bluuebunny/crossref_metadata_2025 huggingface dataset:
Microwave Dielectric Ceramics in Li2O–Bi2O3–MoO3 System with Ultra‐Low Sintering Temperatures
Authors: Zhou Di , Randall Clive A. , Wang Hong , Pang Li‐Xia , Yao Xi
Published: January 2010

A series of compounds in the Li2O–Bi2O3–MoO3 ternary system were investigated with regard to the preparation, phase composition, microwave dielectric properties, and chemical compatibility with silver (Ag) and aluminum (Al) electrodes. All the ceramics in this work have sintering temperatures lower than 750°C. The sintering behaviors and microwave dielectric properties of three single phases Li2MoO4, (Li0.5Bi0.5)MoO4, and Li8Bi2Mo7O28 bulk ceramics, were of particular focus in this investigation. The Li2MoO4 ceramic can be sintered to a high density at 540°C/2 h with a relative permittivity ∼5.5, a Q×f value of 46 000 GHz, and a temperature coefficient of resonant frequency (TCF) of ∼−160 ppm/°C. The (Li0.5Bi0.5)MoO4 ceramic has a scheelite structure and the largest relative permittivity of 44.4 among the ceramics studied in this work with a sintering temperature around 560°C, a Q×f value of 3200 GHz, and a large positive TCF of ∼+245 ppm/°C. The Li8Bi2Mo7O28 ceramic could be sintered at 540°C and has a relative permittivity of 13.6, a Q×f value of 8000 GHz, and a small negative TCF value of ∼−59 ppm/°C. From the X‐ray diffraction analysis of cofired ceramics, the Li2MoO4 ceramic does not react with either Ag or Al powders. The Li8Bi2Mo7O28 ceramic reacts with Ag but not with Al at its densification temperature. The (Li0.5Bi0.5)MoO4 ceramic was found to strongly react with Ag powder and to a limited extent with Al powders. From this study, the Li2O–Bi2O3–MoO3 ternary system has a number of attractive new materials with low sintering temperatures, high‐performing microwave dielectric properties, chemical compatibility with both Ag and Al metal electrodes, nontoxicity, and low‐cost constituents. All these materials can be included in the new field of ultra‐low‐temperature cofiring dielectrics for multilayer applications.
Polymer‐Derived Silicon Oxycarbide/Hafnia Ceramic Nanocomposites. Part II: Stability Toward Decomposition and Microstructure Evolution at T≫1000°C
Authors: Ionescu Emanuel , Papendorf Benjamin , Kleebe Hans‐Joachim , Riedel Ralf
Published: January 2010

This study presents first investigations on the high‐temperature stability and microstructure evolution of SiOC/HfO2 ceramic nanocomposites. Polymer‐derived SiOC/HfO2 ceramic nanocomposites have been prepared via chemical modification of a commercially available polysilsesquioxane by hafnium tetra (n‐butoxide). The modified polysilsesquioxane‐based materials were cross‐linked and subsequently pyrolyzed at 1100°C in argon atmosphere to obtain SiOC/HfO2 ceramic nanocomposites. Annealing experiments at temperatures between 1300° and 1600°C were performed and the annealed materials were investigated with respect to chemical composition and microstructure. The ceramic nanocomposites presented here were found to exhibit a remarkably improved thermal stability up to 1600°C in comparison with hafnia‐free silicon oxycarbide. Chemical analysis, X‐ray diffraction, FTIR, and Raman spectroscopy as well as electron microscopy (SEM, TEM) studies revealed that the excellent thermal stability of the SiOC/HfO2 nanocomposites is a consequence of the in situ formation of hafnon (HfSiO4), which represents a concurrent reaction to the carbothermal decomposition of the SiOC matrix. Thus, by the annealing of SiOC/HfO2 materials at 1600°C, novel HfSiO4/SiC/C ceramic nanocomposites can be generated. The results presented emphasize the potential of these materials for application at high temperatures.
Anisotropic Thermal Diffusivity and Conductivity of La‐Doped Strontium Niobate Sr2Nb2O7
Authors: Sparks Taylor D. , Fuierer Paul A. , Clarke David R.
Published: January 2010

The thermal diffusivity of the La‐doped layered perovskite Sr2Nb2O7 parallel and perpendicular to the perovskite layers is reported from room temperature up to 1000°C. The anisotropy persists through an incommensurate‐normal ferroelectric phase transformation at 215°C and up to 1000°C, the maximum temperature of our measurements. The thermal conductivity perpendicular to the perovskite layers, derived from the diffusivity in the same direction, calculated using the density and measured heat capacity, has a constant value of 1.05±0.05 W/mK up to 1000°C. Possible explanations for the low thermal conductivity and anisotropy are described.
A Combustion Method to Synthesize a Belite Cement Clinker
Authors: Zapata Aída , Bosch Pedro
Published: January 2010

The calcination method is the usual method to synthesize cement clinkers. The production of ordinary Portland cement requires temperatures as high as 1450°C. High amounts of energy are used and huge flows of carbon dioxide are liberated to the atmosphere. In the literature, the combustion method has been often reported as a fast and effective method to prepare ceramics. The precursor solutions are metal nitrates and organic combustibles such as urea or glycine. The oxidation–reduction exothermic reaction is very fast. In this work, the effect of H2O2 addition to the combustion preparation of clinker is discussed. A conventional clinker prepared by calcinations at 1200°C is used for comparison purposes. The combustion preparation with H2O2 as an additive reduces calcination time and temperature.
Direct Observation of A‐Site Vacancies and a Twin Boundary Structure in La2/3TiO3‐Based Ceramics Using HAADF/STEM
Authors: Azough Feridoon , Freer Robert , Schaffer Bernhard
Published: January 2010

