Classification of malocclsion /certified fixed orthodontic courses by Indian dental academy

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Classification of malocclsion /certified fixed orthodontic courses by Indian dental academy

  1. 1. CLASSIFICATION OFCLASSIFICATION OF MALOCCLSIONMALOCCLSION INDIAN DENTAL ACADEMYINDIAN DENTAL ACADEMY Leader in continuing dental educationLeader in continuing dental education www.indiandentalacademy.comwww.indiandentalacademy.com www.indiandentalacademy.comwww.indiandentalacademy.com
  2. 2.  CONTENTSCONTENTS  IntroductionIntroduction  HistoryHistory  ClassificationClassification  Systems of ClassificationSystems of Classification  Angle’sAngle’s  Lischer’sLischer’s  Bennet’sBennet’s  Simon’sSimon’s  IncisorIncisor  CanineCanine  Ballard’sBallard’s  Salzmann’sSalzmann’s  Ackerman-Profit SystemAckerman-Profit System  Katz’sKatz’s  Beat’sBeat’s www.indiandentalacademy.comwww.indiandentalacademy.com
  3. 3.  IntroductionIntroduction Orthodontics has been described as a “Science of infinite variations” byOrthodontics has been described as a “Science of infinite variations” by Jackson. In order to aquire a better understanding of many deviations fromJackson. In order to aquire a better understanding of many deviations from normal occlusion it becomes necessary to group the varieties ofnormal occlusion it becomes necessary to group the varieties of malocclusion into order.malocclusion into order.  DefinitionDefinition Malocclusion may be defined as ‘any variation or deviation from theMalocclusion may be defined as ‘any variation or deviation from the normal occlusion’.normal occlusion’. OROR ‘‘A condition where there is departure from the normal relation of the teethA condition where there is departure from the normal relation of the teeth to other teeth in the same arch and to the teeth in the opposing arch’.to other teeth in the same arch and to the teeth in the opposing arch’. (WHITE GARDNER).(WHITE GARDNER). Malocclusion can present itself in numerous ways.Malocclusion can present itself in numerous ways. www.indiandentalacademy.comwww.indiandentalacademy.com
  4. 4.  Classification :Classification : involves the grouping together ofinvolves the grouping together of various malocclusion into simpler or smaller groups.various malocclusion into simpler or smaller groups. In order to have a system of classification, standardIn order to have a system of classification, standard should be set up that represent normally. Theshould be set up that represent normally. The deviation from the norms should also be grouped intodeviation from the norms should also be grouped into various smaller divisions or categories.various smaller divisions or categories.  ClassificationClassification is a vital element in the diagnosisis a vital element in the diagnosis of a malocclusion and in treatment planning forof a malocclusion and in treatment planning for orthodontic care. An ideal classification wouldorthodontic care. An ideal classification would summerise the diagnostic data and imply thesummerise the diagnostic data and imply the treatment plan.treatment plan. www.indiandentalacademy.comwww.indiandentalacademy.com
  5. 5.  HISTORYHISTORY  Hippocrates included “Crooked teeth” in his 6th book of epidemies asHippocrates included “Crooked teeth” in his 6th book of epidemies as early as 24th centuries ago.early as 24th centuries ago.  What we today call normal occlusion was described as early as 18thWhat we today call normal occlusion was described as early as 18th century by John Hunter.century by John Hunter.  Carabelli in the mid 19th century was probably the 1st person toCarabelli in the mid 19th century was probably the 1st person to describe in any systematic way the abnormal relationships of upper anddescribe in any systematic way the abnormal relationships of upper and lower dental arches. The terms “edge to edge” and “overbite” are actuallylower dental arches. The terms “edge to edge” and “overbite” are actually derived from carabellis system of classification.derived from carabellis system of classification.  Edward Angle in 1899 introduced his classification of malocclusionEdward Angle in 1899 introduced his classification of malocclusion bared on the relative position of the 1st molars. This classification wasbared on the relative position of the 1st molars. This classification was readily accepted by the dental profession since it brought order out of whatreadily accepted by the dental profession since it brought order out of what previously had been confusion regarding dental relationshipspreviously had been confusion regarding dental relationships www.indiandentalacademy.comwww.indiandentalacademy.com
  6. 6.  Calvin case criticized Angle classification and introduced hisCalvin case criticized Angle classification and introduced his modification, so e divided.modification, so e divided.  Class I into – Division I with seven subtypes.Class I into – Division I with seven subtypes.  - Division II for facial considerations- Division II for facial considerations  Class II into – Division I cases in which the mandible retrusiveClass II into – Division I cases in which the mandible retrusive  Division II cases in which the mandible was protrusiveDivision II cases in which the mandible was protrusive  Class II into four division that described combination ofClass II into four division that described combination of maxillary retrusion and mandibular protrusion.maxillary retrusion and mandibular protrusion.  Inspite of all this, angles classification remains standardInspite of all this, angles classification remains standard while cases superior efforts never become popular which waswhile cases superior efforts never become popular which was unfortunate result of the personality cut that surrounded earlyunfortunate result of the personality cut that surrounded early orthodontic giants.orthodontic giants. www.indiandentalacademy.comwww.indiandentalacademy.com
  7. 7.  Then came Dewey an early student of Angle and thenThen came Dewey an early student of Angle and then a fellow teacher wrote in 1915 “I have great respecta fellow teacher wrote in 1915 “I have great respect for the 1st molars as an organ of mastication, andfor the 1st molars as an organ of mastication, and they are very necessary in producing normalthey are very necessary in producing normal occlusion, but as a basis of classification, when takenocclusion, but as a basis of classification, when taken alone I have not much respect for them, as they are asalone I have not much respect for them, as they are as liable as any other teeth to liable as any other teeth toliable as any other teeth to liable as any other teeth to assume an abnormal position under certain condition.assume an abnormal position under certain condition. Dewey recommended that classification be bared onDewey recommended that classification be bared on the anteroposterior relation of the arches as a wholethe anteroposterior relation of the arches as a whole rather than only the 1st molars. Dewy sub-classifiedrather than only the 1st molars. Dewy sub-classified class I into three types and Anderson later added twoclass I into three types and Anderson later added two more.more. www.indiandentalacademy.comwww.indiandentalacademy.com
