Ivan’s group focuses on periodontology and surgical implant dentistry, particularly in relation to improved clinical understanding and treatment outcomes. The team works closely with the Centre for Oral Health to understand the microbial and immunological of the pathogenesis of periodontal disease as well undertaking research based in private specialist practices. The group has a longstanding collaboration with Dr Lau in the Department of General Practice, Melbourne Medical School.
Microbiome profile of non-responding periodontal pockets after non-surgical periodontal treatment
The aims of this project are to gain a better understanding of the polymicrobial cause of chronic periodontitis, by describing the microbial community profile associated with non-responsive periodontal pockets after treatment, to compare the microbiome profile between non-responsive and responsive periodontal pockets and to compare the microbiome profile between responsive periodontal pockets with healthy sites
Metabolomic, Microbiomic and Genomic assessment of Periodontal Diseases.
The aim of this project is to document the associations between gum (periodontal) diseases and changes in clinical measurements, the bacteria, substances that the bacteria and body produce and the patient’s genetics. The key questions are: Do the bacteria associated with gum disease alter in relation to patient genetics, changes in the chemicals that the patient makes or the chemicals made by other bacteria within the plaque build up on teeth, Are there genes that make it more likely that someone will get gum disease, How do the changes in what the chemicals that the body makes relate to virulence of the bacteria and how the bacteria interact?
Dimensional changes in the alveolar ridge following tooth extraction and implant placement
Following tooth extraction the alveolar ridge undergoes both horizontal and vertical resorption during healing. Replacement of the tooth by an implant with concomitant contour augmentation is the current treatment paradigm. The first part of this project is a retrospective assessment of patient clinical records who have undergone dental implant surgery and had follow-up three dimensional (3D) x-ray taken at a private specialist dental practice. This allows for accurate measurements of the thickness and differences of the overlying hard and soft tissues above the dental implant and the corresponding natural tooth. These measurements, when correlated to the clinical records, allow for the evaluation of current techniques to match the natural ridge (bone and gum of jaw) architecture and how they impact the overall success of functional dental implants in the aesthetic region. The second part is to use intra-oral scanning for sequential 3D modelling following tooth extraction and implant placement to investigate the dimensional changes during healing and effect of grafting.
This project aims improve the interdisciplinary management of diabetes and periodontal disease. Previous research has piloted and evaluated the efficacy of the developed diabetes oral health educational program for health professionals, namely general medical practitioners (GPs), primary health care nurses including diabetes educators (PHCNs), community pharmacists (CPs) and oral health practitioners (OHPs).The next step is to develop a model of shared responsibility in diabetes management that involves General Practitioners (GPs), primary health care nurses (PNs) and oral health professionals (OHPs) in a community health setting. Our objective is to have a model and a training program for GPs, PNs and OHPs at end of the project in readiness for testing effectiveness (training program), feasibility and acceptability (model). We also aim to develop a necessary education and training workshop for GPs, PNs and OHPs on the shared diabetes care model.
Biologic and aesthetic outcomes three years post anterior implant placement with contour augmentation at sites with facial bone wall defects
Single-unit tooth implant restorations are routinely used in clinical dental practice. Whilst survival rates of single tooth implants have been extensively analysed, aesthetic evaluations are an emerging field of interest and follows patients’ increasing expectations regarding implant aesthetic outcomes. Current literature suggests that both soft-tissue changes around the implant site and crown characteristics are the primary aesthetic variables of interest; however, most investigations have only explored these variables in the short-term.In addition, the surgical sites of anterior implant placement are commonly compromised by defects in the facial (front side) bone. It has become common practice that grafting procedures, such as contour augmentation, are performed in order to rebuild and bolster the facial bone. The first part of this project aims to determine whether the condition of the facial bone wall at implant placement with concurrent contour augmentation influences biologic and aesthetic outcomes three years post implant placement. This will allow for the evaluation of current implant techniques in regards to the repair of facial bone wall defects and the aesthetic outcomes three years after treatment. The second part analyses 3-year data investigating soft-tissue changes and their subsequent influence on overall aesthetic outcomes.
