bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Trigeminal Nerve Injury
Authors: Holland G.R.
Published: January 2009

The successful reinnervation of peripheral targets after injury varies with the axonal population of the nerve that is injured and the extent of the dislocation of its central component from the peripheral endoneurial tube. Larger-diameter axons such as those supplying mechanoreceptors recover more readily than narrower axons such as those supplying taste. A complex, bi-directional interaction between lingual epithelium and sprouting nerve results in the redifferentiation of taste buds after denervation. Dentin and the dental pulp provide a strong attraction to sprouting nerves and will become reinnervated from collateral sources if recovery of the original innervation is blocked. The most effective repair technique for transected lingual nerves is one which brings the cut ends together rather than one that provides a temporary bridge.

Injuries can result in cell death in the trigeminal ganglion but only if the injury is severe and recovery is prevented. Lesser damage results in chromatolysis and the increased expression of neuropeptides. All nerve injuries bring about changes in the trigeminal nucleus. These occur as changes in receptive field and the incidence of spontaneously active neurons, effects which are consistent with the unmasking of existing afferents. These functional changes are short-lived and reversible. Morphologically, nerve injury results in terminal degeneration in the nuclei and an increased expression of the c-Fos gene and some neuropeptides. Only a chronic constriction injury induces behavioral changes. The adult trigeminal system retains considerable plasticity that permits it to respond successfully to nerve injury. Much remains to be learned about this response, particularly of the trophic factors that control peripheral recovery and the central response to more severe injuries.
Periodontitis vs. Peri-Implantitis: The Same Disease? The Same Treatment?
Authors: Meffert R.M.
Published: January 2009

The microbial flora in the natural dentition sulcus/pocket and the implant crevice/pocket is very similar in both health and disease. In health, coccal forms predominate, and in disease, large numbers of Gram-negative pathogens are associated with both tooth and implant. It has also been demonstrated that the bacteria in the partially edentulous implant case may be more pathogenic (especially Gram-negative rods and spirochetes) than in the fully edentulous case, indicating a possible seeding mechanism from tooth pocket to implant crevice. Detoxification procedures involving the use of tetracycline and citric acid prior to regenerative procedures with the use of barrier membranes and grafting materials are necessary, and the same problems attendant to premature exposure of the barrier membrane(s) in the natural dentition situation apply to the implant case. It is apparent that periodontitis = peri-implantitis in etiology and therapy.
The Role of Implant Surface Characteristics in the Healing of Bone
Authors: Kieswetter K. , Schwartz Z. , Dean D.D. , Boyan B.D.
Published: January 2009

The surface of an implant determines its ultimate ability to integrate into the surrounding tissue. The composite effect of surface energy, composition, roughness, and topography plays a major role during the initial phases of the biological response to the implant, such as protein adsorption and cellular adherence, as well as during the later and more chronic phases of the response.

For bone, the successful incorporation (and hence rigid fixation) of an alloplastic material within the surrounding bony bed is called osteointegration. The exact surface characteristics necessary for optimal osteointegration, however, remain to be elucidated. This review will focus on how surface characteristics, such as composition and roughness, affect cellular response to an implant material. Data from two different culture systems suggest that these characteristics play a significant role in the recruitment and maturation of cells along relevant differentiation pathways. In the case of osteointegration, if the implant surface is inappropriate or less than optimal, cells will be unable to produce the appropriate complement of autocrine and paracrine factors required for adequate stimulation of osteogenesis at the implant site. In contrast, if the surface is appropriate, cells at the implant surface will stimulate interactions between cells at the surface and those in distal tissues. This, in turn, will initiate a timely sequence of events which include cell proliferation, differentiation, matrix synthesis, and local factor production, thereby resulting in the successful incorporation of the implant into the surrounding bony tissue.
Pioneers in Oral Biology: The Migrations of Gottlieb, Kronfeld, Orban, Weinmann, and Sicher From Vienna To America
Authors: Kremenak Nellie W. , Squier Christopher A.
Published: January 2009

Following the annexation of Austria by Hitler's Germany in 1938, officials at the eminent University of Vienna Medical School purged faculty ranks of lews. Among those forced out were several distinguished physician dentists, several of whom emigrated to the United States. The assimilation of foreign-trained dentists raised questions at national meetings of the AADS and the National Association of Dental Examiners. Already existing ties between dental schools in Chicago and the University of Vienna, including the 1928 appointment of Rudolf Kronfeld to the faculty at Loyola, led to the relocation of Balint Orban, Harry Sicher, and Joseph Peter Weinmann in that city. Bernhard Gottlieb, who had been director of the Dental Institute in Vienna, transplanted less easily, but eventually found a niche at the Baylor College of Dentistry in Dallas. The careers of the Vienna dentist-scientists strengthened the scientific foundations of clinical dentistry in the United States, contributed to the development of a stronger research establishment, and enlarged the scope of oral biology.
Managed Care and Dental Education and Research: Should Academicians Be Concerned?
Authors: Bailit Howard
Published: January 2009