  8. 8.  In 1920 Hellman stated “In all its simplicity the angleIn 1920 Hellman stated “In all its simplicity the angle classification does not convey exactly the same idea toclassification does not convey exactly the same idea to everyone. This is perhaps due to that fact that its definition iseveryone. This is perhaps due to that fact that its definition is not sufficiently accurate. He recommended elimination ofnot sufficiently accurate. He recommended elimination of buccal cusp relationship as the forces of classification to thebuccal cusp relationship as the forces of classification to the mesiolingual cusp of maxillary 1st molar as the focus formesiolingual cusp of maxillary 1st molar as the focus for classification. Hellman considered this mesio lingual cusp toclassification. Hellman considered this mesio lingual cusp to be the only reliable distinguishing feature.be the only reliable distinguishing feature.  Bennett was a precursor of Simon when in 1912, heBennett was a precursor of Simon when in 1912, he recommended classifying Malocclusion in sagittal transverserecommended classifying Malocclusion in sagittal transverse and vertical planes of spaces.and vertical planes of spaces.  Bennet developed a classification that also uses class I, IIBennet developed a classification that also uses class I, II and III, but he divided malocclusion by etiology rather thanand III, but he divided malocclusion by etiology rather than morphology.morphology. www.indiandentalacademy.comwww.indiandentalacademy.com
  9. 9.  Simon in 1920 put forward a craniometric classification ofSimon in 1920 put forward a craniometric classification of malocclusion that related the dental arches in all three planesmalocclusion that related the dental arches in all three planes ie., Frank fort horizontal plane, orbital plane and mid sagittalie., Frank fort horizontal plane, orbital plane and mid sagittal plane.plane.  In 1928 strong felt strongly that the process classificationIn 1928 strong felt strongly that the process classification includeinclude  Inclined plane relationships.Inclined plane relationships.  The axial inclination of each toothThe axial inclination of each tooth  A frontal analysis of midline deviations.A frontal analysis of midline deviations.  Possible asymmetric condylar positions.Possible asymmetric condylar positions.  Rotations of posterior teethRotations of posterior teeth  Facial and skeletal considerations using photographs andFacial and skeletal considerations using photographs and cephalometric radiographs.cephalometric radiographs. www.indiandentalacademy.comwww.indiandentalacademy.com
  10. 10.  In 1969 Ackerman proposed a diagrammatic classification ofIn 1969 Ackerman proposed a diagrammatic classification of malocclusion to overcome the limitations of the anglesmalocclusion to overcome the limitations of the angles classification. This systems of classification in based in Vennclassification. This systems of classification in based in Venn symbolis diagram that identifies five major characteristics i.e,symbolis diagram that identifies five major characteristics i.e,  Alignment in occlusion viewAlignment in occlusion view  Profile and soft tissueProfile and soft tissue  Transverse plane deviationTransverse plane deviation  Sagittal plane deviationSagittal plane deviation  Vertical plane deviationVertical plane deviation  Now a day its almost 100 years since Angle had introduced hisNow a day its almost 100 years since Angle had introduced his method of classification. Then came so many modification,method of classification. Then came so many modification, but inspite of all this Angles classification is still in usebut inspite of all this Angles classification is still in use because of its simplicity in application.because of its simplicity in application. www.indiandentalacademy.comwww.indiandentalacademy.com
  11. 11.  PURPOSE OF CLASSIFYING MALOCCLUSIONPURPOSE OF CLASSIFYING MALOCCLUSION  The following are the purpose for which we need to classify.The following are the purpose for which we need to classify.  To identify the problem (Diagnosis)To identify the problem (Diagnosis)  For better treatment planningFor better treatment planning  Alterourselves to possible strategies and appliances, that may be needed inAlterourselves to possible strategies and appliances, that may be needed in treatment.treatment.  Recalling pass difficulties with similar cases.Recalling pass difficulties with similar cases.  For the purpose of comparisonFor the purpose of comparison  Ease of reference andEase of reference and  For communicationFor communication  TYPES OF MALOCCLUSIONTYPES OF MALOCCLUSION  Malocclusion can be broadly divided intoMalocclusion can be broadly divided into  Individual teeth mal position or intra arch malocclusionIndividual teeth mal position or intra arch malocclusion  Mal relation of dental arches :- to one another upon bony bases which mayMal relation of dental arches :- to one another upon bony bases which may themselves be normally related.themselves be normally related.  Skeletal malocclusions which involve the underlying bony bases.Skeletal malocclusions which involve the underlying bony bases. www.indiandentalacademy.comwww.indiandentalacademy.com
  12. 12.  INDIVIDUAL TEETH MALPOSITIONSINDIVIDUAL TEETH MALPOSITIONS  A tooth can be abnormally related to itsA tooth can be abnormally related to its neighboring teeth. Such abnormal variations areneighboring teeth. Such abnormal variations are called individual teeth malposition or intra archcalled individual teeth malposition or intra arch malocclusion. The individual teeth malposition canmalocclusion. The individual teeth malposition can be abnormal inclination (or tipping) of the teeth orbe abnormal inclination (or tipping) of the teeth or abnormal displacements. Abnormal inclinationabnormal displacements. Abnormal inclination involves the abnormal tilting of the crown, with theinvolves the abnormal tilting of the crown, with the root being in normal position. Bodily displacementroot being in normal position. Bodily displacement involves abnormal location of the crown asinvolves abnormal location of the crown as www.indiandentalacademy.comwww.indiandentalacademy.com
  13. 13.  TYPES OF MALOCCLUSIONTYPES OF MALOCCLUSION  3 TYPES3 TYPES  Individual teeth Mal positionIndividual teeth Mal position  Mal relation of dental arches to one anotherMal relation of dental arches to one another  Skeletal malocclusionsSkeletal malocclusions  Individual tooth MalpositionsIndividual tooth Malpositions A tooth can be abnormally related to its neighbouring teeth.such abnormalA tooth can be abnormally related to its neighbouring teeth.such abnormal variations are called individual teeth malposition or intra archvariations are called individual teeth malposition or intra arch malocclsions. The individual teeth malposition can be abnormalmalocclsions. The individual teeth malposition can be abnormal incllination of the teeth or abnormal displacements. Abnormal inclinationincllination of the teeth or abnormal displacements. Abnormal inclination involves abnormal tilting of the crown, with the root being in normalinvolves abnormal tilting of the crown, with the root being in normal position. Bodily displacement involves abnormal location of the crown asposition. Bodily displacement involves abnormal location of the crown as well as root in the same direction.some of the commonly seen individualwell as root in the same direction.some of the commonly seen individual teeth malpositions areteeth malpositions are www.indiandentalacademy.comwww.indiandentalacademy.com
