Identification Of Porphyromonas Gingivalis Genes Required For Iron/haem Acquisition And Biofilm Formation
Funder
National Health and Medical Research Council
Funding Amount
$476,836.00
Summary
Periodontal diseases are some of the most common bacterial diseases of humans and along with dental caries, account for approximately 90% of all tooth loss in the Australian population. A recent survey of oral health in Australia found that in the 30-34 age group over 20% of people had moderate to severe periodontal disease, indicating that periodontitis is a major public health problem. Specific bacteria, especially Porphyromonas gingivalis, that grow as bacterial biofilms (dental plaque) cause ....Periodontal diseases are some of the most common bacterial diseases of humans and along with dental caries, account for approximately 90% of all tooth loss in the Australian population. A recent survey of oral health in Australia found that in the 30-34 age group over 20% of people had moderate to severe periodontal disease, indicating that periodontitis is a major public health problem. Specific bacteria, especially Porphyromonas gingivalis, that grow as bacterial biofilms (dental plaque) cause periodontal disease. In this study we will utilise the latest technology available to determine which genes of the bacterium are important for biofilm growth, iron acquisition and virulence in an animal model. We will investigate how the bacterium acquires iron, as there is usually little available iron for bacterial growth on human tissues and the ability of the bacterium to free itself from this iron limitation is associated with pathogenicity. The determination of the role of iron availability in biofilm formation and virulence of the bacterium will help us to understand the changes that occur in the initiation of disease and may allow the development of early intervention strategies. The significance of this work is that we will gain an understanding of how this bacterium functions as an opportunistic human pathogen. We will determine which genes are essential for growth as a biofilm and to produce disease in an animal model. This will enable the development of therapeutic and prophylactic interventions targeted to specific bacterial gene products required to produce disease.Read moreRead less
The National Survey of Adult Oral Health will interview and dentally examine 7,500 people aged 15 or more across all States and Territories of Australia. It will provide a national snap-shot of the nation's oral health, including levels of tooth loss, dental decay and gum disease. The survey, to be conducted in 2004-04, will be directed by researchers at the Australian Research Center for Population Oral Health at The University of Adelaide. It will be conducted in collaboration with the Commonw ....The National Survey of Adult Oral Health will interview and dentally examine 7,500 people aged 15 or more across all States and Territories of Australia. It will provide a national snap-shot of the nation's oral health, including levels of tooth loss, dental decay and gum disease. The survey, to be conducted in 2004-04, will be directed by researchers at the Australian Research Center for Population Oral Health at The University of Adelaide. It will be conducted in collaboration with the Commonwealth and State-Territory health departments. Occurring 17 years after the first National Oral Health Survey of Australia, this new survey will monitor changes in oral health among all Australians. The survey will identify groups at particular disadvantage in terms of oral diseases, and it will search for lifestyle and community-level hazards that increase the risk of oral disorders. The study will have a compare patterns of dental health among people born before and after the fluoride generation of adults born in the 1960s when most of Australia's capital city water supplies became fluoridated. The study has been designed to automatically capture national statistics on general health among the 7,500 study participants over the next decade. The researchers will use that information to study links that have been observed in other countries between gum disease and heart disease. Results from the survey will provide the basis for monitoring progress towards national health targets and provide information to help direct dental health services into the 21st century.Read moreRead less
The Impact Of Declining Tooth Loss On Oral Health Status And Dental Care Utilisation
Funder
National Health and Medical Research Council
Funding Amount
$144,375.00
Summary
