bluuebunny/crossref_metadata_2025 huggingface dataset:
Dependence of the Sn0/2+ charge state on the Fermi level in semi-insulating CdTe
Authors: Babentsov V. , Franc J. , Elhadidy H. , Fauler A. , Fiederle M. , James R.B.
Published: October 2007

We explored the growth and characteristics of CdTe doped with Sn to heighten our understanding of the role of deep levels on electrical compensation and trapping. We demonstrated, for the first time, the strong dependence of the SnCd charge state on the Fermi-level variation (2–3kT) in high-resistivity CdTe. The concentration of deep traps for electrons was determined by the number of doubly positively charged Sn2+ atoms. Thermoelectric-effect spectroscopy and photovoltage measurements revealed the conversion of the SnCd defect from the electron SnCd2+ trap to the hole SnCd0 trap. The results agree well with the existence of a negative U-center in the SnCd0/2+ defect. We also showed that the neutral Sn defect is responsible for the near midgap C-band → bound hole radiative transitions band with a maximum at 0.76 eV.
Supramolecular structures formed by the self assembly of ionic fullerenes in binary liquid mixtures
Authors: Shiga Tohru , Motohiro Tomoyoshi
Published: October 2007

The self assembly of C60-N, N′-dimethylpyrrolidinium iodide (C60-DMePyI) in binary liquid mixtures has been investigated. C60-DMePyI self-organized into nanosheets in a mixture of toluene and iodomethane, and aggregated to form nanofibers in toluene. The dimensions of the nanosheets were several micrometers in length and about 100 nm in thickness. Scanning electron microscope observations indicated that a large number of nanorods having a diameter of about 20-nm formed matted nanosheets. When iodomethane alone was used as a solvent, supramolecular structures such as nanofibers and nanosheets were not produced. Structural analyses of the C60-DMePyI aggregates were carried out by laser Raman spectroscopy and x-ray diffraction (XRD). The Raman spectroscopic results suggested that an ordered chain of successive polyiodine units was formed in all the supramolecular aggregates. The XRD studies showed that the crystal systems of the nanosheets and nanofibers were monoclinic, though with different unit cells.
Tailoring deformation-induced effects in Co powders by milling them with α–Al2O3
Authors: Menéndez E. , Sort J. , Suriñach S. , Baró M.D. , Nogués J.
Published: October 2007

The evolution of the structural and magnetic properties of metal-ceramic, cermet, nanocomposite powders, consisting of Co and α–Al2O3in different proportions, prepared by ball milling has been investigated. The overall microstructure of the system, after long-term milling, is found to be very sensitive to the amount of α–Al2O3, yielding a less refined and faulted hexagonal-close-packed (hcp)-Co structure for the sample with larger α–Al2O3percentage. The increased presence of the ceramic counterpart also causes a delay of the face-centered-cubic (fcc) to hcp-Co stress-induced transformation during ball milling. The results seem to indicate an evolution of the role of α–Al2O3, from increasing locally the strain rate of the mechanical work for small amounts of ceramic to absorbing milling energy for large amounts of α–Al2O3. The magnetic properties correlate with the obtained microstructure, where the amount of hcp-Co and stacking faults and the isolation of the Co particles by the α–Al2O3control the coercivity.
Layered stacking characteristics of ternary zirconium aluminum carbides
Authors: Lin Z.J. , He L.F. , Li M.S. , Wang J.Y. , Zhou Y.C.
Published: October 2007

Layered stacking characteristics of ternary Zr–Al–C carbides were investigated using scanning transmission electron microscopy (STEM). Three previously unknown compounds, i.e., Zr4Al3C6, Zr5Al6C9, and Zr7Al6C11 were identified. The present study extends the structural information of ternary Zr–Al–C ceramics. The influence of the thickness of the NaCl-type Zr-C slab on the elastic properties of ternary Zr–Al–C ceramics is discussed based on first-principles calculations. In addition, direct atomic-resolution observations illustrate the process for forming the unique layered crystal structures of ternary Zr–Al–C ceramics. These results also provide insights into the formation mechanism of layered ternary Zr–Al–C carbides.
Plasticity of a TiCu-based bulk metallic glass: Effect of cooling rate
Authors: Shen J. , Huang Y.J. , Sun J.F.
Published: October 2007

Compressive deformation was experimentally investigated for Ti41.5Cu42.5Zr2.5Hf5Ni7.5Si1 bulk metallic glass (BMG) fabricated at different cooling rates. It was found that the ductility of the BMG alloy increased with increasing of the cooling rate in solidification. The alloy with a monolithic amorphous structure exhibited a large ductility, up to 12%. The effect of cooling rate on the ductility of the BMG alloy is interpreted in terms of the variation in amorphous nature and free volume of the as-cast materials.
Growth and characterization of TiN/SiN(001) superlattice films
Authors: Söderberg Hans , Odén Magnus , Flink Axel , Birch Jens , Persson Per O.Å. , Beckers Manfred , Hultman Lars
Published: October 2007

