron spectroscopy before and after prolonged immersion in water. This confirmed retention of a large amount of CHA. Spectra after leaching appeared very similar to those from a CHA-free GIC after immersion in a CHA solution. In order to explore the effect of CHA-inclusion on the cement properties, compressive strengths, working and setting times were also measured. In general, compressive strengths were found to be decreased in direct proportion to the quantity of CHA added, while working and setting times increased. PMID:15130727

Palmer, G; Jones, F H; Billington, R W; Pearson, G J

2004-10-01

20

Glass-ionomer cement restorative materials: a sticky subject?  

PubMed

Glass-ionomer cement (GIC) materials have been in clinical use since their inception 40 years ago. They have undergone several permutations to yield different categories of these materials. Although all GICs share the same generic properties, subtle differences between commercial products may occur. They have a wide range of uses such as lining, bonding, sealing, luting or restoring a tooth. In general, GICs are useful for reasons of adhesion to tooth structure, fluoride release and being tooth-coloured although their sensitivity to moisture, inherent opacity, long-term wear and strength are not as adequate as desired. They are useful in situations where they are not disadvantaged by their comparatively lower physical properties, such as where there is adequate remaining tooth structure to support the material and where they are not subject to heavy occlusal loading. The last decade has seen the use of these materials being extended. However, they are likely to retain their specific niches of clinical application. PMID:21564113

Sidhu, S K

2011-06-01

21

Effects of polycarboxylate and glass ionomer cements on stainless steel crown retention  

Microsoft Academic Search

Retentive properties of three dental cements were tested using stainless steel crowns Fitted to extracted third molar teeth. No significant difference was Found between the overall mean retentive Forces of the polycarboxylate cement and the two glass ionomer cements. Mechanical retention of the crowns was not a Factor in the overall retentive value.

David P. Noffsinger; Joseph R. Jedrychowski; Angelo A. Caputo

1983-01-01

22

Development of an experimental glass ionomer cement containing niobium and fluoride  

Microsoft Academic Search

Glass ionomer cements (GICs) are currently used for various dental applications such as luting cements or as restorative materials. The calcium fluoro-alumino-silicate system is the basis for degradable glasses used to obtain the GICs. The purpose of the present paper is to add niobium to conventional glass system because according to previous papers niobium addition improves the chemical resistance and

Marcio José Bertolini; Maria Aparecida Zaghete; Rossano Gimenes

2005-01-01

23

The processing, mechanical properties and bioactivity of zinc based glass ionomer cements  

Microsoft Academic Search

The suitability of Glass Ionomer Cements (GICs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of a GIC and its absence is likely to hinder cement formation. However, zinc oxide, a bacteriocide, can act both as a network modifying

D. Boyd; M. R. Towler

2005-01-01

24

[Glass ionomer cement and "sandwich" restorations after two years of clinical service].  

PubMed

Esthetic restorations for class V lesions extending into root dentin often show marginal discoloration after some time. In this clinical study the long term quality of glass ionomer cement and "sandwich" restorations was compared with each other. In 19 patients 83 class V lesions with the apical margin in dentin were restored with glassionomer cement (I: Fuji II/G-C Dental; II: Ketac Fil/ESPE) or with a glass ionomer liner (III: Lining Cement/G-C Dental; IV: Ketac Bond/ESPE) and laminated with a composite. Where necessary the margins were prepared apically with a butt joint. The observation period between placement and last follow-up check varied between 18 and 44 months. Modified Ryge criteria were used for the clinical assessment of 77 restorations. Marginal quality was assessed in the SEM using replicas. 15.8% of the "sandwich" type and 5% of the glass ionomer cement restorations were lost. All restored teeth remained vital. Clinically the best marginal quality was found with a glass ionomer cement (II) whereas only two thirds of the sandwich restorations and the other glassionomer cement (I) had perfect margins. In the SEM the glassionomer cements had significantly less marginal openings than one of the sandwich restorations (III). PMID:1814714

Reich, E

1991-02-01

25

Dispersive surface properties of glass-ionomer cements determined by inverse gas chromatography  

NASA Astrophysics Data System (ADS)

The surface properties of several glass-ionomer cements (GIC), restorative dental materials, (GC-Fuji, Chemadent G-J, Ketac Fil and Ketac Molar) were investigated for the first time by means of inverse gas chromatography. This method enables characterization of surface activity in dispersive (non-polar) and acid base interactions. The ability of the surface of glass-ionomers to participate in dispersive interactions was expressed by the use of the dispersive component of surface free energy ?sd. This parameter was determined with satisfactory precision, meaning that the values of ?sd can be further used in the discussion of the influence of the type of GIC, its preparation and the storage time on the surface properties. The greatest capacity for dispersive interactions was revealed by Ketac Molar and the lowest by GC-Fuji. Dispersive interactions in the surface activity of glass-ionomers increased with increasing storage time after cement preparation.

Andrzejewska, E.; Voelkel, A.; Andrzejewski, M.; Limanowska-Shaw, H.

2005-05-01

26

The Effect of Glass Ionomer and Adhesive Cements on Substance P Expression in Human Dental Pulp.  

PubMed

Objectives. The purpose of this study was to quantify the effect of glass ionomer and adhesive cements on SP expression in healthy human dental pulp. Study Design. Forty pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic reasons. In thirty of these premolars a Class V cavity preparation was performed and teeth were equally divided in three groups: Experimental Group I: Glass Ionomer cement was placed in the cavity. Experimental Group II: Adhesive Cement was placed in the cavity. Positive control group: Class V cavities only. The remaining ten healthy premolars where extracted without treatment and served as a negative control group. All pulp samples were processed and SP was measured by radioimmunoassay. Results. Greater SP expression was found in the adhesive cement group, followed by the glass ionomer and the positive control groups. The lower SP values were for the negative control group. ANOVA showed statistically significant differences between groups (p<0.0001). Tukey HSD post hoc tests showed statistically significant differences in SP expression between negative control group and the 3 other groups (p<0.01). Differences between the cavity-only group and the two experimental groups were also statistically significant (p<0.05 and p<0.01 respectively). There is also a statistically significant difference between the two experimental groups (p<0.01). Conclusion. These findings suggest that adhesive cements provoke a greater SP expression when compared with glass ionomer. PMID:23722145

Caviedes-Bucheli, J; Ariza-Garcia, G; Camelo, P; Mejia, M; Ojeda, K; Azuero-Holguin, M-M; Abad-Coronel, D; Munoz, H-R

2013-05-31

27

Caries inhibition by a resin-modified and a conventional glass ionomer cement, in vitro  

Microsoft Academic Search

Objectives: The aim of this study was to compare inhibition, in vitro, of a resin-modified and a conventional glass ionomer cement.Methods: Standardized Class V cavities were prepared in extracted human molar teeth and restored with Fuji II LC (n = 14) or Chemfil II (n = 14) according to manufacturers' guidelines. The teeth were submerged in an acid gel (lactic

S. M. Dunne; J. S. Goolnik; B. J. Millar; R. P. Seddon

1996-01-01

28

Gingival Reactions Around and Plaque Formation on Resin Composites and Glass-Ionomer Cements  

Microsoft Academic Search

This review covers plaque growth on and gingival reactions adjacent to composite resin and glass-ionomer cement restorations. Despite large variations in surface roughness and chemical composition of the restoratives, no clinically measurable differences in the presence or development of plaque and gingivitis were seen. However, more pronounced signs of subclinical gingivitis adjacent to resin composites, compared with non-filled surfaces, were

J. W. V. Van Dijken; S. Sjostrom

1995-01-01

29

Clinical comparison of postoperative sensitivity for a glass ionomer and a zinc phosphate luting cement  

Microsoft Academic Search

In 60 patients, 120 partial and full-coverage restorations were cemented on vital abutment teeth with either a glass ionomer or a zinc phosphate luting cement. A split-mouth design and a patient blind data acquisition protocol were used. During an average observation period of 17.3 months there were no differences between the two types of luting cements in regard to subjective

Matthias Kern; Brigitte Kleimeier; Hans-Günther Schaller; Jörg Rudolf Strub

1996-01-01

30

Incorporation of Casein Phosphopeptide-Amorphous Calcium Phosphate into a Glass-ionomer Cement  

Microsoft Academic Search

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) nanocomplexes have been shown to prevent demineralization and promote remineralization of enamel subsurface lesions in animal and in situ caries models. The aim of this study was to determine the effect of incorporating CPP-ACP into a self-cured glass-ionomer cement (GIC). Incorporation of 1.56% w\\/w CPP-ACP into the GIC significantly increased microtensile bond strength (33%) and

S. A. Mazzaoui; M. F. Burrow; M. J. Tyas; S. G. Dashper; D. Eakins; E. C. Reynolds

2003-01-01

31

Interaction of resin-modified glass-ionomer cements with moist dentine  

Microsoft Academic Search

Objectives. The objective of this study was to report on a novel phenomenon that occurs when resin-modified glass-ionomer cements (RMGICs) are bonded to moist human dentine.Methods. Dentine surfaces from extracted third molars were abraded with 180-grit SiC paper. Ten teeth were prepared for each of the two RMGICs tested (Fuji II LC, GC Corp. and Photac-Fil Quick, 3M ESPE). RMGIC

C. K. Y Yiu; F. R Tay; N. M King; D. H Pashley; R. M Carvalho; M. R. O Carrilho

2004-01-01

32

Dissolution behavior and fluoride release from new glass composition used in glass ionomer cements  

Microsoft Academic Search

The degradability in an acidic environment and the release of different ions, such as Na+, Ca2+, Al3+ and F? from a calcium fluoro-aluminosilicate glass (used in glass ionomer cements) during different exposure times at 37°C has been the object of this study. The formation of a leached layer on the surface of the glass has proved to be an important

Jhamak Nourmohammadi; Reza Salarian; Mehran Solati-Hashjin; Fatollah Moztarzadeh

2007-01-01

33

Reactivity of Fluoride-containing Calcium Aluminosilicate Glasses Used in Dental Glass-ionomer Cements  

Microsoft Academic Search

The glass component critically determines the properties of glass-ionomer cements (GIC). However, the exact relationship between the composition of the glass and these properties is not yet fully understood. To investigate this relationship, we studied the reactivity of glasses used in commercial GIC in acetic acid solutions, using a pH-stat method. Qualitative differences in the leaching behavior of these glasses

E. A. P. De Maeyer; R. M. H. Verbeeck; C. W. J. Vercruysse

1998-01-01

34

Non metallic restorative materials based on glass ionomer cements — recent trends and developments  

Microsoft Academic Search

In this contribution to a series of papers dealing with the colloid chemistry and structure of restorative and luting material for dentistry we will present a short introduction into the state-of-the-art of applying and developing dental material based on glass ionomer cement (GIC). The basic component of glass of GIC and related material is a glass-like calcium aluminosilicate containing some

R Zimehl; M Hannig

2000-01-01

35

Effect of sample preparation on the in vitro genotoxicity of a light curable glass ionomer cement  

Microsoft Academic Search

The glass ionomer cement Vitrebond™ showed a clear genotoxic effect in the in vitro Mammalian Cell Gene Mutation Test (HPRT Test) with CHO cells as well as in the bacterial umu-test with Salmonella typhimurium TA1535\\/pSK1002. Both DMSO and Ham's F12 cell culture medium extracts according to ISO 10993-12 (Biological evaluation of medical devices—Part 12: sample preparation and reference materials, Geneva,

B. P Müller; A Eisenträger; W Jahnen-Dechent; W Dott; J Hollender

2003-01-01

36

Comparison of incus interpositioning technique versus glass ionomer cement application in type 2 tympanoplasty.  

PubMed

Objective of this study is to compare glass ionomer cement application and incus interpositioning techniques in patients who have chronic otitis media, conductive hearing loss with intact tympanic membrane and who undergo hearing reconstruction of staged surgery using a retrospective chart review in the setting of Ministry of Health Ankara Training and Research Hospital ENT Clinic, Turkey. We retrospectively evaluated patients who underwent otological surgery and hearing reconstruction with auto graft incus during 2005-2008 or glass ionomer cement during 2008-2010. Patients who had cholesteatoma, stapes fixation and tympanosclerosis were excluded. Postoperative mean follow-up time of 107 patients was 9.8 months (6-38 months, 83.2 % of them was ? 9 months). Postoperative pure tone hearing thresholds, graft status, gain scores and air bone gaps were recorded. Intact graft, dry ear on the operated side and ABG scores less than 20 dB were accepted as surgical success. Preoperative ABG score was 30.6 ± 7.93 dB in glass ionomer (group I) and 33.6 ± 11.99 dB in incus interpositioning (group II). Postoperative ABG scores were 13.6 ± 10.40 and 22.6 ± 12.39 dB, respectively, in group I and II. Success of closure in ABG scores was obtained in both groups (p < 0.001). Gain scores in group I were better (p = 0.035). Graft success (p = 0.020) correlated with gain score. Results showed that the glass ionomer cement application is a good, cost-effective technique, easy to perform and yields better hearing scores and lower complication rates compared to incus interpositioning technique. PMID:23010791

Yaz?c?, Ha?met; Uzunkulao?lu, Hakk?; Emir, Hatice Karadas; K?z?lkaya, Zeynep; Do?an, Sedat; Samim, Erdal

2012-08-04

37

The effect of oxalic acid incorporation on the setting time and strength of a glass-ionomer cement  

Microsoft Academic Search

Oxalic acid and its metal oxalate salts have been used extensively in dentistry in a range of applications: as desensitisers, in cavity preparation, and as bonding agents. This study investigated the influence of oxalic acid upon the working time, initial setting time, 24-h hardness and compressive strength of a glass-ionomer cement. Conventional glass-ionomer liquids were prepared from polyacrylic acid, tartaric

Leon Hugh Prentice; Martin Tyas

2006-01-01

38

Microleakage under orthodontic bands cemented with nano-hydroxyapatite-modified glass ionomer.  

PubMed

Objectives: To estimate the in vivo effect of nano-hydroxyapatite (HA) modification of banding glass-ionomer cement on microleakage under orthodontic bands. Materials and Methods: Eighty noncarious premolars scheduled for extraction in 20 orthodontic patients were randomly divided into four groups. Grouping was based on the ratio of nano-HA (0%, 5%, 10%, 15% by weight) added to the luting glass-ionomer cement (GIC) Ketac-Cem, which was used for cementation of prefabricated micro-etched orthodontic bands. Dye penetration method was used for microleakage evaluation at the cement-band and cement-enamel interfaces. Statistical evaluation was performed with a Kruskal-Wallis test and a Mann-Whitney U-test, and a Bonferroni-adjusted significance level was calculated. Results: Bands cemented with conventional GIC showed the highest microleakage scores in comparison to those cemented with nano-HA-modified GIC. No significant difference was found between teeth banded with 10% and 15% modified GIC. Conclusions: Modification of the banding GIC with 15% nano-HA revealed a positive effect on reducing microleakage around orthodontic bands. PMID:23745977

Enan, Enas T; Hammad, Shaza M

2013-06-01

39

The structure of a glass-ionomer cement and its relationship to the setting process.  

PubMed

The G-200 glass of the glass-ionomer cement has two phases: a continuous calcium aluminosilicate matrix and partly crystalline calcium fluoride-rich droplets, the nature of which depend on the thermal history of the glass. The setting process of the cement takes place when the glass is mixed with poly(acrylic acid). It has two overlapping stages corresponding to the rapid leaching of calcium ions from the uncrystalline part of the droplets, followed by the slower release of aluminum (and some calcium) from the main glass phase. These processes are affected by the microstructure and microcomposition of the glass. PMID:284041

Barry, T I; Clinton, D J; Wilson, A D

1979-03-01

40

A comparison of the in vitro cytotoxicity of conventional and resin modified glass ionomer cements.  

PubMed

To evaluate cytotoxicity of experimental conventional and resin modified glass-ionomer cements on UMR-106 osteoblast cell cultures and cell cultures of NIH(3)T(3) mouse fibroblasts specimens were prepared for every experimental material and divided into: group 1.Conventional glass-ionomer cements: GC Fuji IX GP Fast, GC Fuji Triage and Ketac Silver; group 2. Resin modified glass-ionomer cements: GC Fuji II LC, GC Fuji Plus and Vitrebond; group 3. Positive control was presented by specimens of composite Vit-l-ecence® and negative control-group 4. was presented by ?-minimum essential medium for UMR-106 - osteoblast-like cells and Dulbecco's Modified Eagle's Medium for NIH(3)T(3) mouse fibroblast cells. Both cell cultures were exposed to 10% of eluate of each single specimen of each experimental material. Experimental dishes were incubated for 24 h. Cell metabolism was evaluated using methyltetrazolium assay. Kruskal-Wallis test and Tukey-Kramer post hoc test for the materials evaluated on NIH(3)T(3) mouse fibroblast cells, as well as UMR-106 osteoblast-like cells showed significantly more cytotoxicity of RMGICs, predominantly Vitrebond to both GICs and composite- Vit-l-ecence®.The lowest influence on cell's metabolism on UMR-106 osteoblas-like cells was shown by Ketac Silver and the lowest influence on cell's metabolism on NIH(3)T(3) mouse fibroblast cells was shown by Fuji IX GP Fast. Statistical evaluation of sensitivity of cell lines UMR-106 osteoblast-like cells and NIH(3)T(3) mouse fibroblast cells, using Mann-Whitney test, showed that NIH(3)T(3) mouse fibroblast cells were more sensitive for the evaluation of cytotoxicity of dental materials. PMID:23198945

Selimovi?-Dragaš, Mediha; Huseinbegovi?, Amina; Kobašlija, Sedin; Hatibovi?-Kofman, Sahza

2012-11-01

41

Effect of heat application on the mechanical behaviour of glass ionomer cements.  

PubMed

OBJECTIVES: The aim of this study was to examine the long-term effect of heat on the mechanical behaviour of conventional highly viscous glass ionomer cements. Besides, the effect of storage time was evaluated. MATERIALS AND METHODS: Five cements (ChemFil Rock, Riva Self Cure, Fuji IX GP Fast, Equia and Ketac Molar Aplicap) were evaluated using three different preparation methods: no heat application, application of heat by means of a LED curing unit for 20 and 60 s. Four hundred fifty bar-shaped specimens were produced, maintained in distilled water at 37 °C and tested after 1 week, 1 month and 3 months (n?=?10). The Vickers hardness, indentation modulus and creep were measured. In addition, the amount and size of the glass fillers and voids were examined using a light and a scanning electron microscope. RESULTS: Fuji IX GP Fast showed the highest Vickers hardness, Ketac Molar Aplicap showed the highest indentation modulus and the best value of creep was measured for Riva Self Cure. Vickers hardness, modulus of elasticity and creep resistance increased most for ChemFil Rock and Equia up to 1-month storage. CONCLUSIONS: Heat application showed no effect on the mechanical behaviour of ChemFil Rock, Fuji IX GP Fast and Equia at all ageing time. The impact of storage duration was low. CLINICAL RELEVANCE: Considering the measured mechanical properties, there is no need of using heat when restoring teeth with glass ionomer cements. PMID:23740319

Menne-Happ, Ulrike; Ilie, Nicoleta

2013-06-01

42

Aluminum-free glass-ionomer bone cements with enhanced bioactivity and biodegradability.  

PubMed

Al-free glasses of general composition 0.340SiO2:0.300ZnO:(0.250-a-b)CaO:aSrO:bMgO:0.050Na2O:0.060P2O5 (a, b=0.000 or 0.125) were synthesized by melt quenching and their ability to form glass-ionomer cements was evaluated using poly(acrylic acid) and water. We evaluated the influence of the poly(acrylic acid) molecular weight and glass particle size in the cement mechanical performance. Higher compressive strength (25±5 MPa) and higher compressive elastic modulus (492±17 MPa) were achieved with a poly(acrylic acid) of 50 kDa and glass particle sizes between 63 and 125 ?m. Cements prepared with glass formulation a=0.125 and b=0.000 were analyzed after immersion in simulated body fluid; they presented a surface morphology consistent with a calcium phosphate coating and a Ca/P ratio of 1.55 (similar to calcium-deficient hydroxyapatite). Addition of starch to the cement formulation induced partial degradability after 8 weeks of immersion in phosphate buffer saline containing ?-amylase. Micro-computed tomography analysis revealed that the inclusion of starch increased the cement porosity from 35% to 42%. We were able to produce partially degradable Al-free glass-ionomer bone cements with mechanical performance, bioactivity and biodegradability suitable to be applied on non-load bearing sites and with the appropriate physical characteristics for osteointegration upon partial degradation. Zn release studies (concentrations between 413 ?M and 887 ?M) evidenced the necessity to tune the cement formulations to reduce the Zn concentration in the surrounding environment. PMID:23827583

Gomes, Filipa O; Pires, Ricardo A; Reis, Rui L

2012-12-13

43

Sealing ability of mineral trioxide aggregate, glass ionomer cement and composite resin when repairing large furcal perforations  

Microsoft Academic Search

Objective To evaluate the sealing ability of different repair materials and the pathway of bacterial penetration after closure of large pulp chamber floor perforations. Materials and methods Perforations were made in the furcation area of extracted human molars and sealed with either mineral trioxide aggregate (MTA), glass ionomer cement or resin composite. The bacterial leakage method was used with Enterococcus

M. Kleivmyr; E. Bruzell; D. Ørstavik; G. Lodiene

2011-01-01

44

Summary of: Sealing ability of mineral trioxide aggregate, glass ionomer cement and composite resin when repairing large furcal perforations  

Microsoft Academic Search

Objective To evaluate the sealing ability of different repair materials and the pathway of bacterial penetration after closure of large pulp chamber floor perforations.Materials and methods Perforations were made in the furcation area of extracted human molars and sealed with either mineral trioxide aggregate (MTA), glass ionomer cement or resin composite. The bacterial leakage method was used with Enterococcus faecalis

Asgeir Bårdsen

2011-01-01

45

Preparation and evaluation of an experimental luting glass ionomer cement to be used in dentistry.  

PubMed

The aim of this paper is to compare the fluoride-releasing and mechanical properties of an experimental luting glass ionomer cement, which has a modified composition and a commercial luting cement. The experimental powder was obtained by sol-gel process and then, it was used to prepare the experimental cements. The properties of cement pastes, such as setting time and working time, microhardness and diametral tensile strength were determined. Fluoride release from GICs was evaluated at time intervals of 1, 7, 14, 21 and 28 days in deionized water. Atomic force microscopy (AFM) analyses showed that the surface of the experimental cements is more homogeneous than commercial GICs. The mechanical properties and the measure of liberation of fluoride of the two cements were influenced by ratio powder:liquid and chemical composition of the precursor powders. Experimental cements released less fluoride than commercial cements. However, this liberation was more constant during the analyzed period. Thus, the results obtained in this study indicated that the composition of the experimental powder modified by the niobium can lead the formation of the polysalt matrix with good mechanical properties. In other words, we can say that experimental powder offered considerable promise for exploitation in dental field. PMID:19415231

Bertolini, M J; Zaghete, M A; Gimenes, R; Padovani, G C; Cruz, C A S

2009-05-05

46

Long-term fluoride release from a glass ionomer cement, a compomer, and from experimental resin composites.  

PubMed

The aqueous phase of glass ionomer cements enables fluoride ions to diffuse and to be released from the material. The matrix of resin composites is much less hydrophilic, and fluoride incorporated in the material is only released in small amounts. It was the purpose of the present work to study the influence of resin matrix formulation on the fluoride release from experimental, fluoride-containing resin composites. The resin composites were based on methacrylate monomers and the adduct of maleic anhydride and HEMA (2-hydroxyethyl methacrylate). The resin composites contained 1 w% or 5 w% of AlF3*3H2O. A glass ionomer cement and a compomer were used as controls. Five disks of each material were stored in distilled water at room temperature. By means of a fluoride sensitive electrode, the fluoride release from disk-shaped specimens was determined periodically over 3 years. The glass ionomer cement released the most fluoride (1.54 +/- 4 microg/cm2 after 1 year and 248 +/- 7 microg/cm2 after 3 years). The compomer released relatively little fluoride during the 1st year (30 +/- 1 microg/cm2) but after this time the rate of fluoride release became equal to that of the glass ionomer cement, resulting in a release of 122 +/- 8 microg/cm2 after 3 years. Regarding the resin composites, the fluoride release increased with the hydrophilicity and the acid character of the polymer matrix. The release, however, was significantly lower than that from the glass ionomer cement and the compomer and ranged from 1.2 +/- 0.07 to 42 +/- 3.9 microg/cm2 at 1 year and from 2.3 +/- 0.16 to 79 +/- 6 microg/cm2 at 3 years. PMID:12020121

Asmussen, Erik; Peutzfeldt, Anne

2002-03-01

47

Effect of glass-ionomer cement on the progression of proximal caries.  

PubMed

Although effective preventive strategies exist for pit and fissure caries, prevention of proximal caries remains a significant challenge. This split-mouth study was designed to investigate the effect of glass-ionomer cement (GIC) on the progression of initial proximal caries in posterior teeth, testing the hypothesis that local application of fluoride-releasing GIC would reduce this progression. GIC was applied to 41 pairs of posterior teeth after elastic band separation in 7- to 19-year-old individuals. Follow-up bitewing radiographs were taken at 6 and 12 months. Differences in ? mean lesion depth at 6 and 12 months between test and control groups were significant (p < 0.05, p < 0.000). Lesions treated with GIC were more likely to remain in or regress to the outer half of enamel (OR = 6.3; 95%CI, 1.3-30.9). GIC provides an effective approach to the clinical management of incipient proximal caries. PMID:20858776

Trairatvorakul, C; Itsaraviriyakul, S; Wiboonchan, W

2010-09-21

48

Glass ionomer cement as an occlusive barrier in Class III furcation defect.  

PubMed

Predicting the prognosis of molars that have experienced furcation invasion, is often a frustrating experience to the dental clinician and disappointing report to the patient involved. Although multiple treatment modalities have been attempted to retain teeth with severe furcation invasion, clinical success has not been predictable. A case report involving the use of glass ionomer cement (GIC) as an occlusive barrier in the management of Class III furcation defect involving mandibular first molar is presented. A literature review on the subject matter was conducted using Medline, Google search engines, and manual library search. GIC restoration of Class III furcation invasion gives a satisfactory result. Surgical and nonsurgical treatment options are available for the management of the condition. GIC as an occlusive barrier in Class III furcation invasion is an economical and less invasive treatment option. It also makes home care easy for the patient. PMID:22124057

Singhal, Rameshwari

49

Comparison of glass ionomer cement and incus interposition in reconstruction of incus long process defects.  

PubMed

The ossicles may be affected through the mass effect of the pathological tissue in chronic otitis media. Ossicular reconstruction may be accomplished using the patients' own ossicles or with alloplastic materials. Glass ionomer ossiculoplasty is a fast, efficient, safe and cost-effective method and it has been used more frequently in recent years. Forty-six patients who had surgery for chronic otitis media were included in this study. All patients had an incus long process defect and a normal stapes superstructure. Ossicular reconstruction was performed using glass ionomer cement (GIC) (Ketac-Cem, Espe Dental AG, Seefeld, Germany) in 23 patients (group 1), while incus interposition was performed in other 23 patients (group 2). Preoperative and postoperative air pure tone averages of the group 1 patients were 42.8 and 35.2 dB, respectively (p < 0.01). These values were 42.9 and 34.5 dB in group 2 (p < 0.01). Two groups were similar with respect to postoperative hearing gain (p > 0.05). The air bone gap of group 1 was 27 dB preoperatively and 20.7 dB postoperatively. These values were 28.7 and 20.2 dB, respectively, in group 2. The closure of air bone gap was statistically significant in both the groups (p < 0.01, p < 0.01). The comparison of the mean gains of the air bone gap revealed no difference between the groups (p > 0.05). In conclusion, the use of both GIC ossiculoplasty and incus interposition are efficient methods for reconstruction of incus long process and one is not superior to the other. A larger study population may be useful for comparison of these methods. PMID:21340562

Dere, Huseyin; Ozdogan, Fatih; Ozcan, K Murat; Selcuk, Adin; Ozcan, Ibrahim; Gokturk, Gokhan

2011-02-22

50

Use of Raman spectroscopy in the characterisation of the acid–base reaction in glass-ionomer cements  

Microsoft Academic Search

Raman spectra of various combinations of glass-ionomer cement components have been compared with those of the reactants and the salts of polyacrylic and tartaric acids. The components consisted of a fast-setting acid-degradable dental glass (containing, inter alia, oxides of Si, Al, Ca, Ba and Na), polyacrylic acid (PAA) and\\/or tartaric acid (TA). On the addition of water to the glass

A. M Young; A Sherpa; G Pearson; B Schottlander; D. N Waters

2000-01-01

51

Influence of powder\\/liquid mixing ratio on the performance of a restorative glass-ionomer dental cement  

Microsoft Academic Search

The influence of powder\\/liquid mixing regime on the performance of a hand-mixed restorative glass-ionomer cement (GIC) was evaluated in terms of compressive strength, working characteristics and the porosity distribution.Mean compressive fracture strengths, standard deviations and associated Weibull moduli (m) were determined from series of 20 cylindrical specimens (6mm height, 4mm diameter) prepared by hand-mixing the relative proportions of the powder

Garry J. P. Fleming; Ahmed A. Farooq; Jake E. Barralet

2003-01-01

52

Synthesis of a proline-modified acrylic acid copolymer in supercritical CO2 for glass-ionomer dental cement applications.  

PubMed

Supercritical (sc-) fluids (such as sc-CO(2)) represent interesting media for the synthesis of polymers in dental and biomedical applications. Sc-CO(2) has several advantages for polymerization reactions in comparison to conventional organic solvents. It has several advantages in comparison to conventional polymerization solvents, such as enhanced kinetics, being less harmful to the environment and simplified solvent removal process. In our previous work, we synthesized poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone) (PAA-IA-NVP) terpolymers in a supercritical CO(2)/methanol mixture for applications in glass-ionomer dental cements. In this study, proline-containing acrylic acid copolymers were synthesized, in a supercritical CO(2) mixture or in water. Subsequently, the synthesized polymers were used in commercially available glass-ionomer cement formulations (Fuji IX commercial GIC). Mechanical strength (compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS)) and handling properties (working and setting time) of the resulting modified cements were evaluated. It was found that the polymerization reaction in an sc-CO(2)/methanol mixture was significantly faster than the corresponding polymerization reaction in water and the purification procedures were simpler for the former. Furthermore, glass-ionomer cement samples made from the terpolymer prepared in sc-CO(2)/methanol exhibited higher CS and DTS and comparable BFS compared to the same polymer synthesized in water. The working properties of glass-ionomer formulations made in sc-CO(2)/methanol were comparable and better than the values of those for polymers synthesized in water. PMID:19269267

Moshaverinia, Alireza; Roohpour, Nima; Darr, Jawwad A; Rehman, Ihtesham U

2009-02-03

53

Reactivity of fluoride-containing calcium aluminosilicate glasses used in dental glass-ionomer cements.  

PubMed

The glass component critically determines the properties of glass-ionomer cements (GIC). However, the exact relationship between the composition of the glass and these properties is not yet fully understood. To investigate this relationship, we studied the reactivity of glasses used in commercial GIC in acetic acid solutions, using a pH-stat method. Qualitative differences in the leaching behavior of these glasses can be explained by different pre-treatments. Acid-washing and silanization modify the surfaces of the glass particles, thus inducing a delay of the leaching process, whereas untreated glasses exhibit a fast initial leaching, but their acid reactivity slows very soon. Quantitative differences in acid reactivity can be correlated with the mean chemical composition of the glasses. In this respect, the leaching tends to increase with an increasing ratio of network-dwelling cations to Al3+ ions. These results provide a fundamental basis for the explanation, prediction, and control of cement properties as a function of glass characteristics. PMID:9839789

De Maeyer, E A; Verbeeck, R M; Vercruysse, C W

1998-12-01

54

A review of glass-ionomers: From conventional glass-ionomer to bioactive glass-ionomer  

PubMed Central

Materials used in the body, especially the materials used in various oral cavity regions should be stable and passive without any interactions with the body tissues or fluids. Dental amalgam, composite resins and dental cements are the materials of choice with such properties. The first attempts to produce active materials, which could interact with the human body tissues and fluids were prompted by the concept that fluoride-releasing materials exert useful effects in the body. The concept of using the “smart” materials in dentistry has attracted a lot of attention in recent years. Conventional glass-ionomer (GI) cements have a large number of applications in dentistry. They are biocompatible with the dental pulp to some extent. GI is predominantly used as cements in dentistry; however, they have some disadvantages, the most important of which is lack of adequate strength and toughness. In an attempt to improve the mechanical properties of the conventional GI, resin-modified glass-ionomers have been marketed, with hydrophilic monomers, such as hydroxyethyl methacrylated (HEMA). Some recent studies have evaluated GI with bioactive glass in its structure to validate the claims that such a combination will improve tooth bioactivity, regeneration capacity and restoration. There is ever-increasing interest in the application of bioactive materials in the dental field in an attempt to remineralize affected dentin. The aim of this review article is to evaluate these materials and their characteristics and applications.

Khoroushi, Maryam; Keshani, Fateme

2013-01-01

55

Chlorhexidine-containing glass ionomer cement. A clinical investigation on the fissure caries inhibiting effect in first permanent molars.  

PubMed

Glass ionomer cement with addition of chlorhexidine used as a varnish on tooth surfaces has been shown to reduce the number of interproximal mutans streptococci (ms). The effect of a single application of such a varnish containing 2.5% chlorhexidine on occlusal caries development of the first permanent molars on 6-year-old children in a high caries incidence area was investigated. The children were examined according to WHO criteria and 262 children with 2 caries free contra-lateral molars were selected for treatment. Salivary ms samples were collected using the Strip-mutans (SM) method. After brushing the occlusal surfaces with a toothbrush and pumice in water slurry, rinsing and drying with a cotton roll, glass ionomer cement containing chlorhexidine (GI-CHX) and glass ionomer (GI) were applied randomly with a micro brush and the varnish was covered with occlusal wax. At baseline, the mean defs was 18.18 and DMFS was 0.25 and after one year 18.24 and 0.83 respectively. The salivary ms scores were high or very high (SM 2 and 3) in 85.6% at baseline. At the one-year follow up, the GI-CHX and GI materials could not be detected in the fissures. Also, a large number of fissure sealants had been placed in the molars outside the study protocol; thus 4% of the GI-CHX and GI, and 70% of the untreated were sealed at year one. Overall, there was no significant difference between the caries-reducing effect of GI-CHX and GI, but a trend towards a higher effect was seen for GI-CHX. Excluding the sealed molars the reduction was 74% in the GI-CHX-group, and 71% in the GI-group. Conclusion: Addition of 2.5% chlorhexidine to glass ionomer did not seem to increase the caries-reducing effect of the varnish in this high caries incidence population. PMID:16255352

Hoszek, Anders; Struzycka, Isabel; Jozefowicz, Agata; Wojcieszek, Danuta; Wierzbicka, Maria; Wretlind, Katarina; Ericson, Dan

2005-01-01

56

Bond strengths of two conventional glass-ionomer cements to irradiated and non-irradiated dentin.  

PubMed

This study evaluated the influence of irradiation on the dentin shear bond strength of two conventional glass ionomer cements (GICs). Thirty extracted molars were bisected in the mesio-distal direction. One-half of 20 teeth were irradiated with 60 Gy (5 days/week) for 6 weeks, and then GIC was placed on the irradiated dentin surface (Groups A1, B1). For the other halves of these tooth specimens, the GICs were first placed on their dentin surfaces and then the specimens irradiated (Groups A2, B2). The remaining 10 teeth were bisected and used as non-irradiated controls (Groups C1, C2). The GIC-dentin shear bond strengths were examined. Groups A2 and B2 had significantly lower bond strengths than groups A1, B1, C1, and C2 (p < 0.05). No significant differences were found among groups A1, B1, C1, and C2 (p > 0.05). In conclusion, irradiation may have an adverse effect on the bond strength of GICs depending on the application sequence. PMID:18972786

Yesilyurt, Cemal; Bulucu, Bilinç; Sezen, Orhan; Bulut, Güne?; Celik, Davut

2008-09-01

57

Antibacterial activity and physical properties of glass-ionomer cements containing antibiotics.  

PubMed

This study evaluated the antibacterial effects, physical properties and bonding strengths of conventional glass-ionomer cements (GICs) containing antibiotics and determined the optimal concentration of antibiotics addition for use with the ART approach. Fuji IX GIC was used as a control. Three antibiotic mixtures, ciprofloxacin, metronidazole and minocycline, were added to powdered GIC (Fuji IX) to obtain concentration ratios of 1.5, 3.0 and 4.5% w/w. The antibacterial activity of each GIC was evaluated against Streptococcus mutans or Lactobacillus casei using agar-diffusion methods. The release of antibiotics was analyzed by high-performance liquid chromatography (HPLC). The compressive strength and bonding strength to dentin were measured and compared with those of control samples. The results were analyzed using the Mann-Whitney test and Wilcoxon test. All tested groups showed a significantly greater inhibition with growth of the selected bacteria in comparison to the control groups (p < 0.01). However, the 3% and 4.5% concentration ratios of antibiotics had significantly lower compressive strength and lower bond strength to dentin than the control group (p = 0.003). The GIC-containing antibiotics were effective in inhibiting S Mutans and L Casei. The addition of a 1.5% antibiotic mixture was optimal to giving appropriate physical and bonding properties. PMID:19192833

Yesilyurt, Cemal; Er, Kursat; Tasdemir, Tamer; Buruk, Kurtulus; Celik, Davut

58

Use of glass ionomer cement containing antibiotics to seal off infected dentin: a randomized clinical trial.  

PubMed

Dental materials with antibacterial properties can prevent the harmful effects caused by oral cariogenic bacteria. This double-blind controlled clinical trial evaluated the performance of a glass ionomer cement (GIC) added with antibiotics for sealing infected dentin in atraumatic restorations of primary molars. The study enrolled 45 children (45 teeth) between 5 and 8 years of age, of both genders, divided into two groups: GC (n=22), where cavities were lined with a conventional GIC (Vidrion F) and GA (n=23), with cavities lined with Vidrion F added with 1% each of metronidazole, ciprofloxacin and cefaclor antibiotic. Both groups were restored with Ketac Molar Easymix. Molars with carious lesions on the inner half of dentin without clinical or radiographic pulp damage were selected. Patients were evaluated clinically (pain, fistulas or mobility) and radiographically (area of caries, periapical region and furcation) after 1, 3, 6 and 12 months. For statistical analysis, chi-squared or Fisher's exact tests were used with a 5% significance level. GA (82.6-95.7%) had better results than GC (12.5-36.4%) in all evaluations (p<0.05) and the difference in the success rate was 46.2-72.5% higher for GA. The use of the antibiotic-containing GIC liner on infected dentin proved satisfactory when applied in deciduous teeth. PMID:23657417

Ferreira, Jainara Maria Soares; Pinheiro, Sérgio Luiz; Sampaio, Fábio Correia; Menezes, Valdenice Aparecida de

2013-01-01

59

Effects of N-vinylpyrrolidone (NVP) containing polyelectrolytes on surface properties of conventional glass-ionomer cements (GIC).  

PubMed

It has been found that polyacids containing an N-vinylpyrrolidinone (NVP) comonomer produces a glass inomer cement with improved mechanical and handling properties. The objective of this study was to investigate the effect of NVP modified polyelectrolytes on the surface properties and shear bond strength to dentin of glass ionomer cements. Poly(acrylic acid (AA)-co-itaconic acid (IA)-co-N-vinylpyrrolidone) was synthesized by free radical polymerization. The terpolymer was characterized using (1)H NMR, FTIR spectroscopy and viscometry for solution properties. The synthesized polymers were used in glass ionomer cement formulations (Fuji II commercial GIC). Surface properties (wettability) of modified cements were studied by water contact angle measurements as a function of time. Work of adhesion values of different surfaces was also determined. The effect of NVP modified polyacid, on bond strength of glass-ionomer cement to dentin was also investigated. The mean data obtained from contact angle and bonding strength measurements were subjected to one- and two-way analysis of variance (ANOVA) at alpha=0.05. Results showed that NVP modified glass ionomer cements showed significantly lower contact angles (theta=47 degrees) and higher work of adhesion (WA=59.4 erg/cm(2)) in comparison to commercially available Fuji II GIC (theta=60 degrees and WA=50.3 erg/cm(2), respectively). The wettability of dentin surfaces conditioned with NVP containing terpolymer was higher (theta=21 degrees, WA=74.2 erg/cm(2)) than dentin conditioned with Fuji conditioner (theta=30 degrees, WA=69 erg/cm(2)). The experimental cement also showed higher but not statistically significant values for shear bond strength to dentin (7.8 MPa), when compared to control group (7.3 MPa). It was concluded that NVP containing polyelectrolytes are better dentin conditioners than the commercially available dentin conditioner (Fuji Cavity Conditioner, GC). NVP containing terpolymers can enhance the surface properties of GICs and also increase their bond strength to the dentin. PMID:19556000

Moshaverinia, Alireza; Roohpour, Nima; Ansari, Sahar; Moshaverinia, Maryam; Schricker, Scott; Darr, Jawwad A; Rehman, Ihtesham U

2009-06-24

60

Longevity of extensive class II open-sandwich restorations with a resin-modified glass-ionomer cement.  

PubMed

Several new techniques have been introduced for use in the esthetic restoration of posterior cavities to substitute for the presumed toxicity of amalgam. Composite-laminated glass-ionomer cement restorations, the sandwich technique, have been recommended for caries-risk patients. Clinical evaluation of the use of conventional glass-ionomer cements in the open-sandwich restoration has shown a high failure rate. The aim of this study was to evaluate the durability and cariostatic effect of a modified open-sandwich restoration utilizing a resin-modified glass-ionomer cement (RMGIC) in large cavities. The materials consisted of 274 mostly extensive Class II Vitremer/Z100 restorations performed by four dentists in 168 adults. Six experimental groups were investigated. In four groups a thick and in two groups a thin layer of cement was placed. Cavity conditioning before application of the RMGIC self-etching primer was done in 3 groups with polyacrylic acid and in one group with maleic acid; in two groups, only water rinsing was performed. The restorations were evaluated at baseline and after 6, 12, 24, and 36 months according to modified USPHS criteria (van Dijken, 1986). After 3 years, 239 restorations were evaluated. Twelve (5%) were estimated as non-acceptable. Two were replaced, and seven were repaired with resin composite. Tooth fractures were observed in 2.5%. Slight erosion of the RMGIC part was seen in 4%, and in one case operative treatment was indicated. Post-operative sensitivity was reported for 9 teeth. Forty-three percent of the patients were considered as caries-risk patients. Only one restoration showed secondary caries. The three-year results indicated that the modified open-sandwich restoration is an appropriate alternative to amalgam including extensive restorations. PMID:10403459

van Dijken, J W; Kieri, C; Carlén, M

1999-07-01

61

Ultrasonically set novel NVC-containing glass-ionomer cements for applications in restorative dentistry.  

PubMed

The objective of this study is to investigate the effects of application of ultrasound on the physical properties of a novel NVC (N-vinylcaprolactam)-containing conventional glass-ionomer cement (GIC). Experimental GIC (EXP) samples were made from the acrylic acid (AA)-itaconic acid (IA)-NVC synthesized terpolymer with Fuji IX powder in a 3.6:1 P/L ratio as recommended by the manufacturer. Specimens were mixed and fabricated at room temperature and were conditioned in distilled water at 37°C for 1 day up to 4 week. Ultrasound (US) was applied 20 s after mixing by placing the dental scaler tip on the top of the cement and applying light hand pressure to ensure the tip remained in contact with cement without causing any deformation. Vickers hardness was determined using a microhardness tester. The working and setting times were determined using a Gillmore needle. Water sorption was also investigated. Commercial Fuji IX was used as control for comparison (CON). The data obtained for the EXP GIC set through conventional set (CS) and ultrasonically set (US) were compared with the CON group, using one-way ANOVA and the Tukey multiple range test at ? = 0.05. Not only ultrasonic (US) application accelerated the curing process of both EXP cement and CON group but also improved the surface hardness of all the specimens. US set samples showed significantly lower water sorption values (P < 0.05) due to improved acid-base reaction within the GIC matrix and accelerated maturation process. According to the statistical analysis of data, significant increase was observed in the surface hardness properties of CS and US specimens both in EXP samples and the CON groups. It was concluded that it is possible to command set GICs by the application of ultrasound, leading to GICs with enhanced physical and handling properties. US application might be a potential way to broaden the clinical applications of conventional GICs in restorative dentistry for procedures such as class V cavity restorations. PMID:21769626

Moshaverinia, Alireza; Ansari, Sahar; Moshaverinia, Maryam; Schricker, Scott R; Chee, Winston W L

2011-07-19

62

Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing systems.  

PubMed

This study investigated the surface texture of two resin-modified glass ionomer cements (RMGICs) in the vertical and horizontal axis after treatment with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-flute tungsten carbide burs. The teeth were then randomly divided into four groups and finished/polished with (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Points (CS). The sample size for each material-finishing/polishing system combination was eight. The mean surface roughness (microm) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Mean RaV ranged from 0.59-1.31 and 0.83-1.52, while mean RaH ranged from 0.80-1.43 and 0.85-1.58 for Fuji II LC and Photac-Fil, respectively. Results of statistical analysis were as follows: Fuji II LC: RaV-RC, SS

Yap, Adrian U J; Tan, W S; Yeo, J C; Yap, W Y; Ong, S B

63

Clinical Performance of Viscous Glass Ionomer Cement in Posterior Cavities over Two Years  

PubMed Central

In this controlled prospective clinical study the highly viscous glass ionomer cement Ketac Molar was clinically assessed in Class I and Class II cavities. Forty-nine subjects (mean age 32.3 years) received 108 restorations placed by six operators in conventional Black I and II type cavities with undercuts after excavating primary lesions or after removing insufficient restorations. At baseline, and after 6, 12, and 24 months, restorations were assessed by two independent investigators according to modified USPHS codes and criteria. Impressions of the restorations were taken and epoxy replicas were made. Between the baseline and the 24-month recall, 51 representative samples were analyzed at 130 × magnification by use of a stereo light microscope (SLM). Recall rates were 83% after 6 months, 50% after 12 months, and 24% after 24 months. Failure rates after 24 months were 8% for Class I and 40% for Class II fillings, mainly due to bulk fracture at occlusally loaded areas (Kaplan Meier survival analysis). Significant changes over time were found for the criteria “surface roughness”, “marginal integrity”, “restoration integrity”, and “overall judgement” (P < .05; Friedman test). SLM analysis revealed statistically significant differences for the following criteria over time (baseline/6 months/12 months (in % of entire evaluable margin length); P < .05; Friedman 2-way ANOVA): perfect margin 37/19/11, negative step formation 26/49/57, gap formation 2/7/9, and overhang 24/11/8. Replicas exhibited mainly negative step formation as main finding due to apparently inferior wear resistance (P < .05). Gap formations were more frequently observed in Class II restorations than in Class I (12% versus 3% after 12 months; P < .05, Mann-Whitney-U test). The evaluated margin lengths were not statistically different (P > .05, Friedman 2-way ANOVA).

Frankenberger, Roland; Garcia-Godoy, Franklin; Kramer, Norbert

2009-01-01

64

Influence of acid washing on the surface morphology of ionomer glasses and handling properties of glass ionomer cements.  

PubMed

Acid washing is known to influence the handling properties of ionomer glasses used in glass ionomer cements due to the production of an ion depleted-zone on the surface of the glass particles. The influence of acid washing on the particle size distribution and surface area of four glasses was examined by scanning electron microscopy (SEM), particle size analysis (PSA) and accelerated surface area porosimetry (ASAP) and the working and setting times of cements, produced from the glasses, correlated to changes in surface morphology. A linear relationship was found between the specific surface area of acid-washed SiO(2)-Al(2)O(3)-XF(2)-P(2)O(5) glasses (X being either calcium or strontium) and their cement working and setting times. These changes directly correlated with increases in the mesopore volume. However, the influence of acid washing on the surface morphology was also found to be glass composition-dependent with the addition of sodium into the glass network resulting in no significant change in the surface area or mesopore volume despite changes in the working and setting time. Through examination of the influence of acid washing and glass composition on the specific surface area improvements in the control of the working and setting times of glass ionomer cements may be achieved. PMID:17387590

Crowley, C M; Doyle, J; Towler, M R; Rushe, N; Hampshire, S

2007-03-27

65

A 2-year clinical study of two glass ionomer cements used in the atraumatic restorative treatment (ART) technique.  

