Malocclusion, Angle Class II: Malocclusion in which the mandible is posterior to the maxilla as reflected by the relationship of the first permanent molar (distoclusion).Malocclusion: Such malposition and contact of the maxillary and mandibular teeth as to interfere with the highest efficiency during the excursive movements of the jaw that are essential for mastication. (Jablonski, Illustrated Dictionary of Dentistry, 1982)Malocclusion, Angle Class I: Malocclusion in which the mandible and maxilla are anteroposteriorly normal as reflected by the relationship of the first permanent molar (i.e., in neutroclusion), but in which individual teeth are abnormally related to each other.Serial Extraction: The selective extraction of deciduous teeth during the stage of mixed dentition in accordance with the shedding and eruption of the teeth. It is done over an extended period to allow autonomous adjustment to relieve crowding of the dental arches during the eruption of the lateral incisors, canines, and premolars, eventually involving the extraction of the first premolar teeth. (Dorland, 28th ed)Malocclusion, Angle Class III: Malocclusion in which the mandible is anterior to the maxilla as reflected by the first relationship of the first permanent molar (mesioclusion).Cephalometry: The measurement of the dimensions of the HEAD.Mouth Breathing: Abnormal breathing through the mouth, usually associated with obstructive disorders of the nasal passages.Maxilla: One of a pair of irregularly shaped bones that form the upper jaw. A maxillary bone provides tooth sockets for the superior teeth, forms part of the ORBIT, and contains the MAXILLARY SINUS.Overbite: A malocclusion in which maxillary incisor and canine teeth project over the mandiblar teeth excessively. The overlap is measured perpendicular to the occlusal plane and is also called vertical overlap. When the overlap is measured parallel to the occlusal plane it is referred to as overjet.Open Bite: A condition in which certain opposing teeth fail to establish occlusal contact when the jaws are closed.Orthodontics, Corrective: The phase of orthodontics concerned with the correction of malocclusion with proper appliances and prevention of its sequelae (Jablonski's Illus. Dictionary of Dentistry).Vertical Dimension: The length of the face determined by the distance of separation of jaws. Occlusal vertical dimension (OVD or VDO) or contact vertical dimension is the lower face height with the teeth in centric occlusion. Rest vertical dimension (VDR) is the lower face height measured from a chin point to a point just below the nose, with the mandible in rest position. (From Jablonski, Dictionary of Dentistry, 1992, p250)Maxillofacial Development: The process of growth and differentiation of the jaws and face.Extraoral Traction Appliances: Extraoral devices for applying force to the dentition in order to avoid some of the problems in anchorage control met with in intermaxillary traction and to apply force in directions not otherwise possible.Diastema: An abnormal opening or fissure between two adjacent teeth.Incisor: Any of the eight frontal teeth (four maxillary and four mandibular) having a sharp incisal edge for cutting food and a single root, which occurs in man both as a deciduous and a permanent tooth. (Jablonski, Dictionary of Dentistry, 1992, p820)Jaw Relation Record: A registration of any positional relationship of the mandible in reference to the maxillae. These records may be any of the many vertical, horizontal, or orientation relations. (Jablonski, Illustrated Dictionary of Dentistry)Mandible: The largest and strongest bone of the FACE constituting the lower jaw. It supports the lower teeth.Histocompatibility Antigens Class II: Large, transmembrane, non-covalently linked glycoproteins (alpha and beta). Both chains can be polymorphic although there is more structural variation in the beta chains. The class II antigens in humans are called HLA-D ANTIGENS and are coded by a gene on chromosome 6. In mice, two genes named IA and IE on chromosome 17 code for the H-2 antigens. The antigens are found on B-lymphocytes, macrophages, epidermal cells, and sperm and are thought to mediate the competence of and cellular cooperation in the immune response. The term IA antigens used to refer only to the proteins encoded by the IA genes in the mouse, but is now used as a generic term for any class II histocompatibility antigen.Dental Arch: The curve formed by the row of TEETH in their normal position in the JAW. The inferior dental arch is formed by the mandibular teeth, and the superior dental arch by the maxillary teeth.Dentition, Mixed: The complement of teeth in the jaws after the eruption of some of the permanent teeth but before all the deciduous teeth are absent. (Boucher's Clinical Dental Terminology, 4th ed)Orthodontic Appliances, Functional: Loose, usually removable intra-oral devices which alter the muscle forces against the teeth and craniofacial skeleton. These are dynamic appliances which depend on altered neuromuscular action to effect bony growth and occlusal development. They are usually used in mixed dentition to treat pediatric malocclusions. (ADA, 1992)Activator Appliances: Loose-fitting removable orthodontic appliances which redirect the pressures of the facial and masticatory muscles onto the teeth and their supporting structures to produce improvements in tooth arrangements and occlusal relations.Tooth