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)Orthodontic Brackets: Small metal or ceramic attachments used to fasten an arch wire. These attachments are soldered or welded to an orthodontic band or cemented directly onto the teeth. Bowles brackets, edgewise brackets, multiphase brackets, ribbon arch brackets, twin-wire brackets, and universal brackets are all types of orthodontic brackets.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.Orthodontic Appliance Design: The planning, calculation, and creation of an apparatus for the purpose of correcting the placement or straightening of teeth.Tooth Movement: Orthodontic techniques used to correct the malposition of a single tooth.Orthodontic Wires: Wires of various dimensions and grades made of stainless steel or precious metal. They are used in orthodontic treatment.Dental Alloys: A mixture of metallic elements or compounds with other metallic or metalloid elements in varying proportions for use in restorative or prosthetic dentistry.Stainless Steel: Stainless steel. A steel containing Ni, Cr, or both. It does not tarnish on exposure and is used in corrosive environments. (Grant & Hack's Chemical Dictionary, 5th 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)Dental Debonding: Techniques used for removal of bonded orthodontic appliances, restorations, or fixed dentures from teeth.Dental Plaque Index: An index which scores the degree of dental plaque accumulation.Root Resorption: Resorption in which cementum or dentin is lost from the root of a tooth owing to cementoclastic or osteoclastic activity in conditions such as trauma of occlusion or neoplasms. (Dorland, 27th ed)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).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)Elastomers: A generic term for all substances having the properties of stretching under tension, high tensile strength, retracting rapidly, and recovering their original dimensions fully. They are generally POLYMERS.Dental Plaque: A film that attaches to teeth, often causing DENTAL CARIES and GINGIVITIS. It is composed of MUCINS, secreted from salivary glands, and microorganisms.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)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.Dental Stress Analysis: The description and measurement of the various factors that produce physical stress upon dental restorations, prostheses, or appliances, materials associated with them, or the natural oral structures.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)Nickel: A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.Dental Bonding: An adhesion procedure for orthodontic attachments, such as plastic DENTAL CROWNS. This process usually includes the application of an adhesive material (DENTAL CEMENTS) and letting it harden in-place by light or chemical curing.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)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)Lip: Either of the two fleshy, full-blooded margins of the mouth.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.Halitosis: An offensive, foul breath odor resulting from a variety of causes such as poor oral hygiene, dental or oral infections, or the ingestion of certain foods.Friction: Surface resistance to the relative motion of one body against the rubbing, sliding, rolling, or flowing of another with which it is in contact.Resin Cements: Dental cements composed either of polymethyl methacrylate or dimethacrylate, produced by mixing an acrylic monomer liquid with acrylic polymers and mineral fillers. The cement is insoluble in water and is thus resistant to fluids in the mouth, but is also irritating to the dental pulp. It is used chiefly as a luting agent for fabricated and temporary restorations. (Jablonski's Dictionary of Dentistry, 1992, p159)Toothbrushing: The act of cleaning teeth with a brush to remove plaque and prevent tooth decay. (From Webster, 3d ed)Alveolar Process: The thickest and spongiest part of the maxilla and mandible hollowed out into deep cavities for the teeth.Shear Strength: The internal resistance of a material to moving some parts of it parallel to a fixed plane, in contrast to stretching (TENSILE STRENGTH) or compression (COMPRESSIVE STRENGTH). Ionic crystals are brittle because, when subjected to shear, ions of the same charge are brought next to each other, which causes repulsion.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).Periodontal Index: A numerical rating scale for classifying the periodontal status of a person or population with a single figure which takes into consideration prevalence as well as severity of the condition. It is based upon probe measurement of periodontal pockets and on gingival tissue status.Tongue: A muscular organ in the mouth that is covered with pink tissue called mucosa, tiny bumps called papillae, and thousands of taste buds. The tongue is anchored to the mouth and is vital for chewing, swallowing, and for speech.Dental Enamel: A hard thin translucent layer of calcified substance which envelops and protects the dentin of the crown of the tooth. It is the hardest substance in the body and is almost entirely composed of calcium salts. Under the microscope, it is composed of thin rods (enamel prisms) held together by cementing substance, and surrounded by an enamel sheath. (From Jablonski, Dictionary of Dentistry, 1992, p286)Ceramics: Products made by baking or firing nonmetallic minerals (clay and similar materials). In making dental restorations or parts of restorations the material is fused porcelain. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Boucher's Clinical Dental Terminology, 4th ed)Materials Testing: The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.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)Adhesives: Substances that cause the adherence of two surfaces. They include glues (properly collagen-derived adhesives), mucilages, sticky pastes, gums, resins, or latex.Social Desirability: A personality trait rendering the individual acceptable in social or interpersonal relations. It is related to social acceptance, social approval, popularity, social status, leadership qualities, or any quality making him a socially desirable companion.Gingivitis: Inflammation of gum tissue (GINGIVA) without loss of connective tissue.Periodontal Ligament: The fibrous CONNECTIVE TISSUE surrounding the TOOTH ROOT, separating it from and attaching it to the alveolar bone (ALVEOLAR PROCESS).Acid Etching, Dental: Preparation of TOOTH surfaces and DENTAL MATERIALS with etching agents, usually phosphoric acid, to roughen the surface to increase adhesion or osteointegration.Gingiva: Oral tissue surrounding and attached to TEETH.Phosphoric Acids: Inorganic derivatives of phosphoric acid (H3PO4). Note that organic derivatives of phosphoric acids are listed under ORGANOPHOSPHATES.Bisphenol A-Glycidyl Methacrylate: The reaction product of bisphenol A and glycidyl methacrylate that undergoes polymerization when exposed to ultraviolet light or mixed with a catalyst. It is used as a bond implant material and as the resin component of dental sealants and composite restorative materials.Equipment Reuse: Further or repeated use of equipment, instruments, devices, or materials. It includes additional use regardless of the original intent of the producer as to disposability or durability. It does not include the repeated use of fluids or solutions.Silanes: Compounds similar to hydrocarbons in which a tetravalent silicon atom replaces the carbon atom. They are very reactive, ignite in air, and form useful derivatives.Streptococcus mutans: A polysaccharide-producing species of STREPTOCOCCUS isolated from human dental plaque.Statistics, Nonparametric: A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)Dental Models: Presentation devices used for patient education and technique training in dentistry.Saliva, Artificial: A solution used for irrigating the mouth in xerostomia and as a substitute for saliva.