Dentist S-Corp Tax Planning: Entity Choice, Reasonable Compensation, and the Equipment Depreciation Stack

Why the S-corp dominates dental practice entity selection

Most dentists I’ve worked with come in operating as a sole proprietorship, an LLC taxed as a partnership (with the spouse), or a single-member LLC. A small minority are already S-corps. Almost none should be C-corps.

The S-corp wins for two reasons. First, the self-employment tax savings on the K-1 distribution portion of income. Second, the planning flexibility around retirement plans, accountable plans, and entity-level state tax elections.

Sole proprietor math. Schedule C net income flows directly to the dentist. Full self-employment tax: 15.3% on the first $176,100 of net SE earnings (2025 Social Security wage base; projected $182,400 for 2026), then 2.9% Medicare uncapped, plus 0.9% additional Medicare tax above $200K single / $250K MFJ. For a dentist netting $600K, the SE tax bite is roughly $30,000-$33,000 annually.

S-corp math. The dentist pays themselves a W-2 salary out of the S-corp. The rest passes through as K-1 distribution. FICA (Social Security + Medicare) applies only to the W-2 portion. K-1 distributions escape the 15.3% SE tax (though they’re still subject to regular income tax).

Example. Dentist nets $600K. As sole prop: SE tax $32K, federal income tax at 35% marginal on the income, plus state. As S-corp paying $200K W-2 / $400K K-1 distribution: FICA on the $200K W-2 (roughly $15K split between employee and employer sides), no SE tax on the $400K K-1. Direct payroll tax savings: roughly $15K-$18K annually.

Times 20 years of practice ownership: $300K-$360K of payroll tax savings just from the S-corp structure. Plus compounding if the savings get invested.

Entity selection step by step.

Step 1: Form an LLC or professional LLC (PLLC) under your state’s law. Many states require dental practices to be PLLCs or professional corporations (PCs) — check state-specific rules. Filing fees typically $200-$1,000 depending on the state.

Step 2: File Form 2553 with the IRS to elect S-corporation tax treatment. Must be filed within 2 months and 15 days of the start of the tax year you want the election to apply, or get late election relief under Rev. Proc. 2013-30 (which works if filed within 3 years and 75 days).

Step 3: Open a separate business bank account for the S-corp. All practice income flows in, all practice expenses flow out. Don’t commingle.

Step 4: Set up payroll for yourself. Use Gusto, ADP, or a similar service. W-2 yourself monthly or bi-weekly. Run the federal income tax withholding, FICA, and state withholding through payroll.

Step 5: At year-end, the S-corp files Form 1120-S. The dentist receives a K-1 reporting the pass-through K-1 income. Personal return picks up the K-1 income on Schedule E.

Step 6: Run year-end accountable plan reimbursements for legitimate business expenses paid personally (more on this below).

What about the spouse? Many dentists put the spouse on the S-corp payroll for administrative work (insurance billing, scheduling, bookkeeping). The spouse’s W-2 establishes a separate income for retirement plan contributions and Social Security earnings record. The spouse W-2 should reflect actual work performed at a market rate. Documentation matters.

Don’t elect S-corp until net income justifies the administrative cost. For a hygienist part-timer or a new associate netting $80K, the sole prop or single-member LLC is simpler. Crossover point is typically $80K-$120K of net practice income, where the SE tax savings start exceeding the administrative complexity. Most established dental practices clear $300K+ where S-corp is clearly the right answer.

Reasonable compensation — the BLS benchmark and the IRS challenge

Reasonable compensation is the single biggest IRS audit risk for dental S-corps. The IRS pays attention to the W-2 / K-1 split. Pay yourself $40K W-2 out of an S-corp generating $500K of net income and you’re going to lose if audited.

The legal standard. The S-corp owner-employee must pay themselves ‘reasonable compensation’ for services rendered. The remaining S-corp income can be K-1 distribution. Reasonable compensation is what an outside professional with comparable training, experience, and responsibilities would earn for similar services.

IRC §162(a)(1) establishes the deduction standard for ordinary and necessary business expenses including reasonable compensation. The IRS uses a multi-factor test from IRS guidance on S-corp owner compensation: – Training and experience – Duties and responsibilities – Time and effort devoted to the business – Dividend history – Payments to non-shareholder employees – Timing and manner of paying bonuses to key people – What comparable businesses pay for similar services – Compensation agreements – Use of the formula to determine compensation

Court cases. Watson v. Commissioner, 668 F.3d 1008 (8th Cir. 2012) is the leading case. Watson was a CPA who paid himself $24K W-2 out of an accounting firm generating $200K+ of net income. The Tax Court reallocated $67K from K-1 distributions to W-2, assessing additional FICA, penalties, and interest. The case established that reasonable comp must reflect industry benchmarks for similar services.

Rev. Rul. 75-50 (older but still relevant) addresses the related issue of whether dividends should be reallocated to compensation when a corporation pays disproportionate dividends to shareholder-employees relative to their compensation for services.

Benchmarks for dentists. BLS Occupational Employment Statistics median wage for dentists (general practice) was approximately $170,000-$200,000 for 2024 (varies by region). For specialists: – Orthodontists: $200,000-$320,000 – Oral and maxillofacial surgeons: $239,000-$400,000+ – Pediatric dentists: $180,000-$250,000 – Periodontists: $200,000-$300,000 – Endodontists: $250,000-$350,000 – Prosthodontists: $180,000-$250,000 The American Dental Association Health Policy Institute publishes annual practice surveys with more detailed compensation data. ADA member dentists can access detailed regional and specialty data.

