CLASSIFICATION OF MALOCCLUSION in orthodontics

classification of malocclusion

1. CLASSIFICATIONOF MALOCCLUSION Dr Farzana Beegum I st year MDS

2. CONTENTS INTRODUCTION DEFINITION HISTORICAL REVIEW ANDREWS 6 KEYS OF NORMAL OCCLUSION NEED FOR CLASSIFICATION TYPES OF MALOCCLUSION INTRA ARCH INTER ARCH SKELETAL CLASSIFICATION OF MALOCCLUSION ANGLES CLASSIFICATION AND ITS MODIFICATIONS

3. McNAMARA’S CLASSIFICATION MOYER’S CLASSIFICATION CANINE CLASSIFICATION BALLARD’S INCISOR CLASSIFICATION KAT’S PREMOLAR CLASSIFICTION ACKERMAN – PROFFIT SYSTEM OF CLASSIFICATION SIMON’S CLASSIFICATION BENNETT’S CLASSIFICATION CONCLUSION REFERENCES

4. INTRODUCTION Understanding the different types of malocclusions is essential for accurate diagnosis and effective treatment planning in orthodontics. Today, we will delve into the various classification systems, including Angle’s classification and various other classification systems, and discuss how these frameworks aid in developing personalized treatment strategies. A classification system pioneers the knowledge and attempts to arrange into groups or classes having one or more common characteristics.

5. DEFINITION What Is Occlusion? The relationship of the maxillary and mandibular teeth when the jaws are closed in centric relation.

6. What Is Malocclusion? Malocclusion may be defined as “A condition where there is departure from the normal relation of the teeth to other teeth in the same dental arch and/or to teeth in the opposing arch.”[ Edward H Angle]

7. It is a condition that reflects an expression of normal biologic variability in the way the maxilla and mandible teeth occlude (BISHARA) An occlusion in which there is a mal relationship between the arches in any of the planes of the spaces or in which there are anomalies in tooth position beyond the limit of normal. (WALTHER & HUSTON)

8. IDEAL OCCLUSION: It is a pre- conceived theoretical concept of occlusal structures and functional relationships that include idealized principles and characteristics that an occlusion should have. NORMAL OCCLUSION: It is some deviation from that of ideal but is aesthetically acceptable and functionally stable for the individuals. The upper and lower teeth fit nicely and evenly together with the least amount of destructive interferences.

9. What is a classification system ?? “A classification system is a grouping of clinical cases of similar appearance for ease in handling and discussion; it is not a system of diagnosis , method for determining prognosis ,or a way of defining treatment” Robert E.Moyers

10. HISTORICL REVIEW ( 1829) Samuel S Fitch - described in his book‘ A System of Dental Surgery’ first classified into 4 states of irregularity. (1836) Christopher kneisel - ‘The oblique position of teeth’ classified –general obliqueness & partial obliqueness. (1839) Jean Nicolas Marjolin - differentiated obliqueness of teeth and anomalies of dental arch.

11. (1842) George Carabelli - coined the term edge-to-edge bite and overbite. Classification was based on the positions of incisors and canines which has termed as: Mordex Normalis : Normal occulsion Mordex rectus : Edge to edge Mordex apertus : Open occlusion Mordex prorsus : protruding occlusion Mordex retrous : Retruding occlusion Mordex tortuosus : Zig –zag occlusion

12. (1880) Norman Kingsely – classified into 2 broad categories based on etiology Developmental malocclusion Accidental malocclusion Edward H Angle ( 1899, 1900, 1906,1907 ) – detailed description of malocclusion into 3classes (1905-1921) Calvin case -anatomical groups- grouped into 5 classes (1912 ) Lischer – terms distocclusion and mesiocclusion

13. (1915) Martin Dewey –modified Angles classes (1920) Paul Simon-based on the gnathostatics and canine law (1964) Ballard and Wayman - British classification based on incisor overjet (1969) Ackerman and proffit - based on venn diagram (1992) Katz- based on premolar as a reference

14. The World Health Organization (1987), had included malocclusion under the heading of Handicapping Dento Facial Anomaly , defined as an anomaly which causes disfigurement or which impedes function, and requiring treatment, if the disfigurement or functional defect was likely to be an obstacle to the patient’s physical or emotional well-being.

