Melbourne Dental School - Research Publications
Now showing items 1-12 of 322
Cultural competence of Australian dental students
BACKGROUND: Australia possesses a highly multicultural demographic, and thus dental practitioners are likely to regularly encounter culturally and linguistically diverse individuals. It is important for dental practitioners to be culturally competent, however, cultural competency education is highly variable in the curricula of dentistry and oral health courses in Australia, and research is largely limited to dentistry students. This study aims to investigate and compare perceived attitudes, beliefs and practices of cultural competence amongst first and final year Doctor of Dental Surgery (DDS) and Bachelor of Oral Health (BOH) students at the University of Melbourne Dental School. METHODS: Following ethics approval, anonymous questionnaires were completed by 213 participants. The questionnaire was adapted from Schwarz's Healthcare Provider Cultural Competence Instrument and consisted of five scales. Data was analysed using SPSS V 24.0 software. RESULTS: A total of 213 students participated in this study (response rate = 88%) The majority of participants were female (n = 114, 53.5%) and the mean age of 23.5 years (range 18-40). The majority of participants were Australian born (n = 110) with 74.6% (n = 159) first generation Australians. Participants who identified as Australian represented 35.7% (n = 76) with 66.1% (n = 141) identified as partly Australian. Multivariate analysis indicated that, after controlling for other independent variables in the model, those who had the highest cultural competence score were female, who self-identify as "Australian", who were in the final year. Furthermore, those who were in the final BOH year scored significatively higher than final year DDS students. CONCLUSION: The findings of this study suggest that there is a significant difference in students self-reported cultural competence at different stages of their education. This may be attributed to differences in cultural competence education, scope of practice and the type of patient encounters and role modelling that students may experience. Future research should involve follow up to create longitudinal data, as well as research at other dental schools in Australia and overseas.
Differential SOD2 and GSTZ1 profiles contribute to contrasting dental pulp stem cell susceptibilities to oxidative damage and premature senescence
BACKGROUND: Dental pulp stem cells (DPSCs) are increasingly being advocated as viable cell sources for regenerative medicine-based therapies. However, significant heterogeneity in DPSC expansion and multi-potency capabilities are well-established, attributed to contrasting telomere profiles and susceptibilities to replicative senescence. As DPSCs possess negligible human telomerase (hTERT) expression, we examined whether intrinsic differences in the susceptibilities of DPSC sub-populations to oxidative stress-induced biomolecular damage and premature senescence further contributed to this heterogeneity, via differential enzymic antioxidant capabilities between DPSCs. METHODS: DPSCs were isolated from human third molars by differential fibronectin adhesion, and positive mesenchymal (CD73/CD90/CD105) and negative hematopoietic (CD45) stem cell marker expression confirmed. Isolated sub-populations were expanded in H2O2 (0-200 μM) and established as high or low proliferative DPSCs, based on population doublings (PDs) and senescence (telomere lengths, SA-β-galactosidase, p53/p16INK4a/p21waf1/hTERT) marker detection. The impact of DPSC expansion on mesenchymal, embryonic, and neural crest marker expression was assessed, as were the susceptibilities of high and low proliferative DPSCs to oxidative DNA and protein damage by immunocytochemistry. Expression profiles for superoxide dismutases (SODs), catalase, and glutathione-related antioxidants were further compared between DPSC sub-populations by qRT-PCR, Western blotting and activity assays. RESULTS: High proliferative DPSCs underwent > 80PDs in culture and resisted H2O2-induced senescence (50-76PDs). In contrast, low proliferative sub-populations exhibited accelerated senescence (4-32PDs), even in untreated controls (11-34PDs). While telomere lengths were largely unaffected, certain stem cell marker expression declined with H2O2 treatment and expansion. Elevated senescence susceptibilities in low proliferative DPSC (2-10PDs) were accompanied by increased oxidative damage, absent in high proliferative DPSCs until 45-60PDs. Increased SOD2/glutathione S-transferase ζ1 (GSTZ1) expression and SOD activities were identified in high proliferative DPSCs (10-25PDs), which declined during expansion. Low proliferative DPSCs (2-10PDs) exhibited inferior SOD, catalase and glutathione-related antioxidant expression/activities. CONCLUSIONS: Significant variations exist in the susceptibilities of DPSC sub-populations to oxidative damage and premature senescence, contributed to by differential SOD2 and GSTZ1 profiles which maintain senescence-resistance/stemness properties in high proliferative DPSCs. Identification of superior antioxidant properties in high proliferative DPSCs enhances our understanding of DPSC biology and senescence, which may be exploited for selective sub-population screening/isolation from dental pulp tissues for regenerative medicine-based applications.
