update Classification of Malocclusion- updated.pdf
- 2. Classification of malocclusion • Classification is the morphological discription of The dental, skeletal and soft tissue deviation From normal occlusion.
- 3. Purpose of Classification • To be able to distinguish between normal occlusion and malocclusions • To be able to classify malocclusions between and within the jaws, as well as categorise different malpositions of teeth • To understand different malocclusions and their frequencies • To understand what orthodontic treatment need means and what type of malocclusions should or should not be treated • Facilitate communication
- 4. 1. Primary Classification: a) Cephalic anomalies • b) Dysgnathic anomalies • c) Eugnathic anomalies
- 5. a) Cephalic anomalies • Deformities of the osseous components of the head which affect dental occlusion and dentofacial development. It includes the following: • 1) Microcephalus, usually accompanied by a receding chin. • 2) Macrocephalus, usually accompanied by spacing of teeth, mandibular prognathism. • 3) Osteogenic, hyperostosis of the maxilla accompanied by ; -over growth in width and depth of the mandible - retardation of the dentition.
- 6. b) Dysgnathic anomalies • gross developmental abnormalities of the teeth, dental arches, alveolar processes, jaws and other oral structures. It includes the following: 1) Macroglossia, abnormal frenum labia. 2) Facial clefts cleft palate and cleft lip. 3) Total or partial agnathia, or micrognathia. 4) Tumors of the jaws and diseases of the periodontium. 5) Severe changes in the form, structure and relationship of the jaws and teeth which may or may not be associated with systemic diseases.
- 7. c) Eugnathic anomalies: • A term suggested by Lischer used to denote anomalies of the teeth alone which influence occlusion with malformation of alveolar processes but without deformity of the jaws and facial features. It includes the following: • Disturbancein degree of tooth development, impaction, retardation or incompletionof eruption. • Position of tooth or teeth in relation to the line of occlusion, or to any of the three planes of space e.g. Linguoversion, labioversion,
- 8. 2. Classification by body type (BERGER) a. Asthenic or leptosomatic, long and slender: • A tall, thin person with narrow shoulders, • slim arms and hands, the face is high and narrow, • the mandible is underdeveloped • the bridge of the nose overdeveloped in length. b. Pyknic, short and squat: • short in stature with a short neck and compact trunk. • The face is broad and less high than the leptosomatic type. c. Athletic, muscular type: • strong developed muscles, broad shoulders, a fully developed chest. The skeleton is well developed. The mandible is square and fully developed. • The types do not always occur in their pure state • It is types of mixed features that facial disharmony
- 9. 3. Classification according to the etiology (BENNETT): • The malocclusionis classifiedaccording to their etiologic factors: • a. Class I: Abnormal position of one or more teeth due to local etiologicalfactors. • b. Class II: Abnormal developmentof the upper and/or lower arch due to developmentaldefects of the bone. • c. Class III: Malrelationshipof the upper and lower arches to each other, and betweenthe upper and/or lower arch to the face due to developmentaldefects of the bone.
- 10. 4. Classification according to dental arch relationship • Angle’s Classification of Dental Malocclusion • Simon's Classification
- 11. Angle’s Classification of Dental Malocclusion
- 12. the key to occlusion • Angle considered the upper permanent first molars as a fixed point in the skull, • Angle believed that the 1st permanent molars were the key to occlusion: 1 . largest teeth. 2. firmest in their attachment. 3. Have a key location in the arches. 4. Help determine the dental and skeletal vertical proportions 5. Occupy normal position in the arches 6 control the positions of other permanent teeth 7. Have the most consistent timing of 8. Determine the inter-arch relationship of all other teeth upon their eruption and "locking" with the mandibular first molars.
- 13. • Angle based his classification of malocclusion on the normal mesiodistal relations of the permanent canines and of the mesiobuccul cusps of the upper 1st molars in relation to the mandibular canines and 1st molars
- 14. Characteristics of normal dental occlusion • 1. Common occlusal plane for both arches. • 2. Correct axial inclination of the teeth. • 3. Normal relationship of the dental arches to each other and to the face and cranium. • 4. Normal overjet and overbite
- 15. Class I Malocclusion: • The mandibular dental arch and the body of the mandible are in normal mesiodistal relation to the maxillary arch. • The mesiobuccul cusp of the maxillary permanent 1st molars occlude in the buccal groove of the mandibular 1st molars, • the mesiolingual cusp of the maxillary 1st permanent molars occludes with the occlusal fossae of the mandibular permanent 1st molars, • when the jaws are at rest and the teeth are approximated in centric occlusion.
- 16. Angle Class I
- 17. Malocclusion in Class I is localized anterior to the first molar • 1) Local abnormalities: • * Crowding of incisorteeth. • * Labial inclinationof upper incisorteeth. • * Anteriorcross bite. • * Posteriorcross bite. • * Impaction of premolars or canines. • * Deep overbite. • * Open bite (anterioror posterior). • 2) Disproportionin size betweenthe teeth and basal bone (spacing or crowding of teeth).