Ceramics of 0.9La2/3TiO3–0.1LaAlO3 prepared by the mixed oxide route were sintered at 1400°C in air for 4 h and cooled at rates 180°–1°C/h. The products were at least 97% dense with grain sizes of 7–10 μm and relative permittivities 66.9±0.7 at 4 GHz. Rapidly cooled samples (180°C/h) were single phase and exhibited the highest dielectric Q×f values of 16 300±900 GHz. High‐resolution transmission electron microscopy revealed microtwins and domains in all the ceramics, with the highest density of both features in the rapidly cooled samples. A‐site vacancies in rapidly cooled 0.9La2/3TiO3–0.1LaAlO3 ceramics were imaged by aberration‐corrected scanning transmission electron microscopy. It is shown that vacancies and La1 atoms occupy the 4(h) sites and the 4(g) site is fully occupied by La2 atoms in the orthorhombic Cmmm structure of lanthum titanate. The microtwin boundaries in the microstructure of La2/3TiO3 stabilized by LaAlO3 lie on the La2 atomic planes. On twinning, La2 and La1 atoms share the same site. The sharing of the 4(h) and 4(g) atomic sites at the twin boundaries is a mechanism to reduce lattice strain upon the continuous transformation from a high‐temperature simple cubic Fm3m form to a low‐temperature orthorhombic Cmmm form, which involves vacancy/cation ordering and anti‐phase tilting of the oxygen octahedra.
Effect of Annealing Temperature and Dopant Concentration on the Conductivity Behavior in (DyO1.5)x–(WO3)y–(BiO1.5)1−x−y
Authors: Jung Doh Won , Duncan Keith L. , Camaratta Matthew A. , Lee Kang Taek , Nino Juan C. , Wachsman Eric D.
Published: January 2010

Cubic‐stabilized ((DyO1.5)x–(WO3)y–(BiO1.5)1−x−y) electrolytes (DWSB) having higher conductivity than (ErO1.5)0.2 (BiO1.5)0.8 (20ESB) were developed. However, this DWSB composition also experienced a conductivity degradation like other cubic stabilized bismuth oxides in intermediate temperature (IT) ranges, i.e. 500°–700°C. Several DWSB compositions with the same 2:1 dopant content ratio (Dy:W) were annealed to determine the conductivity behavior in the IT range with time. All DWSB compositions maintained their initial conductivity at 700°C, but underwent conductivity degradation at ≤600°C. The effect of total dopant concentration on the conductivity degradation behavior was investigated at 600° and 500°C. It was also found that 8D4WSB, which is the highest conductivity composition, has promise as an electrolyte for an isothermal operation above 650°C or below 400°C.
Electrical and Mechanical Properties of Fine‐Grained Li/Ta‐Modified (Na,K)NbO3‐Based Piezoceramics Prepared by Spark Plasma Sintering
Authors: Shen Zong‐Yang , Li Jing‐Feng , Wang Ke , Xu Siyang , Jiang Wan , Deng Qihuang
Published: January 2010

Dense and fine‐grained (Na0.535K0.485)1−xLix(Nb0.8Ta0.2)O3 (x=0.02–0.07) (abbreviated as NKLxNT) lead‐free piezoceramics were fabricated by spark plasma sintering (SPS), followed by postannealing in air. All the NKLxNT ceramics showed single perovskite structures with a phase transition from an orthorhombic symmetry to a tetragonal one across a composition region of 0.04<x<0.05. The sample with a composition of x=0.05 had the maximum values of piezoelectric coefficient (d33=243 pC/N) and planar electromechanical coupling coefficient (kp=46.1%), and other good properties such as Qm=85, ɛr=1240, and tg δ=0.023. Because of the enhanced densification and refined microstructure, the SPS‐processed NKLxNT ceramics also had better fracture strength than that prepared by normal sintering.
Crystal Structure and Theoretical Elastic Property of a New Ternary Ceramic HfAl4C4
Authors: Nian Hongqiang , He Lingfeng , Li Fangzhi , Wang Jingyang , Zhou Yanchun
Published: January 2010

HfAl4C4, a new ternary aluminum carbide, was discovered and its crystal structure was determined by a combination of X‐ray diffraction, transmission electron microscopy, and first‐principles calculations. The crystal structure is trigonal belonging to thespace group. The refined lattice constants area=0.3308 nm,c=2.190 nm. First‐principles method was used to calculate the theoretical second‐order elastic constants, bulk modulus, shear modulus, and the Young's modulus of HfAl4C4. It shows that HfAl4C4has relatively high elastic stiffness.
Ba4LiNb3−xTaxO12 (x=0–3): A Series of High‐Q Microwave Dielectrics from the Twinned 8H Hexagonal Perovskites
Authors: Fang Liang , Li Chunchun , Peng Xiyang , Hu Changzheng , Wu Bolin , Zhou Huangfu
Published: January 2010

A series of the twinned 8H hexagonal perovskites in the Ba4LiNb3−xTaxO12 (x=0–3) system were synthesized by the conventional solid‐state reaction method. Ba4LiNb3−xTaxO12 solid solutions were single phase in the whole range of x values. The ceramics exhibit perfect microwave dielectric properties with relative permittivity, ɛr∼28–37, high quality factor, Q×f∼37 000–104 000 GHz, and temperature coefficient of resonant frequency, τf∼+25–+65 ppm/°C.
Photo‐Physical Behaviors of Efficient Green Phosphor Ba2MgSi2O7:Eu2+ and Its Application in Light‐Emitting Diodes
Authors: Zhang Xinguo , Zhang Jilin , Wang Rui , Gong Menglian
Published: January 2010

