A person may not know that he or she has bad breath. This phenomenon is because odor-detecting cells in the nose eventually become accustomed to the constant flow of bad smells from the mouth.
Poor Dental hygiene: Teeth are coated with film, or plaque, food debris trapped between teeth, pale or swollen gums.
Infections in the mouth; Gums may be red, swollen, and bleed easily, especially after brushing or flossing; pus may drain from between teeth: a pocket of pus ( access) at the base of the tooth; loose teeth or a change in "fit" of a denture. Painful open sores on the tongue or gums.
Dr. James L. Johnson