Methods. This study is based on the analyses of data regarding dental visits and private dental insurance among the population 2 years of age or older from the 1989 and 1999 National Health Interview Surveys.

Results. Overall, the percentage of the population with a dental visit rose from 57.2 percent in 1989 to 64.1 percent in 1999, while the percentage with private dental insurance fell from 40.5 percent to 35.2 percent.

Conclusions. Although a higher percentage of people with private dental insurance reported having a dental visit than did those without private dental insurance in both years, the increase from 1989 to 1999 in the percentage of those with a visit was larger among the uninsured.

Practice Implications. If this trend persists, a smaller portion of practicing dentist’s clientele will be insured. This may affect demand for services, as well as front office operations.

In 1980, 56 percent of all full-time employees of medium and large private establishments participated in an employer-provided dental care plan. Participation reached 77 percent in 1984, but fell to 57 percent in 1995.² A recent survey of full- and part-time workers in private industry found that 32 percent received dental care benefits through their employers in 1999.³

Although less than one-half of the population has private dental insurance, these patients account for 64 percent of patients in the average dental office.⁴ Children with private dental insurance are more likely to have had a dental visit during the previous year than children without such insurance. This is true for children with all levels of family income.⁵ Thus, recent decreases in the percentage of employees with private dental insurance could have a negative impact on the percentage of the population with a dental visit.

This article examines recent National Health Interview Survey, or NHIS, findings regarding private dental insurance and dental visits, including how the levels of private dental insurance and dental visits vary by major demographic variables. We also include an analysis of changes in the levels of private dental insurance and visits from 1989 to 1999.

	METHODS

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
The NHIS is a multipurpose survey conducted by the National Center for Health Statistics, Centers for Disease Control and Prevention, and is the principle source of information on the health of the civilian, noninstitutionalized, household population of the United States. NHIS data are collected through a personal household interview. Most information about oral health in the NHIS is obtained for all people 2 years of age or older. Data are released on an annual basis.

People with private dental insurance visited a dentist more often in the past 12 months than did those without private dental insurance in both 1989 and 1999.

The interviewed sample for the 1989 NHIS was composed of 45,711 households containing 116,929 people. The total household response rate was 94.9 percent.⁶

The interviewed sample for the 1999 NHIS consisted of 37,573 households, which yielded 97,059 people in 38,171 families.^7,8 Some information was collected for everyone in each family. Additional information, such as the dental visit and private dental insurance questions, was collected from two subsamples. The adult subsample consisted of one adult per household for a total of 30,801 people 18 years of age or older. The child sub-sample consisted of one child per household, for a total of 12,910 children zero to 17 years old. The total household response rate in 1999 was 87.6 percent. The final response rate for the adult sample component was 69.6 percent. The final response rate for the child sample component was 78.2 percent.

The analysis focuses on respondents who reported having had a dental visit within the past 12 months, had a private health insurance plan that covered dental services or both. We assumed that respondents with an unknown interval since their last dental visit had not had a dental visit in the previous 12 months. We assumed that respondents with unknown private dental insurance coverage had had no private dental insurance coverage at the time of the survey. In our analysis of patient visit data, we controlled for the effect of private dental insurance, and we highlighted findings that demonstrate the influence of private dental insurance on the level of dental visits. We focus on private dental insurance in this article because it was the only dental insurance information available in the NHIS. Therefore, public programs—including Medicaid and the State Children’s Health Insurance Program, or SCHIP—that usually are targeted to children in low-income families, were not included.

We used a SUDAAN statistical package (Version 8.0, Research Triangle Institute, Research Triangle Park, N.C.) to calculate standard errors and perform statistical tests since it includes adjustments for the correlation introduced by the complex sample design used for the 1989 and 1999 NHIS.

	RESULTS

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Figure 1 shows that people with private dental insurance visited a dentist more often in the past 12 months than did those without private dental insurance in both 1989 and 1999. The difference between people with private dental insurance and those without fell from 23.8 percent in 1989 (71.4 percent versus 47.6 percent, respectively) to 17.1 percent in 1999 (75.2 percent versus 58.1 percent, respectively). Although not shown in Table 1, in 1989, the 23.8 percentage point visit difference was consistent across all demographic groups reported in Table 1. By 1999, the visit difference between insured and uninsured populations had decreased in all but two groups: Hispanics and those below the federal poverty level, or FPL.

View larger version (38K): [in this window] [in a new window]   Figure 1. Percentage of population 2 years of age or older with a dental visit within the past year, 1989 versus 1999 National Health Interview Survey, or NHIS.

