BIBLIOTECA MUNICIPAL

Edentulism is defined as complete tooth loss. This means that all 28 natural permanent teeth (excluding wisdom teeth) are missing. It has been termed the “dental equivalent to mortality” (Weintraub and Burt, 1985) and is considered the final marker of oral disease burden (Cunha-Cruz et al., 2007). As such, it acts as both a marker of oral disease as well as its poor management (U.S. Department of Health and Health Education and Welfare, 1960). This makes it a useful focus when monitoring oral health of populations throughout the world (Hobdell et al., 2003). In Ireland, for example, policy makers had set a target of reducing the proportion of adults over 65 years of age who are edentulous to less than 42% of the population by the year 2000 (Department of Health, 1994). In fact, Ireland used this target to shape services and in 2000/2002 the proportion over 65 years of age who are edentulous was 41%. This represented a drop from 72% self-reporting edentulism in 1979 (Whelton et al., 2007).

Internationally, rates of edentulism are heading in the right direction: the proportion of adults with total tooth loss is reducing (Beltran-Aguilar et al., 2005, Polzer et al., 2010, Kassebaum et al., 2014). After a dramatic decline decade-on- decade, the prevalence of edentulism among the adult population internationally sits somewhere between 2% and 8%, in recent studies (Beltran-Aguilar et al., 2005, Medina-Solis et al., 2008, Slade et al., 2014, Kassebaum et al., 2014), but somewhat higher in lower income countries (Kassebaum et al., 2014, Tyrovolas et al., 2016). These prevalence data are known to vary significantly across sociodemographic

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circumstance, such as education, occupation, smoking status, gender, race, health, level of dependency, background and place of living, with increasing age being a very strong predictor of complete tooth loss (Kelly et al., 2000, Österberg et al., 1995, Müller et al., 2007). Incidence of tooth loss increases dramatically in the seventh decade (Kassebaum et al., 2014) and as seen in Chapter 1, this population is set to boom. So, despite the decline in the edentulous proportion, the demographic reality of population aging ensures that edentulism, and its precursor partial edentulism, will be prevalent for years to come.

Similar to the general population, there is value in identifying the rate of edentulism among the population with ID as a measure of oral disease burden and the appropriateness, or not, of dental disease management over time. Such data would allow appropriate planning, policy and monitoring within this population. In addition, such data would allow a measure of comparison between the general population and those with ID, who are often excluded from epidemiological research. This would highlight health disparity if such a phenomenon exists. Therefore, in this section we review the available literature to identify the proportion of people with ID who are edentulous. However, before exploring the results of this literature review, it is salient to consider, briefly, the causes of edentulism among people with ID.

2.2.1.1 Background: Causes of total tooth loss in intellectual disability

Edentulism represents a cumulative end-point of successive tooth loss. So, to understand edentulism, one must first consider tooth loss. The literature is unambiguous that tooth loss is more common in adults with ID than the general population (Cumella et al., 2000, Donnell et al., 2002, Gabre et al., 1999, Shaw et al., 1990, Tiller et al., 2001). This is true across all reporting standards: Between 33% and 63% of people with ID have at least one missing tooth (Shapira et al., 1998, Lopez del Valle et al., 2007, Fernandez Rojas et al., 2016) and the mean number of teeth missing (either in total or as the Missing component of DMFT index[Total of the Decayed, Missing and Filled Teeth], which under-reports tooth loss because it considers caries-related tooth loss only) lies between 3 and 28 missing teeth for adults with ID (Lindemann et al., 2001, Morgan et al., 2012, Pregliasco et al., 2001, Tiller et al., 2001, Seirawan et al., 2008).

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The number of missing teeth has been found to accrue with age. Tooth loss may be minimal among healthy adults with ID in their early twenties (Fernandez Rojas et al., 2016). Turner, found that older athletes, those over 35 years of age, were more likely to have missing teeth than their younger peers (Turner et al., 2008). Likewise, Petrovic et al., in a contemporary study, found more missing teeth in older people with ID attending specialist clinics (Petrovic et al., 2016). An Italian study, in 2001, demonstrated a stark relationship between tooth loss and age. In this study, most untreated caries was found in middle age, while the mean number of missing teeth (MT) rose from 6.6 in early adulthood to 23-28 in those over 55 years of age (Pregliasco et al., 2001). In Ireland, similar trends were noted by Crowley et al. who found a sharp increase in tooth loss with age among institutionalised adults with ID; particularly over 55 years of age (Crowley et al., 2005).

Tooth loss is influenced by psychosocial, economic, environmental and political circumstance (Watt, 2007). However, this element is outside of the scope of this discussion. In this study we focus on caries and periodontal disease because, together, they account for almost 95% of tooth loss among adults with ID (Gabre et al., 2002, Gabre et al., 2001, Gabre, 2000, Gabre and Gahnberg, 1994). Both are highly prevalent, chronic conditions associated with dental plaque, which tend to have cumulative impact on oral health, potentially leading to successive tooth loss if not managed appropriately. Therefore, tooth loss represents a complex interplay of an individual’s history of dental disease and its treatment by dental services over the life course (Kassebaum et al., 2014). Gabre and colleagues undertook longitudinal analyses among adults with ID in a range of residential settings, to explore reasons for tooth loss. They found that dental caries and particularly periodontitis accounted for 37.3% and 57.4% of tooth loss, respectively (Gabre et al., 2001).

The prevalence of dental caries in populations with ID is considered similar or sometimes slightly lower than that in the general population (Anders and Davis, 2010). However, its sequelae are different within these groups. For adults with ID, dental caries is often untreated. Research shows that between 21% and 82% of adults with ID were found to have untreated caries (Petrovic et al., 2016, Oliveira

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et al., 2013, Morgan et al., 2012, Fernandez et al., 2012, Oredugba and Perlman, 2010, Reid et al., 2003, Cumella et al., 2000, Shapira et al., 1998, Seirawan et al., 2008) and when treated, this was often by extraction rather than filling (Petrovic et al., 2016, Oliveira et al., 2013, Costello, 1990). Adults with ID, living in the community, demonstrate a tendency for higher levels of untreated caries and less treatment by extraction than those in institutions (Kendall, 1991, Gabre, 2000, Tiller et al., 2001), meaning that they are probably not receiving treatment of caries as often as their institutionalised counterparts.

People with ID are also found to have a greater prevalence of periodontal disease than the general population, ranging from 44% to 59% of samples reporting periodontal disease; while the prevalence of gingivitis (inflammation of the gum and associated tissues) can be as high as 95% (Fernandez Rojas et al., 2016, Morgan et al., 2012, Schulte et al., 2011, Oredugba and Perlman, 2010, Cumella et al., 2000, Naidu et al., 2001). The severity of this disease is also worse among adults with ID. In Ireland, 6.3% of 35-44-year- olds had deep pocketing around teeth (CPITN index score of P2), compared to 45% in people with intellectual disability aged 35-54, who had moderate/severe periodontal disease (Whelton et al., 2007, Crowley et al., 2005). While different indices were used to record these data, suggesting caution in comparison, the difference is stark. In Australia, for example, periodontitis was five times more prevalent among adults with developmental disabilities (Scott et al., 1998). Institutionalised persons and those with more profound ID are found to have higher levels of periodontal disease or gingival inflammation (Petrovic et al., 2016, Cumella et al., 2000, Kendall, 1992).

This introduction demonstrates that edentulism represents the final outcome of cumulative tooth loss, due predominantly to periodontal disease and caries, where effective prevention and/or treatment have not been achieved and that the underlying diseases and poor treatment decisions, that promote edentulism, are prevalent among adults with ID.

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