Practical reasonable comp guidelines. For a general dentist owner clearing $500K of net income, paying $180K-$220K W-2 is defensible. For $700K of net income, $230K-$280K W-2. For an oral surgeon at $1M of net income, $350K-$450K W-2.

Rule of thumb: 35-45% of net income to W-2 is a safe zone for a dentist owner who is the primary practitioner. Could be higher (50-60%) for a dentist who is essentially the only producer and does no business management — the more your time is direct clinical, the higher the comp should be.

Could be lower if you have an associate dentist generating a substantial portion of practice revenue (the associate’s production is partly compensation to them, not to you). Document the production splits.

Documentation supporting the comp. – Annual board resolution setting the salary – Compensation study comparing to BLS, ADA, or local market data – Job description listing the dentist’s responsibilities – Time allocation analysis (hours of clinical vs. management vs. ownership) – Industry surveys or benchmarking reports Keep these in the corporate records. If audited, this documentation goes to the IRS examiner. Strong documentation typically ends the inquiry.

The reverse problem — paying too much. Some dentists pay themselves 100% of net income as W-2 to make the most of Social Security earnings or to fund a 401(k). This isn’t necessarily wrong but it gives up the SE tax savings benefit of the S-corp. For a young dentist building a Social Security earnings record, higher W-2 might be justified. For an established dentist near retirement, lower W-2 / higher K-1 is more tax-efficient.

PTET workaround for SALT cap. State pass-through entity tax elections (PTET) let the S-corp pay state income tax at the entity level, providing a federal deduction (working around the $10K SALT cap). The PTET payment is deductible on Form 1120-S. The shareholder gets a credit on the personal state return for the PTET paid. For dentists in high-tax states (CA, NY, NJ, MD, OR), PTET typically saves $4K-$20K of federal tax annually depending on income.

§179 and bonus depreciation — cone-beam CT, CAD-CAM, and the timing game

Dental practices are equipment-intensive. Cone-beam CT systems run $80K-$200K. CAD-CAM mills (Sirona, Planmeca) run $100K-$200K. Digital scanners $20K-$50K. Operatory chairs and units $20K-$40K each. A new practice fit-out can hit $400K-$700K of equipment plus build-out.

IRC §179 allows immediate expensing of qualifying property up to the annual limit ($1.16M for 2024, indexed annually). The deduction phases out dollar-for-dollar above the §179 acquisition threshold ($2.89M for 2024). For most dental practices, the limit is high enough to cover the full year’s equipment purchases.

IRC §168(k) bonus depreciation allows immediate expensing of a percentage of qualifying property: – 100% for property placed in service before January 1, 2023 – 80% for property placed in service in 2023 – 60% for property placed in service in 2024 – 40% for property placed in service in 2025 – 20% for property placed in service in 2026 – 0% for property placed in service in 2027 and beyond (unless Congress extends) The phase-down was scheduled under TCJA but legislation is pending to extend or restore 100% bonus depreciation. Confirm current status for the year of purchase.

Strategy: stack §179 and bonus depreciation. §179 has business income limitation (can’t generate a loss). Bonus depreciation can generate a loss. For a profitable practice with $500K of net income before depreciation, both stack to give 100% immediate expensing on most equipment.

Example. Dentist buys $150K cone-beam CT in 2026. §179 deduction: up to $150K (subject to overall §179 limit and business income limitation). Or bonus depreciation: 20% of $150K = $30K immediate plus $120K spread over 5-year MACRS recovery. Or mix: §179 some portion and bonus + MACRS the rest.

For 2026 acquisitions, §179 is generally better than bonus depreciation since bonus is only 20%. For 2025 and earlier, the bonus rates were higher and the mix question was more interesting.

Section 179 vehicle limits. Vehicles weighing more than 6,000 lbs gross vehicle weight rating qualify for partial §179 treatment. Common dental practice vehicles in this range: full-size SUVs, large pickup trucks, vans used for practice transport. §179 deduction on heavy SUVs is capped at $30,500 for 2024 (indexed up). Bonus depreciation can be claimed on the excess.

Lighter passenger vehicles have stricter §280F limits — first-year depreciation capped at $20,400 for 2024.

Building improvements and qualified improvement property (QIP). Interior improvements to nonresidential buildings (after the building is placed in service) qualify as QIP under IRC §168(e)(6). QIP is 15-year MACRS property and qualifies for §179 and bonus depreciation. Dental office build-outs (new operatories, utility infrastructure for new equipment, plumbing modifications, electrical) generally qualify.

Roof, HVAC, fire alarm and security systems on nonresidential property also qualify for §179 after TCJA.

Section 179 election. Made on Form 4562 Part I. Identify the property, basis, and elected deduction amount. Once made, the §179 election is generally irrevocable for the year.

Practical year-end strategy. Plan equipment purchases for year-end if you have a high-income year. Cone-beam CT delivered December 28, 2026 (and placed in service before December 31) generates immediate deduction in 2026. Delivered January 2, 2027 — deduction is in 2027.