Figure 2 shows that while the percentage of the total U.S. population with a dental visit increased from 57.2 percent in 1989 to 64.1 percent in 1999, the percentage with private dental insurance fell from 40.5 percent of the population to 35.2 percent.

View larger version (35K): [in this window] [in a new window]   Figure 2. Percentage of population with a visit and percentage of population with private dental insurance, 1989 versus 1999 National Health Interview Survey, or NHIS.

In 1989, 62.8 percent of Hispanics with private dental insurance reported having had a dental visit versus 39.5 percent of Hispanics without insurance. The difference in 1999 was 69.0 percent versus 46.3 percent. The 23.3 percent visit difference between the insured and the uninsured in 1989 was almost the same in 1999: 22.7 percent (data not shown).

The percentage of the population with private dental insurance dropped from 1989 to 1999 for whites and Hispanics but held steady among blacks (Table 2).

Poverty level. Although people at or above the FPL reported having a higher level of visits in both years than did those below the FPL, both groups reported an increase in visits from 1989 to 1999. Those below the FPL reported the only increase in private dental insurance, but the increase was from a relatively low level in 1989.

Among those below the FPL, the visit difference between those with private dental insurance and those without was 21.9 percent (60.8 percent–38.9 percent) in 1989 and 23.4 percent (68.5 percent–45.1 percent) in 1999 (not shown in Table 1 and Table 2).

Results are in line with findings from other studies regarding recent declines in the percentage of private sector employees with private dental insurance.

Figure 3 (page xxx) shows the percentage of the population with a visit by dental insurance status by income defined as the percentage of the FPL for 1999. There was a strong income gradient for the percentage with a dental visit among those without private dental insurance—45.1 percent for those in the lowest income group to 76.6 percent in the highest income group. This income gradient was much less pronounced among those with insurance (68.5 percent to 80.2 percent). Dental insurance’s impact among those in the highest income group (those at 400 percent of FPL or higher) was modest—80.2 percent for those with insurance versus 76.6 percent for those without.

View larger version (32K): [in this window] [in a new window]   Figure 3. Percentage of population with a dental visit by private dental insurance by poverty level, 1999 National Health Interview Survey, or NHIS.

Industry category. Among those 18 years of age or older, the level of private dental insurance varied by industry category in 1989 and 1999 (Figure 4, page xxx). Figure 5 (page xxx) shows the percentage of total employment by industry sector. In both years, more than two-thirds of employees worked in three sectors: service, wholesale and retail trade, and manufacturing. The level of private dental insurance in the manufacturing sector was relatively high, but manufacturing fell as a percentage of total employment from 19.1 percent in 1989 to 15.8 percent in 1999. Compared with the manufacturing sector, the percentage of those with private dental insurance was relatively low in the service sector, and the service sector as a percentage of total employment rose from 32.2 percent in 1989 to 38.1 percent in 1999.

View larger version (33K): [in this window] [in a new window]   Figure 4. Percentage with private dental insurance by industry category, 1989 versus 1999 National Health Interview Survey, or NHIS (18 years of age or older).

View larger version (31K): [in this window] [in a new window]   Figure 5. Percentage of total employment by industry sector, 1989 versus 1999 National Health Interview Survey, or NHIS (18 years of age or older).

	DISCUSSION

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
Results from the NHIS we report in this article are in line with findings from other studies regarding recent declines in the percentage of private sector employees with private dental insurance. According to the NHIS, the level of dental insurance varies by industry category. These differences, along with different rates of growth in the sizes of the largest industry categories from 1989 to 1999, may have contributed to the overall decline in private dental insurance.

The increase in the percentage of people with a dental visit from 1989 to 1999 and the corresponding decrease in the percentage with private dental insurance occurred within the context of an overall increase in the U.S. population. In absolute terms, the result of these trends was 34.1 million more dental patients in 1999 than in 1989, despite an absolute decrease of 2.6 million people in the U.S. population with private dental insurance.

The decline in the percentage of the population with private dental insurance from 1989 to 1999 is surprising because it occurred during a period of strong economic growth. The growth in the U.S. economy may help explain how the percentage of the population with a dental visit rose despite the decline in the percentage with private dental insurance. For example, real (2000 dollars) median family income grew from $47,512 in 1989 to $50,595 in 1999.⁹

The elderly (people 65 years of age or older) reported a 10.3 percentage point increase in dental visits from 1989 to 1999 despite the fact that a relatively low percentage had private dental insurance. The increase in dental visits among the elderly is related partly to the drop in the percentage of the elderly who are edentulous. For example, the percentage of edentulous people in the 65 to 74 years of age group dropped from 45.6 percent in the period of 1971 to 1974 to 28.6 percent in the period of 1988 to 1994.¹⁰ As more people keep their natural teeth when they get older, they are more likely to continue a pattern of regular dental visits.