  14. 14.  DISTAL INCLINATION FOR DISTAL TIPPING :DISTAL INCLINATION FOR DISTAL TIPPING : this refers to athis refers to a conditions where the crown of the tooth is tilted or inclined distally.conditions where the crown of the tooth is tilted or inclined distally.  MESIAL INCLINATION OR MESIAL TIPPING :MESIAL INCLINATION OR MESIAL TIPPING : This is a conditionThis is a condition where the crown of the tooth is tilted or inclined mesially.where the crown of the tooth is tilted or inclined mesially.  LINGUAL INCLINATION OR LINGUAL TIPPING :LINGUAL INCLINATION OR LINGUAL TIPPING : This is anThis is an abnormal lingual or palatal tilting of the tooth. This condition is also calledabnormal lingual or palatal tilting of the tooth. This condition is also called retroclination.retroclination.  BUCCAL INCLINATION OR BUCCAL TIPPING :BUCCAL INCLINATION OR BUCCAL TIPPING : This refers toThis refers to labial (in case of anterior) or buccal (in case of posterior) tilting of thelabial (in case of anterior) or buccal (in case of posterior) tilting of the tooth. This condition is also called proclination.tooth. This condition is also called proclination.  MESIAL DISPLACEMENT :MESIAL DISPLACEMENT : This refers to a tooth that is bodily movedThis refers to a tooth that is bodily moved in a mesial direction towards the midline.in a mesial direction towards the midline. www.indiandentalacademy.comwww.indiandentalacademy.com
  15. 15.  DISTAL DISPLACEMENT :DISTAL DISPLACEMENT : this refers to a tooth that isthis refers to a tooth that is bodily moved in a distal direction away from the midline.bodily moved in a distal direction away from the midline.  LINGUAL DISPLACEMENT :LINGUAL DISPLACEMENT : this is a conditions wherethis is a conditions where the entire tooth is displacement in a lingual direction.the entire tooth is displacement in a lingual direction.  BUCCAL DISPLACEMENT :BUCCAL DISPLACEMENT : This describes a conditionThis describes a condition where the tooth is displaced bodily in a labial or buccalwhere the tooth is displaced bodily in a labial or buccal directiondirection  INFRA VERSION OR INFRA OCCLUSION :INFRA VERSION OR INFRA OCCLUSION : the termsthe terms infraversion or infraocclusion refer to a tooth that has notinfraversion or infraocclusion refer to a tooth that has not erupted enough compared to the other teeth in the arch.erupted enough compared to the other teeth in the arch.  SUPRAVERSION OR SUPRA OCCLUSIONSUPRAVERSION OR SUPRA OCCLUSION : This is a: This is a tooth that has over erupted as compared to other teeth in thetooth that has over erupted as compared to other teeth in the arch. It is also called supra occlusion.arch. It is also called supra occlusion. www.indiandentalacademy.comwww.indiandentalacademy.com
  16. 16.  Rotations :Rotations : this term refers to tooth movementsthis term refers to tooth movements around its long axis.around its long axis.  DISTO-LINGUAL OR MESIO-BUCCALDISTO-LINGUAL OR MESIO-BUCCAL ROTATION :ROTATION : this describes a tooth which hasthis describes a tooth which has moved around its long axis so that the distal aspect ismoved around its long axis so that the distal aspect is more lingually placed.more lingually placed.  MESIO LINGUAL OR DISTO – BUCCALMESIO LINGUAL OR DISTO – BUCCAL ROTATION :ROTATION : this is a condition where the tooth hasthis is a condition where the tooth has rotated around its long axis so that the mesial aspectrotated around its long axis so that the mesial aspect is more lingually placed.is more lingually placed.  TRANSPOSITION :TRANSPOSITION : This term describes aThis term describes a condition where two teeth have exchanged places.condition where two teeth have exchanged places. www.indiandentalacademy.comwww.indiandentalacademy.com
  17. 17.  MAXILLO-MANDIBULAR MALOCCLUSIONSMAXILLO-MANDIBULAR MALOCCLUSIONS  These malocclusions are characterized by abnormalThese malocclusions are characterized by abnormal relationship between two teeth or groups of teeth of one archrelationship between two teeth or groups of teeth of one arch to the other arch. These inter-arch malocclusions can occur into the other arch. These inter-arch malocclusions can occur in the sagittal, vertical or in the transverse planes of space.the sagittal, vertical or in the transverse planes of space.  SAGITTAL PLANE MALOCCLUSIONSSAGITTAL PLANE MALOCCLUSIONS  Pre-normal occlusionPre-normal occlusion  This term refers to a condition where the lower arch isThis term refers to a condition where the lower arch is more forwardly placed when the patient bites in centricmore forwardly placed when the patient bites in centric occlusion.occlusion.  Post-Normal occlusionPost-Normal occlusion  This is a condition where the lower arch is more distallyThis is a condition where the lower arch is more distally placed when the patient bites in centric occlusion.placed when the patient bites in centric occlusion. www.indiandentalacademy.comwww.indiandentalacademy.com
  18. 18.  Vertical Plane malocclusionsVertical Plane malocclusions  Deep bite or increased over biteDeep bite or increased over bite  This refers to a condition where there is an excessiveThis refers to a condition where there is an excessive vertical overlap between the upper and lower anterior teeth.vertical overlap between the upper and lower anterior teeth.  Open bite :Open bite : This is a condition where there is no verticalThis is a condition where there is no vertical overlap between the upper and lower teeth. Thus a space mayoverlap between the upper and lower teeth. Thus a space may exist between the upper and lower teeth when the patient bitesexist between the upper and lower teeth when the patient bites in centric occlusion. The open bites in centric occlusion. Thein centric occlusion. The open bites in centric occlusion. The open bite can be in the anterior or the posterior region.open bite can be in the anterior or the posterior region. Transverse plane malocclusions :Transverse plane malocclusions : The transverse plane interThe transverse plane inter arch malocclusion includes various types of cross bites. Termarch malocclusion includes various types of cross bites. Term cross bite refers to abnormal transverse relationship betweencross bite refers to abnormal transverse relationship between the upper and lower arches.the upper and lower arches.  www.indiandentalacademy.comwww.indiandentalacademy.com
  19. 19.  ANGLES SYSTEM OF CLASSIFICATIONANGLES SYSTEM OF CLASSIFICATION  Edward Angle the “Father of Modern Orthodontics” introduced aEdward Angle the “Father of Modern Orthodontics” introduced a system of classifying malocclusion in the year 1899. Angles classificationsystem of classifying malocclusion in the year 1899. Angles classification is still in use after almost 100 years of its introduction due to its simplicityis still in use after almost 100 years of its introduction due to its simplicity in application.in application.  Basis for Angle’s ClassificationBasis for Angle’s Classification  Angles classification was based on the mesiodistal relation of the teeth,Angles classification was based on the mesiodistal relation of the teeth, dental arches and the jaws.dental arches and the jaws.  According to Angle, the maxillary 1st permanent molar is the key toAccording to Angle, the maxillary 1st permanent molar is the key to occlusion. He considered there teeth as fixed anatomical points within theocclusion. He considered there teeth as fixed anatomical points within the jaws.jaws.  Based on the relation of the lower 1st permanent molar to the upper 1stBased on the relation of the lower 1st permanent molar to the upper 1st permanent molar he classified mal occlusions into three main classespermanent molar he classified mal occlusions into three main classes designated by the Roman numerals I, II & III.designated by the Roman numerals I, II & III. www.indiandentalacademy.comwww.indiandentalacademy.com
