bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implant–abutment interface design affects fatigue and fracture strength of implants
Authors: Steinebrunner Lars , Wolfart Stefan , Ludwig Klaus , Kern Matthias 
Published: November 2008

AbstractObjectives: Failures of implant–abutment connections are relatively frequent clinical problems. The aim of this study was to evaluate the influence of long‐term dynamic loading on the fracture strength of different implant–abutment connections.Material and methods: Six implant systems were tested: two systems with external connections (Brånemark, Compress) and four systems with internal connections (Frialit‐2, Replace‐Select, Camlog, Screw‐Vent). Fracture strength was tested in two subgroups for each system: one subgroup with (dyn) and the other without prior dynamic loading (contr). Each subgroup consisted of eight specimens with standard implant–abutment combinations for single molar crowns. Dynamic loading was performed in a two‐axis chewing simulator with 1,200,000 load cycles at 120 N.Results: Median fracture strengths in Newton (N) and 25th and 75th percentiles [in brackets] were: Brånemark: dyn=729 [0;802]/contr=782 [771;811], Frialit‐2: dyn=0 [0;611]/contr=887 [798;941], Replace‐Select: dyn=1439 [1403;1465]/contr=1542 [1466;1623], Camlog: dyn=1482 [1394;1544]/contr=1467 [1394;1598], Screw‐Vent: dyn=0 [0;526]/contr=780 [762;847] and Compress: dyn=818[0;917]/contr=1008 [983;1028]. In some dyn subgroups, failures of the implant–abutment connection occurred already during dynamic loading: three specimens of the Brånemark and Compress groups and six specimens of the Screw‐Vent and the Frialit‐2 groups failed during dynamic loading. Statistically significant differences (P≤0.05) in fracture strength could be found between groups with different connection designs.Conclusion: Implant systems with long internal tube‐in‐tube connections and cam–slot fixation showed advantages with regard to longevity and fracture strength compared with systems with shorter internal or external connection designs.
New safety margins for chin bone harvesting based on the course of the mandibular incisive canal in CT
Authors: Pommer Bernhard , Tepper Gabor , Gahleitner André , Zechner Werner , Watzek Georg 
Published: November 2008

AbstractObjectives: Altered pulp sensitivity of anterior lower teeth is a frequent finding following chin bone harvesting. Persistent loss of tooth sensitivity has been reported in up to 20% of the patients. The aim of this study was to evaluate current recommendations for the location of the harvest zone with respect to the course of the mandibular incisive canal (MIC), the intrabony continuation of the mandibular canal mesial to the mental foramen.Material and methods: On computed tomographic (CT) scans of 50 dentate mandibles, the MIC was located and its distance to the root apices, to the labial bony surface, and to the inferior margin of the mandible was assessed. The risk of nerve injury and the percentage of patients suitable for chin bone grafting were calculated.Results: Respecting current recommendations for chin bone grafting, the content of the MIC was endangered in 57% of the CTs. Therefore, new safety margins are suggested: the chin bone should be harvested at least 8 mm below the tooth apices with a maximum harvest depth of 4 mm.Conclusions: Applying the new safety recommendations and proper patient selection in chin bone harvesting could reduce the risk of altered postoperative tooth sensitivity due to injury of the mandibular incisive nerve.
Optimisation of the hydrogen peroxide pre‐treatment of titanium: surface characterisation and protein adsorption
Authors: Nagassa M. E. , Daw A. E. , Rowe W. G. , Carley A. , Thomas D. W. , Moseley R. 
Published: November 2008

