Do people in different regions use dental services differently?

"That there are considerable geographic variations in health service utilization is beyond doubt. Many studies have shown that regional differences in the utilization of medical services are a common phenomenon. As Loft and Lewinter (1998) have pointed out, they are found in countries with very different health care systems and for a wide range of medical and surgical procedures.

"A few studies to illustrate this point will suffice. Fowkes and McPake (1986) examined outpatient activities in the National Health Services in England and Wales from 1974 to 1982. They found that in half of the specialties, a threefold or greater difference in outpatient attendance per population occurred between the highest and lowest regions.

"Regional variation is not restricted to medical service use. The same is true with respect to dental service utilization. Data from the Canada Health Survey show that 50.1 percent of Canadians visited a dentist at least once in 1978/79. Highest utilization rates were observed in Ontario (56 percent) and British Columbia (55 percent), while only 30 percent of the respondents in Newfoundland reported using dental services (Mangas and Charette 1986)....

"Research on geographic variations is of interest not only to researchers, but also to health care planners. Researchers are increasingly interested in identifying the determinants of regional differences in service utilization. Health care planners, on the other hand, are interested in their policy implications. Substantial differences could imply inequity in health service provision, inadequacy of access, or problems in resource allocation. As Anderson and Pulcins (1992) have noted, although such studies cannot be used to specify the appropriate levels of care, wide variations in utilization rates in relatively homogeneous populations suggest that some individuals do not receive the potential benefits of required services while others are overserved and exposed to the financial waste and risks associated with the delivery of inappropriate services. Regional variation studies are also important in light of the decentralization of health services in a number of Canadian provinces. Part of the regionalization process involves the allocation of resources to regional health authorities. If the allocation formula is based on existing patterns of service use and if there are substantial and unjustifiable regional differences in utilization, it could perpetuate an inequitable distribution of resources. Thus, it is important to understand why service utilization in one region is so much higher or lower than in another.

"The purpose of the present study is to examine regional variations in medical and dental services. More specifically, we compare the differences in regional variations in the utilization of medical and dental services in Ontario and seek to understand why there is more variation in one type of health service than in the other. Since few studies have been done to examine the differences in regional variations in the utilization of different types of health service, we hope to shed new light on this phenomenon.

"When northern and southern Ontario are compared with respect to the rates of utilization of the services of physicians (general practitioners/family physicians and specialists), the differences are relatively small. Basing our estimates (for respondents 12 years of age and older) on the Ontario Health Survey (OHS) data, 81 percent of northerners, compared with 83 percent of southerners, have at least one contact with a physician over a one-year period. Differences in the utilization of the services of dentists, on the other hand, are quite substantial, with only 57 percent of northerners having at least one contact with a dentist over a one-year period compared with 66 percent of southerners. These macro-level figures tend to mask considerable subregional variations. In the first part of this paper, we explore these variations in greater detail by comparing the utilization rates of smaller geographical areas as defined by Public Health Units (PHUs)....

"In the second part of the paper, we examine why there are less regional variations in the utilization of medical services than in the utilization of dental services. At least three hypotheses can be advanced on the basis of empirical findings from other studies.

"First, such differences could arise as a function of differential access. One of the most important aspects of differential access is geographical maldistribution of practitioners, which could affect utilization in different areas.

"Second, while there is universal coverage for most medical services in Canada, this is not the case for dental services even though an increasing proportion of the population has third-party coverage. Differences in regional variations in utilization could reflect ways of funding health care.

"Third, differences of geographic variations could reflect health beliefs and how people view the two types of service. For instance, it is possible that while medical care is regarded by most as essential, dental care is largely seen as discretionary.

"The principle data source for this paper is the Ontario Health Survey (described in greater detail in Ministry of Health 1992a, 1992b, 1992c). Conducted in 1990, the OHS is a population-based health survey designed to be representative of each of the province's 42 PHUs....

"An analysis of the OHS data on health service utilization shows that while PHUs do not differ substantially with respect to contacts with physicians, there are considerable regional differences in contacts with dentists. The main objective of the study is to account for the difference in regional variations in the utilization of these two major types of health service.

"Differences in regional variations in the utilization of medical and dental services are primarily a function of contacts made with dentists, not physicians. Higher differentials, in effect lower rates of using dental services, are not strongly influenced by the number of practitioners available or the proportion of the population with dental insurance coverage. Instead, the differentials are significantly associated with specific oro-dental behaviour, general health conditions, and economic status.

"There is some evidence to indicate that while the number of dentists in an area and insurance coverage affect dental service utilization, the effects of human resources supply and insurance do not appear to be consistently linear. Once a certain level is reached, their effects taper off. The study by Brodeur et al. (1990), mentioned in an earlier section, shows that the addition of more dentists in Quebec after 1985 did not spur further growth in utilization. Similarly, studies by Lewis and Thompson (1992) and Zammit (1993), among others, show that the removal of financial barriers for dental services resulted in an increase in the uptake of dental treatment. But the increases tended to be modest and a substantial proportion of the eligible population did not take advantage of the free dental care provided. In the case of Ontario, the province may have reached that level or threshold. Our analysis has shown that although there are considerable regional variations in dentist-to-population ratio and the proportion of the population covered by dental insurance, most of the factors affecting regional variations in contact with dentists are general health conditions and certain dental health behaviors. The policy implication is that while making dental services more accessible is still needed, particularly in certain rural and northern regions of the province, the real challenge in encouraging better oral health and preventive dentistry is through health promotion and education. The results of this analysis suggest that it is the changing of health behaviors in general and dental health practices in particular and the improvement of overall health conditions that will make a difference in equalizing dental service utilization across the province.

"According to Philips (1979), social geographers have made fairly broad descriptions of aggregate behavior, but detailed explanation of emerging patterns has seldom been achieved. This lack of explanatory power of aggregate-scale analysis has prompted the move toward investigation at the level of the individual, in which the individual person or individual household becomes the main unit of analysis. We believe this view is overly pessimistic. As this study has demonstrated, although some of the factors affecting regional variations in dental service utilization are individual-level variables, such as dental health behaviors and satisfaction with health, they tend not to be randomly distributed. For instance, there is a strong north-south contrast in relation to whether people see a dentist only when the dental problems are experienced. From a policy perspective, unless there is unlimited resources for health promotion and education, it may be necessary to target those regions where a substantial proportion of the population exhibit negative health attitudes and behaviours. The study of regional variations helps identify those regions where remedial actions should be targeted."

From: J.R. Pitblado and R.W. Pong (1995). Comparisons of Regional Variations in the Utilization of Medical and Dental Services in Ontario: A Test of Several Hypotheses in D.J. McCready and W.R. Swan, eds., Change and Resistance: Proceedings of the 6th Canadian Conference on Health Economics. Kingston, Ontario: Canadian Health Economics Research Association.