PubMed

The purpose of the study was to evaluate, in a clinical study over 2 years, the deterioration of two glass ionomer cements used with the atraumatic restorative treatment (ART) technique or approach. Fifty-five Fuji IX and 45 ChemFil Superior restorations were placed randomly in 23 adult patients, mainly in small occlusal preparations in molar teeth. The restorations were placed in a dental hospital by one dentist using the ART technique. Photographs, radiographs and replicas were obtained at baseline and subsequent recalls. Both cements were easy to mix and place, but the radiolucency of ChemFil Superior was a disadvantage. Both cements also showed early high losses of sealant and restorative material. After 2 years, 34.5% of the sealants appeared to be completely lost, with caries recorded in 5.3% of the exposed fissures. In some instances, these small lesions may have been present, but not detected clinically, at the time of sealing. Restoration failures of 7.0% were from wear and fracture of the cements and recurrent caries. Mean cumulative wear was 83.1 microm for Fuji IX and 104.0 microm for ChemFil Superior, which was not statistically significant. The cements became darker after their placement to more closely match the restored teeth, but there were few exact matches. There was no surface staining and only minor marginal discrepancies and staining associated with the restorations. Although the short-term clinical performance of the two glass ionomer cements was reasonable, the materials require further improvements in their mechanical properties, to reduce sealant losses and wear. The cements evaluated appear suitable for restricted use only, in posterior teeth. PMID:10385357

Ho, T F; Smales, R J; Fang, D T

1999-06-01

66

Degree of conversion and hardness of two different systems of the Vitrebond™ glass ionomer cement light cured with blue LED.  

PubMed

This study investigated the physicochemical properties of the new formulation of the glass ionomer cements through hardness test and degree of conversion by infrared spectroscopy (FTIR). Forty specimens (n = 40) were made in a metallic mold (4 mm diameter x 2 mm thickness) with two resin-modified glass ionomer cements, Vitrebond™ and Vitrebond™ Plus (3M/ ESPE). Each specimen was light cured with blue LED with power density of 500 mW/cm(2) during 30 s. Immediately after light curing, 24h, 48h and 7 days the hardness and degree of conversion was determined. The Vickers hardness was performed by the MMT-3 microhardness tester using load of 50 gm force for 30 seconds. For degree of conversion, the specimens were pulverized, pressed with KBr and analyzed with FT-IR (Nexus 470). The statistical analysis of the data by ANOVA showed that the Vitrebond™ and Vitrebond™ Plus were no difference significant between the same storage times (p > 0.05). For degree of conversion, the Vitrebond™ and Vitrebond™ Plus were statistically different in all storage times after light curing. The Vitrebond™ showed higher values than Vitrebond™ Plus (p < 0.05). The performance of Vitrebond™ had greater results for degree of conversion than Vitrebond™ Plus. The correlation between hardness and degree of conversion was no evidence in this study. PMID:23811653

Calixto, Luiz Rafael; Tonetto, Mateus Rodrigues; Pinto, Shelon Cristina Souza; Barros, Erico Damasceno; Borges, Alvaro Henrique; Lima, Fabricio Viana Pereira; de Andrade, Marcelo Ferrarezi; Bandéca, Matheus Coelho

2013-03-01

67

Surface finish of resin-modified and highly viscous glass ionomer cements produced by new one-step systems.  

PubMed

This study investigated the surface finish of resin-modified (Fuji II LC, GC) and highly viscous (Fuji IX GP Fast, GC) glass ionomer cements after treatment with three one-step finishing/polishing systems (One-Gloss [OG], Shofu; Pogo [PG], Dentsply; Sof-Lex Brush [SB], 3M-ESPE). The surface roughness obtained was compared to that using a matrix strip [MS], a two-step rubber abrasive (CompoSite [CS], Shofu) and a graded abrasive disk (Super Snap [SS], Shofu) system. Eight specimens (3-mm long x 3-mm wide x 2-mm deep) of each material were made for the various treatment groups. With the exception of the MS group, all groups were roughened with 320 grit grinding paper using a lapping device prior to finishing/polishing with the different systems. The mean surface roughness (microm) was measured with a profilometer. Data was subjected to ANOVA/Scheffe's tests at significance level 0.05. Mean Ra ranged from 0.13 to 1.04 microm for Fuji II LC and 0.14 to 0.81 for Fuji IX GP. For both materials, the smoothest surface was obtained with MS and the roughest with OG. Depending on the materials, the surface finish produced by PG and SB was superior or comparable to that obtained with CS and SS. The effectiveness of one-step systems, when used to finish/polish resin-modified and highly viscous glass ionomer cements, is product dependent. PMID:14753338

Yap, Adrian U J; Ng, J J; Yap, S H; Teo, C K

68

Kinetics of fluoride ion release from dental restorative glass ionomer cements: the influence of ultrasound, radiant heat and glass composition.  

PubMed

To compare the effect of ultrasonic setting with self curing on fluoride release from conventional and experimental dental glass ionomer cements. To compare hand mixed and capsule mixing and the effect of replacing some of the reactive glass with zirconia. In a novel material which advocated using radiant heat to cure it, to compare the effect of this with ultrasound. To evaluate the effect of ultrasound on a glass ionomer with fluoride in the water but not in the glass. 10 samples of each cement were ultrasonically set for 55 s; 10 controls self cured for 6 min. Each was placed in 10 ml of deionised water which was changed at 1, 3, 7, 14, 21, 28 days. The solution fluoride content was measured using a selective ion electrode. All ultrasound samples released more fluoride than the controls. Release patterns were similar; after a few days, cumulative fluoride was linear with respect to t(1/2). Slope and intercept of linear regression plots increased with ultrasound. With radiant heat the cement released less fluoride than controls. The effect of ultrasound on cement with F in water increased only slope not intercept. Zirconia addition enhances fluoride release although the cement fluorine content is reduced. Comparison of capsule and hand mixing showed no consistent effect on fluoride release. Ultrasound enhances fluoride release from GICs. As heat has an opposite effect the heat from ultrasound is not its only action. The lesser effect on cement with fluoride only in the water indicates that of ultrasound enhances fluoride release from glass. PMID:19851843

Thanjal, N K; Billington, R W; Shahid, S; Luo, J; Hill, R G; Pearson, G J

2009-10-23

69

Reactions in glass ionomer cements: V. Effect of incorporating tartaric acid in the cement liquid.  

PubMed

A description is give of the effect on the ASPA cement reaction of tartaric acid incorporated in the cement liquid. Tartaric acid acts as an accelerator that aids in the extraction of ions from the aluminosilicate glass and facilitates their binding to the polyanion chains. Postgelation hardening is significantly increased. Working time is unaffected possibly because cations are initially present as complexes. PMID:187629

Crisp, S; Wilson, A D

70

Bond strength of resin-reinforced glass ionomer cements after enamel etching.  

PubMed

This study evaluated the shear bond strength of resin-reinforced glass ionomers to enamel etched or unetched. Human, non-carious extracted permanent molars stored in distilled water were used. Flat buccal and lingual enamel surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into six groups of 5 teeth (10 surfaces) each: Group 1: Fuji II LC, no enamel etching; Group 2: Fuji II LC, enamel etched with 10% phosphoric acid for 10 seconds; Group 3: Dyract, no enamel etching; Group 4: Dyract, enamel etched with 10% phosphoric acid for 10 seconds; Group 5: Photac-Fil, no enamel etching; Group 6: Photac-Fil, enamel etched with 10% phosphoric acid for 10 seconds. Cylindrical samples of the glass ionomers were prepared in plastic molds and bonded to the enamel surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hours, and sheared with an Instron at a crosshead speed of 0.5 mm/minute. The results (in MPa) were: Group 1: 11.29 +/- 4.84; Group 2: 19.64 +/- 5.43; Group 3: 8.26 +/- 3.61; Group 4: 22.04 +/- 5.40; Group 5: 2.05 +/- 3.05; Group 6: 9.12 +/- 6.61. ANOVA and Student-Newman-Keuls procedure revealed that on etched enamel, Fuji II LC and Dyract had a significantly higher bond strength than all the other groups tested (P < 0.0001), but not significantly different between each other. With these two groups, cohesive failure within the material was recorded in all samples while in the unetched samples, all specimens displayed an adhesive failure (glass ionomer-enamel interface). All samples with Photac-Fil, with or without enamel etching had adhesive failures. PMID:7880480

Cortes, O; Garcia-Godoy, F; Boj, J R

1993-12-01

71

The use of laser-induced breakdown spectroscopy for the determination of fluorine concentration in glass ionomer cement  

NASA Astrophysics Data System (ADS)

The influence of He atmosphere and gate width in laser-induced breakdown spectroscopy (LIBS) determination of fluorine concentration was investigated in detail. The measurements were realized on two double pulse LIBS devices featuring different parameters. Calibration curves, describing the relationship between the fluorine concentration and the corresponding intensity of the LIBS signal, were constructed for both LIBS devices, with and without He flow, respectively. Detection limits achieved were in the range 1.18-0.47 wt.%. The best LOD value was obtained in He atmosphere. The LIBS measurement of fluorine content is influenced by different gate widths and the atmosphere in the working chamber. The proposed method was successfully applied to the determination of fluorine concentration in glass ionomer cements.

Kratochvíl, T.; Pouzar, M.; Novotný, K.; Havránek, V.; ?ernohorský, T.; Zvolská, M.

2013-10-01

72

Fracture patterns of glass-ionomer cement overlays versus stainless steel bands during endodontic treatment: an ex-vivo study.  

PubMed

AIM: To compare fracture patterns of posterior teeth temporized with: mesio-occlusal-distal (MOD) glass-ionomer cement (GIC) interim restorations, stainless steel (SS) bands, GIC dome overlays and GIC dome overlays with occlusal temporary restorations. METHODOLOGY: The root canals of 92 extracted human premolars and molars were prepared with rotary NiTi instruments and dressed with calcium hydroxide paste prior to cavity preparation for standardized MOD restorations. Teeth were divided into four groups (n = 23) and temporarily restored with: GIC interim restorations (GIC group), stainless steel bands (SS group), GIC dome overlays (GIC-O group) or GIC dome overlays with intermediate restorative material (IRM) in the access cavities (GIC-IRM group). Teeth were subjected to compressive axial load until fracture; fracture forces and fracture modes were recorded. Statistical analysis included Kaplan-Meier plots, Cox proportional hazards model, one-way analysis of variance, chi-square and Fisher's exact tests. RESULTS: There was a significantly higher risk of failure in the GIC group compared with the SS (P < 0.001), GIC-O (P < 0.001) and GIC-IRM (P = 0.001) groups. The mean fracture force for SS was significantly higher than GIC-O (P = 0.03) and GIC-IRM (P < 0.001). GIC fracture force was significantly lower than all other groups (P < 0.001). Significantly fewer unfavourable fractures were observed in SS compared with GIC (P = 0.001), GIC-O (P = 0.007) and GIC-IRM (P < 0.001). CONCLUSIONS: Glass-ionomer cement dome overlays with reduced cuspal height and occlusal inclines may be recommended for broken-down posterior teeth, without any risk of poor aesthetics, gingival irritation or further proximal tooth structure loss. Stainless steel bands may only need to be used in extensively broken-down teeth or in the presence of parafunctional habits. PMID:23550590

Pakdeethai, S; Abuzar, M; Parashos, P

2013-03-14

73

Efficiency of glass ionomer cement linings in preventing microleakage under Class V composite resin restorations.  

PubMed

The ability of glass ionomer linings to aid in the prevention of microleakage under Class V composite resin restorations has been investigated. A conventional glass ionomer lining (Ketac-bond) and two light cured linings (Vitrabond and Timeline) were evaluated with respect to their ability to reduce microleakage. Seventy two Class V cavities were restored either by a bulk fill or incremental fill technique, and following restoration, half the teeth were thermocycled in artificial saliva. Dye penetration, using a Procion orange dye was recorded along the gingival dentine wall and at the occlusal enamel margin for all teeth. The results showed significant differences in leakage along the gingival dentine wall between the various linings under all conditions. Vitrabond produced significantly less leakage than Ketac bond which in turn produced significantly less leakage than Timeline. Significant differences in microleakage were noted between the thermocycled and non-thermocycled groups. Little or no significant differences in leakage were shown between the bulk filled and incremental filled teeth. PMID:2096890

Meyers, I A

1990-01-01

74

Short-term evaluation of the pulpo-dentin complex response to a resin-modified glass-ionomer cement and a bonding agent applied in deep cavities  

Microsoft Academic Search

Objectives. To evaluate the response of the pulpo-dentin complex following application of a resin-modified glass-ionomer cement or an adhesive system in deep cavities performed in human teeth.Methods. Deep class V cavities were prepared on the buccal surface of 26 premolars. In Group 1 the cavity walls (dentin) and enamel were conditioned with 32% phosphoric acid and the dentin adhesive system

Carlos Alberto de Souza Costa; Elisa Maria Aparecida Giro; Alexandre Batista Lopes do Nascimento; Hilcia Mezzalira Teixeira; Josimeri Hebling

2003-01-01

75

Comparative evaluation of effect of polymerizable and non-polymerizable desensitizing agents on crown-retentive-strength of zinc-phosphate, glass-ionomer and compomer cements.  

PubMed

The Purpose of this study was to evaluate the effect of polymerizable and non-polymerizable dentine desensitizers on retention of complete cast crowns cemented with three different types of cements. Freshly extracted human molars (n = 90) were prepared for standardized crown preparation (6-degree taper 4-mm height). The axial surface area of each preparation was determined and specimens were distributed equally among groups (n = 10). Dentine desensitizers, cementing agents, glass ionomer cement and compomer cement. Teeth were prepared and individual castings were made using high noble porcelain-metal alloy. Castings were cemented, thermo-cycled and removed along the path of insertion using a universal testing machine. Tooth surface as well as inner surface of the casting was examined and nature of cement failure was determined. Compomer cement exhibited the highest retentive strength and all dentine treatments resulted in significantly different retentive values. Zinc phosphate was the least retentive. Crown retentive values of Compomer cement were improved with Prime & Bond NT and Gluma Desensitizer Retentive values of zinc phosphate cement with Prime & Bond NT were decreased and not affected with Gluma Desensitizer Retentive values of Glass ionomer cement were not affected by any of the desensitizers used in the study. PMID:23101176

Patil, P G; Parkhedkar, R D; Patil, S P; Bhowmik, H S

2012-09-01

76

[Study on disintegration of glass ionomer cements. Effect of the starting time of immersion on the dissolution of Ca, Al and Si].  

PubMed

The disintegration of glass ionomer cements was evaluated with referred to the amounts of component elements of powders dissolved into solutions at various starting times of immersion. Glass ionomer cement products, three for luting and three for filling, were used. The starting times of immersion in solutions were; setting time and 10, 30 and 60 minutes and 24 hours after start of mixing. After the immersion in 30 ml of distilled water and physiological saline solution for 1 week, these solutions were analyzed by an atomic absorption spectrophotometer to determine the amounts of Ca, Al and Si. The amount of each element dissolved was highest when immersion in the solutions was started at the setting time except for Ca dissolved in physiological saline solution, and it tended to decrease as the start of immersion in the solutions was delayed. Some products contained Sr instead of Ca. The results indicated that glass ionomer cement should be protected from exposure to oral fluids for about 30 minutes in clinical use. PMID:2135529

Nomata, H

1990-05-01

77

Microleakage at gingival dentin margins of Class V composite restorations lined with light-cured glass ionomer cement.  

PubMed

This study compared the microleakage of light-cured and auto-set glass ionomer liners used in Class V composite laminated glass ionomer restorations by determining the amount of microleakage at the gingival cementum/dentin margins. Standardized nonundercut V-shaped Class V cavities with gingival margins below the cementoenamel junction were prepared on the mesial and distal surfaces of 40 molars, establishing a total of 80 cavities, which were randomly divided into four groups. Each was lined with glass ionomers: group 1, Ketac-Bond (ESPE-Premier), which served as the control; group 2, XR-Ionomer (Kerr); group 3, XR-Ionomer with polyacrylic acid (PAA) pretreatment (Kerr); and group 4, Vitrabond (3M). Specimens were thermocycled for 300 cycles in 0.5% aqueous solution of basic fuchsin between 4 and 55 C with a 1-minute dwell time, and individually embedded in an epoxy resin. Statistical analysis indicated no differences among groups using the light-cured glass ionomer (groups 2 to 4), and they showed significantly less leakage than the control (group 1) at P less than 0.00001). Removal of the smear layer using 10% polyacrylic acid solution did not influence microleakage in restorations with light-cured glass ionomer liners. PMID:2277155

Tjan, A H; Dunn, J R

1990-12-01

78

Evaluating acrylic and glass-ionomer cement strength using the biaxial flexure test  

Microsoft Academic Search

Frequently, bone cement strengths are evaluated from uniaxial tests, such as three- or four-point flexure. Measurement of material strength in this manner may not provide an accurate characterisation of a bone cements true load-bearing capacity. In most orthopaedic applications, there exists a state of biaxial stress and so biaxial strength information is most useful. To address this issue, the biaxial

W. A. J. Higgs; P. Lucksanasombool; R. J. E. D. Higgs; M. V. Swain

2001-01-01

79

Absence of carious lesions at margins of glass-ionomer cement and amalgam restorations: An update of systematic review evidence  

PubMed Central

Background This article aims to update the existing systematic review evidence elicited by Mickenautsch et al. up to 18 January 2008 (published in the European Journal of Paediatric Dentistry in 2009) and addressing the review question of whether, in the same dentition and same cavity class, glass-ionomer cement (GIC) restored cavities show less recurrent carious lesions on cavity margins than cavities restored with amalgam. Methods The systematic literature search was extended beyond the original search date and a further hand-search and reference check was done. The quality of accepted trials was assessed, using updated quality criteria, and the risk of bias was investigated in more depth than previously reported. In addition, the focus of quantitative synthesis was shifted to single datasets extracted from the accepted trials. Results The database search (up to 10 August 2010) identified 1 new trial, in addition to the 9 included in the original systematic review, and 11 further trials were included after a hand-search and reference check. Of these 21 trials, 11 were excluded and 10 were accepted for data extraction and quality assessment. Thirteen dichotomous datasets of primary outcomes and 4 datasets with secondary outcomes were extracted. Meta-analysis and cumulative meta-analysis were used in combining clinically homogenous datasets. The overall results of the computed datasets suggest that GIC has a higher caries-preventive effect than amalgam for restorations in permanent teeth. No difference was found for restorations in the primary dentition. Conclusion This outcome is in agreement with the conclusions of the original systematic review. Although the findings of the trials identified in this update may be considered to be less affected by attrition- and publication bias, their risk of selection- and detection/performance bias is high. Thus, verification of the currently available results requires further high-quality randomised control trials.

2011-01-01

80

Microleakage after Thermocycling of Three Self-Etch Adhesives under Resin-Modified Glass-Ionomer Cement Restorations.  

PubMed

This study was designed to evaluate microleakage that appeared on Resin-Modified Glass-Ionomer Cement (RMGIC) restorations. Sixty class V cavities (h x w x l = 2 mm x 2 mm x 3 mm) were cut on thirty extracted third molars, which were randomly allocated to three experimental groups. All the buccal cavities were pretreated with polyacrylic acid, whereas the lingual cavities were treated with three one-step Self-Etch adhesives, respectively, Xeno III (Dentsply Detrey GmbH, Konstanz, Germany), iBond exp (Heraeus Kulzer gmbH & Co. KG, Hanau, Germany), and Adper Prompt-L-Pop (3M ESPE AG, Dental products Seefeld, Germany). All cavities were completely filled with RMGIC, teeth were thermocycled for 800 cycles, and leakage was evaluated. Results were expressed as means +/- standard deviations (SDs). Microleakage scores were analysed by means of generalized linear mixed models (GLMMs) assuming an ordinal logistic link function. All results were considered to be significant at the 5% critical level (P < .05). The results showed that bonding RMGIC to dentin with a Self-Etch adhesive rather than using polyacrylic acid did not influence microleakage scores (P = .091), except for one tested Self-Etch adhesive, namely, Xeno III (P < .0001). Nevertheless, our results did not show any significant difference between the three tested Self-Etch adhesive systems. In conclusion, the pretreatment of dentin with Self-Etch adhesive system, before RMGIC filling, seems to be an alternative to the conventional Dentin Conditioner for the clinicians as suggested by our results (thermocycling) and others (microtensile tests). PMID:20628510

Geerts, Sabine O; Seidel, Laurence; Albert, Adelin I; Gueders, Audrey M

2010-06-06

81

Microleakage after Thermocycling of Three Self-Etch Adhesives under Resin-Modified Glass-Ionomer Cement Restorations  

PubMed Central

This study was designed to evaluate microleakage that appeared on Resin-Modified Glass-Ionomer Cement (RMGIC) restorations. Sixty class V cavities (h × w × l = 2?mm × 2?mm × 3?mm) were cut on thirty extracted third molars, which were randomly allocated to three experimental groups. All the buccal cavities were pretreated with polyacrylic acid, whereas the lingual cavities were treated with three one-step Self-Etch adhesives, respectively, Xeno III (Dentsply Detrey GmbH, Konstanz, Germany), iBond exp (Heraeus Kulzer gmbH & Co. KG, Hanau, Germany), and Adper Prompt-L-Pop (3M ESPE AG, Dental products Seefeld, Germany). All cavities were completely filled with RMGIC, teeth were thermocycled for 800 cycles, and leakage was evaluated. Results were expressed as means ± standard deviations (SDs). Microleakage scores were analysed by means of generalized linear mixed models (GLMMs) assuming an ordinal logistic link function. All results were considered to be significant at the 5% critical level (P < .05). The results showed that bonding RMGIC to dentin with a Self-Etch adhesive rather than using polyacrylic acid did not influence microleakage scores (P = .091), except for one tested Self-Etch adhesive, namely, Xeno III (P < .0001). Nevertheless, our results did not show any significant difference between the three tested Self-Etch adhesive systems. In conclusion, the pretreatment of dentin with Self-Etch adhesive system, before RMGIC filling, seems to be an alternative to the conventional Dentin Conditioner for the clinicians as suggested by our results (thermocycling) and others (microtensile tests).

Geerts, Sabine O.; Seidel, Laurence; Albert, Adelin I.; Gueders, Audrey M.

2010-01-01

82

A preliminary report on the effect of storage in water on the properties of commercial light-cured glass-ionomer cements.  

PubMed

Two commercially available light-curable glass-ionomer cements, Vitrebond and XR-Ionomer, have been studied and their compressive strengths measured following storage under wet and dry conditions for varying lengths of time up to 3 months. The strongest cements were those stored in air and allowed to age. On the other hand, cements that were stored in water were found to become progressively weaker with time. Their failure mode was different from that of cements stored in air in that specimens became barrel-shaped as they were loaded and exhibited considerable plastic deformation prior to fracturing. By contrast, air-stored specimens behaved as predominantly brittle materials, the specimens essentially maintaining their integrity up to the point of catastrophic failure. Both of these findings indicate that the properties of these particular light-cured cements change markedly on exposure to moisture, a fact which is of clinical significance. PMID:1503849

Nicholson, J W; Anstice, H M; McLean, J W

83

Glass ionomer cement formulations: I. The preparation of novel fluoroaluminosilicate glasses high in fluorine.  

PubMed

The preparation of a large number of novel fluorine-containing aluminosilicate glasses is reported along with the properties of cements formed by their reaction to aqueous solutions of poly- (acrylic acid) (PAA). PMID:286706

Kent, B E; Lewis, B G; Wilson, A D

1979-06-01

84

Glass-ionomer Cement Formulations. II. The Synthesis of Novel Polycarboxylic Acids  

Microsoft Academic Search

The synthesis of many polycarboxylic acids is reported. An account is given of their stability in aqueous solution and the properties of cements formed by their reaction with ion-leachable glasses. A copolymer of acrylic and itaconic acids was found to combine several favorable characteristics.

Stephen Crisp; Brian E. Kent; Brian G. Lewis; Alan J. Ferner; Alan D. Wilson

1980-01-01

85

A preliminary clinical trial using flowable glass-ionomer cement as a liner in proximal-ART restorations: The operator effect  

PubMed Central

Objectives: This in vivo study was carried out to assess the influence of the operator experience on the survival rate of proximal-ART restorations using a two-layer technique to insert the glass-ionomer cement (GIC). Study Design: Forty five proximal cavities in primary molars were restored in a school setting according to the ART technique. The cavities were restored by two operators with Ketac Molar Easymix, and received a flowable layer of GIC prior to a second GIC layer with a regular consistency. The operators had different clinical experiences with ART (no experience or two years of experience), but both completed a one-week training to perform the restorations and the GIC mixing in this study. Results: After a 12-month follow-up, 74% of the restorations survived; the main reason for failure was bulk fracture or total loss of the restoration.There was no operator influence (log-rank test p=0.2) Conclusion: The results encourage future well designed controlled clinical trials using the two-layer technique for insertion of GIC in proximal-ART restorations, after training the operators. Key words:Atraumatic Restorative Treatment (ART), Glass-ionomer, proximal restorations.

Hesse, Daniela; Bonecker, Marcelo; Van Loveren, Cor; Van Amerongen, W E.; Raggio, Daniela P.

2013-01-01

86

Synthesis and characterization of a novel N-vinylcaprolactam-containing acrylic acid terpolymer for applications in glass-ionomer dental cements.  

PubMed

In this study a novel N-vinylcaprolactam (NVC)-containing copolymer of acrylic-itaconic acid was synthesized, characterized and incorporated into Fuji IX conventional glass-ionomer cement (GIC). Subsequently, the effects of incorporation of synthesized terpolymer on the mechanical properties of GIC were studied. The synthesized terpolymer was characterized using (1)H nuclear magnetic resonance, Fourier transform infrared and Raman spectroscopy. The viscosity and molecular weight of the terpolymer were also measured. The compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS) of the modified GICs were evaluated after 24h and 1week of immersion in distilled water at 37 degrees C. The handling properties (working and setting times) of the resulting modified cements were also evaluated. One-way analysis of variance was used to study the statistical significance of the mechanical strengths and handling properties in comparison to the control group. The results showed that NVC-containing GIC samples exhibited significantly higher (P<0.05) DTS (38.3+/-10.9MPa) and BFS (82.2+/-12.8MPa) in comparison to Fuji IX GIC (DTS=19.6+/-11.4MPa; BFS=41.3+/-10.5MPa). The experimental cement also showed higher but not statistically significant values for CS compared to the control material (CS for NVC-containing sample=303+/-32.8MPa; CS for Fuji XI=236+/-41.5MPa). Novel NVC-containing GIC has been developed in this study, with a 28% increase in CS. The presented GIC is capable of doubling the DTS and BFS in comparison to commercial Fuji IX GIC. The working properties of NVC-containing glass-ionomer formulations are comparable and are acceptable for water-based cements. PMID:19289308

Moshaverinia, Alireza; Roohpour, Nima; Darr, Jawwad A; Rehman, Ihtesham U

2009-02-20

87

Radiopacity of resin-modified glass ionomer liners and 2 bases  

Microsoft Academic Search

Statement of problem. Lining and base materials for restorations have traditionally been autopolymerized and include conventional glass ionomer cements. Light-cured resin-modified glass ionomer cements have recently become available, but a lack of information exists regarding their radiopacity.Purpose of study. In this study the radiopacity of glass ionomer cements was assessed with a standard method that related densitometric measurements to an

P. M. M. Shah; S. K. Sidhu; B. S. Chong; T. R. Pitt Ford

1997-01-01

88

The effect of glass ionomer cement Fuji IX on the hard tissues of teeth treated by sparing methods (ART and CMCR)  

Microsoft Academic Search

Purpose: The aim of the study was to assess the effect of glass ionomer fillings Fuji IX on the mineral content of the hard dental tissues of carious teeth treated by sparing methods. Material and methods: The study material consisted of 4 deciduous teeth lost due to physiological resorption. The teeth had glass ionomer fillings Fuji IX inserted after treatment

Marczuk-Kolada G; Waszkiel D; Kierklo A; Mystkowska J

2006-01-01

89

Effect of fluorosis on shear bond strength of glass ionomer–based restorative materials to dentin  

Microsoft Academic Search

Statement of problem. Several studies have investigated the adhesion of glass ionomer-based restorative materials to nonfluorotic teeth, but there appears to be no information on the bond strength of these restorative materials to dentin in fluorotic teeth. Purpose. This study investigated the effect of dental fluorosis on the bond strength of Ketac-fil conventional glass ionomer cement, Vitremer resin-modified glass ionomer

Wedad Y. Awliya; E. S. Akpata

1999-01-01

90

In vivo bracket retention comparison of a resin-modified glass ionomer cement and a resin-based bracket adhesive system after a year  

Microsoft Academic Search

Glass ionomer orthodontic adhesives cause less enamel demineralization during fixed orthodontic appliance treatment than do traditional resin-based products. An in vivo randomized clinical trial was performed comparing the clinical performance of a resin-modified glass ionomer (RMGI) adhesive with a no-mix, resin-based (the control) adhesive over a 12-month period. The split-mouth technique was used to analyze bracket retention, bracket failure causes,

David J. Hegarty; Tatiana V. Macfarlane

2002-01-01

91

Long-term mechanical characteristics of resin-modified glass ionomer restorative materials  

Microsoft Academic Search

Objectives. The purpose of this study was to compare the effects of long-term water storage on the mechanical characteristics of four resinmodified glass ionomer restorative materials with those of a conventional glass ionomer cement and a resin composite material.Methods. Cylindrical specimens were prepared and stored in water for 1 h, 24 h, 1 wk, 1 mon, 3 mon and 6

Shigeru Uno; Werner J. Finger; Ulrike Fritz

1996-01-01

92

Comparison of two minimally invasive methods on the longevity of glass ionomer cement restorations: short-term results of a pilot study.  

PubMed

The purpose of this study was to evaluate the clinical performance of glass ionomer cement (GIC) restorations comparing two minimally invasive methods in permanent teeth after 12 months. Fifty pregnant women (second trimester of pregnancy), mean age 22 +/- 5.30 years, were treated by two previously trained operators. The treatment approaches tested were: chemomechanical method (Carisolv; MediTeam) and atraumatic restorative treatment (ART). A split-mouth study design was used in which the two treatments were randomly placed in 50 matched pairs of permanent teeth. The chemomechanical method (CM) was the test group and the ART was the control group. The treatments were performed in Public Health Centers. The tested restorative material was a high-strength GIC (Ketac Molar; 3M/ESPE). The restorations were placed according to the ART guidelines. Two calibrated independent examiners evaluated the restorations in accordance with ART criteria. The inter-examiner kappa was 0.97. Data were analyzed using 95% confidence interval on the binomial distribution and Fisher's exact test at 5% significance level. In a 12-month follow-up, 86% of the restorations were evaluated. In the test group (CM), 100% (CI=93.3-100%) of the restorations were considered successful. In the control group (ART) 97.6% (CI=87.4-99.9%) of the restorations were considered successful and 2.4% unsuccessful (marginal defect >0.5 mm). There was no statistically significant difference between the 12-month success rate for both groups (Fisher's exact test: P=0.49) and between the two operators (Fisher's exact test: P=1.00). Both minimally invasive methods, chemomechanical method and ART, showed a similar clinical performance after 12 months of follow up. PMID:19089209

Barata, Terezinha Jesus Esteves; Bresciani, Eduardo; Mattos, Maria Cecília Ribeiro; Lauris, José Roberto Pereira; Ericson, Dan; Navarro, Maria Fidela de Lima

93

Reactivity ofFluoride-contain ing Calcium Aluminosilicate Glasses Used inDental Glass-ionomer Cements  

Microsoft Academic Search

Theglass component critically determines the properties ofglass-ionomer cements (GIC). However, the exact relationship between thecomposition oftheglass and these properties isnotyetfully understood. Toinvestigate this relationship, westudied thereactivity ofglasses usedin commercial GICinacetic acidsolutions, usingapH-stat method. Qualitative differences intheleaching behavior of these glasses canbeexplained bydifferent pre-treatments. Acid-washing andsilanization modifythesurfaces ofthe glass particles, thusinducing adelayoftheleaching process, whereas untreated glasses exhibit afast initial leaching, buttheir

E. A. P. DeMaeyerl; R. M. H. Verbeeck; W. J. Vercruysse

94

A comparative study of the bond strengths of amalgam and alloy-glass ionomer cores.  

PubMed

The purpose of this study was to compare the bond strengths of dental amalgam cores and dental alloy-glass ionomer cores that were luted to cast gold crowns with glass ionomer cement. Seventy-two human extracted molars were sectioned horizontally and four regular thread mate system pins were inserted into a flat pulpal floor. The teeth were restored with amalgam or alloy-glass ionomer admixture and prepared for crown preparations. Castings were produced with type III gold and cemented to the cores with Fuji type I glass ionomer cement. Thirty-six of the specimens were subjected to thermal fatigue by cycling between 4 and 50 degrees C for periods of 1, 5 and 10 weeks. The remainder of the specimens were retained in deionized water at 37 degrees C. Bond strengths of the cores, in tension, were measured with a universal testing machine. The alloy-glass ionomer cores exhibited higher bond strengths than the amalgam cores for virtually all time periods, particularly the thermocycled samples. The alloy-glass ionomer cores exclusively displayed core fractures and pin/tooth insufficiencies while the amalgam cores failed because of a deterioration of the glass ionomer luting cement. PMID:2664111

Arcoria, C J; DeWald, J P; Moody, C R; Ferracane, J L

1989-05-01

95

Wear of resin-modified glass ionomers: an in vitro study.  

PubMed

The purpose of this study was to evaluate the wear resistance and clinical applicability of resin-modified glass ionomer cements as restorative or fissure-sealing materials. The in vitro wear of resin-modified glass ionomers was compared to conventional glass ionomers, a resin-based sealant, and a composite resin. A three-body wear test (enamel block--polymethylmethacrylate powder--experimental dental material) was performed by 20,000 cycles with a load of 4 kgf/cm2. The depth of wear of the experimental materials was measured and calculated using a computerized laser surface scanner. The glass ionomers generally showed more wear than the resin-based sealant and the composite resin, but there was no difference in wear between resin-modified and conventional glass ionomers. Type III ionomers (used for sealant) showed lower wear resistance than type II ionomers (used for restoration). PMID:11497010

Futatsuki, M; Nozawa, M; Ogata, T; Nakata, M

2001-01-01

96

Evaluation of a Glass Ionomer Restoration to Treat Hypersensitive Cervical Anatomic Deficiencies.  

National Technical Information Service (NTIS)

The objective of the research will be to test the usefulness of a glass ionomer cement ot treat hypersensitive cervical anatomic deficiencies with a restorative material that required no tooth preparation for its application. Based on the findings of this...

E. B. Mandel

1983-01-01

97

Curing shrinkage and volumetric changes of resin-modified glass ionomer restorative materials  

Microsoft Academic Search

Objectives. The objective of the study was to evaluate initial curing shrinkage and volumetric change during water storage of six resin-modified glass ionomer cements (Dyract, DeTrey Dentsply; Fuji II LC, GC Dental Int.; Ionosit Fil, DMG; VariGlass VLC, DeTrey Dentsply; Vitremer, 3M Dental Products; Photac-Fil, ESPE), a hybrid composite (blend-a-lux, Blendax) and a chemical-cured glass ionomer cement (ChemFil Superior, DeTrey

Thomas Attin; Wolfgang Buchalla; Andrej M. Kielbassa; Elmar Hellwig

1995-01-01

98

In vitro comparison of the shear bond strength of amalgam to tooth structure using two bonding agents--lutting glass ionomer and 4-META.  

PubMed

Bonding dental amalgam to tooth structure using 4-META has become an accepted clinical procedure. Glass ionomer cements possess the ability to bind to tooth structure as well as to the components of dental amalgam. The present in vitro study evaluates the shear bond strength of amalgam to tooth structure using luting glass ionomer as a bond mediating agent, and compares with that obtained using 4-META. Results indicate that it is possible to bond amalgam to tooth structure using a thin layer of glass ionomer cement. The shear bond strength of glass ionomer cement mediated bond is significant and may be adequate for clinical application. PMID:10530186

Sheela, K; Sudeep, P T; Hegde, V; Francis, R F; Bhat, K S; Sundeep, P T

99

Dental composites/glass ionomers: the materials.  

PubMed

Most commercial dental composites contain liquid dimethacrylate monomers (including BIS-GMA or variations of it) and silica-containing compositions as inorganic reinforcing filler particles coated with methacrylate-functional silane coupling agents to bond the resin to the filler. They also contain initiators, accelerators, photo-initiators, photosensitizers, polymerization inhibitors, and UV absorbers. Durability is a major problem with posterior composites. The typical life-span of posterior composites is from three to 10 years, with large fillings usually fewer than five years. Polymerization shrinkage and inadequate adhesion to cavity walls are remaining problems. Some pulp irritation can occur if deep restorations are not placed over a protective film. Some have advocated the use of glass-ionomer cement as a lining under resin composite restorations in dentin. The concept of glass-ionomer cements (GICs) was introduced to the dental profession in the early 1970's. Current GICs may contain poly(acrylic acid) or a copolymer. Higher-molecular-weight copolymers may also be used to improve the physical properties of some GICs. Stronger and less-brittle hybrid materials have been produced by the addition of water-soluble compatible polymers to form light-curing GIC formulations. The ion-leachable aluminosilicate glass powder, in an aqueous solution of a polymer or copolymer of acrylic acid, is attacked by the hydrated protons of the acid, causing the release of aluminum and calcium ions. Salt bridges are formed, and a gel matrix surrounds the unreacted glass particles. The matrix is adhesive to mineralized tissues. Provisions must be made for maintenance of the water balance of restorations for the first 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1292462

Bowen, R L; Marjenhoff, W A

1992-09-01

100

Influence of ultrasound, with and without water spray cooling, on removal of posts cemented with resin or glass ionomer cements: An in-vitro study  

PubMed Central

Aims/objectives: To evaluate in vitro the ultrasonic vibration efficacy with and without water spray cooling on the reduction of the amount of force necessary to dislodge the cast posts cemented with resin cement and to compare it with those cemented with GIC Type I luting cement. Materials and Methods: Sixty samples were divided into six groups: groups 1, 2, 3, posts cemented with GIC; groups 4, 5, 6, posts cemented with resin; groups 1 and 4 (controls), no ultrasound; groups 2 and 5, ultrasound without water spray; and groups 3 and 6, ultrasound with water spray. Instron testing machine was used to dislodge the posts from the root canals and the data was statistically analyzed. Results: Ultrasound with water spray (group 3) among the GIC groups reduced the traction force necessary to extract posts by 53.33% whereas ultrasound without water spray (group 5) among the resin groups reduced by 59.5% compared to control. Conclusion: Ultrasound with water is more effective in removing posts cemented with GIC because of the ultrasonic energy being transferred to the post. Ultasonics without water is more effective in removing posts fixed with resin cement probably by the indirect action of heat production.

Adarsha, M S; Lata, D A

2010-01-01

101

Local and Systemic Responses To Dental Composites and Glass Ionomers  

Microsoft Academic Search

For many years, the dental profession worked mainly with rather inert restorative materials that had a limited contact with vital tissue, and the opportunity for local and systemic complications was minimal. However, conditions have changed in recent years where the two leading non-mercury-containing materials, resin composites and glass-ionomer cements, are chemically active compounds and can have detrimental effects on pulp

Harold R. Stanley

1992-01-01

102

Recharge pattern of contemporary glass ionomer restoratives  

PubMed Central

Background: As glass ionomers have the ability to reload fluoride from outside sources, the aim was to compare the recharge pattern of six glass ionomer cements after exposure to fluoride. Materials and Methods: Fuji VII, Fuji IX, Riva Pink, Riva Bleach, Ketac Fil and Fuji IX Extra were investigated. The fluoride-containing materials used were tooth paste and mouth wash (Colgate). Specimens of each material (n=15) were immersed separately in deionized water for 59 days. Then the samples of each material were divided into three groups of five each. Two groups were recharged for 2, 20 and 60 min daily during three consecutive weekly intervals and then no treatment for one week. The third group was used as control. Fluoride release measurements (?g/cm2/day) were made in every 24 h. One-way and repeated measures analysis of variance tests were used. Results: Tooth paste recharged materials showed higher level of recharge. On day 1, the difference of fluoride release from different treatment groups of different materials except for Fuji IX Extra were not significant (P>0.05). On days 7 and 14, the differences observed were significant (P<0.05) for all materials except for Fuji VII (tooth paste versus mouth wash) and Trial Fuji IX (mouth wash versus control) and on day 14 for Rvia Pink (mouth wash versus control). On days 21 and 28, the differences observed were significant for all the materials (P<0.05) except for Riva Pink (toothpaste versus mouth wash), Riva Bleach, Ketac Fil and Trial FujiI X (mouth wash versus control) on day 28. Conclusion: A time tabled schedule of application of fluoride-containing materials could help to achieve high fluoride release.

Arbabzadeh-Zavareh, Farahnaz; Gibbs, Tim; Meyers, Ian A.; Bouzari, Majid; Mortazavi, Shiva; Walsh, Laurence J.

2012-01-01

103

Fracture properties of composite and glass ionomer dental restorative materials.  

PubMed

The double-torsion technique has been used to determine critical stress intensity factor (K1c) values for a range of composites and glass ionomer cements used in restorative dentistry. From these values and determined elastic modulus (E) and tensile strength (sigma T) values, two other fracture properties: G1c, the critical strain energy release rate and a0, the inherent flaw size, have been evaluated. Glass ionomers have low K1c and high a0 values, coarse particle composites high K1c and high a0 values, microfine materials low K1c and low a0 values and fine particle composites medium to high K1c values and medium to low a0 values. Light curing materials have K1c values according to their group but tend to have lower a0 values than their chemically curing analogues. Glass ionomers have very low G1c values; however, there is no significant difference between the G1c values of the composite groups. The K1c and a0 values have been used to predict relative performance of the materials in highly stressed restorations and wear. PMID:4077896

Goldman, M

1985-09-01

104

Glass-ionomers have cariostatic effect  

Microsoft Academic Search

Design A randomised controlled trial (RCT) conducted over a period of 3 years.Intervention Either conventional glass-ionomer (Ketac-bond; 3M ESPE St. Paul, MN 55144-1000) or resin-modified glass-ionomer (Vitremer; 3M ESPE St. Paul, MN 55144-1000) sealants were applied to first permanent molars, and oral hygiene education was given. Clinical evaluations were carried out at 6, 12, 24, and 36 months after the

Paul Ashley

2003-01-01

105

The effects of maturity and dehydration shrinkage on resin-modified glass-ionomer restorations.  

PubMed

The dimensional change, including hygroscopic change, of adhesive dental materials is a clinically important topic, since excessive changes could cause debonding from tooth structure. The water balance of glass-ionomer cements arises mainly from their sensitivity to the environment; depending on the surroundings, they can gain or lose water, either of which can be potentially damaging. These effects become less noticeable as the cement ages. The effects of maturity of the newer resin-modified glass-ionomer materials and their responses to changes in moisture are unknown. Using confocal microscopy, we examined the effects of dehydration stress on the glass-ionomer/tooth interface in specimens of various degrees of maturity. Wedge-shaped cervical cavities in extracted teeth were restored with one of three resin-modified glass-ionomer restorative materials. The control specimens were restored with a conventional glass ionomer. The samples were left to mature, then sectioned and examined at 1 day, 1 wk, 1 mo, 3 mos, 6 mos, and 1 yr. After being sectioned, each specimen was examined immediately with a confocal microscope with water-immersion objectives so that the subsurface interfacial characteristics could be studied. The specimen was then allowed to dehydrate under the microscope, with further examinations at 15, 30, and 60 min. Generally, gap formation at the interface occurred within 15 min of dehydration. All materials showed a different pattern of gap change with maturity, probably due to the different setting mechanisms involved. All of them were susceptible to dehydration shrinkage up to 3 mos of maturity. At 6 mos and 1 yr, Fuji II and Fuji II LC showed insensitivity to dehydration. Vitremer and Photac-Fil showed less sensitivity to dehydration at 1 yr than at 6 mos. The results of this study of the maturing polymerized resin-modified cements have potential clinical implications in the handling of these materials; the addition of resin has not significantly reduced the glass ionomer's susceptibility to dehydration problems. PMID:9240386

Sidhu, S K; Sherriff, M; Watson, T F

1997-08-01

106

The clinical performance of a glass polyalkenoate (glass ionomer) cement used in a 'sandwich' technique with a composite resin to restore Class II cavities.  

PubMed

The use of glass polyalkenoate (GPA) cement in conjunction with composite resin using an acid etch technique is now well known and a 'sandwich' of tooth/GPA cement/composite resin has been recommended to form the cervical seal at the base of approximal boxes in Class II cavities. This paper reports on the 2-year results of a controlled clinical trial using a commercial GPA lining cement. The trial was designed to evaluate the efficacy of this 'sandwich' technique. Sixty-four restorations in the mouths of 22 patients were evaluated during the 2.5 year period of the trial. The composite resin component of the restorations performed well. Five restorations failed, all in the region of the approximal box. Four failures were related to the exposed GPA cement component of the 'sandwich'. Failure was probably related to placement difficulties of the technique. The use of GPA cement laminated with composite resin when the GPA cement was enclosed within the final restoration appeared to be a successful technique. PMID:1739506

Knibbs, P J

1992-02-01

107

Acid base surface properties of glass-ionomers determined by IGC  

NASA Astrophysics Data System (ADS)

The surface properties of several glass-ionomer restorative dental materials (GC Fuji, Chemadent G-J, Ketac Fil and Ketac Molar) were investigated by means of inverse gas chromatography. The capacity of the surface of glass-ionomers to undergo specific interactions was expressed using the specific component of free energy ?Gs as well as the parameters KA and KD to describe the ability of the cement to act both as an electron acceptor and an electron donor, respectively. The character of the examined surface was expressed with the use of the SC parameter. All these parameters were determined with a high degree of precision. It was found that the surface of glass-ionomer cements had a well-marked acidic character. The ability of the cement surface to take part in specific interactions differed with the various types of commercial products. The surface activity of the glass-ionomers investigated changed with the storage time (up to 6 months) indicating an on-going setting reaction.

Voelkel, A.; Andrzejewska, E.; Limanowska-Shaw, H.; Andrzejewski, M.

2005-05-01

108

Microleakage of glass ionomer formulations after erbium:yttrium-aluminium-garnet laser preparation.  

PubMed

The aim of this study was to investigate the microleakage in class V cavities restored with four conventionally setting glass ionomers (CGIs) and one resin-modified glass ionomer (RMGI) following erbium:yttrium-aluminium-garnet (Er:YAG) laser or conventional preparation. Four hundred class V cavities were assigned to four groups: A and B were prepared by an Er:YAG laser; C and D were conventionally prepared. In groups B and D, the surface was additionally conditioned with Ketac conditioner. Each group was divided into five subgroups according to the glass ionomer cement (GIC) used: groups 1 (Ketac Fil), 2 (Ketac Molar), 3 (Ionofil Molar), 4 (Ionofil Molar Quick) and 5 (Photac Fil Quick). After thermocycling, a 2% methylene blue solution was used as dye. Scanning electron microscope (SEM) photographs were taken to show the conditioner's effect. Complete marginal sealing could not be reached. PhotacFil showed less microleakage than the conventionally setting glass ionomer cements (CGICs) investigated. Conditioning laser-prepared cavities did not negatively influence microleakage results except for Ionofil Molar Quick. PMID:18716828

Delmé, Katleen I M; Deman, Peter J; De Bruyne, Mieke A A; Nammour, Samir; De Moor, Roeland J G

2008-08-21

109

Fluoride release and bioactivity evaluation of glass ionomer: Forsterite nanocomposite  

PubMed Central

Background: The most important limitation of glass ionomer cements (GICs) is the weak mechanical properties. Our previous research showed that higher mechanical properties could be achieved by addition of forsterite (Mg2SiO4) nanoparticles to ceramic part of GIC. The objective of the present study was to fabricate a glass ionomer- Mg2SiO4 nanocomposite and to evaluate the effect of addition of Mg2SiO4 nanoparticles on bioactivity and fluoride release behavior of prepared nanocomposite. Materials and Methods: Forsterite nanoparticles were made by sol-gel process. X-ray diffraction (XRD) technique was used in order to phase structure characterization and determination of grain size of Mg2SiO4 nanopowder. Nanocomposite was fabricated via adding 3wt.% of Mg2SiO4 nanoparticles to ceramic part of commercial GIC (Fuji II GC). Fluoride ion release and bioactivity of nanocomposite were measured using the artificial saliva and simulated body fluid (SBF), respectively. Bioactivity of specimens was investigated by Fourier transitioned-infrared spectroscopy (FTIR), scanning electronmicroscopy (SEM), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and registration of the changes in pH of soaking solution at the soaking period. Statistical analysis was carried out by one Way analysis of variance and differences were considered significant if P < 0.05. Results: The results of XRD analysis confirmed that nanocrystalline and pure Mg2SiO4 powder was obtained. Fluoride ion release evaluation showed that the values of released fluoride ions from nanocomposite are somewhat less than Fuji II GC. SEM images, pH changes of the SBF and results of the ICP-OES and FTIR tests confirmed the bioactivity of the nanocomposite. Statistical analysis showed that the differences between the results of all groups were significant (P < 0.05). Conclusion: Glass ionomer- Mg2SiO4 nanocomposite could be a good candidate for dentistry and orthopedic applications, through of desirable fluoride ion release and bioactivity.

