Oral microbiome research - a call for equity and inclusion.

Over 700 oral bacterial species have been identified in human populations, with ~200 bacterial species identified in any given individual mouth. The relationship between the oral microbiome and health is evidenced in many studies, with dysbiosis (a shift from a healthy to less healthy state of microbial community) associated with dental caries, periodontitis, halitosis and oral cancer. However, oral microbiome research to date has focused primarily on European populations, particularly those in large urban centres housing academic institutions with access to research funding. Key anthropological perspectives examining the sociocultural, epidemiological, genetic and environmental factors that influence the oral microbiome have also been Euro-centric. Very little is known about how the oral microbiome mediates both oral and general disease risks specifically within Indigenous and other vulnerable populations. Undertaking oral microbiome research in under-served communities requires consideration of many issues often unfamiliar in the broader research community, including being acceptable, relevant and of perceived benefit to the communities being studied. Research materials need to be managed respectfully in a culturally safe way, sharing/translating the knowledge obtained. These approaches will likely provide unique insights into the complex connections between environment and biology, people and place, and culture and science in relation to the oral microbiome. The ongoing development of oral microbiome research must facilitate frameworks that are equitable and inclusive to better enable clinical and scientific expertise within marginalised communities.

Oral microbiome research - working in partnership with Indigenous Australian communities.

Microbiome research is currently biased towards populations of European descent, with such populations providing a weak basis upon which to understand microbiome-health relationships in under-studied populations, many of whom carry the highest burdens of disease. Most oral microbiome studies to date have been undertaken in industrialized countries. Research involving marginalised populations should be shaped by a number of guiding principles. In the Indigenous Australian context, one useful framework is the Consolidated Criteria for Strengthening Reporting of Health Research involving Indigenous Peoples (CONSIDER) statement. This paper describes how the microbiome research field is having impacts in the Indigenous Australian health space, and describes a particular project involving Indigenous Australians in which the CONSIDER statement is used as the underlying framework.

Commercializing equitable, accessible oral microbiome transplantation therapy.

Chronic oral diseases, such as caries and periodontal disease, may, in future, be treated by oral microbiome transplant (OMT) technology. OMT therapy would involve collecting a donor oral microbiome and transplanting into a recipient to either prevent or treat oral diseases linked to a change (i.e., dysbiosis) in the oral microbiome. Given the great promise of this technology, we must consider the ethical and practical implications of how it is developed to maximise its accessibility and affordability. Here, we examine ways that OMT technology might be commercialized in the context of equity and accessibility in both clinical or do-it-yourself settings. We do this while assuming that the technology can be developed for humans in ways that are safe and effective at the individual and population-levels. We highlight the need for OMT therapy to be 1) cost-effective, 2) understood by end users and clinicians, 3) easy to access even in rural or remote communities, and 4) providing donors equitable compensation for their microbiomes. These key elements will only be achieved through partnerships between scientists, clinicians, investors and stakeholders throughout development. Therefore, proper acknowledgement and equitable evaluation of contributions in this team will also be critical to ensuring that this technology can be globally accessed. While OMT is likely to reshape how we prevent or treat oral disease, consciously guiding its development toward equity and accessibility to all people may significantly aid in improving health for those without access to dental care.

Oral microbiome research from a public health perspective and implications for oral health.

Advancing oral microbiome research has revealed the association between oral microbiome composition and oral disease. However, much of the research has predominantly focused on comparing health and disease conditions, overlooking the potential dental public health implications. This article examines the evolution of oral microbial research from inception, advancement, and current knowledge of health-associated microbiota. Specifically, we focus on two key aspects: the impact of lifestyle and environmental factors on the oral microbiome and using the oral microbes as a therapeutic modality. The complex interaction of host intrinsic, environmental, and lifestyle factors affects the occurrence and development of the oral microbiota. The article highlights the need for ongoing research that embraces population diversity to promote health equity in oral health research and integrate public health practices into microbiome-based research. The implication of population-level interventions and targeted approaches harnessing the oral microbiome as an intervention, such as oral microbiome transplantation, should be further explored.