AbstractBackground: Researchers have attempted to enhance titanium osseointegration by modifying its surface properties, including via H2O2 pre‐treatment, with reported treatment regimes varying from minutes/hours, to weeks.Objective: This study examined the effects of various H2O2 treatments on titanium surface topography/roughness, chemical composition/oxide thickness, hydrophilicity and plasma protein adsorption.Materials and methods: Titanium discs were treated with 30% H2O2 for 0–24 h or 1–4 weeks and subjected to atomic force microscopy (AFM), scanning electron microscopy (SEM), profilometry, X‐ray photon spectroscopy and contact angle analysis. For protein adsorption, whole plasma and FITC‐conjugated serum albumin were added to 0–24 h and  1–4 week H2O2‐treated discs and examined by SEM and fluorescence microscopy, respectively.Results: AFM, SEM and profilometry demonstrated that 1–6 h H2O2‐treated discs exhibited subtle alterations in surface topography/roughness at the nanometre scale, although 24 h and 1–4 week H2O2‐treated discs exhibited much greater increases in surface roughness, in the micrometre range. Maximal increases in surface oxide thickness and chemical modification were identified between 1 h–4 weeks and 3 h–4 weeks, respectively, although no increases in oxygen/titanium (O1s : Ti2p) molar ratio or in hydrophilicity were evident. Plasma and serum albumin adsorption increased on 1–24 h H2O2‐treated discs, with further increases on 1–4 week H2O2‐treated discs.Conclusions: Based upon the present data and previous findings, this study supports the concept that surface topography/roughness and oxide composition/thickness, are more significantly modified by H2O2 treatment and more influential to protein adsorption than hydrophilicity. Additionally, it can be hypothesized that the 24 h H2O2 treatment of titanium surfaces, which induced micrometre scale changes in roughness and protein adsorption, to those associated with enhanced osteoblast attachment/behaviour, mineralisation and subsequent implant osseointegration, would be most beneficial.
Periodontal ligament cell sheet promotes periodontal regeneration in athymic rats
Authors: Flores Mara Gomez , Yashiro Reiko , Washio Kaoru , Yamato Masayuki , Okano Teruo , Ishikawa Isao 
Published: November 2008

AbstractAim: The primary goal of periodontal treatment is regeneration of the periodontium. Current theories suggest that the periodontal ligament (PDL) cells have the capacity to participate in restoring connective and mineralized tissues, when appropriately triggered. We evaluated whether human PDL cell sheets could reconstruct periodontal tissue.Material and Methods: To obtain the cell sheet, human PDL cells were cultured on temperature‐responsive culture dishes with or without osteogenic differentiation medium. The cell sheets were transplanted on periodontal fenestration defects of immunodeficient rats. Forty rats were divided in two groups: in one group, cell sheets cultured with control medium were transplanted and in the other, cell sheets cultured with osteogenic differentiation medium were transplanted. The defects were analysed histologically and histomorphologically after healing.Results: Most of the experimental group exhibited a new cementum‐like layer and new attachment of collagen fibres to the layer. Histomorphological analyses indicated significant periodontal regeneration. The control group revealed dense extracellular matrix and fibre formation, but an obvious cementum layer was not observed.Conclusions: Transplanted PDL cell sheets cultured with osteogenic differentiation medium induced periodontal regeneration containing an obvious cementum layer and Sharpey's fibres. Thus, the method could be feasible as a new therapeutic approach for periodontal regeneration.
Replacement therapy for periodontitis: pilot radiographic evaluation in a dog model
Authors: Nackaerts Olivia , Jacobs Reinhilde , Quirynen Marc , Rober Marleen , Sun Yi , Teughels Wim 
Published: November 2008

AbstractAim: The aim of this study was to radiologically evaluate the impact of replacement therapy by monitoring bone density changes and alveolar bone level in periodontal pockets in a dog model.Material and Methods: Eight male beagle dogs with moderate periodontitis were enrolled in this split‐mouth, double‐blind randomized trial with ethical approval. Periodontal defects were surgically created bilaterally in the lower jaw. Four months later, the defects were randomly assigned to initial therapy (scaling and root planing) alone (control sites), or combined with multiple subgingival application of beneficial species. Intra‐oral follow‐up radiography was performed at this stage and 3 months later to verify the treatment effect.Results: The bone density within periodontal pockets treated with beneficial bacteria improved significantly after 12 weeks, while this was non‐significant for the control pockets, receiving a single root planing at baseline. There was a significant increase in the bone level at the end of the study for the pockets receiving beneficial bacteria. Again, no significance was noted for the control pockets.Conclusions: This pilot study indicates the potential effect of a subgingival application of beneficial species in periodontal pockets, and illustrates the strength of standardized follow‐up radiography to evaluate the effects of different treatment strategies on bone re‐modelling.
TLR4 and IL‐18 gene variants in aggressive periodontitis
Authors: Noack Barbara , Görgens Heike , Lorenz Katrin , Ziegler Andreas , Hoffmann Thomas , Schackert Hans Konrad 
Published: November 2008

