Sociodemographic and Workload Characteristics of Dentists Who Participated in National Survey, 1995

The available work for recent graduates who are establishing practices will be affected by the workload and retirements of dentists working in the same geographic area; however, comprehensive, standardized data on the sociodemographic characteristics and workload of dentists in different provinces and territories in Canada are not available. In 1995, we conducted a national survey of dentists in Canada to investigate access to care for patients with bloodborne pathogens and compliance with recommended infection control practices.^6,7 This paper reports the results of a comparison of sociodemographic and workload characteristics of dentists in different provinces and territories.

Methods

There were 15,232 dentists listed by dental regulatory authorities in Canada in 1995. Dentists who did not actively treat patients were considered ineligible. A stratified random sample of 6,537 dentists was selected to participate in the survey. The strata consisted of the 10 provinces and 2 territories. Lists of licensed dentists were obtained from each provincial or territorial authority. All listed dentists from the smaller provinces/territories (Newfoundland, n = 149; Prince Edward Island (PEI), n = 48; Nova Scotia, n = 418; New Brunswick, n = 246; Saskatchewan, n = 332; Yukon Territory, n = 13; and the Northwest Territories (NWT), n = 34) were included. Dentists from the remaining provinces were randomly sampled such that the size of the subsamples would yield reasonably small confidence intervals for the estimates of interest.^8-10 The final sample size, adjusted for non-delivery of questionnaires, was 6,444.

The survey instrument, tests for reliability, administration of the survey, weighting of the data and investigation of nonresponse bias have been described elsewhere.^6,7,11 To ensure anonymity of response, the study was designed such that no individual could link names and responses. Each observation in the sample was weighted to allow for different probability of selection and nonresponse among the provinces and territories. The expansion weight was calculated for each subject by taking the score for each item, multiplying by the number of dentists in that province or territory, then dividing by the number of respondents in that province/territory who answered that item.¹² While the expansion weight is reasonable for the estimator of the population total, it is inappropriate for the calculation of variance used in test statistics and confidence intervals. Hence, the relative weight was calculated as the expansion weight divided by the mean of the expansion weights over all subjects who responded to that item.¹² All statistical computations were done using the relative weight as the sampling weight. Pearson’s test of association was used to compare categories using SPSS/PC+ (SPSS Inc., Chicago, IL).

Results

The response rate adjusted for non-delivery was 66.4%; a total of 174 respondents were ineligible, leaving 4,107 responses for data analysis. Eighty-nine per cent of survey participants were general dentists. We found significant provincial and territorial differences in sociodemographic characteristics (Table 1) including gender (female: range 10% to 30%), years since graduation (³ 30 years: 4% to 15%), marital status (married: 40% to 88%), patient load (³ 20 patients per day: 10% to 52%); number of hours per week seeing patients (25 to 40 hours: 39% to 81%; > 40 hours: 9% to 56%), population of the town or city where the primary practice is located (> 500,000: 0% to 67%) and age. The proportion of dentists who were aged ³ 50 at the time of the survey ranged from 5% (NWT) to 26% (Ontario); the number of dentists who were aged ³ 60 years ranged from 0% (NWT and Yukon Territory) to 10% (Newfoundland). The number of dentists aged 55 to 59 years ranged from 0% (NWT) to 10% (Yukon Territory).

Discussion

Significant differences between provinces/territories were noted for age, gender and marital status. Higher proportions of dentists younger than 30 years were reported from the NWT, Yukon Territory and Quebec. Conversely, fewer than 10% of dentists practising in British Columbia, Ontario, Nova Scotia and PEI were less than 30 years of age. At the other end of the spectrum, more than a quarter of respondents in British Columbia, Ontario and Newfoundland were more than 50 years of age. In addition, British Columbia, Ontario, Saskatchewan and Newfoundland had a greater proportion of respondents ³ 60 years of age compared with the other provinces and territories. These results indicate that there may be more opportunities in these provinces for younger dentists as a result of retirements. Data for 1998 provided by licensing authorities in British Columbia and Manitoba show that the proportion of dentists more than 50 years of age is continuing to grow in these provinces.