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)Occlusal Splints: Rigid or flexible appliances that overlay the occlusal surfaces of the teeth. They are used to treat clenching and bruxism and their sequelae, and to provide temporary relief from muscle or temporomandibular joint pain.Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Aluminum Silicates: Any of the numerous types of clay which contain varying proportions of Al2O3 and SiO2. They are made synthetically by heating aluminum fluoride at 1000-2000 degrees C with silica and water vapor. (From Hawley's Condensed Chemical Dictionary, 11th ed)Acrylic ResinsCephalometry: The measurement of the dimensions of the HEAD.Dental Cements: Substances used to bond COMPOSITE RESINS to DENTAL ENAMEL and DENTIN. These bonding or luting agents are used in restorative dentistry, ROOT CANAL THERAPY; PROSTHODONTICS; and ORTHODONTICS.Mandible: The largest and strongest bone of the FACE constituting the lower jaw. It supports the lower teeth.Polycarboxylate Cement: Water-soluble low-molecular-weight polymers of acrylic or methacrylic acid that form solid, insoluble products when mixed with specially prepared ZnO powder. The resulting cement adheres to dental enamel and is also used as a luting agent.Saliva: The clear, viscous fluid secreted by the SALIVARY GLANDS and mucous glands of the mouth. It contains MUCINS, water, organic salts, and ptylin.Palatal Expansion Technique: An orthodontic method used for correcting narrow or collapsed maxillary arches and functional cross-bite. (From Jablonski's Dictionary of Dentistry),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.Hydrofluoric Acid: Hydrofluoric acid. A solution of hydrogen fluoride in water. It is a colorless fuming liquid which can cause painful burns.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.Household Articles: Various material objects and items in the home. It includes temporary or permanent machinery and appliances. It does not include furniture or interior furnishings (FURNITURE see INTERIOR DESIGN AND FURNISHINGS; INTERIOR FURNISHINGS see INTERIOR DESIGN AND FURNISHINGS).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)Dental Occlusion, Centric: Contact between opposing teeth during a person's habitual bite.Aluminum Oxide: An oxide of aluminum, occurring in nature as various minerals such as bauxite, corundum, etc. It is used as an adsorbent, desiccating agent, and catalyst, and in the manufacture of dental cements and refractories.Corrosion: The gradual destruction of a metal or alloy due to oxidation or action of a chemical agent. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Colony Count, Microbial: Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.Titanium: A dark-gray, metallic element of widespread distribution but occurring in small amounts; atomic number, 22; atomic weight, 47.90; symbol, Ti; specific gravity, 4.5; used for fixation of fractures. (Dorland, 28th ed)Adhesiveness: A property of the surface of an object that makes it stick to another surface.Glass Ionomer Cements: A polymer obtained by reacting polyacrylic acid with a special anion-leachable glass (alumino-silicate). The resulting cement is more durable and tougher than others in that the materials comprising the polymer backbone do not leach out.Equipment Failure: Failure of equipment to perform to standard. The failure may be due to defects or improper use.Light-Curing of Dental Adhesives: The hardening or polymerization of bonding agents (DENTAL CEMENTS) via exposure to light.Composite Resins: Synthetic resins, containing an inert filler, that are widely used in dentistry.Tooth Demineralization: A tooth's loss of minerals, such as calcium in hydroxyapatite from the tooth matrix, caused by acidic exposure. An example of the occurrence of demineralization is in the formation of dental caries.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.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.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.Plastics: Polymeric materials (usually organic) of large molecular weight which can be shaped by flow. Plastic usually refers to the final product with fillers, plasticizers, pigments, and stabilizers included (versus the resin, the homogeneous polymeric starting material). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)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)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)Maxillofacial Development: The process of growth and differentiation of the jaws and face.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)Curing Lights, Dental: Light sources used to activate polymerization of light-cured DENTAL CEMENTS and DENTAL RESINS. Degree of cure and bond strength depends on exposure time, wavelength, and intensity of the curing light.Tensile Strength: The maximum stress a material subjected to a stretching load can withstand without tearing. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p2001)Dental Materials: Materials used in the production of dental bases, restorations, impressions, prostheses, etc.Orthodontics: A dental specialty concerned with the prevention and correction of dental and oral anomalies (malocclusion).Orthodontics, Interceptive: Recognition and elimination of potential irregularities and malpositions in the developing dentofacial complex.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)Orthodontic Space Closure: Therapeutic closure of spaces caused by the extraction of teeth, the congenital absence of teeth, or the excessive space between teeth.Mesial Movement of Teeth: Migration of the teeth toward the midline or forward in the DENTAL ARCH. (From Boucher's Clinical Dental Terminology, 4th ed)Diamond: Diamond. A crystalline form of carbon that occurs as hard, colorless or tinted isomeric crystals. It is used as a precious stone, for cutting glass, and as bearings for delicate mechanisms. (From Grant & Hackh's Chemical Dictionary, 5th 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).