Is There a Sound Basis for Deciding How Many Dentists Should Be Trained to Meet the Dental Needs of the Canadian Population? Systematic Review of Literature (1968-1999)

• Gerardo Maupomé, CD, M.Sc., DDPH RCS(E), PhD •

• H. Jack Hann, DDS, MPH, FRCD(C) •

• Jeannine M. Ray, BA, M.Sc. •

Abstract

A systematic review was conducted of the literature on human resources planning (HRP) in dentistry in Canada, critically assessing the scientific strength of 1968-1999 publications. Inclusion and exclusion criteria were applied to 176 peer-reviewed publications and “grey literature” reports. Thirty papers were subsequently assessed for strength of design and relevance of evidence to objectively address HRP. Twelve papers were position statements or experts’ reports not amenable for inclusion in the system. Of the remaining 18 papers, 4 were classified as projections from manpower-to-population ratios, 4 as dental practitioner opinion surveys, 8 as estimates of requisite demand to absorb current capacity and 2 as need-based, demand-weighted studies. Within the 30.5 years reviewed, 53.4% of papers were published between 1982 and 1987. Overall, many papers called for a reduction in human resources, a message that dominated HRP during the 1980s, or noted an increase in the demand for services. HRP publications often had questionable strength or analytic frameworks. The paradigm of busyness-scarcity evolved from a belief around an economic model for the profession into a fundamental tenet of HRP. A formal analysis to establish its existence beyond arbitrary dentist:population ratios has usually been lacking.

One problem is the lack of an evaluation framework to assess the body of knowledge addressing human resources planning (HRP) in dentistry. The most obvious solution is to undertake a systematic review whereby the literature is appraised through a strict design to make the review process more comprehensive, to minimize the chance of bias and to strengthen its reliability.¹

This study is a systematic review of the literature on HRP in Canada between 1968 and 1999.

Materials and Methods

This review was undertaken using primarily standard methods.¹

The first step was to select databases for conducting the review. Initially, Medline, Embase, Current Contents and Biological Abstracts were the electronic databases selected. Once it had been established that they overlapped substantially, only Medline was used. MeSH terms employed were dentistry, dental health services, dentists, dental staff, public health dentistry, dental care, dental auxiliaries, dental hygienists and dental assistants. Each of the terms was focused to trends, manpower, and supply and distribution. All searches were then combined with the term Canada and “exploded” to include all 10 provinces. A keyword search was also undertaken for dentistry or dental or dentists plus the term manpower, subsequently combined with the term Canada. Results were limited to the years 1968 to 1999.

Second, the references cited in relevant articles were searched by hand.

Third, since a great deal of “grey” literature was known to exist, a catalogue search (non-serial publications) of the University of British Columbia library system was undertaken. This university biomedical collection is the second largest in Canada. The keyword searches were dentistry or dental or dentists or hygienists plus manpower and Canada and 1968 to 1999. Before starting the search for publications, a data extraction sheet was designed by 2 calibrated public health dentists from examples used in other systematic reviews. The sheet was used in pilot trials and improved several times to test operational definitions. An article was included in the review if it was (i) original research, symposia proceedings, a position statement or an experts’ report addressing the planning of human resources (HR) in dentistry and allied dental pro fessions in Canada, (ii) written in English or French, (iii) published from January 1968 to July 1999 or (iv) part of the “grey” literature, i.e., not listed in mainstream databases but published by a professional, governmental or scientific body. A publication was excluded if it was (i) a case report, editorial, letter, news or comment, unless it addressed in a meaningful way the evidence discussed in other included publications, or (ii) a description of HR without a clear planning emphasis. After reviewing these features, a decision was made to include or exclude a paper.

An inventory of included papers was developed according to the type of document, the use of research methods (if applicable), the HRP factors involved, a summary of the study design and the conclusions and recommendations implicitly or explicitly outlined. Papers were classified according to their HRP approaches following the DeFriese and Barker³ system (see Table 1). This system offers a critical appraisal of the relative sophistication of the methodologies used in HRP studies. It implicitly assumes that health needs and health care needs are met by dental personnel, therefore relegating to a secondary position the impact of population-based interventions or individual preventive strategies. The system does not take into account changes in technology or shifts in the emphasis placed on underemployed preventive technologies. Perhaps most importantly, the DeFriese and Barker system implies that dental education is a product that is purchased almost independently of it being a means to improve health or meeting demands for care of the population.

Data were analyzed as required using descriptive statistics and Spearman’s rho test.

