Inequity and disparity in oral health-Part I: a review of oral health status measures.ABSTRACT
While overall, the oral health of Canadians has improved according to several outcome measures, on closer inspection a widening gap exists between those with the highest oral health status and those who are the least healthy orally. This is largely due to the socio-economically advantaged having substantial improvements in their oral health status while the less advantaged are not realizing similar gains. The resulting disparities are not unique to oral health, and are also evident in general health. The reasons for the polarization in oral health status are complex and require sophisticated, multidimensional strategies to mitigate them.
This paper provides an overview summarizing the literature about various oral health status measures and will begin to illustrate the oral health disparities that exists in several sub population groups of Canadians. Both traditional clinical oral health measures, and the more subjective psychosocial measures are included in the review. The former measures include dental care utilization rates, caries experience, periodontal measures, tooth loss and oral lesions, while the latter measures include quality of life and oral satisfaction measures.
While this review focuses on the various measures used to assess oral health, it will introduce such population groups as First Nations, new Canadians, seniors, socio-economically disadvantaged, remotely located and institutionalized that collectively demonstrate lower oral health status than less marginalized Canadians. The status quo in oral health care delivery has benefited many Canadians, but it has left a significant proportion without comprehensive care, and subsequent poorer oral health.
Part II of this paper, to be published later, will describe the various exposure variables operating as contributing factors and casual forces for the outcome measures described here. This subsequent review will also provide an exploration into potential impact the dental hygiene profession could make in assuaging these disparities.
Key words: oral health, inequities, disparities, dental hygiene, care
The oral health status of Canadians varies across the population with less advantaged population groups displaying lower oral health status than others. (1), (2) This variation among groups is a result of numerous forces including inequities in oral health care delivery. this phenomenon is not new, but disparities in oral health status have become increasingly glaring. (3)
The philosophy of Canada's health care system denounces inequities in health care, and yet inequities persist in oral health care, which has largely embraced a free market economical structure in its delivery. Because of the lack of structures that support access to care, the current system of oral health care delivery virtually ensures a marked polarization in oral health care delivery virtually ensures a marked polarization in oral health status between the most advantaged and most disadvantaged population groups. For those that believe oral health is part of overall health, the dichotomy between the two population groups creates a tension.
In response to this discord, many oral health researchers and professional groups have suggested a reorientation of oral health care delivery. Dental hygiene through its national professional organization, Canadian Dental Hygienists Association (CDHA), has publicly identified its view of the failure of the oral health system and has positioned itself against the inequitable distribution of oral health care. (4) Further to CDHA's critical stance has been its assertion that the dental hygjene profession has great potential to make an impact on oral health inequities but has largely been prevented due to structural factors primarily surrounding restrictive legislation and funding mechanisms. (4) These factors, which will be discussed in Part II of this paper, prevent the public from directly accessing dental hygiene care and perpetuate a reliance on the traditional model of oral health care delivery. Removal of such restrictions would allow dental hygiene practitioners to provide primary care in alternative settings, thus promoting access and attenuating the widening disparities in the oral health status of Canadians. (4), (5)
The aim of Part I of this paper is to provide a summary of the literature about various oral health status measures. Through this orientation to oral health measures, the reader will be introduced to oral health disparities existing in Canadian sub-population groups.
Materials and Methods
A literature search was conducted of the MedLine data base from 1963 to September 2008, and Google Scholar using the following key words and their combinations: oral health, status, inequities, disparities, dental hygiene, care, Canadian. Of the articles generated by the initial search, based on titles and abstracts, sixty-five were retrieved in full text. Additional papers were located utilizing these references and also searching key authors in this field of inquiry. This search is not to be considered exhaustive.
Universal health care has not lost its relevance to global society as it is still high on the policy agenda for many developed nations. (6) In Canada, support for universality and the provision of equitable and accessible basic health care services continues to be favoured. (3) Where the discourse gets confusing is in what is considered "basic", and whether oral health care falls within this realm. (6) As researchers continue to uncover more of the web of factors that contribute to morbidity and mortality, expectations surrounding quality of life and broader conceptualizations of health develop further. Recent perceptions on health care have become more comprehensive, (6) and support for the inclusion of previously excluded services, including oral health care have increased.
The dental profession has been described as being at a crossroads, determining what theoretical underpinning will guide its practice in the next decades. (6) While it appears that dental care in Canada and the US is increasingly based on a neo-liberalist standpoint with the free market economy guiding practice, in an alternate view such as that of the Canadian health care system, dentistry and oral health care are founded on "contractarianism"6 where inevitable social inequalities are managed fairly with basic needs more equitably distributed across the population. Dharamsi (6) describes this latter scenario being closely related to "distributive justice" where, on moral grounds, the allocation of resources is socially justified while ensuring that providers are fairly compensated and that the population receives a "reasonable" share of services.
