Dental surgery is any of a number of medical procedures that involve artificially modifying dentition; in other words, surgery of the teeth, gums and jaw bones. More frequent than usual cleaning and examination may be necessary during the treatment of many different dental/oral disorders or due to recent surgical procedures such as dental implants. The American Dental Association (ADA) stresses that the frequency of dental visits necessary is dependent upon the needs of each individual with some able to go once or twice a year and others needing to go more often. This may include yearly, select dental X-rays. See also dental plaque identification procedure and removal. Dentists inject anesthetic to block sensory transmission by the alveolar nerves. The superior alveolar nerves are not usually anesthetized directly because they are difficult to approach with a needle. For this reason, the maxillary teeth are usually anesthetized locally by inserting the needle beneath the oral mucosa surrounding the teeth. The inferior alveolar nerve is probably anesthetized more often than any other nerve in the body. To anesthetize this nerve, the dentist inserts the needle somewhat beyond the patient’s last molar. Dentistry, also known as dental medicine and oral medicine, is a branch of medicine that consists of the study, diagnosis, prevention, and treatment of diseases, disorders, and conditions of the oral cavity, commonly in the dentition but also the oral mucosa, and of adjacent and related structures and tissues, particularly in the maxillofacial (jaw and facial) area.[1] Although primarily associated with teeth among the general public, the field of dentistry or dental medicine is not limited to teeth but includes other aspects of the craniofacial complex including the temporomandibular joint and other supporting, muscular, lymphatic, nervous, vascular, and anatomical structures. Dentistry is often also understood to subsume the now largely defunct medical specialty of stomatology (the study of the mouth and its disorders and diseases) for which reason the two terms are used interchangeably in certain regions.[where?] Dental treatments are carried out by a dental team, which often consists of a dentist and dental auxiliaries (dental assistants, dental hygienists, dental technicians, as well as dental therapists). Most dentists either work in private practices (primary care), dental hospitals or (secondary care) institutions (prisons, armed forces bases, etc.). The history of dentistry is almost as ancient as the history of humanity and civilization with the earliest evidence dating from 7000 BC to 5500 BC.[2] Skeletal remains from Mehgarh (now in Pakistan) dated to that time show evidence of teeth having been drilled with flint tools to remove decay, a method found to be "surprisingly effective".[2] Dentistry is thought to have been the first specialization in medicine.[3] The modern movement of evidence-based dentistry calls for the use of high-quality scientific evidence to guide decision-making.