15. Andrews 6 Keys of Normal Occlusion (1972) Andrews in 1970s put forward the six keys to normal occlusion after studying models of 120 patients with ideal occlusion. The six keys to normal occlusion are considered under following headings. Andrews LF. The six keys to normal occlusion. Am J Orthod . 1972 Sep 1;62(3):296-309.

16. 1. Molar relationship . The distal surface of the distobuccal cusp of the upper first permanent molar made contact and occluded with the mesial surface of the mesio buccal cusp of the lower second molar. The mesio buccal cusp of the upper first permanent molar fell within the groove between the mesial and middle cusps of the lower first permanent molar. Andrews LF. The six keys to normal occlusion. Am J Orthod . 1972 Sep 1;62(3):296-309.

17. 2 . Crown angulation The term crown angulation refers to angulation (or tip) of the long axis of the crown, not to angulation of the long axis of the entire tooth. The gingival portion of the long axis of each crown was distal to the incisal portion, varying with the individual tooth type. The long axis of the crown for all teeth, except molars, is judged to be the mid developmental ridge, which is the most prominent and centermost vertical portion of the labial or buccal surface of the crown. Andrews LF. The six keys to normal occlusion. Am J Orthod . 1972 Sep 1;62(3):296-309.

18. 3 . Crown inclination (labiolingual or buccolingual inclination). Crown Inclination refers to the labiolingual or buccolingual inclination of the long axis of the crown, not to the inclination of the long axis of the entire tooth. Andrews LF. The six keys to normal occlusion. Am J Orthod . 1972 Sep 1;62(3):296-309.

19. 4. Rotations . There were no rotations. 5. Tight contacts . There were no spaces; contact points were tight. 6. Occlusal plane . The plane of occlusion varied from generally flat to a slight curve of Spee Andrews LF. The six keys to normal occlusion. Am J Orthod . 1972 Sep 1;62(3):296-309.

20. NEED FOR CLASSIFICATION Acquire a better understanding of deviation from normal occlusion. To identify the problem (Diagnosis) For better treatment planning Alter ourselves to possible strategies and appliances, that may be needed in treatment. Recalling pass difficulties with similar cases. Comparison of the various malocclusion is made easy by classification. Ease of reference For communication Used For Epidemiological Studies.

21. INTRA-ARCH MALOCCLUSIONS It includes: Abnormal inclination. Abnormal displacement. Spacing and crowding within same arch.

22. ABNORMAL INCLINATIONS: 1) Mesial inclination : This is a condition where the crown of tooth is tilted or inclined mesially . 2) Distal inclination : Refers to a condition where the crown is tilted or inclined distally.

23. 3) Lingual inclination (Retroclination): This is an abnormal lingual or palatal tilting of tooth. 4) Buccal inclination (Proclination): This refers to labial or buccal inclination of tooth.

24. ABNORMAL DISPLACEMENT: 1) Mesial displacement : This refers to a tooth that is bodily moved in a mesial direction towards the midline. 2) Distal displacement : This refers to a tooth that is bodily moved in a distal direction away from the midline.

25. 3) Lingual displacement : This is a condition where the entire tooth is displaced in lingual direction. 4) Buccal displacement : This is a condition where the tooth is displaced bodily in labial or buccal direction.

26. 5) Extrusion(supra-version): This is a condition in which a tooth that has over erupted as compared to other teeth in the arch. 6) Intrusion(infra-version): Refers to a tooth that has not erupted enough as compared to other teeth in the arch.