Oral health promotion practices of Australian community mental health professionals: a cross sectional web-based survey
BACKGROUND: This study explored the oral health promotion practices of Australian community mental health professionals working with people living with severe mental illness (SMI). METHODS: An anonymous cross-sectional web-based survey was distributed to all Community Rehabilitation and Support Workers (CRSWs) working at Neami National (n = 471), an Australian community mental health service. The validated questionnaire assessed participants' self-rated oral health knowledge and confidence (7 questions); their perceived barriers (9 questions) and attitudes (5 questions) to oral health promotion; and their oral health promotion practices (7 questions). Differences in responses between groups were analysed using Chi-square, Fisher's exact and Mann-Whitney U tests. Logistic Regression Analysis served to explore the probability of providing oral health support to mental health consumers. RESULTS: A total of 141 CRSWs were included in this study, achieving a response rate of 30 percent. Roughly two-fifths (39.0%) of participants had oral health training in the previous 12-months. The majority of CRSWs (89.3%) believed ('Agreed' or 'Strongly agreed') that mental health support workers have a role to play in promoting oral health. However, less than half (44.0%) of CRSWs practiced oral health promotion activities when working with mental health consumers. When asked about barriers to promoting oral health, 'lack of consumer interest' was the most prevalent issue. CRSWs who had oral health training were over three-times (OR 3.5, 95% CI 1.25-9.83, p = 0.017) more likely to provide oral health support. Results showed the provision of oral health support was most strongly associated with self-rated knowledge and confidence (OR 4.089, 95% CI 1.629-10.263, p = 0.003) and attitudes to oral health promotion (OR 3.906, 95% CI 1.77-8.65, p = 0.001). CONCLUSION: The results of this study suggest that mental health support workers who have more positive attitudes to oral health promotion and who have higher self-rated oral health knowledge and confidence are more likely to provide oral health support in their professional role. Training for community mental health professionals is essential to build confidence and skills to promote oral health for mental health consumers.
Bioavailable fluoride in calcium-containing dentifrices
(NATURE RESEARCH, 2021-01-08)
Calcium added to dentifrices can complex with fluoride ions to reduce intra-oral bioavailability and therefore efficacy in preventing dental caries. Six commercially available dentifrices containing different types of calcium and fluoride were analyzed for total and bioavailable fluoride levels by adding 10 g of dentifrice to 30 mL of distilled deionized water and mixing vigorously for 1 min to simulate toothbrushing. One milliliter of the dentifrice/water slurry was immediately centrifuged and the supernatant removed for bioavailable fluoride analysis and the mixed slurry prior to centrifugation used for total fluoride analysis using a modified microdiffusion method. The concentration of fluoride was determined using a fluoride ion-selective electrode calibrated with internal fluoride standards. All the dentifrices had similar total fluoride concentrations to those indicated on their labels (94% to 105%). However, only one dentifrice that contained calcium in the form of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) had almost 100% (97%) of fluoride in bioavailable form. The other dentifrices contained calcium carbonate and they exhibited significantly (p < 0.001) lower bioavailable fluoride levels (27% to 61%), through the generation of poorly soluble fluoride phases. The saliva biomimetic CPP, as CPP-ACP, in a dentifrice stabilised calcium and fluoride ions to maintain fluoride's bioavailability.
