bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Self-etchant Application Time on Bracket Shear Bond Strength
Authors: Ostby Adam Wade , Bishara Samir E. , Laffoon John , Warren John J. 
Published: May 2007

Abstract
Objective: To determine the influence of self-etching primer (SEP) application time on the shear bond strength of orthodontic brackets.
Materials and Methods: Forty human molars were cleaned, mounted, and randomly divided into two groups. The same SEP, adhesive, and brackets were used in both groups. Twenty teeth were conditioned following the manufacturers' recommendations by rubbing the SEP on the enamel surface for 3 to 5 seconds. The remaining 20 teeth were conditioned using the same SEP, but the application time was increased to 15 seconds. The teeth were debonded within half an hour following initial bonding using a universal testing machine. After debonding, the amount of residual adhesive remaining on the tooth was determined. Student's t-test was used to compare the shear bond strength (SBS) of the two groups, and the χ2 test was used to compare the Adhesive Remnant Index (ARI) scores for the two adhesive systems.
Results: The mean SBS of the brackets bonded to the teeth subjected to the SEP for 3 to 5 seconds was 8.0 ± 4.6 MPa and was not significantly different (t = −0.69, P = .494) from the SBS of the brackets bonded using a 15-second SEP application time (x̄ = 8.9 ± 3.4 MPa). The comparisons of the ARI scores between the two groups (χ2 = 2.16) indicated that bracket failure mode was not significantly different (P = .340) for both groups, and most failures were at the bracket-adhesive interface.
Conclusion: The present findings indicate that increasing the SEP application from 3 to 5 seconds to 15 seconds does not result in a significant increase in SBS.
Mandibular Asymmetry in Different Occlusion Patterns
Authors: Sezgin Omer Said , Celenk Peruze , Arici Selim 
Published: May 2007

Abstract
Objective: To investigate the effects of different occlusion types on the mandibular asymmetry in young individuals.
Materials and Methods: Mandibular asymmetry measurements were performed on the panoramic radiographs of 189 subjects (104 females and 85 males; age range, 11–15 years), with different occlusion patterns. The subjects were divided into five groups according to the occlusion types, namely, Angle Class I (Cl I), Class II division 1 (Cl II/1), Class II division 2 (Cl II/2), Class III (Cl III), and normal occlusions. The Kruskal-Wallis test was used to determine the possible statistically significant differences between the groups for condyle, ramus, and condyle-plus-ramus asymmetry index measurements. Identified differences between groups were further analyzed using the Mann-Whitney U-test at the 95% confidence interval (P &lt; .05).
Results: There were no statistically significant differences between male and female subjects. The Kruskal-Wallis test showed that the occlusion type had a significant effect on the condylar asymmetry. In Cl II/1 cases, condylar asymmetry values were significantly different from the values of Cl II/2 and Cl III malocclusion and normal occlusion types. The normal occlusion control group was significantly different from those of Cl II/1 and the Cl I malocclusion groups.
Conclusion: Cl II/1 malocclusion has a significant effect on the condylar asymmetry index when compared to Cl II/2 and Cl III malocclusion and normal occlusion types. However, the mean condylar asymmetry index value in Cl II/1 malocclusion was not different from Cl I malocclusion.
Invisalign and Traditional Orthodontic Treatment Postretention Outcomes Compared Using the American Board of Orthodontics Objective Grading System
Authors: Kuncio Daniel , Maganzini Anthony , Shelton Clarence , Freeman Katherine 
Published: May 2007

Abstract
Objective: To compare the postretention dental changes between patients treated with Invisalign and those treated with conventional fixed appliances.
Materials and Methods: This is a comparative cohort study using patient records of one orthodontist in New York City. Two groups of patients were identified that differed only in the method of treatment (Invisalign and Braces group). Dental casts and panoramic radiographs were collected and analyzed using the objective grading system (OGS) of the American Board of Orthodontics (ABO). The cases were evaluated immediately after appliance removal (T1) and at a postretention time (T2), three years after appliance removal. All patients had completed active orthodontic treatment and had undergone at least one year of retention. A Wilcoxon rank sum test was used to evaluate differences in treatment outcomes between the groups for each of the eight categories in the OGS, including four additional subcategories in the alignment category. A Wilcoxon signed rank test was used to determine the significance of changes within each group from T1 to T2.
Results: The change in the total alignment score in the Invisalign group was significantly larger than that for the Braces group. There were significant changes in total alignment and mandibular anterior alignment in both groups. There were significant changes in maxillary anterior alignment in the Invisalign group only.
Conclusions: In this sample for this period of observation, patients treated with Invisalign relapsed more than those treated with conventional fixed appliances.
Three Cements Used for Orthodontic Banding of Porcelain Molars
Authors: Herion Tracy , Ferracane Jack L. , Covell David A. 
Published: May 2007