This paper examines the restructuring of the delivery system resulting from managed care. As HMOs consolidate to a few large companies in urban areas, they put great pressure on medical providers to reduce their costs and excess delivery capacity. In this environment, academic health centers face serious problems, because HMOs are reluctant to pay their higher charges, and public educational subsidies are declining. Managed care is unlikely to have the same impact on dentistry. Although managed dental care is growing, most Americans will not be enrolled, since they do not have dental insurance. Also, the supply of dentists is starting to decline, increasing the relative demand for dental services. Managed care will have only a limited direct impact on most dental schools, but a significant indirect effect. As academic health center budgets are reduced, all health professional schools can expect to contribute to solving the financial problems of University hospitals and medical schools. The response of dental academicians to these challenges will determine the future of dental education and research for the next decade. Bold new initiatives are needed to find new sources of revenue to support educational and research programs.
The Effect of Fluoride On Apatite Structure and Growth
Authors: Aoba T.
Published: January 2009

Fluoride participates in many aspects of calcium phosphate formation in vivo and has enormous effects on the process and on the nature and properties of formed mineral. The most well-documented effect of fluoride is that this ion substitutes for a column hydroxyl in the apatite structure, giving rise to a reduction of crystal volume and a concomitant increase in structural stability. In the process of enamel mineralization during amelogenesis (a unique model for the cell-mediated formation of well-crystallized carbonatoapatite), free fluoride ions in the fluid phase are supposed to accelerate the hydrolysis of acidic precursor(s) and increase the driving force for the growth of apatitic mineral. Once fluoride is incorporated into the enamel mineral, the ion likely affects the subsequent mineralization process by reducing the solubility of the mineral and thereby modulating the ionic composition in the fluid surrounding the mineral, and enhancing the matrix protein-mineral interaction. But excess fluoride leads to anomalous enamel formation by retarding tissue maturation. It is worth noting that enameloid/enamel minerals found in vertebrate teeth have a wide range of CO3 and fluoride substitutions. In the evolutionary process from elasmobranch through teleost enameloid to mammalian enamel, the biosystems appear to develop regulatory functions for limiting the fluoridation of the formed mineral, but this development is accompanied by an increase of carbonate substitution or defects in the mineral. In research on the cariostatic effect of fluoride, considerable emphasis is placed on the roles of free fluoride ions (i.e., preventing the dissolution and accelerating the kinetics of remineralization) in the oral fluid bathing tooth mineral. Fluoride also has been used for the treatment of osteoporosis, but much still remains to be learned about maximizing the benefit and minimizing the risk of fluoride when used as a public health measure.
Tissue Engineering, Morphogenesis, and Regeneration of the Periodontal Tissues By Bone Morphogenetic Proteins
Authors: Ripamonti Ugo , Hari Reddi A.
Published: January 2009

Tissue engineering is the emerging field of science developing techniques for fabrication of new tissues for replacement based on principles of cell and developmental biology and biomaterials. Morphogenesis is the cascade of pattern formation and the attainment of form of the various organs and the organism as a whole. The periodontium consists of the periodontal ligament, cementum, and alveolar bone. Bone has considerable potential for regeneration and therefore is a prototypic model for tissue engineering. The three main ingredients for tissue engineering are regulatory signals, responding stem cells, and extracellular matrix. Recent advances in molecular biology of the bone morphogenetic proteins (BMPs) have set the stage for tissue engineering of bone and related tissues, including the periodontium. Bone-derived BMPs, with a collagenous matrix as carrier, induced cementum and alveolar bone regeneration in surgically created furcation defects in the primate. It is noteworthy that there was morphogenesis of periodontal ligament and a faithful insertion of Sharpey's fibers into cementum. In the same furcation model, recombinant human osteogenic protein-1 (rhOP-1, also known as BMP-7), in conjunction with the collagenous carrier, induced extensive cementogenesis with insertion of Sharpey's fibers into the newly formed cementum. The observation that BMPs induce cementogenesis and periodontal ligament formation indicates that these proteins may have multiple functions in vivo not limited to cartilage and bone induction. The rapid advances in the molecular biology of BMPs and their receptors bode well for novel strategies to engineer the regeneration of the periodontal tissues.
Graft-vs.-Host Disease
Authors: Woo Sook-Bin , Lee Stephanie Joi , Schubert Mark M.
Published: January 2009

Bone marrow transplantation (BMT) is the treatment of choice for many leukemias, lymphomas, bone marrow failure syndromes, and immundeficiency disorders, and is the primary and salvage therapy for many solid malignancies. With the establishment of national and international marrow banks, unrelated allogeneic BMT is being performed with increasing frequency. Graft-vs.-host disease (GVHD) remains a major complication of allogeneic BMT, occurring in 25% to 70% of patients despite GVHD prophylaxis, with the skin, gastro-intestinal tract, and liver as primary target organs. Oral findings are seen in both acute and chronic GVHD. In acute GVHD, the oral lesions are often painful, erythematous, ulcerative, and desquamative. In chronic GVHD, they are lichenoid with associated erythema and ulcerations; additionally, they may be associated with a sicca syndrome characterized by xerostomia and progressive salivary gland atrophy. General principles of BMT are discussed, as are systemic and local therapeutic options for oral GVHD.
Current Concepts On Adhesion To Dentin
Authors: Eick J.D. , Gwinnett A.J. , Pashley D.H. , Robinson S.J.
Published: January 2009