AbstractAim: We aimed to assess the association of different genotypes with increased aggressive periodontitis susceptibility by studying functional relevant variants in the pathogen‐recognition receptor Toll‐like receptor 4 (TLR4) and variants in the promoter region of the pro‐inflammatory cytokine interleukin‐18 (IL‐18).Material and Methods: One hundred and eleven patients with aggressive periodontitis and 80 periodontally healthy controls were genotyped for four functional variants in the TLR4 gene (c.896A>G and c.1196C>T) and in the IL‐18 promoter (c.−368G>C and c.−838C>A). The genotype and allele frequencies, as well as the frequency of combined genotypes were compared between study groups.Results: There were no statistical differences in genotype and allele frequencies within the four variants between the groups. All study subjects were further classified into carriers and non‐carriers of at least one variant of both genes. The logistic regression analysis adjusted for gender and smoking showed no association between carrier status of at least one variant of both genes and periodontal status (OR=1.41, 95% CI: 0.43–4.70).Conclusions: Our results reject the hypothesis that functionally relevant IL‐18 and TLR4 gene mutations have a major effect on aggressive periodontitis susceptibility alone or in combination.
Objective measurement of periocular pigmentation
Authors: Lee Janet Agnes , Osmanovic Smajo , Viana Marlos A. G. , Kapur Rashmi , Meghpara Beeran , Edward Deepak P. 
Published: November 2008

Purpose: To evaluate the Minolta CR‐400 chromameter in objectively measuring periocular/facial pigmentation in subjects of different ethnicities.Methods: The CR‐400 was used to obtain skin color measurements from 75 African‐American, Caucasian and Hispanic subjects in 16 facial and periocular locations. Comparisons between ethnic and Fitzpatrick groups and instrument reliability were analyzed.Results: Significant differences in L* were observed among all three ethnic groups, while values a* and b* were less sensitive to differences in pigmentation. Comparison between Fitzpatrick groups again identified value L* as being the most sensitive, demonstrating significant differences between the more heavily pigmented groups. The 16 facial locations measured were found to be statistically similar to each other, and the chromameter demonstrated excellent inter‐ and intra‐instrument reliability.Conclusions: The Minolta CR‐400 chromameter reliably measures facial pigmentation and can be useful for studies evaluating changes in skin pigmentation. Value L* is the parameter that is most sensitive to differences between ethnic and Fitzpatrick groups. Overlap between groups was observed, demonstrating that in future studies, each individual must serve as their own control when monitoring changes in pigmentation. The similarity between all the locations tested demonstrates uniformity of facial pigmentation within an individual.
Sun protection factor persistence during a day with physical activity and bathing
Authors: Bodekær Mette , Faurschou Annesofie , Philipsen Peter Alshede , Wulf Hans Christian 
Published: November 2008

Background/purpose: The persistence of sunscreens during a day with physical activity and bathing is often debated. We wished to examine the durability of the protection achieved by one sunscreen application.Methods: Seven areas were marked on the back of 24 volunteers. One area was phototested to determine UV sensitivity. Six areas were treated with either an organic or an inorganic sunscreen (2 mg/cm2). The participants performed physical activities, were exposed to a hot environment and bathing during 8 h and were phototested with ultraviolet‐B (UVB) radiation 30 min, 4 and 8 h after sunscreen application. The minimal erythema dose (MED) was determined 24 h after irradiation. The sun protection factor (SPF) was calculated, as MED on protected skin/MED on unprotected skin.Results: The SPFs of the inorganic and organic sunscreen, respectively, were reduced by 38% and 41% after 4 h and by 55% and 58% after 8 h.Conclusion: One application of either an inorganic or an organic sunscreen reduced the erythema caused by UVB during a day with physical activity and bathing. After 8 h the sunscreens still provided approximately 43% of the initial protective effect. This might simulate what happens during a day at the beach.
Riboflavin‐mediated cellular photoinhibition of cisplatin‐induced oxidative DNA breakage in mice epidermal keratinocytes
Authors: Husain Eram , Naseem Imrana 
Published: November 2008

