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1

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

2

Bond strength of resin cements to zirconia conditioned with primers.  

PubMed

New ceramic primers, which reportedly enhance bonding of resin cements to zirconia, have been marketed recently. The purpose of this study was to compare the shear bond strength of 3 resin cements to zirconia conditioned with 4 ceramic primers. Zirconia blocks were conditioned with 4 different primers (Z-Prime Plus, MonoBond Plus, CLEARFIL CERAMIC PRIMER, and AZ Primer) or no primer (control). The zirconia blocks were placed in a jig, and 1 of 3 resin cements (Multilink Automix, RelyX Unicem, Panavia F 2.0) were mixed, injected into a mold, and light cured. The specimens were tested in shear on a universal testing machine after 24 hours of storage in distilled water. The shear bond strength of the resin cements to zirconia varied based on the type of primer. Z-Prime Plus provided the highest shear bond strength to zirconia, and was significantly greater than the control (no primer) with all 3 resin cements. PMID:24064168

Kobes, Kurtis G; Vandewalle, Kraig S

3

Adhesive bonding of resin cements to cast titanium with adhesive primers.  

PubMed

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 ? m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (?=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used. PMID:22814689

Di Francescantonio, Marina; Oliveira, Marcelo Tavares de; Daroz, Luiz Gustavo Dias; Henriques, Guilherme Elias Pessanha; Giannini, Marcelo

2012-01-01

4

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

5

In vitro comparative bond strength of contemporary self-adhesive resin cements to zirconium oxide ceramic with and without air-particle abrasion  

Microsoft Academic Search

This study compared shear bond strengths of six self-adhesive resin cements to zirconium oxide ceramic with and without air-particle\\u000a abrasion. One hundred twenty zirconia samples were air-abraded (group SB; n?=?60) or left untreated (group NO). Composite cylinders were bonded to the zirconia samples with either BisCem (BC), Maxcem\\u000a (MC), G-Cem (GC), RelyX Unicem Clicker (RUC), RelyX Unicem Applicator (RUA), or

Markus B. Blatz; Jin-Ho Phark; Fusun Ozer; Francis K. Mante; Najeed Saleh; Michael Bergler; Avishai Sadan

2010-01-01

6

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

7

The effect of dentin desensitizer on shear bond strength of conventional and self-adhesive resin luting cements after aging.  

PubMed

This study tested the impact of Gluma Desensitizer on the shear bond strength (SBS) of two conventional (RelyX ARC, Panavia 21) and two self-adhesive (RelyX Unicem, G-Cem) resin luting cements after water storage and thermocycling. Human third molars (N=880) were embedded in acrylic resin. The buccal dentin was exposed. Teeth were randomly divided into four main groups, and the following cements were adhered: 1) RelyX ARC, 2) Panavia 21, 3) RelyX Unicem, and 4) G-Cem. In half of the teeth in each group, dentin was treated with Gluma Desensitizer. In the conventional cement groups, the corresponding etchant and adhesive systems were applied. SBS of the cements was tested after 1 hour (initial); at 1, 4, 9, 16, and 25 days of water storage; and at 1, 4, 9, 16, and 25 days of thermocycling. SBS data were analyzed by one-way analysis of variance (ANOVA); this was followed by the post hoc Scheffé test and a t-test. Overall, the highest mean SBS (MPa) was obtained by RelyX ARC (ranging from 14.6 ± 3.9 to 17.6 ± 5.2) and the lowest by Panavia 21 in combination with Gluma Desensitizer (ranging from 0.0 to 2.9 ± 1.0). All tested groups with and without desensitizer showed no significant decrease after aging conditions compared with baseline values (p>0.05). Only the Panavia 21/Gluma Desensitizer combination showed a significant decrease after 4 days of thermocyling compared with initial values and 1 day thermocycling. Self-adhesive cements with Gluma Desensitizer showed increased SBS after aging conditions (ranging from 7.4 ± 1.4 to 15.2 ± 3) compared with groups without desensitizer (ranging from 2.6 ± 1.2 to 8.8 ± 2.9). No cohesive failures in dentin were observed in any of the test groups. Although self-adhesive cements with and without desensitizer presented mainly adhesive failures after water storage (95.8%) and thermocyling (100%), conventional cement (RelyX ARC) showed mainly mixed failures (90.8% and 89.2%, after water storage and thermocyling, respectively). Application of the Gluma Desensitizer to dentin before cementation had a positive effect on the SBS of self-adhesive cements. PMID:21843027

Stawarczyk, B; Hartmann, R; Hartmann, L; Roos, M; Ozcan, M; Sailer, I; Hämmerle, C H F

2011-08-15

8

Effect of operator experience on the outcome of fiber post cementation with different resin cements.  

PubMed

SUMMARY Objectives : To evaluate the influence of operator experience (dentist vs student) and cementation system (Adper Scotchbond Multi-Purpose [SBMP] + RelyX ARC [1]; Adper Single Bond 2 [SB] + RelyX ARC [2] and RelyX U100 [3]) on the push-out bond strength (BS) of fiber post to radicular dentin. Materials and Methods : The roots of 48 extracted human maxillary central incisors were prepared and divided into six groups (n=8), according to combination of the above factors. Glass fiber posts were cemented in accordance with the instructions of the manufacturer of each cementation system. After water storage at 37°C for one week, the roots were cross-sectioned into six 1-mm thick slices and the push-out test was performed (0.5 mm/min). Data were statistically analyzed by two-way analysis of variance and Tukey tests (?=0.05). The BS results obtained by dentist and student for each cementation system were compared using the Student t-test (?=0.05). Results : Higher BS means were observed for the expert operators, irrespective of the cementation system used (p=0.006). RelyX U100 showed the highest bond strength, but it did not differ from SBMP + RelyX ARC. The Student t-test revealed that only RelyX U100 was not affected by the operator's experience. Conclusion : Within the limitations of this in vitro study, it can be concluded that the self-adhesive cement RelyX U100 showed the highest bond strength to the root canal in the student's group, and its performance was not affected by the operator's experience. PMID:23216469

Gomes, Gm; Gomes, Omm; Reis, A; Gomes, Jc; Loguercio, Ad; Calixto, Al

2012-12-05

9

Effect of ceramic veneer opacity and exposure time on the polymerization efficiency of resin cements.  

PubMed

The objective of this study was to determine the degree of conversion (DC), hardness (H), and modulus of elasticity (E) of a dual-cured resin cement, a light-cured resin cement, and a flowable resin cured through opaque or translucent ceramic with different exposure times. RelyX ARC (dual), RelyX Veneer (light-cured), and Filtek Z350 Flow resin specimens 0.5 mm thick were cured for 40, 80, and 120 seconds through 1-mm thick translucent or opaque feldspathic ceramic disks (n=10). The specimens were stored at 37°C for 24 hours. Half of each specimen was used to test the DC and the other half to test H and E. The DC was determined in a Fourier transform infrared spectrometer in absorbance mode at peaks of 1638 cm(-1) and 1610 cm(-1). H and E were determined using nanoindentation with one loading cycle and a maximum load of 400 mN. The data were analyzed with three-way analysis of variance (ANOVA), the Games-Howell test, and the Pearson correlation test (?=0.05). Statistically significant differences were found for all three factors (material, opacity, and exposure time), as well as interaction between them. The opaque ceramic resulted in lower DC, H, and E than the translucent ceramic for an exposure time of 40 seconds. An exposure time of 120 seconds resulted in a similar DC for all materials, irrespective of the opacity of the ceramic. Materials cured for 120 seconds had higher H and E than those cured for 40 seconds. The exposure time and opacity of the ceramic exerted an influence on the DC, H, and E of the materials evaluated. PMID:22313282

Archegas, Lucí Regina Panka; de Menezes Caldas, Danillo Biazzetto; Rached, rodrigo Nunes; Soares, Paulo; Souza, Evelise Machado

2012-02-07

10

Shear and tensile bond testing for resin cement evaluation  

Microsoft Academic Search

Objectives. The aim of this study was to compare the tensile and shear bond strengths of one experimental and four commercially available resin cements following the ISO document TR 110405 for bond measurement.Methods. Tensile and shear bond tests were performed using bovine enamel and dentin as the tooth substrate with each of the resin cements. Resin composite rods were cemented

Yuichi Kitasako; Michael F. Burrow; Toru Nikaido; Naoko Harada; Shigehisa Inokoshi; Toshimoto Yamada; Toshio Takatsu

1995-01-01

11

Effect of Surface Modification on the Bond Strength between Zirconia and Resin Cement.  

PubMed

PURPOSE: This study aimed to evaluate the micro push-out (?-PO) bond strength between zirconia and resin cement after addition of zirconia particles to increase the surface roughness. MATERIALS AND METHODS: Y-TZP zirconia specimens in three experimental groups were subjected to Y-TZP particle deposition via dipping into the milling residue suspension at different times prior to the sintering process. The dipping procedure was repeated twice for each specimen in group B, six times in group C, and ten times in group D. The specimens subjected to airborne-particle abrasion (110 ?m Al2 O3 , Rocatec Pre) acted as the control group (group A). All of the specimens were then bonded using adhesive resin cement (RelyX Ultimate). A ?-PO test was used to determine the bond strength values. One-way ANOVA at a 5% confidence level was performed for data analysis. Optical microscopy and scanning electron microscopy (SEM) were used to evaluate the failure modes and surface structure. RESULTS: Y-TZP particle deposition did not have a significant effect on the bond strength of the resin cement to zirconia specimens when compared to the control (p = 0.141). Higher bond strength values were observed in groups C and D than in control. The surface layer presented blister-like porosities with openings of various diameters ranging between 2 and 4 ?m. CONCLUSION: Y-TZP particle deposition after dipping six and ten times did not improve the mean bond strength statistically but presented surface topography that may be favorable for increased micromechanical retention for adhesive resin cement. CLINICAL SIGNIFICANCE: Y-TZP particle deposition may create a more retentive surface than airborne-particle abrasion for adhesive bonding between zirconia surface and resin cement. PMID:23551581

Egilmez, Ferhan; Ergun, Gulfem; Cekic-Nagas, Isil; Vallittu, Pekka K; Ozcan, Mutlu; Lassila, Lippo V J

2013-04-01

12

Light transmittance of zirconia as a function of thickness and microhardness of resin cements under different thicknesses of zirconia  

PubMed Central

Objective: The objective of this study was to compare microhardness of resin cements under different thicknesses of zirconia and the light transmittance of zirconia as a function of thickness. Study design: A total of 126 disc-shaped specimens (2 mm in height and 5 mm in diameter) were prepared from dual-cured resin cements (RelyX Unicem, Panavia F and Clearfil SA cement). Photoactivation was performed by using quartz tungsten halogen and light emitting diode light curing units under different thicknesses of zirconia. Then the specimens (n=7/per group) were stored in dry conditions in total dark at 37°C for 24 h. The Vicker’s hardness test was performed on the resin cement layer with a microhardness tester. Statistical significance was determined using multifactorial analysis of variance (ANOVA) (alpha=.05). Light transmittance of different thicknesses of zirconia (0.3, 0.5 and 0.8 mm) was measured using a hand-held radiometer (Demetron, Kerr). Data were analyzed using one-way ANOVA test (alpha=.05). Results: ANOVA revealed that resin cement and light curing unit had significant effects on microhardness (p < 0.001). Additionally, greater zirconia thickness resulted in lower transmittance. There was no correlation between the amount of light transmitted and microhardness of dual-cured resin cements (r = 0.073, p = 0.295). Conclusion: Although different zirconia thicknesses might result in insufficient light transmission, dual-cured resin cements under zirconia restorations could have adequate microhardness. Key words:Zirconia, microhardness, light transmittance, resin cement.

Egilmez, Ferhan; Ergun, Gulfem; Kaya, Bekir M.

2013-01-01

13

Push-out strength of fiber posts depending on the type of root canal filling and resin cement  

Microsoft Academic Search

The purpose of this study was to analyze the push-out strength of two fiber post systems\\/resin cements (RelyX Unicem\\/RelyX\\u000a Fiber Post (RLX) and Variolink II\\/DT Light SL (VL)) depending on the root canal filling (RF). One hundred sixty extracted\\u000a human teeth were divided into four groups: gutta-percha\\/AH Plus (GP), gutta-percha\\/Guttaflow (GF), pre-existing root canal\\u000a filling (PRF), and without root canal

Maria Dimitrouli; Hüsamettin Günay; Werner Geurtsen; Anne-Katrin Lührs

2011-01-01

14

Push-out bond strengths of fiber-reinforced composite posts with various resin cements according to the root level  

PubMed Central

PURPOSE The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P<.05). Only the Uni and LuA cements did not show any significant decrease in their bond strengths at all the root levels (P>.05); all other groups had a significant decrease in bond strength at the middle or apical level (P<.05). The failure aspect was dominantly cohesive at the coronal level of all resin cements (P<.05), whereas it was dominantly adhesive at the apical level. CONCLUSION All resin cement groups showed decreases in bond strengths at the middle or apical level except LuA and Uni.

Chang, Hoon-Sang; Noh, Young-Sin; Lee, Yoon; Min, Kyung-San

2013-01-01

15

Influence of plasma pretreatment on shear bond strength of self-adhesive resin cements to polyetheretherketone.  

PubMed

OBJECTIVES: The aim of this study is to evaluate the adhesion between PEEK and two self-adhesive resin cements after plasma treatment. METHODS: Eight hundred sixty-four polyetheretherketone (PEEK) disks were cut and polished to silicon carbide (SIC) P4000. One half of the specimens were randomly selected and pretreated with plasma, whereas the remaining 432 specimens remained untreated. Subsequently, specimens were randomly allocated to four groups (n?=?108/group): Visio.link (Bredent), Signum PEEK Bond (Heraeus Kulzer), Ambarino P60 (Creamed), and a control group without additional treatment. Half of the specimens of each group (n?=?54) were then cemented with either RelyX Unicem Automix 2 (3 M ESPE) or with Clearfil SA (Kuraray). All specimens were stored in water for 24 h (37 °C). Afterwards, specimens were divided into three groups (n?=?18) for different aging levels: (1) no aging (baseline measurement), (2) thermal aging for 5,000 cycles (5/55 °C), and (3) thermal aging for 10,000 cycles (5/55 °C). Thereafter, shear bond strengths (SBS) were measured, and failure types (adhesive, mixed, and cohesive) were assessed. Data were analyzed using descriptive statistics, four- and one-way ANOVA followed by a post hoc Scheffé test (p?resin cements used. In general, no cohesive failures were observed. Groups without plasma treatment combined with Visio.link or Signum PEEK Bond showed predominantly mixed failure types. Control groups, plasma treated, or treated using Ambarino P60 groups fractured predominantly adhesively. CONCLUSION: The use of methyl methacrylate (MMA)-based adhesives allows bonding between PEEK and self-adhesive resin cements. Plasma treatment has no impact on bond to resin cements. CLINICAL SIGNIFICANCE: PEEK reconstructions can be cemented using self-adhesive resin cements combined with pretreatment with MMA-based adhesives. PMID:23504226

Stawarczyk, B; Bähr, N; Beuer, F; Wimmer, T; Eichberger, M; Gernet, W; Jahn, D; Schmidlin, P R

2013-03-17

16

Effects of curing protocols on fluid kinetics and hardness of resin cements.  

PubMed

The effects of polymerization protocols on water sorption/solubility, the diffusion coefficient (D), the flux (J), and the hardness (KH) of two resin cements were evaluated. The materials were manipulated and divided into three groups (n=6) according to the curing protocol: PA=photoactivation (40 s); DP=delayed photoactivation (10 min self-curing plus 40 s photoactivated); CA=chemical activation. After desiccation, the specimens were weighed, stored in water (37ºC), evaluated over 28-days, and hardness recorded. Chemical activation resulted in lower net water uptake, D, and J for RelyX ARC (RX). For Variolink II (VL), CA yielded equivalent D and lower J; however, photoactivation resulted in lower net water uptake. Hardness of VL was less affected by the water storage, irrespective of the polymerization protocol. Considering the water diffusion parameters, VL demonstrated immediate photoactivation dependence; for RX, a chemical activation. Different polymerization protocols affect the fluid kinetics and the hardness of the resin cements tested. PMID:23370868

Svizero, Nádia da Rocha; Silva, Marília Santos; Alonso, Roberta Caroline Bruschi; Rodrigues, Flávia Pires; Hipólito, Vinícius Di; Carvalho, Ricardo Marins; D'Alpino, Paulo Henrique Perlatti

2013-01-01

17

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

18

Solidification of ion exchange resin wastes in hydraulic cement  

SciTech Connect

Work has been conducted to investigate the solidification of ion exchange resin wastes with portland cements. These efforts have been directed toward the development of acceptable formulations for the solidification of ion exchange resin wastes and the characterization of the resultant waste forms. This paper describes formulation development work and defines acceptable formulations in terms of ternary phase compositional diagrams. The effects of cement type, resin type, resin loading, waste/cement ratio and water/cement ratio are described. The leachability of unsolidified and solidified resin waste forms and its relationship to full-scale waste form behavior is discussed. Gamma irradiation was found to improve waste form integrity, apparently as a result of increased resin crosslinking. Modifications to improve waste form integrity are described. 3 tables.

Neilson, R.M. Jr.; Kalb, P.; Fuhrmann, M.; Colombo, P.

1982-01-01

19

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

20

Effect of immediate and delayed light activation on the mechanical properties and degree of conversion in dual-cured resin cements.  

PubMed

We evaluated the effect of activation mode (immediate or delayed light activation vs. no light activation) on diametral tensile strength (DTS), elastic modulus, ultimate tensile strength (UTS), and degree of conversion (DC) in dual-cured resin cements. Three resin cements were evaluated: Enforce, RelyX ARC, and Panavia F. The mixed cements were inserted into circular molds for the DTS test and into dumbbell-shaped molds for the UTS test. Inside the molds, the cements were light-activated either immediately or after 5 min (delayed light activation). If no light activation was performed, the materials were protected from light exposure (control). The DTS and UTS tests were performed until fracture. The elastic modulus was calculated using data from the DTS test, and DC was evaluated 24 h after manipulation using near-infrared spectroscopy. Data for each variable were individually analyzed by two-way ANOVA and the post-hoc Tukey test (? = 0.05). Regarding DTS, activation mode influenced only Panavia Fspecimens, which had the lowest DTS values in the absence of light activation. Activation mode did not influence the elastic modulus or UTS of any resin cement evaluated. Immediate light activation yielded higher DC values as compared with the absence of light activation. PMID:23047037

Faria-e-Silva, André L; Piva, Evandro; Lima, Giana S; Boaro, Letícia C; Braga, Roberto R; Martins, Luis R M

2012-09-01

21

Effect of light energy density on conversion degree and hardness of dual-cured resin cement.  

PubMed

This study evaluated the effect of different light energy densities on conversion degree (CD) and Knoop hardness number (KHN) of RelyX ARC (RLX) resin cement. After manipulation according to the manufacturer's instructions, RLX was inserted into a rubber mold (0.8 mm x 5 mm) and covered with a Mylar strip. The tip of the light-curing unit (LCU) was positioned in contact with the Mylar surface. Quartz-tungsten-halogen (QTH) and light-emitting diode (LED) LCUs with light densities of 10, 20 and 30 J/cm2 were used to light-cure the specimens. After light curing, the specimens were stored dry in lightproof containers at 37 degrees C. After 24 hours, the CD was analyzed by FT-Raman and, after an additional 24-hours, samples were submitted to Knoop hardness testing. The data of the CD (%) and KHN were submitted to two-way ANOVA and the Tukey's test (alpha = 0.05). QTH and LED were effective light curing units. For QTH, there were no differences among the light energy densities for CD or KHN. For LED, there was a significant reduction in CD with the light energy density set at 10 J/cm2. KHN was not influenced by the light-curing unit and by its light energy density. PMID:20166419

Komori, Paula Carolina de Paiva; de Paula, Andréia Bolzan; Martin, Airton Abr?o; Tango, Rubens Nisie; Sinhoreti, Mario Alexandre Coelho; Correr-Sobrinho, Lourenço

22

Fatigue Behavior of the Resinous Cement to Zirconia Bond.  

PubMed

PURPOSE: Resinous cements are widely used for luting zirconia restorations. Adhesive failures have occurred at the cement/zirconia interface, rather than at the cement/dentin interface, suggesting that the cement/zirconia bond may lack durability; however, few comprehensive, comparative evaluations of fatigue effects have been reported. The rate of fatigue-induced loss of bond strength may be a more important predictor of long-term success than a single snapshot of bond strength after an arbitrary number of thermocycles. Previous studies have failed to identify trends by investigating bond strengths at several different numbers of cycles. This may result in invalid conclusions about which cements have superior bond strengths. The purpose of this study was to investigate the effects of artificial aging by thermocycling and resinous cement type on bond strengths to zirconia. MATERIALS AND METHODS: The effect of the number of thermocycles (0, 1, 10, 100, 1000, and 10,000) on the bond strengths of five resinous cements, two of which were used with and without a primer, and an oxygen-inhibiting gel, was studied. Specimens were randomly assigned to thermocycle number/cement-type test groups. Because zirconia has a very low thermal diffusivity, exceptionally long thermocycle dwell times were used. Cylinders of zirconia were bonded end-to-end. One end of each bonded specimen was insulated, specimens were thermocycled and tested in shear, and bond strengths were calculated and analyzed. RESULTS: Two-way ANOVA revealed that the effects of cement type, the number of thermocycles, and their interaction all significantly affected bond strength (p < 0.0001). By 10,000 cycles, most cements had lost at least half of their initial bond strengths, and two cements effectively recorded zero bond strengths. Failure modes were cement specific, but adhesive modes predominated. Fatigue resistance of two cements was greatly improved by use of a primer and an oxygen-inhibiting gel, as recommended by their respective manufacturers. CONCLUSIONS: Both the type of resin cement and the number of thermocycles influenced bond strength. Fatigue through thermocycling affected different cement types in different ways. Some materials displayed more rapid loss of bond strength than others. Cements differed in their failure modes. PMID:23724930

Seto, Kevin B; McLaren, Edward A; Caputo, Angelo A; White, Shane N

2013-05-31

23

Micro-tensile bond testing of resin cements to dentin and an indirect resin composite  

Microsoft Academic Search

Objectives: Micro-tensile bond strength (?TBS) evaluation and fractographic analysis were used to compare four resin cement systems (AC: All-Bond 2\\/Choice; RX: Single Bond\\/RelyX ARC; SB: Super-Bond C&B; and PF: Panavia F) in indirect composite\\/dentin adhesive joints.Methods: Flat dentin surfaces were created on extracted human third molars. The resin cements were used according to the manufacturers' instructions for bonding silanized composite

Yiu-Fai Mak; Shirley C. N Lai; Gary S. P Cheung; Alex W. K Chan; Franklin R Tay; David H Pashley

2002-01-01

24

Evaluation of TEGDMA leaching from four resin cements by HPLC  

PubMed Central

Objective The aim of this study was to evaluate the elution of TEGDMA from dual cured resin cements, used for bonding of ceramic restoration by high performance liquid chromatography (HPLC). Methods: Forty freshly extracted caries and restoration free molar teeth used in this study. Standardized Class I preparations were prepared in all teeth. Ceramic inlays were cemented with one of the dual cured resin cements (Variolink II, Rely X ARC, Rely X Unicem and Resilute). After cementation, specimens were stored in 75% ethanol solution. HPLC was used to analyze the amounts of TEGDMA in different time intervals. Two-way ANOVA and Tukey HSD tests were used to evaluate the results (P<.05). Results: The amount of TEGDMA eluted from Resilute was the highest and the amount of TEG-DMA eluted from Rely X Unicem was the lowest (P<.05). The total amount of monomers was the highest after 21 days (P<.05). Conclusion: In the case of resin cements, elution of TEGDMA was the highest in Resilute and lowest in Rely X Unicem. The amount of TEGDMA eluted from resin cements was influenced by the time.

Altintas, Subutay Han; Usumez, Aslihan

2012-01-01

25

Effect of Resin Coating and Chlorhexidine on Microleakage of Two Resin Cements after Storage  

PubMed Central

Objective: Evaluating the effect of resin coating and chlorhexidine on microleakage of two resin cements after water storage. Materials and Methods: Standardized class V cavities were prepared on facial and lingual surfaces of one hundred twenty intact human molars with gingival margins placed 1 mm below the cemento-enamel junction. Indirect composite inlays were fabricated and the specimens were randomly assigned into 6 groups. In Groups 1 to 4, inlays were cemented with Panavia F2.0 cement. G1: according to the manufacturer’s instruction. G2: with light cured resin on the ED primer. G3: chlorhexidine application before priming. G4: with chlorhexidine application before priming and light cured resin on primer. G5: inlays were cemented with Nexus 2 resin cement. G6: chlorhexidine application after etching. Each group was divided into two subgroups based on the 24-hour and 6-month water storage time. After preparation for microleakage test, the teeth were sectioned and evaluated at both margins under a 20× stereomicroscope. Dye penetration was scored using 0–3 criteria. The data was analyzed using Kruskal-Wallis and complementary Dunn tests. Results: There was significantly less leakage in G2 and G4 than the Panavia F2.0 control group at gingival margins after 6 months (P<0.05). There was no significant differences in leakage between G1 and G3 at both margins after 24 hours and 6 months storage. After 6 months, G6 revealed significantly less leakage than G5 at gingival margins (P=0.033). In general, gingival margins showed more leakage than occlusal margins. Conclusion: Additionally, resin coating in self-etch (Panavia F2.0) and chlorhexidine application in etch-rinse (Nexus) resin cement reduced microleakage at gingival margins after storage.

Shafie, F.; Doozandeh, M.; Alavi, A.

2010-01-01

26

Progress in Solidification of Radioactive Waste Resins Using Specific Cement  

SciTech Connect

A kind of special cement (Named as ASC) was used in radioactive spent resins solidification in China. A prescription of X ASC cement + 0.5 X waste resins (50% water hold) + 0.35 X water was obtained first. In order to control the temperature rise caused by hydration of cement in 200 L solidification matrix, various supplementary materials were tried. Based on compressive strength tests and center temperature rise, super powered zeolite was selected. In addition, more resins were added to reduce the center temperature rise. A superior combination was obtained as ASC 35 wt.%, zeolite 7 wt.% to mix 42 wt.% of resins (50% water hold) with 16 wt.% of water. The microstructures of hydrated OPC, ASC and ASC with different zeolite addition were compared by means of Scanning Electron Microscopy (SEM). From the SEM pictures, the structures of the needles or spines can be seen in ASC matrices and the needles structure of ASC change into flake structure gradually with more zeolite added. The simulated leaching tests showed that inclusion of zeolite in ASC reduced the leaching rates of radionuclides significantly. From 200 L matrix test, the centre temperature curve was measured, and the highest temperature was lower than 90 deg. C. No thermal cracks were found in the final solidified products. (authors)

Li, J.F.; Ye, Y.C.; Wang, J.L. [Institute of Nuclear and New Energy Technology - INET, Tsinghua University, Beijing 100084 (China)

2006-07-01

27

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

28

Adhesive permeability affects coupling of resin cements that utilise self-etching primers to dentine  

Microsoft Academic Search

Objectives. To examine the effects of an experimental bonding technique that reduces the permeability of the adhesive layer on the coupling of resin cements to dentine.Methods. Extracted human third molars had their mid to deep dentin surface exposed flat by transversally sectioning the crowns. Resin composite overlays were constructed and cemented to the surfaces using either Panavia F (Kuraray) or

R. M. Carvalho; T. A. Pegoraro; F. R. Tay; L. F. Pegoraro; N. R. F. A. Silva; D. H. Pashley

2004-01-01

29

Color agreement between nanofluorapatite ceramic discs associated with try-in pastes and with resin cements.  

PubMed

The aim of this study was to evaluate the in vitro color agreement between nanofluorapatite ceramic discs (e.max Ceram / Ivoclar Vivadent / A2) associated with try-in pastes and those bonded with resin cements (Vitique / DMG/ try-in shade A2½ and cement shade A2½, Variolink II / Ivoclar Vivadent / try-in shade A1 and cement shade A1, and Choice 2 / Bisco / try-in shade A2 and cement shade A2), and to evaluate the shade stability of the discs bonded with resin cements. The shades of composite resin discs (Lliss / FGM / A2) and nanofluorapatite ceramic discs with try-in pastes or cements were evaluated according to the Vita Classical shade guide by a digital spectrophotometer (Micro EspectroShade, MHT) immediately after placing the try-in pastes or resin cements between composite resin discs and ceramic discs. Other evaluations were performed at 2, 5, and 6 day intervals after cementation with the resin cements. All ceramic discs that received try-in pastes presented an A2 shade. There was no statistical difference in the shade of the ceramic specimens fixed with different cements at the different intervals, as evaluated by the Friedman test (p > 0.05). Two try-in pastes presented shade compatibility with those recommended by the manufacturers. There was no similarity of shades between the ceramic discs with try-in pastes and those with the respective resin cements. Shade stability was observed in ceramic discs with resin cements within the intervals evaluated. PMID:23184164

Rigoni, Paulo; Amaral, Flávia Lucisano Botelho do; França, Fabiana Mantovani Gomes; Basting, Roberta Tarkany

30

Influence of cement thickness on resin-zirconia microtensile bond strength  

PubMed Central

PURPOSE The aim of this study was to evaluate the influence of resin cement thickness on the microtensile bond strength between zirconium-oxide ceramic and resin cement. MATERIALS AND METHODS Thirty-two freshly extracted molars were transversely sectioned at the deep dentin level and bonded to air-abraded zirconium oxide ceramic disks. The specimens were divided into 8 groups based on the experimental conditions (cement type: Rely X UniCem or Panavia F 2.0, cement thickness: 40 or 160 µm, storage: thermocycled or not). They were cut into microbeams and stored in 37? distilled water for 24 h. Microbeams of non-thermocycled specimens were submitted to a microtensile test, whereas those of thermocycled groups were thermally cycled for 18,000 times immediately before the microtensile test. Three-way ANOVA and Sheffe's post hoc tests were used for statistical analysis (?=95%). RESULTS All failures occurred at the resin-zirconia interface. Thermocycled groups showed lower microtensile bond strength than non-thermocycled groups (P<.001). Differences in cement thickness did not influence the resin-zirconia microtensile bond strength given the same resin cement or storage conditions (P>.05). The number of adhesive failures increased after thermocycling in all experimental conditions. No cohesive failure was observed in any experimental group. CONCLUSION When resin cements of adhesive monomers are applied over air-abraded zirconia restorations, the degree of fit does not influence the resin-zirconia microtensile bond strength.

Lee, Tae-Hoon; Ahn, Jin-Soo; Shim, June-Sung; Han, Chong-Hyun

2011-01-01

31

Advances in cement solidification technology for waste radioactive ion exchange resins: a review.  

PubMed

Treatment and disposal of waste radioactive ion exchange resins is one of the most urgent problems for nuclear industries in China. Cement solidification technology has many advantages, such as requiring simple equipment, easy scaling-up, low working temperature, no trouble of gas cleaning and low cost. It is a suitable technology for treatment of waste radioactive resins, and has been widely used. The new developments and theoretical basis of cement solidification of radioactive resins were introduced in this paper. The cement solidification technology suitable for China and the questions needed to solve were also discussed. PMID:16388899

Li, Junfeng; Wang, Jianlong

2006-01-04

32

The root canal bonding of chemical-cured total-etch resin cements.  

PubMed

Discovering a durable restorative method to reconstruct and reinforce pulpless teeth is a vital key to help prevent root fractures. Complete and firm adhesion of resin cement in root canal dentin using a post is critical to achieve it. The null hypothesis in the present study was that the bond strength of dual-cured and chemical-cured adhesive resin cements to root canal dentin is not affected by their vertical locations in the root canal. In the experiments, extracted human incisors restored with fiber-reinforced posts and adhesive resin cements were subjected to microtensile bond strength testing. Then, the failure modes and the dentin-bonding interfaces were observed. Self-etch and self-adhesive dual-cured resin cements showed frequent pretesting failure despite using a silane coupling agent. Chemical-cured total-etch adhesive material showed stable bonding performances throughout the entire post space and thus has an advantage in post-core restorations. PMID:18436039

Hayashi, Mikako; Okamura, Kenji; Wu, Hongxia; Takahashi, Yutaka; Koytchev, Evgeni V; Imazato, Satoshi; Ebisu, Shigeyuki

2008-03-24

33

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

34

Tensile bond strength of a composite resin cement for bonded prosthesis to various dental alloys.  

PubMed

The development of composite resin cements that chemically bond to dental alloys has improved the construction of resin-bonded prostheses. Composite resins can be selected for various situations, but specific clinical situations may require different alloys. This study evaluated the ability of a composite resin cement to bond to various dental alloys of different compositions. Ten pairs of disks for each alloy (two NiCr, two NiCrBe, one CuAl, one gold type IV, and one gold for metal ceramic) were bonded to a composite resin cement after air abrasion was performed with aluminum oxide. The disks were then rinsed in tap water and were ultrasonically cleaned in distilled water for 2 minutes. The tensile tests exhibited greater values for alloys ultrasonically cleaned, and the best results were recorded by NiCr and NiCrBe alloys. PMID:7473275

Rubo, J H; Pegoraro, L F

1995-09-01

35

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

36

Treatment of a Vertical Root Fracture Using Dual-Curing Resin Cement: A Case Report  

PubMed Central

Introduction. Vertical root fracture (VRF) is one of the most frustrating complications of root canal treatment. The prognosis of the root with VRF is poor therefore tooth extraction and root amputation are usually the only treatment options. However, bonding of the fracture line with adhesive resin cement during the intentional replantation procedure was recently suggested as an alternative to tooth extraction. Methods. A vertically fractured left maxillary incisor was carefully extracted, fracture line was treated with adhesive resin cement, a retrograde cavity was produced and filled with calcium-enriched mixture (CEM) cement, and tooth was replanted. Results. After 12 months the tooth was asymptomatic. The size of periapical radiolucency was noticeably reduced and there was no clinical sign of ankylosis. Conclusion. Using adhesive resin cement to bond the fracture lines extraorally in roots with VRF and intentional replantation of the reconstructed teeth could be considered as an alternative to tooth extraction, especially for anterior teeth.

