bluuebunny/crossref_metadata_2025 huggingface dataset:
The comprehensive evaluation of temporomandibular disorders seen in rheumatoid arthritis
Authors: Ardic F. , Gokharman D. , Atsu S. , Guner S. , Yilmaz M. , Yorgancioglu R.
Published: March 2008

Background: We studied clinical signs and symptoms of temporomandibular disorders and radiological changes in the temporomandibular joint from patients with rheumatoid arthritis (RA) compared to patients with myofascial pain dysfunction of the temporomandibular system and control patients to evaluate clinical and radiological relationships.

Methods: A cross‐sectional, controlled, clinical and radiological study was planned and 99 subjects (69 patients and 30 controls) were included in the study.

Results: Twenty‐three patients with RA (69.7 per cent) had painful temporomandibular joint. Fifty‐five per cent had myofascial pain dysfunction according to the research diagnostic criteria for temporomandibular disorders (TMD). Nearly all of our patients with RA (93.9 per cent) had symptoms, and almost all of them had positive findings of TMD in high resolution computed tomography. Condylar head resorption, joint space narrowing and degeneration were statistically more prominent features in patients with rheumatoid arthritis compared with controls (p<0.05). The pain score on active palpation correlated with the number of the mandibular subchondral cysts on high resolution computed tomography (r=0.6, p<0.05).

Conclusion: Although the myofascial pain of the temporomandibular system is an important cause of pain in rheumatoid arthritis, prospective controlled studies are needed to develop effective therapeutic strategies for these patients.
Flexural properties of glass fibre reinforced acrylic resin polymers
Authors: Tacir IH , Kama JD , Zortuk M. , Eskimez S.
Published: March 2008

Background: In recent years, glass fibres have been used to strengthen denture base resins. A major difficulty in using reinforcing fibres with multiphase acrylic resins, such as powder liquid resins, is inadequate impregnation of the fibres with the resin.

Methods: This investigation examined the reinforcing effect of glass fibres on the fracture resistance and flexural strength of acrylic denture base resins. Eighty identical specimens were formed in specially designed moulds in accordance with the manufacturer's recommendations. The four experimental groups were prepared and these consisted of conventional acrylic resin and the same resin reinforced with glass fibres. Ten specimens were fabricated in a standardized fashion for each experimental group. Flexural strength was tested using a 3‐point universal testing machine.

Results: In this study, statistically significant differences were found in the flexural strength of the specimens (P<0.05). The injection‐moulded, fibre‐reinforced group had significantly lower flexural strength than the injection‐moulded group (P<0.001), and the microwave‐moulded, fibre‐reinforced group had lower flexural strength than the microwave‐moulded group. The fracture resistance was significantly higher in the injection‐moulded, fibre‐reinforced group than in the injection‐moulded group (P<0.05), and the fracture resistance was significantly higher in the microwave‐moulded, fibre‐reinforced group than in the microwave‐moulded group.

Conclusion: Within the limitations of this study, the flexural strength of heat‐polymerized PMMA denture resin was improved after reinforcement with glass fibres. It may be possible to apply these results to distal extension partial and complete denture bases.
The ability of thiourea to scavenge hydrogen peroxide and hydroxyl radicals during the intra‐coronal bleaching of bloodstained root‐filled teeth
Authors: Farmer DS , Burcham P. , Marin PD
Published: March 2008

Background
: Hydrogen peroxide, an agent used in the intra‐coronal bleaching of root‐filled teeth for over a century, has been shown to diffuse from the pulp chamber to the outer root surface. Furthermore, it has been demonstrated that destructive hydroxyl radicals, the by‐products of the bleaching process, have been detected on the external root surface. The control of such diffusion may be of importance in minimizing the risk of invasive cervical resorption (ICR) which has been linked to intra‐coronal bleaching of discoloured root‐filled teeth using hydrogen peroxide. The aims of the present in vitro study are to quantify the diffusion of hydrogen peroxide and hydroxyl radicals to the outer root surface following intra‐coronal bleaching, and to evaluate the ability of thiourea incorporated into the bleaching protocol to scavenge residual hydrogen peroxide and hydroxyl radicals.

Methods
: Thirty‐five single rooted premolar teeth with intact cementum at the cemento‐enamel junction were used in this project. Thirty teeth were stained with red blood cells and root‐filled with gutta‐percha and AH26. The five unstained teeth were root‐filled and constituted a negative control (Group 1). The stained teeth were divided equally into the following experimental groups and subjected to various intra‐coronal bleaching regimes: Group 2–‘walking bleach’ with 20μl 30 per cent w/w hydrogen peroxide; Group 3–20μl 30 per cent w/w hydrogen peroxide and thermocatalytically activated; Group 4–20μl acidified thiourea; Group 5–20μl acidified thiourea and 20μl 30 per cent w/w hydrogen peroxide; Group 6 –20μl acidified thiourea and 20μl one per cent sodium hypochlorite; Group 7 –20μl acidified thiourea, 20μl one per cent sodium hypochlorite and 20μl 30 per cent w/w hydrogen peroxide. The reaction products of the bleaching process were quantified at the outer root surface using high performance liquid chromatography and electrochemical detection (HPLC‐ECD).

