Melbourne Dental School - Research Publications
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ItemKimura's disease: an uncommon cause of head and neck masses with potentially serious sequelae(OXFORD UNIV PRESS, 2015-10-01)Kimura's disease (KD) typically presents as a mass in the head and neck region in association with eosinophilia and elevated serum IgE. Excisional biopsy is often required in order to obtain an adequate sample for histological diagnosis and exclude malignancy. If suspected, patients should also be investigated for renal involvement as this may complicate KD. Treatment options include surgical excision and medical therapies such as corticosteroids depending on the extent and severity of disease.
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ItemSleep quality and the treatment of intestinal microbiota imbalance in Chronic Fatigue Syndrome: A pilot study.(Georg Thieme Verlag KG, 2015-11)Chronic Fatigue Syndrome (CFS) is a multisystem illness, which may be associated with imbalances in gut microbiota. This study builds on recent evidence that sleep may be influenced by gut microbiota, by assessing whether changes to microbiota in a clinical population known to have both poor sleep and high rates of colonization with gram-positive faecal Streptococcus, can improve sleep. Twenty-one CFS participants completed a 22- day open label trial. Faecal microbiota analysis was performed at baseline and at the end of the trial. Participants were administered erythromycin 400 mg b.d. for 6 days. Actigraphy and questionnaires were used to monitor sleep, symptoms and mood. Changes in patients who showed a clinically significant change in faecal Streptococcus after treatment (responders; defined as post-therapy distribution<6%) were compared to participants who did not respond to treatment. In the seven responders, there was a significant increase in actigraphic total sleep time (p=0.028) from baseline to follow up, compared with non-responders. Improved vigour scores were associated with a lower Streptococcus count (ρ=-0.90, p=0.037). For both the responders and the whole group, poorer mood was associated with higher Lactobacillus. Short term antibiotic treatment appears to be insufficient to effect sustainable changes in the gut ecosystem in most CFS participants. Some improvement in objective sleep parameters and mood were found in participants with reduced levels of gram-positive gut microbiota after antibiotic treatment, which is encouraging. Further study of possible links between gut microorganisms and sleep and mood disturbances is warranted.
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ItemPrevalence of chronic periodontitis in an obese population: a preliminary study(BMC, 2015-09-29)BACKGROUND: Chronic periodontitis (CP) is a global public health issue. Studies have suggested CP could be linked to obesity due to their similar pathophysiological pathway. The aim of this study is to determine the prevalence of CP and to assess the predictors for CP among the obese Malaysian population. METHODS: This is a cross-sectional study on obese participants. Obesity is defined as an individual who has Body Mass Index (BMI) ≥ 27.5 kg/m(2). A convenience sampling method was used. A total of 165 paricipants were recruited. This study involved answering questionnaires, obtaining biometric and clinical measurements of Visible plaque index (VPI), Gingival bleeding index (GBI), Probing pocket depth (PPD) and Clinical attachment loss (CAL). Data analysis was carried out using SPSS statistical software (SPSS Inc., version 20, US). RESULTS: A total of 165 participants; 67 (40.6%) males and 98 (59.4%) females participated in the study. Mean age of the participants was 43.9 (± 8.9). The prevalence of CP among the obese population was found to be 73.9%. Out of this, 43 and 55% were categorised as moderate and severe CP respectively. Around 64% of participants had sites with CAL ≥ 4 mm and participants with sites with PPD ≥ 4 mm were reported to be 25%. Around 83% of the participants had sites with GBI ≥ 30 and 92% of participants had sites with VPI ≥ 20%. GBI and VPI were found to have significantly higher odds for CP. CONCLUSION: Prevalence of CP was high among obese Malaysians. GBI and VPI were potential predictors for CP in this obese population.
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ItemBayesian Modeling and Chronological Precision for Polynesian Settlement of Tonga(PUBLIC LIBRARY SCIENCE, 2015-03-23)First settlement of Polynesia, and population expansion throughout the ancestral Polynesian homeland are foundation events for global history. A precise chronology is paramount to informed archaeological interpretation of these events and their consequences. Recently applied chronometric hygiene protocols excluding radiocarbon dates on wood charcoal without species identification all but eliminates this chronology as it has been built for the Kingdom of Tonga, the initial islands to be settled in Polynesia. In this paper we re-examine and redevelop this chronology through application of Bayesian models to the questioned suite of radiocarbon dates, but also incorporating short-lived wood charcoal dates from archived samples and high precision U/Th dates on coral artifacts. These models provide generation level precision allowing us to track population migration from first Lapita occupation on the island of Tongatapu through Tonga's central and northern island groups. They further illustrate an exceptionally short duration for the initial colonizing Lapita phase and a somewhat abrupt transition to ancestral Polynesian society as it is currently defined.
