Terminology Of Malocclusion PDF

Terminology of Malocclusion Malocclusion may be defined as: A condition where there is a deviation from the normal relation of the teeth ( or tooth) to other teeth in the same dental arch or the teeth in the opposing dental arch. Malocclusion of the teeth may be associated with one or more...

Terminology of Malocclusion Malocclusion may be defined as: A condition where there is a deviation from the normal relation of the teeth ( or tooth) to other teeth in the same dental arch or the teeth in the opposing dental arch. Malocclusion of the teeth may be associated with one or more of the following conditions: A) Malpositioning of individual teeth in arches and jaws which are themselves normally related to one another. B) Malrelation of dental arches to one another upon bony bases which may themselves be normally related. C) Malrelationship of the bony bases themselves (Skeletal morphology unfavorable for the production of normal occlusion ) A) Mal-positioning of individual teeth. a) Labial inclination (proclination): Outward tilting of the anterior teeth towards the lips. b) Labial and Buccal Displacement (Facial displacement) : Bodily displacement of teeth in a facial direction. c) Lingual inclination: (Retroclination) The crown of the tooth is tilted towards the tongue. Retroclination refers to lingual tilting of the anterior teeth. d) Lingual displacement: A teeth bodily displaced towards the tongue. Labial (facial) Inclination Labial (facial) Displacement Lingual Inclination Lingual Displacement e) Medial inclination: Tooth having its crown abnormality tilted towards the mid-line. j) Medial displacement: A tooth which is bodily displaced towards the mid-line. g) Distal inclination: A tooth having its crown abnormality tilted away from the mid-line. h) Distal displacement: A tooth which is bodily displaced in a direction away from the mid-line. Medial inclination Medial Displacement Distal Inclination Distal Displacement i) Infraocclusion: A tooth has not reached the line of occlusion i.e. have not erupted sufficiently. j) Supraocclusion: A tooth that has passed the line of occlusion i.e. overerupted. Infraocclusion Supraocclusion k) Mediolingual rotation: A tooth which is rotated around its long axis so that its medial aspect is turned towards the tongue. I) Distolingual rotation: A tooth which is rotated around its long axis so that its distal aspect is turned toward the tongue. Mediolingual rotation Distolingurotation m) Transposition: A tooth that has appeared in abnormal numerical order i.e. an upper canine and a lateral incisor changing places. n) Perversion: A tooth completely misplaced or impacted i.e. a lower third molar placed in the ascending ramus or a maxillary canine erupting in the nasal fossa. 0) Imbrication: Describes teeth which are irregularly arranged within the arch due to lack of space for them. Transposition Imbrication LISCHER'S TERMINOLOGY  Lischer used the word "version" to identify the malposition of individual teeth in relation to the line of occlusion.  In normal occlusion,the Angle's line of occlusion: Maxillary: passes through the central fossae and along the cingulae of the maxillary teeth. Mandibular: passes through the buccal cusps and incisal edges of the mandibular teeth. Angle's line of occlusion According to Lischer, malposed individual teeth assumes one or more of the following positions: 1.Transversion: Wrong sequential order, transposition. 2.labioversion or buccoversion (facioversion): Facial to the line of occlusion ( i.e. towered the lips or checks ). 3. Axiversion : Wrong axial angulation ( tip) or inclination ( torque) 4. Torsiversion : Tooth rotated on its long axis. 5. Linguoversion: lingual to the line of occlusion ( i.e. toward the tongue) 6. Supraversion: A tooth that has passed the line of occlusion i. e. overerupted. 8. Infraversion : A tooth has not reached the line of occlusion i.e. have not erupted sufficiently. 7. Mesioverion : mesial to normal position. 9. Distoversion : distal to the normal position. B) Malrelation of the Dental Arches  i) Post-normal occlusion:  This used to describe a condition when the lower dental arch appears to lie too far back in relation to the upper arch when the teeth are closed in centric occlusion.  The term applied to the dental arches relations and does not include the relation of the mandibular basal bone to the maxillary basal bone.  Also it includes conditions when either the lower arch appears distal or the upper arch in a forward position or when both conditions coexist. ii) Pre-normal Occlusion: This describes a condition where the lower dental arch is in advance of the upper dental arch when the teeth are closed in centric occlusion and the condyles are in their normal position within the glenoid fossae. iii) Cross bite : Posterior crossbite: When one or both sides the buccal cusps of one or more upper posterior teeth occlude within the fossa of the lowers, the condition is described as cross- bite.in such cases the upper arch may appear to be rather narrower than normal while the lower arch may appear wider. Anterior crossbite: An anterior cross bite (lingual occlusion) results when one or more of the upper incisor teeth is lingual to the lower incisors. iv ) Openbite : Anterior openbite : In the anterior type, the most distal teeth in the arches occlude; where a space exist between the rest of the teeth in the upper jaw and those in the lower. Posterior openbite : A posterior open bite exists when only the posterior teeth on one or both sides do not occlude. V) Closebite ( deep bite): This describes the condition, when due to failure of the posterior teeth to reach their power eruptive height, the mandible will appear to be in a position of over closure. the anterior teeth may thus appear to have overerupted and to present a deep over - bite. VI) Overbite : It is the amount by which the lower incisors are covered by the upper incisors when the teeth are closed in centric occlusion. It is thus a vertical measurement. VII) Overjet: It is the horizontal distance between the labial aspect of the lower incisors and the lingual aspect of the upper incisors at the incisal edges when the arches are in centric occlusion. It is thus a horizontal measurement. C) skeletal morphology unfavorable for the production of normal occlusion  Certain conditions may affect the shape of either the maxillary basal bone or mandibular basal bone or both.  For example, the mandible may be underdeveloped or a cleft may affect the structure of the maxilla. In either case the development of normal occlusion is improbable.  Certain inherited bone shapes and forms may result in an abnormal pattern of occlusion ,a pre- normal occlusion usually accompanies a large and prominent mandible, especially if it is associated with maxilla which is short anteroposteriorly  supraocclusion Labial /buccal infraocclusion inclinaion or tipping Lingual inclination or tipping Mesiolingual or distolabial rotation Individual Distal inclination tooth or tipping malpositions Distolingual or mesioabial rotation mesial inclination Transposition or tipping Infraversion Supraversion Axiversion Torsiversion Transversion mesiolabial Away Extended Wrong Two adjacent teeth from line past line axial exchanged of of angulati their position occlusion occlusion on (tip) distolabial Example or Rotated Transposition inclinati on its b/w canine &premolar on long axis with absent (torque) lateral incisor  n k Y o u Tha