The philosophical perspective that grounds professional practice is important because it influences the stance it takes with government and others in helping shape public policy. Dentistry may appear to display some philosophical confusion between its moral values to society on the one hand and its commercial values of practice on the other. (6) CDHA has made its ideology clear in stating on its web site, "The CDHA is dedicated to the principle that all Canadians should have access to quality preventive oral health services provided by dental hygienists. The CDHA seeks input from and dialogue with government and consumers to enable it to serve more effectively both its members and the Canadian public." (7)
Given organized dental hygiene's philosophical position, it is essential to clarify the status of Canadians' oral health and what (if any) inequities have contributed to it. While the literature about inequalities in health care distribution and outcomes is not extensive, it does provide compelling evidence that less advantaged groups have poorer oral health outcomes. (1-3) While no agency in Canada is obligated to report oral health inequities, (3) it is becoming apparent that oral health disparities are becoming increasingly pronounced, meaning that the gap between the oral health of the most and least advantaged Canadians is widening. (3), (8) This is disappointing, and possibly surprising, to many Canadians who enjoy at least satisfactory oral health, and are unaware of the many sub-population groups that have been unable to access care and have been left vulnerable to unmet needs and subsequent poor oral health. (8-10)
While determining a clear picture of the current burden of oral illness is essential," Leake3 reports that the Canadian public health system has not adequately measured the population's oral health, and that there is lack of adequate surveillance systems consistent with international standards (3) The need to collect data on the oral health of Canadians has been raised by such groups as CDHA (7) and the Federal/Provincial/Territorial Dental Working Group (FPTDWG). (12) The last national survey was conducted in the early 1970s; thus, current information regarding Canada's oral health status and trends are lacking. (13) The development of a Canadian Health Measures Survey sampling 5000 Canadian children and adults addresses this lack. The survey is targetted for implementation in 2010 and includes several oral health measures. (14)
ORAL HEALTH STATUS MEASURES
While traditional methods of measuring oral health status have relied on clinical or biophysical measures such as caries measures, and tend to be more unidimensional, recent emphasis has focused on psychosocial models, such as oral health satisfaction. (10), (11), (15) These more recent measures are in alignment with contemporary ideas about health and are typically used to supplement clinical outcome measures. (10), (11), (15)
Interestingly, only some associations were found between clinical indicators and more subjective oral health scales. (11) Locker explains the lack of agreement in that psychosocial measures are influenced by individual experience and functional variables. (11) Based on the World Health Organization's (WHO) generic model, Locker developed a conceptual framework of oral health that utilizes not only biophysical impacts and social concerns, but also such intermediate influences as functional limitations, pain or disability. (11) Clearly, contemporary ideas for describing oral health status require a balance of both objective, clinical, and subjective psychosocial measures.
Objective oral health status measures
Objective oral health clinical measures for instance, caries, periodontitis, edentulousness, and prosthetics, have been measured the most extensively, and these will each be discussed in turn. Utilization rates or dental visits, as an oral health status measure, have also been used in that they are seen to relate directly to access. However this relationship requires the assumption that greater utilization is equivalent to oral health improvements. Thus, care is commensurate with need. (9), (16) However, in fee-for-service environments, considerable variance occurs as a result of various influences including inappropriate provision of care (over-use), and these implications must be considered when examining utilization rates.
In the least advantaged groups there does appear to be value to measuring utilization rates. Leake (3) reports that socio-economic status effects dental visiting, and those needing care the most are least likely to receive it. This phenomenon, termed the "inverse care law", (3) has been demonstrated with the elderly and other such disadvantaged groups as the poor, medically compromised, less educated, institutionalized and ethnic minorities. (17), (18) Lower rates of utilization have been associated with high caries rates in elderly populations. (9). Conversely, long term care residents who regularly use oral health services have been shown to have superior oral health than their contemporaries who do not use similar services. (19) The type of utilization is also important; for example, accessing care only when in pain versus care for prevention or maintenance is associated with higher levels of disease, and more specifically, with tooth loss. (20) In the US, about 25 per cent of the population seeks out dental care only in emergency situations. (6)
One of the most prevalent outcome measures of oral health status is caries rates. Bacterial plaque accumulation has been shown to be a significant factor in explaining caries, and plaque indices are associated with socioeconomic status. (21) By adulthood, almost everyone has experienced tooth decay, but caries rates are considerably and unequally distributed across the population with lower socio-economic groups demonstrating a disproportionately greater experience. (8) While caries is nearly ubiquitous, most incidence occurs in childhood, adolescent, and senior years. Caries rates have continued to decline in the last fifty years, but certain sub-populations have considerably higher levels of disease prevalence and severity including First Nations and Inuit children, children born outside of Canada, and seniors. (3), (22)
Early childhood caries is an aggressive form of caries marked by early disease experience (one or more primary teeth affected in infants less than 72 months old) and multiple contributing factors. (23) Severe forms require treatment by pediatric dental specialists in hospital settings under general anesthesia, (23) often incurring substantial travel and treatment costs. Full mouth extractions can be the outcome of severe early childhood caries leaving very young children physically and emotionally debilitated. Recently, it has been shown that socio-economic status is one of the most important associations with early childhood caries while poor oral hygiene and sugar consumption also present increased risk. (23) Additionally, limited access to professional oral health care, feeding practices and other factors may be involved. (23)
First Nations populations have consistently demonstrated an extremely high prevalence of early childhood caries; Manitoba, Ontario and British Columbia demonstrated proportions of 50%-100% compared to 5 per cent seen in general populations. (22), (23) While caries rates in First Nations' child populations have shown recent decline, improvements have only been evident in permanent teeth, and caries rates remain higher than in other children of the same age and region. (22) Harrison and Davis (22) explained that the lack of improvement in primary teeth was due to a lack of exposure to school based preventive programs until after caries had been initiated.