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ItemThe micro-architecture of human cancellous bone from fracture neck of femur patients in relation to the structural integrity and fracture toughness of the tissue.(Elsevier BV, 2015-12)Osteoporosis is clinically assessed from bone mineral density measurements using dual energy X-ray absorption (DXA). However, these measurements do not always provide an accurate fracture prediction, arguably because DXA does not grapple with 'bone quality', which is a combined result of microarchitecture, texture, bone tissue properties, past loading history, material chemistry and bone physiology in reaction to disease. Studies addressing bone quality are comparatively few if one considers the potential importance of this factor. They suffer due to low number of human osteoporotic specimens, use of animal proxies and/or the lack of differentiation between confounding parameters such as gender and state of diseased bone. The present study considers bone samples donated from patients (n = 37) who suffered a femoral neck fracture and in this very well defined cohort we have produced in previous work fracture toughness measurements (FT) which quantify its ability to resist crack growth which reflects directly the structural integrity of the cancellous bone tissue. We investigated correlations between BV/TV and other microarchitectural parameters; we examined effects that may suggest differences in bone remodelling between males and females and compared the relationships with the FT properties. The data crucially has shown that TbTh, TbSp, SMI and TbN may provide a proxy or surrogate for BV/TV. Correlations between FT critical stress intensity values and microarchitecture parameters (BV/TV, BS/TV, TbN, BS/BV and SMI) for osteoporotic cancellous tissue were observed and are for the first time reported in this study. Overall, this study has not only highlighted that the fracture model based upon BMD could potentially be improved with inclusion of other microarchitecture parameters, but has also given us clear clues as to which of them are more influential in this role.
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ItemBone and Tooth Regeneration in Maxillofacial Region(HINDAWI LTD, 2015-01-01)
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ItemDental enamel cells express functional SOCE channels(NATURE PUBLISHING GROUP, 2015-10-30)Dental enamel formation requires large quantities of Ca(2+) yet the mechanisms mediating Ca(2+) dynamics in enamel cells are unclear. Store-operated Ca(2+) entry (SOCE) channels are important Ca(2+) influx mechanisms in many cells. SOCE involves release of Ca(2+) from intracellular pools followed by Ca(2+) entry. The best-characterized SOCE channels are the Ca(2+) release-activated Ca(2+) (CRAC) channels. As patients with mutations in the CRAC channel genes STIM1 and ORAI1 show abnormal enamel mineralization, we hypothesized that CRAC channels might be an important Ca(2+) uptake mechanism in enamel cells. Investigating primary murine enamel cells, we found that key components of CRAC channels (ORAI1, ORAI2, ORAI3, STIM1, STIM2) were expressed and most abundant during the maturation stage of enamel development. Furthermore, inositol 1,4,5-trisphosphate receptor (IP3R) but not ryanodine receptor (RyR) expression was high in enamel cells suggesting that IP3Rs are the main ER Ca(2+) release mechanism. Passive depletion of ER Ca(2+) stores with thapsigargin resulted in a significant raise in [Ca(2+)]i consistent with SOCE. In cells pre-treated with the CRAC channel blocker Synta-66 Ca(2+) entry was significantly inhibited. These data demonstrate that enamel cells have SOCE mediated by CRAC channels and implicate them as a mechanism for Ca(2+) uptake in enamel formation.