An efficient green phosphor, Ba2MgSi2O7:Eu2+, was prepared by a solid‐state reaction. Excited by 350–420 nm light, the phosphor shows a strong and broad emission band centering at 505 nm. The concentration quenching mechanism was verified to be a dipole–dipole interaction and the critical energy‐transfer distance was confirmed as around 20 Å by both the calculated crystal structure method and the experimental spectral method. This phosphor shows a low thermal‐quenching property with an activation energy of 0.677 eV. Light‐emitting diodes (LEDs) were fabricated with Ba2MgSi2O7:0.07Eu2+ and 395‐nm‐emitting InGaN chips and exhibited strong wide‐band green emission and relatively stable current‐dependent electroluminescence properties, indicating that this phosphor is a promising candidate as a green component for the fabrication of white LEDs.
Characterization of 0.7Bi(Fe0.9Cr0.1)O3–0.2PbTiO3–0.1BaTiO3 Multiferroic Ceramics Derived from Sol–Gel
Authors: Liu Xiao‐Hui , Xu Zhuo , Wei Xiao‐Yong , Yao Xi
Published: January 2010

A 0.7Bi(Fe0.9Cr0.1)O3–0.2PbTiO3–0.1BaTiO3 (BFC–PT–BT) solid solution was fabricated using an aqueous sol–gel method. The dielectric, ferroelectric, piezoelectric, and ferromagnetic properties of the sol–gel‐derived BFC–PT–BT ceramics were investigated. A remanent polarization of 11.1 μC/cm2 and a coercive field of 22.5 kV/cm were obtained. The piezoelectric coefficient d33 was 45 pC/N at 30 kV/cm, 120°C. The planar electromechanical coupling factor Kp was 24%. The spontaneous and remanent magnetizations of BFC–PT–BT were 0.75 and 0.7 emu/g, respectively.
Influence of Mn Doping on the Structure and Properties of Na0.5Bi0.5TiO3 Single Crystals
Authors: Ge Wenwei , Li Jiefang , Viehland Dwight , Luo Haosu
Published: January 2010

Lead‐free ferroelectric single crystals of Na0.5Bi0.5TiO3 (NBT) and Mn‐doped Na0.5Bi0.5TiO3 (Mn:NBT) have been grown by a top‐seeded‐solution growth method. The Mn concentration in the as‐grown Mn:NBT crystal was determined to be 0.24 at.% by analytical analysis. X‐ray diffraction studies revealed that both crystals had a phase transformational sequence of cubic (C)→tetragonal (T)→rhombohedral (R) on cooling, although the transition temperatures were decreased slightly by Mn doping. Polarized light microscopy images revealed that ferroelastic domains remained present below the T→R phase boundary into the R phase field at room temperature for both NBT and Mn:NBT, although the ferroelastic domain size was decreased by a factor of ∼2 × by Mn. We also found that the piezoelectric, ferroelectric and dielectric properties were enhanced in the R phase field by Mn.
Glass Strengthening Via High‐Intensity Plasma‐Arc Heating
Authors: Wereszczak Andrew A. , Harper David C. , Duty Chad E. , Patel Parimal
Published: January 2010

A high‐intensity plasma‐arc lamp was used to irradiate the surface of soda–lime silicate glass tiles to determine whether an increase in strength could be achieved. The lamp has a maximum power density of 3500 W/cm2, a processing area of 2 cm × 10 cm, a broad‐spectrum energy distribution between 0.2 and 1.4 μm, and was controlled to unidirectionally sweep across 50 mm2 tiles at a constant speed of 8 mm/s. Ring‐on‐ring (RoR) equibiaxial flexure and four‐point unidirectional flexure testings of entire tiles were used to measure and compare uncensored and unimodal Weibull failure stress distributions of treated and untreated glass. Even under nonoptimized processing conditions, the RoR Weibull characteristic failure stress increased by approximately 25% and the four‐point‐bend Weibull characteristic failure stress increased by approximately 65%. Additionally, the failure stresses of the weakest samples of the heat‐treated glass were significantly higher than those of the untreated glass. Strengthening was due to a fire‐polishing‐like mechanism. The arc‐lamp heat treatment caused the location of the strength‐limiting flaws in the four‐point‐bend tiles to change; namely, failure initiation occurred on the gauge section surface for the treated glass, whereas it occurred at a gauge section edge for the untreated glass. Arc‐lamp heat treatment is attractive not only because it provides strengthening, but because it can (noncontact) process large amounts of glass quickly and inexpensively, and is a process that either a glass manufacturer or an end‐user can readily use.
Soft Solution Processing for the Synthesis of Alumina Nanoparticles in the Presence of Glucose
Authors: Naskar Milan Kanti
Published: January 2010

Alumina nanoparticles were synthesized following hydrothermal process at 170°C for 6 h, using glucose and other water‐based precursor materials. The uncalcined and calcined (550°–1200°C) particles were characterized by differential thermal analysis, thermogravimetry, Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and multipoint Brunauer–Emmett–Teller (BET) surface area. The microstructures of the calcined (at 550°C) particles were examined by field‐emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD and FTIR studies revealed that gamma‐alumina (γ‐Al2O3) persisted up to 1000°C followed by the appearance of alpha‐alumina (α‐Al2O3) at 1200°C. BET surface area analysis confirmed that the specific surface area of γ‐Al2O3 was higher compared with α‐Al2O3. Because of particle agglomeration, the crystallite sizes obtained by the BET method showed larger values than those determined by the XRD method for the samples calcined at 550°–1200°C. For 550°C‐treated sample, FESEM micrograph showed the aggregated particles of size 20–80 nm, while TEM image of the same sample revealed a particle size of 5–10 nm.
High Thermal Stability and Photoluminescence of Si–N‐Codoped BaMgAl10O17:Eu2+Phosphors
Authors: Wang YiFei , Xu Xin , Yin LiangJun , Hao LuYuan
Published: January 2010