Sayyedan, Fatemeh Sadat; Fathi, Mohammadhossein; Edris, Hossein; Doostmohammadi, Ali; Mortazavi, Vajihesadat; Shirani, Farzaneh

2013-01-01

110

The effect of ultrasound on the setting reaction of zinc polycarboxylate cements  

Microsoft Academic Search

The set of glass ionomer cement (GIC) is accelerated by application of ultrasound. Although GIC has somewhat displaced zinc\\u000a polycarboxylate cement (ZPC) in dental applications the latter is still extensively used. Like GIC, it provides direct adhesion\\u000a to tooth and can provide F release, but is more radiopaque and biocompatible than GIC. The aim of this study is to examine

S. Shahid; R. W. Billington; R. G. Hill; G. J. Pearson

2010-01-01

111

In vitro comparison of orthodontic band cements  

Microsoft Academic Search

The aim of the study was to compare the mean retentive strength of microetched orthodontic bands cemented to extracted human third molars with a modified composite, a resin-modified glass ionomer cement, and a conventional glass ionomer cement. The mode of band failure and amount of cement remaining on the tooth at deband were also assessed. Finally, survival time of bands

Declan T. Millett; Sheena Duff; Lynsey Morrison; Alistair Cummings; W. Harper Gilmour

2003-01-01

112

Clinical and microbiological performance of resin-modified glass-ionomer liners after incomplete dentine caries removal  

Microsoft Academic Search

The aims of this study were to evaluate clinically and microbiologically the effects of two resin-modified glass-ionomer cements\\u000a (RMGICs) used as liners after incomplete dentine caries removal and to identify Streptococcus mutans and Streptococcus sobrinus strains isolated from dentine samples, before and after indirect pulp treatment. Twenty-seven primary molars with deep carious\\u000a lesions, but without signs and symptoms of irreversible

Cristiane Duque; Thais de Cássia Negrini; Nancy Tomoko Sacono; Denise Madalena Palomari Spolidorio; Carlos Alberto de Souza Costa; Josimeri Hebling

2009-01-01

113

Acidic solubility of luting cements  

Microsoft Academic Search

Objectives. Chemical disintegration of luting cements can adversely affect their long term success. The aim of the present study was to assess the susceptibility of zinc phosphate cement, glass ionomer cement and resin cement to erosion at various pH values.Methods. Zinc phosphate and glass ionomer cement samples were eroded in 0.3% citric acid adjusted to pH 3.0, 4.0, 5.0, 6.0

M Eisenburger; M Addy; A Roßbach

2003-01-01

114

The effect of low dose teicoplanin-loaded acrylic bone cement on biocompatibility of bone cement.  

PubMed

Antibiotic-loaded acrylic bone cement (polymethylmethacrylate, PMMA) is used to prevent or treat infection in total joint replacement surgery. The purpose of this study was to investigate biocompatibility and cytotoxicity of the teicoplanin-loaded acrylic bone cement. Cytotoxicity examination of acrylic bone cement balls and 400 mg teicoplanin added acrylic bone cement balls conducted by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. SEM (Scanning electron microscopy) was used to observe adhesion and spreading of cells on surface of the balls. Cytotoxicity examination conducted by MTT assay on acrylic bone cement balls and teicoplanin-added acrylic bone cement balls revealed no cytotoxicity. SEM analysis put forward that cells started to proliferate and adhere on surface of the samples in both groups as a result of 48-hour incubation and that the cell proliferation over acrylic bone cement and teicoplanin-added acrylic bone cement was similar. As a consequence, there was no cytotoxicity in acrylic bone cement and teicoplanin-added acrylic bone cement groups according to results of MTT assay. On the other hand, results of SEM showed that biocompatibility of both groups was similar. In conclusion, teicoplanin-loaded bone cement did not change biocompatibility of bone cement in studied dose. PMID:23827744

Öztemür, Zekeriya; Sümer, Zeynep; Tunç, Tutku; Pazarcé, Özhan; Bulut, Okay

2013-06-01

115

Early bond strength of luting cements to a precious alloy.  

PubMed

Previous studies have reported that glass-ionomer and adhesive resin cements can bond to various alloys, while zinc phosphate cements lack this adhesive property. This study evaluated the bonding properties of three luting cements during the first seven days after cementation. Thirty cylinders were cast with a high-noble porcelain-fused-to-metal (PFM) alloy and luted in pairs with one of the cements. The joints were stored in water at 37 degrees C for one, two, or seven days before being fractured in shear. The cylinders were re-used to provide 40 joints within each test group. The data were subjected to a Weibull analysis, a curve-fitting method shown to be appropriate for comparing the bond strengths of dental materials. The results showed that the zinc phosphate cement was the weakest material, whereas the adhesive resin produced the strongest joints. Microscopic observations of the fractured samples did not reveal any specific differences between the samples in terms of their mechanism of fracture. The glass-ionomer cement reached its maximum bond strength after two days, whereas storage time had no influence on the zinc phosphate cement. The adhesive resin cement was slightly, but not significantly, weaker after one week in water. We suggest that excessive loading of restorations cemented with glass ionomer should be avoided for the first two days after the placement. The use of an adhesive resin cement can be recommended on endodontically treated teeth, but further studies are needed to evaluate its biocompatibility and adhesion to dentin. PMID:1522298

Mojon, P; Hawbolt, E B; MacEntee, M I; Ma, P H

1992-09-01

116

A comparative evaluation of dental luting cements by fracture toughness tests and fractography.  

PubMed

In recent years there has been a shift from traditional methods of investigating dental materials to a fracture mechanics approach. Fracture toughness (KIC) is an intrinsic material property which can be considered to be a measure of a material's resistance to crack propagation. Glass-ionomer cements are biocompatible and bioactive dental restorative materials, but they suffer from poor fracture toughness and are extremely susceptible to dehydration. The main objective of this study was to evaluate the fracture toughness of three types of commercially available dental cements (polyacid-modified composite resin, resin-modified and conventional glass ionomer) using a short-rod chevron-notch test and to investigate and interpret the results by means of fractography using scanning electron microscopy. Ten specimens of each cement were fabricated according to manufacturers' instructions, coated in varnish, and stored at ambient laboratory humidity, 100 per cent relative humidity, or in water at 37 degrees C for 7 days prior to preparation for testing. Results indicated that significant differences existed between each group of materials and that the fracture toughness ranged from 0.27 to 0.72 MN/m3/2. It was concluded that the resin-modified glass-ionomer cement demonstrated the highest resistance to crack propagation. Fractographs clearly showed areas of stable and unstable crack growth along the fractured surfaces for the three materials examined. PMID:11323987

Ryan, A K; Orr, J F; Mitchell, C A

2001-01-01

117

In vitro effects of ascorbate and Trolox on the biocompatibility of dental restorative materials  

Microsoft Academic Search

Previous in vitro studies on the cytotoxicity of eight dental restorative materials including composites, compomers, resin-modified glass ionomer cements and glass ionomer cements have demonstrated a depletion of intracellular glutathione in gingival fibroblasts incubated with eluates of these materials and a protective effect of N-acetylcysteine. In the present study, we investigate the effects of two other antioxidants: ascorbate and Trolox.

E Soheili Majd; M Goldberg; L Stanislawski

2003-01-01

118

Ten years' clinical evaluation of three luting cements  

Microsoft Academic Search

Objective: The aim of the present clinical longitudinal study was to observe, over 10 years, the prognosis of abutment teeth restored with fixed prostheses retained by two glass ionomer luting cements and one conventional zinc phosphate cement.Methods: Three dentists prepared 135 abutment teeth in 61 patients to retain 81 fixed prostheses. The prostheses were retained by two glass ionomer luting

A. Jokstad; I. A. Mjör

1996-01-01

119

Marginal leakage of two newer glass-ionomer-based sealant materials assessed using micro-CT  

Microsoft Academic Search

ObjectivesTo test newer glass-ionomer-based materials as sealant materials. One glass-ionomer sealant was light-cured to obtain an early setting reaction. The null-hypothesis tested was: there is no difference in marginal leakage of sealants produced with high-viscosity glass-ionomer, with and without energy supplied, and that of glass-carbomer, in comparison with resin composite sealants in vitro.

X. Chen; V. M. J. I. Cuijpers; M. Fan; J. E. F. M. Frencken

2010-01-01

120

In vitro fluoride release and the antibacterial effect of glass ionomers containing chlorhexidine gluconate.  

PubMed

Fluoride release from glass-ionomers (GI) may be important for the prevention of secondary caries. The addition of chlorhexidine gluconate (CHX) to glass-ionomer cement (3%) adds an effect that enables it to be used as a varnish for the temporary coating of surfaces at risk for caries. This study investigated the fluoride release pattern and antibacterial effect of such a material. Glassionomer luting cement powder (Aqua-Cem) was mixed with water, 10% CHX or 10% CHX with 11% tartaric acid (TA), respectively, to test specimens (6 X 1.5 mm). After setting, the specimens were immersed in 10 ml deionized water and transferred to new vials after various intervals over a period of two months. The antibacterial effect towards mutans streptococci was assessed using agar diffusion. The fluoride release was measured after two hours and after shifting the specimens to new vials 10 times during the two-month period. The mean total fluoride release was 69.02, 50.64 and 48.56 microg/cm2 from each specimen in the GI, GI-CHX and the GI-CHX-TA groups, respectively. For two-hour old specimens, the mean inhibition zone was 0, 50, 36 mm2 in the GI, GI-CHX and GI-CHX-TA groups, respectively, and, after two months, 45 mm2 in the GI-CHX group and 19 mm2 in the GI-CHX-TA group. It can be concluded that the addition of CHX and CHX-TA adds antibacterial properties to GI and the release of fluoride is decreased. PMID:19051864

Hoszek, A; Ericson, D

121

Synthesis and application of novel multi-arm poly(carboxylic acid)s for glass-ionomer restoratives.  

PubMed

We have developed a novel glass-ionomer cement system composed of multi-arm poly(acrylic acid-co-itaconic acid)s. These polyacids were synthesized via a chain-transfer polymerization reaction using newly synthesized multi-arm chain-transfer agents. The cements formulated with the multi-arm polyacids showed significantly lower viscosities in water as compared to those formulated with the linear polyacids. Due to the lower viscosities, the MW of the polyacids can be significantly increased for enhanced mechanical strengths, while keeping the ease of mixing and handling. The experimental cements showed significantly improved compressive strengths as compared to Fuji II after aged in water for 3 months. PMID:19033326

Xie, Dong; Zhao, Jun; Weng, Yiming

2008-11-25

122

N-vinylpyrrolidone modified glass-ionomer resins for improved dental restoratives  

NASA Astrophysics Data System (ADS)

The studies described in this dissertation focus on improvement of mechanical properties of current glass-ionomer cements. Thermal properties and microstructures of the cements were correlated with their mechanical strengths. The first study evaluated mechanical properties of selected commercial glass-ionomer cements and examined their microstructures. The results showed that resin-modified glass-ionomer cements (RM GICs) exhibited much higher flexural (FS) and diametral tensile strengths (DTS), compared to conventional GICs (C GICs). In addition, they exhibited comparable compressive strength (CS), relatively low microhardness and less wear resistance than C GICs. The C GICs exhibited brittle behavior, whereas the RM GICs underwent substantial plastic deformation in compression. The mechanical properties of the GICs were closely related to their microstructures. Factors such as the density of the microstructure, the integrity of the interface between the glass particles and polymer matrix, particle size and the number and size of voids have important roles in determining the mechanical properties. The second study evaluated thermal properties of these GICs. The results showed that the RM GICs exhibited higher thermal transition temperatures than those of the C GICs, thermal expansion coefficients of these cements were close to those of human teeth, and the indentation creep of the RM GICs were higher than the C GICs. The third study explored and evaluated the effect of a water-soluble monomer, N-vinylpyrrolidone (NVP), on the performance of current C GICs, indicating a significant improvement in both mechanical and working properties. The fourth study demonstrated the process of determining the optimal molar ratio of the NVP-containing copolymers, using design of experiment. The results showed that the optimal molar ratio for these copolymers was 7:1:3 for poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone), based on the FS test. The molar ratio of 8:2:1 (AA:IA:NVP) was considered as the best molar ratio for these copolymers, based on the DTS and CS tests. The fifth study formulated the NVP-containing RM GICs using a statistical design of experiment. The results indicated that the best graft ratio for 2-isocyanatoethyl methacrylate (IEM) in this system was 15% of the terpolymer by a molar ratio. The optimal formulation was found to be at the weight ratio of 55:15:30 (RM NVP-containing terpolymer: 2-hydroxyethyl methacrylate (HEMA): Hsb2O). Stress-strain curves showed that a relatively high amount of water in the formulation led to higher elastic modulus and proportional limit and lower malleability, whereas a relatively high amount of HEMA gave the opposite results. The sixth study evaluated the NVP modified GICs (NVPM GICs) with the best molar ratios and optimal formulations in the mechanical, thermal and working properties. The results showed that the effect of molecular weight on mechanical properties of the NVPM GICs were evident. Different glass powders exhibited different effects on properties of the NVPM GICs, due to different compositions, size and affinity. Powder/liquid ratios had significant effects on the mechanical properties of NVPM GICs, especially on FS. P/W ratios are only beneficial to the NVPM GICs mixed with the Fuji II glass powders. The NVPM GICs showed a higher WT than the models, due to water retention of the NVP ring. Thermal expansion coefficients for the NVPM GICs were close to those for the natural tooth. Mismatch between the glass powders used and the polymer matrix was a big concern in this study and should be solved in the future.

Xie, Dong

123

Enamel and Cementum Fluoride Uptake from a Glass Ionomer Cement  

Microsoft Academic Search

Class V cavities were prepared at the cemento-enamel junction on the facial surfaces of 45 extracted human central maxillary incisors. Enamel samples for analysis were obtained by means of perchloric acid etching from circular areas, 1 mm in diameter, positioned 1.5, 3.5, 5.5, and 7.5 mm from the incisal and apical margins of the restorations, respectively. The preparations were filled

D. H. Retief; E. L. Bradley; J. C. Denton; P. Switzer

1984-01-01

124

Comparative quantitative and qualitative assessment of the marginal adaptation and apposition of bonded amalgam restorations using luting glass ionomer and 4-META adhesive liner under a scanning electron microscope. An in vitro study.  

PubMed

The present invitro study was conducted to assess the marginal adaptation and apposition of amalgam restorations bonded to tooth structure, using freshly mixed luting glass ionomer cement (type 1) and compared with the much documented material--Amalgam bond (4-META). Twelve freshly extracted human premolar teeth were used and class V cavities were prepared on the buccal and lingual surfaces of twelve teeth for the experimental groups. Buccal cavities (class V) were prepared on twelve other teeth for the control group. In the control, two coats of cavity varnish was applied as the liner. The experimental groups were lined with freshly mixed luting glass ionomer in twelve buccal cavities and amalgam bond adhesive liner in twelve lingual cavities. The amalgam was then condensed before the liner sets in all the cavities. The teeth were sectioned and mounted on aluminum stubs and then placed in the scanning electron microscope and were observed. The results of the study showed that marginal interface gaps were higher with luting glass ionomer and cavity varnish than with amalgam bond as the liner. The results were statistically not significant. All the three groups were effected by the severe thermal stresses introduced by the microscopy with the glass ionomer cement suffering the worst. The present investigation confirms that glass ionomer cement (type 1) can be effectively used as a bonding agent between amalgam and the tooth when it is painted onto the cavity walls after which the amalgam is condensed immediately, prior to its setting. Its ability to bond amalgam to the tooth structure with minimal gaps is comparable to that of amalgam bond. PMID:10865391

Abraham, M M; Sudeep, P T; Bhat, K S

125

The effect of cement type and mixing on the bi-axial fracture strength of cemented aluminous core porcelain discs  

Microsoft Academic Search

Objectives. Luting agents in current use include zinc phosphate, zinc polycarboxylate, conventional glass-ionomer, resin-modified glass-ionomer and resin composite cements. Dental cements may be used in practice with a wide range of mixing ratios. Accordingly, the impact of cement type and mixing on the strength of alumina reinforcing porcelain was investigated.Methods. Standard Vitadur-N core porcelain disc specimens were coated with different

Garry J. P Fleming; Omar Narayan

2003-01-01

126

Microleakage of Class V resin-modified glass ionomer and compomer restorations  

Microsoft Academic Search

Statement of problem. Resin-modified glass ionomers and polyacid-modified resin composites (compomers) have been introduced to provide esthetic restorations. However, there is concern about the marginal sealing ability of these materials, especially at the dentin (cementum) aspects of restorations. Purpose. This in vitro study evaluated the microleakage of Class V restorations made with resin-modified glass ionomers or a compomer. Material and

Manuel Toledano; Estrella Osorio; Raquel Osorio; Franklin García-Godoy

1999-01-01

127

In vitro toothbrush-dentifrice abrasion of resin-modified glass ionomers  

Microsoft Academic Search

Objectives. This study was conducted to compare the rate of abrasive wear and change in surface roughness of resin-modified and conventional acid-base glass ionomers when subjected to toothbrush-dentifrice abrasion.Methods. Two resin-modified and two conventional glass ionomers were used. Samples of a high-copper amalgam and a hybrid resin composite were used as reference materials. Specimens of each material were prepared and

Yasuko Momoi; Kunitsugu Hirosaki; Atsushi Kohno; John F. McCabe

1997-01-01

128

Conventional glass ionomers as posterior restorations. A status report for the American Journal of Dentistry.  

PubMed

The search for a material to replace amalgam continues as a major quest in materials science. Resin composites may offer one solution but an alternative class of material, the glass ionomer cements (GICs) may have some potential for fulfilling this role. GICs were first introduced to the dental profession in 1976, and have now become an accepted part of the dental armamentarium, especially for use in low load bearing situations. They possess a low coefficient of thermal expansion similar to that of tooth structure, physicochemical bonding to both enamel and dentin, and the release of fluoride ions into the adjacent tooth tissue. These properties help to reduce marginal leakage and may contribute to a reduced incidence of recurrent decay in the restored tooth. Fluoride released into the ambient fluids has a caries-preventive effect in neighboring teeth by enhancing remineralization and inhibiting demineralization of the dental hard tissues. The main criticisms of the GICs are their brittleness, poor surface polish, porosity and surface wear. To overcome some of these deficiencies, considerable attention has been directed at improving their physical properties, especially with the addition of metal powders, the metal-modified GICs. Different metal powders have been tried, including alloys of silver and tin, pure silver, gold, titanium, palladium and stainless steel. There is conflicting data as to whether or not these materials are sufficiently strong for use in high stress restorations, especially their potential use as replacement materials for amalgam fillings. PMID:9823085

Naasan, M A; Watson, T F

1998-02-01

129

Dentin surface treatment and shear bond strength of a light-cured glass ionomer.  

PubMed

This study evaluated the effect of dentin surface treatment with polyacrylic acid on the shear bond strength of Fuji Lining LC light-cured glass ionomer lining cement (GIC). A total of 40 human, noncarious extracted permanent molars stored in distilled water were used. A flat buccal dentin surface was ground wet on 600-grit silicon carbide paper. The teeth were then randomly distributed into four groups of 10 teeth each: Group 1: dentin rinsed with distilled water, dried with oil-free compressed air, placement of cylindrical GIC samples and sheared at 15 minutes post-curing. Group 2: same as group 1, but sheared 7 days post-curing. Group 3: dentin treated with GC Conditioner for 10 seconds, rinsed with distilled water, dried with oil-free compressed air, placement of the GIC and sheared 15 minutes post-curing. Group 4: same as group 3, but sheared 7 days post-curing. The GIC was mixed in a 1:1 powder-liquid ratio. The samples were stored in distilled water until sheared with an Instron. The results revealed that dentin surface treatment with the polyacrylic acid significantly increased the shear bond strength to dentin when tested at 7 days post-curing. PMID:1299259

Garcia-Godoy, F

1992-10-01

130

Genotoxic and cytotoxic effects of different types of dental cement on normal cultured human lymphocytes  

Microsoft Academic Search

In this study we have investigated the genotoxic and cytotoxic effects of eluates derived from different types of commercially available dental cements, including glass ionomer cements (GICs) (Ketac Cem\\/3M ESPE and GC Fuji I\\/GC Corp), resin-modified glass ionomer cements (RM-GICs) (RelyX Luting\\/3M ESPE and Vitrebond\\/3M ESPE) and dual-cure resin cements (RCs) (Variolink II\\/ Ivoclar-Vivadent and Panavia F 2.0\\/Kuraray) on normal

A. Bakopoulou; D. Mourelatos; A. S. Tsiftsoglou; N. P. Giassin; E. Mioglou; P. Garefis

2009-01-01

131

Bioglass: A novel biocompatible innovation.  

PubMed

Advancement of materials technology has been immense, especially in the past 30 years. Ceramics has not been new to dentistry. Porcelain crowns, silica fillers in composite resins, and glass ionomer cements have already been proved to be successful. Materials used in the replacement of tissues have come a long way from being inert, to compatible, and now regenerative. When hydroxyapatite was believed to be the best biocompatible replacement material, Larry Hench developed a material using silica (glass) as the host material, incorporated with calcium and phosphorous to fuse broken bones. This material mimics bone material and stimulates the regrowth of new bone material. Thus, due to its biocompatibility and osteogenic capacity it came to be known as "bioactive glass-bioglass." It is now encompassed, along with synthetic hydroxyapatite, in the field of biomaterials science known as "bioactive ceramics." The aim of this article is to give a bird's-eye view, of the various uses in dentistry, of this novel, miracle material which can bond, induce osteogenesis, and also regenerate bone. PMID:23833747

Krishnan, Vidya; Lakshmi, T

2013-04-01

132

Bioglass: A novel biocompatible innovation  

PubMed Central

Advancement of materials technology has been immense, especially in the past 30 years. Ceramics has not been new to dentistry. Porcelain crowns, silica fillers in composite resins, and glass ionomer cements have already been proved to be successful. Materials used in the replacement of tissues have come a long way from being inert, to compatible, and now regenerative. When hydroxyapatite was believed to be the best biocompatible replacement material, Larry Hench developed a material using silica (glass) as the host material, incorporated with calcium and phosphorous to fuse broken bones. This material mimics bone material and stimulates the regrowth of new bone material. Thus, due to its biocompatibility and osteogenic capacity it came to be known as “bioactive glass-bioglass.” It is now encompassed, along with synthetic hydroxyapatite, in the field of biomaterials science known as “bioactive ceramics.” The aim of this article is to give a bird's-eye view, of the various uses in dentistry, of this novel, miracle material which can bond, induce osteogenesis, and also regenerate bone.

Krishnan, Vidya; Lakshmi, T.

2013-01-01

133

Mechanical and In Vitro Biocompatibility of Brushite Cement Modified by Polyethylene Glycol.  

PubMed

Brushite (dicalcium phosphate dihydrate, DCPD) cement, owing to its high solubility in physiological condition and ability to guide new bone formation, is widely used to treat bone defects. In the present study, we have evaluated the effects of poly ethylene glycol (PEG) addition on the setting time, compressive strength and in vitro biocompatibility of brushite cement. The brushite cements were prepared by mixing ?-tricalcium phosphate [?-TCP, Ca(3)(PO(4))(2)] and monocalcium phosphate monohydrate [MCPM, Ca(H(2)PO(4))(2). H(2)O]. PEG was introduced at 2.0 and 5.0 wt% with the liquid. Introduction of PEG resulted in marginal increase in both initial and final setting time; however, significantly affected the compressive strength. Effects of PEG incorporation on in vitro biocompatibility of brushite cements were studied by using human fetal osteoblast cells (hFOB) cells. Field emission scanning electron microscope (FESEM) images and immunohistochemical analysis indicated that pure and PEG incorporated brushite cement facilitates cell adhesion, proliferation and differentiation. Fewer cells expressed vinculin protein with increased PEG content in the cement. Cell proliferation was found to decrease with increased PEG concentration while the cell differentiation increased with PEG content. Our results provide a better understanding of in vitro biocompatibility of PEG added brushite cements that can be used to customize the cement compositions based on application need. PMID:23139441

Roy, Mangal; Devoe, Ken; Bandyopadhyay, Amit; Bose, Susmita

2012-12-01

134

Biocompatible Cement Containing Reactive Calcium Phosphate Nanoparticles and Methods for Making and Using Cement.  

National Technical Information Service (NTIS)

A cement powder is disclosed that contains reactive tricalcium phosphate nanoparticles and other ingredients required to form a cementous material. Methods of making the reactive tricalcium phosphate nanoparticles, the cement powder, the cement paste, and...

B. R. Genge G. R. Sauer L. Wu R. Genge R. E. Wuthier

2004-01-01

135

Investigation into the Depth of Cure of Resin-Modified Glass-Ionomer Restorative Materials.  

National Technical Information Service (NTIS)

This investigation involved an attempt at delineating the depth of cure of resin-modified glass-ionomer restorative dental materials. Samples of different thicknesses using Vitremer Core Material and Restorative (3M/ESPE), Fuji II LC (GC America), and Pho...

H. W. Roberts

2006-01-01

136

Dentin Surface Treatment and Bond Strength of Glass Ionomers. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

This study evaluated the effect of dentin surface treatment on shear bond strengths of two visible light activated glass ionomer restorative materials to dentin. Cylinders of Fuji II LC and VariGlass VLC were bonded to dentin surfaces that were untreated,...

D. G. Charlton C. W. Haveman

1994-01-01

137

[Effect of dental luting cements from the viewpoint of cell recovery (in vitro)].  

PubMed

Cell recovery of four cell lines [L-929 cells, HEp-2 cells, Gin-1 cells and the cells from human dental pulp tissues (Hp cells)] was examined after exposure to four zinc phosphate cements, five polycarboxylate cements, three glass ionomer cements, five resin based cements and one zinc oxide-eugenol.EBA cement. Phosphate cements, glass ionomer cements and zinc oxide-eugenol.EBA cement were markedly cytotoxic to the four cell lines 3 hours and 24 hours after mixing. Polycarboxylate cements considerably inhibited cell recovery of the three types of cells except Hp cells even 24 hours after mixing, compared to the gradual recovery of Hp cells after mixing. Two of the resin based cements inhibited cell recovery, while the three others allowed moderate cell recovery. The pH values of the medium used for the experiments was 6.6-6.8 for phosphate cements, glass ionomer cements and zinc oxide-eugenol.EBA cements. Polycarboxylate cements had no effect on the pH. On the other hand, in resin based cements the pH was shifted from acidic to basic. The solubility of the materials used was, in decreasing order: glass ionomer cements, zinc oxide-eugenol.EBA cement and one of the resin based cements, polycarboxylate cements, phosphate cements and another resin based cement, and the other three of resin based cements (lowest). The difference in cell recovery was considered to be due to composition and solubility of the materials. PMID:2133360

Yokoyama, K; Imai, K

1990-09-01

138

Biocompatibility and resorption of a brushite calcium phosphate cement.  

PubMed

A hydraulic calcium phosphate cement with beta-tricalcium phosphate (TCP) granules embedded in a matrix of dicalcium phosphate dihydrate (DCPD) was implanted in experimentally created defects in sheep. One type of defect consisted of a drill hole in the medial femoral condyle. The other, partial metaphyseal defect was located in the proximal aspect of the tibia plateau and was stabilized using a 3.5 mm T-plate. The bone samples of 2 animals each per group were harvested after 2, 4, 6 and 8 weeks. Samples were evaluated for cement resorption and signs of immediate reaction, such as inflammation, caused by the cement setting in situ. Differences regarding these aspects were assessed for both types of defects using macroscopical, radiological, histological and histomorphometrical evaluations. In both defects the brushite matrix was resorbed faster than the beta-TCP granules. The resorption front was followed directly by a front of new bone formation, in which residual beta-TCP granules were embedded. Cement resorption occurred through (i) extracellular liquid dissolution with cement disintegration and particle formation, and (ii) phagocytosis of the cement particles through macrophages. Signs of inflammation or immunologic response leading to delayed new bone formation were not noticed at any time. Cement degradation and new bone formation occurred slightly faster in the femur defects. PMID:15701367

Theiss, Felix; Apelt, Detlef; Brand, Bastian; Kutter, Annette; Zlinszky, Katalin; Bohner, Marc; Matter, Sandro; Frei, Christian; Auer, Joerg A; von Rechenberg, Brigitte

2005-07-01

139

Longevity and Cariostatic Effects of Everyday Conventional Glass-ionomer and Amalgam Restorations in Primary Teeth: Three-year Results  

Microsoft Academic Search

The aim of this study was to compare the longevity and cariostatic effects of everyday conventional glass-ionomer and amalgam restorations in primary teeth. The materials consisted of 515 Ketac-Fil glass-ionomer restorations and 543 Dispersalloy amalgam restorations prepared in 666 children, from 3 to 13 years of age, by 14 dentists within the Danish Public Dental Health Service in the municipalities

V. Qvist; L. Laurberg; A. Poulsen; P. T. Teglers

1997-01-01

140

Adhesion of a glass-ionomer root canal sealer to the root canal wall.  

PubMed

Glass-ionomer root canal sealer is commonly used because of its chemical bonding and favorable physical characteristics when bonding to dentin. This study was designed to determine the tensile bond strength of a glass-ionomer sealer (Ketac Endo, Espe, Seefeld, Germany) on root canal walls after pretreatment with different conditioners. Flat inner surfaces of root canal specimens were prepared. The specimens were divided into five groups of 10 teeth, and the groups were conditioned with one of the following smear layer removal solutions: 15% EDTA/NaOCl, 10% polyacrylic acid, 35% phosphoric acid, 6% citric acid, and 5.25% NaOCl as a control. Then the exposed root canal areas were coated with Ketac-Endo. Tensile bonding was measured using a universal testing machine until ultimate failure was obtained. The groups that were treated with phosphoric acid and citric acid showed significantly higher bond strengths than the groups that were treated with 15% EDTA and polyacrylic acid (p < 0.05). Bonding to dentin without smear layer removal (NaOCl group) was too low to be measured in the testing apparatus. Scanning electron microscopy confirmed that phosphoric and citric acids were more effective in removing smear layer than EDTA or polyacrylic acid. The result supported the view that pretreatment with phosphoric acid or citric acid should be used in association with glass-ionomer root canal sealer to achieve the most effective removal of the smear layer and to provide better adhesion. PMID:11487144

Timpawat, S; Harnirattisai, C; Senawongs, P

2001-03-01

141

Fracture toughness and fractography of dental cements, lining, build-up, and filling materials.  

PubMed

The plane strain fracture toughness (K1c) at 23 degrees C and the fractography of zinc phosphate and zinc polycarboxylate cements, buffered glass ionomer liner, amalgam alloy admixed glass ionomer build-up material, and glass ionomer, microfilled and conventionally filled bis-GMA resin composite filling materials were analyzed by elastic-plastic short-rod and scanning electron microscopy methodologies. Results indicated that significant differences occurred in their K1c's from the lowest to the highest in the following groups of materials, (i) buffered glass ionomer, (ii) zinc phosphate, glass ionomer, zinc polycarboxylate, and alloy mixed glass ionomer, (iii) microfilled resin, and (iv) conventionally filled resin. All materials except the microfilled resin, which fractured via crack jumping, fractured via smooth crack advance. Filler debonding without any crack inhibiting process was related to materials with low K1c values. The incorporation of either buffering compounds or alloy particles into glass ionomer had no beneficial effect upon fracture toughness. This was in contrast to microfilled and conventionally filled resins where either crack blunting or crack pinning processes, respectively, were likely involved with their increased K1c's. For microfilled resin, distinct radial zones positioned around the chevron apex and characterized by plastically deformed deposited material were related to distinct crack jumps that occurred in the load versus displacement behavior. Finally, for the two remaining materials of zinc phosphate and polycarboxylate, particle cleavage and matrix debonding for the former and shear yielding for the latter occurred. PMID:2402605

Mueller, H J

1990-06-01

142

[Haemotoxicity of dental luting cements].  

PubMed

A glass ionomer luting cement (AquaCem) shows a relatively low haemolytic activity in comparison with two zinc phosphate cements. Especially the initial irritation by this cement is smaller. Although it is possible that AquaCem particularly, in unfavourable cases, may damage the pulpa dentin system; this is due to the slowly decrease of the haemolytic activity with increasing of the probes. We found that Adhesor showed in dependence of the batches a varying quality. PMID:2626769

Anders, A; Welker, D

1989-06-01

143

The effect of incremental versus bulk fill techniques on the microleakage of composite resin using a glass-ionomer liner.  

PubMed

Incremental placement of composite resin has been suggested to reduce microleakage, particularly at the gingival margin of class 5 cervical restorations. It has become clinically advantageous to place a glass-ionomer liner over dentin to further minimize microleakage resulting from a bond between the dentin and glass ionomer, and glass ionomer and resin. The objective of this study was to compare the microleakage behavior of three hybrid composite/bonding agent systems using bulk and incremental filling techniques utilizing a glass-ionomer liner. This was accomplished in vitro using freshly extracted bovine incisors and a Ca45 radioisotope and autoradiography. Sixty bovine incisors were divided into six experimental groups of 10 specimens per group. Class 5 preparations were cut at the cementoenamel junction and restored with the appropriate combination of Herculite XR/Bondlite, P50/Scotchbond 2, or Pertac Hybrid/Pertac Bond. All teeth were lined with the glass ionomer Ketac Bond before the final restoration was placed. The samples were finished and stored for 24 hours in distilled water before thermocycling. The samples were tested for microleakage using a Ca45 radioisotope technique and autoradiography. Incisal (enamel) and gingival (dentin) margins were scored separately for microleakage but grouped for statistical analysis. Results were analyzed using the Kruskal-Wallis H test. Pertac Hybrid exhibited more leakage than Herculite XR or P50. The difference between microleakage of bulk and incremental filling techniques was only significant for P50. PMID:1289865

Puckett, A; Fitchie, J; Hembree, J; Smith, J

144

Comparative evaluation of tensile bond strength and microleakage of conventional glass ionomer cement, resin modified glass ionomer cement and compomer: An in vitro study  

PubMed Central

Aim: The purpose of this study was to evaluate and compare the tensile bond strength and microleakage of Fuji IX GP, Fuji II LC, and compoglass and to compare bond strength with degree of microleakage exhibited by the same materials. Materials and Methods: Occlusal surfaces of 96 noncarious primary teeth were ground perpendicular to long axis of the tooth. Preparations were distributed into three groups consisting of Fuji IX GP, Fuji II LC and Compoglass. Specimens were tested for tensile bond strength by mounting them on Instron Universal Testing Machine. Ninety-six primary molars were treated with Fuji IX GP, Fuji II LC, and compoglass on box-only prepared proximal surface. Samples were thermocycled, stained with dye, sectioned, and scored for microleakage under stereomicroscope. ANOVA and Bonferrani correction test were done for comparisons. Pearson Chi-square test and regression analysis were done to assess the association between the parameters. Results: Compoglass showed highest tensile strength and Fuji II LC showed least microleakage. There was a significant difference between the three groups in tensile strength and microleakage levels. The correlation between tensile strength and microleakage level in each group showed that there was a significant negative correlation only in Group 3. Conclusion: Fuji II LC and compoglass can be advocated in primary teeth because of their superior physical properties when compared with Fuji IX GP.

Rekha, C. Vishnu; Varma, Balagopal; Jayanthi

2012-01-01

145

ART restorations and glass ionomer sealants in Zimbabwe: survival after 3 years.  

PubMed

Atraumatic restorative treatment (ART) consists of removing demineralised tooth tissues with hand instruments only, restoring the prepared cavity and sealing the adjacent pits and fissures with an adhesive filling material. This relatively painless, no-handpiece, minimal intervention approach to controlling dental caries is described. ART was applied in an oral health care programme in Zimbabwe that was carried out amongst secondary school students from 1994 to 1997. A new glass ionomer (Fuji IX) was used as the restorative and sealant material. Sealants were placed in high caries risk students using the 'press-finger' technique. A total of 297 one-surface ART restorations and 95 glass ionomer sealants were placed in 142 and 66 students, respectively. After 3 years, the lost-to-follow-up percentages for one-surface ART restorations and glass ionomer sealants were 30.6% and 30.5%, respectively. Actuarial (life table) analysis resulted in 3-year survival rates of one-surface ART restorations of 88.3% (95% CI: 92.4%-84.2%), ranging from 94.3% to 65.4% per operator. A total of 28 ART restorations placed in 25 students failed. Reasons for failure related to the material and the operator (11 restorations or 5.3% each), and to caries adjacent to the restoration (one restoration or 0.5%). Reasons for failure were not recorded for five restorations (2.3%). Sealants were placed on surfaces diagnosed as early enamel lesions. After 3 years, 71.4% (95% CI: 81.7%-61.1%) of the fully and partially retained sealants survived with a range of 100% to 55.6% per operator. Of the sealed surfaces 96.3% (95% CI: 100%-92.2%) survived 3 years without developing caries. Experienced operators placed better ART restorations than inexperienced operators. This study has demonstrated that ART with a glass ionomer restorative material and sealants provided high quality preventive and restorative dental care to this student population. ART has become one of the treatment modalities available to oral health workers in managing dental caries. PMID:9870536

Frencken, J E; Makoni, F; Sithole, W D

1998-12-01

146

Tissue response to experimental dental cements prepared from a modified powder glass composition.  

PubMed

The present work seeks to evaluate the biocompatibility of experimental glass ionomer cements (GIC) prepared from niobium-calcium fluoro-alumino-silicate glass powder and two commercial GICs. The GICs were implanted into the subcutaneous connective tissue of sixty rats. The rats were sacrificed during four varying time periods: 7, 15, 30, and 60 days and histopathological examinations were then performed. The Kruskal-Wallis test was performed to evaluate any significant differences between the materials. Additionally, multiple comparisons of the mean rank were also carried out using the Dunn test (p<0.05). No significant differences were observed that one GIC was superior to the other. The tissue response for all of the GICs tested was similar in all the periods examined. PMID:22864211

Boaventura, Juliana Maria Capelozza; Bertolini, Marcio José; Padovani, Gislaine Cristina; de Oliveira, Maria Rita Brancini; Zaghete, Maria Aparecida; de Oliveira Júnior, Osmir Batista; de Andrade, Marcelo Ferrarezi

2012-01-01

147

Kinetics of fluoride release from zinc oxide-based cements  

Microsoft Academic Search

Considerable attention has been given to the release of the cariostatic fluoride ion from glass-based dental cements (dental silicate and glass ionomer). In these, the total available fluoride content is not precisely known since fluorine is distributed between the cross-linked aqueous salt matrix, partially dissolved glass, and undissolved glass. In analogous cements based on zinc oxide the fluoride is added

R. W. Billington; P. C. Hadley; J. A. Williams; G. J. Pearson

2001-01-01

148

Adhesion of Polycarboxylate-based Dental Cements to Enamel: An in vivo Study  

Microsoft Academic Search

The bond strength of two polycarboxylate and two glass ionomer cements to enamel in vivo has been measured by a tensile test method. The four cements were used to cement small stainless steel cylinders onto the facial surfaces of 11 and 21. The cylinders were removed by a tensile force applied by a handpiece containing a semi-conductor sensory unit.The results

T. Jemt; P. A. Stålblad; G. Øilo

1986-01-01

149

Early Bond Strength of Luting Cements to a Precious Alloy  

Microsoft Academic Search

Previous studies have reported that glass-ionomer and adhesive resin cements can bond to various alloys, while zinc phosphate cements lack this adhesive property. This study evaluated the bonding properties of three luting cements during the first seven days after cementation. Thirty cylinders were cast with a high-noble porcelain-fused-to-metal (PFM) alloy and luted in pairs with one of the cements. The

P. Mojon; E. B. Hawbolt; M. I. MacEntee; P. H. Ma

1992-01-01

150

Comparison of effect of desensitizing agents on the retention of crowns cemented with luting agents: an in vitro study  

PubMed Central

PURPOSE Many dentists use desensitizing agents to prevent hypersensitivity. This study compared and evaluated the effect of two desensitizing agents on the retention of cast crowns when cemented with various luting agents. MATERIALS AND METHODS Ninety freshly extracted human molars were prepared with flat occlusal surface, 6 degree taper and approximately 4 mm axial length. The prepared specimens were divided into 3 groups and each group is further divided into 3 subgroups. Desensitizing agents used were GC Tooth Mousse and GLUMA® desensitizer. Cementing agents used were zinc phosphate, glass ionomer and resin modified glass ionomer cement. Individual crowns with loop were made from base metal alloy. Desensitizing agents were applied before cementation of crowns except for control group. Under tensional force the crowns were removed using an automated universal testing machine. Statistical analysis included one-way ANOVA followed by Turkey-Kramer post hoc test at a preset alpha of 0.05. RESULTS Resin modified glass ionomer cement exhibited the highest retentive strength and all dentin treatments resulted in significantly different retentive values (In Kg.): GLUMA (49.02 ± 3.32) > Control (48.61 ± 3.54) > Tooth mousse (48.34 ± 2.94). Retentive strength for glass ionomer cement were GLUMA (41.14 ± 2.42) > Tooth mousse (40.32 ± 3.89) > Control (39.09 ± 2.80). For zinc phosphate cement the retentive strength were lowest GLUMA (27.92 ± 3.20) > Control (27.69 ± 3.39) > Tooth mousse (25.27 ± 4.60). CONCLUSION The use of GLUMA® desensitizer has no effect on crown retention. GC Tooth Mousse does not affect the retentive ability of glass ionomer and resin modified glass ionomer cement, but it decreases the retentive ability of zinc phosphate cement.

Pandharinath, Dange Shankar; Arun, Khalikar; Smita, Vaidya

2012-01-01

151

In vitro bioactivity and biocompatibility of calcium phosphate cements using Hydroxy-propyl-methyl-Cellulose (HPMC)  

NASA Astrophysics Data System (ADS)

In this study, the bioactivity and biocompatibility of new calcium phosphate bone cements (CPC) using Hydroxy-propyl-methyl-Cellulose (HPMC) was evaluated to understand the effect of HPMC on bone-bonding apatite formation and biocompatibility. In vitro bioactivity was investigated by incubating the CPC samples containing different ratios of HPMC (0%, 2% and 4% HPMC) in simulated body fluid (SBF) for 2, 7, 14 and 28 days. The formation of bone like apatite was confirmed on CPC surfaces by SEM and XRD analysis. Higher HPMC content of CPC showed faster apatite deposition in SBF. A high Ca ion dissolution profile was also reported with an increase of pH in all samples in SBF. The apatite formation ability of these CPC samples was found to be dependent on both surface chemistry and immersion time in SBF. The In vitro cytotoxicity test showed that the CPC samples with 4% HPMC were fairly cytocompatible for fibroblast L-929 cells. SEM images showed that MG-63 cells were successfully attached to the CPC samples and well proliferated.

Jyoti, M. Anirban; Thai, Van Viet; Min, Young Ki; Lee, Byong-Taek; Song, Ho-Yeon

152

[Study on dental cements. 1. The cored structure of three luting cements obtained by using Cryo-SEM and image analyzer].  

PubMed

The polished surfaces of three set dental cements for luting (zinc phosphate cement, polycarboxylate cement, and glass ionomer cement) were observed by cryo-SEM at a specimen temperature of -160 degrees C to prevent damage of the cement specimens and also the specimens were analyzed by EDX. Furthermore, the SEM composition images of the polished cement surface were transferred to an image analyzer to obtain the core/matrix area ratio of the set cements. 1. The polished surface of set dental cement could be clearly observed by cryo-SEM without damaging the cement specimens. 2. The image analyzer showed that the core/matrix area ratio of the zinc phosphate cement and the glass ionomer cement was approximately 2 to 8, whereas that of the polycarboxylate cement was approximately 3 to 7. 3. The elements detected in the zinc phosphate cement were Ca, Zn, Mg, Al, and P, in the polycarboxylate cement were Ca, Zn, Mg, Si, and Sr, and in the glass ionomer cement were Al and Si. PMID:2135511

Hosoda, H; Yamada, T; Nakajima, M; Perinka, L

1990-03-01

153

Influence of storage conditions and effect of metal priming agents on bond strength of resin-modified glass ionomers to gold alloy.  

PubMed

This study evaluated the influence of water storage conditions and the effect of metal priming agents on bond strength and durability of four luting agents joined to gold alloy. Disk specimens were cast from a gold alloy (Degudent U), and the surfaces were ground flat with abrasive paper. Three surface conditions employed were: unprimed, primed with Alloy Primer, and primed with Metaltite. Three resin-modified glass ionomers (RMGIs; Vitremer Luting Cement, Fuji Lute, and Xeno Cem Plus) and a resin adhesive (Super-Bond C&B) were used for bonding the gold alloy. Unprimed specimens bonded either with Fuji Lute or with Super-Bond C&B were immersed in water at 5, 37, and 55 degrees C for 7 days, or subjected to thermocycling (5,000 cycles; 5 degrees C, 1 min and 55 degrees C, 1 min). In addition, specimens were bonded with 12 combinations comprising three surface conditions and four luting agents, and thermocycled for 20,000 cycles. Shear bond strengths were then determined and analyzed statistically. Thermocycling was useful for evaluation of the bonding durability of RMGIs. Application of two metal priming agents combined with RMGIs considerably enhanced the bond strength to the gold alloy. PMID:19325196

Oshima, Akiko

2009-03-01

154

Evaluation of surface roughness and hardness of different glass ionomer cements  

PubMed Central

Objectives: The aim of this study was to evaluate surface roughness and hardness of a nanofiller GIC, a resin-modified GIC, three conventional GICs, and a silver-reinforced GIC. Methods: For each material, 11 spcecimens were prepared and then stored in distilled water at 37 °C for 24 h. The surface roughness of 5 specimens was measured using a surface profilometer before polishing and after polishing with coarse, medium, fine, superfine aluminum oxide abrasive Sof-Lex discs respectively. The hardness of the upper surfaces of the remaining 6 specimens was measured with a Vickers microhardness measuring instrument. Results: All tested GICs showed lower surface roughness values after the polishing procedure. Surface finish of nanofiller GIC was smoother than the other tested GICs after polishing. This was followed by resin-modified GIC, Fuji II LC; then silver-reinforced GIC, Argion Molar, conventional GICs, Aqua Ionofil Plus, Fuji IX, and Ionofil Molar, respectively. The result of the hardness test indicated that the microhardness value of silver-reinforced GIC was greater than that of the other GICs. When the hardness values of all tested GICs were compared, the differences between materials (except Aqua Ionofil Plus with Ionofil Molar and Ketac N100 with Fuji II LC (P>.05)) were found statistically significant (P<.05). Conclusions: According to the results of this study, it can be concluded that the differences in the composition of GICs may affect their surface roughness and hardness.

Bala, Oya; Arisu, Hacer Deniz; Yikilgan, Ihsan; Arslan, Seda; Gullu, Abdulkadir

2012-01-01

155

Clinical performance of Class II restorations in which resin composite is laminated over resin-modified glass-ionomer.  

