Gums swell when your body sends extra blood and immune cells to fight off irritation or infection in the tissue surrounding your teeth. The most common trigger is bacterial plaque, but hormonal shifts, medications, nutritional deficiencies, and poorly fitting dental appliances can all cause it too. Over 42% of U.S. adults aged 30 and older have some form of periodontal disease, making swollen gums one of the most widespread health issues most people underestimate.
How Plaque Triggers the Swelling
When plaque (the sticky film of bacteria that builds up on your teeth) sits undisturbed, your immune system treats it as a threat. Within about four days of plaque accumulating along the gumline, your body launches its first response: blood vessels in the gum tissue dilate, fluid flow increases, and white blood cells called neutrophils rush toward the bacteria. These immune cells release enzymes that destroy collagen, the structural protein holding your gum tissue together. At this earliest stage, 5% to 10% of the connective tissue near the gumline is already occupied by inflammatory cells.
After about a week, the damage becomes visible. Gums turn red and bleed easily when you brush or floss. By this point, 60% to 70% of the collagen in the affected area has broken down. The tissue cells themselves start showing damage, and more immune cells pile in. This is gingivitis, and it’s still reversible.
If plaque remains, the inflammation becomes self-sustaining. The body forms a small pocket between the gum and tooth, lined with fragile tissue that bleeds and swells further. Once that pocket deepens beyond about 4 millimeters, the condition crosses into periodontitis, a more serious stage where the bone supporting your teeth begins to erode. Periodontitis isn’t reversible in the same way gingivitis is, though it can be managed.
Hormonal Changes and Gum Sensitivity
Pregnancy is one of the clearest examples of hormone-driven gum swelling. Rising levels of estrogen and progesterone change the blood vessels inside gum tissue, making them more permeable and dilated. Fluid leaks into the tissue more easily, causing puffiness and tenderness. Estrogen specifically alters the cells lining blood vessels, letting more fluid accumulate in the gums. Progesterone, meanwhile, weakens the local immune defense by reducing how effectively white blood cells fight bacterial plaque.
The hormonal shift also changes which bacteria thrive in your mouth. Elevated progesterone supports the growth of specific anaerobic bacteria closely linked to periodontal disease. These bacteria intensify inflammation, which is why many pregnant women notice their gums bleeding or swelling even without changing their brushing habits. One study found that estrogen and progesterone levels accounted for 45% of the variation in the severity of gum inflammation among pregnant participants.
Pregnancy isn’t the only hormonal trigger. Puberty, menstruation, and menopause can all produce similar (though usually milder) effects on gum tissue for the same underlying reasons: shifting hormone levels alter blood flow and immune function in the gums.
Medications That Cause Gum Overgrowth
Certain prescription drugs cause gum tissue to physically enlarge, sometimes dramatically. Three categories of medication are most commonly responsible:
- Blood pressure medications (calcium channel blockers): Nifedipine and amlodipine are the most frequently prescribed ones linked to gum overgrowth, though verapamil and diltiazem can cause it too.
- Anti-seizure medications: Phenytoin is the most well-known culprit, but sodium valproate and several others are also associated with gum enlargement.
- Immunosuppressants: Cyclosporine, commonly used after organ transplants and for autoimmune conditions, is a frequent cause. Tacrolimus and sirolimus carry similar risks.
Drug-induced gum overgrowth usually starts at the small triangles of tissue between teeth (the interdental papillae) and can gradually extend to cover portions of the tooth surface. It tends to worsen when plaque control is poor, so meticulous brushing and flossing can reduce but not always prevent the problem. If you notice your gums growing over your teeth after starting a new medication, your dentist and prescribing doctor can discuss alternatives.
Vitamin C Deficiency
Your body needs vitamin C to produce and maintain collagen, the same protein that gives gum tissue its structure. When intake drops low enough, collagen breaks down throughout the body, and the gums are one of the first places it shows. Symptoms of scurvy, the clinical name for severe vitamin C deficiency, can appear within 4 to 12 weeks of consistently insufficient intake. Gums become swollen, spongy, and dark red, bleeding easily with minimal contact.
The body stores about 1,500 mg of vitamin C at any given time, and clinical signs appear once stores drop below roughly 350 mg. True scurvy is uncommon in developed countries, but marginal deficiency is more common than most people realize, particularly among smokers, people with very restrictive diets, and older adults with limited food variety.
Braces, Dentures, and Local Irritation
Fixed orthodontic appliances create surfaces where plaque accumulates more easily and is harder to remove. Brackets, bands, and the bonding material around them trap food and bacteria against the gumline. Excess resin around brackets has been specifically linked to increased gingival bleeding. Over time, this persistent plaque buildup leads to localized swelling that can affect the gum margin, the tissue between teeth, and even the attached gum tissue farther from the tooth.
Ill-fitting dentures or dental restorations create a similar problem through a different route. They physically rub against gum tissue, causing chronic mechanical irritation. The body responds to this repeated injury by producing more tissue in the area, resulting in lumpy, overgrown gums that may partly cover the irritating appliance. Getting the fit adjusted usually resolves the issue over time.
Abscess vs. Routine Swelling
Not all gum swelling is the generalized puffiness of gingivitis. A dental abscess produces a concentrated pocket of infection that feels and behaves differently. The hallmarks include constant throbbing or sharp pain (not just sensitivity while brushing), pain when chewing, a bitter taste in your mouth, and sometimes a visible bump on the gum that resembles a pimple. Fever is a common sign, as your body fights a more serious localized infection.
Swelling that extends to the glands in your neck or along your jawline signals that the infection may be spreading and needs prompt attention. An abscess won’t resolve with better brushing. It requires professional treatment to drain the infection and address the underlying cause, whether that’s a deep cavity, a cracked tooth, or advanced gum disease.
How Quickly Swollen Gums Can Heal
If the cause is plaque-related gingivitis, the timeline depends on how far things have progressed. Mild gingivitis, caught early, often starts improving within 3 to 5 days of consistent brushing and flossing, with most symptoms resolving in one to two weeks. Moderate cases where tartar (hardened plaque) has built up typically need a professional cleaning and take 10 to 21 days to heal. Severe gingivitis may require three weeks or more, sometimes with multiple dental visits.
The key factor is removing the source of irritation. For plaque-driven swelling, that means thorough daily cleaning and professional removal of tartar you can’t reach with a toothbrush. For medication-induced overgrowth, improvement depends on whether the drug can be switched. For hormonal causes, the swelling often subsides after the hormonal trigger passes (after delivery, for instance), though good oral hygiene during that period prevents the inflammation from causing lasting damage. The American Academy of Periodontology recommends an annual comprehensive periodontal evaluation to catch gum problems before they progress to the point where bone loss begins.