🌟 DEFINTIONS OF ORTHODONTICS
🔹MALOCCLUSION: Any deviation from normal occlusion.
🔹MOMENT (of a force): The tendency of a force to cause rotation.
🔹NANCE PALATAL ARCH: A maxillary fixed anchorage reinforcing appliance consisting of a wire soldered onto the first molar bands connected to an acrylic button contacting the anterior palatal surface.
🔹NASOLABIAL ANGLE: The angle between a line drawn tangent to the columella of the nose and a line connecting subnasale to the mucocutaneous border of the upper lip.
🔹NATURAL HEAD POSITION: A standardised reproducible head position used for dento-skeletal assessment.
🔹NON-EXTRACTION TREATMENT: Orthodontic treatment without extraction of permanent teeth excluding the third molars.
🔹ORTHOGNATHIC SURGERY: Surgical repositioning of the mandible and/or maxilla for the correction of dentofacial deformity.
🔹OSTEOTOMY: A surgical bone cut.
🔹OVERBITE: The degree of vertical overlap of the mandibular incisors by their maxillary counterparts measured perpendicular to the occlusal plane (normal = 2–4 mm) and with the teeth in occlusion.
🔹OVERJET: The horizontal distance between the labial surfaces of the mandibular incisors and the maxillary incisal edges measured parallel to the occlusal plane to the most prominent point on the maxillary central incisal edges (normal = 2–4 mm).
🔹PARASTHESIA: Reduced or abnormal sensation (e.g. tingling, burning) due to nerve damage that may occur following orthognathic surgery.
🔹POSED SMILE: A voluntary smile, not linked with emotion, that is fairly reproducible (see spontaneous smile).
🔹POSTERIOR ORAL SEAL: A seal produced between the soft palate and dorsal surface of the tongue preventing open communication between the oral cavity and oropharynx.
🔹PRE-SURGICAL ORTHODONTICS: Orthodontic treatment carried out in preparation for orthognathic surgery.
🔹PRIMATE SPACE: A naturally occurring space present mesial to the upper and distal to the lower deciduous canines.
🔹PROGNATHISM: A term used to describe protrusion of the maxilla and/or mandible in relationship to the cranial base.
🔹PUBERTAL (adolescent) GROWTH SPURT: The acceleration in growth associated with puberty.
🔹QUAD HELIX APPLIANCE: A maxillary expansion appliance consisting of a stainless steel wire, incorporating four helices, attached to bands placed onto the maxillary first permanent molars.
🔹RELAPSE: The return of original features of a malocclusion following treatment.
🔹REMOVABLE APPLIANCE: An appliance that can be removed by the patient for the maintenance of oral hygiene.
🔹RETROGNATHIA: A term used to describe retrusion of the maxilla and/or mandible in relationship to the cranial base.
🔹RETENTION: The final phase of orthodontic treatment is aimed at stabilisation of corrected tooth positions.
🔹RICKETTS E-LINE: A line drawn tangent to the chin and nose used to assess lip fullness.
🔹SCISSOR BITE (lingual crossbite): Where the buccal cusps of the lower premolars/molars occlude palatal to their opposing counterparts.
🔹SKELETAL PATTERN: The three-dimensional relationship between the maxilla and the mandible.
🔹SMILE ARC: The relationship between the curvature of the maxillary incisal edges and canine tips to the curvature of the upper border of the lower lip during the posed smile.
🔹SPONTANEOUS SMILE: An involuntary smile, linked with emotion, with the maximal elevation of the upper lip (see posed smile).
🔹SUPERNUMERARY TEETH: Teeth in excess of the normal series.
🔹TRANSSEPTAL FIBRES: Periodontal fibres interconnecting adjacent teeth.
🔹TRAUMATIC OVERBITE: Contact between the lower incisors and palatal mucosa that results in discomfort, inflammation, recession and/or ulceration.
🔹TWO-BY-FOUR APPLIANCE: A fixed appliance attached only to the maxillary first permanent molars (×2) and incisors (×4).
🔹TRANSPALATAL ARCH: A maxillary anchorage reinforcing appliance, consisting of a wire connecting bands placed onto the first permanent molars, that maintains the inter-molar width.