We report the layer structure and composition in recently discovered TiN/SiN(001) superlattices deposited by dual-reactive magnetron sputtering on MgO(001) substrates. High-resolution transmission electron microscopy combined withZ-contrast scanning transmission electron microscopy, x-ray reflection, diffraction, and reciprocal-space mapping shows the formation of high-quality superlattices with coherently strained cubic TiN and SiN layers for SiN thickness below 7–10 Å. For increasing SiN layer thicknesses, a transformation from epitaxial to amorphous SiNx(x⩾ 1) occurs during growth. Elastic recoil detection analysis revealed an increase in nitrogen and argon content in SiNxlayers during the phase transformation. The oxygen, carbon, and hydrogen contents in the multilayers were around the detection limit (∼0.1 at.%) with no indication of segregation to the layer interfaces. Nanoindentation experiments confirmed superlattice hardening in the films. The highest hardness of 40.4 ± 0.8 GPa was obtained for 20-Å TiN with 5-Å-thick SiN(001) interlayers, compared to monolithic TiN at 20.2 ± 0.9 GPa.
Electromigration induced microstructure and morphological changes in eutectic SnPb solder joints
Authors: Lee A. , Ho C.E. , Subramanian K.N.
Published: October 2007

Simultaneous direct current stressing with thermal aging accelerates the migration of conducting species resulting in significant microstructural coarsening. Because of the synergistic fields influence, such coarsening begins from the anode and propagates toward the cathode. Prolonged current stressing with 104 A/cm2 at 150 °C causes the inter-lamellar eutectic SnPb to become a two-layer structure, with a Pb-rich layer adjacent to the anode and an Sn-rich layer adjacent to the cathode. This mass movement causes hillock/valley formation, and the extents of such surface undulations increase with increases in the time duration of current stressing as well as with the joint thickness. In thinner solder joints these events occur sooner, although the extents of surface undulations depend on the thickness of joints. In addition, Cu present in the substrate and in the intermetallic layer at the cathode migrates to form Cu6Sn5 within the Sn-rich layer, in a region close to the Pb-rich layer.
Effect of oxygen inclusion on microstructure and thermal stability of copper nitride thin films
Authors: Du Y. , Huang R. , Song R. , Ma L.B. , Liu C. , Li C.R. , Cao Z.X.
Published: October 2007

Copper oxynitride thin films with a minor oxygen content were prepared on silicon wafers at 100 °C by reactive magnetron sputtering using a gas mixture of nitrogen and oxygen. Addition of oxygen immediately improves the compactness of the deposits, which otherwise comprise ragged Cu3N nanocrystallites. With an oxygen content <10.0 at.%, the deposits reveal some sporadic Cu2O nanocrystals under transmission electron microscopy, but their x-ray diffraction (XRD) patterns exhibit reflections only from the Cu3N phase. The decomposition temperature, at which the sample after prolonged annealing shows Cu reflections on its XRD pattern, can be raised from 300 °C for stoichiometric Cu3N to 360 °C. The decomposition product after annealing at 450 °C is pure copper having an electrical resistivity of 8.94 × 10−8 Ω·m at room temperature, which can be taken as a good conductor and stands in strong contrast with the oxynitride matrix with an electrical resistivity of 6.87 × 10−2 Ω·m. These results constitute progress in the search of directly writable copper nitride-based materials.
Radical Change and Wikis: Teaching New Literacies
Authors: Luce‐Kapler Rebecca
Published: October 2007

By using Radical Change texts and wikis—online, open‐source, Web‐creation software—the researcher in this study anticipated that students would create “e‐literature” that would have interesting hyperlinks, both with other students' texts and throughout the story. Instead, the students did very little connecting, wrote small fragments of text, and relied primarily on images to “tell” a story.

Nevertheless, during the interviews, the researcher found that the students had developed some visual literacy skills, and she identified four teaching practices that were important for engaging students in literacy processes:

focusing events

interacting in groups

enabling constraints

playing opportunities
Effective Content Vocabulary Instruction in the Middle: Matching Students, Purposes, Words, and Strategies
Authors: Flanigan Kevin , Greenwood Scott C.
Published: October 2007

Despite what we have learned about effective vocabulary instruction, and despite the fact that many teachers know vocabulary is important, teachers do not always incorporate best practices with their own instruction. These authors argue that part of the reason may be that the general instructional recommendations of vocabulary research don't always help teachers, particularly content teachers, bridge theory and practice. The issues in teaching vocabulary are often specific to the content, the students, and the instructional purposes. To help teachers address questions of which words to teach, which strategies to use, and how long to spend on teaching them, the authors propose a “four‐level” instructional framework tailored to content area vocabulary. Using this framework, the authors show content teachers how to choose words and methods that match their students and their purposes.
Secondary Literacy Coaching: A Macedonian Perspective
Authors: Sturtevant Elizabeth G. , Linek Wayne M.
Published: October 2007

Vocational high schools in the Republic of Macedonia are making efforts to add content literacy and learning strategies to their curricula through Secondary Education Activity (SEA). SEA is a collaboration of the government of Macedonia, the International Reading Association, the American Institutes for Research, and the United States Agency for International Development to provide schools with updated curricula and to enable teachers to move from lecture‐style instruction to instruction that included active learning and links between the school, community, and workplace. As part of this project, educators participated in workshops led by international volunteers and 16 Macedonian classroom teachers selected to become literacy coaches. The trained educators have subsequently led training at their own schools. This article focuses on the perceptions of the 16 new literacy coaches about their own professional development and dilemmas they have had to overcome.
Examining Ways Readers Engage With Websites During Think‐Aloud Sessions
Authors: Damico James , Baildon Mark
Published: October 2007

Findings from this study of how two pairs of eighth‐grade students each transacted with a website during think‐aloud sessions at the conclusion of a curricular unit on Mexico and migration highlight the ways the students engaged in three interrelated tasks:

