bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Implant Connection Type on the Biomechanical Environment of Immediately Placed Implants – CT‐Based Nonlinear, Three‐Dimensional Finite Element Analysis
Authors: Pessoa Roberto S. , Muraru Luiza , Júnior Elcio Marcantonio , Vaz Luis Geraldo , Sloten Jos Vander , Duyck Joke , Jaecques Siegfried V.N. 
Published: May 2009

ABSTRACTPurpose: The purpose of the present study was to evaluate the biomechanical environment of immediately placed implants, before and after osseointegration, by comparing three different implant‐abutment connection types.Materials and Methods: A computer tomography‐based finite element model of an upper central incisor extraction socket was constructed containing implants with either external hex, internal hex, or Morse‐taper connection. Frictional contact elements were used in the bone, implant, abutment, and abutment screw interfaces in the immediately placed simulations. In osseointegrated simulations, the repair of bone alveolar defect and a glued bone‐to‐implant interface were assumed. By analysis of variance, the influence was assessed of connection type, clinical situation, and loading magnitude on the peak equivalent strain in the bone, peak von Mises stress in the abutment screw, bone‐to‐implant relative displacement, and abutment gap.Results: The loading magnitudes had a significant contribution, regardless of the assessed variable. However, the critical clinical situation of an immediately placed implant itself was the main factor affecting the peak equivalent strain in the bone and bone‐to‐implant displacement. The largest influence of the connection type in this protocol was seen on the peak equivalent stress in the abutment screw. On the other hand, a higher influence of the various connection types on bone stress/strain could be noted in osseointegrated simulations.Conclusions: The implant‐abutment connection design did not significantly influence the biomechanical environment of immediately placed implants. Avoiding implant overloading and ensuring a sufficient initial intraosseous stability are the most relevant parameters for the promotion of a safe biomechanical environment in this protocol.
Modular Preoperative Planning Software for Computer‐Aided Oral Implantology and the Application of a Novel Stereolithographic Template: A Pilot Study
Authors: Chen Xiaojun , Yuan Jianbing , Wang Chengtao , Huang Yuanliang , Kang Lu 
Published: May 2009

ABSTRACTPurpose: In the field of oral implantology, there is a trend toward computer‐aided implant surgery, especially the application of computerized tomography (CT)‐derived surgical templates. However, because of relatively unsatisfactory match between the templates and receptor sites, conventional surgical templates may not be accurate enough for the severely resorbed edentulous cases during the procedure of transferring the preoperative plan to the actual surgery. The purpose of this study is to introduce a novel bone–tooth‐combined‐supported surgical guide, which is designed by utilizing a special modular software and fabricated via stereolithography technique using both laser scanning and CT imaging, thus improving the fit accuracy and reliability.Materials and Methods: A modular preoperative planning software was developed for computer‐aided oral implantology. With the introduction of dynamic link libraries and some well‐known free, open‐source software libraries such as Visualization Toolkit (Kitware, Inc., New York, USA) and Insight Toolkit (Kitware, Inc.) a plug‐in evolutive software architecture was established, allowing for expandability, accessibility, and maintainability in our system. To provide a link between the preoperative plan and the actual surgery, a novel bone–tooth‐combined‐supported surgical template was fabricated, utilizing laser scanning, image registration, and rapid prototyping. Clinical studies were conducted on four partially edentulous cases to make a comparison with the conventional bone‐supported templates.Results: The fixation was more stable than tooth‐supported templates because laser scanning technology obtained detailed dentition information, which brought about the unique topography between the match surface of the templates and the adjacent teeth. The average distance deviations at the coronal and apical point of the implant were 0.66 mm (range: 0.3–1.2) and 0.86 mm (range: 0.4–1.2), and the average angle deviation was 1.84° (range: 0.6–2.8°).Conclusions: This pilot study proves that the novel combined‐supported templates are superior to the conventional ones. However, more clinical cases will be conducted to demonstrate their feasibility and reliability.
Influence of the Connector and Implant Design on the Implant–Tooth‐Connected Prostheses
Authors: Da Silva Edmar Ferreira , Pellizzer Eduardo Piza , Quinelli Mazaro José Vitor , Garcia Júnior Idelmo Rangel 
Published: May 2009