This review examines fundamental concepts in bonding to dentin. Emphasis is placed on the structure and permeability characteristics of dentin and how they may influence its interaction with adhesive resin. Several new techniques to examine the interfaces between resin and dentin are reviewed along with some of their limitations. The advantages and disadvantages of acid etchants/conditioners vs. self-etching conditioners/primers are discussed. The problems of matching the surface tension of resin-bonding systems to the surface energy of the substrate are reviewed in terms of wetting the various components of dentin. The problems associated with matching the permeability of intertubular dentin to the diffusibility of bonding reagents are explored. Speculation is advanced on how to ensure polymerization and wetting of dentinal collagen. Theoretical problems associated with dentin bonding and with bond testing are reviewed to encourage future research in this rapidly developing area.
Leukocyte Adhesion Molecules
Authors: Penberthy Timothy W. , Yanling Jiang  , Graves Dana T.
Published: January 2009

Recruitment of leukocytes is critical to many of the processes studied in oral biology. With the development of new tools such as monoclonal antibody production and transgenic mice, the specific adhesion molecules thought to be important in leukocyte recruitment have been identified and their function examined. These molecules can be divided into three major classes: selectins, members of the immunoglobulin superfamily, and integrins. They mediate interactions between leukocytes and endothelial cells, facilitating the initial process of leukocyte rolling, firm attachment to endothelium, transendothelial migration, diapedesis, and migration along connective tissue. The goal of this paper is to provide an understanding of which molecules are involved in the above processes by discussing their cellular distribution, counter-receptors, and physiologic function.
Mercury Exposure From Dental Amalgam Fillings: Absorbed Dose and the Potential for Adverse Health Effects
Authors: Mackert J.R. , Berglund A.
Published: January 2009

This review examines the question of whether adverse health effects are attributable to amalgam-derived mercury. The issue of absorbed dose of mercury from amalgam is addressed first. The use of intra-oral Hg vapor measurements to estimate daily uptake must take into account the differences between the collection volume and flow rate of the measuring instrument and the inspiratory volume and flow rate of air through the mouth during inhalation of a single breath. Failure to account for these differences will result in substantial overestimation of the absorbed dose. Other factors that must be considered when making estimates of Hg uptake from amalgam include the accurate measurement of baseline (unstimulated) mercury release rates and the greater stimulation of Hg release afforded by chewing gum relative to ordinary food. The measured levels of amalgam-derived mercury in brain, blood, and urine are shown to be consistent with low absorbed doses (1-3 μg/day). Published relationships between the number of amalgam surfaces and urine levels are used to estimate the number of amalgam surfaces that would be required to produce the 30 μg/g creatinine urine mercury level stated by WHO to be associated with the most subtle, pre-clinical effects in the most sensitive individuals. From 450 to 530 amalgam surfaces would be required to produce the 30 μg/g creatinine urine mercury level for people without any excessive gum-chewing habits. The potential for adverse health effects and for improvement in health following amalgam removal is also addressed. Finally, the issue of whether any material can ever be completely exonerated of claims of producing adverse health effects is considered.
Tobacco and Smoking: Environmental Factors That Modify the Host Response (Immune System) and Have an Impact On Periodontal Health
Authors: Barbour Suzanne E. , Nakashima Keisuke , Zhang Ji-Bo , Tangada Srilatha , Hahn Chin-Lo , Schenkein Harvey A. , Tew John G.
Published: January 2009

This review summarizes the current data on the effects of smoking and tobacco on the immune system and its potential impact on periodontal health. Smokers are 2.5-6 times more likely to develop periodontal disease than non-smokers, and there is evidence for a direct correlation between the number of cigarettes smoked and the risk of developing disease. Tobacco users also tend to exhibit increased severity of periodontal disease. Direct correlations between tobacco use and increased attachment loss and pocket depth and reduced bone crest height have been reported.

Although the correlation between tobacco use and periodontal disease is quite strong, the role of tobacco in the pathogenesis of periodontal disease is uncertain. Recent studies indicate that one potential mechanism is that tobacco use exacerbates periodontal disease because it alters the immune response to periodontal pathogens. Indeed, smokers exhibit increased numbers of peripheral blood mononuclear phagocytes which appear to be functionally compromised. Inadequate phagocyte activity could reduce the clearance of pathogens from the oral cavity and thereby facilitate the development of periodontal disease Tobacco-exposed B- and T-lymphocytes exhibit reduced proliferative capacities which could limit the production of protective immunoglobulins against oral pathogens.

