Periodontitis. When gingivitis is not treated, it can advance to âperiodontitisâ (which means âinflammation around the toothâ). In periodontitis, gums pull away from the teeth and form spaces (called âpocketsâ) that become infected.The bodyâs immune system fights the bacteria as the plaque spreads and grows below the gum line. Medications. 2  There are hundreds of prescription and over the counter medications that can reduce the flow of saliva, which has a protective effect on the mouth. 3  Without enough saliva, the mouth is vulnerable to infections such as gum disease.