bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retentive properties of three post‐core systems
Authors: Keyf Filiz , Şahin Erdal 
Published: May 2009

AbstractThe retention in root canals of Flexi‐Posts, Para‐Posts and Brasseler/Vlock‐Posts was measured using tensile and compressive/shear forces. Forty‐two extracted maxillary anterior teeth were embedded in self‐curing acrylic resin and treated endodontically. Each root canal was prepared with the appropriate matching drills for the post‐core system chosen. Each post‐core was cemented in the canal with zinc phosphate cement. A tensile force was applied along the long axis of each tooth and the force needed to dislodge the post‐core was recorded. There was no difference in retention between the small diameter posts, but the difference between the medium and the large diameter posts, however, was significant. In the medium diameter post group, the Flexi‐Post was approximately twice as retentive as the other two post‐core systems evaluated. In the second series of tests compressive/shear force was applied at an angle of 130 degrees to the long axis of the tooth. The retention difference between the small diameter posts was found to be statistically significant, Flexi‐Posts being more retentive than Para‐Posts and B/V‐Posts.
A comparative histological study of non‐porous and micro‐porous (algae‐derived) hydroxylapatite ceramics
Authors: Günhan Ömer , Bal Erol , Celasun Bülent , Şengün Onur , Finci Rifki 
Published: May 2009

AbstractTwo different types of hydroxylapatite ceramics were examined histologically to assess their effects on the healing of standardized bone defects drilled in the mandibular bone of beagles. After 40 days both materials were totally enclosed by newly‐formed bone, but only the defects filled with micro‐porous hydroxylapatite were found to show bone incorporation which is a good indicator of implant stability. These results suggest that the physio‐chemical similarities between the micro‐porous hydroxylapatite and native bone may promote effective bone incorporation which can increase the stability of implants.
Laser applications in dentistry: A review of the literature
Authors: Cernavin Igor , Pugatschew Anthony , de Boer Niels , Tyas Martin J. 
Published: May 2009

AbstractWhile there are many applications of lasers in dentistry, few have advantages over existing technology. To date, lasers should be considered to be an adjunct to conventional techniques. There are also considerations of cost and rapid obsolescence of current laser equipment. The possible adverse effects of lasers on the tissues adjacent to those being irradiated, to users and to patients must also be considered.
An investigation of discomfort experienced by dental therapists and assistants at work
Authors: Visser Jodie L. , Straker Leon M. 
Published: May 2009

AbstractDental therapists and assistants frequently experience musculoskeletal complaints associated with their work. In order to plan and implement programmes aimed at reducing the number of these complaints, the level and location of physical discomfort experienced by dental workers at work was documented to identify potential problem areas associated with dental practice.
Hygienist employment and the presence of periodontal notations in general dental practice patient records
Authors: Brown Louise F. , Keily Pamela A. , Spencer A. John 
Published: May 2009

AbstractAvailable data suggest that the provision of periodontal ly related services in general dental practices is low. However, studies indicate that the employment of dental hygienists is associated with increased provision. One method of measuring is by examination of notations in patient treatment records. As part of a project assessing the effectiveness of professional education in changing the provision of periodontal services, 2280 records, comprising 60 randomly selected records of dentate adult patients who had received a dental examination in the previous 6 months were audited in each of 38 practices, 13 of which employed hygienists. Entries of a periodontal nature were classified under 3 categories: diagnostic, preventive and treatment. The presence or absence of each item on each record was recorded. Diagnostic services were notated infrequently overall, but practices employing hygienists had a significantly lower number of records with no diagnostic notations. Preventive items were more frequently notated in practices employing hygienists. Treatment items were most frequently notated in both types of practices. Overall, 13 of the 23 items were recorded significantly more frequently in practices employing hygienists.
Some problems of dental treatment. Part 2. Treatment avoidance: Some differences between regular and irregular patients
Authors: Smyth John S. 
Published: May 2009

AbstractAnalysis of questionnaire data obtained from 54 irregular patients and 56 regular patients attending the Dental Department of the Lower Hutt Hospital and private practices in Lower Hutt and Wellington, New Zealand indicates that irregular patients are more anxious about dental treatment, value natural teeth less and find dental treatment more unpleasant than do regular patients. These and other survey findings on dental service utilization and dental anxiety suggest that the dental profession has a good deal of control over the way the public utilizes dental services. Most international surveys have found that less than 60 per cent of the population visits the dentist regularly, so there appears to be the potential for a substantial increase in regular use of dental services by the public. But, it is also likely that the longer an individual is remiss in regular dental care and the more teeth are lost, the more difficult conversion to regular visits will be.
An infected mandibular fracture. Case report
Authors: Thurnwald G. A. , Macleod A. W. Gordon 
Published: May 2009