The risk factors for periodontal disease can be broadly classified as genetic, environmental, host-response factors, and host-related factors such as age. Tobacco, an environmental factor, undermines the host response and may facilitate the development and progression of periodontal disease. This review highlights the inter-relatedness of two of the risk factors associated with periodontal disease.
Neural Tube and Craniofacial Defects With Special Emphasis On Folate Pathway Genes
Authors: Finnell R. H. , Greer K. A. , Barber R. C. , Piedrahita J. A. , Shaw G. M. , Lammer E. J.
Published: January 2009

Neural tube and orofacial defects are common congenital malformations in humans. While etiologically heterogeneous, they are for the most part multifactorial in their pathogenesis, having both genetic and environmental components in their development. In recent years, there has been a great deal of epidemiologic evidence demonstrating that women who received multivitamins containing folic acid periconceptionally had significantly reduced occurrence and recurrence risks for producing infants with such malformations. This risk reduction is not observed in all populations, further suggestive of a genetic regulation of this phenomenon. Unfortunately, the mechanisms underlying the beneficial effects of folic acid are not well-understood. In this article, we review the relevant epidemiologic data on both neural tube defects and orofacial malformations, the fundamental embryological processes involved in closing the neural tube, and the development of the craniofacies, and propose a working hypothesis for susceptibility to these malformations. This hypothesis is based on the interworkings of cellular folate transport, focusing on the key elements involved in potocytosis. We propose that infants with mutations in the folate receptor alpha gene might be at increased risk for congenital anomalies due to a reduced binding affinity for 5-methyltetrahydrofolate, the physiologic form of folic acid. Various experimental approaches to test the working hypothesis are considered.
Survival of Oral Bacteria
Authors: Bowden G. H.W. , Hamilton I. R.
Published: January 2009

The global distribution of individual species of oral bacteria demonstrates their ability to survive among their human hosts. Such an ubiquitous existence is the result of efficient transmission of strains and their persistence in the oral environment. Genetic analysis has identified specific clones of pathogenic bacteria causing infection. Presumably, these express virulence-associated characteristics enhancing colonization and survival in their hosts. A similar situation may occur with the oral resident flora, where genetic variants may express specific phenotypic characteristics related to survival. Survival in the mouth is enhanced by dental plaque formation, where persistence is associated with the bacteria's capacity not only to adhere and grow, but also to withstand oxygen, wide fluctuations in pH and carbohydrate concentration, and a diverse array of microbial interactions. Streptococcus mutans has been discussed as a 'model' organism possessing the biochemical flexibility that permits it to persist and dominate the indigenous microflora under conditions of stress.
Cytokine Expression in Periodontal Health and Disease
Authors: Okada H. , Murakami S.
Published: January 2009

Soluble proteins that serve as mediators of cell function and are produced by various cell types, such as structural and inflammatory cells, are collectively called cytokines. Several lines of evidence have revealed that cytokines play important roles not only in tissue homeostasis but also in the pathogenesis of many infectious diseases. Recent research on biological activities in normal periodontium and the pathogenesis of periodontal diseases has clarified the involvement of various cytokines in the biological activities observed in the sites. Cytokines play crucial roles in the maintenance of tissue homeostasis, a process which requires a delicate balance between anabolic and catabolic activities. In particular, growth factors-such as fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), insulin-like growth factor (IGF), transforming growth factor-β (TGF-β)—are thought to play important roles in modulating the proliferation and/or migration of structural cells in the periodontium and the production of various extracellular matrices by these cells. On the other hand, there is little doubt that excessive and/or continuous production of cytokines in inflamed periodontal tissues is responsible for the progress of periodontitis and periodontal tissue destruction. Particularly, inflammatory cytokines-such as IL-la, 1L-1β, IL-6, and IL-8-are present in the diseased periodontal tissues, and their unrestricted production seems to play a role in chronic leukocyte recruitment and tissue destruction. It is possible that monitoring cytokine production or its profile may allow us to diagnose an individual's periodontal disease status and/or susceptibility to the disease. In addition, although the hypothesis is still controversial, it has been suggested that discrete T-cell subsets (Thl and Th2) with different cytokine profiles play specific roles in the immunopathogenesis of periodontal diseases.
Oral Splints: the Crutches for Temporomandibular Disorders and Bruxism?
Authors: Dao T.T. , Lavigne GJ
Published: January 2009

