Diastema: An abnormal opening or fissure between two adjacent teeth.Quackery: The fraudulent misrepresentation of the diagnosis and treatment of disease.Obsessive Behavior: Persistent, unwanted idea or impulse which is considered normal when it does not markedly interfere with mental processes or emotional adjustment.Tooth Germ: The collective tissues from which an entire tooth is formed, including the DENTAL SAC; ENAMEL ORGAN; and DENTAL PAPILLA. (From Jablonski, Dictionary of Dentistry, 1992)Tooth: One of a set of bone-like structures in the mouth used for biting and chewing.Labial FrenumSmiling: A facial expression which may denote feelings of pleasure, affection, amusement, etc.Dental Pulp Necrosis: Death of pulp tissue with or without bacterial invasion. When the necrosis is due to ischemia with superimposed bacterial infection, it is referred to as pulp gangrene. When the necrosis is non-bacterial in origin, it is called pulp mummification.Orthodontic Space Closure: Therapeutic closure of spaces caused by the extraction of teeth, the congenital absence of teeth, or the excessive space between teeth.Odontogenesis: The process of TOOTH formation. It is divided into several stages including: the dental lamina stage, the bud stage, the cap stage, and the bell stage. Odontogenesis includes the production of tooth enamel (AMELOGENESIS), dentin (DENTINOGENESIS), and dental cementum (CEMENTOGENESIS).Tooth, Supernumerary: An extra tooth, erupted or unerupted, resembling or unlike the other teeth in the group to which it belongs. Its presence may cause malposition of adjacent teeth or prevent their eruption.Root Canal Therapy: A treatment modality in endodontics concerned with the therapy of diseases of the dental pulp. For preparatory procedures, ROOT CANAL PREPARATION is available.