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

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

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

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

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 shape Mottled appearance White, yellow or brown Enamel is soft Vulnerable to attrition (loss of tooth structure because of mechanical action of mastication)

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

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

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)

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

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

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

Disorders of eruption Delayed eruption Premature eruption Impacted teeth

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

Natal Teeth

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

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

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

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

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