The luminance degradation of BaMgAl10O17:Eu2+(BAM) caused by baking at 600°C was studied. The dissolution of Si–N into BAM lattice lead to only a reduction in the lattice parameters. Under UV excitation, the Si–N codoping enhanced the luminescent intensity by a factor of 110% for the as‐received phosphors and by a factor of 122% for phosphors baked at 600°C for 1 h. This could be attributed to the stable local structure surrounding the Eu2+ions and the lower electronegativity of nitrogen. The proposed method is expected to be potentially applicable to other aluminate phosphors with higher stability and photoluminescence.
Modulation of platelet activation and initial cytokine release by alloplastic bone substitute materials
Authors: Klein M. O. , Kämmerer Peer W. , Scholz Thomas , Moergel Maximilian , Kirchmaier Carl Maximilian , Al‐Nawas Bilal
Published: January 2010

Objectives: Platelet‐derived cytokines play a crucial role in tissue regeneration. In regenerative dental medicine, bone substitute materials (BSM) are widely used. However, initial interactions of BSM and platelets are still unknown. The aim of this study was to evaluate the potential of platelet activation and subsequent initial cytokine release by different commercial alloplastic BSM.

Material and methods: Eight commercial BSM of different origins and chemical compositions (tricalcium phosphate, hydroxyapatite, bioactive glass: SiO2 and mixtures) were incubated with a platelet concentrate (platelet‐rich plasma, PRP) of three healthy volunteers at room temperature for 15 min. Platelet count, aggregation, degranulation (activated surface receptor CD62p) and cytokine release (Platelet‐derived growth factor, Vascular endothelial growth factor) into the supernatant were quantified. Highly thrombogenic collagen served as a reference.

Results: The investigated PRP samples revealed different activation patterns when incubated with different BSM. In general, SiO2‐containing BSM resulted in high platelet activation and cytokine release. In detail, pure bioactive glass promoted platelet activation most significantly, followed by hybrid BSM containing lower ratios of SiO2. Additionally, we found indications of cytokine retention by BSM of large specific surfaces.

Conclusions: Platelet activation as well as consecutive storage and slow release of platelet‐derived cytokines are desirable attributes of modern BSM. Within the limits of the study, SiO2‐containing BSM were identified as promising biomaterials. Further investigations on cytokine adsorption and cytokine release kinetics by the respective BSM have to be conducted.

To cite this article:
 Klein MO, Kämmerer PW, Scholz T, Moergel M, Kirchmaier CM, Al‐Nawas B. Modulation of platelet activation and initial cytokine release by alloplastic bone substitute materials. Clin. Oral Impl. Res. 21, 2010; 336–345 doi: 10.1111/j.1600‐0501.2009.01830.x
Osseointegration of one‐piece zirconia implants compared with a titanium implant of identical design: a histomorphometric study in the dog
Authors: Koch F. P. , Weng D. , Krämer S. , Biesterfeld S. , Jahn‐Eimermacher A. , Wagner W.
Published: January 2010

Objective: The aim of this study was to evaluate osseointegration of one‐piece zirconia vs. titanium implants depending on their insertion depth by histomorphometry.

Material and methods: Four one‐piece implants of identical geometry were inserted on each side of six mongrel dogs: (1) an uncoated zirconia implant, (2) a zirconia implant coated with a calcium‐liberating titanium oxide coating, (3) a titanium implant and (4) an experimental implant made of a synthetic material (polyetheretherketone). In a split‐mouth manner they were inserted in submerged and non‐submerged gingival healing modes. After 4 months, dissected blocks were stained with toluidine blue in order to histologically assess the bone‐to‐implant contact (BIC) rates and the bone levels (BL) of the implants.

Results: All 48 implants were osseointegrated clinically and histologically. Histomorphometrically, BL in the crestal implant part did not differ significantly with regard to material type or healing modality. The submerged coated zirconia implants tended to offer the most stable crestal BL. The histometric results reflected the different healing modes by establishing different BL. The median BIC of the apical implant part of the zirconia and titanium group amounted to 59.2% for uncoated zirconia, 58.3% for coated zirconia, 26.8% for the synthetic material and 41.2% for titanium implants.

Conclusions: Within the limits of this animal study, it is concluded that zirconia implants are capable of establishing close BIC rates similar to what is known from the osseointegration behaviour of titanium implants with the same surface modification and roughness.

To cite this article:
 Koch FP, Weng D, Krämer S, Biesterfeld S, Jahn‐Eimermacher A, Wagner W. Osseointegration of one‐piece zirconia implants compared with a titanium implant of identical design: a histomorphometric study in the dog. Clin. Oral Impl. Res. 21, 2010; 350–356. doi: 10.1111/j.1600‐0501.2009.01832.x
Transference of virtual planning and planning over biomedical prototypes for dental implant placement using guided surgery
Authors: Viegas Vinicius Nery , Dutra Vinicius , Pagnoncelli Rogério Miranda , De Oliveira Marília Gerhardt
Published: January 2010

Objectives: This study evaluated the transference of virtual planning and planning over biomedical prototypes for dental implant placement using guided surgery.

Material and methods: This experiment was conducted with 11 identical replicas of a human edentulous mandible. For each mandible, models and surgical guides were manufactured using stereolithography. Simulated surgeries were performed on the prototypes. Following this, the implants were placed in the mandible replicas. Superposition of the tridimensional pre‐ and postoperative models was used for virtual evaluation. The real evaluation was conducted by linear measurements directly on the models.

Results: The variations in angles and distances between the coronal, central and apical regions of the 22 implants evaluated in this study had mean values <1.45° and 0.41 mm. The correlations between the positions of implant beds in each mandible were fair to very good, according to the distance analyzed and the interpretation guidelines used.

Conclusions: According to the results of this study, the variations found in the transference of dental implant positioning to the operative field, determined during virtual planning and obtained in surgeries simulated with biomedical prototypes, confirm the reliability of guided surgery techniques in implantology.