Healing and management of extraction sockets
The aim of these studies is to evaluate the relationship between defects of the buccal bone wall at the time of extraction and the pattern of bone resorption after 8 weeks in maxillary central and lateral incisor sockets as well as to evaluate the efficacy of alveolar ridge preservation at maxillary central incisor extraction sockets that were grafted with a commercially available bone substitute.
Dr Alen Rahulan, DCD postgraduate student
Dr Theo Pang, DCD postgraduate student
Dr Patrick Bowman, DCD postgraduate student
Dr Richie Harvey, DCD postgraduate student
Dr Jean Lim, DCD postgraduate student
Dr Clarence Da Cruz, DCD postgraduate student
Dr Ahmed El Hadidi, DCD postgraduate student
Dental Anthropology Group
The effects of life events and population ancestry on teeth and the craniofacial skeleton are the main research focus of this group. Research is conducted by an interdisciplinary group of anatomists, dental and biological anthropologists, clinical dentists and specialists and earth scientists. We focus on evidence of diet and disease in mineralised tissues, changes in mineralised tissue features caused by trauma, disease and other life events, as well as ancestry traits in dental and craniofacial morphology.
Techniques employed include microCT, enamel isotope investigations, nanoCT, cranio- and odontometrics, TOF-SIMS and microscopy.
Life History in Dental Microstructure
This project proposes a highly innovative analytical technique for establishing life history parameters of mineralisation of tooth cementum increments, within the context of larger human populations through time. The aims of the project are: 1. To determine life history parameters, such as life-expectancy and ageing profiles of a medieval population in the Dici necropolis, Serbia. 2. To use isotopic analyses with Bayesian time-series modelling to test existing assumptions concerning life history parameters derived from cemetery data, integrating radiocarbon (δ14C) with δ¹³C and δ¹⁵N isotope results obtained from targeted individuals in the Dici necropolis.
The project’s objective is to develop a powerful new tool for life history researchers across disciplines.
Primary Investigator: Dr Marija Edinborough
Keeping up with dental development
Our group is interested in the timing of dental development. How this development differs in population groups all over the world, and how the timing of dentition development has changed over time has an effect on estimating the age of unknown human remains, both from an archaeological and forensic perspective. This new project will determine the accuracy of current dental development age estimation, and aims to develop updated standards for an Australian context. This project is available at PhD level.
Primary Investigator/Supervisor: Dr Sophie Beckett, Cranfield Forensics Institute (Honorary Fellow, Melbourne Dental School)
Co-investigator/Supervisor: Dr Rita Hardiman
Marvellous Melbourne Dental Health, Disease and Lifestyles
This project involves a multi-disciplinary research approach to investigate aspects of health, disease and lifestyle of Melburnians in the period from c. 1880-1930. Based on a collection of extracted teeth from an archaeological dig find, it involves studying the dental morphology, structure of teeth and any dental treatment, as well as physical indicators of daily activities (tobacco smoking, teeth as implements or tools). This program of research is in its initial stages, and aspects of the research are available as Honours, Masters or PhD projects.
Dental Calculus, Diet and Life Activity.
This project involves the investigation of microscopic inclusions in modern calculus samples, and how they relate to an individual’s diet. Ancient calculus samples are investigated to find micro-inclusions or microfossils, the presence of which are used to indicate diet and feeding practices. This study aims to investigate the relationship between the micro-inclusion evidence of diet in calculus samples and an individual’s normal diet. This project is available at Masters level.
Primary Investigator/Supervisor: Dr Rita Hardiman
Co-Investigator/Supervisor: Prof. Ivan Darby
Ms Angela Goh (PhD student)
Dr. Jacky Healy
Melbourne Femur Research Collection Group
The Melbourne Femur Research Collection group focuses on research in bone biology from a medical, fundamental science and anthropological perspective. The collection comprises over 600 items, including samples of femoral bone, CT/microCT/PQCT scans, microradiographs and associated data.Currently, the collection supports a diverse range of research projects internationally. To learn more about the collection and how to access it, please visit our online Melbourne Femur Research Collection.
Bone metabolism and lifestyle in modern Australian bone from forensic contexts.
