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Agency for Healthcare Research Quality

Dental Care

Improving Access and Quality

Research in Action, Issue 13

Dental care research funded by the Agency for Healthcare Research and Quality (AHRQ) looks at the impact of a wide variety of factors. These include the impact of reimbursement, race, income, and age on access to and use of dental care.

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Background / Access to Adequate Care / Measuring the Quality of Dental Care / Ongoing Research and Programs / Conclusion / AHRQ-Funded Research / References

By Mark W. Stanton, M.A.


The oral health of Americans has improved in recent years, yet considerable gaps in the provision of dental care remain, according to a recent report by the Surgeon General.1

This Research in Action highlights dental care research sponsored by the Agency for Healthcare Research and Quality (AHRQ). Studies look at the impact of factors such as reimbursement, race, income, and age on access to and use of care.

Research suggests that educating families about how to enroll in and access the Medicaid system, streamlining Medicaid administrative procedures, and adjusting provider reimbursement could facilitate broader access to dental care. Studies show that specific treatments such as dental sealants for children may have a positive impact on both health outcomes and costs. The quality of dental care can be further improved by developing and using performance measures for specific treatments. Finally, the production of evidence reports evaluating research on various aspects of care helps to advance evidence-based dental practice and thereby improve the quality of care.

The Surgeon General's recent report states that oral health is essential to the general health and well-being of all Americans.1 Although oral health extends beyond dental health, the report clearly stresses the importance of the two leading types of dental disease:

  • Tooth decay (dental caries).
  • Periodontal disease.

Dental care can be either preventive or restorative. Preventive care, such as tooth cleaning and dental sealants, is aimed at avoiding dental problems. Restorative care repairs problems such as those caused by tooth decay and periodontal disease.

Making a Difference

Poor children receive fewer preventive health care visits than those with higher incomes.

Dental sealants can reduce the number of cavities and decrease the cost of care in the Medicaid program.

Minority elderly receive less dental care because of financial barriers to care.

Unexplained variations in dentists' clinical decisions are widespread.

Relative cost-effectiveness of dental crowns and their alternatives has not been established.

Use of performance measures by dental plans could improve quality of care.

Evidence-based practice is advanced by evidence reports evaluating various interventions.

Oral Health Improves Overall but Gaps Exist

Over the past several decades, oral health in the United States has improved.a Among most age groups, the average number of teeth per person affected by dental caries has decreased. Also, the average number of teeth per person that show no signs of infection, as well as the proportion of the population that is caries free, has increased. In addition, a lower proportion of U.S. adults have lost all their natural teeth (a process associated with both tooth decay and periodontal disease) now than was the case two decades ago. This improvement is most pronounced at older ages.

Despite the overall improvement in oral health status, gaps in the provision of care remain. Over the 20-year period 1977-96, the gap in the use of services between low-income people (those with incomes under 200 percent of the Federal poverty level) and higher income people (those with incomes over 400 percent of the Federal poverty level) increased.2 The number of preventive visits is below recommended levels, and access to dental care remains problematic for minorities, the elderly, children on Medicaid, and other low-income children. For example:

  • More than one third (36.8 percent) of poor children ages 2 to 9 have one or more untreated decayed primary teeth, compared to 17.3 percent of nonpoor children.
  • Uninsured children are half as likely as insured children to receive dental care.3
  • Untreated dental decay afflicts one-fourth of children entering kindergarten in the United States.
  • Low-income and minority children have more dental cavities than other children.
  • Poor Mexican-American children ages 2 to 9 have the highest proportion of untreated decayed teeth (70.5 percent), followed by poor non-Hispanic black children (67.4 percent).
  • Poor Mexican-American and non-Hispanic black children see the dentist less often than other children.
  • Less than one of every five poor children enrolled in Medicaid receives preventive dental services in a given year, even though Medicaid provides dental coverage for enrolled children.

In addition to the considerable access problems faced by poor and Medicaid-eligible children, poor elderly people and minorities have their own problems with access.

  • In the 50-69 age group, non-Hispanic blacks (31.2 percent) are more likely than Mexican Americans (28.2 percent) or non-Hispanic whites (16.9 percent) to have at least one tooth site with periodontal disease.
  • In the age category 70 years and over, the percentages rise to 47.1 percent, 32.0 percent, and 24.1 percent for the three groups.

With more elderly people having discretionary income and retaining their natural teeth, demand for dental services among the elderly has grown. But this demand can be substantially influenced by financial barriers and other health concerns. Studies show that the elderly typically underuse needed dental services.

The underuse of cost-effective preventive services such as dental sealants, plastic coating applied to protect the chewing surface of teeth, also illustrates that dental care in the United States has room for improvement.

a. Unless otherwise referenced, the information in this section comes from the Surgeon General's report.