To cite this article:
 Viegas VN, Dutra V, Pagnoncelli RM, de Oliveira MG. Transference of virtual planning and planning over biomedical prototypes for dental implant placement using guided surgery. Clin. Oral Impl. Res. 21, 2010; 290–295. doi: 10.1111/j.1600‐0501.2009.01833.x
Tolerance within a surgical guide
Authors: Van Assche N. , Quirynen M.
Published: January 2010

Background: Recently, guided surgery has been introduced and several papers verified its accuracy.

Aim: While those studies reported on the accuracy of the entire procedure, this experiment wanted to make clinicians aware of the amount of the deviation that can already occur during the drilling procedure alone, due to the tolerance of the drill in the drill key.

Material and methods: Drilling was executed in plexi‐glass with a maximal inclination of the drills within the drill keys.

Results: A mean deviation in angulation of 4.7° occurred with a mean horizontal deviation at the implant shoulder of 0.8 mm and 1.8 mm at the apex of 13 mm implant. The deviation was further dependent of the implant length, the distance of the sleeve above the bone and the respective guiding system.

Discussion: Increasing the height of the drill key will minimize the inaccuracy.

Conclusions: The results from this experiment showed the importance of keeping the drill parallel to the guide in a centric position.

To cite this article:
 Van Assche N, Quirynen M. Tolerance within a surgical guide. Clin. Oral Impl. Res. 21, 2010; 455–458. doi: 10.1111/j.1600‐0501.2009.01836.x
Microbial leakage through the implant–abutment interface of morse taper implants in vitro
Authors: Aloise João Pedro , Curcio Ricardo , Laporta Marcia Zorello , Rossi Liliane , Da Silva Adriana Madeira Álvares , Rapoport Abrão
Published: January 2010

Objectives: The aim of this study was to determine and compare the frequency of bacterial leakage of Streptococcus sanguinis biotype II along the implant–abutment interface between two systems of morse taper dental implants. Different methods of activation of the taper abutments were used: tapped‐in (Bicon©) and screwed‐in (Ankylos®).

Materials and methods: Twenty sterile assemblies were used and attached, 10 Bicon© and 10 Ankylos® implants, according to manufacturers' specifications. They were then totally immersed within 20 test tubes containing a sterile nutrient solution brain–heart infusion (BHI). The internal part of the 20 implants was previously inoculated with 0.1 μl of S. sanguinis II (ATCC 10557) and then connected to the respective abutments. The assemblies were incubated under anaerobic conditions for 14 days in an autoclave at 37°C. They were monitored daily for solution cloudiness resultant from microbial leakage on the interface of the assemblies. For statistical analysis, the Fisher test was applied and significance was assigned at the 5% level.

Results: There was solution cloudiness, indicating the finding of bacterial growth inside two Bicon© assemblies and two Ankylos® assemblies 48 h after incubation. Microbial leakage was further substantiated by testing the suspension for the presence of Streptococcus sp. None of the sterility controls were contaminated. The frequency of bacterial leakage along the implant–abutment interface, with the two different morse taper implant systems, was 20% of the assemblies of each system. There were no statistical differences between them.

Conclusion: Irrespective of which of the two morse taper implant connection systems of activation was analyzed, tapped‐in (Bicon©) or screwed‐in (Ankylos®), this in vitro experiment showed bacterial leakage along the implant–abutment interface.

To cite this article:
 Aloise JP, Curcio R, Laporta MZ, Rossi L, da Silva AMÁ, Rapoport A. Microbial leakage through the implant–abutment interface of morse taper implants in vitro. Clin. Oral Impl. Res. 21, 2010; 328–335. doi: 10.1111/j.1600‐0501.2009.01837.x
RETRACTED: Histological and histomorphometric evaluation of immediate implant placement on a dog model with a new implant surface treatment
Authors: Calvo‐Guirado J. L. , Ortiz‐Ruiz A. J. , Negri B. , López‐Marí L. , Rodriguez‐Barba C. , Schlottig F.
Published: January 2010

Purpose: The aim of this study was to evaluate crestal bone resorption and bone apposition resulting from immediate post‐extraction implants in the canine mandible, comparing a conditioned sandblasted acid‐etched implant surface with a non‐conditioned standard sandblasted implant surface.

Material and methods: In this experimental study, third and fourth premolars and distal roots of first molars were extracted bilaterally from six Beagle dog mandibles. Each side of the mandible received three assigned dental implants, with the conditioned surface (CS) on the right side and the non‐conditioned surface (NCS) on the left. The dogs were sacrificed at 2 (n=2), 4 (n=2) and 12 weeks (n=2) after implant placement.

Results: The microscopic healing patterns at 2, 4 and 12 weeks for both implant types (CS and NCS) yielded similar qualitative bone findings. The mean crestal bone resorption was found to be greater for all implants with NCS (2.28±1.9 mm) than CS (1.21±1.05 mm) at 12 weeks. The mean percentage of newly formed bone in contact with implants was greater in implants CS (44.67±0.19%) than with the NCS (36,6±0.11%). There was less bone resorption with the CS than the NCS.

Conclusion: The data show significantly more bone apposition (8% more) and less crestal bone resorption (1.07 mm) with the CS than with the NCS after 12 weeks of healing. This CS can reduce the healing period and increase bone apposition in immediate implant placements.

