People covered by health insurance that pays all of their dentists' bills have fewer cavities and missing teeth, as well as less gum disease, than people with no dental coverage or plans that make only partial payment.
But if that finding, in a new Rand Corp. study, doesn't seem particularly surprising--and perhaps even absurdly obvious--its authors say that, in a way, is precisely the point.
The conclusion is important, they say, because with businesses and government focusing increasingly on efforts to control health-insurance costs and hold down benefit payments, it is important to know what insurance practices most directly affect people's everyday health.
These mundane areas of health insurance have not exactly been accorded stepchild status, say the Rand researchers, but they are sometimes perceived as potentially expendable because they treat people who aren't really sick and involve conditions that are often minor--even though they may easily become major problems.
Health-insurance plans in general, in the view of many public-health experts, have been slow to recognize preventive care of all kinds as financially and actuarially worthwhile, and many plans do not yet even cover routine checkups.
The Rand study found that children, particularly 12- to 17-year-olds, but 6- to 11-year-olds as well, who are covered by dental insurance, benefit from such insurance most. One of the researchers said the team also found that youngsters from 6 to 17 in insured families tend to be far more aware of oral hygiene practices and how certain foods--such as excessive amounts of candy--can harm their teeth.
Effect on Younger People
And, overall, people 35 and under show the most measurable effects of dental insurance in general. People from 36 to 65 did not show major differences in oral health depending on the type of insurance they have--perhaps, the Rand team speculated, because gum disease is more advanced in the age group and tooth decay is, naturally, less of a problem.
The report, which is being published in this month's Journal of the American Dental Assn., was part of research financed by the U.S. Department of Health and Human Services.
The dental research inquiry is a companion study to an analysis of the effects of health insurance featuring total payment of bills compared to other plans in which patients must pick up some or much of the tab themselves. The health-insurance study--also government-financed--was published in 1983 and its conclusions were consistent with those of the dental study.
The survey of the effects of dental insurance represents one of the first thorough analyses of oral health-care benefits ever conducted, even though dental insurance has grown enormously in popularity in the last 10 years. Dr. Howard Bailit, head of the Department of Health Administration at the Columbia University School of Public Health, who led the Rand team, noted that while only 15 million Americans had dental insurance a decade ago, the number now stands at nearly 100 million with private insurance and 20 million covered under the Medicaid plan (Medi-Cal in California).
To determine whether dental benefits actually have an appreciable effect on routine oral health, Bailit and a team that included Joseph Newhouse, who also headed the earlier study of health-insurance benefits and their effect, examined the dental health of more than 4,800 people in six cities and counties in Ohio, Massachusetts and South Carolina. The subjects were divided among people with dental insurance that pays 100% of bills, plans that cover 95%, 50% or 25% of costs and those with no insurance at all.
Among the key findings were these:
--All age groups in the total coverage group had better dental health records. But the 12-to-17 age group was most likely to show benefits.
--The benefits were greatest among children and teen-agers with total coverage from families with the lowest educational levels. Such children had fewer decayed and missing teeth and more fillings--implying better long-term dental health and retention of treated teeth--than those who had less insurance.
--Teen-agers and people who had serious gum disease when the survey began had "significantly better" periodontal health if they received total coverage than if they had no insurance or were forced to pay part of the costs themselves.
--Overall, people under 35 when the study ended--the research continued for five years, concluding in 1982--were in better shape in terms of oral health if they had total insurance than if they had partial or no coverage.
"Our results suggest that reducing cost sharing for dental services will improve oral health for those younger than 35," the Rand team concluded, "and especially for subgroups of the population with the poorest oral health.
"This implies that significant gains in oral health could be expected if coverage were extended to the millions of children, teen-agers and young adults who are without dental insurance."
Both Newhouse and Bailit agreed that the study's findings, which represent important statistical confirmation of a concept public-health advocates have long assumed to be valid, may sharpen the focus of an ongoing national debate over health-care costs.
The dental insurance survey establishes, they said in separate telephone interviews, that there is a discernible effect on overall health if many routine, preventive types of care are encouraged by top-quality insurance benefits.
The Rand conclusions also seemed to contradict a developing trend in health insurance in which employers are seeking to shift more of the costs of care to workers in the form of larger co-payments, higher deductibles and greater restrictions on coverage.
"I think the real issue is that as they (government and private insurers) try to cut back on benefits to try to contain health-care costs, the question is which services are they going to cut back on," Bailit said. "The question of what services actually provide health is really the critical issue.
"If you spend more for some services, you may produce more (direct improvements in) health than in others. It would appear that there clearly will be some gains if you address more in dental insurance. And, by the same token, there will be some increases in ill health if you cut those benefits."
Newhouse noted that the new dental insurance study had reached conclusions comparable to the 1983 survey of health-insurance benefits. He noted that the routine treatment of high blood pressure and dental health care are strikingly analogous in that each involves ongoing care whose direct costs are low compared to the more exotic and high-tech treatments, like cardiac surgery, but which are crucial not only to making people feel better on a day-to-day basis but in avoiding high-cost alternatives in the future if the routine conditions are ignored.
Greatest Health Gains
Newhouse contended that one of the most significant conclusions of the dental study was the finding that low-income children and teen-agers from families with low educational levels reflect the greatest health gains from substantial insurance coverage--whether it is government-funded or privately paid.
In the 1983 study, a Rand team reviewed the health status of nearly 4,000 people who had total health insurance or a variety of plans featuring coverage with different deductible levels. Notable among the findings was that free care was far more likely to lead to better treatment of poor vision and improved control of high blood pressure.
Improved high blood pressure control among the free-care group was linked, the researcher said, to reduction in the risk of early death among subjects with hypertension.
Both studies are part of the Rand Health Insurance Experiment, an ongoing project that is seeking to unravel the complexities of the actual and perceived effects of health insurance.