Trends in Dental Medication Prescribing in Australia during the COVID-19 Pandemic
(SAGE PUBLICATIONS INC, 2021-01-10)
INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic and subsequent restrictions on dental services have had a significant impact on the provision of dental care in Australia and around the world. OBJECTIVES: To investigate the impact of COVID-19 on medications prescribed by dentists under the Australian Pharmaceutical Benefits Scheme (PBS). METHODS: Data on the number of dental prescriptions dispensed for all medications listed on the PBS Dental Schedule, from January 2019 to June 2020, were extracted from publicly available data sets. Analysis of prescription trends was performed for 1) total medications, 2) each major medication class, and 3) individual medications. The number of prescriptions dispensed in each month from January 2020 to June 2020 was compared to the same month in 2019 to determine the relative (percentage) change, and z statistics were used to determine whether changes were statistically significant. RESULTS: There was a significant decrease in dental prescriptions in April 2020 compared to April 2019 (14,785, 18%; P < 0.05). Decreases in prescriptions for antibiotics (10,512, 16%; P < 0.05) and opioid analgesics (3,129, 18%; P < 0.05) were smaller compared to other major medication classes. There was a significant increase in June 2020, compared with June 2019, for prescriptions of amoxicillin with clavulanic acid (4,903, 20%; P < 0.05), tramadol (89, 46%; P < 0.05), and oxycodone (381, 73%; P < 0.05). CONCLUSION: Dental service restrictions during COVID-19 likely drove an unmet need for routine dental treatment, which had significant implications for public oral health following easing of restrictions. During the initial surge and subsequent lockdown, antibiotics and opioid analgesics may have been used an as alternative to routine operative treatment. Continued professional guidance is required to ensure dental prescribing remains evidence based during the pandemic period. KNOWLEDGE TRANSFER STATEMENT: The COVID-19 pandemic and subsequent restrictions on dental practice have had a profound impact on the provision of dental care in Australia and elsewhere in the world. In this context, population-level medication surveillance is important to identify and respond to changes in prescribing patterns that have arisen due to COVID-19 and restrictions on the provision of dental care. This research is particularly important for governments, regulators, and professional associations to ensure therapeutic guidelines and recommendations during the pandemic period remain relevant and evidence based.
Experiences of oral health: before, during and after becoming a regular user of GC Tooth Mousse Plus((R))
BACKGROUND: Clinical trials and laboratory studies from around the world have shown that GC Tooth Mousse Plus® (TMP) is effective in protecting teeth from tooth decay and erosion, buffering dental plaque pH, remineralising white spot lesions and reducing dentine hypersensitivity. However, no other study has assessed the experiences of oral health, before, during and after individuals becoming regular users of TMP. The aim of this study was to identify how participants' oral health status changed after introducing TMP into their oral hygiene routine. METHODS: A qualitative study using Charmaz's grounded theory methodology was conducted. Fifteen purposively sampled regular users of TMP were interviewed. Transcripts were analysed after each interview. Data analysis consisted of transcript coding, detailed memo writing, and data interpretation. RESULTS: Participants described their experiences of oral health and disease, before, during and after introducing TMP into their daily oral hygiene routine, together with the historical, biological, financial, psychosocial, and habitual dimensions of their experiences. Before becoming a regular user of TMP, participants described themselves as having a damaged mouth with vulnerable teeth, dry mouth, and sensitivity. Various aspects of participants' histories were relevant, such as, family history and history of oral disease. Having a damaged mouth with vulnerable teeth, dry mouth and sensitivity was explained by those elements. Despite some initial barriers, once being prescribed TMP by a dental professional, a three-fold process of change was initiated: starting a new oral hygiene routine, persevering daily, and experiencing reinforcing outcomes. This process led to a fundamental lifestyle change. Participants transitioned from having a damaged mouth with vulnerable teeth to having a comfortable mouth with strong teeth; at the same time participants felt empowered by this newly found status of being able to keep their teeth for life. Barriers and facilitators for incorporating TMP on daily oral hygiene routine were also identified. CONCLUSIONS: Participants valued having a comfortable mouth with strong teeth, which did not require repeated restorations. Seeing concrete results in their mouths and experiencing a more comfortable mouth boosted adherence to daily applications of TMP, which was maintained over time.