Abstract
Objective: Objectives of this study were to (1) compare the mean shear-peel bond strength of orthodontic bands luted to porcelain molar denture teeth with glass ionomer cement (GIC), resin-modified glass ionomer cement (RMGIC), or compomer cement; (2) assess the amount of cement remaining on the teeth after debanding; and (3) compare the survival times of the cemented bands subject to mechanical fatigue.
Materials and Methods: Sixty banded denture teeth (20 per cement group) were used to determine shear-peel bond strength, and 30 banded denture teeth (10 per cement group) were used to determine fatigue survival time. Shear-peel bond strength was determined with a universal testing machine, and groups were compared by one-way analysis of variance. The amount of cement remaining on the teeth after band removal was scored, and a chi-square test was used to compare groups. Fatigue testing was conducted in a ball mill, and a log-rank test was used to compare differences in survival times.
Results: No differences were found in mean shear-peel bond strength among the three groups. The amount of cement remaining on the teeth varied between the compomer and GIC groups (P = .01), with more compomer cement remaining relative to GIC. The mean survival times of bands cemented with compomer or RMGIC were longer than for bands cemented with GIC (P &lt; .001).
Conclusion: The findings show that on porcelain teeth the band cements have comparable mean shear-peel bond strengths, but that band retention with RMGIC and compomer cement are superior to GIC when subjected to simulated mechanical fatigue.
Saliva Contamination Effect on Shear Bond Strength of Self-etching Primer with Different Debond Times
Authors: Turk Tamer , Elekdag-Turk Selma , Isci Devrim , Cakmak Fethiye , Ozkalayci Nurhat 
Published: May 2007

Abstract
Objective: To evaluate shear bond strengths (SBSs) of a self-etching primer (SEP) following saliva contamination at different stages of bonding at debond times of 5, 15, and 30 minutes and 24 hours.
Materials and Methods: Two-hundred forty human premolars were divided into four groups: group 1, uncontaminated; group 2, saliva contamination after priming; group 3, saliva contamination before priming; and group 4, saliva contamination before and after priming. Four subgroups according to debond times of 5, 15, 30 minutes and 24 hours were composed. Metal brackets were bonded with an SEP (Transbond Plus) and light-cure adhesives paste (Transbond XT). SBS values and the adhesive remnants were determined.
Results: The highest SBS was obtained at a debond time of 24 hours for the control group. This was significantly different from the other groups. SBSs at 5, 15, and 30 minutes showed no significant difference from each other in the control group (P &gt; .05). Lowest SBSs were obtained at a debond time of 5 minutes for groups 1, 2, 3, and 4 (8.38, 7.10, 7.06, and 6.26 MPa, respectively) and were not significantly different from each other (P &gt; .05). SBSs at 24 hours were not significantly different from each other for groups 2, 3, and 4 (P &gt; .05). Significant differences were found in the adhesive remnant (P &lt; .001).
Conclusions: SEP (Transbond Plus) may produce clinically acceptable bracket bonding after 5, 15, and 30 minutes from time of placement on the teeth, even with light and heavy saliva contamination.
Acid Resistance of Erbium-doped Yttrium Aluminum Garnet Laser–Treated and Phosphoric Acid–Etched Enamels
Authors: Kim Jung-Ho , Kwon Oh-Won , Kim Hyung-Il , Kwon Yong Hoon 
Published: May 2007