Performance Measurement Is in its Early Stages

Beyond the issues of access and underuse, there is the question of how to measure the quality of care that is delivered. The ability to measure the quality of dental care is a key to improving it, but most plans do not collect data to produce standardized measures. Once the process of performance measurement is underway, it will be possible to identify specific treatment areas where improvements can be made. For example, some research has shown that the treatment of dental patients with previous restorations (different repairs to teeth, such as fillings, crowns, and bridges, that restore original function) has a relatively high degree of variability, which may or may not be related to patient-specific factors. Further research may be able to show which type of restoration is most effective. Measuring performance becomes more feasible when evidence reports are available that systematically evaluate the efficacy of techniques for the diagnosis, prevention, and treatment of dental caries and other dental diseases.

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Access to Adequate Care

AHRQ-funded studies have identified disparities in the dental care used by poor children and elderly blacks. These studies have shown that, despite Federal requirements, children who are enrolled in the Medicaid program or are among the near-poor receive less dental care than is recommended for their age group. For example, they are less likely to receive regular preventive visits than those in higher income groups. Also, they are less likely to have their teeth treated with dental sealants (plastic coating on the chewing surfaces of teeth), a treatment shown to improve outcomes and lower overall treatment costs. Poor elderly minority people also may not receive needed dental care. The reasons for these disparities are varied, but they include financial barriers to care, unavailability of dentists in poor neighborhoods, administrative complexities in qualifying for Medicaid eligibility and treatment approval, and insufficient participation by dentists in the Medicaid program.

Low-Income Children Have Unmet Dental Needs

An AHRQ-supported study analyzing data from the 1996 Medical Expenditure Panel Survey (MEPS)b on use of preventive dental care by 6,595 children and adolescents found that poor children have significantly fewer preventive dental visits than those with higher incomes.4 Poor and near-poor children age 18 and under were only about half as likely to have had preventive dental visits as children in middle or high income brackets across racial/ethnic groups (Figure 1).c For example, 16 percent of poor black children and 12 percent of near-poor black children had preventive visits, compared with 26 percent of those with middle or high income.

The same study also analyzed Maryland-specific data from the Centers for Medicare & Medicaid Services and found that only 31 percent of Medicaid-insured children had received preventive care during 1996. This proportion was unexpectedly low, given that States are required by Federal law to provide dental care to all Medicaid-eligible children from birth to 21 years of age. The required coverage includes annual dental exams, prophylaxis and fluoride treatments, and other emergency, preventive, and restorative services, such as fillings and oral surgery.4

The situation for Medicaid children in Georgia and Alabama is comparable to the situation in Maryland, according to a study by the Children's Health Insurance Research Initiative (CHIRI™),d funded by AHRQ, The David and Lucile Packard Foundation, and the Health Resources and Services Administration.5 Less than a third of Georgia Medicaid children (30 percent) received dental care in 1997, and less than a quarter of Alabama Medicaid children (18 percent) received dental care in 1999. Almost all of the children who had any dental care received preventive care, with approximately half receiving acute dental services such as emergency or restorative care.

Another AHRQ-funded study reported that half of 1,297 Medicaid-enrolled schoolchildren in North Carolina never used dental services. Among children who got care, 45 percent needed restorations in primary teeth and 25 percent needed restorations in permanent teeth. Among these children, 29 percent had all their dental needs met, 28 percent had their needs partially met, and 43 percent had no dental needs met.6

b. MEPS is the third in a series of medical expenditure surveys conducted by AHRQ. It is a nationally representative survey that collects detailed information on the health status, access to care, health care use and expenses, and health insurance coverage of the civilian noninstitutionalized population of the United States.
c. In 1996, the Federal poverty line was approximately $16,500 for a family of four. The near-poor are those between 101 and 200 percent of the Federal poverty line.
d. The CHIRI™ study is based on claims data from Alabama (1999) and Georgia (1997); therefore, its findings cannot be directly compared to the earlier study based on 1996-97 survey data from MEPS.

Dental Sealants for Medicaid Children Are Underused

Even when poor and near-poor children have access to a dentist, they may not receive generally accepted recommended care such as dental sealants. Dental sealants prevent tooth decay, save money, and are an important preventive measure, complementing the use of fluorides. They work by preventing decay from developing in the pits and fissures of teeth, channels that are often inaccessible to brushing and where fluoride may be less effective. All States now include sealants as a dental benefit for children enrolled in their Medicaid dental programs; however, dental sealants are underused.

