Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals.

Braz Dent J. 2007;18(1):20-3

Authors: Barbizam JV, Souza M, Cecchin D, Dabbel J

The purpose of this in vitro study was to evaluate the ability of a silicon-based root canal sealer, compared to zinc oxide and eugenol and an epoxy resin-based sealers, for filling of simulated lateral canals. Thirty extracted single-rooted human teeth were selected, conventional access was made and the working length was established 1 mm from the apical foramen. Three simulated lateral canals, one in each root third (coronal, middle and apical) were prepared in both the mesial and distal surfaces of each tooth using a size 15 reamer adapted to a low-speed handpiece. Each root canal was instrumented using ProTaper rotary files up to file F3 at the working length, and then irrigated with 2.5% NaOCl followed by EDTA. The teeth were assigned to 3 groups (n=10), according to the root canal sealer: Roeko Seal (Group 1), Sealer 26 (group 2) and Grossman's sealer (Group 3). Gutta-percha cold lateral condensation technique was performed in all groups. Postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5% significance level. The results showed that Grossman's sealer filled a larger number of lateral canals than Roeko Seal (p<0.05) and Sealer 26 (p<0.01). It may be concluded that Roeko Seal silicone-based root canal sealer was not as effective as the Grossman's sealer for filling of simulated lateral canals. The lateral canals localized in the apical third of the root were more difficult to be filled.

PMID: 17639195 [PubMed - indexed for MEDLINE]

Integrated nanogenerators in biofluid.

Nano Lett. 2007 Aug;7(8):2475-9

Authors: Wang X, Liu J, Song J, Wang ZL

We have demonstrated a prototype ZnO nanowire based nanogenerator (NG) that can effectively generate electricity inside biofluid when stimulated by ultrasonic waves. The potential of increasing output current and voltage was illustrated by connecting multiple NGs in parallel and serial, respectively, clearly demonstrating the possibility of raising output power by three-dimensional integration and architecture. The output current was increased by 20-30 times and reached as high as 35 nA when a 2 mm2 size NG was placed at a region where the ultrasonic waves were focused. This work unambiguously shows the feasibility of NGs for power conversion inside biofluid. It sets a solid foundation for self-powering implantable and wireless nanodevices and nanosystems in biofluid and any other type of liquid.

PMID: 17604406 [PubMed - indexed for MEDLINE]

Six closely related YbT2Zn20 (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy.

Proc Natl Acad Sci U S A. 2007 Jun 12;104(24):9960-3

Authors: Torikachvili MS, Jia S, Mun ED, Hannahs ST, Black RC, Neils WK, Martien D, Bud'ko SL, Canfield PC

Heavy fermion compounds represent one of the most strongly correlated forms of electronic matter and give rise to low temperature states that range from small moment ordering to exotic superconductivity, both of which are often in close proximity to quantum critical points. These strong electronic correlations are associated with the transfer of entropy from the local moment degrees of freedom to the conduction electrons, and, as such, are intimately related to the low temperature degeneracy of the (originally) moment bearing ion. Here we report the discovery of six closely related Yb-based heavy fermion compounds, YbT(2)Zn(20), that are members of the larger family of dilute rare earth bearing compounds: RT(2)Zn(20) (T = Fe, Co, Ru, Rh, Os, Ir). This discovery doubles the total number of Yb-based heavy fermion materials. Given these compounds' dilute nature, systematic changes in T only weakly perturb the Yb site and allow for insight into the effects of degeneracy on the thermodynamic and transport properties of these model correlated electron systems.

PMID: 17551012 [PubMed - indexed for MEDLINE]

Physical sunscreens: on the comeback trail.

Indian J Dermatol Venereol Leprol. 2007 Mar-Apr;73(2):80-5

Authors: More BD

Awareness of ultraviolet radiation-induced skin damage creates the need for the development of broad-spectrum, safe and cosmetically acceptable sunscreens. Being relatively inert, safe, stable and non-irritating, physical sunscreens are particularly useful for patients with sensitive skin who cannot tolerate chemical sunscreens. However, they form a thick visible pigment layer on the skin. To overcome this drawback, microfine oxides have been developed which made the sunscreens virtually transparent when applied on the skin. This article reviews the rationale for the comeback of physical sunscreens by analyzing data from various sources.

PMID: 17456911 [PubMed - indexed for MEDLINE]

Induction of inflammation in vascular endothelial cells by metal oxide nanoparticles: effect of particle composition.

Environ Health Perspect. 2007 Mar;115(3):403-9

Authors: Gojova A, Guo B, Kota RS, Rutledge JC, Kennedy IM, Barakat AI

BACKGROUND: The mechanisms governing the correlation between exposure to ultrafine particles and the increased incidence of cardiovascular disease remain unknown. Ultrafine particles appear to cross the pulmonary epithelial barrier into the bloodstream, raising the possibility of direct contact with the vascular endothelium. OBJECTIVES: Because endothelial inflammation is critical for the development of cardiovascular pathology, we hypothesized that direct exposure of human aortic endothelial cells (HAECs) to ultrafine particles induces an inflammatory response and that this response depends on particle composition. METHODS: To test the hypothesis, we incubated HAECs for 1-8 hr with different concentrations (0.001-50 mug/mL) of iron oxide (Fe(2)O(3)), yttrium oxide (Y(2)O(3)), and zinc oxide (ZnO) nanoparticles and subsequently measured mRNA and protein levels of the three inflammatory markers intra-cellular cell adhesion molecule-1, interleukin-8, and monocyte chemotactic protein-1. We also determined nanoparticle interactions with HAECs using inductively coupled plasma mass spectrometry and transmission electron microscopy. RESULTS: Our data indicate that nanoparticle delivery to the HAEC surface and uptake within the cells correlate directly with particle concentration in the cell culture medium. All three types of nanoparticles are internalized into HAECs and are often found within intracellular vesicles. Fe(2)O(3) nanoparticles fail to provoke an inflammatory response in HAECs at any of the concentrations tested; however, Y(2)O(3) and ZnO nanoparticles elicit a pronounced inflammatory response above a threshold concentration of 10 mug/mL. At the highest concentration, ZnO nanoparticles are cytotoxic and lead to considerable cell death. CONCLUSIONS: These results demonstrate that inflammation in HAECs following acute exposure to metal oxide nanoparticles depends on particle composition.

PMID: 17431490 [PubMed - indexed for MEDLINE]

Apical surgery with calcium hydroxide capping of the exposed dentine: a case report.

J Oral Sci. 2007 Mar;49(1):79-83

Authors: Soares JA, Silveira FF, Nunes E

Among a variety of biomaterials that have been reported to be ideal for dental repair, calcium hydroxide has been shown to have excellent long-term biocompatibility in the pulp and periapical areas. Here we report an alternative method employing calcium hydroxide for periapical surgery in a patient who developed internal apical resorption after traumatic injury, which negatively affected the quality of the cleaning, shaping and filling of the root canal. Obturation of the root canal as far as the middle third was followed by apicoectomy and ultrasonic retropreparation, and then retrograde root filling with resin cement sealer (Sealer 26) and zinc oxide powder. Calcium hydroxide paste was applied over the exposed dentinal surface, forming a barrier over the root apex. Radiographic follow-up after 24 months showed absence of apical resorption and complete periapical bone repair associated with a continuous apical lamina dura. (J. Oral Sci. 49, 79-83, 2007).

PMID: 17429187 [PubMed - in process]

In vitro antimicrobial activity of endodontic sealers, MTA-based cements and Portland cement.

J Oral Sci. 2007 Mar;49(1):41-5

Authors: Tanomaru-Filho M, Tanomaru JM, Barros DB, Watanabe E, Ito IY

The aim of this study was to evaluate the antimicrobial activity of different root-end filling materials - Sealer 26, Sealapex with zinc oxide, zinc oxide and eugenol, white and gray Portland cement, white and gray MTA-Angelus, and gray Pro Root MTA - against six different microorganism strains. The agar diffusion method was used. A base layer was made using M&#xFC;ller-Hinton agar (MH) and wells were formed by removing the agar. The materials were placed in the wells immediately after manipulation. The microorganisms used were: Micrococcus luteus (ATCC9341), Staphylococcus aureus (ATCC6538), Escherichia coli (ATCC10538), Pseudomonas aeruginosa (ATCC27853), Candida albicans (ATCC 10231), and Enterococcus faecalis (ATCC 10541). The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37 degrees C for 24 h. Triphenyltetrazolium chloride 0.05% gel was added for optimization, and the zones of inhibition were measured. Data were subjected to the Kruskal-Wallis and Dunn tests at a 5% significance level. The results showed that all materials had antimicrobial activity against all the tested strains. Analysis of the efficacy of the materials against the microbial strains showed that Sealapex with zinc oxide, zinc oxide and eugenol and Sealer 26 created larger inhibition halos than the MTA-based and Portland cements (P < 0.05). On the basis of the methodology used, it may be concluded that all endodontic sealers, MTA-based and Portland cements evaluated in this study possess antimicrobial activity, particularly the endodontic sealers. (J. Oral Sci. 49, 41-45, 2007).

PMID: 17429181 [PubMed - in process]

Antimicrobial analysis of different root canal filling pastes used in pediatric dentistry by two experimental methods.