- 18. Class II Malocclusion • The mandibular dental arch and the body of the mandible are in distalrelation to the maxillary arch. The mesiobucculcusp of the maxillary permanent1st molars occluded in the space betweenthe mesiobuccul cusp of the mandibular permanent 1st molar and the distal aspect of the buccal cusp of the 2nd premolars. The mesiolingualcusps of the maxillary 1st molars occlude mesial to the mesiolingualcusp of the mandibular 1st molars.
- 19. divisions for Class II • There are two : • Division 1 and Division 2. • subdivision: the 1st molars relationship is Class I (normal) in one side, and Class II on the other side
- 20. Angle’s Class II Division 1 dental malocclusion • 1) The upper incisor teeth are proclined. • 2) Excessive overjet and deep overbite. • 3) V-shaped upper arch; Narrow in the canine region and broad between the molars. • 4) Short upper lip with failure in the anterior lip seal. • 5) The mandible may be deficient and under developed chin.
- 21. Angle’s Class II Division 1 dental malocclusion
- 22. • Full unit: mesiodistal width of a premolar or half the width of a permanent 1st molar • Half unit: half the width of a premolar . • Full unit Class II = width of a premolar. • Half unit Class II = half width of a premolar.
- 23. Angle Class II malocclusion Angle Class II malocclusion (full cusp)
- 24. Angle Class II malocclusion (half cusp)
- 25. Angle’s Class II Division 2 • 1) The upper central incisor teeth showed lingual inclination and may be overlapped by the upper lateral incisor teeth. • 2) Deep overbite. • 3) Normal upper lip and lip seal with deep mental groove. • 4) The mandible is of good size.
- 26. Angle’s Class II Division 1 dental malocclusion
- 27. Class II division 2
- 28. Class II subdivision: • The first molar relationship is Class I in one side and Class II in the other side.
- 29. Class III Malocclusion • The mandibular dental arch and the body of the mandible are in bilateral mesial relationship to the maxillary arch. • The mesiobucculcusp of the maxillary permanent1st molar occludes in the interdental space betweenthe distal aspect of the distal cusps of the mandibular permanent 1st molars and the mesial aspect of the mesial cusps of the mandibular 2nd permanent molars. • Typically the teeth are in centric occlusion, and the mandibular condyles are within the glenoid fossae.
- 31. Class III Subdivision The molar relationship: Class III on one side and Class I on the other side, i.e. malocclusion is unilateral.
- 32. Angle Class III malocclusion
- 33. Angle class IV: • The first molar relationship is Class II in one side and Class III in the other side. • It does not have divisions or subdivisions. • It was not originally included in the classification. However, • it was added later.
- 34. Reliability and validity of Angle’s classification: • Angle’s classification was the first comprehensive classification of malocclusion. • It is still the most widely accepted classification and is used routinely up till now
- 35. Reliability: • is the extent to which an experiment or test yields the same results on repeated trials. • Angle’s classification has proven to be highly reliable because the same results are obtained on repeated clinical examination.
- 36. Validity of Angle's Classification • With the introduction of Cephalometric radiographs into clinical orthodontics in the last century by Broadbent, some points were raised against Angle’s classification; such as: • 1. The 1st permanent molar is not a fixed point in the skull. • 2. It is now known that, it is possible to have Class I dental arches on skeletal Class 2. • 3. In Class II, the classification does not differentiate between true mandibular retrusion and maxillary protrusion and also in Class III either true maxillary retrusion or mandibular protrusion. • 4. It is incomplete, as it shows anomalies in anteroposterior direction only and neglecting any anomalies in the vertical or transverse direction. • Angle’s classificationis not valid
- 37. Modification of Angle's Classification • A. Lischer's modification • B. Dewey's modifications
- 38. Modification of Angle's Classification A. Lischer's modification: • Lischer introduced the following to explain Angle's classification: • 1. Neutrocclusion or Class I. • 2. Distocclusion or Class II. • 3. Mesiocclusion or Class III.
- 39. Lischer's terminology • 1. Bucco-occlusion, when the dental arch, quadrant, or group of teeth is buccal to normal. • 2. Linguo-occlusion, when the dental arch, quadrant, or group of teeth is lingual to normal. • 3. Supra-occlusion, abnormally deep overbite of group of teeth, or one dental arch occludes over the opposing arch so that the teeth in the respective jaws overlap abnormally. • 4. Infra-occlusion, dental arches, quadrants, or group of teeth are in open bite relationship.