But the equipment must actually be placed in service (operational) by year-end. Just paying for it isn’t enough. Vendor shipping delays can push ‘placed in service’ into the next year.

Cash flow consideration. §179 generates a tax deduction but doesn’t generate cash. You’re spending money on equipment. For practices financing the equipment purchase, the equipment expense is immediately deductible while the loan principal is paid over 5-7 years. Mismatch creates short-term cash flow tightness in year 1 (full deduction, full year-1 payments) that improves in years 2-7 (partial deduction taken in year 1, full payments continuing).

Don’t buy equipment you don’t need just for the deduction. The deduction is worth 35-45% of the purchase price (combined federal + state marginal). You’re still paying 55-65% of the cost out of pocket. Buy what the practice actually needs to operate or grow.

The §199A SSTB phase-out for dentists — and the carve-outs that survive

Dentistry is health under IRC §199A(d)(2)(A). SSTB. The 20% qualified business income deduction phases out for SSTB owners above the income threshold.

2026 thresholds (projected from 2025 figures, indexed annually under Rev. Proc. 2024-40): – Single: phase-in $241,950 to $291,950 – MFJ: phase-in $483,900 to $583,900 Above the upper threshold, no §199A deduction on SSTB income.

Most established dentists are above the threshold. A solo general dentist netting $500K+ of S-corp K-1 income is above the MFJ threshold (assuming spouse income or single filer). No §199A on the dental practice income.

The income reduction strategy. For dentists at the borderline (MFJ taxable income $450K-$520K), aggressive retirement plan funding can drop taxable income below the threshold and restore the §199A deduction on any non-SSTB QBI.

Example. Dentist MFJ taxable income $530K (just above the upper phase-out at $583,900? Actually below — let’s recompute). Dentist MFJ taxable income $560K. Above the lower threshold ($483,900) but below the upper ($583,900). In the phase-in range. Applicable percentage: 1 – (76.1/100) = 23.9% of the otherwise-allowed deduction. If dentist contributes $80K to a cash balance plan plus $46K to solo 401(k) plus $8.7K to HSA, taxable income drops by $134.7K to $425K. Below the lower threshold. Full §199A deduction available on any non-SSTB QBI. For the SSTB dental practice income itself, the deduction is still subject to the phase-out math, but if taxable income is below the threshold, the dental practice QBI qualifies for the full 20% deduction (subject to wage and UBIA limits, which become active at the threshold).

What non-SSTB carve-outs exist for dentists?

Non-SSTB carve-out 1: Dental real estate. A dentist who owns the building where the practice operates and rents to the practice has rental income that’s NOT SSTB. Real estate is not specified service business.

Structure. Dentist forms a separate LLC to own the building. The LLC leases the building to the dental practice S-corp at arm’s-length market rent. Rental income on Schedule E (or LLC return) is non-SSTB QBI if it qualifies as a §162 trade or business.

The rental needs to rise to the level of a §162 trade or business. A single triple-net lease (where the tenant pays all expenses including taxes, insurance, maintenance) often doesn’t qualify because it’s too passive. Multiple properties, active management, or the 250-hour rental real estate safe harbor in Rev. Proc. 2019-38 help.

Self-rental rules. IRC §469(c)(7) and related regulations treat self-rentals (rent paid by your own business to your own rental property) as non-passive — same activity grouping. This is generally good for the dentist (avoids passive loss limitations) but the §199A treatment of self-rental income has its own rules. Final regulations under Treas. Reg. §1.199A-1(b)(14) treat self-rental income as qualifying for §199A if it’s rented to a commonly-controlled trade or business.

Result: dentist’s self-rental income is QBI eligible for §199A, treated as if from the same trade or business as the SSTB dental practice (so SSTB rules apply to the rental income too — phased out above the threshold).

Non-SSTB carve-out 2: Hygienist-only corp. Some practices structure a separate entity that employs hygienists and provides hygiene services. The argument: hygiene services aren’t ‘practice of dentistry’ (which requires a dentist’s license). The hygienist corp might be non-SSTB.

This is aggressive. Treas. Reg. §1.199A-5(c)(2) treats services that are essential to or directly support the SSTB business as SSTB. Hygiene services in a dental practice are likely treated as part of the SSTB dental practice. Don’t rely on this structure without a tax opinion.

Non-SSTB carve-out 3: Dental product sales. A dentist who sells dental products (whitening kits, electric toothbrushes, mouthguards) to patients or to other practices has product sales income, which is not SSTB. If structured as a separate entity selling products to dentists rather than providing dental services to patients, it might qualify as non-SSTB.

Practical question: how much of the dentist’s income is genuinely non-SSTB? For most dentists, virtually 100% is SSTB. The carve-outs are small slivers.

Non-SSTB carve-out 4: Multi-location with separate non-clinical services. A larger dental practice with central administration (billing, IT, HR) might separate the administrative function into a non-SSTB management entity. The clinical practices pay the management entity for services. The management entity has non-SSTB income. IRS has scrutinized these ‘management company’ structures. Treas. Reg. §1.199A-5(c)(2) requires the management company to perform services that are sufficiently independent of the SSTB business. Most management companies that serve only related practices fail this test. Document the structure carefully. Get a tax opinion. Don’t claim §199A on management company income that’s basically just shifting dental practice income to a different entity.