PubMed

This study evaluated the one-year functioning of resin-composite/resin-modified glass-ionomer open-laminate restorations when used for restoring Class II cavities. It also investigated the effect of the thickness of the resin composite layer on the performance of such restorations. The test restorations were made of Vitremer glass ionomer, Scotchbond Multipurpose Plus and Z100 resin composite, and the control restorations were made of Z100 with Scotchbond Multipurpose Plus. Forty pairs of restorations were placed in 40 patients aged 16 years and over. The thickness of the resin composite layer was measured both clinically and in the laboratory using a reflex microscope. The completed restorations were assessed in vivo and in vitro at baseline, six-month and one-year recalls using a modified Ryge system. The reflex microscope measurements showed that the majority of restorations had a resin composite layer of more than 1.5 mm in thickness, as intended. At one year, 37 pairs of restorations were examined. Apart from a few minor problems, all performed satisfactorily. Thus, it appears that the resin composite/resin modified glass ionomer open laminate is a suitable technique for restoring Class II cavities. PMID:11203844

Aboush, Y E; Torabzadeh, H

156

Microleakage of newly developed glass carbomer cement in primary teeth  

PubMed Central

Objective: Glass carbomer cement represents a new generation of dental material, which mineralizes gradually into fluorapatite. The aim of this study was to evaluate the microleakage and marginal integrity of newly developed glass carbomer cement with and without protective surface coating (SC) in primary molars. Methods: Standardized cavities were prepared on extracted human primary molars, and the teeth were randomly assigned into the following groups (n = 10/each): (1) conventional glass ionomer cement (GIC) without SC; (2) GIC with SC; (3) glass carbomer cement without SC; (4) glass carbomer cement with SC; and (5) compomer without SC. Following thermocycling (5 ± 2°C–55 ± 2°C, dwell time 15 s, 2000×), the specimens were immersed in 0.5% basic fuchsin solution, sectioned, and digitally photographed. Microleakage was evaluated quantitatively by using open-source image analysis toolkit (ImageJ), and the data were analyzed statistically by using Kruskal-Wallis and Conover’s Multiple Comparison tests (P=.05). Results: The greatest amount of dye leakage was observed in the uncoated glass carbomer specimens, followed by the uncoated glass ionomer group (P<.05). There was no significant difference between the microleakage values of coated glass ionomer, coated glass carbomer, and the compomer (P>.05). The following statistical ranking was observed among microleakage of the test materials: uncoated glass carbomer > uncoated glass ionomer > coated glass ionomer ? coated glass carbomer ? compomer. Uncoated glass carbomer exhibited severe internal ice crack-like lines. Conclusion: The use of the new glass carbomer cement without SC results in severe microleakage and catastrophic internal cracks.

Cehreli, Sevi Burcak; Tirali, R. Ebru; Yalcinkaya, Zeynep; Cehreli, Zafer C.

2013-01-01

157

The uptake and release of fluoride by ion-leaching cements after exposure to toothpaste  

Microsoft Academic Search

Objectives: The cariostatic action associated with the glass-ionomer cement (GIC) is usually attributed to its sustained release of fluoride. However the ability of the GIC to act as a fluoride reservoir, taking it up from an external source (e.g. toothpaste, mouthwash) and subsequently releasing it over time, may also be a contributory factor. This study investigated the reservoir effect of

M Rothwell; H. M Anstice; G. J Pearson

1998-01-01

158

Comparison of the effect of storage media on shear punch strength of resin luting cements  

Microsoft Academic Search

ObjectivesTo measure the shear punch strength of eight resin-containing luting cements before and after immersion in acidic solution and ethanol at different temperatures (37°C and 60°C). Method: Specimens were prepared from six resin luting cements; Set (SDI), Panavia F (Kuraray), RelyX Veneer (3M\\/ESPE), VarioloinkII (Ivoclar), Maxcem (Kerr), Nexus2 (Kerr) and two Resin-modified glass-ionomer luting cements (RM-GICs); GC Fuji Plus (GC

Rafat Bagheri; Ay?e Mese; Michael F. Burrow; Martin J. Tyas

2010-01-01

159

Randomized clinical trial of two resin-modified glass ionomer materials: 1-year results.  

PubMed

With institutional review board approval, 33 patients who needed restoration of noncarious cervical lesions (NCCL) were enrolled in this study. A total of 92 NCCL were selected and randomly assigned to three groups: (1) Ambar (FGM), a two-step etch-and-rinse adhesive (control), combined with the nanofilled composite resin Filtek Supreme Plus (FSP; 3M ESPE); (2) Fuji II LC (GC America), a traditional resin-modified glass ionomer (RMGIC) restorative material; (3) Ketac Nano (3M ESPE), a nanofilled RMGIC restorative material. Restorations were evaluated at six months and one year using modified United States Public Health Service parameters. At six months after initial placement, 84 restorations (a 91.3% recall rate) were evaluated. At one year, 78 restorations (a 84.8% recall rate) were available for evaluation. The six month and one year overall retention rates were 93.1% and 92.6%, respectively, for Ambar/FSP; 100% and 100%, respectively, for Fuji II LC; and 100% and 100%, respectively, for Ketac Nano with no statistical difference between any pair of groups at each recall. Sensitivity to air decreased for all three adhesive materials from the preoperative to the postoperative stage, but the difference was not statistically significant. For Ambar/FSP, there were no statistical differences for any of the parameters from baseline to six months and from baseline to one year. For Fuji II LC, surface texture worsened significantly from baseline to six months and from baseline to one year. For Ketac Nano, enamel marginal staining increased significantly from baseline to one year and from six months to one year. Marginal adaptation was statistically worse at one year compared with baseline only for Ketac Nano. When parameters were compared for materials at each recall, Ketac Nano resulted in significantly worse color match than any of the other two materials at any evaluation period. At one year, Ketac Nano resulted in significantly worse marginal adaptation than the other two materials and worse marginal staining than Fuji II LC. Surface texture was statistically worse for Fuji II LC compared with the other two materials at all evaluation periods. The one-year retention rate was statistically similar for the three adhesive materials. Nevertheless, enamel marginal deficiencies and color mismatch were more prevalent for Ketac Nano. Surface texture of Fuji II LC restorations deteriorated quickly. PMID:22770485

Perdigão, J; Dutra-Corrêa, M; Saraceni, S H C; Ciaramicoli, M T; Kiyan, V H

2012-07-07

160

Influence of chemo-mechanical caries removal on the surface topography of dental composite resin and glass-ionomer materials: an in vitro study.  

PubMed

The aim of the present study was to investigate the influence of a chemo-mechanical caries removal system, Carisolv gel, on the surface topography of dental filling materials. Thirty specimens of a composite resin (Spectrum) and a compomer (Dyract AP) and 60 specimens of a glass-ionomer (Ketac-Fil Plus) were prepared. The surface topography was investigated with an optical interferometer before and after chemical exposure for 5, 10, or 20 min. Each specimen acted as its own control. The topographical part of the glass-ionomer materials was performed in two series with different drying procedures, since this material exhibits a higher sensitivity to dehydration than the other materials. The surface topographical investigations were complemented with contact angle measurements. After Carisolv gel exposure the density of summits and the developed surface area ratio (3D/2D) were slightly smaller for the composite resin and the compomer. For the minimally dried glass-ionomer material, the results indicated a reduction of the height of the surface structures, as well as a surface area enlargement, after Carisolv gel exposure. No statistically significant changes of contact angles due to Carisolv gel exposure could be detected for any material investigated. If dental filling materials of composite resin or glass-ionomer materials are exposed to Carisolv gel, no or only minor surface topographical changes can be expected. n PMID:15370632

Arvidsson, Anna; Ortengren, Ulf; Wennerberg, Ann

2004-06-01

161

Determination of the properties of an experimental glass polyalkenoate cement prepared from niobium silicate powder containing fluoride  

Microsoft Academic Search

ObjectivesThe purpose of this paper is to modify the conventional calcium fluoro-alumino-silicate glass, which is used in the formation of glass ionomer cements (CIGs) by the niobium addition and to study the properties of GICs obtained.

Márcio J. Bertolini; Maria A. Zaghete; Rossano Gimenes; Gislaine C. Padovani

2008-01-01

162

The role of glass composition in the behaviour of glass acetic acid and glass lactic acid cements.  

PubMed

Cements have recently been described, made from glass ionomer glass reacted with acetic and lactic acid instead of polymeric carboxylic acid. From their behaviour a theory relating to a possible secondary setting mechanism of glass ionomer has been adduced. However, only one glass (G338) was used throughout. In this study a much simpler glass ionomer glass (MP4) was compared with G338. This produced very different results. With acetic acid G338 formed cement which became resistant to water over a period of hours, as previously reported, MP4 formed cement which was never stable to water. With lactic acid G338 behaved similarly to G338 with acetic acid, again as reported, but MP4 produced a cement which was completely resistant to water at early exposure and unusually became slightly less resistant if exposure was delayed for 6 h or more. These findings indicate that the theories relating to secondary setting in glass ionomer maturation may need revision. PMID:17619992

Shahid, Saroash; Billington, R W; Pearson, G J

2007-07-10

163

Clinical attachment level gain and bone regeneration around a glass ionomer restoration on root surface wall of periodontal pocket  

PubMed Central

A case describing perio-restorative management of an accidental trauma in the mid portion of root on an upper left canine tooth following an ostectomy surgery is presented here. The traumatized root area was undergoing fast resorption and a chronic periodontal abscess had developed in relation to the lesion. The article illustrates the clinical and radiographic photo series of a periodontal flap surgery done to gain access into a subgingival region for the placement of Glass ionomer restoration on the root and its periodic follow up. The clinical condition of the area suggests 8 mm clinical attachment gain over the restoration and the review radiographs at definite intervals up to 18 months revealed evidence of consistent bone regeneration around the restoration. The article also highlights the various other possibilities, where this restorative material can be effectively used in conjunction with periodontal surgical procedures.

Biniraj, K. R.; Sagir, Mohammed; Sunil, M. M.; Janardhanan, Mahija

2012-01-01

164

Dentin-cement Interfacial Interaction: Calcium Silicates and Polyalkenoates  

Microsoft Academic Search

The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline caustic

A. R. Atmeh; E. Z. Chong; G. Richard; F. Festy; T. F. Watson

2012-01-01

165

Class II Amalgam Restorations, Glass-Ionomer Tunnel Restorations, and Caries Development on Adjacent Tooth Surfaces: A 3Year Clinical Study  

Microsoft Academic Search

Eighteen caries-active adolescents, each having both a class II conventional amalgam (Dispersalloy) and a glass-ionomer (Ketac Silver) tunnel restoration of the same age placed on a contralateral tooth, were part of a 3-year clinical study. At the 1- and 2-year examinations all test restorations were assessed as acceptable in all patients. At the 3-year assessment three amalgam restorations failed due

M. Svanberg

1992-01-01

166

Three-Year Survival of One-Surface ART Restorations and Glass-Ionomer Sealants in a School Oral Health Programme in Zimbabwe  

Microsoft Academic Search

An oral health care programme in secondary schools using the atraumatic restorative treatment (ART) approach for dental caries was started in 1993. Glass ionomer (restorative type II, 1) was used as the restorative and sealant material. Sealants were placed using the ‘press-finger’ technique. Results after 3 years revealed a survival percentage for one-surface ART restorations of 85.3 (95% CL: 89.7–80.9%),

J. E. Frencken; F. Makoni; W. D. Sithole; E. Hackenitz

1998-01-01

167

Long-term monitoring of microleakage of dental cements by radiochemical diffusion  

SciTech Connect

Radioactive /sup 14/C sucrose was found to be an ideal marker for microleakage because it did not penetrate tooth tissue, dental cement, or mounting resin. The main finding is that the adhesive cements--the glass-ionomer and polycarboxylate--are significantly more effective at preventing microleakage than are the traditional phosphate cements--silicate and zinc phosphate. The differences can be as high as two orders of magnitude. The adhesive cements provide almost perfect and reliable seals. By contrast, the nonadhesive cements are erratic sealants with most of the restorations leaking.

Powis, D.R.; Prosser, H.J.; Wilson, A.D.

1988-06-01

168

Comparison of Shear Bond Strength of Resin-Modified Glass Ionomer and Composite Resin to Three Pulp Capping Agents  

PubMed Central

Background and aims. Present study was designed to compare the bonding strength of resin-modified glass ionomer (RMGI) and composite resin to mineral trioxide aggregate (MTA), MTA mixed with Na2HPO4 (NAMTA), and calcium-enriched mixture (CEM). Materials and methods. Thirty specimens of each CEM, NAMTA, and MTA were prepared. Composite and RMGI restorations were then placed on the samples (15 samples in six subgroups). Shear bond strength was assessed using universal testing machine. Data were analyzed with two-way ANOVA and post-hoc Tukey test. To compare the bond strength in subgroups, one-away ANOVA was applied. Significance level was set at P < 0.05. Results. Bond strength was significantly higher to composite samples compared to RMGI samples (p<0.001). The difference in bond strength of composite samples between MTA and CEM subgroups (P=0.026) as well as MTA and NAMTA subgroups (P= 0.019) was significant, but the difference between NAMTA and CEM subgroups (P=0.56) was not significant. The differences in bond strength in subgroups of RMGI group were not significant (P>0.05). Conclusion. Regarding shear bond strength to the tested substrates, composite was shown to be superior to RMGI. The bond of resin composite to MTA was weaker than that to CEM and NAMTA.

Ajami, Amir Ahmad; Jafari Navimipour, Elmira; Savadi Oskoee, Siavash; Abed Kahnamoui, Mehdi; Lotfi, Mehrdad; Daneshpooy, Mehdi

2013-01-01

169

Preparation of glass ionomer cement using N-acryloyl-substituted amino acid monomers — Evaluation of physical properties  

Microsoft Academic Search

Objectives. The objectives of this study were (1) to develop polyacid formulations through the incorporation of amino acid-derived monomers with carboxylic acid groups at various distances away from the polymer backbone to allow for greater flexibility, less rigid ionic cluster formation and improved solubility, and (2) to test selected physical and handling properties of experimental ionomers with a conventional glass

Elizabeth C. Kao; Bill M. Culbertson; Dong Xie

1996-01-01

170

[Influence of types and surface treatment of dental alloy and film thickness of cements on bond strength of dental luting cements].  

PubMed

The goal of this study was to test the influence of the type and oxidation treatment of dental casting alloys on the tensile bond strength of luting cements. Also, the influence of film thickness of luting cements on the tensile bond strength of different dental casting alloys was examined. Four different luting cements (zinc phosphate, polycarboxylate, glass ionomer and adhesive resin cements) and four different dental casting alloys (Au-Ag-Cu, Ag-Pd, hardened Ag-Pd and Ni-Cr alloys) were used. Cylindrical alloy rods for the tensile bond strength test were casted, and then, top surfaces of the rods were cemented with each luting cement to the bottom surfaces of other rods, using the film thickness adjustment apparatus. The film thickness of luting cement was adjusted to 20, 30, 50, 75 or 100 microns. The tensile bond strengths of each cement to different casting alloys at each film thickness were measured one day after the rods had been cemented. The tensile bond strength of the zinc phosphate cement could not be determined in this study due to the separation of the alloy rods cemented with the zinc phosphate cement in water before the tensile test. The tensile bond strength to the adhesive resin cement to any alloy showed the greatest strength; however, that of the glass ionomer cement to any alloy was the lowest strength among the cements examined. The Ni-Cr alloy had the highest bond strength of any luting cement, compared to other alloys. The tensile bond strengths of luting cements significantly decreased with the increase in film thickness of cement layer. The adhesive resin cement had the greatest bond strength, and the glass ionomer cement was the lowest bond strength at any film thickness. The oxidation treatment significantly increased the bond strength of the adhesive resin cement to both Au-Ag-Cu and Ag-Pd alloys. The tensile bond strength of the adhesive resin cement was most dependent upon the film thickness of cement layer, and that of the polycarboxylate cement was least dependent upon the film thickness of cement layer among the cements examined. In addition, the oxidation treatment for precious alloys could be a factor contributing to the increase in the bond strength of the adhesive resin cement. PMID:2135542

Hibino, Y

1990-11-01

171

The three-dimensional effects of adjustment and cementation on crown seating.  

PubMed

This study investigated the three-dimensional nature of crown fit and the effects of adjustment and luting. Standardized preparations were made on extracted premolars and impressions and dies made. Complete-coverage castings were fabricated using base metal alloy. The castings were placed on their respective teeth and measurements made. The castings were then adjusted using a silicone disclosing medium and remeasured. They were then assigned to one of five luting agent groups and cemented. A relative term describing tilting was defined. Casting adjustment decreased tilting and cementation increased tilting. Resin cements tilted castings significantly more than did zinc phosphate, glass-ionomer, or polycarboxylate cements. PMID:8397692

White, S N; Kipnis, V

172

Maximum bond strength of dental luting cement to amalgam alloy.  

PubMed

Although dental amalgam is used frequently under artificial crowns for restoration of severely damaged teeth, there is little information available on the bond between luting cements and this alloy. This study was designed for determination of the strength of the bond between a dental amalgam alloy and three crown-luting cements. Cylinders of dental amalgam were joined in pairs, with use of a zinc-phosphate, a glass-ionomer, and an acrylic-adhesive resin cement. The tensile-fracture stress of 45 samples of each cement was measured with a universal testing machine, and subjected to a Weibull analysis. The fractured surfaces were examined under low magnification with use of a light microscope, and at low and high magnifications with use of a scanning electron microscope, for evaluation of the appearance of the fractured joints. The Weibull analysis demonstrated that the adhesive resin cement provided a stronger and more predictable bond than either the zinc-phosphate or the glass-ionomer cement. The appearance of the fractured surfaces gave no indication of the strength of the joints, a feature that is common to brittle materials. The results suggest that crowns placed on teeth offering a large amalgam-alloy surface could be retained more predictably with an adhesive resin cement. PMID:2685070

Mojon, P; Hawbolt, E B; MacEntee, M I; Belser, U C

1989-11-01

173

Bioactive glass incorporation in calcium phosphate cement-based injectable bone substitute for improved in vitro biocompatibility and in vivo bone regeneration.  

PubMed

In this work, we fabricated injectable bone substitutes modified with the addition of bioactive glass powders synthesized via ultrasonic energy-assisted hydrothermal method to the calcium phosphate-based bone cement to improve its biocompatibility. The injectable bone substitutes was initially composed of a powder component (tetracalcium phosphate, dicalcium phosphate dihydrate and calcium sulfate dehydrate) and a liquid component (citric acid, chitosan and hydroxyl-propyl-methyl-cellulose) upon which various concentrations of bioactive glass were added: 0%, 10%, 20% and 30%. Setting time and compressive strength of the injectable bone substitutes were evaluated and observed to improve with the increase of bioactive glass content. Surface morphologies were observed via scanning electron microscope before and after submersion of the samples to simulated body fluid and increase in apatite formation was detected using x-ray diffraction machine. In vitro biocompatibility of the injectable bone substitutes was observed to improve with the addition of bioactive glass as the proliferation/adhesion behavior of cells on the material increased. Human gene markers were successfully expressed using real time-polymerase chain reaction and the samples were found to promote cell viability and be more biocompatible as the concentration of bioactive glass increases. In vivo biocompatibility of the samples containing 0% and 30% bioactive glass were evaluated using Micro-CT and histological staining after 3 months of implantation in male rabbits' femurs. No inflammatory reaction was observed and significant bone formation was promoted by the addition of bioactive glass to the injectable bone substitute system. PMID:23470354

Sadiasa, Alexander; Sarkar, Swapan Kumar; Franco, Rose Ann; Min, Young Ki; Lee, Byong Taek

2013-03-01

174

Determination of the properties of an experimental glass polyalkenoate cement prepared from niobium silicate powder containing fluoride  

Microsoft Academic Search

Objectives. The purpose of this paper is to modify the conventional calcium fluoro-alumino- silicate glass, which is used in the formation of glass ionomer cements (CIGs) by the niobium addition and to study the properties of GICs obtained. Materials and methods. Sol-gel process was used to prepare the powder at lower temperature than fusion method. Glass-ceramic powder obtained in this

J. Bertolini; Maria A. Zaghete; Rossano Gimenes; Gislaine C. Padovani

175

Combination Flap Surgery with Resin-Modified Glass Ionomer for the Treatment of Radicular Lesions: A Long-Term Follow-up.  

PubMed

This retrospective study evaluated the long-term clinical success of combination therapy using resin-modified glass ionomer (RMGI) with flap surgery in treating subgingival radicular defects. The study population consisted of 142 patients with 188 radicular defects. Clinical parameters (pocket depth, recession, clinical attachment level [CAL], and bleeding on probing) were evaluated. Statistically significant CAL gain was observed from baseline to follow-up in successful cases (4.3 ± 0.1 mm to 4.1 ± 0.1 mm, respectively; P < .01). RMGI with flap surgery demonstrated an overall success rate of 86.7% (77.7% with open flap debridement and 94.4% with coronally advanced flap with or without connective tissue graft), with favorable and stable clinical results over a mean period of 4.2 years (longest follow-up, 13 years). PMID:24116366

Perez, Luis A; Lee, Angie; Medina, Gioconda; Eber, Robert; Wang, Hom-Lay; Oh, Tae-Ju

176

Shear bond strength of acidic primer, light-cure glass ionomer, light-cure and self cure composite adhesive systems - an in vitro study.  

PubMed

Background: The purpose of this study was to determine shear bond strength and the effect on the bracket/ adhesive failure mode when an acidic primer and other etchants were used to condition the enamel surface before bonding. Materials & Methods: Group I: Brackets bonded with Ultimate cure-on-light Light-cure composite adhesive system. Group II: Brackets bonded with Ortho-one no-mix. Self-cure composite adhesive system. Group III: Brackets bonded with Light-cure glass ionomer adhesive system. Group IV: Brackets bonded with Transbond plus self etching primer. Results: The results of this study indicated that the shear bond strength when using Transbond plus self etching primer showed the highest bond strength Group- IV(8.69 2.54 MPa) followed by Ultimate cure-on-light Group-I (8.62 1.84 MPa), Ortho-one no-mix (Bisco Inc. USA)Group-II (8.07 1.72 MPa), and least bond strength was seen in G.C. Fuji Ortho L.C. Group-III (6.01 1.6) MPa Conclusion: Use of self etching primer saves chairside time and satisfactory high bond strength was obtained. Care should be taken during debonding of ceramic brackets How to cite this article: Reddy K D, Kishore M S V, Safeena S. Shear Bond Strength of Acidic Primer, Light-Cure Glass Ionomer, Light-Cure and Self Cure Composite Adhesive Systems - An In Vitro Study. J Int Oral Health 2013; 5(3):73-78. PMID:24155606

D, Krishnakanth Reddy; V, Kishore M S; Safeena, Safeena

2013-06-23

177

Shear Bond Strength of Acidic Primer, Light-Cure Glass Ionomer, Light-Cure and Self Cure Composite Adhesive Systems - An In Vitro Study  

PubMed Central

Background: The purpose of this study was to determine shear bond strength and the effect on the bracket/ adhesive failure mode when an acidic primer and other etchants were used to condition the enamel surface before bonding. Materials & Methods: Group I: Brackets bonded with Ultimate cure-on-light Light-cure composite adhesive system. Group II: Brackets bonded with Ortho-one no-mix. Self-cure composite adhesive system. Group III: Brackets bonded with Light-cure glass ionomer adhesive system. Group IV: Brackets bonded with Transbond plus self etching primer. Results: The results of this study indicated that the shear bond strength when using Transbond plus self etching primer showed the highest bond strength Group- IV(8.69 2.54 MPa) followed by Ultimate cure-on-light Group-I (8.62 1.84 MPa), Ortho-one no-mix (Bisco Inc. USA)Group-II (8.07 1.72 MPa), and least bond strength was seen in G.C. Fuji Ortho L.C. Group-III (6.01 1.6) MPa Conclusion: Use of self etching primer saves chairside time and satisfactory high bond strength was obtained. Care should be taken during debonding of ceramic brackets How to cite this article: Reddy K D, Kishore M S V, Safeena S. Shear Bond Strength of Acidic Primer, Light-Cure Glass Ionomer, Light-Cure and Self Cure Composite Adhesive Systems - An In Vitro Study. J Int Oral Health 2013; 5(3):73-78.

D, Krishnakanth Reddy; V, Kishore M S; Safeena, Safeena

2013-01-01

178

[Bond strength of dental luting cements to titanium castings].  

PubMed

This study compared the tensile bond strength of dental luting cements to the titanium castings with gold alloy (Type IV), 12% Au-Ag-Pd alloy and Ni-Cr alloy in dental clinical practice. In this experimental condition, the zinc phosphate cement did not adhere to any dental casting alloy tested. The tensile bond strength of polycarboxylate cement to the titanium castings was 96 kg/cm2, about two times as high as that gold alloy (Type IV). The tensile bond strength of the glass ionomer cement to titanium castings was 32 kg/cm2, about two times as high as that of dental precious alloys. The tensile bond strength of the adhesive resin cement to titanium castings was 220 kg/cm2, about three times as high as that of dental precious alloys. PMID:2134816

Hibino, Y; Kuroiwa, A; Kurosawa, S; Kanke, S; Hashimoto, H

1990-01-01

179

Radiographic appearance of commonly used cements in implant dentistry.  

PubMed

Cement-retained restorations allow for a conventional fixed partial denture approach to restoring dental implants. However, inadequate removal of excess cement at the time of cementation may introduce a severe complication: cement-induced peri-implantitis. Radiopaque cements are more easily detected on radiographs and should improve the recognition of extravasated cement at the time of insertion. The purpose of this study was to evaluate the radiopacity of commercially available cements in vitro. Eighteen different cements commonly used for luting restorations to implants were tested at both 0.5- and 1.0-mm thicknesses. The cements examined were zinc oxide eugenol, zinc oxide, zinc polycarboxylate, zinc phosphate, resin-reinforced glass ionomer, urethane resin, resin, and composite resin. Two samples of each cement thickness underwent standardized radiography next to an aluminum step wedge as a reference. The mean grayscale value of each of the nine 1-mm steps in the step wedge were used as reference values and compared to each of the cement samples. Temp Bond Clear (resin), IMProv (urethane resin), Premier Implant Cement (resin), and Temrex NE (resin) were not radiographically detectable at either sample thickness. Cements containing zinc were the most detectable upon radiographic analysis. There are significant differences in the radiopacity of many commonly used cements. Since cementinduced peri-implantitis can lead to late implant failure, cements that can be visualized radiographically may reduce the incidence of this problem. PMID:23342348

Pette, Gregory A; Ganeles, Jeffrey; Norkin, Frederic J

180

Quantification of all-ceramic crown margin surface profile from try-in to 1-week post-cementation  

Microsoft Academic Search

ObjectivesTo use profilometry to assess the margin surface profile of all-ceramic crowns (ACC’s) at try-in and 1-week after cementation with dual-cured resin (DC, RelyX ARC, 3M ESPE, St. Paul, MN, USA), self-adhesive dual-cured resin (SADC, RelyX Unicem, 3M ESPE), light-cured resin (LC, RelyX Veneer, 3M ESPE) or chemically cured resin-modified glass ionomer (RMGI, RelyX Luting Plus, 3M ESPE) luting cement.

Melissa-L. Good; Christina A. Mitchell; Maria R. Pintado; William H. Douglas

2009-01-01

181

Comparison of the Shear Bond Strength of Resin Modified Glass Ionomer to Enamel in Bur-Prepared or Lased Teeth (Er:YAG)  

PubMed Central

Objective: The purpose of this study was to evaluate the effect of Er:YAG laser on the shear bond strength of resin modified glass ionomer (RMGI) to enamel. Materials and Methods: Twenty extracted caries-free human premolars were selected. The teeth were embedded in acrylic resin. The buccal surfaces of each sample were ground to plane enamel with carbonated disc. The teeth were randomly divided in two groups. In the first group, the surfaces were treated by Er:YAG laser (350mJ/10Hz). The second group was prepared by carbide bur. Fuji IX RMGI was adhered to surfaces of the samples in both groups in rod shape. The shear bond strength of samples was measured by a universal testing machine. The results of the two groups were analyzed by T- test. Results: The means and standard deviations of shear bond strength of the laser-treated group and the bur-treated group were 6.75 ± 1.99 and 4.41 ± 1.62 Mpa, respectively. There is significant difference in the shear bond strength of RMGI between the two groups (P-value=0.01). Conclusion: The laser group showed better results. Er:YAG laser can be an alternative technology in restorative dentistry.

Jafari, Ahmad; Shahabi, Sima; Chiniforush, Nasim; Shariat, Ali

2013-01-01

182

Effect of light-cure initiation time on polymerization and orthodontic bond strength with a resin-modified glass-ionomer  

NASA Astrophysics Data System (ADS)

Introduction: The polymerization and acid-base reactions in resin-modified glass-ionomers (RMGI) are thought to compete with and inhibit one another. The objective of this study was to examine the effect of visible light-cure (VLC) delay on the polymerization efficiency and orthodontic bond strength of a dual-cured RMGI. Methods: An RMGI light-cured immediately, 2.5, 5, or 10 minutes after mixing comprised the experimental groups. Isothermal and dynamic temperature scan differential scanning calorimetry (DSC) analysis of the RMGI was performed to determine extents of VLC polymerization and acid-base reaction exotherms. Human premolars (n = 18/group) were bonded with the RMGI. Shear bond strength and adhesive remnant index (ARI) scores were determined. Results: DSC results showed the 10 minute delay RMGI group experienced significantly (P <0.05) lower VLC polymerization compared to the other groups. Acid-base reaction exotherms were undetected in all groups except the 10 minute delay group. No significant differences (P >0.05) were noted among the groups for mean shear bond strength. A chi-square test showed no significant difference (P = 0.428) in ARI scores between groups. Conclusions: Delay in light-curing may reduce polymerization efficiency and alter the structure of the RMGI, but orthodontic shear bond strength does not appear to be compromised.

Thomas, Jess

183

Effect of the CO2 laser on the microleakage of conventional and laser apicetomized teeth retrofilled with glass ionomer: in vitro study  

NASA Astrophysics Data System (ADS)

There is a need for further improvement on the level of apical sealing. The use of lasers on apical surgery is still not fully understood, however some good results have been reported. The aim of this study was to assess the effect of the use of the CO2 laser following conventional apicoectomy and retrofilling with glass ionomer using different combinations of power and types of emission 'In Vitro.' Seventy extracted human upper anterior teeth were used on this study. The teeth after conventional apicoectomy were retrofilled with VitremerTM. The samples were randomized into seven groups of 10, Group I acted as negative control. Groups II, III and IV were lased on defocused mode with superpulsed CO2 laser on CW with power output of 0,5; 3 and 7 Watts during 5 seconds respectively. Groups V, VI e VII were lased on defocused mode with continuous emission on CW mode with power output of 1, 10 and 20 Watts during 5 seconds respectively. All specimens were immersed on 2% Methylene Blue solution during 48 h, washed in running tap water and longitudinally sectioned. Three calibrated examiners regarding apical infiltration graded the samples. The results showed difference between groups, where Group II showed smaller level of apical infiltration. It is concluded that improving on apical sealing is better achieved by using 0.5 W on superpulsed on CW.

Pinheiro, Antonio L.; Martorelli, Sergio B.

2000-03-01

184

Comparison of a SiO2-CaO-ZnO-SrO glass polyalkenoate cement to commercial dental materials: ion release, biocompatibility and antibacterial properties.  

PubMed

Ion Release and biocompatibility of a CaO-SrO-ZnO-SiO2 (BT 101) based glass polyalkenoate cement (GPC) was compared against commercial GPCs, Fuji IX and Ketac Molar. The radiopacity (R) was similar for each material, 2.0-2.8. Ion release was evaluated on each material over 1, 7, 30 and 90 days. BT 101 release included Ca (23 mg/L), Sr (23 mg/L) Zn (13 mg/L), Si (203 mg/L). Fuji IX release includes Ca (0.7 mg/L), Al (3 mg/L) Si (26 mg/L), Na (60 mg/L) and P (0.5 mg/L) while Ketac Molar release includes Ca (1 mg/L), Al (0.6 mg/L) Si (23 mg/L), Na (76 mg/L) and P (0.7 mg/L). Simulated body fluid trials revealed CaP surface precipitation on BT 101. No evidence of precipitation was found on Fuji IX or Ketac Molar. Cytotoxicity testing found similar cell viability values for each material (~60 %, P = 1.000). Antibacterial testing determined a reduced CFU count with BT 101 (2.5 × 10(3)) when compared to the control bacteria (2.4 × 10(4)), Fuji IX (1.5 × 10(4)) and Ketac Molar (1.2 × 10(4)). PMID:23793491

Wren, A W; Coughlan, A; Hall, M M; German, M J; Towler, M R

2013-06-21

185

Effect of Different Luting Cements on Fracture Resistance in Endodontically Treated Teeth  

PubMed Central

INTRODUCTION: The aim of the present study was to evaluate the effect of three types of luting cements used for post cementation on the fracture resistance of endodontically treated maxillary premolars, restored with resin composite. MATERIALS AND METHODS: One hundred intact single-rooted human maxillary premolars were randomly divided into 5 groups of 20 each. In groups 2-5, post spaces were prepared after root canal treatment and clinical crown reduction up to 1.5 mm above the CEJ. Teeth were divided in groups as follows: Group 1: intact teeth, Group 2: active prefabricated metallic posts (PMP), Group 3: PMP cemented with zinc phosphate luting cement, Group 4: PMP cemented with glass ionomer luting cement and Group 5: PMP cemented with resin luting cement. In groups 2-5 the teeth were restored with resin composite. Following thermocycling, the palatal cusp of each specimen was loaded to compression at an angle of 150? to its longitudinal axis at a strain rate of 2 mm/min until fracture occurred. Data were analyzed using one-way ANOVA and a post hoc Tukey test. Chi-square test was used for comparison of failure mode. RESULTS: There were significant differences in fracture resistance between the test groups (P<0.001). The differences between group 2 with groups 1, 4 and 5 were statistically significant (P<0.05); whereas there were no significant differences in fracture resistance between the two other groups (P>0.05). Furthermore, there were no significant differences in the mode of failure between the 5 groups (P>0.05). CONCLUSION: Zinc phosphate, glass ionomer and resin luting cements showed similar behaviors and achieved fracture resistance comparable to intact teeth. However, the use of active post (without cement) adversely affected the fracture resistance of root canal treated teeth.

Mohammadi, Narmin; Ajami, Amir Ahmad; Kimyai, Soodabeh; Rezaei Aval, Mojdeh

2008-01-01

186

Effect of acid pre-conditioning and/or delayed light irradiation on enamel bond strength of three resin-modified glass ionomers  

PubMed Central

Background: Polymerization of resin-modified glass-ionomers (RMGIs) is mediated through two competing mechanisms: An acid-base reaction and a light-dependent resin polymerization. Furthermore, pre-conditioning with acid has resulted in an increase in enamel bond strength of some RMGIs. This in vitro study evaluated the effect of pre-conditioning and/or delayed irradiation on bond strength of three RMGIs to enamel. Materials and Methods: In this in vitro study, 144 flat enamel surfaces of human molars were ground using consecutively finer abrasives up to 600-grit silicon carbide paper. Each surface was rinsed and gently air-dried (n =12). The RMGIs (Fuji II LC Improved; Ionolux and Vitremer) were bonded to enamel surfaces using the following protocols: Groups 1: Based on manufacturers’ instructions; Groups 2: Pre-conditioning with phosphoric acid for 30 s; groups 3: A 2-min delay in irradiation; groups 4: Pre-conditioning with acid for 30 s plus a 2-min delay in light activation. After 24-h storage at 37°C and 500 rounds of thermocycling, the samples underwent shear bond strength (SBS) test. Data was analyzed with 3-way ANOVA and Tukey HSD test (? =0.05). Results: There were significant differences between the study groups (P < 0.001). Acid-pre-conditioning increased Fuji II LC SBS values; it significantly decreased SBS values of Vitremer but had no effect on SBS values of Ionolux. Ionolux and Vitremer exhibited decreased enamel bond strength after a delay in light activation (P < 0.05). A 2-min delay in light activation combined with acid pre-conditioning increased RMGI SBS values only for Fuji II LC. Conclusion: Within the limitations of the present study, the effect of acid pre-conditioning, delaying irradiation and both on enamel bond strength of RMGIs was material-dependent. Further investigations are recommended.

Khoroushi, Maryam; Hosseini-Shirazi, Moeen; Soleimani, Hojatolah

2013-01-01

187

Clinical evaluation of giomer- and resin-modified glass ionomer cement in class V noncarious cervical lesions: An in vivo study  

PubMed Central

Objectives: To evaluate and compare the clinical performance of Giomer (Beautifil II) and RMGIC (Fuji II LC) in noncarious cervical lesions. Materials and Methods: Thirty-two subjects with one or two pairs of noncarious cervical lesions were included in the study. Each pair of lesion was restored with either giomer or RMGIC assigned randomly. Clinical evaluation of restorations was done using USPHS criteria. Data was formulated in a predesigned format and subjected to statistical analysis using the chi square test. Results: Statistically significant difference was found between RMGIC and Giomer with respect to surface roughness with P value <0.001. Conclusion: Giomer showed superior surface finish compared to RMGIC. Both Giomer and RMGIC showed equal retention ability.

Jyothi, KN; Annapurna, S; Kumar, Anil S; Venugopal, P; Jayashankara, CM

2011-01-01

188

Leakage associated with intermediate restorative material and glass-ionomer cement retrograde fillings: A human and sheep teeth comparison with 2 different aging procedures  

Microsoft Academic Search

Objectives: Leakage around retrograde fillings is an important cause of endodontic surgery. This in vitro study sought to compare the following: (1) methylene blue dye leakage linked to retrofillings in human and sheep teeth with the degree of dye penetration when intermediate restorative materials and Chemfil were used as retrofillings, (2) the apical microleakage in filled with that in unfilled

Dominique Roux; Sophie Doméjean-Orliaguet; Marwan Saade

2002-01-01

189

Evaluation of mechanical properties of five cements for orthodontic band cementation.  

PubMed

The aim of this in vitro study was to compare the flexural, compressive and diametral tensile strengths of five cements used in orthodontics for band cementation. Twelve specimens of each cement were tested: 1 - GC Fuji Ortho Band (FJ), GC America Inc.; 2 - Meron (MR), Voco; 3 - Multi-Cure Glass Ionomer Band Cement (MC), 3M Unitek; 4 - Band-Lok (BL), Reliance Orthodontic Products; and 5 - Ketac Cem (KC), 3M ESPE. The results (mean) for diametral tensile strength were: 10.51 MPa (FJ), 9.60 MPa (MR), 20.04 MPa (MC), 42.80 MPa (BL), and 4.08 MPa (KC). The results for compressive strength were (in the same order): 64.50 MPa, 77.71 MPa, 94.21 MPa, 193.88 MPa, and 81.93 MPa. The results for flexural strength were (in the same order): 20.72 MPa, 25.84 MPa, 53.41 MPa, 137.41 MPa, and 20.50 MPa. The statistical analysis was performed by two-way ANOVA and Tukey tests with p-value £ 0.05. In terms of diametral tensile strength, BL showed the highest strength statistically, and MC, the second highest. In terms of compressive tensile strength, BL showed the highest strength statistically, and FJ did not attain the minimum recommended strength. In terms of flexural tensile strength, BL cement was superior to MC, and MR, FJ and KC were equivalent and inferior to BL and MC. PMID:23459769

Aguiar, Diego Andrei; Ritter, Daltro Enéas; Rocha, Roberto; Locks, Arno; Borgatto, Adriano Ferreti

2013-03-01

190

Effect of a calcium-silicate-based restorative cement on pulp repair.  

PubMed

In cases of pulp injury, capping materials are used to enhance tertiary dentin formation; Ca(OH)(2) and MTA are the current gold standards. The aim of this study was to evaluate the capacity of a new calcium-silicate-based restorative cement to induce pulp healing in a rat pulp injury model. For that purpose, cavities with mechanical pulp exposure were prepared on maxillary first molars of 27 six-week-old male rats, and damaged pulps were capped with either the new calcium-silicate-based restorative cement (Biodentine), MTA, or Ca(OH)(2). Cavities were sealed with glass-ionomer cement, and the repair process was assessed at several time-points. At day 7, our results showed that both the evaluated cement and MTA induced cell proliferation and formation of mineralization foci, which were strongly positive for osteopontin. At longer time-points, we observed the formation of a homogeneous dentin bridge at the injury site, secreted by cells displaying an odontoblastic phenotype. In contrast, the reparative tissue induced by Ca(OH)(2) showed porous organization, suggesting a reparative process different from those induced by calcium silicate cements. Analysis of these data suggests that the evaluated cement can be used for direct pulp-capping. PMID:22983409

Tran, X V; Gorin, C; Willig, C; Baroukh, B; Pellat, B; Decup, F; Opsahl Vital, S; Chaussain, C; Boukpessi, T

2012-09-13

191

A study of cements formed by aqueous lactic acid and aluminosilicate glass.  

PubMed

A study is reported of the formation of cements from aqueous lactic acid and aluminosilicate glass of the type used in dental glass-ionomer cements. These cements were found to set quickly, and were shown by infrared spectroscopy to have undergone a neutralization reaction to yield mainly calcium lactate. They were very soluble in water at 1 h, but became progressively less so over time; when matured for 6 h before being placed in water, they had become almost insoluble. No spectroscopic differences could be detected between the cements at 1 h or 6 h, indicating that insolubilization arises from a reaction that does not alter the part of the infrared spectrum examined. This suggested that a wholly inorganic reaction between the ion-depleted glass fragments is responsible for the formation of the insoluble structure. After 24 h, the cements were found to have compressive strengths in the range 9-35 MPa, the actual value varying with concentration of lactic acid used to form the cement, and there was no statistically significant increase in strength for the strongest of these after one month. PMID:15348618

Nicholson, John W; Tawfik, Hamsa; Czarnecka, Beata

2002-04-01

192

Dentin-cement interfacial interaction: calcium silicates and polyalkenoates.  

PubMed

The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the "mineral infiltration zone", where the alkaline caustic effect of the calcium silicate cement's hydration products degrades the collagenous component of the interfacial dentin. This degradation leads to the formation of a porous structure which facilitates the permeation of high concentrations of Ca(2+), OH(-), and CO(3) (2-) ions, leading to increased mineralization in this region. Comparison of the dentin-restorative interfaces shows that there is a dentin-mineral infiltration with the Biodentine, whereas polyacrylic and tartaric acids and their salts characterize the penetration of the GIC. A new type of interfacial interaction, "the mineral infiltration zone", is suggested for these calcium-silicate-based cements. PMID:22436906

Atmeh, A R; Chong, E Z; Richard, G; Festy, F; Watson, T F

2012-03-20

193

Zinc polycarboxylate dental cement for the controlled release of an active organic substance: proof of concept.  

PubMed

The potential of employing zinc polycarboxylate dental cement as a controlled release material has been studied. Benzalkonium chloride was used as the active ingredient, and incorporated at concentrations of 1, 2 and 3% by mass within the cement. At these levels, there was no observable effect on the speed of setting. Release was followed using an ion-selective electrode to determine changes in chloride ion concentration with time. This technique showed that the additive was released when the cured cement was placed in water, with release occurring by a diffusion mechanism for the first 3 h, but continuing beyond that for up to 1 week. Diffusion coefficients were in the range 5.62 x 10(-6) cm(2) s(-1) (for 1% concentration) to 10.90 x 10(-6) cm(2) s(-1) (for 3% concentration). Up to 3% of the total loading of benzalkonium chloride was released from the zinc polycarboxylate after a week, which is similar to that found in previous studies with glass-ionomer cement. It is concluded that zinc polycarboxylate cement is capable of acting as a useful material for the controlled release of active organic compounds. PMID:19967407

Ali, Mohammad Naseem; Edwards, Mark; Nicholson, John W

2009-12-06

194

Evaluation of the caries-preventive effect of three orthodontic band cements in terms of fluoride release, retentiveness, and microleakage.  

PubMed

This in vitro study was undertaken to evaluate the caries-preventive effect of three orthodontic band cements (a dual-curing resinmodified glass ionomer cement [RMGIC] and two light-curing polyacid-modified composite resin [compomer] cements) in terms of fluoride release, retentiveness, and microleakage after thermocycling. The RMGIC (Ortholy Band Paste [GC Ortholy, Inc., Tokyo, Japan]) showed a significantly higher amount of cumulative fluoride release over 180 days (p<0.001) and significantly greater tensile bond strength (p<0.001) than the compomer cements (Transbond Plus [3M Unitek, Monrovia, CA, USA] and Ultra Band-Lok [Reliance Orthodontic Products, Inc., Itasca, IL, USA]). Its bond strength was unaffected by thermocycling (2,000 cycles), indicating good retentiveness, whereas that of the compomer cements significantly decreased after thermocycling. Moreover, it had lower dyepenetration scores, indicative of less microleakage. These findings suggest that the RMGIC may have a better caries-preventive effect than the compomer cements and is suitable for long-term orthodontic banding. PMID:23718996

Shimazu, Kisaki; Ogata, Kiyokazu; Karibe, Hiroyuki

2013-01-01

195

Carboxymethylation of ulvan and chitosan and their use as polymeric components of bone cements.  

PubMed

Ulvan, extracted from the green algae Ulva lactuca, and chitosan, extracted from Loligo forbesis squid-pen, were carboxymethylated, yielding polysaccharides with an average degree of substitution of ?98% (carboxymethyl ulvan, CMU) and ?87% (carboxymethyl chitosan, N,O-CMC). The carboxymethylation was confirmed by Fourier transform infrared spectroscopy and quantified by conductimetric titration and (1)H nuclear magnetic resonance. The average molecular weight increased with the carboxymethylation (chitosan, Mn 145?296kDa and Mw 227?416kDa; ulvan, Mn 139?261kDa and Mw 368?640kDa), indicating successful chemical modifications. Mixtures of the modified polysaccharides were tested in the formulation of polyacrylic acid-free glass-ionomer bone cements. Mechanical and in vitro bioactivity tests indicate that the inclusion of CMU in the cement formulation, i.e. 0.50:0.50N,O-CMC:CMU, enhances its mechanical performance (compressive strength 52.4±8.0MPa and modulus 2.3±0.3GPa), generates non-cytotoxic cements and induces the diffusion of Ca and/or P-based moieties from the surface to the bulk of the cements. PMID:23816652

Barros, A A A; Alves, A; Nunes, C; Coimbra, M A; Pires, R A; Reis, R L

2013-06-29

196

A bioactive dental luting cement--its retentive properties and 3-year clinical findings.  

PubMed

A clinical validation study was conducted to determine the performance of a new bioactive dental cement (Ceramir C&B, Doxa Dental AB) for permanent cementation. The cement is a new formulation class, which is a hybrid material comprised of calcium aluminate and glass-ionomer components. A total of 38 crowns and bridges were cemented in 17 patients; 31 of the abutment teeth were vital and seven were non-vital. Six restorations were bridges with a total of 14 abutment teeth (12 vital/ two non-vital). One fixed splint comprising two abutment teeth was also included. Preparation parameters were recorded, as well as cement characteristics such as working time, setting time, seating characteristics, and ease of cement removal. Baseline data were recorded for the handling of the cement, gingival inflammation, and pre-cementation sensitivity. Post-cementation parameters included post-cementation sensitivity, gingival tissue reaction, marginal integrity, and discoloration. All patients were seen for recall examinations at 30 days and 6 months. Fifteen of 17 subjects and 13 of 17 patients were also available for subsequent comprehensive 1- and 2-year recall examination, and 13 patients were available for a 3-year recall examination. Restorations available for the 3-year recall examination included 14 single-unit full-coverage crown restorations, four three-unit bridges comprising eight abutments, and one two-unit splint. Three-year recall data yielded no loss of retention, no secondary caries, no marginal discolorations, and no subjective sensitivity. All restorations rated excellent for marginal integrity. Average visual analogue scale (VAS) score for tooth sensitivity decreased from 7.63 mm at baseline to 0.44 mm at 6-month recall, 0.20 mm at 1-year recall, and 0.00 mm at 2- and 3-year recall. Average gingival index (GI) score for gingival inflammation decreased from 0.56 at baseline to 0.11 at 6-month recall, 0.16 at 1-year recall, 0.21 at 2-year recall, and 0.07 at 3-year recall. After periodic recalls up to 3 years, Ceramir C&B thus far has performed quite favorably as a luting agent for permanent cementation of permanent restorations. In-vitro crown-coping retention studies were also conducted using this cement and various control cementation materials. Mean laboratory retentive forces measured for Ceramir C&B were comparable to other currently available luting agents for both metal and all-ceramic indirect restorative materials. PMID:23577551

Jefferies, Steven R; Pameijer, Cornelis H; Appleby, David C; Boston, Daniel; Lööf, Jesper

2013-02-01

197

Biocompatibility: bioengineering aspects.  

