Most dental practice owners find out about the Roth IRA income limit the hard way: they try to contribute and their financial software tells them they cannot. The IRS phases out direct Roth IRA contributions for single filers with modified adjusted gross income (MAGI) above $153,000 and eliminates them entirely above $168,000 for 2026. For married filers, the phase-out runs from $242,000 to $252,000. Most owner dentists clear these limits comfortably, which means they are blocked from one of the best tax-advantaged accounts in the tax code.
The backdoor Roth IRA is the legal mechanism that gets around this. It has been in use since 2010, when the income limit on Roth conversions was removed, and Congress acknowledged the strategy in the legislative history of the 2017 tax act. It remains available as of 2026. The name makes it sound like a workaround, but it is really just a two-step contribution process that anyone can use regardless of income.
The backdoor Roth IRA lets dentists contribute regardless of income
The process has two steps. First, contribute to a traditional IRA without claiming a deduction. There is no income limit on non-deductible traditional IRA contributions, only on deductible ones. Second, convert that traditional IRA balance to a Roth IRA. The conversion itself is not limited by income. What you convert is taxable to the extent it was pre-tax money, so if you hold no other pre-tax IRA money the conversion typically generates little or no additional tax. If you do hold pre-tax IRA money, the pro-rata rule below changes that answer significantly. The result, done cleanly: after-tax money now sits in a Roth account where it can grow tax-free and come out tax-free in retirement.
The contribution limit for an IRA in 2026 is $7,500 per person, or $8,600 if you are 50 or older, per the IRS. For a married couple where both spouses do a backdoor Roth, that is $15,000 to $17,200 per year going into tax-free growth. Over a 20-year career, even without investment returns, that is a meaningful pool of tax-free wealth.
What is the pro-rata rule and why does it matter for dentists?
The pro-rata rule is where the backdoor Roth gets complicated for dentists who have existing pre-tax IRA money — and dentists very often do. A rollover IRA holding a residency-era or associate-era 401(k), a SEP-IRA opened during 1099 associate years, a SIMPLE IRA from a first practice job, or a deductible traditional IRA contribution from earlier years all count. The IRS does not let you treat a conversion as if it came only from after-tax dollars when you have a mix. Instead, the taxable portion of any conversion is calculated on the ratio of pre-tax to after-tax money across ALL of your traditional, SEP, and SIMPLE IRAs combined, measured by their total balance on December 31 of the year you convert.
For example: if you have $90,000 in a rollover IRA (pre-tax) and you make a $7,500 non-deductible contribution for 2026, you now have $97,500 in traditional IRA assets with only about 7.7% in after-tax dollars. Converting $7,500 to Roth would make roughly $6,900 of it taxable (approximate, 2026). One important note: the rule is applied per person, not per household, so your spouse’s IRA balances do not contaminate your conversion. The workaround dentists most commonly use is rolling the pre-tax IRA balance into their practice’s 401(k) plan before doing the conversion, which removes the pre-tax money from the IRA pro-rata calculation entirely. This only works if the 401(k) plan accepts rollover contributions — and as the practice owner, you control that plan document, so it is usually a fixable problem rather than a dead end.
Backdoor Roth IRA pairs well with a dental practice 401(k)
The backdoor Roth works best as one piece of a broader retirement picture for dental practice owners. A well-structured practice 401(k) with profit sharing allows owner dentists to contribute up to $72,000 in 2026 (the Section 415 limit, combining employee deferral and employer profit sharing), subject to the $360,000 compensation limit — which is one more reason owner W-2 compensation gets set up toward that limit rather than down. The backdoor Roth then adds another $7,500 to $8,600 in tax-free growth on top. For dentists also running a cash balance defined benefit plan, the combined annual retirement contribution can exceed $200,000 depending on age and plan design. Our retirement planning for dentists team models these combinations regularly.
The tax-free growth inside a Roth account is also particularly valuable for dentists because practice income peaks during the ownership years, meaning you are in high brackets while contributing and can draw on the Roth later when your bracket is lower — or when you want flexibility to avoid pushing other income into a higher bracket. That flexibility matters most in the years around a practice sale or DSO transaction, when a large one-time gain can stack on top of ordinary income; Roth dollars are the ones you can pull without adding to that year’s taxable income. Tax diversification across pre-tax and Roth accounts gives you options in retirement that a purely pre-tax strategy does not.
How does the conversion get reported on a tax return?
The non-deductible contribution to the traditional IRA is reported on Form 8606, which tracks your after-tax IRA basis over time. The conversion from traditional to Roth is reported on Form 8606 as well. If the conversion is fully non-taxable (because you converted quickly after contributing, with no earnings, and no pre-tax IRA balances in the way), Form 8606 documents the zero-tax conversion. If there is a taxable portion due to the pro-rata rule, that amount shows up as ordinary income on your return for the year of conversion. File Form 8606 every year you make a non-deductible contribution — the basis it tracks is what keeps you from paying tax twice on the same dollars years later, and reconstructing a missing history is far harder than filing the form.
One timing note: converting shortly after making the non-deductible contribution minimizes the chance that investment gains accumulate inside the traditional IRA before conversion. Any earnings that do accrue are taxable at conversion, so the common practice is to convert promptly rather than waiting months.
Does the mega backdoor Roth work for dental practice owners?
The mega backdoor Roth is a separate strategy that involves making after-tax contributions to a 401(k) plan and then converting or rolling those after-tax amounts into a Roth account. It can allow considerably higher Roth contributions than the standard backdoor route — the after-tax room is whatever is left of the $72,000 Section 415 limit in 2026 after your own deferrals and any employer contributions, so it is at most $47,500 for those under 50 and usually less once profit sharing is funded. It works only if the 401(k) plan document explicitly allows after-tax contributions and in-service distributions or in-plan Roth conversions, and the plan must still pass nondiscrimination testing on those after-tax amounts. Most off-the-shelf 401(k) plans do not include these provisions by default. Owner-dentists who control their own plan design can often add these features, which is one reason why dental practice retirement plan design matters beyond just the contribution amount.
What dentists should do before attempting a backdoor Roth
Three things to confirm before starting the process: whether you have any pre-tax traditional, SEP, or SIMPLE IRA balances that could trigger the pro-rata rule, whether your practice 401(k) accepts rollovers if you need to clear those balances, and whether your IRA custodian handles the two-step contribution and conversion cleanly without creating unintended tax events. The mechanics are not difficult, but the sequencing matters — and because the pro-rata test looks at your December 31 balance, a rollover that clears the pre-tax money has to land before year-end, not merely before the conversion. A misstep on timing or a missed Form 8606 can create phantom taxable income that takes effort to unwind.
The backdoor Roth is rarely a standalone decision. Whether it makes sense depends on what your practice 401(k) and profit sharing are already absorbing, what your owner W-2 compensation is set at, and how close you are to a transition — the same inputs that drive plan design and exit planning. Core Advisors works with dental practice owners on retirement strategy that spans the practice and personal sides of their financial life, under one roof, so those pieces get decided together rather than in sequence. If you want to understand whether the backdoor Roth belongs in your plan alongside your practice retirement accounts, reach out to the Core Advisors team to talk through the full picture.
This article is for educational purposes only and does not constitute tax, legal, or investment advice. Figures cited are for the 2026 tax year unless noted, are approximate where labeled, and are subject to change. Consult your tax and financial advisor about your specific situation before acting on any strategy discussed here.
Related reading: Health Savings Accounts For Dentists: The Triple-Tax Advantage And How To Use It · Roth Conversion Strategies for Dentists Nearing Retirement
