Melbourne Dental School - Research Publications
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ItemHypomineralized second primary molars: prevalence, defect characteristics and relationship with dental caries in Melbourne preschool children(WILEY, 2018-03)BACKGROUND: Dental caries and enamel defects (DDE) are prevalent amongst children. The presence of DDE, especially enamel hypomineralization, may increase caries experience. The reported prevalence of hypomineralized second primary molars (HSPM) is 2.7-21.8%, although the occurrence in Australian children remains unknown. These HSPM represent a potential predictive factor for molar-incisor hypomineralization (MIH). METHODS: In total, 623 children aged 3-5 years from 30 randomly selected kindergartens participated. The HSPM were recorded using an index combining the European Academy of Paediatric Dentistry MIH Judgment Criteria and modified DDE Index. Caries was recorded using International Caries Detection and Assessment System criteria. RESULTS: In total, 144 HSPM were observed in 88 of the 623 (14.1%) children, a tooth-level prevalence of 5.8%. The prevalence of dentinal carious lesions was 13.2%, and caries prevalence (d2-6 mft > 0) was 36.4%. Cavitated carious lesions affected 30.7% of HSPM. CONCLUSIONS: The relationship between an increase in HSPM lesion extent and increasing number of HSPM per child was statistically significant. A positive association between HSPM severity and extent at tooth level existed (P < 0.05). There was a positive relationship between the extent of HSPM and carious lesion severity (P < 0.05). In this population, children with HSPM did not have overall greater caries experience.
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ItemStatus and progress of treatment methods for root caries in the last decade: a literature review(WILEY, 2018-03)The aim of this literature review is to explore the treatment methods for root caries in laboratory and clinical research in the last decade. A systematic search of publications in PubMed and Web of Science databases was performed. The timespan was limited to the last 10 years and English language. Further retrieval was conducted using the search terms of specific therapies or treatments. Eighty-two articles were included in this systematic review and full texts were retrieved. Types of studies included laboratory studies and clinical trials. Therapeutic approaches for root caries without risk of pulp exposure can be categorized into non-invasive and restorative treatment. Non-invasive treatments which targeted different causative factors of root caries have been developed in the last decade. Accordingly, several artificial caries model systems have been proposed for the study of root caries in the laboratory. Carious tissue excavation techniques and restorative materials and procedures have been modified to improve the prognosis of invasive treatment. It is of importance to determine the most appropriate therapy for root caries and further clinical trials are needed to draw firm conclusions concerning the efficacy and consistency of the various treatment methods proposed.
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ItemInteraction of lifestyle, behaviour or systemic diseases with dental caries and periodontal diseases: consensus report of group 2 of the joint EFP/ORCA workshop on the boundaries between caries and periodontal diseases(WILEY, 2017-03)UNLABELLED: Periodontal diseases and dental caries are the most common diseases of humans and the main cause of tooth loss. Both diseases can lead to nutritional compromise and negative impacts upon self-esteem and quality of life. As complex chronic diseases, they share common risk factors, such as a requirement for a pathogenic plaque biofilm, yet they exhibit distinct pathophysiologies. Multiple exposures contribute to their causal pathways, and susceptibility involves risk factors that are inherited (e.g. genetic variants), and those that are acquired (e.g. socio-economic factors, biofilm load or composition, smoking, carbohydrate intake). Identification of these factors is crucial in the prevention of both diseases as well as in their management. AIM: To systematically appraise the scientific literature to identify potential risk factors for caries and periodontal diseases. METHODS: One systematic review (genetic risk factors), one narrative review (role of diet and nutrition) and reference documentation for modifiable acquired risk factors common to both disease groups, formed the basis of the report. RESULTS & CONCLUSIONS: There is moderately strong evidence for a genetic contribution to periodontal diseases and caries susceptibility, with an attributable risk estimated to be up to 50%. The genetics literature for periodontal disease is more substantial than for caries and genes associated with chronic periodontitis are the vitamin D receptor (VDR), Fc gamma receptor IIA (Fc-γRIIA) and Interleukin 10 (IL10) genes. For caries, genes involved in enamel formation (AMELX, AMBN, ENAM, TUFT, MMP20, and KLK4), salivary characteristics (AQP5), immune regulation and dietary preferences had the largest impact. No common genetic variants were found. Fermentable carbohydrates (sugars and starches) were the most relevant common dietary risk factor for both diseases, but associated mechanisms differed. In caries, the fermentation process leads to acid production and the generation of biofilm components such as Glucans. In periodontitis, glycaemia drives oxidative stress and advanced glycation end-products may also trigger a hyper inflammatory state. Micronutrient deficiencies, such as for vitamin C, vitamin D or vitamin B12, may be related to the onset and progression of both diseases. Functional foods or probiotics could be helpful in caries prevention and periodontal disease management, although evidence is limited and biological mechanisms not fully elucidated. Hyposalivation, rheumatoid arthritis, smoking/tobacco use, undiagnosed or sub-optimally controlled diabetes and obesity are common acquired risk factors for both caries and periodontal diseases.