Conclusion. For most established dentists, §199A is unavailable on practice income due to the SSTB phase-out. Focus on the legitimate non-SSTB streams (separately owned real estate, genuine product sales businesses) and accept that the deduction isn’t part of the primary tax strategy.

Form 8995-A (for taxpayers above the threshold or with SSTB income) is the §199A computation form. Schedule B handles the SSTB phase-out math.

Accountable plan — reimbursing CE, home office, and vehicle through the S-corp

Post-TCJA, unreimbursed employee business expenses are not deductible (the 2% AGI miscellaneous deduction was eliminated). So if you pay $5K of continuing education out of pocket as an employee of your own S-corp, you can’t deduct it on Schedule A.

Solution: the accountable plan. IRC §62(c) and Treas. Reg. §1.62-2 establish accountable plan rules. Under an accountable plan, the S-corp reimburses the employee (you) for business expenses. The reimbursement is excluded from the employee’s wages and the S-corp deducts the expense.

Three requirements for an accountable plan reimbursement: 1. Business connection — the expense must be paid in connection with services performed as an employee 2. Substantiation — the employee must substantiate the expenses to the employer within a reasonable time (typically 60 days) 3. Return of excess — any advance not used for substantiated business expenses must be returned within a reasonable time (typically 120 days) If all three requirements are met, the reimbursement is not income to the employee and is deductible by the S-corp. Win-win.

Set up the accountable plan. The S-corp adopts a written accountable plan (board resolution and policy document). The plan describes the categories of reimbursable expenses, the substantiation procedure, and the timing requirements.

Categories of reimbursable expenses for a dentist S-corp.

Home office. Allocated portion of home utilities, internet, homeowner’s insurance, and depreciation/rent based on square footage used for business. A dentist who spends 150 square feet of a 2,500 square foot home on records review, case planning, and admin work allocates 6% of home expenses. On $40K of annual home expenses, that’s $2,400 reimbursed pre-tax.

Vehicle expenses. For business-use vehicles, either standard mileage rate (67 cents/mile for 2024, indexed up) or actual expenses (gas, insurance, depreciation, registration). Document business miles with a log (date, destination, business purpose, miles). Common business miles for dentists: between practice locations, to CE conferences, to dental supply houses, to professional meetings.

Continuing education (CE). Registration fees, travel, lodging, meals (50% deductible) for CE conferences. ADA Annual Session, AGD MasterTrack, AACD, ICOI, and similar continuing education events. CE is mandatory for license renewal so the business purpose is clear. Tracking and reimbursement through the accountable plan converts a $4K-$10K annual expense into a pre-tax deduction.

Professional dues. ADA, AGD, AACD, state dental society, specialty organizations. Annual dues range $500-$3K per organization. All reimbursable.

Journals and publications. Dental publications, professional journals, books for the practice library.

Phone and internet. Business use percentage. A dentist who uses their cell phone primarily for patient calls, lab communication, and practice management can reimburse 50-80% of the cell phone bill.

Computer and software. Practice management software, imaging software, productivity software used for the practice. The home computer if used for business.

Health insurance premiums (for S-corp shareholders). Premiums paid by the S-corp on behalf of a 2%+ shareholder must be added back to W-2 wages (not eligible for accountable plan exclusion) but are deductible as self-employed health insurance on the personal return (Schedule 1, Line 17). Net result: premium effectively excluded from income for federal purposes but FICA applies. IRS Notice 2008-1 covers this treatment.

Documentation flow. Dentist pays personally for CE conference ($2,500). Submits expense report to S-corp within 60 days with receipt and business purpose statement. S-corp reimburses $2,500 to dentist. S-corp books $2,500 as CE expense (deductible). Dentist receives $2,500 not added to W-2 wages.

Calculate the savings. Total accountable plan reimbursements for a typical established dental practice: $10K-$25K annually across all categories. At 45% combined federal+state marginal rate, that’s $4,500-$11,250 of annual tax savings just from running the accountable plan properly.

Don’t skip this. It’s the simplest, lowest-risk dentist S-corp tax planning move and it saves real money.

Associate dentist classification — 1099 versus W-2 risk

Adding an associate dentist is a major practice growth move. The classification — independent contractor (1099) vs. employee (W-2) — has significant tax consequences for both the practice and the associate. Misclassification can lead to back taxes, penalties, and interest.

The general rule. The associate is an employee (W-2) if the practice controls when, where, and how the associate works. The associate is an independent contractor (1099) if the associate has substantial autonomy.

The IRS 20-factor common-law test (now consolidated into three categories — behavioral control, financial control, type of relationship) is used to determine classification. Specific factors for dentists:

Behavioral control factors that suggest EMPLOYEE: – Practice sets the associate’s schedule – Practice provides training – Practice requires the associate to use specific equipment, materials, and protocols – Practice supervises the associate’s work – Practice provides the office, support staff, and supplies

Behavioral control factors that suggest CONTRACTOR: – Associate sets own schedule – Associate uses own equipment (rare in dentistry) – Associate works on own schedule with minimal supervision – Associate has own malpractice insurance

Financial control factors that suggest EMPLOYEE: – Practice pays a salary or hourly rate – Practice reimburses business expenses – Practice provides benefits (health insurance, retirement) – Associate has no economic risk of loss

Financial control factors that suggest CONTRACTOR: – Associate is paid a percentage of collections (production split) – Associate has unreimbursed business expenses (CE, licenses, malpractice) – Associate has potential for profit and loss – Associate works for multiple practices

Type of relationship factors that suggest EMPLOYEE: – Long-term relationship – Written employment agreement – Associate provides services that are integral to the practice – No defined end date

Type of relationship factors that suggest CONTRACTOR: – Defined project or term – Written independent contractor agreement – Associate provides services that are auxiliary to the practice

Most associate dentist arrangements lean toward EMPLOYEE classification. The associate works in the practice’s facility, uses the practice’s equipment and staff, follows the practice’s protocols, and provides services that are integral to the practice. Even with a written contractor agreement and percentage-of-collections compensation, the substance often points to employee.

