For most dentists, the decade before retirement is the window where Roth conversion strategy actually matters. Your income is at its peak, your practice may be approaching a sale, and the decisions you make now about where your retirement assets sit (taxable versus tax-free) will shape your tax bill for the next 20 to 30 years.
A Roth conversion means moving money from a traditional IRA or pre-tax retirement account into a Roth IRA. You pay ordinary income tax on the converted amount in the year of conversion. In exchange, that money grows tax-free and comes out tax-free in retirement, with no required minimum distributions (RMDs) during your lifetime.
What makes Roth conversions worth a serious look for dentists is the income profile. Practice owners often carry high pre-tax retirement balances built through defined benefit (DB) plans and 401(k)s, plus a potential practice sale that could create a one-time income spike. All of that creates both urgency and opportunity, and understanding why starts with the RMD problem.
Why Roth accounts matter more as a dentist approaches retirement
A dentist with a large traditional 401(k) or DB plan balance has a significant amount of pre-tax money, which means the IRS has a claim on every dollar when it comes out. At age 73, required minimum distributions begin, forcing annual taxable withdrawals whether you need the cash or not. For a dentist who also receives Social Security or income from a retained practice interest, those RMDs can push a significant portion of retirement income into higher brackets.
Roth IRAs have no RMDs during the original owner’s lifetime. Qualified Roth withdrawals are completely tax-free, which means they don’t count as income for calculating Medicare premium surcharges (called IRMAA, or Income-Related Monthly Adjustment Amount). For dentists retiring with high asset levels, keeping taxable income low in retirement can be as valuable as the tax rate on the conversion itself.
The RMD rules also shifted under the SECURE 2.0 Act of 2022, which raised the RMD starting age from 72 to 73 (and to 75 for those born in 1960 or later) — the original SECURE Act of 2019 had already moved it from 70½ to 72. That extra runway gives dentists more years to convert before the forced-distribution clock starts. Knowing when to act within that window is where the conversion strategy gets specific.
The best window for a Roth conversion as a dental practice owner
The conversion window that works best for most dentists is the gap between practice sale and age 73. If you sell your practice at 60 and retire at 62, you may have 10 or more years before RMDs begin where your ordinary income is lower than it was during your working years. That low-income bridge is the ideal time to convert pre-tax balances at the lowest possible rate.
The key metric is your marginal tax bracket. The goal is to convert enough each year to fill up available space in your current bracket without crossing into the next one. For 2026, the IRS has published updated tax brackets you can verify directly at IRS.gov; work with your advisor each year to identify exactly where your bracket ceiling sits before sizing a conversion.
What complicates this for dentists is the practice sale itself. An asset sale often generates a large taxable gain: a mix of ordinary income (equipment, non-compete agreements) and capital gains (goodwill). In the year of the sale, your income will likely spike, so plan conversions in the years before and the years after, once income normalizes.
Once you understand the timing window, the next question is how much to move each year, and three variables drive that answer.
How much to convert each year and how to decide
For most dentists, the strongest starting framework is a bracket-filling approach: convert enough each year to use up the remaining space in your current tax bracket without crossing into the next one. This requires knowing your projected taxable income with reasonable precision, which means your books need to be current and your estimated tax payments need to reflect real numbers.
A second consideration is state income tax. If you’re planning to relocate to a lower-tax or no-income-tax state in retirement, converting before the move means paying your current state’s rate on the converted amount. For dentists in high-tax states, this timing question alone can meaningfully change the math.
A third variable is investment performance. Converting during a market downturn, when the account value is temporarily lower, means you pay tax on fewer dollars and move more shares to Roth status. This is an opportunistic approach, not a substitute for the bracket analysis, and no one can reliably time markets — but it’s worth considering when markets have already pulled back significantly.
These three variables interact differently depending on whether you also carry a defined benefit plan, which is the case for many dentists who have been in practice for 20-plus years.
What happens to Roth conversions if you have a defined benefit plan
Many dental practice owners have a defined benefit plan or cash balance plan alongside a 401(k). These plans can accumulate very large pre-tax balances over a career, creating a significant RMD liability down the road. The IRS does not allow you to convert DB plan assets directly to a Roth while the plan is still active. Once you retire and roll the DB plan lump sum to a traditional IRA, those assets become eligible for conversion.
