Developmental disturbances in structure of teeth Amelogenesis imperfecta /endodontic courses

Amelogenesis imperfecta
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

OBJECTIVES
 At the end of the lecture student should describe--
– Various developmental disorders affecting the structure of teeth
– Classification of Amelogenesis Imperfecta & enamel hypoplasia
– Etiopathogenesis & Clinical manifestations

Developmental disturbances
in structure of teeth
Amelogenesis imperfecta
Environmental enamel hypoplasia
Dentinogenesis imperfecta
Dentin dysplasia

Amelogenesis Imperfecta:-
It encompasses a complicated group of conditions that
demonstrate developmental alterations in the structure of the
enamel in the absence of a systemic disorder.

Environmental alterations of the
structure of enamel
During amelogenesis an external stimuli can result in
abnormalities in the enamel

Amelogenesis Imperfecta:-
Development of enamel takes place in three stages:-
 Formative stage- deposition of organic matrix.
 Calcification stage- matrix mineralization.
 Maturation stage- crystal enlargement and
maturation.
Three types of amelogenesis imperfecta:-
I. Hypoplastic
II. Hypocalcified
III. Hypomaturation

Classification by Witkop(1989)
I. Hypoplastic:-
Pitted autosomal dominant
Local autosomal dominant
Local autosomal recessive
Smooth, autosomal dominant
Smooth, X-linked dominant
Rough autosomal dominant
Enamel agenesis, autosomal recessive

Hypoplastic Amelogenesis
Imperfecta generalised pitted
pattern
Imperfecta smooth pattern
Imperfecta rough pattern

Amelogenesis Imperfecta
II. Hypomaturation:-
Pigmented autosomal recessive
X-linked recessive
Snow-capped teeth, autosomal dominant
III. Hypocalcified:-
Autosomal dominant
Autosomal recessive

Hypomaturation Amelogenesis
Imperfecta
Hypomaturation
snow-capped pattern
Hypocalcified Amelogenesis Imperfectawww.indiandentalacademy.com

IV. Hypomaturation- hypoplastic with taurodontism
Hypomaturation- hypoplastic with taurodontism, autosomal
dominant
Hypoplastic- hypomaturation with taurodontism, autosomal
dominant
Hypomaturation-
hypoplastic
with taurodontism

Clinical Features:-
Hypoplastic:- enamel not formed to full thickness.
Hypocalcified:- soft enamel.
Hypomaturation:- enamel can be pierced by explorer and
chipped away.

Clinical Features:-
Variable clinical appearance
Range from normal appearing to
unsightly teeth.
Yellow to dark brown appearance.
Smooth or wrinkled
No contact points between teeth
with incisal & proximal wear.

Radiographic features
Absence or thinning of enamel
Radiographic opacity may become similar to dentin

Histopathology:-
Depends on type.
Defects in matrix formation to absence of matrix formation.
Defective mineral deposition.
Alteration in enamel rod and rod sheath structures.

Enamel Hypoplasia
Incomplete or defective formation of the organic enamel
matrix
Two types-
Hereditary type ( Amelogenesis Imperfecta)
 Affects both dentition
 Only enamel is affected
 Environmental
 Either dentition or only single tooth
 Both enamel and dentin

Environmental Enamel Hypoplasia
Different factors are :
 Nutritional deficiency
 Exanthematous diseases
 Congenital syphilis
 Hypocalcemia
 Birth injuries
 Local infection/ trauma
 Ingestion of chemicals
 Idiopathic

Nutritional deficiency &
Exanthematous fevers
Rickets during time of tooth
development
Deficiency of vit. A & vit. C
Exanthematous disease like measles,
chickenpox, scarlet fever

Clinically manifest as
 Horizontal rows of pits
 Diminished enamel
 Location of the defects correlates well with the
development stage of the affected teeth.

Most commonly involved teeth are –central & lateral incisors,
canines & first molars

 Maxillary and mandibular permanent incisor and 1st
molars.
 Hutchinson’s incisor
 Mulberry, Moons, Fournier’s molars

Hutchinson’s incisor
Permanent central incisor –
Screw driver shaped due to
convergence of mesial and
distal sides and notched incisal
edge due to absence of central
calcification centre.

Mulberry molars
Molars- enamel of
occlusal surface and
occlusal 1/3rd shows mass
of globules instead of
cusps.

Enamel hypoplasia due to
hypocalcemia
Tetany due to decreased level of
calcium in blood.
Due to vitamin D deficiency and
parathyroid deficiency.
Clinically manifest as pitting variety

SUMMARY
– Various developmental disorders affecting the structure of
teeth
– Classification of Amelogenesis Imperfecta & enamel
hypoplasia

– Etiopathogenesis & Clinical manifestations

Bibliography
Shafer’s text book of oral pathology 5th
& 6th
edition
Oral and maxillofacial pathology Neville, 2nd
edition
Color atlas of oral diseases Cawson, R. A.
8th
edition

Developmental disturbances in structure of teeth Amelogenesis imperfecta /endodontic courses

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