Braz Dent J. 2006;17(4):317-22

Authors: Amorim Lde F, Toledo OA, Estrela CR, Decurcio Dde A, Estrela C

The objective of this study was to compare, by two experimental methods, the antimicrobial efficacy of different root canal filling pastes used in pediatric dentistry. The tested materials were: Guedes-Pinto paste (GPP), zinc oxide-eugenol paste (OZEP), calcium hydroxide paste (CHP), chloramphenicol + tetracycline + zinc oxide and eugenol paste (CTZP) and Vitapex. Fiven microbial strains (S. aureus, E. faecalis, P. aeruginosa, B. subtilis and C. albicans) obtained from the American Type Culture Collection were inoculated in Brain Heart Infusion (BHI) and incubated at 37 degrees C for 24 h. For the direct exposure test (DET), 72 paper points were contaminated with the standard microbial suspensions and exposed to the root canal filling pastes for 1, 24, 48 and 72 h. The points were immersed in Letheen Broth (LB), followed by incubation at 37 degrees C for 48 h. An inoculum of 0.1 mL obtained from LB was then transferred to 7 mL of BHI, under identical incubations conditions and the microbial growth was evaluated. The pastes showed activity between 1 and 24 h, depending on the material. For the agar diffusion test (ADT), 30 Petri plates with 20 mL of BHI agar were inoculated with 0.1 mL of the microbial suspension, using sterile swabs that were spread on the medium. Three cavities were made in each agar plate (total = 90) and completely filled with one of the filling root canal pastes. The plates were pre-incubated for 1 h at room temperature and then incubated at 37 degrees C for 24 to 48 h. The inhibition zone around each well was recorded in mm. The complete antimicrobial effect in the direct exposure test was observed after 24 h on all microbial indicators. All root canal filling materials induced the formation of inhibition zones, except for Vitapex (range, 6.0-39.0 mm).

PMID: 17262146 [PubMed - indexed for MEDLINE]

Piezoelectric field effect transistor and nanoforce sensor based on a single ZnO nanowire.

Nano Lett. 2006 Dec;6(12):2768-72

Authors: Wang X, Zhou J, Song J, Liu J, Xu N, Wang ZL

Utilizing the coupled piezoelectric and semiconducting dual properties of ZnO, we demonstrate a piezoelectric field effect transistor (PE-FET) that is composed of a ZnO nanowire (NW) (or nanobelt) bridging across two Ohmic contacts, in which the source to drain current is controlled by the bending of the NW. A possible mechanism for the PE-FET is suggested to be associated with the carrier trapping effect and the creation of a charge depletion zone under elastic deformatioin. This PE-FET has been applied as a force/pressure sensor for measuring forces in the nanonewton range and even smaller with the use of smaller NWs. An almost linear relationship between the bending force and the conductance was found at small bending regions, demonstrating the principle of nanowire-based nanoforce and nanopressure sensors.

PMID: 17163703 [PubMed - indexed for MEDLINE]

Does the use of calamine or antihistamine provide symptomatic relief from pruritus in children with varicella zoster infection?

Arch Dis Child. 2006 Dec;91(12):1035-6

Authors: Tebruegge M, Kuruvilla M, Margarson I

PMID: 17119083 [PubMed - indexed for MEDLINE]

Influence of dietary zinc and copper on digestive enzyme activity and intestinal morphology in weaned pigs.

J Anim Sci. 2006 Dec;84(12):3310-20

Authors: Hedemann MS, Jensen BB, Poulsen HD

The current study was conducted to investigate the effects of high dietary concentrations of Zn as zinc oxide and Cu as copper sulfate on the activity of digestive enzymes in the pancreas and the intestinal mucosa, intestinal morphology, and mucin histochemistry in pigs after weaning. Thirty-two pigs were weaned at 4 wk of age. The pigs were fed standard weaning diets supplemented with Zn (100 or 2,500 ppm) and Cu (0 or 175 ppm) in a 2 x 2 factorial arrangement of treatments for a 14-d period. In pancreatic tissue, the activity of amylase, carboxypeptidase A, chymotrypsin, trypsin, and lipase increased (P < 0.01) in pigs fed 2,500 ppm of Zn, whereas the activity of carboxypeptidase B and carboxylester hydrolase was unaffected. Copper had no effect on the activity of pancreatic enzymes. In small intestinal contents, the total activity of amylase and carboxypeptidase A was greater in pigs fed 100 ppm of Zn (P < 0.05), whereas feeding 2,500 ppm of Zn increased the chymotrypsin activity (P < 0.001). The remaining enzymes were unaffected by dietary Zn concentration. The villi were longer in the cranial small intestine (P < 0.001) in pigs fed 100 ppm of Zn than in pigs fed 2,500 ppm of Zn, but otherwise there were no clear effects of Zn and Cu supplementation on intestinal morphology. In the cranial small intestine, the activity of maltase (P < 0.001), sucrase (P < 0.001), and lactase was greater in pigs fed 100 ppm of Zn, even though there was a Zn x Cu interaction (P < 0.05) in lactase activity. In the middle and caudal small intestine, no clear differences between dietary treatments were observed. The activity of gamma-glutamyl transpeptidase in the intestinal mucosa was not affected by dietary Zn or Cu. In pigs fed 100 ppm of Zn, the activity of aminopeptidase N was greater in the caudal small intestine, but dietary Zn or Cu had no effect on aminopeptidase N in the cranial and middle small intestine. No effect of dietary Zn or Cu supplementation was found on carbohydrate histochemistry in the caudal small intestine, whereas high dietary Zn increased the area of neutral, acidic, and sulfomucins in the cecum (P < 0.01) and in the colon (P < 0.001). In summary, high dietary Zn increased the activity of several enzymes in the pancreatic tissue and increased the mucin staining area in the large intestine, whereas Cu had no clear effect on these variables. However, no definite answers were found as to how the growth promoting and diarrhea reducing effects of excess dietary Zn are exerted.

PMID: 17093223 [PubMed - indexed for MEDLINE]

Fortifying milk with ferrous gluconate and zinc oxide in a public nutrition program reduced the prevalence of anemia in toddlers.

J Nutr. 2006 Oct;136(10):2633-7

Authors: Villalpando S, Shamah T, Rivera JA, Lara Y, Monterrubio E

We aimed to assess the efficacy of whole cow's milk fortified with ferrous gluconate and zinc oxide, along with ascorbic acid, in reducing the prevalence of anemia and improving iron status of low income children 10-30 mo of age. Healthy children were randomly assigned to drink 400 mL/d of cow's whole milk, either fortified milk (FM) with 5.8 mg/400 mL of iron as ferrous gluconate, 5.28 mg/400 mL of zinc as zinc oxide, and 48 mg/400 mL of ascorbic acid, or nonfortified milk (NFM) with 0.2 mg iron/400 mL, 1.9 mg zinc/400 mL, and 6.8 mg ascorbic acid/400 mL. Hemoglobin, serum ferritin, soluble transferrin receptors (TfR), and C-reactive protein concentrations were measured at baseline and 6 mo after intervention. The prevalence of anemia declined from 41.4 to 12.1% (P < 0.001), or 29 percentage points, in the FM group; there was no change in the NFM group. Hemoglobin (coefficient = 0.22, P < 0.01) was positively and TfR (coefficient = -0.29, P < 0.001) negatively associated with treatment, controlling for their respective baseline values, age, and gender. Treatment with FM was negatively associated with the likelihood of being anemic (pseudo R(2) = 0.085, P < 0.03) after 6 mo of intervention. Ferrous gluconate added to whole cow's milk as a fortificant along with ascorbic acid is efficacious in reducing the prevalence of anemia and in improving iron status of Mexican toddlers. The results of this study lead to broadening a subsidized FM distribution program to 4.2 million beneficiary children 1-11 y of age in Mexico.

PMID: 16988138 [PubMed - indexed for MEDLINE]

Solution-grown zinc oxide nanowires.

Inorg Chem. 2006 Sep 18;45(19):7535-43

Authors: Greene LE, Yuhas BD, Law M, Zitoun D, Yang P

We review two strategies for growing ZnO nanowires from zinc salts in aqueous and organic solvents. Wire arrays with diameters in the nanoscale regime can be grown in an aqueous solution of zinc nitrate and hexamethylenetetramine. With the addition of poly(ethylenimine), the lengths of the wires have been increased to 25 mum with aspect ratios over 125. Additionally, these arrays were made vertical by nucleating the wires from oriented ZnO nanocrystals. ZnO nanowire bundles have been produced by decomposing zinc acetate in trioctylamine. By the addition of a metal salt to the solution, the ZnO wires can be doped with a range of transition metals. Specifically, ZnO nanowires were homogeneously doped with cobalt and showed a marked deviation from paramagnetic behavior. We conclude by highlighting the use of these solution-grown nanowire arrays in dye-sensitized solar cells. The nanowire cells showed an improvement in the charge collection efficiency over traditional nanoparticle cells.

PMID: 16961338 [PubMed]

Piezoelectric and semiconducting coupled power generating process of a single ZnO belt/wire. A technology for harvesting electricity from the environment.

Nano Lett. 2006 Aug;6(8):1656-62

Authors: Song J, Zhou J, Wang ZL

This paper presents the experimental observation of piezoelectric generation from a single ZnO wire/belt for illustrating a fundamental process of converting mechanical energy into electricity at nanoscale. By deflecting a wire/belt using a conductive atomic force microscope tip in contact mode, the energy is first created by the deflection force and stored by piezoelectric potential, and later converts into piezoelectric energy. The mechanism of the generator is a result of coupled semiconducting and piezoelectric properties of ZnO. A piezoelectric effect is required to create electric potential of ionic charges from elastic deformation; semiconducting property is necessary to separate and maintain the charges and then release the potential via the rectifying behavior of the Schottky barrier at the metal-ZnO interface, which serves as a switch in the entire process. The good conductivity of ZnO is rather unique because it makes the current flow possible. This paper demonstrates a principle for harvesting energy from the environment. The technology has the potential of converting mechanical movement energy (such as body movement, muscle stretching, blood pressure), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as flow of body fluid, blood flow, contraction of blood vessels) into electric energy that may be sufficient for self-powering nanodevices and nanosystems in applications such as in situ, real-time, and implantable biosensing, biomedical monitoring, and biodetection.

PMID: 16895352 [PubMed - indexed for MEDLINE]

Evaluation of the antimicrobial activity of each component in Grossman's sealer.

