A sharp twinge from cold water, and a tongue that finds a small ledge where a lower tooth meets the gum, is how many people first notice gumline wear. The groove is not decay. It is a loss of tooth structure from wear, and in most mouths more than one habit or condition has contributed. Working out which ones apply to you is what decides whether it keeps deepening.
Dentists call it a non-carious cervical lesion
The "cervical" part refers to the neck of the tooth, the narrow band where the crown meets the root. Enamel is thin there, and once the gum has pulled back a little, the softer root surface is exposed. That makes the area easy to wear. The lesions can be saucer shaped and smooth, or sharp and wedge shaped, and they become more common as people get older.
Because they are not caused by bacteria, they do not spread like a cavity. They can still be sensitive, collect plaque along their edge and catch the eye in a smile, so they are worth having looked at.
Hard brushing is a common contributor
Toothbrush abrasion comes from mechanical rubbing. A lot of pressure, a back-and-forth sawing stroke and an abrasive toothpaste can each add to it, especially on exposed root surfaces, which are softer than enamel. The wear is often seen on the canines and premolars.
Abrasion and gum recession often travel together. Heavy brushing has been linked with gum recession, although studies have not settled whether it is a cause, and once a root is exposed it wears faster than enamel would.
Acid makes the surface easier to wear
Acid does not usually carve a notch on its own, but it softens the outer surface of the tooth for a while after contact. Soft drinks, sports drinks, citrus, wine, vinegar and stomach acid from reflux all do this. Laboratory studies show that a softened surface wears more easily when it is brushed, and this combined effect may be one reason gumline lesions can appear in people who believe they brush gently. Our articles on enamel erosion and reflux and teeth go further into the acid side.
Abfraction is a theory still under debate
Abfraction describes the idea that heavy biting, clenching or grinding bends the tooth slightly, concentrating stress at the neck until tiny pieces of enamel and dentine break away. It would explain why some lesions sit on a single tooth with a heavy bite, or extend under the gum where a toothbrush cannot reach.
The support for it comes mostly from laboratory and computer stress models, and clinical studies have produced mixed results. Most researchers now treat bite stress as a possible contributor that may add to abrasion and acid wear, rather than a cause that works alone. If grinding is part of the picture, a night guard may be suggested to protect the teeth while you sleep.
Matching the fix to the cause
| Contributor | Signs that point to it | What usually helps |
|---|---|---|
| Abrasion | Worn bristles within weeks, notches on several neighbouring teeth | Soft brush, light grip, small circular strokes, a pressure sensor on an electric brush |
| Acid wear | Frequent acidic drinks or reflux, smooth shiny surfaces elsewhere | Fewer acid exposures, water after acidic food or drink, a low-abrasion fluoride toothpaste |
| Bite stress | Grinding, clenching, worn biting edges, a lesion on one heavily loaded tooth | Bite assessment and, where suitable, a night guard |
Repairing the notch, and when to leave it
A shallow, comfortable lesion is often watched rather than filled, with the habits behind it changed first. Clinical photographs taken at check-ups make it easier to tell whether it is stable or slowly deepening.
When a notch is deep, sensitive, trapping food or affecting how a smile looks, a tooth-coloured filling can rebuild the area and often settles the sensitivity. Desensitising toothpaste may help in the meantime. If the gum has receded a long way, a gum graft is sometimes discussed. Fillings at the gumline can wear or come loose if the original cause continues, so a change in brushing technique matters just as much as the repair. Gentler brushing also helps the gums, which our guide to bleeding gums touches on.
Common questions
Will the notch keep getting deeper?
It can, if the causes stay the same. Gentler brushing and less frequent acid exposure are the usual ways to slow it, and check-ups show whether that is working.
Does an electric toothbrush cause abrasion?
Not by itself. Used lightly, with the brush head guided along the teeth rather than scrubbed, an electric brush may reduce pressure, especially one with a pressure warning.
Why does only one tooth have a notch?
A single lesion can come from that tooth taking more load in the bite, sitting further out in the arch so it gets more brushing, or having less gum covering it. Your dentist or OHT can check which applies.
If you have found a groove near the gumline or a tooth has turned sensitive to cold, our general dentistry team can work out what is wearing it and whether it needs repair. Our current deals page shows what a check-up includes.
