Melbourne Dental School - Research Publications

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    Remineralisation of enamel and dentine with stabilised stannous fluoride dentifrices in a randomised cross-over in situ trial
    Fernando, J ; Shen, P ; Yuan, Y ; Adams, G ; Reynolds, C ; Reynolds, E (ELSEVIER SCI LTD, 2024-04)
    OBJECTIVES: To compare the remineralisation efficacy and ion bioavailability of two novel SnF2-containing dentifrices in a blinded, cross-over, randomised in situ clinical study. METHODS: Six participants wore removal palatal appliances holding human enamel and dentine blocks with subsurface lesions. Appliances were worn for two treatment periods of 14 consecutive days each, with a one-week washout period in-between. Participants were randomly allocated to rinse with a 1:5 diluted coded slurry of one of two dentifrices containing either 5 % casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) +1100 ppm F as SnF2 [MIPOP], or 1100 ppm F as SnF2 [CT], for 1 min, four times a day. Saliva was collected post-treatment and analysed for tin, calcium, inorganic phosphate and fluoride ions using atomic absorption spectrophotometry and ion chromatography. Enamel and dentine lesions were analysed for percent remineralisation (%R) using transverse microradiography and percent surface microhardness recovery (%SMHR). RESULTS: MIPOP released significantly higher F (3.00 ± 0.27 mM), Ca (15.23 ± 3.23 mM) and Sn (1.18 ± 0.13 mM) into saliva whereas CT released 2.89 ± 0.32 mM F and only 0.84 ± 0.11 mM Ca and 0.28 ± 0.10 mM Sn. MIPOP produced significantly higher %R than CT: 25.6 ± 1.5 % compared to 15.2 ± 0.7 % in enamel, and 33.6 ± 3.1 % compared to 20.6 ± 1.1 % in dentine. Additionally, MIPOP produced significantly higher %SMHR (18.2 ± 7.9 %) compared to CT (4.1 ± 0.6 %). CONCLUSIONS: Both dentifrices promoted remineralisation, but the MIPOP dentifrice with added CPP-ACP and the ion-stabilising effects of CPP released higher amounts of bioavailable tin and produced significantly higher remineralisation and surface microhardness recovery. CLINICAL SIGNIFICANCE: Modern dentifrices contain SnF2 for a range of oral health benefits. Challenges associated with stability of these formulations can affect ion bioavailability, reducing efficacy. Two dentifrices with SnF2 promoted remineralisation in situ, however the dentifrice with the added saliva biomimetic CPP-ACP was superior and therefore may produce greater health benefits.
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    Preparedness for practice of newly qualified dental practitioners in the Australian context: an exploratory study
    Marino, R ; Delany, C ; Manton, DJ ; Reid, K ; Satur, J ; Crombie, F ; Wong, R ; McNally, C ; Adams, GG ; Lopez, D ; Celentano, A ; Lim, M ; Morgan, M (BMC, 2022-08-18)
    BACKGROUND: The current study explored the perspectives of preparedness for dental practice from a range of relevant stakeholders (i.e., educators, employers, final-year students, graduates, practitioners, and professional associations) using an anonymous online survey in which participants described either their preparedness for practice, or the preparedness of graduates they have encountered, across six domains. RESULTS: A total of 120 participants completed the survey. Participants were from several Australian states and territories; regional, rural, and urban locations; and working in the public and private sector. Students and new graduates generally felt prepared for activities in all the identified domains. Stakeholders reported consistently that the knowledge of dental profession graduates was at the required level to enter practice in Australia in a safe way. Activities involving the knowledge of clinical entrepreneurship and financial solvency were the dimensions where students and graduates felt least prepared (e.g., explaining fees, negotiating finances). In the domains involving clinical and technical competencies, students and new graduates self-assessed as less prepared around managing dental trauma and medical emergencies. On the other hand, activities around social and community orientation, and to a lesser extent professional attitudes and ethical judgements, were the dimensions where students and graduates felt the most prepared. CONCLUSIONS: Present findings indicate that there appear to be good standards of preparedness for practice for graduate dental professionals. This exploratory study provides insights into the nature of preparedness for Australian dental professionals and provides a basis for targeting education and professional development to address areas of need.
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    Oral health professionals screening for undiagnosed type-2 diabetes and prediabetes: the iDENTify study
    Marino, R ; Priede, A ; King, M ; Adams, GG ; Sicari, M ; Morgan, M (BMC, 2022-07-18)
    BACKGROUND: As part of an evaluation of an oral healthcare practice-based model that identifies patients with prediabetes or type-2 diabetes, this study reports on the proportion of patients identified with clinically confirmed type-2 diabetes (T2D)/prediabetes and barriers of implementation of the model. METHODOLOGY: Urban and rural oral healthcare practices were invited to participate. Participating practices invited eligible patients to participate in the screening program using the Australian Type-2 Diabetes Risk Assessment Tool (AUSDRISK). Participants were categorised as low, intermediate, or high-risk for prediabetes/T2D. Patients in the intermediate or high-risk category were referred to their General Medical Practitioner (GP) for further investigation. RESULTS: Fifty-one oral healthcare practices and 76 Oral Health Professionals (OHP) participated (60 Dentists, 8 Dental Hygienists, 8 Oral Health Therapists). 797 patients were screened; 102 were low-risk; 331 intermediate-risk; and 364 high-risk for T2D. Of the 695 participants in the intermediate or high-risk groups, 386 (55.5%) were referred to their GP for T2D assessment. Of them, 96 (25.0%) results were returned to OHPs. Of the returned results, six were (6.3%) diagnosed with pre-T2D. CONCLUSION: Patients found to have undiagnosed T2D/prediabetes (6.3%) were within the expected range reported in the literature. Findings indicate that identifying individuals at an elevated risk of having or developing T2D is effective, feasible and could be incorporated into oral healthcare settings. However, this integration may require additional OHPs training and education to ensure that patients at elevated risk of T2D are referred for further assessment.