27. 7 ) Disto -lingual or mesio -buccal rotation : This describes a tooth that has rotated around its long axis so that the distal aspect is more lingually placed. 8 ) Mesio -lingual or disto -buccal rot ation: This is a condition where the tooth has rotated around its long axis so that the mesial aspect is more lingually placed.

28. 9) Transposition : This term describes a condition where two teeth have exchanged places.

29. INTER-ARCH MALOCCLUSIONS: These inter-arch malocclusions can occur in the: Sagittal plane Vertical plane Transverse plane of space.

30. SAGITTAL PLANE MALOCCLUSIONS: This includes condition where the upper and lower arches are abnormally related to each other in a sagittal plane. 1) Pre-normal occlusion : This is a condition where the lower arch is more forwardly placed when the patient bites in centric occlusion. 2) Post-normal occlusion : This is a condition where the lower arch is more distally placed when the patients bite in centric occlusion.

31. VERTICAL PLANE MALOCCLUSIONS: 1) Deep bite or increased overbite : It is a condition where there is excessive vertical overlap between the upper and lower anterior. 2) Open bite : This is a condition where there is no vertical overlap between upper and lower teeth. Thus a space may appear between the upper and lower arch when the patient bites in centric occlusion it can either be in anterior or posterior region.

32. TRANSVERSE PLANE MALOCCLUSIONS: It includes various types of crossbites and scissor bites. Crossbite : the term crossbite refers to abnormal transverse relationship between upper and lower arches. A crossbite may affect a single tooth or a group of a teeth or an entire arch. It may affect posterior or anterior tooth alone, or both in combination. Posterior crossbite can be unilateral or bilateral. Scissor bite : it is a condition in which the mandibular arch is contained within the maxillary arch.

33. Skeletal malocclusions They are the mal relations of apical bases of upper and lower arch. It is due to : Abnormal size Abnormal shape Abnormal relation to the skull Abnormal relation to each other

34. Skeletal dental base relationship can be divided in to three In a normal or skeletal class I relationship, the upper jaw should be approximately 2 to 4mm in front of the lower; In a skeletal class II relationship the lower jaw is greater than 4mm behind the upper; and In a skeletal class III relationship the lower jaw is less than 2mm behind the upper. Cobourne MT, DiBiase AT. Handbook of orthodontics. Elsevier Health Sciences; 2015 Oct 2.

35. ANGLES SYSTEM OF CLASSIFICATION EDWARD ANGLE the “Father of Modern Orthodontics” introduced a system of classifying malocclusion in the year 1899. Angles classification is still in use after almost 100 years of its introduction due to its simplicity in application. Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

36. Basis for Angle’s Classification Angles classification was based on the mesiodistal relation of the teeth, dental arches and the jaws. According to Angle, the maxillary 1st permanent molar is the key to occlusion. He considered these teeth as fixed anatomical points within the jaws. Based on the relation of the lower 1st permanent molar to the upper 1st permanent molar he classified mal occlusions into three main classes designated by the Roman numerals I, II & III.

37. Angle’s Class I Characterized by normal inter-arch molar relation. The mesio -buccal cusp of the maxillary first permanent molar occludes in the buccal groove of mandibular first permanent molar. Patient may exhibit dental irregularities such as crowding, spacing, rotations, missing tooth etc. These patient exhibit normal skeletal relation and also shows normal muscle function. Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

38. Bimaxillary Protrusion Another malocclusion that is most often categorized under class I is bimaxillary protrusion where the patient exhibits a normal class I molar relationship but both the upper and lower arches are forwardly placed.

