Preloads Generated with Repeated Tightening in Three Types of Screws Used in Dental Implant Assemblies

PURPOSE

Abutment screw loosening, especially in the case of cemented single tooth restorations, is a cause of implant restoration failure. This study compared three screws (titanium alloy, gold alloy, and gold-coated) with similar geometry by recording the preload induced when torques of 10, 20, and 35 Ncm were used for fixation.

MATERIALS AND METHODS

Two abutment types were used-prefabricated preparable abutments and cast-on abutments. A custom-designed rig was used to measure preload in the abutment-screw-implant assembly with a strain gauge. Ten screws of each type were sequentially tightened to 10, 20, and 35 Ncm on ten of the two abutment types. The same screws were then loosened and re-tightened. This procedure was repeated. Thus, each screw was tightened on three occasions to the three insertion torques. A linear regression model was used to analyze the effects on preload values of screw type and abutment type for each of the three insertion torques.

RESULTS

The results indicated that the gold-coated screw generated the highest preloads for all insertion torques and for each tightening episode. Further analysis focused on the effects of screw type and abutment type for each episode of tightening and for each fixation torque. The gold-coated screw, fixed to the prefabricated abutment, displayed higher preloads for the first tightening at 10, 20, and 35 Ncm. Conversely, the same screw fixed to the cast-on abutment showed higher values for the second and third tightening for all fixation torques. All screws showed decay in preload with the number of times tightened. Given the higher preloads generated using the gold-coated screw with both abutment types, it is more likely that this type of screw will maintain a secure joint when tightened for the second and third time.

CONCLUSION

All screw types displayed some decay in preload with repeated tightening, irrespective of abutment type and insertion torque. The gold-coated screw showed markedly higher preloads for all insertion torques and for all instances of tightening when compared with the uncoated screws.

A Collagen-glycosaminoglycan Scaffold Supports Adult Rat Mesenchymal Stem Cell Differentiation Along Osteogenic and Chondrogenic Routes

Adult mesenchymal stem cells have the proclivity to differentiate along multiple lineages giving rise to new bone, cartilage, muscle, or fat. Collagen, a normal constituent of bone, provides strength and structural stability and is therefore a potential candidate for use as a substrate on which to engineer bone and cartilage from their respective mesenchymal-derived precursors. In this study, a collagen- glycosaminoglycan scaffold was used to provide a suitable three-dimensional (3-D) environment on which to culture adult rat mesenchymal stem cells and induce differentiation along the osteogenic and chondrogenic lineages. The results demonstrate that adult rat mesenchymal stem cells can undergo osteogenesis when grown on the collagen-glycosaminoglycan scaffold and stimulated with osteogenic factors (dexamethasone, ascorbic acid, beta-glycerophosphate), as evaluated by the temporal induction of the bone-specific proteins, collagen I and osteocalcin, and subsequent matrix mineralization. The osteogenic factors were coupled to activation of the extracellular-regulated protein kinase (ERK), and this kinase was found to play a role in the osteogenic process. As well as supporting osteogenesis, when the cell-seeded scaffold was exposed to chondrogenic factors (dexamethasone and TGF-1beta), collagen II immunoreactivity was increased, providing evidence that the scaffold can also provide a suitable 3-D environment that supports chondrogenesis.

Multiple dental fractures following tongue barbell placement: a case report

The number of adolescents and young adults undergoing intra-oral piercing, is increasing worldwide. There have been several case reports documenting oral and systemic complications of this practice. These include damage to the dentition, gingivae, infection, speech impediments and nerve damage. The case presented here draws attention to the possibility of multiple tooth fracture as a result of trauma incurred from a barbell inserted into the tongue.

Survey of recent medical graduates' knowledge and understanding of the treatment and prevention of infection

With the increasing interest in infection and antibiotic resistance amongst the general public, we undertook to assess the knowledge, and understanding of the treatment and prevention of common infections in medical graduates, about to commence their intern or pre-registration year. A multiple choice-type questionnaire, which included 19 questions, was circulated to 199 recent graduates of three Irish medical schools and 108 (54.3%) were returned. Approximately 60% of the questions were answered correctly. However, questions on the use of antibiotics were poorly answered compared with other questions. With changes in the curricula of many medical schools, there is a need for better education on infection and the use of antibiotics as well as more sophisticated and validated methods of assessment.

