You can develop an infection when plaque extends below the gum line. Left unchecked, gingivitis can cause the gums to separate from the teeth. This can cause injury to the soft tissue and bone supporting the teeth. The tooth may become loose and unstable.If infection progresses, you may ultimately lose your tooth or need a dentist to remove it.ood can get trapped in this space and cause a gum infection or gingivitis. Plaque is a thin film of bacteria. It constantly forms on the surface of your teeth. As plaque advances, it hardens and becomes tartar.