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ItemEffect of a self-adhesive coating on the load-bearing capacity of tooth-coloured restorative materials(WILEY, 2017-03)BACKGROUND: The aim of this study was to compare the flexural strength and Vickers hardness of tooth-coloured restorative materials with and without applying a self-adhesive coating for up to 6 months. METHODS: Specimens were prepared from three resin composites (RC), two resin-modified glass-ionomer cements (RM-GIC) and two conventional glass-ionomer cements (CGIC). All materials were tested both with and without applying G-Coat Plus (GCP). Specimens were conditioned in 37 °C distilled deionized water for 24 h, and 1, 3 and 6 months. The specimens were strength tested using a four-point bend test jig in a universal testing machine. The broken specimen's halves were used for Vickers hardness testing. Representative specimens were examined under an environmental scanning electron microscope. RESULTS: Data analysis showed that regardless of time and materials, generally the surface coating was associated with a significant increase in the flexural strength of the materials. Applying the GCP decreased the hardness of almost all materials significantly (P < 0.05) and effect of time intervals on hardness was material dependent. CONCLUSIONS: The load-bearing capacity of the restorative materials was affected by applying self-adhesive coating and ageing. The CGIC had significantly higher hardness but lower flexural strength than the RM-GIC and RC.
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ItemAn investigation into the effect of a resin infiltrant on the micromechanical properties of hypomineralised enamel(WILEY, 2017-09)BACKGROUND: Resin infiltration may alter the mechanical properties of enamel hypomineralised lesions (HL); however, variable surface layer (SL) thickness may affect resin penetration. AIMS: To determine the thickness of the SL of HL and to investigate the effect of resin infiltration on the mechanical properties of HL. DESIGN: The thickness of the SL over HL was determined using polarised light microscopy. Etching time using 15% HCl gel to remove the SL of 52 samples was determined. Selected HL and control areas of 21 teeth were infiltrated with Icon® resin infiltrant, and cross-sectional Knoop microhardness (KHN) measurements were recorded before and after resin infiltration. RESULTS: Ninety-six point five per cent of HL had a detectable SL with mean thickness of 58 ± 29 μm. Application of HCl for 120 s produced a mean MIH erosion depth of 58 ± 12 μm. Eleven of 21 samples had evidence of infiltration using visual examination. The infiltrant penetrated some of the HL leading to an increase in KHN (111 ± 75 KHN) which, when compared to adjacent non-infiltrated HL (96 ± 52 KHN), was not statistically significantly different (P = 0.56). CONCLUSIONS: There was marked variation in the SL thickness of HL. Resin infiltration of HL did not increase microhardness significantly.
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ItemEtiology of molar incisor hypomineralization - A systematic review(WILEY, 2016-08)OBJECTIVES: Molar incisor hypomineralization (MIH) is a common developmental dental defect of permanent teeth, which can increase the risk of dental caries, infection and hospitalization. The etiology is currently unclear although prenatal or early childhood health factors are suspected. The aim of this systematic review was to assess the strength of evidence linking etiological factors with MIH. METHODS: A systematic search was conducted using the Medline and Embase electronic databases for studies investigating environmental etiological factors of MIH. Two reviewers assessed the eligibility of studies. The level of evidence and bias was determined for all eligible studies according to Australian National Health and Medical Research Council guidelines for systematic reviews of etiology and the Newcastle-Ottawa Scale. RESULTS: From a total of 2254 studies identified through electronic and hand searching, 28 were eligible for inclusion. Twenty-five of these investigated MIH and three investigated a related condition in primary teeth, hypomineralized second primary molars (HSPM), and these were analysed separately. A limited number of studies reported significant associations between MIH and pre- and perinatal factors such as maternal illness and medication use in pregnancy, prematurity and birth complications. Early childhood illness was implicated as an etiological factor in MIH in several studies, in particular fever, asthma and pneumonia. The studies investigating HSPM revealed an association with maternal alcohol consumption, infantile fever and ethnicity. However, the validity of these findings is impaired by study design, lack of adjustment for confounders, lack of detail and consistency of exposures investigated and poor reporting. CONCLUSIONS: Childhood illness is likely to be associated with MIH. Further prospective studies of the etiology of MIH/HSPM are needed.