PubMed

Bioengineers have contributed to biocompatibility research. Many materials have been designed, synthesized and characterized by use of various analytical instruments. The blood compatibility of materials has been studied by focusing on the blood-material interfacial reactions. Although much information has been accumulated regarding such local reactions, understanding of biocompatibility is still limited. A more global approach to study is needed. A new approach to understanding biocompatibility is proposed and discussed. Three points are stressed: interaction within body's defense system and its effect on blood-material reactions; induction of a systemic reaction by a local reaction, which then affects the blood-material interaction; the time sequence of such interactions between local and systemic reactions. To establish a logical approach to study biocompatibility is most important at this moment for the future progress in biocompatibility research. PMID:23442243

Murabayashi, Shun; Nose, Yukihiko

2013-01-01

198

Fiber-enriched double-setting calcium phosphate bone cement  

Microsoft Academic Search

Calcium phosphate bone cements are useful in orthopedics and traumatology, their main advantages being their biocompatibility and bioactivity, which render bone tissue osteoconductive, providing in situ hardening and easy handling. However, their low mechanical strength, which, in the best of cases, is equal to the trabecular bone, and their very low toughness are disadvantages. Calcium phosphate cement compositions with mechanical

Luis Alberto dos Santos; Raul Garcia Carrodeguas; Anselmo Ortega Boschi

199

?-Tricalcium phosphate cement: “in vitro” cytotoxicity  

Microsoft Academic Search

Calcium phosphate-based bioceramics have revolutionized orthopedic and dental repair of damaged parts of the bone system. Among these materials, calcium phosphate-based cements, with hydraulic setting, stand out due to their biocompatibility and in situ hardening, which allow easy manipulation and adaptation to the shape and dimensions of bone defects. An investigation was made of the in vitro cytotoxic effect of

L. A. dos Santosa; R. G Carrodéguas; S. O Rogero; O. Z Higa; A. O Boschi; A. C. F de Arruda

2002-01-01

200

Biocompatibility of Graphene Oxide  

Microsoft Academic Search

Herein, we report the effects of graphene oxides on human fibroblast cells and mice with the aim of investigating graphene oxides' biocompatibility. The graphene oxides were prepared by the modified Hummers method and characterized by high-resolution transmission electron microscope and atomic force microscopy. The human fibroblast cells were cultured with different doses of graphene oxides for day 1 to day

Kan Wang; Jing Ruan; Hua Song; Jiali Zhang; Yan Wo; Shouwu Guo; Daxiang Cui

2011-01-01

201

Rigidity and retention of ceramic root canal posts.  

PubMed

Ceramic root-canal posts offer potential advantages over other types with respect to aesthetics and biocompatibility. Any post must be sufficiently rigid and retentive to withstand functional forces. Ceraposts (1.2 mm coronal diameter, ceramic, tapering, smooth posts) and Paraposts (1.25 mm, stainless-steel, parallel, serrated posts) were tested for rigidity by means of a three-point bending test. To test retention in roots, ceramic posts were cemented using one of three protocols: (1) glass-ionomer cement, (2) silane coupling agent and resin cement, or (3) sandblasted post surface, silane coupling agent, and resin cement. Stainless-steel posts were cemented with resin. The tensile force required to dislodge the posts, following four weeks of storage in water, was recorded. Data were compared using Student's t-test and Mann-Whitney U analysis. Ceraposts were significantly more rigid than Paraposts (p < 0.001). Paraposts cemented with resin were significantly more strongly retained than Ceraposts following any cementation protocol (p < 0.001). Retention of the ceramic posts was significantly greater with a silane coupling agent and resin cement than with glass-ionomer cement (p < 0.001). Sandblasting the ceramic posts produced variable results and needs further investigation before it could be recommended. PMID:11203820

Purton, D G; Love, R M; Chandler, N P

202

Flouride release from various restorative materials.  

PubMed

Fluoride release from six light-activated restorative materials, including two resinmodified glass-ionomers, two composites, and two compomers, was evaluated and compared with one conventional acid-based glass-ionomer cement. The amount and rate of release varied among the tested materials. Both resin-modified glass-ionomers and the conventional acid-base glass-ionomer cements released more fluoride then the composites and compomers (p < 0.05). Additionally, composite materials released less fluoride than compomer materials (p < 0.05). Release of fluoride by the tested materials showed a significant decrease after all the tested time intervals. PMID:9354026

Bala, O; Uçta?li, M; Can, H; Türköz, E; Can, M

1997-09-01

203

Biocompatibility and membrane development.  

PubMed

Development of new biocompatible membranes for clinical application needs the expertise of various specialists, chemists, chemical engineers, and clinicians. As the biocompatibility of a membrane cannot be considered in terms of a single biochemical pathway, due to the interrelation between the complement, coagulation, and inflammatory systems, it is difficult to achieve optimal results with one single polymer. A compromise between different approaches has therefore to be found. Membrane development also needs sophisticated test systems, which simulate the clinical situation as closely as possible. Adequate results are achieved with the 'ex vivo' model, which represents open-loop haemodialysis. The ex vivo model gives good results which are close to those from clinical experiments. PMID:1775260

Baurmeister, U; Vienken, J; Grassmann, A

1991-01-01

204

Biocompatibility and osteogenetic characteristics of new biocompatible glasses.  

PubMed

A fibre-shaped glass with qualities of biocompatibility and biodegradation could be promising for reconstructive bone surgery in orthopaedics and neurosurgery. New highly biocompatible glasses, originally made by the Italian Group of Study on Biocompatible Glass, are obtained both in cylinder and fibre shapes due to their original chemical composition (Glassfiber). This is the only glass which is also available as a continuous filament. Hydrolytic in vitro and in vivo tests demonstrate that these glasses present both good biocompatibility and adjustable biodegradation in relation to their chemical composition. The advantages of bioactive glass also being available as a continuous filament are suggested. PMID:1772954

Barbon, F; Locardi, B; Verità, M; Gabbi, C; Grispigni, C; Tranquilli Leali, P; Brach del Prever, E; Gallinaro, P; Cerulli, G; Del Bue, G L

1991-08-01

205

Biocompatibility of composite resins  

PubMed Central

Dental materials that are used in dentistry should be harmless to oral tissues, so they should not contain any leachable toxic and diffusible substances that can cause some side effects. Reports about probable biologic hazards, in relation to dental resins, have increased interest to this topic in dentists. The present paper reviews the articles published about biocompatibility of resin-restorative materials specially resin composites and monomers which are mainly based on Bis-GMA and concerns about their degradation and substances which may be segregated into oral cavity.

Mousavinasab, Sayed Mostafa

2011-01-01

206

In vivo behavior of three different injectable hydraulic calcium phosphate cements.  

PubMed

Two dicalcium phosphate dihydrate (DCPD) hydraulic cements and one apatite hydraulic cement were implanted in epiphyseal and metaphyseal, cylindrical bone defects of sheep. The in vivo study was performed to assess the biocompatibility of the DCPD cements, using the apatite cement as control. After time periods of 2, 4 and 6 months the cement samples were clinically and histologically evaluated. Histomorphometrically the amount of new bone formation, fibrous tissue and the area of remaining cement were measured over time. In all specimens, no signs of inflammation were detectable either macroscopically or microscopically. All cements were replaced by different amounts of new bone. The two DCPD-cements showed the highest new bone formation and least cement remnants at 6 months, whereas the apatite was almost unchanged over all time periods. PMID:14643619

Apelt, D; Theiss, F; El-Warrak, A O; Zlinszky, K; Bettschart-Wolfisberger, R; Bohner, M; Matter, S; Auer, J A; von Rechenberg, B

207

Setting Reaction and Hardening of an Apatitic Calcium Phosphate Cement  

Microsoft Academic Search

The combination of self-setting and biocompatibility makes calcium phosphate cements potentially useful materials for a variety of dental applications. The objective of this study was to investigate the setting and hardening mechanisms of a cement-type reaction leading to the formation of calcium-deficient hydroxyapatite at low temperature. Reactants used were a-tricalcium phosphate containing 17 wt% ?-tricalcium phosphate, and 2 wt% of

M. P. Ginebra; E. Fernández; E. A. P. De Maeyer; R. M. H. Verbeeck; M. G. Boltong; J. Ginebra; F. C. M. Driessens; J. A. Planell

1997-01-01

208

BoneSource? hydroxyapatite cement: A novel biomaterial for craniofacial skeletal tissue engineering and reconstruction  

Microsoft Academic Search

BoneSource TM-hydroxyapatite cement is a new self-setting calcium phosphate cement biomaterial. Its unique and innovative physical chemistry coupled with enhanced biocompatibility make it useful for craniofacial skeletal reconstruction. The general prop- erties and clinical use guidelines are reviewed. The biomaterial and surgical applications offer insight into improved outcomes and potential new uses for hydroxyapatite cement systems. q 1998 John Wiley

Craig D. Friedman; Peter D. Costantino; Shozo Takagi; Lawrence C. Chow

1998-01-01

209

Cement-based thermocouples  

Microsoft Academic Search

A cement-based thermocouple in the form of a junction between dissimilar cement pastes and exhibiting thermocouple sensitivity 70±7 ?V\\/°C is provided. The dissimilar cement pastes are steel fiber cement paste (n-type) and carbon-fiber silica-fume cement paste (p-type). The junction is made by pouring the cement pastes side by side.

Sihai Wen; D. D. L. Chung

2001-01-01

210

Biocompatibility of Graphene Oxide  

NASA Astrophysics Data System (ADS)

Herein, we report the effects of graphene oxides on human fibroblast cells and mice with the aim of investigating graphene oxides' biocompatibility. The graphene oxides were prepared by the modified Hummers method and characterized by high-resolution transmission electron microscope and atomic force microscopy. The human fibroblast cells were cultured with different doses of graphene oxides for day 1 to day 5. Thirty mice divided into three test groups (low, middle, high dose) and one control group were injected with 0.1, 0.25, and 0.4 mg graphene oxides, respectively, and were raised for 1 day, 7 days, and 30 days, respectively. Results showed that the water-soluble graphene oxides were successfully prepared; graphene oxides with dose less than 20 ?g/mL did not exhibit toxicity to human fibroblast cells, and the dose of more than 50 ?g/mL exhibits obvious cytotoxicity such as decreasing cell adhesion, inducing cell apoptosis, entering into lysosomes, mitochondrion, endoplasm, and cell nucleus. Graphene oxides under low dose (0.1 mg) and middle dose (0.25 mg) did not exhibit obvious toxicity to mice and under high dose (0.4 mg) exhibited chronic toxicity, such as 4/9 mice death and lung granuloma formation, mainly located in lung, liver, spleen, and kidney, almost could not be cleaned by kidney. In conclusion, graphene oxides exhibit dose-dependent toxicity to cells and animals, such as inducing cell apoptosis and lung granuloma formation, and cannot be cleaned by kidney. When graphene oxides are explored for in vivo applications in animal or human body, its biocompatibility must be considered.

Wang, Kan; Ruan, Jing; Song, Hua; Zhang, Jiali; Wo, Yan; Guo, Shouwu; Cui, Daxiang

2010-12-01

211

Biocompatibility of Graphene Oxide  

NASA Astrophysics Data System (ADS)

Herein, we report the effects of graphene oxides on human fibroblast cells and mice with the aim of investigating graphene oxides' biocompatibility. The graphene oxides were prepared by the modified Hummers method and characterized by high-resolution transmission electron microscope and atomic force microscopy. The human fibroblast cells were cultured with different doses of graphene oxides for day 1 to day 5. Thirty mice divided into three test groups (low, middle, high dose) and one control group were injected with 0.1, 0.25, and 0.4 mg graphene oxides, respectively, and were raised for 1 day, 7 days, and 30 days, respectively. Results showed that the water-soluble graphene oxides were successfully prepared; graphene oxides with dose less than 20 ?g/mL did not exhibit toxicity to human fibroblast cells, and the dose of more than 50 ?g/mL exhibits obvious cytotoxicity such as decreasing cell adhesion, inducing cell apoptosis, entering into lysosomes, mitochondrion, endoplasm, and cell nucleus. Graphene oxides under low dose (0.1 mg) and middle dose (0.25 mg) did not exhibit obvious toxicity to mice and under high dose (0.4 mg) exhibited chronic toxicity, such as 4/9 mice death and lung granuloma formation, mainly located in lung, liver, spleen, and kidney, almost could not be cleaned by kidney. In conclusion, graphene oxides exhibit dose-dependent toxicity to cells and animals, such as inducing cell apoptosis and lung granuloma formation, and cannot be cleaned by kidney. When graphene oxides are explored for in vivo applications in animal or human body, its biocompatibility must be considered.

Wang, Kan; Ruan, Jing; Song, Hua; Zhang, Jiali; Wo, Yan; Guo, Shouwu; Cui, Daxiang

2011-12-01

212

Biocompatibility of Graphene Oxide  

PubMed Central

Herein, we report the effects of graphene oxides on human fibroblast cells and mice with the aim of investigating graphene oxides' biocompatibility. The graphene oxides were prepared by the modified Hummers method and characterized by high-resolution transmission electron microscope and atomic force microscopy. The human fibroblast cells were cultured with different doses of graphene oxides for day 1 to day 5. Thirty mice divided into three test groups (low, middle, high dose) and one control group were injected with 0.1, 0.25, and 0.4 mg graphene oxides, respectively, and were raised for 1 day, 7 days, and 30 days, respectively. Results showed that the water-soluble graphene oxides were successfully prepared; graphene oxides with dose less than 20 ?g/mL did not exhibit toxicity to human fibroblast cells, and the dose of more than 50 ?g/mL exhibits obvious cytotoxicity such as decreasing cell adhesion, inducing cell apoptosis, entering into lysosomes, mitochondrion, endoplasm, and cell nucleus. Graphene oxides under low dose (0.1 mg) and middle dose (0.25 mg) did not exhibit obvious toxicity to mice and under high dose (0.4 mg) exhibited chronic toxicity, such as 4/9 mice death and lung granuloma formation, mainly located in lung, liver, spleen, and kidney, almost could not be cleaned by kidney. In conclusion, graphene oxides exhibit dose-dependent toxicity to cells and animals, such as inducing cell apoptosis and lung granuloma formation, and cannot be cleaned by kidney. When graphene oxides are explored for in vivo applications in animal or human body, its biocompatibility must be considered.

2011-01-01

213

Fatigue testing and microscopic evaluation of post and core restorations under artificial crowns  

Microsoft Academic Search

Statement of problem. Coronoradicular reconstruction techniques of pulpless teeth include prefabricated post systems that retain a core material such as silver amalgam, composite, glass ionomer, or modified glass ionomer cement. Mechanical properties of these materials are critical to sustain masticatory forces. Purpose. This in vitro study compared the mechanical resistance of 3 core materials (silver amalgam, composite, and silver-reinforced glass

Philippe Gateau; Marc Sabek; Bruno Dailey

1999-01-01

214

Biocompatibility of Dental Amalgams  

PubMed Central

Objective. The purpose of this review paper is to review the literature regarding the toxicology of mercury from dental amalgam and evaluate current statements on dental amalgam. Materials and Methods. Two key-words “dental amalgam” and “toxicity” were used to search publications on dental amalgam biocompatibility published in peer-reviewed journals written in English. Manual search was also conducted. The most recent declarations and statements were evaluated using information available on the internet. Case reports were excluded from the study. Results. The literature show that mercury released from dental amalgam restorations does not contribute to systemic disease or systemic toxicological effects. No significant effects on the immune system have been demonstrated with the amounts of mercury released from dental amalgam restorations. Only very rarely have there been reported allergic reactions to mercury from amalgam restorations. No evidence supports a relationship between mercury released from dental amalgam and neurological diseases. Almost all of the declarations accessed by the internet stated by official organizations concluded that current data are not sufficient to relate various complaints and mercury release from dental amalgam. Conclusions. Available scientific data do not justify the discontinuation of amalgam use from dental practice or replacement with alternative restorative dental materials.

Ucar, Yurdanur; Brantley, William A.

2011-01-01

215

Electrospinning of Biocompatible Nanofibers  

NASA Astrophysics Data System (ADS)

Artificial scaffolds for growing cells can have a wide range of applications including wound coverings, supports in tissue cultures, drug delivery, and organ and tissue transplantation. Tissue engineering is a promising field which may resolve current problems with transplantation, such as rejection by the immune system and scarcity of donors. One approach to tissue engineering utilizes a biodegradable scaffold onto which cells are seeded and cultured, and ideally develop into functional tissue. The scaffold acts as an artificial extracellular matrix (ECM). Because a typical ECM contains collagen fibers with diameters of 50-500 nm, electrostatic spinning (electrospinning) was used to mimic the size and structure of these fibers. Electrospinning is a novel way of spinning a nonwoven web of fibers on the order of 100 nm, much like the web of collagen in an ECM. We are investigating the ability of several biocompatible polymers (e.g., chitosan and polyvinyl alcohol) to form defect-free nanofiber webs and are studying the influence of the zero shear rate viscosity, molecular weight, entanglement concentration, relaxation time, and solvent on the resulting fiber size and morphology.

Coughlin, Andrew J.; Queen, Hailey A.; McCullen, Seth D.; Krause, Wendy E.

2006-03-01

216

Sculpting with Cement.  

ERIC Educational Resources Information Center

Cement offers many creative possibilities for school art programs. Instructions are given for sculpting with fiber-cement and sand-cement, as well as for finishing processes and the addition of color. Safety is stressed. (IS)

Olson, Lynn

1983-01-01

217

Method of making biocompatible electrodes  

SciTech Connect

A process of improving the sensing function of biocompatible electrodes and the product so made are disclosed. The process is designed to alter the surfaces of the electrodes at their tips to provide increased surface area and therefore decreased contact resistance at the electrode-tissue interface for increased sensitivity and essentially includes rendering the tips atomically clean by exposing them to bombardment by ions of an inert gas, depositing an adhesion layer on the cleaned tips, forming a hillocked layer on the adhesion layer by increasing the temperature of the tips, and applying a biocompatible coating on the hillocked layer. The resultant biocompatible electrode is characterized by improved sensitivity, minimum voltage requirement for organ stimulation and a longer battery life for the device in which it is employed. 16 figs.

Wollam, J.S.

1992-06-02

218

Beta-tricalcium phosphate release from brushite cement surface.  

PubMed

Different in vivo studies demonstrated that brushite cements are biocompatible, bioresorbable, and osteoconductive. However, the decay of brushite cements has been scarcely studied even though it may be of great concern for clinical applications in highly blood-perfused regions. This work was elaborated to elucidate factors that determine brushite cement surface disintegration. For that, brushite cements were modified using in their preparation different aqueous solutions of phosphoric, glycolic, tartaric, and citric acids in concentrations that were reported to improve the cement properties. Two-viscosity enhancing polysaccharides, chondroitin-4 sulfate and hyaluronic acid, were also assayed. Thereafter, pre- and set cement samples were immersed in distilled water for 24 h. The cement-solid weight loss, microstructure, liquid phase viscosity, mean size of the released particles, and zeta potential were analyzed using X-ray diffraction, FTIR spectroscopy, light scattering, scanning electron microscopy and optical microscopy. It was found that the particles released from the cement surface were beta-TCP, and their amount depends on the carboxylic acid used in the preparation of the cement. The addition of hyaluronic acid and chondroitin-4 sulfate decreased the amount of released particles from the surface of the set brushite cement made with citric acid. Furthermore, the hyaluronic acid increased significantly the viscosity of the citric acid solution and the cement paste prepared with this liquid phase showed a pronounced step down in particle release. In this study, we showed that the water solubility of calcium carboxylate and the viscosity of mixing liquid may dictate the superficial disintegration of brushite cements. PMID:17635024

Alkhraisat, M Hamdan; Mariño, F Tamimi; Retama, J Rubio; Jerez, L Blanco; López-Cabarcos, E

2008-03-01

219

Biocompatibility of mesoporous silica nanoparticles.  

PubMed

In this review, recent reports on the biocompatibility of mesoporous silica nanoparticles (MSNs) are reviewed, with special emphasis being paid to the correlations between MSNs' structural and compositional features and their biological effects on various cells and tissues. First, the different synthetic routes used to produce the most common types of MSNs and the various methods employed to functionalize their surfaces are discussed. This is, however, done only briefly because of the focus of the review being the biocompatibility of the materials. Similarly, the biological applications of MSNs in areas such as drug and gene delivery, biocatalysis, bioimaging, and biosensing are briefly introduced. Many examples have also been mentioned about the biological applications of MSNs while discussing the materials' biocompatibility. The cytotoxicity of different types of MSNs and the effects of their various structural characteristics on their biological activities, which are the focus of this review, are then described in detail. In addition, synthetic strategies developed to reduce or eliminate any possible negative biological effects associated with MSNs or to improve their biocompatibility, as necessary, are illustrated. At the same time, recent reports on the interactions between MSNs and various in vivo or in vitro biological systems, plus our opinions and remarks on what the future may hold for this field, are included. PMID:22823891

Asefa, Tewodros; Tao, Zhimin

2012-08-10

220

Biocompatibility of implantable biomedical devices  

NASA Astrophysics Data System (ADS)

Biomedical devices have been broadly used to treat human disease, especially chronic diseases where pharmaceuticals are less effective. Heart valve and artificial joint are examples. Biomedical devices perform by delivering therapies such as electric stimulations, mechanical supports and biological actions. While the uses of biomedical devices are highly successful they can trigger adverse biological reactions as well. The property that medical devices perform with intended functions but not causing unacceptable adverse effects was called biocompatibility in the early time. As our understanding of biomaterial-biological interactions getting broader, biocompatibility has more meanings. In this talk, I will present some adverse biological reactions observed with implantable biomedical devices. Among them are surface fouling of implantable sensors, calcification with vascular devices, restenosis with stents, foreign particle migration and mechanical fractures of devices due to inflammation reactions. While these effects are repeatable, there are very few quantitative data and theories to define them. The purpose of this presentation is to introduce this biocompatibility concept to biophysicists to stimulate research interests at different angles. An open question is how to quantitatively understand the biocompatibility that, like many other biological processes, has not been quantified experimentally.

Lyu, Suping

2008-03-01

221

Principles of biocompatibility for dental practitioners  

Microsoft Academic Search

This article is an evidence-based tutorial on the principles of biocompatibility. Although the technical issues of biocompatibility may seem beyond the scope of most practicing dentists, knowledge of these issues is fundamentally important to ensure the health of patients, dental staff members (including laboratory personnel), and practitioners themselves. Furthermore, the legal liability of dentists is often linked to biocompatibility issues.

John C. Wataha

2001-01-01

222

Biocompatibility of Artificial Organs: An Overview  

Microsoft Academic Search

Papers that are presented in this symposium on biocompatibility of foreign surfaces used in artificial organs are commented upon and set in an overall context of the biocompatibility of foreign surfaces to blood. A working formulation of the events comprising lack of biocompatibility of hemodialysis membranes to the complement system is given as a possible model to which other foreign

Lee W. Henderson; Dennis Chenoweth

1987-01-01

223

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that was performed to analyze the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2002-07-30

224

Histopathological reactions of calcium phosphate cement.  

PubMed

Calcium phosphate cement (CPC) consisting of Ca4 (PO4)2O and CaHPO4 (2H2O) was recently developed. This study evaluated in vivo aspects of CPC and CPC mixtures compared to those of commercial hydroxyapatite (HP) and several endodontic materials: Grossman's cement (GC), calcium hydroxide-iodine paste (CHP) and gutta-percha plate (GP). Biocompatibility of subcutaneous implants in Donryu rats was evaluated after one month. Results showed very slight inflammatory reactions from CPC, CPC mixtures and HP. The materials were surrounded by thin fibrous connective tissues with a small number of lymphocytes and plasma cells. Severe inflammatory reactions were provoked by GC. Granulation tissues induced by CHP resembled those of pseudoxanthomatous granuloma. The GP material was encapsulated by relatively thick fibrous connective tissues with little inflammatory reactions. PMID:1327659

Sugawara, A; Nishiyama, M; Kusama, K; Moro, I; Nishimura, S; Kudo, I; Chow, L C; Takagi, S

1992-06-01

225

Bone regeneration with glass ceramic implants and calcium phosphate cements in a rabbit cranial defect model  

Microsoft Academic Search

Hydroxyapatite cement (BoneSource®) and brushite calcium phosphate cement (chronOS™ Inject) were tested for fixation of glass\\u000a ceramic implants (Bioverit®) in experimentally created cranial defects in 24 adult New Zealand White rabbits. Aim of the in\\u000a vivo study was to assess and compare the biocompatibility and osseointegration of the implanted materials. Macroscopic and\\u000a histological evaluations were performed 1 month, 3 months, and 6 months

Gerlind Schneider; Karin Blechschmidt; Dirk Linde; Peter Litschko; Thomas Körbs; Eggert Beleites

2010-01-01

226

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

PubMed

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

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

2000-09-01

227

THE BIOCOMPATIBILITY OF MESOPOROUS SILICATES  

PubMed Central

Micro- and nano- mesoporous silicate particles are considered potential drug delivery systems because of their ordered pore structures, large surface areas and the ease with which they can be chemically modified. However, few cytotoxicity or biocompatibility studies have been reported, especially when silicates are administered in the quantities necessary to deliver low-potency drugs. The biocompatibility of mesoporous silicates of particle sizes ~ 150 nm, ~ 800 nm and ~ 4 µm and pore sizes of 3 nm, 7 nm and 16 nm respectively are examined here. In vitro, mesoporous silicates showed a significant degree of toxicity at high concentrations with mesothelial cells. Following subcutaneous injection of silicates in rats, the amount of residual material decreased progressively over three months, with good biocompatibility on histology at all time points. In contrast, intra peritoneal and intra venous injections in mice resulted in death or euthanasia. No toxicity was seen with subcutaneous injection of the same particles in mice. Microscopic analysis of the lung tissue of the mice indicates that death may be due to thrombosis. Although local tissue reaction to mesoporous silicates was benign, they caused severe systemic toxicity. This toxicity could be mitigated by modification of the materials.

Hudson, Sarah; Padera, Robert F.; Langer, Robert; Kohane, Daniel S.

2008-01-01

228

Effective formulations for the preparation of calcium phosphate bone cements  

Microsoft Academic Search

In the system CaO-P2O5-H2O 13 different solids with varying Ca\\/P ratios are known. In addition calcium phosphates containing other biocompatible constituents like Na, or K, or Mg or Cl or carbonate, are known. Therefore, a large number of combinations of such compounds is possible which might result in the formation of calcium phosphate cements upon mixing with water. However, the

F. C. M. Driessens; M. G. Boltong; O. Bermúdez; J. A. Planell; M. P. Ginebra; E. Fernández

1994-01-01

229

In vivo evaluation of an injectable Macroporous Calcium Phosphate Cement  

Microsoft Academic Search

Although Calcium Phosphate Cements (CPC) are highly biocompatible and osteconductive materials, its resorption rate still\\u000a remains too slow for some applications. In this work the introduction of Macroporosity in an injectable CPC is evaluated as\\u000a a way to accelerate resorption and to increase bone ingrowth. A Macroporous and a standard CPC were injected just after preparation\\u000a in a defect drilled

Sergio del Valle; Natalia Miño; Fernando Muñoz; Antonio González; Josep A. Planell; Maria-Pau Ginebra

2007-01-01

230

Cytotoxicity of resin-based restorative materials on human pulp cell cultures  

Microsoft Academic Search

Objective. The objective of this study was to determine the cytocompatibility of 5 different extracts of resin-based restorative materials (2 resin-modified glass ionomer cements, 1 compomer, and 2 composite resins) on human pulp cells. Study Design. Set specimens from 2 resin-modified glass-ionomer cements (Fuju II LC and Fuji IX), 1 compomer (Dyract), and 2 composite resins (Tetric and Superfil) were

Fu-Mei Huang; Yu-Chao Chang

2002-01-01

231

Storage of polyacid-modified resin composites (“compomers”) in lactic acid solution  

Microsoft Academic Search

Objectives: The aim of this study was to determine the interaction of four polyacid-modified resin composites with aqueous lactic acid solutions, and to compare changes with those for a glass-ionomer cement and a conventional resin composite.Methods: For each material, namely Compoglass F, Dyract AP, Hytac and Ana Compomer, plus AquaCem (glass-ionomer cement) and Pekafil (conventional composite resin), five cylindrical specimens

J. W. Nicholson; B. J. Millar; B. Czarnecka; H. Limanowska-Shaw

1999-01-01

232

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra- lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2003-10-31

233

Flexible Glucose Sensor Using Biocompatible Polymers  

Microsoft Academic Search

A flexible amperometric glucose sensor formed on biocompatible polymer was fabricated and tested. The sensor was fabricated by laminating biocompatible polymers and film electrodes. Functional and biocompatible polymers of polydimethyl siloxane (PDMS) and 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymerized with dodecyl methacrylate (DMA) were utilized as the sensor material. Particularly, poly (MPC-co-DMA) (PMD) was not only used as a gas-permeable layer by

Hiroyuki Kudo; Takanori Sawada; Ming Xing Chu; T. Saito; H. Saito; K. Otsuka; Y. Iwasaki; K. Mitsubayashi

2006-01-01

234

Setting properties, mechanical strength and in vivo evaluation of calcium phosphate-based bone cements  

Microsoft Academic Search

Calcium phosphate cement (CPC) is a promising material for use in minimally invasive surgery for bone defect repair due to its similarity to the mineral phase of bone, biocompatibility, bioactivity, self-setting characteristics, low setting temperature, adequate stiffness and ease of shaping in complicated geometrics. In this study, we systematically investigate the influence of preparation variables on the final properties of

So Yeon Kim; Sung Hyun Jeon

235

Biocompatibility of biomaterials: hemocompatibility, immunocompatiblity and biocompatibility of solid polymeric materials and soluble targetable polymeric carriers  

Microsoft Academic Search

The biocompatibility and immunocompatibility of polymeric materials is of fundamental importance for their possible therapeutic uses. Aspects of biocompatibility of solid polymeric materials and soluble polymeric materials differ. Solid materials are used in polymer implants, as membranes in kidney dialysis and cardiopulmonary bypass, for polymer coating of other materials to increase their biocompatibility, for encapsulation of cells producing hormones and

Blanka ?íhová

1996-01-01

236

A novel injectable bioactive bone cement for spinal surgery: a developmental and preclinical study.  

PubMed

The injection of bone cement by minimally invasive techniques for the treatment of vertebral body fractures or for stabilization of an osteoporotic vertebral body is regarded as promising in spinal surgery. The purpose of this study was to develop a novel injectable bioactive bone cement to address such concerns. The cement was composed mainly of strontium-containing hydroxyapatite (Sr-HA) filler and Bisphenol A Diglycidylether Dimethacrylate (D-GMA) resin. The Sr-HA filler was prepared by precipitation and calcination, then analyzed with Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) patterns. Samples of strontium-containing hydroxyapatite cement (SrHAC) were formed by a combination of powder filler and resin matrix, with the setting time and peak temperature recorded. Cell relative growth rate (RGR), Tetrazolium bromide (MTT), and haemolysis tests were used to detect initial in vitro biocompatibility of the new cement. In vitro spinal biomechanical testing and morphological observation after bone cement injection were performed on pig spines. Results indicate that the setting time and peak temperature of the cement was 15 min and 55 degrees C, respectively. Cytotoxicity of the cement was class 1 (no cytotoxicity) and haemolysis was 1% (no haemolysis). Stiffness after cement injection and fatigue loading were 112% and 95% of the intact bone, respectively, which is similar to that of natural bone. Radiopacity of SrHAC allowed easy radiographic imaging. The use of SrHAC cement is, thus, promising in spinal surgery. PMID:10906688

Li, Y W; Leong, J C; Lu, W W; Luk, K D; Cheung, K M; Chiu, K Y; Chow, S P

2000-10-01

237

Multiple cemental tears.  

PubMed

A cemental tear is a pathologic condition in which a complete or incomplete separation of the cementum occurs along the root surface and is usually accompanied by a deep periodontal pocket. Past articles report that the incidence of cemental tears has usually been limited to 1 tooth per individual. We encountered a clinical case with cemental tears involving 14 teeth in 1 individual. Multiple cemental tears in 1 individual have not been previously described in the dental literature. We present the clinical and pathologic features of this rare case and suggest that the probable cause of multiple cemental tears is structural weakness of the cementum. PMID:22862978

Watanabe, Chie; Watanabe, Yoshihisa; Miyauchi, Mutsumi; Fujita, Minoru; Watanabe, Yoshiyuki

2012-03-05

238

CHH Cement Composite  

NASA Astrophysics Data System (ADS)

The compressive strength and electrical resistivity for hardened pastes produced from nanomodified Portland SR cement (CHH- Carbon Hedge Hog cement) were studied. The nanomodification included growing of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on the cement particles. Pastes having water to binder ratio of 0.5 were produced. The obtained hardened material was characterized by increased compressive strength in comparison with the reference specimens made from pristine SR cement, which was attributed to reinforcing action of the CNTs and CNFs. The electrical resistivity of CHH composite was lower by one order of magnitude in comparison with reference Portland cement paste.

Cwirzen, A.; Habermehl-Cwirzen, K.; Nasibulina, L. I.; Shandakov, S. D.; Nasibulin, A. G.; Kauppinen, E. I.; Mudimela, P. R.; Penttala, V.

239

Hyperbranched Glycopolymers for Blood Biocompatibility.  

PubMed

Carbohydrate-based drug and gene delivery carriers are becoming extremely popular for in vitro and in vivo applications. These carriers are found to be nontoxic and can play a significant role in targeted delivery. However, the interactions of these carriers with blood cells and plasma components are not well explored. To the best of our knowledge, there are currently no reports that explore the role of carbohydrate based carriers for blood biocompatibility. Hyperbranched glycopolymers of varying molecular weights are synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT) and are studied in detail for their biocompatibility, including hemocompatibility and cytotoxicity against different cell lines in vitro. The hemocompatibility studies (such as hemolysis and platelet activation) indicate that hyperbranched glycopolymers of varying molecular weights produced are highly hemocompatible and do not induce clot formation, red blood cell aggregation, and immune response. Hence, it can be concluded that glycopolymers functionalized carriers can serve as an excellent candidate for various biomedical applications. In addition, cytotoxicity of these hyperbranched polymers is studied in primary and malignant cell lines at varying concentrations using cell viability assay. PMID:22500726

Ahmed, Marya; Lai, Benjamin F L; Kizhakkedathu, Jayachandran N; Narain, Ravin

2012-04-24

240

Biocompatibility of plasma nanostructured biopolymers  

NASA Astrophysics Data System (ADS)

Many areas of medicine such as tissue engineering requires not only mastery of modification techniques but also thorough knowledge of the interaction of cells with solid state substrates. Plasma treatment can be used to effective modification, nanostructuring and therefore can significantly change properties of materials. In this work the biocompatibility of the plasma nanostructured biopolymers substrates was studied. Changes in surface chemical structure were studied by X-ray photoelectron spectroscopy (XPS). The morphology pristine and modified samples were determined using atomic force microscopy (AFM). The surface wettability was determined by goniometry from contact angle. Biocompatibility was determined by in vitro tests, the rat vascular smooth muscle cells (VSMCs) were cultivated on the pristine and plasma modified biopolymer substrates. Their adhesion, proliferation, spreading and homogeneous distribution on polymers was monitored. It was found that the plasma treatment leads to rapid decrease of contact angle for all samples. Contact angle decreased with increasing time of modification. XPS measurements showed that plasma treatment leads to changes in ratio of polar and non-polar groups. Plasma modification was accompanied by a change of surface morphology. Biological tests found that plasma treatment have positive effect on cells adhesion and proliferation cells and affects the size of cell's adhesion area. Changes in plasma power or in exposure time influences the number of adhered and proliferated cells and their distribution on biopolymer surface.

Slepi?ková Kasálková, N.; Slepi?ka, P.; Ba?áková, L.; Sajdl, P.; Švor?ík, V.

2013-07-01

241

Factors influencing alginate gel biocompatibility.  

PubMed

Alginate remains the most popular polymer used for cell encapsulation, yet its biocompatibility is inconsistent. Two commercially available alginates were compared, one with 71% guluronate (HiG), and the other with 44% (IntG). Both alginates were purified, and their purities were verified. After 2 days in the peritoneal cavity of C57BL/6J mice, barium (Ba)-gel and calcium (Ca)-gel beads of IntG alginate were clean, while host cells were adhered to beads of HiG alginate. IntG gel beads, however, showed fragmentation in vivo while HiG gel beads stayed firm. The physicochemical properties of the sodium alginates and their gels were thoroughly characterized. The intrinsic viscosity of IntG alginate was 2.5-fold higher than that of HiG alginate, suggesting a greater molecular mass. X-ray photoelectron spectroscopy indicated that both alginates were similar in elemental composition, including low levels of counterions in all gels. The wettabilities of the alginates and gels were also identical, as measured by contact angles of water on dry films. Ba-gel beads of HiG alginate resisted swelling and degradation when immersed in water, much more than the other gel beads. These results suggest that the main factors contributing to the biocompatibility of gels of purified alginate are the mannuronate/guluronate content and/or intrinsic viscosity. PMID:21523903

Tam, Susan K; Dusseault, Julie; Bilodeau, Stéphanie; Langlois, Geneviève; Hallé, Jean-Pierre; Yahia, L'Hocine

2011-04-26

242

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that will be performed for analyzing the alkali-silica reactivity of ULHS in cement slurries, as well as the results of Field Tests 1 and 2.

Fred Sabins

2002-10-31

243

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, and shear bond. Testing to determine the effect of temperature cycling on the shear bond properties of the cement systems was also conducted. In addition, the stress-strain behavior of the cement types was studied. This report discusses a software program that is being developed to help design ULHS cements and foamed cements.

Fred Sabins

2002-04-29

244

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Issues, Task 2: Review Russian Ultra-Lightweight Cement Literature, Task 3: Test Ultra-Lightweight Cements, and Task 8: Develop Field ULHS Cement Blending and Mixing Techniques. Results reported this quarter include: preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; summary of pertinent information from Russian ultra-lightweight cement literature review; laboratory tests comparing ULHS slurries to foamed slurries and sodium silicate slurries for two different applications; and initial laboratory studies with ULHS in preparation for a field job.

Fred Sabins

2001-07-18

245

Fiber-enriched double-setting calcium phosphate bone cement.  

PubMed

Calcium phosphate bone cements are useful in orthopedics and traumatology, their main advantages being their biocompatibility and bioactivity, which render bone tissue osteoconductive, providing in situ hardening and easy handling. However, their low mechanical strength, which, in the best of cases, is equal to the trabecular bone, and their very low toughness are disadvantages. Calcium phosphate cement compositions with mechanical properties more closely resembling those of human bone would broaden the range of applications, which is currently limited to sites subjected to low loads. This study investigated the influence of added polypropylene, nylon, and carbon fibers on the mechanical properties of double setting alpha-tricalcium phosphate-based cement, using calcium phosphate cement added to an in situ polymerizable acrylamide-based system recently developed by the authors. Although the addition of fibers was found to reduce the compression strength of the double-setting calcium phosphate cement because of increased porosity, it strongly increased the cement's toughness (J(IC)) and tensile strength. The composites developed in this work, therefore, have a potential application in shapes subjected to flexure. PMID:12734819

dos Santos, Luís Alberto; Carrodéguas, Raúl Garcia; Boschi, Anselmo Ortega; Fonseca de Arruda, Antônio Celso

2003-05-01

246

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweigh cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems, Task 2: Review Russian Ultra-Lightweight Cement Literature, and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary surface pipe and intermediate casing cementing conditions historically encountered in the US and establishment of average design conditions for ULHS cements. Russian literature concerning development and use of ultra-lightweight cements employing either nitrogen or ULHS was reviewed, and a summary is presented. Quality control testing of materials used to formulate ULHS cements in the laboratory was conducted to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS. This protocol is presented and discussed. finally, results of initial testing of ULHS cements is presented along with analysis to establish cement performance design criteria to be used during the remainder of the project.

Fred Sabins

2001-01-15

247

Enhanced Biocompatibility of Porous Nitinol.  

PubMed

Porous Nitinol (PNT) has found vast applications in the medical industry as interbody fusion devices, synthetic bone grafts, etc. However, the tendency of the PNT to corrode is anticipated to be greater as compared to solid nitinol since there is a larger surface area in contact with body fluids. In such cases, surface preparation is known to play a major role in a material's biocompatibility. In an effort to check the effect of surface treatments on the in vitro corrosion properties of PNT, in this investigation, they were subjected to different surface treatments such as boiling in water, dry heating, and passivation. The localized corrosion resistance of alloys before and after each treatment was evaluated in phosphate buffer saline solution (PBS) using cyclic polarization tests in accordance with ASTM F 2129-08. PMID:19956797

Munroe, Norman; Pulletikurthi, Chandan; Haider, Waseem

2009-08-01

248

Enhanced Biocompatibility of Porous Nitinol  

NASA Astrophysics Data System (ADS)

Porous Nitinol (PNT) has found vast applications in the medical industry as interbody fusion devices, synthetic bone grafts, etc. However, the tendency of the PNT to corrode is anticipated to be greater as compared to solid nitinol since there is a larger surface area in contact with body fluids. In such cases, surface preparation is known to play a major role in a material’s biocompatibility. In an effort to check the effect of surface treatments on the in vitro corrosion properties of PNT, in this investigation, they were subjected to different surface treatments such as boiling in water, dry heating, and passivation. The localized corrosion resistance of alloys before and after each treatment was evaluated in phosphate buffer saline solution (PBS) using cyclic polarization tests in accordance with ASTM F 2129-08.

Munroe, Norman; Pulletikurthi, Chandan; Haider, Waseem

2009-08-01

249

Polycrystalline Silicon: a Biocompatibility Assay  

NASA Astrophysics Data System (ADS)

Polycrystalline silicon (poly-Si) layers were functionalized through the growth of biomimetic hydroxyapatite (HA) on their surface. HA is the mineral component of bones and teeth and thus possesses excellent bioactivity and biocompatibility. MG-63 osteoblast-like cells were cultured on both HA-coated and un-coated poly-Si surfaces for 1, 3, 5 and 7 days and toxicity, proliferation and cell morphology were investigated. The results revealed that the poly-Si layers were bioactive and compatible with the osteoblast-like cells. Nevertheless, the HA coating improved the cell interactions with the poly-Si surfaces based on the cell affinity to the specific chemical composition of the bone-like HA and/or to the higher HA roughness.

Pecheva, E.; Laquerriere, P.; Bouthors, Sylvie; Fingarova, D.; Pramatarova, L.; Hikov, T.; Dimova-Malinovska, D.; Montgomery, P.

2010-01-01

250

Polycrystalline Silicon: a Biocompatibility Assay  

SciTech Connect

Polycrystalline silicon (poly-Si) layers were functionalized through the growth of biomimetic hydroxyapatite (HA) on their surface. HA is the mineral component of bones and teeth and thus possesses excellent bioactivity and biocompatibility. MG-63 osteoblast-like cells were cultured on both HA-coated and un-coated poly-Si surfaces for 1, 3, 5 and 7 days and toxicity, proliferation and cell morphology were investigated. The results revealed that the poly-Si layers were bioactive and compatible with the osteoblast-like cells. Nevertheless, the HA coating improved the cell interactions with the poly-Si surfaces based on the cell affinity to the specific chemical composition of the bone-like HA and/or to the higher HA roughness.

Pecheva, E.; Fingarova, D.; Pramatarova, L.; Hikov, T. [Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia (Bulgaria); Laquerriere, P.; Bouthors, Sylvie [NSERM, ERM 0203 (labo des biomateriaux), IFR53, Reims (France); Dimova-Malinovska, D. [Central Laboratory of Solar Energy and New Energy Sources, Bulgarian Academy of Sciences, Sofia (Bulgaria); Montgomery, P. [1 Institut d'Electronique du Solide et des Systemes (InESS), UDS-CNRS, UMR 7163, 23 rue du Loess, 67037 Strasbourg (France)

2010-01-21

251

Ex vivo human trabecular bone model for biocompatibility evaluation of calcium phosphate composites modified with spray dried biodegradable microspheres.  

PubMed

Our aim was to study the suitability of the ex-vivo human trabecular bone bioreactor ZetOS to test the biocompatibility of calcium phosphate bone cement composites modified with spray dried, drug loaded microspheres. We hypothesized, that this bone bioreactor could be a promising alternative to in vivo assessment of biocompatibility in living human bone over a defined time period. Composites consisting of tetracycline loaded poly(lactic-co-glycolic acid) microspheres and calcium phosphate bone cement, were inserted into in vitro cultured human femora head trabecular bone and incubated over 30 days at 37°C in the incubation system. Different biocompatibility parameters, such as lactate dehydrogenase activity, alkaline phosphatase release and the expression of relevant cytokines, IL-1?, IL-6, and TNF-?, were measured in the incubation medium. No significant differences in alkaline phosphatase, osteocalcin, and lactate dehydrogenase activity were measured compared to control samples. Tetracycline was released from the microspheres, delivered and incorporated into newly formed bone. In this study we demonstrated that ex vivo biocompatibility testing using human trabecular bone in a bioreactor is a potential alternative to animal experiments since bone metabolism is still maintained in a physiological environment ex vivo. PMID:23568426

Schnieders, Julia; Gbureck, Uwe; Germershaus, Oliver; Kratz, Marita; Jones, David B; Kissel, Thomas

2013-04-09

252

Evaluation of four biodegradable, injectable bone cements in an experimental drill hole model in sheep.  

PubMed

Four cement applications were tested in this investigation. Two dicalcium phosphate dihydrate (DCPD-brushite) hydraulic cements, an apatite hydraulic fiber loaded cement, and a calcium sulfate cement (Plaster of Paris) were implanted in epiphyseal and metaphyseal cylindrical bone defects in sheep. The in vivo study was performed to assess the biocompatibility and bone remodeling of four cement formulations. After time periods of 2, 4, and 6 months, the cement samples were clinically and histologically evaluated. Histomorphometrically, the amount of new bone formation, fibrous tissue, and bone marrow and the area of remaining cement were measured. In all specimens, no signs of inflammation were detectable either macroscopically or microscopically. Cements differed mainly in their resorption time. Calcium sulfate was already completely resorbed at 2 months and showed a variable amount of new bone formation and/or fibrous tissue in the original drill hole over all time periods. The two DCPD cements in contrast were degraded to a large amount at 6 months, whereas the apatite was almost unchanged over all time periods. PMID:23680585

von Rechenberg, Brigitte; Génot, Oliver R; Nuss, Katja; Galuppo, Larry; Fulmer, Mark; Jacobson, Evan; Kronen, Peter; Zlinszky, Kati; Auer, Jörg A

2013-05-13

253

Cement-related burns.  

PubMed

Burns caused by prolonged contact of wet cement with skin are common in this country. Recent literature has highlighted other ways in which the use and manufacture of cement can lead to burn injuries, notably through explosion and contact with hot powder during manufacturing. These injuries are uncommon in this country and potentially very serious. Case studies are presented of two men injured in such a way in the same incident at a cement-manufacturing plant. PMID:8982549

Morley, S E; Humzah, D; McGregor, J C; Gilbert, P M

1996-12-01

254

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

Fred Sabins

2003-01-31

255

76 FR 76760 - Gray Portland Cement and Cement Clinker From Japan  

Federal Register 2010, 2011, 2012, 2013

...No. 731-TA-461 (Third Review)] Gray Portland Cement and Cement Clinker From...revocation of the antidumping duty order on gray Portland cement and cement clinker from...Publication 4281 (December 2011), entitled Gray Portland Cement and Cement Clinker...

2011-12-08

256

Nanocrystalline tetracalcium phosphate cement.  