Abstract
Objective: To compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser ablation and of phosphoric acid etching on the in vitro acid resistance of bovine enamel.
Materials and Methods: Teeth were polished to make the surface flat. The polished enamel was either etched with 37% phosphoric acid for 30 seconds or ablated with a single 33 J/cm2 pulse from an Er:YAG laser. The control specimens were free from acid etching and laser ablation. Changes in crystal structure, dissolved mineral (calcium [Ca] and phosphorus [P]) contents, and calcium distribution in the enamel subsurface after a pH-cycling process were evaluated.
Results: After laser treatment, poor crystal structures improved without forming any new phases, such as tricalcium phosphates. Among the tested enamels, dissolved mineral contents were significantly different (P &lt; .05). Er:YAG laser–treated enamels had the lowest mineral dissolution (Ca, 13.78 ppm; P, 6.33 ppm), whereas phosphoric acid–etched enamels had the highest (Ca, 15.90 ppm; P, 7.33 ppm). The reduction rate and reduced depth of calcium content along the subsurface were lowest in Er:YAG laser–treated enamels.
Conclusion: The Er:YAG laser–treated enamels are more acid resistant to acid attack than phosphoric acid–etched enamels.
A Fused Maxillary Central Incisor with Dens Evaginatus as a Talon Cusp
Authors: Danesh Gholamreza , Schrijnemakers Tine , Lippold Carsten , Schäfer Edgar 
Published: May 2007

Abstract
This report presents a rare case of concurrence of dens evaginatus and dental fusion affecting the maxillary right upper central incisor of a 9-year-old male patient. An association of dens evaginatus and dental fusion within the same tooth is rare. In this case, an orthopantomogram, a lateral cephalogram, intraoral radiographs, and a magnetic resonance tomogram were made to obtain a proper diagnosis and to confirm the exact path of the root canals. Because of a forced bite, an orthodontic treatment involving cusp reduction was initiated. During the cusp reduction, no traumatic intraoperative exposure of pulp tissue occurred, and no endodontic or surgical treatment procedures were necessary. After a multibracket treatment, a harmonious integration of the tooth in the upper dental arch was achieved.
Short-term Effect of Mastic Gum on Salivary Concentrations of Cariogenic Bacteria in Orthodontic Patients
Authors: Aksoy Alev , Duran Nizami , Toroglu Serdar , Koksal Fatih 
Published: May 2007

Abstract
Objective: To determine antibacterial activity of chewing mastic gum against the salivary levels of Streptococcus mutans, the total number of viable bacteria, and lactobacilli in patients undergoing therapy with fixed orthodontic appliances.
Materials and Methods: In this study, the levels of S mutans, lactobacilli, and total cultivated bacteria were measured before and after chewing mastic gum. The antibacterial effects of chewing mastic gum against these microorganisms in saliva were compared with a placebo gum. The counts for orthodontically treated patients were evaluated before chewing gum; just after chewing gum; and after 45, 75, 105, and 135 minutes. Saliva samples taken from the patients were inoculated onto trypticase-yeast-cystine-bacitracin agar for mutans streptococci and onto Rogosa agar for lactobacilli. The agar plates were incubated for 48 hours anaerobically at 37°C. The total number of viable bacteria was then counted.
Results: Just after chewing the mastic gum for 15 minutes, a significant decrease of total bacteria and S mutans was observed (P &lt; .001). The reduction in lactobacilli was not significant at later first stage (P &gt; .05). However, at the end of 135 minutes, there were significantly fewer S mutans (P &lt; .001), total viable bacteria (P &lt; .001), and lactobacilli (P &lt; .001) in the oral cavity after chewing mastic gum than after chewing paraffin (P &lt; .001). The results show that chewing mastic gum decreased the total viable bacteria, S mutans, and lactobacilli in saliva in orthodontically treated patients with fixed appliances.
Conclusion: Chewing mastic gum might be useful in preventing caries lesions.
Micropatterned Polypyrrole: A Combination of Electrical and Topographical Characteristics for the Stimulation of Cells
Authors: Gomez N. , Lee J. Y. , Nickels J. D. , Schmidt C. E. 
Published: May 2007