Braz Oral Res. 2006 Apr-Jun;20(2):127-31

Authors: Savioli RN, Pecora JD, Mian H, Ito IY

The antimicrobial activity of Grossman's sealer and its components was evaluated on 13 different strains using the double layer well-diffusion method. Results revealed that Grossman's sealer presented antimicrobial activity against all the tested strains. Among the components of the cement, sodium tetraborate presented the greatest antimicrobial activity, both in type and diameter of the halo and ring of inhibition. Sealer powder, rosin, and eugenol presented similar activity, with no effect on P. aeruginosa and C. albicans. Among these, only eugenol had an effect on E. coli. Zinc oxide was only active against S. sobrinus and E. coli. Barium sulfate and bismuth subcarbonate did not show any antimicrobial effect.

PMID: 16878205 [PubMed - indexed for MEDLINE]

Dietary supplementation with zinc oxide increases Igf-I and Igf-I receptor gene expression in the small intestine of weanling piglets.

J Nutr. 2006 Jul;136(7):1786-91

Authors: Li X, Yin J, Li D, Chen X, Zang J, Zhou X

This study was conducted to investigate the mechanism for the effect of elevated levels of dietary zinc oxide (ZnO) in enhancing the intestinal growth of weanling piglets. In Experiment 1, 4-wk-old (8.1 +/- 0.6 kg) crossbred barrows (n = 36) were assigned randomly to 1 of the 2 dietary groups, with 6 pens/group (3 pigs/pen). One group was fed the basal diet containing 100 mg Zn/kg diet. The other group was fed the basal diet supplemented with ZnO to provide 3000 mg Zn/kg diet. Pigs consumed their feed ad libitum for 14 d. In Experiment 2, 4-wk-old (7.6 +/- 0.16 kg) crossbred barrows (n = 16) were housed individually and assigned to 1 of the 2 dietary groups (8 pigs/group) as in Experiment 1, except that the 2 groups were pair-fed the same amount of feed. At the end of a 14-d treatment period, all of the pigs in both Experiments 1 and 2 were weighed, feed consumption was measured, and blood samples were collected for assays of insulin-like growth factor-I (IGF-I). In addition, 1 pig from each pen in Experiments 1 and 2 was selected randomly to obtain the small-intestinal mucosa for analyzing IGF-I and IGF-I receptor (IGF-IR) gene expression and to determine the small-intestinal morphology. In Experiment 1, dietary supplementation of ZnO increased (P < 0.05) the daily body weight gain and daily feed intake. In Experiment 2, dietary supplementation of ZnO increased (P < 0.05) the daily body weight gain and feed conversion efficiency. In both experiments, the villous height of the small-intestinal mucosa and both the mRNA and protein levels for IGF-I and IGF-IR in the small intestine were markedly enhanced (P < 0.05) by feeding elevated levels of Zn. Serum IGF-I levels did not differ between the control and Zn-supplemental groups in either experiment. Collectively, these results suggest that dietary Zn supplementation exerts its beneficial effects on the intestinal growth of weanling piglets through increasing IGF-I and IGF-IR expression in the small-intestinal mucosa.

PMID: 16772438 [PubMed - indexed for MEDLINE]

Case report: hexachloroethane smoke inhalation: a rare cause of severe hepatic injuries.

Environ Health Perspect. 2006 May;114(5):763-5

Authors: Loh CH, Chang YW, Liou SH, Chang JH, Chen HI

CONTEXT: We report on two patients, a 23-year-old man and a 24-year-old man, who had chemical pneumonitis and respiratory distress after inhaling hexachloroethane/zinc oxide (HC/ZnO) smoke during military training. CASE PRESENTATION: The patients had been healthy previously and denied any history of alcohol or drug abuse. Hematologic tests revealed leukocytosis with neutrophils predominant. The respiratory conditions of both patients improved after steroid therapy and oxygen support, but deterioration of liver function was found. The laboratory results showed that alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase levels were elevated about 1.5-fold the normal limits and that aspartate aminotransferase (AST) levels were marginally elevated. The elevation of liver aminotransferase started from day 1 and day 2 and peaked from day 18 to day 22. ALT/AST levels then returned to normal in 6 weeks. Common viral hepatitis was ruled out after serologic tests. Abdominal sonography and physical examination failed to show any specific findings. DISCUSSION: The hepatotoxic effect was attributed to inhalation of high-concentration HC/ZnO smoke in an enclosed area, where several hepatotoxicants, including ZnCl2, HC, and chlorinated vapors, could have been generated and mixed in the smoke. RELEVANCE TO CLINICAL PRACTICE: These case reports elaborate the hepatic effects that may occur in addition to pulmonary effects of HC/ZnO smoke.

PMID: 16675434 [PubMed - indexed for MEDLINE]

Piezoelectric nanogenerators based on zinc oxide nanowire arrays.

Science. 2006 Apr 14;312(5771):242-6

Authors: Wang ZL, Song J

We have converted nanoscale mechanical energy into electrical energy by means of piezoelectric zinc oxide nanowire (NW) arrays. The aligned NWs are deflected with a conductive atomic force microscope tip in contact mode. The coupling of piezoelectric and semiconducting properties in zinc oxide creates a strain field and charge separation across the NW as a result of its bending. The rectifying characteristic of the Schottky barrier formed between the metal tip and the NW leads to electrical current generation. The efficiency of the NW-based piezoelectric power generator is estimated to be 17 to 30%. This approach has the potential of converting mechanical, vibrational, and/or hydraulic energy into electricity for powering nanodevices.

PMID: 16614215 [PubMed]

[Clinical evaluation of two canal obturation materials in treatment of periapical periodontitis in deciduous teeth]

Shanghai Kou Qiang Yi Xue. 2006 Feb;15(1):107-8

Authors: Song WJ

PURPOSE: To analyze the clinical effects of 283 deciduous teeth which suffered from periapical periodontitis and sinus in 179 children from the year of 2001 to 2004. METHODS: In all the 283 teeth, the root canal of 196 teeth were obturated with paste zinc oxide-eugenal; the other 87 teeth were obturated with Vitapex. The signs,symptoms and radiographs of these teeth were evaluated at 3 and 12 months after treatment. RESULTS: The successful rate was over 96.0% in both treatment groups. CONCLUSIONS: Most of deciduous teeth which suffered from periapical periodontitis and sinus could be preserved if adequate indications were taken and treated in time.

PMID: 16525624 [PubMed - in process]

Efficacy of iron and/or zinc supplementation on cognitive performance of lead-exposed Mexican schoolchildren: a randomized, placebo-controlled trial.

Pediatrics. 2006 Mar;117(3):e518-27

Authors: Rico JA, Kordas K, L&#xF3;pez P, Rosado JL, Vargas GG, Ronquillo D, Stoltzfus RJ

OBJECTIVE: Lead exposure in children has been associated with both global and specific cognitive deficits. Although chelation therapy is advised for children with blood lead concentrations of >44 microg/dL, treatment options for children with lower blood lead values are limited. Because lead absorption is related to children's nutritional status, micronutrient supplements may be 1 strategy for combating low-level, chronic lead exposure. This study was designed to test the efficacy of iron and zinc supplementation for lowering blood lead concentrations and improving cognitive performance in schoolchildren who live in a lead-contaminated city. METHODS: This randomized, double-blind, placebo-controlled field trial was conducted in public elementary schools in Torreón, an industrialized city in northern Mexico. A metal foundry, located close to the city center and within 3.5 km of 9 schools, was the main source of lead exposure. A total of 602 children who were aged 6 to 8 years and regularly attending first grade in the study schools were enrolled. Children were given 30 mg of iron, 30 mg of zinc, both, or a placebo daily for 6 months. A total of 527 completed the treatment, and 515 were available for long-term follow-up, after another 6 months without supplementation. Eleven cognitive tests of memory, attention, visual-spatial abilities, and learning were administered at baseline and each follow-up. RESULTS: There were no consistent or lasting differences in cognitive performance among treatment groups. CONCLUSIONS: Daily supplementation with iron and/or zinc may be of limited usefulness for improving cognition in lead-exposed schoolchildren. However, these treatments may be effective in settings with higher prevalence of nutritional deficiencies or in younger children.

PMID: 16510631 [PubMed - indexed for MEDLINE]

Eating and drinking activity of newly weaned piglets: effects of individual characteristics, social mixing, and addition of extra zinc to the feed.

J Anim Sci. 2006 Mar;84(3):702-11

Authors: Dybkjaer L, Jacobsen AP, T&#xF8;gersen FA, Poulsen HD

In production systems, piglets usually fast for a period after weaning, thereby increasing the risk of diarrhea and a reduction in growth. The low level of eating may relate to insufficient drinking activity, as solid feed intake must be accompanied by water intake. Mixing of newly weaned piglets is a well-known stressor and a common procedure in pig production. The effect of mixing on the temporal development of eating and drinking activity in newly weaned piglets has not been elucidated. High concentrations of zinc (Zn) in the feed improve the health and performance of piglets after weaning, but the underlying mechanisms are still obscure. One possibility is that Zn affects eating and drinking behavior. The effects of mixing 4 littermates from each of 2 litters and adding zinc oxide (ZnO; 2,500 ppm of Zn) to the feed were studied in a 2 x 2 factorial experiment using 123 piglets weaned at 27 d of age. Individual eating and drinking times during the initial 48 h after weaning were analyzed on 2 levels of aggregation, day and hour. The piglets spent less time eating on the first day after weaning compared with the second day (20 +/- 5 vs. 98 +/- 10 min, respectively; P < 0.001), whereas they spent more time drinking on the first day compared with the second day (13 +/- 1 vs. 9 +/- 0.5 min, respectively; P < 0.001). Eating and drinking times were positively associated (P < 0.001). Females ate for longer than males (61 +/- 8 vs. 44 +/- 7 min/24 h, respectively, P = 0.002), whereas sex did not affect drinking time. Drinking time increased (P = 0.003) and eating time decreased (P = 0.001) with increasing preweaning growth rate and weaning weight. Neither mixing nor addition of ZnO affected the daily eating time. However, nonmixed piglets given 2,500 ppm of Zn as ZnO in the feed spent more time drinking per day (12 +/- 1 min) than did nonmixed piglets offered 100 ppm of Zn as ZnO (10 +/- 1 min; P = 0.002). Mixing also affected the hourly distribution of the drinking activity (P < 0.05). In conclusion, the drinking behavior of newly weaned piglets was more affected by the external factors, mixing and addition of ZnO to the feed, than the eating behavior. As eating and drinking are strongly associated, more focus should be paid to the water intake and the interplay between eating and drinking behavior in future studies aiming to reduce weaning problems.