Despite the extensive use of oral splints in the treatment of temporomandibular disorders (TMD) and bruxism, their mechanisms of action remain controversial. Various hypotheses have been proposed to explain their apparent efficacy (i.e., true therapeutic value), including the repositioning of the condyle and/or the articular disc, reduction in the electromyographic activity of the masticatory muscles, modification of the patient's "harmful" oral behavior, and changes in the patient's occlusion. Following a comprehensive review of the literature, it is concluded that any of these theories is either poor or inconsistent, while the issue of true efficacy for oral splints remains unsettled. However, the results of a controlled clinical trial lend support to the effectiveness (i.e., the patient's appreciation of the positive changes which are perceived to have occurred during the trial) of the stabilizing splint in the control of myofascial pain. In light of the data supporting their effectiveness but not their efficacy, oral splints should be used as an adjunct for pain management rather than a definitive treatment. For sleep bruxism, it is prudent to limit their use as a habit management aid and to prevent/limit dental damage potentially induced by the disorder. Future research should study the natural history and etiologies of TMD and bruxism, so that specific treatments for these disorders can be developed.
Proteoglycans At the Bone-Implant Interface
Authors: Klinger M.M. , Rahemtulla F. , Prince C.W. , Lucas L.C. , Lemons J.E.
Published: January 2009

The widespread success of clinical implantology stems from bone's ability to form rigid, load-bearing connections to titanium and certain bioactive coatings. Adhesive biomolecules in the extracellular matrix are presumably responsible for much of the strength and stability of these junctures. Histochemical and spectroscopic analyses of retrievals have been supplemented by studies of osteoblastic cells cultured on implant materials and of the adsorption of biomolecules to titanium powder. These data have often been interpreted to suggest that proteoglycans permeate a thin, collagen-free zone at the most intimate contact points with implant surfaces. This conclusion has important implications for the development of surface modifications to enhance osseointegration. The evidence for proteoglycans at the interface, however, is somewhat less than compelling due to the lack of specificity of certain histochemical techniques and to possible sectioning artifacts. With this caveat in mind, we have devised a working model to explain certain observations of implant interfaces in light of the known physical and biological properties of bone proteoglycans. This model proposes that titanium surfaces accelerate osseointegration by causing the rapid degradation of a hyaluronan meshwork formed as part of the wound-healing response. It further suggests that the adhesive strength of the thin, collagen-free zone is provided by a bilayer of decorin proteoglycans held in tight association by their overlapping glycosaminoglycan chains.
Antibiotic Resistance in Oral/Respiratory Bacteria
Authors: Roberts M.C.
Published: January 2009

In the last 20 years, changes in world technology have occurred which have allowed for the rapid transport of people, food, and goods. Unfortunately, antibiotic residues and antibiotic-resistant bacteria have been transported as well. Over the past 20 years, the rise in antibiotic-resistant gene carriage in virtually every species of bacteria, not just oral/respiratory bacteria, has been documented. In this review, the main mechanisms of resistance to the important antibiotics used for treatment of disease caused by oral/respiratory bacteria-including β-lactams, tetracycline, and metronidazole-are discussed in detail. Mechanisms of resistance for macrolides, lincosamides, streptogramins, trimethoprim, sulfonamides, aminoglycosides, and chloramphenicol are also discussed, along with the possible role that mercury resistance may play in the bacterial ecology.
Dental Injury Models: Experimental Tools for Understanding Neuroinflammatory Interactions and Polymodal Nociceptor Functions
Authors: Byers M.R. , Narhi M.V.O.
Published: January 2009

Recent research has shown that peripheral mechanisms of pain are much more complex than previously thought, and they differ for acutely injured normal tissues compared with chronic inflammation or neuropathic (nerve injury) pain. The purpose of the present review is to describe uses of dental injury models as experimental tools for understanding the normal functions of polymodal nociceptive nerves in healthy tissues, their neuroinflammatory interactions, and their roles in healing. A brief review of normal dental innervation and its interactions with healthy pulp tissue will be presented first, as a framework for understanding the changes that occur after injury. Then, the different types of dental injury that allow gradation of the extent of tissue damage will be described, along with the degree and duration of inflammation, the types of reactions in the trigeminal ganglion and brainstem, and the type of healing. The dental injury models have some unique features compared with neuroinflammation paradigms that affect other peripheral tissues such as skin, viscera, and joints. Peripheral inflammation models can all be contrasted to nerve injury studies that produce a different kind of neuroplasticity and neuropathic pain. Each of these models provides different insights about the normal and pathologic functions of peripheral nerve fibers and their effects on tissue homeostasis, inflammation, and wound healing. The physical confinement of dental pulp and its innervation within the tooth, the high incidence of polymodal A-delta and C-fibers in pulp and dentin, and the somatotopic organization of the trigeminal ganglion provide some special advantages for experimental design when dental injury models are used for the study of neuroinflammatory interactions.
Denture Plaque and Adherence of Candida Albicans To Denture-Base Materials in Vivo and in Vitro
Authors: Radford D.R. , Challacombe SJ , Walter J.D.
Published: January 2009