This project aims to collect and analyse quantitative histology data from modern Australian human femur microradiographs. These data will be used to 1) reconstruct bone remodelling relationships to categories of lifestyle, and 2) compare with bone remodelling data from medieval English individuals (who derive from an osteological collection curated at the University of Kent, UK). This project tests whether bone remodelling has slowed down with lifestyle change over the course of our recent history, and how bone in modern Australians responds to different lifestyle factors. The final step will be then to use these findings in explaining bone health trends in various archaeological Asia-Pacific populations. Preliminary results suggest the MFRC samples to have developed with lower biomechanical input and experienced less remodelling than the medieval samples. This project is part of an ARC DECRA (2019-2022) awarded to Dr Justyna Miszkiewicz at the ANU, and also involves a collaboration with researchers at the University of Kent, UK; and The George Institute for Global Health in Sydney.
Primary Investigator: Dr Justyna Miszkiewicz, Australian National University
Collaborators: Dr Rita Hardiman.
Sex determination in unknown human remains using dimorphism in femoral head volume.
Sex determination is an important aspect of identifying unknown human remains. Studies on skeletal collections have shown that femoral head diameter may be a useful determinant of sex in humans. This project involves developing a technique to define landmarks and develop volumetric measurement of the human femoral head. The results will then be used to test whether this is an effective method of determining an individual’s sex. This project is available at Masters level.
Primary Investigator/Supervisor: Dr Rita Hardiman
What is the origin of tetracycline-like staining in a sample of contemporary human femoral cortical bone?
The Melbourne Femur Research Collection is a well-documented sample of modern femoral bones. A number of years ago, research into the collection brought up a serendipitous finding of fluorescent staining in quite a high proportion of the collection. The staining, which was found in 73% of bones investigated, is characteristic of tetracycline compounds. The extent and severity of the staining raised a number of questions as to its origin and cause. Tetracycline is a broad-spectrum antibiotic, but is not recommended for use in those under eight years of age. This is because tetracycline accumulates in the mineralising regions of bones and teeth, and use in those under eight years of age can lead to visible discoloration of teeth.
This project will involve investigative techniques such as mass spectrometry to determine the exact cause of the fluorescence (thought to be tetracycline) within the bone tissue of the Melbourne Femur Research Collection, and will aim to determine the origin of the substance incorporated into the growing bone tissue.
There are many questions still to be answered about this finding: Is the staining actually caused by tetracycline? If it is tetracycline, what is the origin- therapeutic, or some other source? Is this result unique in this collection, or does it exist in other skeletal collections in Australia or the rest of the world?
This project is available at Masters level.
Primary Investigator/Supervisor: Dr Rita Hardiman
Co-supervisor/Investigator: Dr Louise Shewan
Oral Inflammation & Innate Immunity Group
Our group’s major objective is to understand how host‒microbe homeostasis in the oral cavity is maintained. This is important because the disruption of homeostasis causes various oral inflammatory diseases (e.g. periodontitis) as well as exacerbates systemic inflammatory diseases. Thus, we want to understand the mechanisms that enable the innate immune system to maintain immunological homeostasis with commensal bacteria whilst preventing infection by pathogens. We employ a range of experimental systems in our research, including genetically-modified mice, coupled with cell culture systems. This is complemented by various technologies and experimental approaches, including gene expression profiling, cell signalling pathway analysis, mass spectrometry-based proteomics, and cell imaging.
Understanding how oral mucosal epithelial cells tailor different immune responses to commensal bacteria and pathogens
Oral mucosal epithelial cells express innate immune receptors that enable the detection of bacteria. However, how these cells tolerate commensal bacteria and yet stimulate inflammation in response to pathogens is poorly understood. Our latest research indicates the spatial context in which bacteria are detected by epithelial cells within the oral mucosa plays a critical instructive role in enabling the cells to discriminate between commensal bacteria and pathogens and thereby respond appropriately. You will build on this novel research by investigating how spatiotemporal regulation of mucosal inflammatory pathways could enable differentially-tailored immune responses to commensal bacteria and pathogens.
Deciphering an epithelial cell intrinsic TLR2‒IL 36γ axis in oral mucosal immunity and homeostasis
The oral cavity is a major entry portal for many important bacterial pathogens. Our latest research indicates the innate immune receptor TLR2 and the novel inflammatory cytokine Interleukin 36 gamma (IL 36γ) function as an epithelial cell intrinsic axis to orchestrate the host response to bacteria; for example, regulating expression of cytokines that recruit specific immune cell subsets (e.g. T helper cells). Using gene knockout mice and cell culture systems, you will build on this novel research and elucidate how the TLR2‒IL 36γ axis orchestrates oral mucosal immunity to maintain host‒microbe homeostasis.
