This week a Substack essay titled “Do dentists actually know what they’re doing?” climbed the front page of Hacker News, where it has since collected 892 points and 638 comments. The piece is a reconstructed dialogue between a patient and two dentists — one who wants to drill, one who says, in effect, that if it were his own kid he wouldn’t be drilling anything yet. The comment section reached its verdict fast: somebody here is selling something.

That is the least interesting conclusion available. The headline isn’t really asking whether dentists are competent or crooked. It’s asking whether anyone can tell. And the answer — the one the thread kept circling without landing on — is no. Not you. Not the insurer. Not the second-opinion dentist. Not the dentist holding the drill, either.

The Only Outcome Measure Is Silence

Every other branch of medicine has a grading system bolted to it. Cardiology has readmission rates. Oncology has staging and five-year survival. Surgery has a pathology report on whatever got cut out. Dentistry’s outcome measure is that you stopped mentioning it.

A filling that was unnecessary and a filling that saved a tooth look identical from the chair five years later. The tooth is quiet either way. The cavity “caught early” that would never have progressed is indistinguishable from the cavity that would have abscessed by spring, because the drill erases the evidence. There is no pathology report for a crown.

This is not a conspiracy. It’s a measurement vacuum — which is why the debate always collapses into dueling anecdotes. On the Skeptical Cardiologist’s Substack, where a periodontist has weighed in on the original essay, readers traded the same story in the comments: cancel the follow-up, get the x-rays taken at next year’s cleaning, hear nothing more about that cavity. Some of those readers were probably right. Some were probably lucky. Nobody will ever know which, including them.

And when an information vacuum opens, a market fills it with something else. As one equipment rep put it at a regional dental convention this fall, standing beside a machine with a financing sticker still on the housing: “Nobody buys the drill because it’s better. They buy it because the guy in their study group bought it.”

The ADA’s Dashboard Measures Mood, Not Results

The profession’s own research arm is not hiding anything; it simply has nothing to measure. The American Dental Association’s Health Policy Institute publishes a “State of the U.S. Dental Economy: Q3 2026 update,” and its market work tracks utilization, expenditures, and dentists’ economic confidence. It is real, careful work. It is also a dashboard for how dentists feel about their businesses, not whether their work worked.

The research follows the same contour. “Financial Incisors: Cutting Through the Effects of Private Equity on Dentistry Market Dynamics and Care Delivery,” published in Health Services Research in December 2025, set out to assess how private-equity ownership affects prices, service mix, and Medicaid participation at the practice level. Prices. Service mix. Participation. Every variable anyone can observe — because outcomes are the one thing the data cannot see.

Here is where my own side should start squirming. The standard answer to provider misconduct is competition: give patients choice, transparency, star ratings, let the bad actors get sorted out. But consumer discipline requires the consumer to observe quality, and dentistry is engineered so they cannot. A five-star review measures parking and whether the hygienist was nice. It tells you nothing about whether the molar needed work. Markets discipline firms that produce feedback. This one produces none, so the sorting happens on price and vibes, which is exactly how you end up with private equity buying up practices and a viral essay asking whether anyone in the room knows anything.

Self-Governance Has the Same Blind Spot

The reflex on the other side is that a regulator should fix this. State dental boards are, by design, mostly dentists — the profession grading itself. In June 2025, North Carolina Health News reported that lawmakers there were weighing changes to how the N.C. Board of Dental Examiners is selected, alongside Medicaid reimbursement rates and whether to let private equity further into the practice of dentistry. Three fights, one blind spot: not one of them generates the missing data.

With outcome data, the private-equity question would be easy to settle. Does the corporate-owned practice drill more teeth per patient than the solo dentist down the road? Does the tooth survive? Absent that, the argument is about ownership structures and atmospherics, and the board — staffed by the very people whose work is being assessed — has no evidentiary basis to say anything firm. Neither would a consumer-protection bureau.

What Fixing This Would Actually Require

The boring answer is a registry. Anonymized claims data already exists in insurers’ systems; it knows which tooth got filled and which tooth needed a root canal fourteen months later. A longitudinal national record of re-treatment rates would not tell you whether any individual filling was justified. It would tell you which practices sit three standard deviations above their peers, and whether the pattern holds after you adjust for case mix. A dentist with a high re-treatment rate isn’t necessarily a crook — maybe they take the hard cases. But you would know to look, which is more than anyone can do today.

The uncomfortable part is what measurement would do to everyone’s certainty. Some dentists would turn out better than their reputations. Some would turn out worse, and a few of the profession’s most confident voices would be revealed as guessing loudly. The one thing we would lose is the ability to argue about this forever without a single number — which, judging by 638 comments, is the thing the internet most wants to keep.

I’m not telling anyone to skip a filling. That is between you and your dentist, and I’m not qualified to have an opinion on your teeth. I’m saying the reason you can’t get a straight answer isn’t that dentists are ignorant or venal. It’s that the profession has spent a century building a business on work no one ever grades — and the bill for that, this week, arrived in the form of an essay title that half the internet found uncomfortably familiar.

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