Gum disease is caused by bacterial plaque, a sticky film that builds up on your teeth and triggers inflammation in the surrounding tissue. It affects 42% of American adults over 30, and that number climbs to nearly 60% for adults 65 and older. While plaque is the primary trigger, a range of factors from smoking to genetics to hormonal shifts can accelerate the damage or make your gums less able to defend themselves.
Plaque Buildup Is the Root Cause
Hundreds of bacterial species live in your mouth, and many of them are harmless or even beneficial. The trouble starts when certain bacteria attach to your tooth surfaces and begin forming a layered community called a biofilm. The first wave includes species that can anchor directly to the tooth. Once they establish a foothold, more harmful bacteria move in on top of them, including types strongly linked to tissue destruction and bone loss.
If plaque isn’t removed through brushing and flossing, it hardens into tartar (also called calculus), which you can’t remove at home. Tartar creates a rough surface that makes it even easier for more bacteria to accumulate, and it pushes deeper below the gumline where the real damage happens. This is why regular dental cleanings matter: they remove the hardened deposits that daily brushing misses.
Gingivitis vs. Periodontitis
Gum disease has two main stages. Gingivitis is the early, reversible stage. Your gums become red, swollen, and bleed easily when you brush. At this point, no permanent damage has occurred, and improving your oral hygiene can resolve it completely.
When gingivitis goes untreated, it can progress to periodontitis. The gums begin pulling away from the teeth, forming pockets that trap bacteria. These pockets can deepen to several millimeters and sometimes beyond a centimeter. As the infection spreads, it destroys the bone and connective tissue holding your teeth in place. This damage is irreversible. Only 10 to 20% of people with gum disease develop severe periodontitis with tooth loss, but the progression is often painless, which means many people don’t realize how advanced their condition is until significant damage has occurred.
Smoking and Gum Healing
Smoking is one of the strongest risk factors for gum disease. It weakens your immune system’s ability to fight off the bacterial infection in your gums, and it impairs blood flow to gum tissue. That reduced blood flow means your gums heal more slowly after any damage occurs, giving bacteria more time to cause destruction. Smokers also tend to respond less well to gum disease treatment, making the condition harder to manage even with professional care.
How Diabetes Fuels Gum Disease
The relationship between diabetes and gum disease runs in both directions. High blood sugar damages small blood vessels throughout the body, including those in the gums. The vessel walls thicken, blood flow decreases, and waste products build up in the tissue. At the same time, diabetes reduces the effectiveness of immune cells called macrophages, which are responsible for clearing out bacteria and helping wounds heal. The result is gum tissue that’s slower to recover and more vulnerable to infection.
The reverse is also true. Chronic gum inflammation pumps inflammatory molecules into the bloodstream, and these molecules can worsen insulin resistance. Essentially, untreated gum disease can make blood sugar harder to control, which in turn makes the gum disease worse. Breaking this cycle often requires managing both conditions simultaneously.
Hormonal Changes During Pregnancy and Puberty
Rising levels of estrogen and progesterone change how your gums respond to the same amount of plaque that was there before. Estrogen increases the permeability of blood vessels in gum tissue, causing fluid to accumulate and making gums more prone to swelling and bleeding. Progesterone suppresses the local immune response by reducing the effectiveness of the cells that normally keep bacteria in check.
These hormonal shifts also change which bacteria thrive in your mouth. Elevated progesterone encourages the growth of anaerobic bacteria closely associated with periodontal disease. This is why “pregnancy gingivitis” is so common, with gums becoming noticeably inflamed even in women who had healthy gums before becoming pregnant. Similar effects can occur during puberty and menopause, though pregnancy produces the most dramatic changes.
Dry Mouth Removes a Key Defense
Saliva does far more than keep your mouth comfortable. It coats your teeth and gums with a protective layer of mucin that physically blocks harmful bacteria from attaching to surfaces. It also contains antimicrobial compounds that serve as a first line of defense against pathogens. When saliva production drops, bacteria adhere to teeth more easily, the pH balance in your mouth shifts, and the composition of plaque changes in ways that favor disease-causing species.
Dry mouth can result from aging, radiation therapy, autoimmune conditions, or simply breathing through your mouth at night. It’s also a side effect of hundreds of common medications, including antihistamines, antidepressants, and blood pressure drugs.
Medications That Change Gum Tissue
Certain medications cause the gums to physically overgrow, creating deep folds of tissue that trap bacteria and make cleaning nearly impossible. Three drug classes are the most common culprits: seizure medications (particularly phenytoin, which causes overgrowth in about 50% of users), immune-suppressing drugs used after organ transplants (affecting roughly 30% of users), and calcium channel blockers used for high blood pressure (about 20% of users). If you take any of these and notice your gums thickening or growing over your teeth, your dentist can work with your prescribing doctor to explore alternatives or adjust your care plan.
Genetics and Family Risk
Your genes influence how aggressively your immune system responds to bacterial plaque. Some people mount an exaggerated inflammatory response that, while aimed at fighting infection, also destroys surrounding bone and tissue. Others may have genetic variations that weaken their immune defenses in gum tissue. Researchers have studied specific gene markers related to inflammation and vitamin D receptors, though no single gene has been identified as the definitive cause. What’s clear is that genetics can modulate both how easily your gums become inflamed and how quickly you lose the bone that supports your teeth.
If severe gum disease runs in your family, that doesn’t guarantee you’ll develop it. It does mean that consistent oral hygiene and regular dental visits carry extra importance for you.
Vitamin C and Gum Tissue Integrity
Vitamin C plays a direct role in building collagen, which is the structural protein that holds your gum tissue together and anchors teeth to the jawbone. When intake drops below about 10 mg per day (far below the recommended 75 to 90 mg), the result is scurvy: bleeding gums, loosening teeth, and breakdown of the periodontal ligament. Even milder deficiencies can impair wound healing in gum tissue and reduce the antioxidant protection that keeps inflammation in check. Most people get enough vitamin C through a normal diet, but those with very restricted diets or certain digestive conditions may fall short.