39. Angle’s Class II These group is characterized by class II molar relation. The disto -buccal cusp of the upper first permanent molar occludes in the buccal groove of the lower first permanent molar. Angle has sub classified class II malocclusion into 2 division 1. Class II division 1 2. Class II division 2 Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

40. Class II Division 1 These is characterized by proclined upper incisor with a resultant increase in overjet. Characteristic feature is the presence of abnormal muscle activity. The upper lip is usually hypotonic, short and fails to form a lip seal. The lower lip cushions the palatal aspect of the upper teeth, a typical feature is ‘Lip Trap’. Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

41. Class II Division 2 It also exhibit the class II molar relationship The classic feature is presence of lingually inclined upper central incisors and labially tipped upper lateral incisors. The patient exhibits a deep anterior overbite. The lingually inclined upper incisors give arch a squarish shape. The mandibular labial gingival tissue is often traumatized by the excessively tipped upper central incisors. Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

42. Class II Subdivision In these class II molar relation exists on one side and a class I relation on the other, it is refered to as class II subdivision

43. Angle’s Class III These group is characterized by class III molar relation. Mesio -buccal cusp of the maxillary first permanent molar occlude in the interdental space between the mandibular first and second molar. It is classified into two group: 1. True class III 2. Pseudo class III Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

44. True Class III This can occur due to following causes: 1. Excessively large mandible 2. Forwardly placed mandible 3. Smaller than normal maxilla 4. Retropositioned maxilla 5. Combination of the above causes The patient can present with a normal overjet, an edge to edge incisor relation or an anterior crossbite. The space available for tongue is usually more. Thus the tongue occupies a lower position, resulting in a narrow upper arch. Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

45. Pseudo Class III This type of malocclusion is produced by a forward movement of the mandible during jaw closure, thus it is also called ‘postural’ or ‘habitual’ class III malocclusion. Following are some causes of pseuso class III malocclusion. 1. Presence of occlusal prematurities may deflect the mandible forward. 2. In case of premature loss of deciduous posteriors, the child tends to move the mandible forward to established contact in the anterior region. 3. A child with enlarged adenoids tends to prevent the tongue from contacting the adenoids. Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264.

46. Class III Subdivision This is a condition characterized by a class III molar relation on one side and a class I relation on the other side

47. Advantages of Angle’s classification First comprehensive classification- most widely accepted Simple Easy to use Most popular Easy to Communicate

48. Drawbacks Of Angle’s Classification 1. Angle considered malocclusion only in the anteroposterior plane. He didn’t consider malocclusion in the transverse and vertical planes. 2. Angle considered the first permanent molars as fixed points in the skull. But this is not found to be so. 3. The classification can’t be applied if the first permanent molars are extracted or missing. 4. The classification can’t be applied to the deciduous dentition. 5. The classification does not differentiate between skeletal and dental malocclusion. 6. The classification does not highlight the etiology of the malocclusion. 7. Individual tooth malposition have not been considered by Angle.

49. DEWEY’S MODIFICATION OF ANGLES MALOCCLUSION (1915) Divided Angles class I into five types and angles class III into three types Class I modification of Dewey Class III modification of Dewey Dewey M. Classification of malocclusion. Int J Orthodontia 1915;1:133-47

50. Type 1 : Class I malocclusion with bunched or crowded anterior teeth Type 2 : class I with protrusive maxillary incisors Type 3 : Class I with anterior crossbite Dewey M. Classification of malocclusion. Int J Orthodontia 1915;1:133-47

51. Type 4 : Class I malocclusion with posterior crossbite Type 5 : the permanent molar has drifted mesially due to early extraction of second deciduous molar or second premolar. Dewey M. Classification of malocclusion. Int J Orthodontia 1915;1:133-47

52. Class III modification of Dewey Type 1 :Normal incisor overlapping present Type 2 : Edge to edge incisor relationship Type 3 : Incisors are in crossbite Dewey M. Classification of malocclusion. Int J Orthodontia 1915;1:133-47

53. Lischer’s modification Lischer in 1912 substituted the term class I class II and class III given by Angle with the terms Neutrocclusion , Distocclusion and Mesioclusion Neutrocclusion : Angles class I malocclusion Distocclusion : Angles class II malocclsion Mesiocclusion : Angles class III malocclusion Lischer BE. Principles and methods of orthodontics: An introductory study of the art for students and practitioners of dentistry. Lea & Febiger ; 1912.