Identifying and making sense of “new” information

Evaluating claims and evidence

Considering ways to use the site in the writing of their own narrative

While these findings represent ways that these students demonstrated proficiency with literacy practices in beginning to read websites in more disciplined and disciplinary ways, they also point to two key challenges: contextualizing and corroborating sources of information and setting purposes for reading websites in a dynamic learning context.
The Spectacle and Detournement
Authors: Trier James
Published: October 2007

This Media Literacy column is a follow‐up to the column in the September 2007 issue that discussed Guy Debord and the artistic, political avant‐garde organization called the Situationist International. This column continues the discussion of the situationist concepts of the spectacle and detournement by explaining quick and easy ways to introduce these sophisticated concepts to middle school or high school students by showing selected YouTube.com videos.
Strategy Instruction During Word Study and Interactive Writing Activities
Authors: Williams Cheri , Lundstrom Ruth P.
Published: October 2007

In this project, a teacher researcher and a university researcher used qualitative data collection and analysis procedures to collaboratively investigate the efficacy of interactive writing as a context for guided practice in the use of specific spelling strategies that had been taught during daily word study lessons. The researchers also examined first‐grade, Title I children's use of those strategies during independent writing events.

Findings of the project indicated that the teacher researcher taught a number of fundamental spelling strategies during word study instruction, which were categorized as Tools of the Trade and Tools of the Mind. Results also demonstrated the ways in which interactive writing provided meaningful opportunities for the teacher to scaffold the children's use of the strategies that were taught. Finally, the project suggested that students appropriated a number of those strategies and used them independently during writing activities in the regular classroom. The project supports the use of both word study and interactive writing instruction in the early literacy program.
Offering or Limiting Opportunities: Teachers' Roles and Approaches to English‐Language Learners' Participation in Literacy Activities
Authors: Yoon Bogum
Published: October 2007

After examining the teachers of sixth‐grade English‐language learners (ELLs) in their regular classrooms, the authors of this study found that the ELLs' active or passive participation was much influenced by the teachers' approach to the students but not by the teachers' use of specific methods only. While the teachers' focus on American monoculturalism provided little room for the ELLs' participation in the cultural discourse, the teachers' approach based on the students' cultural and social needs promoted the students' participation. The study aims to help reading teachers be aware of their roles and teaching practices as supports or constraints on ELLs' active participation in the mainstream classroom.
Insights From Teachers Who Analyzed Transcripts of Their Own Classroom Discussions
Authors: Kucan Linda
Published: October 2007

Transcript analysis is a way for teachers to engage in inquiry on their own practice. The insights of three teachers who engaged in transcript analysis of their own classroom discussions are described in this article.

The teachers analyzed and reflected on their transcripts using a coding manual and a comparison and reflection guide. The coding manual provided labels for coding the kinds of questions and teacher responses that occurred during the teachers' text‐based discussions. The comparison and reflection guide guided the teachers in organizing their data and invited them to reflect on text selection, decisions about where to stop in the text to pose a question, kinds of questions that supported student effort in developing an understanding of text ideas, and kinds of responses to students that extended students' thinking.
Technology and Current Reading/Literacy Assessment Strategies
Authors: Balajthy Ernest
Published: October 2007

Computer‐based technologies offer promise as a means to assess students and provide teachers with better understandings of their students' achievement. This article describes recent developments in computer‐based and web‐based reading and literacy assessment, focusing on assessment administration, information management, and report creation. In addition, current software for observational record keeping, portfolio systems, and recreational reading management is considered. Finally, several web‐based sources are described that provide teachers with tools for improving assessment.
Overlapping Vocabulary and Comprehension: Context Clues Complement Semantic Gradients
Authors: Greenwood Scott C. , Flanigan Kevin
Published: October 2007

Despite the clear and longstanding connection between meaning vocabulary and reading comprehension, programs designed to teach vocabulary have often had surprisingly little impact on overall reading ability. One possible reason for this small effect is that teaching methods may not make this vocabulary‐to‐comprehension connection explicit for the students.

To address this disconnect, this article describes practical tips for overlapping vocabulary and comprehension instructional methods. Specifically, the authors combined two strategies, context clues and semantic gradients, to support their graduate students as they, in turn, helped their own students examine shades of meaning among related sets of words. The purpose of overlapping these two strategies is to enable students to reconnect individual word meanings back to the text, helping them bridge the vocabulary to comprehension divide. A specific sequence of instruction is provided.
Teacher‐Created Electronic Books: Integrating Technology to Support Readers With Disabilities
Authors: Rhodes Joan A. , Milby Tammy M.
Published: October 2007

The No Child Left Behind Act of 2001 holds U.S. schools accountable for the yearly assessment of all students as they progress toward meeting state educational goals. Students with disabilities continue to be a focal point for improving student achievement at the school and district levels. Creating teacher‐made electronic books is an effective method of using technology to support students with disabilities. In the elementary classroom, assistive technologies such as electronic books can capture student responses and enhance student retellings of engaging children's literature. This article provides a brief overview of the use of electronic books to improve students' retellings, and specific instructions for creating electronic books that support struggling readers.
Making It Happen: Sustaining a Commitment for Reading Success
Authors: Whitfield Vickie , Moore Jane
Published: October 2007