- 40. B. Dewey's modifications: • Dewey in 1915 modified Angle’s Class I and Class III by segregating malpositions of anterior and posterior segments as:
- 41. MODIFICATIONS OF ANGLES CLASS I • Type 1 Angles Class I with crowded maxillary anterior teeth
- 42. Type 2 Angles Class I with maxillary incisors in labio- version (proclined)
- 43. Type 3 • Angle’s Class I with maxillary incisor teeth in linguoversion to mandibular incisor teeth (anteriors in cross bite) • This type can be mistaken for Class III Angle. •
- 44. Type 4 Molars and/or premolars are in bucco or linguoversion, but incisors and canines are in normal alignment (posteriors in cross bite)
- 45. Type 5 • Molars are in mesio-version due to early loss of teeth mesial to them (early loss of deciduous molars or second premolar)
- 46. Dewey divided Angle’s Class III into 3 types: • Type 1: Teeth are in normal alignment (edge to edge bite). • Type 2: Lower incisors are crowded (normal overjet). • Type 3: Maxillary incisors are crowded (anterior crossbite).
- 47. Dewey's modifications to Angle's Class III malocclusion • Type1: • The dental arches are well formed and the teeth are in normal alignment in the respective arches when viewed individually. • There is an edge-to-edge bite when the attempt is made to approximate the dental arches, • There is an appearance suggesting that the mandibular dental arch has been moved forward bodily.
- 48. Type 2 • The mandibular incisors are crowded • and in lingual relation to the maxillary incisors.
- 49. Type 3 • The maxillary arch is underdeveloped. • The maxillary incisors are crowded • The mandibular arch is well developed • Mandibular teeth are in normal alignment.
- 50. Simon's Classification The Three Planes of Occlusion • It relates the denture to the face and cranium in the three planes of space: 1. the Frankfort horizontal, 2. the orbital, 3. the raphe or median sagittal plane.
- 51. 1. The Frankfort horizontal plane • eye-ear plane: • is determined by drawing a straight line through the margin of the bony orbit directly under the pupil of the eye, to the upper margins of the auditory meat us.
- 52. Deviation from the Frankfort horizontal plane: • a. Attractions: The distance between the occlusal plane and the Frankfort horizontal is comparatively shorter than normal. • b. Abstractions: The distance between the occlusal plane and the Frankfort plane is comparatively longer than normal.
- 53. 2. The orbital plane • is perpendicular to the Frankfort plane, at the margin of the bony orbit directly under the pupil of the eye. • determine sagittal deviations in the ant- post. relation of the dental arches • the axial inclination of the teeth to the face and cranium.
- 54. Deviation from the orbital plane: • Protractions: The teeth, one or both dental arches and/or jaws are too far forward. • (Normally the orbital plane passes through the distal incline of the canine) • Retractions: The teeth, one or both dental arches and/or jaws are too far retruded. The orbital plane passes too far anteriorly to the canines.
- 55. Deviation of the dental arches in relation to the orbital plane according to Simon may occur as follows: 1. Both jaws in normal relation to each other 2. Upper jaw normal, lower jaw mesial 3. Upper jaw normal, lower jaw distal 4. Lower jaw normal, upper jaw mesial 5. Lower jaw normal, upper jaw distal 6. Upper jaw mesial, lower jaw distal 7. Upper jaw distal, lower jaw mesial
- 56. The law of the canine • In normal arch relationship, according to Simon: • the orbital plane passes through the distal axial aspect of the canine. This is known as "the law of the canine".
- 57. 3. The raphe or median sagittal plane • is determined by points approximately 1.5cm apart on the median raphe of the palate. • passes through these two points at right angle to the Frankfort horizontal plane.
- 58. • This plane is used to determine deviation in; - form and width of the dental arches -axial inclination of the teeth in relation to the midline of the palate and the head.
- 59. 1. Deviation from the raphe or median sagittal plane: • a. Contractions: A part or the entire dental arch is contracted toward the raphe median plane. • The abnormality may be alveolar, dental, anterior, posterior, unilateral or bilateral. • b. Distractions: A part or the entire dental arch is wider than usual (cross bite) from the raphe median plane.
- 60. Skeletal Classification of malocclusion • Salzmann is 1950 was the first to classify on olcclusion based on the underlying skeletal structures. • SKELETAL CLASS I • These malocclusions were purely dental with the bones of the face and jaws being in harmony with one another and with the rest of the head. The profile is orthognathic • SKELETAL CLASS II • These included malocclusion with a subnormal distal mandibular development in relation to the maxilla • SKELETAL CLASS III • Here there is an over growth of the mandible with an obtuse mandibular plane angle. The profile is prognathic at the mandible
- 61. Incisor Classification • British standard Classification of incisor relationship • based on incisor relationship proposed in 1983
- 62. Incisor Classification • The incisor classification is considered simpler and more relevant than Angle’s classification. • It was adopted by the British Standards’Institute in 1983, and is based upon the relationship of the lower incisor edges and the cingulum plateau of the maxillary central incisors.