Early association of expanded Medicare dental benefits to dentist billing in Medicare

Abstract

Background.

Although Medicare is barred from covering most oral health care, policies enacted by the Centers for Medicare & Medicaid Services have expanded coverage of dental procedures for Medicare beneficiaries receiving certain medical treatments and made it easier for dentists to submit claims electronically.

Methods.

The authors extracted monthly counts of the number of Medicare-billing dentists from the Centers for Medicare & Medicaid Services “Doctors and Clinicians” files from January 2021 through December 2024. Considering the implementation dates of the reforms, we estimated a single-group interrupted time-series analysis separately for all dentists, oral surgeon dentists, and non–oral surgeon dentists to measure any association of the reforms with dental care provider participation in Medicare.

Results.

After the Medicare dental benefit expansions, the preexisting downward trend in the number of Medicare-billing oral surgeons continued, although the transition to electronic claim forms appeared to be associated with a reverse in this decline. Among non–oral surgeon dentists, after the first dental benefit expansion, the monthly increase in the number of billing dental care providers accelerated 0.8% (95% CI, 0.47% to 1.12%).

Conclusions.

Despite new opportunities for Medicare beneficiaries to access oral health care, there have not been marked increases in the number of dentists billing Medicare, a trend largely associated with oral surgeons. Dentists may remain hesitant to participate in Medicare or are unaware of the new policies.

Practical Implications.

The authors lacked access to claims volume or patient outcome data and these elements will be needed in future research to further assess the association of Medicare dental reforms on patients.

Oral health constitutes an essential aspect of overall health across the lifespan, including during older adulthood.^1,2 Medicare provides near-universal insurance health care coverage for Americans 65 years and older as well as people with certain disabilities. Enrollment in Medicare leads to improved health outcomes.³ However, since its implementation in 1965, Medicare has been prevented from covering oral health care services.

The statutory exclusion of oral health care services under traditional Medicare (TM) limits coverage to dental procedures deemed essential for the success of specific covered medical treatments.⁴ As a result, most older adults experience worse oral health outcomes and lower rates of oral health care use than working-age adults.⁵ In a 2023 study, researchers found that when older adults transitioned to Medicare, edentulism increased by 4.8% and use of restorative oral health care services decreased by 8.7%.⁶ Dental disease is more prevalent among low-income and racial and ethnic minority beneficiaries.² Although Medicare Advantage (MA), the privatized form of Medicare that now enrolls more than one-half of all Medicare beneficiaries,⁷ offers supplemental benefits including oral health care, only 8% of those plans offer a comprehensive range of oral health care benefits. The restrictive characteristics of most MA dental plans are associated with greater unmet oral health care need and barriers to care.^8,9

Since 2023, the Centers for Medicare & Medicaid Services (CMS) have announced Medicare policy changes that expand coverage for oral health care for beneficiaries with specific medical conditions. Unlike previously proposed universal Medicare dental benefits, this expansion does not require legislative approval because it is codification of existing policy.¹⁰ On January 1, 2023, Medicare beneficiaries undergoing evaluation for organ transplant, cardiac surgery, or cardiac valvuloplasty became eligible.¹¹ On January 1, 2024, this was expanded to beneficiaries with head and neck cancer, beneficiaries receiving high-dose antiresorptive therapy (eg, intravenous bisphosphonates) or chimeric antigen receptor T cell therapy for the treatment of cancer, and beneficiaries receiving oral health care screenings before chemotherapy.⁴ It is estimated that approximately 1.3 million people enrolled in TM have the aforementioned medical conditions and would be eligible for oral health care services in Medicare.¹² Given that approximately one-half of all Medicare enrollees choose an MA plan,⁷ we estimated there would be 2.6 million people eligible for oral health care services in TM or MA.

There will be a need for additional dentists to treat patients newly eligible for Medicare dental benefits. On July 1, 2024, Medicare officially began accepting electronic 837D dental claims, a major change from the paper claim forms that existed previously.¹³ The aim of this transition was to reduce administrative burdens for dentists participating in Medicare and to facilitate the claim submission process.