The results of this study indicate that, in 1995, the highest proportion of female dentists were working in the Yukon Territory (40%), Quebec (30%), the NWT (22%) and Nova Scotia (20%), and the lowest proportion were working in PEI. Recent data provided by licensing authorities indicate that there has been little change in the proportion of male to female dentists in Manitoba. However, the proportion of female dentists in the Yukon has dropped. The higher percentages of younger and unmarried dentists practising in the Yukon and the NWT may be influenced by the economic incentives to work in these areas.

There were significant variations in workload across the provinces. Respondents from PEI, New Brunswick, Nova Scotia, Newfoundland and British Columbia reported seeing the most patients per day. In contrast, nearly one-third of dentists in the Yukon reported seeing fewer than 10 patients per day compared with dentists in other provinces or territories. With the exception of the NWT, approximately three-quarters of respondents reported that they saw patients for 25 to 40 hours per week; more than half of respondents from the NWT reported practising more than 40 hours per week.

This study provides cross-sectional data from 1995 that can be used as an indication of sociodemographic and workload differences between dentists in different provinces and territories. In addition, the age data can be used to indicate future requirements for human resources to provide dental services in different parts of Canada. Recall bias was probably minor, as recall related to average number of hours worked per week and number of patients seen in a typical day was limited to the last three months. Previous investigation revealed minimal evidence of nonresponse bias.¹¹ It is clear, however that further investigations of geographic variations in human resources and workload of dentists are required. In addition, we need updated projections for demand for the dental services and treatment that will be required for the aging population across Canada and elsewhere in the new millennium.^13,14

Acknowledgment: This study was supported by a grant from the National Health Research and Development Program, Health Canada (6606-5463-AIDS).

1. Douglass CW, Gammon MD. The future need for dental treatment in Canada. J Can Dent Assoc 1985; 51:583-90.

2. Beagrie GS. Dental manpower. An FDI/WHO viewpoint. J Can Dent Assoc 1986; 52:52-5.

3. Lewis DW. Dental manpower supply and demand projections and changing demography and dental disease. J Can Dent Assoc 1986; 52:33-40.

4. House RK. Estimating future dental care requirements. The implications for dental manpower. J Can Dent Assoc 1987; 53:99-105.

5. Stangel I. Factors affecting the future need for dental manpower in Canada and Quebec. J Can Dent Assoc 1992; 58:1005, 1008-10, 1014.

6. McCarthy GM, Koval JJ, MacDonald JK. Factors associated with refusal to treat HIV-infected patients. The results of a national survey of dentists in Canada. Am J Pub Health 1999; 89:541-5.

7. McCarthy GM, Koval JJ, MacDonald JK. Compliance with recommended infection control procedures among Canadian dentists: the results of a national survey. Am J Infect Control 1999; 27:377-84.

8. Warwick DP, Lininger CA. The sample survey: Theory and Practice. New York: McGraw-Hill; 1975.

9. Statistics Canada. The health of Canadians: Report of the Canadian Health Survey. Ottawa: Minister of Supply and Services Canada; 1981.

10. Catlin G. Survey Methods. In: Rootman I, Warren R, Stephens T, Peters L, editors. Canada’s Health Promotion Survey Technical Report. Ottawa: Minister of Supply and Services Canada; 1988. p. 11-15.

11. McCarthy GM, MacDonald JK. Non-response bias in a national study of dentists’ infection control practices and attitudes related to HIV. Comm Dent Oral Epidemiol 1997; 25:319-23.

12. Lee ES, Forthofer RN, Lorimor RJ. Analyzing Complex Survey Data, Sage University Paper Series on Quantitative Applications in the Social Sciences, 07-001. Beverly Hills: Sage Publications; 1989.

13. McNally M, Kenny N. Ethics in an aging society: Challenges for oral health care. J Can Dent Assoc 1999; 65:623-6.