PMID: 16478963 [PubMed - indexed for MEDLINE]

[In vitro evaluation of the sealing ability of an iodoform-calcium phosphorate cement root canal filler]

Shanghai Kou Qiang Yi Xue. 2005 Dec;14(6):621-3

Authors: Ma SF, Chen J, Zhu YQ

PURPOSE: To evaluate the sealing ability of an injectable iodoform-calcium phosphate cement(CPC) root canal filler in vitro. METHODS: Sixty-two single-rooted human extracted teeth were selected and root canals were instrumented to 40# with K file. Fifty-eight teeth were randomly divided into two experimental groups. The root canals were filled by lateral condensation of gutta-purcha with iodoform-CPC or zinc-oxide-eugenol-iodoform paste used as sealer respectively. Other four teeth were used as control. When the sealer was solidified, the apical portion of tooth was soaked into 2% methylene blue for 6 days. After the tooth was longitudinally sectioned, the dye length was measured for apical microleakage.The data obtained were analysed with group t test. RESULTS: The average microleakage in iodoform-CPC group(8.400mm) was significantly larger than that in the control group(5.300mm), P=0.021. CONCLUSIONS: We conclude that iodoform-CPC does not provide a sealing ability as good as zinc-oxide-eugenol-iodoform paste in vitro.

PMID: 16400493 [PubMed - in process]

Early biofilm formation and the effects of antimicrobial agents on orthodontic bonding materials in a parallel plate flow chamber.

Eur J Orthod. 2006 Feb;28(1):1-7

Authors: Chin MY, Busscher HJ, Evans R, Noar J, Pratten J

Decalcification is a commonly recognized complication of orthodontic treatment with fixed appliances. A technology, based on a parallel plate flow chamber, was developed to investigate early biofilm formation of a strain of Streptococcus sanguis on the surface of four orthodontic bonding materials: glass ionomer cement (Ketac Cem), resin-modified glass ionomer cement (Fuji Ortho LC), chemically-cured composite resin (Concise) and light-cured composite resin (Transbond XT). S. sanguis was used as it is one of the primary colonizers of dental hard surfaces. Artificial saliva was supplied as a source of nutrients for the biofilms. The effects of two commercially available mouthrinses (i.e. a fluoride containing rinse and chlorhexidine) were evaluated. Initial colonization of the bacterium was assessed after 6 hours of growth by the percentage surface coverage (PSC) of the biofilm on the disc surfaces. There were statistically significant differences in bacterial accumulation between different bonding materials (P < 0.05), Concise being the least colonized and Transbond XT being the most colonized by S. sanguis biofilms. All materials pre-treated with 0.05 per cent sodium fluoride mouthrinse showed more than 50 per cent reduction in biofilm formation. The 0.2 per cent chlorhexidine gluconate mouthrinse caused significant reduction of biofilm formation on all materials except Ketac Cem. This in vitro study showed that the use of a chemically-cured composite resin (Concise) reduced early S. sanguis biofilm formation. Also, fluoride had a greater effect in reducing the PSC by S. sanguis biofilms than chlorhexidine. Rinsing with 0.05 per cent sodium fluoride prior to placement of orthodontic appliances is effective in reducing early biofilm formation.

PMID: 16373451 [PubMed - indexed for MEDLINE]

The effect of sunscreen on skin elastase activity induced by ultraviolet-A irradiation.

Biol Pharm Bull. 2005 Dec;28(12):2302-7

Authors: Tsukahara K, Moriwaki S, Hotta M, Fujimura T, Sugiyama-Nakagiri Y, Sugawara S, Kitahara T, Takema Y

It has been reported that application of sunscreens prevents the photoaging of skin in animal models and in humans. We irradiated the dorsal skin of hairless mice with ultraviolet-A (UVA), and investigated the effects of sunscreens on skin elastase activity and on skin properties. Six-week-old female HR/ICR hairless mice were used in these experiments. After being treated with either a UVA sunscreen (also containing ultraviolet-B (UVB) sunscreen to eliminate any slight UVB in the UVA lamps; Protection Factor of UVA (PFA)=6, Sun Protection Factor (SPF)=20) or a vehicle, the dorsal skins of mice were irradiated with the UVA lamps at 22.3 J/cm(2)/d, 5 times a week. At the end of 15 weeks skin properties were evaluated and elastase activities were measured. In the vehicle control group, UVA irradiation increased the brightness and yellowing of the skin, decreased the water content of the stratum corneum, increased skin thickness, decreased skin elasticity, increased skin elastase activity, and decreased the ability of the skin to recover in a pinch test, as compared to an unirradiated group. All these differences were statistically significant. In the UVA sunscreen group, both the UVA induced skin damage and the increase in skin elastase activity were significantly inhibited, as compared to the vehicle group. However, as compared to the unirradiated group, skin elastase activity was significantly increased and immediate extensibility of skin (Ue) was significantly decreased, thereby indicating that the UVA sunscreen did not prevent photoaging to the same level as the unirradiated group. These results suggest the partial efficacy of the topical photoprotection from UVA by the sunscreen in inhibiting elastase activation, and also suggest the possibility of reducing photoaging.

PMID: 16327169 [PubMed - indexed for MEDLINE]

Histological analysis of rat dental pulp tissue capped with propolis.

J Oral Sci. 2005 Sep;47(3):135-8

Authors: Sabir A, Tabbu CR, Agustiono P, Sosroseno W

The aim of the present study was to assess the response of rat dental pulp to direct pulp capping with propolis. Flavonoid and non-flavonoid materials were purified from an ethanol extract of propolis obtained from South Sulawesi, Indonesia. A Class I cavity was prepared on the occlusal surface of the right maxillary first molar in Sprague Dawley rats. The dental pulp was exposed and then capped with a zinc oxide-based filler as a control (group I), or with propolis flavonoids (group II) or non-flavonoids (group III). The animals were sacrificed at week 1, 2 or 4, biopsy samples were obtained, and these were stained and viewed by light microscopy. The results showed that pulp inflammation occurred in groups I and III as early as week 1. No dentin bridge formation was seen in these groups. In contrast, there was no evident inflammatory response in group II at week 1. Mild and moderate pulp inflammation in this group occurred at 2 and 4 weeks after treatment, respectively. Partial dentinal bridge formation was seen in group II at week 4. Therefore, the present results suggest that direct pulp capping with propolis flavonoids in rats may delay dental pulp inflammation and stimulate reparative dentin.

PMID: 16313091 [PubMed - indexed for MEDLINE]

Brazilian gutta-percha points. Part I: chemical composition and X-ray diffraction analysis.

Braz Oral Res. 2005 Jul-Sep;19(3):193-7

Authors: Maniglia-Ferreira C, Silva JB, Paula RC, Feitosa JP, Cortez DG, Zaia AA, Souza-Filho FJ

Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP and Dentsply FM) were analysed chemically and by X-ray diffraction, and their chemical compositions were compared. The organic fraction (gutta-percha polymer and wax/resin) of the gutta-percha points was separated from the inorganic fraction (ZnO and BaSO4) by dissolving them in chloroform. The gutta-percha polymer was precipitated with acetone. The inorganic fraction was analysed by elemental microanalysis. Energy-dispersive X-ray microanalysis (EDX) and X-ray diffraction were employed to identify the chemical elements and compounds (barium sulfate and zinc oxide). The barium sulfate content was calculated based on the percentage of sulfur found in the elemental microanalysis. All analyses were repeated three times. The means and standard deviations of the percentage by weight of gutta-percha in the points were: Konne (17.6 +/- 0.30), Tanari (15.2 +/- 0.30), Endopoint (16.7 +/- 0.23), Odous (18.8 +/- 0.20), Dentsply 0.04 (15.7 +/- 0.17), Dentsply 0.06 (16.6 +/- 0.17), Dentsply TP (21.6 +/- 0.15) and Dentsply FM (16.3 +/- 0.23). The means and standard deviations of the zinc oxide content were: Konne (79.9 +/- 0.10), Tanari (81.9 +/- 0.07), Endopoint (81.3 +/- 0.40), Odous (79.7 +/- 0.26), Dentsply 0.04 (77.9 +/- 0.03), Dentsply 0.06 (78.2 +/- 0.07), Dentsply TP (69.8 +/- 0.19) and Dentsply FM (72.6 +/- 0.70). The method utilized was appropriate to quantify gutta-percha, wax/resin, zinc oxide and barium sulfate. Cone brands without barium sulfate were found. An unusual high wax/resin percentage was detected in Dentsply FM (p = 0.0003). Dentsply TP showed the highest gutta-percha percentage.

PMID: 16308607 [PubMed - indexed for MEDLINE]

Effectiveness of 4 pulpotomy techniques--randomized controlled trial.