The policy changes mandated for TM apply by default to MA plans as well and required MA plans to adhere to them as a minimum standard.¹⁴ Because most MA plans already offer some form of dental benefits and use traditional private dental insurance mechanisms, we focused on the smaller and more affected group of dental care providers billing TM. We would anticipate less of an association on MA dental care providers, given MA dental coverage does not require direct federal dental care provider enrollment and billing.

These policies mark major milestones in oral health care access for certain Medicare beneficiaries. However, patients may not be able to access needed care without enough dentists participating in Medicare to provide necessary treatment. We examined whether this transition to electronic claims and the benefit expansions in 2023 and 2024 were associated with changes in dentist participation in Medicare, as measured by means of the number of billing dental care providers.

METHODS

Data were analyzed from June through September 2025. We followed the Strengthening the Reporting of Observational Studies in Epidemiology reporting guidelines.¹⁵ The Institutional Review Board determined our study to be exempt (IRB2024P003014), as it uses publicly available data sources without Health Insurance Portability and Accountability Act¹⁶ identifiers.

Data sources

We identified practicing dental care providers using the National Plan & Provider Enumeration System monthly files.¹⁷ Dental care providers are included if they have an active National Provider Identifier (NPI) number. Dentists were identified through linkage with the American Dental Association’s dentist office database on the basis of NPI number.¹⁸ The dentist office database is a comprehensive snapshot of all professionally active dentists in the United States as of the fourth quarter of each calendar year. We identified Medicare-billing dental care providers using the CMS “Doctors and Clinicians” archived data snapshots from January 2021 through December 2024.¹⁹ These snapshots, made available monthly, capture all dental care providers who actively billed a claim to TM within the previous 6 months, inclusive of the current month.²⁰

Because dental care providers with multiple Medicare-billing records, multiple specialties, or single billing records linking to multiple practice locations are listed multiple times, we restricted our sample to 1 observation per NPI number per month. Although most dental care providers had only 1 specialty, those with multiple specialties were classified so that 1 NPI number would not be associated with both a dental and nondental specialty. For example, a dental care provider enrolled as both an oral surgeon and a physician (or other specialty) was classified as an oral surgeon, and a dental care provider enrolled as both a dentist and another specialty besides an oral surgeon was classified as a dentist.

For each month, we aggregated the number of Medicare-billing dentists, Medicare-billing oral surgeons, and Medicare-billing dentists not identified as oral surgeons. We used the natural log of total number of Medicare-billing dental care providers as the dependent variable to produce percentage change estimates. We also used the total number of Medicare billing dental care providers as a dependent variable to look at raw changes in dental care provider counts. We examined all dentists and, as secondary analyses, only oral surgeons or non–oral surgeon dentists. We followed each group of Medicare-billing dental care providers monthly from January 2021 through December 2024, a total of 48 monthly observations.

Statistical analysis

Separately for all dentists, oral surgeons, and non–oral surgeon dentists, we estimated a single-group interrupted time-series analysis evaluating changes in dental care provider Medicare billing after Medicare policy changes. Each group was treated as the single treated group. We did not include a control group. Using the natural log of total Medicare-billing dental care providers in a given month and the level of total Medicare-billing dental care providers as the main target variables, we specified the following intervention dates in our model: January 2023, January 2024, and July 2024, which represent implementation months of Medicare dental policy changes. On a monthly basis from January 2021 through December 2024, we followed a cohort of all dentists, oral surgeons, and non–oral surgeon dentists exposed to these policy changes.

We estimated the following model using a Prais-Winsten and Cochrane-Orcutt generalized least-squares estimator assuming that the model errors follow an autoregressive lag 1 process and used original and transformed Durbin-Watson statistics to evaluate removal of serial autocorrelation. Our approach is described in more detail in the Appendix (available online at the end of this article).²¹ We computed robust SEs to account for any heteroskedasticity.²² We performed all analyses using Stata SE software, Version 18.0 (StataCorp LLC). Our threshold for statistical significance was set at P less than .05 and all hypothesis tests were 2-sided.