Improved oral health has been well documented in Australia. Over recent decades the average number of decayed teeth among children has decreased. Among adults, the percentage with no natural teeth has also exhibited a decrease over time. While increased retention of natural teeth is an indicator of improved oral health status within the population, there may be some unexpected consequences of this success. Improved oral health has been associated with increased rather then decreased use of servi ....Improved oral health has been well documented in Australia. Over recent decades the average number of decayed teeth among children has decreased. Among adults, the percentage with no natural teeth has also exhibited a decrease over time. While increased retention of natural teeth is an indicator of improved oral health status within the population, there may be some unexpected consequences of this success. Improved oral health has been associated with increased rather then decreased use of services. Improvements in oral health manifested in the form of greater tooth retention, coupled with demographic trends towards growth in the population, may lead to an increased risk of oral disease with flow on effects on need and demand for care. Findings from one cross-sectional study in the USA have shown that people who retained higher numbers of teeth had more periodontal disease and dental caries experience, and reported a past pattern of visiting the dentist more frequently. The specific aims of this project are to examine the association of the number of natural teeth among middle-aged Australians with their oral health status, treatment needs and subsequent use of dental services. The outcome of this project will provide answers to two research questions. Firstly, it will see whether the retention of more teeth among adults is associated with higher levels of oral disease. Secondly, by following people over time it will be able to detect whether those who are retaining more teeth into adult age ranges have higher levels of use of dental services than their counterparts with fewer teeth. The answers to both of these research questions has significance for policy and planning in the area of dental public health by providing evidence as to the size and direction of expected future demand for and use of dental services in Australia.Read moreRead less
Tooth wear is a significant clinical problem for both older people who have kept their natural teeth and for some younger individuals. The main causes of tooth wear are attrition (resulting from tooth to tooth contact), abrasion (from dietary and environmental abrasives) and erosion (caused by acidic food and drinks or from regurgitation of acid). At present our understanding of the relative significance of these types of wear and the exact conditions under which excessive wear occurs is limited ....Tooth wear is a significant clinical problem for both older people who have kept their natural teeth and for some younger individuals. The main causes of tooth wear are attrition (resulting from tooth to tooth contact), abrasion (from dietary and environmental abrasives) and erosion (caused by acidic food and drinks or from regurgitation of acid). At present our understanding of the relative significance of these types of wear and the exact conditions under which excessive wear occurs is limited. Furthermore our understanding of the wear characteristics of many commonly used dental materials is limited. The proposed study will provide important new information about: the interaction between applied bite forces and acids in the oral environment as determinants of the rate of tooth wear; the potential for wear prevention using mouth rinses and gels; the wear characteristics of dental materials commonly used to restore teeth.Read moreRead less
Molecular Studies Of Dentine Phosphophoryn And Development Of A Biomimetic Dental Restorative Material.
Funder
National Health and Medical Research Council
Funding Amount
$444,750.00
Summary
This project involves the study of a protein that is found in teeth and is responsible for the development of dentine. The project involves characterisation of this protein and its interaction with calcium phosphate mineral using a variety of techniques. The information obtained will allow the synthesis of a peptide that will mimick the function of phosphophoryn. This peptide will be used together with stabilized amorphous calcium phosphate in a novel dental restorative material that will help p ....This project involves the study of a protein that is found in teeth and is responsible for the development of dentine. The project involves characterisation of this protein and its interaction with calcium phosphate mineral using a variety of techniques. The information obtained will allow the synthesis of a peptide that will mimick the function of phosphophoryn. This peptide will be used together with stabilized amorphous calcium phosphate in a novel dental restorative material that will help protect the surrounding tooth tissue.The outcome will be an improved understanding of the design principles used by nature to engineer teeth. The significance is the potential development of biocompatible, superior dental restorative materials.Read moreRead less
Characterisation Of Proteins Involved In Biomineralisation Processes
Funder
National Health and Medical Research Council
Funding Amount
$234,175.00
Summary
