By Dr.Shahzadi Tayyaba Hashmi

DEFECTS OF STRUCTURE 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 translucentTeeth 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

Chipping of soft enamel of the incisal edge of upper incisors

Hypomaturation Amelogenesis Imperfecta

Defect in the maturation of enamel crystalsMottled 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 Imperfecta

Blue/brown discoloration of enamelBulbous crowns with cervical constrictionsPeriapical 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 dentineAffected teeth may exhibit increased

mobility and may exfoliate prematurely

Dentin dysplasia

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 range

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)

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 references

Oral 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