Moradi Majd, Nima; Akhtari, Farshid; Araghi, Solmaz; Homayouni, Hamed

2012-01-01

37

Effect of light source and solvent on the sorption and solubility of two dual-cured cements photocured through ceramic.  

PubMed

The purpose of this study was to verify the polymerization efficiency of two curing units through a ceramic barrier. Forty specimens apiece of two resin luting cements (AllCem and RelyX U100) were made in a stainless steel mold. The experimental group was photocured through a ceramic barrier, while the control group was photocured without a barrier. The specimens were stored in deionized water or 75% ethanol for 28 days and submitted to tests of sorption and solubility (ISO 4049:2000). Values obtained were subjected to ANOVA and Tukey multiple comparison tests (P < 0.05). RelyX U100 suffered more sorption and solubility than AllCem. The light sources did not influence sorption and solubility values, except for the specimens of RelyX U100 that were photocured with an LED unit through ceramic and stored in ethanol; these specimens demonstrated higher values than those photocured using a halogen lamp. PMID:22313990

Lopes, Lawrence Gonzaga; Magalhaes, Ana Paula Rodrigues; Brandao, Natasha Amorim; Carvalho, Andreia Assis; Moreira, Francine do Couto Lima; de Souza, Joao Batista

38

Cementation of ILW ion exchange resins: Impact of sulfate ions released by radiolysis on hydrated matrix  

NASA Astrophysics Data System (ADS)

Some of the ion exchange resins used during treatment of spent nuclear fuels are intermediate level radioactive wastes which may be damaged by radiolysis process, releasing sulfate ions directly into the cement-based encapsulating material. This work consists in an experimental study of the resulting sulfate attack on the properties of the hydrated matrix: dimensional stability, mineralogy and microstructure of the samples, as well as variations in the chemical composition of the curing solution, were studied during six months. Three sites of delayed ettringite formation were detected: into the cement matrix near the surface exposed to solution, localized in the interfacial transition zone between cement matrix and resins, or progressively replacing the portlandite that initially fulfilled the cracks of anionic resins. During the experiment period, the ettringite precipitation and the expansion detected were moderate, and did not lead to cracking. The material involved was considered as having a good resistance to sulfate attack.

Frizon, F.; Cau-Dit-Coumes, C.

2006-12-01

39

The use of reinforced composite resin cement as compensation for reduced post length  

Microsoft Academic Search

Statement of Problem. Cements that yield high retentive values are believed to allow use of shorter posts. Purpose. This study investigated the use of reinforced composite resin cement as compensation for reduced dowel length. Material and Methods. The retention values of stainless steel posts (parallel-sided ParaPost and tapered Dentatus in 5-, 8-, and 10-mm lengths) luted with Flexi-Flow titanium-reinforced composite

Joseph Nissan; Yevnin Dmitry; David Assif

2001-01-01

40

A medicated polycarboxylate cement to prevent complications in composite resin therapy  

SciTech Connect

Preparative treatment is the preferred method to protect the dentin and pulp from complications in composite resin therapy. This study investigated the in vivo effects of the polycarboxylate cement containing zinc fluoride and tannic acid in composite resin restorations. Scanning electron micrographs established that the composite resin failed to contact the axial wall. The gaps varied from 10 to 60 microns. However, this polycarboxylate cement was shown to provide excellent adaptation to dentin when used as a base and its chemical adhesion allowed it to make close contact with the unetched dentin. The newly developed electron probe x-ray microanalyzer revealed that the in vivo penetration of fluoride and zinc occurred through the dentinal tubules. When this polycarboxylate cement was used, the orifices of dentinal tubules were partially occluded, possibly with the smear layer fixed by tannic acid. In addition, by releasing the components, this polycarboxylate cement adds acid resistance to dentin and increases the resistance of dentin collagen to proteolytic enzymes. As such this polycarboxylate cement offers advantages as a base to composite resin therapy.

Okamoto, Y.; Shintani, H.; Yamaki, M. (Hiroshima Univ., School of Dentistry (Japan))

1990-01-01

41

Bonding All-Ceramic Restorations with Two Resins Cement Techniques: A Clinical Report of Three-Year Follow-Up  

PubMed Central

Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate. This article presents three-year clinical results of a 41 years old female patient B.H.C complaining about her unattractive smile. Two all-ceramic crowns and two laminates veneers were placed in the maxillary incisors and cemented with a self-adhesive resin luting cement and conventional resin luting cement, respectively. After a three-year follow-up, the restorations and cement/teeth interface were clinically perfect with no chipping, fractures or discoloration. Proper use of different resin luting cements shows clinical appropriate behavior after a three-year follow-up. Self-adhesive resin luting cement may be used for cementing all-ceramic crowns with high predictability of success, mainly if there is a large dentin surface available for bonding and no enamel at the finish line. Otherwise, conventional resin luting agent should be used for achieving an adequate bonding strength to enamel.

Anchieta, Rodolfo Bruniera; Rocha, Eduardo Passos; de Almeida, Erika Oliveira; Junior, Amilcar Chagas Freitas; Martini, Ana Paula

2011-01-01

42

Bond strength of resin cement to zirconia ceramic with different surface treatments.  

PubMed

Zirconia-based ceramics offer strong restorations in dentistry, but the adhesive bond strength of resin cements to such ceramics is not optimal. This study evaluated the influence of surface treatments on the bond strength of resin cement to yttrium-stabilized tetragonal zirconia (Y-TZP) ceramic. Seventy-five plates of Y-TZP ceramic were randomly assigned to five groups (n = 15) according to the surface treatments [airborne particle abrasion, neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation (Fidelis Plus 3, Fotona; 2 W, 200 mJ, 10 Hz, with two different pulse durations 180 or 320 ?s), glaze applied, and then 9.5 % hydrofluoric acid gel conditioned, control]. One specimen from each group was randomly selected, and specimens were evaluated with x-ray diffraction and SEM analysis. The resin cement (Clearfil Esthetic Cement, Kuraray) was adhered onto the zirconia surfaces with its corresponding adhesive components. Shear bond strength of each sample was measured using a universal testing machine at a crosshead speed of 1 mm/min. Bond strengths were analyzed through one-way ANOVA/Tukey tests. Surface treatments significantly modified the topography of the Y-TZP ceramic. The Nd:YAG laser-irradiated specimens resulted in both increased surface roughness and bond strength of the resin cement. The highest surface roughness and bond strength values were achieved with short pulse duration. Nd:YAG laser irradiation increased both surface roughness of Y-TZP surfaces and bond strength of resin cement to the zirconia surface. PMID:22718473

Usumez, Asl?han; Hamdemirci, Nermin; Koroglu, Bilge Yuksel; Simsek, Irfan; Parlar, Ozge; Sari, Tugrul

2012-06-21

43

Effects of surface treatments, thermocycling, and cyclic loading on the bond strength of a resin cement bonded to a lithium disilicate glass ceramic.  

PubMed

SUMMARY Objectives : The aim of this present study was to investigate the effect of two surface treatments, fatigue and thermocycling, on the microtensile bond strength of a newly introduced lithium disilicate glass ceramic (IPS e.max Press, Ivoclar Vivadent) and a dual-cured resin cement. Methods : A total of 18 ceramic blocks (10 mm long × 7 mm wide × 3.0 mm thick) were fabricated and divided into six groups (n=3): groups 1, 2, and 3-air particle abraded for five seconds with 50-?m aluminum oxide particles; groups 4, 5, and 6-acid etched with 10% hydrofluoric acid for 20 seconds. A silane coupling agent was applied onto all specimens and allowed to dry for five seconds, and the ceramic blocks were bonded to a block of composite Tetric N-Ceram (Ivoclar Vivadent) with RelyX ARC (3M ESPE) resin cement and placed under a 500-g static load for two minutes. The cement excess was removed with a disposable microbrush, and four periods of light activation for 40 seconds each were performed at right angles using an LED curing unit (UltraLume LED 5, Ultradent) with a final 40 second light exposure from the top surface. All of the specimens were stored in distilled water at 37°C for 24 hours. Groups 2 and 5 were submitted to 3,000 thermal cycles between 5°C and 55°C, and groups 3 and 6 were submitted to a fatigue test of 100,000 cycles at 2 Hz. Specimens were sectioned perpendicular to the bonding area to obtain beams with a cross-sectional area of 1 mm(2) (30 beams per group) and submitted to a microtensile bond strength test in a testing machine (EZ Test) at a crosshead speed of 0.5 mm/min. Data were submitted to analysis of variance and Tukey post hoc test (p?0.05). Results : The microtensile bond strength values (MPa) were 26.9 ± 6.9, 22.2 ± 7.8, and 21.2 ± 9.1 for groups 1-3 and 35.0 ± 9.6, 24.3 ± 8.9, and 23.9 ± 6.3 for groups 4-6. For the control group, fatigue testing and thermocycling produced a predominance of adhesive failures. Fatigue and thermocycling significantly decreased the microtensile bond strength for both ceramic surface treatments when compared with the control groups. Etching with 10% hydrofluoric acid significantly increased the microtensile bond strength for the control group. PMID:22856682

Guarda, G B; Correr, A B; Gonçalves, L S; Costa, A R; Borges, G A; Sinhoreti, M A C; Correr-Sobrinho, L

2012-08-03

44

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

45

Effect of Self-adhesive Resin Cement and Tribochemical Treatment on Bond Strength to Zirconia  

PubMed Central

Aim To evaluate the interactive effects of different self-adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconia blocks were evaluated: Maxcem (MA), Smartcem (SM), Rely X Unicem Aplicap (UN), Breeze (BR), Biscem (BI), Set (SE), and Clearfil SA luting (CL). The specimens were grouped according to conditioning as follows: Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 µm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment - silica coating + silanization. Specimens were stored in distilled water at 37°C for 24 hours before testing shear bond strength. Results Silica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, BI, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP-containing self-adhesive resin cement CL had the highest bond strengths to zirconia. Conclusion Applying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.

Lin, Jie; Shinya, Akikazu; Gomi, Harunori; Shinya, Akiyoshi

2010-01-01

46

Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste  

NASA Astrophysics Data System (ADS)

There are no works related to the corrosion of drums containing radioactive waste.Chloride induces high corrosion rate and after 1 year it drops abruptly.Decrease in the corrosion rate is due to the lack of water to sustain the process.Cementated ion-exchange resins do not pose risks of corrosion of the steel drums.

Duffó, G. S.; Farina, S. B.; Schulz, F. M.

2013-07-01

47

Radiopacity of different resin-based and conventional luting cements compared to human and bovine teeth.  

PubMed

This study evaluated the radiopacity of different resin-based luting materials and compared the results to human and bovine dental hard tissues. Disc specimens (N=130, n=10 per group) (diameter: 6 mm, thickness: 1 mm) were prepared from 10 resin-based and 3 conventional luting cements. Human canine dentin (n=10), bovine enamel (n=10), bovine dentin (n=10) and Aluminium (Al) step wedge were used as references. The optical density values of each material were measured from radiographic images using a transmission densitometer. Al step wedge thickness and optical density values were plotted and equivalent Al thickness values were determined for radiopacity measurements of each material. The radiopacity values of conventional cements and two resin luting materials (Rely X Unicem and Variolink II), were significantly higher than that of bovine enamel that could be preferred for restorations cemented on enamel. Since all examined resin-based luting materials showed radiopacity values equivalent to or greater than that of human and bovine dentin, they could be considered suitable for the restorations cemented on dentin. PMID:22277608

Pekkan, Gürel; Ozcan, Mutlu

2012-01-21

48

Bond strength of two resin cements to titanium after different surface conditioning methods.  

PubMed

This study evaluated the bond strength of two resin cements (Panavia F and Super Bond) to titanium after various surface conditioning techniques. The cements were applied using polyethylene tubes. After thermocycling, the specimens were tested in a universal testing machine for shear bond strength. Panavia F demonstrated significantly higher bond strength values than Super Bond. Of the conditioning techniques, Al2O3+Silane+Sinfony and Silano Pen+AP demonstrated significantly lower bond strength values than Al2O3+Cesead II Opaque Primer and 110 µm SiOx+Silane. The combination of Panavia and 110 µm SiOx+Silane, Al2O3+AP, or Al2O3+Cesead II, and the combination of Super Bond and 110 µm SiOx+Silane or Al2O3+Cesead II, can be recommended for improving the bond strength of resin cement to titanium. PMID:22313994

Ozcan, Mutlu; Valandro, Luiz Felipe

49

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

50

Influence of Curing Light Attenuation Caused by Aesthetic Indirect Restorative Materials on Resin Cement Polymerization  

PubMed Central

Objectives: To verify the effect of interposing different indirect restorative materials on degree of conversion (DC), hardness, and flexural strength of a dual-cure resin cement. Methods: Discs (2 mm-thick, n=5) of four indirect restorative materials were manufactured: a layered glass-ceramic (GC); a heat-pressed lithium disilicate-based glass-ceramic veneered with the layered glass-ceramic (LD); a micro-hybrid (MH); and a micro-filled (MF) indirect composite resin. The light transmittance of these materials was determined using a double-beam spectrophotometer with an integrating sphere. Bar-shaped specimens of a dual-cure resin cement (Nexus 2/SDS Kerr), with (dual-cure mode) and without the catalyst paste (light-cure mode), were photoactivated through the discs using either a quartz-tungsten-halogen (QTH) or a light-emitting diode (LED) unit. As a control, specimens were photoactivated without the interposed discs. Specimens were stored at 37ºC for 24h before being submitted to FT-Raman spectrometry (n=3), Knoop microhardness (n=6) and three-point bending (n=6) tests. Data were analyzed by ANOVA/Tukey’s test (?=0.05). Results: MH presented the highest transmittance. The DC was lower in light-cure mode than in dual-cure mode. All restorative materials reduced the cement microhardness in light-cure mode. GC and LD with QTH and GC with LED decreased the strength of the cement for both activation modes compared to the controls. Curing units did not affect DC or microhardness, except when the dual-cure cement was photoactivated through LD (LED>QTH). Flexural strength was higher with QTH compared to LED. Conclusions: Differences in transmittance among the restorative materials significantly influenced cement DC and flexural strength, regardless of the activation mode, as well as the microhardness of the resin cement tested in light-cure mode. Microhardness was not impaired by the interposed materials when the resin cement was used in dual-cure mode.

Pick, Barbara; Gonzaga, Carla Castiglia; Junior, Washington Steagall; Kawano, Yoshio; Braga, Roberto Ruggiero; Cardoso, Paulo Eduardo Capel

2010-01-01

51

Solidification in cement of ion-exchange resins from LOMI (Low Oxidation State Metal Ion) decontamination  

SciTech Connect

Chemical decontamination of operating nuclear power plants is performed to remove radioactive metal oxides from pipes and equipment thereby reducing the radiation exposure to personnel performing inspection and maintenance. The LOMI (Low Oxidation State Metal Ion) process is widely used to perform this decontamination. At the end of the decontamination operations, the chemicals remaining in solution are removed by ion exchange resins. The resins are subsequently solidified in metal liners using cement, transported and buried at an approved burial site. The work covered by this report was undertaken because of an incomplete solidification of the ion exchange resins. The details of the decontamination operations have been described. At the time the problem arose, a preliminary investigation led to the conclusion that the unsolidified resin resulted from inadequate mixing caused by the formation of hydrated gel. The purpose of this project was to develop an understanding of the variables affecting the formation of the gel and to devise methods to avoid its formation. Additionally, safe limits would be defined that would assure the complete solidification in cement of ion exchange resins used in LOMI chemical decontaminations. 5 refs., 3 figs., 6 tabs.

Not Available

1990-08-01

52

Effect of flexural strength of orthodontic resin cement on bond strength of metal brackets to enamel surfaces.  

PubMed

Three types of experimental resin cements with different curing systems, dual, light, and chemical, were designed. The relationship between the flexural strengths of the three experimental and five commercial (Beauty Ortho Bond, Transbond™ XT, Light Cure Bond, Kurasper® F, and Super Bond) orthodontic resin cements on the tensile bond strength (TBS) and shear bond strength (SBS) of metal brackets to enamel was determined. Seven specimen bars of each resin were prepared for measuring the flexural strengths of the resins. Bonded specimens of each resin were prepared, seven for measuring TBS and seven SBS for after bonding of a metal bracket to a maxillary central human labial anterior tooth using experimental and commercial resin cements. The results were analysed by one-way analysis of variance and Scheffé's multiple comparison tests. The level of statistical significance was set at 0.05. Increases in the flexural strength of the resin cements were related to increases in the TBS and SBS of the metal bracket. While the light-curing cements exhibited a strong linear correlation between flexural strengths and TBS or SBS, the dual- and chemical-curing cements exhibited a different flexural strength effect on both TBS and SBS. This was a result of the adhesive layer under the metal bracket, which could be chemically cured, in contrast to the light-curing cement. To control setting time and to obtain higher initial TBS and SBS by polymerizing the resin cement under the bracket, a dual-curing system, that combines both light- and chemical-curing systems, is essential. PMID:20937669

Li, Jun

2010-10-11

53

Effect of etch-and-rinse and self-etching adhesive systems on hardness uniformity of resin cements after glass fiber post cementation  

PubMed Central

Objective To evaluate the effects of etch-and-rinse and self-etching adhesive systems on Vickers hardness (VHN) uniformity of dual-cured resin cements after fiber post cementation. Methods: Fifty glass fiber posts were cemented into bovine roots using the following cementing systems: Prime&Bond 2.1 Dual Cure and Enforce with light-activation (PBDC-LCEN); Prime&Bond 2.1 and Enforce with light-activation (PB-CLEN); Prime&Bond 2.1 Dual Cure and Enforce without light exposure (PBDC-SCEN); ED Primer and Panavia 21 (ED-SCPN); and Clearfil SE Bond and Panavia 21 (CF-SCPN). The roots were stored in distilled water for 72 h and transversely sectioned into thirds (coronal, medium, and apical). The VHN values of the resin cement layers were measured close to the post and to the dentin wall on the transversely sectioned flat surfaces. The results were analyzed by three-way repeated measures analysis of variance (ANOVA) and Tukey’s post-hoc test (pre-set alpha of 5%). Results: Most resin cements presented higher VHN values near the post than near the dentin wall. The ED-SCPN group showed the highest VHN values regardless of the root third, while the self-cured group PBDC-SCEN exhibited the lowest values. The resin cements from the light-activated groups PBDC-LCEN and PB-LCEN showed lower VHN values at the apical third than at the coronal third. The VHN values were not influenced by the root third in self-cured groups PBDC-SCEN, ED-SCPN, and ED-SCPN. Conclusion: Depending on the product, bonding agents might promote changes in hardness uniformity of resin cements after post cementation.

Grande da Cruz, Fernanda Zander; Grande, Christiana Zander; Roderjan, Douglas Augusto; Galvao Arrais, Cesar Augusto; Buhrer Samra, Adriana Postiglione; Calixto, Abraham Lincoln

2012-01-01

54

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

55

Pilot evaluation of resin composite cement adhesion to zirconia using a novel silane system  

Microsoft Academic Search

Objective. In this study, we evaluated the effect of two silane coupling agents and their blends with a cross-linker silane on the bond strength of a dimethacrylate-based resin composite cement to surface-conditioned zirconia. Material and Methods. A total of 40 planar zirconia specimens were used for 8 test groups. After alumina particle abrasion, followed by tribochemical silica-coating, the specimens were

JUKKA P. MATINLINNA; LIPPO V. J. LASSILA; PEKKA K. VALLITTU

2007-01-01

56

[Microleakage pattern around posterior composite resin restorations, combined with a ceramometallic cement (sandwich technique)].  

PubMed

The purpose of this in vitro investigation was to examine the degree of microleakage in class II, MOD, posterior composite resin restorations, in the distal wall of which a layer of 1,5 mm of ceramometallic cement was condensed. Conventional MOD cavities were prepared using 330 and 56 tungsten carbide burs in 20 premolars extracted for orthodontic reasons. In the first group (10 specimens) the gingival floor was located in the enamel, above the cementoenamel junction and in the second group the gingival floor was located below the CEJ. In the mesial box, cervically, a layer of 1,5 mm of ceramometallic cement (Ketac Silver) was condensed and etched with orthophosphoric acid 37%, the cavity was filled with posterior composite resin (Heliomolar, Vivadent) and 24 hours later the specimens were polished using Sof-Lex discs and thermocycled between 4 degrees C and 60 degrees C for 50 cycles of 2 minutes each. The specimens were immersed for 2 hours in 2% basic fuchsin solution, washed, cleaned with acetate solution and split in two halves longitudinally in a mesiodistal direction, using a hard tissue microtome. From the detection of the degree of dye penetration we conclude that: a) In the cervical walls located in cementum, where cermet cement was condensed, minimal dye penetration was detected b) In the opposite side, where the composite resin existed on dentin-cementum, the dye penetration is more severe c) Dye penetration in cavities located in the enamel, is moderate in the areas where cermet cement existed d) No dye was detected in the interface between cermet cement and posterior composite, in most specimens. PMID:2130314

Tzoutzas, J; Mountouris, G; Vougiouklakis, G

1990-02-01

57

Push-out bond strength of a fiber post system with two resin cements  

PubMed Central

Introduction: Debonding is a common cause of failure encountered with fiber-reinforced composite (FRC) posts, and usually occurs along the post space-dentin adhesive interface. The aim of this in vitro study is to evaluate the regional push-out bond strength of a fiber-reinforced post system, using two resin cements. Materials and Methods: In this in vitro study 20 maxillary central incisors were decoronated and the roots were endodontically treated. Following post space preparation, the roots were divided into two groups of 10 specimens each. Fiber-reinforced composite posts were cemented with two resin cement systems: (a) Self-etch system (Panavia F2.0/ED-primer II) and (b) conventional system (Variolink II/Excite DSC). Three slices of each root, with a thickness of 3 mm, were prepared. The push-out test was performed with a universal testing machine at a crosshead speed of 1 mm/minute, and bond strength values were calculated. The data were analyzed with a two-way Analysis of variance (ANOVA) and Scheffe tests (?=.05). Results: There were no significant differences between the mean push-out bond strengths of two experimental groups (Panavia F: 12.59±5.44, Variolink II: 12.49±4.52 MPa) (P=0.920), but there were significant differences between the mean push out bond strengths of the root dentin regions (P<0.001). Conclusion: Under the conditions of this study, there was no significant difference between the mean push out bond strength of self-etching and the conventional resin cement systems. The coronal region of the root dentin showed a significantly higher bond strength than the apical region.

Mosharraf, Ramin; Haerian, Alireza

2011-01-01

58

The leachability of decontamination ion-exchange resins solidified in cement at operating nuclear power plants  

SciTech Connect

Data are presented on the release of radionuclides, stable metals, and organic reagents from decontamination ion-exchange resin wastes solidified in Portland cement. Both solidified and unsolidified decontamination resin waste samples were collected from five commercial light water reactors following chemical decontaminations of primary coolant systems. The decontaminations were performed using the Can-Decon, AP/Citrox, Dow NS-1, and LOMI processes. Samples of unsolidified decontamination resin waste were analyzed for concentrations of 10 CFR Part 61 radionuclides, selected transition metals, and organic chelating and complexing agents. The organic acids included oxalic acid, citric acid, formic acid, picolinic acid, ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DPTA). Seven solidified resin waste samples were leached in deionized water following the ANS 16.1 leach-test procedure. Releases rates and leachability indexes of radionuclides, transition metals, and organic acids were determined. Analytical methods are described which were used to measure organic acids in resin wastes and in leachate solutions generated during leach-testing of waste form samples. Gas-liquid and ion chromatography methods were developed which allowed detection of organic acids in the tenths-of-a-ppM range. 59 refs., 65 figs., 55 tabs.

McIsaac, C.V.; Mandler, J.W.

1989-03-01

59

Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin.  

PubMed

We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin (1 mm below the dentine-enamel junction), deep dentin (1 mm above the highest pulp horn) and cervical dentin (0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction). Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm(2) in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mm/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin (P < 0.001). Micro-tensile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions (P < 0.001). Immediate micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements (P < 0.001). It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions. PMID:23554806

Ali, Abdelraheem Mohamed; Hamouda, Ibrahim Mohamed; Ghazy, Mohamed Hamed; Abo-Madina, Manal Mohamed

2012-12-06

60

Effect of curing mode on the micro-mechanical properties of dual-cured self-adhesive resin cements.  

PubMed

Light supplying to luting resin cements is impeded in several clinical situations, causing us to question whether materials can properly be cured to achieve adequately (or adequate) mechanical properties. The aim of this study was therefore to analyse the effect of light on the micro-mechanical properties of eight popular dual-cured self-adhesive resin cements by comparing them with two conventional, also dual-cured, resin cements. Four different curing procedures were applied: auto-polymerisation (dark curing) and light curing (LED unit, Freelight 2, 20 s) by applying the unit directly on the samples' surface, at a distance of 5 and 10 mm. Twenty minutes after curing, the samples were stored for 1 week at 37°C in a water-saturated atmosphere. The micro-mechanical properties-Vickers hardness, modulus of elasticity, creep and elastic/plastic deformation-were measured. Data were analysed with multivariate ANOVA followed by Tukey's test and partial eta-squared statistics (p?cement-conventional or self-adhesive-was generally low. The influence of light on the polymerisation process was material dependent, with four different behaviour patterns to be distinguished. As a material category, significantly higher micro-mechanical properties were measured for the conventional compared to the self-adhesive resin cements, although this difference was low. Within the self-adhesive resin cements group, the variation in micro-mechanical properties was high. The selection of suitable resin cements should be done by considering, besides its adhesive properties, its micro-mechanical properties and curing behaviour also. PMID:21350865

Ilie, Nicoleta; Simon, Alexander

2011-02-25

61

In-vitro evaluation of an experimental method for bonding of orthodontic brackets with self-adhesive resin cements  

PubMed Central

Background Self-adhesive resin cements do not require the surface treatment of teeth and are said to release fluoride, which makes them suitable candidates for bonding of orthodontic brackets. The objectives of this study was to investigate the shear bond strength (SBS) of self-adhesive resin cements on etched on non-etched surfaces in vitro and to assess their fluoride release features. Materials and Methods Four fluoride-releasing dual-cure self-adhesive resin cements were investigated. For SBS experiment, 135 freshly extracted human maxillary premolars were used and divided into nine groups of 15 teeth. In the control group, brackets were cemented by Transbond XT (3M Unitek, USA), in four groups self-adhesive resin cements were used without acid-etching and in four groups self-adhesive cements were applied on acid-etched surfaces and the brackets were then deboned in shear with a testing machine. Adhesive remnant index (ARI) scores were also calculated. For fluoride release investigation, 6 discs were prepared for each self-adhesive cement. Transbond XT and Fuji Ortho LC (GC, Japan) served as negative and positive control groups, respectively. The fluoride release of each disc into 5 ml of deionized water was measured at days 1, 2, 3, 7, 14, 28, and 56 using a fluoride ion-selective electrode connected to an ion analyzer. To prevent cumulative measurements, the storage solutions were changed daily. Results The SBS of brackets cemented with Transbond XT were significantly higher compared to self-adhesives applied on non-etched surfaces (P<0.001). However, when the self-adhesive resin cements were used with enamel etching, no significant differences was found in the SBS compared to Transbond XT, except for Breeze. The comparisons of the ARI scores indicated that bracket failure modes were significantly different between the etched and non-etched groups. All self-adhesive cements released clinically sufficient amounts of fluoride for an extended period of time. Conclusion For the tested cements, the strongest bonds were obtained by enamel acid-etching prior to bracket bonding. All the self-adhesive resin cements had significant long-term fluoride release and could be recommended as suitable fluoride-releasing orthodontic bonding materials.

Ramazanzadeh, Barat Ali; Merati, Mohsen; Shafaee, Hooman; Dogon, Leon; Sohrabi, Keyvan

2013-01-01

62

Influence of inorganic filler content on the radiopacity of dental resin cements.  

PubMed

Digital radiography was used to measure the radiopacity of 18 resin cements to determine the influence of inorganic filler content on radiopacity. Four disk specimens (n=4) of each light-curing cement were digitally radiographed alongside an aluminum step wedge using an intraoral sensor (XIOS Plus, Sirona, Germany), and their mean gray value measured. Percentage of filler by weight was determined using an analytical combustion furnace. Data were statistically analyzed using one-way ANOVA and Tukey's test (?=0.05). All materials were more radiopaque than dentin and 12 materials were more radiopaque than enamel. Filler percentage ranged between 17.36 to 53.56 vol% and radiopacity between 1.02 to 3.40 mm Al. There were no statistically significant differences in inorganic filler percentage and radiopacity among the different shades of the same material (p>0.05), but the highest radiopacity was measured for the material which contained a higher percentage of filler. PMID:22447061

Furtos, Gabriel; Baldea, Bogdan; Silaghi-Dumitrescu, Laura; Moldovan, Marioara; Prejmerean, Cristina; Nica, Luminita

2012-03-23

63

Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements.  

PubMed

This study evaluated: I) the effect of photo-activation through ceramics on the degree of conversion (DC) and on the Knoop hardness (KHN) of light- and dual-cured resin cements; and II) two different protocols for obtaining the spectra of uncured materials, to determine the DC of a dual-cured resin cement. Thin films of cements were photo-activated through ceramics [feldspathic porcelain (FP); lithium disilicate glass-ceramics of low translucency (e.max-LT), medium opacity (e.max-MO) and high translucency (e.max-HT); glass-infiltrated alumina composite (IC) and polycrystalline zirconia (ZR)] with thicknesses of 1.5 and 2.0 mm. DC was analyzed by Fourier transform infrared (FTIR) spectroscopy. Two protocols were used to obtain the spectra of the uncured materials: I) base and catalyst pastes were mixed, and II) thin films of base and catalyst pastes were obtained separately, and an average was obtained. KHN assessment was performed with cylindrical specimens. The results were analyzed by ANOVA and Tukey's test (?= 0.05). The light-cured cement showed higher DC (61.9%) than the dual-cured cement (55.7%). The DC varied as follows: FP (65.4%), e.max-HT (65.1%), e.max-LT (61.8%), e.max-MO (60.9%), ZR (54.8%), and IC (44.9%). The light-cured cement showed lower KHN (22.0) than the dual-cured (25.6) cement. The cements cured under 1.5 mm spacers showed higher KHN (26.2) than when polymerized under 2.0 mm ceramics (21.3). Regarding the two protocols, there were significant differences only in three groups. Thus, both methods can be considered appropriate. The physical and mechanical properties of resin cements may be affected by the thickness and microstructure of the ceramic material interposed during photo-activation. PMID:24036978

Calgaro, Patricia Angélica Milani; Furuse, Adilson Yoshio; Correr, Gisele Maria; Ornaghi, Bárbara Pick; Gonzaga, Carla Castiglia

64

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

65

Temporary zinc oxide-eugenol cement: eugenol quantity in dentin and bond strength of resin composite.  

PubMed

Uptake of eugenol from eugenol-containing temporary materials may reduce the adhesion of subsequent resin-based restorations. This study investigated the effect of duration of exposure to zinc oxide-eugenol (ZOE) cement on the quantity of eugenol retained in dentin and on the microtensile bond strength (?TBS) of the resin composite. The ZOE cement (IRM Caps) was applied onto the dentin of human molars (21 per group) for 1, 7, or 28 d. One half of each molar was used to determine the quantity of eugenol (by spectrofluorimetry) and the other half was used for ?TBS testing. The ZOE-exposed dentin was treated with either OptiBond FL using phosphoric acid (H?PO?) or with Gluma Classic using ethylenediaminetetraacetic acid (EDTA) conditioning. One group without conditioning (for eugenol quantity) and two groups not exposed to ZOE (for eugenol quantity and ?TBS testing) served as controls. The quantity of eugenol ranged between 0.33 and 2.9 nmol mg?¹ of dentin (median values). No effect of the duration of exposure to ZOE was found. Conditioning with H?PO? or EDTA significantly reduced the quantity of eugenol in dentin. Nevertheless, for OptiBond FL, exposure to ZOE significantly decreased the ?TBS, regardless of the duration of exposure. For Gluma Classic, the ?TBS decreased after exposure to ZOE for 7 and 28 d. OptiBond FL yielded a significantly higher ?TBS than did Gluma Classic. Thus, ZOE should be avoided in cavities later to be restored with resin-based materials. PMID:23841789

Koch, Tamara; Peutzfeldt, Anne; Malinovskii, Vladimir; Flury, Simon; Häner, Robert; Lussi, Adrian

2013-05-09

66

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

67

Adhesion of 10-MDP containing resin cements to dentin with and without the etch-and-rinse technique  

PubMed Central

PURPOSE This study evaluated the adhesion of 10-MDP containing self-etch and self-adhesive resin cements to dentin with and without the use of etch-and-rinse technique. MATERIALS AND METHODS Human third molars (N=180) were randomly divided into 6 groups (n=30 per group). Conventional (Panavia F2.0, Kuraray-PAN) and self-adhesive resin cements (Clearfil SA, Kuraray-CSA) were bonded to dentin surfaces either after application of 3-step etch-and-rinse (35% H3PO4 + ED Primer) or two-step self-etch adhesive resin (Clearfil SE Bond). Specimens were subjected to shear bond strength test using the universal testing machine (0.5 mm/min). The failure types were analyzed using a stereomicroscope and quality of hybrid layer was observed under a scanning electron microscope. The data (MPa) were analyzed using two-way ANOVA and Tukey's tests (?=.05). RESULTS Overall, PAN adhesive cement showed significantly higher mean bond strength (12.5 ± 2.3 - 14.1 ± 2.4 MPa) than CSA cement (9.3 ± 1.4 - 13.9 ± 1.9 MPa) (P<.001). Adhesive failures were more frequent in CSA cement groups when used in conjunction with two-step self-adhesive (68%) or no adhesive at all (66%). Hybrid layer quality was inferior in CSA compared to PAN cement in all conditions. CONCLUSION In clinical situations where bonding to dentin substrate is crucial, both conventional and self-adhesive resin cements based on 10-MDP can benefit from etch-and-rinse technique to achieve better quality of adhesion in the early clinical period.

