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Etiology of Etiology of malocclusion malocclusion by:- by:- Anshdeep singh Anshdeep singh

Etiology of Malocclusion

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Page 1: Etiology of Malocclusion

Etiology of malocclusionEtiology of malocclusion

by:- by:-

Anshdeep singh Anshdeep singh

c.r.r.ic.r.r.i

Page 2: Etiology of Malocclusion

IntroductionIntroduction

Malocclusion may be defined asMalocclusion may be defined as

a significant deviation from what is defined as a significant deviation from what is defined as normal or ideal occlusion (Andrews,1972)normal or ideal occlusion (Andrews,1972)

The term ‘normal occlusion' is arbitrary,The term ‘normal occlusion' is arbitrary,

but is generally accepted to be class I molar but is generally accepted to be class I molar relationship with good alignment of all teethrelationship with good alignment of all teeth

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ClassificationClassification

Graber’sGraber’sMoyer’sMoyer’sWhite & Gardiner’sWhite & Gardiner’sSalzmann’sSalzmann’s

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Moyer’sMoyer’s

HeredityHeredity Developmental defects of unknown originDevelopmental defects of unknown origin TraumaTrauma Physical agentsPhysical agents HabitsHabits DiseasesDiseases MalnutritionMalnutrition

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White & Gardiner’sWhite & Gardiner’s

Dental base abnormalitiesDental base abnormalities Pre-eruption abnormalitiesPre-eruption abnormalities Post-eruption abnormalitiesPost-eruption abnormalities

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Salzmann’sSalzmann’s

GENETIC ENVIRONMENTAL

DEVELOPMENTAL

CONGENITAL FUNCTIONAL

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Graber’sGraber’s

General FactorsGeneral Factors Local FactorsLocal Factors

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General FactorsGeneral Factors

HeredityHeredity Congenital DefectsCongenital Defects EnvironmentEnvironment Predisposing Metabolic Climate and DiseasePredisposing Metabolic Climate and Disease Dietary ProblemsDietary Problems Abnormal Pressure Habits and Functional Abnormal Pressure Habits and Functional

AberrationsAberrations PosturePosture Trauma and AccidentsTrauma and Accidents

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Local FactorsLocal Factors Anomalies of Number of teethAnomalies of Number of teeth Anomalies of Tooth SizeAnomalies of Tooth Size Anomalies of Tooth ShapeAnomalies of Tooth Shape Abnormal Labial Frenum; mucosal barriersAbnormal Labial Frenum; mucosal barriers Pre mature LossPre mature Loss Prolonged RetentionProlonged Retention Delayed eruption of Permanent TeethDelayed eruption of Permanent Teeth Abnormal Eruptive PathAbnormal Eruptive Path AnkylosisAnkylosis Dental CariesDental Caries Improper Dental RestorationsImproper Dental Restorations

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HeredityHeredity

Genetically homogenous population tend to Genetically homogenous population tend to have normal occlusion as the Melanesians of have normal occlusion as the Melanesians of the Philippine islands, in whom the the Philippine islands, in whom the malocclusion is almost non-existent.malocclusion is almost non-existent.

In heterogenous population , the incidence of In heterogenous population , the incidence of jaw discrepancies and occlusal disharmonies is jaw discrepancies and occlusal disharmonies is significantly greater.significantly greater.

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Primary sites affected by genetically Primary sites affected by genetically transferred dentofacial deformities transferred dentofacial deformities Neuromuscular systemNeuromuscular system DentitionDentition Bone & CartilageBone & Cartilage Soft Tissues (except muscles)Soft Tissues (except muscles)

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Lip deformitiesLip deformities

The lower lip plays more The lower lip plays more important role than the upper important role than the upper lip in function movements and lip in function movements and in governing the position of in governing the position of lower incisors in normal lower incisors in normal function during swallowing, function during swallowing, speech & smiling. speech & smiling. 

The inherited pattern of lips The inherited pattern of lips can result in malocclusion.can result in malocclusion.

Abnormalities in lip form and Abnormalities in lip form and lip line can cause lip line can cause malocclusion.malocclusion.

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Tongue deformitiesTongue deformities

Tongue SizeTongue Size: Macroglossia : Macroglossia MicroglossiaMicroglossia

Tongues PositionsTongues PositionsIn case of In case of

incompetent lips, tongue incompetent lips, tongue protrudes between the teeth to protrudes between the teeth to touch the lower lips. This allows touch the lower lips. This allows nasal breathing n prevents full nasal breathing n prevents full vertical development of incisors vertical development of incisors leading to open bite.leading to open bite.