The increase in the percentage of the elderly population with a visit also may be related to recent increases in their net worth. For example, the median real (1998 dollars) net worth of families with the head of the family being 65 to 74 years old grew from $112,300 (1992) to $146,500 (1998).¹¹ It is not known, however, how much of the increase in net worth resulted in an increase in discretionary income.

The visit difference between blacks and whites fell from 14.8 percent in 1989 to 9.8 percent in 1999, and the insurance difference fell from 9.4 percent to 4.0 percent. These changes may be related to relative changes in the income distribution for both groups. The percentage of blacks below the FPL fell from 31.9 percent in 1990 to 23.6 percent in 1999.¹² The decrease among whites was much smaller—10.7 percent to 9.8 percent.

Among all racial and ethnic groups examined, the NHIS data show that Hispanics had the lowest levels of dental visits and private dental insurance in 1999. Further analysis of the dental visit and insurance data for Hispanics is needed. This effort should be considered in the following context: between 1990 and 2000 the growth rate among Hispanics (57.9 percent) was considerably higher than for blacks (21.5 percent) and whites (8.6 percent). According to the U.S. Census Bureau, Hispanics now outnumber blacks in the United States.¹³

The only increase from 1989 to 1999 in the percentage of the population with private dental insurance was among those below the FPL. This finding was not expected. According to the NHIS, however, there was an increase in the working poor (that is, the percentage of those below the FPL who were employed) from 36.8 percent in 1989 to 41.0 percent in 1999.^7,8 At least some of those employed in 1999, but not in 1989, probably obtained private dental insurance as an employment benefit.

Although the 1999 NHIS data showed an income gradient for dental visits among those without private dental insurance, this gradient was reduced for those with insurance. This finding suggests that there can be a role for private insurance in reducing disparities in access to dental care related to income.

Among children, private dental insurance was shown to have a greater impact on the likelihood of a dental visit than was Medicaid dental coverage.⁵ Findings from a second study suggest that SCHIP dental programs, which were designed to resemble private insurance models and to reimburse dentists at rates close to market rates, hold the potential to address problems associated with dental access for low-income children.¹⁴

Two important trends may have had an impact on the levels of private dental insurance and dental visits in the United States since 1999. First, economic growth began to slow in the spring of 2000, resulting in an increase in the U.S. unemployment rate.¹⁵ If increases in real family income as a result of strong economic growth in the 1990s partly explain the increase in the level of dental visits despite a decrease in the level of private dental insurance, then the level of dental visits may fall during times of economic downturn.

Second, after moderate increases during the 1990s, health care insurance premiums have been rising at increasing rates. Employers are responding by shifting a greater proportion of health care costs to their workers.¹⁶ As a result, more and more Americans may have to choose between various types of health care coverage.

	CONCLUSION

TOP ABSTRACT METHODS RESULTS DISCUSSION CONCLUSION REFERENCES

 
We found an increase from 1989 to 1999 in the level of dental visits in all of the demographic subgroups we examined. We found a corresponding decrease in the level of private dental insurance in all subgroups, except the elderly, which had no change, and those below the FPL for which there was an increase.

People with private dental insurance were more likely to report a dental visit than were those without private dental insurance in both years. We found the relationship between private dental insurance and a dental visit in 1999 to be strongest among those with lower incomes. However, only 14.1 percent of those below the FPL reported having private dental insurance.

Disparities between blacks and whites in terms of dental visits and private dental insurance were smaller in 1999 than in 1989. Gaps between Hispanics and non-Hispanics, however, have not been reduced. Among all of the racial and ethnic groups we examined, Hispanics reported having the lowest levels of dental visits and private dental insurance in 1999.

Because the level of dental visits is related to the level of private dental insurance, and because both appear to be sensitive to overall economic changes, trends in all three areas should be monitored closely.

View larger version (131K): [in this window] [in a new window]   Mr. Wall is the manager, Statistical Research, Health Policy Resources Center, American Dental Association, 211 E. Chicago Ave., Chicago, Ill. 60611, e-mail "wallt{at}ada.org". Address reprint requests to Mr. Wall.

View larger version (123K): [in this window] [in a new window]   Dr. Brown is associate executive director, Health Policy Resources Center, American Dental Association, Chicago.