Sen, Deniz; Tuncelli, Betul; Ozcan, Mutlu

2013-01-01

68

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

69

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

70

Si-based thin film coating on Y-TZP: Influence of deposition parameters on adhesion of resin cement  

NASA Astrophysics Data System (ADS)

This study evaluated the influence of deposition parameters for Si-based thin films using magnetron sputtering for coating zirconia and subsequent adhesion of resin cement. Zirconia ceramic blocks were randomly divided into 8 groups and specimens were either ground finished and polished or conditioned using air-abrasion with alumina particles coated with silica. In the remaining groups, the polished specimens were coated with Si-based film coating with argon/oxygen magnetron discharge at 8:1 or 20:1 flux. In one group, Si-based film coating was performed on air-abraded surfaces. After application of bonding agent, resin cement was bonded. Profilometry, goniometry, Energy Dispersive X-ray Spectroscopy and Rutherford Backscattering Spectroscopy analysis were performed on the conditioned zirconia surfaces. Adhesion of resin cement to zirconia was tested using shear bond test and debonded surfaces were examined using Scanning Electron Microscopy. Si-based film coating applied on air-abraded rough zirconia surfaces increased the adhesion of the resin cement (22.78 ± 5.2 MPa) compared to those of other methods (0-14.62 MPa) (p = 0.05). Mixed type of failures were more frequent in Si film coated groups on either polished or air-abraded groups. Si-based thin films increased wettability compared to the control group but did not change the roughness, considering the parameters evaluated. Deposition parameters of Si-based thin film and after application of air-abrasion influenced the initial adhesion of resin cement to zirconia.

Queiroz, José Renato Cavalcanti; Nogueira Junior, Lafayette; Massi, Marcos; Silva, Alecssandro de Moura; Bottino, Marco Antonio; Sobrinho, Argemiro Soares da Silva; Özcan, Mutlu

2013-10-01

71

Cytotoxicity Evaluation of Self Adhesive Composite Resin Cements by Dentin Barrier Test on 3D Pulp Cells  

PubMed Central

Objectives: The aim of this study was to evaluate the effects of five self-etch dental composite resin cements on the cell viability of bovine dental papilla-derived cells. Methods: The cytotoxicity of composite resin cements (Rely X Unicem Clicker, 3M ESPE; MaxCem; KERR, Panavia F 2.0; Kuraray, BisCem; Bisco and Bistite II DC; Tokuyama) was analyzed in a dentin barrier test device using three-dimensional (3D) pulp cell cultures. A commercially available cell culture perfusion chamber was separated into two compartments by 500 ?m dentin disc. The three dimensional cultures placed on a dentin disk held in place by a special biocompatible stainless-steel holder. Test materials were introduced into the upper compartment in direct contact with the cavity side of the dentin disks according to the manufacturer’s instructions. Subsequently, the pulpal part of the perfusion chamber containing the cell cultures was perfused with medium (2 ml/h). After an exposure period of 24 h, the cell survival was determined by the MTT assay. Statistical analyses were performed using the Mann–Whitney U-test. Results: In dentin barrier test, cell survival was similar with Maxcem and negative control group (P>.05), and all other tested materials were cytotoxic for the three dimensional cell cultures (P>.05). Conclusions: The significance of composite resin cements is being more important in dentistry. The cytotoxic potencies demonstrated by these materials might be of clinical relevance. Some composite resin cements include biologically active ingredients and may modify pulp cell metabolism when the materials are used in deep cavities or directly contact pulp tissue.

Ulker, Hayriye Esra; Sengun, Abdulkadir

2009-01-01

72

A 12-month clinical comparison of resin-modified light-activated adhesives for the cementation of orthodontic molar bands  

Microsoft Academic Search

A clinical trial is reported on the retention rates of resin-modified light-activated adhesives for the cementation of orthodontic molar bands. Fifty consecutive cases were fully banded and monitored over 12 months. Fuji II LC (GC International) recorded a failure rate of 2.9%, Bandlok (Reliance Orthodontic Products) 8.1%, with Ketac Cem (Espe) chemical cure 3.5%. There were no statistically significant differences

John P. Fricker

1997-01-01

73

Effect of ceramic surface treatment on the shear bond strength of a resin cement to different ceramic systems.  

PubMed

This study evaluated three surface treatments and their effect on the shear bond strength between a resin cement and one of three ceramics. The ceramic surfaces were evaluated with scanning electron microscopy (SEM) as well. Specimens were treated with 50 ?m aluminum oxide airborne particles, 10% hydrofluoric acid etching, or a combination of the two. Using a matrix with a center hole (5.0 mm x 3.0 mm), the ceramic bonding areas were filled with resin cement following treatment. The specimens were submitted to thermal cycling (1,000 cycles) and the shear bond strength was tested (0.5 mm/minute). The failure mode and the effect of surface treatment were analyzed under SEM. Data were submitted to ANOVA and a Tukey test (? = 0.05). Duceram Plus and IPS Empress 2 composite specimens produced similar shear bond strength results (p > 0.05), regardless of the treatment method used. Hydrofluoric acid decreased the shear bond strength of In-Ceram Alumina specimens. For all materials, surface treatments changed the morphological surface. All treatments influenced the shear bond strength and failure mode of the ceramic/resin cement composites. PMID:23032240

Ribeiro, Joao Gustavo Rabelo; Segalla, Jose Claudio Martins; Perez, Fabiano; Ribeiro, Jose Carlos Rabelo; Moyses, Marcos Ribeiro

74

Comparison of the apical seal obtained by a dual-cure resin based cement or an epoxy resin sealer with or without the use of an acidic primer.  

PubMed

This study compared the apical leakage of roots obturated with gutta-percha using either a dual-cure resin based cement (Panavia F) or an epoxy-resin sealer (Thermaseal plus) with or without the application of an acidic primer (ED Primer). Eighty-six single rooted canine teeth were decoronated, cleaned, and shaped by using hand and rotary instruments, randomly divided into four groups, and obturated as follows: group A (n = 20): ED Primer applied followed by thermoplastized obturation with gutta-percha and Thermaseal Plus sealer; group B (n = 20): thermoplastized obturation with gutta-percha and Thermaseal Plus; group C (n = 20): ED primer applied followed by thermoplastized obturation with gutta-percha and Panavia F; group D (n = 20): thermoplastized obturation with gutta-percha and Panavia F. Both a negative control (n = 3; entire root coated with wax) and a positive control (n = 3; obturated with only a fitted master cone) were included in the study. Groups A, B, C, D, and the controls were immersed in molten sticky wax, leaving the apical 2-mm exposed, and quickly chilled. All teeth were immersed in 1% methylene blue dye solution for 10 days, rinsed, and sectioned longitudinally. Apical dye penetration was measured stereomicroscopically at 10-fold magnification. The analysis of variance and Duncan Multiple Range were used for result analysis. The specimens obturated with gutta-percha and an epoxy-resin sealer (with or without an acidic primer) demonstrated significantly less linear dye penetration than specimens obturated with gutta-percha and the dual-cure, resin-based cement (with or without an acidic primer). PMID:12398172

Britto, Leandro R; Borer, Robert E; Vertucci, Frank J; Haddix, James E; Gordan, Valeria V

2002-10-01

75

Influence of alloy microstructure on the microshear bond strength of basic alloys to a resin luting cement.  

PubMed

The aim of this study was to evaluate the influence of microstructure and composition of basic alloys on their microshear bond strength (µSBS) to resin luting cement. The alloys used were: Supreme Cast-V (SC), Tilite Star (TS), Wiron 99 (W9), VeraBond II (VBII), VeraBond (VB), Remanium (RM) and IPS d.SIGN 30 (IPS). Five wax patterns (13 mm in diameter and 4mm height) were invested, and cast in a centrifugal casting machine for each basic alloy. The specimens were embedded in resin, polished with a SiC paper and sandblasted. After cleaning the metal surfaces, six tygon tubes (0.5 mm height and 0.75 mm in diameter) were placed on each alloy surface, the resin cement (Panavia F) was inserted, and the excess was removed before light-curing. After storage (24 h/37°C), the specimens were subjected to µSBS testing (0.5 mm/min). The data were subjected to a one-way repeated measures analysis of variance and Turkey's test (?=0.05). After polishing, their microstructures were revealed with specific conditioners. The highest µSBS (mean/standard deviation in MPa) were observed in the alloys with dendritic structure, eutectic formation or precipitation: VB (30.6/1.7), TS (29.8/0.9), SC (30.6/1.7), with the exception of IPS (31.1/0.9) which showed high µSBS but no eutectic formation. The W9 (28.1/1.5), VBII (25.9/2.0) and RM (25.9/0.9) showed the lowest µSBS and no eutectic formation. It seems that alloys with eutectic formation provide the highest µSBS values when bonded to a light-cured resin luting cement. PMID:23306223

Bauer, José; Costa, José Ferreira; Carvalho, Ceci Nunes; Souza, Douglas Nesadal de; Loguercio, Alessandro Dourado; Grande, Rosa Helena Miranda

76

Comparison of resin cement adhesion to Y-TZP ceramic following manufacturers’ instructions of the cements only  

Microsoft Academic Search

The objectives of this study were (1) to evaluate the bond strength of four resin materials with various chemical compositions\\u000a following the manufacturers’ instructions only and (2) to test their durability in dry and thermal aged conditions when they\\u000a were bonded to zirconia ceramic. Four types of resin materials namely, Panavia F 2.0, Multilink, SuperBond and Quadrant Posterior\\u000a Dense, were

Mutlu Özcan; Sandra Kerkdijk; Luiz Felipe Valandro

2008-01-01

77

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

78

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

79

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

80

An effect of immediate dentin sealing on the shear bond strength of resin cement to porcelain restoration  

PubMed Central

PURPOSE The aim of this study was to determine differences in shear bond strength to human dentin using immediate dentin sealing (IDS) technique compared to delayed dentin sealing (DDS). MATERIALS AND METHODS Forty extracted human molars were divided into 4 groups with 10 teeth each. The control group was light-cured after application of dentin bonding agent (Excite® DSC) and cemented with Variolink® II resin cement. IDS/SE (immediate dentin sealing, Clearfil™ SE Bond) and IDS/SB (immediate dentin sealing, AdapterTM Single Bond 2) were light-cured after application of dentin bonding agent (Clearfil™ SE Bond and Adapter™ Sing Bond 2, respectively), whereas DDS specimens were not treated with any dentin bonding agent. Specimens were cemented with Variolink® II resin cement. Dentin bonding agent (Excite® DSC) was left unpolymerized until the application of porcelain restoration. Shear strength was measured using a universal testing machine at a speed of 5 mm/min and evaluated of fracture using an optical microscope. RESULTS The mean shear bond strengths of control group and IDS/SE group were not statistically different from another at 14.86 and 11.18 MPa. Bond strength of IDS/SE group had a significantly higher mean than DDS group (3.14 MPa) (P < .05). There were no significance in the mean shear bond strength between IDS/SB (4.11 MPa) and DDS group. Evaluation of failure patterns indicates that most failures in the control group and IDS/SE groups were mixed, whereas failures in the DDS were interfacial. CONCLUSION When preparing teeth for indirect ceramic restoration, IDS with Clearfil™ SE Bond results in improved shear bond strength compared with DDS.

Cho, In-Ho

2010-01-01

81

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

82

The leachability and mechanical integrity of simulated decontamination resin wastes solidified in cement and vinyl ester-styrene  

SciTech Connect

The rate of release of organic decontamination reagents were measured for mixed-bed resins solidified in Portland cement and vinyl ester-styrene. The intent is to evaluate the effect of composite size on the release rate to determine if experiments on small laboratory samples can be used to predict the behavior of full size waste forms. The effects of chelating agents on the release of Co-60 from cementitious waste forms is addressed. Cracking during leaching was also investigated and reasons for its occurrence outlined. 26 refs., 32 figs., 13 tabs.

Soo, P.; Milian, L.W.; Piciulo, P.L.

1988-05-01

83

Effect of loading weight on bond durability of composite-type resin cement under cyclic impact test (part 2). Loading with light weight of 100-120g  

Microsoft Academic Search

The bond durability of composite-type resin cement was evaluated by means of cyclic impact tests using three different loads. In terms of experimental setup, a casting alloy, 12%Au-Pd-Ag, was used as the adherend and bonded to a cast block using a composite-type cement (Bistite II). A shear load ? using plungers of three different weights at 100, 110, and 120

Masahiro OHSAWA; Mamoru FUJIWARA; Yoshihiko HAYASHI

2009-01-01

84

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

85

Analysis of marginal adaptation and sealing to enamel and dentin of four self-adhesive resin cements.  

PubMed

This in vitro study compared the marginal adaptation of all-ceramic MOD-inlays luted to human molars with four self-adhesive resin cements. Thirty-two human third molars were randomly assigned to four test groups (n = 8 per group). MOD cavities were prepared with approximal finishing lines in dentin and enamel. All-ceramic Empress 2 inlays were luted with four self-adhesive cements (Clearfil SA, iCEM, Bifix SE, seT). Oral stress was simulated by 90 day storage in water as well as by thermal and mechanical loading (TCML, 1.2 × 10(6) × 50 N, 6,000 × 5°/55°, 1.6 Hz). The marginal fit was evaluated by scanning electron microscopy (SEM) and dye penetration. Data were analyzed with the ANOVA/Tukey's test (? = 0.05). The SEM investigation of the gingival cement margins (cement-tooth interface) showed values of perfect margin [percent] (means ± SD) after simulated aging between 84 ± 9% and 95 ± 5% for enamel and 80 ± 9% and 92 ± 3% for dentin. In enamel, seT showed significantly higher marginal integrity than iCEM after water storage and TCML (post hoc; p = 0.011). Furthermore, the marginal adaptation of iCEM in enamel deteriorated by simulated aging (p = 0.014, ANOVA). Mean values of dye penetration (percentage of dye entry into dentin) at the investigated restorations margins ranged between 3% and 8% for enamel and 12% and 22% for dentin. Clearfil SA, iCEM, and seT showed lower dye penetration in enamel than in dentin (Clearfil SA: p = 0.013, iCEM: p = 0.044, seT: p = 0.003). The results suggest that the four self-adhesive luting agents investigated seem to successfully bond to dentin-restricted as well as to enamel-restricted cavities, predicting good clinical performance. PMID:21327799

Aschenbrenner, Carina Maria; Lang, Reinhold; Handel, Gerhard; Behr, Michael

2011-02-16

86

Carbon14 behavior in a cement-dominated environment: Implications for spent CANDU resin waste disposal  

Microsoft Academic Search

Cement based waste forms and concrete engineered barriers are expected to play a key role in providing [sup 14]C waste containment and control [sup 14]C migration for time periods commensurate with its hazardous life of about 50,000 years. The main thrust of this study was, therefore, to evaluate the performance of cement based waste forms with regard to [sup 14]C

R. Dayal; E. J. Reardon

1994-01-01

87

Long term water storage deteriorates bonding of composite resin to alumina and zirconia short communication.  

PubMed

Objective of this study was to evaluate the effects of long term water storage and ageing on the bond strength of resin composite cement to yttria-stabilized zirconium dioxide (zirconia) and dialuminium trioxide (alumina). Substrate specimens of alumina and zirconia were air particle abraded with dialuminium trioxide before priming and application of composite resin. Priming was made with gamma metharyloxy-trimethoxysilane or acryloxypropyl-trimethoxysilane monomer after which the intermediate dimethacrylate resin was applied and photopolymerized. This was followed by curing particulate composite resin cement (Relyx ARC) to the substrate as a resin stub. The ageing methods of the specimens (n=6) were: (1) they stored four years in 37±1ºC distilled water, (2) thermocycled 8000 times between 55±1ºC and 5±1ºC, (3) stored first in water for four years and then thermocycled. Specimens which were stored dry, were used as controls. Bonding of composite resin was measured by shear-bond strength test set-up. Both thermocycling and long-term water storage decreased significantly shear bond strength values compared to the control group (from the level of 20 MPa to 5 MPa) regardless of the used primer or the type of the substrate. Combination of four years water storage and thermocyling reduced the bond strength even more, to the level of two to three megapascals. In can be concluded that water storage and thermocycling itselves, and especially combination of water storage and thermocycling can cause considerable reduction in the bond strength of composite resin cement to alumina and zirconia. PMID:24167535

Heikkinen, T T; Matinlinna, J P; Vallittu, P K; Lassila, L V J

2013-09-30

88

Long Term Water Storage Deteriorates Bonding of Composite Resin to Alumina and Zirconia Short Communication  

PubMed Central

Objective of this study was to evaluate the effects of long term water storage and ageing on the bond strength of resin composite cement to yttria-stabilized zirconium dioxide (zirconia) and dialuminium trioxide (alumina). Substrate specimens of alumina and zirconia were air particle abraded with dialuminium trioxide before priming and application of composite resin. Priming was made with gamma metharyloxy-trimethoxysilane or acryloxypropyl-trimethoxysilane monomer after which the intermediate dimethacrylate resin was applied and photopolymerized. This was followed by curing particulate composite resin cement (Relyx ARC) to the substrate as a resin stub. The ageing methods of the specimens (n=6) were: (1) they stored four years in 37±1ºC distilled water, (2) thermocycled 8000 times between 55±1ºC and 5±1ºC, (3) stored first in water for four years and then thermocycled. Specimens which were stored dry, were used as controls. Bonding of composite resin was measured by shear-bond strength test set-up. Both thermocycling and long-term water storage decreased significantly shear bond strength values compared to the control group (from the level of 20 MPa to 5 MPa) regardless of the used primer or the type of the substrate. Combination of four years water storage and thermocyling reduced the bond strength even more, to the level of two to three megapascals. In can be concluded that water storage and thermocycling itselves, and especially combination of water storage and thermocycling can cause considerable reduction in the bond strength of composite resin cement to alumina and zirconia.

Heikkinen, T.T.; Matinlinna, J.P; Vallittu, P.K.; Lassila, L.V.J.

2013-01-01

89

Le Coulis Gravillonne a Liant Resineux un Revetement Mince Antiderapant pour Beton de Ciment (Chipped Resin-Based Scurries as Skid-Resistant Surfacings on Cement Concrete).  

National Technical Information Service (NTIS)

Chipped resin-based slurries are very thin skid-resistant wearing courses ranging from about 6 to 7 mm. They have been progressively developed through road and laboratory tests. Intended use is for surfacings on cement concrete roads and bridges, particul...

L. Hubrecht

1979-01-01

90

Evaluation of light transmission through different esthetic posts and its influence on the degree of polymerization of a dual cure resin cement  

PubMed Central

Aim: To measure the light transmission through different esthetic posts and to evaluate the degree of polymerization of dual cure resin cement cured through these posts. Materials and Methods: The posts were divided into two experimental groups i.e. Group A (D.T. Light post); Group B (D.T. White post) and control i.e. Group C (metal post), each group having 10 samples. Posts of each group were illuminated with curing light and photographs were taken keeping the parameters standardized to evaluate the intensity of light transmission at different levels. The degree of polymerization of dual cure resin cement was evaluated using Fourier Transform Infrared spectroscopy. The data obtained was subjected to statistical analysis. Results: D.T. Light post showed highest light transmission and degree of polymerization. The light intensity decreased from cervical to apical for both esthetic post but the decrease from middle to apical third was insignificant for D.T. White post group. No light transmission was detected in metal post but the degree of polymerization decreased significantly from cervical to middle third. Conclusion: Cementation of fibre post with superior light transmitting ability using dual cured resin cement resulted in increased degree of polymerization.

Taneja, Sonali; Kumari, Manju; Gupta, Anupama

2013-01-01

91

Chemical analysis and bonding reaction of RelyX Unicem and Bifix composites—A comparative study  

Microsoft Academic Search

ObjectivesThe chemical and physical properties of the dual curing luting composites RelyX Unicem (3M ESPE) and Bifix (VOCO) were analyzed with regard to their elemental composition, surface morphology and polymerization reaction. The bonding of both materials to hydroxyapatite (HAp) was studied.

Hans U. V. Gerth; Till Dammaschke; Harald Züchner; Edgar Schäfer

2006-01-01

92

Synthesis, formulation and evaluation of novel zinc-calcium phosphate-based adhesive resin composite cement  

Microsoft Academic Search

Three novel adhesive oligomers having carboxylic acid and methacrylate groups were synthesized, characterized and used to formulate composite bone cements with newly synthesized zinc-calcium-silicate phosphate. The optimal formulation was determined based on types of oligomer, oligomer\\/diluent ratio, initiator concentration, and filler level using compressive strength (CS) and curing time (CT) as screening tools. Shrinkage, exotherm and aging of the formed

Dong Xie; IL-Doo Chung; Guigui Wang; Dingsong Feng; Jimmy Mays

2004-01-01

93

Evaluation of push-out bond strength of two fiber-reinforced composite posts systems using two luting cements in vitro  

PubMed Central

Introduction: The concept of using a “post” for the restoration of teeth has been practiced to restore the endodontically treated tooth. Metallic posts have been commonly used, but their delirious effects have led to the development of fiber-reinforced materials that have overcome the limitations of metallic posts. The use of glass and quartz fibers was proposed as an alternative to the dark color of carbon fiber posts as far as esthetics was concerned. “Debonding” is the most common failure in fiber-reinforced composite type of posts. This study was aimed to compare the push-out bond strength of a self-adhesive dual-cured luting agent (RelyX U100) with a total etch resin luting agent (Variolink II) used to cement two different FRC posts. Materials and Methods: Eighty human maxillary anterior single-rooted teeth were decoronated, endodontically treated, post space prepared and divided into four groups (n = 20); Group I: D.T. light post (RTD) and Variolink II (Ivoclare vivadent), Group II: D.T. light post (RTD) and RelyX U100 (3M ESPE), Group III: Glassix post (Nordin) and Variolink II (Ivoclare vivadent) and Group IV: Glassix post (Nordin) and RelyX U100 (3M ESPE). Each root was sectioned to get slices of 2 ± 0.05-mm thickness. Push-out tests were performed using a triaxial loading frame. To express bond strength in megapascals (Mpa), load value recorded in Newton (N) was divided by the area of the bonded interface. After testing the push-out strengths, the samples were analyzed under a stereomicroscope. Results: The mean values of the push-out bond strength show that Group I and Group III had significantly higher values than Group II and Group IV. The most common mode of failure observed was adhesive between dentin and luting material and between post and luting material. Conclusions: The mean push-out bond strengths were higher for Groups I and III where Variolink II resin cement was used for luting the fiber post, which is based on the total etch adhesive approach. In most of the samples, failure was observed between cement–dentine interface, followed by post–cement interface, which shows difficulty in bonding between post–cement–dentine interface.

Kadam, Ajay; Pujar, Madhu; Patil, Chetan

2013-01-01

94

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

95

Effects of metal primers on bonding of adhesive resin cement to noble alloys for porcelain fusing.  

PubMed

This study evaluated the effects of metal primers on the bonding of adhesive resin to four pure metals (Au, Pd, Ag, Cu) and two noble alloys for porcelain fusing (high-gold and high-palladium content alloys). Bonding surface was polished with 600-grit silicon carbide paper and primed with one of the three metal primers (V-Primer, Metaltite, and M.L. Primer). Bonded specimens were fabricated by applying adhesive resin (Super-Bond C&B) on the primed surface. Shear bond strength (SBS) was determined both before and after thermocycling (4-60 degrees C for 2,000 cycles). The highest SBS values to each pure metal after thermocycling were 33.5 MPa for Au by M.L. Primer, 35.0 MPa for Ag by V-Primer, and 34.4 MPa for Cu by Metaltite. SBS to high-gold content alloy after thermocycling was 33.3 MPa by M.L. Primer. None of the primers was effective for pure Pd and high-palladium content alloy after thermocycling. PMID:20379028

Okuya, Nobuhiro; Minami, Hiroyuki; Kurashige, Hisanori; Murahara, Sadaaki; Suzuki, Shiro; Tanaka, Takuo

2010-03-01

96

The processing, properties, and applications of calcium aluminate–phenol resin composite 1 1 This paper was originally submitted to Advanced Cement Based Materials on 15 October 1997 and accepted on 22 March 1998. The paper was received at the Editorial Office of Cement and Concrete Research on 20 August 1998 and accepted in final form on 14 September 1998  

Microsoft Academic Search

The processing, properties, and a few applications of calcium aluminate–phenol resin composite with very high flexural strength are discussed. This composite contains a very large amount of cement (70 vol%) but shows unusual engineering properties, which have not yet been achieved by traditional cement-based materials. The flexural strength of the composite is found to be 120 to 220 MPa; in

G. K. Dinilprem Pushpalal; Tadashi Kobayashi; Toshio Kawano; Naomi Maeda

1999-01-01

97

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

98

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

99

Micromechanical properties of veneer luting resins after curing through ceramics  

Microsoft Academic Search

The aim of this study was to assess the performance of light-cured luting resin after curing under the ceramic restoration\\u000a in comparison to dual-cured luting resin, by evaluating the micromechanical properties. Two hundred seventy thin luting composite\\u000a films of ca. 170 ?m in thickness were prepared by using two light-cured luting resins (Variolink Veneer, Ivoclar Vivadent;\\u000a RelyX Veneer, 3M ESPE) and

Elif Öztürk; Reinhard Hickel; ?ükran Bolay; Nicoleta Ilie

100

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

101

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

102

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

103

Influence of eugenol on the push-out bond strengths of fiber posts cemented with different types of resin luting agents.  

PubMed

This study evaluated the influence of eugenol on the push-out bond strengths of fiber posts cemented with different types of resin luting agents. Seventy-two extracted maxillary single-rooted canine teeth were randomly divided into two groups of 36 teeth. Group 1, the control group, was filled with gutta-percha only (i.e., did not receive eugenol), whereas group 2 was filled with a eugenol-containing sealer. All root canals were filled and each group was divided into three subgroups. The posts in each subgroup were cemented with the following materials: subgroup 1 with a 2-step self-etching adhesive system (Clearfil Liner Bond 2V + Panavia F); subgroup 2 with a 1-step self-etching adhesive (Panavia F); and subgroup 3 with a self-adhesive (Clearfil SA Cement). Dislodgement resistance was measured using a universal testing machine. All data were subjected to ANOVA using a factorial design and Tukey test (? = 0.05). The use of the eugenol-containing sealer significantly reduced the push-out bond strength of the fiber post (P < 0.05). The push-out bond strength of Panavia F was significantly higher than those of the other groups filled with the eugenol-containing sealer (P < 0.05). The Panavia F group was less susceptible to the inhibiting effect of eugenol than were the other evaluated groups when the fiber post was cemented in the canals filled with the eugenol-containing sealer. PMID:23011473

Ozcan, Erhan; Cetin, Ali Riza; Capar, Ismail Davut; Tunçdemir, Ali Riza; Aydinbelge, Hale Ari

2012-07-28

104

Effect of loading weight on bond durability of composite-type resin cement under cyclic impact test (part 2). Loading with light weight of 100-120 g.  

PubMed

The bond durability of composite-type resin cement was evaluated by means of cyclic impact tests using three different loads. In terms of experimental setup, a casting alloy, 12% Au-Pd-Ag, was used as the adherend and bonded to a cast block using a composite-type cement (Bistite II). A shear load--using plungers of three different weights at 100, 110, and 120 g--was dropped from a 3-mm height onto a small piece of the casting alloy until debonding. The cycle numbers that caused debonding were 1756 +/- 680 x 10(4) times for 100 g, 1403 +/- 515 x 10(4) times for 110 g, and 420 +/- 200 x 10(4) times for 120 g, respectively. Therefore, the group loaded with 120 g showed a significantly lower value as compared to the other two groups. On the fracture mode of the cement, it was a bulk fracture regardless of the loading weight employed in this study--the same result obtained in a previous study where heavier weights were employed. PMID:19496399

Ohsawa, Masahiro; Fujiwara, Mamoru; Hayashi, Yoshihiko

2009-03-01

105

Influence of different power outputs of intraoral Nd:YAG laser on shear bond strength of a resin cement to nickel-chromium dental alloy.  

PubMed

Up to now, there is no any experience about the application of dental lasers to bond resin composites to metal surfaces in dentistry. The aim of this preliminary study was to evaluate if the laser irradiation of ceramic-covered alloy surface would improve the bond strength of resin to metal, and if different parameters of laser output may influence the strength of this bond. Fifty three cylinders (thickness of 5 mm and diameter of 10 mm) were made up of a commercially available nickel-chromium alloy by lost-wax technique. Forty prepared specimens were divided into four groups. Five specimens in each group were covered by slurry of dental opaque porcelain and irradiated by Nd:YAG laser using different output parameters for each group. Other five specimens in each group were treated using the same laser parameters without porcelain covering. Five sandblasted specimen served as control group. Panavia F2.0 was bonded on the metal surfaces using polyethylene tubes. In ceramic-coated specimens, silane was applied to achieve chemical bond between silica particles and resin cement. All specimens were thermocycled and subjected to shear bond strength (SBS) test (50 kgf at 0.5 mm/min). Two specimens of each ceramic-coated laser-treated groups were studied using scanning electron microscopy and wavelength dispersive X-ray spectroscopy which showed stabilization of silica particles on the metal surface. ANOVA procedure showed that although shear bond strength was significantly higher in porcelain-covered laser treated samples, but the effect of power output of laser irradiation was not significant (P = 0.917). There were no statistically significant difference between SBS in control samples and laser treated specimens without porcelain covering. It can be concluded that Nd:YAG laser surface treatment may improve the silica coating of alloy surface to achieve better resin-metal bond. PMID:22588684

sadat Madani, Azam; Astaneh, Pedram Ansari; Shahabi, Sima; Nakhaei, Mohammad Reza; Bagheri, Hossein G; Chiniforush, Nasim

2012-05-17

106

Degree of conversion of luting resins around ceramic inlays in natural deep cavities: a micro-Raman spectroscopy analysis.  

PubMed

This study evaluated the degree of conversion (%DC) of luting agents around ceramic inlays placed in deep natural cavities. Thirty-six cylindrical Class I cavities (diameter = 4 mm, depth = 4 mm) were prepared in freshly extracted human teeth and randomly divided according to the luting materials used for luting CAD/CAM fabricated inlays (Empress CAD). The dual-cure resin cements Clearfil Esthetic Cement and Variolink II Low and the light-cure composites Grandio Flow and Grandio were luted using the total-etch technique. The self-adhesive dual-cure cements RelyX Unicem and Maxcem Elite were used as recommended by the manufacturer. All of the restorations were photo-activated using a quartz halogen unit (Elipar TriLight; 750 mW/cm2) for 40 seconds. After 24 hour dry-storage in the dark, all the teeth were vertically sectioned into two halves (n = 12 per group) using a slow-speed diamond-saw in the bucco-vestibular direction under constant water lubrication to avoid specimen heating. The DC of the luting materials was measured by vibrational spectroscopy using a micro-Raman spectrometer at depths of 1, 3 and 4 mm on each side of the tooth halves (n = 24). Disc-shaped samples were produced for measurement of the maximum %DC of each material. Two-way ANOVA and the Student-Newman-Keuls post-hoc test were used in the statistical analysis (alpha = 0.05). All the materials showed no statistical differences in degree of conversion at all tested depths, except for Grandio Flow and Maxcem Elite. Dual-cure and light-cure luting materials showed polymerization homogeneity around ceramic inlays, although dual-cure conventional resin cements tended to show an overall higher conversion. PMID:20945750

Lohbauer, Ulrich; Pelka, Matthias; Belli, Renan; Schmitt, Johannes; Mocker, Eike; Jandt, Klaus D; Müller, Frank A

107

Solidification of ion exchange resin wastes  

SciTech Connect

Solidification media investigated included portland type I, portland type III and high alumina cements, a proprietary gypsum-based polymer modified cement, and a vinyl ester-styrene thermosetting plastic. Samples formulated with hydraulic cement were analyzed to investigate the effects of resin type, resin loading, waste-to-cement ratio, and water-to-cement ratio. The solidification of cation resin wastes with portland cement was characterized by excessive swelling and cracking of waste forms, both after curing and during immersion testing. Mixed bed resin waste formulations were limited by their cation component. Additives to improve the mechanical properties of portland cement-ion exchange resin waste forms were evaluated. High alumina cement formulations dislayed a resistance to deterioration of mechanical integrity during immersion testing, thus providing a significant advantage over portland cements for the solidification of resin wastes. Properties of cement-ion exchange resin waste forms were examined. An experiment was conducted to study the leachability of /sup 137/Cs, /sup 85/Sr, and /sup 60/Co from resins modified in portland type III and high alumina cements. The cumulative /sup 137/Cs fraction release was at least an order of magnitude greater than that of either /sup 85/Sr or /sup 60/Co. Release rates of /sup 137/Cs in high alumina cement were greater than those in portland III cement by a factor of two.Compressive strength and leach testing were conducted for resin wastes solidified with polymer-modified gypsum based cement. /sup 137/Cs, /sup 85/Sr, and /sup 60/Co fraction releases were about one, two and three orders of magnitude higher, respectively, than in equivalent portland type III cement formulations. As much as 28.6 wt % dry ion exchange resin was successfully solidified using vinyl ester-styrene compared with a maximum of 25 wt % in both portland and gypsum-based cement.