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ItemMidwives' perspectives of their ability to promote the oral health of pregnant women in Victoria, Australia(BMC, 2015-05-07)BACKGROUND: Midwives have a potential role in promoting the oral health of pregnant women although they have little formal training in this area. The aim of this study was to explore the perspectives of midwives in Victoria towards incorporating oral health promotion into their antenatal practice after undergoing training through the Midwifery Initiated Oral Health (MIOH) online education program. METHODS: A purposive sample of thirty-nine midwives from maternity services across Victoria, Australia were invited to participate in an online MIOH education program in October 2012. The program included three self-paced modules covering oral health screening, referral processes, and theoretical and practical skill assessments. A mixed methods design was used to capture midwives perspectives. Evaluation questionnaires, completed pre- and post-training, captured knowledge and confidence (confidence likert scale), and also included five opened-ended questions post-training. Open-ended questions, feedback forms and unsolicited emails formed the data for qualitative analysis. Data were analysed using content and thematic analysis and descriptive statistics. RESULTS: Thirty-three midwives completed the MIOH education program and demonstrated a significant increase (51.5%) in their confidence to promote oral health. All participants viewed the program as suitable, acceptable and useful for their practice and were happy to recommend the course to other Victorian midwives. Participants indicated that it would be feasible to incorporate oral health into the first antenatal booking visit and recognised that oral health promotion was within their scope of practice. CONCLUSIONS: This study has shown that the MIOH education program is a valued resource that can assist midwives to increase their confidence and skills to incorporate oral health promotion into their practice. A key barrier identified was time constraints during antenatal care booking visits. However, it is evident that with relevant training it would be feasible and acceptable for Victorian midwives to incorporate oral health promotion within their practice. The current engagement with midwives in Victoria and other parts of Australia provides an opportunity to continue to explore and define the role of antenatal health care professionals in oral health promotion at a state and national level.
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ItemEffect of prosthodontic planning on lateral occlusion scheme: a comparison between conventional and digital planning(UNIV SAO PAULO FAC ODONTOLOGIA BAURU, 2015-03-01)UNLABELLED: Recently, digital wax-up is proposed as a tool to aid prosthodontic planning. However, there are no data about the effect of prosthodontic planning on lateral occlusion scheme. OBJECTIVE: This study aims to evaluate the impact of conventional and digital prosthodontic planning on lateral occlusion scheme. MATERIAL AND METHODS: Dental models of 10 patients were collected. All models had Angle Class I occlusion and were undergoing prosthodontic treatment that would influence the lateral occlusion scheme. Each set of models had received both conventional wax-up and digital wax-up. In relation to the lateral occlusion scheme, the following variables were evaluated: the prevalence of the different lateral occlusion scheme, number of contacting teeth and percentage of each contacting tooth. Four excursive positions on the working side were included: 0.5, 1.0, 2.0 and 3.0 mm from the maximal intercuspation position. RESULTS: The lateral occlusion scheme of the two wax-up models was subjected to alterations following excursion. There was a tendency for the prevalence of canine-guided occlusion to increase and for the prevalence of group function occlusion to decrease with increasing excursion. The number of contacting teeth was decreasing with the increasing magnitude of excursion. For the 0.5 mm and 1.0 mm positions, the two wax-ups had significantly greater contacts than the pre-treatment models, while at the 2.0 mm and 3.0 mm positions, all the models were similar. For all models, canines were the most commonly contacting teeth, followed by the teeth adjacent to them. No difference was observed between the two wax-ups in relation to the number of contacting teeth. CONCLUSION: Although the prosthodontic planning had influenced the pattern of the lateral occlusion scheme and contacts, there was no difference between the conventional and digital prosthodontic planning.
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ItemLipotoxic Stress Induces Pancreatic beta-Cell Apoptosis through Modulation of Bcl-2 Proteins by the Ubiquitin-Proteasome System(HINDAWI LTD, 2015-01-01)Pancreatic β-cell loss induced by saturated free fatty acids (FFAs) is believed to contribute to type 2 diabetes. Previous studies have shown induction of endoplasmic reticulum (ER) stress, increased ubiquitinated proteins, and deregulation of the Bcl-2 family in the pancreas of type 2 diabetic patients. However, the precise mechanism of β-cell death remains unknown. In the present study we demonstrate that the FFA palmitate blocks the ubiquitin-proteasome system (UPS) and causes apoptosis through induction of ER stress and deregulation of Bcl-2 proteins. We found that palmitate and the proteasome inhibitor MG132 induced ER stress in β-cells, resulting in decreased expression of the prosurvival proteins Bcl-2, Mcl-1, and Bcl-XL, and upregulation of the prodeath BH3-only protein PUMA. On the other hand, pharmacological activation of the UPS by sulforaphane ameliorated ER stress, upregulated prosurvival Bcl-2 proteins, and protected β-cells from FFA-induced cell death. Furthermore, transgenic overexpression of Bcl-2 protected islets from FFA-induced cell death in vitro and improved glucose-induced insulin secretion in vivo. Together our results suggest that targeting the UPS and Bcl-2 protein expression may be a valuable strategy to prevent β-cell demise in type 2 diabetes.