One form of periodontal disease is gingivitis. This mild form of periodontal disease is fairly common especially among teens, pregnant women and older adults. In most cases, gingivitis is reversible. However, if gingivitis is left untreated, it can lead to the deterioration of your gums and eventually your teeth.
The main cause of gingivitis is plaque. The National Institutes of Health (NIH) states ʺPlaque is a sticky material made of bacteria, mucus, and food debris that develops on the exposed parts of the teeth.ʺ
Plaque is generally caused by poor dental hygiene. And, the main cause of tooth decay is plaque because plaque turns into tartar. According to CNN, ʺPlaque requires daily removal because it re-forms quickly, usually within 24 hours. ʺ Also, within 48-72 hours plaque can harden and turn into tartar. These two enemies of the mouth cause the symptoms of gingivitis.
https://www.empowher.com/gingivitis/content/gingivitis-causes-symptoms-risks-and-treatment