First reported case of endocarditis caused by Candida dubliniensis

Candida dubliniensis is an uncommon cause of bloodstream infection. We describe the first reported case of endocarditis caused by C. dubliniensis and the use of a rapid and novel real-time PCR assay based on the internal transcribed spacer 2 variable region of the rRNA operon that was used to identify this organism.

Inequalities in dementia care across Europe: key findings of the Facing Dementia Survey

The Facing Dementia Survey was undertaken to assess the awareness of and behaviours surrounding Alzheimer's disease (AD) and dementia among all key stakeholders in Europe. Interviews were conducted with more than 2500 persons, including caregivers, members of the general population, physicians, persons with AD and influencers of health care policy. Four key messages emerged from the results. First, AD often remains undiagnosed until symptoms become moderate or severe. This delay may be because of the difficulty of recognising the symptoms of early AD and the attribution of symptoms to so-called normal ageing, the fear of AD common among older people, inadequate screening tools for use by physicians and/or a delay in the confirmation of the diagnosis once suspicion is raised. Second, a majority of respondents perceive their governments as indifferent to the economic, social and treatment burdens associated with AD. Third, a substantial majority of caregivers, physicians and the general population appreciate the wide-ranging impact that AD can have on the quality of life of people who suffer from it and their informal caregivers. While most caregivers reported life-changing negative effects, a few also noted some positive aspects to their experience. Finally, survey results revealed that most caregivers and members of the general public do not have sufficient information about the benefits of treatment and care. The findings of the Facing Dementia Survey support the development of an agenda for change in dementia care across Europe.

Implications of the Facing Dementia Survey for the general population, patients and caregivers across Europe

The Facing Dementia Survey included interviews with approximately 1200 members of the general public, 600 persons who served as primary caregivers for a person with Alzheimer's disease (AD) and 96 persons with AD. Members of the general public and the caregivers indicated level of agreement on a 5-point scale to a series of attitudinal statements about the disease as well as other diagnostic questions. Persons with AD underwent a qualitative interview. Results indicate that Europeans are acutely aware of the potentially devastating consequences of AD, but few are familiar with the early-stage symptoms. Most members of the general population accept that early intervention and therapy are key to slowing the effects of the disease. Caregivers often delayed consulting a physician about a loved one's behaviour, partly because of uncertainty about early signs of AD. They also expressed doubt about the ability of physicians to make the diagnosis. Caregivers experience profound effects of AD in every area of their life--emotional, physical, social and financial. Persons with AD responded to their diagnosis in one of three ways: a fatalistic attitude, a belief that their problems are linked to old age or a lack of acceptance. Survey respondents from three populations were critical of the level of government investment in and support of AD.

Implications of the Facing Dementia Survey for health care professionals across Europe

Approximately 600 general practitioners, primary care physicians and specialists in six European nations (France, Germany, Italy, Poland, Spain and UK) who treat patients with Alzheimer's disease (AD) were interviewed during the Facing Dementia Survey. Compared with generalists, specialists displayed the most optimism regarding the effects of age, believing that health and memory do not inevitably deteriorate as one grows older. Most physician respondents agreed that the diagnosis of AD is too often delayed. A primary reason cited for this delay was the difficulty experienced by both physicians and the general public in identifying early signs of AD. Many physicians believed treatments are available that can slow the disease course. The vast majority surveyed in each nation believed that early treatment of AD can delay disease progression [mean, 87%; range, 68% (United Kingdom) to 96% (Poland)]. More than half of physicians who initiate treatment in France (66%), Germany (59%), Italy (82%), Poland (82%) and Spain (69%) said they institute treatment for AD immediately after diagnosis. The exception was the United Kingdom, where 48% initiated treatment immediately, whereas more than half waited at least a month to start therapy. To a large extent, physicians saw the governments of their countries as a hindrance rather than a help in caring for persons with AD.

