Your FSA dollars expire December 31 — what a dental visit actually covers

If you have a flexible spending account (FSA) through your employer and there are dollars sitting in it that you have not used, the next four weeks are the window. The deadline is December 31 for most plans, and most dental work qualifies.

Here is what your FSA actually covers, what it does not, and how to use it before the balance disappears.

The rule that matters

FSA balances generally forfeit at the end of the plan year. Most plans run on the calendar year, which means anything you have not spent by December 31 vanishes back to your employer. The IRS allows two exceptions, but your employer chooses which (if any) to offer:

• Carryover. Some plans let you roll up to $660 (the 2025 carryover limit) into the next plan year. Read your plan documents — many do not offer this.
• Grace period. Some plans give you an extra 2.5 months (until March 15 of the next year) to incur expenses against the prior year's balance. Again, not all plans offer this.

If neither of these applies to your plan, December 31 is a hard deadline. The dollars are use-it-or-lose-it.

What dental procedures qualify

The list is broader than most patients realize. FSA-qualified dental expenses include:

• Routine cleanings, exams, and X-rays
• Fillings (composite or amalgam)
• Crowns, inlays, onlays
• Root canals and post-root-canal restorations
• Bridges and partial dentures
• Dental implants (the surgery, the post, and the crown)
• Sealants and fluoride treatments (yes, for adults too)
• Periodontal (gum disease) treatment
• Orthodontics — including the down payment on a new treatment plan and ongoing monthly fees
• Extractions, including wisdom teeth
• Nightguards prescribed for bruxism or TMJ
• Oral appliances prescribed for sleep apnea (when billed to medical, this is HSA-qualified; when paid out of pocket, FSA may cover)

What does not qualify

The line is medical necessity. Procedures done purely for cosmetic reasons do not qualify:

• Tooth whitening (in-office or at-home kits)
• Veneers placed for purely aesthetic reasons (veneers for structural restoration of a damaged tooth may qualify with a written rationale from your dentist)
• Cosmetic dental bonding without a functional indication
• Over-the-counter dental products (toothpaste, mouthwash, electric toothbrushes, water flossers — these are personal care, not medical expenses)

The gray area is bigger than most patients expect. If you are unsure whether a procedure qualifies, your dentist can write a Letter of Medical Necessity that documents the functional indication, and the FSA administrator will usually accept it.

The orthodontic trick

If you have been thinking about ortho — whether traditional braces or clear aligners — and you have FSA dollars about to expire, talk to your dentist about a December down payment. Many practices will accept a deposit against an ortho treatment plan that does not actually start until January or February, and the deposit qualifies as a 2025 expense against your 2025 FSA balance.

This is not aggressive tax planning. It is how the rule is designed: the expense is incurred when you pay it, not when the service is delivered, for ortho specifically because of the long treatment timeline.

The HSA distinction

If you have an HSA (Health Savings Account) instead of or alongside an FSA, the rules are different and in your favor:

• HSA balances roll over indefinitely. There is no use-it-or-lose-it deadline.
• The 2025 HSA contribution limit is $4,300 individual / $8,550 family, with a $1,000 catch-up if you are 55+.
• The same dental procedures qualify under HSA as under FSA.

The reason this matters: if you have an HSA and you have not used your dental coverage's annual maximum this year, December is still a good month to do work — not because of FSA pressure, but because your dental benefits (typically $1,500–$2,500 in coverage per year) also reset January 1. Two pools of money to apply against the same visit.

Your December calendar

If you want to use FSA dollars at your dentist, work backwards from December 31:

• This week: Call your dentist and ask what the next 3–4 weeks look like. Most practices fill their last two December weeks within seven days of opening them.
• By December 15: Be in the chair for the procedure. This gives the dentist time to bill, gives your insurance time to process, and gives you time to submit any FSA reimbursement requests if your plan requires them.
• Before December 31: Submit any reimbursement requests. Some FSA plans require submission by year-end; others give you until March 31.

The number one reason patients lose FSA money is that they wait until December 28 to think about it. By then their dentist is booked through New Year's. If you have dollars to spend, the next week is the time to make the call.