An AHRQ-funded study that examined the dental experiences of 15,438 children enrolled in the North Carolina Medicaid program from 1985 to 1992 found that sealants were effective in preventing tooth decay in the chewing (occlusal) surfaces of the bicuspid and molar teeth.7 This reduced the need for CRSOs (caries-related services involving the occlusal surfaces of these teeth). The most effective use of sealants was among children who had more dental services for cavities before sealant placement. Furthermore, researchers found that restoration rates (cavity fillings) for high-risk children peaked at 8 years for unsealed teeth and at 9 years for sealed teeth (18 vs. 8 percent). The effects of sealants are greatest when the child is roughly 8 years old; after that age, sealant effectiveness declines.

The Medicaid program saved money by using sealants for children prone to cavities. The greatest difference between expenses for sealed and unsealed teeth ($15.21 per molar) occurred among the high-risk patients at age 9. These savings were realized within a 2-year period following sealant application among children with two or more prior CRSOs.

However, AHRQ research has documented that, in spite of the savings realized from their use, these treatments are underused in the Medicaid program.6 For example, among 219 North Carolina children enrolled in Medicaid who needed sealants for 615 teeth, only 21 teeth (3 percent) were sealed, 195 (32 percent) received fillings, 23 (4 percent) were extracted, and 376 (61 percent) received no treatment within a 2-year followup period.

Poor Elderly African Americans May Lack Access

The Surgeon General's report found that people 55 to 74 years of age have higher rates of periodontal disease and also have an increasing amount of tooth decay compared to younger adults. The elderly's use of dental care can be substantially influenced by financial barriers and other nondental health concerns.

AHRQ-supported researchers analyzed dental and medical claims data from 1983 to 1992 for 3,458 individuals age 62 years and over who visited two urban health care facilities and participated in a special Medicare-waiver program that reimbursed for dental services (not usually covered by Medicare).8 They compared age, race, medical use, and pharmaceutical use among people who used both medical and dental services (dental users) and those who used only medical services (nondental medical users).

Researchers found that among poor, elderly city residents, blacks were twice as likely as whites to use dental services that are reimbursed by a Medicare waiver program. Eliminating financial barriers among less affluent and less educated minority elderly people has a definite effect on their use of oral health care services.

In addition, nondental medical users had twice as many medical visits each month and more than twice the monthly medical charges in the program as dental users had (.99 visit vs. .56 visit per month and $43 vs. $21 in charges per month). Dental users were more likely to be younger (born after 1910) and black (63 percent vs. 36 percent white) than nondental users, with twice as many blacks as whites participating in the dental waiver program.

The decrease in oral health care services associated with increased use of medical services seems to indicate that as health declines, people are less inclined or able to seek dental care. This could indicate a decrease in the priority given to oral health care, decreased ability to access oral health care services, or both. The researchers suggested that African Americans in the study were more likely to use dental services because their access to services improved. The absence of private-sector dentists in their own communities was mitigated by the availability of a city-run facility providing dental services under a special Medicare-waiver program that reimbursed for dental services.8

Access to Medicaid Dental Care May Be Improved

AHRQ-supported researchers have offered their own suggestions about how to improve access to Medicaid dental care. Their suggestions focused on two areas:

  • Education.
  • Administrative simplification.

For example, the research team that studied the impact of income on the use of preventive care suggested that poor and near-poor families may not know how to use available resources effectively. They concluded that educating families eligible for Medicaid and State Children's Health Insurance Program (SCHIP) programs about how to enroll and access the system may be essential for the success of these programs.4

Another group of researchers who studied schoolchildren and Medicaid suggested that streamlining Medicaid administrative procedures (e.g., Medicaid eligibility, treatment approval) could also contribute to better care. For example, instituting a mechanism for prior approval of care once a child appears for his or her first dental visit would help to ensure that all needed care could be completed quickly and without the need for further approvals.6

One factor contributing to insufficient dental care may be that dentist participation rates in Medicaid remain low. The CHIRI™ study5 found that children were more likely to receive restorative dental care if they lived in counties where there was a greater than average number of Medicaid-participating dentists per enrollee.

The dentist participation rates are themselves partly a function of the reimbursement levels provided under the Medicaid program. One AHRQ-funded study examined what happened to participation when reimbursement rates were increased.9 The study found that increasing provider reimbursement by 23 percent, even when accompanied by a doubling of enrollment for individuals under age 21, had only marginal effects on increasing access to dental services for the Medicaid population. From 1985 to 1991, Medicaid enrollment doubled in North Carolina; during the final 4 years of the study (1988-91) there was a 23-percent increase in Medicaid reimbursement to dentists. However, following the implementation of these two measures, the percentage of dentists seeing 5 or more Medicaid-insured children per quarter remained fairly constant and the percentage seeing 10 or more such children per quarter increased only slightly.

Among providers seeing at least 10 Medicaid children per quarter, an increase in real Medicaid reimbursement from $13 to $14 yielded an expected 3 percent (.83 person) increase in the number of Medicaid children seen per quarter. Pediatric dentists were significantly more likely to participate in Medicaid than general dentists (probability of .58 vs. .20). Pediatric dentists also saw more than 2.5 times as many Medicaid children per quarter as general dentists did. Dentists in solo versus group practices were more likely to participate in Medicaid, and dentists with more years of experience were less likely to participate.