Increasing resistance to ciprofloxacin among isolates of Neisseria gonorrhoea in Dublin

Neisseria gonorrhoeae cases are increasing in Ireland. Ciprofloxacin is often used as first line treatment for this infection in STI clinics. A retrospective study to analyze resistance in two Dublin clinics was undertaken. Cases were defined as patients from whom an isolate of N. gonorrhoea was recovered. All cases from two clinics between January 1997 and June 2003 were included. Antimicrobial resistance data was correlated with sex and sexuality. One thousand one hundred and eighty laboratory-confirmed cases were identified. Eighty seven percent were male. Sixty nine percent were MSM. Twenty seven percent of isolates demonstrated reduced susceptibility to penicillin and 6% to ciprofloxacin. Isolates with reduced susceptibility to ciprofloxacin increased year on year from 3.8% in 1997 to 15% in 2003. Prevalence of isolates of N. gonorrhoea with reduced susceptibility to ciprofloxacin has exceeded 10% in these clinics since 2002. In concordance with international guidelines, ceftriaxone became the treatment of choice for gonorrhoea in July 2003.

Targeting c-Myc-activated genes with a correlation method: detection of global changes in large gene expression network dynamics

This work studies the dynamics of a gene expression time series network. The network, which is obtained from the correlation of gene expressions, exhibits global dynamic properties that emerge after a cell state perturbation. The main features of this network appear to be more robust when compared with those obtained with a network obtained from a linear Markov model. In particular, the network properties strongly depend on the exact time sequence relationships between genes and are destroyed by random temporal data shuffling. We discuss in detail the problem of finding targets of the c-myc protooncogene, which encodes a transcriptional regulator whose inappropriate expression has been correlated with a wide array of malignancies. The data used for network construction are a time series of gene expression, collected by microarray analysis of a rat fibroblast cell line expressing a conditional Myc-estrogen receptor oncoprotein. We show that the correlation-based model can establish a clear relationship between network structure and the cascade of c-myc-activated genes.

Community-acquired PVL+ MRSA in Ireland: a preliminary report

Cases of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection were recently detected for the first time in Ireland

Implications of the Facing Dementia Survey for policy makers and third-party organisations across Europe

The Facing Dementia Survey included qualitative interviews conducted with 60 persons who influence health care policies in six European countries (France, Germany, Italy, Poland, Spain and the United Kingdom). Respondents generally reinforced the perception of other survey participants that governments do not adequately fund research into the causes and cure of Alzheimer's disease (AD) and dementia. (AD is the most common cause of dementia, and throughout this discussion, issues raised in reference to AD apply also to dementia in general.) Access to care services and treatment remains highly restricted in some countries and may vary even within countries. Yet, AD presents an enormous but unappreciated social and economic burden for a growing segment of society. AD is associated with unique challenges to health care systems, because diagnosis is difficult and the disease has an enormous impact on the affected persons and their caregivers alike. Moreover, there is a lack of trained professionals to diagnose and manage the disease, a lack of human and financial resources to provide care and services for people with AD as well as their families and a lack of infrastructure to deliver needed services. These difficulties are compounded by inadequate education of both the general public and physicians. Pressure to change current governmental policy towards neurodegenerative diseases may come from the increasing prevalence of AD as the population ages and from broader awareness of the total societal costs of long-term care.

High-density lipoproteins: multifunctional vanguards of the cardiovascular system

The plasma level of high-density lipoprotein (HDL)-cholesterol is inversely correlated with coronary artery disease, the leading cause of death worldwide. HDL particles are thought to mediate the uptake of peripheral cholesterol and, through exchange of core lipids with other lipoproteins or selective uptake by specific receptors, return this cholesterol to the liver for bile acid secretion or hormone synthesis in steroidogenic tissues. HDL particles also act on vascular processes by modulating vasomotor function, thrombosis, cell-adhesion molecule expression, platelet function, nitric oxide release, endothelial cell apoptosis and proliferation. Many of these effects involve signal transduction pathways and gene transcription. Several genetic disorders of HDLs have been characterized at the molecular level. The study of naturally occurring mutations has considerably enhanced understanding of the role of HDL particles. Some mutations causing HDL deficiency are associated with premature coronary artery disease, while others, paradoxically, may be associated with longevity. Modulation of HDL metabolism for therapeutic purposes must take into account, not only the cholesterol content of a particle but its lipid (especially phospholipid) composition, apolipoprotein content, size and charge. Current therapeutic strategies include the use of peroxisome proliferating activator receptor-alpha agonists (fibrates) that increase apolipoprotein AI production and increase lipoprotein lipase activity, statins that have a small effect on HDL-cholesterol but markedly reduce low-density lipoprotein-cholesterol, the cholesterol/HDL-cholesterol ratio and niacin that increases HDL-cholesterol. Potential therapeutic targets include inhibition of cholesteryl ester transfer protein, modulating the ATP-binding cassette A1 transporter, and decreasing HDL uptake by scavenger receptor-B1. Novel therapies include injection of purified apolipoprotien AI and short peptides taken orally, mimicking some of the biological effects of apolipoprotein AI.