  20. 20.  ANGLE’S CLASS IANGLE’S CLASS I  Angle’s Class I malocclusion is characterized by the presence ofAngle’s Class I malocclusion is characterized by the presence of normal inter arch molar relation. Approximately 60-70% of all cases ofnormal inter arch molar relation. Approximately 60-70% of all cases of malocclusions full in this class.malocclusions full in this class.  There patient exhibit normal skeletal relations and show normalThere patient exhibit normal skeletal relations and show normal muscle function.muscle function.  Here the mesiobuccal cusp of the maxillary 1st permanent molarHere the mesiobuccal cusp of the maxillary 1st permanent molar occludes in the buccal groove of mandibular 1st permanent molar.occludes in the buccal groove of mandibular 1st permanent molar.  Along with this the patient may exhibit irregularities such asAlong with this the patient may exhibit irregularities such as crowding, spacing, rotations, mixing tooth etc.crowding, spacing, rotations, mixing tooth etc.  Another malocclusions that is most often categorized under class I isAnother malocclusions that is most often categorized under class I is Class I Bimaxillary protrusions.Class I Bimaxillary protrusions.  In this case the patient exhibits a normal class I molar relationship butIn this case the patient exhibits a normal class I molar relationship but the dentition of both the upper and lower arches are forwardly placed inthe dentition of both the upper and lower arches are forwardly placed in relation to the facial profile.relation to the facial profile. www.indiandentalacademy.comwww.indiandentalacademy.com
  21. 21.  ANGLE’S CLASS IIANGLE’S CLASS II  This group is characterized by a Class II molar relation where theThis group is characterized by a Class II molar relation where the mesiobuccal cusps of the upper 1st permanent molar occludes in the buccalmesiobuccal cusps of the upper 1st permanent molar occludes in the buccal groove of the lower 1st permanent molar.groove of the lower 1st permanent molar.  Angle has sub divided class II malocclusions into two divisionsAngle has sub divided class II malocclusions into two divisions  Div. IDiv. I  Div. IIDiv. II  Class II Div.1: A malocclusion is characterized byClass II Div.1: A malocclusion is characterized by  PROCLINED :PROCLINED : Upper incisors with resultant increase in overjetUpper incisors with resultant increase in overjet  A deep incisorA deep incisor OVER BITEOVER BITE can occur in the ant region.can occur in the ant region.  A characteristic feature of this malocclusions is the presence of abnormalA characteristic feature of this malocclusions is the presence of abnormal muscle activity.muscle activity.  The upper lip is usually hypotonic, short and fails to form a lip seal.The upper lip is usually hypotonic, short and fails to form a lip seal. www.indiandentalacademy.comwww.indiandentalacademy.com
  22. 22.  The lower lip cushions the palatal aspect of the upper teeth, aThe lower lip cushions the palatal aspect of the upper teeth, a feature typical of a class II Div 1 referred to as “lip trap”.feature typical of a class II Div 1 referred to as “lip trap”.  The Tongue occupies a lower position thereby failing toThe Tongue occupies a lower position thereby failing to counter act the buccinator activity.counter act the buccinator activity.  The unrestrained Buccinator activity results in narrowing ofThe unrestrained Buccinator activity results in narrowing of the upper arch at the premolar and canine regions therebythe upper arch at the premolar and canine regions thereby producing a “V” shaped upper arch.producing a “V” shaped upper arch.  Another muscle aberration is a hyper active mentalis activity .Another muscle aberration is a hyper active mentalis activity . the muscle imbalance is produced by a hyper active buccinatorthe muscle imbalance is produced by a hyper active buccinator and mentalis and an altered tongue position that accentuatesand mentalis and an altered tongue position that accentuates the narrowing of the upper dental arch.the narrowing of the upper dental arch. www.indiandentalacademy.comwww.indiandentalacademy.com
  23. 23.  Class II Div. 2 :Class II Div. 2 :  As in Class II Div I malocclusion, the Div 2 also exhibitsAs in Class II Div I malocclusion, the Div 2 also exhibits a Class II molar relationship.a Class II molar relationship.  The classic feature of this malocclusion is the presence ofThe classic feature of this malocclusion is the presence of lingually inclined upper central incisors and labially tippedlingually inclined upper central incisors and labially tipped upper lateral incisors overlapping the central incisors.upper lateral incisors overlapping the central incisors.  Variations of this form are lingually inclined central andVariations of this form are lingually inclined central and lateral incisors with the canines labially tipped.lateral incisors with the canines labially tipped.  Along with this the patient exhibitsAlong with this the patient exhibits DEEP ANTERIORDEEP ANTERIOR OVERBITEOVERBITE  Some of the other features areSome of the other features are www.indiandentalacademy.comwww.indiandentalacademy.com
  24. 24.  Due to lingually inclined upper centrals. It givesDue to lingually inclined upper centrals. It gives the arch a squarish appearancethe arch a squarish appearance  Mandibular labial gingival tissue is oftenMandibular labial gingival tissue is often traumatized by the excessively tipped uppertraumatized by the excessively tipped upper central incisors.central incisors.  The patient exhibits normal perioral muscleThe patient exhibits normal perioral muscle activity.activity.  An abnormal backward path of closure may alsoAn abnormal backward path of closure may also be present due to the excessively tipped centralbe present due to the excessively tipped central incisors.incisors. www.indiandentalacademy.comwww.indiandentalacademy.com
  25. 25.  Class II sub divisionClass II sub division  When a class II molar relations exists on one side and aWhen a class II molar relations exists on one side and a class I relation on the other, it is referred to as Class IIclass I relation on the other, it is referred to as Class II subdivision.subdivision.  Based on wheather it is a Div. 1 or Divi. 2 it can be calledBased on wheather it is a Div. 1 or Divi. 2 it can be called Class II Div. 1 subdivision or Class II Div. II Subdivision.Class II Div. 1 subdivision or Class II Div. II Subdivision.  ANGLE’S CLASS IIIANGLE’S CLASS III  This malocclusions exhibits class III molar relationship.This malocclusions exhibits class III molar relationship. i.e. Mesiobuccal cusp of the maxillary 1st permanent molari.e. Mesiobuccal cusp of the maxillary 1st permanent molar occludes in the inter dental space between the mandibular 1stoccludes in the inter dental space between the mandibular 1st and second molars.and second molars.  This can be again classified intoThis can be again classified into  True Class III and Pseudo Class IIITrue Class III and Pseudo Class III www.indiandentalacademy.comwww.indiandentalacademy.com
