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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ItemCarious lesion management in children and adolescents by Australian dentists(WILEY, 2019-09)BACKGROUND: The management of carious lesions in children and adolescents can have lifelong implications for the patient. The aim of this study was to assess the decision-making process of dentists when managing carious lesions in children and adolescents. METHODS: Approximately, 11 000 dentists listed as members of the Australian Dental Association Inc. (ADA) and Australian and New Zealand Society of Paediatric Dentistry (ANZSPD) were emailed a link in April 2017 to a 19-question survey delivered by SurveyMonkey™. RESULTS: In this study, 887 responses were received. In 'enamel-limited' carious lesions, dentists intervened most frequently in primary tooth approximal (365, 41.1%), followed by permanent tooth occlusal (295, 33.3%) and approximal (244, 27.5%), and primary tooth occlusal (203, 22.9%) surface carious lesions. Age, university of graduation, practicing state, decade of graduation and frequency of treatment of children between 6 and 15 years were significant demographic factors influencing the restorative threshold. CONCLUSIONS: Australian dentists reported significant variation in their management of approximal and occlusal carious lesions in both primary and permanent teeth. A substantial proportion of respondents would intervene surgically on non-cavitated enamel-limited lesions.
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ItemDifferential diagnoses of enamel hypomineralisation in an archaeological context: A postmedieval skeletal collection reassessment(WILEY, 2019-09)Abstract Developmental enamel defects (DDE) are often used as indicators of general health in past archaeological populations. DDE include three common types of lesions: hypoplasia, diffuse, and demarcated opacities. Molar incisor hypomineralisation (MIH) was defined in 2001 as a qualitative enamel defect affecting first permanent molars and often permanent incisors. The European Academy of Paediatric Dentistry established criteria to diagnose MIH in current populations as demarcated white or yellow‐brown opacities of enamel with or without posteruptive breakdown. MIH is prevalent in current populations (average 14.2%) and may cause important damage to first permanent molars. Aetiological factors are uncertain. The discovery of MIH in archaeological skeletal collections based on macroscopic examination has been reported previously, in particular by Ogden and colleagues (2008). If MIH exists in past populations, there are profound implications regarding current aetiological hypotheses. Aims of the present study were to (a) reassess the London postmedieval archaeological collection from which the first cases of MIH were reported and evaluate the reliability of MIH diagnosis criteria in past populations and (b) differentially diagnose developmental defects of enamel and post mortem discoloration in the teeth. Contrary to the reported prevalence in the original study (93.2%), among 47 subadult (>18 years) individuals, a low MIH prevalence was determined (27%). Reliability of MIH diagnosis was tested with three MIH experts who were also physical anthropologists. Our study highlighted that the reliability of a macroscopic diagnosis of MIH in past populations is fair (Cohen's kappa = 0.35 ± 0.11; Fleiss's kappa = 0.3). It could explain the large differential in prevalence values in studies performed in archaeological collections. Pathological and taphonomic agents can produce enamel modifications indistinguishable from one another, even to an “experienced eye.” Here, we examined the literature to highlight potential differential diagnoses of MIH (taphonomic discoloration, amelogenesis imperfecta, fluorosis, rachitic teeth, etc.). Employing nondestructive analyses to characterise and diagnose tooth discoloration in past populations is highly recommended.
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ItemValidity and reproducibility testing of the Molar Incisor Hypomineralisation (MIH) Index(WILEY, 2019-01)BACKGROUND: To address challenges presented to clinicians to diagnose and treat molar incisor hypomineralisation (MIH), a new assessment tool was created. AIM: To explore the reproducibility and validity of a new instrument developed to assess MIH. METHODS: Inter-rater and test-retest reliabilities were examined using Cronbach's alpha. Thirty-five oral health professionals scored clinical photographs for the presence/absence of MIH and other enamel defects using the new index. Face, content, and construct validities were assessed. A panel of six experienced researchers assessed face validity. Construct validity was determined by examining hypothesised associations with clinical variables reported to change concurrently or as modifiers of the MIH outcome. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were also assessed. RESULTS: The index reflected the hypothesised associations regarding the presence, prevalence, and severity of MIH, demonstrating construct validity. Researchers indicated that codes and definitions were clear and suitable for international use. The index showed satisfactory scores of sensitivity/specificity and PPV/NPV. Examiners achieved "Substantial" to "Almost perfect" levels of agreement in clinical presentation and lesion extension. CONCLUSIONS: The tested MIH index had reasonably solid properties providing confidence that it is a reliable and valid instrument for use in population-based and clinical screenings for diagnosis of MIH and other enamel defects.
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ItemAnticariogenic efficacy of a saliva biomimetic in head-and-neck cancer patients undergoing radiotherapy(WILEY, 2019-03)BACKGROUND: The aim of this study was to investigate the effect of treatment with the saliva biomimetic, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and SnF2 /NaF compared with SnF2 /NaF alone on coronal surface caries progression in head-and-neck cancer patients undergoing radiotherapy. METHODS: Twenty-four participants were randomized into two groups. Both groups used 0.4% SnF2 gel and a 0.32% NaF toothpaste; the test group also applied a crème containing 10% CPP-ACP three times daily while the control group used an identical crème without CPP-ACP (placebo). Resting saliva flow rate and saliva fluoride concentrations were determined. Caries status was assessed using ICDASII at baseline and 12-weeks postradiotherapy. Data were statistically analysed using a linear mixed effects model. RESULTS: Both groups showed significantly reduced resting saliva flow rate (P < 0.001) postradiotherapy. There were no significant differences in flow rates and fluoride concentration between groups. The CPP-ACP group exhibited a significant (P < 0.05) 51% reduction in coronal surface caries progression compared with the placebo group. CONCLUSION: Resting salivary flow rate was significantly reduced in head-and-neck cancer patients following radiotherapy and use of CPP-ACP with SnF2 /NaF significantly lowered caries progression compared with SnF2 /NaF alone.