Some practical ideas for teachers and literacy coaches are put forth in this column. These suggestions can make any school a more collaborative environment.
A Child's Response to Intervention Requires a Responsive Teacher of Reading
Authors: Lose Mary K.
Published: October 2007

There are a number of principles that teachers of reading and administrators need to keep in mind to ensure that Response to Intervention (RTI) enables struggling literacy learners to achieve success within the provisions of the reauthorized Individuals with Disabilities Education Improvement Act (IDEA). The author argues for evidence‐based RTI approaches that emphasize teacher expertise and sustained teacher development, that are scalable, and that can be implemented immediately by education systems.
Effect of Periodontal Therapy on Pregnancy Outcome in Women Affected by Periodontitis
Authors: Tarannum Fouzia , Faizuddin Mohamed
Published: October 2007

Background: There is convincing evidence to suggest that infections affecting the mother during pregnancy may produce alterations in the normal cytokine‐ and hormone‐regulated gestation, which could result in preterm labor, premature rupture of membranes, and preterm birth (PTB). Studies in the late 1990s associated periodontitis with preterm low birth weight (PLBW) deliveries, and this may have similar pathogenic mechanisms as other maternal infections. This study determined the effect of non‐surgical periodontal therapy on pregnancy outcome.

Methods: A total of 200 pregnant women with periodontitis were randomly assigned to treatment and control groups. Detailed data about previous and current pregnancies were obtained. All women received a full‐mouth periodontal examination, including oral hygiene index‐simplified, bleeding index, and clinical attachment level. The women in the treatment group received non‐surgical periodontal therapy during the gestational period, and those in the control group received periodontal treatment after delivery. Periodontal therapy included plaque control instructions and scaling and root planing performed under local anesthesia. The outcome measures assessed were gestational age and birth weight of the infant. PTB was recorded when delivery occurred at <37 weeks of gestation, and low birth weight (LBW) was recorded when the infant weighed <2,500 g.

Results: There were 53 PTBs in the treatment group and 68 PTBs in the control group. Twenty‐six LBW infants were recorded in the treatment group, and 48 LBW infants were noted in the control group. The mean gestational ages were 33.8 ± 2.8 weeks and 32.7 ± 2.8 weeks in the treatment and control groups, respectively. The difference was statistically significant at P <0.006. The mean birth weight was 2,565.3 ± 331.2 g in the treatment group and 2,459.6 ± 380.7 g in the control group, with the difference being statistically significant at P <0.044. A multiple regression model showed a significant effect of periodontal treatment on birth outcomes.

Conclusions: Non‐surgical periodontal therapy can reduce the risk for preterm births in mothers who are affected by periodontitis. Additional multicentered, randomized, controlled clinical trials are required to confirm this link between periodontitis and PLBW.
Differential Expression of E‐Cadherin and Cytokeratin 19 and Net Proliferative Rate of Gingival Keratinocytes in Oral Epithelium in Periodontal Health and Disease
Authors: Nagarakanti S. , Ramya S. , Babu Praveen , Arun K.V. , Sudarsan Sabitha
Published: October 2007

Background: The effects of periodontal disease on the oral gingival epithelium (OGE) have not been documented fully because they may not be as dramatic as those seen on the junctional epithelium. The aim of this study was to estimate the changes occurring in the OGE with respect to its proliferation and E‐cadherin and cytokeratin 19 (K19) expression during pocket formation.

Methods: Gingival samples were collected from 17 periodontally healthy subjects and 18 subjects with chronic periodontitis. K19 and E‐cadherin levels were analyzed immunohistochemically. The net proliferative rate was calculated as the difference between the proliferative rate and the apoptotic rate as determined by immunohistochemical analysis of Ki‐67 and p53, respectively.

Results: There was a significant increase in the net proliferative rate of the OGE during pocket formation (periodontitis group, 220.90 ± 46.85; healthy group, 107.60 ± 25.86; P <0.001). There was a significant reduction in E‐cadherin expression (periodontitis group, 0.837 ± 0.428; healthy group, 1.846 ± 0.555) and a significant increase in K19 expression during pocket formation (periodontitis group, 1.45 ± 0.686; healthy group, 0.533 ± 0.410).

Conclusion: OGE appears to undergo significant changes in proliferation and differentiation during pocket formation that do not seem to be restricted to proteolytic destruction by the invading microorganisms.
The Effect of 0.12% Chlorhexidine Gluconate Rinsing on Previously Plaque‐Free and Plaque‐Covered Surfaces: A Randomized, Controlled Clinical Trial
Authors: Zanatta Fabrício B. , Antoniazzi Raquel P. , Rösing Cassiano K.
Published: October 2007

Background: Previous in vitro studies showed little bactericidal effect on structured oral biofilm after exposure to chlorhexidine (CHX). In vivo evidence of a CHX effect against structured biofilm is scarce. The purpose of this study was to compare the efficacy of 0.12% CHX gluconate on previously plaque‐free and plaque‐covered surfaces.

Methods: This study had a single‐masked, randomized split‐mouth, 21‐day experimental gingivitis design including 20 individuals who refrained from all mechanical plaque control methods for 25 days. On day 4 of plaque accumulation, the individuals had two randomized quadrants cleaned; the other two quadrants served as the plaque‐covered surfaces. Also, on day 4, the individuals started rinsing with 0.12% CHX gluconate for 21 days. The Quigley and Hein plaque index (PI), gingival index (GI), and gingival crevicular fluid (GCF) volume were assessed at baseline and days 21 and 25. The PI also was assessed at days 4, 11, and 18.