  26. 26.  True Class IIITrue Class III  Is skeletal Class III malocclusions of genetic origin that can occur due toIs skeletal Class III malocclusions of genetic origin that can occur due to following causes.following causes.  Excessively large mandible.Excessively large mandible.  Prognathic mandiblePrognathic mandible  Smaller than normal MaxillaSmaller than normal Maxilla  Retroposition maxillaRetroposition maxilla  Combination of the above causes.Combination of the above causes.  Some of the features areSome of the features are  The lower incisors tend to be lingually inclinedThe lower incisors tend to be lingually inclined  The patient can present with -> Normal overjet.The patient can present with -> Normal overjet.  -> Edge to edge incisor relations-> Edge to edge incisor relations  oror  -> An anterior cross-> An anterior cross bite.bite.  The space available for the tongue is usually more. Thus the tongue occupies aThe space available for the tongue is usually more. Thus the tongue occupies a lower position, resulting in a narrow upper arch.lower position, resulting in a narrow upper arch. www.indiandentalacademy.comwww.indiandentalacademy.com
  27. 27.  Pseudo Class III :Pseudo Class III :  This type of malocclusions is produced by forward movement of theThis type of malocclusions is produced by forward movement of the mandible during jaw closure, thus it is also called.mandible during jaw closure, thus it is also called.  Postural Class III Malocclusions or Habitual Class III malocclusionsPostural Class III Malocclusions or Habitual Class III malocclusions  Presence of occlusal prematureties may deflect the mandible forward.Presence of occlusal prematureties may deflect the mandible forward.  In case of premature loss of deciduous posteriors, the child tends to moreIn case of premature loss of deciduous posteriors, the child tends to more his mandible forward to establish contact in the anterior region.his mandible forward to establish contact in the anterior region.  A child with enlarged adnoids tends to more the mandible forward in anA child with enlarged adnoids tends to more the mandible forward in an attempt to present the tongue from contacting the adenoidsattempt to present the tongue from contacting the adenoids  CLASS III SUBDIVISIONCLASS III SUBDIVISION  This is characterized by a class III molar relations on one side and aThis is characterized by a class III molar relations on one side and a class I relation on the other side.class I relation on the other side. www.indiandentalacademy.comwww.indiandentalacademy.com
  28. 28.  DRAWBACKS OF ANGLE’SDRAWBACKS OF ANGLE’S CLASSIFICATIONCLASSIFICATION  Although Angle’s classification has been used forAlthough Angle’s classification has been used for almost a hundred years now, it still has a no ofalmost a hundred years now, it still has a no of drawbacks,drawbacks,  That includesThat includes  Angle considered malocclusion only in the anterior-Angle considered malocclusion only in the anterior- posterior plane. He did not consider malocclusions inposterior plane. He did not consider malocclusions in the transverse and vertical planes.the transverse and vertical planes.  Angle considered the 1st permanent molars as fixedAngle considered the 1st permanent molars as fixed points in the skull, but this is not found to be so.points in the skull, but this is not found to be so. www.indiandentalacademy.comwww.indiandentalacademy.com
  29. 29.  The classification cannot be applied if the 1stThe classification cannot be applied if the 1st permanent molars are extracted or missing.permanent molars are extracted or missing.  The classification cannot be applied to the deciduousThe classification cannot be applied to the deciduous dentition.dentition.  The classification does not differentiate betweenThe classification does not differentiate between skeletal and dental malocclusions.skeletal and dental malocclusions.  The classifications does not high light the etiology ofThe classifications does not high light the etiology of the malocclusionthe malocclusion  individual tooth malpositions have not beenindividual tooth malpositions have not been considered by Angle.considered by Angle. www.indiandentalacademy.comwww.indiandentalacademy.com
  30. 30.  DEWEY’S MODIFICATION OF ANGLE’S MALOCCLUSIONDEWEY’S MODIFICATION OF ANGLE’S MALOCCLUSION  Dewey an early student of angle then a fellow teacher in 1915Dewey an early student of angle then a fellow teacher in 1915 proposed a modification of the angle’s classification of malocclusion.proposed a modification of the angle’s classification of malocclusion.  He divided Angle’s Class I into five types andHe divided Angle’s Class I into five types and  Angle’s Class III into three types.Angle’s Class III into three types.  Class I modification of DeweyClass I modification of Dewey  Type I :Type I : Class I malocclusion with bunched and crowded anterior teethClass I malocclusion with bunched and crowded anterior teeth  Type II :Type II : Class I malocclusion with protrusive maxillary incisors.Class I malocclusion with protrusive maxillary incisors.  Type III :Type III : Class I malocclusion with anterior cross biteClass I malocclusion with anterior cross bite  Type IV :Type IV : Class I molar relations with posterior cross biteClass I molar relations with posterior cross bite  Type V :Type V : The permanent molar has drifted mesially due to earlyThe permanent molar has drifted mesially due to early extractionextraction  of secondof second deridiansderidians molar or 2nd premolar.molar or 2nd premolar. www.indiandentalacademy.comwww.indiandentalacademy.com
  31. 31.  Class III modification of DeweyClass III modification of Dewey  Type I :Type I : the upper and lower dental arches whenthe upper and lower dental arches when viewed separately are in normal alignment. But whenviewed separately are in normal alignment. But when the arches are made to occlude the patient shows anthe arches are made to occlude the patient shows an edge to edge incisors alignment suggestive of aedge to edge incisors alignment suggestive of a forwardly moved mandibular dental arch.forwardly moved mandibular dental arch.  Type II :Type II : The mandibular incisor are crowded andThe mandibular incisor are crowded and are in lingual relation to the maxillary incisors.are in lingual relation to the maxillary incisors.  Type III :Type III : The maxillary incisors are crowded andThe maxillary incisors are crowded and are in cross bite in relations to the mandibularare in cross bite in relations to the mandibular anteriors.anteriors. www.indiandentalacademy.comwww.indiandentalacademy.com
