Dental Plaque - A sticky, colorless film of bacteria that forms on teeth. - Disadvantage: If not removed, plaque can lead to tooth decay and gum disease. Calculus - Hardened plaque that forms when plaque minerals in saliva calcify. - Disadvantage: Cannot be removed by brushing; can irritate gums and lead to gum disease. Tartar - Another term for calculus; hardened plaque. - Disadvantage: Can cause discoloration of teeth, bad breath, and more serious dental issues if not treated. Remember to brush and floss daily to prevent these dental issues!