Amelogenesis imperfecta, hypoplastic type - Dr Sanjana Ravindra

GOODMORNIN

G

Dr Sanjana Ravindra

Post graduate Student

Oral Medicine and

Radiology

Amelogenesis Imperfecta, Hypoplastic Type

Associated with Some Dental Abnormalities:

A Case Report

Canger EM, Celenk P, Yenísey M, Odyakmaz SZ. Braz Dent J (2010) 21(2): 170-174.

JOURNAL CLUB: 3

Introduction

DEVELOPMENTAL

DISTURBANCES an abnormality where the

pathology starts in the

embryonic stage of human

life , before the formation

of the dentition

Orban’s Oral Histology and Embryology, 12th edition

Introduction

DEVELOPMENTAL TOOTH

ANOMALIES

SIZE

• Microdontia

• Macrodontia

NUMBER

• Anodontia

• Supernumerary

teeth

• Pre-deciduous

dentition

STRUCTURE

• AMELOGENESIS

IMPERFECTA

• Dentinogenesis

imperfecta

• Dentin dysplasia

• Regional

odontodysplasia

• Dentin

hypocalcification

SHAPE • Gemination

• Twinning

• Fusion

• Concrescence

• Talon cusp

• Dilaceration

• Dens in dente

• Dens evaginatus

• Enamel pearl

• Globodontia

• Mulberry molar

• Moon’s molar

• Hutchinson incisor

• Carabelli cusp

• Shovel shaped

incisor

encompasses a

complicated

group of conditions

that demonstrate

developmental

alterations in the

structure of the

enamel in the

absence

of a systemic

disorder.

AMELOGENESIS

IMPERFECTA

AMELOGENES

IS ?IMPERFECT

A

Hereditary

enamel

dysplasia

Hereditary

brown enamel

Hereditary

brown

opalescent

teeth

Shafer’s textbook of Oral Pathology. 6th ed. Elsevier;

2009

www.merriam-webster.comIntroduction

Case report

Canger EM, Celenk P, Yenísey M, Odyakmaz SZ. Amelogenesis Imperfecta, Hypoplastic

Type, Associated with Some Dental Abnormalities: A Case Report: Braz Dent J (2010)

21(2): 170-174.

Case reportB

IOD

ATA A 26-year-old

female

CH

IEF

CO

MP

LA

INT discolored teeth

ME

DIC

AL H

IST

OR

Y noncontributory.

FA

MIL

Y

HIS

TO

RY

None had

similar

problem

GINGIVA

Hyperemic and edematous gingiva.

No gingival enlargement

ORAL HYGIENE

Poor

Clinical crown length

Adequate

Case report

17 16 55 14 13 52 11 21 22 24 25 26

46 85 44 83 42 41 31 32 73 44 75 36

Clinically short

Yellow-brown coloured

Loss of contact

• CROWNS

Decreased –vertical dimension

Case report

Panoramic

view

Intraoral

periapical

radiographs

Periodontal therapy

Oral hygiene instructions, scaling, and root planning.

Prosthodontic rehabilitation

Full-mouth metal reinforced porcelain

fixed bridge restoration

Advised and motivated for maintenance of proper oral hygiene & Repeated follow ups

2 WEEKS -

NORMAL

GINGIVA

VERTICAL

DIMENSION

NORMAL

ESTHETIC OR

FUNCTIONAL

PROBLEMS

Case report

DISCUSSION

Introduction

Tooth enamel consists mainly of inorganic material (96%) and oraganic

substance and water(4%)

Physical properties and physiological function of enamel – directly

related to composition, orientation, disposition and morphology of

mineral components within tissue

During organogenesis, enamel transitions from soft to pliable tissue to

its final form- is devoid of protein

Final composition is reflection of unique molecular and cellular

activities that take place during its genesis

Deviation from this pattern lead – AMELOGENESIS IMPERFECTA

SYNONYMS

Hereditary enamel dysplasia

Hereditary brown enamel

Hereditary brown opalescent teeth

“AI encompasses a complicated group of conditions that demonstrate

developmental alterations in structure of the enamel in the absence of

a systemic disorder”

“AI represents a group of conditions, genomic in origin, which affect the

structure and clinical appearance of the enamel of all or nearly all the

teeth in a more or less equal manner, and which may be associated

with morphologic or biochemical changes elsewhere in the body”

Orphanet Journal of Rare Diseases 2007,

2:17

Definition

Historical background

Spokes in 1890,

described "brown

teeth" with a familial

history.