Results: Intergroup comparisons showed statistically higher PI throughout the study on the plaque‐covered surfaces compared to the plaque‐free surfaces. When the inflammatory response over time was analyzed, a statistically greater increase in GI (from 0.21 ± 0.02 to 0.93 ± 0.03 versus from 0.18 ± 0.01 to 0.52 ± 0.03 on plaque‐covered and plaque‐free surfaces, respectively) and GCF volumes (from 48.09 to 94.28 μl versus from 46.94 to 64.99 μl on plaque‐covered and plaque‐free surfaces, respectively) occurred on plaque‐covered surfaces after 21 days of plaque accumulation.

Conclusions: A 0.12% CHX gluconate mouthrinse had little antiplaque and antigingivitis effect on previously plaque‐covered surfaces. These results confirm the diminished effect of CHX on structured biofilm and reinforce the necessity of biofilm disruption before the initiation of CHX mouthrinse.
Periodontal Health and Adverse Pregnancy Outcome in 3,576 Turkish Women
Authors: Toygar H. Uslu , Seydaoglu G. , Kurklu S. , Guzeldemir E. , Arpak N.
Published: October 2007

Background: Preterm low birth weight (PLBW) is a problem encountered worldwide. The many causes of low birth weight (LBW) and premature or preterm birth (PTB) vary among developing/industrialized countries. Few studies have been published, in part because of the paucity of subjects and the ethnic heterogeneity of the populations. Our goals were to correlate maternal periodontal disease with birth outcomes in a Turkish population and evaluate maternal periodontal health.

Methods: This study consisted of 3,576 Turkish women who gave birth within 24 hours of the onset of labor. The adjusted odds ratio was generated from various logistic regression models.

Results: Codes from the Community Periodontal Index of Treatment Needs (CPITN) were evaluated according to treatment need (TN). The TN‐I rate was 24.2% (N = 866), the TN‐II rate was 73.5% (N = 2,628), and the TN‐III rate was 2.3% (N = 82). There were 566 (15.8%) adverse birth outcomes; the PTB with LBW rate was 4.2%; the PTB with normal birth weight (NBW) rate was 8.3%; the in term birth with LBW rate was 3.3%, and the in term birth with NBW rate was 84.2%. The overall PTB rate was 12.5% (N = 447), and the LBW rate was 7.5% (N = 269). The mean birth weight and weeks of gestation decreased as the CPITN level increased (P <0.001 for both). The LBW rate was 4.6% in the TN‐I group, 8.3% in the TN‐II group, and 14.6% in the TN‐III group. TPTB rates were 10.5%, 12.7%, and 26.8%, respectively, whereas adverse birth outcome rates were 12.0%, 16.6%, and 30.5%, respectively (P <0.01 for all). TN‐II and TN‐III were independent risk factors for LBW, PTB, and abnormal births in regression analyses.

Conclusion: Maternal periodontal disease may be a risk factor for an adverse pregnancy outcome.
Intravenous Bisphosphonate–Associated Osteonecrosis of the Jaw
Authors: Statz Thomas A. , Guthmiller Janet M. , Humbert Lewis A. , Johnson Georgia K.
Published: October 2007

Background: Bisphosphonates have received attention in the dental and medical scientific literature because of spontaneous necrosis of the jaw subsequent to their use. As the population ages, the use of these medications is increasing; the medical benefits seem to outweigh the risk for osteonecrosis of the jaw (ONJ).

Methods: A 71‐year‐old white male with a history of multiple myeloma, for which he was receiving intravenous (IV) zoledronic acid, presented for routine periodontal maintenance therapy. Intraoral observation revealed a 9 × 4‐mm area of exposed bone on the lingual aspect of tooth #31. Initially, the site was treated conservatively with topical 0.12% chlorhexidine gluconate application. Over a 12‐month period, the area of exposed bone increased in size to 20 × 9 mm and became symptomatic.

Results: The osseous necrosis progressed, ultimately resulting in a pathologic fracture of the right posterior mandible that was managed by reduction and stabilization. At 5 months post‐surgery, bone exposure persisted in the region, and a new site of osteonecrosis developed on the contralateral side of the jaw.

Conclusions: ONJ associated with IV bisphosphonate therapy is extremely difficult to manage. Dental treatment of ONJ should be conservative and provide relief to the patient. Patients with cancer who are candidates for IV bisphosphonate therapy should be informed of the potential risks and be referred for dental evaluation. Dentists should collaborate with physicians to minimize the risk for ONJ.
Enhanced Bone Regeneration in Beagle Dogs With Bovine Bone Mineral Coated With a Synthetic Oligopeptide
Authors: Park Jun‐Beom , Lee Jue‐Yeon , Park Yoon‐Jeong , Rhee Sang‐Hoon , Lee Sang‐Cheol , Kim Tae‐Il , Seol Yang‐Jo , Lee Yong‐Moo , Ku Young , Rhyu In‐Chul , Han Soo‐Boo , Chung Chong‐Pyoung
Published: October 2007

Background: Recombinant human bone morphogenic protein‐2 stimulates bone augmentation in animal models. The aim of this study was to evaluate the capacity of bovine bone mineral coated with synthetic oligopeptides to enhance guided bone regeneration in the beagle 3‐wall defect model and the clinical implications.