  32. 32.  LISCHER’S MODIFICATIONS OF ANGLE’S CLASSIFICATIONLISCHER’S MODIFICATIONS OF ANGLE’S CLASSIFICATION  Lisher in 1933 substituted the term class I, II, III given an Angle withLisher in 1933 substituted the term class I, II, III given an Angle with the termthe term Neutro occlusionsNeutro occlusions  Distooclusions andDistooclusions and  MesioocclusionMesioocclusion  He introduced the suffix “Version” to describe the malposition ofHe introduced the suffix “Version” to describe the malposition of individual teeth.individual teeth.  Bucco VersionsBucco Versions -- Buccally placed tooth or group of teethBuccally placed tooth or group of teeth  Lingually Versions -Lingually Versions - Lingually placed tooth or group of teethLingually placed tooth or group of teeth  Mesio VersionsMesio Versions -- Mesially placed tooth or group of teethMesially placed tooth or group of teeth  Disto VersionsDisto Versions -- Distally placed tooth or group of teethDistally placed tooth or group of teeth  Supra VersionsSupra Versions -- Superiorly placed tooth or group of teethSuperiorly placed tooth or group of teeth  Torsi VersionsTorsi Versions -- Rotation of tooth or group of teethRotation of tooth or group of teeth  Transi VersionsTransi Versions -- Transposition of 2 teeth.Transposition of 2 teeth. www.indiandentalacademy.comwww.indiandentalacademy.com
  33. 33.  HELMAN’S CLASSIFICATIONHELMAN’S CLASSIFICATION  In 1920 Helman’s stated that in all its simplicity the Angle’s ClassificationsIn 1920 Helman’s stated that in all its simplicity the Angle’s Classifications do not convey exactly the same idea to everyone. “This is perhaps due to the factdo not convey exactly the same idea to everyone. “This is perhaps due to the fact that its definition is not sufficiently accurate”.that its definition is not sufficiently accurate”.  He recommended elimination of the buccal cusp relationship as the focus ofHe recommended elimination of the buccal cusp relationship as the focus of classification.classification.  Hallmen considered the mesiolingual cusp to be the only reliableHallmen considered the mesiolingual cusp to be the only reliable distinguishing feature, because it was the most premitrive of occlusion still retaineddistinguishing feature, because it was the most premitrive of occlusion still retained by modern man.by modern man.  The mesiolingual cusp of the max 1st occludes in the central fossa of the 1stThe mesiolingual cusp of the max 1st occludes in the central fossa of the 1st mandibulr molar.mandibulr molar.  He observed in the high percentage of molars that the max. 1st molar hasHe observed in the high percentage of molars that the max. 1st molar has rotated on the longitudinal axis of the lingual cusp and the buccal cusps has rotatedrotated on the longitudinal axis of the lingual cusp and the buccal cusps has rotated mesially.mesially.  The mesially rotated maxillary buccal cusps falsely indicated a class IIThe mesially rotated maxillary buccal cusps falsely indicated a class II occlusion, while the more “premitive” maxillary mesio lingual cusp sat in its idealocclusion, while the more “premitive” maxillary mesio lingual cusp sat in its ideal class I position.class I position. www.indiandentalacademy.comwww.indiandentalacademy.com
  34. 34.  SIMON’S CLASSIFICATIONSIMON’S CLASSIFICATION  In 1920 Simon of Berlin developed aIn 1920 Simon of Berlin developed a gnathostatic system using a elaborate facebowgnathostatic system using a elaborate facebow and impression orienting apparatus to createand impression orienting apparatus to create study models that were cephalometricallystudy models that were cephalometrically oriented to the patient orbital plane.oriented to the patient orbital plane.  He put forward a craniometricHe put forward a craniometric classification of malocclusion that related theclassification of malocclusion that related the dental arches in all three planes.dental arches in all three planes. www.indiandentalacademy.comwww.indiandentalacademy.com
  35. 35.  Simon’s system of classification made use ofSimon’s system of classification made use of three anthropometric planes i.e :three anthropometric planes i.e :  Frankfort horizontal planeFrankfort horizontal plane  Orbital plane andOrbital plane and  Mid sagittal planeMid sagittal plane  The classification of malocclusion was basedThe classification of malocclusion was based on abnormal deviations of the dental arch fromon abnormal deviations of the dental arch from their normal position in relation to these threetheir normal position in relation to these three planes.planes. www.indiandentalacademy.comwww.indiandentalacademy.com
  36. 36.  FRANKFORT HORIZONTAL PLANEFRANKFORT HORIZONTAL PLANE  This is a plane that connects the upper margins ofThis is a plane that connects the upper margins of the auditory meatus to the infra orbital margin. Thisthe auditory meatus to the infra orbital margin. This plane is used to classify malocclusions in a verticalplane is used to classify malocclusions in a vertical plane. Two terms are used to describe any abnormalplane. Two terms are used to describe any abnormal relations of the teeth to this plane.relations of the teeth to this plane.  When the dental arch or part of it is closer thanWhen the dental arch or part of it is closer than normal to the Frankfort plane it is callednormal to the Frankfort plane it is called ATTRACTION.ATTRACTION.  When the dental arch or part of it is further awayWhen the dental arch or part of it is further away from the Frankfort plane it is calledfrom the Frankfort plane it is called ABSTRACTION.ABSTRACTION. www.indiandentalacademy.comwww.indiandentalacademy.com
  37. 37.  ORBITAL PLANEORBITAL PLANE  This plane is pependicular to the Frankfort horizontalThis plane is pependicular to the Frankfort horizontal plans dropped down from the bony orbital margin directlyplans dropped down from the bony orbital margin directly under the pupil of the eye.under the pupil of the eye.  According to simon, this plane should pass through theAccording to simon, this plane should pass through the distal third of the canine. This is called Simon’s low of canine.distal third of the canine. This is called Simon’s low of canine.  This plane is used to describe malocclusion in a sagittal orThis plane is used to describe malocclusion in a sagittal or anteroposterior direction. When the dental arch or part of it isanteroposterior direction. When the dental arch or part of it is further from the orbital plane it is called protraction.further from the orbital plane it is called protraction.  When the arch or part of it is closer or more posteriorlyWhen the arch or part of it is closer or more posteriorly placed in relations to this plane. It is called retraction.placed in relations to this plane. It is called retraction. www.indiandentalacademy.comwww.indiandentalacademy.com
  38. 38.  MID SAGITTAL – PLANEMID SAGITTAL – PLANE  The mid sagittal plane is used to describeThe mid sagittal plane is used to describe malocclusions in the transverse directions. When amalocclusions in the transverse directions. When a part of the arch or the whole arch is away from midpart of the arch or the whole arch is away from mid sagittal mal it is calledsagittal mal it is called DISTRACTIONDISTRACTION  When the arch or part of its is closer to the mid-When the arch or part of its is closer to the mid- sagittal plane it is calledsagittal plane it is called CONTRACTION.CONTRACTION.  Its application to clinical situations is notIts application to clinical situations is not practicalpractical  DRAWBACKS :DRAWBACKS : research has proved his low ofresearch has proved his low of canine to be wrong.canine to be wrong. www.indiandentalacademy.comwww.indiandentalacademy.com
