The chair-hour is the unit of production

Small teams don't have time to stitch together five tools and hope it works.

Apollo gives you everything you need to find leads, reach them, and close deals — all in one place:

Stop juggling tools and start building pipeline that scales.

With Apollo, the AI revenue engine powering 4M+ users.

Sign up for free

Four Sundays of quiet. My fault — I was building instead of writing. And I still owe you the annual-maximum story I teased last issue; it's coming, it just wouldn't fit here. From today the Ledger runs a fixed shape every Sunday: The Books, the Tiny DSO Diaries, and Bench Test.

Last issue argued that payer mix, not production, is the real P&L. This issue goes one level deeper. Ask a first-principles question: what does a dental practice actually sell?

Not crowns. Not prophys. You sell chair-hours: a fixed daily inventory of clinical time that expires, unsold, every night at close. Procedures are just the price a chair-hour clears at. Structurally you're running an airline, not a store — high fixed costs, perishable seats, and a P&L that reduces to price per chair-hour × utilization. Payer mix sets the price. The schedule sets the quantity. Everything else is commentary.

The industry instead manages a ratio: overhead as a percent of collections. The current reference bands:

Useful, but a percentage is a ratio of two flows, and it hides the mechanism. Break it apart: staff (25–28%), facility (7–10%), admin (4–6%), equipment (3–5%), insurance (2–3%) are all fixed in time, not in production. Call it 45% of collections that goes out the door whether or not anyone is in the chair. Only supplies and lab (each ~5–8%) actually ride with volume.

Now put it in the right unit. Take a practice collecting $1.2M across ~3,500 delivered chair-hours: about $343 per chair-hour coming in. The fixed base — $1.2M × 45% ≈ $540K — burns about $154 every chair-hour, occupied or not. Your P&L never prints that number, and it's the one that runs your year. A cancellation isn't "lost production." It's inventory spoiling at $154 an hour while the meter keeps running. It's also why the marginal patient is worth far more than the average one.

Hygiene is where you see this most cleanly. The reference bands: $1,200–$1,600 per hygienist-day in PPO practices, $2,000+ fee-for-service, a production-to-wage floor of 3:1 and healthy at 3.5:1, with hygiene carrying ~25% of practice production (30–33% in strong departments). Every one of those is secretly a chair-hour statement. A $1,400 day over 8 hours is a $175/hour department sitting on a ~$154/hour fixed burn. The margin is utilization. It was never heroics.

The Operator Tactic: pull last month's collections and your delivered clinical hours — delivered, not scheduled. Divide. That's your price per chair-hour. Apply the fixed-cost split above and you have your empty-chair burn. Two numbers, ten minutes, and they'll predict your year better than any overhead percentage will.

Who says the big boys get to have all the fun? This is my build log. I'm assembling a micro-network of practices and printing the numbers here weekly — wins and stalls both, starting embarrassingly small on purpose. The bet: the chairside recommendation is the cheapest trust gradient in healthcare, and a small network that measures itself honestly will compound past a big one that doesn't.

The honest read this week: two clinics, each moving about a box a month of a rinse we dispense chairside, both reordering without being chased. That's the entire empire right now. But those are the only three numbers that matter at this stage — count, velocity, repeat. If the reorder rate holds while the count grows, the model's real. If it breaks, you'll read that here too.

Dental AI is sold on demo-day adrenaline. Starting next issue, Bench Test grades these products the way an owner should underwrite them — one product per issue, same five lines every time:

One standing law: vendor money never touches a review. No sponsored verdicts, no affiliate strings on anything we grade. A scorecard is only worth reading if it can't be bought.

Have a product you want on the bench first? Reply to this email. I'm building the queue now.

Benchmark bands above draw on ADA Health Policy Institute practice-economics reporting and Dental Economics survey data as compiled in current industry references (overhead, hygiene production); treat them as reference bands, not gospel. Worked examples are illustrative.

Next Sunday: the first Bench Test verdict — and the annual-maximum story is still in the queue, I promise. Bring your chair-hour number.

— Thad

The Practice Ledger is a neutral data publication. Nobody buys a number: sponsors buy adjacency, never editorial. Sources and methodology for every benchmark we publish are available on request.