Results
: Results showed that hydrogen peroxide used alone in Groups 2 and 3 was able to be detected at the outer root surface in 100 per cent of the samples, and that the presence of the hydroxyl radical generated in both groups was detected in equal amounts (P < 0.05). When thiourea was incorporated into the bleaching protocols in Groups 5–7, it was shown to scavenge both hydrogen peroxide and hydroxyl radicals to a significant degree (P < 0.05).

Conclusions
: Acidulated thiourea is an effective scavenger of residual hydrogen peroxide and hydroxyl radicals generated during the intra‐coronal bleaching of bloodstained root‐filled teeth.
Prevalence of percutaneous exposure incidents amongst dentists in Queensland
Authors: Leggat PA , Smith DR
Published: March 2008

Background
: Percutaneous exposure incidents (PEI) represent an important occupational health issue in dentistry, and one that can incur severe consequences from blood‐borne infections. Given the importance of this topic, we considered it necessary to investigate the distribution and cause of PEI among Queensland dentists.

Methods
: In 2004, a self‐reporting questionnaire was mailed to a random sample of 400 dentists on the register of the Queensland Branch of the Australian Dental Association.

Results
: A total of 285 questionnaires (73.1 per cent) were completed and returned. Of the respondents, 73.3 per cent were male and 26.7 per cent female, with a mean age of 45.2 years (SD = 11.9 years). Most were general dentists (89.1 per cent) with the remainder being specialists (10.9 per cent). More than three‐quarters (78.5 per cent) reported damaging their gloves at least once during a clinical procedure in the previous 12‐month period. Roughly one‐quarter (27.7 per cent) had experienced at least one ‘sharps’ or needlestick injury in the previous 12 months, 16.1 per cent of which involved a contaminated instrument that had been previously used on a patient. The most common devices to cause ‘sharps’ injury in the previous 12 months were needles (14.4 per cent) and burs (10.2 per cent).

Conclusions
: Although PEI clearly remains a major occupational health problem for Queensland dentists, the prevalence of needlestick injuries appears to be lower than other studies from developed countries. The identification of needle‐stick injuries as a common cause of PEI again stresses the importance of preventive strategies with respect to potential blood‐borne infections. Further research is now needed to more carefully identify effective measures for reducing PEI among dental personnel.
Bond strengths between composite resin and auto cure glass ionomer cement using the co‐cure technique
Authors: Knight GM , McIntyre JM , Mulyani
Published: March 2008

Background
: The clinical technique for sandwich restorations prescribes etching initially set auto cure glass ionomer cement (GIC) prior to placing a layer of resin bond to develop a weak mechanical bond between composite resin and GIC. Co‐curing a resin modified glass ionomer cement (RMGIC) bond and composite resin to GIC may create a chemical bond and improve the bond strengths between these two materials.

Methods
: A total of 48 specimens were prepared, 12 in each of four categories. Capsulated GIC was placed into a mould and allowed to set for four minutes, etched for five seconds followed by placement of a resin bond and photo cured for five seconds over which a composite resin was puddled onto the resin bond and photo cured for 10 seconds. Capsulated GIC was placed into a mould and allowed to set for four minutes after which a sample of RMGIC (Riva LC) was prepared using twice the liquid powder ratio and painted over the surface of the set GIC using a micro brush. An increment of composite resin was added over the RMGIC and both materials were photo co‐cured for 10 seconds. Capsulated GIC was placed into a mould and RMGIC (Riva LC) that had been prepared using twice the liquid powder was brushed over the GIC (prior to initial set) followed by the placement of a layer of composite resin and photo co‐cured for 10 seconds. Capsulated GIC was placed into a mould and RMGIC (Fuji II LC) that had been prepared using twice the liquid powder was brushed over the GIC (prior to initial set) followed by the placement of a layer of composite resin and photo co‐cured for 10 seconds. Shear testing of each of the samples was carried out and specimens were examined to determine the nature of the fracture. Selected samples were prepared for SEM investigation to observe the interfaces between the GIC and composite resin.

Results
: There were significantly lower bond strengths (P < 0.05) amongst samples that had been etched and bonded (2.42MPa) compared to the other samples that had been co‐cure bonded with RMGIC (6.48–7.05MPa). There were no significant differences amongst the bond strengths of the samples co‐cure bonded with RMGIC. Specimens prepared by the ‘etch and bond’ technique failed adhesively and co‐cured specimens failed cohesively within the GIC. SEM investigation showed chemical bonds between RMGIC bond and GIC and composite resin.

Conclusions
: The co‐cured RMGIC bonding system eliminates several placement steps and produces a significantly stronger chemical bond between GIC and composite resin than the ‘etch and bond’ technique. RMGIC bond and composite resin may be co‐cured to GIC either before or after initial set has occurred.
The mandibular ramus donor site
Authors: Brener D.
Published: March 2008

With the increased awareness of the population about dental implants, more patients are presenting after losing a number of teeth and requesting fixed solutions to their dilemmas. Often they have lost width of alveolus which does not allow implant placement without its augmentation. The mandibular ramus is one intra‐oral site that can supply excellent quality and often quantity of autologous bone for use in augmenting alveolar ridge deficiencies. This article describes the general surgical principles in harvesting the mandibular ramus.
Ion uptake into demineralized dentine from glass ionomer cement following pretreatment with silver fluoride and potassium iodide
Authors: Knight GM , Mclntyre JM , Craig GG , Mulyani
Published: March 2008

Background: Diamine silver fluoride (Ag(NH3)2F), referred to as AgF, has been shown to provide a pronounced antimicrobial action against caries. The clinical application of this material has been limited by the staining associated with both teeth and tooth coloured restorative materials. The application of potassium iodide (KI) after AgF eliminates stain formation. The purpose of this study was to determine if a prior application of silver fluoride and potassium iodine to demineralized dentine affected the uptake of strontium and fluoride from a glass ionomer cement restoration.