PubMed

Calcium hydroxide cements can lack long-term stability and achieve sustained release by matrix-controlled diffusion of hydroxyl ions. Tetracalcium phosphate (TTCP) hydrolyzes slowly to form calcium hydroxide and a thin insoluble apatite layer that prevents further reaction. In this study, mechanical amorphization was used to create a setting calcium-hydroxide-releasing cement from TTCP. The effect of high-energy ball milling of TTCP on the mechanical properties of the cement was investigated. X-ray diffraction data were used to determine the phase composition of the set cements. An accelerated in vitro test compared pH of water after prolonged boiling of nanocrystalline TTCP cements and a calcium salicylate material. As milling time increased, cement compressive strength and degree of conversion increased. Hydroxyl ion release from the cement was comparable with that from a calcium salicylate material. This new cement system offers the antimicrobial potential of calcium salicylate materials combined with the long-term stability of insoluble apatite cements. PMID:15111637

Gbureck, U; Barralet, J E; Hofmann, M P; Thulí, R

2004-05-01

257

How polysulfone dialysis membranes containing polyvinylpyrrolidone achieve excellent biocompatibility?  

Microsoft Academic Search

Polysulfone (PS) dialysis membranes hydrophilized by blending polyvinylpyrrolidone (PVP) are well known to have excellent biocompatibility in clinical use. The objective of the present study is thus to clarify how PVP improves biocompatibility of PS membranes and furthermore to develop a patient-friendly PS dialysis membrane with higher biocompatibility. Biocompatibility based on both lactate dehydrogenase (LDH) activity and amount of protein

Masayo Hayama; Ken-ichiro Yamamoto; Fukashi Kohori; Kiyotaka Sakai

2004-01-01

258

Preclinical evaluation of strontium-containing bioactive bone cement.  

PubMed

Strontium (Sr) has become more attractive for orthopaedic applications as they can simultaneously stimulate bone formation and prevent bone loss. A Sr-containing bioactive bone cement (Sr-BC) has been designed to fix osteoporotic bone fracture. Sr is a trace element, so the safety of containing Sr is concerned when Sr-BC is implanted in human body. The preclinical assessment of biocompatibility of Sr-BC was conducted according to ISO 10993 standards. MTT assay showed that this bioactive bone cement was non-toxic to mouse fibroblasts, and it met the basic requirement for the orthopaedic implant. The three independent genetic toxicity studies including Ames, chromosome aberration and bone marrow micronucleus assays demonstrated absence of genotoxic components in Sr-BC, which reassured the safety concerns of this novel bone cement. The muscle implantation results in present study were also encouraging. The acute inflammation around the cement was observed at 1week post-implantation; however, no significant difference was observed between control and Sr-BC groups. These responses may be attributed to the presence of the foreign body, but the tissue healed after 12weeks implantation. In summary, the above preclinical results provide additional assurance for the safety of this implant. Sr-BC can be used as a potential alternative to the traditional bone cement. PMID:24094231

Li, Zhaoyang; Yuan, Ning; Lam, Raymond Wing Moon; Cui, Zhenduo; Yang, Xianjin; Lu, William Weijia

2013-07-20

259

Biocompatibility testing of branched and linear polyglycidol.  

PubMed

Polyglycidols are flexible hydrophilic polyethers that are potentially biocompatible polymers based on their similarities to the well-studied poly(ethyleneglycol). Polyglycidols can be prepared as branched or linear polymers by suitable synthetic methods. Biocompatibility testing of these polymers conducted in vitro as well as in vivo are reported here. The in vitro studies included hemocompatibility testing for effects on coagulation (PT and APTT), complement activation, red blood cell aggregation, and whole blood viscosity measurements. In vitro cytotoxicity experiments were also conducted. The results were compared with some of the common biocompatible polymers already in human use. Results from these studies show that polyglycidols are highly biocompatible. Hyperbranched polyglycidols were found to be well tolerated by mice even when injected in high doses. PMID:16529404

Kainthan, Rajesh Kumar; Janzen, Johan; Levin, Elena; Devine, Dana V; Brooks, Donald E

2006-03-01

260

Fluoride content and recharge ability of five glassionomer dental materials  

Microsoft Academic Search

BACKGROUND: The relationship between fluoride content and fluoride release for glass-ionomer cements is not well understood. The aim of this laboratory study was: to determine the fluoride concentrations at the surfaces of glass-ionomer materials with respect to different storage media and different pH environments; to examine the recharge ability of the materials after NaF immersion; and to assess the morphological

Dejan Lj Markovic; Bojan B Petrovic; Tamara O Peric

2008-01-01

261

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

Fred Sabins

2004-01-30

262

Pozzolan Cement Study.  

National Technical Information Service (NTIS)

This research study was to evaluate the performance of a Type 1P cement concrete pavement constructed on an experimental project as compared to a regular Type 1(B) cement concrete pavement. The sections were evaluated for strength, durability, skid resist...

S. M. Law M. Rasoulian

1979-01-01

263

Ultra-Lightweight Cement.  

National Technical Information Service (NTIS)

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. D...

F. Sabins

2003-01-01

264

SURFACE CHEMISTRY INFLUENCE IMPLANT BIOCOMPATIBILITY  

PubMed Central

Implantable medical devices are increasingly important in the practice of modern medicine. Unfortunately, almost all medical devices suffer to a different extent from adverse reactions, including inflammation, fibrosis, thrombosis and infection. To improve the safety and function of many types of medical implants, a major need exists for development of materials that evoked desired tissue responses. Because implant-associated protein adsorption and conformational changes thereafter have been shown to promote immune reactions, rigorous research efforts have been emphasized on the engineering of surface property (physical and chemical characteristics) to reduce protein adsorption and cell interactions and subsequently improve implant biocompatibility. This brief review is aimed to summarize the past efforts and our recent knowledge about the influence of surface functionality on protein:cell:biomaterial interactions. It is our belief that detailed understandings of bioactivity of surface functionality provide an easy, economic, and specific approach for the future rational design of implantable medical devices with desired tissue reactivity and, hopefully, wound healing capability.

Thevenot, Paul; Hu, Wenjing; Tang, Liping

2011-01-01

265

Biocompatibility of crystalline opal nanoparticles  

PubMed Central

Background Silica nanoparticles are being developed as a host of biomedical and biotechnological applications. For this reason, there are more studies about biocompatibility of silica with amorphous and crystalline structure. Except hydrated silica (opal), despite is presents directly and indirectly in humans. Two sizes of crystalline opal nanoparticles were investigated in this work under criteria of toxicology. Methods In particular, cytotoxic and genotoxic effects caused by opal nanoparticles (80 and 120 nm) were evaluated in cultured mouse cells via a set of bioassays, methylthiazolyldiphenyl-tetrazolium-bromide (MTT) and 5-bromo-2?-deoxyuridine (BrdU). Results 3T3-NIH cells were incubated for 24 and 72 h in contact with nanocrystalline opal particles, not presented significant statistically difference in the results of cytotoxicity. Genotoxicity tests of crystalline opal nanoparticles were performed by the BrdU assay on the same cultured cells for 24 h incubation. The reduction of BrdU-incorporated cells indicates that nanocrystalline opal exposure did not caused unrepairable damage DNA. Conclusions There is no relationship between that particles size and MTT reduction, as well as BrdU incorporation, such that the opal particles did not induce cytotoxic effect and genotoxicity in cultured mouse cells.

2012-01-01

266

Matrix control cementing slurry  

SciTech Connect

This patent describes a method of cementing a well bore. The method consists of 1.) mixing together at ambient temperatures at the well surface a hydraulic cement, water, in an effective amount to produce a pumpable slurry, and a polyvinyl acetate-polyvinyl alcohol polymer, which is insoluble in the slurry at ambient temperatures. The polymer has a greater than about 95 percent acetate groups converted to hydroxyl groups. The polymer is heated to actuable solubilization in the cement slurry at temperatures above about 120/sup 0/F. The solubilizing of the polyvinyl acetate-polyvinyl alcohol polymer in the slurry prior to the setting of the slurry by pumping the cement slurry to a desired location in the well bore. This action increases the temperature of the slurry; and 2.) allows the cement slurry to harden to a solid mass.

Arpenter, R.B.

1986-02-11

267

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

Fred Sabins

2002-01-23

268

Comparison of Calcium and Silicate Cement and Mineral Trioxide Aggregate Biologic Effects and Bone Markers Expression in MG63 Cells  

Microsoft Academic Search

Bone cell (MG63) biocompatibility and bone marker expression were compared after calcium and silicate base cement (CS) and mineral trioxide aggregate (MTA) treatment. X-ray diffraction was used to identify material surface structure, and tetrazolium bromide colorimetric assay was used to evaluate the cell viability. The relative mitogen activation protein kinase expression was compared with Western blot, and bone marker expression

Chih-Lin Chen; Tsui-Hsien Huang; Shinn-Jyh Ding; Ming-You Shie; Chia-Tze Kao

2009-01-01

269

Cement Evaluation Tool: A New Approach to Cement Evaluation  

Microsoft Academic Search

Cement bond logging achieves its greatest utility when it provides the production engineer with precise indications of cement strength and distribution around the casing. Zone isolation is of critical importance in production. Previous logging systems have yielded measures of cement bond that were circumferential averages of cement quality. These were difficult to interpret. Additionally, they were sensitive to the degree

Benoit Froelich; A. Dumont; Dennis Pittman; Bruno Seeman

1982-01-01

270

Injectable acrylic bone cements for vertebroplasty based on a radiopaque hydroxyapatite. Formulation and rheological behaviour.  

PubMed

The utilization of injectable acrylic bone cement is crucial to the outcome of vertebroplasty and kyphoplasty. However, only a few cements that are in clinical use today are formulated specifically for use in these procedures and even these formulations are not regarded as "ideal" injectable bone cements. The aim of this work is to prepare bioactive bone cements by adding strontium hydroxyapatite (SrHA) to a cement formulation based on polymethylmethacrylate. Thus, the cement combines the immediate mechanical support given by the setting of the acrylic matrix with optimum radiopacity and bioactivity due to the incorporation of the SrHA. Formulations of bioactive cement were prepared with 10 and 20 wt% of SrHA as synthesised and after a surface treatment with the monomer. Cements loaded with treated particles showed an enhancement of their handling properties, and hence, an improvement on their rheological behaviour, injectabilities and compressive parameters. Further experiments were also carried out to determine their bioactivity and biocompatibility and results appear in other publication. PMID:18704657

Hernández, L; Gurruchaga, M; Goñi, I

2008-08-14

271

Premixed macroporous calcium phosphate cement scaffold  

PubMed Central

Calcium phosphate cement (CPC) sets in situ to form resorbable hydroxyapatite and is promising for orthopaedic applications. However, it requires on-site powder-liquid mixing during surgery, which prolongs surgical time and raises concerns of inhomogeneous mixing. The objective of this study was to develop a premixed CPC scaffold with macropores suitable for tissue ingrowth. To avoid the on-site powder-liquid mixing, the CPC paste was mixed in advance and did not set in storage; it set only after placement in a physiological solution. Using 30% and 40% mass fractions of mannitol porogen, the premixed CPC scaffold with fibers had flexural strength (mean ± sd; n = 5) of (3.9 ± 1.4) MPa and (1.8 ± 0.8) MPa, respectively. The scaffold porosity reached (68.6 ± 0.7)% and (74.7 ± 1.2)%, respectively. Osteoblast cells colonized in the surface macropores of the scaffold and attached to the hydroxyapatite crystals. Cell viability values for the premixed CPC scaffold was not significantly different from that of a conventional non-premixed CPC known to be biocompatible (P > 0.1). In conclusion, using fast-dissolving porogen and slow-dissolving fibers, a premixed macroporous CPC scaffold was developed with strength approaching the reported strengths of sintered porous hydroxyapatite implants and cancellous bone, and non-cytotoxicity similar to a biocompatible non-premixed CPC.

Carey, Lisa E.; Simon, Carl G.

2009-01-01

272

In Vitro and in Vivo Characteristics of Fluorapatite-Forming Calcium Phosphate Cements  

PubMed Central

This study reports for the first time in vitro and in vivo properties of fluorapatite (FA)-forming calcium phosphate cements (CPCs). The experimental cements contained from (0 to 3.1) mass % of F, corresponding to presence of FA at levels of approximately (0 to 87) mass %. The crystallinity of the apatitic cement product increased greatly with the FA content. When implanted subcutaneously in rats, the in vivo resorption rate decreased significantly with increasing FA content. The cement with the highest FA content was not resorbed in soft tissue, making it the first known biocompatible and bioinert CPC. These bioinert CPCs might be useful for applications where slow or no resorption of the implant is required to achieve the desired clinical outcome.

Takagi, Shozo; Frukhtbeyn, Stan; Chow, Laurence C.; Sugawara, Akiyoshi; Fujikawa, Kenji; Ogata, Hidehiro; Hayashi, Makoto; Ogiso, Binnai

2010-01-01

273

Bone cement implantation syndrome.  

PubMed

Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, cardiac arrhythmias, increased pulmonary vascular resistance and cardiac arrest. It is a known cause of morbidity and mortality in patients undergoing cemented orthopaedic surgeries. The rarity of the condition as well as absence of a proper definition has contributed to under-reporting of cases. We report a 59-year-old woman who sustained fracture of the neck of her left femur and underwent an elective hybrid total hip replacement surgery. She collapsed during surgery and was revived only to succumb to death twelve hours later. Post mortem findings showed multiorgan disseminated microembolization of bone marrow and amorphous cement material. PMID:23817399

Razuin, R; Effat, O; Shahidan, M N; Shama, D V; Miswan, M F M

2013-06-01

274

Cell cultures in microsystems: biocompatibility aspects.  

PubMed

Bio-Micro-Electro-Mechanical Systems (BioMEMS) are a new tool in life sciences, supporting cell biology research by providing reproducible and miniaturized experimental platforms. In order to cultivate cells in such systems, appropriate microenvironmental conditions are required. Due to the multitude and variety of microbioreactors and cultivated cell types available, standardized cell handling methods and comprehensive biocompatibility data are sparse. The bioreactor developed at Ilmenau University of Technology features BioMEMS consisting of silicon, glass, and polymers, supplied by peripheral components. To verify the system's suitability for cell cultivation, it was necessary to prove whether materials and surfaces are biocompatible. Custom-tailored biocompatibility test procedures along with adequate cell seeding and handling methods had to be developed. According to this, proper positive and negative control samples had to be identified. The cultivation procedures were carried out using osteoblast-like murine fibroblasts (MC3T3-E1) and primary human osteoblasts (hOB). We could provide evidence that cultivation of these cells in our BioMEMS is feasible. In this context the relevant materials and the system's structure can be regarded as to be biocompatible. We could show that cell seeding and handling methods possess a strong impact on growth, development, and cellular activity of cell cultures in BioMEMS. Statistical biocompatibility data for the materials used is given. PMID:20872818

Fischer, R; Steinert, S; Fröber, U; Voges, D; Stubenrauch, M; Hofmann, G O; Witte, H

2010-11-30

275

Nanocrystalline Tetracalcium Phosphate Cement  

Microsoft Academic Search

Calcium hydroxide cements can lack long-term stability and achieve sustained release by matrix-controlled diffusion of hydroxyl ions. Tetracalcium phosphate (TTCP) hydrolyzes slowly to form calcium hydroxide and a thin insoluble apatite layer that prevents further reaction. In this study, mechanical amorphization was used to create a setting calcium-hydroxide-releasing cement from TTCP. The effect of high-energy ball milling of TTCP on

U. Gbureck; J. E. Barralet; M. P. Hofmann

2004-01-01

276

Highly piezoelectric Biocompatible and Soft Composite Fibers  

NASA Astrophysics Data System (ADS)

We report the fabrication of highly piezoelectric biocompatible soft fibers containing Barium Titanate (BT) ferroelectric ceramic particles dispersed in electrospun poly lactic acid (PLA). These fibers form mats that have two orders of magnitude larger piezoelectric constant per weight than single crystal barium titanate films. We demonstrate that the observed super-piezoelectricity results from the electrospinning induced polar alignment of the ferroelectric particles and the increased surface area compared to single crystal films. Due to the biocompatibility of PLA that encases the ferroelectric particles, these mats can be applied even in biological applications such as bio-sensors, artificial muscles and energy harvesting devices.

Jakli, Antal; Morvan, Jason; Buyuktanir, Ebru; West, John

2012-02-01

277

Highly piezoelectric biocompatible and soft composite fibers  

NASA Astrophysics Data System (ADS)

We report the fabrication of highly piezoelectric biocompatible soft fibers containing barium titanate ferroelectric ceramic particles dispersed in electrospun poly lactic acid (PLA). These fibers form mats that have two orders of magnitude larger piezoelectric constant per weight than single crystal barium titanate films. We propose that the observed apparent piezoelectricity results from the electrospinning induced polar alignment of the ferroelectric particles that pole the fibers similar to ferroelectret polymer foams that are poled by corona discharge. Due to the biocompatibility of PLA that encases the ferroelectric particles, these mats can be used in biological applications such as bio-sensors, artificial muscles, and energy harvesting devices.

Morvan, J.; Buyuktanir, E.; West, J. L.; Jákli, A.

2012-02-01

278

Characterization of modified calcium-silicate cements exposed to acidic environment  

SciTech Connect

Portland cement which is used as a binder in concrete in the construction industry has been developed into a biomaterial. It is marketed as mineral trioxide aggregate and is used in dentistry. This material has been reported to be very biocompatible and thus its use has diversified. The extended use of this material has led to developments of newer versions with improved physical properties. The aim of this study was to evaluate the effect of acidic environments found in the oral cavity on fast setting calcium silicate cements with improved physical properties using a combination of techniques. Two fast setting calcium silicate cements (CSA and CFA) and two cement composites (CSAG and CFAG) were assessed by subjecting the materials to lactic acid/sodium lactate buffer gel for a period of 28 days. At weekly intervals the materials were viewed under the tandem scanning confocal microscope (TSM), and scanning electron microscope (SEM). The two prototype cements exhibited changes in their internal chemistry with no changes in surface characteristics. Since the changes observed were mostly sub-surface evaluation of surface characteristics of cement may not be sufficient in the determination of chemical changes occurring. - Research Highlights: {yields} An acidic environment affects modified fast setting calcium silicate-based cements. {yields} No surface changes are observed in acidic environment. {yields} An acidic environment causes sub-surface changes in the material chemistry which are only visible in fractured specimens. {yields} A combination of techniques is necessary in order to evaluate the chemical changes occurring.

Camilleri, Josette, E-mail: josette.camilleri@um.edu.mt

2011-01-15

279

Preparation of epoxy-SiO2 hybrid sol-gel material for bone cement.  

PubMed

An organic-inorganic hybrid material, epoxy-SiO(2), was prepared by incorporating epoxy structure units covalently into a SiO(2) glass network via the sol-gel approach. The precursor was obtained by the reaction of diglycidyl ether of bisphenol A (DGEBA) with 3-aminopropyl trimethoxysilane (APTS). The precursor was then hydrolyzed and co-condensated with tetraethyl orthosilicate (TEOS) in tetrahydrofuran (THF) at room temperature to yield epoxy-SiO(2) hybrid sol-gel material having a 50 wt % SiO(2) content. Thermal properties of the hybrid material were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The hybrid sol-gel material epoxy-SiO(2) was the solid, powder component of bone cement. The liquid component contains bis-phenol-A glycidyl methacrylate (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), and methyl methacrylate (MMA) with 25, 55, and 20 vol %, respectively. We discuss the comparison between the new epoxy-SiO(2) bone cement and the commercial Simplex P bone cement. Mechanical properties such as Young's modulus, compressive strength, hardness, and impact strength of the new epoxy-SiO(2) bone cement exceeded those of Simplex P bone cement. The tensile and bending strengths of the new epoxy-SiO(2) bone cement were approximately the same as those of Simplex P bone cement. In order to evaluate the biocompatibility of the new bone cement, an MTT test and optical microscopy were conducted in cell culture. Results indicated that the new epoxy-SiO(2) bone cement exhibits very low cytotoxicity compared with Simplex P bone cement. PMID:12483706

Yang, Jen Ming; Shih, Chun Hsiung; Chang, Chen-Nen; Lin, Feng Huei; Jiang, Jian Ming; Hsu, Ying Gev; Su, Wen Yu; See, Lai Chu

2003-01-01

280

Orthodontic band retention on primary molar stainless steel crowns  

Microsoft Academic Search

The retention of orthodontic bands cemented on primary molar stainless steel crowns (SSC) was studied in vitro. Unitek maxillary and mandibular 1st and 2nd primary molar SSC were fitted with one of four commonly used orthodontic bands (Unitek regular, Unitek narrow, Rocky Mountain, or custom bands made from SSC) using glass ionomer cement. The cemented samples were tested for their

Randy L. Beemer; Jack L. Ferracane; Harold E. Howard

1993-01-01

281

Differential biocompatibility of carbon nanotubes and nanodiamonds  

Microsoft Academic Search

Carbon nanomaterials are being produced in increasingly larger quantities for many applications due to their novel characteristics such as enhanced thermal, electrical, mechanical, and biological properties. However, there is a lack of data on biological interactions to assess their biocompatibility before they will be accepted as non-toxic in industrial or biomedical arenas. In the present study, we examined both neuronal

Amanda M. Schrand; Liming Dai; John J. Schlager; Saber M. Hussain; Eiji Osawa

2007-01-01

282

Preparation of biocompatible membranes by electrospinning  

Microsoft Academic Search

In this study, the electrospinning technique was applied to fabricate biocompatible membranes composed of PLLA (poly-L-lactic acid) and chitosan. With high porosity and interconnected structure, the electrospun membranes were suitable scaffolds for cell or tissue growth. In preparations, injection rate, polymer concentration and applied voltage were varied to investigate their effects on electrospun fibers. The morphology of the electrospun membranes

Jing-Wen Chen; Kuo-Feng Tseng; Swary Delimartin; Cheng-Kang Lee; Ming-Hua Ho

2008-01-01

283

In vitro studies of carbon nanotubes biocompatibility  

Microsoft Academic Search

Cellular tests have been applied to study the biocompatibility of high purity multiwalled carbon nanotubes (MWNTs). The viability of fibroblasts, osteoblasts and osteocalcin concentrations in osteoblasts cultures in the presence of nanotubes has been examined, as well as the degree of cells stimulation, based on the amount of released collagen type I, IL-6 and oxygen free radicals. The high level

J. Ch?opek; B. Czajkowska; B. Szaraniec; E. Frackowiak; K. Szostak; F. Béguin

2006-01-01

284

Strategies to Improve Silicone Elastomer Biocompatibility  

Microsoft Academic Search

Silicone polymers, particularly elastomers, are widely used biomaterials in applications as diverse as wound dressings, hydrocephalic shunts, breast implants and intraocular lenses. 1 While many of the properties of silicones are particularly useful for these applications, including transparency, facile control of shape, high oxygen permeability and good biocompatibility, there can be issues with these polymers in biomaterials applications. Silicone polymers,

Michael A. Brook; Heather D. Sheardown; Alison Holloway; d Shao; Ken Ng; Johan Alauzun

285

Biocompatibility evaluation of 3 facial silicone elastomers.  

PubMed

The failure of facial prostheses is caused by limitations in the properties of existing materials, especially the biocompatibility. This study aimed to evaluate the biocompatibility of maxillofacial silicones in subcutaneous tissue of rats. Thirty Wistar rats received subcutaneous implants of 3 maxillofacial silicone elastomers (LIM 6050, MDX 4-4210, and industrial Silastic 732 RTV). A histomorphometric evaluation was conducted to analyze the biocompatibility of the implants. Eight areas of 60.11 mm(2) from the surgical pieces were analyzed. Mesenchymal cells, eosinophils, and foreign-body giant cells were counted. Data were submitted to analysis of variance and Tukey test. Initially, all implanted materials exhibited an acceptable tissue inflammatory response, with tissue reactions varying from light to moderate. Afterward, a fibrous capsule around the silicone was observed. The silicones used in the current study presented biocompatibility and can be used for implantation in both medical and dental areas. Their prosthetic indication is conditioned to their physical properties. Solid silicone is easier to adapt and does not suffer apparent modifications inside the tissues. PMID:21558944

França, Diurianne Caroline Campos; de Castro, Alvimar Lima; Soubhia, Ana Maria Pires; Tucci, Renata; de Aguiar, Sandra Maria Herondina Coelho Ávila; Goiato, Marcelo Coelho

2011-05-01

286

ULTRA-LIGHTWEIGHT CEMENT  

SciTech Connect

The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

Fred Sabins

2001-10-23

287

Cement composition and method of cement casing in a well  

SciTech Connect

A novel cement composition for the preparation of a novel aqueous slurry useful in cementing casing in the borehole of a well comprising cement, a hydroxyethylcellulose ether having a critical viscosity or a mixture of a hydroxyethylcellulose ether having a critical viscosity and of a hydroxypropylcellulose ether having a critical viscosity and a dispersant.

Baker, W.S.; Harrison, J.J.

1984-07-31

288

Cement composition and method of cement casing in a well  

SciTech Connect

A novel cement composition for the preparation of a novel aqueous slurry useful in cementing casing in the borehole of a well comprising cement, a hydroxyethylcellulose ether or a mixture of a hydroxyethylcellulose ether and a hydroxypropylcellulose ether a polysaccharide produced as a result of microbial action and a dispersant.

Baker, W.S.; Harrison, J.J.

1984-07-31

289

Advanced Cements for Geothermal Wells.  

National Technical Information Service (NTIS)

Using the conventional well cements consisting of the calcium silicate hydrates and calcium aluminum silicate hydrates for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanical...

T. Sugama

2006-01-01

290

Lime Silico-Phosphate Cement.  

National Technical Information Service (NTIS)

A quick setting lime silico-phosphate cement prepared by reacting Wollastonite (CaSiO3) and buffered phosphoric acid is described. The cement has particular utility in highway patching operations. (Author)

C. E. Semler

1972-01-01

291

The hydration of dental cements.  

PubMed

A study was made of the hydration of dental cements, water being classified as "non-evaporable" and "evaporable". The ratio of these two types of water was found to vary greatly among different cement types, being lesser in zinc oxide and ionic polymer cements and greater in ion-leachable glass and phosphoric acid cements. The cement with the least "non-evaporable" water, i.e., showing least hydration (the zinc polycarboxylate cement), had the lowest strength and modulus and the greatest deformation at failure. A linear relationship was found to exist between strength and the degree of hydration of dental cements. All the cements were found to become more highly hydrated and stronger as they aged. PMID:284040

Wilson, A D; Paddon, J M; Crisp, S

1979-03-01

292

Well cementing process  

SciTech Connect

A process is described for improved bonding in a well system between cement, and well tubular members and the formation about the well bore at a pay zone, the steps comprising: (a) displacing at turbulent flow conditions drilling fluid materials, including mud, solids and filter cake, from the annulus between the tubular members and formation by circulating therein a slug of concentrate consisting essentially of a water-free mixture of surfactant and alcohol; and (b) following the slug of concentrate with an aqueous fluid cement whereby the slug of concentrate removes displaceable drilling fluid materials from the annulus at the pay zone but leaving some residual filter cake on the formation, and the well tubular members and residual filter cake both residing in a surface water-wetted condition after passage of the slug whereby hardening of the cement produces an improved bonding to both the well tubular members and the formation at the pay zone.

Oliver, J.E. Jr.; Singer, A.M.

1983-05-13

293

Research of magnesium phosphosilicate cement  

Microsoft Academic Search

Magnesium phosphosilicate cement (MPSC) is a novel phosphate bonded cement, which consists mainly of magnesia, phosphate and silicate minerals. The traditional magnesium phosphate cements (MPCs) usually composed by ammonium phosphate, and gaseous ammonia will emit during mixing and in service. There is no noxious ammonia released from MPSC, furthermore, it can recycle a large volume of the non-hazardous waste. The

Zhu Ding

2005-01-01

294

Cement Mason's Curriculum. Instructional Units.  

ERIC Educational Resources Information Center

To assist cement mason instructors in providing comprehensive instruction to their students, this curriculum guide treats both the skills and information necessary for cement masons in commercial and industrial construction. Ten sections are included, as follow: related information, covering orientation, safety, the history of cement, and applying…

Hendirx, Laborn J.; Patton, Bob

295

Study of Barnacle Cement.  

National Technical Information Service (NTIS)

Gross anatomical studies were done on the giant barnacle Balanus nubilis. This work was aimed at finding the site of cement production and its internal flow path. The internal flow path is a tubular network in the basal mass that communicates with the rad...

D. Lockhart K. Walker T. King R. Keller N. F. Cardarelli

1968-01-01

296

Gentamicin in bone cement  

PubMed Central

Objectives The objective of this study is to determine an optimal antibiotic-loaded bone cement (ALBC) for infection prophylaxis in total joint arthroplasty (TJA). Methods We evaluated the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with vancomycin, teicoplanin, ceftazidime, imipenem, piperacillin, gentamicin, and tobramycin against methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staph. aureus (MRSA), coagulase-negative staphylococci (CoNS), Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Standardised cement specimens made from 40 g PMMA loaded with 1 g antibiotics were tested for elution characteristics, antibacterial activities, and compressive strength in vitro. Results The ALBC containing gentamicin provided a much longer duration of antibiotic release than those containing other antibiotic. Imipenem-loading on the cement had a significant adverse effect on the compressive strength of the ALBC, which made it insufficient for use in prosthesis fixation. All of the tested antibiotics maintained their antibacterial properties after being mixed with PMMA. The gentamicin-loaded ALBC provided a broad antibacterial spectrum against all the test organisms and had the greatest duration of antibacterial activity against MSSA, CoNS, P. aeruginosa and E. coli. Conclusion When considering the use of ALBC as infection prophylaxis in TJA, gentamicin-loaded ALBC may be a very effective choice. Cite this article: Bone Joint Res 2013;2:220–6.

Chang, Y.; Tai, C-L.; Hsieh, P-H.; Ueng, S. W. N.

2013-01-01

297

A new and evolving paradigm for biocompatibility.  

PubMed

We propose that the mechanical property of the interface between an implant and its surrounding tissues is critical for the host response and the performance of the device. The interfacial mechanics depends on several different factors related to the physical shape of the device and its surface as well as properties of the host tissue and the loading conditions of the device and surrounding tissue. It seems plausible that the growth of the fibrotic tissue to support mechanical loads is governed by the same principles as depicted by Wolfs' Law for bone. Of course, biocompatibility will have different implications depending on which vantage point we look at the host-material interface. Another implication is that only limited aspects of biocompatibility is measurable with current in vitro tests and that the elicited host response in vivo models remains crucial for evaluation of medical devices and tissue engineering constructs. PMID:18038399

Hilborn, Jöns; Bjursten, Lars M

298

Biocompatibility in hemodialysis: clinical relevance in 1995.  

PubMed

Hemodialysis therapy for end-stage renal disease is still empirical even after more than 30 years of experience. Although long-term survival can now be assured in selected patients, clinical results tend to be disappointing. Hemodialysis therapy needs to be improved. Zealots of the biocompatibility school believe that this improvement will come from reducing undesirable consequences of blood membrane interaction, particularly complement activation. However, there is controversy over the clinical meaningfulness of biocompatibility when exclusively related to blood membrane interactions. Another dimension needs to be added, namely ultrapure dialysate to avoid subclinical chronic effects of activation of the cytokine cascade by bacterial fragments present in dialysate. While the pathogenesis of acute anaphylactoid reactions are understood and largely preventable, the relation of the chronic syndromes such as amyloidosis to the use of a particular membrane remain unproven. Prospective studies that will occupy at least a decade will be necessary to decide these issues. PMID:7625916

Shaldon, S; Koch, K M

1995-05-01

299

A biocompatible magnetic film: synthesis and characterization  

PubMed Central

Background Biotechnology applications of magnetic gels include biosensors, targeted drug delivery, artificial muscles and magnetic buckles. These gels are produced by incorporating magnetic materials in the polymer composites. Methods A biocompatible magnetic gel film has been synthesized using polyvinyl alcohol. The magnetic gel was dried to generate a biocompatible magnetic film. Nanosized iron oxide particles (?-Fe2O3, ~7 nm) have been used to produce the magnetic gel. Results The surface morphology and magnetic properties of the gel films were studied. The iron oxide particles are superparamagnetic and the gel film also showed superparamagnetic behavior. Conclusion Magnetic gel made out of crosslinked magnetic nanoparticles in the polymer network was found to be stable and possess the magnetic properties of the nanoparticles.

Chatterjee, Jhunu; Haik, Yousef; Chen, Ching Jen

2004-01-01

300

Bone regeneration with glass ceramic implants and calcium phosphate cements in a rabbit cranial defect model.  

PubMed

Hydroxyapatite cement (BoneSource®) and brushite calcium phosphate cement (chronOS™ Inject) were tested for fixation of glass ceramic implants (Bioverit®) in experimentally created cranial defects in 24 adult New Zealand White rabbits. Aim of the in vivo study was to assess and compare the biocompatibility and osseointegration of the implanted materials. Macroscopic and histological evaluations were performed 1 month, 3 months, and 6 months postoperatively. All implanted materials were well tolerated by the surrounding tissue. Both bone cements exhibited osteoconductive properties. Differences could be detected regarding to the rates of cement resorption and new bone formation. The brushite cement was resorbed faster than the hydroxyapatite cement. The chronOS™ Inject samples exhibited a higher rate of connective tissue formation and an insufficient osseointegration. BoneSource® was replaced by bone with minimal invasion of connective tissue. New bone formation occurred faster compared to the chronOS™ Inject group. Bioverit® implants fixed with BoneSource® were successfully osseointegrated. PMID:20859655

Schneider, Gerlind; Blechschmidt, Karin; Linde, Dirk; Litschko, Peter; Körbs, Thomas; Beleites, Eggert

2010-09-22

301

Laser microjoining of dissimilar and biocompatible materials  

NASA Astrophysics Data System (ADS)

Micro-joining and hermetic sealing of dissimilar and biocompatible materials is a critical issue for a broad spectrum of products such as micro-electronics, micro-optical and biomedical products and devices. Today, biocompatible titanium is widely applied as a material for orthopedic implants as well as for the encapsulation of implantable devices such as pacemakers, defibrillators, and neural stimulator devices. Laser joining is the process of choice to hermetically seal such devices. Laser joining is a contact-free process, therefore minimizing mechanical load on the parts to be joined and the controlled heat input decreases the potential for thermal damage to the highly sensitive components. Laser joining also offers flexibility, shorter processing time and higher quality. However, novel biomedical products, in particular implantable microsystems currently under development, pose new challenges to the assembly and packaging process based on the higher level of integration, the small size of the device's features, and the type of materials and material combinations. In addition to metals, devices will also include glass, ceramic and polymers as biocompatible building materials that must be reliably joined in similar and dissimilar combinations. Since adhesives often lack long-term stability or do not meet biocompatibility requirements, new joining techniques are needed to address these joining challenges. Localized laser joining provides promising developments in this area. This paper describes the latest achievements in micro-joining of metallic and non-metallic materials with laser radiation. The focus is on material combinations of metal-polymer, polymer-glass, metal-glass and metal-ceramic using CO2, Nd:YAG and diode laser radiation. The potential for applications in the biomedical sector will be demonstrated.

Bauer, Ingo; Russek, Ulrich A.; Herfurth, Hans J.; Witte, Reiner; Heinemann, Stefan; Newaz, Golam; Mian, A.; Georgiev, D.; Auner, Gregory W.

2004-07-01

302

Synthesis of biocompatible surfaces by nanotechnology methods  

Microsoft Academic Search

The modification of the surface of low-density polyethylene (LDPE) and polyurethane (PU) by means of the pulsed ion-plasma\\u000a deposition of nanostructural carbon coatings at 20–60°C has been studied. The effect of this low-temperature treatment on\\u000a the biocompatibility of the LDPE and PU has been assessed. Optimum technological parameters for the formation of mosaic carbon\\u000a nanostructures with a thickness of 0.3–15

A. P. Alekhin; G. M. Boleiko; S. A. Gudkova; A. M. Markeev; A. A. Sigarev; V. F. Toknova; A. G. Kirilenko; R. V. Lapshin; E. N. Kozlov; D. V. Tetyukhin

2010-01-01

303

Biocompatibility of a physiological pressure sensor  

Microsoft Academic Search

A newly developed fiber optic micropressure sensor was evaluated for biocompatibility using the International Organization for Standardization (ISO) test standard 10993-6. The test material and an inert control (fused silica glass) were tested in New Zealand white rabbits. Four test specimens were implanted in the paravertebral muscles on one side of the spine about 2–5 cm from the mid-line and

Chao Yang; Chunfeng Zhao; Lester Wold; Kenton R. Kaufman

2003-01-01

304

Biocompatibility of prosthetic meshes in abdominal surgery  

Microsoft Academic Search

Surgical meshes today represent a group of implants mainly used for hernia repair. Modern hernia surgery is no longer imaginable\\u000a without the application of these special biomaterials leading to millions of implantations each year worldwide. Because clinical\\u000a trials are insufficient to evaluate the distinct effects of modified mesh materials in regard to tissue biocompatibility and\\u000a functionality, a basic understanding of

Marcel Binnebösel; Klaus T. von Trotha; Petra Lynen Jansen; Joachim Conze; Ulf P. Neumann; Karsten Junge

2011-01-01

305

In vivo disintegration of four different luting agents.  

PubMed

The purpose of this study was to evaluate the disintegration of luting agents. An intraoral sample holder was made having four holes of 1.4?mm diameter and 2?mm depth. The holder was soldered onto the buccal surface of an orthodontic band, which was cemented to the first upper molar in 12 patients, average age 26 years. The holes were filled with a zinc phosphate (Phosphate Kulzer), a glass ionomer (Ketac Cem), a resin-modified-glass ionomer (Fuji Plus), and a resin cement (Calibra). Impressions were made at baseline, and 6, 12, and 18 months from which epoxy replicas were made, which were scanned with an optical scanner. Total volume loss was calculated. The rank order of mean volume loss was as follows: Phosphate cement > Ketac Cem = Fuji Plus = Calibra. Cement type and time had statistically significant effects on volume loss of cements (P < 0.001). Under in vivo conditions, zinc phosphate cement disintegrated the most, whereas no significant difference was observed for glass ionomer and resin-based cements. As intraoral conditions are considerably less aggressive than experimental laboratory conditions, the erosion behavior of glass ionomer cement was found to be similar to the resin-based cements in contradiction to previous laboratory results. PMID:22007219

Gemalmaz, Deniz; Pameijer, Cornelis H; Latta, Mark; Kuybulu, Ferah; Alcan, Toros

2011-10-05

306

In Vivo Disintegration of Four Different Luting Agents  

PubMed Central

The purpose of this study was to evaluate the disintegration of luting agents. An intraoral sample holder was made having four holes of 1.4?mm diameter and 2?mm depth. The holder was soldered onto the buccal surface of an orthodontic band, which was cemented to the first upper molar in 12 patients, average age 26 years. The holes were filled with a zinc phosphate (Phosphate Kulzer), a glass ionomer (Ketac Cem), a resin-modified-glass ionomer (Fuji Plus), and a resin cement (Calibra). Impressions were made at baseline, and 6, 12, and 18 months from which epoxy replicas were made, which were scanned with an optical scanner. Total volume loss was calculated. The rank order of mean volume loss was as follows: Phosphate cement > Ketac Cem = Fuji Plus = Calibra. Cement type and time had statistically significant effects on volume loss of cements (P < 0.001). Under in vivo conditions, zinc phosphate cement disintegrated the most, whereas no significant difference was observed for glass ionomer and resin-based cements. As intraoral conditions are considerably less aggressive than experimental laboratory conditions, the erosion behavior of glass ionomer cement was found to be similar to the resin-based cements in contradiction to previous laboratory results.

Gemalmaz, Deniz; Pameijer, Cornelis H.; Latta, Mark; Kuybulu, Ferah; Alcan, Toros

2012-01-01

307

A review of orthodontic cements and adhesives  

Microsoft Academic Search

Dental cements and resins are used intraorally to secure fixed orthodontic devices. Although cements are still used, the popularity of resin and resin-cement hybrid materials is increasing because of their improved physical properties and low solubility in oral fluids. Some cements bond chemically to enamel, but bond strengths are low because cements are brittle and fracture cohesively. Resin adhesives penetrate

Nels Ewoldsen; Richard S. Demke

2001-01-01

308

Cemented tungsten carbide pneumoconiosis.  

PubMed

An autopsy case of cemented tungsten carbide pneumoconiosis, the first lethal case in our country, is presented. A 28-year-old woman, who had been engaged in grinding presintered metallic matrix for four years, developed respiratory symptoms. X-ray examinations were indicative of interstitial pulmonary fibrosis. Corticosteroid therapy revealed only little effect. She expired five years after the onset of the symptoms. Postmortem examination showed nonspecific interstitial pneumonitis resulting in marked lung fibrosis. Ultrastructurally, crystals were observed in cytoplasm of presumable macrophages in the fibrotic lung tissue. Electron probe microanalysis of the lung tissue showed the presence of tungsten and other constituents of tungsten carbide except for cobalt. Metal analysis demonstrated a large amount of tungsten in the lung. Cobalt was detected tenfold of the normal value in the bone. In pathogenesis of the pneumoconiosis in the cemented tungsten carbide workers, toxicity of cobalt is most suspectable, and in addition, individual susceptibility may be also important. PMID:735823

Kitamura, H; Kitamura, H; Tozawa, T; Kimula, Y

1978-11-01

309

Cementing oil and gas wells  

SciTech Connect

This patent describes a method for cementing a wellbore penetrating an earth formation to which a conduit extends, the wellbore having a space occupied by a fluid composition to be converted to cement for cementing the space to form a seal between spaced apart points in the formation. It comprises providing means for adding cementitious material and a dispersant to the fluid, circulating the fluid and adding the cementitious material and the dispersant to a quantity of the fluid in predetermined proportions to form a settable cement composition comprising a major portion of the drilling fluid in the well as it was drilled; and water; a lesser proportion of dry cementitious material; a minor amount of a dispersant that does not effect a satisfactory set cement within an acceptable time interval; and a compatible accelerator selected from the class consisting of acetic acid; the first four carbon esters thereof; and acedamide and filling the wellbore with the cement composition.

Bloys, J.B.; Wilson, W.N.; Bradshaw, R.D.

1991-08-13

310

Calcium-phosphate-silicate composite bone cement: self-setting properties and in vitro bioactivity.  

PubMed

In this study, a novel low temperature setting calcium phosphate-silicate cement was obtained by mixing CaHPO(4) x 2H(2)O (DCPD) and Ca(3)SiO(5) (C(3)S) with 0.75 M sodium phosphate buffers (pH = 7.0) as liquid phase. The self-setting properties of the obtained DCPD/C(3)S paste with liquid to powder ratio (L/P) of 0.6 ml/g, such as setting times, injectability, degradability and compressive strength were investigated and compared with that of DCPD/CaO cement system. The results indicated that, with the weight ratio of C(3)S varied from 20% to 40%, the workable DCPD/C(3)S pastes could set within 20 min, and the hydrated cement showed significantly higher compressive strength (around 34.0 MPa after 24 h) than that of the DCPD/CaO cement system (approximately 10.0 MPa). Furthermore, the in vitro pH value of the cements was investigated by soaking in simulated body fluid (SBF) for 12 h, and the result indicated that the DCPD/C(3)S did not induce significant increase or decrease of pH value in SBF. Additionally, the composite cement possesses better ability to support and stimulate cell proliferation than the DCPD/CaO cement. With good hydraulic properties, improved biocompatibility and moderate degradability, the novel DCPD/C(3)S bone cement may be a potential candidate as bone substitute. PMID:19034622

Huan, Zhiguang; Chang, Jiang

2008-11-26

311

Biomimetic Calcium-Silicate Cements Support Differentiation Of Human Orofacial Mesenchymal Stem Cells  

PubMed Central

Introduction Human orofacial bone mesenchymal stem cells (OFMSCs) from maxilla and mandible have robust osteogenic regenerative properties based on our previous reports that demonstrate phenotypic and functional differences between jaw and axial bone mesenchymal stem cells in same individuals. Furthermore, a combination of OFMSCs with bioactive calcium-releasing cements can potentially improve OFMSC multi-lineage differentiation capacity, but biocompatibility of calcium silicate cements with OFMSCs is still unclear. We tested the hypothesis that material extracts of calcium-releasing calcium-silicate cements support biomimetic microenvironment for survival and differentiation of human OFMSCs. Methods Two experimental calcium-silicate cements 1) calcium-silicate mineral powder (wTC) containing di- and tricalcium-silicate, calcium sulphate, and calcium chloride and 2) wTC doped with alpha-tricalcium phosphate (wTC-?TCP) were designed and prepared. Cement setting times were assessed by Gilmore needles, ability to release calcium and hydroxyl ions was assessed by potentiometric methods and OFMSC attachment to calcium-silicate discs was assessed. Calcium-silicate material extracts were tested for ability to support OFMSCs survival and in vitro/in vivo differentiation. Results Fewer OFMSCs attached to calcium-silicate discs relative to tissue culture plastic (p=0.001). Extracts of calcium-silicate cements sustained OFMSC survival, maintained steady state levels of vascular cell adhesion molecule-1, alkaline phosphatase and bone sialoprotein while upregulating their respective gene transcripts. Adipogenic and in vivo bone regenerative capacities of OFMSCs were also unaffected by calcium-silicate extracts. Conclusions Ion-releasing calcium-silicate cements support a biomimetic microenvironment conducive to survival and differentiation of OFMSCs. Combination of OFMSCs and calcium-silicate cement can potentially promote tissue regeneration in periapical bone defects.

Gandolfi, Maria Giovanna; Shah, Sara N.; Feng, Ruoxue; Prati, Carlo; Akintoye, Sunday O.

2011-01-01

312

Development of a 3D polymer reinforced calcium phosphate cement scaffold for cranial bone tissue engineering  

NASA Astrophysics Data System (ADS)

The repair of critical-sized cranial bone defects represents an important clinical challenge. The limitations of autografts and alloplastic materials make a bone tissue engineering strategy desirable, but success depends on the development of an appropriate scaffold. Key scaffold properties include biocompatibility, osteoconductivity, sufficient strength to maintain its structure, and resorbability. Furthermore, amenability to rapid prototyping fabrication methods is desirable, as these approaches offer precise control over scaffold architecture and have the potential for customization. While calcium phosphate cements meet many of these criteria due to their composition and their injectability, which can be leveraged for scaffold fabrication via indirect casting, their mechanical properties are a major limitation. Thus, the overall goal of this work was to develop a 3D polymer reinforced calcium phosphate cement scaffold for use in cranial bone tissue engineering. Dicalcium phosphate dihydrate (DCPD) setting cements are of particular interest because of their excellent resorbability. We demonstrated for the first time that DCPD cement can be prepared from monocalcium phosphate monohydrate (MCPM)/hydroxyapatite (HA) mixtures. However, subsequent characterization revealed that MCPM/HA cements rapidly convert to HA during degradation, which is undesirable and led us to choose a more conventional formulation for scaffold fabrication. In addition, we developed a novel method for calcium phosphate cement reinforcement that is based on infiltrating a pre-set cement structure with a polymer, and then crosslinking the polymer in situ. Unlike prior methods of cement reinforcement, this method can be applied to the reinforcement of 3D scaffolds fabricated by indirect casting. Using our novel method, composites of poly(propylene fumarate) (PPF) reinforced DCPD were prepared and demonstrated as excellent candidate scaffold materials, as they had increased strength and ductility and were biocompatible in vitro. Furthermore, 3D PPF reinforced DCPD scaffolds had strengths comparable to trabecular bone. Based on these results, 3D PPF reinforced DCPD scaffolds were evaluated in vivo using a rabbit calvarial defect model. Although bone formation was not enhanced by the addition of mesenchymal stem cells, significant bone ingrowth from the surrounding tissue was observed. The results of this work provide a foundation for future research on 3D polymer reinforced calcium phosphate cement scaffolds.

Alge, Daniel L.

313

The effect of premixed schedule on the crystal formation of calcium phosphate cement-chitosan composite with added tetracycline.  