54. Labioversion : Labial placement of a tooth or a group of teeth Linguoversion : lingual placement of a tooth or a group of a tooth or a group of teeth Lischer BE. Principles and methods of orthodontics: An introductory study of the art for students and practitioners of dentistry. Lea & Febiger ; 1912.

55. Supraversion : when a tooth or group of teeth have erupted beyond normal level Infraversion : when a tooth or group of teeth have not erupted to normal level Lischer BE. Principles and methods of orthodontics: An introductory study of the art for students and practitioners of dentistry. Lea & Febiger ; 1912.

56. Mesioversion : mesial to the normal position Distoversion : distal to the normal position Transversion : transposition of two teeth Lischer BE. Principles and methods of orthodontics: An introductory study of the art for students and practitioners of dentistry. Lea & Febiger ; 1912.

57. Axiversion : Abnormal axial inclination of a tooth Torsiversion : Rotation of a tooth around its long axis Lischer BE. Principles and methods of orthodontics: An introductory study of the art for students and practitioners of dentistry. Lea & Febiger ; 1912.

58. McNAMARA’S CLASSIFICATION Two major types of skeletal combinations in class II children have been defined by McNamara. In the first group, mandibular retrusion is the single most characteristic feature contributing to class II pattern. The skeletal maxillary protrusion is not the major finding, but often normal finding. In the second group, a combination of maxillary and mandibular skeletal retrusion is often found in association with altered mode of respiration ie ; mouth breathing. McNAMARA Jr JA. Components of Class II malocclusion in children 8–10 years of age. The Angle Orthodontist. 1981 Jul;51(3):177-202.

59. MOYERS CLASSIFICATION Moyers stated that while within a population of class II malocclusion cases could be clustered quite unambiguously the distinction between class I and class II is not that obviously distinct. Based on advanced analytical computer based statistical methods of cephalometric records of 697 North American Children, they segregated six horizontal class II types and five vertical class II types of pattern. 1. Horizontal type class II – A B C D E F 2. vertical type class II - 1 2 3 4 5 Moyers RE, Riolo ML, Guire KE, Wainright RL, Bookstein FL. Differential diagnosis of Class II malocclusions: Part 1. Facial types associated with Class II malocclusions. American journal of orthodontics. 1980 Nov 1;78(5):477-94.

60. HORIZONTAL TYPE CLASS II They are divided in to 6 different subtypes: 1. Class II type A Normal skeletal profile Normal position of maxilla and mandible. Normal occlusal plane. Normal mandibular dentition Maxillary dentition placed forward in class II molar increased overjet and bite Moyers RE, Riolo ML, Guire KE, Wainright RL, Bookstein FL. Differential diagnosis of Class II malocclusions: Part 1. Facial types associated with Class II malocclusions. American journal of orthodontics. 1980 Nov 1;78(5):477-94.

61. 2. Class II type B Class II skeletal profile Midface prominence Normal mandible Flat anterior cranial base 3. Class II Type C Smaller facial dimensions than other class II types. Maxilla and mandible retrognathic Lower incisors tipped labially Upper incisors tipped labially/upright Squarish gonial angle Flat anterior cranial base Moyers RE, Riolo ML, Guire KE, Wainright RL, Bookstein FL. Differential diagnosis of Class II malocclusions: Part 1. Facial types associated with Class II malocclusions. American journal of orthodontics. 1980 Nov 1;78(5):477-94.