Oral health profile of Australian children from different immigrant backgrounds.

OBJECTIVES: To profile the oral health of Australian children from different immigrant backgrounds. METHOD: Cross-sectional data for Australian children were obtained from the 2012-14 National Child Oral Health Study (NCOHS). Three categories of immigrant status were created based on parents' country of birth and language (non-immigrant, non-visible immigrant, and visible immigrant). Descriptive analyses reported weighted estimates for experience of dental caries, self-rated oral health, and dental services utilisation separately for children aged 5-9 years and 10-14 years. RESULTS: The sample comprised 10,610 children aged 5-9 years (3,605 from immigrant backgrounds), and 8,741 children aged 10-14 years (3,074 from immigrant backgrounds). Children from non-visible immigrant backgrounds presented worse dental service utilisation and poorer self-rated oral health than children from non-immigrant and visible immigrant families. Greater inequalities in dental caries experience were observed in the 5-9-year-olds. Untreated caries was substantially higher among visible immigrant children aged 5-9 years (38.8%, 95% CI: 35.5-42.3) than non-immigrant (24.9%, 95% CI: 23.4-26.6) and non-visible immigrant children (21.0%, 95% CI: 17.7-24.7). CONCLUSIONS: Australian children from immigrant families constitute a highly heterogeneous group with substantial discrepancies in oral health outcomes.

Power, dentistry and oral health inequities; an introduction.

Oral health inequities at a global level persist. This is despite marked advancements in technology, service delivery, training, research and population-level initiatives such as water fluoridation. Although the social determinants of health are frequently cited in the framing, analysis and description of oral health inequities, the explicit role of power is usually omitted. Lukes described power as the capacity of actors to make change, as well as to receive and resist change. An analysis of power thus provides a better understanding of how diverse and conflicting interests of multiple actors can lead to differential oral health norms within communities. An analysis of power also demonstrates the intersectional forms of oral inequities experienced among the socially marginalised; it is not rooted in economic deprivation alone. The training and practice of dentistry itself creates intersectional forms of inequalities through race, gender and class. Dental academic spaces are overwhelmingly White, with the knowledge created thus embedded with Eurocentric values. This needs to be challenged. We aim, in this special issue, to provide an overview of the pluralist and diverse nature of contemporary global society, and to show how attempting to impose singular forms of behaviours, values and knowledge that suppress the cultures of socially marginalised communities enhances oral health inequities. Specifically, this special issue will: (1) present an overview of how power operates generally, using implicit bias examples, with a strong underpinning from the literature; (2) describe what this means for power in dentistry, drawing upon sociological literature with a specific lens on dental organisations; (3) expand understanding of post-colonial theory and how this reinforces power structures in dentistry that further enable the privileged and; (4) examine the power relationship between dentists and patients, using theoretical underpinnings and elaborating on different power paradigms in the Australian vs Asian/Korean context.

Oral health-related self-efficacy and fatalism in a regional South Australian Aboriginal population.

OBJECTIVES: To assess the psychometric properties, including face, content, criterion and known-groups validity and reliability, of scales to measure oral health-related self-efficacy and fatalism in a regional Aboriginal adult population in Australia. METHODS: Four hundred Aboriginal adults (aged 18-82 years, 67% female) completed a self-report questionnaire including items pertaining to oral health-related self-efficacy and fatalism. Structural validity was determined in exploratory factor analysis (EFA) with principal components analysis for each scale. Criterion validity was assessed between the instruments and theoretically related variables. Known-groups validity was investigated by comparing the scores in different population groups according to age, sex, education and employment. Reliability of the scales was assessed through internal consistency. RESULTS: The EFA confirmed a single factor structure for self-efficacy and fatalism scales, with Cronbach's alphas of 0.93 and 0.89 respectively. The two scales were not correlated. Oral health-related self-efficacy was associated with toothbrush ownership and brushing the previous day supporting criterion validity. Oral health-related fatalism was associated with previous extractions and perceived need for extractions also supporting criterion validity. Both measures were associated with social impact of oral health as measured by the OHIP-14, supporting their criterion validity. Mixed findings were observed in terms of known-groups validity. CONCLUSIONS: There was initial evidence that measures of oral health-related self-efficacy and fatalism displayed adequate psychometric properties in this Aboriginal community. These constructs could have implications for approaches for improving oral health among Aboriginal people.