PubMed

In this study, calcium phosphate cements (CPC) were prepared by mixing cement powders of tetracalcium phosphate (TTCP) with a cement liquid of phosphate acid saline solution. Tetracycline (TTC)-CPC, chitosan-CPC and chitosan-TTC-CPC were investigated with different premixed schedule. It was demonstrate that both TTC and chitosan worked on the phase transition and crystal characteristics. TTCP mixed with phosphate acid saline solution had similar features of Fourier transform-infrared spectrometry (FT-IR) no matter it was mixed with chitosan or TTC or both. TTC premixed with cement liquid or powder had significant different features of FT-IR and 876 cm(-1) seemed to be a special peak for TTC when TTC was premixed with cement liquid. This was also supported by XRD analysis, which showed that TTC premixed with cement liquid improved phase transition of TTCP to OCP. Chitosan, as organic additive, regulates the regular crystal formation and inhibits the phase transition of TTCP to OCP, except when it is mingled with cement liquid premixed with TTC in field scanning electron microscope. It was concluded that the premixed schedule influences the crystal formation and phase transition, which may be associated with its biocompatibility and bioactivities in vivo. PMID:18704318

Mao, Jing; Liu, Yan; Zhou, Bin; Yao, Liyun

2008-08-15

314

CAD\\/CAM Zirconia vs. slip-cast glass-infiltrated Alumina\\/Zirconia all-ceramic crowns: 2-year results of a randomized controlled clinical trial  

Microsoft Academic Search

Zirconia crowns were fabricated and cemented with a glass ionomer cement in 20 patients. At baseline, 6-month, 1-year, and 2-year recall appointments, Californian Dental Association (CDA) quality evaluation system was used to evaluate the prosthetic replacements, and plaque and gingival index scores were used to explore the periodontal outcome of the treatments. No clinical sign of marginal discoloration, persistent pain

Murat Cavit Çehreli; Ali Murat Kökat; Kivanç Akça

2009-01-01

315

Doped biocompatible layers prepared by laser  

NASA Astrophysics Data System (ADS)

The contribution deals with KrF laser synthesis and study of doped biocompatible materials with focus on diamond-like carbon (DLC) and hydroxyapatite (HA). Overview of materials used for dopation is given. Experimental results of study of HA layers doped with silver are presented. Films properties were characterized using profilometer, SEM, WDX, XRD and optical transmission. Content of silver in layers moved from 0.06 to 13.7 at %. The antibacterial properties of HA, silver and doped HA layers were studied in vivo using Escherichia coli cells.

Jelínek, M.; Weiserová, M.; Kocourek, T.; Jurek, K.; Strnad, J.

2010-03-01

316

Premixed calcium phosphate cements: Synthesis, physical properties, and cell cytotoxicity  

PubMed Central

Objectives Calcium phosphate cement (CPC) is a promising material for dental, periodontal, and craniofacial repairs. However, its use requires on-site powder–liquid mixing that increases the surgical placement time and raises concerns of insufficient and inhomogeneous mixing. The objective of this study was to determine a formulation of premixed CPC (PCPC) with rapid setting, high strength, and good in vitro cell viability. Methods PCPCs were formulated from CPC powder + non-aqueous liquid + gelling agent + hardening accelerator. Five PCPCs were thus developed: PCPC-Tartaric, PCPC-Malonic, PCPC-Citric, PCPC-Glycolic, and PCPC-Malic. Formulations and controls were compared for setting time, diametral tensile strength, and osteoblast cell compatibility. Results Setting time (mean ± S.D.; n = 4) for PCPC-Tartaric was 8.2 ± 0.8 min, significantly less than the 61.7 ± 1.5 min for the Premixed Control developed previously (p < 0.001). On 7th day immersion, the diametral tensile strength of PCPC-Tartaric reached 6.5 ± 0.8 MPa, higher than 4.5 ± 0.8 MPa of Premixed Control (p = 0.036). Osteoblast cells displayed a polygonal morphology and attached to the nano-hydroxyapatite crystals in the PCPCs. All cements had similar live cell density values (p = 0.126), indicating that the new PCPCs were as cell compatible as a non-premixed CPC control known to be biocompatible. Each of the new PCPCs had a cell viability that was not significantly different (p > 0.1) from that of the non-premixed CPC control. Significance PCPCs will eliminate the powder–liquid mixing during surgery and may also improve the cement performance. The new PCPCs supported cell attachment and yielded a high cell density and viability. Their mechanical strengths approached the reported strengths of sintered porous hydroxyapatite implants and cancellous bone. These nano-crystalline hydroxyapatite cements may be useful in dental, periodontal, and craniofacial repairs.

Xu, Hockin H.K.; Carey, Lisa E.; Simon, Carl G.; Takagi, Shozo; Chow, Laurence C.

2009-01-01

317

Biocompatible, hyaluronic acid modified silicone elastomers.  

PubMed

Although silicones possess many useful properties as biomaterials, their hydrophobicity can be problematic. To a degree, this issue can be addressed by surface modification with hydrophilic polymers such as poly(ethylene glycol), but the resulting structures are usually not conducive to cell growth. In the present work, we describe the synthesis and characterization of covalently linked hyaluronic acid (HA) (35 kDa) to poly(dimethylsiloxane) (PDMS) elastomer surfaces. HA is of interest because of its known biological properties; its presence on a surface was expected to improve the biocompatibility of silicone materials for a wide range of bioapplications. HA was introduced with a coupling agent in two steps from high-density, tosyl-modified, poly(ethylene glycol) tethered silicone surfaces. All materials synthesized were characterized by water contact angle, ATR-FTIR, XPS and (13)C solid state NMR spectroscopy. Biological interactions with these modified silicone surfaces were assessed by examining interactions with fibrinogen as a model protein as well as determining the in vitro response of fibroblast (3T3) and human corneal epithelial cells relative to unmodified poly(dimethylsiloxane) controls. The results suggest that HA modification significantly enhances cell interactions while decreasing protein adsorption and may therefore be effective for improving biocompatibility of PDMS and other materials. PMID:20138660

Alauzun, Johan G; Young, Stuart; D'Souza, Renita; Liu, Lina; Brook, Michael A; Sheardown, Heather D

2010-02-06

318

Cytotoxicity of calcium enriched mixture cement compared with mineral trioxide aggregate and intermediate restorative material.  

PubMed

Calcium enriched mixture (CEM) cement has been recently invented by the last author. It is composed of calcium oxide, calcium phosphate, calcium silicate and calcium sulphate; however, it has a different chemical composition to mineral trioxide aggregate (MTA). The purpose of this ex vivo study was to investigate the cytotoxicity of CEM cement, and compare it with intermediate restorative material (IRM) and MTA. The materials were tested in fresh and set states on L929 fibroblasts to assess their cytotoxicity. The cell viability responses were evaluated with methyl-tetrazolium bromide assay and Elisa reader at 1, 24 and 168 h (7 days). The tested materials were eluted with L929 culture medium according to international standard organisation 109935 standard. Distilled water and culture medium served as positive and negative controls, respectively. Differences in cytotoxicity were evaluated by one-way anova and t-tests. The cytotoxicity of the materials was statistically different at the three time intervals (P < 0.01). The lowest cytotoxic values recorded were expressed by MTA subgroups followed by CEM cement; IRM subgroups were the most cytotoxic root-end/dental material (P < 0.001). CEM cement and MTA are reasonable alternatives to IRM because of lower cytotoxicity. CEM cement also has good biocompatibility as well as lower estimated cost to MTA and seems to be a promising dental material. PMID:22827819

Mozayeni, Mohammad A; Milani, Amin S; Marvasti, Laleh A; Asgary, Saeed

2010-10-24

319

Polymeric additives to enhance the functional properties of calcium phosphate cements.  

PubMed

The vast majority of materials used in bone tissue engineering and regenerative medicine are based on calcium phosphates due to their similarity with the mineral phase of natural bone. Among them, calcium phosphate cements, which are composed of a powder and a liquid that are mixed to obtain a moldable paste, are widely used. These calcium phosphate cement pastes can be injected using minimally invasive surgery and adapt to the shape of the defect, resulting in an entangled network of calcium phosphate crystals. Adding an organic phase to the calcium phosphate cement formulation is a very powerful strategy to enhance some of the properties of these materials. Adding some water-soluble biocompatible polymers in the calcium phosphate cement liquid or powder phase improves physicochemical and mechanical properties, such as injectability, cohesion, and toughness. Moreover, adding specific polymers can enhance the biological response and the resorption rate of the material. The goal of this study is to overview the most relevant advances in this field, focusing on the different types of polymers that have been used to enhance specific calcium phosphate cement properties. PMID:22511991

Perez, Roman A; Kim, Hae-Won; Ginebra, Maria-Pau

2012-03-20

320

Calculator programs replace cementing tables  

Microsoft Academic Search

Two programs written for use on the two most popular programmable calculators solve routine volume and fill problems using data available on the drill floor. And while those familiar books of cementing tables should be kept for special jobs, the programs given here provide quick solutions to everyday cementing problems. Programs are presented for the solution of annular volume and

Landry

1987-01-01

321

A cement based syntactic foam  

Microsoft Academic Search

In this study, a cement based syntactic foam core was proposed and experimentally investigated for composite sandwich structures. This was a multi-phase composite material with microballoon dispersed in a rubber latex toughened cement paste matrix. A trace amount of microfiber was also incorporated to increase the number of mechanisms for energy absorption and a small amount of nanoclay was added

Guoqiang Li; Venkata D. Muthyala

2008-01-01

322

Cell alignment using patterned biocompatible gold nanoparticle templates.  

PubMed

Biocompatible structures are produced for cellular patterning. The biocompatible surfaces are generated to provide protein nonfouling patterns, offering direct communication to the cells for controlling cell adhesion and proliferation. These biofunctional surfaces provide a platform for aligning the cells in the direction of patterns, indicating potential application in the field of tissue engineering. PMID:22354857

Subramani, Chandramouleeswaran; Saha, Krishnendu; Creran, Brian; Bajaj, Avinash; Moyano, Daniel F; Wang, Hao; Rotello, Vincent M

2012-02-22

323

Fabrication and biocompatibility of polypyrrole implants suitable for neural prosthetics  

Microsoft Academic Search

Finding a conductive substrate that promotes neural interactions is an essential step for advancing neural interfaces. The biocompatibility and conductive properties of polypyrrole (PPy) make it an attractive substrate for neural scaffolds, electrodes, and devices. Stand-alone polymer implants also provide the additional advantages of flexibility and biodegradability. To examine PPy biocompatibility, dissociated primary cerebral cortical cells were cultured on PPy

Paul M. George; Alvin W. Lyckman; David A. LaVan; Anita Hegde; Yuika Leung; Rupali Avasare; Chris Testa; Phillip M. Alexander; Robert Langer; Mriganka Sur

2005-01-01

324

Biocompatibility studies of materials used for chronically implantable microelectrodes  

Microsoft Academic Search

The use of biocompatible materials is important in determining the longevity of chronically implantable microelectrodes. Protein adsorption is the initial event that takes place once an implant is in the body. These adsorbed proteins are then a significant influence on the subsequent adsorption of further proteins and cells; they thus dictate the interfacial reactions and ultimately the biocompatibility of the

Jamuna Selvakumaran; Michael P. Hughes; David J. Ewins; Peter R. Richards

2000-01-01

325

Dual setting ?-tricalcium phosphate cements.  

PubMed

An extension of the application of calcium phosphate cements (CPC) to load-bearing defects, e.g. in vertebroplasty, would require less brittle cements with an increased fracture toughness. Here we report the modification of CPC made of alpha-tricalcium phosphate (?-TCP) with 2-hydroxyethylmethacrylate (HEMA), which is polymerised during setting to obtain a mechanically stable polymer-ceramic composite with interpenetrating organic and inorganic networks. The cement liquid was modified by the addition of 30-70 % HEMA and ammoniumpersulfate/tetramethylethylendiamine as initiator. Modification of ?-TCP cement paste with HEMA decreased the setting time from 14 min to 3-8 min depending on the initiator concentration. The 4-point bending strength was increased from 9 MPa to more than 14 MPa when using 50 % HEMA, while the bending modulus decreased from 18 GPa to approx. 4 GPa. The addition of ?50 % HEMA reduced the brittle fracture behaviour of the cements and resulted in an increase of the work of fracture by more than an order of magnitude. X-ray diffraction analyses revealed that the degree of transformation of ?-TCP to calcium deficient hydroxyapatite was lower for polymer modified cements (82 % for polymer free cement and 55 % for 70 % HEMA) after 24 h setting, while the polymerisation of HEMA in the cement liquid was quantitative according to FT-IR spectroscopy. This work demonstrated the feasibility of producing fracture resistant dual-setting calcium phosphate cements by adding water soluble polymerisable monomers to the liquid cement phase, which may be suitable for an application in load-bearing bone defects. PMID:23239262

Christel, T; Kuhlmann, M; Vorndran, E; Groll, J; Gbureck, U

2012-12-13

326

The effect of cement composition and pH of environment on sulfate resistance of Portland cements and blended cements  

Microsoft Academic Search

This paper presents an investigation into the sulfate resistance of Portland cements and blended cements. Four Portland cements of different characteristics and blended cements containing fly ash, ground granulated blast furnace slag and silica fume were used in this work. The performances of binders were evaluated in sulfate solutions maintained at different pH levels ranging from 3 to 12 using

H. T. Cao; L. Bucea; A. Ray; S. Yozghatlian

1997-01-01

327

Quantitative analysis of the resorption and osteoconduction of a macroporous calcium phosphate bone cement for the repair of a critical size defect in the femoral condyle.  

PubMed

Clinical orthopaedic use of calcium phosphate cement has been limited due to its slow resorption rate, but a new macroporous alpha-tricalcium phosphate (alpha-TCP) bone cement has been designed to accelerate resorption and to increase bone ingrowth. To assess its clinical potential, the in vivo behaviour of alpha-TCP was evaluated in a critical-size defect drilled in the femoral condyles of 36 adult female New Zealand rabbits. Macroporous or standard cement was injected immediately after preparation of the defect. The foaming agent was albumen, which gave up to 75% porosity. The rabbits were divided into three groups and the lesions examined histopathologically at 1, 4 and 12 weeks. No inflammatory reaction was detected at any time period following implantation with either macroporous or standard cement. At 12 weeks, the area of the implanted macroporous cement was approximately 35% of the initial lesion size. Bone growth and revascularisation was observed inside the central pores of the macroporous cement, not only at the margins, as was found with standard calcium phosphate cement. The results indicated that both cements were osteoconductive, biocompatible and biodegradable but their different physicochemical and biological properties had a marked influence on their post-implant behaviour. PMID:17980634

Miño-Fariña, Natalia; Muñoz-Guzón, Fernando; López-Peña, Mónica; Ginebra, Maria-Pau; Del Valle-Fresno, Sergio; Ayala, Dolors; González-Cantalapiedra, Antonio

2007-11-05

328

Si-based Nanoparticles: a biocompatibility study  

NASA Astrophysics Data System (ADS)

Exposure to silicon nanoparticles (Si-NPs) may occur in professional working conditions or for people undergoing a diagnostic screening test. Despite the fact that silicon is known as a non-toxic material, in the first case the risk is mostly related to the inhalation of nanoparticles, thus the most likely route of entry is across the lung alveolar epithelium. In the case of diagnostic imaging, nanoparticles are usually injected intravenously and Si-NPs could impact on the endothelial wall. In our study we investigated the interaction between selected Si-based NPs and an epithelial lung cell line. Our data showed that, despite the overall silicon biocompatibility, however accurate studies of the potential toxicity induced by the nanostructure and engineered surface characteristics need to be accurately investigated before Si nanoparticles can be safely used for in vivo applications as bio-imaging, cell staining and drug delivery.

Rivolta, I.; Lettiero, B.; Panariti, A.; D'Amato, R.; Maurice, V.; Falconieri, M.; Herlein, N.; Borsella, E.; Miserocchi, G.

2010-10-01

329

Titanium nanostructural surface processing for improved biocompatibility  

SciTech Connect

X-ray photoelectron spectroscopy, grazing incident x-ray diffraction, transmission electron microscopy, and scanning electron microscopy were conducted to evaluate the effect of titanium hydride on the formation of nanoporous TiO{sub 2} on Ti during anodization. Nano-titanium-hydride was formed cathodically before anodizing and served as a sacrificial nanoprecipitate during anodization. Surface oxidation occurred and a multinanoporous structure formed after cathodic pretreatments followed by anodization treatment. The sacrificial nanoprecipitate is directly dissolved and the Ti transformed to nanoporous TiO{sub 2} by anodization. The formation of sacrificial nanoprecipitates by cathodic pretreatment and of the multinanostructure by anodization is believed to improve biocompatibility, thereby promoting osseointegration.

Cheng, H.-C.; Lee, S.-Y.; Chen, C.-C.; Shyng, Y.-C.; Ou, K.-L. [School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China)and Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China) and Department of Emergency Medicine, Mackay Memorial Hospital, Taipei 110, Taiwan (China); Division of Oral and Maxillofacial Surgery, Kaohsiung Military General Hospital, Kaohsiung 807, Taiwan (China); Graduate Institute of Oral Sciences, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China)

2006-10-23

330

Biocompatibility of microparticles into soft tissue fillers.  

PubMed

The increasing need for long-lasting injectable soft tissue fillers for the treatment of wrinkles and folds requires a critical discussion of the biocompatibility on a scientific background. Since biological fillers made of collagen and hyaluronic acid will be resorbed over time, copolymer biomaterials with microparticles have been developed in recent years. The microparticles followed special and essential demands because of the interaction with the tissue. In search of an ideal soft tissue filler substance, a variety of biomaterials with microparticles suspended have been created for injecting into dermal defects, into the urethra of patients with urinary incontinence, and in patients with vocal cord insufficiency. The particles differ in chemical composition, surface structure, surface charge, and particle size and evoke different host reactions, accordingly. PMID:15745227

Laeschke, Klaus

2004-12-01

331

Prospective randomized control trial comparing Biostop, a bioabsorbable cement restrictor with the standard Hardinge cement plug  

Microsoft Academic Search

This study is a randomized control trial comparing the effectiveness of Biostop, an absorbable cement restrictor with Hardinge, a nonabsorbable cement restrictor in 136 consecutive patients who had a Charnley total hip replacement inserted. Type of cement restrictor, the surgical approach, the surgeon, the viscosity of the cement, the cementing technique, and the femoral canal diameter were statistically compared to

A. Mofidi; H. Kapoor; R. Kumar; J. Rice; H. Smyth; G. C. Fenelon; J. McElwain; D. Borton

2004-01-01

332

Biostability and biocompatibility of modified polyurethane elastomers  

NASA Astrophysics Data System (ADS)

Several strategies have been employed to increase the biostability of medical grade polyurethanes while maintaining the desirable properties of current poly(ether urethanes). It was hypothesized that polyurethane surface chemistry controls biodegradation/biostability that can lead to ultimate failure/success of these materials in clinical applications. Chemical modification or replacement of the susceptible soft segment was evaluated as a design strategy to increase the biostability of medical grade polyurethanes. The effect of soft segment chemistry on the phase morphology, mechanical properties and in vivo response of commercial polyurethanes were compared. Poly(ether urethane) (PEU), silicone-modified poly(ether urethane) (PEU-S), poly(carbonate urethane) (PCU) and silicone-modified poly(carbonate urethane) (PCU-S) elastomers were investigated. AFM phase imaging indicated that the overall two-phase morphology of poly(ether urethanes), necessary for its thermoplastic elastomeric properties, was not disrupted by changing the soft segment chemistry. All of the polyurethanes exhibited thermoplastic elastomeric behavior similar to that of the poly(ether urethane). Following material characterization, the biocompatibility of the polyurethane elastomers was evaluated using a subcutaneous cage implant protocol. All of the polyurethanes tested retained the excellent biocompatibility typical of poly(ether urethane) elastomers. Overall, the candidate polyurethanes were concluded to be suitable replacements of current poly(ether urethane) elastomers in medical applications. The results from the cage implant study and cell culture experiments indicated that monocytes adhere, differentiate and fuse to form foreign body giant cells (FBGCs) on all of the polyurethane specimens. It is now generally accepted that the reactive oxygen species released by these adherent macrophages and FBGCs initiate PEU biodegradation. ATR-FTIR analysis of explanted samples provided evidence of chain scission and crosslinking in all of the polyurethane specimens. Therefore, it was concluded that the chosen soft segment modifications were insufficient to fully inhibit biodegradation. (Abstract shortened by UMI.)

Christenson, Elizabeth Marie

333

Holocene cemented beach deposits in Belize  

Microsoft Academic Search

Two types of cemented beach deposits occur on reef islands off the coast of Belize. These are (1) intertidal beachrock that is dominantly cemented by marine aragonite and high-magnesium-calcite cements, and (2) supratidal cayrock that is cemented mainly by vadose low-magnesium-calcite cements. Besides differences in position relative to present sea level and resulting early diagenesic features, beachrock and cayrock can

Eberhard Gischler; Anthony J. Lomando

1997-01-01

334

Molecular mechanisms of crystallization impacting calcium phosphate cements  

PubMed Central

The biomineral calcium hydrogen phosphate dihydrate (CaHPO4·2H2O), known as brushite, is a malleable material that both grows and dissolves faster than most other calcium minerals, including other calcium phosphate phases, calcium carbonates and calcium oxalates. Within the body, this ready formation and dissolution can play a role in certain diseases, such as kidney stone and plaque formation. However, these same properties, along with brushite’s excellent biocompatibility, can be used to great benefit in making resorbable biomedical cements. To optimize cements, additives are commonly used to control crystallization kinetics and phase transformation. This paper describes the use of in situ scanning probe microscopy to investigate the role of several solution parameters and additives in brushite atomic step motion. Surprisingly, this work demonstrates that the activation barrier for phosphate (rather than calcium) incorporation limits growth kinetics and that additives such as magnesium, citrate and bisphosphonates each influence step motion in distinctly different ways. Our findings provide details of how, and where, molecules inhibit or accelerate kinetics. These insights have the potential to aid in designing molecules to target specific steps and to guide synergistic combinations of additives.

Giocondi, Jennifer L.; El-Dasher, Bassem S.; Nancollas, George H.; Orme, Christine A.

2010-01-01

335

Thrombocytopenia in the Setting of Hemodialysis Using Biocompatible Membranes  

PubMed Central

Thrombocytopenia is a known potential side effect of hemodialysis, however, it is rarely seen in patients who undergo hemodialysis using biocompatible membranes. This case demonstrates hemodialysis-associated thrombocytopenia with use of biocompatible dialysis membranes that expose blood directly to polysulfone. The thrombocytopenia resolved in this patient when the dialysis membrane was changed to a biocompatible model with a polyethylene glycol barrier layer preventing direct interaction between patient blood and polysulfone. The calculated Naranjo ADR score of 9 indicates a highly probable adverse reaction.

Muir, Kathryn B.; Packer, Clifford D.

2012-01-01

336

Overview of Stabilizing Ligands for Biocompatible Quantum Dot Nanocrystals  

PubMed Central

Luminescent colloidal quantum dots (QDs) possess numerous advantages as fluorophores in biological applications. However, a principal challenge is how to retain the desirable optical properties of quantum dots in aqueous media while maintaining biocompatibility. Because QD photophysical properties are directly related to surface states, it is critical to control the surface chemistry that renders QDs biocompatible while maintaining electronic passivation. For more than a decade, investigators have used diverse strategies for altering the QD surface. This review summarizes the most successful approaches for preparing biocompatible QDs using various chemical ligands.

Zhang, Yanjie; Clapp, Aaron

2011-01-01

337

Short-Term Analysis of Human Dental Pulps After Direct Capping with Portland Cement  

PubMed Central

This study evaluated the short-term response of human pulp tissue when directly capped with Portland cement. In this series of cases, twenty human third molars that were scheduled for extraction were used. After cavity preparation, pulp exposure was achieved and Portland cement pulp capping was performed. Teeth were extracted after 1, 7, 14 and 21 days following treatment and prepared for histological examination and bacterial detection. Each group had 5 teeth. The results were descriptively analysed. Dentin bridge formation was seen in two teeth with some distance from the material interface (14 and 21 days). Soft inflammatory responses were observed in most of the cases. Bacteria were not disclosed in any specimen. PC exhibited some features of biocompatibility and capability of inducing mineral pulp response in short-term evaluation. The results suggested that PC has a potential to be used as a less expensive pulp capping material in comparison to other pulp capping materials.

Barbosa, Antonio Vinicius Holanda; Sampaio, Gerhilde Callou; Gomes, Fabio Almeida; de Oliveira, Daniel Pinto; de Albuquerque, Diana Santana; Sobral, Ana Paula Veras

2009-01-01

338

Carbon nanotube biocompatibility with cardiac muscle cells  

NASA Astrophysics Data System (ADS)

Purified carbon nanotubes are new carbon allotropes, sharing similarities with graphite, that have recently been proposed for their potential use with biological systems as probes for in vitro research and for diagnostic and clinical purposes. However the biocompatibility of carbon nanotubes with cells represents an important problem that, so far, remains largely uninvestigated. The objective of this in vitro study is to explore the cytocompatibility properties of purified carbon nanofibres with cardiomyocytes. Cardiac muscle cells from a rat heart cell line H9c2 (2-1) have been used. Highly purified single-walled nanotubes (SWNTs) were suspended at the concentration of 0.2 mg ml-1 by ultrasound in complete Dulbecco's modified Eagle's medium, and administered to cells to evaluate cell proliferation and shape changes by light microscopy, cell viability by trypan blue exclusion, and apoptosis, determined flow cytometrically by annexin/PI staining. Microscopic observation evidenced that carbon nanotubes bind to the cell membrane, causing a slight modification in cell shape and in cell count only after three days of treatment. Cell viability was not affected by carbon nanotubes in the first three days of culture, while after this time, cell death was slightly higher in nanotube-treated cells (p = ns). Accordingly, nanotube treatment induced little and non-significant change in the apoptotic cell number at day 1 and 3. The effect of nanotubes bound to cells was tested by reseeding treated cardiomyocytes. Cells from a trypsinized nanotube-treated sample showed a limited ability to proliferate, and a definite difference in shape, with a high degree of cell death: compared to reseeded untreated ones, in SWNT-treated samples the annexin-positive/PI-negative cells increased from 2.9% to 9.3% in SWNT (p<0.05, where p<0.05 defines a statistically significant difference with a probability above 95%), and the annexin-positive/PI-positive cells increased from 5.2% to 18.7% (p<0.05). However, overtime cells from a trypsinized nanotube-treated sample continued to grow, and partially recovered the original shape. In conclusion our results demonstrate that highly purified carbon nanotubes possess no evident short-term toxicity and can be considered biocompatible with cardiomyocytes in culture, while the long-term negative effects, that are evidenced after reseeding, are probably due to physical rather than chemical interactions.

Garibaldi, Silvano; Brunelli, Claudio; Bavastrello, Valter; Ghigliotti, Giorgio; Nicolini, Claudio

2006-01-01

339

ADVANCED CEMENTS FOR GEOTHERMAL WELLS  

Microsoft Academic Search

Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiOâ-HâO system) and calcium aluminum silicate hydrates (CaO-AlâOâ-SiOâ-HâO system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly

Toshifumi Sugama

2007-01-01

340

Cement pulmonary embolism after vertebroplasty.  

PubMed

In recent years, the use of vertebral cementing techniques for vertebroplasty and kyphoplasty has spread for the treatment of pain associated with osteoporotic vertebral compression fractures. This is also associated with the increased incidence of complications related with these procedures, the most frequent being originated by leakage of cementation material. Cement can escape into the vertebral venous system and reach the pulmonary circulation through the azygous system and cava vein, producing a cement embolism. This is a frequent complication, occurring in up to 26% of patients undergoing vertebroplasty but, since most patients have no clinical or hemodynamical repercussion, this event usually goes unnoticed. However, some serious, and even fatal cases, have been reported. We report the case of a 74-year-old male patient who underwent vertebroplasty for persistent pain associated with osteoporotic L3 vertebral fracture and who developed a cement leak into the cava vein and right pulmonary artery during the procedure. Although he developed a pulmonary cement embolism, the patient remained asymptomatic and did not present complications during follow-up. PMID:23481509

Sifuentes Giraldo, Walter Alberto; Lamúa Riazuelo, José Ramón; Gallego Rivera, José Ignacio; Vázquez Díaz, Mónica

2013-03-06

341

Method for Making Biocompatible Polymer Articles Using Atomic Oxygen.  

National Technical Information Service (NTIS)

A method for making a biocompatible polymer article using a uniform atomic oxygen treatment is disclosed. The substrate may be subsequently optionally grafted with a compatibilizing compound. Compatibilizing compounds may include proteins, phosphorylcholi...

S. Koontz G. Spaulding

1992-01-01

342

Manufacture and properties of fluoride cement  

NASA Astrophysics Data System (ADS)

This research work aimed at characterising composition, hydration and physical properties of fluoride cement, by studying samples of the cement obtained from Malawi, and comparing them to ordinary Portland cement. By confirming the suitable characteristics of fluoride cement through this work, the results of the research work provide a good basis for the wider adoption of fluoride cement as an alternative to ordinary Portland cement, especially in developing economies. Numerous accounts have been cited regarding the production and use of fluoride cement. Since there have not been conclusive agreement as to its properties, this study was limited to the theories of successful incorporation of fluoride compounds in the manufacture of fluoride cement. Hence, the properties and characteristics reported in this study relate to the cement currently manufactured in Malawi, and, on a comparative basis only, to that manufactured in other parts of the world. Samples of the fluoride cement used in the study were obtained by synthetic manufacture of the cement using common raw materials for the manufacture of fluoride cement that is limestone, silica sand, and fluorspar. These samples were subjected to several comparative tests used to characterise cements including examination under x-ray diffractometer, scanning electron microscopy and tests for setting time and compressive strength. Under similar laboratory conditions, it was possible to prove that fluoride cement hardens more rapidly than ordinary Portland cement. Also observed during the experimental work is that fluoride cement develops higher compressive strengths than ordinary Portland cement. The hardening and setting times are significantly different between the two cements. Also the nature of the hydration products, that is the microstructural development is significantly different in the two cements. The differences brought about between the two cements are because of the presence of fluorine during the clinkering process. It was observed in the laboratory simulated production of fluoride cement, that the clinkering temperature is much lower (around 1 170 °C) compared to that for the production of ordinary Portland cement. The other observed differences were attributed to the different mineralogical composition as a result of fluoride incorporation into the cement. While fluorine content is very minimal in fluoride cement, not more than 2 %, the resulting cementitious products are altered significantly as was observed from the study. Part of the experimental results has been used as reference material in the preparation of a draft Malawi Standard on fluoride cement. This draft standard will be submitted to the Malawi Bureau of Standards for further processing before it can be officially endorsed as a Malawi Standard.

Malata-Chirwa, Charles David

343

Biocompatible peritoneal dialysis solutions: many questions but few answers.  

PubMed

The clinical value of biocompatible peritoneal dialysis solutions is uncertain because of inconsistent findings in randomized controlled trials. A systematic review by Cho et al. examining 20 such trials suggests a beneficial effect on residual renal function. However, the finding is not robust and may relate to decreased ultrafiltration causing hypervolemia. Future prescribing of these biocompatible solutions will probably continue to be driven by opinion, marketing, and cost considerations rather than by evidence-based medicine. PMID:24172730

Blake, Peter G; Jain, Arsh K; Yohanna, Sechelle

2013-11-01

344

Tribological study of lubricious DLC biocompatible coatings.  

PubMed

DLC (diamond-like carbon) coatings have remarkable tribological properties due mainly to their good frictional behavior. These coatings can be applied in many industrial and biomedical applications, where sliding can generate wear and frictional forces on the components, such as orthopaedic metal implants. This work reports on the development and tribological characterization of functionally gradient titanium alloyed DLC coatings. A PVD-magnetron sputtering technique has been used as the deposition method. The aim of this work was to study the tribological performance of the DLC coating when metal to metal contact (cobalt chromium or titanium alloys) takes place under dry and lubricated test conditions. Prior work by the authors demonstrates that the DLC coating reduced considerably the wear of the ultra-high-molecular-weight polyethylene (UHMWPE). The DLC coating during mechanical testing exhibited a high elastic recovery (65%) compared to the values obtained from Co-Cr-Mo (15%) and Ti-6Al-4V (23%). The coating exhibited an excellent tribo-performance against the Ti-6Al-4V and Co-Cr-Mo alloys, especially under dry conditions presenting a friction value of 0.12 and almost negligible wear. This coating has passed biocompatibility tests for implant devices on tissue/bone contact according to international standards (ISO 10993). PMID:15348654

Brizuela, M; Garcia-Luis, A; Viviente, J L; Braceras, I; Oñate, J I

2002-12-01

345

Polyimides as biomaterials: preliminary biocompatibility testing.  

PubMed

A number of commercially available polyimide materials were evaluated in vitro using a selected battery of levels I and II testing protocols prescribed by the National Institutes of Health Guidelines for Blood-Material Interactions. These procedures consisted of electron spectroscopy for chemical analysis and contact angle characterization surface studies, and protein adsorption, cell culture cytotoxicity, clotting time and haemolysis biocompatibility testing. The polyimide surfaces were invariant from the bulk composition with 60-80% C, 10-20% O and 2-5% N, producing advancing contact angles in the hydrophobic range (80-100 degrees). Consequently, they adsorbed significant amounts of albumin (2-3 micrograms/cm2) and fibrinogen (0.5-0.8 microgram/cm2). The polyimides also displayed an insignificant level of cytotoxicity and haemolysis, and clotting times ranged from 63 to 98% of normal. These clotting times and haemolytic index values were intermediate between the values observed for Teflon and Silastic controls. These factors, along with the strong adherence of polyimides to metal oxide substrates, indicate that polyimide materials are good candidates for further testing as encapsulants for implantable biosensors. PMID:8399958

Richardson, R R; Miller, J A; Reichert, W M

1993-07-01

346

Liposomal architecture boosts biocompatibility of nanohybrid cerasomes.  

PubMed

Biomimetic cerasome has drawn much attention as a novel drug delivery system because its atomic layer of polyorganosiloxane surface imparts higher morphological stability than conventional liposomes and its liposomal bilayer structure reduces the overall rigidity and density greatly compared to silica nanoparticles. But, the issues about the interactions between cerasomes and biological systems have not been addressed as far as we could find. Herein, we reported cellular uptake of cerasomes and their biological effects toward human umbilical vein endothelial cells (HUVECs) compared with silica nanoparticles. The results indicated that the uptake of cerasomes by HUVECs was a concentration-, time-, and energy-dependent process and occurred probably through a process of clathrin-mediated endocytosis, which resulted in rearrangement of the cell cytoskeleton. Cerasomes affected different aspects of cell function to a smaller extent than silica nanoparticles, including cell proliferation, cell cycle, cell apoptosis, endogenous ROS level and pro-inflammatory molecular expression. In a word, cerasomes are more biocompatible than silica nanoparticles due to the incorporation of the liposomal architecture into cerasomes. The preliminary data will assist in the further development of new cerasome-based delivery systems. PMID:21261456

Ma, Yan; Dai, Zhifei; Gao, Yanguang; Cao, Zhong; Zha, Zhengbao; Yue, Xiuli; Kikuchi, Jun-Ichi

2011-01-24

347

The effect of cement creep and cement fatigue damage on the micromechanics of the cement-bone interface.  

PubMed

The cement-bone interface provides fixation for the cement mantle within the bone. The cement-bone interface is affected by fatigue loading in terms of fatigue damage or microcracks and creep, both mostly in the cement. This study investigates how fatigue damage and cement creep separately affect the mechanical response of the cement-bone interface at various load levels in terms of plastic displacement and crack formation. Two FEA models were created, which were based on micro-computed tomography data of two physical cement-bone interface specimens. These models were subjected to tensile fatigue loads with four different magnitudes. Three deformation modes of the cement were considered: 'only creep', 'only damage' or 'creep and damage'. The interfacial plastic deformation, the crack reduction as a result of creep and the interfacial stresses in the bone were monitored. The results demonstrate that, although some models failed early, the majority of plastic displacement was caused by fatigue damage, rather than cement creep. However, cement creep does decrease the crack formation in the cement up to 20%. Finally, while cement creep hardly influences the stress levels in the bone, fatigue damage of the cement considerably increases the stress levels in the bone. We conclude that at low load levels the plastic displacement is mainly caused by creep. At moderate to high load levels, however, the plastic displacement is dominated by fatigue damage and is hardly affected by creep, although creep reduced the number of cracks in moderate to high load region. PMID:20692663

Waanders, Daan; Janssen, Dennis; Mann, Kenneth A; Verdonschot, Nico

2010-08-07

348

Retention of adhesive cement on the tooth surface after crown cementation  

Microsoft Academic Search

Statement of problem. Adhesive cements increase crown retention, but it is unknown if traces of cement remain undetected on the tooth surface after clinical removal of excess cement, which could exacerbate plaque retention. Purpose. This study measured the surface area, volume, mean depth, and maximum depth of a resin composite and a compomer luting cement left adherent on the tooth

Christina A. Mitchell; Maria R. Pintado; Lindsay Geary; William H. Douglas

1999-01-01

349

Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance  

Microsoft Academic Search

Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global

Irvin Allen Chen

2009-01-01

350

Kinetics of Cement Strength Development Using Different Types of Cement and Aggregates  

Microsoft Academic Search

The object of the present study is the kinetics of cement strength development using different cement and aggregate types. The model that has been developed uses the following data: (1) Composition of cement. (2) Mineral composition of clinker. (3) Cement fineness. (4) Early, standard and long-term strength data. (5) Aggregates nature. The parameters of the model are constituted by: (1)

TSAMATSOULIS DIMITRIS

351

A thermodynamic model for blended cements. II: Cement hydrate phases; thermodynamic values and modelling studies  

Microsoft Academic Search

Blended Portland cements are likely to form a substantial proportion of repository materials for the disposal of radioactive waste in the UK. A thermodynamic model has been developed therefore in order to predict the composition of the solid and aqueous phases in blended cements as a function of the bulk cement composition. The model is based on simplifying cement to

D. G. Bennett; D. Read; M. Atkins; F. P. Glasser

1992-01-01

352

Method of the Cementing of Material.  

National Technical Information Service (NTIS)

Invention relates to woodworking industry and concerns method of cementing of materials of foam plastic with duralumin, glued plywood, etc. Known methods of cementing of materials by effect of electromagnetic field of superhigh frequencies are unproductiv...

Y. G. Konovalov G. M. Shutov G. P. Khanenya E. K. Dyatko K. K. Buben

1990-01-01

353

Zeolite-Hydraulic Cement Containment Medium.  

National Technical Information Service (NTIS)

The invention generally relates to a zeolite-hydraulic cement containment medium for hazardous wastes. In particular, the invention relates to a process for preparing a zeolite-portland cement containment medium from a paste prepared by mixing zeolite in ...

P. M. Brown M. A. Maginnis C. R. Furlong M. G. Bakker G. L. Turner

1994-01-01

354

21 CFR 888.4200 - Cement dispenser.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification...intended for use in placing bone cement (§ 888.3027) into surgical sites. (b) Classification. Class I (general...

2013-04-01

355

21 CFR 872.3275 - Dental cement.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Dental cement. 872.3275 Section...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc...

2013-04-01

356

Acid corrosion resistance of different cementing materials  

Microsoft Academic Search

This study has investigated the corrosion of different hardened cementing materials, such as Portland cement (PC), alkali-activated blast furnace slag cement (ASC), lime–fly ash (LFA) blend and high alumina cement with gypsum and lime (HAC), in pH 3 nitric acid, pH 3 acetic acid, and pH 5 acetic acid solutions. Experimental results indicated that PC pastes were corroded faster than

Caijun Shi; J. A Stegemann

2000-01-01

357

Acid attack on pore-reduced cements  

Microsoft Academic Search

Because the durability of high-performance cements is as important as their strength, the performance of pore-reduced cement\\u000a (PRC) in aggressive media such as sulfuric, hydrochloric and ethanoic acids, was studied and compared with that of ordinary\\u000a Portland cement (OPC). The effects of exposure to these media on these cements were monitored by periodic visual inspection\\u000a and sample weighing. Specific interactions

D. ISRAEL; D. E Macphee; E. E Lachowski

1997-01-01

358

A comparative evaluation of the fracture strength of pulpotomized primary molars restored with various restorative materials.  

PubMed

Sixty extracted primary molars were used in the study. After pulpotomy, these were divided into four groups on the basis of restorative materials to be used. Results showed that the Ormocer had the maximum fracture strength while the posterior Glass Ionomer Cement showed the least fracture strength among the various restorative materials used in the study. PMID:17550039

Passi, Sidhi; Pandit, I K; Srivastava, Nikhil; Gugnani, Neeraj; Gupta, Monika

2007-01-01

359

Analysis of bioactive fluoride-containing calcium aluminosilicate glasses  

Microsoft Academic Search

Different decomposition methods in aqueous solutions were evaluated on their accuracy and reproducibility for the quantitative determination of the constituents of bioactive fluoride-containing glasses used in dental glass ionomer cements. The concentrations of metals can be determined rapidly and accurately by atomic absorption spectrophotometry after degrading the sample in hydrochloric or hydrofluoric acid. The latter degradation method is also suited

E. A. P De Maeyer; R. M. H Verbeeck

1998-01-01

360

Comparative evaluation of bond strengths of different core materials with various luting agents used for cast crown restorations.  

PubMed

The coronal cast restoration continues to be used commonly to restore mutilated, endodontically treated teeth. The tensile bond strength of luting cements is of critical importance as many of failures are at the core and the crown interface. An invitro study with aim to evaluate and compare bond strengths of luting cements between different core materials and cast crowns. A total of 45 extracted identical mandibular second premolars were endodontically treated and divided into 3 groups of 15 each. Specimens in first group were restored with cast post and core (Group C), and specimens in second group were restored with stainless steel parapost and composite core material (Group B) and specimens in third group were restored with stainless steel parapost and glass ionomer core build (Group G). Standardized crown preparation was done for all the specimens to receive cast crowns. Each group was further divided into 3 subgroups and were cemented using 3 different luting cements namely, resin cement, polycarboxylate cement, glass ionomer cement (Type I). The samples of each subgroup (n = 5) were subjected to tensile testing using Universal Testing Machine at a crosshead speed of 2 mm/min till the dislodgement of crown from the core surface was observed. The bond strengths were significantly different according one way ANOVA (F-150.76 and p < 0.0000). The results of the study showed that the specimens cemented with resin cement in cast core, composite core and glass ionomer core exhibited significantly higher bond strengths as compared to specimens cemented with glass ionomer and polycarboxylate cement. Composite resin core and resin cement combinations were superior to all other cement and core combinations tested. PMID:23997467

Nayakar, Ramesh P; Patil, Narendra P; Lekha, K

2012-06-04

361

New additives for minimizing cement body permeability  

Microsoft Academic Search

An experimental investigation was carried out with a new array of cement additives, replacing some of the currently used ones. In this study, the cement slurry pressure was monitored during the setting of the element. To obtain the optimum tightness of the cement, final contraction in the cycle is crucial for blockage of gas migration. Concentrations of the additives were

S. Talabani; G. Hareland; M. R. Islam

1999-01-01

362

Fatigue of cement foams in axial compression  

Microsoft Academic Search

The theoretical expression for fatigue of cement foams in axial compression is derived using dimensional argument analysis. Bending model and Basquin law for describing the fatigue of individual cell struts are employed in calculating the number of cycles to failure of cement foams. It is found that the fatigue of cement foams in axial compression depends on cyclic stress range,

Jong-Shin Huang; Zi-Herng Huang

2000-01-01

363

Global Cement Industry: Competitive and Institutional Dimensions  

Microsoft Academic Search

The cement industry is a capital intensive, energy consuming, and vital industry for sustaining infrastructure of nations. The international cement market –while constituting a small share of world industry output—has been growing at an increasing rate relative to local production in recent years. Attempts to protect the environment in developed countries –especially Europe—have caused cement production plants to shift to

Tarek Selim; Ahmed Salem

2010-01-01

364

Cementing system including real time display  

Microsoft Academic Search

A cementing system is described cooperative with a cement pumping apparatus including a connective manifold from the pumping apparatus to a well head for cementing the well in the completion thereof and wherein fluid pumped at the well head is pumped into a pipe string in the well the string having at least two sections serially joined wherein the sections

1986-01-01

365

ADVANCED CEMENTS FOR GEOTHERMAL WELLS  

SciTech Connect

Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well cements, and further their deterioration was a major impediment in expediting the development of geothermal energy resources.

SUGAMA,T.

2007-01-01

366

Biocompatibility of adhesive complex coacervates modeled after the Sandcastle glue of P. californica for craniofacial reconstruction  

PubMed Central

Craniofacial reconstruction would benefit from a degradable adhesive capable of holding bone fragments in three-dimensional alignment and gradually being replaced by new bone without loss of alignment or volume changes. Modeled after a natural adhesive secreted by the sandcastle worm, we studied the biocompatibility of adhesive complex coacervates in vitro and in vivo with two different rat calvarial models. We found that the adhesive was non-cytotoxic and supported the attachment, spreading, and migration of a commonly used osteoblastic cell line over the course of several days. In animal studies we found that the adhesive was capable of maintaining three-dimensional bone alignment in freely moving rats over a 12 week indwelling period. Histological evidence indicated that the adhesive was gradually resorbed and replaced by new bone that became lamellar across the defect without loss of alignment, changes in volume, or changes in the adjacent uninjured bone. The presence of inflammatory cells was consistent with what has been reported with other craniofacial fixation methods including metal plates, screws, tacks, calcium phosphate cements and cyanoacrylate adhesives. Collectively, the results suggest that the new bioadhesive formulation is degradable, osteoconductive and appears suitable for use in the reconstruction of craniofacial fractures.

Winslow, Brent D.; Shao, Hui; Stewart, Russell J.; Tresco, Patrick A.

2011-01-01

367

Biocompatibility correlation of polymeric materials using human osteosarcoma cells  

NASA Astrophysics Data System (ADS)

Metal implants are the preferred materials to generate articular prostheses, plates, or bone pegs in orthopedic surgery. Although titanium and titanium alloys show a relatively good biocompatibility, clinical experience revealed that coating of the metallic implant surface may increase the biocompatibility. In a search for optimum bone implant surfaces, we determined polarity and contact angle parameters of a variety of polymers and substances and correlated the findings in a biocompatibility assay using an in vitro bone cell model. We report that an optimum adherence of SAOS-2 cells to such surfaces and a good vitality for polymers are characterized by water-based contact angles of 80° and 20° for advancing and receding probes, respectively.

Geckeler, K. E.; Wacker, Roland; Aicher, Wilhelm K.

368

Method of the cementing of material  

SciTech Connect

Invention relates to woodworking industry and concerns method of cementing of materials of foam plastic with duralumin, glued plywood, etc. Known methods of cementing of materials by effect of electromagnetic field of superhigh frequencies are unproductive and do not make it possible to cement parts on the plane. Target of invention - acceleration of process of cementing of planar, including of complex configuration, parts and assemblies from wood, foam plastic, duralumin, glued plywood and other materials. For this material is cemented under the effect of directed electromagnetic field of superhigh frequency in the range 01-50 GHz, the specific power of 0.5-15 W/cm3.

Konovalov, Y.G.; Shutov, G.M.; Khanenya, G.P.; Dyatko, E.K.; Buben, K.K.

1990-10-30

369

In vitro degradation and cytocompatibility of dicalcium phosphate dihydrate cements prepared using the monocalcium phosphate monohydrate/hydroxyapatite system reveals rapid conversion to HA as a key mechanism.  

PubMed

We previously showed that dicalcium phosphate dihydrate (DCPD) cements can be prepared using monocalcium phosphate monohydrate (MCPM) and hydroxyapatite (HA). In this study, we have characterized the degradation properties and biocompatibility of these novel cements. To study the degradation properties, cements were prepared using MCPM:HA molar ratios of 4:1, 2:1, 2:3, and 2:5. Degradation was evaluated in vitro by static soaking in PBS, and changes in pH, mass, compressive strength, and composition were monitored. Conversion of DCPD to HA was noted in the 4:1 group, which initially consisted of pure DCPD. However, the 2:1 group, which initially consisted of DCPD and an intermediate amount of unreacted HA, underwent rapid conversion to HA associated with significantly greater pH drop and mass loss as well as a complete loss of mechanical integrity. On the basis of these results, we directly compared the cytocompatibility of 2:1 MCPM:HA cements to DCPD cements prepared with an equivalent percent molar excess of ?-tricalcium phosphate (?-TCP) using an in vitro cell viability assay. Viability of cells co-cultured with 2:1 MCPM:HA cements was significantly reduced after just 48 h, while viability of cells cultured with the ?-TCP-based cements was no different from control cells. In conclusion, this study demonstrates that conversion to HA plays an important role in the degradation of DCPD cements prepared with the MCPM/HA system, affecting both physical properties and cytocompatibility. These results could have important clinical implications for MCPM/HA cements. PMID:22323239

Alge, Daniel L; Goebel, W Scott; Chu, Tien-Min Gabriel

2012-02-10

370

Microtensile Bond Strength of Luting Materials to Coronal and Root Dentin  

Microsoft Academic Search

Purpose: The purpose of this study was to evaluate the microtensile bond strength (µTBS) of two dual-cured resin cements and a glass ionomer cement to coronal dentin versus root dentin. Materials and Methods: RelyX Unicem (3M ESPE, St. Paul, MN, USA) and Panavia F (Kuraray Medical Inc., Tokyo, Japan) were the resin cements used and FujiCEM (GC Corp., Tokyo, Japan)

RICARDO WALTER; PATRICIA A. MIGUEZ; PATRICIA N. R. PEREIRA

2005-01-01

371

Effects of biocompatible versus standard fluid on peritoneal dialysis outcomes.  