Movement: Orthodontic techniques used to correct the malposition of a single tooth.Dental Models: Presentation devices used for patient education and technique training in dentistry.Molar: The most posterior teeth on either side of the jaw, totaling eight in the deciduous dentition (2 on each side, upper and lower), and usually 12 in the permanent dentition (three on each side, upper and lower). They are grinding teeth, having large crowns and broad chewing surfaces. (Jablonski, Dictionary of Dentistry, 1992, p821)Orthodontic Anchorage Procedures: Attachment of orthodontic devices and materials to the MOUTH area for support and to provide a counterforce to orthodontic forces.Dental Occlusion: The relationship of all the components of the masticatory system in normal function. It has special reference to the position and contact of the maxillary and mandibular teeth for the highest efficiency during the excursive movements of the jaw that are essential for mastication. (From Jablonski, Dictionary of Dentistry, 1992, p556, p472)Orthodontics, Interceptive: Recognition and elimination of potential irregularities and malpositions in the developing dentofacial complex.Orthodontic Appliance Design: The planning, calculation, and creation of an apparatus for the purpose of correcting the placement or straightening of teeth.Tooth Mobility: Horizontal and, to a lesser degree, axial movement of a tooth in response to normal forces, as in occlusion. It refers also to the movability of a tooth resulting from loss of all or a portion of its attachment and supportive apparatus, as seen in periodontitis, occlusal trauma, and periodontosis. (From Jablonski, Dictionary of Dentistry, 1992, p507 & Boucher's Clinical Dental Terminology, 4th ed, p313)Genes, MHC Class II: Genetic loci in the vertebrate major histocompatibility complex that encode polymorphic products which control the immune response to specific antigens. The genes are found in the HLA-D region in humans and in the I region in mice.Fingersucking: Sucking of the finger. This is one of the most common manipulations of the body found in young children.Cuspid: The third tooth to the left and to the right of the midline of either jaw, situated between the second INCISOR and the premolar teeth (BICUSPID). (Jablonski, Dictionary of Dentistry, 1992, p817)Retrognathia: A physical misalignment of the upper (maxilla) and lower (mandibular) jaw bones in which either or both recede relative to the frontal plane of the forehead.Esthetics, Dental: Skills, techniques, standards, and principles used to improve the art and symmetry of the teeth and face to improve the appearance as well as the function of the teeth, mouth, and face. (From Boucher's Clinical Dental Terminology, 4th ed, p108)Orthodontics: A dental specialty concerned with the prevention and correction of dental and oral anomalies (malocclusion).Chin: The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve.Palatal Expansion Technique: An orthodontic method used for correcting narrow or collapsed maxillary arches and functional cross-bite. (From Jablonski's Dictionary of Dentistry),Orthodontic Appliances: Devices used for influencing tooth position. Orthodontic appliances may be classified as fixed or removable, active or retaining, and intraoral or extraoral. (Boucher's Clinical Dental Terminology, 4th ed, p19)Dental Occlusion, Centric: Contact between opposing teeth during a person's habitual bite.Tongue Habits: Acquired responses regularly manifested by tongue movement or positioning.Dental Occlusion, Traumatic: An occlusion resulting in overstrain and injury to teeth, periodontal tissue, or other oral structures.Sucking Behavior: Any suction exerted by the mouth; response of the mammalian infant to draw milk from the breast. Includes sucking on inanimate objects. Not to be used for thumb sucking, which is indexed under fingersucking.Index of Orthodontic Treatment Need: A dental health survey developed to evaluate a patient's orthodontic treatment need and priority for orthodontic care. The index is based on an assessment of degree of MALOCCLUSION and the potential aesthetic and dental health benefit of the treatment under consideration.Orthodontic Appliances, Removable: Dental devices such as RETAINERS, ORTHODONTIC used to improve gaps in teeth and structure of the jaws. These devices can be removed and reinserted at will.Lip: Either of the two fleshy, full-blooded margins of the mouth.Facial Bones: The facial skeleton, consisting of bones situated between the cranial base and the mandibular region. While some consider the facial bones to comprise the hyoid (HYOID BONE), palatine (HARD PALATE), and zygomatic (ZYGOMA) bones, MANDIBLE, and MAXILLA, others include also the lacrimal and nasal bones, inferior nasal concha, and vomer but exclude the hyoid bone. (Jablonski, Dictionary of Dentistry, 1992, p113)Prognathism: A condition marked by abnormal protrusion of the mandible. (Dorland, 27th ed)Myofunctional Therapy: Training or retraining of the buccal, facial, labial, and lingual musculature in toothless conditions; DEGLUTITION DISORDERS; TEMPOROMANDIBULAR JOINT DISORDERS; MALOCCLUSION; and ARTICULATION DISORDERS.Maxillofacial Abnormalities: Congenital structural deformities, malformations, or other abnormalities of the maxilla and face or facial bones.Skull Base: The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface.Sella Turcica: A bony prominence