AbstractA case of an infected mandibular fracture is presented. A submandibular abscess appeared to arise from chronic pericoronal infection associated with a third molar tooth in the line of fracture. Treatment of the case is described followed by a short discussion on the aetiology and management of infected mandibular fractures. The importance of adequate first aid and prompt referral is stressed.
Shear bond strength of a resin composite to enamel etched with maleic or phosphoric acid
Authors: Hallett Kerrod B. , Garcia‐Godoy Franklin , Trotter Amanda R. 
Published: May 2009

AbstractThe purpose of this study was to evaluate the effect of 10 per cent maleic and 37 per cent phosphoric acid on the shear bond strength of Z100 composite resin with Scotchbond Multi‐Purpose adhesive to primary and permanent tooth enamel. Four groups of 20 teeth each were established: 1, permanent teeth, 10 percent maleic acid etched for 15 seconds; 2, permanent teeth, 10 per cent maleic acid etched for 30 seconds; 3, permanent teeth, 37 per cent phosphoric acid etched for 15 seconds; 4, primary teeth, 10 per cent maleic acid etched for 15 seconds. Five teeth from each group were randomly assigned for SEM examination of the etched enamel surface. Scotchbond Multi‐Purpose primer and adhesive were applied to the etched enamel surface of the remaining 15 teeth and cured following the manufacturer's instructions. Z100 composite resin was placed in a nylon cylinder and cured for two 40 second intervals. Following thermocycling, the specimens were sheared on an universal testing machine and debonded areas were examined visually with a stereo microscope and with SEM. The mean shear bond strengths in MPa were: 1,17.00; 2, 14.58; 3, 14.66; 4, 11.18. ANOVA and Student‐Newman‐Keuls analyses revealed no statistically significant difference among the groups. SEM examination showed the majority of specimens fractured at the adhesive‐resin interface.
Physiopathology of primary periodontitis associated with plaque. Microbial and host factors. A review. Part 2
Authors: Liébana J. , Castillo A. 
Published: May 2009

AbstractTo a considerable extent, host factors condition the initiation and progression of periodontitis. The integrity of the periodontal structures and the immune elements in the gingival fluid may act as a defensive barrier against microorganisms. However, immune over‐response may lead to tissue damage and bone resorption from anaphylactic reactions, immunocomplex reactions, type IV hypersensitivity, complement hyperactivation via the alternative pathway, or direct action of leukocytes and macrophages. Moreover, insufficient host response allows bacteria to escape control, allowing more rapid progression of the disease.
Attitudes and smoking habits of dentists in Victoria: 16 years on
Authors: Mullins Robyn 
Published: May 2009

AbstractIn 1977 a survey of Victorian dentists measured their smoking prevalence, and their attitudes to dealing with patients who smoked. In 1993 these questions were repeated as part of a telephone survey of Victorian dentists. From 1977 to 1993 their prevalence of daily smoking had dropped from 30 per cent to 6 per cent, and this was not attributable simply to an influx of younger dentists who had never smoked. Many of those who had graduated in 1977 or more recently had never smoked, but many of the earlier graduates had quit, and there was no difference in the current smoking prevalence of the two groups. There had also been a change in dentists' attitudes towards smoking patients, with more of the 1993 sample (55 per cent) than the 1977 sample (43 per cent) agreeing with the statement ‘I encourage all my patients to give up smoking wherever possible’. Again, the more experienced dentists were adopting the new behaviours, not just the more recent graduates. Even so, in 1993 nearly half the dentists waited until the patient either was affected by smoking, or asked for advice before raising the issue.
The prognosis of oral mucosal squamous cell carcinomas: A comparison of clinical and histopathological grading and of laminin and type IV collagen staining
Authors: Firth Norman A. , Reade Peter C. 
Published: May 2009

AbstractChanges in the distribution of basement membrane components have been described in dysplastic lesions and in oral mucosal squamous cell carcinomas (OMSCC). The purpose of this study was to determine if these changes were related to pathological grade and if so, whether this had prognostic implications. Fifty formalin‐fixed, paraffin‐embedded specimens of OMSCC, with five or more years clinical follow‐up, were studied using an immunoperoxidase technique for the detection of the basement membrane components, laminin and type IV collagen. The immunoreactivity of each component was evaluated and semiquantitatively scored as minimal, moderate or extensive and the results compared with the tumour size, node involvement and metastasis (TNM) clinical staging system and histopathological features. OMSCC were characterized by minimal or moderate staining with small islands of neoplastic cells frequently lacking staining for laminin and type IV collagen. Deposition of these components decreased with increased histopathological grade and absence of staining was more commonly associated with a poor prognosis. In particular the pattern of type IV collagen staining frequently differed from laminin staining. Neither of these parameters offered an advantage over TNM clinical staging with regard to prognosis. It was concluded that variations in laminin and type IV collagen immunoreactivity occured in OMSCC and that high histopathological grade tumours with considerably diminished staining with anti‐laminin and anti‐type IV collagen carried a poor prognosis.
Identification and classification of species within the Streptococcus sanguis group
Authors: Willcox M. D. P. 
Published: May 2009