Utilisation of dental services for people with special health care needs in Australia
BACKGROUND: To explore the profile of patients and treatment delivered at specialist referral centres for individuals with special needs. METHODS: A cross-sectional audit was conducted of the health records of all patients with appointments at two of Australia's largest referral centres for patients with special needs, the Integrated Special Needs Department at the Royal Dental Hospital of Melbourne and the Special Needs Unit at the Adelaide Dental Hospital, for the month of August 2015. RESULTS: The profile of patients treated at these specialist units demonstrates the diversity of individuals with additional health care needs that general dentists feel require specialised oral health care. The Adelaide-based clinic had a greater proportion of complex medical patients in comparison to those treated in Melbourne who were more likely to have a disability or psychiatric condition and were less likely to be able to self-consent for treatment. Interestingly, despite similar workforce personnel numbers, there were approximately twice as many appointments at the Special Needs Unit in Adelaide than the Integrated Special Needs Department in Melbourne during the study period which may have reflected differences in workforce composition with a greater use of dental auxiliaries at the Adelaide clinic. CONCLUSIONS: The results of this study provide an initial profile of patients with special needs referred for specialist care in Australia. However, the differences in patient profiles between the two units require further investigation into the possible influence of service provision models and barriers to access of care for individuals with special needs and to ensure equitable access to health care.
(Re)Defining the Proline-Rich Antimicrobial Peptide Family and the Identification of Putative New Members
(FRONTIERS MEDIA SA, 2020-12-01)
As we rapidly approach a post-antibiotic era in which multi-drug resistant bacteria are ever-pervasive, antimicrobial peptides (AMPs) represent a promising class of compounds to help address this global issue. AMPs are best-known for their membrane-disruptive mode of action leading to bacteria cell lysis and death. However, many AMPs are also known to be non-lytic and have intracellular modes of action. Proline-rich AMPs (PrAMPs) are one such class, that are generally membrane permeable and inhibit protein synthesis leading to a bactericidal outcome. PrAMPs are highly effective against Gram-negative bacteria and yet show very low toxicity against eukaryotic cells. Here, we review both the PrAMP family and the past and current definitions for this class of peptides. Computational analysis of known AMPs within the DRAMP database (http://dramp.cpu-bioinfor.org/) and assessment of their PrAMP-like properties have led us to develop a revised definition of the PrAMP class. As a result, we subsequently identified a number of unknown and unclassified peptides containing motifs of striking similarity to known PrAMP-based DnaK inhibitors and propose a series of new sequences for experimental evaluation and subsequent addition to the PrAMP family.
Porphyromonas gingivalis laboratory strains and clinical isolates exhibit different distribution of cell surface and secreted gingipains
(TAYLOR & FRANCIS LTD, 2021-01-01)
Background: The cell-surface cysteine proteinases RgpA, RgpB (Arg-gingipain), and Kgp (Lys-gingipain) are major virulence factors of P. gingivalis, a keystone pathogen in the development of destructive periodontal disease. The gingipains function as proteinases and transpeptidases utilising small peptides such as glycylglycine as acceptor molecules. However, the characteristics of the gingipains from most P. gingivalis strains have not been determined. Methods: We determined the phenotypes of a panel of P. gingivalis laboratory strains and global clinical isolates with respect to growth on blood agar plus whole-cell and vesicle-free culture supernatant (VFSN) Arg- and Lys-specific proteinase activities. Results: The P. gingivalis isolates exhibited different growth characteristics and hydrolysis of haemoglobin in solid media. Whole-cell Arg-gingipain Vmax varied 5.8-fold and the whole cell Lys-gingipain Vmax varied 2.1-fold across the strains. Furthermore, the P. gingivalis strains showed more than 107-fold variance in soluble Arg-gingipain activity in VFSN and more than 371-fold variance in soluble Lys-gingipain activity in VFSN. Glycylglycine and cysteine stimulated Arg- and Lys-specific cleavage activities of all strains. The stimulation by cysteine was in addition to its redox effect consistent with both glycylglycine and cysteine promoting transpeptidation. Conclusion: The global P. gingivalis clinical isolates exhibit different Arg- and Lys‑gingipain activities with substantial variability in the level of soluble proteinases released into the environment.
