uberwulf n. An instrument which was formerly used for the extraction of teeth. It was a development of the *pelican with an elevator instead of a bolster. The tooth was extracted in an arc instead of using an oblique force required by the earlier pelicans, a technique which was considered to be less successful. It was superseded by the *tooth key in the early 18th century.
ugly duckling stage A stage of dental development, usually between the ages of 7 and 12 years, preceding the eruption of the permanent canines when the upper central and lateral incisors are tipped laterally due to the crowding created by the unerupted canines, to produce a midline space (median diastema). The midline space is normally transitory and the incisors usually assume normal alignment when the upper canines erupt into position.
ulalgia n. Pain in the gingival tissues.
ulatrophy n. *Atrophy of the gingival tissue associated with recession and exposure of the root portion of the tooth. Afunctional ulatrophy is gingival atrophy occurring in a *congenital *malocclusion. Atrophic (*ischaemic) ulatrophy describes gingival atrophy due to a deficient blood supply to the gingival tissues. Traumatic ulatrophy is gingival atrophy due to trauma to the gingival tissues.
ulcer n. A break in the skin or *mucosa so that the underlying connective tissue is exposed. The margins are inflamed and the surface is covered by slough. See also ORAL ULCERATION; APHTHOUS ULCER.
ulcerative colitis n. A chronic inflammatory disease of the mucosa and submucosa of the colon manifested clinically by pain, diarrhoea, and rectal bleeding. Oral symptoms may include necrotic mucosal lesions indistinguishable from *aphthous ulcers. The condition is closely related to *Crohn’s disease.
MedicineNet factsheet on the symptoms, causes, and treatment of ulcerative colitis.
ulitis n. An alternative name for *gingivitis.
ultimate strength n. See STRENGTH.
ultrasonic adj. Describing sounds with frequencies above 20,000 Hz and therefore beyond the range of human hearing. An ultrasonic cleaner is a piece of equipment that creates high-frequency vibrations in a fluid-filled container; it is used to remove debris and particulate matter from dental instruments and appliances by a process of *cavitation. The fluid is usually an enzymatic *detergent designed to digest biological material. This method of cleaning is suitable for stainless steel instruments but is not appropriate for plastic items. Ultrasonic scaler See SCALER. Ultrasonic tips may be used to locate fine root canals when undertaking endodontic therapy.