RESULTS

Sample characteristics

In Table 1, we presented the mean and median numbers of Medicare-billing dental care providers before the first Medicare policy intervention and during each subsequent policy period. Most dentists billing Medicare were oral surgeons (88.0% in the preintervention period and 83.7% by the third postintervention period). The mean number of Medicare-billing dentists declined from 2,033 (95% CI, 1,993 to 2,074) in the preintervention period to 1,615 (95% CI, 1,607 to 1,623) by the third intervention period. Similarly, the number of Medicare-billing oral surgeons declined from 1,790 (95% CI, 1,748 to 1,831) in the preintervention period to 1,351 (95% CI, 1,347 to 1,356) by the third intervention period. Among non–oral surgeon dentists, the mean number of Medicare-billing dental care providers increased from 244 (95% CI, 241 to 246) in the preintervention period to 264 (95% CI, 260 to 268) by the third intervention period. Reported median values are close in magnitude to reported means according to specialty category and intervention period.

Table 1.

Number of Medicare-billing dental care providers according to Medicare policy change intervention period.^*,^†

VARIABLE	ALL DENTISTS, NO.	ORAL SURGEONS, NO.	NON–ORAL SURGEON DENTISTS, NO.
Preintervention Period: January 2021-December 2022
Mean (SD)	2,033.2 (96.1)	1,789.6 (98.5)	243.5 (7.0)
95% CI	1,992.6 to 2,073.7	1,748.1 to 1,831.2	240.6 to 246.5
Median	2,062.0	1,815.0	242.5
First Intervention Period: January 2023-December 2023
Mean (SD)	1,825.3 (29.8)	1,563.5 (38.5)	261.8 (9.3)
95% CI	1,806.3 to 1,844.2	1,539.0 to 1,588.0	255.8 to 267.7
Median	1,819.0	1,557.5	262.5
Second Intervention Period: January 2024-June 2024
Mean (SD)	1,703.8 (49.7)	1,433.8 (47.0)	270.0 (4.1)
95% CI	1,651.7 to 1,756.0	1,384.5 to 1,483.2	265.7 to 274.4
Median	1,702.0	1,430.5	269.5
Third Intervention Period: July 2024-December 2024
Mean (SD)	1,615.3 (7.7)	1,351.3 (4.4)	264.0 (3.5)
95% CI	1,607.3 to 1,623.4	1,346.7 to 1,356.0	260.3 to 267.7
Median	1,612.0	1,349.0	263.0

^* Source. Centers for Medicare & Medicaid Services. 19

^†Data are based on monthly snapshots of Medicare-billing dental care provider data from January 2021 through December 2024.¹⁹

Policy evaluation

For the log of total Medicare-billing dental care providers and the level of total Medicare-billing dental care providers, in Tables 2 and 3, respectively, we presented the results from the single-group interrupted time-series analysis all dentists, oral surgeons, and non–oral surgeon dentists. At the implementation of the second Medicare dental benefit expansion in January 2024, there was a 0.66% associated decline (95% CI, −1.08% to −0.24%; P < .01) or total decline of 11.6 Medicare-billing dental care providers (95% CI, −19.3 to −4.0; P < .01) among all dentists. Relative to the trend from January 2023 through December 2023, there was a 0.99% associated monthly decrease (95% CI, −1.63% to −0.35%; P < .01) or total decline of 16.4 Medicare-billing dentists (95% CI, −27.6 to −5.2; P < .01) per month from January 2024 through June 2024. Relative to the trend from January 2024 through June 2024, after Medicare transitioned to electronic 837D dental claims, there was an associated 1.64% monthly increase (95% CI, 0.64% to 2.64%; P < .01) or a total increase of 27.7 Medicare-billing dentists (95% CI, 10.6 to 44.8; P < .01) per month. The cumulative monthly increase in the number of Medicare-billing dentists after July 2024 was a statistically insignificant 0.23% (95% CI, −0.26% to 0.71%; P = .356) or 3.7 billing dental care providers (95% CI, −4.5 to 11.9; P = .366). Only after Medicare transitioned to 837D electronic dental claims in July 2024 did the associated monthly decline in the log of total Medicare-billing dental care providers (Figure 1) and the level of total Medicare-billing dental care providers (eFigure 1, available online at the end of this article) stop and begin to reverse.

Table 2.