  39. 39.  BENNETT’S CLASSIFICATIONBENNETT’S CLASSIFICATION  Norman Bennett was a precursor of simon when in 1912Norman Bennett was a precursor of simon when in 1912 be recommended classifying malocclusions in three planes ofbe recommended classifying malocclusions in three planes of space sagittal, transverse and vertical planes. Bennet onspace sagittal, transverse and vertical planes. Bennet on Englishman, developed a classification that also uses, class I,Englishman, developed a classification that also uses, class I, II & III but he divides malocclusions byII & III but he divides malocclusions by ETIOLOGYETIOLOGY ratherrather than morphologythan morphology  Class I :Class I : Abnormal position of one or more teeth due to localAbnormal position of one or more teeth due to local causes.causes.  Class II :Class II : Abnormal formation of a part or whole of eitherAbnormal formation of a part or whole of either arch due to development defects of bone.arch due to development defects of bone.  Class III :Class III : Abnormal relationships between upper and lowerAbnormal relationships between upper and lower arches and between either arch and facial contour andarches and between either arch and facial contour and correlated abnormal formation of either arch.correlated abnormal formation of either arch. www.indiandentalacademy.comwww.indiandentalacademy.com
  40. 40.  INCISOR CLASSIFICATION (MILLS)INCISOR CLASSIFICATION (MILLS)  This is also called the British Standard classifications ofThis is also called the British Standard classifications of incisors relationship.incisors relationship.  Incisors are classified into 3 class under thisIncisors are classified into 3 class under this classification.classification.  They areThey are  Class I :Class I : the lower incisal edges occlude with or liethe lower incisal edges occlude with or lie immediately below the angulum plateam of the upper incisors.immediately below the angulum plateam of the upper incisors.  Class II :Class II : The lower incisal edges lie part to the cingulumThe lower incisal edges lie part to the cingulum platean of the upper incisors.platean of the upper incisors.  Class III :Class III : the lower incisal edges lie anterior to the cingulumthe lower incisal edges lie anterior to the cingulum platean of the upper incisors. The overjet in reduced orplatean of the upper incisors. The overjet in reduced or reversed.reversed. www.indiandentalacademy.comwww.indiandentalacademy.com
  41. 41.  BALLARD’S CLASSIFICATIONBALLARD’S CLASSIFICATION  This classification is used to known the various skeletal relationship. It isThis classification is used to known the various skeletal relationship. It is used more accurately at the chairside.used more accurately at the chairside.  Accordingly different skeletal classes areAccordingly different skeletal classes are  SKELETAL CLASS I :SKELETAL CLASS I : The inclination of the teeth is normal and the dental baseThe inclination of the teeth is normal and the dental base relationship is also normal.relationship is also normal.  The projection of the axis of the lower incisors would pass through theThe projection of the axis of the lower incisors would pass through the crowns of the upper incisors.crowns of the upper incisors.  SKELETAL CLASS II :SKELETAL CLASS II :  The lower apical base is relatively too far back.The lower apical base is relatively too far back.  The lower incisors axis would pass palatal to the upper incisal crownThe lower incisors axis would pass palatal to the upper incisal crownSKELETALSKELETAL CLASS IIICLASS III  The lower apical base is placed relatively too far forward, (the projections ofThe lower apical base is placed relatively too far forward, (the projections of the lower incisors axis would pass labial to upper incisors crowns).the lower incisors axis would pass labial to upper incisors crowns).  .. www.indiandentalacademy.comwww.indiandentalacademy.com
  42. 42.  CANINE CLASSIFICATIONCANINE CLASSIFICATION  CLASS I -CLASS I - Mesial shape of upper canineMesial shape of upper canine  Coincides with the dental shape of lowerCoincides with the dental shape of lower caninecanine  CLASS II -CLASS II - Distal shape of upper canine coincidesDistal shape of upper canine coincides with the mesial shape fwith the mesial shape f  the lower canine.the lower canine.  CLASS III -CLASS III - Mesial shape of upper canine coincidesMesial shape of upper canine coincides with that of distalwith that of distal  shape of lower 1st premolarshape of lower 1st premolar www.indiandentalacademy.comwww.indiandentalacademy.com
  43. 43.  SALZMANN’S CLASSIFICATION :SALZMANN’S CLASSIFICATION :  Salzmann classified malocclusion its 4 group they areSalzmann classified malocclusion its 4 group they are  1.1. Dental :Dental : This group includes malposition and malocclusions of theThis group includes malposition and malocclusions of the teeth only Eg. (1) crowding (2) Spacing (3) Rotation.teeth only Eg. (1) crowding (2) Spacing (3) Rotation.  2.2. Dento alveolar group :Dento alveolar group : Here it involves malocclusion teeth and asHere it involves malocclusion teeth and as well as alveolar planes Eg. Abnormal overjet, overbite, cross bite.well as alveolar planes Eg. Abnormal overjet, overbite, cross bite.  3. Dental Arch malrelations :3. Dental Arch malrelations : this includes malreations of the dentalthis includes malreations of the dental arches in all three planes in sagittal plane: It includes mesiodistalarches in all three planes in sagittal plane: It includes mesiodistal realignment resulting in Class I, II and III.realignment resulting in Class I, II and III.  In transure plane :In transure plane : Resulting in anterior and posterior cross bites andResulting in anterior and posterior cross bites and also in vertical plane resulting in gen and rep bitealso in vertical plane resulting in gen and rep bite  4. Basal arch deficiency :4. Basal arch deficiency : it includesit includes  -- eg large basal arches resulting in diartemaseg large basal arches resulting in diartemas  - Constricted basal arches resulting in crowding- Constricted basal arches resulting in crowding www.indiandentalacademy.comwww.indiandentalacademy.com
  44. 44.  ACKERMAN – PROFIT SYSTEM OF CLASSIFICATION :ACKERMAN – PROFIT SYSTEM OF CLASSIFICATION :  In 1969 they proposed a diagrammatic classification of malocclusion. InIn 1969 they proposed a diagrammatic classification of malocclusion. In which characteristics and their inter relationships are assessed.which characteristics and their inter relationships are assessed.  This classification overcomes the major weaknesses of the Angle’s systemThis classification overcomes the major weaknesses of the Angle’s system of classification.of classification.  Salient features of this classification include :-Salient features of this classification include :-  Transverse as well as vertical discrepancies can be considered in addition toTransverse as well as vertical discrepancies can be considered in addition to anteroposterior malrelations.anteroposterior malrelations.  Crowding and arch asymmetry can be evaluatedCrowding and arch asymmetry can be evaluated  Incisors protrusion is taken into account.Incisors protrusion is taken into account.  This system of classification is based on Venn diagram that identifies fiveThis system of classification is based on Venn diagram that identifies five major characteristics to be considered.major characteristics to be considered. www.indiandentalacademy.comwww.indiandentalacademy.com