To cite this article:
 Calvo‐Guirado JL, Ortiz‐Ruiz AJ, Negri B, López‐Marí L, Rodriguez‐Barba C, Schlottig F. Histological and histomorphometric evaluation of immediate implant placement on a dog model with a new implant surface treatment. Clin. Oral Impl. Res. 21, 2010; 308–315. doi: 10.1111/j.1600‐0501.2009.01841.x
Healing of rabbit calvarial bone defects using biphasic calcium phosphate ceramics made of submicron‐sized grains with a hierarchical pore structure
Authors: Park Jin‐Woo , Kim Eun‐Suk , Jang Je‐Hee , Suh Jo‐Young , Park Kwang‐Bum , Hanawa Takao
Published: January 2010

Objectives: This study investigated the efficacy of new bone graft substitutes – biphasic calcium phosphates (BCP) made of submicron‐sized grains with fully interconnected wide‐range micron‐scale pores in two different macrodesigns: donut shaped with a 300–400 μm central macropore (n‐BCP‐1) or rod‐shaped (n‐BCP‐2) – in the healing of rabbit calvarial defects, and compared their bone‐healing properties with those of various commercial bone substitutes, which included substitutes with similar BCP composition (MBCP and Osteon), anorganic bovine bone (Bio‐Oss), and β‐TCP (Cerasorb).

Material and methods: The surface morphology of the bone substitutes was investigated using scanning electron microscopy (SEM). Defects 8 mm in diameter were created in the calvaria of 30 adult male New Zealand White rabbits and were filled with six types of bone substitutes. The percentage of newly formed bone (NB%) was evaluated histomorphometrically 4 and 8 weeks after implantation.

Results: SEM observation showed submicron‐sized grains with fully interconnected micropore structures in the n‐BCP‐1 and n‐BCP‐2 groups; these groups also showed considerable new bone formation in inner micropores as well as on the outer surfaces. The n‐BCP‐1 group exhibited enhanced new bone formation and direct ingrowth of bone tissue with blood vessels into central pores. Histomorphometric analysis showed significantly greater NB% in the n‐BCP‐1 group when compared with the other groups at 4 and 8 weeks (P<0.05).

Conclusion: A new BCP ceramics made of submicron‐sized grains with a hierarchical pore structure was an effective osteoconductive material for the treatment of osseous defects of rabbit calvaria.

To cite this article:
 Park J‐W, Kim E‐S, Jang J‐H, Suh J‐Y, Park K‐B, Hanawa T. Healing of rabbit calvarial bone defects using biphasic calcium phosphate ceramics made of submicron‐sized grains with a hierarchical pore structure. Clin. Oral Impl. Res. 21, 2010; 268–276. doi: 10.1111/j.1600‐0501.2009.01846.x
Oral health care needs and oral health‐related quality of life (OHIP‐14) in homeless people
Authors: Daly Blánaid , Newton Tim , Batchelor Paul , Jones Kate
Published: January 2010

Daly B, Newton T, Batchelor P, Jones K. Oral health care needs and oral health‐related quality of life (OHIP‐14) in homeless people. Community Dent Oral Epidemiol 2010. © 2009 John Wiley & Sons A/S

Abstract –  Objectives:  The aim of this study was (i) to determine the oral health status and oral health care needs of this population, (ii) to assess oral health‐related quality of life using OHIP‐14 and (iii) to explore whether there is a relationship between oral health status and oral health‐related quality of life.

Methods:  A convenience sample was drawn from eight facilities catering for homeless people in south east London. Participants were invited to attend an outreach dental clinic and receive a clinical oral health and treatment needs assessment. The impact of oral disease was assessed using OHIP‐14.

Results:  There were 102 people from a range of vulnerable housing situations invited to participate in the study. The mean age was 39.5 (SD ± 12.3) and 92% (n = 92) were men. The mean DMFT of dentate participants (n = 94) was 15.5 (SD ± 7.6), mean DT was 4.2 (SD ± 5.2), mean MT was 6.8 (SD ± 6.0) and mean FT was 4.6 (SD ± 4.8). Normative needs were extensive with 76% having a restorative need, 80% having a need for oral hygiene measures and periodontal treatment and 38% having a prosthetic treatment need. Ninety one per cent of homeless people experienced at least one impact and the mean number of impacts (n = 90) was 5.9 (SD ± 4.8).The most commonly experienced oral health‐related quality of life impacts were in the dimension of pain, with aching in the mouth having a prevalence of 65% and discomfort while eating foods having a prevalence of 62%. Forty‐four per cent felt handicapped by their oral condition. The experience of oral impact had only a slight relationship with clinical status and there were no differences in clinical status or oral impact by vulnerability of housing situation.

Conclusions:  Oral health care needs were extensive and greater than that of the general population in the UK, although disease levels were similar. While homeless people experienced many more oral impacts (as measured with OHIP‐14) compared with adults of the same age in the general population in the UK, there was only a slight relationship with clinical status and oral health‐related quality of life.
Social gradients and cumulative effects of income and education on dental health in the Fourth German Oral Health Study
Authors: Geyer Siegfried , Schneller Thomas , Micheelis Wolfgang
Published: January 2010

Geyer S, Schneller T, Micheelis W. Social gradients and cumulative effects of income and education on dental health in the Fourth German Oral Health Study. Community Dent Oral Epidemiol 2010. © 2009 John Wiley & Sons A/S

Abstract – Objective: To consider differential effects of income and education on oral health for each indicator separately and in combination. Finally the combined effects of the lowest income level and the lowest level of education were examined.

Methods: Data were drawn from the Fourth German Oral Health Study. They were collected using proportional random sampling in order to obtain information also for less densely populated regions. The subjects included in the study were between 35 and 44 years of age (n = 925). It included a clinical dental examination and a sociological survey. Social differentiation was depicted by education and income (divided into categories), oral health was measured using the DMFT‐index.

Results: Social gradients emerged for both indicators of social differentiation. The effects derived from single analyses were somewhat higher than those obtained by simultaneous estimations. The odds ratio of the lowest as compared with the highest income category was OR = 3.74 and OR = 2.34 in the analysis with both indicators. For education the respective effects were OR = 3.75 and OR = 2.95. The cumulative effect of the lowest income and the lowest educational level combined was OR = 6.06.

