Filling or crown? What separates them, and the size of the gap in money

A filling replaces part of a tooth. A crown replaces the outside of the whole tooth, after what remains has been cut down to take the cover. The difference between them is how much sound tooth is left to work with — and that is a judgement made by a dentist who has examined the tooth and seen the X-rays. Nothing on this page decides it, and nobody reading a website can.

What this page can do is show the size of the decision, because the published gap between the two is larger than almost anyone expects and it is not obvious from a quote.

The gap, on three published schedules

The multiples are arithmetic on the two figures beside them and nothing more. They vary between payers because the schedules grade fillings and crowns differently — Pennsylvania barely increases its filling fees with size, so its ratio blows out; Montana pays generously for large fillings, so its ratio is the tightest of the three. In every case the crown is several times the filling, and in every case the extra lines that come with a crown are on top.

That last point is easy to miss. A crown quote is rarely just the crown: building the tooth back up is allowed $158.08 in Montana and $200.00 in Washington as its own line, and a post and core is another. The crown types and cost page sets out every one of those.

What actually decides it

The ADA's own list of when a crown is used includes the case exactly: a large filling where "there isn't enough tooth remaining" to hold it, along with a broken tooth, a weak tooth needing protection, and covering a discoloured or misshapen one. That is the boundary in the plainest published form we found — at some point there is not enough tooth left for a filling to be held by, and a cover becomes the option instead.

Where exactly that point falls for your tooth is not something a page can establish, and a site that pretended otherwise would be doing something worse than useless. But it is a reasonable thing to ask a dentist directly — how much sound tooth is left, and what happens if a filling is placed instead — and to have the answer written on the plan.

Filling materials: what the ADA and the FDA publish

If a filling is the answer, the next question is usually what it is made of, and here there are genuinely authoritative sources rather than opinion.

The ADA describes composite resins — the tooth-coloured option — as offering "good durability and resistance to fracture in small- to mid-size fillings that need to withstand moderate pressure", usable on front or back teeth. It notes they "cost more than amalgam and occasionally are not covered by some insurance plans", take longer to place, and that some studies show they "can be less durable and need to be replaced more often than amalgam fillings". Amalgam it describes as "very durable" and "more affordable than tooth-colored or gold fillings". On the general question it is unambiguous: "no dental filling lasts forever".

The ADA also states the principle that should govern the conversation: "You have the right to decide, after consultation with your dentist, what treatments and materials are used for your dental care."

The FDA's position on amalgam, quoted exactly

This comes up constantly and is worth reporting precisely rather than summarising. The United States Food and Drug Administration's page on dental amalgam fillings, content current as of 18 February 2021, names groups it considers at greater risk — among them pregnant women and their developing fetuses, women planning to become pregnant, nursing women and their infants, children under six, and people with impaired kidney function or an existing allergy to mercury or the other metals in amalgam.

For those groups the FDA writes that it "strongly encourages the use of non-amalgam restorations (fillings) such as composite resins and glass ionomer cements if your dentist thinks these materials are appropriate for your affected tooth's structure and location". On existing fillings its position runs the other way: "The FDA does not recommend anyone remove or replace existing amalgam fillings in good condition unless it is considered medically necessary by a health care professional", because removal causes unnecessary loss of healthy tooth and a temporary increase in exposure during the process.

Both halves of that belong together. Quoting only the first half is how a page ends up encouraging people to have sound fillings drilled out, which is the opposite of what the agency says.

The English version of the same choice

The NHS charges fillings in Band 2 at £76.60 and crowns in Band 3 at £332.10 — a single step rather than a multiple, and charged once per course of treatment either way. On materials it says: "White fillings are available on the NHS when clinically necessary", that a filling in a front tooth may be white, and that for a back tooth "a more effective option may be a silver-coloured (amalgam) filling", with private costs to discuss if you would prefer white. The page was last reviewed on 13 March 2025.

One last thing worth knowing: the surface count on a filling is what sets its fee, so if a filling is the answer, ask how many surfaces it covers. That is the number every schedule prices from, and it is explained in what dental bonding and composite fillings cost.