Dental Practice Tax Deductions: Equipment, Supplies, and Every Expense You Can Write Off

Most dental practices don't miss exotic deductions; they miss ordinary ones through sloppy categorization, and they overreach on a predictable handful that examiners know to check. Here's the full landscape: what's clearly deductible, what's deductible with rules attached, what gets missed, and what gets practices in trouble.

Key takeaways

• With 100% bonus depreciation permanent and a Section 179 limit of $2.5 million (2025, indexed), essentially all equipment a private practice buys can be deducted in the year it's placed in service.
• The de minimis safe harbor lets you expense items up to $2,500 per invoice/item immediately with a simple written policy — no depreciation schedule needed for handpieces and small instruments.
• Lab fees, clinical supplies, wages, rent, malpractice premiums, software, CE, and licenses are straightforwardly deductible — the value is in categorizing them so benchmarks work.
• Retirement plan contributions are the largest single deduction available to a profitable owner — often bigger than everything else on this list combined.
• The commonly abused items — vehicles, home office, travel-wrapped CE, family wages — are all legitimately deductible when the facts are real and documented.

Equipment: the big-ticket layer

Chairs, delivery units, sensors, pan/CBCT, sterilizers, CAD/CAM mills, lasers, computers — all depreciable personal property with three routes to deduction:

Section 179 — elect to expense up to $2.5 million (2025 limit, indexed annually; phase-out begins at $4 million of purchases). Limited to business taxable income; unused amounts carry forward.

Bonus depreciation — now permanently 100% for qualifying property acquired and placed in service after January 19, 2025. No income limitation (it can create a loss), applies to used equipment that's new to you, and is automatic unless you elect out by class.

Regular MACRS — 5- or 7-year recovery for most dental equipment. Choosing MACRS (by electing out of bonus) is the underrated move for practices in low-income or loss years that expect higher brackets ahead: a deduction is worth more at 37% in year three than at 12% in year one.

Two supporting rules do quiet work. The de minimis safe harbor lets you expense any item costing up to $2,500 (per item or invoice) as supplies with a written capitalization policy in place at year start — handpieces, curing lights, small instruments never touch the depreciation schedule. And placed in service means ready and available for use, not ordered or paid for: the CBCT sitting in crates on December 31 is next year's deduction.

The everyday operating stack

All ordinary-and-necessary under IRC §162, listed here mostly so your chart of accounts captures them cleanly (see our dental bookkeeping guide for the structure):

• Lab fees — crowns, bridges, dentures, aligners. Deduct as billed; break out by type if volume justifies.
• Clinical and office supplies — composite, impression material, anesthetic, PPE, sterilization consumables.
• Wages, payroll taxes, and benefits — including associate compensation. (Owner wages in an S-corp are deductible to the practice and taxable to you — they move tax, not eliminate it.)
• Rent and occupancy — rent, CAM, utilities, repairs. Florida's sales tax on commercial rent ended October 1, 2025; if your landlord is still billing it, ask why.
• Malpractice and business insurance — deductible; see our dental insurance guide for the lines that aren't (personal disability, buy-sell life).
• Merchant and billing fees — the 2.5–3% card processing haircut is a real expense; make sure gross collections and fees are both booked rather than netted invisibly.
• Software and subscriptions — PMS, imaging, patient communication, clearinghouse fees.
• Marketing — websites, ads, sponsorships (sponsorship with advertising benefit is marketing; a pure donation is a charitable item that, for a pass-through, deducts on your personal return only if you itemize).
• Professional fees — accounting, legal, consulting.
• CE, licenses, and dues — required continuing education, DEA registration, state licenses, ADA/FDA/local society dues (note: the portion of dues attributable to lobbying is non-deductible; societies disclose the percentage).
• Interest — practice acquisition and equipment loan interest. Most practices fall under the small-business gross-receipts exception to the §163(j) interest limitation.
• Bad debts — only if you're accrual-basis (rare in dentistry). Cash-basis practices never reported the income, so there's nothing to write off — a perennially misunderstood point.

Frequently missed

Retirement plan contributions — the heavyweight. A well-designed 401(k)/profit-sharing (and, for older high earners, cash balance) combination can move $80,000–$300,000+ per year from taxable income to deferred savings. If your only "tax planning" is buying equipment in December, you're optimizing the small lever (see our dental retirement plan guide).

The QBI deduction — 20% of qualified business income for pass-through owners, phasing out for dentists (an SSTB) at higher taxable incomes. Below the threshold it's significant and requires no spending at all — just correct computation.

Startup and organizational cost amortization — the 180-month §195/§248 amortization from your opening year keeps deducting for 15 years; it falls off returns when preparers change.

Home office — legitimate for the owner who genuinely does the practice's administration from a dedicated space at home, and it unlocks business-mileage treatment for home-to-office trips that would otherwise be commuting. Modest dollars, disproportionate mileage benefit.

Health-related items routed correctly — S-corp >2% shareholder health premiums through W-2 plus the personal deduction; HSA contributions if you're on a qualifying high-deductible plan.

Augusta rule (§280A(g)) — renting your home to the practice for up to 14 days a year (board/planning meetings) at documented fair rates: deductible to the practice, tax-free to you. Fine at reasonable rates with real meetings and minutes; a favorite audit target when inflated.

Deductible, but done wrong constantly

Vehicles — deductible to the extent of business use, which for most practice owners is modest: commuting isn't business use. Contemporaneous mileage logs decide these audits. The heavy-SUV §179/bonus play requires the business-use percentage to be real.

Travel + CE — a convention in another city is deductible (registration, coach airfare, lodging, 50% of meals) when the primary purpose is professional. Adding three vacation days doesn't kill the CE deduction, but the vacation days' lodging and the family's costs are personal. Cruises and foreign conventions carry extra statutory restrictions.

Meals — 50% deductible for bona fide business meals; team meals at working meetings 50%; entertainment (games, golf, concerts) is non-deductible entirely, even with a referral source in tow.

Employing family — real wages for real work at market rates are deductible and can be excellent planning (a child legitimately doing scanning/records work shifts income to their bracket). Payroll-processed, documented, actual work. "Real work" is the entire ballgame.

Clothing — scrubs and lab coats yes; business attire wearable outside work, no, regardless of how consistently you wear it to the office.

Make the documentation boring

Every rule above resolves in your favor with the same inputs: separate business bank and card accounts, receipts captured digitally at point of sale, a written capitalization policy, mileage logs, and a bookkeeping system that puts each expense in a category you can defend. Practices with clean books don't fear these questions; practices with commingled accounts lose deductions they legitimately earned.

Official sources

• IRS Publication 334 — Tax Guide for Small Business: https://www.irs.gov/publications/p334
• IRS Publication 946 — How to Depreciate Property: https://www.irs.gov/publications/p946
• IRS — De minimis safe harbor (tangible property regulations FAQ): https://www.irs.gov/businesses/small-businesses-self-employed/tangible-property-final-regulations
• IRS — Deducting business expenses: https://www.irs.gov/businesses/small-businesses-self-employed/deducting-business-expenses

Practitioner note: The best December tax move is rarely another equipment purchase — spending $60,000 to save $22,000 only makes sense if you needed the equipment anyway. Retirement contributions save the same tax while the money stays yours. Buy equipment on clinical logic; time it on tax logic.

Fairlight's dental bookkeeping and tax preparation keeps every category clean and every election modeled — across Miami, Coral Gables, Fort Lauderdale, and greater South Florida. Contact us or see pricing.