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DentitionDentition

AbnormalitiesAbnormalities Size, shape, number of teethSize, shape, number of teeth Mineralization of teethMineralization of teeth Path of eruption in primary position of tooth Path of eruption in primary position of tooth

germgerm Sequence of eruptionSequence of eruption

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SizeSize Microdontia Microdontia

MacrodontiaMacrodontia

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ShapeShape

FusionFusionGeminationGemination

TwinningTwinning

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NumberNumber

HypodontiHypodontiaaMSX1 & PAX9 genes are found

to be involved in some families with non-syndromic autosomal dominant hypodontia .

HyperodontiaHyperodontia Supernumary teeth,most frequently seen in premaxillary region with male sex predilection, are also genetically determined

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MineralisationMineralisation

Inherited defects differ from exogenic induced Inherited defects differ from exogenic induced disturbancesdisturbances present in both deciduous & permanent teethpresent in both deciduous & permanent teeth localized in either enamel or dentinlocalized in either enamel or dentin arranged irregularly or as vertical ridges & grooves arranged irregularly or as vertical ridges & grooves

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Bones & CartilageBones & Cartilage Bone morphology or growth alter occlusal relation & Bone morphology or growth alter occlusal relation &

functioningfunctioning FactorsFactors

Bone size Bone size Shape of jaw basesShape of jaw bases Bone locationBone location Number of bones presentNumber of bones present

Inherited skeletal malocclusionsInherited skeletal malocclusions Class II, division 2Class II, division 2 Mandibular PrognathismMandibular Prognathism Bimaxillay protrusionBimaxillay protrusion Skeletal open bitesSkeletal open bites Mandibular retrognathismMandibular retrognathism

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Bone sizeBone size

MacrognathismMacrognathism MicrognathismMicrognathism

Hypolasia of jaws occurs with craniofacial Hypolasia of jaws occurs with craniofacial dysostosis, cleidocranial, dysostosis & crouzon’s dysostosis, cleidocranial, dysostosis & crouzon’s diseasesdiseases

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Bone LocationBone Location

PrognathismPrognathism Mandibular prognathism and Mandibular prognathism and

class II division 2 are attributed to class II division 2 are attributed to dominant inheritance.dominant inheritance.

Best known example of familial Best known example of familial mandibular prognathism is mandibular prognathism is referred to as the referred to as the Hapsburg jaw.Hapsburg jaw.

RetrognathismRetrognathism

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Soft TissuesSoft Tissues

Hemifacial Hemifacial microsomiamicrosomia

AnkyloglossiaAnkyloglossiaAnomalies of FrenumAnomalies of Frenum

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Genetic SyndromesGenetic Syndromes

Achondroplasia Achondroplasia Pierre Robin syndrome Pierre Robin syndrome Craniofacial dysostosisCraniofacial dysostosis Treacher Collins syndrome Treacher Collins syndrome Down’s syndrome Down’s syndrome Gardner’s syndrome Gardner’s syndrome Marfan syndromeMarfan syndrome Cleidocranial dysplasiaCleidocranial dysplasia

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Caused by developmental damage during fetal Caused by developmental damage during fetal period Cleft lip & Palateperiod Cleft lip & Palate Cerebral palsyCerebral palsy TorticollisTorticollis Congenital syphilisCongenital syphilis

Congenital DeformitiesCongenital Deformities

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Cleft lip & PalateCleft lip & Palate

Most frequent congenital Most frequent congenital deformitydeformity

Incidence 1:700 live birthsIncidence 1:700 live births Can be caused by the use of Can be caused by the use of

teratogens like , aspirin, dilantin, teratogens like , aspirin, dilantin, 6-mercaptopurine, valium and 6-mercaptopurine, valium and cigarette smoke. cigarette smoke.

In Unilateral cleft, teeth on the In Unilateral cleft, teeth on the affected site are in lingual cross affected site are in lingual cross bite bite

Teeth are frequently crowded in Teeth are frequently crowded in cleftcleft

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Cerebral palsyCerebral palsy

Paralysis or lack of muscular coordination Paralysis or lack of muscular coordination attributed to intracranial lesion attributed to intracranial lesion

Commonly result of birth injuryCommonly result of birth injury Lack of motor control causes abnormal Lack of motor control causes abnormal

function in mastication ,deglutition ,respiration function in mastication ,deglutition ,respiration & speech. Thus affects normal occlusion .& speech. Thus affects normal occlusion .