While in other populations less is known about the prevalence of early childhood caries, in a recent Manitoban pilot study (23) using an agricultural, rural three-year old Caucasian population exposed to fluoridated water, early childhood caries was demonstrated in 44 per cent of the children with 21 per cent demonstrating severe early childhood caries. In this study, caries experience was inversely associated with maternal education levels. (23) While family size was also a factor, its influence was not attributed to reduced financial resources but rather more likely to time constraints, as plaque and oral debris levels were also found to be high. (23) Almost half of the study subjects had not yet visited a dentist, and the authors concluded that earlier attendance had been warranted. (23)
While caries experience typically tapers off considerably once reaching adulthood, a re-emergence of the disease occurs in late adulthood often in the form of root caries. More older adults are retaining their teeth longer, and as a result, it is expected that root decay will be an increasingly significant problem. (18), (24) Studies have demonstrated root caries prevalence of up to 90 per cent of elderly people, (9), (18), (24) and a shift has shown that the ratio of decayed to filled teeth has increased in favour of decay. (9)
Along with caries, periodontal disease contributes substantially to oral tissue destruction and eventual tooth loss. Recognizing that epidemiological studies are believed to underestimate periodontal disease experience because they include healthier individuals with somewhat intact dentitions and utilize more conservative diagnostic criteria, severe periodontal disease is believed to be less prevalent than once thought. (25), (26) However, there are some population groups that are disproportionately affected, (25), (26) and the prevalence and severity in these groups may be increasing. (27) Utilizing multivariate analysis, periodontal disease has been shown to be associated with social and behavioural factors. (26) More specifically, variables such as older subjects, smokers, those with fewer teeth, those with less education, and those who do not make regular dental visits were all found to be important with the first three variables having the most consistent associations with periodontal disease. (26)
Edentulousness (toothlessness) represents the ultimate poor oral health outcome, and is a commonly used indicator of dental health status particularly in older populations. (20), (27) While in the last national study more than half of Canadians over sixty years of age were found to be edentulous. (13) North Americans have demonstrated significant declines in edentulousness in older groups, albeit with disease shifting to increases in caries and periodontitis. (27) Clovis (8) reported in the 1990s that approximately one third of all Canadians over 65 years have lost all of their teeth. In more recent provincial studies, edentulousness rates have varied from 51%-81% in those over 65, (l3) with independent seniors having lower rates than the institutionalized elderly. (18), (28)
Tooth loss, especially complete tooth loss, is extremely significant to health and well being. Leake (13) states that the presence of one's natural teeth is the single strongest predictor of maximal oral function. Edentulous individuals report gastrointestinal problems often requiring medication when dentures cannot be adequately fitted. (8) While little documented data exists on the psychological and social impacts of tooth loss, Miller (20) asserts that in comparison to other life events, edentulousness must be considered to require considerable adjustment with substantial functional, social and psychological problems. Tooth loss and edentulousness are positively related to disadvantaged population groups and are associated with all classic socio-economic status measures and minority status. (9), (10)
In an attempt to diminish the affects of the loss of some or all teeth, oral prosthetics are often fabricated but are often a less than ideal replacement of the natural dentition. In a review that included Canadian data, it was reported that 6 per cent of the residents in a long term care institution wore their dental prosthesis only for meals or when receiving visitors, and 20 per cent reported dissatisfaction with their dentures. (18) Increasing prosthetic needs are associated with the elderly as they experience more tooth loss. (27)
Soft tissue lesions and cancer are other outcome measures that have been used to assess oral health status. Some studies indicate that 30 per cent of seniors will experience non cancerous soft tissue lesions with a greater prevalence in those residing in long term care institutions. (18), (29) These lesions may vary from asymptomatic to painful and potentially serious, and many relate to ill-fitting dentures. Oral cancer can be painful, disfiguring and often deadly. Clovis (8) reported that one in fifty cancer deaths in Canada and the US were attributed to oral cancer. Oral cancer is often overlooked until it has reached more advanced and less treatable stages. (8) Older adults are disproportionately affected with almost linear associations between lip, tongue and intra-oral cancers and increasing age, albeit a slower progression with the last two. (8) Smoking and alcohol consumption, particularly when in combination, are both well known risk factors. (17)
Subjective oral health status measures