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ItemCaries experience of children with cardiac conditions attending the Royal Children's Hospital of Melbourne(WILEY, 2018-12)BACKGROUND: Poor oral health in children with cardiac conditions can have negative effects on quality of life and increased risk of infective endocarditis. The aim of this study was to investigate the caries experience in children with cardiac conditions attending the Royal Children's Hospital, Melbourne. METHODS: Medical and dental records of 428 children aged <12 years were examined. Cardiac and other medical diagnoses, decayed, missing and filled surfaces/teeth were recorded and analysed. Children referred for reasons other than caries management (NRCM) was analysed separately to address confounding of referral reason on caries experience. RESULTS: Mean age of overall study population was 4.9 (SD 2.4) years, caries prevalence 52.1%, mean dmft 3.65 (SD 4.8), mean dmfs 6.19 (SD 11.3), enamel defects prevalence 29.2%. Mean age of NRCM group was 4.6 (SD 2.4) years, caries prevalence 37.5%, mean dmft 2.37 (SD 4.2), mean dmfs 4.22 (SD 9.4), enamel defects prevalence 23.0%. Untreated carious lesions accounted for 89.9% of caries experience. Caries experience was associated with low socio-economic status, absence of comorbidity and enamel defect presence. CONCLUSIONS: High disease levels were observed. Age, socio-economic status and enamel defects were associated with caries experience, not severity of cardiac diagnoses. Early referral for dental care and improved access should be facilitated.
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ItemCarious lesion severity and demarcated hypomineralized lesions of tooth enamel in schoolchildren from Melbourne, Australia(WILEY, 2018-09)BACKGROUND: Developmental hypomineralized lesions of enamel (DHL) may represent a significant caries-risk factor. The aim of this study was to determine the association between carious lesion severity and DHL in 6- to 12-year-old schoolchildren from Melbourne, Australia. METHODS: The sample was derived from randomly selected schools in inner Melbourne. A full dental examination was performed at the school. Socio-demographic data, caries experience (DMFT/dmft/ICDAS II) and the consequences of untreated carious lesions (PUFA/pufa) were measured. DHL, molar incisor hypomineralization (MIH) and hypomineralized second primary molar (HSPM) presence were assessed using the European Academy of Paediatric Dentistry (EAPD) criteria. RESULTS: Of the children examined (n = 327), 26.9% had DHL. The prevalence of MIH and HSPM was 14.7% and 8%, respectively. Almost 20% of children had severe carious lesions (ICDAS 5 & 6) in at least one permanent or primary tooth. Ordinal regression analyses indicated that DHL (OR = 2.17; 95% CI: 1.35-3.49) and being born overseas (OR = 2.59, 95% CI: 1.66-4.06) increased the likelihood of severe carious lesions. CONCLUSIONS: One of four children had DHL. DHL-affected children had an increased likelihood of presenting untreated severe carious lesions compared with DHL-free children.
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ItemXerostomia, salivary characteristics and gland volumes following intensity-modulated radiotherapy for nasopharyngeal carcinoma: a two-year follow up(WILEY, 2018-06)BACKGROUND: To evaluate changes in xerostomia status, salivary characteristics and gland volumes 2 years following radiotherapy in nasopharyngeal carcinoma patients. METHODS: Xerostomia scores, salivary flow rates, pH and buffering capacity were measured at pre-radiotherapy, mid-radiotherapy, 2 weeks, 3 months and 2 years post-radiotherapy. Salivary gland volumes and their correlation with radiation dose were also assessed. RESULTS: Mean radiation dose to oral cavity, parotid and submandibular glands (SMG) was 44.5, 65.0 and 38.6 Gy respectively. Parotid and SMG volumes decreased 33% at 3 months post-radiotherapy; volumes at 2 years post-radiotherapy were 84% and 51% of pre-radiotherapy levels, respectively. Correlations were observed between parotid gland volume per cent reduction and its radiation dose and between resting salivary flow rate reduction and post-radiotherapy/pre-radiotherapy SMG volume ratio. Salivary flow rates and resting saliva pH remained significantly low at 2 years post-radiotherapy (both flow rates, P = 0.001; resting saliva pH, P = 0.005). Similarly, xerostomia scores remained significantly higher compared with pre-radiotherapy levels. CONCLUSIONS: Submandibular gland volumetric shrinkage persisted 2 years after radiotherapy. Xerostomia scores remained significantly higher, and salivary flow rates and resting saliva pH remained significantly lower, suggesting that study participants were still at risk for hyposalivation-related oral diseases.
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