ABSTRACTPurpose: The purpose of this study was to evaluate stress transfer patterns between implant–tooth‐connected prostheses comparing rigid and semirigid connectors and internal and external hexagon implants.Materials and Methods: Two models were made of photoelastic resin PL‐2, with an internal hexagon implant of 4.00 × 13 mm and another with an external hexagon implant of 4.00 × 13 mm. Three denture designs were fabricated for each implant model, incorporating one type of connection in each one to connect implants and teeth: 1) welded rigid connection; 2) semirigid connection; and 3) rigid connection with occlusal screw. The models were placed in the polariscope, and 100‐N axial forces were applied on fixed points on the occlusal surface of the dentures.Results: There was a trend toward less intensity in the stresses on the semirigid connection and solid rigid connection in the model with the external hexagon; among the three types of connections in the model with the internal hexagon implant, the semirigid connection was the most unfavorable one; in the tooth–implant association, it is preferable to use the external hexagon implant.Conclusions: The internal hexagon implant establishes a greater depth of hexagon retention and an increase in the level of denture stability in comparison with the implant with the external hexagon. However, this greater stability of the internal hexagon generated greater stresses in the abutment structures. Therefore, when this association is necessary, it is preferable to use the external hexagon implant.
Long‐Term Follow‐Up on Soft and Hard Tissue Levels Following Guided Bone Regeneration Treatment in Combination with a Xenogeneic Filling Material: A 5‐Year Prospective Clinical Study
Authors: Dahlin C. , Simion M. , Hatano N. 
Published: May 2009

ABSTRACTPurpose: In the present prospective study, bone augmentation by guided bone regeneration (GBR) in combination with bovine hydroxyapatite (BHA) as filling material was evaluated with regard to soft and hard tissue stability over time.Materials and Methods: Implant survival, radiologic bone level (marginal bone level [MBL]), and clinical soft tissue parameters (marginal soft tissue level [MSTL]) were observed. Twenty patients received a total of 41 implants (Brånemark System, Nobel Biocare, Göteborg, Sweden) in conjunction with GBR treatment. The end point of the study was after 5 years following implant placement.Results: The cumulative implant survival rate was 97.5% corresponding to one implant failure. The radiologic evaluation of the MBL demonstrated a crestal bone height above the level of the fixture head. The bone height decreased from −3.51 to −2.38 mm (p < .001). The MSTL was −1.52 mm at baseline and −1.15 mm at the 5‐year follow‐up (p < .04) demonstrating a stable submucosal crown margin throughout the study period.Conclusion: GBR treatment in combination with a xenogeneic filling material (BHA) is a viable treatment option in order to maintain stable hard and soft tissue levels in conjunction with augmentative procedure related to oral implant treatment.
Three Tumor Patients with Total Maxillectomy Rehabilitated with Implant‐Supported Frameworks and Maxillary Obturators: A Follow‐Up Report
Authors: Örtorp Anders 
Published: May 2009

ABSTRACTBackground: Few reports are available on treatment using implant‐supported frameworks with maxillary obturators after total maxillectomy on tumor patients.Purpose: To describe, evaluate, and report the clinical and radiographic performance of implant‐supported frameworks and maxillary obturators after maxillectomy during the first years of function.Materials and Methods: Three patients with cancer in the maxillary region treated by total maxillectomy were rehabilitated. Seventeen dental and two craniofacial implants were installed, and the patients each received implant‐supported, screw‐retained, three‐unit frameworks with a U‐shaped bar and obturators retained by four magnetic attachments. Clinical and radiographic data were collected up to 7 years of follow‐up.Results: The frequency of complications was low. Two craniofacial implants and one dental implant were loose and removed at abutment connection. No implants were lost after framework connection, and the mean marginal bone loss was small.Conclusion: Within the limitations of this report, dental implants are useful for rehabilitation of total maxillectomy patients, and a three‐unit, screw‐retained, implant‐supported framework with maxillary obturator retained by magnetic attachment is a successful treatment concept for this patient group.
Bacterial Persistence in Dentoalveolar Bone Following Extraction: A Microbiological Study and Implications for Dental Implant Treatment
Authors: Nelson Stephen , Thomas Graham 
Published: May 2009

