Poor oral health in older adults is a neglected and intractable problem, impacting on overall health and wellbeing of the older adults. It can affect their quality of life in many ways, including limiting the pleasure of eating, because of reduced chewing capacity with resultant malnutrition, feeling ashamed of dentures, and association with diabetes and mental health [2,3,4]. It can increase hospital admissions related to poor dental care such as aspiration pneumonia and dental care under general anesthetic as well as the broader impact of dental problems including malnutrition and falls [31,32]. Additionally, there is an increase in polypharmacy and medications’ use with side effects of xerostomia resulting in an increased risk of oral diseases such as dental caries [33].

There is also the impact on dental treatment required. Barriers to optimal care include lack of specific training for dental professionals and aged care staff [19,20,21], overcoming patient fears related to past experiences of oral care [22], family attitudes to oral care [23] and lack of understanding of the importance of oral care and cost of and access to dental services [24,25].

Firstly, it is important to explore the concept of ROHD in older adults [11,34]. It is important both dental professions and other relevant professions and carers understand and can identify ROHD. There is limited but important work in the literature looking at measures of ROHD in older adults [11,35]. Meanwhile, the term “rapid deterioration of oral health” or “rapid oral health deterioration” has been used in various research articles—some of that work is not relevant here—such as when used in another age group or a particular context.

Prior to examining the factors associated with poor oral health, particularly ROHD, it is important to consider what is happening in older adults at a more systemic level. Whether oral health is impacted or not is associated with the individual’s ability to care for themselves and their mobility to access oral health care. The physiology of ageing can be characterized by the progressive loss of physiological integrity, resulting in impaired function and increased vulnerability [36]. All of these can result in the development of a set of unifying pathological conditions of geriatric syndrome [37,38]. This syndrome is a complex relationship between multimorbidity, polypharmacy and frailty that can contribute to poorer oral health outcomes [33]. It can be used as a framework for addressing the complex oral health needs of older adults and the presentation of common geriatric oral syndromes [33,39]. A complex array of shared risk factors (e.g., increased age, cognitive impairment, functional impairment and impaired mobility) can result in the traditional geriatric syndrome (incontinence, falls, pressure ulcers, delirium and functional decline) and may be influenced by multi-morbidities (e.g., diabetes, neurodegenerative disorders, Alzheimer’s/dementia and cardiovascular disease), polypharmacy and resultant frailty [33,39]. All of which have an impact on oral health with the presentation of a common set of symptoms (geriatric oral syndrome) such as burning mouth syndrome, xerostomia, dental caries, periodontitis, dysgeusia, dysphagia and dyskinesia/dystonia [33,39]. Ní Chróinín and colleagues found that poor oral health in older adults was associated with Alzheimer’s disease and kidney failure—even when adjusted for medication and salivary pH [6]. Therefore, in addressing the oral health of an older adult, it will mean developing a preventive and management strategy that takes into consideration the impacts of the presence of geriatric syndrome as well as in the broader context of SDH. So, in understanding ROHD, geriatric syndrome may be part of the pathway in which SDH can influence ROHD.

There are at least two ways we could explore this topic. Firstly, we could determine changes in oral health (with appropriate measure for dental caries, periodontitis, tooth loss, etc.) in older adults with longitudinal studies of older adults (potentially concurrent with regular dental appointments) with associated data on SDH. Unfortunately, there are limited cohort data on older adults and a dearth of dental data. Collecting such data may be costly (without good administrative systems) and require some time, however this would be valuable longer term, especially if population-based and linkable with broader administrative data to help identify SDH [14]. Thus, it is more feasible that we could consider likely pathways for ROHD in older adults by reviewing the existing literature on oral health determinants more broadly. Consideration of the social gradient and inequalities in oral health may help further determine the specific factors disadvantaging older adults to target preventative oral health measures including policies and practices.

Frailty is an important consideration in terms of risk for ROHD, although with varied definitions, and work on frailty and oral health is still very much in progress [40]. One group at particular risk of ROHD are older adults with dementia [41]. We know generally that people with dementia have poorer access to dental services and poorer oral health outcomes than other older adults [42].