J Dent Res. 2005 Dec;84(12):1144-8

Authors: Huth KC, Paschos E, Hajek-Al-Khatar N, Hollweck R, Crispin A, Hickel R, Folwaczny M

Pulpotomy is the accepted therapy for the management of cariously exposed pulps in symptom-free primary molars; however, evidence is lacking about the most appropriate technique. The aim of this study was to compare the relative effectiveness of the Er:YAG laser, calcium hydroxide, and ferric sulfate techniques with that of dilute formocresol in retaining such molars symptom-free. Two hundred primary molars in 107 healthy children were included and randomly allocated to one of the techniques. The treated teeth were blindly re-evaluated after 6, 12, 18, and 24 months. Descriptive data analysis and logistic regression analysis, accounting for each patient's effect by a generalized estimating equation (GEE), were used. After 24 months, the following total and clinical success rates were determined (%): formocresol 85 (96), laser 78 (93), calcium hydroxide 53 (87), and ferric sulfate 86 (100). Only calcium hydroxide performed significantly worse than formocresol (p = 0.001, odds ratio = 5.6, 95% confidence interval 2.0-15.5). In conclusion, calcium hydroxide is less appropriate for pulpotomies than is formocresol.

PMID: 16304444 [PubMed - indexed for MEDLINE]

The significance of marginal gap and overextension measurement in the evaluation of the fit of complete crowns.

J Contemp Dent Pract. 2005 Nov 15;6(4):26-37

Authors: Boeckler AF, Stadler A, Setz JM

INTRODUCTION: An important criterion for the success of a crown is marginal fit. However, in the patient's mouth fit can only be evaluated by subjective methods. This study describes the correlation between objective marginal fit and its subjective evaluation by dentists and dental technicians. MATERIALS AND METHODS: Thirty human premolars and molars were randomly divided into six groups and prepared with a shoulder. For each of the six groups, complete crowns were made of different alloys and technologies (casting: AuAgCu, AuPdPt, PdAgAu, CoCrMo, and Ti; milling: Ti). The crowns were cemented with provisional cement. Ten dentists and 10 technicians were asked to evaluate the fit of the crowns with a new dental explorer. The crowns were then cleaned and cemented with a zinc-oxide-phosphate-cement. The marginal gap and a possible overextended margin of the crowns were examined under a special 4x light microscope with a magnification level of 560 X. The means of the gaps and the overextended margins were calculated for each group. Significances were detected by analysis of variance (ANOVA) and the post-hoc-test (Bonferroni, p<0.05). Correlations between objective measuring and subjective evaluation were evaluated using the Pearson test. The influence of the measured values on the subjective evaluation was determined by regression analyses. RESULTS: Crowns made from different alloys and technologies showed partly significantly (p<0.05) different marginal gaps (mean ranging from 35 microm to 92 microm) and significantly (p<0.05) different overextended margins (mean ranging from 40 microm to 149 microm). There were significant correlations (p<0.05) between subjective findings and objective data. Significant correlations (p<0.01) were also found between the subjective findings of dentists and technicians. Compared to the marginal gap, only the overextended margin had a significant influence (p=0.00) on the subjective evaluations of the clinicians. CONCLUSION: Crowns from different alloys and technologies showed differences in marginal fit. Marginal gap and the overextension of the crowns significantly correlated with the subjective evaluation of their fit by dentists and dental technicians. For the decision of the clinicians, whether a crown is acceptable, overextension was more important than marginal gap.

PMID: 16299604 [PubMed - indexed for MEDLINE]

In vitro activity of zinc oxide-eugenol and glass ionomer cements on Candida albicans.

Braz Oral Res. 2005 Apr-Jun;19(2):134-8

Authors: Cassanho AC, Fernandes AM, Oliveira LD, Carvalho CA, Jorge AO, Koga-Ito CY

The aim of this study was to evaluate in vitro the antimicrobial activity of glass ionomer (GIC) and zinc oxide-eugenol (ZOE) cements against Candida albicans. Standardized GIC and ZOE specimens were maintained in contact with C. albicans suspension (1 x 10(6) cells/ml) at 37 degrees C for 24 h, 48 h or 7 days. A control group without any testing cement was included. After the incubation period, aliquots of 0.1 ml were plated on Sabouraud's agar, and then the number of colonies was counted. The results were expressed as values of logarithms of colony-forming units per milliliter (log CFU/mL) and were analyzed statistically by Kruskal-Wallis ANOVA. After 48 h of incubation, the ZOE group presented no growth of C. albicans. GIC and control groups presented similar mean values at all tested periods. According to the results obtained, it could be concluded that, under the experimental conditions, ZOE cement was more effective in vitro against C. albicans than GIC.

PMID: 16292447 [PubMed - indexed for MEDLINE]

Effect of different dye solutions on the evaluation of the sealing ability of Mineral Trioxide Aggregate.

Braz Oral Res. 2005 Apr-Jun;19(2):119-22

Authors: Tanomaru Filho M, Figueiredo FA, Tanomaru JM

Alkaline materials have shown incompatibility with methylene blue dye in leakage experiments. The goal of the present study was to analyze the effect of different dyes on the evaluation of the apical sealing ability of Mineral Trioxide Aggregate root-end fillings. Fifty-six extracted human canines were submitted to root canal instrumentation and obturation. After apical resection, retrograde cavities were prepared and teeth were randomly divided into four experimental (n = 13) and two control groups (n = 2). The following root-end filling materials were used: groups 1 and 2--Pro Root MTA (Dentsply), groups 3 and 4--zinc oxide-eugenol cement (ZOE). Teeth in groups 1 and 3 were immersed in 2% methylene blue solution, while teeth in groups 2 and 4 were immersed in 0.2% rhodamine B in a reduced pressure environment for 48 hours. Teeth were then longitudinally sectioned and leakage was evaluated. Results were submitted to statistical analysis (ANOVA and Tukey's test). Group 1 presented the least leakage (p < 0.05). It was concluded that the evaluation of the sealing ability of MTA is influenced by the dye used, since this material presented better sealing ability when evaluated with Methylene Blue, but was similar to ZOE when evaluated with rhodamine B.

PMID: 16292444 [PubMed - indexed for MEDLINE]

Effects of dietary zinc and iron supplementation on mineral excretion, body composition, and mineral status of nursery pigs.

J Anim Sci. 2005 Dec;83(12):2762-74

Authors: Rincker MJ, Hill GM, Link JE, Meyer AM, Rowntree JE

Two experiments were conducted to evaluate the effects of dietary Zn and Fe supplementation on mineral excretion, body composition, and mineral status of nursery pigs. In Exp. 1 (n = 24; 6.5 kg; 16 to 20 d of age) and 2 (n = 24; 7.2 kg; 19 to 21 d of age), littermate crossbred barrows were weaned and allotted randomly by BW, within litter, to dietary treatments and housed individually in stainless steel pens. In Exp. 1, Phases 1 (d 0 to 7) and 2 (d 7 to 14) diets (as-fed basis) were: 1) NC (negative control, no added Zn source); 2) ZnO (NC + 2,000 mg/kg as Zn oxide); and 3) ZnM (NC + 2,000 mg/kg as Zn Met). In Exp. 2, diets for each phase (Phase 1 = d 0 to 7; Phase 2 = d 7 to 21; Phase 3 = d 21 to 35) were the basal diet supplemented with 0, 25, 50, 100, and 150 mg/kg Fe (as-fed basis) as ferrous sulfate. Orts, feces, and urine were collected daily in Exp. 1; whereas pigs had a 4-d adjustment period followed by a 3-d total collection period (Period 1 = d 5 to 7; Period 2 = d 12 to 14; Period 3 = d 26 to 28) during each phase in Exp. 2. Blood samples were obtained from pigs on d 0, 7, and 14 in Exp. 1 and d 0, 7, 21, and 35 in Exp. 2 to determine hemoglobin (Hb), hematocrit (Hct), and plasma Cu, (PCu), Fe (PFe), and Zn (PZn). Pigs in Exp. 1 were killed at d 14 (mean BW = 8.7 kg) to determine whole-body, liver, and kidney mineral concentrations. There were no differences in growth performance in Exp. 1 or 2. In Exp. 1, pigs fed ZnO or ZnM diets had greater (P < 0.001) dietary Zn intake during the 14-d study and greater fecal Zn excretion during Phase 2 compared with pigs fed the NC diet. Pigs fed 2,000 mg/kg, regardless of Zn source, had greater (P < 0.010) PZn on d 7 and 14 than pigs fed the NC diet. Whole-body Zn, liver Fe and Zn, and kidney Cu concentrations were greater (P < 0.010), whereas kidney Fe and Zn concentrations were less (P < 0.010) in pigs fed pharmacological Zn diets than pigs fed the NC diet. In Exp. 2, dietary Fe supplementation tended to increase (linear, P = 0.075) dietary DMI, resulting in a linear increase (P < 0.050) in dietary Fe, Cu, Mg, Mn, P, and Zn intake. Subsequently, a linear increase (P < 0.010) in fecal Fe and Zn excretion was observed. Increasing dietary Fe resulted in a linear increase in Hb, Hct, and PFe on d 21 (P < 0.050) and 35 (P < 0.010). Results suggest that dietary Zn or Fe additions increase mineral status of nursery pigs. Once tissue mineral stores are loaded, dietary minerals in excess of the body's requirement are excreted.

PMID: 16282614 [PubMed - indexed for MEDLINE]

Comparison of growth performance and zinc absorption, retention, and excretion in weanling pigs fed diets supplemented with zinc-polysaccharide or zinc oxide.

