Periodontal disease is caused by a buildup of bacterial plaque that triggers your body’s inflammatory response, which then damages the gums and bone supporting your teeth. Over a billion people worldwide are affected by its severe form. But plaque alone doesn’t tell the whole story. Genetics, smoking, hormonal shifts, certain medications, and nutritional gaps all influence whether mild gum inflammation progresses into serious tissue and bone destruction.
How Plaque Becomes Destructive
Your mouth hosts hundreds of bacterial species that naturally form a sticky film called plaque on your teeth. In a healthy mouth, these microbes exist in balance. The problem starts when plaque accumulates and that balance tips into what’s called dysbiosis: the bacterial community shifts in composition and behavior, favoring species that provoke inflammation.
Your immune system responds to this shift by sending inflammatory cells to fight the bacteria. Ironically, this defense response is what does the most damage. The sustained inflammation breaks down the soft tissue of your gums first, then works deeper to destroy the bone that holds your teeth in place. So periodontal disease isn’t simply an infection. It’s your own immune system overreacting to a bacterial imbalance and destroying healthy tissue in the process.
The Bacteria That Do the Most Harm
Not all mouth bacteria are equal players. Three species in particular, known collectively as the “red complex,” are responsible for the most severe forms of periodontal disease. These bacteria work together synergistically to destroy both soft tissue and the bone underneath. Left untreated, this destruction leads to tooth loss.
One of these species is especially effective because it has a specialized outer layer that helps it stick to gum cells and suppress your immune response at the same time. This combination of clinging tightly to tissue while evading your defenses makes it a primary driver of periodontitis. These bacteria also produce toxins that can enter the bloodstream, which is why periodontal disease has been linked to cardiovascular problems and respiratory infections.
Genetics Account for About a Third of Your Risk
Roughly one-third of the overall risk for periodontitis comes from your genes. Specific genetic variations affect how your immune system produces inflammatory signals. People who carry certain variants in genes controlling inflammation tend to mount a stronger, more destructive immune response to the same amount of plaque bacteria. Studies in European populations found that key inflammatory gene combinations increase periodontitis severity, with risk increases of about 34 to 35 percent compared to people without those variants.
Other genetic markers tied to innate immunity and the integrity of your oral lining have also been linked to periodontitis susceptibility. This genetic component helps explain why some people with relatively little plaque develop aggressive gum disease, while others with poor oral hygiene never progress beyond mild gingivitis. You can’t change your genetic risk, but knowing you have a family history of gum disease is a reason to be more vigilant about the factors you can control.
Smoking Raises Your Risk by 85 Percent
Smoking is the single most impactful modifiable risk factor. A large meta-analysis found that smokers have an 85 percent higher risk of developing periodontitis compared to non-smokers. Smoking impairs blood flow to the gums, weakens the local immune response, and slows healing after treatment. It also masks early warning signs: smokers often have less visible bleeding from their gums, which can delay diagnosis.
Population-level data suggests that if smoking were eliminated entirely, periodontitis cases would drop by about 14 percent. Even smoking fewer than 10 cigarettes a day is enough to accelerate the rate of bone loss and reduce how well standard periodontal treatment works.
How Hormones Affect Your Gums
Fluctuations in estrogen and progesterone directly influence gum tissue, making certain life stages higher-risk periods for periodontal problems. During puberty, girls frequently develop exaggerated gum inflammation that can occur even without significant plaque buildup. The hormonal surge itself sensitizes gum tissue to bacteria that would normally cause a milder reaction.
Pregnancy brings another spike. Rising hormone levels increase gingival inflammation and can cause temporary tooth mobility. This is common enough that “pregnancy gingivitis” is a recognized condition, typically peaking in the second trimester.
Menopause creates a different set of problems. The drop in sex hormones contributes to dry mouth, changes in the bacterial composition of saliva, and accelerated bone loss in the jaw. All three of these changes worsen existing periodontal disease and make new disease more likely to develop.
Medications That Cause Gum Overgrowth
Certain prescription drugs can change the physical structure of your gums, making them thicker and more swollen. This overgrowth creates deeper pockets between the gums and teeth where bacteria thrive, setting the stage for periodontal disease. Three main drug categories are responsible:
- Seizure medications: Drugs used to control epilepsy and other seizure disorders are the most well-known culprits. Several types within this class can trigger gum overgrowth.
- Blood pressure medications: A specific class of drugs that work by relaxing blood vessel walls (calcium channel blockers) can cause gum tissue to enlarge. Multiple drugs in this category carry this side effect.
- Immune-suppressing drugs: Medications prescribed after organ transplants to prevent rejection are also linked to gum overgrowth.
If you take any of these medications and notice your gums becoming puffy or growing over your teeth, that’s worth bringing up at your next dental visit. Meticulous oral hygiene becomes especially important while on these drugs.
Vitamin D and Bone Loss in the Jaw
Vitamin D plays a direct role in maintaining the bone that supports your teeth. It regulates calcium balance, supports bone remodeling, and helps control the inflammatory signals that drive periodontal destruction. Receptors for vitamin D are found throughout your oral tissues, including gum cells, connective tissue cells, and immune cells in the gums.
When vitamin D levels are low, several things go wrong at once. Your body produces more inflammatory chemicals, generates fewer natural antimicrobial compounds, and loses its ability to properly regulate the cells that break down bone. The result is faster periodontal tissue breakdown and impaired healing. Vitamin D insufficiency has also been associated with poor wound healing in the gums, which matters both for disease progression and recovery after treatment.
How Severity Is Measured
Dentists classify periodontal disease on a four-stage scale based on how much damage has already occurred. In Stage I, there’s minimal bone loss and shallow pockets between the gums and teeth. Stage II involves slightly deeper pockets and moderate bone loss, but no teeth have been lost yet. By Stage III, bone loss extends deeper along the tooth roots, pockets are 6 millimeters or more, and up to four teeth may have been lost. Stage IV means extensive destruction: five or more teeth lost, significant bone damage, teeth shifting or drifting, and difficulty chewing.
Alongside staging, clinicians also grade the disease by how fast it’s progressing. Slow progression (Grade A) means no measurable bone loss over five years. Moderate progression (Grade B) means less than 2 millimeters of loss over five years. Rapid progression (Grade C) means 2 millimeters or more of bone lost in that same period. Smoking status and blood sugar control are factored into grading because they reliably predict how quickly the disease will advance. Someone with uncontrolled diabetes or a heavy smoking habit will almost always be graded higher, reflecting the expectation that their disease will move faster and respond less well to treatment.