Method: Three cavities were prepared in each of five recently extracted human third molars. The cavities were demineralized and treated as follows. In each tooth, one cavity was left as a control, one cavity was restored with glass ionomer cement and one cavity was treated with 1.8M AgF and a saturated KI solution and then restored with glass ionomer cement. The penetration of the various elements into demineralized dentine was measured by their relative percentage weights using electron probe microanalysis (EPMA).

Results: Fluoride uptake was significantly higher in the AgF and KI treated samples compared to the other two samples and significantly higher in the glass ionomer restored sample compared to the control. The application of AgF and KI did not significantly interfere with the transfer of strontium from glass ionomer cement into dentine. Silver and iodine deposits were present in the demineralized dentine treated with AgF and KI.

Conclusions: The application of AgF and KI onto dentine prior to the placement of glass ionomer cement did not significantly affect the strontium uptake into the subjacent demineralized dentine and the fluoride levels in this zone were significantly increased.
Clinical, radiographic and histological analysis of the effects of mineral trioxide aggregate used in direct pulp capping and pulpotomies of primary teeth
Authors: Caicedo R. , Abbott PV , Alongi DJ , Alarcon MY
Published: March 2008

Background: Primary teeth pulp exposures have traditionally been treated with formocresol or ferric sulphate pulpotomies or calcium hydroxide pulp capping. The aim of this study was to observe the tissue response when mineral trioxide aggregate (MTA) was used.

Methods: Ten primary teeth had direct pulp caps and 11 had a pulpotomy with MTA. The teeth were restored and then clinically reviewed monthly for five months and before extraction. Radiographs were taken prior to treatment, after one month and prior to extraction. After extraction, the teeth were examined histologically and the responses to treatment were assessed.

Results: One pulpotomy and two pulp capping cases had postoperative pain and signs of pulp degeneration. Radiographs showed no root resorption, no periodontal pockets and no furcation radiolucencies. No cases had draining sinuses or increased mobility. Most pulps responded favourably from a clinical perspective although a variety of responses were noted Histologicallyormal odontoblasts, irregular odontoblasts, intrapulpal calcifications, dentinal bridges, cementum formation, internal resorption, inflammatory infiltrate and pulp necrosis.

Conclusions: The responses of pulps in primary teeth to MTA pulpotomies and pulp caps were favourable from clinical and radiographic perspectives although a variety of histological responses were noted. MTA may be a favourable material for pulp capping and pulpotomies in primary teeth.
Problem‐based learning in dental education: what's the evidence for and against … and is it worth the effort?
Authors: Winning T. , Townsend G.
Published: March 2008

All Australian dental schools have introduced problem‐based learning (PBL) approaches to their programmes over the past decade, although the nature of the innovations has varied from school to school. Before one can ask whether PBL is better than the conventional style of education, one needs to consider three key issues. Firstly, we need to agree on what is meant by the term PBL; secondly, we need to decide what “better” means when comparing educational approaches; and thirdly, we must look carefully at how PBL is implemented in given situations. It is argued that PBL fulfils, at least in theory, some important principles relating to the development of new knowledge. It also represents a change in focus from teachers and teaching in conventional programmes to learners and learning. Generally, students enjoy PBL programmes more than conventional programmes and feel they are more nurturing. There is also some evidence of an improvement in clinical and diagnostic reasoning ability associated with PBL curricula. The main negative points raised about PBL are the costs involved and mixed reports of insufficient grounding of students in the basic sciences. Financial restraints will probably preclude the introduction of pure or fully integrated PBL programmes in Australian dental schools. However, our research and experience, as well as other published literature, indicate that well‐planned hybrid PBL programmes, with matching methods of assessment, can foster development of the types of knowledge, skills and attributes that oral health professionals will need in the future.
Comparative uptake of fluoride ion into enamel from various topical fluorides in vitro
Authors: Pai N. , McIntyre J. , Tadic N. , Laparidis C.
Published: March 2008

Background: There are many forms of topical fluoride available today, making the decision as to which is most effective to manage the immediate caries risk problem at hand, very difficult. The objective of this project was to determine the concentration and pattern of fluoride ion uptake into enamel from a variety of categories of topical fluoride recently available in Australia.

Methods: Extracted, intact molar teeth were sectioned to provide six plates of smooth surface enamel. Windows of enamel 2 times 6mm were exposed to a variety of topical fluorides for periods simulating those used in vivo. Following drying, the slates of enamel were exposed to 2ml of 0.1M HCl as a chemical biopsy agent for incremental periods of time. The concentrations of fluoride ion in the biopsy solutions for both test and background (control) slates of enamel were determined directly using a fluoride combination selective electrode in conjunction with a high impedance pH meter. Cumulative amounts of fluoride were determined for each topical fluoride agent.