  45. 45.  STEP 1 (ALIGNMENT) :STEP 1 (ALIGNMENT) : They key word for this group is alignment.They key word for this group is alignment.  The 1st step involves assessment of the alignment and symmetry of theThe 1st step involves assessment of the alignment and symmetry of the dental arch.dental arch.  It is classified asIt is classified as  IdealIdeal  Crowded / spacedCrowded / spaced  STEP 2 (Profile) :STEP 2 (Profile) : The Key word for this group is profileThe Key word for this group is profile  It involves the considerations of the profile. The profile is described as convex /It involves the considerations of the profile. The profile is described as convex / straight / concave.straight / concave.  The facial divergence is also considered i.e. anterior divergence, posteriorThe facial divergence is also considered i.e. anterior divergence, posterior divergencedivergence  STEP 3 (TYPE) :STEP 3 (TYPE) : Key word for this group is typeKey word for this group is type  In this the transverse skeletal and dental relationship is evaluatedIn this the transverse skeletal and dental relationship is evaluated  Buccal and palatal cross bites if any are noted.Buccal and palatal cross bites if any are noted.  The cross bite is further sub classified as unilateral or bilateral.The cross bite is further sub classified as unilateral or bilateral.  In addition, differentiation is made between skeletal and dental cross bite.In addition, differentiation is made between skeletal and dental cross bite. www.indiandentalacademy.comwww.indiandentalacademy.com
  46. 46.  STEP 4 (Class )STEP 4 (Class ) Key word is classKey word is class  This involves the assessment of the sagittal relationship it is classifiedThis involves the assessment of the sagittal relationship it is classified as Angle’s class I, II / III malocclusions. Differentiations is made betweenas Angle’s class I, II / III malocclusions. Differentiations is made between skeletal and dental malocclusions.skeletal and dental malocclusions.  STEP 5 (Bite depth) : Key word for this group is bite depthSTEP 5 (Bite depth) : Key word for this group is bite depth  Malocclusion in the vertical plane are noted. They are described asMalocclusion in the vertical plane are noted. They are described as anterior or posterior open bites, anterior deep bite or Posterior collapsedanterior or posterior open bites, anterior deep bite or Posterior collapsed bite. Mention is made whether the malocclusions is skeletal or dental.bite. Mention is made whether the malocclusions is skeletal or dental.  The complexity of the orthodontic problem increases with the groupThe complexity of the orthodontic problem increases with the group number. Thus a group malocclusion is most complex in that there is annumber. Thus a group malocclusion is most complex in that there is an alignment problem, Problem is profile and Problem in the lateral, verticalalignment problem, Problem is profile and Problem in the lateral, vertical and antero posterior dimension as well.and antero posterior dimension as well. www.indiandentalacademy.comwww.indiandentalacademy.com
  47. 47.  ANGLE CLASSIFICATION REVISITEDANGLE CLASSIFICATION REVISITED  (A MODIFIED ANGLE CLASSIFICATION BY- KATZ)(A MODIFIED ANGLE CLASSIFICATION BY- KATZ)  A premolar derived classificationsA premolar derived classifications  After considering the advantages and disadvantages of theAfter considering the advantages and disadvantages of the angle’s classificationangle’s classification  Katz introduced a premolar derived classificationKatz introduced a premolar derived classification  He used premolars to evaluate ideal buccal occlusionHe used premolars to evaluate ideal buccal occlusion because.because.  Premolars usually prevent a sharply defined cusp tip, which isPremolars usually prevent a sharply defined cusp tip, which is centered on the central axis of the premolar crown.centered on the central axis of the premolar crown.  It fits precisely into the opposing embrasures.It fits precisely into the opposing embrasures.  The cuspal inclines are steeper and deeper than molar cuspsThe cuspal inclines are steeper and deeper than molar cusps (which makes a more positive fit.)(which makes a more positive fit.) www.indiandentalacademy.comwww.indiandentalacademy.com
  48. 48.  Class I (Class I (In modified Angle classification is defined as)In modified Angle classification is defined as)  The most anterior upper premolarThe most anterior upper premolar  Fits exactly into the embrasures created by the distal contactFits exactly into the embrasures created by the distal contact of the most anterior lower premolar.of the most anterior lower premolar.  This definition appliesThis definition applies  Whether a full complement of premolars are presentWhether a full complement of premolars are present  Whether one upper premolar opposes two lower premolarWhether one upper premolar opposes two lower premolar  Whether two upper premolars opposes one lower premolar (or)Whether two upper premolars opposes one lower premolar (or)  Whether only one premolar is present in each quadrantIn caseWhether only one premolar is present in each quadrantIn case  if there are no premolars exciting in the quadrant. Then the central axisif there are no premolars exciting in the quadrant. Then the central axis of the upper canine crown should be used as reference to the distalof the upper canine crown should be used as reference to the distal contact of the lower canine.contact of the lower canine. www.indiandentalacademy.comwww.indiandentalacademy.com
  49. 49.  Deciduous and mixed dentition classification.Deciduous and mixed dentition classification.  The deciduous and mixed dentium classificationThe deciduous and mixed dentium classification was not considered by angle.was not considered by angle.  But in the Katz modification.But in the Katz modification.  Class I :Class I : the center axis of the upper 1st deciduousthe center axis of the upper 1st deciduous molar should split the embrasure between both themolar should split the embrasure between both the lower deciduous molars.lower deciduous molars.  In case if the upper 1st deciduous molar isIn case if the upper 1st deciduous molar is prematurely last a line drawn through the center axisprematurely last a line drawn through the center axis of the edentulous space should bisect the embrasureof the edentulous space should bisect the embrasure between the two lower deciduous molars.between the two lower deciduous molars. www.indiandentalacademy.comwww.indiandentalacademy.com
  50. 50.  PSEUDO CLASS IPSEUDO CLASS I  Jan De Baets (JCO 1995 FEB)Jan De Baets (JCO 1995 FEB)  He introduced a new class I – The pseudo class I.He introduced a new class I – The pseudo class I. It is a skeletal class I in which the more teeth areIt is a skeletal class I in which the more teeth are located too mesially in relation to the mandible teethlocated too mesially in relation to the mandible teeth but a class I interdegilation has been obtained in thebut a class I interdegilation has been obtained in the buccal segment through mandibular anteriorbuccal segment through mandibular anterior crowding. Rotation of the maxillary 1st molars alsocrowding. Rotation of the maxillary 1st molars also play in the establishment of Angle class I molarplay in the establishment of Angle class I molar relation.relation.  www.indiandentalacademy.comwww.indiandentalacademy.com
  51. 51. www.indiandentalacademy.comwww.indiandentalacademy.com Thank you For more details please visit www.indiandentalacademy.com

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