The risk of misclassification. If the IRS or state determines the associate is an employee but you classified as contractor: – Back taxes for failure to withhold income tax – Back FICA and Medicare (both employer and employee shares) – Federal unemployment tax (FUTA) – State unemployment tax – Penalties under IRC §6651, §6656, and others – Interest on all of the above For a 2-year period of misclassified associate compensation of $250K/year, the back taxes and penalties can hit $50K-$80K. Plus the cost of going back and correcting payroll records.

Safe harbor. Section 530 of the Revenue Act of 1978 provides safe harbor relief from worker classification challenges if: – The practice consistently treated the worker as a contractor – The practice filed all required 1099s – The practice had a reasonable basis for the classification (industry practice, prior IRS audit acceptance, judicial precedent, etc.) Many dental practices that have historically used contractor arrangements have §530 protection. But you can’t rely on it for new arrangements without a documented reasonable basis.

Practical classifications.

Pattern 1: Full-time associate dentist who works only at one practice, follows practice protocols, uses practice equipment. Employee. W-2. Pattern 2: Part-time associate dentist who works 2 days/week at your practice and 2 days/week at another practice, sets own schedule, brings own malpractice insurance. Possibly contractor (1099) under §530. Pattern 3: Locum tenens dentist filling in for vacation, has own malpractice, works at multiple practices. Generally contractor. Pattern 4: New graduate associate transitioning to ownership through buy-in. Employee. W-2.

Pattern 5: Specialist who comes in once a week to do specific procedures (e.g., orthodontist or oral surgeon at a general practice). Possibly contractor depending on autonomy.

Voluntary Classification Settlement Program (VCSP). The IRS offers VCSP for employers who want to voluntarily reclassify workers from contractor to employee. The VCSP provides reduced penalty exposure for past classifications in exchange for going-forward W-2 treatment. Form 8952 is the application.

The Reed Corporation regularly advises dental practices on associate classification. Many practices are 6-12 months into a contractor arrangement that should have been W-2 from the start. Fix it before the IRS or state finds it. Reclassify going forward; document the reasonable basis for the prior classification; and consider VCSP if exposure is significant.

Cash balance plus 401(k) profit-sharing stack for dental practices

Same concept as for physicians but with dental-specific wrinkles. A solo dental practice with the dentist as sole employee can fund a massive defined benefit pension. A practice with staff (hygienists, dental assistants, front desk) must include the staff in the plan — increasing cost but still typically worthwhile.

Solo practice (dentist + spouse on payroll, no other employees). Cash balance plan plus 401(k) profit-sharing stack functions identically to the physician case: – 401(k) employee deferral: $23,500 (2025) – 401(k) employer profit-sharing: up to $46,500 (to reach $70K 415(c) limit) – Cash balance plan contribution: actuarially determined, $100K-$400K depending on age – Total: $170K-$470K of pre-tax contributions annually For a 50-year-old dentist with sufficient income: $200K-$300K combined.

Practice with W-2 staff. The cash balance plan must satisfy IRC §401(a)(26) coverage and non-discrimination rules. The plan must cover at least 40% of employees (or 2 employees, minimum). Staff must receive a meaningful benefit.

Typical structure: cross-tested plan where the dentist receives a large pay credit (say, 25% of compensation) and staff receive a smaller credit (3-5% of compensation). The actuarial structure must satisfy non-discrimination testing under IRC §401(a)(4).

Example. Dentist owner with $250K W-2. 5 staff members averaging $50K W-2 = $250K total staff payroll. Cross-tested plan: dentist gets 25% pay credit ($62,500); staff get 5% pay credit ($12,500 across all staff). Plus 401(k) profit-sharing of 7.5% for staff and effectively the rest of the $46.5K limit for the dentist. Dentist’s total benefit: $62,500 cash balance + $46,500 401(k) profit-sharing + $23,500 deferral = $132,500 pre-tax. Staff cost: $12,500 cash balance + ~$18,750 (7.5% of $250K staff payroll) 401(k) profit-sharing = $31,250. Net to dentist after staff cost: $132,500 – $31,250 = $101,250 of effective tax-advantaged contribution at a cost of $31,250 of staff benefits.

The staff cost is a real economic cost (you’re putting money into staff retirement accounts). But it builds loyalty, reduces turnover, and is deductible to the S-corp. Net of the deduction, the staff cost at a 40% combined marginal is effectively $18,750 — and the dentist’s tax benefit on $132,500 of contributions at 45% combined is $59,625. Net positive.