Methods: The second and fourth mandibular premolars of four adult beagle dogs were extracted bilaterally, and the extraction sites were allowed to heal for 2 months. An L‐shaped defect was prepared at the central part of the extraction site with a round bur on a low‐speed motor. Peptide‐coated bone mineral was implanted on one side, and uncoated bone mineral was implanted on the other side. The membrane was tucked underneath the mobilized lingual flap. New bone formation at the test and control sites was determined at 4 weeks.

Results: No specimen revealed any evidence of infection or foreign body reaction, and all wounds showed a good healing response. Sites augmented with peptide‐coated bone mineral and uncoated mineral exhibited excellent maintenance of the ridge contour. There was more new bone at sites with peptide‐coated bone mineral than at control sites. The new bone in sites with peptide‐coated bone mineral was deposited evenly around the graft material, and bone mineral was integrated fully into the new bone.

Conclusion: Deproteinized cancellous bovine bone coated with synthetic oligopeptides enhanced new bone formation, and it seemed to be a better material for guided bone regeneration in the beagle L‐shaped defect model.
SPARC Gene Polymorphism in Renal Transplant Patients With Gingival Overgrowth
Authors: Drozdzik A. , Kurzawski M. , Kozak M. , Banach J. , Drozdzik M.
Published: October 2007

Background: Gingival enlargement frequently occurs in transplant patients receiving immunosuppressive drugs. It was hypothesized that gingival enlargement associated with cyclosporin use results from increases in the number of fibroblasts and the volume of extracellular matrix. SPARC (secreted protein, acidic, and rich in cysteine) regulates cell–matrix interactions, binding to structural matrix proteins, and is induced by cyclosporin A (CsA). The aim of the study was to determine whether there is an association between SPARC genotypes and gingival enlargement in kidney transplant patients given CsA.

Methods: Sixty‐two unrelated kidney transplant patients with gingival overgrowth and 124 control transplant patients without overgrowth were enrolled into the study. Gingival overgrowth was assessed at 6 months after transplantation. All patients were given CsA as a principal immunosuppressive agent during the post‐transplant period. SPARC polymorphism was determined using polymerase chain reaction–restriction fragments length polymorphism assay.

Results: In kidney transplant patients with gingival overgrowth, the mean score of gingival overgrowth was 1.42 ± 0.63, whereas in control subjects it was 0. The distribution of SPARC 998C>G alleles among all kidney transplant patients, as well as in the two study subgroups, did not differ significantly from Hardy‐Weinberg equilibrium. The frequencies of the 998G allele (24.2% versus 18.5%) and of 998G allele carriers (40.3% versus 33.1%) among individuals with gingival overgrowth was higher compared to the control group, but the differences did not reach the statistical difference. The risk for gingival overgrowth was highest among patients carrying the 998GG genotype (OR 2.25), but it did not differ significantly from the risks associated with the other genotypes.

Conclusion: No association between SPARC gene polymorphism and gingival overgrowth was revealed in kidney transplant patients who were administered CsA.
Sarcoidosis Affecting the Periodontium: A Long‐Term Follow‐Up Case
Authors: Moretti Antonio J. , Fiocchi Maria F. , Flaitz Catherine M.
Published: October 2007

Background: Clinical manifestations of sarcoidosis affecting the periodontium could mimic aggressive periodontitis. This case report documents the occurrence of sarcoidosis affecting the periodontium, including its clinical features, diagnosis, treatment, and 6‐year follow‐up.

Methods: An individual with a history of pulmonary sarcoidosis was referred for evaluation and treatment of an aggressive periodontal condition. Clinical, radiographic, and histopathologic findings supported the diagnosis of sarcoidosis affecting the periodontium. Initial treatment consisted of reinforcement of oral hygiene, scaling and root planing, chlorhexidine rinses, and periodontal maintenance. The systemic disease was managed with prednisone, alendronate, and losartan. Twelve months later, the patient returned with severe attachment loss of sudden onset and gingival recession affecting the facial right surfaces of maxillary posterior teeth. In addition, he complained of chronic pain of moderate to severe intensity involving both jaws. The affected teeth were extracted and the surrounding alveolar bone was debrided. Intraoral sarcoidosis was confirmed by histologic findings, and his medications were changed to methotrexate and hydroxychloroquine.

Results: The patient has been followed for 6 years with continuation of the systemic medications and periodontal maintenance every 3 to 4 months without recurrence of intraoral sarcoidosis.

Conclusions: The main features of this unique periodontal presentation were pain, rapidly progressive gingival recession, and significant changes in alveolar bone density in focal areas. Careful review of medical history and close monitoring of intraoral conditions are critical for patients with a history of sarcoidosis. An intraoral biopsy is necessary to confirm a definitive diagnosis in cases with similar clinical findings.
Clinical Attachment Loss, Systemic Bone Density, and Subgingival Calculus in Postmenopausal Women
Authors: Brennan Renee M. , Genco Robert J. , Hovey Kathleen M. , Trevisan Maurizio , Wactawski‐Wende Jean
Published: October 2007

Background: Results of several studies investigating associations between systemic bone density and clinical attachment loss (CAL) of the soft tissue surrounding the teeth have varied. We investigated these associations in a relatively large study while evaluating potential confounding factors and effect modification by subgingival calculus and age.