Racism and oral health inequities; an introduction.

Contemporary evidence shows that: (i) racial minorities often bear the greatest burden of oral diseases; (ii) there are notable differences between socially advantaged and disadvantaged racial groups and; (iii) racial inequities in oral health persist over time and across space. In the four papers that follow, we seek to contribute to the discourse around oral health and racial inequities through recognition that racism has a structural basis and is embedded in long-standing social policy in almost every developed (and developing) nation. The papers formed the basis of a symposium entitled 'Racism and oral health inequities' at the 99th General Session of the International Association of Dental Research held July 2021 in Boston, United States. The authors responded to the international Black Lives Matter movement that gained momentum in 2019, responding in many calls to arms for greater exposure to the insidious impacts on racism on all facets of health and wellbeing, and the regulatory regimes in which they operate. The papers provide an overview of the history of racism in oral health inequities at an international level, with a specific focus on the implications of addressing (or not addressing) racism in population oral health at an international level. This includes the role of advocacy and engaging with health policymakers to both minimize racism and to increase comprehension of its residual effects that may lead to misinformed policy.

Racism and oral health inequities among Indigenous Australians.

Racial discrimination, which can be structural, interpersonal and intrapersonal, has causal links with oral health morbidity (dental caries, periodontal disease) and mortality (tooth loss). Racism impacts on oral health in three main ways: (1) institutional racism creates differential access to oral health services; (2) cultural racism, which is structurally pervasive, results in poorer psychological and physiological wellbeing of those discriminated against and; (3) interpersonal racism undermines important dental health service provider-patient relationships. Indigenous Australians have experienced sustained racial discrimination since European colonisation in the 1780s. This includes Government policies of land and custom theft, assimilation, child removal and restrictions on Indigenous people's civil rights, residence, mobility and employment. Australia failed to enumerate Indigenous people in the Census until 1967, with the 'White Australia' policy only ending in 1973. In our paper we posit that all minority groups experience racial discrimination that impacts oral health, but that this is amplified among Indigenous groups in Australia because of ongoing legacies of colonialism, institutional racism and intergenerational trauma.

Neoliberalism and Indigenous oral health inequalities: a global perspective.

Neoliberalism is the dominant ideology underpinning the operation of many governments. Its tenets include policies of economic liberalization such as privatization, deregulation, free trade and reduced public expenditures on infrastructure and social services. Champions of neoliberalism claim that expansion of global trade has rescued millions from abject poverty and that direct foreign investment successfully transfers technology to developing economies. However, critics have urged governments to pay greater attention to how neoliberalism shapes population health. Indigenous populations experience inequalities in ways that are unique and distinct from the experiences of other marginalised groups. This is largely due to colonial influences that have resulted in sustained loss of lands, identity, languages and the control to live life in a traditional, cultural way that is meaningful. Oral health is simultaneously a reflection of material circumstances, structural inequities and access to health services. Indigenous populations carry a disproportionate burden of oral health inequalities at a global level. In this commentary, we contend that neoliberalism has overwhelmingly contributed to these inequities in three ways: (1) increased dominance of transnational corporations; (2) privatization of health and; (3) the neoliberal emphasis on personal responsibility.

Making science and doing justice: The need to reframe research on racial inequities in oral health.