Results: The concentrations of fluoride ion taken up into enamel were generally proportional to those present in each agent. However, those from APF gel greatly exceeded the amounts taken up from NaF gel. Also, the concentrations taken up from some of the highly concentrated metal fluorides were surprisingly low. Prior etching of enamel increased uptake and prolonged application of APF gel provided no extra benefit.

Conclusions: Some topical fluorides, e.g., APF gel, provided a greatly increased uptake and to a greater depth than other self‐application products. However, the frequency of its use should be considered with caution where patients have glass‐based restorations.
Different bone loading patterns due to fixation of three‐unit and five‐unit implant prostheses
Authors: Karl M. , Winter W. , Dickinson AJ , Wichmann MG , Heckmann SM
Published: March 2008

Background: It has been considered that implant prostheses ought to display passive fit. The objective of this finite element analysis (FEA) was to simulate the bone loading resulting from the fixation of implant‐supported three and five‐unit fixed partial dentures (FPDs).

Methods: Based on a patient case, six different FPD‐groups were fabricated using either two or three implants for support. Strain gauges on the pontics of the prostheses were used for in vivo measurements. Based on the values obtained, bone loading models were simulated using three‐dimensional finite element analysis and the results obtained were represented as von Mises equivalent stress.

Results: The mean strain (e) values ranged from 15μe to 170μe for the three‐unit FPDs and from 32μe to 302μe for the five‐unit FPDs. FEA revealed von Mises stresses up to 30MPa in the cortical area, while in trabecular bone values up to 5MPa were observed. Static implant loading of similar magnitude can be provoked through 200N axial load.

Conclusions: Although the in vivo measured strain levels (e) were of higher magnitude for the five‐unit prostheses, FEA revealed bone loading of comparable magnitude for both three‐and five‐unit FPDs. Multi‐unit prostheses may demonstrate greater inaccuracies compared with single implant restorations, but due to the absence of moment loading the multi‐implant configuration appears to compensate for the higher strain development.
Laser‐activated fluoride treatment of enamel as prevention against erosion
Authors: Vlacic J. , Meyers IA , Walsh LJ
Published: March 2008

Background: Erosion is the loss of dental hard tissues from an acidic challenge, often resulting in exposure of dentinal tubules and hypersensitivity to environmental stimuli. Laser‐activated fluoride (LAF) therapy with 488nm laser energy has been shown previously to increase the resistance of human enamel and dentine to acid dissolution. The aims of this study were to investigate the action spectrum of LAF in protecting tooth enamel from softening in response to an erosive challenge, and to examine for any temperature change with the treatment.

Materials and Methods: Buccal and lingual surfaces of extracted sound molar and premolar teeth were used to prepare matched pairs of enamel slabs (N=10 per group). After application of 1.23% neutral sodium fluoride gel (12 300ppm F ion), slab surfaces were lased with 488, 514.5, 532, 633, 670, 830 or 1064nm wavelength (energy density 15J/cm2; spot size 5mm), then exposed to an erosive challenge (1.0M HCl for five minutes). The Vicker's hardness number (VHN) was recorded before fluoride gel application and again following the acid challenge. Negative controls did not receive laser exposure.

Results: All wavelengths of laser light examined provided a protective LAF effect against softening, compared with the negative control surfaces.

Conclusion: From these findings, we conclude that the action spectrum of the LAF effect extends across the visible spectrum, providing protection to dental enamel from an erosive challenge.
An in vitro investigation of marginal dentine caries abutting composite resin and glass ionomer cement restorations
Authors: Knight GM , McIntyre JM , Craig GG , Mulyani  , Zilm PS , Gully NJ
Published: March 2008

Background: There are a number of studies citing the primary reason for replacing auto cure glass ionomer cements was due to recurrent caries. The purpose of this study was to use an in vitro model to measure caries at the dentine restoration interface of bonded composite resin and auto cure glass ionomer cement restorations and to measure the amount of surface degradation occurring in the restorative materials.

Methods: Specimens of auto cure glass ionomer cements (Riva Fast, Fuji IX Fast, Ketac Molar Quick and Fuji VII) and bonded composite resin restorations (Ice, SDI) were placed separately at the dentino‐enamel junction of 10 recently extracted human third molar teeth, disinfected and placed into the overflow from a continuous culture of S. mutans for two weeks. Restorations were sectioned and prepared for scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Restoration tooth interfaces were photographed and the distance from the surface of the teeth to the surface of the restorations measured. EPMA of percentage weights of calcium, phosphorous and fluoride were made outwards from the restoration surface 130μm at a depth of 10μm below the surface of the dentine.

Results: There were significant differences between the surface heights of composite resin, auto cure glass ionomer cements compared to teeth surfaces. Percentage weights of calcium and phosphorus levels were similar to non‐demineralized dentine in the auto cure glass ionomer cement samples but there were significant reductions in mineral content of dentine adjacent to bonded composite resin restorations. Fluoride levels were mixed.