situated on the upper surface of the body of the sphenoid bone. It houses the PITUITARY GLAND.Facial Muscles: Muscles of facial expression or mimetic muscles that include the numerous muscles supplied by the facial nerve that are attached to and move the skin of the face. (From Stedman, 25th ed)Facial Asymmetry: Congenital or acquired asymmetry of the face.Bicuspid: One of the eight permanent teeth, two on either side in each jaw, between the canines (CUSPID) and the molars (MOLAR), serving for grinding and crushing food. The upper have two cusps (bicuspid) but the lower have one to three. (Jablonski, Dictionary of Dentistry, 1992, p822)Nasal Bone: Either one of the two small elongated rectangular bones that together form the bridge of the nose.Mandibular Condyle: The posterior process on the ramus of the mandible composed of two parts: a superior part, the articular portion, and an inferior part, the condylar neck.Tooth Abnormalities: Congenital absence of or defects in structures of the teeth.HLA-D Antigens: Human immune-response or Class II antigens found mainly, but not exclusively, on B-lymphocytes and produced from genes of the HLA-D locus. They are extremely polymorphic families of glycopeptides, each consisting of two chains, alpha and beta. This group of antigens includes the -DR, -DQ and -DP designations, of which HLA-DR is most studied; some of these glycoproteins are associated with certain diseases, possibly of immune etiology.Bruxism: A disorder characterized by grinding and clenching of the teeth.Smiling: A facial expression which may denote feelings of pleasure, affection, amusement, etc.Odontometry: Measurement of tooth characteristics.Pacifiers: Devices that babies can suck on when they are not feeding. The extra sucking can be comforting to the babies and pacify them. Pacifiers usually are used as a substitute for the thumb in babies who suck on their thumb or fingers almost constantly.Orthodontic Wires: Wires of various dimensions and grades made of stainless steel or precious metal. They are used in orthodontic treatment.Temporomandibular Joint Disorders: A variety of conditions affecting the anatomic and functional characteristics of the temporomandibular joint. Factors contributing to the complexity of temporomandibular diseases are its relation to dentition and mastication and the symptomatic effects in other areas which account for referred pain to the joint and the difficulties in applying traditional diagnostic procedures to temporomandibular joint pathology where tissue is rarely obtained and x-rays are often inadequate or nonspecific. Common diseases are developmental abnormalities, trauma, subluxation, luxation, arthritis, and neoplasia. (From Thoma's Oral Pathology, 6th ed, pp577-600)Orthognathic Surgical Procedures: Surgery performed to repair or correct the skeletal anomalies of the jaw and its associated dental and facial structures (e.g. CLEFT PALATE).Tooth Eruption: The emergence of a tooth from within its follicle in the ALVEOLAR PROCESS of the MAXILLA or MANDIBLE into the ORAL CAVITY. (Boucher's Clinical Dental Terminology, 4th ed)Peer Review, Health Care: The concurrent or retrospective review by practicing physicians or other health professionals of the quality and efficiency of patient care practices or services ordered or performed by other physicians or other health professionals (From The Facts On File Dictionary of Health Care Management, 1988).Centric Relation: The location of the maxillary and the mandibular condyles when they are in their most posterior and superior positions in their fossae of the temporomandibular joint.HLA-DR Antigens: A subclass of HLA-D antigens that consist of alpha and beta chains. The inheritance of HLA-DR antigens differs from that of the HLA-DQ ANTIGENS and HLA-DP ANTIGENS.Masseter Muscle: A masticatory muscle whose action is closing the jaws.Mastication: The act and process of chewing and grinding food in the mouth.Orthodontic Retainers: Orthodontic appliances, fixed or removable, used to maintain teeth in corrected positions during the period of functional adaptation following corrective treatment. These appliances are also used to maintain the positions of the teeth and jaws gained by orthodontic procedures. (From Zwemer, Boucher's Clinical Dental Terminology, 4th ed, p263)Tooth: One of a set of bone-like structures in the mouth used for biting and chewing.Dental Health Surveys: A systematic collection of factual data pertaining to dental or oral health and disease in a human population within a given geographic area.Mandibular Advancement: Moving a retruded mandible forward to a normal position. It is commonly performed for malocclusion and retrognathia. (From Jablonski's Dictionary of Dentistry, 1992)Osteotomy, Le Fort: Transverse sectioning and repositioning of the maxilla. There are three types: Le Fort I osteotomy for maxillary advancement or the treatment of maxillary fractures; Le Fort II osteotomy for the treatment of maxillary fractures; Le Fort III osteotomy for the treatment of maxillary fractures with fracture of one or more facial bones. Le Fort III is often used also to correct craniofacial dysostosis and related facial abnormalities. (From Dorland, 28th ed, p1203 & p662)Histocompatibility Antigens Class I: Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.Tooth, Deciduous: The teeth of the first dentition, which are shed and replaced by the permanent teeth.