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Congenital syphilisCongenital syphilis

Peg shaped lateralsPeg shaped laterals Mulberry molarsMulberry molars Notched incisorsNotched incisors Enamel hypoplasiaEnamel hypoplasia Delayed eruptionDelayed eruption Narrow maxillary archNarrow maxillary arch

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Prenatal influencePrenatal influence

Uterine posture , fibroids of mother , amniotic Uterine posture , fibroids of mother , amniotic lesions lesions

German measles , maternal diet , metabolism , German measles , maternal diet , metabolism , drug like thalidomide induced deformitiesdrug like thalidomide induced deformities

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Forceps delivery can injure Forceps delivery can injure the TMJ the TMJ

Disabling accidents Disabling accidents produces malocclusionproduces malocclusion

Milwaukee braces wear Milwaukee braces wear produces malocclusionproduces malocclusion Maxillary incisors are tipped Maxillary incisors are tipped

labially labially Mandibular incisors fit into Mandibular incisors fit into

deep palatal groovesdeep palatal grooves

Postnatal influencePostnatal influence

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Predisposing metabolic climate & Predisposing metabolic climate & diseasedisease

Exanthematous fever Exanthematous fever disturbs disturbs developmental time developmental time table and often leave table and often leave permanent marks on permanent marks on surfaces of teeth. surfaces of teeth.

Endocrine disorders Endocrine disorders Infectious diseasesInfectious diseases

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Endocrine disordersEndocrine disorders

Prenatally , manifest as hypoplasia of teeth.Prenatally , manifest as hypoplasia of teeth. Postnatally , retard or hasten , but do not Postnatally , retard or hasten , but do not

disrupt the direction of facial growth. May disrupt the direction of facial growth. May affect the rate of ossification of bone , eruption affect the rate of ossification of bone , eruption of teeth & resorption of primary teeth.of teeth & resorption of primary teeth.

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Infectious diseasesInfectious diseases

Nasopharyngeal diseases & impeded nasal breathing. Nasopharyngeal diseases & impeded nasal breathing. Enlarged adenoids causesEnlarged adenoids causes

Increased anterior facial height Increased anterior facial height narrow and high palatenarrow and high palate Retroclined incisors Retroclined incisors Increased lower facial height Increased lower facial height Open bite & cross bite Open bite & cross bite

Gingival and periodontal diseasesGingival and periodontal diseases Causes loss of teeth Causes loss of teeth Ankylosis of teethAnkylosis of teeth

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Nutritional deficiencyNutritional deficiency

Malocclusion caused by disturbed Malocclusion caused by disturbed developmental time table in :developmental time table in :

- Rickets - Rickets – Vit. D deficiency– Vit. D deficiency

- Scurvy – - Scurvy – Vit. C deficiencyVit. C deficiency

- Beri beri – Beri beri – Vit. B1 deficiencyVit. B1 deficiency Malocclusion is caused due to Malocclusion is caused due to

Premature loss of teethPremature loss of teeth Prolonged retention Prolonged retention Poor tissue health Poor tissue health Abnormal eruptive pathsAbnormal eruptive paths

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Abnormal pressure habitsAbnormal pressure habits

Habits are learned patterns of muscle Habits are learned patterns of muscle contraction.contraction. Thumb & digit sucking Thumb & digit sucking Tongue thrusting Tongue thrusting Lip biting & sucking Lip biting & sucking Nail biting Nail biting

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PosturePosture

Stoop shouldered child with head hung so that Stoop shouldered child with head hung so that the chin rests on chest may have mandibular the chin rests on chest may have mandibular retrusion.retrusion.

Child resting his head on his hands or sleeping Child resting his head on his hands or sleeping on his arms , fists can have malocclusionon his arms , fists can have malocclusion

Poor posture accentuates an existent Poor posture accentuates an existent malocclusion malocclusion

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LOCAL FACTORSLOCAL FACTORS 1.     Anomalies of number 1.     Anomalies of number

a)     Supernumerary teeth. a)     Supernumerary teeth. b)    Missing teeth (congenital absence or loss b)    Missing teeth (congenital absence or loss due to trauma, caries, etc.) due to trauma, caries, etc.) 2.     Anomalies of tooth size. 2.     Anomalies of tooth size. 3.     Anomalies of tooth shape. 3.     Anomalies of tooth shape. 4.     Abnormal labial frenum. 4.     Abnormal labial frenum.