Conclusions: This study shows that placing a bonded composite resin restoration into dentine affords little protection to the surrounding tooth from caries attack although insignificant degradation of the restorative surface occurs. Placing a glass ionomer cement restoration into dentine protects the surrounding tooth from caries but degradation of the restoration surface occurs.
An in vitro evaluation of the accuracy of Dentaport ZX apex locator in enlarged root canals
Authors: Ebrahim AK , Wadachi R. , Suda H.
Published: March 2008

Background: The aim of this study was to examine the effects of root canal irrigants on the accuracy of Dentaport ZX™® electronic apex locator (EAL) in enlarged root canals. Our previous study revealed that as the diameter of the root canal increased, the electronically measured length with small size files became shorter in the presence of blood. It is not known whether different canal irrigants would interfere with the reading accuracy of an EAL in enlarged root canals.

Methods: A total of 45 extracted single‐rooted human teeth were used. In Stage 1, canals were instrumented using #10–40 K‐files with a #40 K‐file as the master apical file (MAF). The teeth were randomly divided into five groups and mounted in an experimental apparatus. The following irrigants were used during electronic canal measurements: Group A = 0.5% NaOCl; Group B = 2.5% NaOCl; Group C = 15% EDTA; Group D = 0.8% chlorhexidine (CHX); and Group E = RC Prep. In Stage 2, the canals were enlarged using a #60 K‐file as the MAF. In Stages 1 and 2, the apical portion of the canals was instrumented using the step‐back sequence (up to a #80 K‐file). In Stage 3, the canals were enlarged again using a #80 K‐file as the MAF. In each stage, the canal length was measured with a Dentaport ZX™® using #10 and #40, #10 and #60, and #10 and #80 K‐files for Stages 1, 2 and 3, respectively. Data were analysed by two‐way ANOVA and Fisher's PLSD test.

Results: Statistical analysis showed significant differences among all groups (p < 0.01). There was no significant difference between Group A and B at each stage and between Group D and E at Stage 2. A statistical significant difference was observed between #10 K‐file and other files (#40, #60 and #80) at each stage (p < 0.01). In Groups A and B, there was no significant difference between #10 and 40 K‐files (Stage 1) and between #10 and #60 K‐ files (Stage 2).

Conclusion: The Dentaport ZX™® was accurate and not adversely affected by the presence of 0.5% or 2.5% NaOCl and EDTA in the enlarged canals, and the measured lengths obtained with small and large size files were comparable. However, it was accurate in the presence of CHX and RC Prep only when large size files were used, and the length measured with small size files was greater than the actual length.
Attachment of periodontal fibroblasts to barrier membranes coated with platelet‐rich plasma
Authors: Chang T. , Liu Q. , Marino V. , Bartold PM
Published: March 2008

Background: This study evaluated the attachment of human periodontal ligament (HPDL) and human gingival (HG) fibroblasts onto commercially available barrier membranes coated with plateletrich plasma (PRP).

Methods: Gore‐Tex® Regenerative Membrane (GTN1), Inion GTR® Biodegradable system (INION), and Gore‐Resolut XT Regenerative membrane (GTRX) were studied. The membranes were pre‐wetted with phosphate buffered saline before exposure to PRP for two hours. HPDL or gingival fibroblasts were then seeded onto the membranes and incubated in culture medium for 24 hours. The samples were then fixed and processed for light and scanning electron microscopy evaluation.

Results: PRP‐coated membranes showed greater cell attachment compared to non‐coated membranes. The INION membrane showed the greatest attachment followed by the GTN1 and GTRX membranes. The cells showed increased cytoplasmic extensions and appeared more intertwined around individual fibres of the membranes compared to uncoated control membranes.

Conclusion: HPDL and HG fibroblasts have a distinct reaction with different membranes depending on both microstructure and composition of the membrane. Coating membranes with PRP had a significant impact on the way HPDL and HG fibroblasts attach to certain barrier membranes by increasing both the amount and the quality of attachment.
Factors involved in the translation of continuing professional development programmes into clinical practice among Victorian dentists
Authors: John V. , Parashos P.
Published: March 2008

Background: Continuing professional development (CPD) programmes have traditionally been seen as an important means by which dentists keep up‐to‐date with current advances in the field. Recent legislative changes in Victoria have resulted in the introduction of mandatory CPD for dentists. Despite this, there is limited available information on the effectiveness of the translation of these programmes into clinical practice.

Methods: Participants undertaking CPD programmes in endodontics and implant dentistry were surveyed using three questionnaires over three time‐frames: pre‐CPD, post‐CPD and three months following the programme (delayed). The course format of the programmes involved both didactic lecture and interactive hands‐on components.

Results: Overall response rates of 94 per cent for pre‐CPD and post‐CPD questionnaires, and 77 per cent for the delayed impact‐on‐practice questionnaire were achieved. Programmes in both disciplines were found to be effective in facilitating the uptake of the new technologies taught in the courses. The time‐series design of the present survey was effective in identifying dentists' background knowledge, experiences and biases, and in evaluating the translation of CPD programmes into clinical practice.

Conclusions: A variety of discipline‐related and participant‐related factors were identified which may influence the uptake of learned concepts and techniques by participants undertaking CPD programmes. Educators must be cognizant of these issues to ensure that these programmes positively impact on clinical practice, in particular the adoption of technological advances or technical aspects and relating it to the biological goals of treatment, thus facilitating an overall improvement in health care outcomes.
Bacteria and salivary profile of adolescents with and without cleft lip and/or palate undergoing orthodontic treatment
Authors: Cheng LL , Moor SL , Kravchuk O. , Meyers IA , Ho CTC
Published: March 2008

Background: Patients with cleft lip and/or palate (CL&/P) experience a higher caries prevalence. This study aimed to determine if patients with CL&/P, undergoing and not undergoing orthodontic treatment, have a different salivary biochemical profile and different salivary levels of Mutans Streptococci (MS) and Lactobacilli (LB) compared to patients undergoing and not undergoing orthodontic treatment without CL&/P.