Interrupted single-group time-series analysis assessing Medicare dental policies in January 2023, January 2024, and July 2024.^*,^†

VARIABLE‡	ALL DENTISTS	ORAL SURGEONS	NON–ORAL SURGEON DENTISTS
Linear Trend, %	−0.621§	−0.732§	0.200¶
95% CI	−0.732 to −0.510	−0.856 to −0.609	0.026 to 0.374
0-1 Indicator: On or After January 2023 = 1, %	−0.645	−0.507	−1.130
95% CI	−1.536 to 0.245	−1.372 to 0.359	−3.346 to 1.086
[0-1 Indicator: On or After January 2023 = 1] × [Linear Trend], %	0.196	0.064	0.801§
95% CI	−0.066 to 0.459	−0.228 to 0.357	0.474 to 1.128
[0-1 Indicator: On or After January 2024 = 1], %	−0.658§	−0.542§	−1.723¶
95% CI	−1.079 to −0.238	−0.897 to −0.187	−3.054 to −0.392
[0-1 Indicator: On or After January 2024 = 1] × [Linear Trend], %	−0.988§	−0.911§	−1.521§
95% CI	−1.630 to −0.347	−1.467 to −0.355	−2.502 to −0.539
0-1 Indicator: On or After July 2024 = 1, %	−0.689	−0.408	−2.122
95% CI	−2.141 to 0.763	−1.60 to 0.784	−5.517 to 1.274
[0-1 Indicator: On or After July 2024 = 1] × [Linear Trend], %	1.638§	1.705§	1.203
95% CI	0.639 to 2.638	0.847 to 2.563	−0.303 to 2.708
Cumulative Postintervention Trend, %	0.225	0.126	0.683
95% CI	−0.263 to 0.713	−0.278 to 0.530	−0.108 to 1.474
Original Durbin-Watson Statistic	0.59#	0.52#	1.05#
Transformed Durbin-Watson Statistic	1.78#	1.65#	1.79#

^*Source. Centers for Medicare & Medicaid Services.19

^†Model estimated using a Prais-Winsten and Cochrane-Orcutt regression using an autoregressive lag 1 specification. Regression estimated with SEs robust to heteroskedasticity. See Appendix for full model details.

^‡Dependent variable is the log of total billing dental care providers.

^§P < .01.

^¶P < .05.

^#Value suggests model specification substantially reduced serial autocorrelation.

Table 3.

Interrupted single-group time-series analysis assessing Medicare dental policies in January 2023, January 2024, and July 2024.^*,^†

VARIABLE‡	ALL DENTISTS	ORAL SURGEONS	NON–ORAL SURGEON DENTISTS
Linear Trend	−12.56§	−13.05§	0.486¶
95% CI	−14.75 to −10.37	−15.15 to −10.95	0.073 to 0.899
0-1 Indicator: On or After January 2023 = 1	−10.87	−6.69	−2.86
95% CI	−27.96 to 6.22	−21.41 to 8.03	−8.33 to 2.60
[0-1 Indicator: On or After January 2023 = 1] × [Linear Trend]	4.92#	2.73	2.11§
95% CI	−0.289 to 10.12	−2.24 to 7.71	1.33 to 2.90
0-1 Indicator: On or After January 2024 = 1	−11.62§	−7.78§	−4.49¶
95% CI	−19.25 to −3.99	−13.42 to −2.14	−8.02 to −0.946
[0-1 Indicator: On or After January 2024 = 1] × [Linear Trend]	16.37§	−12.25§	−3.98§
95% CI	−27.59 to −5.15	−20.50 to −3.99	−6.50 to −1.46
0-1 Indicator: On or After July 2024 = 1	−10.14	−4.47	−5.61
95% CI	−34.68 to 14.41	−21.67 to 12.74	−14.69 to 3.48
[0-1 Indicator: On or After July 2024 = 1] × [Linear Trend]	27.72§	24.32§	3.18
95% CI	10.62 to 44.81	11.97 to 36.67	−0.691 to 7.05
Cumulative Postintervention Trend	3.70	1.76	1.80#
95% CI	−4.48 to 11.88	−3.94 to 7.45	−0.249 to 3.85
Original Durbin-Watson Statistic	0.58**	0.52**	1.09**
Transformed Durbin-Watson Statistic	1.72**	1.59**	1.81**

^*Source. Centers for Medicare & Medicaid Services.19

^†Model estimated using a Prais-Winsten and Cochrane-Orcutt regression using an autoregressive lag 1 specification. Regression estimated with SEs robust to heteroskedasticity. See Appendix for full model details.