ABSTRACTBackground: The microbiological status of apparently healed alveolar bone implant sites is unknown. Implant success may be compromised by site‐specific persistence of bacterial biofilm co‐aggregations contaminating healed alveolar bone.Purpose: The purpose of the present study was to investigate whether extraradicular infection can persist in apparently healed alveolar bone and to develop a surgical debridement strategy that favors implant osseointegration.Materials and Methods: The study was conducted on 32 private practice patients. Seventy‐seven microbiological samples were taken from 16 pre‐implant extraction sockets, 56 healed post‐extraction osteotomies at fixture placement, and five failed fixtures. Two of the healed osteotomy samples were healed retreatment sites. Tissue fluid and bone samples were analyzed by either anaerobic/aerobic culturing or DNA molecular techniques. All patients were treated ad modum Brånemark, with a two‐stage sterile surgical procedure.A search of the medical and dental literature revealed no evidence‐based or best practice recommendations for the use of debridement in implant therapy. Thus, we developed a new technique for the debridement of alveolar bone found to be contaminated by persistent biofilm or planktonic bacteria.Results: The results of the microbiological analysis of 77 bone and effusion samples from 47 implant sites of the 32 patients showed that overall, 32% (n = 25) had bacteria present in the sample. In 16 pre‐implant extraction sockets, 69% of samples were positive for the presence of bacteria (n = 11). Of 56 osteotomies with a minimum 3‐month healing at fixture placement, 21% revealed a positive culture (n = 12). Two‐stage failed fixtures had 100% positive cultures (n = 5) and it was evident from radiographs that all of these failed fixtures had the apical ends close to the former tooth root end.Based on these findings, we have developed a microbiologically based surgical debridement strategy to successfully re‐treat early infective failures and to place successful two‐stage fixtures.Conclusion: Bacteria can persist as a contaminant in apparently healed alveolar bone following extraction of teeth with apical or radicular pathosis. A new technique for surgical debridement to reduce and limit this bacterial contamination has been described.
Understanding Kripke's Puzzles about Belief
Authors: McGlone Michael 
Published: May 2009

AbstractIn his famous 1979 article ‘A Puzzle About Belief’ Saul Kripke presents two puzzles regarding belief attribution, and he uses them to cast doubt on classical substitution arguments against the Millian view that a proper name has a ‘denotation’ (or reference) but no ‘connotation’ (or sense). In this article, I present Kripke's puzzles in what I take to be their most revealing form, discuss their relevance to the abovementioned arguments, briefly survey the ways in which philosophers have responded to these puzzles, and call attention to some issues related to the puzzles that have yet to receive the consideration they deserve.
Declining In‐Hospital Mortality and Increasing Heart Failure Incidence in Elderly Patients With First Myocardial Infarction
Authors: Harris Scott , Tepper David , Ip Randy 
Published: May 2009

Abstract.  Objectives.  The purpose of this study was to examine the long‐term incidence of heart failure (HF) in elderly patients with myocardial infarction (MI). Background.  In‐hospital HF is common after MI and is associated with poor short‐term prognosis. Limited data exist concerning the long‐term incidence or prognosis of HF after MI, particularly in the era of coronary revascularization. Methods.  A population‐based cohort of 7733 patients 65 years and older hospitalized for a first MI (International Classification of Diseases, 9th Revision Clinical Modification code 410.x) and without a prior history of HF was established between 1994 and 2000 in Alberta, Canada, and followed up for 5 years. Results.  During the index MI hospitalization, 2831 (37%) MI patients were diagnosed with new HF and 1024 (13%) died. Among hospital survivors who did not have HF during their index hospitalization (n=4291), an additional 3040 patients (71%) developed HF by 5 years, 64% of which occurred in the first year. In total, 5871 (76%) elderly patients who survived their first MI developed HF over 5 years. Among those who survived the index hospitalization, the 5‐year mortality rate was 39.1% for those with HF during the index MI hospitalization compared with 26.7% among those without HF (P<.0001) during the index MI hospitalization. Over the study period, the 5‐year mortality rate after MI decreased by 28%, whereas the 5‐year rate of HF increased by 25%. Conclusions.  In this large cohort of elderly patients without a history of HF, HF developed in three‐quarters in the 5 years after their first MI; this proportion increased over time as peri‐MI mortality rates declined. New‐onset HF significantly increases the mortality risk among these patients.—Ezekowitz JA, Kaul P, Bakal JA, et al. Declining in‐hospital mortality and increasing heart failure incidence in elderly patients with first myocardial infarction.J Am Coll Cardiol. 2009;53(1):21–23.
The Nature of Contemporary Prejudice: Insights from Aversive Racism
Authors: Pearson Adam R. , Dovidio John F. , Gaertner Samuel L. 
Published: May 2009