Not Available

1982-08-01

108

Influence of calcium hydroxide dressing and acid etching on the push-out bond strengths of three luting resins to root canal dentin.  

PubMed

OBJECTIVES: This study aims to investigate the effects of calcium hydroxide (Ca(OH)2) dressing in root canals and the effects of subsequent acid etching on the adhesion of luting resins to root canals. MATERIALS AND METHODS: Root specimens were prepared from extracted human permanent molars. Specimen canals were (1) filled with etch-and-rinse (Nexus® third generation (NX3)) and two self-adhesive (RelyX Unicem, Maxcem Elite) luting resins, respectively; (2) dressed with Ca(OH)2 before Ca(OH)2 removal and luting resin filling; (3) dressed with Ca(OH)2 before Ca(OH)2 removal and post-cementation; or (4) treated as described in item (2) except that the canals were further etched with phosphoric acid before luting resin filling. Push-out bond strengths were measured and analyzed using one-way analysis of variance, and Fisher's multiple comparison tests provided a follow-up comparison among these four canal treatments. Attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to analyze the specimen surfaces. RESULTS: Ca(OH)2 dressing adversely affected the bond strengths to canal dentin of the three luting resins tested. Acid etching did not increase the bond strengths. Infrared analysis revealed that Ca(OH)2 dressing caused no structural changes on the dentin surface. XPS and SEM analyses revealed Ca(OH)2 remnants as the ultimate chemical cause leading to the decrease in bond strength. CONCLUSIONS: The bond strength of luting resin to dentin was affected by Ca(OH)2 dressing. Acid etching treatment could not increase the bond strength. CLINICAL RELEVANCE: Adhesion of the fiber post to the root canal wall may be compromised after Ca(OH)2 dressing. An effective method for complete removal of Ca(OH)2 dressing or increase of bond strength for luting resin needs to be developed. PMID:23686133

Lee, Bor-Shiunn; Lin, Yu-Chen; Chen, Sing-Fu; Chen, Shu-Yu; Chang, Che-Chen

2013-05-18

109

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

110

Comparing the reinforcing effects of a resin modified glassionomer cement, Flowable compomer, and Flowable composite in the restoration of calcium hydroxide-treated immature roots in vitro  

PubMed Central

One hundred and sixty human permanent central incisors were enlarged to a 120 file size after crown removal procedure to simulate immature teeth. The root canals were filled with calcium hydroxide and stored for 15 days (phase I), 30 days (phase II), 90 days (phase III), and 180 days (Phase IV). At the end of these selected time periods, calcium hydroxide was cleaned off the root canals of forty teeth that were randomly selected and obturated with gutta-percha points in the apical 2 mm of the root canals with a sealer. The specimens were further equally divided into four groups. Unrestored Group I served as control and the root canals of teeth in the other three group specimens were reinforced with resin modified glassionomer cement (RMGIC) (Group II), Flowable Compomer (Group III), and Flowable Composite (Group IV), respectively, using a translucent curing post. All specimens were subjected to compressive force using an Instron Testing machine, until fracture occurred. All the materials evaluated substantially reinforced the root specimens compared to the control. At the end of 180 days, Flowable composites showed maximum reinforcement compared to the other groups; however, no significant differences were found between the reinforcement capabilities of Flowable Compomer and RMGIC.

Prathibha, Rani S

2011-01-01

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

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

113

[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

114

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

115

Bond strength evaluation of three self-adhesive luting systems used for cementing composite and porcelain.  

PubMed

Self-adhesive resin cements were recently introduced with the purpose of simplifying the cementation technique, as they combine the use of adhesive and cement in a single application, eliminating the need for pretreatment of the tooth. In the present study a microtensile bond strength test (?-TBS) was used to compare three self-adhesives, an etch-and-rinse and a self-etch luting system, in the cementation of resin-based composite (RBC) and ceramic disks to dentin. Freshly extracted molars were transversally sectioned to expose flat, deep dentin surfaces. Cylindrical specimens (5 mm in diameter and 10 mm in height), consisting of RBC disks and leucite-based glass ceramic disks, were produced. The RBC disks were sandblasted with 50-?m Al2O3. The ceramic disks were conditioned with 9.5% hydrofluoric acid gel and silane application. All of the disks were then bonded to dentin surfaces employing five different luting agents: iCEM Self Adhesive (Heraeus Kulzer), MaxCem (Kerr Corporation), RelyX UniCem (3M ESPE), EnaCem HF (Micerium), and Panavia F2.0 (Kuraray-Dental). The products were applied according to the manufacturers' instructions. The specimens were sectioned perpendicular to the adhesive interface to produce multiple beams measuring approximately 1 mm2 in cross section. For each experimental group 12 beams were tested. The preterm failures were also taken into account. All of the specimen preparations were performed by the same operator. The beams were tested under tension at a crosshead speed of 0.5 mm/min until failure. Mean ?-TBS values were calculated for each group. Data were analyzed by a two-way analysis of variance, and multiple comparisons were performed using a Tukey test (?=0.05). The UniCem group showed the lowest number of preterm failures among the tested self-adhesive systems. When premature debondings were included in the mean value calculation, bond strength values for the UniCem group were statistically equal to or even higher than those achieved with the other self-adhesives, although these values were still statistically worse than those obtained using traditional multi-step luting agents. PMID:21864126

De Angelis, F; Minnoni, A; Vitalone, L M; Carluccio, F; Vadini, M; Paolantonio, M; D'Arcangelo, C

2011-08-24

116

Incineration of ion-exchange resins in a fluidized bed  

Microsoft Academic Search

Incineration of ion-exchange resins in a fluidized bed was studied on the pilot plant scale. Granular resins were incinerated mostly in the dry form, while powdered resins were incinerated in an ethanol-water mixture. Incineration converts the organic resin into inert oxide material, which can be immobilized for instance with cement. The weight of the ash was 1 to 20% and

M. Valkiainen; M. Nykyri

1982-01-01

117

Effect of Er,Cr:YSGG pretreatment on bond strength of fiber posts to root canal dentin using a self-adhesive resin cement.  

PubMed

The weak link in the adhesive luting of fiber posts to root canal dentin is at the cement-dentin interface. The aim of the present study was to evaluate the effect of Er,Cr:YSGG laser irradiation on push-out bond strength of fiber posts cemented to root canal dentin using a self-adhesive cement. A total of 30 sound human maxillary central incisors were equally divided into two groups after root canal treatment, decoronation and preparation of the post space. Teeth of group 1 were treated with the Er,Cr:YSGG laser, and teeth of group 2 (control) received no laser treatment. After cementation of fiber posts with Maxcem self-adhesive cement, 3-mm cervical, middle and apical sections were prepared from the roots. Then a push-out test was performed using a universal testing machine at a strain rate of 0.5 mm/min. Data were analyzed using two-way ANOVA and the Bonferroni test. Statistical significance was defined as P < 0.05. There was a significant difference in the mean bond strength values between groups 1 and 2 (P = 0.001), but there were no significant differences between the various root parts (P = 0.14). In addition, the cumulative effects of dentin treatment type and various root parts were not statistically significant (P = 0.41). The mean bond strength in the laser group was significantly higher than in the control group (P = 0.001, post hoc Bonferroni test).The failure mode was evaluated under a stereomicroscope at × 20 magnification. PMID:22370616

Mohammadi, Narmin; Savadi Oskoee, Siavash; Abed Kahnamoui, Mehdi; Bahari, Mahmoud; Kimyai, Soodabeh; Rikhtegaran, Sahand

2012-02-28

118

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

119

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

120

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

121

[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

122

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

123

Effect of two axial wall height preparations on the retentive properties of full crowns using three different cements.  

PubMed

This study evaluated how different tooth preparation heights and luting cements affected the retention of metallic full crowns. Tooth preparations were made on 60 extracted maxillary premolars with occluso-cervical heights of 4.0 or 5.0 mm. The nickel chromium (NiCr) metallic crowns in each group were subdivided randomly into three groups (n = 10); the samples in each group were cemented with either a self-adhesive resin cement, a conventional resin cement, or a zinc phosphate cement. Cementation was performed by applying 5.0 kg pressure in 50% relative humidity. Specimens were stored in 100% humidity at 37 degrees C for seven days, at which time they were subjected to a vertical tensile test with a universal testing machine at 0.5 mm/min. Data (Kgf) were analyzed by two-way ANOVA and Tukey's multiple comparisons tests (alpha = 0.01). There was a significant difference in mean force in the height preparations (P < 0.001) and in tensile strength (P < 0.001) among the resin cements. Regardless of the cement used, 5.0 mm high preparations showed significantly higher mean forces than the 4.0 mm high preparations. The self-adhesive resin cement showed significantly higher mean tensile strength than the conventional resin cement; the zinc phosphate cement displayed the lowest retention values. The self-adhesive resin cement displayed retention rates twice that of the zinc phosphate cement. PMID:18810919

Martins-Pinto, Marcio Guilherme; Pisani-Proenca, Jatyr; Erhardt, Maria Carolina Guilherme; Spielmann, Cezar; Del Castillo-Salmeron, Ramon; Lopes, Luis Artur Zenni

124

Method for permanently storing radioactive ion exchanger resins  

SciTech Connect

A method is claimed for forming a hardened product containing a radioactive ion exchanger resin in a condition for permanent, noncontaminating storage, by the steps of: providing, before fixing, a mass of such ion exchanger resin saturated in water, the resin being at least one resin selected from the group consisting of spherical resins and powdered resins; mixing the resin mass, with stirring, with a blast furnace cement having a composition which causes it to exhibit slow initial hardening, high sulfate resistance and low hydration heat and with a quantity of additional water equal in weight to 20% to 40% of the weight of the blast furnace cement; and allowing the resulting mixture to harden at room temperature.

Kunze, S.; Eden, G.; Koster, R.

1984-11-20

125

Adhesion strategy and early bond strengths of glass-fiber posts luted into root canals.  

PubMed

This study investigated the effect of coinitiator solutions and self-adhesive resin cement on the early retention of glass-fiber posts. Cylindrical glass-fiber posts were luted into 40 incisor roots with different adhesion strategies (n = 10): SB2, Single Bond 2 + conventional resin cement (RelyX ARC); AP, Scotchbond Multipurpose Plus (SBMP) activator + primer + ARC; APC, SBMP activator + primer + catalyst + ARC; and UNI, self-adhesive cement (RelyX Unicem). Pull-out bond strength results at 10 min after cementation showed APC > UNI > SB2 = AP (P < 0.05). The adhesion strategy significantly affected early bonding to root canals. PMID:22892880

Faria-e-Silva, André Luis; Mendonça, Adriano Augusto Melo; Garcez, Rosa Maria Viana de Bragança; Oliveira, Aline da Silva de; Moreira, Andressa Goicochea; Moraes, Rafael Ratto de

2012-08-14

126

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

127

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

128

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

129

Luting of ceramic crowns with a self-adhesive cement: Effect of contamination on marginal adaptation and fracture strength  

PubMed Central

Objectives: This study evaluated the percentages of continuous margins (%CM) and fracture strength (FS) of crowns made out from blocs of leucite-reinforced ceramic (IPS Empress CAD) and luted with a representative self-adhesive cement (RelyX Unicem) under four contaminating agents: saliva, water, blood, a haemostatic solution containing aluminium chloride (pH= 0.8) and a control group with no contamination. Study Design: %CM at both tooth-cement (TC) and cement-crown (CC) interfaces were determined before and after a fatigue test consisting of 600’000 chewing loads and 1’500 temperature cycles changing from 5º C to 50º C. Load to fracture was recorded on fatigued specimens. Kruskal-Wallis test was used to compare %CM and FS between the five groups with a level of confidence of 95%. Results: At the TC interface, no significant differences in marginal adaptation before loading could be detected between groups. After loading, a significant marginal degradation was observed in the group contaminated with aluminium chloride (52 ± 22 %CM) in respect to the other groups. No significant differences in %CM could be detected between the groups contaminated with saliva, water, blood and the control. At the CC interface, no significant differences in marginal adaptation were observed between the groups. The FS on loaded specimens was around 1637N, with no significant differences between groups as well. Conclusions: An adverse interaction of the highly acidic haemostatic agent with either dentin or the self-adhesive cement could explain the specimens’ marginal degradation. The self-adhesive cement tested in this study was no sensitive to moisture contamination either with saliva, water or blood. Key words:Marginal adaptation, RelyX Unicem, contamination, all-ceramic crowns.

Slavcheva, Slavena; Krejci, Ivo

2013-01-01

130

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

131

RESIN ATTRITION  

Microsoft Academic Search

ABS>Uranium metal is produced by the bomb reduction of UFâ with Mg. ; The slag from this reduction contains appreciable quantities of U, either in the ; metallic or the tetrafluoride form, in addition to the MgFâ. A process for ; recovering low enrichmeat U from this slag has gone into operation. A study of ; the causes of resin

G. R. Seiler; P. R. Ammann; A. B. Newey

1958-01-01

132

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

133

Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation.  

National Technical Information Service (NTIS)

Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive a...

C. Srinivas G. Sugilal P. K. Wattal

2003-01-01

134

Resin Chemistry  

Microsoft Academic Search

\\u000a During the ensuing years since the last phenolic resins book was published, many new and remarkable developments have occurred\\u000a in the realm of phenolic chemistry and are given in this chapter.\\u000a \\u000a \\u000a A critical examination of the first step or addition step (methylolation) in the preparation of resoles is described and how\\u000a it can be controlled and compared with the typical

Louis Pilato

2010-01-01

135

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

136

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

137

Leachability of decontamination reagents from cement waste forms  

SciTech Connect

Brookhaven National Laboratory, in order to provide technical information needed by the US Nuclear Regulatory Commission to evaluate the adequacy of near-surface disposal of decontamination wstes, has begun to study the leachability of organic reagents from solidified simulated decontamination wastes. Laboratory-scale cement waste forms containing EDTA, picolinic acid or simulated LOMI decontamination reagent were leach tested. Samples containing an organic reagent on either mixed bed ion-exchange resins or anion exchange resins were tested. A fixed interval leach procedure was used, as well as the standard procedure ANS 16.1. The leachability indices measured for the release of the acid from resin/cement composites are: 10.1 for EDTA on mixed bed resins; 9.1 for picolinic acid on mixed bed resins; 9.2 for picolinic acid on anion exchange resins; 8.8 for picolinic acid in forms containing simulated low oxidation metallic ion (LOMI) reagent on mixed bed resins and 8.7 for picolinic acid in forms containing simulated LOMI reagent on anion exchange resins. The leachability indices measured varied with leach time and the data indicate that the release mechanism may not be simply diffusion controlled. 5 references, 2 tables.

Piciulo, P.L.; Davis, M.S.; Adams, J.W.

1984-11-26

138

Is Adhesive Cementation of Endodontic Posts Necessary?  

Microsoft Academic Search

Recently, the appropriate, durable bond of adhesive systems and composite resin cements to retain endodontic posts was challenged. The question arises whether it would be possible to place glass fiber posts in a less technique sensitive conventional nonadhesive approach. The influence of nonadhesive, self-adhesive, and etch-and-rinse systems on load capability of postendodontic restorations was studied. Human maxillary central incisors were

Michael Naumann; Guido Sterzenbach; Martin Rosentritt; Florian Beuer; Roland Frankenberger

2008-01-01

139

Conventional and Contemporary Luting Cements: An Overview  

Microsoft Academic Search

Long-term clinical success of fixed prosthodontic restorations is influenced by many factors, one important factor being the\\u000a selection of an appropriate luting agent. No single luting agent is capable of meeting all the stringent requirements, which\\u000a is one reason why there is such a wide choice of luting agents currently available from conventional water-based to contemporary\\u000a adhesive resin cements. Introduction

Komal Ladha; Mahesh Verma

2010-01-01

140

In vivo Response of Bioactive PMMA-based Bone Cement Modified with Alkoxysilane and Calcium Acetate  

Microsoft Academic Search

The use of polymethylmethacrylate (PMMA)-based bone cement is popular in orthopedics for the fixation of artificial joints with bone. However, it has a major problem with prostheses loosening because of coverage by fibrous tissue after long-term implantation. Recently, a bioactive bone cement has been developed that shows direct bonding to living bone through modification of PMMA resin with ?-methacryloxypropyltrimethoxysilane (MPS)

Atsushi Sugino; Chikara Ohtsuki; Toshiki Miyazaki

2008-01-01

141

Phenolic Resin Syntactic Foams.  

National Technical Information Service (NTIS)

Syntactic foams were prepared from blends of six phenolic resins and carbon microbubbles. The compressive strength of the phenolic resin foams is equivalent to the strength of foams made from a polyimide resin. Ammonia evolved during the cure diffuses rap...

H. M. McIlroy

1980-01-01

142

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

143

Nano-mechanics of bone and bioactive bone cement interfaces in a load-bearing model  

Microsoft Academic Search

Many bioactive bone cements were developed for total hip replacement and found to bond with bone directly. However, the mechanical properties at the bone\\/bone cement interface under load bearing are not fully understood. In this study, a bioactive bone cement, which consists of strontium-containing hydroxyapatite (Sr-HA) powder and bisphenol-?-glycidyl dimethacrylate (Bis-GMA)-based resin, was evaluated in rabbit hip replacement for 6

G. X. Ni; Y. S. Choy; W. W. Lu; A. H. W. Ngan; K. Y. Chiu; Z. Y. Li; B. Tang; K. D. K. Luk

2006-01-01

144

[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

145

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

146

Thermocycling Effects on Resin Bond to Silicatized and Silanized Zirconia  

Microsoft Academic Search

Various techniques have been introduced to create a durable resin composite bond to sintered zirconia (Y-TZP). Shear bond strength values achieved through tribochemical treatment have been investigated in numerous studies, but less is reported about long-term durability. The objective here was to evaluate the effects of thermocycling and silane on shear bond strength of a composite luting cement to silicatized

Timo T. Heikkinen; Lippo V. J. Lassila; Jukka P. Matinlinna; Pekka K. Vallittu

2009-01-01

147

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

148

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

149

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

150

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

151

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

152

Performance of powder filled resin-bonded diamond wheels in the vertical dry grinding of tungsten carbide  

Microsoft Academic Search

Grinding performances of several resin-bonded diamond wheels containing copper, silicon carbide and carbon black fillers in the vertical dry grinding of cemented tungsten carbide are studied. The experimental results showed that the resin-bonded diamond wheel with the greatest amount of copper filler resulted in a relatively higher proportion of protrusive particles and partial breakage grits and a smaller number of

S. Y. Luo; Y. C. Liu; C. C. Chou; T. C. Chen

2001-01-01

153

Comparative study of nanomechanical properties of cements used in teeth restoration  

NASA Astrophysics Data System (ADS)

The discipline of dental science includes the diagnosis of disease in the mouth and teeth, its manifestations and the procedures involved in the restoration of their integrity and function. Restoration of lost tooth structure with suitable materials plays an integral part in the successful rehabilitation of oral tissues. Several factors influence the performance of dental restorations. These factors include the type of cement used to bond crown restoration to prepared teeth. The nanoindentation method was used to explore the mechanical properties of different types of resin cement polymerized using different techniques. A Nano Indenter XP (from MTS Nano Instruments, USA) was used for the experimental tests. A sample of 40 extracted human teeth were restored using two different resin cements: Variolink II (Ivoclar Vivadent, Liechtenstein) and Venus A2 (Heraeus Kulzer, Germany). Both resin cements are light-cured and one of them is self-cured so that the degree of polymerization would be higher. The data obtained for nanohardness and the Young's modulus were analysed using ANOVA to evaluate the influence of different factors (the resin cement and polymerization technique used, the position on the tooth-restoration interface) and to determine the best performance for restoration. The results obtained could give a useful indication of the choice of cementation technique and of the materials used for the restoration of lost tooth structure in different clinical cases.

Peluccio, M. S.; Bignardi, C.; Lombardo, S.; Montevecchi, F. M.; Carossa, S.

2007-10-01

154

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

155

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.

156

Phenolic resin syntactic foams  

Microsoft Academic Search

Syntactic foams were prepared from blends of six phenolic resins and carbon microbubbles. The compressive strength of the phenolic resin foams is equivalent to the strength of foams made from a polyimide resin. Ammonia evolved during the cure diffuses rapidly and is not bound by the foam.

McIlroy

1980-01-01

157

Polyester Resin Hazards  

Microsoft Academic Search

Polyester resins are being increasingly used in industry. These resins require the addition of catalysts and accelerators. The handling of polyester resin system materials may give rise to skin irritations, allergic reactions, and burns. The burns are probably due to styrene and organic peroxides. Atmospheric pollution from styrene and explosion and fire risks from organic peroxides must be prevented. Where

L. B. Bourne; F. J. M. Milner

1963-01-01

158

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

159

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

160

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

161

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

162

The effect of five silane coupling agents on the bond strength of a luting cement to a silica-coated titanium  

Microsoft Academic Search

ObjectivesThe adhesive performance of five silane coupling agents in adhering resin composite cement (3M ESPE) to silica-coated titanium was evaluated. Titanium was tribochemically silica-coated by using the Rocatec™ system.

Jukka P. Matinlinna; Lippo V. J. Lassila; Pekka K. Vallittu

2007-01-01

163

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

164

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

165

The effect of cure conditions on the stability of cement waste forms after immersion in water  

SciTech Connect

We investigated the effects of curing conditions on the stability of cement-solidified ion-exchange resins after immersion in water. The test specimens consisted of partially depleted mixed-bed bead resins solidified in one of three vendor-supplied Portland I cement formulations, in a reference cement formulation, or in a gypsum-based binder formulation. We cured samples prepared using each formulation in sealed containers for periods of 7, 14, or 28 days as well as in air or with an accelerated heat cure prior to 90-day immersion in water. Two cement formulations exhibited apparent Portland-cement-like behavior, i.e., compressive strength increased or stabilized with increasing cure time. Two cement formulations exhibited behavior apparently unlike that of Portland cement, i.e., compressive strength decreased with increasing cure time. Such non-Portland-cement-like behavior is correlated with higher waste loadings. The gypsum-based formulation exhibited approximately constant compressive strength with cure time. Accelerated heat cures may not give compressive strengths representative of real-time cures. Some physical deterioration (cracking, spalling) of the waste form occurs during immersion.

Siskind, B.; Adams, J.W.; Clinton, J.H.; Piciulo, P.L.; McDaniel, K.

1988-01-01

166

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

167

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

168

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

169

Retention of parallel-sided titanium posts cemented with six luting agents: An in vitro study  

Microsoft Academic Search

Purpose. This in vitro study compared the effectiveness of 6 luting systems on the retention of prefabricated titanium posts.Material and methods. A total of 120 single-rooted teeth were sectioned at the cementoenamel junction and treated endodontically. Roots were mounted in copper cylinders, and prefabricated, parallel-sided titanium posts were cemented according to the manufacturer’s instructions. Two resin-ionomer hybrid cements and 2

Jacqueline P. Duncan; Cornelis H. Pameijer

1998-01-01

170

Influence of fatigue testing and cementation mode on the load-bearing capability of bovine incisors restored with crowns and zirconium dioxide posts.  

PubMed

The aim of the study was to evaluate the influence of fatigue and cementation mode on the fracture behavior of endodontically treated bovine incisors restored with zirconium dioxide posts and crowns. Forty-eight endodontically treated bovine primary incisors were restored with zirconium dioxide posts (Cerapost, Brasseler), composite build-ups, and crowns cast from a chromium cobalt alloy. In 16 teeth, each of the posts was cemented conventionally with KetacCem (3M ESPE) or adhesively with Panavia F (Kuraray) or RelyX UniCem (3M ESPE). One-half of the specimens in each group were subjected to thermocycling with 10,000 cycles at 5-55 degrees C and mechanical aging, loading the specimens at an angle of 45 degrees in 1,200,000 cycles with 50 N. Fracture resistance was determined by loading the specimens until fracture at an angle of 45 degrees to the long axis of the teeth. The loading test showed that neither cementation mode nor fatigue testing had an influence on the load bearing capability. Most specimens fractured in a favorable way, independent from the type of cementation. PMID:18536945

Nothdurft, F P; Schmitt, T; Motter, P J; Pospiech, P R

2008-06-07

171

Polyester Resin Hazards  

PubMed Central

Polyester resins are being increasingly used in industry. These resins require the addition of catalysts and accelerators. The handling of polyester resin system materials may give rise to skin irritations, allergic reactions, and burns. The burns are probably due to styrene and organic peroxides. Atmospheric pollution from styrene and explosion and fire risks from organic peroxides must be prevented. Where dimethylaniline is used scrupulous cleanliness and no-touch technique must be enforced. Handling precautions are suggested. Images

Bourne, L. B.; Milner, F. J. M.

1963-01-01

172

Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation  

Microsoft Academic Search

Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive alternative option. This paper reports the development of photochemical mineralization process for organic ion-exchange resins of poly (styrene-divinyl benzene) type with sulfonic acid and quaternary ammonium functional

C. Srinivas; S. Sugilal; P. K. Wattal

2003-01-01

173

In vitro and in vivo studies on the toxicity of dental resin components: a review  

Microsoft Academic Search

In vitro and in vivo studies have clearly identified that some components of restorative composite resins, adhesives, and\\u000a resin-modified glass ionomer cements are toxic. The mechanisms of cytotoxicity are related firstly to the short-term release\\u000a of free monomers occurring during the monomer–polymer conversion. Secondly, long-term release of leachable substances is generated\\u000a by erosion and degradation over time. In addition, ion

Michel Goldberg

2008-01-01

174

Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation  

SciTech Connect

Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive alternative option. This paper reports the development of photochemical mineralization process for organic ion-exchange resins of poly (styrene-divinyl benzene) type with sulfonic acid and quaternary ammonium functional groups. It is a two-step process consisting of dissolution (conversion of solid resin into water-soluble reaction products) and photo-Fenton mineralization of the dissolved resin. Cation and anion resin dissolution was effected by reaction of the resin with H2O2 at 50-60 C in the presence of ferrous/copper sulphate catalyst. Direct dissolution of mixed resin was not efficient. However, the cation resin portion in the mixed resin could be selectively dissolved without affecting the anion portion. The solid anion resin after separation from the cation resin solution could be dissolved. About 0.5 liters of 50% H2O2 was required for dissolution of one kg of wet resin. The reaction time was 4-5 hours. Dissolution experiments were conducted on up to 8 liters of wet resin. The second step, viz., photo-Fenton mineralization of the dissolved resin was effected at ambient temperature(25-35 C). Kinetic results of laboratory scale experiments in immersion type photo-reactor and pilot scale experiments in tubular flow photo-reactor were presented. These results clearly demonstrated the photo-Fenton mineralization of dissolved resin at ambient temperature with stoichiometric quantity of H2O2 as against 70-200% excess H2O2 requirement in chemical mineralization experiments under Fenton oxidation conditions at 90-95 C. Based on these studies, a treatment scheme was developed and presented in this paper.

Srinivas, C.; Sugilal, S.; Wattal, P. K.

2003-02-26

175

Root reinforcement with a resin-bonded preformed post  

Microsoft Academic Search

Purpose. This study evaluated the ability of resin-bonded posts to reinforce teeth that are structurally weak in the cervical area against fracture.Material and methods. Forty canine roots were endodontically treated and randomly distributed into four groups of 10. Parallel-sided preformed posts were cemented into the roots of these teeth after their crowns were removed. The cervical third of the canals

Daniel B. Mendoza; W. Stephan Eakle; Ernest A. Kahl; Robert Ho

1997-01-01

176

Effect of Provisional Cements on Shear Bond Strength of Porcelain Laminate Veneers  

PubMed Central

Objectives: The purpose of this study was to evaluate the effect of three provisional cements and two cleaning techniques on the final bond strength of porcelain laminate veneers. Methods: The occlusal third of the crowns of forty molar teeth were sectioned and embedded in autopolymerizing acrylic resin. Dentin surfaces were polished and specimens were randomly divided into four groups (n=10). Provisional restorations were fabricated and two provisional restorations were cemented onto each tooth. Restorations were fixed with one of three different provisional cements: eugenol-free provisional cement (Cavex), calcium hydroxide (Dycal), and light-cured provisional cement (Tempond Clear). Provisional restorations were removed with either a dental explorer and air-water spray, or a cleaning bur (Opticlean). In the control group, provisional restorations were not used on the surfaces of specimens. IPS Empress 2 ceramic discs were luted with a dual-cured resin cement (Panavia F). Shear bond strength was measured using a universal testing machine. Data were statistically analyzed by ANOVA, Tukey’s HSD and Dunnett tests. Surfaces were examined by scanning electronic microscopy. Results: Significant differences were found between the control group and both the light-cured provisional cement groups and the eugenol-free provisional cement-cleaning bur group (P<.05). Groups that had received light-cured provisional cement showed the lowest bond strength values. Conclusions: Selection of the provisional cement is an important factor in the ultimate bond strength of the final restoration. Calcium hydroxide provisional cement and cleaning with a dental explorer are advisable.

Altintas, Subutay Han; Tak, Onjen; Secilmis, Asli; Usumez, Aslihan

2011-01-01

177

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

178

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

179

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

180

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

181

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

182

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

183

In vivo Dentin Microhardness beneath a Calcium-Phosphate Cement  

PubMed Central

A minimally invasive caries-removal technique preserves potentially repairable, caries-affected dentin. Mineral-releasing cements may promote remineralization of soft residual dentin. This study evaluated the in vivo remineralization capacity of resin-based calcium-phosphate cement (Ca-PO4) used for indirect pulp-capping. Permanent carious and sound teeth indicated for extraction were excavated and restored either with or without the Ca-PO4 base (control), followed by adhesive restoration. Study teeth were extracted after 3 months, followed by sectioning and in vitro microhardness analysis of the cavity floor to 115-µm depth. Caries-affected dentin that received acid conditioning prior to Ca-PO4 basing showed significantly increased Knoop hardness near the cavity floor. The non-etched group presented results similar to those of the non-treated group. Acid etching prior to cement application increased microhardness of residual dentin near the interface after 3 months in situ.

Bresciani, E.; Wagner, W.C.; Navarro, M.F.L.; Dickens, S.H.; Peters, M.C.

2010-01-01

184

Delayed cure bismaleimide resins  

DOEpatents

Prior art polybismaleimides begin to polymerize at or just above the melting point of the monomer. This patent describes new bismaleimide resins which have an increased pot life and provide longer time periods in which the monomer remains fluid. The resins can be polymerized into molded articles with a high uniformity of properties. (DLC)

Not Available

1982-08-12

185

Modified sulfur cement solidification of low-level wastes  

SciTech Connect

This topical report describes the results of an investigation on the solidification of low-level radioactive wastes in modified sulfur cement. The work was performed as part of the Waste Form Evaluation Program, sponsored by the US Department of Energy's Low-Level Waste Management Program. Modified sulfur cement is a thermoplastic material developed by the US Bureau of Mines. Processing of waste and binder was accomplished by means of both a single-screw extruder and a dual-action mixing vessel. Waste types selected for this study included those resulting from advanced volume reduction technologies (dry evaporator concentrate salts and incinerator ash) and those which remain problematic for solidification using contemporary agents (ion exchange resins). Process development studies were conducted to ascertain optimal process control parameters for successful solidification. Maximum waste loadings were determined for each waste type and method of processing. Property evaluation testing was carried out on laboratory scale specimens in order to compare with waste form performance for other potential matrix materials. Waste form property testing included compressive strength, water immersion, thermal cycling and radionuclide leachability. Recommended waste loadings of 40 wt. % sodium sulfate and boric acid salts and 43 wt. % incinerator ash, which are based on processing and performance considerations, are reported. Solidification efficiencies for these waste types represent significant improvements over those of hydraulic cements. Due to poor waste form performance, incorporation of ion exchange resin waste in modified sulfur cement is not recommended.

Not Available

1985-10-01

186

EP-toxicity testing of mercury removal resin grout  

SciTech Connect

To determine which category a waste will fit into, the EPA requires a classification test. The test, EP-toxicity, consists of a physical integrity test followed by an extraction. For the case of the mercury removal resin grout, the mercury concentration in the extract cannot exceed 0.2 mg/L if the waste is to be classified as ``solid waste.`` Otherwise, the waste is classified as ``hazardous.`` Simulated process solutions were used to load the mercury removal resin. The resin was solidified with the addition of cement and water using a formulation based on grout formulations typically used to solidify power reactor ion exchange resins. Envirodyne Engineers of St. Louis, Missouri, an EPA sanctioned laboratory, performed the EP-toxicity test for the two samples. One sample was a blank which was made with unloaded resin. For the formulation tested, the EP-toxicity test results showed that the mercury removal resin grout does not fit into the ``hazardous waste`` category.

Mersman, K.E.

