DEFECTS OF STRUCTURE OF TEETH

1. DEFECTS OF STRUCTURE 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 • Chipping of soft enamel of the incisal edge of upper incisors

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

7. 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 • Periapical pathology • very difficult to treat • Teeth become rapidly worn down to gingiva in severe cases DENTINOGENESIS IMPERFECTA (bulbous crowns)

10. 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. Disorders of eruption • Delayed eruption • Premature eruption • Impacted teeth

13. Premature Eruption • Erupted deciduous teeth present at birth are known as natalteeth • 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

14. Natal Teeth

15. Delayed Eruption • Delayed 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)

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

17. 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

18. 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

20. 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

21. Thank you