^‡Dependent variable is total billing dental care providers.

^§P < .01.

^¶P < .05.

^#P < .10.

^**Value suggests model specification substantially reduced serial autocorrelation.

Figure 1.

All dentists, single-group interrupted time series with heteroskedasticity robust SEs. Model estimated using a Prais-Winsten and Cochrane-Orcutt regression using an autoregressive lag 1 specification. Dashed vertical lines at January 2023, January 2024, and July 2024 represent implementation months of Medicare dental policy changes. Study period from January 2021 through December 2024.

At the implementation of the second Medicare dental benefit expansion in January 2024, there was a 0.54% associated decline (95% CI, −0.90% to −0.19%; P < .01) or total decline of 7.8 Medicare-billing oral surgeons (95% CI, −13.4 to −2.1; P < .01). Relative to the trend from January 2023 through December 2023, there was an associated 0.91% monthly decrease (95% CI, −1.47% to −0.36%; P < .01) or total decline of 12.3 Medicare-billing oral surgeons (95% CI, −20.5 to −4.0; P < .01) per month from January 2024 through June 2024. Relative to the trend from January 2024 through June 2024, after Medicare transitioned to electronic 837D dental claims, there was an associated 1.71% monthly increase (95% CI, 0.85% to 2.56%; P < .01) or total monthly increase of 24.3 Medicare-billing oral surgeons (95% CI, 12.0 to 36.7; P < .01) after July 2024. The cumulative monthly increase in the number of Medicare-billing oral surgeons after July 2024 was a statistically insignificant 0.13% (95% CI, −0.28% to 0.53%; P = .532) or 1.8 billing dental care providers (95% CI, −3.9 to 7.5; P = .537). Only after Medicare transitioned to 837D electronic dental claims in July 2024 did the associated monthly decline in the log of total Medicare-billing oral surgeons (Figure 2), and the level of total Medicare-billing oral surgeons (eFigure 2, available online at the end of this article) stop and begin to reverse.

Figure 2.

Oral surgeons, single-group interrupted time series with heteroskedasticity robust SEs. Model estimated using a Prais-Winsten and Cochrane-Orcutt regression using an autoregressive lag 1 specification. Dashed vertical lines at January 2023, January 2024, and July 2024 represent implementation months of Medicare dental policy changes. Study period from January 2021 through December 2024.

In logs and levels, Figure 3 and eFigure 3 (available online at the end of this article) depict the evolution of Medicare-billing among non–oral surgeon dentists from January 2021 through December 2024. Among non–oral surgeon dentists, relative to the preintervention trend from January 2021 through December 2022, there was an associated 0.80% monthly increase (95% CI, 0.47 to 1.13%; P < .01) or total increase of 2.1 Medicare-billing dental care providers (95% CI, 1.3 to 2.9; P < .01) per month from January 2023 through December 2023. At the implementation of the second Medicare dental benefit expansion in January 2024, there was an associated 1.72% decline (95% CI, −3.05% to −0.39%; P = .012) or total decline of 4.5 Medicare-billing non–oral surgeon dentists (95% CI, −8.0 to −0.95; P = .014). Relative to the trend from January 2023 through December 2023, there was an associated 1.52% monthly decrease (95% CI, −2.50% to −0.54%; P < .01) or total monthly decrease of 4.0 Medicare-billing non–oral surgeon dentists (95% CI, −6.5 to −1.5; P < .01) from January 2024 through June 2024. The cumulative monthly increase in the number of Medicare-billing non–oral surgeon dentists after July 2024 was a statistically insignificant 0.68% (95% CI, −0.11% to 1.47%; P = .089) or 1.8 billing dental care providers (95% CI, −0.25 to 3.9; P = .083).

Figure 3.

Non–oral surgeon dentists, single-group interrupted time series with heteroskedasticity robust SEs. Model estimated using a Prais-Winsten and Cochrane-Orcutt regression using an autoregressive lag 1 specification. Dashed vertical lines at January 2023, January 2024, and July 2024 represent implementation months of Medicare dental policy changes. Study period from January 2021 through December 2024.

