Cardiovascular diseases:
Epidemiological studies have shown that individuals with periodontal disease are more susceptible to developing atherosclerosis, coronary heart disease, and stroke. It is assumed that bacteria from the oral cavity can enter the bloodstream and contribute to the formation of atherosclerotic plaques. In addition, systemic inflammation resulting from periodontal disease increases inflammatory markers such as C-reactive protein (CRP), further contributing to the development of cardiovascular disease.

Diabetes:
There is a bidirectional relationship between periodontal disease and diabetes. People with poorly controlled diabetes are more prone to developing periodontal disease due to a reduced ability of the immune system to fight infection. At the same time, chronic inflammation and periodontal disease can impair control of blood glucose levels, leading to more difficult-to-control diabetes.

Osteoporosis:
There is evidence that postmenopausal women who have osteoporosis are at increased risk of alveolar bone loss, which may contribute to periodontal disease. Osteoporosis affects bone density throughout the body, including the dental ridge, leading to increased susceptibility to periodontal destruction.

Oncological diseases:
In recent years, research has shown that periodontal disease is associated with an increased risk of various types of cancer, including cancer of the mouth, esophagus, pancreas, and bowel (colorectal cancer). The chronic inflammation that characterizes periodontal disease can create an environment that encourages the development of cancer cells. Studies have shown that people with advanced periodontal disease are more likely to develop these types of cancer. Also, some bacteria associated with periodontal disease, such as Fusobacterium nucleatum, are also associated with bowel cancer. A 2022 review study focuses on the link between the oral microbiome, periodontal disease and the development of colorectal cancer. Research has shown that bacteria associated with periodontal disease can contribute to inflammation and changes in the gut microbiota, increasing the risk of developing colorectal cancer.

Neurological diseases:
Research in recent years has also shown a link between periodontal disease and an increased risk of developing neurological diseases, including Alzheimer’s disease. One of the key bacteria associated with periodontal disease, Porphyromonas gingivalis, produces proteolytic enzymes called gingipains. Gingipains can pass into brain tissue, where they cause inflammation and contribute to the formation of the amyloid plaques that characterize Alzheimer’s disease. In addition, gingipains promote neurodegenerative processes, which may increase the risk of developing other neurological diseases. A 2019 study investigates the presence of Porphyromonas gingivalis and its secretions (gingipains) in the brains of Alzheimer’s patients. The results showed that the presence of these bacteria and their enzymes is associated with the development of neurodegenerative changes, which indicates a possible causal influence of periodontal disease on the development of Alzheimer’s disease. The study also opens up the possibility of developing new therapies that could prevent or slow the progression of neurological diseases by inhibiting the activity of gingipains.