Warning Signs After a Dental Injury

Most dental injuries heal without further problems once the initial treatment is done. But a tooth’s nerve can occasionally be affected by an injury even when everything seemed fine at first — sometimes weeks or months later, and often without warning. Knowing what to look for means you catch it early, when treatment is simplest.

Why this can happen after the injury seems to have settled

Every tooth has a nerve and blood supply running through its centre. An injury — even one that looked minor, or one where the tooth itself was successfully saved — can sometimes damage this without it being obvious straight away. The tooth can look and feel completely normal for weeks, then start showing signs that something has changed. This isn’t a sign that anything was done wrong at the time; it’s a known, documented possibility with traumatic dental injuries, which is why follow-up matters as much as the initial response.

The main signs to watch for

• Colour change — the tooth turning grey, yellow, or noticeably darker than the teeth next to it. This is one of the more common and visible signs, and can appear gradually.
• Swelling or a gum boil — a small swelling, or what looks like a spot or boil on the gum near the affected tooth, sometimes described as a “gum abscess.” This can come and go rather than staying constant.
• Pain returning after it had settled — discomfort that comes back after an initial period of things feeling fine, particularly if it’s worse when biting or with temperature.
• New or unexpected mobility — a tooth that had settled back into place becoming loose again, without a new injury to explain it.
• A change in how the bite feels — the affected tooth, or teeth near it, feeling different when biting down compared to before.

How long after the injury can this appear?

There’s no fixed timeline — it varies by injury type, by tooth, and by individual. Some changes appear within a few weeks; others take months. This is exactly why a single follow-up appointment isn’t always enough on its own, and why it’s worth knowing what to watch for yourself in the meantime, rather than assuming that “no news is good news.”

Does this apply to every type of injury?

Yes, though the specifics vary slightly by injury:

• Knocked-out and replanted tooth — some colour change in the weeks after replantation can be part of normal healing and expected monitoring; a dentist will usually explain what’s expected for that specific tooth. New or worsening darkening, swelling, or pain are what to flag.
• Chipped or broken tooth — watch for colour change, swelling, or new sensitivity, even if the original chip seemed minor.
• Loose tooth — watch for the tooth becoming loose again after it had firmed up, alongside colour change or pain.
• Displaced tooth (pushed in, out or sideways) — watch for the same signs, alongside any change in how the tooth sits or the bite feels.
• Baby tooth — colour change is common and often not a concern on its own, but swelling, pain, or a gum boil should still be checked, since this can occasionally affect the permanent tooth developing underneath.

For the initial first-aid steps for each of these, see the relevant guide:

• What to do if a permanent tooth is knocked out
• What to do if a baby tooth is knocked out
• What to do if a tooth is chipped or broken
• What to do if a tooth becomes loose after an injury
• What to do if a tooth is pushed in, out or sideways

What to do if you notice any of these signs

Contact a dentist and explain that the tooth was previously injured, including roughly when and what happened. This isn’t usually a 999 or A&E situation — book at the earliest appointment available, sooner if there’s significant pain or swelling. If you’re unsure where to go, see dentist, NHS 111, A&E or 999.

What if nothing seems wrong at all?

If you were given a follow-up appointment by a dentist, it’s worth keeping it even if the tooth looks and feels fine — some changes aren’t visible to you and are picked up on examination or an X-ray. If you weren’t given one and it’s been a while since the injury, it’s still reasonable to get the tooth checked, particularly for a permanent tooth that was knocked out, displaced, or significantly loosened.

Print this before you need it

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Related guides

• What to do if a permanent tooth is knocked out
• What to do if a baby tooth is knocked out
• How to tell a baby tooth from a permanent tooth
• What to do if a tooth is chipped or broken
• What to do if a tooth becomes loose after an injury
• What to do if a tooth is pushed in, out or sideways
• Dentist, NHS 111, A&E or 999: where to get help for a dental injury

References

• International Association of Dental Traumatology (IADT), Guidelines for the Management of Traumatic Dental Injuries, 2020 (current as of August 2026)
• American Association of Endodontists, Traumatic Dental Injury Guidance, April 2026
• NHS, Knocked-out tooth, nhs.uk

This guide does not replace assessment by a dentist or emergency service. It reflects current international and UK guidance, reviewed by Dr Yousuf Ibrahim, BDS.