Sensitivity analysis

For all dentists, oral surgeons, and non–oral surgeon dentists, we also estimated the single-group interrupted time-series regressions using the total number of billing dental care providers per 100,000 TM enrollees as the dependent variable (eTable 1, available online at the end of this article). Overall, the results are qualitatively similar to our main specification. The cumulative monthly increase in the number of Medicare-billing dental care providers per 100,000 TM enrollees after July 2024 was also statistically insignificant, similar to our main specification. Unlike our main specification, we see 1-time increases in the number of Medicare-billing dental care providers per 100,000 TM enrollees on January 2023 and January 2024 for all dentists and oral surgeons, likely due to TM enrollees transitioning to MA at the end of each calendar year for MA plans effective on January 1 of the following year,²³ which would decrease the denominator.

As a robustness check, for all dentists, oral surgeons, and non–oral surgeon dentists, using the log of total Medicare-billing dental care providers as the target variable, to account for higher-order serial autocorrelation, we also used the ordinary least-squares estimator to estimate the single-group interrupted time series using Newey-West SEs to account for heteroskedasticity and higher-order serial autocorrelation.²² To determine the appropriate number of lags, we used the Cumby-Huizinga (CH) test.²⁴ For all dentists and oral surgeons, the CH test detected a significant P value at lag 7, and for non–oral surgeon dentists, the CH test detected a significant P value at lag 5. Nevertheless, our results were qualitatively similar to our main specification, although some coefficients were more precisely estimated (eTable 2, available online at the end of this article).

DISCUSSION

To our knowledge, we are the first researchers to examine the relationship between policies that expanded Medicare dental coverage for certain conditions and the number of dental care providers billing Medicare for oral health care services. Among oral surgeons, the expansion of dental coverage for beneficiaries with certain medical conditions in January 2023 and January 2024 was associated with a continued decline in the number of Medicare-billing dental care providers from the start of the study period. In fact, after Medicare expanded dental coverage for those with head and neck cancer in January 2024, the monthly decline in number Medicare-billing dental care providers accelerated among oral surgeons. Only after Medicare transitioned to 837D electronic dental claims did the monthly decline in the number of billing oral surgeons begin to reverse. After July 2024, among oral surgeons, there was no statistically significant monthly increase or decline in the number of billing dental care providers.

Billing behavior among non–oral surgeon dentists differs somewhat. After the first Medicare benefit expansion in January 2023, the monthly increase in the number of billing dental care providers accelerated relative to the preintervention period before 2023. However, after the Medicare dental benefit was extended to beneficiaries with additional health conditions in January 2024, the number of Medicare-billing non–oral surgeon dentists declined. However, like oral surgeons, after Medicare transitioned to 837D electronic dental claims, the monthly decline in the number billing non–oral surgeon dentists from January 2024 through June 2024 began to reverse. Overall, for non–oral surgeon dentists, implementation of the Medicare dental policy reforms after January 2023, and especially implementation of digital claims processing, could have made it more attractive for these dental care providers to participate in Medicare, although overall participation rates remain low.

To put these results in some context, the total number of US oral surgeons held steady at approximately 7,400 from 2021 through 2024.²⁵ Given this denominator, the TM billing participation rate from the preintervention period to the third intervention period after June 2024 went from 24% to 18%. During the same period, the percentage of oral surgeons participating in pediatric Medicaid programs went from 55% to 53%.²⁶ Clearly, reforms to date have not enhanced oral surgeon participation in any public dental benefit. With an extra 1.3 million people eligible for dental benefits through TM,¹² the continued decline in TM oral surgeon participation could threaten the well-being of eligible patients, leading to increased morbidity or mortality.