In 1907 Turner described

some cases of

hereditary hypoplasia of

teeth in five generations

of same family

Weinmann & associates in 1945 –

introduced term “AMELOGENESIS

IMPERFECTA” – it is an ectodermal

disturbance, mesodermal components

are normal

ETIOLOGY

Dental enamel is a highly mineralised tissue

Derived through the synthesis and secretion of proteins

Formation of this highly organised and unusual structure is controlled in

ameloblasts through interaction of a number of organic matrix molecules

Development of normal enamel occurs in three stages

1. Formative stage – deposition of organic matrix – Hypoplastic AI

2. Calcification stage – matrix is mineralized –Hypocalcified AI

3. Maturation stage – crystallites enlarge and mature –

Hypomaturative AI

ETIOLOGY

Genes and phenotypes

Proteins/ enzymes

forming enamel

Type of AI Inheritance

1 Amelogenin Diffuse smooth

hypoplastic &

hypomaturation

X linked

2 Ameloblastin Hypocalcified AD

3 Enamelin Hypoplastic AD, AR

4 Tuftelin hypoplastic AD,AR

5 Kallikrein Hypomaturation AR

6 Matrix metalloproteinase Pigmented

hypomaturation

AR

Modes of Mendelian Inheritance Associated with AI

https://www.google.co.in/search?q+phenotype

CLASSIFICATION

Sekar B, Dominic Augustine, Murali S.

Amelogenesis Imperfecta - A Case Report with

Genetic Transmission. IJDA, 2(4), October-

December, 2010 395.

Hypoplastic

Hypocalcified

By Weinnman et al (1945)

BASED ON CLINICAL, MICRORADIOGRAPHIC

AND HISTOPATHOLOGICAL FINDINGS BY

Darling (1956)

Hypoplastic

Group 1 – gen pitting

Group 2- vertical grooves

Group 3- gen hypoplasia

Hypocalcified

Type 4A- chalky, yellow, brown enamel

Type 4B- marked enamel discolouration 7 softness with post

eruptive loss of enamel

Type 5- gen/ localized discolouration and chipping of enamel

By Witkop

(1957)

Hypoplastic

Hypocalcification

Hypomaturation Pigmented

hypomaturation

Local hypoplasia

By Schulze

(1970)

Type 1 hypoplastic Specific features , inheritance

1A Hypoplastic, pitted AD

1B Hypoplastic, local AD

1C Hypoplastic, local AR

1D Hypoplastic, smooth AD

1E Hypoplastic, smooth x-linked D

1F Hypoplastic, rough AD

Typw 2 hypomaturation

2A hypomaturation

2B hypomaturation

2C Snow capped teeth, x linked

2D AD

Type 3 hypocalcification

3A AD

3B AR

Type 4 Hypomaturation- hypoplastic with taurodontismType 4A Hypomaturation- hypoplastic with

taurodontism AD

Type 4B Hypoplastic- hypomaturation with taurodontism AD

Neville BW, Douglass DD, Allen CM, Bouquot JE. Abnormalities of teeth. In: Oral and Maxillofacial Pathology. 2nd ed.. Pennsylvania:Elsevier;2004. 89

Prevalence range from 1 in 718 to 1 in 14,000, depending on the

population studied.