Background/purpose: Cisplatin is one of the most effective chemotherapeutic agents used in the treatment of various kinds of malignant tumors. A major drawback associated with cisplatin chemotherapy is its cytotoxicity/genotoxicity towards normal tissues. The cytotoxicity has been attributed, in part, to the oxidative stress generated by the drug. Riboflavin is a micronutrient known for its photosensitization characteristics. Owing to the emergence of photodynamic therapy as a modality for the treatment of solid tumors and other accessible lesions in terms of opthalmic, dermatological, cardiovascular and urological diseases, the therapeutic window of riboflavin as a sensitizer has been used to avoid the toxic side effects of cisplatin.Methods & results: Using mice epidermal keratinocytes and comet assay, we show that photochemically activated riboflavin is able to prevent oxidative cellular DNA breakage induced by cisplatin. Irradiation of cells exposed to cisplatin resulted in a dose‐dependent increase in the frequency of strand breaks in cellular DNA. Sequential incubation of keratinocytes with riboflavin and cisplatin followed by irradiation led to a significant decrease in strand breakage and reduced the generation of reactive oxygen species.Conclusion: Our results suggest that cisplatin‐induced genotoxicity may be blunted or reduced by using riboflavin as a photosensitizer.
Association of aplastic anaemia and Fanconi's disease with HLA‐DRB1 alleles
Authors: Yari F. , Sobhani M. , Vaziri M. Z. , Bagheri N. , Sabaghi F. , Talebian A. 
Published: November 2008

SummaryOne of the most fascinating areas of research within the field of histocompatibility at present time concerns an observation that a major human histocompatibility system, human leucocyte antigen (HLA), is deeply involved in the development of a great number of diseases. Major histocompatibility complex is the most polymorphic system in the genome of different species. Recognition of HLA alleles could be useful in transplantation and disease studies. Genetic construct of HLA DRB1 was studied in Iranian normal populations and patients with aplastic anaemia and Fanconi's disease. DNA was extracted from the whole blood of 466 normal, 35 aplastic anaemia and 10 Fanconi's individuals. Then DRB1 gene polymorphism was studied by polymerase chain reaction‐sequence‐specific primer method. The HLA DRB1 gene analysis showed increase of DRB1*07 in aplastic anaemia patients compared to normal population (P = 0.02). According to this study, the frequency of DRB1*07 in normal individuals was 8.3, and in aplastic anaemia patients, 15.7%. Additionally, the frequency of DRB1*04 in normal, aplastic anaemia and Fanconi's individuals was 10, 5.7 and 20%, respectively. Our results of investigation showed correlation between some HLA alleles with the studied diseases. We reported the frequency of various DR types in aplastic and Fanconi's patients. This study could imply the possible role of HLA‐DRB1*07 in the incidence of aplastic anaemia. Moreover, the frequency of DRB1*04, DRB1*03 and DRB1*15 alleles showed intermediate correlation with Fanconi's anaemia.
Galactic dynamo action in presence of stochastic α and shear
Authors: Sur Sharanya , Subramanian Kandaswamy 
Published: November 2008

AbstractUsing a one-dimensional αω-dynamo model appropriate to galaxies, we study the possibility of dynamo action driven by a stochastic α-effect and shear. To determine the field evolution, one needs to examine a large number of different realizations of the stochastic component of α. The net growth or decay of the field depends not only on the dynamo parameters but also on the particular realization, the correlation time of the stochastic α compared to turbulent diffusion time-scale and the time over which the system is evolved. For dynamos where both a coherent and fluctuating α are present, the stochasticity of α can help alleviate catastrophic dynamo quenching, even in the absence of helicity fluxes. One can obtain final field strengths up to a fraction ∼0.01 of the equipartition field Beq for dynamo numbers |D| ∼ 40, while fields comparable to Beq require much larger degree of α-fluctuations or shear. This type of dynamo may be particularly useful for amplifying fields in the central regions of disc galaxies.
Inverse Modeling Approach to Allogenic Karst System Characterization
Authors: Dörfliger N. , Fleury P. , Ladouche B. 
Published: November 2008