The influence of some different factors on the accuracy of shade selection

The purpose of this study was to elucidate some of the factors on which accurate shade taking depends. Custom shade tabs (0.5, 1.0 and 1.5 mm porcelain thickness) were fabricated from selected Vita and Shofu porcelains. Four main factors were investigated, namely, the difference between the two types of porcelain used, the effect of light quality, the effect of porcelain thickness and the experience of the observer. The chi-square test for independence at a probability level of P <0.05 was used to analyse the results. The results indicated that in ideal light there was no difference between the two porcelains (P=0.58). The experienced observers proved better than the novice observers in ideal light conditions (P=0.003). Thickness was also significant in the overall results (P=0.0001), in that thicker samples gave more accurate results. The results indicate that in adverse light, there was an overall difference between the two porcelains (P=0.046), but no difference between the experienced and novice observers. The thickness made no difference to the experienced or the novice observer in adverse light. These results indicate that the most influential factor on shade taking was the light quality (P <0.0001); better results were obtained overall for the ideal light situation. In ideal light thicker samples gave better results (P=0.0001).

Influence of preapheresis clinical factors on the efficiency of CD34+ cell collection by large-volume apheresis

We evaluated 120 leukapheresis procedures (93 patients), in order to detect clinical factors that influence the efficiency of CD34+ collection using Cobe Spectra trade mark cell separators. Hematocrit was >27% and platelet count >30 000/microl in >95% of patients. Platelet transfusions were given if the postprocedure count was &<20 000/microl. Multiple regression analysis was used to analyze putative factors, and a predictive equation defined by stepwise regression modeling. The mean efficiency was 0.59 (s.d. 0.27). Sex (M>F; P=0.01), the volume processed (inversely; P=0.01) and CD34+ cell count (inversely; P=0.04) were associated with efficiency, whereas hematocrit, platelet or leukocyte count, catheter type and patient weight were not. The effect size for predictive factors was small (R(2)=0.21). Adverse events were limited to hypocalcemia. We conclude that female sex, volume processed and CD34+ cell count adversely influence the efficiency of CD34+ cell leukapheresis. However, the impact of volume and CD34+ cell count is small, and likely to be offset by the influence of these same factors on overall yield. Leukapheresis appears to be safe and efficient for autologous blood and marrow transplantation patients with hematocrit >27% and platelet count >30 000/microl.

Health status and participation in a range of activities in an Australian community

INTRODUCTION

The aim of the research was to determine the relationship between levels of participation in a community and self-assessed health status of people in a rural and regional setting.

METHOD

A cross-sectional design, using a mailed, self-administered questionnaire was used. Questionnaires were mailed to a random sample of people aged 18 years and over who were registered on the electoral roll of a regional city and rural area, the Barwon and Otway regions of Victoria, Australia. The sample consisted of 1752 participants: 990 females (57%), 739 males (42%) and 23 sex undisclosed (1%). The range of participants was 18-98 years, and the mean age was 50.53 years (SD = 17.19).

RESULTS

Self-assessed physical and mental health were measured using the SF-12 scale. Participants with low incomes, and those with low self-assessed physical and mental health scores, were significantly more likely than other participants to agree with one or more of the social isolation items, indicating that they experienced some social isolation. Low levels of participation in social, sports, leisure or support activities were associated with low self-assessed physical and mental health. Disengagement with the local community was associated with low levels of self-assessed mental health. While younger people were more likely than older people to participate in social, sports, leisure or support activities, they were less involved as members of their community. Females were more likely than males to have been involved in five or more sports, leisure or support activities. Participation in civic activities was associated with high income. Levels of participation in the four different types of activities were combined (social activities, sport, leisure or support activities, community and group activities, and civic activities). Participants classified as low participators were more likely to be older participants, to have a low income and to have low scores for both physical and mental health.