Subjective oral health status measures are increasingly recognized as important indicators of oral health and wellness. Examples of these measures include self perceived oral health, and oral health related quality of life. (10), (30), (31) These measures have been described as complex and multidimensional constructs, and are considered subjective in that they are based on the individual's perceptions of oral wellness. (31) Criticisms have sometimes centred on the lack of agreement between subjective measures and more traditional, objective measures. However, more recent studies have shown strong associations between subjective and objective measures improving the validity of such measures. (31)
The measurement of one's quality of life is a relatively recent outcome measure pertaining to oral health status and can include a number of other more subjective, psychosocial measures. Locker identified problems surrounding quality of life measures including their lack of use and that, when used, studies inherently report the experience of "healthy survivors". (30) However, inroads have been made in developing and validating quality of life composite scales and measures. Through these measures, it is possible to determine if and to what extent oral disease impacts function and psychosocial well-being and how these are influenced by socio-economic status. (30) Because oral disorders are disproportionately concentrated in disadvantaged population groups, it has been shown that this group's quality of life is also more compromised. (30), (31)
Locker and co-workers (30) found a high level of older adults who were orally compromised, and this was significantly associated with diminished psychological well being and overall life satisfaction. Poor self rated oral health corresponded with decreases in morale and life satisfaction and increases in life stress even after controlling for other potential influences such as socio-economic status and general health. (10), (30) Tooth retention has also been associated with enhanced self esteem and greater quality of life outcomes. (17) While Locker and colleagues recognized that reverse causation is a potential in some study designs, meaning a better quality of life influenced improved tooth retention, they cautiously concluded that oral health appeared to be an important contributor to the overall well-being of elderly Canadians, particularly in the more financially disadvantaged groups. (30)
Assertions about the existence of oral health disparities are compelling but will need require further quantification if they are to be meaningfully addressed. Accurate assessment through measurement is the first step in mitigating oral health disparities in order to:
1. determine the underlying causal mechanisms of disparities,
2. target appropriate interventions, and
3. measure improvements subsequent to intervening.
Various measures of oral health status are available and questions surround which measures, or combinations, are best used.
Recognizing the broadening conceptualization of oral health, oral health status measures need to be reflective of this and become more comprehensive and include both traditional, more objective, measures along with contemporary, more subjective measures.
When comparing these measures, traditional measures tend to be more quantifiable and demonstrate high reliability and validity. They allow for statistical analysis and are well suited for targeted specific interventions. These are important measures that contribute to the concept of oral health. Some of these traditional measures, such as tooth loss, are linked to functional variables like chewing ability, whereas others are potentially life threatening as in oral malignancies. In addition, objective measures are associated in some socio-economic status, such as periodontal disease, with overall systemic health. Traditional oral health measures are often clinically based, making them more expensive and challenging to measure, and do not include how such manifestations impact the individual.
Contemporary measures tend to be more subjective relying on individual perceptions and tend to be more complex in their multidimensionality. While contemporary measures have been shown to correlate with traditional objective measures, subjective measures are important regardless of the association as we appreciate oral health to be a more all encompassing construct. They also have the advantage that they can be collected via non-clinical methods allowing for large samples to be surveyed typically at a fraction of the cost of clinical measures.
There is evidence that disadvantaged groups have poorer oral health status using both traditional and contemporary measures. It is concluded here that a combination of both objective and subjective measures will be required to accurately assess the oral health status of Canadians and determine the extent of oral health disparity occurring between disadvantaged sub-population groups and the majority of Canadians. Only then will a more organized agenda for addressing this oral health issue be developed on a comprehensive national level.
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Joanna Asadoorian, AAS(DH), BSc(DH), MSc
Associate Professor, University of Manitoba, School of Dental Hygiene Submitted 4 Sep. 2007; Last revised 7 Oct. 2008; Accepted 9 Oct. 2008. This a peer-reviewed article.
Correspondence to: Joanna Asadoorian; Joanna_Asadoorian@umanitoba.ca