Methods: In a cross‐sectional study of 1,329 postmenopausal women recruited from the Buffalo Women's Health Initiative Observational Study, systemic bone density was measured at the spine, hip, forearm, and whole body by dual‐energy x‐ray absorptiometry, and a complete oral health examination was conducted.

Results: We found the strongest associations between systemic bone density and CAL among women without subgingival calculus. Results were adjusted for age, cigarette smoking, education, and time since last dental cleaning. Presence or absence of subgingival calculus was a strong effect modifier. Among women without subgingival calculus, there were consistent inverse associations between systemic bone mineral density (BMD) and CAL (total forearm BMD β = −1.308; P = 0.001). Among women with subgingival calculus, there were no associations between systemic BMD and CAL (total forearm BMD β = −0.153; P = 0.677).

Conclusions: Our results provide evidence of an association between osteoporosis and one measure of periodontal disease severity, CAL. The associations between bone density, CAL, and subgingival calculus require further research, particularly in longitudinal studies.
Effects of Surface Hydrophilicity and Microtopography on Early Stages of Soft and Hard Tissue Integration at Non‐Submerged Titanium Implants: An Immunohistochemical Study in Dogs
Authors: Schwarz Frank , Ferrari Daniel , Herten Monika , Mihatovic Ilja , Wieland Marco , Sager Martin , Becker Jürgen
Published: October 2007

Background: The aim of the present study was to investigate the effects of surface hydrophilicity and microtopography on soft and hard tissue integration at non‐submerged titanium implants.

Methods: Implantation of conventional sand‐blasted large grit and acid‐etched (SLA) and chemically modified SLA (modSLA) titanium implants with differently structured transmucosal surfaces (SLA implants: machined [M‐SLA] or SLA [SLA‐SLA]; modSLA implants: mod acid‐etched [modA] [modA‐modSLA] or modSLA [modSLA‐modSLA]) was performed bilaterally in the upper and lower jaws of 15 beagle dogs. The animals were sacrificed after 1, 4, 7, 14, or 28 days. Tissue reactions were assessed histomorphometrically and immunohistochemically using monoclonal antibodies to transglutaminase II (angiogenesis) and osteocalcin.

Results: Although the junctional epithelium commonly was separated from M‐SLA and SLA‐SLA implants by a gap, the epithelial cells appeared to be in close contact with modA‐modSLA surfaces after 14 days of healing. Moreover, modA‐modSLA and modSLA‐modSLA groups showed a well‐vascularized subepithelial connective tissue exhibiting collagen fibers that started to extend and attach partially perpendicular to the implant surface. The highest and statistically significant mean bone‐to‐implant contact areas were observed in the modA‐modSLA and modSLA‐modSLA groups at days 7, 14, and 28.

Conclusion: Within the limits of this study, it may be concluded that soft and hard tissue integration was influenced mainly by surface hydrophilicity rather than by microtopography.
Effects of Er,Cr:YSGG Laser Irradiation on the Root Surface: Morphologic Analysis and Efficiency of Calculus Removal
Authors: Ting Chun‐Chan , Fukuda Mitsuo , Watanabe Tomohisa , Aoki Tsunehiro , Sanaoka Atushi , Noguchi Toshihide
Published: October 2007

Background: This in vitro study was performed to determine the appropriate power output setting for an erbium, chromium‐doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser used in periodontal pocket irradiation by examining the morphologic alterations of the root surfaces and the efficiency of calculus removal.

Methods: Sixty‐five non‐carious extracted human teeth were used in this study. For morphologic analysis of the root surface, the clean, single roots of 22 teeth were separated into 91 pieces, and these pieces were immersed in acrylic resin. The specimens with root‐surface exposure were prepared and divided randomly into three groups: a control group (N = 8), an irradiation without water group (no water [NW] group; N = 39), and an irradiation in water to simulate the conditions in a periodontal pocket group (in water [IW] group; N = 44). The power output settings for laser irradiation were 0.5, 1.0, 1.5, and 2.0 W for each group. The roughness (Ra), depth (Z), and width (X) of the disk specimens were determined after laser irradiation. Eight other single‐rooted teeth were examined by scanning electron microscopy (SEM) after laser irradiation under the same conditions. Thirty‐five single‐ or multirooted teeth with heavy subgingival calculus were used to test the efficiency of laser scaling. The efficiency of calculus removal was quantified by measuring the time needed to remove the calculus completely using the laser.

Results: The mean Ra and Z values in the IW group were significantly higher than in the NW group with the same power output. In addition, these values with 0.5‐ and 1.0‐W power output settings were significantly lower than with 1.5‐ and 2.0‐W settings in the NW and IW groups. No obvious morphologic differences could be found between the 0.5‐ and 1.0‐W power output specimens under SEM. Additionally, thermal alterations, i.e., carbonization or melting, were completely absent in the IW group. Regarding the efficiency of calculus removal, the 0.5‐W setting (0.11 ± 0.036 mm2/second) was significantly inferior to the 1.0‐W setting (0.27 ± 0.043 mm2/second). However, there was no significant difference between 1.0‐ and 1.5‐W (0.36 ± 0.11 mm2/second). The 2.0‐W setting (0.63 ± 0.272 mm2/second) was much more efficient but resulted in significant morphologic alterations.

