Gingivitis develops when bacterial plaque builds up along and beneath your gumline, triggering inflammation. About 80% of adults worldwide deal with it at some point, making it one of the most common health conditions on the planet. The good news: it’s the earliest stage of gum disease and fully reversible with the right response.
Plaque Buildup Is the Primary Cause
Your mouth naturally contains hundreds of bacterial species. When you eat, bacteria feed on sugars and starches left on your teeth, forming a sticky, colorless film called plaque. If plaque isn’t removed within about 24 to 48 hours, it starts to harden into tarite (calculus) at the gumline. Tartar can’t be brushed away at home and creates a protective shield for bacteria to thrive underneath.
As bacteria colonize the space between your teeth and gums, your immune system responds with inflammation. That’s gingivitis: red, swollen, tender gums that bleed when you brush or floss. Certain anaerobic bacteria, species that thrive in low-oxygen pockets beneath the gumline, are especially aggressive drivers of this process. The longer plaque and tartar sit undisturbed, the more irritated and inflamed the tissue becomes.
So the simplest answer to “how do you get gingivitis” is: not removing plaque often enough or thoroughly enough. Skipping flossing, rushing through brushing, or missing dental cleanings all give bacteria the time they need to cause trouble.
Smoking and Tobacco Use
Smoking is one of the strongest risk factors for gum disease. Tobacco weakens your immune system, making it harder for your body to fight off the bacterial infection once it starts. It also impairs blood flow to the gums, which slows healing and makes existing damage worse. Perhaps most deceptively, smoking can reduce gum bleeding, which means you might not notice the early warning signs of gingivitis until the disease has progressed further. People who smoke are significantly more likely to develop gum disease than nonsmokers, and they tend to respond less well to treatment.
Hormonal Changes in Women
Shifts in estrogen and progesterone affect how your body responds to plaque. During puberty, menstruation, pregnancy, and menopause, rising hormone levels increase blood flow to the gums and amplify the inflammatory response to even small amounts of bacterial buildup. The result is gums that become red, swollen, and bleed more easily, sometimes even with consistent brushing habits.
Pregnancy gingivitis is particularly common. The hormonal surge doesn’t cause plaque to form, but it dramatically changes how the gum tissue reacts to plaque that’s already there. Women who had perfectly healthy gums before pregnancy can develop noticeable inflammation during the second or third trimester. This typically resolves after delivery, but it still requires attention to prevent progression.
Diabetes and Blood Sugar
High blood sugar creates a favorable environment for gingivitis in two ways. First, elevated glucose levels increase the amount of sugar in your saliva, which feeds bacterial growth and accelerates plaque formation. Second, diabetes impairs your body’s ability to fight infections generally, including infections in the gums. Over time, this combination makes people with poorly controlled diabetes significantly more susceptible to gum disease, and gum disease in turn can make blood sugar harder to control, creating a cycle that reinforces itself.
Low Vitamin C Levels
Vitamin C plays a key role in maintaining the connective tissue in your gums. A large analysis of 15 studies covering over 1,100 people, combined with CDC survey data from more than 8,200 participants, found that even modestly low vitamin C levels in the bloodstream were associated with increased gum bleeding. You don’t need to be severely deficient to see effects. While full-blown scurvy (caused by extreme vitamin C deficiency) is rare, slightly low intake can weaken gum tissue enough to worsen or mimic gingivitis symptoms.
Certain Medications
Some prescription medications cause gum tissue to overgrow, creating deeper pockets where bacteria can hide and making plaque harder to remove. Three classes of drugs are most commonly involved: seizure medications (particularly phenytoin), blood pressure medications known as calcium channel blockers (like nifedipine and amlodipine), and immunosuppressant drugs used after organ transplants. If you take any of these and notice your gums looking puffy or growing over your teeth, that overgrowth itself increases your risk of developing gingivitis on top of it.
Other Contributing Factors
Crooked or crowded teeth create tight spaces that are difficult to clean, giving plaque more places to accumulate. Older dental work, like poorly fitting crowns or bridges, can have the same effect. Breathing through your mouth, especially during sleep, dries out gum tissue and reduces the protective effect of saliva, which normally helps wash bacteria away. Nutritional deficiencies beyond vitamin C, chronic stress, and a family history of gum disease can also raise your risk.
Age plays a role too. While gingivitis can develop at any age, the likelihood increases over time simply because the cumulative effects of plaque exposure, medication use, and other health conditions add up.
What Gingivitis Feels Like
The earliest sign is usually bleeding when you brush or floss, particularly if you haven’t flossed in a while. Healthy gums are pale pink and firm. With gingivitis, they turn darker red, feel puffy or tender, and may pull slightly away from the teeth. Bad breath that doesn’t go away after brushing is another common signal. Some people feel no pain at all, which is why gingivitis often goes unnoticed until a dental visit.
How Gingivitis Reverses
Unlike more advanced gum disease, gingivitis hasn’t damaged the bone or connective tissue holding your teeth in place. That means it can be completely reversed. A professional dental cleaning removes tartar that traps bacteria, and from there, consistent brushing twice daily and daily flossing is usually enough. The Mayo Clinic notes that healthy gum tissue can return within days to weeks of starting proper care.
If left untreated, gingivitis can progress to periodontitis, a more serious form of gum disease where the inner layer of gum and bone pull away from the teeth, forming infected pockets. At that stage, the damage isn’t reversible and treatment becomes more involved. The gap between gingivitis and periodontitis is the reason early action matters so much.