The aim of this paper is to review our understanding of the mechanisms and clinical significance of adhesion of C. albicans to denture-base materials in relation to denture plaque and denture-related stomatitis. Earlier reports in the literature of a 65% prevalence level of denture-related stomatitis seem to be exaggerated. More recent studies indicate that denture-related stomatitis is considerably less common, particularly in normal healthy subjects. The etiology of the condition is discussed in this review, and although much of the literature supports the view that the condition is strongly associated with C. albicans, this is not always so. In some subjects, the cause appears to be related to a non-specific plaque. This review also considers the role of denture plaque in the pathogenesis of denture-related stomatitis, the sequential development of denture plaque, and its colonization by Candida organisms. Designing controlled in vivo studies is difficult, and as a consequence, many investigators have had to resort to in vitro studies. The majority of these studies have attempted to investigate the hydrophobicity of C. albicans, relating the surface free-energy of denture-base materials, particularly acrylic resin, to that of the organism. Surprisingly little work has been directed at surface roughness and how it affects retention of organisms. Further, no attention has been paid to the properties and character of the surface, other than average surface roughness, as it affects adhesion. A comparison of results from in vitro studies on the effect on adhesion of pre-coating the surfaces of denture-base materials with saliva has produced equivocal conclusions. This is largely due to little standardization of experimental protocols between studies, particularly in the collection and handling of the saliva used. In conclusion, the review strongly supports the suggestion that adherence of C. albicans to denture-base materials in vitro is related to the hydrophobicity of the organism. The clinical significance of the observation and the mechanisms for the development and maturation of denture plaque are yet to be understood. There is a clear need for further investigation of other factors that may moderate the adhesion of organisms and subsequent colonization of denture-base materials.
The Ruffini Ending as the Primary Mechanoreceptor in the Periodontal Ligament: Its Morphology, Cytochemical Features, Regeneration, and Development
Authors: Maeda T. , Ochi K. , Nakakura-Ohshima K. , Youn S.H. , Wakisaka S.
Published: January 2009

The periodontal ligament receives a rich sensory nerve supply and contains many nociceptors and mechanoreceptors. Although its various kinds of mechanoreceptors have been reported in the past, only recently have studies revealed that the Ruffini endings-categorized as low-threshold, slowly adapting, type II mechanoreceptors-are the primary mechanoreceptors in the periodontal ligament. The periodontal Ruffini endings display dendritic ramifications with expanded terminal buttons and, furthermore, are ultrastructurally characterized by expanded axon terminals filled with many mitochondria and by an association with terminal or lamellar Schwann cells. The axon terminals of the periodontal Ruffini endings have finger-like projections called axonal spines or microspikes, which extend into the surrounding tissue to detect the deformation of collagen fibers. The functional basis of the periodontal Ruffini endings has been analyzed by histochemical techniques. Histochemically, the axon terminals are reactive for cytochrome oxidase activity, and the terminal Schwann cells have both non-specific cholinesterase and acid phosphatase activity. On the other hand, many investigations have suggested that the Ruffini endings have a high potential for neuroplasticity. For example, immunoreactivity for p75-NGFR (low-affinity nerve growth factor receptor) and GAP-43 (growth-associated protein-43), both of which play important roles in nerve regeneration/development processes, have been reported in the periodontal Ruffini endings, even in adult animals (though these proteins are usually repressed or down-regulated in mature neurons). Furthermore, in experimental studies on nerve injury to the inferior alveolar nerve, the degeneration of Ruffini endings takes place immediately after nerve injury, with regeneration beginning from 3 to 5 days later, and the distribution and terminal morphology returning to almost normal at around 14 days. During regeneration, some regenerating Ruffini endings expressed neuropeptide Y, which is rarely observed in normal animals. On the other hand, the periodontal Ruffini endings show stage-specific configurations which are closely related to tooth eruption and the addition of occlusal forces to the tooth during postnatal development, suggesting that mechanical stimuli due to tooth eruption and occlusion are a prerequisite for the differentiation and maturation of the periodontal Ruffini endings. Further investigations are needed to clarify the involvement of growth factors in the molecular mechanisms of the development and regeneration processes of the Ruffini endings.
Chewing Gum—Facts and Fiction: a Review of Gum-Chewing and Oral Health
Authors: Imfeld T.
Published: January 2009

The world market for chewing gum is estimated to be 560,000 tons per year, representing approximately US $5 billion. Some 374 billion pieces of chewing gum are sold worldwide every year, representing 187 billion hours of gum-chewing if each piece of gum is chewed for 30 minutes. Chewing gum can thus be expected to have an influence on oral health. The labeling of sugar-substituted chewing gum as "safe for teeth" or "tooth-friendly" has been proven beneficial to the informed consumer. Such claims are allowed for products having been shown in vivo not to depress plaque pH below 5.7, neither during nor for 30 minutes after the consumption. However, various chewing gum manufacturers have recently begun to make distinct health promotion claims, suggesting, e.g., reparative action or substitution for mechanical hygiene. The aim of this critical review-covering the effects of the physical properties of chewing gum and those of different ingredients both of conventional and of functional chewing gum-is to provide a set of guidelines for the interpretation of such claims and to assist oral health care professionals in counseling patients.
Proteinases in Developing Dental Enamel
Authors: Bartlett J.D. , Simmer J.P.
Published: January 2009