Methods: One hundred and ten subjects aged between 12 and 17 years were recruited into one of four different groups comprising two control groups and two treatment groups. The control groups comprised of subjects with and without CL&/P who were not undergoing orthodontic treatment. The treatment groups comprised of subjects with and without CL&/P undergoing orthodontic treatment. Regular reinforcement of oral hygiene instructions, dietary counselling and debridement, when necessary, were offered to subjects in the treatment groups following their orthodontic adjustment appointments. The salivary secretion time, pH of resting and stimulated saliva, salivary flow rate, buffering capacity, quantity of salivary MS and LB were measured.

Results: Subjects with CL&/P undergoing orthodontic treatment at the Children's Oral Health Service tended to present with microbiological and salivary profiles that were less favourable for caries development. There was a significant difference in the percentage of subjects with >105 colony forming units (CFU)/mL of MS between the cleft treatment and non‐cleft treatment groups. Subjects in the non‐cleft treatment group had the highest percentage of subjects (86.7 per cent) with >105 CFU/mL of MS whereas subjects in the cleft treatment group had the lowest percentage of subjects (60 per cent) with >105 CFU/mL of MS. For LB, there were significantly higher percentages of subjects with >105 CFU/mL of LB in the non‐cleft treatment (76.7 per cent) and cleft treatment (73.3 per cent) groups compared to the non‐cleft control (46.7 per cent) and cleft control (40.0 per cent) groups.

Conclusions: Regular oral hygiene reinforcement and dental health education appears to have a positive effect in reducing the percentage of subjects with >105 CFU/mL of MS.
Interim and temporary restoration of teeth during endodontic treatment
Authors: Jensen A‐L , Abbott PV , Salgado J Castro
Published: March 2008

One of the main aims of endodontic treatment is to eliminate micro‐organisms from within the root canal system. A further aim is to prevent the ingress of any further bacteria during and after treatment. These aims are usually achieved by various means and stages throughout the treatment process. Endodontic treatment is usually performed on teeth that have lost the integrity of the external coronal tooth structure which has allowed bacteria to enter the tooth and ultimately reach the pulp space. Further opening of the tooth occurs when an endodontic access cavity is made to allow treatment to be performed. Hence, there will always be a need for interim and temporary restoration of teeth undergoing endodontic treatment. Many different materials and techniques have been proposed, and these proposals have been based on many research reports. The purposes of this article are to review the literature regarding the use of interim and temporary restorations, and to provide recommendations regarding such restorations for clinicians to follow when providing endodontic treatment.
Negative skin friction and the neutral plane
Authors: Matyas Elmer L. , Santamarina J. Carlos
Published: March 2008

Current views indicate that negative skin friction on piles can be mobilized at small relative deformations and should be considered in all designs, primarily for serviceability conditions. An elastic-plastic closed-form solution is presented that permits an estimate of down-drag forces and the location of the neutral plane. It is shown that the conventional rigid-plastic solution may overestimate down-drag forces by as much as 50% and may also overestimate the depth of the neutral plane. Key words : piles, negative skin friction, neutral plane, capacity.
Estimating leachate drawdown due to pumping wells in landfills
Authors: Rowe R Kerry , Nadarajah Preba
Published: March 2008

Pumping (extraction, purge) wells in the waste may be proposed as part of the design of new landfills to backup the leachate underdrain system. These wells are intended to control the leachate mound after there has been a failure of the underdrain system. Pumping wells in the waste have also been proposed to reduce the height in old landfills that are not engineered with a leachate underdrain system. Equations are developed herein for use in estimating the well radius/spacing required to control the leachate mound to a specified level for a number of different assumed conditions and hence can be used to aid the design engineer in assessing the viability of pumping wells in the waste as a leachate control measure. The equations consider the hydraulic conductivity of the waste and the percolation through the cover. It is shown that leakage through the landfill base can be readily considered provided that the leakage through the base is less than 80% of the percolation into the landfill. Anisotropy of the waste is considered. Correction factors are also presented to account for the effect of a reduction in hydraulic conductivity around the well due to biotic and abiotic clogging. The use of the equations is illustrated by examples.