1984-07-18

187

Biomimetic Remineralization of Resin-bonded Acid-etched Dentin  

PubMed Central

Degradation of denuded collagen within adhesive resin-infiltrated dentin is a pertinent problem in dentin bonding. A biomimetic remineralization scheme that incorporates non-classic crystallization pathways of fluidic amorphous nanoprecursors and mesoscopic transformation has been successful in remineralizing resin-free, acid-etched dentin, with evidence of intrafibrillar and interfibrillar remineralization. This study tested the hypothesis that biomimetic remineralization provides a means for remineralizing incompletely infiltrated resin-dentin interfaces created by etch-and-rinse adhesives. The remineralization medium consists of a Portland cement/simulated body fluid that includes polyacrylic acid and polyvinylphosphonic acid biomimetic analogs for amorphous calcium phosphate dimension regulation and collagen targeting. Both interfibrillar and intrafibrillar apatites became readily discernible within the hybrid layers after 2-4 months. In addition, intra-resin apatite clusters were deposited within the porosities of the adhesive resin matrices. The biomimetic remineralization scheme provides a proof-of-concept for the adoption of nanotechnology as an alternative strategy to extend the longevity of resin-dentin bonds.

Tay, F.R.; Pashley, D.H.

2009-01-01

188

The interaction between lining materials and composite resin restorative materials.  

PubMed

The effects of four lining materials, Dycal, Procal, Cavitec and Poly F cement on Adaptic and Concise have been investigated in vitro. The parameters studied were surface roughness, hardness and colour both with and without an intermediate (or bonding) resin being present between the restorative material and the liner. The effects of the four liners on the composites varied both between the lining materials themselves and with the composite resin. Two materials, Procal and Dycal, had little interaction with the composites, provided an intermediate resin was used with the latter. Cavitec appeared to have an adverse reaction with the composites and Poly F, whilst having no effect on the colour of the composites, did increase surface roughness. The adverse effects of linig materials were ascribed to minor constituents, particularly methyl salicylate, present in the formulation. PMID:6453213

Lingard, G L; Davies, E H; Von Fraunhofer, J A

1981-03-01

189

Distribution Coefficients (Kd Values) for Waste Resins Generated from the K and L Disassembly Basin Facilities  

SciTech Connect

The objective of this study was to measure 14C, 129I, and 99Tc Kd values of spent resin generated from the K and L Disassembly Basin Facilities. The scope of the work was to conduct Kd measurements of resins combined in the ratio that they are disposed, 42:58 cation:anion. Because it was not known how these spent resins would be buried, it was necessary to measure the Kd values in such a manner as to simulate both trench and vault disposal. This was accomplished by using an acid-rain simulant (a standard U.S. Environmental Protection Agency protocol) and a cement leachate simulant .

Kaplan, D.I.

2002-12-02

190

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

191

Construction, Testing and Performance Report on the Resin Modified Pavement Demonstration Project.  

National Technical Information Service (NTIS)

Resin Modified Pavement (RMP) is a composite paving material consisting of a thin layer (2 inches) of open graded hot mix asphalt (HMA) whose internal air voids (approximately 30% voids) are filled with a latex rubber-modified portland cement grout. The o...

J. S. Whittington R. L. Battey

2007-01-01

192

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

193

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

194

Summary of: Pulpotomy of human primary molars with MTA and Portland cement: a randomised controlled trial  

Microsoft Academic Search

Objective This study compared the clinical and radiographic effectiveness of mineral trioxide aggregate (MTA) and Portland cement (PC) as pulp dressing agents in carious primary teeth.Methodology Thirty carious primary mandibular molars of children aged 5-9 years old were randomly assigned to MTA or PC groups, and treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass

M. Duggal

2009-01-01

195

Pulpotomy of human primary molars with MTA and Portland cement: a randomised controlled trial  

Microsoft Academic Search

Objective This study compared the clinical and radiographic effectiveness of mineral trioxide aggregate (MTA) and Portland cement (PC) as pulp dressing agents in carious primary teeth.Methodology Thirty carious primary mandibular molars of children aged 5-9 years old were randomly assigned to MTA or PC groups, and treated by a conventional pulpotomy technique. The teeth were restored with resin modified glass

A. B. S. Moretti; T. M. Oliveira; A. P. C. Fornetti; C. F. Santos; M. A. A. M. Machado; R. C. C. Abdo; V. T. Sakai

2009-01-01

196

21 CFR 888.3540 - Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2013 CFR

...5833:1992 âImplants for SurgeryâAcrylic Resin Cements...5834-2:1998 âImplants for SurgeryâUltra-high Molecular Weight...7207-2:1998 âImplants for SurgeryâComponents for Partial and...Made of Metal, Ceramic and Plastic Materials,â and...

2013-04-01

197

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

198

Dilatometry on Thermoset Resins.  

National Technical Information Service (NTIS)

A simple capillary and bulb mercury dilatometer designed for making specific volume measurements on thermoset resin systems during the curing reaction and as a function of temperature is described. The design, calibration, operation, data treatment and er...

A. W. Snow J. P. Armistead

1991-01-01

199

Thermally Stable Laminating Resins.  

National Technical Information Service (NTIS)

Improved thermally stable laminating resins were developed based on the addition-type pyrolytic polymerization. Detailed monomer and polymer synthesis and characterization studies identified formulations which facilitate press molding processing and autoc...

E. A. Burns R. J. Jones R. W. Vaughan

1972-01-01

200

Bond Strength of Composite Resin to Pulp Capping Biomaterials after Application of Three Different Bonding Systems  

PubMed Central

Background and aims. Bonding of composite resin filling materials to pulp protecting agents produces an adhesive joint which is important for the quality of filling as well as success of restoration. We aimed to assess the bond strength of composite resin to three pulp capping biomaterials: Pro Root mineral trioxide aggregate (PMTA), Root MTA (RMTA) and calcium enriched mixture (CEM) cement, using three bonding systems [a total-etch (Single Bond) and two self-etch systems (Protect bond and SE Bond)]. Materials and methods. Ninety acrylic molds, each containing a 6×2-mm hole, were divided into 3 groups and filled with PMTA, RMTA and CEM cements. The samples in each experimental group were then randomly divided into 3 sub-groups; Single Bond, Protect Bond and SE Bond bonding systems were applied to the tested materials. Cylindrical forms of composite resin (Z100, 2×2 mm) were placed onto the samples and cured. Shear bond strength values were measured for 9 subgroups using a universal testing machine. Data were analyzed using two-way ANOVA. Results. The average shear bond strengths of Z100 composite resin after application of Single Bond, Protect Bond and SE Bond systems were as follows; PMTA: 5.1±2.42, 4.56±1.96 and 4.52±1.7; RMTA: 4.71±1.77, 4.31±0.56 and 4.79±1.88; and CEM cement: 4.75±1.1, 4.54±1.59 and 4.64±1.78 MPa, respectively. The type of pulp capping material, bonding system and their interacting effects did not have a significant effect on the bond strengths of composite resin to pulp capping biomaterials. Conclusion. Within the limitations of this in vitrostudy, bond strength of composite resin to two types of MTA as well as CEM cement were similar following application of the total-etch or self-etch bonding systems.

Jaberi-Ansari, Zahra; Mahdilou, Maryam; Ahmadyar, Maryam; Asgary, Saeed

2013-01-01

201

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

202

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

203

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

204

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

205

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

206

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

207

Performance testing of grout-based waste forms for the solidification of anion exchange resins  

SciTech Connect

The solidification of spent ion exchanges resins in a grout matrix as a means of disposing of spent organic resins produced in the nuclear fuel cycle has many advantages in terms of process simplicity and economy, but associated with the process is the potential for water/cement/resins to interact and degrade the integrity of the waste form solidified. Described in this paper is one possible solution to preserving the integrity of these solidified waste forms: the encapsulation of beaded anion exchange resins in grout formulations containing ground granulated blast furnace slag, Type I-II (mixed) portland cement, and additives (clays, amorphous silica, silica fume, and fly ash). The results of the study reported herein show the cured waste form tested has a low leach rate for nitrate ion from the resin (and a low leach rate is inferred for Tc-99) and acceptable durability as assessed by the water immersion and freezing/thawing test protocols. The results also suggest a tested surrogate waste form prepared in vinyl ester styrene binder performs satisfactorily against the wetting/drying criterion, and it should offer additional insight into future work on the solidification of spent organic resins. 26 refs., 4 figs., 5 tabs.

Morgan, I.L.; Bostick, W.D.

1990-10-01

208

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

209

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

210

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

211

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

212

Method for removing contaminants from plastic resin  

DOEpatents

A resin recycling method that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The method includes receiving the resin in container form. The containers are then ground into resin particles. The particles are exposed to a solvent, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. After separating the particles and the resin, a solvent removing agent is used to remove any residual solvent remaining on the resin particles after separation.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee' s Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2008-12-09

213

Phosphonic acid based exchange resins  

DOEpatents

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1995-01-01

214

Production of petroleum polymer resins  

Microsoft Academic Search

In other countries, petroleum polymer resins are being used successfully in large volumes. In the U.S. in 1982, for example, 128,000 tonnes of petroleum polymer resins were produced [2], much of which was used in the paint and varnish industry. In commercial production in the USSR are a dark-colored styrene-lndene resin and light-colored petroleum polymer resins of two types --

Yu. V. Dumskii; M. E. Belyakov; A. K. Suroto; G. F. Cherednikova; L. B. Grin'ko

1988-01-01

215

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

216

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

217

Powdered resin for condensate polishing  

Microsoft Academic Search

Powdered resin systems have a lot to offer in the deionization of low TDS waters, as can be seen in the wide use of this process for the treatment of condensate in the electric power industry. I believe that as new ion-exchange resins are developed, we will see the powdered ion-exchange resin process adopted in other industries. At this time,

Richard Hetherington

1997-01-01

218

Epoxy resin sand consolidation rejuvenation  

Microsoft Academic Search

A process is described for increasing the strength and stability of an epoxy resin-consolidated permeable mass of grains that has been weakened by a resin- degradative aqueous liquid. The mud acids, which comprise aqueous solutions of acidic materials that contain (or form) hydrofluoric acid, are particularly strong resin-degradative aqueous liquids. A consolidated permeable mass of grains that contains an epoxy

T. W. Jr. Hamby; W. T. Jr. Strickland

1972-01-01

219

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

220

Dental composite resins: measuring the polymerization shrinkage using optical fiber Bragg grating sensors  

NASA Astrophysics Data System (ADS)

Polymerization shrinkage of dental composite materials is recognized as one of the main reasons for the development of marginal leakage between a tooth and filling material. As an alternative to conventional measurement methods, we propose optical fiber Bragg grating (FBG) based sensors to perform real-time strain and shrinkage measurements during the curing process of dental resin cements. We introduce a fully automated set-up to measure the Bragg wavelength shift of the FBG strain sensors and to accurately monitor the linear strain and shrinkage of dental resins during curing. Three different dental resin materials were studied in this work: matrix-filled BisGMA-based resins, glass ionomers and organic modified ceramics.

Ottevaere, H.; Tabak, M.; Chah, K.; Mégret, P.; Thienpont, H.

2012-05-01

221

CTBN Modified Epoxy Resin.  

National Technical Information Service (NTIS)

An encapsulating resin for electronic components is evaluated for critical parameters. The encapsulant studied is a CTBN/Epoxy/DEA system. Several curatives were evaluated for use with the system, as were the effect of an antioxidant. Compared with a more...

K. E. Creed

1975-01-01

222

Resin composite contours.  

PubMed

When placing posterior composite resin restorations, clinicians often struggle to achieve good contacts. Frequently contacts that are successful are only confined to the occlusal aspect of the proximal wall. A clinical technique is discussed which achieves the correct contour as well as tight contacts. The technique is also minimally invasive and highly aesthetic. PMID:20448605

Sidelsky, H

2010-05-01

223

Waiting Time for Coronal Preparation and the Influence of Different Cements on Tensile Strength of Metal Posts  

PubMed Central

This study aimed to assess the effect of post-cementation waiting time for core preparation of cemented cast posts and cores had on retention in the root canal, using two different luting materials. Sixty extracted human canines were sectioned 16?mm from the root apex. After cast nickel-chromium metal posts and cores were fabricated and luted with zinc phosphate (ZP) cement or resin cement (RC), the specimens were divided into 3 groups (n = 10) according to the waiting time for core preparation: no preparation (control), 15 minutes, or 1 week after the core cementation. At the appropriate time, the specimens were subjected to a tensile load test (0.5?mm/min) until failure. Two-way ANOVA (time versus cement) and the Tukey tests (P < 0.05) showed significantly higher (P < 0.05) tensile strength values for the ZP cement groups than for the RC groups. Core preparation and post-cementation waiting time for core recontouring did not influence the retention strength. ZP was the best material for intraradicular metal post cementation.

Oliveira, Ilione Kruschewsky Costa Sousa; Arsati, Ynara Bosco de Oliveira Lima; Basting, Roberta Tarkany; Franca, Fabiana Mantovani Gomes

2012-01-01

224

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

225

Fatigue resistance of teeth restored with fiber posts and different post cementation strengths.  

PubMed

This study sought to evaluate how different post cementation strategies affected the fatigue resistance of bovine teeth restored with glass fiber posts. The canals of 63 single-rooted bovine teeth (each 16 mm in length) were prepared to 9 mm using a preparation drill from a double-tapered fiber post system. Each specimen was embedded in a PVC cylinder using acrylic resin up to 3 mm of the most coronal portion of the specimen and was allocated into one of seven groups (n = 9) based on the strategies for cementation. After cementation, a standard core build-up was made with composite resin. The specimens were stored for seven days and submitted to mechanical cycling (50 N, 8 Hz, 37 degrees C). After fatigue testing, a score was given to each specimen, based on the number of fatigue cycles required to fracture the specimens; the scores were submitted to statistic analysis (Kruskal-Wallis, alpha = 0.05). The strategy for post cementation did not affect the resistance to fatigue (P = 0.8669). Based on the results, the resistance to fatigue does not appear to depend on the post cementation strategy. PMID:19819817

Valandro, Luiz Felipe; Zardin, Lucas Wadas; de Villa, Marco Antonio; Amaral, Marina; Galhano, Graziela; Baldissara, Paolo; Bottino, Marco Antonio

226

High elastic modulus nanopowder reinforced resin composites for dental applications  

NASA Astrophysics Data System (ADS)

Dental restorations account for more than $3 billion dollars a year on the market. Among them, all-ceramic dental crowns draw more and more attention and their popularity has risen because of their superior aesthetics and biocompatibility. However, their relatively high failure rate and labor-intensive fabrication procedure still limit their application. In this thesis, a new family of high elastic modulus nanopowder reinforced resin composites and their mechanical properties are studied. Materials with higher elastic modulus, such as alumina and diamond, are used to replace the routine filler material, silica, in dental resin composites to achieve the desired properties. This class of composites is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Most of the work focuses on nano-sized Al2O3 (average particle size 47 nm) reinforcement in a polymeric matrix with 50:50 Bisphenol A glycidyl methacrylate (Bis-GMA): triethylene glycol dimethacrylate (TEGDMA) monomers. Surfactants, silanizing agents and primers are examined to obtain higher filler levels and enhance the bonding between filler and matrix. Silane agents work best. The elastic modulus of a 57.5 vol% alumina/resin composite is 31.5 GPa compared to current commercial resin composites with elastic modulus <15 GPa. Chemical additives can also effectively raise the hardness to as much as 1.34 GPa. Besides>alumina, diamond/resin composites are studied. An elastic modulus of about 45 GPa is obtained for a 57 vol% diamond/resin composite. Our results indicate that with a generally monodispersed nano-sized high modulus filler, relatively high elastic modulus resin-based composite cements are possible. Time-dependent behavior of our resin composites is also investigated. This is valuable for understanding the behavior of our material and possible fatigue testing in the future. Our results indicate that with effective coupling agents and higher filler loading, viscous flow can be greatly decreased due to the attenuation of mobility of polymer chains. Complementary studies indicate that our resin composites are promising for the proposed applications as a stiff support to all-ceramic crowns.

Wang, Yijun

227

Reliability of fiber post bonding to root canal dentin after simulated clinical function in vitro.  

PubMed

The aim of this study was to investigate the effect of thermomechanical loading (TML) on the bond strength of fiber posts luted with three different resin cements. Sixty-six extracted human anterior teeth were endodontically treated and restored with fiber posts (RelyX Fiber Posts, 3M ESPE) using three commercially available resin cements and three corresponding core build-up materials (n=22 each): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), and RelyX Unicem/Filtek Z250 (3M ESPE). Twelve specimens of each group received all-ceramic crowns and were subjected to TML. The other 10 specimens were stored in saline solution for 24 hours. The roots were sectioned and bond strength was measured using a push-out test. Adhesive interfaces of two specimens of each group subjected to TML were analyzed using field emission scanning electron microscopy (FESEM). Bond strengths of fiber posts were significantly affected by the type of resin cement (p<0.0005) and TML (p<0.0005; two-way analysis of variance). TML significantly reduced bond strengths for all materials ((6.0 (6.2) MPa)) compared with initial bond strengths ((14.9 (10.4) MPa)). RelyX Unicem resulted in significantly higher bond strengths before ((18.3 (10.3) MPa)) and after TML ((9.8 (7.5) MPa)) compared with the other materials (p<0.0005; Tukey HSD). Using FESEM, Variolink II and Panavia F demonstrated a hybrid layer partly detached from the underlying resin cement, whereas no hybrid layer was observed for RelyX Unicem. The decrease in bond strength after TML suggests that retention of fiber posts may be reduced after clinical function. Therefore, endodontically treated teeth that are restored using fiber posts may benefit from additional reinforcement via coronal restorations using adequate ferrules and/or adhesive techniques. PMID:22339386

Bitter, K; Perdigão, J; Exner, M; Neumann, K; Kielbassa, Am; Sterzenbach, G

2012-02-16

228

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

229

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

230

Resin composite restorative materials.  

PubMed

This paper surveys the most important developments in resin-based dental composites and focuses on the deficits (e.g. polymerization shrinkage) and strengths of the materials and their clinical implications. Moreover, differences between composite categories, such as hybrid, nanohybrid, microfilled, packable, ormocer-based, silorane-based, polyacid-modified composites (compomers) and flowable composites are highlighted, especially in view of their mechanical behaviour. In addition to the classical dimethacrylate-based composites, special attention is given to alternative monomers, such as siloranes, ormocers or high-molecular-weight dimethacrylate monomers (e.g. dimer acid-based dimethacrylates and tricyclodecane (TCD)-urethane), analysing their advantages, behaviour and abilities. Finally, the paper attempts to establish the needs and wishes of clinicians for further development of resin-based composites. PMID:21564116

Ilie, N; Hickel, R

2011-06-01

231

[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

232

System for removing contaminants from plastic resin  

DOEpatents

A resin recycling system that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The system includes receiving the resin in container form. A grinder grinds the containers into resin particles. The particles are exposed to a solvent in one or more solvent wash vessels, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. A separator is used to separate the resin particles and the solvent. The resin particles are then placed in solvent removing element where they are exposed to a solvent removing agent which removes any residual solvent remaining on the resin particles after separation.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee' s Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2010-11-23

233

Adherence of resin-based luting agents assessed by the energy of fracture.  

PubMed

The present study assessed the adherence of nine commercial resin cements by means of the wedge test. The beams of the test were made of a Ni-Cr-Be alloy, and the adhering surfaces were sandblasted with 250 microns Al2O3. The energy of fracture of the investigated cements varied from less than 10 J/m2 to 121 J/m2. The fracture energies were not influenced by 1) the thickness of the joint, 2) the width of the beams, 3) the use of an intermediary noncomposite resin, or 4) storage in water beyond 24 h. In spite of a rather high variability within groups, it is concluded that the wedge test may give relevant data on the performance of adhesive joints. PMID:8237307

Asmussen, E; Attal, J P; Degrange, M

1993-08-01

234

In vitro caries inhibition by polyacid-modified composite resins (‘compomers’)  

Microsoft Academic Search

Objectives: The aim of this study was to compare the in-vitro caries inhibition of two polyacid-modified composite resins (PMCRs).Methods: Three standardized class V cavities were prepared in eight extracted human molar teeth. Two of these cavities in each tooth were restored with Compoglass and Dyract according to manufacturers' guidelines. A conventional glass-ionomer cement restoration (Chemfil II) was placed in the

B. J. Millar; F. Abider; J. W. Nicholson

1998-01-01

235

Immediate resin-bonded bridgework: results of a medium-term clinical follow-up study.  

PubMed

A total of 21 immediate resin-bonded bridges were inserted under controlled and standardized clinical conditions and evaluated over a period of 35 months. During the evaluation period, two bridges debonded (9.5%). The debonded bridges were re-cemented successfully. This low incidence of debonding indicates that this simple alternative procedure for the immediate replacement of a single unsaveable tooth was satisfactory. The subjects included in this study expressed their satisfaction with this form of treatment. PMID:15125604

Al-Wahadni, A M; Al-Omari, W M

2004-01-01

236

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

237

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

238

Microleakage of adhesive resinous materials in root canals  

PubMed Central

Aim: The purpose of this study was to compare the in vitro micro-leakage resistance of adhesive resin materials to long-used zinc oxide-eugenol and epoxy resin sealers. Materials and Methods: Seven materials, five test (Real Seal, Real Seal XT, Panavia F 2.0, Infinity Syringeable, GCEM) and two controls (Tubliseal, AH Plus), were evaluated for micro-leakage resistance in a bovine incisor root model, with 12 roots per material. Teeth were root canal treated, stored in water, artificially aged by thermal-cycling, stained with silver nitrate, sectioned to yield eight measurement points per tooth (four coronal and four apical), giving 672 measurement points. Stain penetration was measured using digital positioners and a toolmakers microscope; then analyzed using descriptive statistics, two-way analysis of variance and multiple comparisons testing (P < 0.05). Results: All modern adhesive resinous materials leaked significantly less than long-used zinc oxide-eugenol and epoxy resin sealers (P < 0.05). Mean leakage values and their associated (standard deviations) in mm were: Infinity Syringeable 2.5 (1.5), Real Seal XT 3.2 (1.4), Real Seal 3.4 (1.6), Panavia F 2.0 3.8 (2.7), GCEM 4.2 (1.8), Tubli-seal 5.4 (2.8), AH Plus 6.3 (2.3). Overall, more leakage occurred apically than coronally (P < 0.0001). Many materials exhibited dimensional instability: Marked contraction, expansion, or lack of cohesion. Conclusion: A variety of adhesive resinous materials, endodontic sealers and crown cements, reduced micro-leakage in comparison to long and widely used zinc oxide- eugenol and epoxy sealers.

Wong, Jason Gilbert; Caputo, Angelo Anthony; Li, Ping; White, Shane Newport

2013-01-01

239

Indirect resin composites  

PubMed Central

Aesthetic dentistry continues to evolve through innovations in bonding agents, restorative materials, and conservative preparation techniques. The use of direct composite restoration in posterior teeth is limited to relatively small cavities due to polymerization stresses. Indirect composites offer an esthetic alternative to ceramics for posterior teeth. This review article focuses on the material aspect of the newer generation of composites. This review was based on a PubMed database search which we limited to peer-reviewed articles in English that were published between 1990 and 2010 in dental journals. The key words used were ‘indirect resin composites,’ composite inlays,’ and ‘fiber-reinforced composites.’

Nandini, Suresh

2010-01-01

240

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

241

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

242

A study of wet catalytic oxidation of radioactive spent ion exchange resin by hydrogen peroxide  

SciTech Connect

The decomposition behavior of cationic, anionic, and mixed ion-exchange resins was investigated in the H{sub 2}O{sub 2}-Ni{sup 2+}/Cu{sup 2+}, H{sub 2}O{sub 2}-Mn{sup 2+}/Cu{sup 2+}, H{sub 2}O{sub 2}-Fe{sup 2+}, H{sub 2}O{sub 2}-Cu{sup 2+}, and H{sub 2}O{sub 2}-Fe{sup 2+}/Cu{sup 2+} systems for volume reduction and improvement in the capacity of the cemented product. The effects on reaction processes and the consequences of many other factors were analyzed. No radioactivity was detected in the off-gas. The cementation process of encapsulation of the concentrated decomposition residue could produce qualified cemented products with excellent properties for long-term storage in a volume-reduced state.

Xingchao Jian; Tianbao Wu; Guichun Yun [Tsinghua Univ., Beijing (China)

1996-04-01

243

Spot-welded wire hooks as seating guides for resin-bonded castings.  

PubMed

A technique is described to assist in accurate positioning of cast metal, resin-bonded prostheses. The method is particularly useful for the recementation of castings but can also be used with new restorations. A piece of rectangular chrome alloy arch wire is annealed and spot-welded to the retainer. The wire is then adapted to lie over the incisal edge of the abutment tooth and forms a locating device during trying in and cementing of the restoration. The wire hook assists in the handling of the casting at chairside and is easily snapped off after cementation, leaving little finishing to be completed. The technique permits access to all of the marginal surfaces at cementation and offers certain advantages over existing alternative techniques. PMID:1686465

Millar, B; Nesbit, M

1991-10-01

244

Validation of the small-punch test as a technique for characterizing the mechanical properties of acrylic bone cement.  

PubMed

This paper examines the validity of using the small-punch test technique as a means of quantifying the mechanical properties of acrylic bone cement under different test conditions. The elastic moduli calculated using the small-punch test method were compared with data measured using the international standard for acrylic bone resin, ISO 5833. Conclusions from the study indicate that the small-punch test is a reproducible miniature specimen test method that can be used to characterize the mechanical properties of retrieved acrylic bone cement as used in total joint replacement surgery. Moreover, the test conditions were found to influence the elastic modulus of acrylic bone cement. The test temperature had a greater effect on the elastic behaviour of the bone cement than the test medium. PMID:16459442

Dunne, N J; Leonard, D; Daly, C; Buchanan, F J; Orr, J F

2006-01-01

245

ELUTION OF URANIUM FROM RESIN  

Microsoft Academic Search

A method is described for eluting uranium from anion exchange resins so ; as to decrease vanadium and iron contamination and permit recycle of the major ; portion of the eluats after recovery of the uranium. Diminution of vanadium and ; iron contamination of the major portion of the uranium is accomplished by ; treating the anion exchange resin, which

1959-01-01

246

Mechanical Retention of Resin Veneers.  

National Technical Information Service (NTIS)

Mechanical retention of resin veneers is provided for by a number of means, including the use of retentive beads. Studies have been reported in which resin-gold bonds were evaluated using beads, but no known effort had been made to determine the number be...

J. W. O'Hara W. G. Richardson R. J. Leupold G. B. Pelleu

1974-01-01

247

Water Damage in Polyester Resins  

Microsoft Academic Search

The nature of cracks, produced in three cured polyester resins during exposure to water has been studied by the combined techniques of optical microscopy, scanning electron microscopy and electron probe X-ray microanalysis. There are many cracks totally enclosed within the resin and it is shown that these must be attributed to pockets of high pressure produced at impurity inclusions by

K. H. G. Ashbee; F. C. Frank; R. C. Wyatt

1967-01-01

248

Phosphorous-Containing Imide Resins.  

National Technical Information Service (NTIS)

Flame-resistant reinforced bodies are disclosed which are composed of reinforcing fibers, filaments or fabrics in a cured body of bis- and tris-imide resins. These resins are derived from tris(m-aminophenyl) phosphine oxides by reaction with maleic anhydr...

I. K. Varma G. M. Fohlen J. A. Parker

1983-01-01

249

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

250

Tensile strength of thin resin composite layers as a function of layer thickness.  

PubMed

As a rule, cast restorations do not allow for free curing contraction of the resin composite luting cement. In a rigid situation, the resulting contraction stress is inversely proportional to the resin layer thickness. Adhesive technology has demonstrated, however, that thin joints may be considerably stronger than thicker ones. To investigate the effects of layer thickness and contraction stress on the tensile strength of resin composite joints, we cured cylindrical samples of a chemically initiated resin composite (Clearfil F2) in restrained conditions and subsequently loaded them in tension. The samples had a diameter of 5.35 mm and thicknesses of 50, 100, 200, 300, 400, 500, 600, and 700 microns, 1.4 mm, or 2.7 mm. None of the samples fractured due to contraction stress prior to tensile loading. Tensile strength decreased gradually from 62 +/- 2 MPa for the 50-microns layer to 31 +/- 4 MPa for the 2.7-mm layer. The failures were exclusively cohesive in resin for layers between 50 and 400 microns thick. Between 500 and 700 microns, the failures were cohesive or mixed adhesive/cohesive, while the 1.4- and 2.7-mm layers always failed in a mixed adhesive/cohesive mode. For the resin composite tested, the contraction stress did not endanger the cohesive strength. It was concluded that if adhesion to tooth structure were improved, thinner adhesive joints might enhance the clinical success of luted restorations. PMID:8530735

Alster, D; Feilzer, A J; De Gee, A J; Davidson, C L

1995-11-01

251

Antibacterial properties of amalgam and composite resin materials used as cores under crowns.  

PubMed

The Aim of this Study was to compare the bacterial growth in the bulk of both amalgam and fluoridated composite resin materials used as cores under crowns at core's surface (in the superficial area of the bulk) and depth levels. With 24 lower premolars, 12 of them were restored with metal posts and amalgam cores (group 1). The rest were restored with glass Fiber-reinforced Composite (FRC) posts and fluoridated composite resin cores (group 2). All specimens were covered with aluminium crowns cemented with resin cement, and then they were soaked in natural saliva for three months. Excoriations abraded from the superficial and the depth areas of the core materials were cultured under aerobic conditions on blood agar plates. After incubation for 2 days, colonies formed on the plates were identified, and the CFU mg(-1) counts were recorded accordingly. Statistical analysis was performed using an independent sample T test. The mean values of CFU mg(-1) counts in group 2 excoriations (surface 39.75, and depth 9.75) were higher than the group 1 excoriations (surface 1.67, and depth 0.42). This study supports the use of amalgam for building up cores due to its antibacterial properties. Composite resin, however, enhanced sizable bacterial growth despite the presence of fluoride. PMID:22852523

Al Ghadban, A; Al Shaarani, F

2012-06-01

252

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

253

Moisture-tolerant resin-based sealant: A boon  

PubMed Central

Background and Objectives: Pit and fissure sealants are highly effective in preventing occlusal caries. The present study clinically evaluated and compared the retention and development of caries when sealed with moisture-tolerant resin-based sealant, conventional resin-based sealant with and without a bonding agent, and Glass Ionomer Cement Sealant in young permanent teeth. Materials and Methods: A total of 80 healthy cooperative children aged 6-9 years who were at high caries risk with all four newly erupted permanent first molars were included in the study. Teeth were divided into 4 groups using a full-factorial design, and each of the molars was sealed with the four different sealant material. Evaluation of sealant retention and development of caries was performed at 6 and 12 months using Modified Simonsen's criteria. The data obtained were tabulated and subjected to statistical analysis using Kruskal-Wallis Test and Mann-Whitney Test. Result and Conclusion: The result from the present study indicated that moisture-tolerant resin-based sealant could be successfully used as a pit and fissure sealant because its hydrophilic chemistry makes it less technique sensitive and simplifies the sealant application procedure.

Bhat, Prasanna Kumar; Konde, Sapna; Raj, Sunil N.; Kumar, Narayan Chandra

2013-01-01

254

Influence of abutment material and luting cements color on the final color of all ceramics.  

PubMed

Abstract Purpose. The purpose of this study is to evaluate the effects of different abutment materials and luting cements color on the final color of implant-supported all-ceramic restorations. Materials and methods. Ten A2 shade IPS e.max Press disc shape all-ceramic specimens were prepared (11 × 1.5 mm). Three different shades (translucent, universal and white opaque) of disc shape luting cement specimens were prepared (11 × 0.2 mm). Three different (zirconium, gold-palladium and titanium) implant abutments and one composite resin disc shape background specimen were prepared at 11 mm diameter and appropriate thicknesses. All ceramic specimens colors were measured with each background and luting cement samples on a teflon mold. A digital spectrophotometer used for measurements and data recorded as CIE L*a*b* color co-ordinates. An optical fluid applied on to the samples to provide a good optical connection and measurements on the composite resin background was saved as the control group. ?E values were calculated from the ?L, ?a and ?b values between control and test groups and data were analyzed with one-way variance analysis (ANOVA) and mean values were compared by the Tukey HSD test (? = 0.05). Results. One-way ANOVA of ?L, ?a, ?b and ?E values of control and test groups revealed significant differences for backgrounds and seldom for cement color groups (p the 0.05). Only zirconium implant abutment groups and gold palladium abutment with universal shade cement group were found to be clinically acceptable (?E ? 3.0). Conclusion. Using titanium or gold-palladium abutments for implant supported all ceramics will be esthetically questionable and white opaque cement will be helpful to mask the dark color of titanium abutment. PMID:23627846

Dede, Dogu Ömür; Armaganci, Arzu; Ceylan, Gözlem; Cankaya, Soner; Cel?k, Ersan

2013-04-29

255

Prospective clinical trial of polyethylene fiber ribbon-reinforced, resin composite post-core buildup restorations.  

PubMed

The aim of this prospective clinical trial was to determine the outcome of polyethylene fiber ribbon-reinforced, resin composite post-and-core restorations used as endodontic buildups to support all-ceramic crowns. A total of 42 teeth (31 anterior, 11 posterior) with a mean follow-up time of 35.85 months (range, 10 to 73 months) were treated with 3-mm-wide polyethylene fiber ribbon-reinforced resin composite as post-and-core material. The posts and cores were assessed by clinical and radiographic examination. During the evaluation period, only 1 dentin-cement failure was observed as a post dislodgement after 11 months of clinical service. Performance of polyethylene fiber ribbon post and resin composite core foundation restorations provided clinically satisfactory support for all-ceramic crowns. PMID:17319364

Turker, Sebnem Begum; Alkumru, Hasan N; Evren, Buket

256

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

257

Chemical adhesion rather than mechanical retention enhances resin bond durability of a dental glass-ceramic with leucite crystallites.  