Conclusion: Education and income are shaping social inequalities in oral health independently from each other, and they are only moderately correlated. They refer to different dimensions of disadvantage thus making preventive measures more complicated.
Differential item functioning in a Brazilian–Portuguese version of the Child Perceptions Questionnaire (CPQ11‐14)
Authors: Traebert Jefferson , Lacerda Josimari Telino de , Thomson W. Murray , Page Lindie Foster , Locker David
Published: January 2010

Traebert J, de Lacerda JT, Thomson WM, Foster Page L, Locker D. Differential item functioning in a Brazilian–Portuguese version of the Child Perceptions Questionnaire (CPQ11‐14). Community Dent Oral Epidemiol 2010. © 2010 John Wiley & Sons A/S.

Abstract –  Objective:  To determine whether a Portuguese language version of the Child Perceptions Questionnaire for 11–14‐year‐olds (CPQ11‐14) showed differential item functioning (DIF) when compared with the original English language version.

Methods:  CPQ11‐14 data from a school‐based Brazilian study (n = 138) was compared with CPQ11‐14 data collected as part of a school‐based study conducted in New Zealand (n = 322). In order to detect DIF, ordinal logistic regression analysis was performed with each CPQ11‐14 item as the dependent variable. The independent variables were language group (English versus Portuguese), the CPQ11‐14 sub‐scale score of which the item was a part, and an interaction term for language*sub‐scale score. Nonuniform DIF was deemed to be present if the interaction term was significant. Moderate to large uniform DIF was deemed to be present if after removing the interaction term the β coefficient (log odds ratio) for language group was significant and numerically greater than 0.64. Analyses were also undertaken to detect pseudo‐DIF.

Results:  Nonuniform DIF was found in five items and moderate to large uniform DIF in an additional four items. Analyses using ‘purified’ sub‐scale scores indicated that little of the DIF detected was pseudo‐DIF. A comparison of the language groups using DIF affected and DIF‐free overall and subscale CPQ11‐14 scores revealed that the DIF detected had only a marginal effect on the differences between language groups in scores.

Conclusion:  Oral health‐related quality of life questionnaires, particularly those that have been translated, need to be assessed for DIF and its likely impact on group comparisons.
Yeats’s “Sailing to Byzantium”. The “Esoteric” Four‐Stanza Structure
Authors: Genung Michael
Published: January 2010

The celebrated W. B. Yeats was a superb verbal technician who evolved from writing lyrical verse in his youth to a sparser, more “metaphysical” style of poetry in his later years. Quite often, these mature poems can be seen as visionary expressions of a life spent as unorthodox spiritual adventurer – Yeats was for twenty‐one years an avid member of the Golden Dawn, a group whose practice of ritual magic centered on their own occult, rather eccentrically eclectic interpretation of the Kabbala. The poet himself readily attested to the profound influence his association with that order had on his own thinking. Nevertheless, the impact of this esoteric background has not often been expounded in detail within critical analyses of his work. In partial rectification, this paper will undertake an analysis of one of his most enigmatic poems, “Sailing to Byzantium,” utilizing key doctrines drawn from the Hermetic Kabbala, doctrines that themselves depend largely on a Neoplatonic substratum. The ensuing interpretation will strive to demonstrate that the four stanzas of the poem conform to a fourfold metaphysical‐ontological division that occurs within both the Hermetic Kabbala and Classical Neoplatonism, a division that tends to construe states of being as differing modes of consciousness.
Antimicrobial and conformational studies of the active and inactive analogues of the protegrin‐1 peptide
Authors: Rodziewicz‐Motowidło Sylwia , Mickiewicz Beata , Greber Katarzyna , Sikorska Emilia , Szultka Łukasz , Kamysz Elżbieta , Kamysz Wojciech
Published: January 2010

The natural antimicrobial cationic peptide protegrin‐1 displays a broad spectrum of antimicrobial activity and rapidly kills pathogens by interacting with their cell membrane. We investigated the structure–activity relationships of three protegrin‐1 analogues: IB‐367 (RGGLCYCRGRFCVCVGR‐NH2), BM‐1 (RGLCYCRGRFCVCVG‐NH2) and BM‐2 (RGLCYRPRFVCVG‐NH2). Our antimicrobial and antifungal activity studies of these peptides showed that BM‐1 was much more active than IB‐367 against Gram‐positive bacteria and fungi, whereas BM‐2 was inactive. The BM‐1 peptide showed fourfold reduced haemolysis relative to IB‐367, an additional advantage of this peptide. In addition, BM‐1 was about 15% cheaper than IB‐367 to synthesize. The absence of two cysteine residues in the BM‐2 sequence could be the main reason for its unstable conformation and antimicrobial inactivity. The solution structures of these peptides were determined in dimethyl sulphoxide using two‐dimensional NMR and restrained molecular dynamics calculations. IB‐367 and BM‐1 formed short, antiparallel, β‐hairpin structures connected by a type II′β‐turn. The shorter, inactive BM‐2 analogue exhibited major and minor conformations (predominantly unordered) in the NMR spectra and was much more flexible.
Investigational New Drug‐Directed Toxicology and Pharmacokinetic Study of 4‐[3‐(2‐Nitro‐1‐Imidazolyl)‐Propylamino]‐7‐Chloroquinoline Hydrochloride (NLCQ‐1, NSC 709257) in Beagle Dogs
Authors: Papadopoulou Maria V. , Bloomer William D. , Torti Vincent R. , Page John G.
Published: January 2010