Results

Of the 176 papers that resulted from the searches, 146 were reviewed and eliminated. Only 30 papers were included in the review (see Tables 2 to 6 ).^4-33 Eleven were position statements and one was an experts’ report not amenable to direct inclusion in the DeFriese and Barker system (Table 2). A further 9 experts’ reports, one symposium proceedings and 8 original research papers were included in the system.³ Of these 18 papers, 4 were projections from manpower-to-population ratios (Table 3), 4 were dental practitioner opinion surveys (Table 4), and 8 were estimates of requisite demand to absorb current capacity (Table 5). While no econometric practice-productivity studies were found, 2 need-based, demand-weighted studies (Table 6) were published in the 30.5-year interval. Half of the papers (53.4%) were published during 1982 to 1987.

To establish whether studies published more recently had more sophisticated designs, Spearman’s rho analysis was done on the year of publication and the categories of the system³ (excluding the 12 unclassified papers). We assumed that the higher the category, the more sophisticated the design of the study. The rho coefficient was +0.472 (p = 0.048), suggesting that more recent papers described more sophisticated approaches in addressing HRP issues.

One of the most important items in this body of literature is the overall position conveyed on the need to increase or decrease the HR supply. Thirteen papers (43.3%) concluded that an HR oversupply might already exist or was about to occur at the time of publication.^{9-13,15,17,18,20,24,28,29,32} Many of these reports called for a specific reduction in HR for all of the schools. The need to protect the academic and research capabilities of schools was emphasized by certain authors, indicating that it would be preferable to reduce the number of schools than to implement a dramatic reduction for entering students in each faculty.³² An increase in the demand for dental services (insurance-generated) was also contemplated as a solution to the oversupply problem. Eight papers (26.7%) indicated or implied that the HR were appropriate to their evaluation framework or should be increased.^{7,8,19,21,23,25,27,33} A further 9 papers (30%) either did not offer an unequivocal statement about whether HR should increase or decrease or offered both recommendations depending on different types of personnel or situations.^{4-6,14,16,22,26,30,31} The small number of studies precluded the use of a statistical test, but by charting the year of publication together with the recommendation to increase or reduce HR, we concluded that papers lacking an unequivocal statement were evenly distributed along the 30.5 years reviewed. Calls for increases were more common in the 1970s and virtually ceased after 1985. Recommendations to reduce HR started to appear in the late 1970s and became the dominant theme during the 1980s.

Discussion

It is not feasible to include every paper in a review of the literature. The present approach offers a novel strategy to understanding HRP literature relevant to Canada. It cannot, however, be considered an exhaustive processing of the information, as some publications may have been omitted by virtue of the terms under which they were listed in the databases. In other cases a subtle challenge was posed, in that certain papers had a borderline status between the included and excluded categories. Furthermore, the heterogeneity of reviewed studies made it infeasible to synthesize the findings in a single measure (using meta-analytic techniques).

What are the methods used so far to estimate the number and profile of dental personnel that should be trained? Tables 2 to 6 describe the various HRP factors and methods that were contemplated in the papers reviewed. The factors are fairly comprehensive and should allow a broad overview of the evolving HRP situation at the national or provincial level. The main problem with the methods used so far is the questionable strength of the majority of strategies selected: 73.3% of the documents are position statements, experts’ reports or symposia proceedings. The largest individual category of papers did not resort to a systematic approach to HRP (Table 2) as classified by DeFriese and Barker.³ In the case of research papers, the scientific standards were heterogeneous. While some designs were solid in their planning and undertaking,^11,14,21 other papers were thinly disguised personal manifestos in which evidence, methods and conclusions or recommendations were poorly related or lacked scientific rigor.¹² A further group of papers failed to include information essential to understanding what was actually done or assumed in the planning process,^15-17 and it was therefore difficult to fully evaluate their contributions. A great many assumptions and even hearsay underlie this literature, suggesting that the main thrust of some documents was their political or policy motivations. There is nothing intrinsically wrong with this feature: HRP is not an apolitical enterprise.³ What is problematic is the generalized assumption that in the absence of sound evidence, a perceived HR oversupply can be considered a sufficient basis for closing dental schools or reducing enrolment, a conclusion stated in 43.3% of papers. Similarly, an increase in HR should be driven by the epidemiological profile and the features of the demand for services in the population.³¹ An argument to reduce dental personnel should not be based on fears of lack of busyness or a deviation from an arbitrary dentist:population ratio. Resources available to support a health care system are finite; choices have to be made to meet basic needs within a clearly defined social contract.³⁴