AbstractWithin the United States, declines in the overt expression of racial prejudice over several decades have given way to near universal endorsement of the principles of racial equality as a core cultural value. Yet, evidence of persistent and substantial disparities between Blacks and Whites remain. Here, we review research that demonstrates how the actions of even well‐intentioned and ostensibly non‐prejudiced individuals can inadvertently contribute to these disparities through subtle biases in decision making and social interactions. We argue that current racial attitudes of Whites toward Blacks in the United States are fundamentally ambivalent, characterized by a widespread contemporary form of racial prejudice, aversive racism, that is manifested in subtle and indirect ways, and illustrate its operation across a wide range of settings, from employment and legal decisions, to group problem‐solving and everyday helping behavior. We conclude by describing research aimed at combating these biases and identify new avenues for future research.
Habermas and Social Movement Theory
Authors: Edwards Gemma 
Published: May 2009

AbstractThis article outlines Habermas’ social movement–related ideas and reviews the critical reception of them from within critical theory and social movement studies more widely. Criticism of Habermas’ explanation of the new social movements has been wide‐ranging and persuasive. There have however been some contemporary critical engagements with Habermas’ ideas within social movement studies. The direction they take suggests (1) the concept of ‘colonisation’ finds political relevance in the twenty‐first century context of global capitalism and resistance to neo‐liberal policies; (2) that recent engagements with Habermas loosely unite in a concern with the ‘applied turn’ in critical theory; and (3) there is some potential for aspects of Habermas’ theory to be used in ways that make him capable of engaging in dialogue with the current concerns of social movement theory.
Contributions of the National Incident‐Based Reporting System to Substantive Knowledge in Criminology: A Review of Research
Authors: Roberts Aki 
Published: May 2009

AbstractThe National Incident‐Based Reporting System (NIBRS) data have been available to the research community for about a decade. The advantages of NIBRS over other official statistics such as summary Uniform Crime Reports, Supplementary Homicide Reports, and the National Crime Victimization Survey have contributed to better evaluation of a number of theoretical perspectives in criminology and criminal justice, and have helped in suggesting possible policy implications. This paper reviews studies using the NIBRS data in the areas of crime clearance, crime rates disaggregated by situational context (including domestic violence, race‐specific crime, and gun crime), and lethal and non‐lethal outcomes of violent encounters. The paper also discusses limitations of the NIBRS data and cautions for its use, along with future research possibilities.
Gender and Employment: A Global Lens on Feminist Analyses and Theorizing of Labor Markets
Authors: Gottfried Heidi 
Published: May 2009

AbstractThis review of feminist analyses and theorizing of labor markets uses a global lens to reveal the forces shaping gender inequality. The review focuses on the increasing dominance of services primarily in the liberal market economies of the United States and the United Kingdom along with examples from Asia where restructuring has shifted locations of work and affected new ways of working by a diverse and mobile workforce. Labor market restructuring through commodification of care, outsourcing of household tasks and informalization of employment affects the complexity of relationships between and the interconnectedness of social inequalities transnationally and in global cities. Place matters when analyzing how service employment alters divisions of labor and how these labor market changes are gendered. Global restructuring not only poses new challenges but also creates new opportunities for mobilization around a more robust notion of equality.
Novel
pfdhps
Haplotypes among Imported Cases of
Plasmodium falciparum
Malaria in the United Kingdom
Authors: Sutherland Colin J. , Fifer Helen , Pearce Richard J. , bin Reza Faisal , Nicholas Meredydd , Haustein Thomas , Njimgye-Tekumafor Njah E. , Doherty Justin F. , Gothard Philip , Polley Spencer D. , Chiodini Peter L. 
Published: May 2009

