A Swelling on the Gum, and the Tooth Was Perfectly Alive

Quick answer: Not every dental abscess comes from a dead nerve. A periodontal abscess arises in a deep gum pocket beside a tooth whose nerve is entirely healthy. It is treated by cleaning out the pocket, not by root canal treatment — and getting that distinction wrong costs a healthy nerve.

The call

Thursday afternoon, and a swelling that had gone from nothing to the size of an olive in about six hours.

Sarah, 54, from RBS Daled, phoned describing a tender lump on the gum beside a lower back tooth, a bad taste, and a tooth that felt slightly high when she bit.

She had eaten a salad the previous evening.

What we found

A fluctuant swelling on the cheek side of the lower left first molar, roughly 12mm across, discharging when pressed. The tooth was tender to bite and slightly mobile.

Then the finding that changed everything: it responded normally to cold. A brief, sharp reaction that stopped immediately. The nerve was alive and healthy.

Probing found a 9mm pocket on the cheek side of that tooth — 3mm everywhere else around it. The x-ray showed bone loss down the side of the root, and, crucially, no dark area at the root tip.

That is a periodontal abscess, and it differs from the more familiar kind at almost every point:

Periodontal abscess. Starts in a deep gum pocket. The tooth is alive and responds to cold. The swelling sits beside the root, at the level of the gum. There is usually a deep pocket at that one site. Rapid onset, often triggered when something blocks the pocket's drainage — a seed, a fragment of food, or debris pushed in.

Periapical abscess — the type in most of our other stories. Starts in a dead nerve. No response to cold. The swelling sits over the root tip, higher in the sulcus. There is a dark lesion at the apex on the x-ray. Usually preceded by weeks of toothache.

The treatments do not overlap. A periodontal abscess needs the pocket opened and cleaned. Root canal treatment would achieve nothing except the loss of a healthy nerve.

The salad was almost certainly relevant: a seed or fragment lodged in a pre-existing deep pocket, sealing it, and the bacteria already living there multiplied behind the blockage.

What we did

Drainage through the pocket. Local anaesthetic, then careful instrumentation into the pocket to open the drainage path and flush out the contents. Pus released immediately, and the pressure — which is what makes these so painful — went with it. We irrigated thoroughly with saline and chlorhexidine.

Debridement of the root surface within the pocket, as far as could be tolerated at an acute visit.

No antibiotics. There was no fever, no spreading swelling, no systemic involvement. Drainage was achieved. Prescribing on top of adequate drainage in a healthy patient adds nothing.

No root canal, for the reason above.

She was reviewed at 48 hours, comfortable, with the swelling resolved.

The outcome

The acute episode settled within three days. Two weeks later we completed proper debridement of the pocket, and at the three-month reassessment it measured 5mm — improved but still a site needing watching.

The wider point: an abscess like this is a flare-up of untreated gum disease, not an isolated accident. She had 5 to 6mm pockets elsewhere that had never been diagnosed. She is now on three-monthly maintenance and has had no further episodes.

What to do if this happens to you

1. Be seen the same day. Pressure in a closed space is what causes the pain.
2. Rinse with warm salt water, and do not squeeze the swelling.
3. Mention anything you ate with seeds, husks or hard fragments.
4. Ask whether the tooth is alive. A cold test takes seconds and determines the entire treatment.
5. Do not accept a root canal without a vitality test. A tooth that responds to cold does not need one.
6. Follow up on the gum disease. The abscess is a symptom of it, not a standalone event.

Painful swelling on the gum? Ramat Beit Shemesh Urgent Dental Care tests the nerve before deciding what it is. 055-985-8845 · WhatsApp https://wa.me/972559858845 · Harav Kook 28/1, Beit Shemesh

This is a composite clinical story. It reflects a presentation we see regularly in Beit Shemesh and Ramat Beit Shemesh; the name and details are illustrative and are not those of a real patient.