AbstractElectrically conducting polymers such as polypyrrole (PPy) are important biomaterials in neural engineering applications, including neural probes, nerve conduits, and scaffolds for tissue and nerve regeneration. Surface modification of these polymers can introduce other valuable characteristics for neural interfacing in addition to electrical conductivity, such as topographical features and chemical bioactivity. Here, the patterning of PPy to create topographical cues for cells is reported. In particular, 1 and 2 μm wide PPy microchannels are fabricated using electron‐beam (e‐beam) lithography and electropolymerization. A systematic analysis of parameters controlling PPy micropatterning is performed, and finds that microchannel depth, roughness, and morphology are highly dependent on the e‐beam writing current, polymerization current, PPy/dopant concentrations, and the polymerization time. Embryonic hippocampal neurons cultured on patterned PPy polarize (i.e., defined an axon) faster on this modified material, with a twofold increase in the number of cells with axons compared to cells cultured on unmodified PPy. These topographical features also have an effect on axon orientation but do not have a significant effect on overall axon length. This is the first investigation that studies controlled PPy patterning with small dimensions (i.e., less than 5 μm) for biological applications, which demonstrates the relevance of expanding microelectronic materials and techniques to the biomedical field.
A Facile Sol–Gel Strategy for the Synthesis of Rod‐Shaped Nanocrystalline High‐Surface‐Area Lanthanum Phosphate Powders and Nanocoatings
Authors: Rajesh K. , Shajesh P. , Seidel O. , Mukundan P. , Warrier K. G. K. 
Published: May 2007

AbstractSynthesis of rod‐shaped nanocrystalline lanthanum phosphate with an average length of 40 nm even after calcination at 400 °C has been realized through a room‐temperature aqueous sol–gel process. The sol is characterized by particle‐size, zeta‐potential, and viscosity measurements. Gelation of the sol is induced by ammonia. The lanthanum phosphate phase‐formation process is followed by thermal, Fourier‐transform IR, and X‐ray diffraction analysis. Transmission electron microscopy shows that the sol and gel particles have a rod‐shaped morphology and comparable particle sizes. Using the Scherrer equation a crystallite size of 11 nm is obtained for the gel powder calcined at 400 °C and Brunauer–Emmett–Teller (BET) nitrogen‐adsorption analysis showed a high specific surface area of 100 m2 g–1. Ammonia temperature‐programmed desorption measurements show that the density of Lewis acid sites is four times higher than ever reported in the case of lanthanum phosphates. The catalytic activity of the above sample is demonstrated by using it as a Lewis‐acid catalyst in an acetal‐formation reaction with a very good yield of 85 %. The sol is used to develop nanocoatings on a glass surface and the morphology of the coatings is investigated using atomic force microscopy and scanning electron microscopy. The microstructure of the coating confirmed the rod‐shaped nature of the sol particles. The coating was uniform with a thickness of about 55 nm.
Luminescence and Amplified Stimulated Emission in CdSe–ZnS‐Nanocrystal‐Doped TiO2 and ZrO2 Waveguides
Authors: Jasieniak J. , Pacifico J. , Signorini R. , Chiasera A. , Ferrari M. , Martucci A. , Mulvaney P. 
Published: May 2007

AbstractA reproducible route for the preparation of high‐quality CdSe–ZnS‐doped titania and zirconia waveguides is presented. The optical properties of the resultant composite materials are found to be sensitive to the semiconducting properties of the host matrix. Titania‐based composites are seen to be inherently photounstable because of photoelectron injection into the bulk matrix and subsequent nanocrystal (NC) oxidation. In comparison, zirconia composites are significantly more robust with high photoluminescence (PL) retained for annealing temperatures up to 300 °C. Both titania and zirconia composite waveguides exhibit amplified stimulated emission (ASE); however only zirconia‐based waveguides exhibit long‐term photostability (loss of less than 30 % ASE intensity after more than 40 min continuous excitation). We conclude that the low electron affinity of zirconia and its inherent high refractive index makes it an ideal candidate for NC‐based optical waveguides.
Gray/nongray gas radiation modeling in steam cracker CFD calculations
Authors: Stefanidis G. D. , Merci B. , Heynderickx G. J. , Marin G. B. 
Published: May 2007