PubMed

This study aims to evaluate the effect of chemical adhesion by a silane coupler and mechanical retention by hydrofluoric acid (HFA) etching on the bond durability of resin to a dental glass ceramic with leucite crystallites. Half of the ceramic plates were etched with 4.8% HFA (HFA group) for 60 s, and the other half were not treated (NoHFA group). The scale of their surface roughness and rough area was measured by a 3D laser scanning microscope. These plates then received one of the following two bond procedures to form four bond test groups: HFA/cement, NoHFA/cement, HFA/silane/cement and NoHFA/silane/cement. The associated micro-shear bond strength and bond failure modes were tested after 0 and 30 000 thermal water bath cycles. Four different silane/cement systems (Monobond S/Variolink II, GC Ceramic Primer/Linkmax HV, Clearfil Ceramic Primer/Clearfil Esthetic Cement and Porcelain Liner M/SuperBond C&B) were used. The data for each silane/cement system were analyzed by three-way ANOVA. HFA treatment significantly increased the surface R(a) and R(y) values and the rough area of the ceramic plates compared with NoHFA treatment. After 30 000 thermal water bath cycles, the bond strength of all the test groups except the HFA/Linkmax HV group was significantly reduced, while the HFA/Linkmax HV group showed only adhesive interface failure. The other HFA/cement groups and all NoHFA/cement groups lost bond strength completely, and all NoHFA/silane/cement groups with chemical adhesion had significantly higher bond strength and more ceramic cohesive failures than the respective HFA/cement groups with mechanical retention. The result of the HFA/silane/cement groups with both chemical adhesion and mechanical retention revealed that HFA treatment could enhance the bond durability of resin/silanized glass ceramics, which might result from the increase of the chemical adhesion area on the ceramic rough surface and subsequently reduced degradation speed of the silane coupler, rather than the mechanical retention of the ceramic rough surface. PMID:20683131

Meng, X F; Yoshida, K; Gu, N

2010-08-03

258

Bonding of adhesive resin luting agents to metal and amalgam.  

PubMed

The shear bond strength of three adhesives, Panavia 21, Superbond, All Bond C&B Cement, and a dual cure resin (Variolink), to Ni-Cr-Be (Rexillium III), Midigold (Type III gold) and Amalgam (Sybraloy) were determined. Fifteen samples were prepared using 800 grit abrasive papers for Ni-Cr and Midi-Gold, and 100 grit papers for amalgam. Ni-Cr-Be and Midi-Gold samples were sandblasted for 30 s and steam cleaned for 10 s. The adhesives were bonded to the samples using gelatine capsules and were matured for 24 h in water at 37 degrees C. The samples were debonded in shear using an Instron at a cross-head speed of 1 mm/min. The data was analysed using ANOVA and a Tukey test. The bond strength of Superbond to both metal alloys was significantly higher (P<0.05) than any of the materials tested, with the exception Panavia 21 to gold. The bond strength of All Bond C&B cement had shown to be not significant difference from those of Panavia 21 and Variolink, when bonded to Rexillium and Midi-Gold, respectively. The bond strength of All Bond C&B Cement to amalgam was significantly greater (P<0.05) than those of the other materials tested. The shear bond strength to gold showed lower bonding for all adhesives when compared with Rexillium (P<.001). The ranking of bond strength to both alloys was as follows: Superbond>Panavia 21>All Bond C&B>Variolink. The nature of substrate to be used for bonding and the adhesive material itself are important factors in bonding which can be achieved between cast metals and prepared teeth with amalgam filling. Superbond should be successful as an adhesive for the attachment of all substrates tested, with the possible exception of amalgam, for which All Bond C&B Cement gives the best result. PMID:19177728

Osman, Saad A; McCabe, John F; Walls, Angus W G

2008-12-01

259

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorus. The pendent groups have the formula as shown in the patent wherein R is hydrogen, a cation or mixtures thereof; and R{sup 1} is hydrogen or an C{sub 1}-C{sub 2} alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

Trochimcznk, A.W.; Gatrone, R.C.; Alexandratos, S.; Horwitz, E.P.

1997-04-08

260

The Ability of Portland Cement, MTA, and MTA Bio to Prevent Through-and-Through Fluid Movement in Repaired Furcal Perforations  

Microsoft Academic Search

This study assessed the ability of Portland cement, white Angelus-mineral trioxide aggregate (MTA), and MTA Bio to seal furcal perforations in extracted human molar teeth. Fifty-five human mandibular molar teeth were accessed, and the canal orifices were located. The roots were horizontally sectioned in the middle third. Resin composite was used to fill the root canal orifices and the apical

Gustavo De-Deus; Claudia Reis; Claudia Brandão; Sandra Fidel; Rivail Antonio; Sergio Fidel

261

The Ability of Portland Cement, MTA, and MTA Bio to Prevent Through-and-Through Fluid Movement in Repaired Furcal Perforations  

Microsoft Academic Search

This study assessed the ability of Portland cement, white Angelus–mineral trioxide aggregate (MTA), and MTA Bio to seal furcal perforations in extracted human molar teeth. Fifty-five human mandibular molar teeth were accessed, and the canal orifices were located. The roots were horizontally sectioned in the middle third. Resin composite was used to fill the root canal orifices and the apical

Gustavo De-Deus; Claudia Reis; Claudia Brandão; Sandra Fidel; Rivail Antonio Sergio Fidel

2007-01-01

262

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

263

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

264

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

265

Synthesis of Improved Polyester Resins.  

National Technical Information Service (NTIS)

Eighteen aromatic unsaturated polyester prepolymers prepared by a modified interfacial condensation technique were investigated for their solubility in vinyl monomers and ability to provide high char yield forming unsaturated polyester resins. The best re...

A. H. McLeod C. B. Delano

1979-01-01

266

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

267

Resin composition having lubricating properties  

Microsoft Academic Search

This patent describes a resin composition having lubricating properties, which comprises; (i) 100 parts by weight of a synthetic resin, (ii) from 0.5 to 20.0 parts by weight of an organopolysiloxane, and (iii) from 0.5 to 20.0 parts by weight of a fluorine-containing elastomer or from 0.05 to 7.0 parts by weight of an alkoxysilane, wherein at least one of

M. Morozumi; M. Egami

1988-01-01

268

Method for permanently storing radioactive ion exchanger resins  

Microsoft Academic Search

A method is claimed for forming a hardened product containing a radioactive ion exchanger resin in a condition for permanent, noncontaminating storage, by the steps of: providing, before fixing, a mass of such ion exchanger resin saturated in water, the resin being at least one resin selected from the group consisting of spherical resins and powdered resins; mixing the resin

S. Kunze; G. Eden; R. Koster

1984-01-01

269

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

270

Maleimide Functionalized Siloxane Resins  

SciTech Connect

Polyorganosiloxanes are a commercially important class of compounds. They exhibit many important properties, including very low glass transition temperatures, making them useful over a wide temperature range. In practice, the polysiloxane polymer is often mixed with a filler material to help improve its mechanical properties. An alternative method for increasing polymer mechanical strength is through the incorporation of certain substituents on the polymer backbone. Hard substituents such as carbonates and imides generally result in improved mechanical properties of polysiloxanes. In this paper, we present the preparation of novel polysiloxane resins modified with hard maleimide substituents. Protected ethoxysilyl-substituted propyl-maleimides were prepared. The maleimide substituent was protected with a furanyl group and the monomer polymerized under aqueous acidic conditions. At elevated temperatures (>120 C), the polymer undergoes retro Diels-Alder reaction with release of foran (Equation 1). The deprotected polymer can then be selectively crosslinked by a forward Diels-Alder reaction (in the presence of a co-reactant having two or more dime functionalities).

Loy, D.A.; Shaltout, R.M.

1999-04-01

271

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

272

DEVELOPMENT OF WET-OXIDATION TREATMENT SYSTEM FOR FILTER BACKWASH SLUDGE AND ION EXCHANGE RESINS  

SciTech Connect

Decomposition of organic compounds contained in filter backwash sludge and spent ion exchange resins is considered effective in reducing the waste volume. A system using the wet-oxidation process has been studied for the treatment of the sludge and resins stored at Tsuruga Power Station Unit 1, 357MWe BWR, owned by The Japan Atomic Power Company. Compared with various processes for treating sludge and resin, the wet-oxidation system is rather simple and the process conditions are mild. Waste samples collected from storage tanks were processed by wet-oxidation and appropriate decomposition of the organic compounds was verified. After the decomposition the residue can be solidified with cement or bitumen for final disposal. When compared with direct solidification without decomposition, the number of waste packages can be reduced by a factor of a few dozens for the sludge and three for the resin. Additional measures for conditioning secondary waste products have also been studied, and their applicability to the Tsuruga Power Station was verified. Some of the conditions studied were specific to the Tsuruga Power Station, but it is expected that the system will provide an effective solution for sludge and resin treatment at other NPPs.

Miyamoto, T.; Motoyama, M.; Shibuya, M.; Wada, H.; Yamazaki, K.

2003-02-27

273

On the three-point flexural tests of dental polymeric resins.  

PubMed

Currently acrylic resins are commonly employed in many medical applications, especially for the fabrication of long span provisional restorations in dentistry and bone cement in orthopedics. On of the major problems associated with the conventional type of acrylic resins is their unsatisfactory mechanical properties. Among many attempts to strengthen acrylic resins, it has been demonstrated that they can be strengthened through the addition of reinforcement(s) as structural components of different size, shape and chemical composition, dispersed in the acrylic matrix, thus forming a composite structure. In the course of studies to strengthen dental polymeric resins by admixing various metallic oxide particles, PMMA-, PEMA-, and PIMA-based resins were reinforced by 2 vol.% added alumina, magnesia, zirconia, and silica powders. It was found that PMMA admixed with 2 vol.% zirconia exhibited the best improvement of mechanical properties (breaking strength, modulus of elasticity, offset yield strength, and fracture toughness as well). All tests were conducted under three-point bending. It was also found that the breaking strength based on the original sample dimension was, at most 20% less than those based on the final sample dimension. Moreover, this discrepancy was independent of the type of tested material, but dependent on the sample's modulus of elasticity. PMID:9262824

Oshida, Y; Zuccari, A G

1997-01-01

274

Different surface preparation techniques of porcelain repaired with composite resin and fracture resistance  

PubMed Central

Background: Porcelain from prosthesis such as crown or bridge can be fractured if exposed to trauma; and, can be repaired at chairside using composite resin. Aim: To investigate the fracture resistance of few techniques of surface preparation in repairing fractured porcelain using composite resin. Materials and Methods: Eighty samples of porcelain blocks were divided into 4 groups for different surface preparations, such as, Cimara repairing kit; porcelain etch kit containing hydrofluoric acid; Panavia F resin cement; and, sandblasting using aluminium oxide, before composite resin (Filtek Z250, 3M ESPE) was bonded to the prepared porcelain blocks. Twenty others samples in the control group comprised of pure porcelain blocks. The fracture resistance of each sample was tested using Instron machine (UK). Results: With the exception of the group repaired using hydrofluoric acid (3.04±1.04 Mpa), all the other groups showed significant difference in the fracture resistance values when compared to the control group (3.05 ± 1.42 MPa) at P<0.05. Conclusions: Etching of the porcelain blocks with hydrofluoric acid holds promise in the repair of fractured porcelain with composite resin at chairside.

Abd Wahab, Mohd Helmy Khalid; Bakar, Wan Zaripah Wan; Husein, Adam

2011-01-01

275

Dual ambroxal and chlorpheniramine resinate as an alternative carrier in concurrent resinate administration.  

PubMed

Two classical resinates, ambroxal (AMX) resinate and chlorpheniramine (CPM) resinate, and a novel formulation of dual AMX and CPM resinate were prepared by the batch method. The dissolution behavior of the drug from the classical resinates, a mixture of two classical resinates, and the dual-drug resinate in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) was examined and compared. The equilibrium of drug on to the resin and the re-exchange of the drug on to the resinate were also investigated. The drug release pattern from the resinate followed the particle diffusion process. The type of dissolution medium affected the amount of drug released from the resinate. The amount of drug released from the dual AMX and CPM resinate was not significantly different from that from the classical AMX resinate or CPM resinate (p < 0.05), but was considerably higher than that from the concurrent administration of two classical resinates (p > 0.05). These results indicated that the concurrent administration of the resinates affected drug release from the resinate, and the dual-drug resinate can be used as an alternative carrier for an ion-exchange delivery system. PMID:12685813

Akkaramongkolporn, P; Ngawhirunpat, T

2003-03-01

276

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

277

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

278

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

279

Marginal Integrity of CAD/CAM Fixed Partial Dentures  

PubMed Central

Objectives Computer-aided design (CAD) and manufacturing (CAM) allows the milling of high strength zirconia fixed partial dentures (FPD), however bonding to an inert ZrO2 ceramic surface may effect the marginal integrity of the FPDs. The aim of this investigation was to evaluate the marginal adaptation of zirconia FPDs at the interfaces between zirconia, cement, and tooth. Methods 32 3-unit FPDs were fabricated of the CAD/CAM Y-TZP zirconia (Lava, 3M Espe, Germany) according to the manufacturers’ instructions. Resin cements with corresponding primer and bonding systems were used to lute the FPDs: Compolute/EBS multi (3M Espe, Germany), Panavia F/ED (Kuraray, Japan), Variolink 2/Syntac classic (Ivoclar-Vivadent, FL) and RelyX Unicem/without treatment (3M Espe, Germany). Aualloy FPDs (BioPontostar, Bego, Germany) were cemented with RelyX Unicem and Harvard (Harvard, Germany) as the control. Marginal adaptation was evaluated with scanning electron microscopy using replica specimen before and after artificial aging. After aging, microleakage tests were performed with fuchsine solution. The interfaces between cement-tooth and cement-FPD were examined. Results At the interfaces (cement-tooth and cement-FPD), the systems showed a 95% or higher perfect margin before and after aging. Only Variolink2/Syntac had a marginal adaptation, lower than a 70% perfect margin. Generally, the fuchsine penetration was below 20%, only BioPontstar/Harvard andLava/Variolink2 showed penetration results between 80% and 100%. Conclusion The success of the adhesive cementation of zirconia FPDs depends on the cement system. Under the conditions of this study, zirconia FPDs showed good to sufficient marginal integrity in combination with Panavia/ED, Compolute/EBS and RelyX Unicem.

Rosentritt, Martin; Behr, Michael; Kolbeck, Carola; Handel, Gerhard

2007-01-01

280

Patch microstructure in cement-based materials: Fact or artefact?  

SciTech Connect

The appearance of patch microstructure, i.e. broad dense and porous regions separated by sharp and distinct boundaries and occurring randomly in bulk and interfacial transition zones, has been reported previously in various site- and laboratory-mixed concretes and mortars. In this paper, evidence is presented to show that patch microstructure is an artefact of sample preparation and does not reflect the true nature of the hydrated cement paste. The appearance of dense patches comes from paste areas that have been ground and polished beyond the epoxy resin intrusion depth. In a backscattered electron image, pores not filled with epoxy are not visible because the signal is generated from the base or side walls of the pores. A modified method for epoxy impregnation, which can achieve a much deeper epoxy penetration than conventional vacuum impregnation, is presented.

Wong, H.S. [Concrete Durability Group, Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ (United Kingdom)]. E-mail: hong.wong@imperial.ac.uk; Buenfeld, N.R. [Concrete Durability Group, Department of Civil and Environmental Engineering, Imperial College London, SW7 2AZ (United Kingdom)

2006-05-15

281

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

282

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

283

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

284

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

285

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

286

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

287

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

288

Molecular Self-Assembled Microcapsules Prepared by In Situ Polymerization Technology for Self-Healing Cement Materials  

Microsoft Academic Search

Monodisperse core–shell microcapsules have been widely used as self-healing cement materials and paid more attentions. A new\\u000a series of self-assembled microcapsules containing poly(styrene-divinylbenzene) as shell material were prepared by in situ\\u000a polymerization technology. The microencapsulating process of core material using mixture of epoxy resins and benzyl alcohol\\u000a was monitored using optical microscopy (OM). Morphology and shell wall thickness of microcapsule

Shenguang Ge; Fuwei Wan; Juanjuan Lu; Jinghua Yu

289

Alternative complete-arch cement-retained implant-supported fixed partial denture.  

PubMed

Early implant prostheses designs, which used screw-retained metal and acrylic resin structures, frequently left a space between the prosthesis and the soft tissue. Common deficiencies of this design included phonetic and esthetic problems and screw loosening. Cement-retained implant prostheses are also used in partially and completely edentulous patients, and are thought to have optimal occlusion and esthetics. Moreover, cement-retained prostheses may induce less stress on the implant, thereby maximizing the possibility of a passive fit. Porcelain fused to metal prostheses have been used mostly in partially edentulous situations. Recently, complete-arch porcelain fused to metal prostheses that replace hard and soft tissue have been used and, although this restoration can have excellent esthetics, there are disadvantages such as high cost, potential framework distortion during fabrication, and difficulty in repairing fractures of in-service porcelain. This article describes an alternative technique for the fabrication of a complete-arch, cement-retained, metal-acrylic resin implant-supported fixed partial denture. When compared with porcelain fused to metal complete-arch restorations, this prostheses is esthetic, has excellent retention and stability, yet is relatively inexpensive to fabricate, and requires less laboratory skill. PMID:10384169

Hofstede, T M; Ercoli, C; Hagan, M E

1999-07-01

290

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

291

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

292

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

293

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

294

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

295

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

296

21 CFR 175.270 - Poly(vinyl fluoride) resins.  

Code of Federal Regulations, 2010 CFR

...fluoride) resins consist of basic resins produced by the polymerization of...The poly(vinyl fluoride) basic resins have an intrinsic viscosity...technical grade. (2) Solution. Powdered resin and solvent are heated at...

2010-01-01

297

76 FR 4936 - Granular Polytetrafluoroethylene Resin From Italy  

Federal Register 2010, 2011, 2012, 2013

...Granular Polytetrafluoroethylene Resin From Italy AGENCY: United States International Trade...resin (``granular PTFE resin'') from Italy...duty orders on granular PTFE resin from Italy and Japan (75 FR 67082-67083 and...

2011-01-27

298

Epoxy Resins in Electron Microscopy  

PubMed Central

A method of embedding biological specimens in araldite 502 (Ciba) has been developed for materials available in the United States. Araldite-embedded tissues are suitable for electron microscopy, but the cutting qualities of the resin necessitates more than routine attention during microtomy. The rather high viscosity of araldite 502 also seems to be an unnecessary handicap. The less viscous epoxy epon 812 (Shell) produces specimens with improved cutting qualities, and has several features—low shrinkage and absence of specimen damage during cure, minimal compression of sections, relative absence of electron beam-induced section damage, etc.—which recommends it as a routine embedding material. The hardness of the cured resin can be easily adjusted by several methods to suit the materials embedded in it. Several problems and advantages of working with sections of epoxy resins are also discussed.

Finck, Henry

1960-01-01

299

The quasi-three-dimensional marginal leakage of full-coverage crowns: resin coating versus sodium hypochlorite treatment.  

PubMed

This study compared the effects of various surface treatments and techniques on the marginal leakage of full-coverage crowns using a quasi-three-dimensional evaluation. Crowns were cast using a gold-silver-palladium alloy by means of the lost-wax technique. Twenty-eight recently extracted human molars were divided randomly into four groups according to surface treatment before crown cementation: (1) no pretreatment (negative control), (2) primer (positive control), (3) resin coating and primer, and (4) phosphoric acid, sodium hypochlorite, and primer. All specimens were cemented with composite cement. The lowest marginal leakage was observed in group 4. Variation in marginal leakage between specimens originating from the same tooth was observed. PMID:20859554

Kawahara, Daizo; Mine, Atsushi; De Munck, Jan; Kuboki, Takuo; Yoshida, Yasuhiro; Suzuki, Kazuomi; Van Meerbeek, Bart; Yatani, Hirofumi

300

Phosphonic acid based ion exchange resins  

DOEpatents

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1996-01-01

301

Phosphonic acid based ion exchange resins  

DOEpatents

An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene disphosphonic acid with styrene, acrylonitrile and divinylbenzene.

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1994-01-01

302

21 CFR 177.1500 - Nylon resins.  

Code of Federal Regulations, 2010 CFR

...polymerization of Nylon 66 salts and epsilon -caprolactam. (5) Nylon 11 resins are manufactured...by the polymerization of epsilon- caprolactam. (7) Nylon 66T resins are manufactured...to 1 ratio by weight of epsilon -caprolactam and omega -laurolactam....

2009-04-01

303

21 CFR 177.1500 - Nylon resins.  

Code of Federal Regulations, 2010 CFR

...polymerization of Nylon 66 salts and epsilon -caprolactam. (5) Nylon 11 resins are manufactured...by the polymerization of epsilon- caprolactam. (7) Nylon 66T resins are manufactured...to 1 ratio by weight of epsilon -caprolactam and omega -laurolactam....

2010-01-01

304

21 CFR 177.1585 - Polyestercarbonate resins.  

Code of Federal Regulations, 2010 CFR

...Specifications. Polyestercarbonate resins identified in paragraph (a) of this section can be identified by their characteristic infrared spectrum. The resins shall comply with either or both of the following specifications: (i) The solution...

2009-04-01

305

21 CFR 177.1580 - Polycarbonate resins.  

Code of Federal Regulations, 2010 CFR

...c)(2) of this section. (1) Specification. Polycarbonate resins can be identified by their characteristic infrared spectrum. (2) Extractives limitations. The polycarbonate resins to be tested shall be ground or cut...

2009-04-01

306

21 CFR 177.1580 - Polycarbonate resins.  

Code of Federal Regulations, 2010 CFR

...c)(2) of this section. (1) Specification. Polycarbonate resins can be identified by their characteristic infrared spectrum. (2) Extractives limitations. The polycarbonate resins to be tested shall be ground or cut...

2010-01-01

307

21 CFR 177.1585 - Polyestercarbonate resins.  

Code of Federal Regulations, 2010 CFR

...Specifications. Polyestercarbonate resins identified in paragraph (a) of this section can be identified by their characteristic infrared spectrum. The resins shall comply with either or both of the following specifications: (i) The solution...

2010-01-01

308

21 CFR 177.1580 - Polycarbonate resins.  

Code of Federal Regulations, 2013 CFR

...paragraph (c)(2) of this section. (1) Specification. Polycarbonate resins can be identified by their characteristic infrared spectrum. (2) Extractives limitations. The polycarbonate resins to be tested shall be ground or cut into small...

2013-04-01

309

21 CFR 177.1585 - Polyestercarbonate resins.  

Code of Federal Regulations, 2013 CFR

...Specifications. Polyestercarbonate resins identified in paragraph (a) of this section can be identified by their characteristic infrared spectrum. The resins shall comply with either or both of the following specifications: (i) The solution intrinsic...

2013-04-01

310

21 CFR 872.3140 - Resin applicator.  

Code of Federal Regulations, 2013 CFR

... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3140 Resin applicator. (a) Identification. A resin applicator is a brushlike device...

2013-04-01

311

Method for loading resin beds  

DOEpatents

An improved method of preparing nuclear reactor fuel by carbonizing a uranium loaded cation exchange resin provided by contacting a H.sup.+ loaded resin with a uranyl nitrate solution deficient in nitrate, comprises providing the nitrate deficient solution by a method comprising the steps of reacting in a reaction zone maintained between about 145.degree.-200.degree. C, a first aqueous component comprising a uranyl nitrate solution having a boiling point of at least 145.degree. C with a second aqueous component to provide a gaseous phase containing HNO.sub.3 and a reaction product comprising an aqueous uranyl nitrate solution deficient in nitrate.

Notz, Karl J. (Oak Ridge, TN); Rainey, Robert H. (Knoxville, TN); Greene, Charles W. (Knoxville, TN); Shockley, William E. (Oak Ridge, TN)

1978-01-01

312

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

313

Condensate-polisher resin-leakage quantification and resin-transport studies. [PWR  

Microsoft Academic Search

The objectives of this program were to: (1) determine the extent of resin leakage from current generation condensate polisher systems, both deep bed and powdered resin design, during cut-in, steady-state and flow transient operation, (2) analyze moisture separator drains and other secondary system samples for resin fragments and (3) document the level of organics in the secondary system. Resin leakage

C. C. Stauffer; P. L. Doss

1983-01-01

314

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

315

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

316

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

317

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

318

Fluid Resin Technic of Processing Denture Bases.  

National Technical Information Service (NTIS)

The fluid resin technic of processing acrylic resin denture bases was recently adopted for use in the dental module of the Air Transportable Hospital. The new technic, described in detail in this review, utilizes a pourable auto-curing acrylic resin for t...

C. D. Miller G. L. Hall

1968-01-01

319

Hydrogen Peroxide as a Resin Cure Accelerator  

Microsoft Academic Search

The reaction of hydrogen peroxide with conventional resin adhesives was sufficiently exothermic for the heat to accelerate and improve resin cure in the hotpress. As a consequence, pressing times for medium density fibreboard, particleboard, and plywood could be reduced by up to 30% and, in some cases, better resin cure permitted a reduction in binder level. Differences in the interaction

K. M. Chapman; D. J. Jenkin

1986-01-01

320

Method for removing contaminants from plastic resin  

DOEpatents

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee' s Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2008-12-30

321

Method of removing contaminants from plastic resins  

DOEpatents

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee' s Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2008-11-18

322

Method of removing contaminants from plastic resins  

DOEpatents

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Bohnert,George W. (Harrisonville, MO); Hand,Thomas E. (Lee' s Summit, MO); Delaurentiis,Gary M. (Jamestown, CA)

2007-08-07

323

Method development for epoxy resin analysis  

Microsoft Academic Search

Epoxy resin based negative photo resists are showing interesting properties which are useful for a series of applications\\u000a in electronic industries (Mark et al. in Encyclopedia of polymer science and engineering, Wiley, New York, 1986; Potter in Epoxide resins, Springer, New York, 1970; May and Tanka in Epoxy resin chemistry and technology, Marcel Dekker, New York, 1973; Bauer in Epoxy

Sawa Nordt; Harald Pasch; Wolfgang Radke

2010-01-01

324

Characterization of the effects of post-extraction treatments on human dentin-resin interface by micro-Raman spectroscopy  

NASA Astrophysics Data System (ADS)

Raman microprobe spectroscopy was used to investigate the effects of post-extraction treatments of human dentin on the penetration of the 4-methacryloxyethyl trimellitic acid (4- MET)/methyl methacrylate (MMA)/tri-n-butyl borane (TBB) dentin adhesive. Human molar teeth, extracted and stored in distilled water or 70% ethanol solution for 7 or 28 days, were treated with the resin. Spatially resolved Raman microspectroscopy was used to measure penetration. The band intensity ratio 1612 cm-1 (resin): 962 cm-1 (dentin) was used as a diagnostic. Diffusion of the resin into dentin increased with the length of storage period. The results indicate that the effects of postextraction treatments on teeth must be considered when laboratory measurements of bonding strengths are employed to predict the clinical performance of dental cements. In addition, it is demonstrated that Raman microprobe spectroscopy is a feasible analytical tool to evaluate the effects of postextraction treatments on teeth.

Leung, Yiuchong; Morris, Michael D.

1997-01-01

325

Powdered epoxy resin test methods  

Microsoft Academic Search

The author describes several test methods which may be used to evaluate powdered epoxy resins for their potential use as integral insulation on fractional horsepower motor iron. These are the edge coverage test method, the hot plate gel time test method, the glass pellet flow test method, and the steel panel impact test method. These test methods may be of

N. Hanssen

1991-01-01

326

Imide Modified Epoxy Matrix Resins.  

National Technical Information Service (NTIS)

The results of a program designed to develop tough imide modified epoxy resins cured by bisimide amine (BIA) hardeners are described. State-of-the-art epoxides MY720 and DER383 were used, and four bismide amines were evaluated. These were the BIA's derive...

D. A. Scola

1984-01-01

327

Solventless Amine Epoxy Resin System.  

National Technical Information Service (NTIS)

A solventless amine-epoxy resin system is made up of (1) a binary aromatic amine mixture of 2,6-diaminopyridine and meta-phenylene diamine in a weight ratio of from about 1:4 to about 4:1; and (2) an epoxy mixture of (a) the diglycidyl ether of bisphenol ...

E. J. Rhyn K. R. Foote G. S. Handler J. P. Diebold

1977-01-01

328

Chelate Polymers of Phenolic Resin  

Microsoft Academic Search

Chelate polymers of the resin poly[3,5-(l-carboxy-2-hydroxy phenylene)ethyiene] with such bivalent ions as copper, nickel, cobalt, zinc, manganese, and trivalent iron have been synthesized. They have been analyzed, and some of their properties have been determined. On the basis of these, a polymeric structure is assigned to the polychelates.

M. N. Patel; J. B. Patel

1983-01-01

329

Photoelastic analysis of cemented or screwed implant-supported prostheses with different prosthetic connections.  

PubMed

The aim of this study was to evaluate the stress distribution of different retention systems (screwed or cemented) associated with different prosthetic connections (external hexagon, internal hexagon, and Morse taper) in 3-unit implant-supported fixed partial dentures through photoelasticity. Six models were fabricated with photoelastic resin PL-2, and each model contained two implants of 4.0 × 10.0 mm. The models presented different retention systems (screwed and cemented) and different connections (external hexagon, internal hexagon, and Morse taper). The prostheses were standardized and fabricated in Ni-Cr alloy. A circular polariscope was used and axial and oblique (45°) loads of 100 N were applied in a universal testing machine. The results were photographed and analyzed qualitatively with a graphic software (Adobe Photoshop). The screwed retention system exhibited higher number of fringes for both axial and oblique loadings. The internal hexagon implant presented better and lower stress distribution for both cemented and screwed prostheses. The oblique loading increased the number of fringes in all models tested. The cemented retention system presented better stress distribution. The internal hexagon implant was more favorable according to the biomechanical standpoint. The oblique load increased stress in all systems and connections tested. PMID:21851260

Tonella, Bianca Piccolotto; Pellizzer, Eduardo Piza; Ferraço, Renato; Falcón-Antenucci, Rosse Mary; Carvalho, Paulo S Perri de; Goiato, Marcelo Coelho

2011-08-01

330

Photoelastic analysis of cemented or screwed implant-supported prostheses with different prosthetic connections.  

PubMed

Abstract Purpose: the aim of this study was to evaluate the stress distribution of different retention systems (screwed or cemented) associated to different prosthetic connections (external hexagon, internal hexagon and morse taper) in 3-unit implant-supported fixed partial prostheses through photoelasticity. Materials and Method: Six models were fabricated with photoelastic resin PL-2 and each model contained two implants of 4.0X10.0mm. The models presented different retention systems (screwed and cemented) and different connections (external hexagon, internal hexagon and morse taper). The prostheses were standardized and fabricated in Ni-Cr alloy. A circular polariscope was used and axial and oblique (45 degrees) loads of 100N were applied in a universal testing machine. The results were photographed and analyzed qualitatively with a software (Adobe Photoshop). Results: The screwed retention system exhibited higher number of fringes for both axial and oblique loadings. The internal hexagon implant presented better and lower stress distribution for both cemented and screwed prostheses. The oblique loading increased the number of fringes in all models tested. Conclusions: The cemented retention system presented better stress distribution. The internal hexagon implant was more favorable according to the biomechanical standpoint. The oblique load increased stress in all systems and connections tested. PMID:20712445

Pellizzer, Eduardo; Tonella, Bianca; Ferraço, Renato; Falcón-Antenucci, Rosse Mary; de Carvalho, Paulo Sérgio; Goiato, Marcelo

2010-08-16

331

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

332

In vitro and in vivo studies on the toxicity of dental resin components: a review.  

PubMed

In vitro and in vivo studies have clearly identified that some components of restorative composite resins, adhesives, and resin-modified glass ionomer cements are toxic. The mechanisms of cytotoxicity are related firstly to the short-term release of free monomers occurring during the monomer-polymer conversion. Secondly, long-term release of leachable substances is generated by erosion and degradation over time. In addition, ion release and proliferation of bacteria located at the interface between the restorative material and dental tissues are also implicated in the tissue response. Molecular mechanisms involve glutathione depletion and reactive oxygen species (ROS) production as key factors leading to pulp or gingival cell apoptosis. Experimental animal approaches substantiate the occurrence of allergic reactions. There is a large gap between the results published by research laboratories and clinical reports. PMID:18040729

Goldberg, Michel

2007-11-27

333

Fractionation and utilization of gossypol resin  

SciTech Connect

Gossypol resin is formed as a secondary waste product during distillation of fatty acides isolated from cottonseed oil soap stocks; it is insoluble in water but soluble in products of petroleum distillation. For fractionation, gossypol resin was saponified with caustic soda or caustic potash. Using this method, the resin was separated into unsaponifiable (21-24%) and saponifiable (76-79%) parts. Details of the individual fractions of gossypol resin are presented. The unsaponifiable fraction contains hydrocarbons, alcohols, beta-sito-sterol, beta-amyrin, and vitamin E. The fatty acid fraction of the resin is a mixture of fatty acids and lactones.

Tursunov, A.K.; Dzhailov, A.T.; Fatkhullaev, E.; Sadykov, A.A.

1985-10-01

334

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

335

Two-year clinical evaluation of resinous restorative systems in non-carious cervical lesions.  