Plan administration costs. Cash balance plans require actuary, third-party administrator, recordkeeper, and ERISA compliance. Annual costs typically: – Solo plan: $4,000-$6,000 – Plan with 5-10 employees: $7,000-$12,000 – Plan with 15-25 employees: $10,000-$20,000 Administrative fees are themselves a deductible business expense.

Coordination with the dentist’s W-2. The cash balance plan benefit is tied to W-2 compensation. The 401(k) profit-sharing is tied to W-2 compensation. So the dentist’s W-2 needs to be high enough to support the plan benefits. For a 50-year-old dentist targeting $300K of cash balance contribution, W-2 of $300K-$350K is typically sufficient (the plan formula and actuarial design determines the exact relationship).

This affects the reasonable comp / K-1 split. Higher W-2 supports larger retirement contributions. But higher W-2 also means more FICA. Optimal balance: W-2 high enough to fund the retirement plans, with the rest as K-1 distribution.

Funding flexibility. Cash balance plans have minimum funding requirements under IRC §430. Once you set up the plan with a target benefit, you must fund at least the minimum each year. Bad years are a problem. Mitigation: design conservative target contributions. Use plan amendments to adjust target benefits if income changes. Maintain a cash reserve in the practice to fund minimum contributions in down years.

Exit at retirement. Cash balance balance rolls to IRA at retirement. Lifetime tax-deferred growth. Subject to RMDs at age 73 under SECURE 2.0. Plan Roth conversions during low-income early-retirement years.

Sale of practice. Cash balance plans typically continue to exist when a dentist sells the practice. The buyer can take over plan sponsorship or the seller can freeze and terminate the plan. Plan termination requires PBGC notice and final distributions. Get an ERISA attorney involved.

Multi-location practices and the management LLC structure

Dentists who own multiple practice locations face additional structuring decisions. Common patterns:

Pattern A: Single S-corp owns all locations. Each location is a branch of the same S-corp. Simple but limited flexibility for partner / associate buy-in arrangements at individual locations.

Pattern B: Separate S-corp for each location. Each location is its own legal entity. More complexity but allows different ownership structures at each location. Partners or associates can buy into a specific location without buying into all locations.

Pattern C: Holding S-corp owns subsidiary LLCs for each location. The subsidiaries are disregarded entities flowing up to the S-corp. Allows asset protection separation (a malpractice claim against location A is contained at location A) while keeping tax simplicity.

Pattern D: Management S-corp plus separate practice entities. Each practice is a separate PC or PLLC (sometimes required by state law for professional services). The management S-corp provides admin, billing, marketing, and equipment leasing to the practices. The practices pay management fees to the management entity. This structure is common in dental support organizations (DSOs) and emerging in private practice. Used carefully, it can isolate non-SSTB management activities for §199A purposes — though the IRS scrutinizes management fee arrangements.

Choosing the right structure depends on: – State law on professional practice ownership (some states require PC/PLLC for dental practice) – Number of locations and growth plans – Partner / associate buy-in expectations – Asset protection priorities – Tax efficiency goals

For a solo dentist with 1-2 locations, Pattern A (single S-corp) is usually fine. For a growing practice with 3+ locations and ambitions for more, Patterns B or C provide more flexibility.

Tax implications of multi-location structures. State taxation. Multi-state practices must file state returns in each state where they have nexus. Apportionment rules vary. Often allocation by sales/receipts, payroll, and property factors. Federal §199A treatment. Each separate trade or business is analyzed separately for §199A. The dentist may have multiple QBI activities to aggregate or report separately. Aggregation rules under Treas. Reg. §1.199A-4 allow related trades or businesses to be aggregated, simplifying the limitation calculations. For most dental practices that are all SSTB, aggregation vs. separate doesn’t matter — the income is all phased out above the threshold either way. Real estate at multiple locations. Separate LLCs for each property, leased back to the operating entities. Provides asset protection and §199A planning for the rental income (subject to the SSTB self-rental treatment).

DSO arrangements. Dental Support Organizations (DSOs) provide centralized non-clinical services (billing, marketing, HR, IT, real estate) to multiple dental practices. The DSO is generally a separate company that contracts with the dental practices. DSO ownership structures vary: – Dentist-owned DSO providing services only to dentist-affiliated practices (private practice DSO) – Private equity-owned DSO acquiring and managing dental practices (corporate DSO) Tax treatment depends on the specific structure. For dentist-owned DSOs, the management entity can be non-SSTB if it provides genuinely non-clinical services (administration, billing, equipment leasing, real estate management). The dental practice entities remain SSTB but the management entity income may qualify for §199A. IRS scrutiny is high. The management fees must be arm’s-length and reflect actual services. The management entity must have economic substance. Document carefully.

Multi-state expansion considerations. Adding a location in another state triggers state nexus, state income tax, state sales tax (if applicable to dental services in that state), and state professional licensing. The dentist personally must be licensed in the state where services are performed. For SSTB dental practice income, state §199A treatment varies by state conformity. Some states conform to federal §199A (rare), some don’t conform at all, some have different state-level pass-through deductions.

Partnership taxation considerations. If the multi-location structure involves multiple owners (you plus an associate or partner), the LLC may be taxed as a partnership (filing Form 1065 with K-1s to partners) or as an S-corp. Partnership taxation offers more flexibility for allocations and special distributions but doesn’t provide the SE tax savings of S-corp on the K-1 portion. For dentist-owned multi-location practices with multiple partners, S-corp is still typically preferred.

