Gingivitis develops when bacterial plaque builds up along your gumline and triggers an inflammatory response in the surrounding tissue. It’s extremely common: over 42% of American adults aged 30 and older have some form of periodontal disease, with gingivitis being the earliest and most reversible stage. While poor oral hygiene is the primary driver, several other factors, from hormones to medications, can make your gums more vulnerable.
Plaque Buildup Is the Primary Cause
Your mouth naturally harbors hundreds of bacterial species. When you eat, bacteria feed on leftover sugars and starches and form a sticky, colorless film called plaque on the surface of your teeth. In a healthy mouth, early plaque is relatively simple, made up mostly of common bacteria that your immune system handles easily.
Problems start when plaque isn’t removed regularly. Over the course of days, the bacterial community grows more complex. Harmful species, particularly certain oxygen-avoiding bacteria, begin to dominate. As these bacteria multiply in the narrow crevice between your teeth and gums, they release substances that your body recognizes as threats. Your immune system responds by sending white blood cells to the area, releasing inflammatory signals, and increasing blood flow to the tissue. That’s why inflamed gums look red, feel swollen, and bleed easily when you brush or floss.
Under normal circumstances, your immune cells destroy the invading bacteria and then die off in an orderly way, allowing inflammation to resolve and tissue to heal. But when plaque keeps accumulating faster than your body can manage, the inflammation never fully shuts down. It becomes chronic, and that persistent low-grade immune response is what damages the soft tissue of your gums. Left unchecked, this process can progress from gingivitis into full periodontal disease, where the bone supporting your teeth begins to break down.
Smoking Weakens Your Gum Defenses
Tobacco use is one of the strongest risk factors for gum disease. Smoking suppresses your immune system’s ability to fight off the bacterial infection in your gums. According to the CDC, this means smokers have a harder time clearing gum infections and a harder time healing once damage has occurred. The combination of impaired immunity and slower tissue repair makes smokers significantly more likely to develop gingivitis that progresses to more serious periodontal disease.
Hormonal Changes During Pregnancy and Puberty
Shifts in estrogen and progesterone levels can change how your gums react to the same amount of plaque that wouldn’t normally cause problems. During pregnancy, these hormones increase your gum tissue’s sensitivity to plaque, making it more prone to irritation and infection. This is why “pregnancy gingivitis” is so common, even among women with good brushing habits. Similar hormonal fluctuations during puberty, menstruation, and menopause can also increase gum inflammation.
Diabetes Creates a Two-Way Problem
High blood sugar affects your gums in multiple ways. Diabetes reduces saliva production, which means less of the natural rinsing and antibacterial protection saliva provides. It also increases glucose levels in saliva itself, giving bacteria more fuel to grow and form plaque. Over time, persistently elevated blood sugar leads to gum disease.
The relationship runs in both directions. Once your gums become inflamed, that inflammation can raise blood sugar levels throughout your body, making diabetes harder to control. This feedback loop is why dental care is considered a core part of diabetes management.
Certain Medications Affect Your Gums
Several common drug classes can change your gum tissue in ways that promote gingivitis. Some blood pressure medications (calcium channel blockers), anti-seizure drugs, and immunosuppressants can cause gum tissue to overgrow, creating deeper pockets around your teeth where bacteria collect. Beta-blockers and oral contraceptives have been linked to gum inflammation directly. Other medications that reduce saliva flow, often called “dry mouth” as a side effect, remove one of your mouth’s key defenses against plaque buildup.
If you’ve noticed gum changes after starting a new medication, your dentist can help determine whether the drug is contributing and suggest strategies to manage it.
Braces and Dental Appliances Trap Bacteria
Orthodontic brackets, wires, retainers, and other dental appliances create surfaces where plaque accumulates more easily and is harder to brush away. Research consistently shows that orthodontic treatment is associated with increased bacterial colonization of both teeth and gum tissue. The brackets change the physical environment inside your mouth in ways that favor bacterial growth while simultaneously making effective brushing more difficult. This is why people undergoing orthodontic treatment are often advised to be especially diligent about oral hygiene and may need more frequent dental cleanings.
Low Vitamin C Intake
If your gums bleed easily, it may not be entirely about plaque. A review of 15 studies covering over 1,100 people, along with CDC survey data from more than 8,000 participants, found that low blood levels of vitamin C were associated with increased gum bleeding. Increasing vitamin C intake appeared to help resolve the problem. Severe vitamin C deficiency (scurvy) has long been known to cause bleeding throughout the body, but even moderately low levels seem to affect gum health.
The recommended daily intake is 90 mg for adult men and 75 mg for adult women. Foods like bell peppers, kiwis, oranges, and kale are rich sources. A daily supplement of 100 to 200 mg can also help if your diet falls short.
Other Factors That Increase Your Risk
- Crooked or crowded teeth: Overlapping teeth create tight spaces where plaque builds up and floss can’t easily reach.
- Mouth breathing: Breathing through your mouth dries out your gums, reducing the protective effect of saliva.
- Age: Gingivitis prevalence increases with age, partly due to cumulative plaque exposure and partly due to changes in immune function.
- Stress: Chronic stress impairs your immune response, making it harder for your body to keep oral bacteria in check.
- Poor nutrition overall: Beyond vitamin C, a diet low in essential nutrients limits your body’s ability to repair gum tissue and fight infection.
What Gingivitis Feels Like
Gingivitis is often painless in its early stages, which is part of why it goes unnoticed. The most common sign is gums that bleed when you brush or floss. Healthy gums are pale pink and firm; gingivitis makes them red, puffy, and soft. You might notice a persistent bad taste in your mouth or bad breath that doesn’t go away after brushing. Your gums may look like they’ve pulled slightly away from your teeth, and the tissue between teeth can appear rounded or swollen instead of forming a tight, pointed triangle.
The good news is that gingivitis is fully reversible. Unlike more advanced periodontal disease, no bone or tissue has been permanently destroyed at this stage. Consistent daily brushing (twice a day, for two minutes), daily flossing, and professional cleanings can resolve the inflammation within a few weeks for most people. If you have additional risk factors like diabetes, pregnancy, or a medication that affects your gums, you may need more frequent dental visits to keep things under control.