Hypoplastic AI represents 60 – 73% of all cases,

Hypomaturation AI represents 20 – 40%, and

Hypocalcification AI represents 7%

Prevalence

Clinical features

Hypoplastic type

Gen. pitted

Localized pitted

Diffuse smooth

Diffuse rough

ADLocalized pitted

Enamel Agenesis

AR

Males

Females

X-linked

Hypoplastic type – autosomal dominant

GENERALIZED PITTED

• Thin enamel

• Open contact

• Pinpoint to pinhead pits

• Newly erupted teeth: hard with normal yellow-white colour

• Staining of teeth-exposure to oral environment- black appearance

LOCALIZED PITTED

• Linear depression/ large area of hypoplasia

• Prominent on buccal surface

DIFFUSE SMOOTH

• Thin, glossy with smooth surface

• ¼ to 1/8 of normal thickness

• Yellow color –opaque to translucent brown

• Delayed eruption with alveolar resorption

DIFFUSE ROUGH

Hard with rough granular surface

White to yellowish white

Thicker enamel at cervical areas

https://www.google.co.in/search?q=amelogenesis+hypoplastic

Localized pitted

Severe form of AD

Enamel agenesis

Yellow colour like normal dentition

Surface is rough & granular-ground glass

Complete lack of enamel formation

Multiple missing teeth


Hypoplastic type – autosomal recessive

Males

– Thin, hard, glossy

– Like crown preparations, open bite

– Opaque white to brown

Females

– Alternating vertical bands of normal and

abnormal enamel


Hypoplastic type – x-linked dominant

Hypoplastic amelogenesis

imperfecta, gen pitted pattern .

Note the numerous pinpoint pits

scattered across the surface of

the teeth. The enamel between

the pits is of

normal thickness. hardness. and

coloration.

Hypoplastic amelogenesis

imperfecta, autosomal dominant

smooth pattern.

Small. yellowish teeth exhibiting

hard, glossy enamel with open

contact Points and anterior

open bite.

Neville BW, Douglass DD, Allen CM, Bouquot JE. Abnormalities of teeth. In: Oral and Maxillofacial Pathology. 2nd ed.. Pennsylvania:Elsevier;2004. 89-

Autosomal dominant

Autosomal recessive

Hypocalcific type

Thickness of enamel

Normal- hypoplasia( middle 3rd of labial surface)

Consistency of enamel

Soft – lost after eruption- scrapped with instrument

Colour of enamel

Newly erupted teeth- dull lustreless opaque, white, honey coloured or yellowish orange or brown

Significance :

Exposed dentin-

hypersensitive

anterior opn

bite

Rapid calculus

formation

Hypocalcified type – aD & AR


Dentition exhibiting diffuse

yellow-brown discoloration .

Note numerous teeth with loss

of coronal enamel except for

the cervical portion.

Hypocalcified type – aD & AR

Extensive loss of coronal

enamel and the similar

density of enamel

and dentin.


Autosomal dominant X linked recessive Autosomal recessive

Hypomaturative type

Commonly in males

Both in primary and permanent dentition

Primary teeth: ground glass opaque white appearance

Permanent teeth :mottled yellow white, may be darkened with absorption of stains

Tight contact point

Enamel approaches normal thickness.

Point of explorer can be forced into enamel

Hypomaturative type – autosomal dominant

Both in primary and permanent dentition

Enamel has milky to shiny, agar brown deeply stained on

contact with exogenous agents

Normal thickness. Chips away around

restoration

Forms large amount of calculus which

may contain pigment forming agents

Teeth may resorb within alveolus

https://www.google.co.in/search?q=amelogenesis+hypomaturative

Hypomaturative type – autosomal recessive

Snow capped

Zone of white opaque enamel on incisal

and

occlusal surface (1/4 to 1/3 of the surface)

Looks like fluorosis

Anteriors, premolars/molars

Both dentitions

https://www.google.co.in/search?q=snow+capped

Hypomaturative type – x linked recessive

Predominant defect – enamel hypomaturation

Enamel appears – mottled yellow-white to yellow brown

Pits are seen frequently on buccal surface of teeth

Radiographically – enamel appears similar to dentin

Large pulp chambers may be seen in single rooted teeth in

addition to varying degrees of taurodontism

Hypomaturation- hypoplastic with taurodontism – Autosomal dominant

https://www.google.co.in/search?q=amelogenesis+hypomatu+tauro

Predominant defect – enamel hypoplasia in which enamel is thin

but also hypomature

Radiographically-

Similar to hypomaturation-hypoplastic variant, except decrease

in thickness of enamel

https://www.google.co.in/search?q=amelogenesis+hypomatu+tauro

Hypoplastic - hypomaturation with taurodontism – Autosomal dominant

Radiographic features

Squarish type of crown being devoid of the normal mesial and distal contours

Normal enamel cap is missing and in its place a thin and opaque layer of enamel

Low or absent cusps, with serrations of varying sharpness

Lack of contrast between enamel and dentin

Obliteration of pulp chamber

Loss of contour Enamel Pulp chamber

https://www.google.co.in/search?q=amelogenesis+tauro

TYPE CLINICAL

APPEARANCE

ENAMEL

THICKNESS

HYPOPLASTIC

(TYPE I)