J Anim Sci. 2005 Oct;83(10):2380-6

Authors: Buff CE, Bollinger DW, Ellersieck MR, Brommelsiek WA, Veum TL

Fifty weanling crossbred pigs averaging 6.2 kg of initial BW and 21 d of age were used in a 5-wk experiment to evaluate lower dietary concentrations of an organic source of Zn as a Zn-polysaccharide (Zn-PS) compared with 2,000 ppm of inorganic Zn as ZnO, with growth performance, plasma concentrations of Zn and Cu, and Zn and Cu balance as the criteria. The pigs were fed individually in metabolism crates, and Zn and Cu balance were measured on individual pigs (10 replications per treatment) from d 22 to 26. The basal Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35) diets contained 125 or 100 ppm added Zn as Zn sulfate, respectively, and met all nutrient requirements. Treatments were the basal Phase 1 and 2 diets supplemented with 0, 150, 300, or 450 ppm of Zn as Zn-PS or 2,000 ppm Zn as ZnO. Blood samples were collected from all pigs on d 7, 14, and 28. For pigs fed increasing Zn as Zn-PS, there were no linear or quadratic responses (P > or = 0.16) in ADG, ADFI, or G:F for Phases 1 or 2 or overall. For single degree of freedom treatment comparisons, Phase 1 ADG and G:F were greater (P < or = 0.05) for pigs fed 2,000 ppm Zn as ZnO than for pigs fed the control diet or the diet containing 150 ppm Zn as Zn-PS. For Phase 2 and overall, ADG and G:F for pigs fed the diets containing 300 or 450 ppm of Zn as Zn-PS did not differ (P > or = 0.29) from pigs fed the diet containing ZnO. Pigs fed the diet containing ZnO also had a greater Phase 2 (P < or = 0.10) and overall (P < or = 0.05) ADG and G:F than pigs fed the control diet. There were no differences (P > or = 0.46) in ADFI for any planned comparison. There were linear increases (P < 0.001) in the Zn excreted (mg/d) with increasing dietary Zn-PS. Pigs fed the diet containing ZnO absorbed, retained, and excreted more Zn (P < 0.001) than pigs fed the control diet or any of the diets containing Zn-PS. In conclusion, Phase 2 and overall growth performance by pigs fed diets containing 300 or 450 ppm Zn as Zn-PS did not differ from that of pigs fed 2,000 ppm Zn as ZnO; however, feeding 300 ppm Zn as Zn-PS decreased Zn excretion by 76% compared with feeding 2,000 ppm Zn as ZnO.

PMID: 16160050 [PubMed - in process]

Conversion of zinc oxide nanobelts into superlattice-structured nanohelices.

Science. 2005 Sep 9;309(5741):1700-4

Authors: Gao PX, Ding Y, Mai W, Hughes WL, Lao C, Wang ZL

A previously unknown rigid helical structure of zinc oxide consisting of a superlattice-structured nanobelt was formed spontaneously in a vapor-solid growth process. Starting from a single-crystal stiff nanoribbon dominated by the c-plane polar surfaces, an abrupt structural transformation into the superlattice-structured nanobelt led to the formation of a uniform nanohelix due to a rigid lattice rotation or twisting. The nanohelix was made of two types of alternating and periodically distributed long crystal stripes, which were oriented with their c axes perpendicular to each other. The nanohelix terminated by transforming into a single-crystal nanobelt dominated by nonpolar (0110) surfaces. The nanohelix could be manipulated, and its elastic properties were measured, which suggests possible uses in electromechanically coupled sensors, transducers, and resonators.

PMID: 16151005 [PubMed]

Microbial leakage of Cavit, IRM, and Temp Bond in post-prepared root canals using two methods of gutta-percha removal: an in vitro study.

J Contemp Dent Pract. 2005 Aug 15;6(3):53-61

Authors: Balto H, Al-Nazhan S, Al-Mansour K, Al-Otaibi M, Siddiqu Y

The aim of this study was to evaluate the integrity of the coronal seal of Temp-Bond and compare it to Cavit and IRM after post space preparation using S. faecalis as a microbial tracer. In addition, the affect of two methods of gutta percha removal on the apical seal of root canal fillings was also evaluated. Forty extracted human single rooted teeth were prepared chemomechanically and obturated with gutta percha and AH26 sealer cement using the lateral cold condensation technique to a standardized working length of 15 mm. About 10 mm of the coronal gutta-percha was removed with either Peeso-reamer or a hot plugger. The roots were divided into three experimental groups of 10 roots and a control group. Each experimental group was subdivided equally into two groups of 15 each according to the method of post space preparation. Cavit, IRM, and Temp-Bond were used to seal the access opening. Each root was fixed in a cuvette containing Tryptic Soya Broth which, covered 2 mm of the root apex. Bacterial suspension was introduced through pipette. Fresh bacterial suspension was added every week, and the system was monitored daily for the growth of microorganisms for a period of one month. The results showed there was no significant difference in terms of coronal leakage between the three coronal materials used (P=0.478), but the methods of gutta-percha removal did have an impact on the apical leakage (P=0.047). The mean value showed the Peeso-reamer provided less leakage compared to using a hot plugger during the 30-day experimental time period. It was concluded the temporary type of coronal seal of endodontically treated teeth will not prevent coronal leakage if left for a long period of time. In addition, permanent cementation of the post with the coronal restoration should be carried out as soon as possible to prevent recontamination of the root canal.

PMID: 16127472 [PubMed - indexed for MEDLINE]

Influence of zinc-oxide eugenol, formocresol, and ferric sulfate on bond strength of dentin adhesives to primary teeth.

J Contemp Dent Pract. 2005 Aug 15;6(3):14-21

Authors: Salama FS

This study evaluated in vitro the influence of a temporary filling {zinc oxide-eugenol (ZOE)} and two pulpotomy agents {formocresol (FC) and ferric sulfate (FS)} on shear bond strength (SBS) of two dentin adhesives to the dentin of primary molars. A total of 80 dentin surfaces were prepared and randomly allocated into 10 groups of 8 specimens each. Groups were subjected to different treatments, which included covering with a paste of ZOE mixed at different powder:liquid (P:L) ratios, placement on a gauze soaked in FC or FS, or they received no pretreatment and served as a control. XRV Herculite composite cylinders were bonded to dentin surfaces using Prime and Bond NT adhesive resin or Opti Bond Solo Plus adhesive resin. SBSs were determined using the lnstron testing machine running at a crosshead speed of 0.5 mm/min. The use of ZOE mixed at the lower P:L ratio of 10g:2g significantly decreased the values of SBS of the two adhesives. The use of two pulpotomy agents (FC and FS) significantly decreased the SBS of the two adhesives. The bond strength to dentin of primary teeth was influenced by the pulpotomy agents used and the ZOE P:L ratio but not by the adhesive system used.

PMID: 16127468 [PubMed - indexed for MEDLINE]

Gas adsorption sites in a large-pore metal-organic framework.

Science. 2005 Aug 26;309(5739):1350-4

Authors: Rowsell JL, Spencer EC, Eckert J, Howard JA, Yaghi OM

The primary adsorption sites for Ar and N2 within metal-organic framework-5, a cubic structure composed of Zn4O(CO2)6 units and phenylene links defining large pores 12 and 15 angstroms in diameter, have been identified by single-crystal x-ray diffraction. Refinement of data collected between 293 and 30 kelvin revealed a total of eight symmetry-independent adsorption sites. Five of these are sites on the zinc oxide unit and the organic link; the remaining three sites form a second layer in the pores. The structural integrity and high symmetry of the framework are retained throughout, with negligible changes resulting from gas adsorption.

PMID: 16123294 [PubMed]

Mesosynthesis of ZnO-silica composites for methanol nanocatalysis.

J Am Chem Soc. 2005 Aug 31;127(34):12028-34

Authors: Polarz S, Neues F, van den Berg MW, Gr&#xFC;nert W, Khodeir L

Methanol catalysis meets chemistry under confined conditions. Methanol is regarded as one of the most important future energy sources. ZnO/Cu composite materials are very effective in heterogeneous catalysis for methanol production due to the so-called strong metal-support interaction effect (SMSI). Therefore, materials of superior structural design potentially representing model systems for heterogeneous catalysis are highly desired. Ultimately, such materials could help to understand the interaction between copper and zinc oxide in more detail than currently possible. We report the preparation of nanocrystalline, size-selected ZnO inside the pore system of ordered mesoporous silica materials. A new, liquid precursor for ZnO is introduced. It is seen that the spatial confinement significantly influences the chemical properties of the precursor as well as determines a hierarchical architecture of the final ZnO/SiO(2) nanocomposites. Finally, the ability of the materials to act as model systems in methanol preparation is investigated. The materials are characterized by a variety of techniques including electron microscopy, X-ray scattering, solid-state NMR, EPR, EXAFS, and Raman spectroscopy, and physisorption analysis.

PMID: 16117543 [PubMed]

Influence of apical patency and filling material on healing process of dogs' teeth with vital pulp after root canal therapy.

Braz Dent J. 2005;16(1):9-16

Authors: Holland R, Sant'Anna Júnior A, Souza V, Dezan Junior E, Otoboni Filho JA, Bernabé PF, Nery MJ, Murata SS

The purpose of this study was to investigate the periapical healing process of dogs' teeth with or without apical patency and after root canal filling with two types of sealers. Forty roots of premolars and incisors were utilized. The root canals were over-instrumented and dressed with a corticosteroid-antibiotic solution for 7 days to obtain ingrowth of periapical connective tissue into the canals. After this period, the tissue was removed in half of the specimens (groups with patency) and preserved in the other half (groups without patency). Canals were filled by lateral condensation technique with gutta-percha points and either a calcium hydroxide-based sealer (Sealer Plus) or a Grossman's cement (Fill Canal). The animals were killed by anesthetic overdose 60 days after the endodontic treatment and anatomic pieces were obtained and prepared for histologic examination. Data were evaluated in a blind analysis on the basis of several histomorphologic parameters. The groups without patency had better results (p=0.01) than those in which the ingrown connective tissue was removed. Comparing the sealers, Sealer Plus had significantly better results (p=0.01) than Fill Canal. In conclusion, both the apical patency (presence or absence) and the type of root canal filling material influenced the periapical healing process in dogs' teeth with vital pulp after root canal treatment. The use of a calcium hydroxide-based sealer in teeth without apical patency yielded the best results among the experimental conditions proposed.

PMID: 16113927 [PubMed - indexed for MEDLINE]

Effects of replacing pharmacological levels of dietary zinc oxide with lower dietary levels of various organic zinc sources for weanling pigs.

