What gum disease is

"Gum disease" is the everyday name for a family of inflammatory conditions that affect the tissues surrounding the teeth. Its formal name is periodontal disease, from the Greek peri ("around") and odontos ("tooth"). At its core, gum disease is the body's inflammatory response to a persistent bacterial biofilm — dental plaque — that accumulates where the gum meets the tooth.

That inflammation begins as a superficial, reversible irritation of the gum tissue (gingivitis) and, in some people, progresses into a deeper condition that damages the ligament and bone that hold the tooth in place (periodontitis). Understanding gum disease means understanding that spectrum, not a single event.

The stages: gingivitis to periodontitis

Clinicians typically describe gum disease in stages. The exact classification systems vary, but the practical progression looks like this:

  1. Healthy gums. Pink, firm, and don't bleed with routine cleaning. A small, shallow crevice ("sulcus") exists between the gum and tooth — normally 1–3 mm deep.
  2. Gingivitis. The gum tissue becomes swollen, red, and bleeds easily. The bone and ligament underneath are still intact. See our full Gingivitis Guide.
  3. Early periodontitis. The gum begins to detach from the tooth, deepening the sulcus into a "pocket" (typically 4–5 mm), and the bone starts to erode.
  4. Moderate periodontitis. Pockets deepen further (5–7 mm), bone loss becomes visible on X-rays, and teeth may start to feel loose.
  5. Severe periodontitis. Pockets exceed 7 mm, significant bone loss is present, and tooth loss becomes likely without treatment. See our full Periodontitis Guide.

The critical dividing line is between gingivitis and periodontitis: gingivitis can be reversed by removing the plaque that's causing it. Periodontitis can be arrested, but structural damage is not fully reversible.

Causes and risk factors

The proximate cause of gum disease is dental plaque — a sticky biofilm of bacteria that continuously forms on tooth surfaces. When plaque sits at the gum line for extended periods, it triggers an immune response. In most people, that response contains the bacteria. In some, the response itself contributes to tissue breakdown.

Common risk factors

  • Inconsistent plaque removal. The single largest modifiable factor — skipping brushing, poor technique, or never cleaning between teeth.
  • Smoking and tobacco use. Substantially increases both the risk and severity of periodontitis, and reduces how well treatment works.
  • Diabetes, especially when poorly controlled. There is a well-documented two-way relationship between diabetes and gum disease.
  • Genetics. A meaningful percentage of the population is more genetically susceptible, independent of hygiene.
  • Hormonal changes. Puberty, pregnancy, and menopause can each amplify gingival response.
  • Certain medications. Some blood-pressure drugs, immunosuppressants, and anti-seizure medications cause gum overgrowth that traps plaque.
  • Stress. Chronic stress can suppress immune responses that would otherwise keep bacterial growth in check.

Symptoms to watch for

Gum disease is famously quiet in its early stages. Many of the most reliable signs are subtle and easy to miss:

  • Gums that bleed when you brush or floss, especially consistently.
  • Puffy, red, or tender gum tissue — instead of firm and pale pink.
  • Persistent bad breath or a bad taste that doesn't respond to brushing.
  • Gums that appear to be pulling back, making teeth look "longer."
  • New sensitivity when eating hot, cold, or sweet foods.
  • Loose teeth, shifting bite, or a change in how partial dentures fit.
  • Pus around a tooth or gum abscess (advanced stage; see a dentist urgently).

How dentists diagnose gum disease

Diagnosis typically happens at a routine cleaning. A dental hygienist or dentist will:

  1. Take a health history. Because systemic conditions and medications matter.
  2. Perform a periodontal probing. A small, calibrated probe is gently placed between the gum and tooth at several points around each tooth. Depths are recorded in millimeters. Depths of 1–3 mm are healthy; 4 mm and above signal detachment.
  3. Check for bleeding on probing. Bleeding at a probed site is one of the most reliable indicators of active inflammation.
  4. Take X-rays. Bitewing and periapical films show the height of the bone around each tooth and are the definitive way to confirm bone loss.
  5. Assess mobility, recession, and furcation involvement. Especially in more advanced cases.

Treatment overview

For gingivitis

Treatment is almost always non-surgical: a professional cleaning to remove plaque and tartar, plus improved home care. Gingivitis typically resolves within 1–2 weeks of consistent good hygiene.

For periodontitis

The mainstay is a procedure called scaling and root planing, sometimes described as a "deep cleaning." It removes plaque and tartar from below the gum line and smooths the root surfaces so the gum can reattach. It's typically performed with local anesthesia in one or more visits.

More advanced cases may require:

  • Locally applied antibiotics placed into deep pockets.
  • Short courses of systemic antibiotics for aggressive forms.
  • Periodontal surgery — flap surgery, bone or tissue grafting, or guided regeneration — for pockets that don't respond to non-surgical care.
  • More frequent maintenance cleanings (often every 3 months) for the long term.

Prevention

Prevention is unglamorous and effective. The essentials, in order of impact:

  1. Brush twice a day, thoroughly, with fluoride toothpaste. Technique matters more than force. See our Tooth Brushing Guide.
  2. Clean between your teeth once a day. Floss, floss picks, interdental brushes, or a water flosser — pick something you'll actually use. See our Flossing Guide.
  3. See a dentist regularly. For most adults, every 6 months; some people need every 3–4 months.
  4. Don't smoke. Quitting improves periodontal outcomes even after years of tobacco use.
  5. Manage systemic conditions. Especially diabetes.

For a full walk-through, see the Prevention Center.

Frequently asked questions

Can gum disease be reversed?
Gingivitis, the earliest stage, is reversible with consistent home care and a professional cleaning. Once periodontitis has caused bone loss, the disease can be arrested and stabilized but the lost bone does not grow back on its own.
Is bleeding when I brush always gum disease?
Bleeding is the most common early sign, but it can also be caused by a brand-new flossing routine, medications that affect clotting, or brushing too hard. Bleeding that continues for more than a week or two of consistent gentle care is worth discussing with a dentist.
How fast does gum disease progress?
For most people, progression is slow — months to years between stages. Certain risk factors (smoking, uncontrolled diabetes, some genetic factors) accelerate it substantially.
Do I need special toothpaste?
For most people, any fluoride toothpaste from an established manufacturer is adequate. Toothpastes marketed for 'gum health' generally rely on ingredients like stannous fluoride, which has some evidence for reducing gingivitis but is not a substitute for good technique.
Is gum disease contagious?
The bacteria involved can be transferred between people through saliva, but developing disease depends on many personal factors. Sharing a household with someone who has periodontitis does not mean you will get it.