PubMed

This controlled clinical trial evaluated the 2-year clinical performance of a one-bottle etch-and-rinse adhesive and resin composite system (Excite/Tetric Ceram) compared to a resin-modified glass ionomer cement (RMGIC) (Vitremer/3M) in non-carious cervical lesions. Seventy cervical restorations (35 resin composite - RC- restorations and 35 RMGIC restorations) were placed by a single operator in 30 patients under rubber dam isolation without mechanical preparation. All restorations were evaluated blindly by 2 independent examiners using the modified USPHS criteria at baseline, and after 6, 12 and 24 months. Data were analyzed statistically by Fisher's exact and McNemar tests. After 2 years, 59 out of 70 restorations were evaluated. As much as 78.8% retention rate was recorded for RC restorations, while 100% retention was obtained for RMGIC restorations. Fisher's exact test showed significant differences (p=0.011) for retention. However, there were no significant differences for marginal integrity, marginal discoloration, anatomic form and secondary caries between the RC and RMGIC restorations. The McNemar test detected significant differences for Excite/TC between baseline and the 2-year recall for retention (p=0.02), marginal integrity (p=0.002) and anatomic form (p=0.04). Therefore, the one-bottle etch-and-rinse bonding system/resin composite showed an inferior clinical performance compared to the RMGIC. PMID:21203706

Santiago, Sérgio Lima; Passos, Vanara Florêncio; Vieira, Alessandra Helen Magacho; Navarro, Maria Fidela de Lima; Lauris, José Roberto Pereira; Franco, Eduardo Batista

2010-01-01

336

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

337

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

338

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

339

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

340

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

341

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

342

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

343

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

344

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

345

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

346

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

347

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

348

Pharmaceutical Applications of Ion-Exchange Resins  

NASA Astrophysics Data System (ADS)

The historical uses of ion-exchange resins and a summary of the basic chemical principles involved in the ion-exchange process are discussed. Specific applications of ion-exchange resins are provided. The utility of these agents to stabilize drugs are evaluated. Commonly occurring chemical and physical incompatibilities are reviewed. Ion-exchange resins have found applicability as inactive pharmaceutical constituents, particularly as disintegrants (inactive tablet ingredient whose function is to rapidly disrupt the tablet matrix on contact with gastric fluid). One of the more elegant approaches to improving palatability of ionizable drugs is the use of ion-exchange resins as taste-masking agents. The selection, optimization of drug:resin ratio and particle size, together with a review of scaleup of typical manufacturing processes for taste-masked products are provided. Ion-exchange resins have been extensively utilized in oral sustained-release products. The selection, optimization of drug:resin ratio and particle size, together with a summary of commonly occurring commercial sustained-release products are discussed. Ion-exchange resins have also been used in topical products for local application to the skin, including those where drug flux is controlled by a differential electrical current (ionotophoretic delivery). General applicability of ion-exchange resins, including ophthalmic delivery, nasal delivery, use as drugs in their own right (e.g., colestyramine, formerly referred to as cholestyramine), as well as measuring gastrointestinal transit times, are discussed. Finally, pharmaceutical monographs for ion-exchange resins are reviewed.

Elder, David P.

2005-04-01

349

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

350

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

351

ELUTION OF URANIUM FROM RESIN  

DOEpatents

A method is described for eluting uranium from anion exchange resins so as to decrease vanadium and iron contamination and permit recycle of the major portion of the eluats after recovery of the uranium. Diminution of vanadium and iron contamination of the major portion of the uranium is accomplished by treating the anion exchange resin, which is saturated with uranium complex by adsorption from a sulfuric acid leach liquor from an ore bearing uranium, vanadium and iron, with one column volume of eluant prepared by passing chlorine into ammonium hydroxide until the chloride content is about 1 N and the pH is about 1. The resin is then eluted with 8 to 9 column volumes of 0.9 N ammonium chloride--0.1 N hydrochloric acid solution. The eluants are collected separately and treated with ammonia to precipitate ammonium diuranate which is filtered therefrom. The uranium salt from the first eluant is contaminated with the major portion of ths vanadium and iron and is reworked, while the uranium recovered from the second eluant is relatively free of the undesirable vanadium and irons. The filtrate from the first eluant portion is discarded. The filtrate from the second eluant portion may be recycled after adding hydrochloric acid to increase the chloride ion concentration and adjust the pH to about 1.

McLEan, D.C.

1959-03-10

352

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

353

Scintillating 99Tc Selective Ion Exchange Resins  

SciTech Connect

Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

Mitchell Greenhalgh; Richard D. Tillotson

2012-07-01

354

Tactile learning in resin foraging honeybees  

Microsoft Academic Search

Honeybees harvest and use plant resins in a mixture called propolis to seal cracks and smooth surfaces in the nest architecture.\\u000a Resins in the nest may be important in maintaining a healthy colony due to their antimicrobial properties. This study had\\u000a two main objectives: (1) Provide initial insight on the learning capabilities of resin foraging honeybees; (2) analyze the\\u000a sensitivity

Michael Simone-Finstrom; Joel Gardner; Marla Spivak

2010-01-01

355

Pharmaceutical Applications of Ion-Exchange Resins  

Microsoft Academic Search

The historical uses of ion-exchange resins and a summary of the basic chemical principles involved in the ion-exchange process are discussed. Specific applications of ion-exchange resins are provided. The utility of these agents to stabilize drugs are evaluated. Commonly occurring chemical and physical incompatibilities are reviewed. Ion-exchange resins have found applicability as inactive pharmaceutical constituents, particularly as disintegrants (inactive tablet

David P. Elder

2005-01-01

356

Novel silica-based ion exchange resin  

SciTech Connect

Eichrom`s highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchange systems. Unlike conventional resins, Diphonix resin contains chelating ligands that are diphosphonic acid groups that recognize and remove the targeted metals and reject the more common elements such as sodium, calcium and magnesium. This latter property makes Diphonix ideal for many industrial scale applications, including those involving waste treatment. For treatment of low-level, transuranic (TRU) and high- level radioactive wastes, Diphonix`s polystyrene backbone hinders its application due to radiolytic stability of the carbon-hydrogen bonds and lack of compatibility with expected vitrification schemes. Polystyrene-based Diphonix is approximately 60% carbon- hydrogen. In response to an identified need within the Department of Energy for a resin with the positive attributes of Diphonix that also exhibits greater radiolytic stability and final waste form compatibility, Eichrom has successfully developed a new, silica-based resin version of Diphonix. Target application for this new resin is for use in environmental restoration and waste management situations involving the processing of low-level, transuranic and high-level radioactive wastes. The resin can also be used for processing liquid mixed waste (waste that contains low level radioactivity and hazardous constituents) including mixed wastes contaminated with organic compounds. Silica-based Diphonix is only 10% carbon-hydrogen, with the bulk of the matrix silica.

NONE

1997-11-01

357

Novolak resin analogs for resist applications  

NASA Astrophysics Data System (ADS)

Novolak resins, used to make typical g or i-line resists, are commonly made by condensing phenolic monomers with aldehydes. In the strictest definition of novolaks the aldehyde of choice is always formaldehyde. Under the acid catalyzed conditions generally used to make novolak the resins the carbocations formed by the protonation of the aldehydic carbonyl react with the phenolic reactant(s) to form the resins with elimination of water. Other aldehydes or low molecular weight ketones have been used on occasion to make useful analog for resist applications. Competing aldol condensations may interfere with isolation of pure polymeric resins especially in the case of ketones. Unique novolak resin analogs have been made by condensing `masked' bifunctional electrophiles with phenolic reactants under acidic conditions similar to standard novolak resin techniques. These resins were used as replacements for novolak resins and showed increased image contrast and thermal resistance. They were also used as photoactive compound backbones. Low molecular weight resins made with polyhydroxy aromatic phenolic monomers were especially useful as speed enhancing additives in thick film applications.

Wanat, Stanley F.; Jensen, Kathryn H.; Lu, Ping-Hung; McKenzie, Douglas S.

1998-06-01

358

Sand control with resin and explosive  

SciTech Connect

This patent describes a method for treating a well having perforated casing to prevent solids movement through the perforations and into the wellbore. It comprises positioning a quantity of liquid resin solution such that the solution occupies the interval of the casing having perforations; positioning an explosive in proximity with the liquid resin solution; detonating the explosive; displacing the liquid resin solution remaining in the wellbore after step (c) through the perforations with a displacing fluid; and injecting a chemical solution through the perforations to cause the resin to polymerize to form a consolidated permeable matrix.

Dees, J.M.; Begnaud, W.J.; Sahr, N.L.

1992-09-08

359

Microbiological Study of Water-Softener Resins  

PubMed Central

Microbial identification using effluents backflushed from exhausted urban and rural tank resins and cleaned resins containing the sulfonated copolymer of styrene and divinylbenzene (SDB) were completed, along with microbial assessment of the concentrated stock salt brine. Forty-four different bacterial and fungal genera were identified. Extensive biochemical and animal virulence tests completed on one of the six bacterial salt brine isolates indicated a pathogenic staphylococcal strain. The retention of Staphylococcus aureus, a Flavobacterium sp, and Escherichia coli B bacteriophage was demonstrated both by using the nonexhausted sodium-regenerated resin and by using the same resin exchanged with different mono-, di-, and trivalent cations. Effluent counts completed after bacterial seepage through the resins indicated the Pb++ exchanged resin removed 55% of the bacteria; Na+, Fe++, and Al+++ removed 31 to 36% and Ca++ and Cu++ removed about 10 to 15%. Seventy per cent or more of the bacteriophage was removed by Fe++, Cu++, and Al+++, whereas the Ca++ and Na++ cations removed 25 to 31%. Over a 77-day period, nonsterile tap water was passed through bacterial seeded and uninoculated SDB (Na) resin columns. Effluent and resin elution counts demonstrated the growth and survival of 2 different bacteria per column. Increased bacterial retention, survival, and multiplication occurred concomitantly with accumulation of organic and inorganic materials and the Ca++ and Mg++ cations from the tap water. Furthermore, microbial elution from resin particles taken from column depths of 1, 8, and 16 cm indicated a bacterial diminution with increasing depths.

Stamm, John M.; Engelhard, Warren E.; Parsons, James E.

1969-01-01

360

[Adaptability of composite resin inlays. 1. Adaptability to the experimental MOD cavity prepared in an acrylic block].  

PubMed

The adaptability of composite resin inlays was examined. CR Inlay and INLAY/ONLAY were used as materials. After the CR Inlay was polymerized in a U-form metal mold, the dimensional changes were measured before and after heating. Furthermore, the composite resin inlays made according to the manufacturer's instructions were cemented in an MOD type cavity and the film thickness of the cement was measured. The polymerization shrinkage of CR Inlay was 0.63% in the inside of the inlay and after heating it increased to 0.71%. The film thickness of the cement in the case of CR Inlay was more than 250 microns and that in the case of the INLAY/ONLAY was more than 750 microns in the MOD type cavity. Dentacolor XS (a box type photo generator) was better than Wite Lite (a handy type photo generator) for the polymerization of CR Inlay. Because of the poor adaptation of the inlays and the difficulty in removing a inlay from a stone model for CR Inlay, perhaps polymerization shrinkage of the inlay should be compensated in some way. PMID:2134823

Suzuki, T; Hosoki, S; Wakumoto, S

1990-07-01

361

Tires fuel oil field cement manufacturing  

SciTech Connect

In a new process, waste automobile tires added to the fuel mix of gas, coal, and coke help fire kilns to produce API-quality oil field cement. Capital Cement uses this process in its cement-manufacturing plant in San Antonio, in which it also produces construction cement. The tires provide a lower-cost fuel and boost the temperature at a critical stage in the kiln burn process. Also, steel-belted tires add iron content to the mix. According to lab results, tire-burned cement slurries will perform the same as conventionally burned cement slurries. Actual field applications have proven that cement produced by burning tires performs no different than conventionally produced slurries. Capital`s plant uses both dry and wet processes, with separate kilns running both processes at the same time. Cement clinker is partially fired by waste tires in both kiln processes. The tires represent 12% of the fuel consumed by the plant, a number that is expected to increase. Capital burns about 200 tires/hr, or about 1.6 million tires/year.

Caveny, B.; Ashford, D. [Halliburton Energy Services Inc., Duncan, OK (United States); Garcia, J.G. [Capital Cement, San Antonio, TX (United States); Hammack, R. [Halliburton Energy Services Inc., Alice, TX (United States)

1998-08-31

362

CELLULOSE CEMENT COMPOSITE MODIFIED BY POLYMER  

Microsoft Academic Search

The durability of the cellulose-cement composites is a deciding factor to introduce such material in the market. Several researches have been developed aiming to avoid the degradation of vegetable fiber-cement, some using chemically treated fibers and others modifying the matrix. Polymers have been used in concrete and mortar production to increase its durability. The goal of this work is to

L. L. Pimentel; A. L. Beraldo; H. Savastano Jr

363

TECHNOLOGICAL CHANGES IN THE CEMENT MANUFACTURING INDUSTRY.  

ERIC Educational Resources Information Center

|THE PURPOSE OF THIS STUDY IS TO PRESENT A PRELIMINARY PICTURE OF OCCUPATIONAL CHANGES BROUGHT ABOUT IN THE MANUFACTURE OF CEMENT AS A RESULT OF INTRODUCING AUTOMATED EQUIPMENT. ONE AUTOMATED AND SEVERAL CONVENTIONAL TYPE CEMENT PLANTS WERE STUDIED. ANALYSIS OF DATA OBTAINED THROUGH RESEARCH AND DATA COLLECTED DURING THE STUDY REVEALED THAT…

WESSON, CARL E.

364

Dental Silicate Cements: III. Environment and Durability  

Microsoft Academic Search

The nature of the aqueous environment has considerable effect on the durability of dental silicate cements. When free from soluble reaction products, cements show little dissolution in the pH range associated with normal saliva, but are drastically attacked by acids and citrates. These observations suggest that phosphates are important constituents of the gel matrix.

Alan D. Wilson; Reginald F. Batchelor

1968-01-01

365

Cement kiln temperature measurements using microwave radiometry  

Microsoft Academic Search

Conventional remote temperature measurements in cement kilns and other high-temperature industrial processes are often difficult or impossible because of the presence of dust that disables infrared remote temperature sensors. Microwave radiation is much less scattered by dust. Results from tests of an X-band microwave radiometer and antenna system at a cement kiln show that with calibration, this instrumentation will be

Karl D. Stephan; John A. Pearce; Lingyun Wang; Eric Ryza

2005-01-01

366

Polyacrylamide induced flocculation of a cement suspension  

Microsoft Academic Search

The use of cellulose, instead of asbestos, in the fibre cement composites manufacture, using the Hatschek process, reduces cement retention and makes necessary to use a flocculant which is crucial for the plant productivity. The use of different types and doses of polyacrylamides (PAM) as well as the addition process, have been studied to obtain an in-depth knowledge of floc

Carlos Negro; Luis M. Sánchez; Elena Fuente; Ángeles Blanco; Julio Tijero

2006-01-01

367

Cement Kiln Flue Gas Recovery Scrubber Project.  

National Technical Information Service (NTIS)

The Cement Kiln Flue Gas Recovery Scrubber Project was a technical success and demonstrated the following: CKD can be used successfully as the sole reagent for removing SO2 from cement kiln flue gas, with removal efficiencies of 90 percent or greater; Rem...

2001-01-01

368

Characterization of Cemented Sand in Triaxial Compression  

Microsoft Academic Search

This work aims at studying the stress-strain-strength behavior of an artificially cemented sandy soil produced through the addition of Portland cement. An analysis of the mechanical behavior of the soil is performed from the interpretation of results from unconfined compression tests, drained triaxial compression tests with local strain measurements, and scanning electron microscopy, in which the influence of both the

Fernando Schnaid; Pedro D. M. Prietto; Nilo C. Consoli

2001-01-01

369

Unique wellhead solves offshore cementing problems  

SciTech Connect

A special subsea wellhead assembly that allows 2stage cementing (from both top and bottom) in weak, unconsolidated seabed sediments has been used successfully from a semi-submersible rig offshore Malta. Presented here is a description of the system and a discussion of operational considerations used to set and cement 20 and 16-in. surface casing strings.

Not Available

1985-02-01

370

MODELING HYDRATION AND SETTING OF CEMENT  

Microsoft Academic Search

Hydration and setting of cement are complex processes involving chemical reactions and physical interactions which transform a collection of anhydrous grains into a massive hydrated solid. The understanding of all these processes and their synergy needs to develop simpler experimental models than cement which is polyphasic compound. Those experimental models have to be designed in such a way that: (i)

ANDRE NONAT

371

Cemented femoral fixation: the North Atlantic divide.  

PubMed

European nations, especially Scandinavian countries, have used cemented fixation since the introduction of total hip arthroplasty. In Sweden, with arguably the best national-level data on prostheses survivorship, >90% of all stems are fixated with cement. In sharp contrast, it is estimated that in the United States, >88% of all femoral stems use cementless technology. This represents a diametrically opposed difference in philosophical approach: the so-called North Atlantic Divide. The departure in North America from cemented femoral stems can be traced to the coinage of the phrase "cement disease," which implicated cement as a leading cause of osteolysis. This led to prolific innovation of uncemented technologies in North America, while European countries favored standardization enabled by the national arthroplasty registries. The term "cement disease" has been proven to be a misnomer, as supported by excellent outcomes from the Scandinavian registries, as well as excellent long-term outcomes for cemented stems in United States series, even in patients younger than 50 years. Like uncemented stems, there is variability in survivorship between femoral stems, and this appears to be related to specific design features. Despite the excellent long-term results, the use of cemented femoral components in Europe and Canada is decreasing in favor of uncemented stems. The reasons for this are not immediately obvious. PMID:19751019

Dunbar, Michael J

2009-09-01

372

Cementation in High-Latitude Dunes.  

National Technical Information Service (NTIS)

Cementing of dune sands by carbonates has not been considered to proceed rapidly in high-latitude regions. This study indicates that dunes along the Scotland coast, however, are actively being cemented by carbonates and that this process is quite widespre...

H. H. Roberts W. Ritchie A. Mather

1973-01-01

373

Basic studies on hydroxy apatite cement: I. Setting reaction.  

PubMed

Self-setting cements, alpha D-Cement and alpha DT-Cement, were prepared. They consisted of only the calcium phosphates alpha-TCP, TTCP and DCPA. These cements reacted and hardened in a moist environment at 37 degrees C. The powder X-ray diffraction patterns were taken to examine the conversion of their reactions as a function of time. The cements reacted and produced hydroxyapatite. The optimum powder/liquid ratio of alpha D-Cement was 2.0 and that of alpha DT-Cement was 1.8. The initial setting time of alpha D-Cement was 87.5 m and that of alpha DT-Cement was 107.5 m. The component and the product of these cements are calcium phosphates which are the putative minerals in teeth and bones. Therefore, these cements are useful for oral surgery as bone-filling materials. PMID:9680764

Fukase, Y; Wada, S; Uehara, H; Terakado, M; Sato, H; Nishiyama, M

1998-06-01

374

Tensile peel failure of resin-bonded Ni/Cr beams: an experimental and finite element study.  

PubMed

Tensile bond strength data for resin-bonded bridge cements would predict failure loads in excess of 1000 N when based on available bonded surface area. Such loads are unlikely to be encountered clinically, yet these bridges frequently fail. Loading conditions resulting in a peeling action at the adhesive interface may provide a more probable explanation for failure rather than being attributable to poor clinical or laboratory technique. This hypothesis was investigated by bonding grit-blasted Ni/Cr alloy beams of different thicknesses to a block of the same alloy using a resin-bonded bridge cement, leaving half the length of the beam free. Beams were pulled off the block with a peeling action by applying a tensile load to the free end of the beam and load at failure recorded. Fractured surfaces were examined under SEM. A two-dimensional finite element model of a section through the peel test arrangement was used to produce data of the stress distribution in the adhesive layer. Load at failure was closely correlated to beam thickness. Using this data and known tensile bond strength values it was possible to predict the loads necessary to cause adhesive failure of the beam, which were found to correlate closely with the experimental measurements. It was concluded that design and the stiffness of the retainers can have a potentially profound effect on the adhesive quality of resin-bonded bridges. PMID:7962902

Northeast, S E; van Noort, R; Shaglouf, A S

1994-08-01

375

Influence of cementation on liquefaction of sands  

SciTech Connect

Cementation can exist in a sand naturally or it can be added artificially. In either case, it is known to increase the resistance of a sand to liquefication, and can be a critical factor in engineering decisions about site response. This investigation involves testing of weakly cemented sands which have a range of cementation levels and unit weights. Both triaxial and cubical cyclic shear devices are used in the testing. The cubical shear apparatus is used to allow assessment of possible stress concentration effects in the triaxial device, and to investigate loading under multiaxial stress conditions. The experimental results are used to separate the effects of unit weight and cementation, and to define the conditions where cementation begins to override the influence of unit weight.

Clough, G.W.; Kuppusamy, T. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA). Dept. of Civil Engineering); Iwabuchi, J. (Central Res. Inst. for Constr. Tech., Tokyo (JP)); Rad, N.S. (Norwegian Geotech. Inst., Oslo (NO))

1989-08-01

376

Rigid centralizers improve cementing casing through caverns  

SciTech Connect

The use of off-center rigid centralizers on casing maintains a minimum annular space on the low side of a deviated well, improving cementing operations in such wells with hole enlargement problems. In deviated wells through carbonates or sloughing formations, caverns can form causing problems for hole cleaning and cementing operations. In hole-enlargement areas, the flow of both drilling fluid and cement is predominantly on the high side of the well, between the pipe and the top wall of the well. Drill cuttings can accumulate around the pipe near these caverns. During casing-running operations, the cement may not flow completely around the pipe in these cavernous sections. The study of cavern formation features in inclined wells can give a key to further prediction of technology for their washing and casing cementation. The paper describes a section gauge tool, field runs, and hole cleaning.

Kurochkin, B.M. [Scientific Research Inst. of Drilling Techniques, Moscow (Russian Federation)

1996-08-19

377

Improving wellhead performance with programmed cement shortfall  

SciTech Connect

Subsea wellheads can be subjected to extreme external loads when a drilling or production riser remains connected during storm or vessel drive-off conditions. In addition, vortex shedding from high currents and wave action on drilling and production risers can subject the wellhead to high-cycle fatigue loads. These extreme external and high-cycle fatigue loads can cause failure of the wellhead system when a fully cemented annulus between the 30-in. (76-cm) structural conductor pipe and 20-in. (51cm) surface casing is not achieved. This effect of cement shortfall is most damaging when the cement level is just below the wellhead-body/conductor-housing region. Purposefully setting the cement level far below the mudline can be a cost-effective solution to the unintentional cement-shortfall problem.

Britton, J.S.; Henderson, G.

1988-12-01

378

21 CFR 176.110 - Acrylamide-acrylic acid resins.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Acrylamide-acrylic acid resins. 176.110 Section 176.110 Food...Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be safely used as components...

2013-04-01

379

21 CFR 173.40 - Molecular sieve resins.  

Code of Federal Regulations, 2010 CFR

...40 Molecular sieve resins. Molecular sieve resins may be safely used...prescribed conditions: (a) The molecular sieve resins consist of purified dextran having an average molecular weight of 40,000,...

2010-01-01

380

21 CFR 173.40 - Molecular sieve resins.  

Code of Federal Regulations, 2010 CFR

...40 Molecular sieve resins. Molecular sieve resins may be safely used...prescribed conditions: (a) The molecular sieve resins consist of purified dextran having an average molecular weight of 40,000,...

2009-04-01

381

75 FR 67105 - Granular Polytetrafluoroethylene Resin From Italy and Japan  

Federal Register 2010, 2011, 2012, 2013

...Granular Polytetrafluoroethylene Resin From Italy and Japan AGENCY: United States International...granular polytetrafluoroethylene resin from Italy and Japan...granular polytetrafluoroethylene resin from Italy and Japan would be likely to lead to...

2010-11-01

382

40 CFR 721.3135 - Phosphorous modified epoxy resin (generic).  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Phosphorous modified epoxy resin (generic...Chemical Substances § 721.3135 Phosphorous modified epoxy resin (generic...substance identified generically as a phosphorous modified epoxy resin (PMNs...

2009-07-01

383

40 CFR 721.3135 - Phosphorous modified epoxy resin (generic).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Phosphorous modified epoxy resin (generic...Chemical Substances § 721.3135 Phosphorous modified epoxy resin (generic...substance identified generically as a phosphorous modified epoxy resin (PMNs...

2010-07-01

384

40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Epoxy resin containing phosphorus (generic). 721.2752 Section...721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance...generically as an epoxy resin containing phosphorus (PMN P-00-912) is subject...

2013-07-01

385

Hydrothermal cement/metal interfaces  

SciTech Connect

The authors investigated the adherence of two cementitious materials, calcium phosphate cement (CPC) and silica flour-filled class G cement (CGC), to metal substrates, such as cold-rolled steel (CRS), stainless steel (SS), electroplated zinc-coated steel (EZS), and zinc phosphate-coated steel (ZPS) after autoclaving at 200 C. In CPC/metal joints, the {gamma}-AlOOH phase, which segregated from the hydroxyapatite phase of the CPC matrix, was preferentially precipitated on the CRS and SS surfaces and also mixed with the reaction products formed at the interfaces between CPC and EZS or ZPS. Precipitation of {gamma}-AlOOH caused the formation of a weak boundary layer at the interfacial transition zones, thereby resulting in a low shear-bond strength. Although CGC accelerated the rate of corrosion of CRS and SS surfaces, the growth of Fe{sub 2}O{sub 3} clusters, formed as the corrosion products of metals at interfaces, aided the anchoring effect of xonotlite crystals as the major phase of CGC matrix, thereby conferring a high shear-bond strength. The EZS and ZPS surfaces were susceptible to alkali dissolution caused by the attack of the high-pH interstitial fluid of CGC pastes to the Zn and zinc phosphate coatings. Thus, the bond strengths of the CGC/EZS and /ZPS joints were lower than those of the joints made with CRS and SS.

Sugama, Toshifumi [Brookhaven National Lab., Upton, NY (United States); Baldwin, S. [Worcester Polytechnic Inst., MA (United States). Dept. of Chemistry

1996-01-01

386

Input to Resin Column Structural Analysis if Autocatalytic Resin Reaction Occurs in HB-Line Phase II  

Microsoft Academic Search

Solutions of plutonium in nitric acid are purified and concentrated using anion resin prior to precipitation. There have been instances of resin column explosions caused by autocatalytic reactions of anion resins in nitric acid within the DOE complex

Hallman

2001-01-01

387

In Vitro Mutagenicity Testing. I. Kermide 601 Resin, Sylgard 184 Encapsulating Resin, and Sylgard 184 Curing Agent.  

National Technical Information Service (NTIS)

Five compounds, Kerimide 601 resin, Sylgard 184 encapsulating resin, Sylgard 184 curing agent, benzo(a)pyrene, and acridine orange were tested for in vitro mutagenicity using the Ames Salmonella assay system. Kerimide 601 resin, Sylgard 184 encapsulating ...

S. Y. Wang D. M. Smith

1978-01-01

388

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2013 CFR

...dimethylamine and oxidized with hydrogen peroxide whereby the resin contains not...calcium, carbonate, chloride, hydrogen, hydroxyl, magnesium...cation-exchange resins in the hydrogen form identified in...

2013-04-01

389

Dentine sealing provided by smear layer/smear plugs vs. adhesive resins/resin tags.  

PubMed

The aim of this study was to evaluate the ability of five experimental resins, which ranged from hydrophobic to hydrophilic blends, to seal acid-etched dentine saturated with water or ethanol. The experimental resins (R1, R2, R3, R4, and R5) were evaluated as neat bonding agents (100% resin) or as solutions solvated with absolute ethanol (70% resin/30% ethanol). Fluid conductance was measured at 20 cm H(2)O hydrostatic pressure after sound dentine surfaces were: (i) covered with a smear layer; (ii) acid-etched; or (iii) bonded with neat or solvated resins, which were applied to acid-etched dentine saturated with water or ethanol. In general, the fluid conductance of resin-bonded dentine was significantly higher than that of smear layer-covered dentine. However, when the most hydrophobic neat resins (R1 and R2) were applied to acid-etched dentine saturated with ethanol, the fluid conductance was as low as that produced by smear layers. The fluid conductance of resin-bonded dentine saturated with ethanol was significantly lower than for resin bonded to water-saturated dentine, except for resin R4. Application of more hydrophobic resins may provide better sealing of acid-etched dentine if the substrate is saturated with ethanol instead of with water. PMID:17697173

Carrilho, Marcela R; Tay, Franklin R; Sword, Jeremy; Donnelly, Adam M; Agee, Kelli A; Nishitani, Yoshihiro; Sadek, Fernanda T; Carvalho, Ricardo M; Pashley, David H

2007-08-01

390

Influence of cement viscosity and cement mantle thickness on migration of the Exeter total hip prosthesis.  

PubMed

The effect of bone cement viscosity and cement mantle thickness on the migration of the Exeter total hip prosthesis was studied in a prospective, randomized, double-blind clinical Roentgen Stereophotogrammetric Analysis study. Forty-one cemented total hip arthroplasty in 39 patients were included and randomized into a low/medium Simplex P cement group and a high-viscosity Simplex AF cement group. At time of stem introduction, 5 minutes after mixing, the Simplex AF was more viscous than Simplex P. No statistical difference existed between the 2 cement groups, for neither translation nor rotation migration data. Subsidence of the stem at 2-year follow-up was 1.1 +/- 0.56 mm for Simplex AF cement and 1.5 +/- 1.00 mm for Simplex P cement. The mean rotation of the acetabular components about the sagittal axis was 1.7 degrees +/- 3.8 degrees in the Simplex AF group and 0.7 degrees +/- 2.1 degrees for the Simplex P group. No effect of cement mantle thickness on migration of neither the acetabular cups nor the femoral stems was found. Although there were no differences in migration data for the cups and the stems, 2 acetabular cups in the Simplex AF group (almost 10%) were revised because of mechanical loosening. Because of these findings, we suggest caution before using this new high-viscosity bone cement for fixation of acetabular components. PMID:16124971

Nelissen, Rob G H H; Garling, Eric H; Valstar, Edward R

2005-06-01

391

The marginal leakage of some dental cements in humans: a PIXE-microbeam approach  

NASA Astrophysics Data System (ADS)

The marginal leakage and water absorption of dental cements and restorative materials has been investigated by many authors with several techniques, some of which led to valid results. However, no technique could give, by itself, information both on leakage and water absorption, as these measurements usually need different investigations. PIXE micro beam offers the possibility of investigating these two aspects at the same time, since it is possible to map a proper marker element. In the present study, cavities were made on 50 extracted human molars, then filled with five different temporary cements (IRM, Cavit W, Kalsogen, Fermit N, SuperEBA). The filled teeth were placed into a 5% silver nitrate solution, and after three days, one, two, three and four weeks were examined. The samples for microPIXE were prepared after embedding the teeth in epoxy resin, and sectioning and grinding them down to a thickness of about 1 mm. The sections were placed on metal holders, and examined with a scanning proton ?beam, in Legnaro (Italy) at the AN2000 LAB of INFN National Laboratories. The beam consisted of 2.4 MeV protons, it had a cross section of 1.5 micron in diameter and typical currents of the order of some ?A were used. The maps were obtained by an ``ad hoc'' software with a McIntosh personal computer. Mapping of silver allowed to evaluate both the marginal leakage and the water absorption for each cement. The samples filled with Cavit W showed a great infiltration, as the tracing element was found in the cement bulk, along the margins and inside the cavity, while those filled with IRM and Kalsogen presented only a deposition of the tracing solution on the cement surface. SuperEBA showed a poor resistance against microleakage, because the marker element was only detected along the cavity margins. Fermit N showed the best marginal integrity, and on its surface no traces of siver were found. In this case the better resistance may be due to the resin present in the composition of the material.

Zadro, A.; Cavalleri, G.; Galassini, S.; Moschini, G.; Rossi, P.; Passi, P.

1999-06-01

392

Novel silica-based ion exchange resin  

SciTech Connect

Shortcomings of chelating resins have been addressed by a new class of ion exchange resins called dual mechanism bifunctional polymers (DMBPs). DMBPs use hydrophilic cation exchange ligands with rapid uptake kinetics and use chelating ligands for selectivity for one or more metals; result is a resin that quickly recognizes and removes targeted metals from waste, remediation, and process streams. Eichrom`s Diphonix {reg_sign} resin is the first DMBP to be widely released as a commercial product; it is polystyrene based. Objective of this work is to synthesize commercial quantities of a silica-based ion exchange resin with the same or better metal ion selectivity, metal uptake kinetics, and acid stability as Diphonix. Feasibility was determined, however the process needs to be optimized. Studies at Eichrom and ANL of the performance of Diphonix resin over a broad range of HNO3 and HCl conditions and inorganic salt loadings are discussed together with the proposed method of incorporating similar characteristics into a silica-based resin. The new, silica-based resin functionalized with diphosphonic acid ligands can be used in environmental restoration and waste management situations involving processing of low-level, transuranic, and high-level radioactive wastes; it can also be used for processing liquid mixed waste including wastes contaminated with organic compounds.

Gula, M.; Harvey, J.

1996-12-31

393

Ceramic Whisker Reinforcement of Dental Resin Composites  

Microsoft Academic Search

Resin composites currently available are not suitable for use as large stress-bearing posterior restorations involving cusps due to their tendencies toward excessive fracture and wear. The glass fillers in composites provide only limited reinforcement because of the brittleness and low strength of glass. The aim of the present study was to reinforce dental resins with ceramic single-crystalline whiskers of elongated

H. H. K. Xu; T. A. Martin; J. M. Antonucci; EC Eichmiller

1999-01-01

394

Novel process of isolating novolac resin fractions  

NASA Astrophysics Data System (ADS)

Typical phenol/formaldehyde resin syntheses generate a broad distribution of molecular weight fragments with a wide polydispersity. A process was developed to isolate novolak resin fractions of narrow polydispersity from phenol- formaldehyde condensation products in ethyl lactate without any high temperature distillation. The characterization and the performance of these fractions in i-line photoresist composition are discussed.

Rahman, M. Dalil; Lu, Ping-Hung; Cook, Michelle M.