How the IRF6 transcription factor regulates oral mucosal immunity and homeostasis
We have previously established that IRF6 directly regulates specific Toll-like receptor-mediated host defence functions of oral epithelial cells by regulating the expression of inflammatory genes. Our latest research indicates IRF6 also indirectly regulates their host defence functions via its control of epithelial cell terminal differentiation. This is important because our latest research indicates that epithelial differentiation may enable spatiotemporal control of immune responses to bacteria in the oral mucosa. You will build on this novel research by elucidating how IRF6 enables spatiotemporal regulation of oral mucosal inflammatory pathways.
Elucidating how bacterial metabolites can disrupt host-microbe homeostasis in the oral mucosa
The innate immune system is activated by structural components of bacteria (e.g. lipopeptides). However, bacterial metabolic products, such as short-chain fatty acids (SCFA), have emerged as important modulators of innate immune cell activation via both epigenetic and non-epigenetic mechanisms. We have found that SCFA also modulate specific host defence functions of oral mucosal epithelial cells. This is important because it may help to explain how dysbiosis disrupts host microbe homeostasis and promotes inflammation in the oral mucosa. You will build on this novel research by investigating the mechanisms underlying the effects of bacterial SCFA on oral mucosal epithelial cell host defence functions.
The Oral Microbiology and Microbiome Group
The Oral Microbiology and Microbiome Group is part of the Centre for Oral Health Research at the Melbourne Dental School. We use systems biology approaches to determine the causes of chronic human diseases and conditions that involve oral microorganisms. In particular we are applying a range of microbiomic approaches to determine the aetiology of polymicrobial diseases that result from dysbiosis. The long-term aim of all of these studies is to develop novel strategies for the prevention and treatment of human disease.
Early Childhood Caries
Early Childhood Caries affects the majority of children in Victoria and in severe cases can have a significant detrimental effect on development and quality of life. Early Childhood Caries is a preventive disease yet is the leading reason for preventable childhood hospitalisations. In these studies we take multidisciplinary approaches to understanding the causes, progression, prevalence, severity and natural history of disease. We also examine the current preventive treatments for early childhood caries in Victoria and their effectiveness. These projects bring together microbiology, epidemiology, biostatistics, biomarker discovery and a range of innovative approaches that will translate to better health.
An oral bacterial aetiology for Alzheimer's Disease.
As it is becoming more apparent that bacteria or their products are able to cross the blood brain barrier we are determining the role of oral bacteria in the development and progression of Alzheimer's Disease. Our aims are to understand how bacteria escape from the oral cavity, colonise the brain and how they influence the progression of disease.
Bacterial chemotaxis and chronic disease
Treponema denticola is a chemotactic, motile spirochaete that is an aetiological agent of chronic periodontitis. Its unique form of motility and chemotaxis enable it to move through highly viscous environments. It has twenty chemoreceptor proteins that enable it to respond to a range of stimulatory substances. In this project we will determine how T. denticola responses to environmental stimuli and how this affects its ability to form pathogenic polymicrobial biofilms. We are cloning and expressing T. denticola chemotaxis proteins and determining their substrate specificity using highly novel microarray technologies. Using specific T. denticola mutants we will characterise polymicrobial biofilm development using a custom-built flow cell and confocal scanning laser microscopy.
The role of microbial dysbiosis in chronic oral diseases
The aims of this group of related projects are to gain a better understanding of the polymicrobial cause of chronic oral diseases including periodontitis and dental caries using microbiomic approaches. In collaboration with our clinical researchers we determine the microbiomes of human clinical samples and relate these bacterial communities to the disease state. These diseases are caused by a dysbiosis in the oral bacterial communities that leads to the emergence of a group of pathobionts that dominate the community.
Polymicrobial interactions in disease
The majority of human chronic diseases result from the interactions of groups of bacteria that result in a pathogenic community. We use multidisciplinary approaches that include polymicrobial culture, molecular biology, recombinant protein expression, genomics, microbiomics, transcriptomics and proteomics to describe how interactions between bacterial species are linked to disease.