The purpose of this article is to augment the existing research with recently released data from the 1996 Medical Expenditure Panel Survey, or MEPS; compare these data with similar data from the 1987 National Medical Expenditure Survey, or NMES; and identify changes that have occurred during those 10 years. Additionally, this article will examine the distribution of visits among provider types and the relationship between provider type and various socioeconomic and demographic characteristics.

	METHODS

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The MEPS—sponsored by the Agency for Healthcare Research and Quality, or AHRQ—is the successor to the NMES of 1987. The MEPS is the third in a series of nationally representative health surveys of the U.S. community-based population that is sponsored by the AHRQ (at that time, the Agency for Health Care Policy and Research) and the National Center for Health Statistics.^8–10 The MEPS collects health care expenditure, use and payment source data, along with socioeconomic, demographic and health insurance data, similarly to its predecessor surveys. It differs from similar earlier surveys in that data are collected for two consecutive years and the survey is fielded continuously. The target for the 1996 MEPS was a sample of 10,500 households participating in the National Health Interview Survey, or NHIS. To collect health expenditure and use data for 1996, an interviewer visited each MEPS household in person three times over an approximate 18-month period. The combined full-year 1996 response rate of the MEPS sample through the third round was 70 percent.¹⁰

MEPS provides national estimates (for which we provide descriptive and bivariate statistics) for the civilian noninstitutionalized U.S. population and includes dental visits, dental procedure and provider type categories for each of several socioeconomic and demographic categories. To ensure sufficient numbers to produce reliable national estimates, variable categories were combined when necessary. All estimates and statistics reported were computed taking into account the complex sampling design of MEPS with the use of the software package SUDAAN (Release 6.40, Research Triangle Institute, Research Triangle Park, N.C.).

	RESULTS

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There were 21,571 total participants in the 1996 MEPS, representing 268,130,477 noninstitutionalized U.S. civilians. Of these, approximately one-half (52 percent, n = 11,282) of the participants were female, 13 percent (n = 2,907) of the participants were African-American, and 58 percent (n = 12,427) of the participants were between the ages of 19 and 64 years.

The figures and tables provide national estimates for dental procedure and provider type by socioeconomic and other demographic variables. Figure 1 provides a distribution of procedures as a percentage of all dental procedures and demonstrates some interesting contrasts. For instance, while the combination of diagnostic and preventive services adds up to 65 percent of all dental procedures, the combination of periodontal and endodontic procedures represents only 3 percent collectively of all reported dental procedures. Figure 1 also provides similar data from the 1987 NMES for comparative purposes and shows that diagnostic services have increased (P < .05) substantially since 1987.⁴ Figure 2 provides a distribution of providers as a percentage of the population with at least one visit. Accordingly, 95 percent of all respondents who had a dental visit reported a visit to a general dentist. In contrast, about 2 percent of respondents who had a visit reported a visit to a periodontist or endodontist. Approximately 5 percent of similar respondents reported a visit to an oral surgeon and 7 percent reported a dental visit to an orthodontist.

View larger version (54K): [in this window] [in a new window]   Figure 1. Procedure type as a percentage of all dental procedures, 1987 and 1996. "All dental procedures" means at least one procedure type per visit; multiple procedures of the same type at the same visit are not included. Sources: Moeller and Levy4 and Cohen.10

View larger version (46K): [in this window] [in a new window]   Figure 2. Percentage of population who had had a dental visit, by provider type. Source: Cohen.10

Tables 3 and 4 provide national dental provider estimates for the U.S. civilian noninstitutionalized population. To ensure sufficient numbers to produce reliable estimates according to population characteristics, provider types and population characteristics were regrouped. For instance, provider types were categorized as "general dentist," "oral surgeon" and "other." "Other" included the provider types "endodontist," "periodontist" and "orthodontist." In addition, age, race and education were also regrouped. Table 3 provides the percentage distribution of people with a dental visit for each provider category. Overall, approximately 95 percent (N = 110,119,322) of the population that reported a visit to a dentist during 1996 described the visit as one to a general dentist. While approximately 5 percent (n = 5,656,024) of the population with a dental visit reported a visit to an oral surgeon, almost 11 percent (n = 12,581,767) collectively reported a visit to an endodontist, periodontist or orthodontist. While poorer respondents reported fewer visits (P < .05) to a general dentist and fewer (P < .05) visits to an endodontist, periodontist or orthodontist than did respondents with more income, they also reported similar rates of visitation to an oral surgeon. Also, while respondents with less education reported fewer (P < .05) visits to an endodontist, periodontist or orthodontist than did respondents with more education, they reported similar rates of visitation to a general dentist or oral surgeon.

Table 4 shows that Americans made approximately 288 million dental visits during 1996. Overall, approximately 81 percent (n = 232,959,903) of all reported visits were described as a visit to a general dentist. While slightly more than 3 percent (n = 9,502,691) of all reported visits were described as a visit to an oral surgeon, almost 16 percent (n = 45,497,731) of all reported visits were collectively described as a visit to an endodontist, periodontist or orthodontist. Poorer and less-educated respondents reported fewer (P < .05) specialty visits (endodontist, periodontist and orthodontist) and more (P < .05) visits to a general dentist than did similar respondents with more income or more education. On the other hand, younger respondents reported fewer visits to a general dentist and substantially more specialty visits (orthodontist).