AbstractA constant composition gray gas and a constant composition nongray gas radiation model are developed and applied in computational fluid dynamic simulations of an industrial scale steam cracking furnace. Both models are based on the exponential wide band model. The gray gas model simplification, commonly used for simulations of industrial applications, is found to have an effect on predicted variable fields like flue gas flow, temperature, and heat flux to the reactor tubes. When the nongray gas model is used, higher energy absorption by the flue gas in the furnace and lower energy transfer to the process gas in the reactor tubes is calculated because of the high absorption coefficients in the strongly absorbing bands of 2.7 and 4.3 μm. Thus, the calculated thermal efficiency increases from 37.5% when using the nongray gas model to 42.6% when using the gray gas model. A 5% difference in the thermal efficiency is large considering the scale and the importance of the process and should be taken into account by the furnace designer. It is also shown that although both models reproduce the basic characteristics of the flow pattern in the furnace, quantitative differences in the flue gas speed are predicted in some regions of the furnace domain. © 2007 American Institute of Chemical Engineers AIChE J, 2007
The accuracy of activated partial thromboplastin times when drawn through a peripherally inserted central catheter
Authors: Rondina Matthew T. , Markewitz Boaz , Kling Stephen J. , Nohavec Robert , Rodgers George M. 
Published: May 2007

AbstractThe peripherally‐inserted central catheter (PICC) is used commonly in hospitalized patients. The presence of heparin within the PICC lumen, however, may affect the results of coagulation indices when measured on blood drawn through it. In 41 patients with a PICC inserted as part of their medical care, we compared activated partial thromboplastin times (aPTTs) measured on blood drawn through the PICC to blood drawn through a peripheral venipuncture (VP). There were no clinically significant differences between aPTT values from the two samples. Using the PICC to obtain blood for the measurement of aPTT is accurate and may reduce the need for peripheral VPs. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
The use of desmopressin as a hemostatic agent: A concise review
Authors: Franchini Massimo 
Published: May 2007

AbstractDesmopressin, a synthetic derivative of the antidiuretic hormone vasopressin, is the treatment of choice for most patients with von Willebrand disease and mild hemophilia A. Moreover, the compound has been shown to be useful in a variety of inherited and acquired hemorrhagic conditions, including some congenital platelet function defects, chronic liver disease, uremia, and hemostatic defects induced by the therapeutic use of antithrombotic drugs such as aspirin and ticlopidine. Finally, desmopressin has been used as a blood saving agent in patients undergoing operations characterized by large blood loss and transfusion requirements, but studies suggest that this is not as effective as other methods. This review briefly summarizes the current clinical indications on the use of desmopressin as a hemostatic agent. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Prevention of red cell alloimmunization by CD25 regulatory T cells in mouse models
Authors: Yu Jin , Heck Susanne , Yazdanbakhsh Karina 
Published: May 2007

AbstractTransfusion therapy is currently an effective therapeutic intervention in a number of diseases, including sickle cell disease. However, its use is complicated by a high incidence of red blood cell (RBC) alloimmunization in the transfusion recipients. The identification of T regulatory cells (Tregs) among the CD4+ CD25+ T cell subset as key regulators of peripheral tolerance in mice as well as humans has opened an exciting era in the prevention and treatment of autoimmune disease and for improving organ transplantation. However, their potential in inducing transfusion tolerance remains to be explored. We used red cells from mice transgenic for human glycophorin A blood group antigen as donor cells and transfused wild‐type mice to induce alloantibodies, as an experimental system to study RBC alloimmunization. We found that depletion with anti‐CD25 enhanced the alloantibody production, indicating that CD25 Tregs play an important role in regulation of alloantibody responses. More importantly, adoptive transfer of purified population of CD4+CD25+ but not CD4+CD25− cells from naïve mice prevented the induction of IgG and IgM alloantibody production in transfusion recipients, with a concomitant reduction in activated splenic B cells and macrophages. Similarly, adoptive transfer of purified populations of CD4+CD25+ cells from naïve mice into naïve syngeneic recipients inhibited the anti‐Ig response to rat RBCs in the recipients but transfer of control CD4+CD25− cells did not. Altogether, our results demonstrate that Tregs participate in the control of transfusion‐associated RBC alloantibody responses, opening up the possibility that Treg immunotherapy may be exploited for suppressing transfusion immunization events. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.