halitosis – chronic bad breath, generally caused by an oral or gastrointestinal disorder

hematoma – blood swelling beneath the surface of the skin, gums, or other tissue

hygienist – a dental professional who is trained and certified to perform dental cleanings, scaling and root planning, and other functions, provides patient education, and may administer local anesthetic or nitrous oxide

hyperplasia – abnormal increase in cell growth leading to enlargement of tissue