	DISCUSSION

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While these data and analyses are useful, they do have limitations. Treatment and provider data are self-reported. Self-reporting of data may be less accurate than collection by observation or by dental record abstraction, potentially limiting the usefulness of these data. For instance, data are limited to those procedure or provider types that actually are reported by respondents and may not be fully exhaustive. Additionally, procedure data refer to only one reported procedure for each procedure type per visit. Multiple procedures of the same type reported during a single visit are recorded as a single procedure type. For example, a reported visit including a single filling would be reported similarly to a reported visit with three fillings. On the other hand, multiple procedures of different types during a single visit are reported separately. For example, a surgical procedure and a restorative procedure during a single visit would both be reported. In addition, service mix data are not differentiated according to time spent per procedure, cost per procedure or the impact of having insurance coverage. Finally, findings reported here indicate a somewhat lower utilization than has been estimated by other studies. For instance, the 1989 NHIS estimated that 57.2 percent of people visited a dentist that year, and the Third National Health and Nutrition Examination Survey, or NHANES III (which was conducted from 1988 to 1994), estimated that 52.4 percent or 66.9 percent of people visited a dentist during a particular year, depending on the definition of a year.^11–13 On the other hand, while these differences are notable and significant, the associations between sex, race/ethnicity, socioeconomic status and dental visits were consistent across these same surveys.¹¹

Poorer and less-educated respondents reported fewer specialty visits and more visits to a general dentist than did similar respondents with more income or more education.

While data limitations do exist, MEPS data provide current nationally representative estimates; include data elements that describe specific dental visits, procedures and type of provider; and offer details that are useful, important and not found elsewhere. For instance, MEPS data describe the magnitude and nature of dental visits in aggregate and for each of several demographic and socioeconomic categories. They also establish a baseline for rates of utilization, number and type of procedures, and provider type variation for the U.S. population. Additionally, while MEPS data may not provide an estimate for multiple services of the same type received during a single visit, they do provide an accurate estimate of the number of times that respondents visited a dentist to receive a particular procedure type.

These data expand on those of prior studies. For instance, results presented in this article depict the magnitude of dental procedures delivered and delineate the distribution of procedures and providers. Since 1987, the total number of dental procedures reported increased from 355 million procedures to about 422 million procedures in 1996.⁵ Remarkably, preventive and diagnostic procedures make up a substantial plurality of all dental procedures provided. In contrast, endodontic and periodontal procedures make up a surprisingly low percentage of all reported dental procedures.

When the MEPS data are compared to similar 1987 data, several trends can be observed. For instance, the relative number of diagnostic procedures, as a percentage of all procedures, has been increasing. While the relative rate of preventive services has remained stable, diagnostic procedures have increased from 26 percent of all procedures in 1987 to about 35 percent in 1996.⁵ In contrast, restorative, prosthetic, surgical and endodontic procedures have all declined as a proportion of total procedures over the past 10 years. Fewer reparative needs, increased interest and willingness to obtain diagnostic services and an improved economy may account for some of these changes.

Black, Hispanic and poorer respondents reported relatively fewer diagnostic and preventive visits and more oral surgical visits than whites or respondents with more income. Data appear to suggest that poorer and minority Americans may be receiving more late-stage care as a consequence of not receiving earlier primary care. This is troubling, since minority and poorer Americans usually receive less care overall than do their nonminority and wealthier counterparts. On the other hand, this relative differential between diagnostic and preventive visits and oral surgery has improved since 1987 for all Americans, including minority and poorer Americans.⁵ For instance, while the percentage of oral surgery visits among black Americans decreased from 14 percent in 1987 to 8 percent in 1996, the percentage of diagnostic and preventive visits increased from about 50 percent in 1987 to about 60 percent in 1996.⁵

	CONCLUSION

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MEPS data show the magnitude and nature of dental visits in aggregate and for each of several demographic and socioeconomic categories. These data help to establish baseline rates for utilization, number and type of procedures and provider type variation for the U.S. population. These nationally representative estimates include data elements that describe specific dental visits. For each respondent and for each dental visit, we are provided with details about dental procedures received and the type of practitioner providing the care.

The MEPS data appear to suggest that our profession has been successful in furthering preventive care use. Preventive procedures make up a substantial plurality of all dental procedures provided. In addition, when compared with similar 1987 data, the relative number of these procedures as a percentage of all procedures has been increasing. In contrast, restorative, prosthetic, surgical and endodontic procedures all have declined as a proportion of total procedures in comparison with their proportions in 1987. Changing needs, interest and willingness to obtain these services in addition to an improved economy may have accounted for some of these changes.

With these trends in mind, practitioners can better position themselves to provide the types of services their patients seek the most, and to shape their practices in light of what these trends project for the future.

View larger version (94K): [in this window] [in a new window]   Dr. Manski is a senior scholar, Agency for Healthcare Research and Quality, Rockville, Md. He also is a professor, Department of Oral Health Care Delivery, Dental School, University of Maryland, Baltimore. Address reprint requests to Dr. Manski at Department of Oral Health Care Delivery, Dental School, University of Maryland, 666 W. Baltimore St., Baltimore, Md. 21201, e-mail "Manski{at}Dental.umaryland.edu".

View larger version (90K): [in this window] [in a new window]   Dr. Moeller is a health economist, Center for Cost and Financing Studies, Agency for Healthcare Research and Quality, Rockville, Md.