· 7 min
A receding gum (clinically, gingival recession) is a gum that has moved toward the root and exposes a part of the tooth that used to be covered. You notice it because the tooth looks longer, a yellower band appears near the gum line and, often, cold starts to hurt. The first thing worth knowing: the tissue that was lost does not come back on its own. The second: it can almost always be stopped, and in many cases the root can be covered.
I'm Pablo Atria, co-director of AS Odontología Digital and faculty at NYU College of Dentistry. A few days ago a listener asked me this on Radio Bío Bío: why do gums pull back? I gave her the short answer. This is the long one, with what the evidence says and what we do in the clinic.
A healthy gum ends at the neck of the tooth, right where the enamel stops. When that edge moves down toward the root, the root is exposed. Unlike the crown of the tooth, the root has no enamel: it is covered by cementum, a softer, more porous tissue. That is why an exposed root becomes sensitive to cold, wears more easily and can develop decay in a place where it used to be impossible.
It is far more common than it looks. A systematic review and meta-analysis published in 2025 in the Journal of Dentistry estimated that 81 percent of adults have at least one recession of one millimeter or more, and almost half have one of three millimeters or more. The current classification of mucogingival conditions (Cortellini and Bissada, 2018) lists the typical consequences: hypersensitivity, root caries, lesions at the neck of the tooth and an aesthetic compromise.
On the radio I named three causes: bruxism, the bite and brushing. They are worth ranking by how much weight each carries in the data, because they are not equal.
The 2025 meta-analysis I cited above pooled 22 studies and found a statistically significant association with these factors: periodontitis (by far the strongest), accumulated plaque, occlusal trauma, smoking, alcohol consumption, a frenulum attached very high, a history of periodontal treatment and male sex. Put simply: recession is, before anything else, a problem of a diseased gum or a gum exposed to forces it cannot tolerate.
There is also a terrain factor that does not appear on that list because it is hard to measure in surveys: gum thickness. A thin gum with little keratinized tissue recedes under stimuli a thick gum tolerates without trouble. It is part of what we assess before any cosmetic or orthodontic treatment.
This is the cause everyone knows, and here it is worth being honest about the evidence. A systematic review in the Journal of Clinical Periodontology looked specifically at whether brushing (frequency, force, bristle hardness, technique) predicts the onset and progression of non-inflammatory recession. Of 18 studies, eight found an association with brushing frequency, two found none, and the conclusion was that the data to confirm or refute the link are inconclusive.
Does that change the advice? No. The clinical logic is the same one I gave the journalist with the mashed-potato pot: if what you are removing is a soft film, a soft sponge cleans better and without scratching than steel wool. A soft-bristled brush, in short circular strokes and without pressure, removes soft plaque without wearing the gum or the root. What is clear is that aggressive brushing on a gum that is already thin or already inflamed harms it. Brush hardness is not the origin of the problem, but it can be the final push.
This is the point I most want to get across. Many patients arrive saying their gums have always bled, as if it were a personal trait. It is not. A healthy gum does not bleed: not when brushing, not with floss, not when biting an apple. Bleeding means inflammation, and inflammation has two stages. Gingivitis is reversible: it is treated and the gum returns to normal. Periodontitis is not: bone is lost around the tooth, the gum follows it down and recession appears. That is why periodontitis is the factor with the strongest association in the meta-analysis, by a wide margin.
Periodontitis also does not stay in the mouth. The consensus report of the European Federation of Periodontology and the World Heart Federation (2020) summarizes the evidence for an independent association between periodontitis and cardiovascular disease, and the same low-grade chronic inflammation has been linked to diabetes and metabolic syndrome. If you have recession and bleeding at the same time, the order is clear: treat the disease first, think about covering roots second. And once it is under control, periodic maintenance is not optional, because periodontitis tends to return when follow-up is abandoned. I wrote about the difference between the two stages in gingivitis: why gums bleed.
Occlusal trauma, meaning a tooth that receives more force than its support can tolerate, appeared in the meta-analysis with three times the odds of recession. In practice we see it in patients who clench or grind, and in bites where one tooth hits before the others. The gum on that tooth is usually the one that drops, often with a notch at the neck of the tooth.
