When a cavity doesn't need the drill

The drill is the part most people dread. A cavity doesn't always need one.

Dentistry has gentler options for some kinds of decay. They aren't right for every situation. When they fit, they stop the decay while removing less of the tooth — sometimes without a drill at all.

Stopping decay with a brush-on liquid

One of the simplest is silver diamine fluoride, or SDF — a liquid we paint onto a cavity to stop it from growing. It takes no drill, no numbing, and about a minute per tooth. It's especially useful for young children, for older adults with cavities on exposed roots, and for anyone who's anxious about dental work.

A 2024 Cochrane review — a careful summary of all the studies on a question — found that "SDF probably also helps prevent new root caries," and that it "may help arrest caries in the primary dentition," meaning baby teeth. For some other uses the same review is candid that "the evidence is very uncertain," and we'll tell you which case yours is.¹

SDF has one trade-off: it darkens the spot it treats, turning the decayed area dark brown or black, and that stain is permanent.² On a back baby tooth, most parents gladly accept it. On a tooth that shows when you smile, we'd talk it through first.

Removing less, on purpose

For deeper cavities, the careful move is to take out less of the tooth. The old instinct was to drill away every bit of softened dentin, but on a deep cavity that can mean drilling right down to the nerve. Leaving a thin layer behind and sealing over it keeps the drill away from the nerve. A Cochrane review of caries treatments found that these minimal-removal approaches "have a lower risk of failure" than conventional drilling and filling.³ One example is the Hall Technique, which seals a decayed baby tooth under a metal crown without drilling. Because the deep layer is never exposed, the nerve is less likely to be breached — and a breached nerve is what leads to a root canal.

What it can't do

None of this replaces a filling or a crown when a tooth needs one. A collapsed cusp, decay into the nerve, or a cavity under an old restoration still calls for the conventional fix. The research is still "very uncertain" in places. We aren't trying to avoid treatment; we're trying to use the least that gets a tooth healthy and keeps it that way.

If you have a cavity and you're hoping for the gentlest route that will work, ask. Sometimes the answer is yes.