Common dentist tax mistakes — and what they cost

Recurring errors I see in dentist tax returns when they cross our desk for the first time. Each one costs $5K-$50K per year if uncorrected.

Mistake 1: Paying below-market W-2 salary to make the most of K-1 distributions. Dentist owner of an S-corp pays himself $80K W-2 on $400K of net practice income. IRS challenge upon audit reallocates $120K from K-1 to W-2, assesses back FICA, penalties, and interest. Cost: $25K-$50K plus the IRS scrutiny. Fix: pay yourself BLS / ADA benchmark for your specialty. Document the comp study.

Mistake 2: Missing the §199A deduction on non-SSTB income. Dentist owns the office building separately. Building rental income could qualify for §199A if structured properly. Many dentists fail to elect or compute the deduction. Cost: $4K-$8K per year on a typical building. Fix: get the building into a properly structured rental real estate trade or business; claim §199A on Form 8995-A.

Mistake 3: Ignoring the §269A C-corp trap. Dentist forms a C-corp expecting the 21% rate to be a tax shield. Double tax on dividends destroys the benefit. Cost: $20K-$80K per year. Fix: elect S-corp status. File Form 2553 with late election relief if needed.

Mistake 4: Missing accountable plan reimbursements. Dentist pays $15K of CE, home office, vehicle, and professional dues out of pocket. Post-TCJA, no Schedule A deduction. Pre-tax reimbursement through accountable plan would save $6K-$7K annually. Cost: $6K-$10K per year. Fix: adopt written accountable plan; substantiate and reimburse routinely.

Mistake 5: Failing to make timely §179 elections or coordinate bonus depreciation. Dentist buys $200K of equipment but takes only MACRS depreciation. Slow recovery. Higher current-year tax. Cost: $15K-$30K of timing differences (eventually recovered through smaller future depreciation but lost time value of money). Fix: §179 plus bonus depreciation election on Form 4562 in the year placed in service.

Mistake 6: Misclassifying associate dentist as 1099 when they should be W-2. Cost of misclassification: $15K-$60K per year per misclassified associate in back taxes, penalties, interest if audited. Fix: analyze classification carefully. When in doubt, W-2. Use the VCSP to reclassify going forward with reduced penalty exposure.

Mistake 7: Skipping the cash balance plan. Dentist with $400K+ of net income contributes only to a 401(k) ($23.5K deferral + $46.5K profit-sharing = $70K). Could be funding another $100K-$250K through a cash balance plan. Cost: $40K-$100K of annual tax savings forgone. Fix: set up cash balance plan with TPA / actuary. Coordinate with 401(k).

Mistake 8: Maxing all retirement contributions to pre-tax 401(k) when Roth would be better. Dentist in 32% bracket prepays nothing through Roth; pulls out money in retirement at 35% bracket (post-TCJA reversion + state). Cost: 3-5% rate arbitrage on the contributions, compounded over 20-30 years. Fix: model bracket arbitrage. Consider Roth contributions or in-plan Roth conversions for at least part of the contribution.

Mistake 9: Not claiming the §199A deduction during low-income years (sabbatical, parental leave, ramp-up year). Dentist in year of practice acquisition has low taxable income — below the SSTB threshold. §199A deduction available on practice QBI. Often missed. Fix: review eligibility annually. Compute Form 8995 if income is below threshold.

Mistake 10: Failing to use the PTET election for state SALT cap workaround. High-income dentist in California with $30K of state tax. Personal SALT capped at $10K. Could elect PTET to deduct the additional state tax at the entity level — federal tax savings of $7K-$8K per year. Cost: $7K-$10K per year. Fix: elect PTET in the state where the S-corp operates.

Mistake 11: Missing the HSA contribution. Dentist has hospital-quality HDHP through state-marketplace coverage but doesn’t fund the HSA. Cost: $3K-$4K of tax savings per year. Fix: fund the HSA up to the family limit. Invest the balance for long-term growth.

Mistake 12: Insufficient documentation supporting deductions. Dentist takes a $30K home office and vehicle deduction with no log, no receipts, no allocation methodology. IRS audit disallows most of it. Cost: $5K-$15K plus penalties. Fix: keep documentation. Mileage log, receipts, contemporaneous notes. Use practice management software for record-keeping.

Mistake 13: Not considering ESOP for exit planning. Older dentist looking to exit the practice. Sale to another dentist or DSO triggers capital gains. ESOP allows tax-deferred sale of practice equity to an employee stock ownership plan with significant tax benefits under IRC §1042. Fix: consider ESOP for practices with $1M+ of value and at least a few years of operations remaining. Get specialized advisor.

These mistakes are routine. Most dentists I work with for the first time have at least 3-5 of them in place. Fixing them recovers $30K-$80K of annual tax savings, often more for larger practices.

Putting it together — a complete dentist S-corp tax stack

Let me show what a tight dentist S-corp tax planning stack looks like in practice. Meet Dr. Patel, a 48-year-old general dentist who owns a single-location practice in Texas (no state income tax — simplifies the math).