For almost three decades, proteinases have been known to reside within developing dental enamel. However, identification and characterization of these proteinases have been slow and difficult, because they are present in very small quantities and they are difficult to purify directly from the mineralizing enamel. Enamel matrix proteins such as amelogenin, ameloblastin, and enamelin are cleaved by proteinases soon after they are secreted, and their cleavage products accumulate in the deeper, more mature enamel layers, while the full-length proteins are observed only at the surface. These results suggest that proteinases are necessary for "activating" enamel proteins so the parent proteins and their cleavage products may perform different functions. A novel matrix metalloproteinase named enamelysin (MMP-20) was recently cloned from tooth tissues and was later shown to localize primarily within the most recently formed enamel. Furthermore, recombinant porcine enamelysin was demonstrated to cleave recombinant porcine amelogenin at virtually all of the sites that have previously been described in vivo. Therefore, enamelysin is at least one enzyme that may be important during early enamel development. As enamel development progresses to the later stages, a profound decrease in the enamel protein content is observed. Proteinases have traditionally been assumed to degrade the organic matrix prior to its removal from the enamel. Recently, a novel serine proteinase named enamel matrix serine proteinase-1 (EMSP1) was cloned from enamel organ epithelia. EMSP1 localizes primarily to the early maturation stage enamel and may, therefore, be involved in the degradation of proteins prior to their removal from the maturing enamel. Other, as yet unidentified, proteinases and proteinase inhibitors are almost certainly present within the forming enamel and await discovery.
Oxidative Injury and Inflammatory Periodontal Diseases : the Challenge of Anti-Oxidants to Free Radicals and Reactive Oxygen Species
Authors: Battino M. , Bullon P. , Wilson M. , Newman H.
Published: January 2009

In recent years, there has been a tremendous expansion in medical and dental research concerned with free radicals, reactive oxygen species, and anti-oxidant defense mechanisms. This review is intended to provide a critical, up-to-date summary of the field, with particular emphasis on its implications for the application of "anti-oxidant therapy" in periodontal disease. We have reviewed the nomenclature, mechanisms of actions, features, and sources of most common free radicals and reactive oxygen species, as well as analyzed the typical biological targets for oxidative damage. Based on a review of direct and indirect anti-oxidant host defenses, particularly in relation to the key role of polymorphonuclear neutrophils in periodontitis, we review current evidence for oxidative damage in chronic inflammatory periodontal disease, and the possible therapeutic effects of anti-oxidants in treating and/or preventing such pathology, with special attention to vitamin E and Co-enzyme Q.
Actions of Hedgehog Proteins on Skeletal Cells
Authors: Iwamoto M. , Enomoto-Iwamoto M. , Kurisu K.
Published: January 2009

Recent advances in developmental and molecular biology during embryogenesis and organogenesis have provided new insights into the mechanism of bone formation. Members of the hedgehog gene family were initially characterized as patterning factors in embryonic development, but recently they have been shown to regulate skeletal formation in vertebrates. The amino terminal fragment of Sonic hedgehog (Shh-N), which is an active domain of Shh, has the ability to induce ectopic cartilage and bone formation in vivo. Shh-N stimulates chondrogenic differentiation in cultures of chondrogenic cell line cells in vitro and inhibits chondrogenesis in primary limb bud cells. These findings suggest that the regulation of chondrogenesis by hedgehog proteins depends on the cell populations being studied. Indian hedgehog (Ihh) is prominently expressed in developing cartilage. Ectopic expression of Ihh decreases type X collagen expression and induces the up-regulation of parathyroid hormone-related peptide (PTHrp) gene expression in perichondrium cells. A negative feedback loop consisting of Ihh and PTHrp, induced by Ihh, appears to regulate the rate of chondrocyte maturation. The direct actions of Shh and Ihh on stimulation of osteoblast differentiation are evidenced by the findings that these factors stimulate alkaline phosphatase activity in cultures of pluripotent mesenchymal cell line cells and osteoblastic cells and that these cells express putative receptors of hedgehog proteins. In conclusion, hedgehog proteins seem to be significantly involved in skeletal formation through multiple actions on chondrogenic mesenchymal cells, chondrocytes, and osteogenic cells.
Successful Aging From the Perspective of Family Caregivers
Authors: Hilton Jeanne M. , Kopera-Frye Karen , Krave Anne
Published: January 2009

Most models of successful aging have been limited to what researchers perceived to be its domains of rather than what elderly individuals and their caregivers have to say about their experiences. Sixty-five family caregivers recruited through geriatric care management agencies and support groups were interviewed to determine whether successful aging models accurately reflected their perspectives on aging. An open-ended question about successful aging was used along with a list of its 20 common characteristics, as identified in the literature, to compare the relevance of domains associated with different successful aging models. Caregivers identified domains in all major models, but new domains also emerged (e.g., quality of life, positive attitude, financial well-being). It was concluded that current models of successful aging may need to be expanded to include these additional domains and that quality of life may be a more inclusive and useful indicator of well-being than the concept of successful aging.
The Relationship Among Self-Report and Measured Report of Psychological Abuse, and Depression for a Sample of Women Involved in Intimate Relationships With Male Partners
Authors: Kelly Virginia , Warner Kelly , Trahan Courtenay , Miscavage Karen
Published: January 2009