It is important that both dental professions and other relevant professions understand and can identify ROHD as a precursor to understanding the influence of social determinants. There is limited but important work in the literature looking at measures of ROHD in older adults [11,35]. Marchini and colleagues have developed a teaching tool to establish risk of ROHD in older adults and this was found useful in teaching geriatric oral health for dental students over a number of years [11,35]. It would be useful if such tools were considered for wider use in dental teaching.

Influences on oral health in older adults, including ROHD, are complex and affected by a range of social, heath and clinical factors. We will focus here on the social determinants. If we consider the impact of SDH on oral health, their importance is evident, although substantial work remains before obtaining a full understanding of the relationships between SDH and oral health in older adults and a translation of the findings. The SDH are underpinned by social justice. There is a substantial social justice issue when our older adults are impacted in terms of pain, poor ability to eat properly with reduced pleasure in eating and subsequent effects on wellbeing (including social isolation due to reduced social interactions because of embarrassment, shame, reluctance to smile because of their oral health status) because they are not receiving adequate dental care, this being worst in the more marginalized groups [1]. There are a number of pathways through which disadvantage in terms of social determinants impacts on oral health outcomes. Dental attendance is often affected and our own work using population level data from a national survey, shows that lower dental attendance is strongly associated with older age, less schooling, lower wealth and higher measures of disadvantage [5].

While Fisher-Owens et al. developed a model regarding oral health in children (with influences from Bronfenbrenner’s work) some of the principles could be applied here [28,43]. Adapting Fisher-Owens, we could have the following categories of influences (see Table 1) [28].

These influences do not fully address what occurred at different points during the life-course but instead largely reflect the current situation in relation to older age and ROHD. There also may be several overlaps between the different influences such as health behaviors that are part of both older adult and family as these key influences are linked to the environment and characteristics.

The problem of ROHD is complex and it is likely that multiple approaches will be required to deal with the problem. Watt has identified the importance of upstream action in oral health [25]. Successful prevention could potentially mean more people with intact teeth and limited restorations, but this may take generations. Broader upstream actions include addressing social determinants more broadly. Education has strong socio-economic impacts on oral health outcomes. This would likely also apply in terms of impacts on ROHD. In addition, developing better integrated primary care for older adults, ideally with inclusion of a dental professional but also with skills in non-dental professionals to identify and predict this disorder. This is important as many older adults do not see a dental professional regularly [5].

We have limited dental professionals with appropriate training in dental care for older adults; in fact, in many countries we still have limited training in geriatrics for dental students. Slack-Smith et al. have noted the limited emphasis on geriatric dentistry in dental courses in Australia and others similarly overseas [44]. The current model of dental care, which largely depends on ad hoc access to a limited supply of public and private dentists working in residential aged care sector is clearly not adequately addressing this problem in Australia.

Due to such complexity of the interplay of risk factors, comorbidities, polypharmacy and frailty, the complexity of oral health management for these individuals increases. The health outcomes of frailty come with increased risk of falls, disability, dependency and death [45]. Therefore, it will be important to identify any determinants that could indicate that the individual is at the precipice of decline so that oral health interventions can occur with adequate timing and prior to any occurrence of ROHD. This is particularly important in the case of older adults in high-dependency residential facilities as these individuals are at the greatest risk of rapid health decline and by extension oral health decline. It is this identification of the window of opportunity that is currently elusive to dentistry.

One way of identifying the time frame in which oral health assessment, prevention and intervention can occur is utilizing the tools that consider factors of SDH. These are factors that can be assessed by non-dental professionals. As such, they can then give a quantifiable indication in which these determinants can then trigger a referral to an oral health care professional for further oral health assessments that may be required in the context of an expected deterioration in health as well as the level of oral health care intervention that is most suitable for the expected trajectory of the individual. This modality of assessment and care intervention looks at oral health in terms of not a disease but as a form of holistic care that puts the patient at the center of care.

Additionally, the concept of the Geriatric 5Ms of: mind, mobility, medications, multi-complexity and matters most can be used as a framework in the oral health management plans of older adults [46]. These 5Ms are domains in which they allow the consideration of functional status, medication reviews, careful evaluation of risks and benefits of treatment, assessment of goals of care as well as prognosis of the patient’s condition to be incorporated into the overall management and comprehensive treatment planning of the older adult [46]. They consider the patient in a holistic manner and put the patient’s beliefs and values at the center of care. Thus, the 5Ms allow management to be patient centered and not disease centered.