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5.     Premature loss5.     Premature loss

6.     Prolonged retention6.     Prolonged retention

7.     Delayed eruption of permanent teeth7.     Delayed eruption of permanent teeth

8.     Abnormal eruptive path8.     Abnormal eruptive path

9.     Ankylosis9.     Ankylosis

10.   Dental caries10.   Dental caries

11. Improper dental restorations11. Improper dental restorations

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1) Anomalies of number A) Supernumerary teeth: Supernumerary teeth is a teeth, which is various in size , shape and location when compared to the

normal teeth. B) Supplemental teeth : Supplemental teeth is a teeth ,which is closely

resembles the particular group of teeth. This is most commonly seen in premolar region and

lateral incisor region.

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Supernumerary teeth result from disturbances Supernumerary teeth result from disturbances during the initiation and proliferation stages of during the initiation and proliferation stages of dental development.dental development.

Supernumerary teeth occur most commonly in Supernumerary teeth occur most commonly in the maxilla..the maxilla..

The most commonly seen The most commonly seen supernumerarysupernumerary teeth is mesiodens.teeth is mesiodens. Mesiodens is a small tooth with a cone Mesiodens is a small tooth with a cone

shaped crown and short root.shaped crown and short root.

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Supernumerary teeth

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It is seen between the two maxillary central incisors.

The presence of teeth obviously has great potential to disturb normal occlusal development.

The frequency of other supernumerary teeth are paramolars and distomolars.

Multiple supernumerary teeth are seen in cleidocranial dysplasia.

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B) Congenitally Missing Teeth

Congenital absence of teeth results from disturbances during the intial stages of tooth formation . 

Anodontia – Total absence of teeth 

Oligodontia - Absence of many but not all the teeth.  Oligodontia showed a tendency for delayed

tooth formation

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Ectodermal dysplasiaEctodermal dysplasia

Ectodermal dysplasia is characterized by Ectodermal dysplasia is characterized by soft , smooth , thin and dry skin with partial soft , smooth , thin and dry skin with partial or complete absence of sweat glands.or complete absence of sweat glands.

The sebaceous glands and hair follicles are The sebaceous glands and hair follicles are absence.absence.

The bridge of the nose are depressed.The bridge of the nose are depressed. This also manifested with anodontia orThis also manifested with anodontia or Oligodontia.Oligodontia.

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Frequency of absence(Missing)

Maxillary and Mandibular third molars Maxillary lateral incisors Mandibular second premolar Mandibular incisors Maxillary second premolar

Congenitally missing teeth can lead to spacing between teeth and aberrant swallowing pattern.

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Congenitally Missing Lateral Congenitally Missing Lateral IncisorsIncisors

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2)Anomalies of Tooth Size : 

A tooth size is determined by heredity .

Anomalies of Tooth Size

Microdontia Macrodontia

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True generalized microdontia is usually associated with pituitary dwarfism.

True generalized macrodontia is usually associated with pituitary gigantism.

The most commonly localized microdontia involves the maxillary lateral incisors (peglaterals).

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Macrodontia

Microdontia

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3)Anomalies of Tooth Shape : 

Intimately related to tooth size is tooth shape.

Abnormal shaped teeth predispose to malocclusion.

  Presence of maxillary-‘Peg lateral’ incisors spacing will often occur in the maxillary anterior segment.

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Abnormally large cingulum on the maxillary incisor (Talons cusp) or heavy marginal ridge can force the teeth labially and prevent the establishment of a normal overbite-overjet relationship.

Mandibular second premolar also shows great variation in shape & size. It may have an extra lingual cusp , which usually serve to increase the mesiodistal dimension of the tooth.

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Anomalies of shape can also occur as a result of

amelogenesis imperfecta, hypoplasia, gemination, dens in dente, odontomas , fusion and congenital syphilitic aberration such as

Hutchinson‘s incisors and mulberry molars.

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4) Abnormal Labial Frenum

Abnormalities of the maxillary labial frenum are associated with a midline diastema .

At birth frenum is attached to the alveolar ridge with fibers running into the incisive papilla. The teeth erupts and as alveolar bone is deposited, the frenum attachment migrates superiorly with the alveolar ridge

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Abnormal Labial Frenum

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Fibers may persist between the maxillary central incisors and in the ‘V’ shaped intermaxillary suture , attaching to the outer layer of the periosteum and connective tissue of the suture.