This article combines a review of dental studies on race with sociological insights into systemic racism to advance a counter-narrative on the root causes of racial oral health inequities. Taking racism as a form of oppression that cuts across institutional, cultural, and behavioral dimensions of social life, we ask: How pervasive are racial inequities in the occurrence of adverse oral health outcomes? What is the direction and magnitude of racial inequities in oral health? Does the inequitable distribution of negative outcomes persist over time? How can sociological frameworks on systemic racism inform initiatives to effectively reduce racial oral health inequities? The first three questions are addressed by reviewing dental studies conducted in the past few years around the globe. The fourth question is addressed by framing racial oral health inequities around sociological scholarship on racism as a systemic feature of contemporary societies. The paper concludes with a set of practical recommendations on how to eliminate racial oral health inequities, which include engaging with a strong anti-racist narrative and actively dismantling the race discrimination system. Amid the few attempts at moving the field towards improved racial justice, this paper should be followed by research on interventions against racial oral health inequities, including the conditions under which they succeed.

Random and Systematic Bias in Population Oral Health Research: an introduction.

Bias in population oral health research is a form of systematic error that can affect scientific investigations and distort inference (i.e under or over confidence in an estimate). A biased study loses validity in relation to the degree of the bias. While some study designs are more prone to bias, its presence is universal. It is difficult to completely eliminate bias; in the process of attempting to do so, new bias may be introduced or a study may be rendered less generalizable. The goals are to therefore minimize bias and for investigators and readers to comprehend its residual effects, limiting misinterpretation and misuse of data. In the four papers that follow, we seek to contribute to the discourse around random and systematic bias in population oral health research through the lens of case controlled studies, longitudinal studies and genomics re search. The papers formed the basis of a symposium entitled 'Random and Systematic Bias in Population Oral Health Research' at the 98th General Session of the International Association of Dental Research held March 2020 in Washington DC, United States.

DNA replication roadblocks caused by Cascade interference complexes are alleviated by RecG DNA repair helicase.

Cascade complexes underpin E. coli CRISPR-Cas immunity systems by stimulating 'adaptation' reactions that update immunity and by initiating 'interference' reactions that destroy invader DNA. Recognition of invader DNA in Cascade catalysed R-loops provokes DNA capture and its subsequent integration into CRISPR loci by Cas1 and Cas2. DNA capture processes are unclear but may involve RecG helicase, which stimulates adaptation during its role responding to genome instability. We show that Cascade is a potential source of genome instability because it blocks DNA replication and that RecG helicase alleviates this by dissociating Cascade. This highlights how integrating in vitro CRISPR-Cas interference and adaptation reactions with DNA replication and repair reactions will help to determine precise mechanisms underpinning prokaryotic adaptive immunity.

Effects of racism on the socio-emotional wellbeing of Aboriginal Australian children.

BACKGROUND: Racism is a pervasive experience in the life of Aboriginal Australians that begins in childhood. As a psychosocial stressor, racism compromises wellbeing and impacts developmental trajectories. The purpose of the present study was to estimate the effect of racism on indicators of Australian Aboriginal child socio-emotional wellbeing (SEWB) at one to two years after exposure. Age-related differences in the onset of symptoms were explored. METHODS: Data from the B- and K-cohorts of the Longitudinal Study of Indigenous Children were used (aged 6 to 12 years). Racism, confounding variables, and the Strengths and Difficulties Questionnaire (a measure of SEWB) were collected by questionnaires and guided interviews with each child's main caregiver. Adjusted Poisson regression was used to estimate the relative risk (RRa) effects of racism on SEWB for both cohorts separately. RRa were pooled in a random effects meta-analysis. RESULTS: Exposure to racism was associated with an adjusted point estimate indicating a 41% increased risk for total emotional and behavioural difficulties, although the confidence intervals were wide (pooled RRa 1.41, 95% CI 0.75, 2.07). Analyses by cohort showed younger children had higher RRa for total difficulties (RRa 1.72, 95% CI 1.16, 2.54), whilst older children had higher RRa for hyperactive behaviour (RRa 1.66, 95% CI 1.01, 2.73). CONCLUSIONS: The effects observed contributes to our understanding of the impact of racism on Aboriginal Australian children. Support for emotional and behavioural difficulties, and hyperactive behaviour, for Aboriginal children might help counteract the effects of racism. Future longitudinal research and policies aimed at reducing racism in Australian society are necessary.