62. 4. Class II type D normal midface Small mandible Mandibular incisors upright /lingually inclined Maxillary incisors tipped labially 5. Class II type E Prominent midface Normal / Prominent mandible Bimaxillary protrusion Maxillary/mandibular incisors proclined 6. Class II type F No specific features to be well defined, but has a loose collection of cases with some class II characteristics

63. VERTICAL TYPE CLASS II Five types of vertical types are segregated which are not as clearly distinguished as the Horizontal class II. They are: 1. Vertical type 1 Suggestive of long face syndrome or steep mandibular plane angle type of class II 2. Vertical Type 2 Squarish type of face Anterior cranial fossa is more horizontal than normal. Moyers RE, Riolo ML, Guire KE, Wainright RL, Bookstein FL. Differential diagnosis of Class II malocclusions: Part 1. Facial types associated with Class II malocclusions. American journal of orthodontics. 1980 Nov 1;78(5):477-94.

64. 3. Vertical Type 3 Distinct class II associated with skeletal anterior open bite and increased anterior facial height. The palatal plane is tipped anteriorly. 4. Vertical Type 4 Rare and severe anomalous vertical class II type. The mandibular plane, functional occlusal plane, and palatal plane are markedly tipped downward. 5. Vertical Type 5 Seen in bimaxillary protrusion horizontal class II where face is squarish Mandibular plane and functional occlusal plane are normal associated with a small gonial angle resulting in skeletal deep bite.

65. BALLARDS CLASSIFICATION/ BRITISH STANDARDS INSTITUTE INCISOR CLASSIFICATION. A more clinically relevant method of classifying malocclusion is based upon the relationship of the maxillary and mandibular incisors. This represents a truer reflection of the underlying skeletal base relationship and also highlights what is often of most concern to the patient. It is essentially the Angle classification, as applied to the incisor teeth, and is defined upon the relationship of the mandibular incisor tip to the cingulum plateau of the maxillary central incisors being included in the British Standards Institute’s Glossary of Dental Terms Cobourne MT, DiBiase AT. Handbook of orthodontics. Elsevier Health Sciences; 2015 Oct 2.

66. Class I —the lower incisor tips occlude or lie below the cingulum plateau of the upper incisors Class II —the lower incisor tips occlude or lie posterior to the cingulum plateau of the upper incisors. This classification is further subdivided into: Class II division 1 —the overjet is increased with upright or proclined upper incisors; Class II division 2 —the upper incisors are retroclined , with a normal or occasionally increased overjet. Cobourne MT, DiBiase AT. Handbook of orthodontics. Elsevier Health Sciences; 2015 Oct 2.

67. Class III —the lower incisor tips occlude or lie anterior to the cingulum plateau of the upper incisors. Confusion can arise when the upper incisors are upright or retroclined , but with an increased overjet. This has led to the introduction of a class II intermediate classification (Williams and Stephens, 1992): Class II intermediate —the lower incisor edges lie posterior to the cingulum plateau of the upper central incisors. The upper incisors are upright or slightly retroclined and the overjet lies between 5 and 7-mm. In reality, an increased overjet with retroclined upper incisors is within the descriptive range of class II division 2. Cobourne MT, DiBiase AT. Handbook of orthodontics. Elsevier Health Sciences; 2015 Oct 2.

68. CANINE CLASSIFICATION CLASS I - Mesial slope of upper canine Coincides with the distal slope of lower canine CLASS II - Distal slope of upper canine coincides with the mesial slope of the lower canine. CLASS III - Mesial slope of upper canine coincides with that of distal slope of lower 1st premolar

69. KATZ PREMOLAR CLASSIFICATION (1992) PREMOLAR CLASS I - most anterior upper premolar fits exactly into the embrasure created by the distal contact of the most anterior lower premolar represent prefect interdigitations. Katz MI. Angle classification revisited 2: a modified Angle classification. American Journal of Orthodontics and Dentofacial Orthopedics. 1992 Sep 1;102(3):277-84.