This is a planning pivot point that often gets missed. The year you terminate the DB plan and take a lump-sum rollover to a traditional IRA is not itself a taxable event when rolled over properly, but it’s often a year with plenty of moving parts. Any Roth conversion layered on top of that rollover can push your rate significantly higher, so the better approach is usually to let the rollover land first and then begin systematic conversions in subsequent years.
Cash balance plan annual contribution limits are set by the IRS each year based on age and actuarial assumptions, meaning a dentist in their late 50s can potentially contribute a substantial amount annually. That growing pre-tax balance increases the eventual Roth conversion opportunity, and it also adds to the Medicare premium exposure that comes with larger conversion amounts.
Does a Roth conversion affect Medicare premiums for dentists?
Yes, it can. Medicare Part B and Part D premiums are subject to IRMAA surcharges when your modified adjusted gross income (MAGI) exceeds certain thresholds. For 2026, the income thresholds and surcharge amounts are published by Medicare and change annually; at higher income levels, the surcharge can add hundreds of dollars per month per person to your premiums.
A large Roth conversion in a single year can push your MAGI above an IRMAA threshold and trigger premium increases for the following year. Because Medicare uses income from two years prior to calculate the surcharge, careful multi-year planning is required. Spreading conversions across several years rather than doing one large conversion tends to produce a better overall outcome.
Roth conversions are not the only retirement tax tool available to dentists, and they tend to work best when layered alongside a few complementary strategies.
Roth conversions versus other tax strategies near retirement
Roth conversions work best in combination with other moves: maximizing deductible retirement plan contributions in high-income working years, timing the practice sale to align with lower-income years, harvesting investment losses to offset conversion income, and planning charitable giving through a donor-advised fund or qualified charitable distribution (QCD), which becomes available at age 70½ — before RMDs begin.
The interaction between these strategies is where the integrated advisory model makes the most difference. A CPA who isn’t talking to your financial advisor may optimize your current-year return without considering the long-term Roth conversion strategy. A financial advisor who isn’t seeing your practice’s financials may miss that a large equipment purchase changes your conversion math for the year.
For dentists who want to explore whether their retirement account structure is positioned for the most efficient long-term tax outcome, our retirement planning for dentists team works through exactly this kind of multi-year projection.
When a Roth conversion is the wrong move for a dentist
Roth conversions don’t make sense in every situation. If your current marginal rate is higher than your expected retirement rate (common for dentists still running a busy practice), paying tax now to save tax later may not pencil out. If you need the funds for living expenses within a few years of conversion, the tax cost may not be recovered before withdrawals begin. And if your estate plan leaves retirement accounts to charity, those assets pass income-tax-free to a 501(c)(3) anyway, making conversion unnecessary.
The break-even horizon for a Roth conversion is usually measured in years — often a decade or more — depending on the rate differential and investment return assumptions. Dentists who are already in their late 60s and planning to spend down their portfolio may find the math doesn’t favor conversion. The strategy pays off most clearly when there’s a long horizon for the Roth assets to compound tax-free.
If you’re unsure whether a conversion fits your situation, our tax planning for dentists team can run a multi-year projection that models both paths so the comparison is concrete rather than theoretical.
Building a retirement income strategy around tax diversification
The goal of a Roth conversion strategy isn’t just to reduce the tax bill in any single year. It’s to build a retirement portfolio that gives you flexibility in how you draw income. A dentist with assets spread across taxable brokerage accounts, traditional pre-tax retirement accounts, and a Roth IRA can manage taxable income year by year, pulling from whichever bucket keeps them in the most favorable position.
This kind of tax diversification is genuinely difficult to achieve when advisors are siloed. The Roth conversion decision is connected to your practice sale timing, your expected Social Security filing age, your estate goals, and your Medicare premium exposure. These are not separate conversations. They’re one conversation with a team that sees all of it.
If you’re within 10 years of retirement and haven’t run a Roth conversion analysis alongside your retirement projections, that’s worth addressing now. The window for the most impactful conversions closes faster than most dentists expect. Reach out to the Core Advisors team to start a conversation about your retirement income strategy.
This article is for educational purposes only and is not tax, legal, or investment advice. Roth conversion outcomes depend on individual circumstances and future tax rates, which cannot be guaranteed. Consult your own tax or financial advisor about your specific situation.