This project involves the study of two proteins that associate with calcium and phosphate. Phosphophoryn is found in teeth and is responsible for the development of dentine in teeth. Osteopontin is a multi-functional protein found in a variety of tissues as well as in bone and in milk. Its functions in bone and milk are unknown although it is believed to be involved in bone remodelling. This project involves characterisation of these two proteins and their interactions with calcium phosphate min ....This project involves the study of two proteins that associate with calcium and phosphate. Phosphophoryn is found in teeth and is responsible for the development of dentine in teeth. Osteopontin is a multi-functional protein found in a variety of tissues as well as in bone and in milk. Its functions in bone and milk are unknown although it is believed to be involved in bone remodelling. This project involves characterisation of these two proteins and their interactions with calcium phosphate mineral using a variety of techniques. The outcome will be an improved understanding of the design principles used by nature to engineer teeth and bone. The significance is the potential development of biocompatible apatite-based biomaterials for both tooth and bone.Read moreRead less
Reflex Control Of Human Jaw Muscles By Periodontal Mechanoreceptors
Funder
National Health and Medical Research Council
Funding Amount
$405,173.00
Summary
An understanding of the functional connection between the jaw muscles and various receptor organs in and around the mouth is necessary to elucidate the process of chewing and its underlying rules. Unless the details of this functional connection in health and disease are thoroughly understood, the diagnosis and treatment of chewing related disorders will remain at the present state. For example: a We still do not know why chewing in edentulous subjects is less efficient and why the bite forces i ....An understanding of the functional connection between the jaw muscles and various receptor organs in and around the mouth is necessary to elucidate the process of chewing and its underlying rules. Unless the details of this functional connection in health and disease are thoroughly understood, the diagnosis and treatment of chewing related disorders will remain at the present state. For example: a We still do not know why chewing in edentulous subjects is less efficient and why the bite forces in these individuals immediately fall to about 20 % of the teethed value. Do jaw muscles in these subjects get weak because they get less support from the receptor organs around the teeth? a We still do not understand the cause-causes of the temporomandibular dysfunction (a painful disease involving jaw muscles) which forms 18.7 % of total dental patients consulted per week in South Australia. This South Australian study indicated that the current treatments (such as pain killers, night plates, massage) Ocures? only about the half of all patients. We cannot increase the success of the treatment if we do not fully understand the control mechanisms of chewing? It is expected that the results of this study will establish the functional connection between one of the most important receptor organs in the mouth (periodontal mechanoreceptors) to the jaw muscle motoneurons in subjects with healthy teeth and gums and will illustrate the importance of keeping the periodontium healthy for developing strong and smooth masticatory forces. This knowledge can also allow us to treat jaw related disorders by approaches that bring back normal operation of the system. For example, this knowledge may help us design active dentures that replace the missing support.Read moreRead less
Control Of Mastication By Periodontal Mechanoreceptors In Man
Funder
National Health and Medical Research Council
Funding Amount
$169,990.00
Summary
Despite the importance in chewing and speech, very little is known regarding the fine control of jaw muscles. A thorough understanding of the control of the jaw muscles is at the base of improved diagnosis and treatment of many chewing disorders. For example: We still do not understand the causes of the jaw muscle-joint pain disorder (temporomandibular dysfunction) which accounts for about 5 % of total dental patients. The current treatments, including pain killers, night plates and massage cure ....Despite the importance in chewing and speech, very little is known regarding the fine control of jaw muscles. A thorough understanding of the control of the jaw muscles is at the base of improved diagnosis and treatment of many chewing disorders. For example: We still do not understand the causes of the jaw muscle-joint pain disorder (temporomandibular dysfunction) which accounts for about 5 % of total dental patients. The current treatments, including pain killers, night plates and massage cure only about half of all patients. Improved diagnosis and treatment techniques require more precise elaboration of the neural and muscular mechanisms of chewing. Why do the chewing forces in toothless individuals, despite well fitting dentures, fall to about 20 % of the value in teethed individuals? Do jaw muscles in these subjects weaken because they get less feedback from the receptors around the teeth? How does the chewing force