Although an extensive body of theoretical and empirical literature on oral health has been published, a comprehensive dynamic model explaining social disparities in oral health has yet to emerge [25
]. A thorough review of all models goes beyond the scope of this paper. Therefore we discuss basic models of the use of dental health services. These models concentrate on dental services
rather than oral health disparities
Currently, our knowledge of dental care use is fragmented. The most commonly applied behavioral and social interaction models include Anderson's predisposing, enabling, need model of health services use [42
]; Rosenstock's (1966) health belief model; Mechanic's (1978) factors of sociocultural/psychosocial model [43
]; Antonovsky and Kats' (1970) preventive dental behavioral model [44
]; Fishbein and Ajzen's (1975) model of belief, attitude, and intention [45
]; Manning and Phelps' (1979) model of the demand for dental care [46
]; and the social exchange model by Grembowski et al. [25
Reviews of these models reveal several common themes [25
First, most behavioral models assert that an individual's use of health services is a function of the perceived threat of disease, past use of medical services, and perceived value of action. In particular, the individual has to be psychologically ready to become aware of a symptom as a problem and must then choose to visit a health-care professional as the appropriate action. A variant of the main theme of the behavioral models is Manning and Phelps' demand model of dental care, which casts the demand of dental care in economic terms of "demand" and "supply." Within the context of household, dental care is a weighted outcome determined by income, price of treatment, time cost, variables affecting tastes and preferences for preventive care, agreement among members of the joint household with respect to altering market opportunities, and the amount of income forgone due to seeking treatment, in conjunction with the expected expenses of dental treatment.
Second, the individual must perceive the preventive measure/medical service as feasible and efficacious such that it would reduce the perceived severity of the dental condition and would outweigh the gains from the associated psychological, physiological, monetary, time, and/or other types of costs [40
]. Alternatively, Antonovsky's salutogenic model emphasizes individual sense of coherence (comprehensibility) as the primary mobilizing resource through which patients utilize their ability to deal with stressful events (manageability), and to possess the motivation, desire, and commitment to cope (meaningfulness) [53
Third, the probability of a dental-care episode depends on the social interactional exchange nature of the patient-dentist relationship. As a variant of the behavioral model, the social interaction model emphasizes the power dynamics among individual characteristics of the patient, the provider, and structural characteristics of the health-care provider. During an episode of dental care, the dentist occupies an authority position – the "gatekeeper," who controls the flow of information exchange (e.g., concern for the patient's general health) and the extent to which the patient is informed of her/his dental needs and treatment options [25
Conversely, a patient may demand information regarding treatment options and remedies from a dentist and threaten to withdraw visits to that dentist. Similarly, dental health insurance providers, including government, may withdraw options for various dental treatments, based on the imbalance of economic costs and potential rewards for the insurance provider or because of perceived short-term savings to government. A very good example of this phenomenon was reduction of adult Medicaid dental benefits in Maryland, resulting in higher utilization of the hospital emergency room [55
]. Hence, a dental visit, according to the social interactionist perspective, involves a reciprocal, dynamic flow of power among the dentist, patient, and health insurance provider, based on costs, rewards, and level of compliance of the patient with the dentist and the health insurance provider.
These basic psychosocial and social interactional models are useful in examining how individuals make decisions in regard to visiting a dentist, and they have made important contributions in clarifying the utilization of health services. However, these traditional health belief models have notable limitations. First, they are biased in their emphasis on "rationality" – that is, patients are assumed to act as rational agents capable of conceiving a symptom as a threat, and medical professionals are assumed to have the ability to reduce this threat. Empirical studies have revealed only weak relationships between psychological concepts such as motivations, beliefs, attitudes, and opinions with preventive dental health behaviors, particularly among vulnerable populations such as minority patients and children in poverty [56
Moreover, the health behavior models employ a very narrow focus on individual psychological states and ignore the pivotal role of macro level influences – political economy, wealth distribution, and the unequal distribution and dissemination of new technology – along with the possible interaction of macro and micro level factors. Oral health is clearly situated within the larger framework of political, economic, and cultural forces. Empirical quests to discover the connection among biological processes, social structure, and oral health disparities have generally focused on measurable individual attributes (e.g., socioeconomic background, past experience with dentists, and the perceived ability of the patient to recognize his or her own ill health conditions) and have ignored the larger social and cultural contexts in which individual characteristics are defined.
For example, in epidemiological studies, socioeconomic status, or social class, is almost universally transmuted methodologically into attributes of individuals (e.g., income, occupational status, educational attainment). Socioeconomic status is a multifaceted and historical phenomenon defined and reproduced via social processes and power relations structuring materialistic conditions and life changes over time. Few empirical oral health models have made visible the contextual qualities in which structural/political forces constrain and perpetuate processes of social differentiation in society, which subsequently contribute to oral health disparities.
Fourth, these models fail to incorporate social capital factors, such as a "lay-referral" system, in which individuals share experiences and seek advice on their symptoms from family, friends, or relatives. In vulnerable populations, which often lack direct access to health-care professionals, social networks may have a strong influence that helps individuals seek needed health care [58
]. For example, a substantial proportion of ethnic minorities live in enclave communities in which a distinct "collective lifestyle" shapes local customs, values, norms, perceptions, and habitual practices (e.g., culturally specific food and personal hygiene practices), and few ethnic dentists are available to provide adequate dental care. As cultural perceptions are intimately tied to perceptions of the dynamic power relations between dentist and patient, ethnic minorities may come to rely mainly on their inherited social referral system to avoid contacts with dentists lacking the cultural competency to understand and appreciate their distinct habitual and dietary practices. Similarly, ethnic minorities with language barriers may rely primarily on their inherited community social networks when seeking dental care to avoid cultural and language barriers.
Fifth, the social interaction models have responded to critiques of the health belief model by placing more emphasis on the reciprocal and interactional nature of the dentist-patient relationship. Empirical support for this model, however, is sparse. Few empirical attempts have incorporated both the health belief and social interactional models in researching oral health disparities, particularly in studying the underlying dimension of social distance in relation to the cause of under-use among vulnerable minority populations.
Finally, most of the published models concentrate on dental care as the major determinant of oral health and oral health disparities. Hay and colleagues, in an application of the Grossman model described above, reported analyses showing that number of dental visits had a negative effect on the number of decayed teeth, demonstrating a beneficial effect of dental care [61
]. Number of visits was related positively to oral hygiene but was not significant statistically. These results must be regarded as tentative, however, because of the study's small sample size. Newhouse and Friedlander found no association between the prevalence of periodontal disease and an area's dental resources, measured by the dentist-population ratio, in 39 areas of the U.S. [62
]. Weinstein and colleagues found no relationship between time spent with dental hygienists and levels of oral plaque and inflammation [63
]. Moreover, education efforts toward patients were inversely related to the level of the problems presented. That is, healthier patients received more attention, and patients with more problems received less attention [64
Dental care, particularly preventive dental care, is an extremely important determinant of oral health inequality. Less is known about the broader social and cultural determinants that influence oral health practices, the values and beliefs about teeth, mouth, and face, and how these values, beliefs, and practices vary across different social and cultural groups. Dental care and dental insurance are not the major determinants of oral health disparities [65
]. Concentrating only on providing access to dental care may detract from the more powerful effects of social stratification, power differentials, and the understanding of different cultures and their beliefs and practices that contribute to oral health. Broadening the scope of the conceptual framework is intended to open the door to new and different channels for intervening, while recognizing that professional care is necessary throughout life to maintain good oral health and to benefit from evidence-based technological advances.