Gum disease is an infection of the tissues that hold your teeth in place, caused by bacteria that build up along and below the gum line. It affects about 42% of American adults over age 30, and nearly 60% of those 65 and older. It ranges from mild inflammation that’s fully reversible to severe bone loss that leads to tooth loss.
How Gum Disease Starts
Your mouth naturally contains hundreds of species of bacteria. When you eat, these bacteria feed on sugars and starches and form a sticky film called plaque on your teeth. Brushing and flossing remove most of it, but any plaque left behind begins to harden. Within about 10 to 20 days, plaque mineralizes into a rock-hard deposit called tartar (or calculus) that you can’t remove with a toothbrush. Tartar creates a rough surface where even more bacteria accumulate, and it sits right against your gum tissue.
Your immune system responds to this bacterial buildup by sending inflammatory cells to the area. That inflammation is what actually damages your gums and, eventually, the bone underneath. In other words, gum disease isn’t just bacteria eating away at tissue. It’s your own immune response, triggered by those bacteria, that does much of the destruction.
Gingivitis vs. Periodontitis
Gum disease has two broad phases. The first, gingivitis, is inflammation limited to the gum tissue itself. Your gums may look red or puffy and bleed when you brush or floss, but the bone and ligaments anchoring your teeth are still intact. Gingivitis is reversible with better oral hygiene and professional cleaning.
When gingivitis goes untreated, it can progress to periodontitis, where the infection spreads below the gum line and begins destroying the bone that supports your teeth. The gums pull away from the tooth roots, forming deeper pockets that trap more bacteria and become harder to clean. This is the point where permanent damage starts. Periodontitis doesn’t reverse on its own, and treatment becomes more involved the further it progresses.
What Gum Disease Feels Like
The tricky thing about gum disease is that it’s often painless in its early stages, so many people don’t realize they have it. The earliest signs are subtle: gums that look reddish or purplish instead of pink, slight swelling, and bleeding when you brush or floss. Healthy gums are firm to the touch and don’t bleed.
As the disease progresses, symptoms become harder to ignore:
- Persistent bad breath or a bad taste that doesn’t go away after brushing
- Gum recession, where your gums visibly pull back from your teeth, making teeth look longer
- Pain when chewing
- Pus along the gum line, a sign of active infection
- Loose teeth or teeth that shift position, changing the way your bite feels
By the time teeth feel loose, significant bone loss has already occurred.
How Dentists Measure It
During a dental exam, your dentist or hygienist uses a small probe to measure the depth of the space between each tooth and the surrounding gum. In a healthy mouth, these pockets measure 1 to 3 millimeters deep. Pockets of 4 mm or deeper signal a problem. Depths of 5 to 7 mm indicate moderate periodontitis with notable bone loss, and pockets of 8 mm or more point to severe disease.
Dentists also use X-rays to see how much bone has been lost around your teeth. The American Academy of Periodontology classifies periodontitis into four stages based on these measurements. Stage I involves only minor attachment loss and shallow pockets. Stage II shows slightly more damage but no tooth loss. Stage III means deeper pockets, vertical bone loss, and potential loss of up to four teeth. Stage IV is the most severe, with extensive bone destruction, five or more missing teeth, and teeth that may be drifting or loose enough to affect your ability to chew.
Risk Factors
Poor oral hygiene is the most direct cause, but several other factors raise your risk considerably. Smoking is one of the strongest. Smokers have twice the risk of gum disease compared to nonsmokers, and smoking also makes treatment less effective because it reduces blood flow to the gums and slows healing. The more you smoke, the worse the outlook: people who smoke 10 or more cigarettes a day tend to see the fastest progression.
Diabetes and gum disease have a two-way relationship. High blood sugar promotes gum infection, and gum infection makes blood sugar harder to control. People with poorly managed diabetes (those with higher long-term blood sugar levels) face a particularly aggressive form of the disease. Other risk factors include hormonal changes during pregnancy, certain medications that reduce saliva flow, genetic predisposition, and conditions that weaken the immune system.
Connections to Other Health Problems
Research has found associations between periodontitis and several conditions beyond the mouth, including cardiovascular disease, stroke, Alzheimer’s disease, rheumatoid arthritis, obesity, and certain cancers. The relationship with diabetes is the best studied and appears to run in both directions: treating gum disease in diabetic patients can improve blood sugar control, and managing blood sugar helps protect the gums.
It’s worth being clear about what “association” means here. These links are real and consistent across studies, but scientists haven’t proven that gum disease directly causes heart attacks or dementia. As the American Dental Association has noted, telling patients that gum infections cause a range of non-oral diseases isn’t supported by existing evidence. What is clear is that chronic inflammation anywhere in the body isn’t good for you, and keeping your gums healthy removes one source of it.
Non-Surgical Treatment
The first-line treatment for periodontitis is a deep cleaning procedure called scaling and root planing. It’s more thorough than a standard cleaning. After numbing your gums with local anesthesia, your dentist or hygienist uses hand instruments or ultrasonic tools to scrape away plaque and tartar from both above and below the gum line. Then they smooth the rough spots on your tooth roots, which removes places where bacteria tend to reattach and helps your gums heal snugly against the tooth surface.
The procedure is typically done in two visits, one side of the mouth at a time. Your dentist may also place antibiotics directly around the tooth roots or prescribe oral antibiotics to help knock down the infection. After treatment, you’ll return for follow-up visits so your dentist can re-measure pocket depths and check whether the gums are reattaching. For mild to moderate periodontitis, this is often enough to stop the disease from progressing.
Surgical Treatment for Advanced Cases
When pockets remain deep after scaling and root planing, or when bone damage is too extensive, surgery becomes necessary. The most common procedure is osseous surgery. A periodontist makes an incision along the gum line, folds back the gum tissue to expose the tooth roots and underlying bone, then cleans the roots and reshapes damaged bone to eliminate the deep pockets where bacteria hide. In areas where bone has been lost, the surgeon may place bone grafts or special membranes to encourage regrowth. The gums are then repositioned and stitched closed.
A newer approach uses laser energy to kill bacteria and remove diseased tissue while preserving healthy tissue, which can mean less discomfort and faster healing. Regardless of the technique, the goal is the same: reduce pocket depths to a range you can maintain with regular brushing, flossing, and professional cleanings. After surgical treatment, most patients need periodontal maintenance visits every three to four months rather than the standard twice-yearly cleaning.
Preventing Gum Disease
Prevention comes down to disrupting the bacterial buildup before it causes damage. Brushing twice a day removes plaque from tooth surfaces, and flossing once a day cleans the spaces between teeth where a brush can’t reach. These are the areas where gum disease typically starts. An antimicrobial mouthwash can help reduce bacteria further, though it’s not a substitute for mechanical cleaning.
Regular dental visits matter because even with excellent home care, some tartar buildup is almost inevitable, and only professional instruments can remove it. If you smoke, quitting is one of the single most impactful things you can do for your gum health. And if you have diabetes, keeping your blood sugar well managed protects your gums just as it protects your kidneys, eyes, and blood vessels.