70. Premolar class II- the most anterior upper premolar is occluding mesial to the embrasure created by the distal contact of the most anterior lower premolar Katz MI. Angle classification revisited 2: a modified Angle classification. American Journal of Orthodontics and Dentofacial Orthopedics. 1992 Sep 1;102(3):277-84.

71. PREMOLAR CLASS II I- the most anterior upper premolar is occluding distal of the embrasure created by the distal contact of the most anterior lower premolar. Katz MI. Angle classification revisited 2: a modified Angle classification. American Journal of Orthodontics and Dentofacial Orthopedics. 1992 Sep 1;102(3):277-84.

72. Advantages This system provides a quantitative treatment objective that is needed to attain excellent buccal occlusion It provides some flexibility in terms of finishing a case in functional class II or class III buccal occlusion ,while keeping buccal interdigitation as the prime goal In deciduous and mixed dentition cases, emphasis is shifted from the permanent first molars to the region of current importance i.e. deciduous molar region

73. Disadvantages Premolars, are commonly missing, malformed or supernumerary, hence measurement is not always possible Severely rotated and ectopically erupted premolars problems No consideration for the facial balance and aesthetics

74. ACKERMAN-PROFIT SYSTEM ( 1969) Ackerman & Proffit in 1960 Diagrammatic classification of malocclusion Takes into consideration Angle’s classification and five characteristics in a Venn diagram Ackerman JL, Proffit WR. The characteristics of malocclusion: a modern approach to classification and diagnosis. American Journal of Orthodontics and Dentofacial Orthopedics. 1969 Nov 1;56(5):443-54.

75. This classification system follows a definite sequence of evaluating the various dentofacial characteristics in steps. Step 1 (alignment ) Involves assessment of the alignment and symmetry of the dental arch when seen in the occlusal view ideal / crowded / spaced Step 2 (profile and facial divergence) convex / straight / concave anterior or posterior divergence. Ackerman JL, Proffit WR. The characteristics of malocclusion: a modern approach to classification and diagnosis. American Journal of Orthodontics and Dentofacial Orthopedics. 1969 Nov 1;56(5):443-54.

76. Step 3 (type) The transverse skeletal and dental relationship is evaluated. cross bites – unilateral or bilateral – skeletal and dental Step 4 (class) Assessment of the sagittal relationship Classified as Angle’s class I /class II/ class III Differentiation is made between skeletal and dental malocclusions Ackerman JL, Proffit WR. The characteristics of malocclusion: a modern approach to classification and diagnosis. American Journal of Orthodontics and Dentofacial Orthopedics. 1969 Nov 1;56(5):443-54.

77. Step 5 (bite depth) Malocclusions in the vertical plane are noted Described as – anterior or posterior open bite, – deep bite – posterior collapsed bite Skeletal dental Ackerman JL, Proffit WR. The characteristics of malocclusion: a modern approach to classification and diagnosis. American Journal of Orthodontics and Dentofacial Orthopedics. 1969 Nov 1;56(5):443-54.

78. PITCH, ROLL AND YAW

79. PITCH The vertical relationship of the teeth to the lips & cheeks can be conventionally described as up down deviations around the antero-posterior axes. Evaluated clinically & from cephalometric Radiographs ROLL Roll describes the vertical position of the teeth when this is different on the right & left sides. Viewed as up-down deviations around the transverse axes. It’s seen with lips relaxed and more clearly on smile, in both frontal and oblique views .

80. YAW Rotation of the jaw or dentition to one side or the other, around a vertical axes, produces a skeletal or dental midline discrepancy. Viewed as left-right deviations around the vertical axis.

81. BENNET’S CLASSIFICATION Based on ETIOLOGY CLASS I - Abnormal position of one or more teeth due to local causes CLASS II- Abnormal formation of a part or a whole of either arch due to developmental defects of bone CLASS III- Abnormal relationship between upper and lower arches, and between either arch and facial contour and correlated abnormal formation of either arch

82. SIMONS CLASSIFICATION (1920) It is a craniometric classification. Made use of anthropometric planes i.e - FH plane - Orbital - midsagittal Classification was based on abnormal deviations of dental arches form their normal position in relation to these three planes. Simon PW. On gnathostatic diagnosis in orthodontics. International Journal of Orthodontia, Oral Surgery and Radiography. 1924 Dec 1;10(12):755-85.