Conclusions: Based on these findings, it is appropriate to use a 1.0‐W power output setting with an Er,Cr:YSGG laser for root scaling. This may be done without any conspicuous morphologic alterations to the root surface and with acceptably efficient removal of calculus.
Oral Administration of Vitamin C Prevents Alveolar Bone Resorption Induced by High Dietary Cholesterol in Rats
Authors: Sanbe Toshihiro , Tomofuji Takaaki , Ekuni Daisuke , Azuma Tetsuji , Tamaki Naofumi , Yamamoto Tatsuo
Published: October 2007

Background: A high‐cholesterol diet stimulates alveolar bone resorption, which may be induced via tissue oxidative damage. Vitamin C reduces tissue oxidative damage by neutralizing free radicals and scavenging hydroxyl radicals, and its antioxidant effect may offer the clinical benefit of preventing alveolar bone resorption in cases of hyperlipidemia. We examined whether vitamin C could suppress alveolar bone resorption in rats fed a high‐cholesterol diet.

Methods: In this 12‐week study, rats were divided into four groups: a control group (fed a regular diet) and three experimental groups (fed a high‐cholesterol diet supplemented with 0, 1, or 2 g/l vitamin C). Vitamin C was provided by adding it to the drinking water. The bone mineral density of the alveolar bone was analyzed by microcomputerized tomography. As an index of tissue oxidative damage, the 8‐hydroxydeoxyguanosine level in the periodontal tissue was determined using a competitive enzyme‐linked immunosorbent assay.

Results: Hyperlipidemia, induced by a high‐cholesterol diet, decreased rat alveolar bone density and increased the number of tartrate‐resistant acid phosphatase–positive osteoclasts. The expression of 8‐hydroxydeoxyguanosine was upregulated in the periodontal tissues. Intake of vitamin C reduced the effect of a high‐cholesterol diet on alveolar bone density and osteoclast differentiation and decreased periodontal 8‐hydroxydeoxyguanosine expression.

Conclusion: In the rat model, vitamin C suppressed alveolar bone resorption, induced by high dietary cholesterol, by decreasing the oxidative damage of periodontal tissue.
In Vitro Biologic Response of Human Bone Marrow Stromal Cells to Enamel Matrix Derivative
Authors: Guida Luigi , Annunziata Marco , Carinci Francesco , Di Feo Angelo , Passaro Irene , Oliva Adriana
Published: October 2007

Background: In vitro investigations suggest that enamel matrix derivative (EMD) may affect the biologic response of periodontal‐related cells, including osteoblasts and their precursors, the bone marrow stromal cells (BMSCs), which could play a crucial role in the regenerative process. In this study, we investigated the effects of EMD on human BMSCs.

Methods: Primary cultures of BMSCs were obtained from bone marrow samples of healthy donors. Cell proliferation and osteogenic marker expression in response to serial dilutions of EMD (12.5, 25, and 50 μg/ml) were assessed. Cell growth was measured by 3H‐thymidine incorporation and type I collagen synthesis by immunoblotting. Alkaline phosphatase (AP)‐specific activity in the early phase (7 days), in vitro mineralization by von Kossa staining and calcium quantification, and osteocalcin levels at prolonged times (3 weeks) also were evaluated.

Results: EMD stimulated BMSC growth in a dose‐dependent manner. When EMD 50 μg/ml was followed over time, the highest proliferative effect was evident at 24 hours (3.4‐fold of the control). Type I collagen level was significantly lower than the control after a 7‐day incubation with EMD 50 μg/ml. AP activity was reduced in a dose‐dependent manner down to 55% of the control. Also, the extracellular matrix mineralization decreased in EMD‐treated cells with respect to the control, whereas only a slight, not significant, decrease in osteocalcin levels was found.

Conclusions: EMD significantly increased BMSC growth and simultaneously decreased their osteogenic differentiation. The clinical efficacy of EMD in regenerating periodontal tissues can be attributed, in part, to the biologic effects exerted on the bone marrow stromal component of resident cells.
Comparison of Periodontal and Socioeconomic Status Between Subjects With Type 2 Diabetes Mellitus and Non‐Diabetic Controls
Authors: Javed Fawad , Näsström Karin , Benchimol Daniel , Altamash Mohammad , Klinge Björn , Engström Per‐Erik
Published: October 2007

Background: The association among periodontal conditions, socioeconomic status (SES), and diabetes has been reported. However, there is a lack of published data comparing periodontal conditions among individuals with poorly controlled type 2 diabetes mellitus (T2D). The aim of the present study was to compare the periodontal conditions and SES between subjects with T2D and non‐diabetic controls.

Methods: A total of 75 (31 males and 44 females) individuals with T2D (62 poorly controlled and 13 well‐controlled) and 99 non‐diabetic patients (healthy controls; 51 males and 48 females) participated in the study. Plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were investigated. Random blood glucose level was recorded. Premolar and molar marginal bone loss (MBL) was measured digitally on scanned orthopantomograms.

Results: Individuals with poorly controlled T2D had increased MBL in molars and maxillary premolars (P <0.05) compared to individuals with well‐controlled T2D. PI, BOP, and PD of 4 to <6 mm were increased in individuals with poorly controlled T2D compared to those with well‐controlled T2D (P <0.001). There was no difference between the diabetic groups when PD was ≥6 mm. Individuals with poorly controlled T2D had a lower SES compared to patients with well‐controlled T2D (P <0.05). Illiteracy and the number of missing teeth were not different between the groups.

Conclusions: Radiologic and clinical indicators of periodontal destruction were increased in individuals with poorly controlled T2D. Low SES aggravated the periodontal condition in individuals with T2D.