Practice baseline. Gross collections $1.2M. Practice expenses (staff, supplies, lab fees, rent, utilities): $700K. Net practice income before owner comp and retirement contributions: $500K. Married filing jointly with a spouse working part-time at $40K W-2 elsewhere. Two kids in private school.

Pre-planning baseline (sole prop or single-member LLC): $500K net to dentist. Federal tax at marginal rates roughly $145K. FICA self-employment $30K. NIIT $5K. Total tax: $180K. Effective rate on practice income: 36%.

The stack:

Step 1: S-corp election. File Form 2553. Restructure as Dr. Patel DDS, PA elected as S-corp. Pay reasonable comp $200K W-2 (BLS median range for general dentist in Texas). $300K K-1 distribution. SE tax savings on the $300K K-1 portion: $300K × 2.9% Medicare = $8,700 saved. Plus additional Medicare 0.9% on income over $250K MFJ: $300K × 0.9% × portion above threshold = $1,500. Total payroll tax savings: ~$10,000 annually.

Step 2: Solo 401(k) plus cash balance plan. The S-corp sponsors both. – Solo 401(k) employee deferral from W-2: $23,500 – Solo 401(k) employer profit-sharing: $46,500 (to reach $70K 415(c) limit at age 48) – Cash balance plan: $160K (designed by actuary for 48-year-old) – Total pre-tax retirement contributions: $230,000 Tax savings at 32% federal marginal: $73,600 annual savings. The $230K is contributed by the S-corp ($206.5K of employer contributions reducing S-corp net income) plus $23.5K reducing Dr. Patel’s W-2 box 1.

Step 3: Accountable plan. Dr. Patel’s S-corp adopts a written accountable plan. Reimburses: – Home office: $3,000 – Vehicle (75% business use of a Tahoe over 6,000 lbs): $8,000 – CE/conferences: $7,000 – Professional dues: $2,500 – Phone/internet (60% business): $1,500 – Misc business expenses: $2,000 – Total: $24,000 All reimbursed pre-tax through the S-corp. Tax savings at 32% combined (no state income tax in Texas): $7,680 annual savings.

Step 4: Section 179 / bonus depreciation on equipment. Practice buys $100K of new equipment in the year (cone-beam CT upgrade plus CAD-CAM mill). Full §179 election. $100K immediate deduction. Tax savings at 32% federal: $32,000 in the year (timing-related, not permanent — recovered over normal depreciation period otherwise).

Step 5: HSA. Family HDHP through Dr. Patel’s hospital affiliate plan. Annual HSA contribution: $8,550 (2025; projected $8,750 for 2026). Tax savings at 32%: $2,736.

Step 6: Backdoor Roth for both spouses. $7,000 × 2 = $14,000 to Roth annually. No current-year deduction; long-term tax-free growth.

Step 7: §529 for kids. Texas doesn’t have a state tax deduction for §529, but federal tax-free growth is valuable. Annual contributions: $19,000 per kid × 2 = $38,000. No current-year tax savings but compounding for future education costs.

Step 8: Charitable bunching. Dr. Patel’s family gives $10,000 annually to church and local charities. Bunching 3 years into a DAF: $30,000 contribution in year 1. Itemized vs. standard ($30K + $10K SALT = $40K vs $30,200 standard): only marginal $9,800 deduction benefit. At 32% federal: $3,136 of additional tax savings versus standard deduction. Use appreciated stock if available — donate Apple shares held >1 year worth $30K with $15K cost basis. Avoid $15K of unrealized capital gain (~$2,250 in saved capital gains tax). Total charitable bunching benefit: $5,386.

Step 9: PTET election (not applicable in Texas — no state income tax). For dentists in states with income tax, the PTET election adds $5K-$15K annual savings.

Step 10: Real estate. Dr. Patel owns the dental office building through a separate LLC. The LLC rents to the dental S-corp at $80K/year (arm’s-length market rent). The LLC has $20K/year of expenses (property tax, insurance, repairs). Net rental income: $60K. Depreciation on the building ($1M basis, 39-year MACRS): $25,600/year. After depreciation: $34,400 taxable rental income. The rental income is subject to §199A SSTB self-rental rules (treated as related to the SSTB practice, phased out above threshold). So no §199A on the rental. But the $25,600 depreciation reduces taxable rental income. And eventually the building has potential for cost segregation studies to accelerate depreciation on personal property components.

Step 11: Beneficiary designations and estate planning. Update all retirement accounts (401(k), IRA, cash balance, Roth) to name spouse as primary and children’s trust as contingent. Coordinate with overall estate plan.

Total annual tax savings from the stack: – SE tax savings from S-corp: $10,000 – Retirement contribution deductions: $73,600 – Accountable plan: $7,680 – §179 equipment: $32,000 (timing) – HSA: $2,736 – Charitable bunching: $5,386 – Total annual savings: $131,402

Effective rate goes from 36% on practice income to approximately 18%. Eighteen percentage points back to Dr. Patel’s family.

Over 20 years of running this stack, compounding the savings at 7%, the additional wealth is $5.5M-$7M. That’s the gap between a tightly planned dental practice and a poorly planned one. Same revenue, same patients, same dentist — different tax position.

For dentist S-corp tax planning, the architecture is repeatable. We run a version of this stack for 80% of the dentists we serve at The Reed Corporation tax strategy consulting. Specific numbers shift by practice size, specialty, state, and age, but the framework holds.