Abstract:  4‐[3‐(2‐Nitro‐1‐imidazolyl)‐propylamino]‐7‐chloroquinoline hydrochloride (NLCQ‐1), a 2‐nitroimidazole‐based hypoxia‐selective cytotoxin has been shown to target hypoxic regions of solid tumours. The present study is one of several pre‐clinical toxicology studies conducted in support of an ‘investigational new drug’ (IND) application to test this agent as an adjuvant to radio/chemotherapy for the treatment of cancer in humans. Twenty‐four dogs were each assigned to one vehicle control group or to one of three test article‐treated groups (three dogs/sex/treatment group). Intravenous (i.v.) doses of 0, 2.74, 5.48 and 10.95 mg/kg/day (54.8, 109.6 or 219 mg/m2/day) were administered on a per day × 5 days (qd × 5) schedule. NLCQ‐1 was formulated as a solution in sterile saline at 1.5 mg/ml. None of the dogs died during this 33‐day study. With few exceptions, most of the clinical signs of toxicity were noted within 2 hr following dosing in the 10.95 mg/kg/day dose group. These observations included aggressive behaviour, ataxia, tachypnea, emesis, hypoactivity, excessive salivation, tremors, and involuntary urination and defecation. Aggressive behaviour was judged to be dose‐limiting. No clinical signs of toxicity were noted during the 28‐day observation period that followed the 5‐day dose period. Findings in a functional observation battery examination were consistent with the clinical observations. No drug‐related effects were noted on the body weight or food consumption values, and no drug‐related changes were noted during ocular examinations made on these animals prior to scheduled necropsy or during examination of electrocardiogram recordings made at 15 min. and 2 hr after dosing on days 1 and 5. No definitive changes in haematology, clinical chemistry or coagulation values were noted in dogs treated with NLCQ‐1. NLCQ‐1 was detected in the plasma of treated dogs on days 1 and 5, up to 60 min. after dosing (2.74 and 5.48 mg/kg/day) and up to 8 hr after dosing (10.95 mg/kg/day). There was a dose‐related increase in maximum plasma concentration of NLCQ‐1 at 5 min. after dosing; comparable concentrations were noted on days 1 and 5. No definitive test article‐related lesions were noted during microscopic evaluation of tissues from dogs in this study, although lesions noted at the injection site and in the vascular tissue, lungs, thymus, prostate gland, muscle, adrenal cortex and tongue may have resulted from treatment with this drug. Any drug‐related toxicity noted was readily reversible and not cumulative. No sex difference was detected in the susceptibility to NLCQ‐1‐induced toxicity.
Original Research—Ejaculatory Disorders: The Role of Short Frenulum and the Effects of Frenulectomy on Premature Ejaculation
Authors: Gallo Luigi , Perdonà Sisto , Gallo Antonio
Published: January 2010

Introduction

The role of short frenulum and the effects of frenulectomy on premature ejaculation (PE) were never investigated.

Aims

The aims of this study were to evaluate the prevalence of short frenulum in a population of patients affected by lifelong PE and to investigate the role of frenulectomy as first-line treatment for this condition.

Methods

We performed frenulectomy to patients complaining of lifelong PE in which we found the presence of a short frenulum at physical examination. We evaluated intravaginal ejaculatory latency time (IELT) and the score of a validated PE questionnaire at baseline and after frenulectomy.

Main Outcome Measures

We evaluated the change in mean IELT and in mean PE questionnaire score.

Results

We found the presence of a short frenulum in 59 out of 137 (43%) subjects who came to our center complaining of lifelong PE. Mean age of study population was 38.2 years (±5.3 standard deviation). At baseline period, mean IELT was 1.65 minutes (±1.15), and mean PE questionnaire score was 15.8 (±2.85). No complications related to surgery occurred. Mean follow-up time was 7.3 months (±3.18). After frenulectomy, mean IELT was 4.11 minutes (±1.77), and mean PE questionnaire score was 9.85 (±3.2). An increase in mean IELT of 2.46 minutes (P <0.0001) and a reduction in mean PE questionnaire symptoms score of 5.95 (P <0.0001) were noted.

Conclusion

Short frenulum is a genital anomaly found in 43% of individuals affected by lifelong PE in our data set. We suggest always ruling out at physical examination the presence of a short frenulum in all patients complaining of PE and to propose frenulectomy as first-line treatment in these cases.
The Impairment of Sexual Function Is Less Distressing for Menopausal than for Premenopausal Women
Authors: Berra Marta , De Musso Francesca , Matteucci Carlotta , Martelli Valentina , Perrone Anna Myriam , Pelusi Carla , Pelusi Giuseppe , Meriggiola Maria Cristina
Published: January 2010

Introduction

Menopause requires psychological and physical adjustments because of the occurring significant hormonal changes. Sexuality is one of the aspects that undergoes the most profound modifications. Preliminary data suggest that sometimes women do not regard sexual changes as problematic and often readjust their life and relationship according to their new physical status.

Aim

The aim of our study was to evaluate sexual function and the way women feel by comparing healthy postmenopausal and premenopausal women.

Methods

One hundred menopausal (M) and 100 premenopausal (pM) healthy women were asked to complete anonymous questionnaires to assess sexual function and stress related to sexual activity.

Main Outcome Measures

Female Sexual Function Index (FSFI), Female Sexual Distress Scale (FSDS) were completed by M and pM women.

Results

Medium FSFI score was 20.5 ± 9.6 and 26.4 ± 7.7 (P <0.0005) and medium FSDS score was 12.1 ± 11.7 (95% CI 9.7–14.4) and 11.3 ± 10.2 (P = 0.917) for M and pM women, respectively. Twenty-five of the 69 M women and 20 of the 31 pM women with a pathological score in the FSFI questionnaire scored higher than 15 in the FSDS (P <0.0005). The overall prevalence of sexual dysfunction was 20% and 25% (P = 0.5) in the M and pM women.

Conclusions

Our data confirm that menopause is associated with changes in sexual function that may be compatible with sexual dysfunction. However, personal distress caused by these changes in sexual life appears to be lower among menopausal women (36.2%) as compared with premenopausal women (64.5%). These data suggest that medical treatment for sexual health in menopause must be highly personalized and carefully prescribed.