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    Breastmilk influences development and composition of the oral microbiome
    Butler, CA ; Adams, GG ; Blum, J ; Byrne, SJ ; Carpenter, L ; Gussy, MG ; Calache, H ; Catmull, D ; Reynolds, EC ; Dashper, SG (TAYLOR & FRANCIS LTD, 2022-12-31)
    BACKGROUND: Human microbiomes assemble in an ordered, reproducible manner yet there is limited information about early colonisation and development of bacterial communities that constitute the oral microbiome. AIM: The aim of this study was to determine the effect of exposure to breastmilk on assembly of the infant oral microbiome during the first 20 months of life. METHODS: The oral microbiomes of 39 infants, 13 who were never breastfed and 26 who were breastfed for more than 10 months, from the longitudinal VicGeneration birth cohort study, were determined at four ages. In total, 519 bacterial taxa were identified and quantified in saliva by sequencing the V4 region of the bacterial 16S rRNA genes. RESULTS: There were significant differences in the development of the oral microbiomes of never breastfed and breastfed infants. Bacterial diversity was significantly higher in never breastfed infants at 2 months, due largely to an increased abundance of Veillonella and species from the Bacteroidetes phylum compared with breastfed infants. CONCLUSION: These differences likely reflect breastmilk playing a prebiotic role in selection of early-colonising, health-associated oral bacteria, such as the Streptococcus mitis group. The microbiomes of both groups became more heterogenous following the introduction of solid foods.
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    Temporal development of the infant oral microbiome
    Blum, J ; Silva, M ; Byrne, SJ ; Butler, CA ; Adams, GG ; Reynolds, EC ; Dashper, SG (TAYLOR & FRANCIS LTD, 2022-11-02)
    The human oral microbiome is becoming recognized as playing roles in health and disease well beyond the oral cavity over the lifetime of the individual. The oral microbiome is hypothesized to result from specific colonization events followed by a reproducible and ordered development of complex bacterial communities. Colonization events, proliferation, succession and subsequent community development are dependent on a range of host and environmental factors, most notably the neonate diet. It is now becoming apparent that early childhood and prenatal influences can have long term effects on the development of human oral microbiomes. In this review, the temporal development of the infant human oral microbiome is examined, with the effects of prenatal and postnatal influences and the roles of specific bacteria. Dietary and environmental factors, especially breastfeeding, have a significant influence on the development of the infant oral microbiome. The evidence available regarding the roles and functions of early colonizing bacteria is still limited, and gaps in knowledge where further research is needed to elucidate these specific roles in relation to health and disease still exist.
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    Microbiome profiles of non-responding and responding paired periodontitis sites within the same participants following non-surgical treatment
    Byrne, SJ ; Chang, D ; Adams, GG ; Butler, CA ; Reynolds, EC ; Darby, IB ; Dashper, SG (TAYLOR & FRANCIS LTD, 2022-12-31)
    AIM: Periodontitis is a site-specific, chronic disease treated by non-surgical debridement of subgingival plaque. We aimed to determine the microbiome of sites that did not respond to this treatment (NR) compared with paired good responding (GR) sites before and after treatment. MATERIALS AND METHODS: In a longitudinal cohort study, clinical parameters of disease and biological samples were taken prior to and 3 months after treatment. Twelve NR sites from six participants were paired with GR sites within the same participant. Subgingival plaque samples were subjected to bacterial community analysis using 16S rRNA gene sequencing. RESULTS: There were no significant differences in clinical parameters and microbial communities at baseline between GR and NR sites. Bacterial communities in deep pockets were dominated by a small number of species, notably Porphyromonas gingivalis and Treponema denticola. In NR sites three months after treatment there was no significant change in bacterial composition whilst there was a collapse in the abundance of pathobionts in GR sites. CONCLUSION: NR sites were not identifiable prior to treatment by clinical or microbiological parameters. Treatment failed to disrupt pathogenic bacterial community in NR sites. Targeted suppression of particular species should be considered to initiate community collapse and aid disease resolution.