Here a night guard (in Chile we call it a plano de relajación) has a concrete job: it spreads the force and keeps the teeth from striking each other during the night, which protects enamel and restorations. It does not make gum grow, but it removes one of the forces pushing it down. One detail I repeated in the interview: it has to be custom-made from a digital capture of your mouth. The ones you soften in hot water and bite into control neither the bite nor the thickness, and can make the problem worse. If you suspect you clench, start with what bruxism is and how to know if you have it.
No. Lost tissue does not regenerate spontaneously, and no rinse, toothpaste or supplement makes it grow. What can be done is two things: stop the progression by correcting the cause (inflammation, plaque, force, habit), and cover the root with periodontal plastic surgery when indicated.
The technique with the best support is the coronally advanced flap with a connective tissue graft taken from the patient's own palate. The Cochrane review of root coverage procedures concludes that the connective tissue graft offers a slight advantage when the goal is both to cover the root and to gain keratinized gum, and that, on weaker evidence, acellular dermal matrices appear to be the substitute that comes closest when a second surgical site is to be avoided. How much can be covered depends on the type of recession: if the bone and gum between the teeth are intact, complete coverage is predictable; if support between teeth has already been lost, the goal is partial. That is decided in the examination, not from a photo.
What to do. A soft-bristled brush, short circular strokes, no pressure, twice a day with fluoride toothpaste. Clean between the teeth every day: floss, interdental brush or water flosser, whichever you will actually use. As I told the journalist, a habit you keep is worth more than the best technique you drop after a week. If manual technique is hard for you or your hands are less dexterous, a powered brush helps: the Cochrane review found 11 to 21 percent less plaque and 6 to 11 percent less gingivitis depending on how long it was used (under and over three months), with oscillating-rotating brushes as the group with the most evidence. With good manual technique the difference is smaller.
What not to do. Do not scrub the receded area harder to make it whiter: root cementum wears away. Do not apply bleaching gel to exposed roots without a prior evaluation: gel in direct contact with the root can inflame the pulp. And if cold already bothers you, treat it as a signal rather than a condition to live with: in tooth sensitivity I explain what causes it and what works.
See a dentist if you notice bleeding when brushing, a tooth that looks longer than a year ago, new sensitivity to cold, a loose tooth or a recession that is advancing. At AS Odontología Digital the first step is a complete periodontal examination, measuring every site, plus clinical photographs and an intraoral scan that let us compare the gum position at later check-ups with precision instead of relying on memory. With that we define whether the problem is inflammatory, mechanical or mixed, whether periodontal disease has to be treated first, whether a night guard is needed, and whether root coverage is indicated and with what realistic expectation. That order matters: covering a root over a gum that is still inflamed throws the work away.
If this article left you with questions, explore the related services or book an evaluation at AS Odontología Digital in Vitacura.
Book an evaluationNo. Lost gum tissue does not regenerate on its own, and no toothpaste, rinse or supplement makes it grow. What is possible is to stop the progression by correcting the cause and, when indicated, to cover the root with a connective tissue graft or an equivalent technique.
A soft-bristled one, with short circular strokes and no pressure. Hard and medium brushes are reserved for cleaning dentures and night guards, not teeth.
No. A healthy gum does not bleed when brushing, flossing or eating. Bleeding means inflammation: gingivitis if it is reversible, periodontitis if bone has already been lost. Both deserve an evaluation.
Occlusal trauma, which includes clenching and grinding, is associated with higher odds of recession in the studies. A custom-made night guard spreads that force and protects the teeth, although it does not regrow lost gum.
The evidence is less clear than people think: a systematic review concluded the data are inconclusive. Even so, aggressive brushing on a thin or inflamed gum damages it, and a soft brush removes plaque without that risk.
Only after an evaluation. Bleaching gel in direct contact with an exposed root can inflame the pulp and cause intense pain. In the clinic the root is protected or the protocol is adjusted.
A periodontist. At AS Odontología Digital the periodontal examination defines whether gum disease has to be treated first, whether a night guard is needed for bruxism and whether root coverage is indicated.