automatically adjust to overcome sudden or gradual changes in the characteristics of foodstuff? Although bite to bite changes in the chewing force is observed in subjects with natural teeth, no such changes occur in toothless subjects or subjects chewing with implanted bridges. How do the receptors adjust the activation of jaw muscles so that bite force is applied in the right direction and right amount at each bite? The aim of this study is to define the importance of the periodontal mechanoreceptors (tiny nerve cells that are situated between the roots of the teeth and the jaw bone that signal bite force to the brain) in the control of jaw muscles. This study will, therefore, illustrate the importance of keeping the teeth and gums healthy for the development of strong, smooth and well-controlled chewing forces, and potentially create opportunities to improve chewing (and thereby quality of life) in toothless individuals or those experiencing other difficulties in chewing.Read moreRead less
After The Cloning Of The HMSNL Gene: Molecular Pathogenesis Of The Disease
Funder
National Health and Medical Research Council
Funding Amount
$258,564.00
Summary
We have completed an NHMRC-funded study, where we identified the gene for a severe disorder of the peripheral nervous system. The disease, hereditary motor and sensory neuropathy - Lom (HMSNL), presents with gait disturbances, difficulty in using the hands, muscle weakness and wasting and sensory loss. The concomitant impairment of the insulating myelin sheath surrounding nerve fibres (facilitating nerve conduction) and of the nerve fibres themselves suggests that the molecular defect lies in th ....We have completed an NHMRC-funded study, where we identified the gene for a severe disorder of the peripheral nervous system. The disease, hereditary motor and sensory neuropathy - Lom (HMSNL), presents with gait disturbances, difficulty in using the hands, muscle weakness and wasting and sensory loss. The concomitant impairment of the insulating myelin sheath surrounding nerve fibres (facilitating nerve conduction) and of the nerve fibres themselves suggests that the molecular defect lies in the basic mechanisms of interaction between the two main types of cell in the peripheral nervous system: the myelin-producing Schwann cell and the neuron. The two cells form the most complex system of communication in the human body, where signaling from one is vital for the development, functioning and survival of the other. Very little is known about the molecular mechanisms of this communication. At the same time, knowledge of the normal mechanisms of interaction is the key to better understanding of the mechanisms of disease in the peripheral nervous system and of the causes and possible prevention of the impairment of function. The newly identified HMSNL gene is probably involved in the signaling necessary for the development and functioning of the Schwann cell and for the survival of the nerve fibres. To gain an insight into the nature of the signaling cascade, we propose to use several complementary experimental approaches. We will create a mouse model of the human disease, to study its very early stages and subsequent evolution. In parallel, we will use molecular techniques and a yeast model, to identify other steps in the signaling cascade. The NHMRC-funded study will be part of a larger project conducted in collaboration with leading laboratories in the UK and the Netherlands, where other aspects of the molecular basis of the disease and of the role of the new gene will be examined.Read moreRead less
A Clinical And Experimental Study Of The Biomechanical Factors Associated With Tooth Destruction
Funder
National Health and Medical Research Council
Funding Amount
$241,527.00
Summary
This project investigates the influence of biting force on the development of non-carious and carious defects of teeth. Strain gauges will be cemented to the neck region of extracted teeth and teeth in the mouth, forces applied to the biting surfaces of the teeth, and the stress which results will be measured by the strain gauge. A profiling technique and high-power microscopy will be used to determine the amount of tooth structure lost as a result of applying the forces in the presence of acid. ....This project investigates the influence of biting force on the development of non-carious and carious defects of teeth. Strain gauges will be cemented to the neck region of extracted teeth and teeth in the mouth, forces applied to the biting surfaces of the teeth, and the stress which results will be measured by the strain gauge. A profiling technique and high-power microscopy will be used to determine the amount of tooth structure lost as a result of applying the forces in the presence of acid. In addition, a computer model will be generated, to determine whether it can be used to predict the stresses. In a clinical study, patients with and without non-carious defects will be followed for three years in order to assess the morphological changes and measure the volume loss of tooth structure which occurs.Read moreRead less