Malocclusion Classification PDF

The classification of malocclusion Dr Muhannad KAZZAZ DDS, MSD, PhD  Classification of Malocclusion Classification of malocclusion is the description of dentofacial deviations according to a common characteristic, or norm. Malocclusions can be broadly divided into three types: 1.Intra-arch m...

The classification of malocclusion Dr Muhannad KAZZAZ DDS, MSD, PhD  Classification of Malocclusion Classification of malocclusion is the description of dentofacial deviations according to a common characteristic, or norm. Malocclusions can be broadly divided into three types: 1.Intra-arch malocclusions: Malocclusion within the same arch, i.e. either maxillary arch or mandibular arch. 2. Inter-arch malocclusions: Malocclusions involving both maxillary and mandibular arches 3. Skeletal malocclusions: Malocclusions involving underlying skeletal structures I- INTRA-ARCH MALOCCLUSIONS Malalignment of individual tooth within the same dental arch are referred as intra-arch malocclusions. Intra-arch malocclusion may be in the form of abnormal inclinations, displacement, rotation, transposition or abnormal position of a tooth. Intra-arch malocclusions can be classified into following types Abnormal Inclinations Th is condition involves an abnormal tilting of a crown,with the root being in normal position. A tooth may be abnormally inclined in any of the four directions. Buccal Inclination This refers to labial (in case of anteriors) or buccal (in case of posteriors) tilting of the tooth crown. Lingual Inclination This refers to palatal (maxillary teeth) or lingual (mandibular teeth) tilting of the tooth crown. Mesial Inclination Refers to tilting of the tooth crown towards the midline Distal Inclination This refers to tilting of the tooth crown away from midline Displacement This involves bodily movement of the crown, as well as the root of a tooth in the same direction to occupy an abnormal location. A tooth can be displaced in any of the four directions. Buccal Displacement This term refers to bodily movement of the tooth in labial/ buccal direction Lingual Displacement This term refers to bodily movement of the tooth in a lingual direction Mesial Displacement This term refers to bodily movement of tooth in a mesial direction towards the midline Distal Displacement Rotation This term refers to the movement of a tooth around its long axis. A tooth may be rotated in two directions: 1. Mesiolingual (distolabial) or 2. Distolingual (mesiolabial) direction Transposition This term refers to a condition in which two teeth have exchanged places Infra/Supraversion A tooth is said to be in infra/supraversion, when it is not at the level of occlusion as compared to other teeth in the arch depending on its rate of eruption II - INTERARCH MALOCCLUSIONS - Sagittal plane - Transversal plane - Vertical plane  SAGITTAL PLANE MALOCCLUSIONS Molar relationship - neutroclusion (class I) - distoclusion (class II) - mesioclusion (class III) Canine relationship  incisor relationship Overjet Overjet is defined as horizontal overlap of the incisors. Normally, the incisors are in contact, with the upper incisors ahead of the lower by only the thickness of their incisal. edges i.e., 2-3 mm overjet is the normal relationship Excessive - Edge to edge - Anterior crossbite - VARTICAL PLANE MALOCCLUSIONS Overbite is defined as vertical overlap of the incisors Deep Bite - Open Bite -  TRANSVERSE PLANE MALOCCLUSIONS - Upper & Lower Dental Midlines  Buccal crossbite  Lingual crossbite III- SKELETAL MALOCCLUSION ANGLE’S CLASSIFICATION In 1899, Edward Angle classified malocclusion based on the mesial-distal relation between first permanent molars He considered the maxillary first molar as a fixed point (key of occlusion) Angle's classification class I :the mesiodistal cusp of the upper first molar occluding in the buccal groove of the lower first molar CLASS II- MALOCCLUSION Class II - Division 1 : protrusion of the upper incisor Class II - Division 2 : retrusion of the upper incisor - Class II - Division 1 - Class II - Division 2 CLASS III –MALOCCLUSION Drawback of Angle's classification  1. Angle presumed the first permanent molars as fixed points within the jaws, which definitely is not so  2. Angle depended exclusively on the first molars. Hence, the classification is not possible if the first molars are missing or if applied in the deciduous dentition  3. Malocclusions are considered only in the anteroposterior plane. Maloccluslon in the transverse and vertical planes arc not considered  4. Individual tooth malocclusions have not been considered  5. There is no differentiation between skeletal and  DEWEY'S MODIFICATION OF ANGLE'S CLASSIFICATION OF MALOCCLUSION MODIFICATIONS OF ANGLES CLASS I  Type 1: Angles Class I with crowded maxillary anterior teeth  Type 2: Angles Class I with maxillary incisors in labio- version (proclined)  Type 3: Angle's Class I with maxillary incisor teeth in linguoversion to mandibular incisor teeth (anteriors in cross bite).  Type 4: Molars and/ or premolars are in bucco or linguoversion, but incisors and canines are in normal alignment (posteriors in cross bite).  Type 5: Molars are in mesio-version due to early loss of British Standards Institute incisor classification/ Incisor classification  Canine relationship The canine relationship also provides a useful anteroposterior occlusal classification: Class I – the maxillary permanent canine occludes in the embrasure between the lower canine and first premolar Class II – the maxillary canine occludes anterior to the embrasure between the lower canine and first premolar. The severity of the malrelationship can be described as a fraction of a tooth unit. Class III – the maxillary canine occludes posterior to the embrasure between the lower canine and first premolar. Andrews’ six keys  Andrews analysed 120 ‘normal’ occlusions to evaluate those features which were key to a good occlusion (it has been pointed out that these occlusions can more correctly be described as ‘ideal’).  He found six features, These six keys are not a method of classifying occlusion as such, but serve as a goal. 31 dr. muhannad kazzaz  ACKERMAN-PROFITT SYSTEM OF CLASSIFICATION  Ackerman and Profitt proposed a very comprehensive system of classification which divided malocclusions in all the three planes of space and tended to give an indication towards the severity of the malocclusion present.