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