Will Medicare Pay for Dental Work Before Chemotherapy or CAR-T? Yes, Since January 1, 2024. Here Is the Rule.

Short answer: yes. Since January 1, 2024, Medicare pays for a dental or oral exam, and treatment to eliminate infection, before or during chemotherapy, CAR-T cell therapy, or high-dose bone-modifying drugs given for cancer. That is written into 42 CFR 411.15(i)(3)(A), which CMS added in the CY 2024 Physician Fee Schedule final rule. It does not cover routine dental care that happens to fall during cancer treatment. It covers the exam and the infection work your oncology team needs done first.

This is one line inside a longer federal rule most dental offices have never billed. It sits next to the same coverage for organ transplants and heart valve surgery, all under one regulation: dental services that are "inextricably linked" to a covered medical treatment are not excluded from Medicare. Cancer treatment was on the list from day one, in 2023. Chemotherapy, CAR-T, and the bone-modifying drugs were added a year later.

What does 42 CFR 411.15(i)(3)(A) actually say about chemotherapy and CAR-T?

The subparagraph names the exact treatments. It covers a dental or oral exam "as part of a comprehensive workup prior to, and medically necessary diagnostic and treatment services to eliminate an oral or dental infection prior to, or contemporaneously with," a list that includes "chemotherapy when used in the treatment of cancer, chimeric antigen receptor (CAR) T-cell therapy when used in the treatment of cancer, and administration of high-dose bone-modifying agents (antiresorptive therapy) when used in the treatment of cancer."

Three things are covered by that sentence: the exam, and the infection treatment that comes out of it, done before your chemo or CAR-T starts, or around the same time. The subparagraph also names organ transplant, stem cell and bone marrow transplant, cardiac valve replacement, and valvuloplasty in the same list. It is one rule with several triggers.

Why did Medicare add chemotherapy and CAR-T to this rule in 2024?

The original version of this regulation, in force since January 1, 2023, already covered dental clearance before transplants and heart valve surgery. CMS extended it to chemotherapy, CAR-T, and high-dose bone-modifying agents in the CY 2024 Physician Fee Schedule final rule, CMS-1784-F, effective January 1, 2024. CMS pointed to research on the risk that an untreated oral infection carries during cancer treatment: it can turn into a serious, sometimes fatal, complication once chemotherapy or CAR-T suppresses the immune system.

High-dose bone-modifying agents, drugs like zoledronic acid or denosumab given at cancer doses, carry a separate, well-documented risk: medication-related jaw bone problems. An exam and any needed infection treatment before the drug starts is standard oncology practice. As of 2024, Medicare pays for that dental visit as part of the cancer treatment, not as a dental benefit.

What exactly is covered before chemo or CAR-T, and what is not?

What Medicare covers	What Medicare does not cover
The dental or oral exam before chemotherapy, CAR-T, or high-dose bone-modifying drugs start	A cleaning done at the same visit, unless it is the infection treatment ordered
Treatment to eliminate an active oral or dental infection before or during that cancer treatment	Fillings, crowns, or a bridge, even if scheduled around the same time
The same exam and infection treatment done contemporaneously with the cancer treatment	Dental work done later, with no connection documented to the cancer treatment
Anesthesia, x-rays, and OR time furnished as part of the covered dental service	Dentures or implants to restore chewing after treatment ends

The word doing the work in the regulation is "prior to, or contemporaneously with." The exam and the infection treatment have to sit on that timeline, next to the cancer treatment. A dental visit with no documented connection to your oncology care is still routine dental work, cancer diagnosis or not.

Why do these claims get denied even when the patient clearly qualifies?

We read a lot of these denials. The pattern repeats. The dental work was real, the cancer treatment was real, and the claim still came back denied. Three reasons account for nearly all of it.

The claim was filed as ordinary dental work. If the dentist's office bills a cleaning or an exam without noting the connection to chemotherapy or CAR-T, Medicare has no way to know this claim is different from any other dental bill. The Medicare Summary Notice will show a routine dental denial, with nothing about your cancer treatment on the page.

The referral or documentation is missing. Medicare requires that the connection between your oncologist and your dentist be documented, not assumed. A referral letter, a chart note that the oncology team requested a pre-treatment dental clearance, or records shared between the two offices. Without that paper trail, the claim looks unconnected even when the timing is exact.

The KX modifier and diagnosis code are missing. Since July 1, 2025, a dental claim in this category must carry the KX modifier, the dentist's certification that documentation supports the link, and an ICD-10 diagnosis code identifying the cancer treatment. A claim submitted without both is filed incorrectly, regardless of whether you actually qualified.

How do I get this covered before my chemotherapy or CAR-T starts?

If your oncology team has told you to get cleared by a dentist first, do these three things in order, before the dental appointment if you can.

1. Ask your oncologist's office for a short written referral naming the chemotherapy, CAR-T, or bone-modifying drug you are starting, and stating that dental clearance is needed first.
2. Ask the dental office directly: "Are you enrolled in Medicare, and will you bill this with the KX modifier and my diagnosis code?" A dentist who is not enrolled in Medicare cannot bill Medicare for this, no matter how clearly the treatment qualifies.
3. Keep the referral, the dental notes, and the itemized bill together. If the claim is denied anyway, that folder is the appeal.

What if I already paid, or the claim was already denied?

You can still be paid back. Medicare's Patient Request for Medical Payment, form CMS-1490S, lets you submit the itemized bill and the dentist's notes yourself, with your oncologist's referral attached, to your Medicare contractor. The dentist generally still needs to be enrolled in Medicare for the claim to pay.

If the claim was denied, you have the right to a redetermination under Original Medicare, within 120 days of the date on your Medicare Summary Notice. In the appeal, name the subparagraph that applies, chemotherapy, CAR-T, or high-dose bone-modifying agents under 42 CFR 411.15(i)(3)(A), attach the oncology referral, and ask the dental office to correct the claim if it went in without the KX modifier or a diagnosis code. Many of these denials are paperwork problems, not coverage problems.

A note on who we are

CheckMyDenial helps patients read and appeal insurance denials. We are related to a company that does medical-dental billing and reimbursement for patients and practices, and if you ever move from reading to having someone handle a claim for you, that relationship and any fee are disclosed before anything is paid. This page is free, it does not require anything from you, and it will stay that way.

Where this comes from

Everything above is drawn from 42 CFR 411.15(i)(3)(A) and from the CMS Medicare Dental Coverage page, which lists the scenarios and the KX modifier and diagnosis-code dates. Chemotherapy, CAR-T cell therapy, and high-dose bone-modifying agents were added to the rule by the CY 2024 Physician Fee Schedule final rule, CMS-1784-F, effective January 1, 2024. Links are listed at the end of this page. If you find something here that is out of date, tell us and we will fix it and change the date at the top.