This study examined the relationship between level of depression and level of psychological abuse in women. In addition, the relationship between the use of self-report and measured report of psychological abuse within an intimate relationship was assessed. One hundred women were surveyed using the Psychological Maltreatment of Women Inventory (PMWI) and the Beck Depression Inventory (BDI). Results form the PMWI, the BDI and self-report measures were compared and analyzed. Statistical results indicated that a significant relationship existed between level of depression and level of psychological abuse. In addition, self-report was not predictive of psychological abuse as measured by the PMWI.
Counseling African American Women: Let's Talk About Sex!
Authors: Thomas Chippewa M. , Crook Tylon M. , Cobia Debra C.
Published: January 2009

In the absence of clear, specific literature, this article provides information about the sexuality of African American women and identifies culturally relevant practices counselors may use to gain understanding of and respond to sex-related issues (i.e., development, identity, and activity) of African American women. Implications for counselors and recommendations for broaching sexual matters are discussed.
Counseling Suicidal Adolescents Within Family Systems: Ethical Issues
Authors: Berg Rachelle , Hendricks Bret , Bradley Loretta
Published: January 2009

Major ethical considerations must be taken into account when providing counseling services to suicidal adolescents and their families. This article explores these ethical issues and the American Counseling Association and International Association of Marriage and Family Counselors ethical codes relevant to these issues. Related liability and malpractice information is also discussed, including how counselors can follow professionally accepted standards of care and what must be done to improve client care and decrease the chances of a lawsuit.
Competencies in physical education teaching: Slovenian teachers' views and future perspectives
Authors: Kovač Marjeta , Sloan Stephen , Starc Gregor
Published: January 2009

This paper examines Slovenian physical education (PE) teachers' ( n = 85) estimations of their own actual and desired professional competencies with the aim of diagnosing the main needs of practising PE teachers and resolving them within a revised Slovenian Physical Education Teacher Education (PETE) curricula and through continued professional development programmes. Results show that PE teachers realistically acknowledge their own deficiencies within certain areas of practice, that during their training they are required to develop knowledge that is not directly applicable in PE classes, thus further detracting from the development of more relevant practically orientated knowledge, and that the reorganization of the Slovenian educational system during the last 15 years presented widespread demands that were not accompanied by appropriate professional institutional support. Their relative disinterest in the competencies developed through the subdisciplinary studies indicates that the mode and contents of the subdisciplinary subjects in the present PETE curriculum should be reviewed and refocused on the contents of the revised primary and secondary school curricula.
Pleasure and pain: Experiences of fitness testing
Authors: Wrench Alison , Garrett Robyne
Published: January 2009

The obesity crisis is a hegemonic discourse that has established common-sense understandings that young people are less active and fit than previous generations. Unquestioning acceptance of links between fitness and obesity in turn leads to unproblematic fitness testing of young people. Argument is made that fitness tests motivate and encourage participation in physical activity. Poststructural perspectives as informed by the work of Michel Foucault invite consideration of alternative possibilities around complex social phenomena such as the obesity crisis and pedagogical practices such as fitness testing. This research was informed by concerns about the unproblematic fitness testing of young people and calls for pedagogies of physical education that work to unsettle dominant discourses. The research investigates the experience of fitness testing from the perspective of university students pursuing health and physical education pathways through their degree programmes. Experiences of fitness testing were explored and the meanings made around participation, performances and results were interrogated.
A qualitative investigation into the characteristics and effects of music accompanying exercise
Authors: Priest David-Lee , Karageorghis Costas I.
Published: January 2009

The purpose of the present study was to identify the characteristics of music used to accompany physical exercise and investigate the effects of such music using a qualitative approach. This work underpins the further development of a theoretical structure that is still relatively new. Semi-structured interviews were conducted with a sample of exercise participants ( N = 13), seven males and six females, all with at least two years' experience of exercising to music. An inductive content analysis of the interview data was undertaken and results contrasted with the conceptual model developed by Karageorghis et al. (1999) which describes the effects of musical and cultural factors with reference to psychophysical outcomes. The findings demonstrated the importance of musical (e.g. rhythm, lyrics, bass), contextual (e.g. time of day) and individual factors (e.g. background, personality) in determining both short-term (e.g. mood, imagery) and long-term (e.g. heightened work-rate, endurance) outcomes. The findings point towards a more expansive conceptual framework. In particular, facets of the response to music such as flow state, cognitive responses, rhythm response and anticipation are discussed. Music perceived to be motivating could lead to increases in exercise intensity and endurance during performance of self-regulated tasks. These findings have implications for the use of music in physical education settings.