By Dr.Shahzadi Tayyaba Hashmi
DISORDERS OF DEVELOPMENT OF TEETH
DNT 243
DEFECTS OF STRUCTURE OF TEETH
Enamel defects (Amelogenesis Imperfecta)
Dentine defects (Dentinogenesis Imperfecta)
Enamel Defects
1. Based on inheritance (autosomal dominant, recessive or X-linked)
2. Enamel hypoplasia, enamel hypomineralization, enamel hypomaturation
3. Based on appearance ( smooth, rough, pitted)
AMELOGENESIS IMPERFECTA
Hypoplastic Amelogenesis Imperfecta
Inadequate formation of enamel matrixEnamel is randomly pitted, grooved or
very thinHard and translucent.Teeth are not susceptible to caries
unless the enamel is easily damaged
Hypocalcified Amelogenesis Imperfecta
Enamel matrix is formed in normal quantity but poorly calcified
During eruption , enamel is in normal thickness, but weak and opaque/chalky white appearance
Teeth tend to become stained and rapidly worn away
Chipping of soft enamel of the incisal edge of upper incisors
Hypomaturation Amelogenesis Imperfecta
Defect in the maturation of enamel crystals Normal shapeMottled appearanceWhite, yellow or brownEnamel is softVulnerable to attrition (loss of tooth structure because of mechanical
action of mastication)
Chalky white appearance of teeth
Hypocalcified Amelogenesis Imperfecta
Pitted Enamel
Dentine DefectsDentinogenesis ImperfectaDentine dysplasiaRegional Odontodysplasia (Ghost teeth)
DENTINOGENESIS IMPERFECTA
Dentinogenesis ImperfectaBlue/brown discoloration of enamelBulbous crowns with cervical constrictionsEnamel defects (enamel is loosely attached
and tend to chip away from the dentine easily.
Generally obliterated pulp chambers and canals
Periapical pathologyvery difficult to treatTeeth become rapidly worn down to gingiva
in severe cases.DENTINOGENESIS IMPERFECTA(bulbous crowns)
BLUE DISCOLORATION OF ENAMEL
RADIOGRAPHIC APPEARANCE OF DENTINOGENESIS IMPERFECTA
Bulbous crownAbsent pulp chambers
Dentin DysplasiaShort and conical roots (rootless teeth)Pulp chambers are obliterated by
multiple nodules of poorly organized dentine
Affected teeth may exhibit increased mobility and may exfoliate prematurely
Dentin dysplasia
Regional Odontodysplasia ( ghost teeth)Severe abnormalities of enamel , dentine and
pulpRecognized at the age of (2-4 yrs) during
eruption of deciduous teeth or (7-11 yrs) , during eruption of permanent teeth.
Maxillary teeth (commonly affected)Abnormal teeth fails to erupt, if they erupt ,
they show yellow deformed crowns with a rough surface
Affected tooth have very thin enamelTeeth appear crumbled (abnormal
radiolucency) , ghost teeth
Disorders of eruptionDelayed eruptionPremature eruptionImpacted teeth
Premature EruptionErupted deciduous teeth present at birth are
known as natal teethDeciduous teeth that erupts during first 30
days of life, termed as neonatal teethPremature eruption involves only one or two
teeth, most commonly the deciduous mandibular central incisors
Premature eruption of permanent teeth occurs because of premature loss of preceding deciduous teeth
In this case entire permanent dentition erupts prematurely
Natal Teeth
Delayed EruptionDelayed eruption refers to the first appearance of
deciduous teeth relative to the normal age rangeUsually associated with certain systemic
conditions like rickets, cleidocranial dysplasia and cretinism
Local factors such as gingival fibromatosis ( in which eruption may fail because the teeth are buried in the excessive fibrous gingival tissues and only their tips show in the mouth (pseuodoanodontia)
Delayed eruption of Permanent teeth may result from same local causes and systemic conditions that give rise to delayed eruption of deciduous teeth
Examples of gingival fibromatosis(Teeth are buried inside the gingiva)
Impacted TeethDEFINITION :Teeth that fail to erupt because of some physical barrier
are termed as impacted teeth
Examples of physical barriers that result in tooth impaction are as follows:
Dental CrowdingSupernumerary teethOdontogenic cystsOdontogenic tumoursMost common impacted teeth are:Maxillary and mandibular third molarsMaxillary cuspids
Types of Impaction Impacted third molars have been classified
according to their orientation within dental arch
1) Mesioangular impactions (most common type)
2) Distoangular impactions3) Horizontal impactions4) Vertical impactions
Essential referencesOral Pathology for the Dental Hygienist (5th
Edition) By Olga A. C. Ibsen, RDH, MS and Joan
Contemporary for oral and maxillofacial pathology by J.Phillip Sapp, Lewis Roy Eversole
Thank you
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