AbstractA biochemical identification scheme has been produced that allows for the differentiation of nine distinct species within the Streptococcus sanguis group. The species are S. sanguis, S. gordonii, S. crista, S. oralis, S. parasanguis, S. defectivus, S. adjacens and S. mitis, which have been previously described, and a new species, S. australis; In addition two distinct subspecies, S. oralis subsp. corona and S. oralis subsp. mitior, have been identified. DNA‐DNA hybridization confirmed the separation of strains Into the species. A new type of peptidoglycan peptide linkage, lys‐ala‐gly was also found within this species S. parasanguis and S. australis that has not been observed within the streptococci previously. DNA fingerprinting was shown to be a useful method for discriminating between strains within species, but did not allow discrimination between species.
The strength of auto‐cured and light‐cured materials. The shear punch test
Authors: Mount G. J. , Makinson O. F. , Peters M. C. R. B. 
Published: May 2009

AbstractThis paper examines the versatility of the shear punch test as described by Roydhouse and suggests that it should be considered as an alternative to the present standard compressive strength test for glass ionomer cements and flexural strength for composite resins. The shear punch test can be used for examining small thin specimens, about 1.0 mm thick and 8.0 mm in diameter, of both auto‐cured and light‐cured restorative materials such as composite resins and glass ionomer cements. The preparation of the specimen is simple and does not require a precision mould or subsequent machining to size except that, after curing, it may need to be abraded gently to obtain flat parallel test surfaces. The test apparatus consists of a punch approximately 3.0 mm in diameter opposing a true fitting matching die. The specimen is supported over the die section and the punch is advanced through it in a compression cage. The formula used to calculate the shear strength allows for variation in specimen thickness and thus provides comparative data between materials. It also allows examination of the effects of variations in manipulation, maturation and storage of each material. It is suggested this test should be considered as an alternative to the present compression and flexural strength tests because it would provide a single strength test for a range of restorative materials being manipulated under a variety of circumstances. It is of particular significance for testing the light‐cured materials because it examines a specimen size below that of the diameter of the exit window of a normal clinical light curing unit and also at a thickness where depth of cure of the material is not a problem.
An African Success Story: Ghana's Cocoa Marketing System
Authors: Williams Tracy 
Published: May 2009

SummaryGhana's cocoa marketing system has performed impressively over the past decade. Cocoa production has reached record high levels. Farmers receive a relatively large share of export earnings. Product quality is world renowned, and it regularly exceeds the most stringent international standards. Exports are handled professionally and efficiently. International loans are repaid reliably. Internal marketing is relatively uncorrupt and effective. This is a home‐grown success story, under the stewardship of a state‐run marketing board – the Cocobod – which manages almost all aspects of the internal cocoa marketing process and maintains a monopoly on cocoa exports. Given the dismal history of African commodity marketing boards in general, and of Ghana's cocoa marketing board in particular, this success demands explanation. It was not the result of radical transformation but of relatively subtle changes in the system that maintained the undoubted benefits of a centralised monopoly while minimising its damaging consequences. Success resulted from (1) building on the underlying strength of certain elements in the system, notably quality control and export management, (2) an episode of well‐directed reform, and (3) effective policies and organisational structures that protected the farmers' share of the cocoa revenues over time and inhibited the Cocobod returned to the politicisation it suffered in the past. The case accords with the much‐touted but oft‐neglected lesson that both context and institutions matter for organisational performance. In particular, complementary contexts and institutions can produce valuable synergies. More substantively, it suggests that poorly performing organisations in Africa may be turned around without radical measures.
Educating the Citizen Engineer: Making a Case for Community Service in Engineering
Authors: Fleischmann Shirley T. 
Published: May 2009

