Having poor oral hygiene can lead to gingivitis (gum inflammation), which can progress to periodontitis (loss of soft tissue and bone structure which support teeth) if left untreated. Periodontitis is a serious medical condition that can lead to tooth loss. 

Having poor oral health can also negatively impact your overall health due to bacteria from your gums entering your bloodstream. These bacteria can then travel to your organs and start new infections that spread throughout your body.