The researchers who conducted the North Carolina study did not conclude that increased reimbursement had little or no effect on dentist participation. Instead, they concluded that greater participation may require much larger increases in reimbursement.9

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Measuring the Quality of Dental Care

An important focus of performance measurement to improve quality of care is the study of variations in the use of dental procedures. These variations (by geographic area, practice type, etc.) suggest the possibilities of overuse and underuse. Similar concerns are found in medical care. For example, health services research has examined variations in the provision of medical care for patients with similar medical conditions living in different geographic areas. It has also studied patterns of possible overuse and underuse of medical procedures.10-12 These studies in turn have raised questions about the extent to which patient-specific factors, provider preferences, and practice styles influence treatment decisions.

Unexplained Variations in Clinical Decisions Are Widespread

Are documented variations in the provision of dental treatments simply reflections of the art of dentistry or are they caused by uncertainty or disagreement about which treatment is the most effective? Because quality-of-care measures for evaluating the performance of oral health insurance plans have not been available, these questions have not yet been answered and the quality of care furnished cannot be systematically evaluated.

In a comprehensive review of the literature regarding variation in dentists' clinical treatment decisions, AHRQ-funded researchers found substantial variation in areas such as the rate of provision of specific procedures, the cost and number of procedures recommended for specific patients, diagnoses, intervention decisions, and treatment selection for individual teeth.13

For example, in one study that compared six capitated practices with five fee-for-service practices, average rates of restorative services were higher in the fee-for-service practices: three times as high for adults and four times as high for children. In another study, the proposed treatment costs for two patients examined by 15 North Carolina dentists ranged from $180 to $1,340 for one patient and $420 to $2,400 for the other.13

From their review of the literature, the researchers concluded that even when differences in patients are accounted for, variations in dentists' clinical decisions are widespread. Such variations, which raise questions about possible overuse and underuse of care, definitely need to be better understood.13 The studies discussed below have begun to lay the foundations of evidence-based performance measurement for dental care.

Cost-Effectiveness of Different Restorative Treatments Is Unknown

Further studies examine restorative treatment recommendations and the effects of the choice of treatment on the cost of care. One study examined the extent to which dentists agreed about the treatment of 1,187 teeth in 43 patients.14 Each patient was examined by an average of 6.6 dentists, with a total of 51 participating dentists. Overall, agreement among the participating dentists in recommending individual teeth for treatment was 62 percent. Among all teeth receiving at least one recommendation for treatment, only 22 percent received a unanimous recommendation. However, over half of all instances of lack of agreement occurred when one dentist's recommendation differed from those of all the other dentists examining the tooth. The results suggested that much of the variation stemmed from basic differences in recommended treatment for individual teeth with specific conditions. In cases where a tooth had been previously restored, differences in treatment recommendations tended to be greater. The researchers conclude that their study shows the need to develop objective criteria for treatment of teeth with previous restorations.14

Another study by the same researchers explored the effects of variation in both dentists' decisions to treat and choices of restorative treatment on the cost of care.15 The patients selected for the study needed decisions about a variety of single-tooth restorations and had no substantial periodontal complications. Three types of restorations—amalgam fillings, composite fillings, and crowns—varying widely in cost were considered.e Thirty-seven patients were examined individually by several practicing dentists. For each dentist's recommended treatment for each patient, the total cost of restorative treatment was calculated first by using the least expensive treatment possible for each tooth designated as needing treatment and second by using the treatment selected by the dentist. The average cost per patient of the treatment selected ($893) was three times larger than the cost per patient of basic treatment ($269). Most dentists did not consistently recommend either higher or lower cost treatment plans.

The findings suggest that inconsistencies in both dentists' decisions to perform restorations and their selection of treatment have a profound effect on costs. However, the researchers caution that since there is a relative lack of information about the cost-effectiveness of low- and high-cost treatment alternatives, appropriate treatment planning and rational cost containment are very difficult. The researchers suggest that comprehensive efforts to improve consistency across the profession would be more productive than focusing on "outlier" dentists who choose more high-cost treatments.15

e. Amalgam fillings are made from a silver/mercury mixture. Composite fillings contain a mixture of filler particles such as silica, aluminum, zinc, tin, copper, and iron in a liquid resin. A crown is full coverage for a tooth (used when the tooth cannot be restored by a filling). Crowns are much more expensive than either the amalgam or composite fillings. Most dental schools teach that a crown is the preferred treatment for substantially compromised posterior teeth with extensive caries, fractures, or large defective restorations (fillings), as opposed to a direct metal alloy (amalgam) or composite resin filling.

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