1997-07-01

395

Prophylaxis with resin in wood ants  

Microsoft Academic Search

Animals may use plant compounds to defend themselves against parasites. Wood ants, Formica paralugub- ris, incorporate pieces of solidified conifer resin into their nests. This behaviour inhibits the growth of bac- teria and fungi in nest material and protects the ants against some detrimental microorganisms. Here, we studied the resin-collecting behaviour of ants under field and laboratory conditions. First, we

Gregoire Castella; Michel Chapuisat; Philippe Christe

2008-01-01

396

Epoxy resin composition having improved wetting properties  

US Patent & Trademark Office Database

An improved epoxy resin composition comprising an epoxy resin suitable for adhesive, potting or laminating use mixed with from about 0.1% to about less than 3% of an oxazolidine ester represented by the formula: ##EQU1## where R is an alkyl or alkenyl group of from 5 to 21 carbon atoms.

Sausaman; David K. (Terre Haute, IN)

1976-04-20

397

Fluoroaliphatic Cyanate Resins for Low Dielectric Applications.  

National Technical Information Service (NTIS)

The present invention is a cyanate resin monomer having the formula: NCO-CH2-(CF2)n-CH2-OCN where n is an even integer from 6 to 10, inclusive. Another aspect of the invention is an essentially pure cyanate resin monomer having the formula: NCO-CH2-(CF2)n...

A. W. Snow L. J. Buckley

1996-01-01

398

Hydraulic fracturing using reinforced resin pellets  

Microsoft Academic Search

A method of fracturing subterranean formations surrounding oil wells, gas wells, and similar boreholes is presented. The method employs a propping agent which permits the fractures to be propped in a partial monolayer pattern. It has been found that fractures with surprisingly high conductivities can be obtained by use of propping agents composed of reinforced synthetic resins. Synthetic resins without

1972-01-01

399

Fluorinated diamond bonded in fluorocarbon resin  

DOEpatents

By fluorinating diamond grit, the grit may be readily bonded into a fluorocarbon resin matrix. The matrix is formed by simple hot pressing techniques. Diamond grinding wheels may advantageously be manufactured using such a matrix. Teflon fluorocarbon resins are particularly well suited for using in forming the matrix.

Taylor, Gene W. (Los Alamos, NM)

1982-01-01

400

Photoelastic stress analysis in screwed and cemented implant-supported dentures with external hexagon implants.  

PubMed

The aim of this study was to assess the stress distribution of the retention systems (screwed and cemented) for implant-supported fixed partial dentures by means of photoelastic method. Two models were made of photoelastic resin PL-2 with 2 implants (phi = 4.00 x 10 mm) located in the second premolar and molar region in each photoelastic model, varying the retention system (screwed and cemented). The implant-supported fixed partial dentures were standardized and made of Ni-Cr alloy. Axial and oblique (45 degrees) forces of 100 N were applied on the occlusal surface by means of a Universal Testing Machine (EMIC-DL 3000; São José dos Pinhais, Paraná, Brazil). The results were observed and photographed in the field of a circular polariscope and qualitatively analyzed with the aid of computer software (Adobe Photoshop, San Jose, CA). The screw retention system presented the highest number of fringes when the loads were applied on the premolar, pontic, and molar and showed this behavior in all load applications, under axial and oblique loads. It was concluded that there was a better stress distribution and lower magnitude of stress on the cemented implant-supported dentures, under axial and oblique loads. Oblique load caused an increase in stress concentrations in all the models. PMID:20613577

Pellizzer, Eduardo Piza; Tonella, Bianca Piccolotto; Ferraço, Renato; Falcón-Antenucci, Rosse Mary; de Carvalho, Paulo Sérgio Perri; Alves-Rezende, Maria Cristina Rosifini

2010-07-01

401

Adsorption of pesticides on resins.  

PubMed

The objective of this work was to assess the capability of organic hydrophobic polymeric resins Amberlite XAD-4 and XAD-7 to remove the pesticides alachlor and amitrole from water. The pesticides adsorption on the two different adsorbents was measured by batch equilibrium technique and isotherm types and parameters were estimated. Two theoretical models were applied based on a Freundlich and a Langmuir isotherms. The effect of pesticides chemical composition and structure as well as the nature of solid surface on the efficiency of adsorption was evaluated. The influence of pH also was studied. In low pH solutions adsorption of amitrole was higher upon the nonionic aliphatic acrylic ester copolymer XAD-7 in comparison to the nonionic, crosslinked macroreticular copolymer of styrene divinylbenzene XAD-4. In neutral and intermediate pH solutions the polar acrylic ester copolymer XAD-7 was more effective to the retention of alachlor. The acrylic ester copolymer showed at pH 3 the lower effectiveness in alachlor removal from water. The data of the adsorption isotherms of pesticides upon the examined polymeric resins seemed to conform to both the Freundlich and the Langmuir isotherm models. PMID:12617554

Kyriakopoulos, Grigorios; Hourdakis, Adamadia; Doulia, Danae

2003-03-01

402

Formation of Hydroxyapatite in Cement Systems: Effects of Phosphate  

Microsoft Academic Search

The rate of hydroxyapatite (HA) formation in several calcium phosphate cement (CPC) systems was promoted when a phosphate solution instead of water was used as the cement liquid. The accelerated HA formation reduced the hardening time (HT) of the cements. In the cement system consisting of tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA), and distilled water, the presence of small

Laurence C. Chow; Milenko Markovic; Shozo Takagi

1999-01-01

403

XRD analysis and leachability of solidified phenol-cement mixtures  

Microsoft Academic Search

The microstructure and leachability of phenol from solidified phenol-Portland cement mixtures cured up to 6 months were investigated. Phenol was solidified with Type I Portland cement at concentrations of 0.5% and 2% by weight of the cement. XRD studies and pore fluid analyses indicate that phenol inhibits cement setting by reacting with the calcium hydroxide produced during the hydration of

C. Vipulanandan; S. Krishnan

1993-01-01

404

Vinylphosphonic acid-modified calcium aluminate and calcium silicate cements  

Microsoft Academic Search

Cementitious materials in terms of calcium phosphate cements (CPC) were prepared through the acid-base reaction between vinylphosphonic acid (VPA) and calcium aluminate cement (CAC) reactants or calcium silicate cement (CSC) reactants at 25 °C. Using CAC, two factors were responsible for the development of strength in the cements: one is the formation of an amorphous calcium-complexed vinylphosphonate (CCVP) salt phase

T. Sugama; R. N. Mora

1996-01-01

405

Continuous metal removal technique for resist resins  

NASA Astrophysics Data System (ADS)

Modern resists require very pure raw materials to insure highest quality images. Many methods have been developed to reduce metals in resins used to make photoresists. Extractive washing techniques and ion exchange methods have been the predominant methods used to reduce metal levels for these critical raw materials. This has been especially important for the novolak resins because of the generally poor quality of the starting materials used to make them and by the nature of the resin isolation steps traditionally used. Both of the commonly used cleaning methods are time consuming and are predominantly batch processes. Based upon techniques developed to efficiently fractionate resins, we have developed a technique for the rapid, continuous reduction of metal contaminants in film forming resin solutions by an extractive method using a double inlet liquid/liquid centrifuge.

Wanat, Stan F.; McKenzie, Douglas S.; Rahman, M. D.

2001-08-01

406

Correlating cement characteristics with rheology of paste  

SciTech Connect

The influence of cement characteristics such as cement fineness and clinker composition on the 'flow resistance' measured as the area under the shear stress-shear rate flow curve has been investigated. Three different types of plasticizers namely naphthalene sulphonate-formaldehyde condensate, polyether grafted polyacrylate, and lignosulphonate have been tested in this context on 6 different cements. The flow resistance correlated well with the cement characteristic (Blaine.{l_brace}d.cC{sub 3}A + [1 - d].C{sub 3}S{r_brace}) where the factor d represents relative reactivity of cubic C{sub 3}A and C{sub 3}S while cC{sub 3}A and C{sub 3}S represent the content of these minerals. It was found to be either a linear or exponential function of the combined cement characteristic depending on plasticizer type and dosage. The correlation was valid for a mix of pure cement and cement with fly ash, limestone filler (4%), as well as pastes with constant silica fume dosage, when the mineral contents were determined by Rietveld analysis of X-ray diffractograms.

Vikan, H. [SINTEF Building and Infrastructure, Concrete, 7465 Trondheim (Norway)], E-mail: hedda.vikan@sintef.no; Justnes, H. [SINTEF Building and Infrastructure, Concrete, 7465 Trondheim (Norway); Winnefeld, F.; Figi, R. [EMPA Swiss Federal Laboratories of Materials Testing and Research, 8600 Duebendorf (Switzerland)

2007-11-15

407

Current state of cement fixation in THR.  

PubMed

The author surveys important landmarks in the development of total hip arthroplasty, with an accent on implant fixation using acrylic cement. He explains why he personally opted for hybrid prostheses, combining a cemented stem and a cementless socket, in patients over sixty years. Excellent cementless, sockets have been available for a long time; on the femoral side, the first steps were difficult, but several cementless, stems were subsequently developed, which provided excellent long term results. This historical evolution resulted in a very uneven use of cemented versus cementless stems from one country to another in Europe. Cemented implants have enjoyed a renewed popularity over the past few years as a result of several factors, including economical factors. The author discusses the conditions for optimal fixation of a cemented stem; these conditions are not always met satisfactorily, as a number of surgeons obviously stick to a crude cementing technique. The author describes the role of the stem geometry and surface finish, as well as the possible influence of a centralizer; he explains why, based on a correct analysis of the available data, discredit has been unduly cast on cemented stems made of titanium alloy. He insists on one important although often disregarded factor: the specific type of cement used, as better results have clearly been achieved with certain cements than with others. He insists on the necessity to take into account all the elements involved, in order to avoid making erroneous conclusions. He also insists on one very important variable, the quality of the surgical technique. Total hip arthroplasty is likely to make further progress in the future, although we are likely now in the asymptotic portion of an ascending curve. Further improvement in clinical results will result from improvement of currently existing systems and optimization of surgical technique, rather than from the continuous designing of new implants. PMID:11915452

Morscher, E W; Wirz, D

2002-02-01

408

[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

409

Reinforcement of osteosynthesis screws with brushite cement.  

PubMed

The fixation of osteosynthesis screws remains a severe problem for fracture repair among osteoporotic patients. Polymethyl-methacrylate (PMMA) is routinely used to improve screw fixation, but this material has well-known drawbacks such as monomer toxicity, exothermic polymerization, and nonresorbability. Calcium phosphate cements have been developed for several years. Among these new bone substitution materials, brushite cements have the advantage of being injectable and resorbable. The aim of this study is to assess the reinforcement of osteosynthesis screws with brushite cement. Polyurethane foams, whose density is close to that of cancellous bone, were used as bone model. A hole was tapped in a foam sample, then brushite cement was injected. Trabecular osteosynthesis screws were inserted. After 24 h of aging in water, the stripping force was measured by a pull-out test. Screws (4.0 and 6.5 mm diameter) and two foam densities (0.14 and 0.28 g/cm3) were compared. Cements with varying solid/liquid ratios and xanthan contents were used in order to obtain the best screw reinforcement. During the pull-out test, the stripping force first increases to a maximum, then drops to a steady-state value until complete screw extraction. Both maximum force and plateau value increase drastically in the presence of cement. The highest stripping force is observed for 6.5-mm screws reinforced with cement in low-density foams. In this case, the stripping force is multiplied by 3.3 in the presence of cement. In a second experiment, cements with solid/liquid ratio ranging from 2.0 to 3.5 g/mL were used with 6.5-mm diameter screws. In some compositions, xanthan was added to improve injectability. The best results were obtained with 2.5 g/mL cement containing xanthan and with 3.0 g/mL cements without xanthan. A 0.9-kN maximal stripping force was observed with nonreinforced screws, while 1.9 kN was reached with reinforced screws. These first results are very promising regarding screw reinforcement with brushite cement. However, the polyurethane foam model presents noninterconnected porosity and physiological liquid was not modelized. PMID:10458285

Van Landuyt, P; Peter, B; Beluze, L; Lemaître, J

1999-08-01

410

Phosphate-bonded calcium aluminate cements  

DOEpatents

A method is described for making a rapid-setting phosphate-bonded cementitious material. A powdered aluminous cement is mixed with an aqueous solution of ammonium phosphate. The mixture is allowed to set to form an amorphous cementitious material which also may be hydrothermally treated at a temperature of from about 120.degree. C. to about 300.degree. C. to form a crystal-containing phosphate-bonded material. Also described are the cementitious products of this method and the cement composition which includes aluminous cement and ammonium polyphosphate.

Sugama, Toshifumi (Mastic Beach, NY)

1993-01-01

411

Setting Reaction of Polyacid Modified Composite Resins or Compomers  

PubMed Central

The hardening of modified polyacid composite resins (compomers) and glass-ionomers have been studied using infrared spectroscopy. The acid-base reaction in Ketac-fil, a glass ionomer, was followed by the ratio between the COOH band located around 1715 cm-1 and that corresponding to COO- located around 1570 cm-1. The combination of infrared analysis and band narrowing treatments enable us to propose in the glass-ionomer two maturation steps. First, a very rapid equilibrium acid-base related, and second the cross-linking of polycarboxylate with the metal ions present in the cement. In compomers, a new reaction has been described involving polymerization induced by free radicals besides the two steps associated with the acid-base reaction. Using infrared spectroscopy and band narrowing techniques, it is shown that water is essential to complete the hardening process but no acid-base reaction is produced since the COO- band does not appear. The reaction associated with free radicals could be described as a polymerization of methacrylate monomers together with an aqueous dilution of the filling particles releasing different metal cations that would chelate with the polymer molecules to form a macromolecular structure.

Arrondo, J.L.R; Collado, M.I; I, Soler; Triana, R; Ellacuria, J

2009-01-01

412

A blended cement containing blast furnace slag and phosphorous slag  

Microsoft Academic Search

Blended cement containing blast furnace slag (BFS) and phosphorous slag (PS) is a new kind of cement. The total content of\\u000a blended materials could increase if two additives were used. Using the same admixtures, the properties of the blended cement\\u000a with 70% additives could reach the standard of 525-grade slag cement according to GB. The strength of cement with 80%

Li Dong-xu; Chen Lin; Xu Zhong-zi; Luo Zhi-min

2002-01-01

413

Hydraulic cement-type fillers for hydrothermally stable polymer concretes  

Microsoft Academic Search

Hydraulic cement fillers, which can prevent the hydrothermal decomposition of vinyl-type polymer concrete (PC) containing carboxylate groups in the polymer molecule, have been developed. Experiments were performed in which a co-polymer was used in combination with an aggregate containing various commercial cements such as Portland type I, III, and V cements, slag cement (IS), and a Class H oil-well cement.

T. Sugama; L. E. Kukacka; W. Horn

1980-01-01

414

Fracture resistance of immature teeth filled with mineral trioxide aggregate or calcium-enriched mixture cement: An ex vivo study  

PubMed Central

Background: The ability of mineral trioxide aggregate (MTA) to strengthen the tooth structure has been studied with contradictory results, and there is a lack of data in the case of Calcium-enriched mixture (CEM) cement as a novel endodontic biomaterial. The aim of the present study was to evaluate the reinforcing effect of MTA and CEM cement on simulated immature teeth. Materials and Methods: This ex vivo study was carried out on a total of 46 human maxillary incisors. Access cavities were prepared. Five teeth were randomly selected as negative control. The root length of the remaining teeth was standardized to 9 mm. Rotary files and peeso reamers were used to enlarge the canals. The prepared specimens were randomly assigned into three experimental (n = 12) and a positive control (n = 5) groups. In groups 1 and 2, the canals were filled with MTA or CEM cement, respectively. In group 3, a 5-mm MTA plug was placed, and the remainder of the canal was filled with composite resin. The canals of the positive control were kept unfilled. After 6 months, the teeth were tested for fracture strength in a universal testing machine. The groups were compared using Univariate analysis of variance (ANOVA). Results: There were significant differences between fracture strength of experimental groups with that of both control groups (P<0.05). However, the differences among the three experimental groups were not statistically significant (P>0.05). Conclusion: After 6 months, MTA and CEM cement exhibit distinct reinforcing effect on immature teeth.

Milani, Amin Salem; Rahimi, Saeed; Borna, Zahra; Jafarabadi, Mohammad Asghari; Bahari, Mahmoud; Deljavan, Alireza Sighari

2012-01-01

415

Tc-99 Ion Exchange Resin Testing  

SciTech Connect

Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

2010-08-01

416

Effect of various surface treatments on the retention properties of titanium to implant restorative cement.  

PubMed

There are conflicting results in the literature and divergent manufacturers' recommendations concerning the retention properties of implant restorative cements, and they can provide inadequate retention of implants, especially short or single implants. The objective of this study was to investigate the effects of sandblasting and different types of laser irradiation on the interfacial bond between titanium and resin cement through shear testing. A total of 60 samples (10 mm in length and 12 mm in diameter) were cut from titanium rods. The samples were divided into four equal groups according to the surface treatment: control, sandblasted, Nd:YAG laser-irradiated, and Er:YAG laser-irradiated. After surface treatment, the implant restorative cements were applied to the titanium samples which were stored in distilled water at 37°C for 24 h. The samples were then subjected to shear bond strength testing using a universal testing machine with a crosshead speed of 1 mm/min. The data were analysed with the Kruskal-Wallis and Mann-Whitney U tests (??=?0.05). The highest mean bond strength was observed in the control group, followed by the sandblasted group. A statistically significant difference in shear bond strength was found between the sandblasted group and both the laser-irradiated groups (p?cement. PMID:22124579

Akin, Hakan; Guney, Umit

2011-11-29

417

Stability Analysis of a Cemented Rockfill Pillar.  

National Technical Information Service (NTIS)

The survival of many mines depends on their capability to maximize productivity while minimizing operating costs. The costs associated with cemented backfilling are best reduced by the optimization of mix design and thorough dimensioning. For environmenta...

H. Kuula

1996-01-01

418

Preparing Copper Powder from Cemented Copper.  

National Technical Information Service (NTIS)

Techniques were developed for preparing metallurgical-grade copper powder from industrially produced cement copper. Flotation was used for rejecting discrete gangue particles, acid leaching to remove residual iron and aluminum, hydrogen reduction to elimi...

J. K. Winter L. G. Evans R. D. Groves

1971-01-01

419

Studies on Soil-Cement Stabilization.  

National Technical Information Service (NTIS)

Soil-cement stabilization has been attempted on a large number of soil samples. An arbitrary criterion for minimum strength requirements has been assigned. Those soils that could not be stabilized and those requiring additional confirmatory tests have bee...

H. A. B. Rao

1968-01-01

420

Cementing Reactions in the Hazardous Waste Environment.  

National Technical Information Service (NTIS)

The use of chemical grout for bottom sealing waste sites requires careful consideration of interfering reactions from contaminated soil or ground water. The cementing reactions in the acrylates and urethanes are very specific. The presence of reducers, ox...

P. G. Malone

1984-01-01

421

Well cement fluid loss additive and method  

SciTech Connect

This patent describes a method of cementing a casing in a wellbore. It comprises pumping a cement slurry into the annulus between the casing and the wellbore, the cement slurry containing from 0.2 to 2.0 percent by weight, based on the weight of cement solids in the slurry, of an additive consisting essentially of from 30 to 80 percent by weight of partially hydrolyzed high molecular weight vinyl acetate polymer, calcium sulfate in an amount equivalent to from 10 to 60 percent by weight of calcium sulfate hemihydrate, up to 5 percent by weight of a cross-linking compound for the polyvinyl acetate, and from 0 to 5 percent by weight of defoamer.

Moran, L.K.; Murray, T.R.

1991-04-23

422

Corrosion of cemented titanium femoral stems.  

PubMed

Cemented titanium stems in hip arthroplasty are associated with proximal cement-stem ebonding and early failure. This was well publicised with the 3M Capital hip. However, corrosion in this setting has been reported with only one stem design and is less widely accepted. We present a series of 12 cemented titanium Furlong Straight Stems which required revision at a mean of 78 months for thigh pain. At revision the stems were severely corroded in a pattern which was typical of crevice corrosion. Symptoms were eliminated after revision to an all-stainless steel femoral prosthesis of the same design. We discuss the likely causes for the corrosion. The combination of a titanium stem and cement appears to facilitate crevice corrosion. PMID:15446521

Thomas, S R; Shukla, D; Latham, P D

2004-09-01

423

SEM and elemental analysis of composite resins  

SciTech Connect

Twenty-four chemically cured, 21 light-cured anterior, three light-cured anterior/posterior, and 18 light-cured posterior composite resins were examined using scanning electron microscopy, and the elemental composition of their filler particles was analyzed with an energy dispersive electron probe microanalyzer. According to the results obtained, the composite resins were divided into five groups (traditional, microfilled type, submicrofilled type, hybrid type, and semihybrid), with two additional hypothetical categories (microfilled and hybrid). Characteristics of each type were described with clinical indications for selective guidance of respective composite resins for clinical use.

Hosoda, H.; Yamada, T.; Inokoshi, S. (Tokyo Medical and Dental Univ., (Japan))

1990-12-01

424

Physicochemical characterisation of TMP resin and related model mixtures  

Microsoft Academic Search

A set of model resin mixtures were prepared to simulate Norway spruce thermomechanical pulp (TMP) resin at different conditions, such as in winter or summer, or after lipase and\\/or steryl esterase treatments. The resin samples were analysed on their viscosity, tackiness, wettability and surface energy; properties which may be related to the deposition tendency of wood resin. During production of

Menghua Qin; Tea Hannuksela; Bjarne Holmbom

2003-01-01

425

Reuse system for powdered ion-exchange resins  

Microsoft Academic Search

A reuse system has been developed for powdered ion-exchange resins generated from nuclear power plants in order to reduce their waste volume. The system consists of: 1. crud removal from resins; 2. decomposition of flocks (flocculated resins); 3. resin separation into cation and anion types; 4. regeneration of each type. The most important points in this system are items 2

K. Funabashi; T. Fukasawa; F. Kawamura; H. Yusa; M. Kikuchi; N. Sasaki; T. Yamadera

1986-01-01

426

Identification of selective ion-exchange resin for fluoride sorption  

Microsoft Academic Search

The defluoridation capacity (DC) of a chelating resin, namely Indion FR 10 (IND), and Ceralite IRA 400 (CER), an anion-exchange resin, were compared under various equilibrating conditions for the identification of selective sorbent. The results showed that chelating resin is more selective than an anion-exchange resin for fluoride removal. The fluoride sorption was reasonably explained using Freundlich and Langmuir isotherms.

S. Meenakshi; Natrayasamy Viswanathan

2007-01-01

427

ON THE CHEMICAL CONSTITUTION OF A LIGNITIC RESIN (thesis)  

Microsoft Academic Search

A sink-float procedure, employing a mixture of nheptane and CClâ ; as tbe separation medium, is a satisfactory means of separating the resins from ; the coal in a pure form. These resins are primarily resin acids and esters. The ; resin acids are composed of two major fractions, amber and a form of oxidized ; abietic acid. The oxidized

Tietjen

1958-01-01

428

New strong cement materials: chemically bonded ceramics  

Microsoft Academic Search

New cements developed in recent years have strengths that are greater by an order of magnitude than those of conventional hydraulic cements. These low-temperature materials, whose strengths approach those of many traditional high-temperature ceramics, are termed chemically bonded ceramics. The different routes to generating strong cementitious materials, including warm pressing, chemical modification, high-shear mixing with polymer additions, and the making

D. M. ROY

1987-01-01

429

Simulation of silica fume blended cement hydration  

Microsoft Academic Search

A model is proposed in this paper to simulate silica fume (SF) blended cement hydration based on the kinetics, stoichiometry\\u000a and physical chemistry of cement hydration and pozzolanic reaction. The pozzolanic reaction degree, volume fraction of hydration\\u000a products, capillary porosity and gel porosity can be obtained from model simulation. By using proper amount of silica fume\\u000a replacement, the microstructure of

J. Yajun; J. H. Cahyadi

2004-01-01

430

Reinforcement of osteosynthesis screws with brushite cement  

Microsoft Academic Search

The fixation of osteosynthesis screws remains a severe problem for fracture repair among osteoporotic patients. Poly-methyl-methacrylate (PMMA) is routinely used to improve screw fixation, but this material has well-known drawbacks such as monomer toxicity, exothermic polymerization, and nonresorbability. Calcium phosphate cements have been developed for several years. Among these new bone substitution materials, brushite cements have the advantage of being

P Van Landuyt; B Peter; L Beluze; J LemaÎtre

1999-01-01

431

Microwave radiometry for cement kiln temperature measurements.  

PubMed

The maximum temperature inside a cement kiln is a critical operating parameter, but is often difficult or impossible to measure. We present here the first data that show a correlation between cement kiln temperature measured using a microwave radiometer and product chemistry over an eight-hour period. The microwave radiometer senses radiation in the 12-13 GHz range and has been described previously [Stephan and Pearce (2002), JMPEE 37: 112-124]. PMID:17645204

Stephan, Karl D; Wang, Lingyun; Ryza, Eric

2007-01-01

432

Cellulose modified fibres in cement based composites  

Microsoft Academic Search

The objective of the present work is to evaluate the effect of surface modification of cellulose pulp fibres on the mechanical and microstructure of fibre–cement composites. Surface modification of the cellulose pulps was performed with Methacryloxypropyltri-methoxysilane (MPTS) and Aminopropyltri-ethoxysilane (APTS) in an attempt to improve their durability into fibre–cement composites. The surface modification showed significant influence on the microstructure of

G. H. D. Tonoli; U. P. Rodrigues Filho; H. Savastano Jr.; J. Bras; M. N. Belgacem; F. A. Rocco Lahr

2009-01-01

433

Condensate-polisher resin-leakage quantification and resin-transport studies. [PWR  

SciTech Connect

The objectives of this program were to: (1) determine the extent of resin leakage from current generation condensate polisher systems, both deep bed and powdered resin design, during cut-in, steady-state and flow transient operation, (2) analyze moisture separator drains and other secondary system samples for resin fragments and (3) document the level of organics in the secondary system. Resin leakage samples were obtained from nine-power stations that have either recirculating steam generators or once through steam generators. Secondary system samples were obtained from steam generator feedwater, recirculating steam generator blowdown and moisture separator drains. Analysis included ultraviolet light examination, SEM/EDX, resin quantification and infrared analysis. Data obtained from the various plants were compared and factors affecting resin leakage were summarized.

Stauffer, C.C.; Doss, P.L.

1983-04-01

434

Analysis of rheological properties of bone cements.  

PubMed

The rheological properties of three commercially available bone cements, CMW 1, Palacos R and Cemex ISOPLASTIC, were investigated. Testing was undertaken at both 25 and 37 degrees C using an oscillating parallel plate rheometer. Results showed that the three high viscosity cements exhibited distinct differences in curing rate, with CMW 1 curing in 8.7 min, Palacos R and Cemex ISOPLASTIC in 13 min at 25 degrees C. Furthermore it was found that these curing rates were strongly temperature dependent, with curing rates being halved at 37 degrees C. By monitoring the change of viscosity with time over the entire curing process, the results showed that these cements had differing viscosity profiles and hence exhibit very different handling characteristics. However, all the cements reached the same maximum viscosity of 75 x 10(3) Pa s. Also, the change in elastic/viscous moduli and tan delta with time, show the cements changing from a viscous material to an elastic solid with a clear peak in the viscous modulus during the latter stages of curing. These results give valuable information about the changes in rheological properties for each commercial bone cement, especially during the final curing process. PMID:17277981

Nicholas, M K D; Waters, M G J; Holford, K M; Adusei, G

2007-02-03

435

Case Study of the California Cement Industry  

SciTech Connect

California is the largest cement producing state in theU.S., accounting for between 10 percent and 15 percent of U.S. cementproduction and cement industry employment. The cement industry inCalifornia consists of 31 sites that consume large amounts of energy,annually: 1,600 GWh of electricity, 22 million therms of natural gas, 2.3million tons of coal, 0.25 tons of coke, and smaller amounts of wastematerials, including tires. The case study summarized in this paperfocused on providing background information, an assessment ofenergy-efficiency opportunities and barriers, and program recommendationsthat can be used by program planners to better target products to thecement industry. The primary approach to this case study involvedwalk-through surveys of customer facilities and in depth interviews withcustomer decision makers and subsequent analysis of collected data. Inaddition, a basic review of the cement production process was developed,and summary cement industry energy and economic data were collected, andanalyzed. The analysis of secondary data provides background informationon the cement industry and identification of potential energy-efficiencyopportunities. The interviews provide some understanding of the customerperspective about implementation of energy-efficiencyprojects.

Coito, Fred; Powell, Frank; Worrell, Ernst; Price, Lynn; Friedmann, Rafael

2005-05-01

436

Comparison of bond strength of three adhesives: composite resin, hybrid GIC, and glass-filled GIC.  

PubMed

The objective of this study was to compare 3 orthodontic adhesives in the areas of shear-peel bond strength, location of adhesive failure, and extent of enamel cracking before bonding and after debonding of orthodontic brackets. The adhesives included a composite resin control (Transbond XT; 3M/Unitek, St Paul, Minn), a resin-modified glass ionomer cement (Fuji Ortho LC; GC America Corp, Alsip, Ill), and a polyacid-modified composite resin under dry and saliva-contaminated conditions (Assure; Reliance Orthodontic Products Inc, Itasca, Ill). Metal brackets were bonded to the buccal surfaces of 160 (4 groups of 40) human premolars. The bonded teeth were stored in deionized water at 37 degrees C for 30 days and thermocycled for 24 hours before debonding with a Universal Instron (Instron Corp, Canton, Mass) testing machine. The extent of cracking in the buccal surfaces was evaluated under 16x magnification before bonding and after debonding. Although the bond strength of the composite resin control (20.19 MPa) was significantly greater (P <.05) than that of the adhesives in the other groups, clinically acceptable shear-peel bond strengths were found for all adhesives (Fuji Ortho LC = 13.57 MPa, Assure-dry = 10.74 MPa, Assure-wet = 10.99 MPa). The bond strength for the Assure adhesive was not significantly affected by saliva contamination. The sample of extracted premolars used in this study displayed a greater frequency of buccal surface enamel cracking (46.7%) than that reported in the literature for in vivo premolars (7.8%-10.2%), which was possibly due to the extraction process. The frequency of enamel cracking in a subset of this sample (n = 34) increased from 46.4% at prebonding to 62.4% at postdebonding as a result of the forces of debonding. PMID:11174538

Rix, D; Foley, T F; Mamandras, A

2001-01-01

437

Removal of Trace Contaminants from Water Using New Chelating Resins  

Microsoft Academic Search

The modification of cross?linked polyacrylamide (CPAAm) and incorporation of methyl thiourea (MeTU) or phenyl thiourea (PhTU) group were utilized in the preparation of two new chelating resins CPAAm?EDA?MeTU (resin I) and CPAAM?EDA?PhTU (resin II), [EDA=ethylenediamine]. The prepared resins were characterized by elemental analysis and IR spectroscopy. The sorption behaviors of Cd(II), Pb(II), and Zn(II) ions on the prepared resins were

Mohammed A. Sharaf; Said A. Sayed; Ahmed A. Younis; A. B. Farag; Hassan A. Arida

2007-01-01

438

Interlaminar Fracture Toughness in Resin Matrix Composites.  

National Technical Information Service (NTIS)

This annual report summarizes the objectives, accomplishments and proposed new directions of research on mode II interlaminar fracture in resin matrix composites. A mode II interlaminar fracture specimen, test and analysis method for interpreting results ...

L. W. Rehfield E. A. Armanios A. D. Reddy

1984-01-01

439

Analysis of Commercial Unsaturated Polyester Repair Resins.  

National Technical Information Service (NTIS)

The basic rheological, thermal, and mechanical properties of commercially available repair putties have been determined in this study, as has the composition of these products. These products contain 33% to 40% unsaturated polyester resin, 10% to 20% styr...

C. Greer I. McAninch J. M. Sands K. Andrews S. Bingham

2009-01-01

440

Passifloricins, polyketides ?-pyrones from Passiflora foetida resin  

Microsoft Academic Search

Three polyketides ?-pyrones, named passifloricins, were isolated from Passiflora foetida resin; their structures and relative configurations were assigned through 2D NMR spectroscopic analyses. These types of compounds were not detected in other passion flowers.

Fernando Echeverri; Victor Arango; Winston Quiñones; Fernando Torres; Gustavo Escobar; Yoni Rosero; Rosendo Archbold

2001-01-01

441

Method of Obtaining Phenol-Furfural Resins.  

National Technical Information Service (NTIS)

Invention relates to improvement of method of obtaining phenol-furfural resins, utilized in different branches of national economy as cationites (for purification of waste water from ions of calcium, magnesium, etc., sorption of different metals). Method ...

A. Y. Yuldashev D. R. Tursunova N. U. Rizayev Y. Z. Rakhman-Zade

1990-01-01

442

A Study of Soil Stabilization with Resins.  

National Technical Information Service (NTIS)

An investigation was conducted to determine the availability of new quick-curing resinous materials capable of stabilizing sand and silty clay soils by improving their strength characteristics. The investigation was aimed at overcoming the degrading effec...

H. A. Sultan J. D. Kriegh R. L. Sogge

1971-01-01

443

Mechanical Properties of Degraded PMR-15 Resin.  

National Technical Information Service (NTIS)

Thermo-oxidative aging produces a nonuniform degradation state in PMR-15 resin. A surface layer, usually attributed to oxidative degradation, forms. This surface layer has different properties from the inner material. A set of material tests was designed ...

L. C. Tsuji

2000-01-01