CONCLUSION

An association was found between health and community participation in a range of activities, and between health and engagement with the community in this rural and regional population. These findings are consistent with those reported from similar research with a metropolitan population sample. The current research suggests that the groups of people of most concern in terms of low participation rates, are people who have low incomes, people aged over 65 years, people who may be defined as possessing poor physical health and people who may be defined as possessing poor mental health. The relationship between age, community participation and health is complex and needs further exploration because it is not known whether poor health reduces community participation or whether reduced community participation results in poor health. However, current research suggests that developing and implementing strategies to promote people's engagement with and involvement in their local community is one important way of promoting the health of the community as a whole.

Flame treatment for the selective wetting and separation of PVC and PET

Flame treatment has been used for many years to modify the surface of plastics to allow coatings to be added. The effect of the treatment is to produce hydrophilic species on the surface of the plastic making it water-wettable. The production of hydrophilic plastic surfaces is also required in the selective separation of plastics by froth flotation. For the process to be selective one plastic must be rendered hydrophilic while another remains hydrophobic. In this study the potential for separation of PVC and PET has been investigated. Flame treatment was shown to be very effective in producing a hydrophilic surface on both plastics, although the process was not selective under the conditions investigated. Raising the temperature of the plastics above their softening point produced a hydrophobic recovery. As the softening point of PVC was significantly lower than for PET it was possible to produce a significant difference in hydrophobicity, as judged using contact angle measurement. When immersed in water the contact angle of the PVC was found to be strongly dependent on the pH. Good separation efficiency of the two plastics was achieved by froth flotation from pH 4 to 9. One particular advantage of the technique is that no chemical reagents may be required in the flotation stage. The practicalities of designing a flake treatment system however have to be addressed before considering it to be a viable industrial process.

Adenoviral delivery of A-FOS, an AP-1 dominant negative, selectively inhibits drug resistance in two human cancer cell lines

Activator protein-1 (AP-1) transcription factor has been linked to chemotherapeutic resistance. To assess the clinical efficacy of AP-1 inhibition toward reversing drug resistance, we have developed an adenovirus expressing a dominant negative that inhibits AP-1 DNA binding, namedAdA-FOS. We examined the consequence of AdA-FOS infection on two paired human cancer cell lines, each pair consisting of a parental cell and the drug- resistant derivative. The first pair of cells is the parental human ovarian cancer cell line A2780 and the cisplatin-resistant A2780/CP70 cell line. The second pair of cells is the parental epidermal carcinoma cell line KB8 and the multidrug-resistant (mdr) KB85 cell line. Because of an association of up-regulated AP-1 activity with their drug resistance, these cell lines were considered good targets of AdA-FOS therapy. Following infection of the drug-sensitive and drug-resistant cells, we observed a significant decrease in cell viability of KB85 and A2780/CP70 cells at drug doses normally not lethal to the cell. The parental cell lines, A2780 and KB8 cells, were not similarly affected by AdA-FOS. This decrease in viability was specific to AdA-FOS as an adenovirus control (Advector) did not reverse drug resistance. Although the efficiency of AdA- FOS in therapy would need to be further analyzed with other cisplatin-resistant and mdr cell lines, these results suggest that AP-1 is a therapeutic molecular target and that inhibition of AP-1 DNA binding may be of clinical value in treating chemotherapeutic resistance.

3.2 Ensuring research productivity in the future faculty

The group concluded that the research productivity of a dental school depended to a large extent on the availability of resources, human and economic. Firstly it requires a group of individuals trained and educated to conduct independent research. Secondly, it requires that these individuals had time to spend on research activities. Thirdly, appropriate space and equipment in which to conduct the research were considered prerequisites. Fourthly, they require an ongoing and appropriate budget. Fifthly, it is essential to have an appropriate climate in the school that encourages and rewards research achievement.

Recovery after stroke: a qualitative perspective

The purpose of this study was to determine the impact of stroke on survivors of the condition and to identify their physical and psychosocial needs in rural and regional settings. Data were collected via focus group interviews with stroke survivors, carers and key informants. Data were managed using NUD*IST and analysed using a content analysis method identifying major themes related to the impact of living in the community after having a stroke. It was found that stroke survivors suffered severe physical and emotional effects. The findings also identified the vulnerability of this group and a lack of organised, on-going psychosocial and rehabilitative support. Recommendations are made to enhance the current management of stroke after the acute and subacute phases.