J Anim Sci. 2005 Sep;83(9):2123-9

Authors: Hollis GR, Carter SD, Cline TR, Crenshaw TD, Cromwell GL, Hill GM, Kim SW, Lewis AJ, Mahan DC, Miller PS, Stein HH, Veum TL,

Two 28-d randomized complete block design experiments were conducted to evaluate the effects of concentrations and sources of Zn on growth performance of nursery pigs. Seven stations participated in Exp. 1, which evaluated the efficacy of replacing 2,500 ppm of Zn from ZnO with 125, 250, or 500 ppm of Zn from Zn methionine. A control diet with 125 ppm of supplemental Zn was included at all stations. A total of 615 pigs were used in 26 replicates. Average weaning age was 20.6 d and the average initial BW was 6.3 kg. There were no differences in any growth response among the three supplemental Zn methionine levels fed in Exp. 1. Zinc supplementation from Zn methionine improved ADG compared with the control during all phases (P < 0.05), due primarily to an increase in ADFI. Pigs fed 2,500 ppm of Zn from ZnO gained faster (P < 0.01) than those fed the control diet during all phases, and faster (P < 0.05) than those fed supplemental Zn from Zn methionine for the 28-d experiment. Differences in gain were again due mainly to differences in feed intake. A second experiment compared five sources of supplemental organic Zn (500 ppm of Zn) with 500 and 2,000 ppm supplemental Zn from ZnO and a control (140 ppm total Zn). Six stations used a total of 624 pigs, with an average weaning age of 20.4 d and averaging 6.2 kg BW in 15 replicates. Pigs fed 2,000 ppm of Zn from ZnO gained faster (P < 0.05) than pigs fed the control or any of the 500 ppm of Zn treatments (ZnO or organic Zn). Pigs fed the 2,000 ppm of Zn from ZnO also consumed more feed than those receiving 500 ppm of Zn from ZnO or from any of the organic Zn sources (P < 0.05). Organic sources of Zn did not improve gain, feed intake, or feed efficiency beyond that achieved with the control diet. Supplemental Zn at a concentration of 500 ppm, whether in the form of the oxide or in an organic form, was not as efficacious for improved ADG as 2,000 to 2,500 ppm of Zn from ZnO.

PMID: 16100067 [PubMed - in process]

Quantitative trait analysis of the development of pulmonary tolerance to inhaled zinc oxide in mice.

Respir Res. 2005;6:73

Authors: Wesselkamper SC, Chen LC, Gordon T

BACKGROUND: Individuals may develop tolerance to the induction of adverse pulmonary effects following repeated exposures to inhaled toxicants. Previously, we demonstrated that genetic background plays an important role in the development of pulmonary tolerance to inhaled zinc oxide (ZnO) in inbred mouse strains, as assessed by polymorphonuclear leukocytes (PMNs), macrophages, and total protein in bronchoalveolar lavage (BAL) phenotypes. The BALB/cByJ (CBy) and DBA/2J (D2) strains were identified as tolerant and non-tolerant, respectively. The present study was designed to identify candidate genes that control the development of pulmonary tolerance to inhaled ZnO. METHODS: Genome-wide linkage analyses were performed on a CByD2F2 mouse cohort phenotyped for BAL protein, PMNs, and macrophages following 5 consecutive days of exposure to 1.0 mg/m3 inhaled ZnO for 3 hours/day. A haplotype analysis was carried out to determine the contribution of each quantitative trait locus (QTL) and QTL combination to the overall BAL protein phenotype. Candidate genes were identified within each QTL interval using the positional candidate gene approach. RESULTS: A significant quantitative trait locus (QTL) on chromosome 1, as well as suggestive QTLs on chromosomes 4 and 5, for the BAL protein phenotype, was established. Suggestive QTLs for the BAL PMN and macrophage phenotypes were also identified on chromosomes 1 and 5, respectively. Analysis of specific haplotypes supports the combined effect of three QTLs in the overall protein phenotype. Toll-like receptor 5 (Tlr5) was identified as an interesting candidate gene within the significant QTL for BAL protein on chromosome 1. Wild-derived Tlr5-mutant MOLF/Ei mice were tolerant to BAL protein following repeated ZnO exposure. CONCLUSION: Genetic background is an important influence in the acquisition of pulmonary tolerance to BAL protein, PMNs, and macrophages following ZnO exposure. Promising candidate genes exist within the identified QTL intervals that would be good targets for additional studies, including Tlr5. The implications of tolerance to health risks in humans are numerous, and this study furthers the understanding of gene-environment interactions that are likely to be important factors from person-to-person in regulating the development of pulmonary tolerance to inhaled toxicants.

PMID: 16026622 [PubMed - indexed for MEDLINE]

Endodontics.

J Am Dent Assoc. 2005 May;136(5):581-2; author reply 582

Authors: Piacine MJ

PMID: 15966645 [PubMed - indexed for MEDLINE]

Influence of dietary zinc oxide and copper sulfate on the gastrointestinal ecosystem in newly weaned piglets.

Appl Environ Microbiol. 2005 May;71(5):2267-77

Authors: H&#xF8;jberg O, Canibe N, Poulsen HD, Hedemann MS, Jensen BB

Dietary doses of 2,500 ppm ZnO-Zn reduced bacterial activity (ATP accumulation) in digesta from the gastrointestinal tracts of newly weaned piglets compared to that in animals receiving 100 ppm ZnO-Zn. The amounts of lactic acid bacteria (MRS counts) and lactobacilli (Rogosa counts) were reduced, whereas coliforms (MacConkey counts) and enterococci (Slanetz counts, red colonies) were more numerous in animals receiving the high ZnO dose. Based on 16S rRNA gene sequencing, the colonies on MRS were dominated by three phylotypes, tentatively identified as Lactobacillus amylovorus (OTU171), Lactobacillus reuteri (OTU173), and Streptococcus alactolyticus (OTU180). The colonies on Rogosa plates were dominated by the two Lactobacillus phylotypes only. Terminal restriction fragment length polymorphism analysis supported the observations of three phylotypes of lactic acid bacteria dominating in piglets receiving the low ZnO dose and of coliforms and enterococci dominating in piglets receiving the high ZnO dose. Dietary doses of 175 ppm CuSO(4)-Cu also reduced MRS and Rogosa counts of stomach contents, but for these animals, the numbers of coliforms were reduced in the cecum and the colon. The influence of ZnO on the gastrointestinal microbiota resembles the working mechanism suggested for some growth-promoting antibiotics, namely, the suppression of gram-positive commensals rather than potentially pathogenic gram-negative organisms. Reduced fermentation of digestible nutrients in the proximal part of the gastrointestinal tract may render more energy available for the host animal and contribute to the growth-promoting effect of high dietary ZnO doses. Dietary CuSO(4) inhibited the coliforms and thus potential pathogens as well, but overall the observed effect of CuSO(4) was limited compared to that of ZnO.

PMID: 15870311 [PubMed - indexed for MEDLINE]

Zinc absorption from zinc oxide, zinc sulfate, zinc oxide + EDTA, or sodium-zinc EDTA does not differ when added as fortificants to maize tortillas.

J Nutr. 2005 May;135(5):1102-5

Authors: Hotz C, DeHaene J, Woodhouse LR, Villalpando S, Rivera JA, King JC

The fortification of staple foods with zinc may play an important role in achieving adequate zinc intakes in countries at risk of zinc deficiency. However, little is known about the relative bioavailability of different zinc compounds that may be used in food fortification. The objective of this study was to measure and compare fractional zinc absorption from a test meal that included a maize tortilla fortified with zinc oxide, zinc sulfate, zinc oxide + EDTA, or sodium-zinc EDTA. A double isotopic tracer ratio method ((67)Zn as oral tracer and (70)Zn as intravenous tracer) was used to estimate zinc absorption in 42 Mexican women living in a periurban community of Puebla State, Mexico. The test meal consisted of maize tortillas, yellow beans, chili sauce, and milk with instant coffee; it contained 3.3 mg zinc and had a phytate:zinc molar ratio of 17. Fractional zinc absorption did not differ significantly between the test groups (ANOVA; P > 0.05). Percent absorptions were (mean +/- SD) zinc oxide, 10.8 +/- 0.9; zinc sulfate, 10.0 +/- 0.02; zinc oxide + EDTA, 12.7 +/- 1.5; and sodium-zinc EDTA, 11.1 +/- 0.7. We conclude that there was no difference in zinc absorption from ZnO and ZnSO(4) when added as fortificants to maize tortillas and consumed with beans and milk. The addition of EDTA with zinc oxide or the use of prechelated sodium-zinc EDTA as fortificants did not result in higher zinc absorption from the test meal.

PMID: 15867288 [PubMed - indexed for MEDLINE]

Comparing inhaled ultrafine versus fine zinc oxide particles in healthy adults: a human inhalation study.

Am J Respir Crit Care Med. 2005 May 15;171(10):1129-35

Authors: Beckett WS, Chalupa DF, Pauly-Brown A, Speers DM, Stewart JC, Frampton MW, Utell MJ, Huang LS, Cox C, Zareba W, Oberd&#xF6;rster G

RATIONALE: Zinc oxide is a common, biologically active constituent of particulate air pollution as well as a workplace toxin. Ultrafine particles (< 0.1 microm diameter) are believed to be more potent than an equal mass of inhaled accumulation mode particles (0.1-1.0 microm diameter). OBJECTIVES: We compared exposure-response relationships for respiratory, hematologic, and cardiovascular endpoints between ultrafine and accumulation mode zinc oxide particles. METHODS: In a human inhalation study, 12 healthy adults inhaled 500 microg/m3 of ultrafine zinc oxide, the same mass of fine zinc oxide, and filtered air while at rest for 2 hours. MEASUREMENTS AND MAIN RESULTS: Preexposure and follow-up studies of symptoms, leukocyte surface markers, hemostasis, and cardiac electrophysiology were conducted to 24 hours post-exposure. Induced sputum was sampled 24 hours after exposure. No differences were detected between any of the three exposure conditions at this level of exposure. CONCLUSIONS: Freshly generated zinc oxide in the fine or ultrafine fractions inhaled by healthy subjects at rest at a concentration of 500 microg/m3 for 2 hours is below the threshold for acute systemic effects as detected by these endpoints.

