Year-End Tax Checklist for Dental Practice Owners

The dentists who pay the least tax in a given year are not the ones who called their CPA on December 28. They are the ones who had a substantive planning conversation sometime between July and October, when there was still time to act. By the time you are watching the ball drop, the window on most meaningful moves has already closed.

This checklist is not about obscure strategies. It is about the handful of decisions that carry real dollar weight for a typical dental practice owner and that require a deliberate choice before year-end. Work through these with your advisor while you still have runway.

Entity Structure and Compensation: Are You Still Set Up Correctly?

Your entity structure is not a set-it-and-forget-it decision. An S corporation that made sense when you were producing at one level may be leaving money on the table, or creating unnecessary payroll exposure, as your income grows or changes.

The core question for an S-corp dental owner is whether your W-2 salary is set at a reasonable level given your actual duties and production. The IRS expects S-corp owner-employees to pay themselves a salary commensurate with what the practice would pay someone else to do the same work. Set it too low and you have audit exposure. Set it higher than necessary and you are paying self-employment or payroll taxes you did not have to pay.

Before year-end, review:

• Whether your current reasonable compensation analysis still reflects your clinical and administrative role
• Whether a year of higher distributions relative to salary has created a ratio that looks aggressive
• Whether your entity structure (sole proprietor, partnership, S-corp, or C-corp) still fits your income level, state tax situation, and exit timeline
• If you added an associate, partner, or DSO arrangement, whether your entity structure still makes sense

This is not a conversation to have in December. If a structure change is warranted, it almost always requires advance planning and cannot be retroactively applied to the current year.

Equipment Timing: Spend It or Wait?

Section 179 expensing and bonus depreciation allow dental practices to deduct the cost of qualifying equipment in the year placed in service rather than depreciating it over several years. That timing distinction can matter significantly depending on where your income lands this year versus next.

The operative question is not simply "should I buy equipment." It is "should I buy and place in service this equipment before December 31, or does it actually benefit me to push it into January?"

Situations where accelerating an equipment purchase into the current year makes sense:

• Your practice income is running materially higher than last year and you want to offset a larger tax liability
• You are in a higher bracket this year than you expect to be next year
• You have been considering the purchase anyway and the equipment will genuinely be in service before year-end

Situations where waiting until January may be smarter:

• Your income is lower this year and you expect a higher-income year ahead
• You are planning a major income event early next year (a sale, a buyout, a large case collection surge) and the deduction will be worth more in that year
• Year-end delivery and installation cannot realistically be completed before December 31, meaning the deduction does not attach to this year anyway

Do not let a vendor's year-end sales push drive a tax decision. The depreciation benefit is only useful if it hits the right year.

Retirement Plan Funding and Deadlines

This is the highest-leverage, cleanest tax reduction tool available to a dental practice owner, and it is the one most commonly under-utilized.

The general landscape:

• A SEP-IRA can be established and funded up to the extended due date of your tax return, giving flexibility even after year-end
• A SIMPLE IRA must have been established earlier in the year (generally by October 1 for new plans) and employee contribution deadlines are tied to payroll
• A Solo 401(k) or practice 401(k) must be adopted by December 31 of the tax year for which you want to make contributions (even though funding can follow later)
• Defined benefit and cash balance plans have actuarial setup requirements and must generally be established before year-end

The practical point: if you do not have a retirement plan or your current plan is capped at a contribution level that is not absorbing much of your income, the fall is the time to explore whether a different plan type could shelter meaningfully more. A dentist in peak earning years with a solo or small-group practice who is in a high bracket and behind on retirement savings is almost always leaving a material deduction on the table by staying in a low-ceiling plan.

Have your advisor model the contribution ceiling and the after-tax cost under your likely bracket before year-end, not in February when you are preparing returns.

Estimated Tax True-Up: Avoid the Penalty, Avoid Overpaying

Most dental practice owners pay quarterly estimated taxes. By the time Q3 or Q4 arrives, you have enough data to know whether your estimates are tracking your actual liability.

Two failure modes to address before December 31:

Underpayment. If collections were stronger than projected, your estimates may be short. The IRS imposes an underpayment penalty when you fall below certain safe harbor thresholds. Review your year-to-date income against what you estimated and make up any shortfall in Q4 rather than absorbing both the penalty and a large surprise balance due in April.

Overpayment. Writing large checks to the IRS and waiting months for a refund is an interest-free loan you are giving the government. If your income came in below projections, there is no tax benefit to overpaying. Calibrate Q4 accordingly.

Your advisor should be doing this projection with you in October or November, using actual year-to-date numbers, not last year's return.

Deferral vs. Acceleration of Income: Which Direction Fits This Year?

The general planning framework is to defer income into a lower-tax year and accelerate deductions into a higher-tax year. But that default logic does not always apply to dental practice owners, and blindly following it without understanding your specific situation can backfire.

Reasons to consider deferring income into next year:

• You expect your bracket or effective rate to be lower next year (income declining, large deductions expected, business sale creating a unique year)
• Tax law changes are anticipated that would lower rates next year

Reasons to consider accelerating income into this year:

• You expect a higher-rate environment next year (rate increases under current law or anticipated legislation, partner buyout income, expansion that pushes income up)
• You have losses, deductions, or credits this year that will offset the income but that you cannot carry forward effectively

For a dental practice on a cash basis, the practical levers for timing include when you deposit payments, whether you send year-end patient billing statements, and when you recognize certain fee income. Talk to your advisor about which direction fits this specific year before either of you defaults to the usual approach.

FAQ

When should I start year-end planning with my CPA? Ideally between July and October. Meaningful actions, such as plan adoption, entity changes, and equipment decisions, require time to execute.

Does my S-corp salary affect my QBI deduction? Yes. Your qualified business income deduction for a dental practice may be affected by W-2 wages paid, among other factors. Salary level and QBI interact in ways that require modeling specific to your numbers.

Can I establish a retirement plan after December 31 and still get the deduction this year? It depends on the plan type. SEP-IRAs have more flexibility. 401(k) and defined benefit plans generally require adoption by December 31. Confirm specifics with your advisor well before year-end.

What if my income is highly variable year to year? Variable income makes planning more valuable, not less. It also makes the timing of deductions and income recognition more consequential. Model multiple scenarios.

This article is general educational information and does not constitute tax advice for your specific situation. Consult a qualified tax advisor before making decisions.