A branch of medicine that involves diagnosis, revention, and treatment of any disease concern about teeth, oral cavity, and associated structures is called Dentistry.Dentistry is the practical application of knowledge of dental science (the science of placement, arrangement, function of teeth and their supporting bones and soft tissues) to human beings. A dentist is a professional practitioner of dentistry. the oral cavity, the maxillofacial region, and its associated structures as it relates to human beings. While the work of dentists is often surgical in nature, dentists can and do treat many diseases of the oral cavity and face chemotherapeutically .