Key words: pumping wells, landfills, leachate control, design, applications, clogging.
Characteristics of biplanar wedge spoil pile instabilities and methods to improve stability
Authors: Ulusay Resat , Çaglan Dinçer , ArIkan Fehmi , Yoleri M Fatih
Published: March 2008

The stability of spoil piles in surface coal mines is an important factor in the successful exploitation of coal reserves. Spoil pile instability must be avoided not only to ensure negligible risk in both personnel and equipement but also to prevent increased production costs. Since mining began at the Eskihisar strip coal mine, southwest Turkey, stability problems have been experienced in both spoil piles adjacent to highwalls (slices) and outside dumping areas. This paper outlines the results of field and laboratory investigations performed to describe the causes and mechanism of pile instabilities threatening production along the highwalls. Back-analysis of failures and monitoring data have revealed that failures occur along planar surfaces that define two-wedge shaped blocks. In addition, shear strength of the moist underclay at the base of piles and changes in the floor dip are the controlling factors in the development of failures. It is also noted that sharp decreases in shear strength after peak values for the the underclay indicated that weak basal planes exhibit a shear strength at or approaching the residual value at the time of failure. Results show that failures are most likely initiated along the spoil – natural ground interface and propagate into spoil mass. Three possible remedial measures have been evaluated by carrying out two-dimentional stability analyses, and the most effective method for improving spoil pile stability appeared to be spreading of a rockfill material on the floor after coal production.

Key words: back-analysis, biplanar wedge failure, pile instability, rockfill blanket, shear strength.
A geogrid reinforced embarkment on peat over organic silt: a case history
Authors: Rowe R Kerry , Mylleville Brian LJ
Published: March 2008

The behaviour of an instrumented section of a full-scale geogrid reinforced embarkment constructed on a very soft deposit of peat overlying organic silt is examined. The results of field monitoring are reportd together with engineering properties of the soils obtained from laboratory tests. The behaviour was analyzed using the finite element method, and the calculated performance is shown to be in good agreement with that observed.

Key words: geogrid, reinforcement, embankment, peat, organic silt.
Two debris flow modes on Mount Cayley, British Columbia
Authors: Lu Z Y , Cruden D M
Published: March 2008

The 1963 landslide on Mount Cayley, British Columbia, began at the head of Dusty Creek, a small tributary of Turbid Creek, a major creek draining Mount Cayley, and terminated at the present confluence of Dusty and Turbid creeks. About 5 × 106 m3 of partially saturated, columnar-jointed dacite and weak pyroclastic rocks moved 2.4 km downstream. The depletion zone contained three separate blocks. The landslide deposits have distinct layers that can be traced back to similar bedrock units in the undisturbed material, which are three times thicker. The accumulation zone is divided by two gullys into three blocks, which preserve, much thinned, different but overlapping portions of the volcanic stratigraphy. The 1984 rock slide on Avalache Creek, 0.8 km away, involved tuff breccia, tuff lapilli, and tuff, all easily broken. Its main track ran over thick snow and ice on the bottom of the creek. Differences in water content and displaced material led to different flow modes: the 1963 fragments formed laminar flows, which supported comparatively undeformed central plugs; the turbulent 1984 flow's deposits have no distinct layers. The two modes, laminar flow and turbulent flow, also formed different types of landslide dams.

Key words: landslide, debris flow, volcano, British Columbia, tuff, lava.
Viscous behaviour of soil under oedometric conditions
Authors: Niemunis Andrzej , Krieg Stefan
Published: March 2008

The viscoplastic constitutive theory of Perzyna, and Olszak and Perzyna has been modified and used to model one-dimensional compression of cohesive, normally consolidated soils. Predictions of the model have been compared with the results of a few nonstandard oedometric tests. The model simplifies the one-dimensional creep theory of Yin and Graham by eliminating the traditional concept of plastic strain. Both stress- and strain-controlled tests are discussed. The reference time t0 used in the literature for the description of creep subsequent to a load step has been shown to be a function of the overconsolidation ratio.

Key words: compression, consolidation, constitutive modelling, creep, viscosity, relaxation.
UNIFIED DESCRIPTION OF (PSEUDO)RAPIDITY DISTRIBUTIONS OF FINAL-STATE PARTICLES PRODUCED IN COLLISIONS AT RELATIVISTIC ENERGIES
Authors: LIU FU-HU
Published: March 2008

The paper presents a fit to rapidity distributions of various hadrons measured in heavy-ion experiments at different beam energies. As examples distributions of various identified hadron species measured at GSI SIS and at BNL RHIC are presented and very good agreement between the fit and the data is found. The basis of the fits is a simple Feynman gas model, namely the two-cylinder gas model, for secondary particle production. The model assumption is that there are projectile and target cylinders that are the sources of emitted particles. The conjecture is that at low and intermediate energies the cylinders overlap totally, at high energy the cylinders overlap partly, while at very high energy a gap appears between the two cylinders.
SUPERSYMMETRIC CONTRIBUTIONS TO B→K π IN THE VIEW OF RECENT EXPERIMENTAL RESULTS
Authors: KHALIL SHAABAN
Published: March 2008

Supersymmetric contributions to the branching ratios and CP asymmetries of B→K π decays are analyzed in view of recent experimental measurements. We show that supersymmetry can still provide a natural solution to the apparent discrepancy between the CP asymmetry results and the Standard Model expectations. We emphasize that chargino contributions may enhance the electroweak penguin effects that can resolve to the puzzle of the CP asymmetries of B→Kπ. We also point out that a nonuniversal A-terms is an essential requirement for this solution.
LOGARITHMIC CORRECTION TO SCALING FOR MULTISPIN STRINGS IN THE AdS5 BLACK HOLE BACKGROUND
Authors: LARSEN A. L.
Published: March 2008

