1. DISORDERS OF DEVELOPMENT OF TEETH
By Dr.Shahzadi Tayyaba Hashmi
DNT 243

2. DEFECTS OF STRUCTURE OF TEETH
Enamel defects (Amelogenesis Imperfecta)
Dentine defects (Dentinogenesis Imperfecta)

3. Enamel Defects
Based on inheritance (autosomal dominant, recessive or X- linked)
Enamel hypoplasia, enamel hypomineralization, enamel hypomaturation
Based on appearance ( smooth, rough, pitted)
AMELOGENESIS IMPERFECTA

4. Hypoplastic Amelogenesis Imperfecta
Inadequate formation of enamel matrix
Enamel is randomly pitted, grooved or very thin
Hard and translucent.
Teeth are not susceptible to caries unless the enamel is easily damaged

5. 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

6. Hypomaturation Amelogenesis Imperfecta
Defect in the maturation of enamel crystals
Normal shape
Mottled appearance
White, yellow or brown
Enamel is soft
Vulnerable to attrition
(loss of tooth structure because of mechanical action of mastication)

7. Hypocalcified Amelogenesis Imperfecta
Chalky white appearance of teeth
Hypocalcified Amelogenesis Imperfecta
Pitted Enamel

8. Dentine Defects Dentinogenesis Imperfecta Dentine dysplasia
Regional Odontodysplasia (Ghost teeth)
DENTINOGENESIS IMPERFECTA

9. Dentinogenesis Imperfecta
Blue/brown discoloration of enamel
Bulbous crowns with cervical constrictions
Enamel defects (enamel is loosely attached and tend to chip away from the dentine easily.
Generally obliterated pulp chambers and canals
Periapical pathology
very difficult to treat
Teeth become rapidly worn down to gingiva in severe cases.
DENTINOGENESIS IMPERFECTA
(bulbous crowns)

10. RADIOGRAPHIC APPEARANCE OF DENTINOGENESIS IMPERFECTA
BLUE DISCOLORATION OF
ENAMEL
Bulbous crown
Absent pulp chambers
RADIOGRAPHIC APPEARANCE OF DENTINOGENESIS IMPERFECTA

11. Dentin Dysplasia Short 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

12. Regional Odontodysplasia ( ghost teeth)
Severe abnormalities of enamel , dentine and pulp
Recognized 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 enamel
Teeth appear crumbled (abnormal radiolucency) , ghost teeth

13. Disorders of eruption Delayed eruption Premature eruption
Impacted teeth

14. Premature Eruption
Erupted deciduous teeth present at birth are known as natal teeth
Deciduous teeth that erupts during first 30 days of life, termed as neonatal teeth
Premature 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

15. Natal Teeth

16. Delayed Eruption
Delayed eruption refers to the first appearance of deciduous teeth relative to the normal age range
Usually 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

17. Examples of gingival fibromatosis
(Teeth are buried inside the gingiva)

18. Impacted Teeth
DEFINITION :
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 Crowding
Supernumerary teeth
Odontogenic cysts
Odontogenic tumours
Most common impacted teeth are:
Maxillary and mandibular third molars
Maxillary cuspids

19. Types of Impaction
Impacted third molars have been classified according to their orientation within dental arch
Mesioangular impactions (most common type)
Distoangular impactions
Horizontal impactions
Vertical impactions

21. 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

22. Thank you