PMID: 15735058 [PubMed - indexed for MEDLINE]

Ability of fourteen chemical agents used in dental practice to induce chromosome aberrations in Syrian hamster embryo cells.

J Pharmacol Sci. 2005 Jan;97(1):146-52

Authors: Hikiba H, Watanabe E, Barrett JC, Tsutsui T

To assess the genotoxicity of 14 chemical agents used in dental practice, the ability of these agents to induce chromosome aberrations was examined using Syrian hamster embryo (SHE) cells. Statistically significant increases in the frequencies of chromosome aberrations were induced in SHE cells treated with 7 of 10 chemical agents used as endodontic medicaments, that is, carbol camphor, m-cresol, eugenol, guaiacol, zinc oxide, hydrogen peroxide, and formaldehyde. The other 3 chemical agents, that is, thymol, glutaraldehyde, and iodoform, did not increase the levels of chromosome aberrations. Of the 4 chemical agents that are used as an antiseptic on the oral mucosa, chromosome aberrations were induced by iodine, but not by the other 3 antiseptics, benzalkonium chloride, benzethonium chloride, and chlorhexidine. Among the 6 chemical agents exhibiting a negative response in the assay, only thymol induced chromosome aberrations in the presence of exogenous metabolic activation. Our results indicate that chemical agents having a positive response in the present study are potentially genotoxic to mammalian cells and need to be studied further in detail.

PMID: 15665446 [PubMed - indexed for MEDLINE]

Success of an alternative for interim management of irreversible pulpitis.

J Am Dent Assoc. 2004 Dec;135(12):1707-12

Authors: McDougal RA, Delano EO, Caplan D, Sigurdsson A, Trope M

BACKGROUND: Extraction and endodontic therapy are treatment options for irreversible pulpitis. Extraction often is chosen for financial reasons. The authors conducted a study to investigate an alternative interim therapy. METHODS: The authors recruited patients (N = 73) with irreversible pulpitis and whose teeth were restorable but who opted for extraction owing to financial reasons. After undergoing pulpotomy, the teeth were restored by random assignment with one of two intermediate restorative materials: Caulk IRM (Dentsply Caulk, Milford, Del.) (Group I, n = 38) or an IRM base with glass ionomer core (Fuji IX GP, GC America, Alsip, Ill.) (Group II, n = 35). The authors monitored the teeth over six and 12 months for pain, integrity of restoration and radiographic periapical status by densitometric analysis. RESULTS: By six months, 10 percent of subjects remaining in the study (Group I, n = 27; Group II, n = 25) reported pain; by 12 months, 22 percent (Group I, n = 22; Group II, n = 18) reported pain. A two-tailed Fisher exact test showed no significant difference (P > or = .05) between groups at either time interval. No apical radiographic change was noted in 49 percent of teeth at six months (Group I, n = 18; Group II, n = 19) and 42 percent at 12 months (Group I, n = 16; Group II, n = 15). Chi2 analysis demonstrated no significant differences (P > or = .05) between groups. Seven of 22 restorations in Group I and four of 18 in Group II required repair at 12 months with no statistical difference (chi2 analysis, P > or = .05). CONCLUSIONS: The interim treatment of eugenol pulpotomy using either restorative material reliably prevented pain for six months. For longer periods, both restorations may require repair. CLINICAL IMPLICATIONS: This option should preserve the integrity of the arch and extend the use of the tooth while the patient finds the means to finance complete endodontic treatment.

PMID: 15646604 [PubMed - indexed for MEDLINE]

An ex vivo evaluation of resin-modified glass polyalkenoates and polyacid-modified composite resins as orthodontic band cements.

J Orthod. 2004 Dec;31(4):323-8; discussion 301-2

Authors: Knox J, Chye KY, Durning P

OBJECTIVES: The objective of this ex vivo study was to assess the use of resin-modified glass polyalkenoates and polyacid-modified composite resins, as orthodontic band cements. MATERIALS AND METHOD: Plain stainless steel bands were cemented to 350 human extracted third molar teeth using 1 of 7 different cements. Following complete cement cure, half of each sample group was exposed to mechanical stress in a ball mill. Stressed and unstressed samples were tested in tension and the stress at which initial cement failure recorded. The mode of failure was recorded using an adhesive remnant evaluation. RESULTS: The mean band retention stresses offered by the cements studied ranged from 0.96 to 1.56 MPa. Fuji Ortho provided the highest mean band retention stress in "stressed" (1.56 MPa) and "unstressed" (1.45 MPa) states. Exposure to mechanical stress did not appear to significantly influence band retention or mode of cement failure for most cements. Fuji Ortho cement recorded the highest Weibull modulus for all cements tested. Virtually all samples failed at either the cement/enamel or cement band interface. CONCLUSIONS: Significant differences in band displacement stress values and mode of failure were demonstrated between the cements studied. However, generic comparisons were difficult to make.

PMID: 15608348 [PubMed - indexed for MEDLINE]

The pH changes of four different root canal sealers after mixing at various time intervals in vitro.

J Contemp Dent Pract. 2004 Nov 15;5(4):71-8

Authors: Evcil MS, Colak M

The purpose of this study was to compare the surface pH level of four different type sealers after mixing at various time intervals in vitro. After cleaning and shaping root canals in 50 recently extracted, single-rooted human teeth, they were divided into six groups. Each of four groups was obturated with Apexit, N2, Sealapex, and Grossman sealers. The remaining groups served as controls. In group 1 nothing was added to the vial of saline solution. In group 2 canals had been instrumented but not obturated with sealer. The pH level of saline solutions was determined at intervals of 1 hour, 4 hours, 1 day, 2 days, 3 days, 1 week, and 4 weeks after teeth were placed in them. The pH levels of the five solutions were compared to each other and to that of saline solution only.

PMID: 15558092 [PubMed - indexed for MEDLINE]

Na2EDTA enhances the absorption of iron and zinc from fortified rice flour in Sri Lankan children.

J Nutr. 2004 Nov;134(11):3031-6

Authors: Hettiarachchi M, Hilmers DC, Liyanage C, Abrams SA

Rice flour was proposed as a vehicle for iron and zinc fortification in Sri Lanka. Although widely consumed, rice flour has not been evaluated as a fortified food, and the absorption of minerals including iron and zinc from this flour is unknown. Determination of the bioavailability of these nutrients is a critical step before commencing a fortification program. We randomly divided 53 Sri Lankan schoolchildren ages 6-10 y into 4 groups that consumed a local dish prepared with 25 g of fortified rice flour labeled with one of the following: 1) (58)FeSO(4) 2) (58)FeSO(4) + Na(2)EDTA 3) (58)FeSO(4) + (67)ZnO or, 4) (58)FeSO(4) + Na(2)EDTA + (67)ZnO. The levels of iron and zinc were 60 mg/kg; the rice flour also contained folate at 2 mg/kg in each group. Na(2)EDTA was added at a Fe:Na(2)EDTA, 1:1 molar ratio. A total of 48 children completed the trial. Absorption of (58)Fe from a meal was significantly greater (P < 0.01) in the groups administered FeSO(4) + Na(2)EDTA (4.7 +/- 3.6%) than in those administered FeSO(4) without Na(2)EDTA (2.2 +/- 1.3%). Fractional absorption of zinc was 13.5 +/- 6.0% in the FeSO(4) + Na(2)EDTA group and 8.8 +/- 2.0% in the FeSO(4) group (P = 0.037). Although zinc absorption was low, our results demonstrated a benefit in using Na(2)EDTA to improve both iron and zinc absorption. We conclude that the fortification of rice flour is feasible, although additional strategies such as dephytinization or an increase in the level of iron and zinc fortification should be considered to obtain a higher proportion of the daily requirement of total absorbed iron and zinc.

PMID: 15514271 [PubMed - indexed for MEDLINE]

Survey of attitudes, materials and methods employed in endodontic treatment by general dental practitioners in North Jordan.

BMC Oral Health. 2004 Sep 10;4(1):1

Authors: Al-Omari WM

BACKGROUND: General dental practitioners provide the majority of endodontic treatment in Jordan. The aim of this study was to gather information on the methods, materials and attitudes employed in root canal treatment by dentists in North Jordan, in order to evaluate and improve the quality of current practice. METHODS: A questionnaire was posted to all registered general dental practitioners working in private practice in Irbid Governate in North Jordan (n = 181). The questionnaire included information on methods, materials and techniques used in endodontic treatment. RESULTS: Reply rate was 72% (n = 131). The results demonstrated that only five dentists used rubber dam occasionally and not routinely. The majority used cotton rolls for isolation solely or in combination with a high volume saliva ejector (n = 116). The most widely used irrigants were sodium hypochlorite and hydrogen peroxide, which were used by 32.9% (n = 43) and 33.6% (n = 44) of the respondents, respectively. Forty eight percent of the respondents (n = 61) used the cold lateral condensation technique for canal obturation, 31.3% (n = 41) used single cone, 9.9% (n = 13) used vertical condensation and 12.2% (n = 16) used paste or cement only for the obturation. The majority used zinc oxide eugenol as a sealer (72.5%). All, but one, respondents used hand instruments for canal preparation and the technique of choice was step back (52.7%). More than 50% (n = 70) of the dentists took one radiograph for determining the working length, whilst 22.9% (n = 30) did not take any radiograph at all. Most practitioners performed treatment in three visits for teeth with two or more root canals, and in two visits for teeth with a single root canal. CONCLUSIONS: This study indicates that dentists practicing in North Jordan do not comply with international quality standards and do not use recently introduced techniques. Many clinicians never take a radiograph for determining the working length and never used rubber dam or intra-canal medicaments.

PMID: 15361258 [PubMed - as supplied by publisher]