Transnational corporations and oral health inequalities; an introduction.

In an increasingly globalised world, Trans-National Corporations (TNCs) wield considerable social, economic and political influence, both in the international market economy and within individual countries. The practices of TNCs can have positive or adverse effects on population health through production methods and products, shaping social determinants of health, or influencing the regulatory structures governing their activities. TNCs can contribute to health inequities if the health consequences arising from their practices have disproportionate adverse impacts on vulnerable populations or positive benefits for less vulnerable groups. Despite growing recognition of the implications for health, including oral health, arising from TNC practices, little research has sought to systematically assess the oral health and/or oral health equity impacts of TNCs. In the four papers that follow, we contribute to the discourse around oral health-related inequalities through the lens of power, human agency and TNCs. The papers formed the basis of a symposium entitled 'Transnational Corporations and oral health inequalities' at the 97th General Session of the International Association of Dental Research held June 2019 in Vancouver, British Columbia. The authors responded to the 2014 Lancet-University of Oslo Commission on Global Governance for Health call for greater attention to the health effects of TNC practices and the regulatory regimes in which they operate. The papers overview the role of TNCs in oral health inequalities at an international level, with a specific focus on illuminating their far-reaching influence on our everyday lives, from both epidemiological and sociological perspectives, and the multi-faceted positive or adverse effects on oral health this might have. Key TNC examples are provided by way of the sugar and the tobacco industries, with their impact on dental caries, periodontal diseases and head and neck cancers.

Political economy, trade relations and health inequalities: lessons from general health.

OBJECTIVES: This article argues that health outcomes, specifically nutrition related health outcomes, are socially determined, and can be linked to a wider political economy in which peoples' dietary consumption is structurally determined, evolving from political, economic and social forces. The article examines trade and investment agreements as regulatory vehicles that cultivate poor dietary consumption and inequalities in health outcomes between and within countries. How does this happen? The liberalization of trade and investment, and unfettered influence of powerful economic interests including transnational food and beverage companies has resulted in trade agreements that enable excess availability, affordability and acceptability of highly processed, nutrient poor foods worldwide, ultimately resulting in poor nutrition and consequently oral and other non-communicable diseases. These trade and nutrition policy tensions shine a spotlight on the challenges ahead for global health and development policies, including achievement of the Sustainable Development Goals.

Confirmatory factor analysis of the health literacy in dentistry scale (HeLD) in the Australian population.

OBJECTIVE: To determine the psychometric properties of both the long- and short-form versions of the Health Literacy in Dentistry (HeLD) instrument in a large sample of the Australian adult population. METHODS: Data were from a subset of the National Dental Telephone Interview Survey 2013. Both the long (HeLD-29) and short-form (HeLD-14) were utilised, each of which comprises items from 7 conceptual domains: access, understanding, support, utilization, economic barriers, receptivity and communication. Confirmatory Factor Analysis was performed through structural equation modelling to determine factorial validity, where the Χ²/df, comparative fit, goodness of fit and root mean square error of approximation were used as indices of goodness of fit. Convergent validity was estimated from the average variance extracted (AVE) and composite reliability (CR), while internal consistency was estimated by Cronbach standardized alpha. RESULTS: The dataset comprised 2,936 Australian adults aged 18+ years. The kurtosis and skewness values indicated an approximation to a normal distribution. Adequate fit was demonstrated for HeLD-14, but not for HeLD-29. Estimates of ≥ 0.50 for AVE and ≥ 0.70 for CR were demonstrated across all factors for both HeLD-29 and HeLD-14, indicating acceptable convergent validity for both forms. Discriminant validity was also demonstrated for both forms. Internal consistency was adequate in the seven conceptual domains for both HeLD forms, with Cronbach's alpha for all subscales being ≥0.70. CONCLUSIONS: The psychometric properties of the HeLD instrument in a large sample of the Australian adult population were confirmed. The short form HeLD-14 was more parsimonious than the long-form (HeLD-29).