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    The prebiotic effect of CPP-ACP sugar-free chewing gum
    Fernando, JR ; Butler, CA ; Adams, GG ; Mitchell, HL ; Dashper, SG ; Escobar, K ; Hoffmann, B ; Shen, P ; Walker, GD ; Yuan, Y ; Reynolds, C ; Reynolds, EC (ELSEVIER SCI LTD, 2019-12)
    OBJECTIVES: To determine if chewing gum containing casein phosphopeptide stabilised amorphous calcium phosphate (CPP-ACP) promoted an increase in the abundance of Streptococcus sanguinis and other species associated with dental health in supragingival plaque in a clinical study. MATERIALS AND METHODS: Nineteen participants were recruited for a three-leg cross-over, randomised, controlled clinical trial. Participants chewed a sugar-free gum with or without CPP-ACP six times daily for 20 min over two weeks. The study also involved no gum chewing (no gum) for the same two week period. Participants were randomly assigned to one of the test gums or no gum for each intervention period. Participants abstained from oral hygiene and had washout periods of two weeks between intervention periods. After each intervention period, supragingival plaque was collected and analysed for bacterial composition by sequencing the V4 variable region of the 16S rRNA gene. Data were analysed using a linear mixed model. RESULTS: The CPP-ACP gum intervention produced a significant (p < 0.01) increase in the proportions of S. sanguinis (112%), as well as the commensal species Rothia dentocariosa (127%), Corynebacterium durum (80%) and Streptococcus mitis (55%) when compared with the no gum intervention. All the species that were promoted by the CPP-ACP gum are known to possess one or both of the alkali-producing enzymes arginine deiminase and nitrate reductase. CONCLUSION: This clinical study demonstrated that chewing a sugar-free gum containing CPP-ACP promoted prebiosis by significantly increasing the proportion of S. sanguinis and other health-associated bacterial species in supragingival plaque. CLINICAL SIGNIFICANCE: Regular chewing of CPP-ACP sugar-free gum increases the proportions of health-associated commensal species in supragingival plaque to promote prebiosis and oral homeostasis.
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    Oral candidal carriage in asymptomatic patients
    Mun, MSS ; Yap, T ; Alnuaimi, AD ; Adams, GG ; McCullough, MJ (WILEY-BLACKWELL, 2016-06)
    BACKGROUND: Interest in the association between oral cancer risk and Candida-associated promotion of mucosal dysplasia continues. However, little is known of the presence and amount of oral yeast in the mouths of healthy patients without mucosal lesions. The purpose of this prospective cross-sectional clinical study was to ascertain the prevalence and degree of carriage of Candida in the oral cavities of a non-cancer population, with reference to a range of parameters affecting the oral environment. METHODS: Oral rinse samples were collected from a sample of 203 patients attending the Royal Dental Hospital of Melbourne and analysed for the presence and degree of colonization of yeast species that were phenotypically identified as albicans and non-albicans species. RESULTS: Oral yeast carriage was found in 98/203 patients (48.3%), and of these, 83 (84.7%) patients carried C. albicans. There was no statistical difference in carriage when comparing gender, age, or presence of a removable prosthesis. CONCLUSIONS: Both smoking and the presence of active carious lesions were found to be positively correlated with the carriage of oral Candida. Individuals who are current smokers are nearly seven times more likely to have oral Candida, and participants with high candidal colonization are more likely to be current smokers. Participants with active carious lesions were also more likely to carry oral Candida.
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    Attitudes and opinions of Oral healthcare professionals on screening for Type-2 diabetes
    Marino, R ; Priede, A ; King, M ; Adams, GG ; Lopez, D (BMC, 2021-07-27)
    BACKGROUND: As part of a larger study on the identification of undiagnosed Type 2 diabetes (T2D), and prediabetes patients in dental settings, this study explored oral healthcare professionals' (OHP) attitudes with respect to the relevance and appropriateness of screening for prediabetes/T2D in general oral healthcare settings. It also aims to gain a deeper understanding of OHPs' concerns and perceived barriers to screening for T2D. METHODS: Semi-structured interviews were conducted with 11 OHPs: eight dentists, two dental hygienists and one oral health therapist. Interviews were audio recorded, transcribed verbatim and analysed using thematic analysis. RESULTS: Themes that emerged from the interviews were organised under three major categories: 1) Implementation: OHPs willingness to screen for prediabetes/T2D; 2) Barriers to implementation of screenings; subdivided into: a) lack of knowledge and formal training about T2D screening methodology; b) concerns about patients' awareness and acceptance of T2D screening in oral healthcare settings; c) costs and reimbursement for the time and resources required to screen patients; and d) legal and scope of practice; and 3) Collaboration and communication between OHPs and General practitioners (GP). CONCLUSIONS: The oral healthcare setting was considered as appropriate for medical screening, and OHPs were willing to participate in screening for prediabetes/T2D. Nonetheless, for the successful implementation of a screening programme, several barriers need to be addressed, and effective medical screening would require collaboration between oral health and medical and other health professionals, as well as clarification of legal and reimbursement issues.
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    Anticariogenic efficacy of a saliva biomimetic in head-and-neck cancer patients undergoing radiotherapy
    Sim, CPC ; Walker, GD ; Manton, DJ ; Soong, YL ; Wee, JTS ; Adams, GG ; Reynolds, EC (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.