Comparison of 6-mm and 11-mm dental implants in the posterior region supporting fixed dental prostheses: 5-year results of an open multicenter randomized controlled trial.
OBJECTIVE: The aim of this multicenter, randomized controlled trial was to compare the clinical and radiographic outcomes of 6-mm or 11-mm implants, placed in the posterior maxilla and mandible, during a 5-year follow-up period. MATERIALS AND METHODS: Ninety-five patients with adequate bone height for 11-mm implants, were randomly allocated to a 6-mm group (test group with short implants) or an 11-mm group (control group with standard-length implants). Two or three implants of the same length were placed in each patient and after 6 weeks loaded with a splinted provisional restoration. This was followed by definitive splinted restoration 6 months after implant placement. Clinical and radiographic parameters, including the occurrence of complications were recorded. RESULTS: A total of 49 patients were enrolled to receive 6-mm implants (n = 108) and 46 patients to receive 11-mm implants (n = 101). Three implants (two of 6 mm and one of 11 mm in length) were lost before loading and one 6-mm implant after 15 months of function, and one 11-mm implant was lost during the first year of function. The 5-year survival rates were 96.0% and 98.9% in the 6-mm and 11-mm group, respectively. The mean marginal bone level changes 5 years post-loading were 0.01 ± 0.45 mm (bone gain) in the 6-mm group and -0.12 ± 0.93 mm (bone loss) in the 11-mm group (p = .7670). Clinical parameters, including plaque, bleeding on probing and pocket probing depth were not significantly different between the groups, and also technical complications were low. CONCLUSION: The clinical and radiographic outcomes of 6-mm short and 11-mm standard-length implants were not different during a 5-year evaluation period.
Distinct phenolic, alkaloid and antioxidant profile in betel quids from four regions of Indonesia
(NATURE RESEARCH, 2020-10-01)
Betel quid (BQ) is a chewing mixed package that mainly contains areca nut (AN), betel leaf (Leaf) or betel stem inflorescence (SI), and slaked lime, and is consumed with or without tobacco BQ chewing is common in South East Asia and has been strongly associated with malignant and potentially malignant diseases of the oral cavity. Alkaloids such as arecoline are often accounted for the carcinogenic potential of BQ, however the chemical composition of BQ has not been studied in detail. In the current study, we investigated the total phenolic content (TPC), antioxidant activity (by mean of ferric reducing antioxidant power, FRAP), radical scavenging activity (DPPH test), polyphenolic profile and arecoline content in different components of BQ, namely AN, Leaf or SI, Husk, and blended BQ (BQ mix, containing AN, Leaf or SI and slaked lime). Samples were imported from 4 major regions of Indonesia, namely: Banda Aceh (BA), North Sumatra (NS), West Kalimantan (WK) and West Papua (WP). The highest TPC, FRAP, and DPPH values were detected in AN samples compared to other BQ components, while samples from WP region were of higher values compared to the other regions. High performance liquid chromatography-Mass Spectrometry (LC-MS) analysis showed that Husk contains the widest range of polyphenols, including hydroxybenzoic acids, hydroxycinnamic acids, flavanols, flavonols and stilbenes. Catechin and epicatechin were the main polyphenols detected in BQ, and they were present at the highest concentrations in WP-AN sample. Arecoline was detected in all AN and BQ mix samples and was significantly correlated with catechin and epicatechin, and significantly negatively correlated with p-hydroxybenzoic acid. Notably, arecoline concentration changed significantly when AN was blended in BQ mixtures. The current study is the first to extensively characterise the chemical composition of BQ and provides insight for a better understanding of the interactions of BQ alkaloids and phenolics in the development of oral submucous fibrosis and oral cancer.