Gingivitis is inflammation limited to the gums. Periodontitis is what happens when that inflammation spreads deeper, destroying the bone and connective tissue that hold your teeth in place. The critical difference is bone loss: gingivitis doesn’t cause it, and periodontitis does. This distinction matters because gingivitis is fully reversible, while the damage from periodontitis is permanent.
How the Two Conditions Differ
In a healthy mouth, the space between your gum and tooth measures less than 3 millimeters when a dentist probes it. With gingivitis, the gums swell and may form deeper pockets, sometimes exceeding 3 mm, but these are “false pockets” caused by swelling rather than tissue destruction. The gum tissue is still attached to the tooth and bone in its normal position.
Periodontitis crosses a line that gingivitis doesn’t. The attachment between gum and tooth breaks down, the connective fibers that anchor the tooth dissolve, and the jawbone itself begins to erode. This is called attachment loss, and it’s the defining feature dentists use to distinguish periodontitis from gingivitis. Once bone is gone, it doesn’t grow back on its own.
Think of it as a progression. Bacteria in dental plaque first irritate the gums (gingivitis). If the inflammation persists long enough, it migrates below the gumline and triggers the body’s immune response against deeper structures. That immune response, while trying to fight infection, ends up destroying your own bone tissue in the process.
What Each Condition Looks and Feels Like
Gingivitis tends to be subtle. Your gums may look redder than usual, feel slightly tender, or bleed when you brush or floss. Many people dismiss these signs because there’s no pain. The teeth themselves feel normal, nothing is loose, and your bite hasn’t changed.
Periodontitis adds a different set of warning signs. As the bone supporting your teeth erodes, the gums pull away and make teeth appear longer. You may notice teeth shifting position, gaps forming where there weren’t any before, or a change in how your bite feels when you chew. Teeth can become loose or sensitive. Pain while chewing is common in more advanced stages. Bad breath that doesn’t respond to brushing can also signal deeper infection below the gumline.
The tricky part is that periodontitis can progress for years without obvious symptoms. Some people don’t realize anything is wrong until a tooth becomes noticeably loose. This is why dental X-rays and probing measurements matter: they detect bone loss before you can feel it.
How Bone Destruction Actually Happens
Your body constantly builds and breaks down bone through specialized cells. The cells responsible for breaking down bone are normally kept in check by the cells that build it. In periodontitis, chronic inflammation tips this balance dramatically. Inflammatory signals flood the area around the tooth roots and activate bone-destroying cells in large numbers, while suppressing the cells that would normally rebuild.
These bone-destroying cells attach to the jawbone surface and release acids and enzymes that dissolve bone tissue. As the bone recedes, the pocket between gum and tooth deepens, creating a sheltered environment where bacteria thrive even further from the reach of your toothbrush. This creates a self-reinforcing cycle: deeper pockets harbor more bacteria, which drive more inflammation, which destroys more bone.
How Common Each Condition Is
Gingivitis is extremely common. Most adults experience it at some point, often without realizing it. Periodontitis is also far more widespread than people assume. Data from the National Health and Nutrition Examination Survey found that 42.2% of U.S. adults aged 30 and older have some form of periodontitis. Of those, about 34.4% have mild or moderate disease, while 7.8% have severe periodontitis. Globally, severe periodontitis affects 5% to 15% of the adult population.
How Dentists Classify Severity
The American Academy of Periodontology classifies periodontitis into four stages based on how much damage has occurred and how complex treatment will be.
- Stage I: Early periodontitis with 1 to 2 mm of attachment loss. Bone loss is minimal, confined to the upper portion of the tooth root. No teeth have been lost to the disease.
- Stage II: Moderate attachment loss of 3 to 4 mm. Bone loss is still in the upper third of the root but more pronounced. Pocket depths reach up to 5 mm.
- Stage III: Attachment loss of 5 mm or more, with bone loss extending to the middle third of the root or beyond. Up to four teeth may have been lost. Pocket depths reach 6 mm or deeper.
- Stage IV: The same level of tissue destruction as Stage III, but with five or more teeth lost. Remaining teeth may be mobile, and the bite may have collapsed or shifted significantly.
Dentists also assign a grade (A, B, or C) that reflects how quickly the disease is progressing. Grade A means slow progression with no measurable bone loss over five years. Grade C means rapid progression, with 2 mm or more of bone loss over five years. Smoking and diabetes both push a case toward a higher grade.
Treatment Differences
Gingivitis responds well to straightforward care. A professional cleaning to remove plaque and hardened tartar, followed by consistent brushing and flossing at home, is usually enough. Most cases of mild gingivitis improve within 10 to 14 days after a cleaning and improved home care. Because no permanent damage has occurred, the gums can return completely to normal.
Periodontitis requires deeper intervention. Standard cleanings only address the tooth surface above and slightly below the gumline. When pockets deepen and bone loss begins, treatment involves scaling and root planing, a more intensive procedure where a dentist or hygienist cleans below the gumline and smooths the root surfaces to help gums reattach. For advanced cases with deep pocketing, surgery may be needed to access and clean areas that instruments can’t reach from the outside. The goal shifts from curing the disease to stopping further destruction and maintaining what remains.
Treatment frequency also changes. Someone with gingivitis might return to a normal cleaning schedule after their gums heal. Someone with periodontitis typically needs more frequent maintenance visits, often every three to four months, for the rest of their life.
Connections to Overall Health
Periodontitis doesn’t stay in your mouth. The chronic inflammation and bacterial load associated with it have well-documented links to other serious conditions. People with diabetes are two to three times more likely to develop periodontitis than people without diabetes, and the relationship runs both directions: periodontitis makes blood sugar harder to control. Diabetic patients with periodontitis face a six-fold higher risk of poor blood sugar management compared to those with healthy gums.
There is also consistent evidence linking periodontitis to an increased risk of cardiovascular disease. The European Federation of Periodontology and the American Academy of Periodontology jointly concluded that the epidemiological evidence for this connection is strong. Researchers have also observed elevated risks for cancers of the lung, pancreas, esophagus, and stomach, as well as kidney disease, in people with untreated periodontitis.
Gingivitis, because it’s confined to the soft tissue and typically short-lived, does not carry the same systemic risks. This is one more reason the distinction between the two conditions matters: catching gum disease while it’s still gingivitis isn’t just about saving teeth, it’s about protecting your broader health.