The first two fundamental principles in the ASME Code of Ethics are that” engineers uphold and advance the integrity, honor and dignity of the engineering profession by: I. Using their knowledge and skill for the advancement of human welfare; II. Being honest and impartial, and serving with fidelity the public, their employers and clients…” These principles involve the concept of “the public good” and are properly part of engineering ethics — yet it is difficult to find a good place in the curriculum to address these principles. This paper will present the idea of using community service in engineering as a context for teaching this aspect of engineering ethics. The author has considerable experience in community service projects — related to engineering courses in which project work is required and graded, and also related to projects that involve purely voluntary efforts. Specific examples of projects that have been used will be given. The projects have also been presented as part of the larger Honor Concept that the author has been instrumental in developing for the School of Engineering at Grand Valley State University. “The habit of apprehending a technology in its completeness: this is the essence of technological humanism, and this is what we should expect education in higher technology to achieve. I believe it could be achieved by making specialist studies the core around which are grouped liberal studies which are relevant to those specialist studies. But they must be relevant; the path to culture should be through a man’s specialism, not by-passing it…A student who can weave his technology into the fabric of society can claim to have a liberal education; a student who cannot weave his technology into the fabric of society cannot claim even to be a good technologist.” Lord Ashby, Technology and the Academics
Underground gas storage: An introduction and UK perspective
Authors: Evans D. J. , Chadwick R. A. 
Published: May 2009

Abstract

Rising demand and the depletion of its offshore reserves has resulted in the UK becoming a net importer of natural gas. An increased reliance on imports and limited current storage availability mean that the UK faces increasing energy bills and risk of disruption to supply. Because of this the UK government has set about ensuring security of energy supply. Steps taken include the construction of major new pipelines from Norway and Holland and improvements to interconnectors in the southern North Sea. The Government also recognizes that improvements to the gas supply infrastructure are required, including the need for significant increases in gas storage capacity; best met by the construction of underground storage facilities. Focus on energy security has also raised the likelihood of a new generation of coal-fired power-stations. For such a step to be environmentally viable, clean-coal technologies with near-zero greenhouse gas emissions will be required. Underground CO
2
storage will be a key element of this strategy. This volume reviews the technologies and issues involved in the underground storage of natural gas and CO
2
, by means of case-studies and examples from the UK and also from overseas. The potential for underground storage of other gases such as hydrogen, or compressed air linked to renewable sources is also reviewed.
Well integrity: An overlooked source of risk and liability for underground natural gas storage. Lessons learned from incidents in the USA
Authors: Miyazaki Brent 
Published: May 2009

Abstract
Safety is a primary concern at underground gas storage (UGS) sites. Thorough evaluation of all potential migration pathways is critical to ensure UGS containment and public safety. Substantial risk is directly associated with inaccurate technical evaluations, that may result in subsequent gas migration from a UGS facility.
Existing wellbores, including abandoned oil and gas wells, old dry exploration wells and water wells represent primary potential vertical gas migration conduits, which are not always thoroughly analysed during UGS site evaluation studies. Most abandoned oil and gas wells develop leaks over time, even when plugged in accordance with current (US) government regulations.
Leaking wells in urban areas represent significant health and safety hazards. Many cities including Los Angeles permit construction of new homes directly over abandoned wells, even though state agencies recommend against this practice, thus placing residents at risk. Explosions and fires, along with possible exposure to substances such as benzene and toluene, are possible when gas reaches the surface through leaking wells and accumulates inside building voids. These potential problems are amplified with UGS fields, where operating pressures, already raised above the declining pressures of the field, fluctuate when alternating gas injection and extraction induce cyclic stress on wellbores and caprock sequences.
Review of monitoring issues and technologies associated with the long-term underground storage of carbon dioxide
Authors: Chadwick R. A. , Arts R. , Bentham M. , Eiken O. , Holloway S. , Kirby G. A. , Pearce J. M. , Williamson J. P. , Zweigel P. 
Published: May 2009

Abstract

Large-scale underground storage of CO
2
has the potential to play a key role in reducing global greenhouse gas emissions. Typical underground storage reservoirs would lie at depths of 1000 m or more and contain tens or even hundreds of millions of tonnes of CO
2
. A likely regulatory requirement is that storage sites would have to be monitored both to prove their efficacy in emissions reduction and to ensure site safety. A diverse portfolio of potential monitoring tools is available, some tried and tested in the oil industry, others as yet unproven. Shallow-focused techniques are likely to be deployed to demonstrate short-term site performance and, in the longer term, to ensure early warning of potential surface leakage. Deeper focused methods, notably time-lapse seismic, will be used to track CO
2
migration in the subsurface, to assess reservoir performance and to calibrate/validate site performance simulation models. The duration of a monitoring programme is likely to be highly site specific, but conformance between predicted and observed site performance may form an acceptable basis for site closure.