ABSTRACT

Treatment of acute malaria caused by
Plasmodium falciparum
may include long-half-life drugs, such as the antifolate combination sulfadoxine-pyrimethamine (SP), to provide posttreatment chemoprophylaxis against parasite recrudescence or delayed emergence from the liver. An unusual case of
P. falciparum
recrudescence in a returned British traveler who received such a regimen, as well as a series of 44 parasite isolates from the same hospital, was analyzed by PCR and direct DNA sequencing for the presence of markers of parasite resistance to chloroquine and antifolates. The index patient harbored a mixture of wild-type and resistant
pfdhfr
and
pfdhps
alleles upon initial presentation. During his second malaria episode, he harbored only resistant parasites, with the haplotypes IRNI (codons 51, 59, 108, and 164) and SGEAA (codons 436, 437, 540, 581, and 613) at these two loci, respectively. Analysis of isolates from 44 other patients showed that the
pfdhfr
haplotype IRNI was common (found in 81% of cases). The SGEAA haplotype of
pfdhps
was uncommon (found only in eight cases of East African origin [17%]). A previously undescribed mutation, I431V, was observed for seven cases of Nigerian origin, occurring as one of two haplotypes, VAGKGS or VAGKAA. The presence of this mutation was also confirmed in isolates of Nigerian origin from the United Kingdom Malaria Reference Laboratory. The presence of the
pfdhps
haplotype SGEAA in
P. falciparum
parasites of East African origin appears to compromise the efficacy of treatment regimens that include SP as a means to prevent recrudescence. Parasites with novel
pfdhps
haplotypes are circulating in West Africa. The response of these parasites to chemotherapy needs to be evaluated.
Structural Basis of APH(3′)-IIIa-Mediated Resistance to N1-Substituted Aminoglycoside Antibiotics
Authors: Fong Desiree H. , Berghuis Albert M. 
Published: May 2009

ABSTRACT

Butirosin is unique among the naturally occurring aminoglycosides, having a substituted amino group at position 1 (N1) of the 2-deoxystreptamine ring with an (
S
)-4-amino-2-hydroxybutyrate (AHB) group. While bacterial resistance to aminoglycosides can be ascribed chiefly to drug inactivation by plasmid-encoded aminoglycoside-modifying enzymes, the presence of an AHB group protects the aminoglycoside from binding to many resistance enzymes, and hence, the antibiotic retains its bactericidal properties. Consequently, several semisynthetic N1-substituted aminoglycosides, such as amikacin, isepamicin, and netilmicin, were developed. Unfortunately, butirosin, amikacin, and isepamicin are not resistant to inactivation by 3′-aminoglycoside
O
-phosphotransferase type IIIa [APH(3′)-IIIa]. We report here the crystal structure of APH(3′)-IIIa in complex with an ATP analog, AMPPNP [adenosine 5′-(β,γ-imido)triphosphate], and butirosin A to 2.4-Å resolution. The structure shows that butirosin A binds to the enzyme in a manner analogous to other 4,5-disubstituted aminoglycosides, and the flexible antibiotic-binding loop is key to the accommodation of structurally diverse substrates. Based on the crystal structure, we have also constructed a model of APH(3′)-IIIa in complex with amikacin, a commonly used semisynthetic N1-substituted 4,6-disubstituted aminoglycoside. Together, these results suggest a strategy to further derivatize the AHB group in order to generate new aminoglycoside derivatives that can elude inactivation by resistance enzymes while maintaining their ability to bind to the ribosomal A site.
Antiretroviral Drug Resistance Surveillance among Treatment-Naive Human Immunodeficiency Virus Type 1-Infected Individuals in Angola: Evidence for Low Level of Transmitted Drug Resistance
Authors: Bártolo Inês , Rocha Cheila , Bartolomeu José , Gama António , Fonseca Marlene , Mendes Ana , Cristina Filipa , Thamm Sven , Epalanga Marta , Silva Patrícia Cavaco , Taveira Nuno 
Published: May 2009

ABSTRACTThe prevalence of transmitted human immunodeficiency virus type 1 drug resistance in Angola in 2001 in 196 untreated patients was investigated. All subtypes were detected, along with unclassifiable and complex recombinant strains. Numerous new polymorphisms were identified in the reverse transcriptase and protease. Two (1.6%) unrelated patients harbored nucleoside reverse transcriptase inhibitor- and nonnucleoside reverse transcriptase inhibitor-resistant viruses (mutations: M41L, D67N, M184V, L210W, T215Y or T215F, and K103N). Continued surveillance of drug resistance is required for maximization of ART efficacy in Angola.