AbstractAllogenic karst systems function in a particular way that is influenced by the type of water infiltrating through river water losses, by karstification processes, and by water quality. Management of this system requires a good knowledge of its structure and functioning, for which a new methodology based on an inverse modeling approach appears to be well suited. This approach requires both spring and river inflow discharge measurements and a continuous record of chemical parameters in the river and at the spring. The inverse model calculates unit hydrographs and the impulse responses of fluxes from rainfall hydraulic head at the spring or rainfall flux data, the purpose of which is hydrograph separation. Hydrograph reconstruction is done using rainfall and river inflow data as model input and enables definition at each time step of the ratio of each component. Using chemical data, representing event and pre‐event water, as input, it is possible to determine the origin of spring water (either fast flow through the epikarstic zone or slow flow through the saturated zone). This study made it possible to improve a conceptual model of allogenic karst system functioning. The methodology is used to study the Bas‐Agly and the Cent Font karst systems, two allogenic karst systems in Southern France.
Support networks of older people living in the community
Authors: Drennan Jonathan , Treacy Margaret P. , Butler Michelle , Byrne Anne , Fealy Gerard , Frazer Kate , Irving Kate 
Published: November 2008

Aim.  The aim of the study was to identify the social support networks of older people living in the community in Ireland using Wenger’s (1994) network typology.Background.  The population of older people in the community is increasing. With increasing age and changes in family circumstances a substantial proportion of older people will require social, psychological and instrumental support. However a lack of adequate social support networks for vulnerable older people can result in poor health, loneliness and isolation.Method.  A national, cross‐sectional telephone survey of 683 people aged between 65 and 99 years was undertaken using the Practitioner Assessment of Network Type as the basis for identifying social support networks.Results.  The results demonstrated that the majority of older people were living in stable and supportive social networks and reported high levels of contact with family, friends and neighbours. However, a significant minority of older people were living in vulnerable networks. Older people in these networks are susceptible to loneliness, isolation and poor emotional and physical health.Conclusion.  Through the identification of people in vulnerable networks, nurses working both in the hospital and community setting can ensure that formal support is aimed at providing care to older people who do not have access to informal care networks. Furthermore, the predictive utility of the Practitioner Assessment Network Type (PANT) can enable nurses to identify people at risk of poor social support.
Sampling Procedures for Coordinating Stratified Samples: Methods Based on Microstrata
Authors: Nedyalkova Desislava , Pea Johan , Tillé Yves 
Published: November 2008

SummaryThe aim of sampling coordination is to maximize or minimize the overlap between several samples drawn successively in a population that changes over time. Therefore, the selection of a new sample will depend on the samples previously drawn. In order to obtain a larger (or smaller) overlap of the samples than the one obtained by independent selection of samples, a dependence between the samples must be introduced. This dependence will emphasize (or limit) the number of common units in the selected samples. Several methods for coordinating stratified samples, such as the Kish & Scott method, the Cotton & Hesse method, and the Rivière method, have already been developed. Using simulations, we compare the optimality of these methods and their quality of coordination. We present six new methods based on permanent random numbers (PRNs) and microstrata. These new methods have the advantage of allowing us to choose between positive or negative coordination with each of the previous samples. Simulations are run to test the validity of each of them.
Tetranucleotide microsatellite loci from the black bear (Ursus americanus)
Authors: SANDERLIN JAMIE SKVARLA , FAIRCLOTH BRANT C. , SHAMBLIN BRIAN , CONROY MICHAEL J. 
Published: November 2008

AbstractWe describe primers and polymerase chain reaction conditions to amplify 21 tetranucleotide microsatellite DNA loci in black bears (Ursus americanus). We tested primers using individuals from two populations, one each in Georgia and Florida. Among individuals from Georgia (n = 29), primer pairs yielded an average of 2.9 alleles (range, one to four) and an average observed heterozygosity (HO) of 0.50 (range, 0.00 to 0.79). Among individuals from Florida (n = 19), primer pairs yielded an average of 5.7 alleles (range, one to 14) and an HO of 0.55 (range, 0.00 to 1.00). A comparison of previously developed markers with individuals from Georgia suggests that bear populations in Georgia and Florida have reduced allelic diversity relative to other populations.