83. FRANKFORT HORIZONTAL PLANE : - It connects the margin of the external auditory meatus to the infra-orbital margin. This plane is used to classify malocclusions in vertical plane. When the dental arch or part of it is closer than normal to Frankfort plane, it is called attraction. When the dental arch or part of it is farther away from the Frankfort plane, it is called abstraction . Simon PW. On gnathostatic diagnosis in orthodontics. International Journal of Orthodontia, Oral Surgery and Radiography. 1924 Dec 1;10(12):755-85.

84. Orbital plane :-This plane is perpendicular to the Frankfort plane, dropped down from the bony orbital margins directly under the pupil of the eye. According to Simon, this plane should pass through the distal third of upper canine called as Simon’s law of canine. This plane is used to describe malocclusion in sagittal or antero-posterior direction. When the dental arch or part of it is away from orbital plane, it is called as protraction. When the dental arch is closer or placed more posteriorly to this plane, it is called as retraction.

85. Mid sagittal plane :- It is used to describe malocclusion in transverse direction. When a part or whole of arch is away from the this plane, it is called as distraction. When the dental arch is near to this plane, it is called as contraction. Simon PW. On gnathostatic diagnosis in orthodontics. International Journal of Orthodontia, Oral Surgery and Radiography. 1924 Dec 1;10(12):755-85.

86. Drawbacks of Simon’s classification Maxillary canines does not coincide with orbital plane Clinical application not practical Cumbersome and confusing at times

87. CONCLUSION In conclusion, the classification of malocclusion is fundamental for diagnosing and planning effective orthodontic treatments. By understanding the various types of malocclusions and their classifications, we can tailor interventions to meet each patient’s unique needs. This approach not only enhances treatment outcomes but also contributes to the overall goal of improving dental health and aesthetics. As we continue to advance in orthodontic techniques and technologies, a solid grasp of these classifications will remain crucial in delivering the best possible care.

88. REFERENCES 1. Andrews LF. The six keys to normal occlusion. Am J Orthod . 1972 Sep 1;62(3):296-309. 2. Cobourne MT, DiBiase AT. Handbook of orthodontics. Elsevier Health Sciences; 2015 Oct 2. 3. Angle, E.H. (1899) Classification of malocclusion. Dental Cosmos, 41, 248-264. 4. Dewey M. Classification of malocclusion. Int J Orthodontia 1915;1:133-47 5. Lischer BE. Principles and methods of orthodontics: An introductory study of the art for students and practitioners of dentistry. Lea & Febiger ; 1912. 6. McNAMARA Jr JA. Components of Class II malocclusion in children 8–10 years of age. The Angle Orthodontist. 1981 Jul;51(3):177-202. 7. Moyers RE, Riolo ML, Guire KE, Wainright RL, Bookstein FL. Differential diagnosis of Class II malocclusions: Part 1. Facial types associated with Class II malocclusions. American journal of orthodontics. 1980 Nov 1;78(5):477-94.

89. 8. Katz MI. Angle classification revisited 2: a modified Angle classification. American Journal of Orthodontics and Dentofacial Orthopedics. 1992 Sep 1;102(3):277-84. 9. Ackerman JL, Proffit WR. The characteristics of malocclusion: a modern approach to classification and diagnosis. American Journal of Orthodontics and Dentofacial Orthopedics. 1969 Nov 1;56(5):443-54. 10. Simon PW. On gnathostatic diagnosis in orthodontics. International Journal of Orthodontia, Oral Surgery and Radiography. 1924 Dec 1;10(12):755-85.

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