PubMed

The clinical benefits of using "biocompatible" neutral pH solutions containing low levels of glucose degradation products for peritoneal dialysis compared with standard solutions are uncertain. In this multicenter, open-label, parallel-group, randomized controlled trial, we randomly assigned 185 incident adult peritoneal dialysis patients with residual renal function to use either biocompatible or conventional solution for 2 years. The primary outcome measure was slope of renal function decline. Secondary outcome measures comprised time to anuria, fluid volume status, peritonitis-free survival, technique survival, patient survival, and adverse events. We did not detect a statistically significant difference in the rate of decline of renal function between the two groups as measured by the slopes of GFR: -0.22 and -0.28 ml/min per 1.73 m(2) per month (P=0.17) in the first year in the biocompatible and conventional groups, respectively, and, -0.09 and -0.10 ml/min per 1.73 m(2) per month (P=0.9) in the second year. The biocompatible group exhibited significantly longer times to anuria (P=0.009) and to the first peritonitis episode (P=0.01). This group also had fewer patients develop peritonitis (30% versus 49%) and had lower rates of peritonitis (0.30 versus 0.49 episodes per year, P=0.01). In conclusion, this trial does not support a role for biocompatible fluid in slowing the rate of GFR decline, but it does suggest that biocompatible fluid may delay the onset of anuria and reduce the incidence of peritonitis compared with conventional fluid in peritoneal dialysis. PMID:22440906

Johnson, David W; Brown, Fiona G; Clarke, Margaret; Boudville, Neil; Elias, Tony J; Foo, Marjorie W Y; Jones, Bernard; Kulkarni, Hemant; Langham, Robyn; Ranganathan, Dwarakanathan; Schollum, John; Suranyi, Michael; Tan, Seng H; Voss, David

2012-03-22

372

Thermodynamic model for blended cements.  

National Technical Information Service (NTIS)

A chemical thermodynamic model has been developed for blended cements, called CEMCHEM. Given the chemical compositions of the blend materials, CEMCHEM calculates the equilibrium phase distribution, achieved at 25(sup o)C. It is based on a portion of the C...

M. Atkins F. Glasser A. Kindness D. Bennett A. Dawes

1992-01-01

373

Process for cementing geothermal wells  

DOEpatents

A pumpable slurry of coal-filled furfuryl alcohol, furfural, and/or a low molecular weight mono- or copolymer thereof containing, preferably, a catalytic amount of a soluble acid catalyst is used to cement a casing in a geothermal well.

Eilers, Louis H. (Inola, OK)

1985-01-01

374

Damper Drives in Cement Plants  

Microsoft Academic Search

The author comprehensively treats the design factors considered in matching control systems to process control devices employed in the Portland cement industry. New developments in the areas of fluidic, SCR, and hydraulic power units employed as final element actuators are discussed and areas of application suggested.

Edward J. Pokorney

1968-01-01

375

Gelatin hydrogels: enhanced biocompatibility, drug release and cell viability  

Microsoft Academic Search

Biodegradability and enhanced biocompatibility with pH-sensitivity of hydrogels are becoming very important issues for biomaterials\\u000a applications so as to minimize the host-body reactions such as, inflammatory, antigenic, and immunogenic problems. This study\\u000a involves development of hydrogel matrices of gelatin conjugated\\/modified with highly hydrophilic, pH-sensitive and biocompatible\\u000a polymer, poly (2-ethyl-2-oxazoline) and glyoxylic acid respectively. Various compositions of gelatin conjugated\\/modified with\\u000a poly

G. V. N. Rathna

2008-01-01

376

Polymeric calcium phosphate cements: setting reaction modifiers.  

PubMed

In this study, the effects of several additives on the setting behavior and mechanical properties of polymeric calcium phosphate cements were investigated. The cements were derived from a polycarboxylic acid (PCA) and a calcium phosphate cement (CPC) powder that consisted of equimolar amounts of tetracalcium phosphate (TTCP) and dicalcium phosphate (DCPA). Retardation of the setting reaction in the PCA-CPC cements was observed by adding tribasic sodium phosphate and fluorides such as stannous fluoride, zirconium(IV) fluoride and titanium(IV) fluoride. It was found that increasing the concentration of these additives decreased the mechanical strength of the cements. However, improvements in both setting and mechanical properties for the PCA-CPC cements were observed by the combined use of 8% (w/w) stannous fluoride and 10% (w/w) tartaric acid. The mechanical properties of the PCA-CPC cement also were improved by adding calcium acetate, calcium methacrylate, zirconium(IV) sulfate and phosphonoacetic acid. PMID:8299870

Miyazaki, K; Horibe, T; Antonucci, J M; Takagi, S; Chow, L C

1993-01-01

377

Effect of two restorative materials on root dentine erosion.  

PubMed

This study sought to evaluate the microhardness of root dentine adjacent to glass-ionomer and composite resin restorations after erosive challenge. A crossover study was performed in two phases of 4 consecutive days each. One hundred twelve bovine root dentine slabs were obtained, and standardized box-shaped cavities were prepared at center of each specimen. The prepared cavities were randomly restored with glass-ionomer cement or composite resin. The slabs were randomly assigned among 14 volunteers, which wore intraoral palatal device containing four restored root dentin slabs. Starting on the second day, half of the palatal acrylic devices were immersed extraorally in a lemonade-like carbonated soft drink for 90 s, four times daily for 3 days. After 3-day wash-out, dentine slabs restored with the alternative material were placed into palatal appliance and the volunteers started the second phase of this study. After erosive challenges, microhardness measurements were performed. Regardless of the restorative material employed, eroded specimens demonstrated lower microhardness value (p < 0.0001). At eroded condition examined in this study, dentine restored with glass-ionomer cement showed higher microhardness values (p < 0.0001). It may be concluded that the glass-ionomer cement decreases the progression of root dentine erosion at restoration margin. PMID:20225213

Domiciano, Silvia Jorge; Colucci, Vivian; Serra, Mônica Campos

2010-05-01

378

Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance  

NASA Astrophysics Data System (ADS)

Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, (1) incorporation of waste materials in portland cement synthesis, and (2) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S--C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate-belite cement that contained medium C4A3 S¯ and C2S contents showed good dimensional stability, sulfate resistance, and compressive strength development and was considered the optimum phase composition for calcium sulfoaluminate-belite cement in terms of comparable performance characteristics to portland cement. Furthermore, two calcium sulfoaluminate-belite cement clinkers were successfully synthesized from natural and waste materials such as limestone, bauxite, flue gas desulfurization sludge, Class C fly ash, and fluidized bed ash proportioned to the optimum calcium sulfoaluminate-belite cement synthesized from reagent-grade chemicals. Waste materials composed 30% and 41% of the raw ingredients. The two calcium sulfoaluminate-belite cements synthesized from natural and waste materials showed good dimensional stability, sulfate resistance, and compressive strength development, comparable to commercial portland cement.

Chen, Irvin Allen

379

Effect of surface condition of dental zirconia ceramic (Denzir) on bonding.  

PubMed

Yttria partially stabilized zirconia (YPSZ) ceramics are suitable for dental and medical use because of their high fracture toughness and chemical durability. The purpose of this study was to examine the bonding behavior of a dental YPSZ ceramic, Denzir. After being subjected to various surface treatments, Denzir specimens were bonded to each other using an adhesive resin composite, glass ionomer, or zinc phosphate cement. Bonding strength was then determined by the shearing test. No significant differences (p>0.05) were observed between SiC- and Al2O3-blasted specimens. In all surface treatments, the shear bond strength significantly (p<0.05) increased in the order of adhesive resin composite cement > glass ionomer cement > zinc phosphate cement. Moreover, silanization with methacryloxy propyl trimethoxysilane slightly increased the bonding strength of the adhesive resin composite cement. PMID:17076338

Uo, Motohiro; Sjögren, Göran; Sundh, Anders; Goto, Mitsunari; Watari, Fumio; Bergman, Maud

2006-09-01

380

Properties of injectable ready-to-use calcium phosphate cement based on water-immiscible liquid.  

PubMed

Calcium phosphate cements (CPCs) are highly valuable materials for filling bone defects and bone augmentation by minimal invasive application via percutaneous injection. In the present study some key features were significantly improved by developing a novel injectable ready-to-use calcium phosphate cement based on water-immiscible carrier liquids. A combination of two surfactants was identified to facilitate the targeted discontinuous exchange of the liquid for water after contact with aqueous solutions, enabling the setting reaction to take place at distinct ratios of cement components to water. This prolonged the shelf life of the pre-mixed paste and enhanced reproducibility during application and setting reactions. The developed paste technology is applicable for different CPC formulations. Evaluations were performed for the formulation of an ?-TCP-based CPC as a representative example for the preparation of injectable pastes with a powder-to-carrier liquid ratio of up to 85:15. We demonstrate that the resulting material retains the desirable properties of conventional CPC counterparts for fast setting, mechanical strength and biocompatibility, shows improved cohesion and will most probably show a similar degree of resorbability due to identical mineral structure of the set products. PMID:23261920

Heinemann, S; Rössler, S; Lemm, M; Ruhnow, M; Nies, B

2012-12-20

381

Capacity for biocompatibility assessment in tissue culture and hydroponic systems  

Microsoft Academic Search

In vitro and hydroponic intercropping systems were compared to examine the biocompatibility responses between ‘Fiona F1’ tomato (Lycopersicon esculentum Mill.) and ‘Spunta’ potato (Solanum tuberosum). The biological response of monocultures (with four plantlets per vessel) of each species (including change in medium electrical conductivity (EC), osmotic potential (OS), and tissue mineral element content) were directly compared to intercropped cultures of

Rida A. Shibli; M. A. L. Smith

1999-01-01

382

Solution behavior of PEO : the ultimate biocompatible polymer  

Microsoft Academic Search

Poly(ethylene oxide) (PEO) is the quintessential biocompatible polymer. Due to its ability to form hydrogen bonds, it is soluble in water, and yet is uncharged and relatively inert. It is being investigated for use in a wide range of biomedical and biotechnical applications, including the prevention of protein adhesion (biofouling), controlled drug delivery, and tissue scaffolds. PEO has also been

John G. Curro; Amalie Lucile Frischknecht

2004-01-01

383

Development of biocompatible synthetic extracellular matrices for tissue engineering  

Microsoft Academic Search

Tissue engineering may provide an alternative to organ and tissue transplantation, both of which suffer from a limitation of supply. Cell transplantation using biodegradable synthetic extracellular matrices offers the possibility of creating completely natural new tissues and so replacing lost or malfunctioning organs or tissues. Synthetic extracellular matrices fabricated from biocompatible, biodegradable polymers play an important role in the formation

Byung-Soo Kim; David J Mooney

1998-01-01

384

Biocompatibility of chemoenzymatically derived dextran-acrylate hydrogels  

Microsoft Academic Search

The biocompatibility of chemoenzymatically generated dextran-acrylate hydrogels has been evaluated in vitro, using human foreskin fibroblasts, and in vivo, by sub- cutaneous and intramuscular implantation in Wistar rats for up to 40 days. In vitro tests show that hydrogel extracts only minimally reduced (10%) the mitochondrial metabolic ac- tivity of fibroblasts. Direct contact of the hydrogels with cells induced a

Lino Ferreira; Ana Rafael; Meriem Lamghari; Mario A. Barbosa; Maria H. Gil; Jonathan S. Dordick

2004-01-01

385

Dynamic In Vivo Biocompatibility of Angiogenic Peptide Amphiphile Nanofibers  

PubMed Central

Biomaterials that promote angiogenesis have great potential in regenerative medicine for rapid revascularization of damaged tissue, survival of transplanted cells, and healing of chronic wounds. Supramolecular nanofibers formed by self-assembly of a heparin-binding peptide amphiphile and heparan sulfate-like glycosaminoglycans were evaluated here using a dorsal skinfold chamber model to dynamically monitor the interaction between the nanofiber gel and the microcirculation, representing a novel application of this model. We paired this model with a conventional subcutaneous implantation model for static histological assessment of the interactions between the gel and host tissue. In the static analysis, the heparan sulfate-containing nanofiber gels were found to persist in the tissue for up to 30 days and revealed excellent biocompatibility. Strikingly, as the nanofiber gel biodegraded, we observed the formation of a de novo vascularized connective tissue. In the dynamic experiments using the dorsal skinfold chamber, the material again demonstrated good biocompatibility, with minimal dilation of the microcirculation and only a few adherent leukocytes, monitored through intravital fluorescence microscopy. The new application of the dorsal skinfold model corroborated our findings from the traditional static histology, demonstrating the potential use of this technique to dynamically evaluate the biocompatibility of materials. The observed biocompatibility and development of new vascularized tissue using both techniques demonstrates the potential of these angiogenesis-promoting materials for a host of regenerative strategies.

Ghanaati, Shahram; Webber, Matthew J.; Unger, Ronald E.; Orth, Carina; Hulvat, James F.; Kiehna, Sarah E.; Barbeek, Mike; Rasic, Angela; Stupp, Samuel I.; Kirkpatrick, C. James

2009-01-01

386

Usefulness verification of biocompatible microneedle patch for transdermal drug delivery  

Microsoft Academic Search

The key issues in the development of a microneedle patch as a tool for transdermal drug delivery are safety and delivery performance in addition to economical production. In this paper, a novel fabrication method for an inexpensive microneedle patch made of biocompatible polymer is reported, along with verifications for the fabricated microneedle patch. For microneedle patch fabrication, we combined the

Chun Yan Jin; Man Hee Han; S. S. Lee; Yo Han Choi

2009-01-01

387

Protein Adsorption and Biocompatibility of Porous Silk Fiboin Films  

Microsoft Academic Search

Silk fibroins are widely used in skin wound healing and tissue engineering scaffolds. This study sought to observe proteins adsorption and biocompatibility. Bradford protein assay revealed that the amount of adsorbed proteins was significantly less than that on PVA. The Sodium Dodecyl Sulfate Polyacrylamidege Electrophoresis (SDS-PAGE) indicated that more proteins adsorbed onto PVA than that PSFFs. Identification of adsorbed proteins

ZiLing Sun; Lun Bai; Guoping Guan; KuiHua Zhan; HongQin Dai

2009-01-01

388

Biocompatibility of visible light-cured resin systems in prosthodontics.  

PubMed

Frequently dental products are introduced that have had little or no biologic testing. Cell culture systems that traditionally have been used for the study of cellular responses have recently been used to assess biocompatibility. This article reviews various cellular toxicity assays and their application to the resin systems used in clinical prosthodontics. PMID:7510339

Lefebvre, C A; Schuster, G S

1994-02-01

389

Biocompatibility and performance in vitro of a hemostatic gelatin sponge  

Microsoft Academic Search

The biocompatibility of a hemostatic gelatin sponge (Cutanplast Standard) was evaluated in vitro. Cytotoxicity was assessed by neutral red uptake and amido black staining tests; genotoxicity was assayed using the Ames test, Sister Chromatides Exchanges (SCE) and chromosomal aberrations. The ability of the hemostatic gelatin sponge to induce platelet adhesion and release reaction was also determined. The undiluted extract of

Elisabettacenni; Gabriela Ciapetti; Susanna Stea; Alessandra Corradini; Fiorenzo Carozzi

2000-01-01

390

Fullerenol-based electroactive artificial muscles utilizing biocompatible polyetherimide.  

PubMed

Two essential functional requirements for electroactive artificial muscles, which can be used for biomedical active devices, are biocompatibility and sufficient range of motion. Fullerenol nanoparticles and their derivatives have been validated as potential candidates to be used for nanobiomaterials and biomedical applications because of their excellent proton conductivity, hydrophilicity, and biocompatibility. We developed fullerenol-based electroactive artificial muscles utilizing biocompatible polyetherimide. By using a solvent recasting method, present ionic networking membranes have been successfully synthesized with homogeneous dispersion of polyhydroxylated fullerene (PHF) nanoparticles into a sulfonated polyetherimide (SPEI) matrix. In comparison with pure SPEI membranes, the PHF-SPEI nanocomposite membranes show much higher water uptake and proton conductivity, which are both essential characteristics for high-performance ionic polymer actuators. The developed PHF-SPEI actuator shows over three times larger motion ranges and two times higher blocking forces than the pure SPEI actuator. The excellent biocompatibility of PHF and SPEI makes these actuators promising candidate materials for biomedical devices such as active stents and catheters. PMID:21332175

Rajagopalan, Mahendran; Oh, Il-Kwon

2011-02-18

391

Mechanical biocompatibilities of titanium alloys for biomedical applications  

Microsoft Academic Search

Young’s modulus as well as tensile strength, ductility, fatigue life, fretting fatigue life, wear properties, functionalities, etc., should be adjusted to levels that are suitable for structural biomaterials used in implants that replace hard tissue. These factors may be collectively referred to as mechanical biocompatibilities. In this paper, the following are described with regard to biomedical applications of titanium alloys:

Mitsuo Niinomi

2008-01-01

392

Biocompatibility study for PVP wound dressing obtained in different conditions  

Microsoft Academic Search

Hydrogels composed of PVP, PEG and agar, produced by simultaneous crosslinking and package sterilization by ionizing radiation, are used mainly as wound dressing. In this study, membranes prepared in different conditions were tested for their properties including in vitro biocompatibility. The results showed that the mechanical properties were in an acceptable range of values and that the membranes can be

O. Z Higa; S. O Rogero; L. D. B Machado; M. B Mathor; A. B Lugão

1999-01-01

393

Evaluation of Biocompatibility and Cytotoxicity Using Keratinocyte and Fibroblast Cultures  

Microsoft Academic Search

Determination of biocompatibility and cytotoxicity is part of the initial evaluation of medical devices stipulated by ISO standards on biological evaluation of medical devices. Cell culture systems for testing biological reactions to drugs, biomaterials or treatment techniques used in various disciplines have been gaining importance. A wide variety of cell lines are commonly used: cultured fibroblasts from human skin, buccal

C. Wiegand; U.-C. Hipler

2009-01-01

394

Biocompatibility of phosphorylcholine coated stents in normal porcine coronary arteries  

Microsoft Academic Search

OBJECTIVETo improve the biocompatibility of stents using a phosphorylcholine coated stent as a form of biomimicry.INTERVENTIONSImplantation of phosphorylcholine coated (n = 20) and non-coated (n = 21) stents was performed in the coronary arteries of 25 pigs. The animals were killed after five days (n = 6), four weeks (n = 7), and 12 weeks (n = 8), and the

D. M. Whelan; W J van der Giessen; S C Krabbendam; E A van Vliet; P D Verdouw; P W Serruys; H M M van Beusekom

2000-01-01

395

Study on the biocompatibility of in situ vulcanized Silastic 382  

Microsoft Academic Search

The tissue reaction of 4 different implant materials has been compared by Silicon Radiation Measurements in rabbits in order to evaluate the biocompatibility of the in-situ vulcanized Silastic 382. Although the preoperatively vulcanized Silastic 382 elicits less phagocytosis than the in-situ vulcanized Silastic 382, the radiation rates of the latter are similar to the rates obtained from the capsules around

G. Hoinkes; P. Wilflingseder; G. Mikuz; H. Hussl; R. Schlögel; J. C. Bruck

1984-01-01

396

Macrokinetic aspects of the biocompatibility and biodegradation of polymers  

Microsoft Academic Search

We review the quantitative relationships between the degradation kinetics of the main classes of polymers (polyolefins, polyesters, polyamides, elastomers) used as implants. Their biocompatibility criteria and the reactions of the organism on the implants are considered, and the catalytic activity of biological media (water, salts, enzymes) are discussed together with problems in the metabolism and conjugation of the degradation products.

K. Z. Gumargalieva; Gennadii E. Zaikov; Yu V. Moiseev

1994-01-01

397

Surface pretreatment for prolonged survival of cemented tibial prosthesis components: full- vs. surface-cementation technique  

PubMed Central

Background One of few persisting problems of cemented total knee arthroplasty (TKA) is aseptic loosening of tibial component due to degradation of the interface between bone cement and metallic tibial shaft component, particularly for surface cemented tibial components. Surface cementation technique has important clinical meaning in case of revision and for avoidance of stress shielding. Degradation of the interface between bone cement and bone may be a secondary effect due to excessive crack formation in bone cement starting at the opposite metallic surface. Methods This study was done to prove crack formation in the bone cement near the metallic surface when this is not coated. We propose a newly developed coating process by PVD layering with SiOx to avoid that crack formation in the bone cement. A biomechanical model for vibration fatigue test was done to simulate the physiological and biomechanical conditions of the human knee joint and to prove excessive crack formation. Results It was found that coated tibial components showed a highly significant reduction of cement cracking near the interface metal/bone cement (p < 0.01) and a significant reduction of gap formation in the interface metal-to-bone cement (p < 0.05). Conclusion Coating dramatically reduces hydrolytic- and stress-related crack formation at the prosthesis interface metal/bone cement. This leads to a more homogenous load transfer into the cement mantle which should reduce the frequency of loosening in the interfaces metal/bone cement/bone. With surface coating of the tibial component it should become possible that surface cemented TKAs reveal similar loosening rates as TKAs both surface and stem cemented. This would be an important clinical advantage since it is believed that surface cementing reduces metaphyseal bone loss in case of revision and stress shielding for better bone health.

Marx, Rudolf; Qunaibi, Mutaz; Wirtz, Dieter Christian; Niethard, Fritz Uwe; Mumme, Thorsten

2005-01-01

398

Retention of gold alloy crowns cemented with traditional and resin cements.  

PubMed

The aim of this study was to measure in vitro retention of cast gold crowns cemented with traditional and resin cements. Forty-eight human molars were prepared on a lathe to produce complete crown preparations with a consistent taper and split into six groups, eight crowns in each group. Crowns were cast in a high-gold alloy and then cemented. After 24 hours, the retention force (N) was recorded and mean values were analyzed by one-way analysis of variance and the Fisher post-hoc least significant difference (PLSD) multiple comparisons test (a = .05). Failure sites were examined under 3100 magnification and recorded. Mean values (SD) for each group in increasing order of retention force were: Harvard Cement: 43 N (27), TempoCem: 59 N (16), PermaCem Dual: 130 N (42), RelyX Luting Cement: 279 N (26), Contax and PermaCem Dual: 286 N (38), and TempoCem with Contax and PermaCem Dual: 340 N (14). The Fisher PLSD interval (P = .05) for comparing cements was 29 N. Zinc-phosphate cement and provisional resin cements had the lowest retention forces. Resin cement with a bonding agent and the hybrid-ionomer cement had similar retention forces. Resin cement with a bonding agent applied after use of a provisional resin cement had a significantly higher retention force than the other cements tested. PMID:19639070

Pinzón, Lilliam M; Frey, Gary N; Winkler, Mark M; Tate, William H; Burgess, John O; Powers, John M

399

Improvement of initial mechanical strength by nanoalumina in belite cements  

Microsoft Academic Search

The development of new environmentally friendly and energy efficient cements such as belite cements are being promoted due the environmental problems related to CO2 emissions in the manufacture of Portland cement. Although long-term hydrated belite cements show comparable and even better mechanical strength to ordinary Portland hydrated cements, they have low initial mechanical strength, which limits their applicability. In this

I. Campillo; A. Guerrero; J. S. Dolado; A. Porro; J. A. Ibáñez; S. Goñi

2007-01-01

400

Mud to cement technology proven in offshore drilling project  

Microsoft Academic Search

One problem with conventional cements is the incompatibility of Portland cement and the drilling mud. Expensive preflushes and spacer fluids have been used, often with limited success, to attempt to separate mud and Portland cement effectively. Under downhole conditions, most spacers are ineffective in preventing high viscosities and cement contamination problems which lead to poor primary cement jobs. One solution

K. Javanmardi; K. D. Flodberg; J. J. Nahm

1993-01-01

401

Calculator programs replace cementing tables  

SciTech Connect

Two programs written for use on the two most popular programmable calculators solve routine volume and fill problems using data available on the drill floor. And while those familiar books of cementing tables should be kept for special jobs, the programs given here provide quick solutions to everyday cementing problems. Programs are presented for the solution of annular volume and pipe and hole capacity problems using the TI-59 or any of the Hewlett-Packard programmable calculators. The TI program was written for use with the PC-100C printer to prompt for input data and label output. A procedure is presented to modify this for hand-held operation using storage register numbers for prompts and to recall output information from storage registers. The program using the printer is discussed first.

Landry, W.E.

1987-01-01

402

The density of cement phases  

SciTech Connect

The densities of principal crystalline phases occurring in Portland cement are critically assessed and tabulated, in some cases with addition of new data. A reliable and self-consistent density set for crystalline phases was obtained by calculating densities from crystallographic data and unit cell contents. Independent laboratory work was undertaken to synthesize major AFm and AFt cement phases, determine their unit cell parameters and compare the results with those recorded in the literature. Parameters were refined from powder diffraction patterns using CELREF 2 software. A density value is presented for each phase, showing literature sources, in some cases describing limitations on the data, and the weighting attached to numerical values where an averaging process was used for accepted data. A brief discussion is made of the consequences of the packing of water to density changes in AFm and AFt structures.

Balonis, M. [Department of Chemistry, Meston Building, University of Aberdeen, Aberdeen, AB24 3UE, Scotland (United Kingdom)], E-mail: m.balonis@abdn.ac.uk; Glasser, F.P. [Department of Chemistry, Meston Building, University of Aberdeen, Aberdeen, AB24 3UE, Scotland (United Kingdom)

2009-09-15

403

Effects of cement particle size distribution on performance properties of Portland cement-based materials  

SciTech Connect

The original size, spatial distribution, and composition of Portland cement particles have a large influence on hydration kinetics, microstructure development, and ultimate properties of cement-based materials. In this paper, the effects of cement particle size distribution on a variety of performance properties are explored via computer simulation and a few experimental studies. Properties examined include setting time, heat release, capillary porosity percolation, diffusivity, chemical shrinkage, autogenous shrinkage, internal relative humidity evolution, and interfacial transition zone microstructure. The effects of flocculation and dispersion of the cement particles in the starting microstructures on resultant properties are also briefly evaluated. The computer simulations are conducted using two cement particle size distributions that bound those commonly in use today and three different water-to-cement ratios: 0.5, 0.3, and 0.246. For lower water-to-cement ratio systems, the use of coarser cements may offer equivalent or superior performance, as well as reducing production costs for the manufacturer.

Bentz, D.P.; Garboczi, E.J.; Haecker, C.J.; Jensen, O.M.

1999-10-01

404

Evaluation of Hazardous Waste Incineration in Cement Kilns at San Juan Cement Company.  

National Technical Information Service (NTIS)

Cement kiln incineration of chlorinated liquid organic wastes was investigated in a 5-month demonstration program at San Juan Cement Company in Puerto Rico. Chlorinated monocarbon compounds (POHC's) were monitored in the waste and emissions, and the fate ...

J. A. Peters T. W. Hughes J. R. McKendree L. A. Cox B. M. Hughes

1984-01-01

405

Cementing steamflood and fireflood wells - slurry design  

SciTech Connect

Steamflood and fireflood wells present special challenges when designing a cement slurry. In most cases, the cement slurry is subjected to relatively low temperature during the cement job and early curing. However, after the cement sets, it must be able to withstand the thermal shock associated with the initiation of steamflooding or fireflooding. In addition, the cement must be able to preserve adequate compressive strength and low permeability despite the potentially disruptive crystalline changes that occur at high temperatures. Another complicating factor is the weak or incompetent formations often encountered with thermal recovery wells. This work discusses the chemical and phase equilibria relationships which prevail when cements are exposed to the high temperatures associated with fireflood and steamflood wells.

Nelson, E.B.; Eilers, L.H.

1983-01-01

406

Sustainable cement production-present and future  

SciTech Connect

Cement will remain the key material to satisfy global housing and modern infrastructure needs. As a consequence, the cement industry worldwide is facing growing challenges in conserving material and energy resources, as well as reducing its CO{sub 2} emissions. According to the International Energy Agency, the main levers for cement producers are the increase in energy efficiency and the use of alternative materials, be it as fuel or raw materials. Accordingly, the use of alternative fuels has already increased significantly in recent years, but potential for further increases still exists. In cement, the reduction of the clinker factor remains a key priority: tremendous progress has already been made. Nevertheless, appropriate materials are limited in their regional availability. New materials might be able to play a role as cement constituents in the future. It remains to be seen to what extent they could substitute Portland cement clinker to a significant degree.

Schneider, M., E-mail: sch@vdz-online.de [VDZ, Duesseldorf (Germany); Romer, M.; Tschudin, M. [Holcim Group Support Ltd, Holderbank (Switzerland); Bolio, H. [CEMEX, Monterrey (Mexico)

2011-07-15

407

Porous calcium phosphate cement for alveolar bone regeneration.  

PubMed

The present study aimed to provide information on material degradation and subsequent alveolar bone formation, using composites consisting of calcium phosphate cement (CPC) and poly(lactic-co-glycolic) acid (PLGA) with different microsphere morphology (hollow vs dense). In addition to the plain CPC-PLGA composites, loading the microspheres with the growth factors platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF) was investigated. A total of four different CPC composites were applied into one-wall mandible bone defects in beagle dogs in order to evaluate them as candidates for alveolar bone regeneration. These composites consisted of CPC and hollow or dense PLGA microspheres, with or without the addition of PDGF-IGF growth factor combination (CPC-hPLGA, CPC-dPLGA, CPC-hPLGA(GF) , CPC-dPLGA(GF) ). Histological evaluation revealed significantly more bone formation in CPC-dPLGA than in CPC-hPLGA composites. The combination PDGF-IGF enhanced bone formation in CPC-hPLGA materials, but significantly more bone formation occurred when CPC-dPLGA was used, with or without the addition of growth factors. The findings demonstrated that CPC-dPLGA composite was the biologically superior material for use as an off-the-shelf material, due to its good biocompatibility, enhanced degradability and superior bone formation. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22777771

Félix Lanao, R P; Hoekstra, J W M; Wolke, J G C; Leeuwenburgh, S C G; Plachokova, A S; Boerman, O C; van den Beucken, J J J P; Jansen, J A

2012-07-01

408

The leachability of heavy metals in hardened fly ash cement and cement-solidified fly ash  

Microsoft Academic Search

The effect of mix proportion, leachant pH, curing age, carbonation and specimen making method etc. on the leaching of heavy metals and Cr(VI) in fly ash cement mortars and cement-solidified fly ashes has been investigated. In addition, a method for reducing the leaching of Cr(VI) from cement-solidified fly ashes is proposed. The results mainly indicate that: (1) either Portland cement

Qijun Yu; S. Nagataki; Jinmei Lin; T. Saeki; M. Hisada

2005-01-01

409

Nanofunctionalized zirconia and barium sulfate particles as bone cement additives  

PubMed Central

Zirconia (ZrO2) and barium sulfate (BaSO4) particles were introduced into a methyl methacrylate monomer (MMA) solution with polymethyl methacrylate (PMMA) beads during polymerization to develop the following novel bone cements: bone cements with unfunctionalized ZrO2 micron particles, bone cements with unfunctionalized ZrO2 nanoparticles, bone cements with ZrO2 nanoparticles functionalized with 3-(trimethoxysilyl)propyl methacrylate (TMS), bone cements with unfunctionalized BaSO4 micron particles, bone cements with unfunctionalized BaSO4 nanoparticles, and bone cements with BaSO4 nanoparticles functionalized with TMS. Results demonstrated that in vitro osteoblast (bone-forming cell) densities were greater on bone cements containing BaSO4 ceramic particles after four hours compared to control unmodified bone cements. Osteoblast densities were also greater on bone cements containing all of the ceramic particles after 24 hours compared to unmodified bone cements, particularly those bone cements containing nanofunctionalized ceramic particles. Bone cements containing ceramic particles demonstrated significantly altered mechanical properties; specifically, under tensile loading, plain bone cements and bone cements containing unfunctionalized ceramic particles exhibited brittle failure modes whereas bone cements containing nanofunctionalized ceramic particles exhibited plastic failure modes. Finally, all bone cements containing ceramic particles possessed greater radio-opacity than unmodified bone cements. In summary, the results of this study demonstrated a positive impact on the properties of traditional bone cements for orthopedic applications with the addition of unfunctionalized and TMS functionalized ceramic nanoparticles.

Gillani, Riaz; Ercan, Batur; Qiao, Alex; Webster, Thomas J

2010-01-01

410

The nature of CSH in hardened cements  

Microsoft Academic Search

Calcium silicate hydrates (C-S-H) are the main binding phases in all Portland cement-based systems. This paper considers the morphology, composition, and nanostructure of C-S-H in a range of hardened cements. Inner product (Ip) C-S-H present in larger Portland cement grains typically has a fine-scale and homogeneous morphology with pores somewhat under 10 nm in diameter. Ip from larger slag grains

I. G Richardson

1999-01-01

411

Retention of metal ceramic crowns cemented with resin cements: Effects of preparation taper and height  

Microsoft Academic Search

This study investigated the effect of varying crown preparation taper and height on the retention of metal ceramic crowns cemented with resin cements. In part 1, 32 extracted molars were divided into four groups. All groups received complete-veneer crown preparations, two with a 12-degree wall angle and two with a 35-degree wall angle. Crowns were cemented with zinc phosphate and

Omar M El-Mowafy; Aaron H Fenton; Nicola Forrester; Miroslava Milenkovic

1996-01-01

412

General hydration model for portland cement and blast furnace slag cement  

Microsoft Academic Search

This paper focusses on the evolution of the heat of hydration of hardening concrete or cement based materials. Based on isothermal and adiabatic hydration tests a new general hydration model is developed, valid both for portland cement and blast furnace slag cement. This hydration model enables the calculation of the heat production rate as a function of the actual temperature

L. Taerwe

1995-01-01

413

Tooth-colored inlays: new cementation technique.  

PubMed

A new technique for tooth-colored inlay cementation is introduced. Dual-cure fully filled restorative resin Sono-Cem (ESPE America, Norristown, PA) was used to cement tooth-colored restoration. A specially designed wooden tip in the gently vibrating Profin handpiece (Dentatus USA, New York) may be considered an excellent instrument for cementing porcelain and composite inlays with Sono-Cem cement. Also, a wide variety of diamond/tungsten plated abrasive Lamineer tips in a Profin Handpiece may be used for tooth preparation as well as for finishing restorations. PMID:9515433

Zhukovsky, L; Settembrini, L; Epelboym, D

414

Well cementing process using presheared water swellable clays  

SciTech Connect

A method of preparing and using a cement slurry having water swellable clays therein as extenders for the cement is described. This method enhances the effectiveness of the water swellable clays by preshearing aqueous suspensions thereof prior to mixing these suspensions with cement to form a pumpable cement slurry. Also described is a particular technique for using bentonite as a cement extender in a cement slurry formed with salt water.

Messenger, J.U.

1980-05-13

415

Biocompatibility evaluation of nano hydroxyapatite-starch biocomposites.  

PubMed

In this work, we report the synthesis and characterization of nano hydroxyapatite (nHAp) in the presence of starch matrix via a biomimetic process for in vitro biocompatibility evaluation. Characterization of the samples was carried out using X-ray diffraction (XRD) and Fourier Transform infrared spectroscopy (FT-IR). The Size and morphology of the nHAp samples were determined using scanning and transmission electron microscopy (SEM and TEM). The results show that, the shape and morphology of nHAp is influenced by the presence of starch as a template agent. It leads to formation of rod-like nHAp. Cell culture and MTT assays were performed for in vitro biocompatibility. They show that n-HAp can affect the proliferation of cells and the n-HAp/starch biocomposites have no negative effect on the cell morphology, viability and proliferation. PMID:21830489

Meskinfam, M; Sadjadi, M A S; Jazdarreh, H; Zare, K

2011-06-01

416

Method for making a bio-compatible scaffold  

DOEpatents

A method for forming a three-dimensional, biocompatible, porous scaffold structure using a solid freeform fabrication technique (referred to herein as robocasting) that can be used as a medical implant into a living organism, such as a human or other mammal. Imaging technology and analysis is first used to determine the three-dimensional design required for the medical implant, such as a bone implant or graft, fashioned as a three-dimensional, biocompatible scaffold structure. The robocasting technique is used to either directly produce the three-dimensional, porous scaffold structure or to produce an over-sized three-dimensional, porous scaffold lattice which can be machined to produce the designed three-dimensional, porous scaffold structure for implantation.

Cesarano, III, Joseph (Albuquerque, NM); Stuecker, John N. (Albuquerque, NM); Dellinger, Jennifer G. (Champaigne, IL); Jamison, Russell D. (Urbana, IL)

2006-01-31

417

Magnesium-based composites with improved in vitro surface biocompatibility  

PubMed Central

In this study, bioactive glass (BG, 45S5) particles were added to a biodegradable magnesium alloy (ZK30) through a semi-solid high-pressure casting process in order to improve the surface biocompatibility of the biomaterial and potentially its bioactivity. The observation of the as-cast microstructures of ZK30-BG composites indicated homogeneous dispersion of BG particles in the matrix. SEM, EDX and EPMA showed the retention of the morphological characteristics and composition of BG particles in the as-cast composite materials. In vitro tests in a cell culture medium confirmed that the composites indeed possessed an enhanced ability to induce the deposition of a bone-like apatite layer on the surface, indicating an improved surface biocompatibility as compared with the matrix alloy.

Huan, Zhiguang; Duszczyk, Jurek

2010-01-01

418

Biocompatibility studies of polyacrylonitrile membranes modified with carboxylated polyetherimide.  

PubMed

Poly (ether-imide) (PEI) was carboxylated and used as the hydrophilic modification agent for the preparation of polyacrylonitrile (PAN) membranes. Membranes were prepared with different blend compositions of PAN and CPEI by diffusion induced precipitation. The modified membranes were characterized by thermo gravimetric analysis (TGA), mechanical analysis, scanning electron microscopy (SEM) and contact angle measurement to understand the influence of CPEI on the properties of the membranes. The biocompatibility studies exhibited reduced plasma protein adsorption, platelet adhesion and thrombus formation on the modified membrane surface. The complete blood count (CBC) results of CPEI incorporated membranes showed stable CBC values and significant decrease in the complement activation were also observed. In addition to good cytocompatibility, monocytes cultured on these modified membranes exhibited improved functional profiles in 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Thus it could be concluded that PAN/CPEI membranes with excellent biocompatibility can be useful for hemodialysis. PMID:23910257

Senthilkumar, S; Rajesh, S; Jayalakshmi, A; Mohan, D

2013-04-30

419

BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES  

SciTech Connect

Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

Farquar, G; Leif, R

2009-07-15

420

Biocompatible and detectable carboxylated nanodiamond on human cell  

Microsoft Academic Search

Surface-modified carboxylated nanometre-sized diamond (cND) has been applied for the conjugation of biological molecules such as DNA and protein. In this study, we evaluated the biocompatibility and detection of cNDs and carbon nanotubes on human lung A549 epithelial cells and HFL-1 normal fibroblasts. Treatment with 5 or 100 nm cND particles, 0.1-100 µg ml-1, did not reduce the cell viability

Kuang-Kai Liu; Chia-Liang Cheng; Chia-Ching Chang; Jui-I. Chao

2007-01-01

421

Biocompatible polymer alloy membrane for implantable artificial pancreas  

Microsoft Academic Search

The preparation of a novel polymer alloy membrane with both biocompatibility and permeability for fabrication of an implantable artificial pancreas was carried out. The polymer alloy was composed of a segmented polyurethane (SPU) and phospholipid polymer with 2-methacryloyloxyethyl phosphorylcholine (MPC) units. The MPC polymer was poly(MPC-co-2-ethylhexyl methacrylate) (PMEH), which can be dissolved in the same solvent for SPU. The SPU\\/PMEH

Tomoaki Uchiyama; Junji Watanabe; Kazuhiko Ishihara

2002-01-01

422

Biosynthesis of biocompatible cadmium telluride quantum dots using yeast cells  

Microsoft Academic Search

We demonstrate a simple and efficient biosynthesis method to prepare easily harvested biocompatible cadmium telluride (CdTe)\\u000a quantum dots (QDs) with tunable fluorescence emission using yeast cells. Ultraviolet-visible (UV-vis) spectroscopy, photoluminescence\\u000a (PL) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM) confirm that the CdTe QDs are formed\\u000a via an extracellular growth and subsequent endocytosis pathway and have size-tunable optical properties

Haifeng Bao; Na Hao; Yunxia Yang; Dongyuan Zhao

2010-01-01

423

Effect of surface treatment on the biocompatibility of microbial polyhydroxyalkanoates  

Microsoft Academic Search

The biocompatibility of microbial polyesters polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) were evaluated in vitro. The mouse fibroblast cell line L929 was inoculated on films made of PHB, PHBHHx and their blends, polylactic acid (PLA) as control. It was found that the growth of the cells L929 was poor on PHB and PLA films. The viable cell number ranged from 8.8×102

Xianshuang Yang; Kai Zhao; Guo-Qiang Chen

2002-01-01

424

Mesh biocompatibility: effects of cellular inflammation and tissue remodelling  

Microsoft Academic Search

Mesh biocompatibility is basically determined by the foreign body reaction (FBR). In contrast to physiological wound healing\\u000a and scar formation, the FBR at the host-tissue\\/biomaterial interface is present for the lifetime of the medical device. The\\u000a cellular interactions at the mesh\\/tissue interface proceed over time ending up in a chronic inflammatory process. The time\\u000a course of the FBR has been

Karsten Junge; Marcel Binnebösel; Klaus T. von Trotha; Raphael Rosch; Uwe Klinge; Ulf P. Neumann; Petra Lynen Jansen

425

Engineering biomaterials to integrate and heal: the biocompatibility paradigm shifts.  

PubMed

This article focuses on one of the major failure routes of implanted medical devices, the foreign body reaction (FBR)--that is, the phagocytic attack and encapsulation by the body of the so-called "biocompatible" biomaterials comprising the devices. We then review strategies currently under development that might lead to biomaterial constructs that will harmoniously heal and integrate into the body. We discuss in detail emerging strategies to inhibit the FBR by engineering biomaterials that elicit more biologically pertinent responses. PMID:22592568

Bryers, James D; Giachelli, Cecilia M; Ratner, Buddy D

2012-05-24

426

Permeability and Biocompatibility of Novel Medicated Hydrogel Wound Dressings  

Microsoft Academic Search

Hydrogel dressings are being popularized for wound care management because of their softness, tissue compatibility, and ability to enhance wound healing process. PVP-CMC and PVP-CMC-BA hydrogels were prepared using polyvinylpyrrolidone (PVP), sodium-carboxymethylcellulose (CMC), polyethyleneglycol (PEG), agar, glycerine and without\\/with boric acid (BA). Permeability: water vapor transmission and microbe penetration and biocompatibility: cytotoxicity, skin irritation, and skin sensitization tests of hydrogels

Niladri Roy; Nabanita Saha; Petr Humpolicek; Petr Saha

2010-01-01

427

Development of novel biocompatible hydrogel coatings for implantable glucose sensors  

Microsoft Academic Search

Due to sensor -tissue interactions, currently none of the commercially available glucose sensors are capable of continuous, reliable monitoring of glucose levels during long-term implantation. In order to improve the lifetime of implanted glucose sensors, two series of biocompatible novel hydrogel coatings were designed, synthesized and the physical properties were measured. Different hydrogels with various 2,3-dihydroxypropyl methacrylate (DHPMA) compositions were

Chunyan Wang

2008-01-01

428

Incorporation of optical enzymatic sensing chemistry into biocompatible hydrogels  

Microsoft Academic Search

Oxidative enzymes coupled with analyte-sensitive luminophores present a way to optically transduce levels of biochemical substrates. In combination with implantable biocompatible materials, such sensing chemistry could become a powerful tool in the continuous monitoring of analytes in a non-invasive manner. This work presents model optical sensing systems containing the enzyme glucose oxidase (GOx) and an oxygen-sensitive or pH-sensitive luminophore incorporated

Jason Roberts; Bradley B. Collier; Michael J. McShane

2011-01-01

429

Corrosion and biocompatibility testing of palladium alloy castings  

Microsoft Academic Search

Objectives: The biocompatibility of palladium–copper alloys has been questioned in the literature. The intention of the present work was to study: (a) the release of ions in an immersion test from a copper-containing alloy, Option® (79% Pd, 10% Cu, 9% Ga, 2% Au), compared with an alloy without Cu, IS85 (82% Pd, 6% Ga, 3.5% Sn, 3.5% In, 2.5% Ag,

M Syverud; J. E Dahl; H Herø; E Morisbak

2001-01-01

430

New tubular bioabsorbable knitted airway stent: Biocompatibility and mechanical strength  

Microsoft Academic Search

Objective: This study examines the biocompatibility and suitability of a new tubular bioabsorbable knitted stent made of poly-L-lactic acid in normal rabbit airways and examines the mechanical strength of this stent in vitro. Methods: A tubular knitted airway stent (group B, n = 15) made of poly-L-lactic acid wire was implanted operatively in New Zealand White rabbits intratracheally; silicone stents

Yukihito Saito; Kenichirou Minami; Masashi Kobayashi; Yoshihisa Nakao; Hideyasu Omiya; Hiroji Imamura; Noriko Sakaida; Akiharu Okamura

2002-01-01

431

Concepts in biocompatibility testing of dental restorative materials  

Microsoft Academic Search

Due to the diversity of adverse biological effects which might be caused by dental restorative materials, biocompatibility\\u000a assessment cannot rely on a single test but has to be based on a planned and structured approach (concept). First, the possible\\u000a harm evoked by the material, the known data, and suitable biological and other test methods available must be taken into consideration.

G. Schmalz

1998-01-01

432

Highly flexible and biocompatible Carbon Nanotube thin film transistors  

Microsoft Academic Search

We demonstrate a highly flexible and biocompatible Single-Walled Carbon Nanotube (SWNT) based thin film transistor (TFT). These devices were fabricated on a parylene-C substrate (10¿m) and encapsulated from the environment with a 1¿m thick parylene-C layer. Carbon nanotube (CNT) TFT was realized by field assisted (dielectrophoretic) assembly followed by electrical breakdown of SWNTs at room temperature. These SWNT TFTs exhibited

S. Selvarasah; K. Anstey; S. Somu; A. Busnaina; M. R. Dokmeci

2009-01-01

433

A Comparative Biocompatibility Analysis of Ternary Nitinol Alloys  

NASA Astrophysics Data System (ADS)

Nitinol alloys are rapidly being utilized as the material of choice in a variety of applications in the medical industry. It has been used for self-expanding stents, graft support systems, and various other devices for minimally invasive interventional and endoscopic procedures. However, the biocompatibility of this alloy remains a concern to many practitioners in the industry due to nickel sensitivity experienced by many patients. In recent times, several new Nitinol alloys have been introduced with the addition of a ternary element. Nevertheless, there is still a dearth of information concerning the biocompatibility and corrosion resistance of these alloys. This study compared the biocompatibility of two ternary Nitinol alloys prepared by powder metallurgy (PM) and arc melting (AM) and critically assessed the influence of the ternary element. ASTM F 2129-08 cyclic polarization in vitro corrosion tests were conducted to evaluate the corrosion resistance in phosphate buffered saline (PBS). The growth of endothelial cells on NiTi was examined using optical microscopy.

Haider, Waseem; Munroe, Norman; Pulletikurthi, Chandan; Gill, Puneet K. Singh; Amruthaluri, Sushma

2009-08-01

434