This article is general information for our patients, not a diagnosis. If something in your mouth hurts, changes, or worries you, have it examined.
Almost every toothache is the same message in a different accent: the nerve inside a tooth is in trouble. What changes — and what eventually decides whether a tooth needs a filling, a root canal, or to come out — is how the pain behaves. Those patterns are worth understanding, and below I’ll walk through how I read them.
One thing first, because it matters. None of the clues below is a diagnosis on its own. What actually settles it is putting them together — your history, an exam, how the tooth responds to specific tests, and an X-ray — all at once. A symptom that points one way alone can point somewhere else entirely once the rest of the picture is in. So use this to understand your pain and gauge how urgent it is, not to land on an answer.
The patterns I weigh
Inside every tooth is a soft core of nerves and blood vessels (the pulp), sealed in a hard chamber. When decay, a crack or an old deep filling lets bacteria reach it, the nerve inflames — and, trapped with nowhere to swell, even a little inflammation hurts out of proportion to the size of the hole. These are the patterns I weigh — clues that point somewhere, not verdicts:
| What you notice | What it can point toward |
|---|---|
| Quick twinge to cold or sweet, gone in seconds | Often simple sensitivity — usually mild |
| An ache that lingers minutes after hot or cold | A nerve that may be inflamed beyond healing |
| Throbbing that starts on its own, worse at night | A dying nerve or early infection |
| A sharp jolt when you bite one spot | A possible crack or a filling sitting high |
| Tender to press, feels slightly “tall” | Inflammation that may have reached the bone |
| A gum pimple that comes and goes painlessly | A long-standing infection quietly draining |
| Facial swelling or fever | A spreading infection — treat as urgent |
The first thing I weigh is how long the pain outlasts its trigger — and even that can fool you. The same cold that gives a healthy nerve a one-second twinge can briefly relieve a dying one, so two people both describing “pain with cold” can have completely different problems. That’s why the pattern alone is never the whole story.
Sensitivity, and the moment it changes
A brief twinge to cold or sweet that fades within a second or two is usually sensitivity — the least worrying pain here. It comes from the softer layer under the enamel (the dentine) being exposed, and it often settles once the cause is treated. The change worth noticing is when that quick twinge becomes an ache that lingers after the cold is gone — that tends to mean the problem has moved deeper, beyond what a toothpaste can reach.
When a nerve may be beyond healing
When an ache carries on for minutes after the trigger, or starts on its own, the nerve may be inflamed past the point of recovery (irreversible pulpitis). It’s often hard to pin down — you might know it’s “somewhere on the lower left” but not which tooth, because neighbouring teeth share nerve pathways. If that’s where things are, the options usually narrow to a root canal to remove the infected nerve, or removing the tooth — but which one, and whether the nerve really is beyond saving, isn’t something I’d settle from symptoms alone.
When the pain suddenly stops
A tooth that throbs for days and then goes quiet hasn’t necessarily healed. Often the nerve has simply died and the infection carries on with less to warn you — so a sudden easing can be the least reassuring sign of all. If a bad toothache disappears on its own, I’d still want to look.
Why it throbs worse at night
Throbbing is your own pulse pushing against inflamed tissue with nowhere to expand; lying down sends more blood to your head and raises the pressure inside the tooth, so the ache that was bearable by day keeps you up at 2 a.m. Extra pillows help a little — but a tooth throbbing on its own rarely settles for good by itself.
What decides the treatment
Whether a tooth needs a filling, a root canal, draining, or removal comes down to things your symptoms can’t tell you: how it responds to a cold test, whether it’s tender to a specific tap, and what an X-ray shows at the root tip and in the bone around it. Any one of those, on its own, can mislead. It’s reading them together — alongside what you’ve told me — that points to an answer, and that’s the part we put together in the chair.
How an abscess builds
If a nerve dies untreated, bacteria collect at the root tip and the body walls off the infection as pus. It tends to run in stages: deep decay, a dying nerve (pain often fades here), tenderness to bite as it reaches the bone, then a painful abscess that either drains through a gum pimple or — the dangerous version — spreads into the face and neck. A painless gum pimple (a sinus tract) isn’t “gone”; it’s an infection quietly draining through a channel in the bone. A tooth slowly turning grey usually means the nerve has died and its dark pigments have soaked into the tooth. None of these hurt much, which is exactly why they get missed.
Getting through until you’re seen
Over-the-counter painkillers can take the edge off, but they only quiet the symptom — they don’t treat the tooth, and needing them around the clock is itself a sign to be seen. Because dental pain is largely an inflammation problem, an anti-inflammatory type often helps most; but which one is right for you, and how much, is a question for your pharmacist — it matters if you take other medicines or have a health condition. Two things to avoid: don’t rest an aspirin against the gum (it burns the tissue and does nothing for the tooth), and don’t lean on a leftover course of antibiotics — a dead tooth has no blood supply and abscess pus is walled off, so antibiotics can’t reach the source, and any relief is temporary.
When a toothache can’t wait
A few toothaches are time-critical, because infection can spread toward the throat. Go straight to a hospital or call 911 for swelling in the floor of the mouth or under the jaw on both sides, a raised tongue or muffled voice, trouble swallowing your own saliva, or any difficulty breathing — or swelling spreading toward your eye or neck. Short of those, severe constant pain, a fever with face swelling, or a broken tooth are reasons to call us promptly at 705-721-9229. A knocked-out adult tooth is even more time-critical — what to do for a knocked-out tooth covers the first hour, which often decides whether it can be saved. If you’re unsure, read more about the warning signs that a dental problem is an emergency, or just phone and describe it — I’d far rather hear from you early.
What happens when you come in
The first job is diagnosis, and it’s the part that can’t be done at home: we press and tap to find the tender tooth, use cold to see which nerves are alive, and take an X-ray — then read all of it together. Those few minutes usually pinpoint what the symptoms couldn’t. Comfort comes first: a local anaesthetic (freezing), and draining any abscess that’s come to a head. Only then do we treat the cause — usually a root canal for a tooth worth keeping (here’s how a root canal saves an infected tooth), or removing one too far gone. We also keep room for emergency dental care here in Barrie, so people in real pain aren’t left waiting.
If you have a toothache that won’t settle, a gum pimple that keeps returning, a darkening tooth, or any swelling, our team at Prince William Way Dental in Barrie will find the cause and help you decide what to do next. Call 705-721-9229 or visit our contact page.