Faust in Weber ,noted that diastema may be due to other factors, the possible causative factors : Microdontia, Macrognathia,Super numerary teeth,Peg laterals,Missing lateral incisors ,Habits as thumb sucking, tongue thrusting & midline pathologies

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5)Premature loss of Deciduous teeth

Deciduous teeth are the space savers for the permanent teeth.

They also maintaining the opposing teeth at the proper occlusal level.

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Deciduous cuspids are frequently shed pre-Deciduous cuspids are frequently shed pre-maturely and nature provide more space to align maturely and nature provide more space to align the permanent incisor teeth that have already the permanent incisor teeth that have already erupted. erupted.

Pre mature removal of posterior deciduous Pre mature removal of posterior deciduous teeth because of caries Malocclusion unless teeth because of caries Malocclusion unless space maintainers are placed.space maintainers are placed.

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6)Prolonged retention of deciduous teeth

Whatever the reason for the prolonged retention of deciduous teeth, they have a significant impact on the dentition. 

Whichever deciduous teeth may be retained beyond the usual eruption age of their permanent successor is capable of causing buccal / labial or Palatal / Lingual deflection. 

Impacted in the maxillary arch might lead to the permanent tooth erupting is a cross bite,which might be difficult to treat at a later stage

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Impacted Permanent teeth are more difficult to correct orthodontically, by surgical exposure most commonly impacted tooth is the maxillary canine(3rd molars not in consideration) the reason-

  It’s the last anterior tooth to erupt.

Space occupied by the deciduous canine is lesser than the mesiodistal width of the permanent canines.

It has longer path of eruption

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7 )Delayed eruption of permanent teeth

Reasons: 1.Early loss of adjacent primary teeth with a

consequential flaring or spacing between erupted teeth may lead to decreased space availability for eruption of the succedaneous teeth.

2. Early loss of primary tooth leading to mucosal thickening over the succedaneous tooth .

3. Early loss of the primary tooth might cause excessive bone deposition over the succedaneous tooth.

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4. Due to hereditary in certain children teeth erupt much later than established norms.

5.Presence of supernumerary tooth can block the erupting permanent tooth.

6. Presence of odontomas or other cysts and tumors might prevent the permanent tooth from erupting. 

7. Presence of deciduous root fragment that are not resorbed can block these erupting tooth or may deflect it preventing its eruption in an ideal location.

8. Presence of ankylosed deciduous teeth,these might not get resorbed causing a delay in the eruption of the permanent tooth

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9. The succedaneous tooth might be congenitally missing delaying the loss of the primary tooth.

10. In certain endocrine disorders the eruption of permanent teeth might be delayed.

Eg: hypothyroidism.

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8)Abnormal Eruptive path

1.Tooth bud facing and/or placed or displaced from its ideal location.

2.Presence of a supernumerary tooth may divert a tooth from its eruptive path.

3. Presence of odontomas or a cyst tumour may divert it if not altogether prevent its eruption.

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4. Un resorbed or retained deciduous teeth might force a tooth to erupt along a path of least resistance rather than in place of the deciduous tooth.

5. Retained root fragments may deflect an erupting permanent tooth.

6.Arch length deficiencies or excess of tooth material may cause one or more teeth to deviate from their eruptive path.

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Ectopic Eruption

Malposition of a permanent tooth bud can lead to eruption in wrong place.This condition is called ectopic eruption.

Most likely to occur in the eruption of maxillary first molars.

Ecotopic eruption may generally be considered a manifestation of arch length deficiency.

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Ectopic eruptionEctopic eruption

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9)Ankylosis

Ankylosis is the condition which involves the union of the root or part of a root directly to the bone, without the intervening periodontal membrane.

Ankylosis or partial ankylosis is encountered relatively frequently during the 6 to 12 year age period.

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Ankylosis of teeth is more commonly associated with certain infections, endocrine disorders and congenital disorders.

Ex : Cleidocranial dysostosis , but there are rare occurrences.

Ankylosis may be due to past history of trauma.

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10)Dental caries

Dental caries which leads to the premature loss of a deciduous or permanent tooth subsequent drifting of contiguous teeth ,abnormal axial inclination,over eruption and bone loss.

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11)Improper dental restorations

Due to improper dental restoration under contoured proximal restoration can lead to a significant decrease in the arch length especially in the deciduous molars.

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