We hypothesized a few reasons for the persistent decline in the number of Medicare-billing oral surgeons despite Medicare dental benefit expansions in January 2023 and January 2024. First, enrolled dentists may have chosen not to continue to participate in Medicare due to concerns of pent-up demand from newly eligible patients and the possibility that Medicare reimbursement for needed procedures at high volume could be harmful to their business. Similar patterns have been observed among Medicaid-enrolled dentists.²⁷ Next, there has been historical resistance to Medicare participation among dentists, to the point of organizing against the attempt to implement a more universal Medicare dental benefit. This resistance likely stems from the lower reimbursement dentists would receive relative to private insurance. In addition, dentists have seen their counterparts in medicine face declining reimbursement in Medicare and increased regulatory burdens.²⁸ Administrative burdens such as claim denials and multiple claim resubmissions make it less likely for dental care providers to participate in public insurance than private insurance. It is estimated that physicians lose 18% of Medicaid revenue, 4.7% of Medicare revenue, and only 2.4% of commercial revenue to billing problems.²⁹ Conceivably these negative attitudes could disincentivize dental care provider enrollment, particularly due to concerns of insufficient reimbursement rates and high administrative burden.¹⁴ Many dental practices provide their own payment plans for older adults through vendors such as CareCredit, which allows patients to pay for their oral health care services through structured repayment plans.^30,31 Dentists could be reluctant to shift from this lucrative model. Lastly, low Medicare participation could be due to lack of awareness of the new policies.

To our knowledge, there has not been qualitative research exploring the reasons dentists may not participate in Medicare. Among the reasons dentists cite for not participating in Medicaid are reimbursement rates, appointment cancellations, payment denials, the claim submission process, time to payment, practice audits, staffing shortages, and burdensome enrollment processes.³² More research is needed to assess whether dentists not participating in TM or MA cite similar reasons. Manski and Lamster²⁸ suggested that Medicare set dentist reimbursement at from 65% through 75% of the usual and customary rate. This reimbursement level would be below the typical 80% of usual and customary rate for traditional preferred provider organization plans, but potentially sufficient to incentivize participation in Medicare.

We found that most dentists billing Medicare are oral surgeons. Oral surgeons are more likely to practice in tertiary care settings where Medicare enrollment and billing is standard.³³ Before the dental benefit expansions in 2023 and 2024, Medicare only covered a restrictive set of dental procedures requiring hospitalization.³⁴

It is yet to be seen whether there is a sufficient dental care provider network for Medicare beneficiaries eligible for dental coverage through this policy. Our results are limited by means of the fact that we do not have data on claims volume. Researchers should examine whether these new policies increased patient volume among existing dentists treating Medicare beneficiaries.

There are several limitations in our study. First, we explored comparing the oral surgeon cohort with a synthetic control consisting of different cohorts of medical specialties over the same period using a synthetic difference-in-differences estimator.³⁵ However, there was evidence of violation in parallel trends starting in 2022, likely associated with a new physician fee schedule that decreased total allowed charges for oral surgeons by 1% starting January 1, 2022.³⁶ Given that more than 80% of Medicare-billing dental care providers are oral surgeons, we decided to estimate a single-group interrupted time-series analysis without a control group because a suitable control cohort group was likely not available. The lack of a control group is a limitation in our analysis, as we cannot make any causal inferences, only statistical associations between the Medicare dental policy changes and the number of Medicare-billing dental care providers. Second, the billing provider data CMS “Doctors and Clinicians” archived data snapshots cover only dental care providers participating in TM. We did not have access to the number of dentists billing through MA. Third, we did not have access to dental claims data. Hence, we could not determine the types of claims dentists filed before and after the policy changes. Fourth, although Prais-Winsten and Cochrane-Orcutt generalized least-squares estimator removes substantial serial autocorrelation, there is still some residual serial autocorrelation in our model. However, given that the transformed Durbin-Watson statistic is approximately 1.7 for all models, we are confident that the presence of any residual serial autocorrelation does not invalidate any statistical inferences or point estimates. Lastly, there may be influences from seasonal variation, particularly from MA open enrollment, for which we cannot control. However, in our opinion, this mostly effects transitions in people disenrolling from TM into MA, not on the number of billing dental care providers. On the basis of the early data to which we have access, it is difficult to isolate changes in the numbers of dentists billing Medicare due to COVID-19 or other cyclical billing patterns.

CONCLUSIONS

We found new policies that allow dentists to bill to Medicare for beneficiaries with certain conditions were associated with a decrease in the number of oral surgeons participating in Medicare. These findings suggest the policies as enacted have not yet incentivized more dentists to participate in Medicare.

Supplementary Material

Supplemental material is available online.

ABBREVIATION KEY

CH

Cumby-Huizinga

CMS

Centers for Medicare & Medicaid Services

MA

Medicare Advantage

NPI

National Provider Identifier

TM

Traditional Medicare