We find new explicit solutions describing closed strings spinning with equal angular momentum in two independent planes in the AdS5 black hole space–time. These are 2n-folded strings in the radial direction and also winding m times around an angular direction. We specially consider these solutions in the long string and high temperature limit, where it is shown that there is a logarithmic correction to the scaling between energy and spin. This is similar to the one-spin case. The strings are spinning, or actually orbiting around the black hole of the AdS5 black hole space–time, similar to the solutions previously found in black hole space–times.
THE NATURE OF TRANSPORT CRITICAL CURRENT DISTRIBUTION IN CERAMIC SAMPLE
Authors: BOGOLYUBOV N. A.
Published: March 2008

It is shown that the transport critical current density in a ceramic sample having any cross-section is a homogeneous function of coordinates.
SOME NOVEL EVOLUTIONAL BEHAVIORS OF LOCALIZED EXCITATIONS IN THE BOITI–LEON–MARTINA–PEMPINELLI SYSTEM
Authors: ZHENG CHUN-LONG , CHEN LI-QUN
Published: March 2008

Using an extended mapping approach and a special Painlevé–Bäcklund transformation, respectively, we obtain two families of exact solutions to the (2+1)-dimensional Boiti–Leon–Martina–Pempinelli (BLMP) system. In terms of the derived exact solution, we reveal some novel evolutional behaviors of localized excitations, i.e., fission, fusion, and annihilation phenomena in the (2+1)-dimensional BLMP system.
KINETICS AND PHOTOELECTRET PHENOMENA OF LAYER SEMICONDUCTOR LASER INTERCALATED BY NICKEL
Authors: GRYGORCHAK I. I. , STAKHIRA P. Y. , FOMENKO V. L. , TOVSTYUK N. K.
Published: March 2008

The mechanisms of the photoelectretic effect appearing on Ni intercalation GaSe were studied. The presence of the photoelectretic effect for such an object of investigation can be explained by the estimation that in Ni intercalated GaSe , the nonequilibrium electrons and holes excited by light occurred on an asymmetric potential well.
STOCHASTIC RESONANCE OF A LINEAR SYSTEM INDUCED BY DICHOTOMOUS NOISE
Authors: ZHOU YU-RONG , GUO FENG , JIANG SHI-QI , PANG XIAO-FENG
Published: March 2008

The stochastic resonance phenomenon in a linear system subject to multiplicative and additive dichotomous noise is investigated. By the use of the linear-response theory and the properties of the dichotomous noise, the exact expressions have been found for the first two moments and the signal-to-noise ratio (SNR). It is shown that the SNR is a non-monotonic function of the correlation time of the additive dichotomous noise, and it varies non-monotonically with the bias of the external field, with the intensity and asymmetry of the multiplicative dichotomous noise, as well as with the external field frequency. Moreover, the SNR depends on the intensity of the cross noise between the multiplicative and additive dichotomous noise, as well as on the strength and asymmetry of the additive dichotomous noise.
CORRELATION BETWEEN FUNCTIONAL ANNOTATION AND TOPOLOGY OF PROTEIN-PROTEIN INTERACTION NETWORK
Authors: HUANG JIUN-YAN
Published: March 2008

The functional annotation of proteins was believed to be related to the topology of the protein-protein interaction network. People utilized the protein-protein interaction network to infer the protein function by various methods. Here, we select the protein interaction data of Saccharomyces cerevisia and calculated the correlation between functional annotation of proteins and the topology of protein-protein interaction network. The result shows that the functional correlation decays exponentially with the distance between two proteins, and beyond the characteristic distance, it has no correlation.
A STUDY ON THE PHOTOLUMINESCENCE PROPERTIES OF POROUS 6H-SiC(p) AND SiC FILM ON p-Si SUBSTRATE
Authors: BOURENANE K. , KEFFOUS A. , KECHOUANE M. , BOURENANE A. , NEZZAL G. , BOUKEZZATA A.
Published: March 2008

P-type porous SiC layers were fabricated by anodization of a hot-pressed p-type 6H-SiC (30 kΩcm) and a 1.6 μm SiC film was deposited onto p-type Si (100) substrate by Pulsed Laser Deposition (PLD) in HF. In order to facilitate the electrochemical etching of the substrate, ethylene glycol electrolyte has been added to the solution and a thin metallic film of aluminium ( Al ) has been deposited onto a SiC prior to anodization. The structure and properties of the porous SiC layer formed by this method were investigated by Scanning Electron Microscopy (SEM) and Photoluminescence (PL). It shows that photoluminescence spectra exhibit two emission bands centered at 2.20 eV (blue band) and an extended broad band from 2.20 to 3.22 eV (green band) from porous 6H-SiC (PSC). On the contrary, porous thin 1.6 μm SiC layer exhibits only a blue band centered at 2.95 eV. Finally, the results indicate clearly that porous SiC gives off green and blue light. Also, there is a shift to blue luminescence with the same order of magnitude when using a thin SiC layer deposited onto silicon (p- Si (100)).
ENERGY GENERATION AND AMPLITUDE OF THERMOMAGNETIC WAVES IN THE CONDUCTING MEDIUM
Authors: HASANOV E. R. , NOVRUZOV M. F. , PANAHOV A. Z. , DEMIREL A. I.
Published: March 2008

The thermomagnetic waves in conducting medium is theoretically studied. The frequencies of these waves are obtained. The amplitude and conditions of radiation by media are determined in the first approximation.