Crowns size : small to

normal, lack proxmal

contacts, color varies

from normal to opaque

white – yellow brown

Varies from thin and

smooth to normal

thickness with

grooves, furrows

and/or pits

HYPOMATURATIO

N

(TYPE II)

Varies from creamy

opaque to marked

yellow/brown, surface

of teeth soft and rough,

dental sensitivity and

open bite common

Normal thickness

with enamel that

often chips and

abrades easily

around restoration

HYPOCALCIFIE

D

(TYPE III)

Opaque white to

yellow-brown, soft

rough enamel surface,

dental sensitivity and

open bite common,

heavy calculus

formation common

Normal thickness

with enamel that

often chips and

abrades easily

HYPOMATURATIO

N/ HYPOPLASIA/

TAURODONTISM

(TYPE IV)

White/Yellow-

Brown mottled,

teeth can appear

small and lack

proximal contact

Reduced,

hypomineralized

areas and pits

RADIOGRAPHIC

APPEARANCE

INHERITANCE

Enamel has normal

to slightly reduced

contrast/ thin

Autosomal

dominant,

recessive, or X-

linked

Enamel has contrast

similar to or > than

dentin, unerupted

crowns have normal

morphology

Autosomal

dominant,

recessive, or X-

linked

Enamel has contrast

similar to or <

dentin, unerupted

crowns have normal

morphology

Autosomal

dominant, recessive

Enamel contrast

normal to slightly >

dentin, large pulp

chambers

Autosomal dominant


Histopathological examination

Very thin enamel, voids within enamel & composed of laminations of

irregularly arranged enamel prisms

Enamel-dentin junction, show some exaggerated scalloping.

Areas of homogeneous aprismatic enamel or fused indistinct prisms, with

“a reduction in distance between enamel rod incremental lines”

https://www.google.co.in/search?q=amelogenesis+slides

Syndromes associated

Amelogenesi

s imperfect

with

taurodontism

Trichodentoo

sseous

syndrome

Tricho-dento-osseous syndrome. Dentition

exhibiting diffuse enamel hypop lasia and

hypomaturat ion. At birth, the patient

exhibit kinky "steel wool" hair texture

with time, the hair gets straightened.

Taurodontism of the first molar and the

enamel. which is thin and similar in density to

the dentin.


Cone rod dystrophy

Kohlschutter-Tonz syndrome

Usher syndrome

Other syndromes

Non enamel anomalies seen

in Amelogenesis Imperfecta

Delayed tooth eruption

Congenitally missing

teeth

Anterior open bite

Taurodontism

Pulpal calcification

Root and crown

resorption

Hypercementosis

Root malformations

Malocclusion

Gingivitis

Diagnosis

Clinical diagnosis

Cheesy consistency of

enamel with loss of

enamel

Radiographic diagnosis

Missing enamel cap with

low or absent cusp

Differential diagnosis

Dental fluorosis Dentinogenesis imperfecta

Management

Cosmetic

improvement Desensitizing

agent

Prosthetic

rehabilitation

https://www.google.co.in/search?q=amelogenesis+treat+crowns

Reason for choosing this article

Developmental disorder presents with severe dental anomalies. Its important to diagnose the condition as early as possible to balance the decision for early intervention and long-term survival of therestorations. Also consider the social implications for these patients and intervene to relieve their suffering. Thus, this article is anattempt to improve the clinician’s knowledge about the clinical & radiographic diagnosis as well as intervention required for such a condition.

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Education

Amelogenesis imperfecta, hypoplastic type - Dr Sanjana Ravindra