Where does this trend to reduce the HR supply come from? As a result of recommendations made in the 1960s by the Royal Commission on Health Services, a policy was introduced to expand dental HR. At that time, the clinical practice model, the technological state of the art and the prevalence of oral morbidity and tooth mortality in the population offered a large marketplace to dental practice. In this affluent environment, no real necessity was perceived for planning the type of services needed or the health status goals that would define success in professional endeavours. Many concepts had blurred boundaries between access and demand, between health status and health care and between perceived individual need and social responsibility. The dominant thinking was that an HR undersupply would ensure a favourable marketplace in the future. We call such thinking the paradigm of busyness-scarcity, i.e., a belief that as long as the number of dentists is slightly less than what the market would bear, business will be good for the profession. Such an economic model was accepted as part of a knowledge structure and an explanation of reality.³⁵ The professional discourse endorsing the paradigm became stronger during the 1970s and was taken for granted in the 1980s, even though contradictions were becoming apparent. As early as 1972, Lewis²² drew attention to the danger of simplistic interpretations derived from the paradigm. An evaluation of the basis for such a paradigm indicates that no formal analysis supported most papers. In many instances, the reactive character of these documents emphasizes that no objective criteria were used to define a given resources:demand relationship. DeFriese and Barker³ summarized this shortcoming as follows: “Planners and health professionals have a tendency to see manpower as an end in itself, rather than a means to the attainment of more general health goals. All too often, health manpower … rather than the health-care services that people seek … is given primary emphasis in the planning process.” The conceptual simplicity of the paradigm and the inherent risk implied for dentists’ income encouraged the professional associations³² and the planners^15,17,18,30 to believe that the number of HR was the main “problem” that needed attention. Such hegemonic ideology supported by repetition³⁶ strengthened the paradigm, and in so doing defined policies and political statements.

By acknowledging that one of the challenges to HRP is to preserve the social relevance of, and social responsibility within, dental education, while evolving synchronously with the needs of the population,³⁷ it is feasible to recognize the necessity of documenting the burden of illness as a prerequisite in the allocation of resources in HRP.³ Such documentation makes easier the task of distinguishing the advantages and disadvantages of the different HRP methods. Overall, only 2 studies^14,33 employed a clearly outlined research rationale coupled with an approach whereby the actual needs and demands of the population were considered in HRP. As in other publications, these 2 papers assumed that, in the absence of Canadian data accurately portraying preventive and rehabilitative needs, American data could be used instead. There are no Canada-wide epidemiological studies on oral health status. While this solution to assessing needs is simple, it undermines the relevance of the analyses to the Canadian scenario. Perhaps more importantly, it also highlights the paradox of Canadian society spending $4.7 billion in dental care annually (1993 direct expenditures)³⁸ without accurately establishing how those funds should be targeted or how successfully the actual patterns of disease are being addressed. To place this expenditure in context, similar figures for cancer and pregnancy costs were $3.2 and $2.0 billion, respectively. Such lack of information precludes the undertaking of need-based, demand-weighted studies that constitute the gold standard in HRP today. While Canadian epidemiological trends suggest that decay experience and tooth loss are declining, it is still unclear how oral care needs are changing across diverse groups. There are substantial treatment needs in the younger groups in North America,³⁹ and new cohorts of Canadians are reaching old age with considerable treatment needs in more teeth.⁴⁰

The foundations that we propose to support a more rational HRP process are, first, to accept the necessity of conducting periodic national surveys to objectively determine oral health needs and demands.⁹ Second, by negotiating the application of ethical guidelines, it should be possible to agree on directives to allocate resources effectively, to compensate providers fairly and to offer a reasonable range of services⁴¹ to maintain a functional level of oral health for the population at large. Finally, an indirect result of the first 2 phases would be to define acceptable minimum standards for oral health status and oral health care for the Canadian population through consensus by professional, academic, governmental and lay stakeholders. Such standards should be pertinent to the needs of the various age groups, culturally acceptable and subject to cost-benefit analyses to determine their viability compared to alternative options. Such options must objectively appraise the benefits and costs of implementing alternative models of health care delivery.

Acknowledgments: We gratefully acknowledge the financial support of the S. Wah Leung Endowment Fund, Vancouver, British Columbia. We also acknowledge the expert observations and feedback of an anonymous reviewer to an earlier version of the manuscript.

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