Changes in elevated cholesterol in the era of tenofovir in South Africa: risk factors, clinical management and outcomes.

OBJECTIVES: Antiretroviral therapy (ART) has been associated with unfavourable lipid profile changes and increased risk of cardiovascular disease (CVD). With a growing population on ART in South Africa, there has been concern about the increase in noncommunicable diseases such as CVD. We determined risk factors associated with increased total cholesterol (TC) in a large cohort on ART and describe the clinical management thereof. METHODS: We conducted an observational cohort study of ART-naïve adults initiating standard first-line ART in a large urban clinic in Johannesburg, South Africa. TC was measured annually for most patients. A proportional hazards regression model was used to determine risk factors associated with incident high TC (≥ 6 mmol/L). RESULTS: Significant risk factors included initial regimen non-tenofovir vs. tenofovir [hazard ratio (HR) 1.54; 95% confidence interval (CI) 1.14-2.08], age ≥40 vs. <30 years (HR 3.22; 95% CI 2.07-4.99), body mass index (BMI) ≥ 30 kg/m2 (HR 1.65; 95% CI 1.18-2.31) and BMI 25-29.9 kg/m2 (HR 1.70; 95% CI 1.30-2.23) vs. 18-24.9 kg/m2 , and baseline CD4 count < 50 cells/µL (HR 1.55; 95% CI 1.10-2.20) and 50-99 cells/µL (HR 1.40; 95% CI 1.00-1.97) vs. > 200 cells/µL. Two-thirds of patients with high TC were given cholesterol-lowering drugs, after repeat TC measurements about 12 months apart, while 31.8% were likely to have received dietary counselling only. CONCLUSIONS: Older age, higher BMI, lower CD4 count and a non-tenofovir regimen were risk factors for incident elevated TC. Current guidelines do not indicate regular cholesterol testing at ART clinic visits, which are the main exposure to regular clinical monitoring for most HIV-positive individuals. If regular cholesterol monitoring is conducted, improvements can be made to identify and treat patients sooner.

Periodontal therapy and glycaemic control among individuals with type 2 diabetes: reflections from the PerioCardio study.

OBJECTIVES: Diabetes mellitus and periodontal disease are highly prevalent among Indigenous Australian adults. Untreated periodontitis impacts glycaemic control in people with diabetes. The aim of this study was to report on the effect of periodontal therapy on glycaemic control among people with obesity. METHODS: This subgroup analysis is limited to 62 participants with diabetes from the original 273 Aboriginal Australian adults enrolled into the PerioCardio study. Intervention participants received full-mouth non-surgical periodontal scaling during a single, untimed session while controls were untreated. Endpoints of interest included change in glycated haemoglobin (HbA1c), C-reactive protein (CRP) and periodontal status at 3 months post-intervention. RESULTS: There were more females randomized to the treatment group (n = 17) than control (n = 10) while the control group had a higher overall body mass index (BMI) [mean (SD)] 33.1 (9.7 kg m-2 ) versus 29.9 (6.0 kg m-2 ). A greater proportion of males were followed up at 3 months compared to females, P = 0.05. Periodontal therapy did not significantly reduce HbA1c: ancova difference in means 0.22 mmol mol-1 (95% CI -6.25 to 6.69), CRP: ancova difference in means 0.64 (95% CI -1.08, 2.37) or periodontal status at 3 months. CONCLUSIONS: Non-surgical periodontal therapy did not significantly reduce glycated haemoglobin in participants with type 2 diabetes. Reasons are likely to be multifactorial and may be influenced by persistent periodontal inflammation at the follow-up appointments. Alternatively, the BMI of study participants may impact glycaemic control via alternative mechanisms involving the interplay between inflammation and adiposity meaning HbA1c may not be amenable to periodontal therapy in these individuals.