This document discusses genetic conditions that affect dental enamel formation called amelogenesis imperfecta. It describes four main types of enamel defects: hypoplastic (thin enamel), hypomaturation (soft enamel), hypocalcified (soft, friable enamel), and hypomatured/hypoplastic. The types are caused by defects in genes encoding enamel matrix proteins and result in discolored, sensitive teeth prone to disintegration. Amelogenesis imperfecta can be passed through autosomal dominant, recessive or sex-linked inheritance patterns. Diagnosis is based on family history, clinical observations and radiographs. Non-genetic conditions like dental fluorosis can also affect enamel formation.

1. Introduction:
 Genomic conditions affects up dental enamel.
 Teeth affected may be discolored/sensitive or prone to disintegration.
It may show autosomal dominant, autosomal recessive, sex linked and
sporadic inheritance pattern.
 Diagnosis is based on the family history, pedigree plotting and meticulous
clinical observations.
Amelogenesis Imperfecta
Hereditary:
 Hereditary Enamel Dysplasia.
 Hereditary Brown Enamel.
 Hereditary Brown Opalescent Teeth.

2. Types Of Enamel Defects
 Genetic:
 Hypoplastic (Type 1)
 Hypomaturation (Type 2)
 Hypocalcified (Type3)
 Hypomatured/ Hypoplactric (Type 4)
 Differential Interpretation
 Non-Genetic:
 Dental Imperfecta
 Dental Fluorosis
 Chronological Enamel Formation
 Caries
 Attrition
 Abrasion
 Erosion
 Localized Nonhereditary Enamel Hypoplasia
 Localized Nonhereditary Enamel Hypocalcification
 Fluorosis

3. Amelogenesis Imperfecta is a group of conditions caused by defects in the
genes encoding enamel matrix proteins.
Amelogenesis Imperfecta
Type 1: Hypoplastic Amelogenesis Imperfecta:
 The main defect is in formation of the matrix (protein).
 Enamel is not formed to full thickness because ameloblasts fail to lay down
sufficient matrix.
 Enamel is randomly pitted, grooved or very thin, but hard and translucent.
 Affected teeth appear small with open contacts due to very thin or
nonexistent enamel causing thermal sensitivity.
 Teeth are not susceptible to caries unless the enamel is scanty and easily
damaged.
 Commonly in men.

4. Amelogenesis Imperfecta
Type 2: Hypomaturation Amelogenesis Imperfecta
 Occurs during matrix apposition.
 Enamel is softer and chips from the underlying dentin.
 Enamel has a mottled brown-yellow-white color.
 Contact points present as enamel is of normal thickness.
 Radiographically enamel approaches the radio density of dentin.

5. Amelogenesis Imperfecta
Type 3: Hypocalcified Amelogenesis Imperfecta
 Occurs during the calcification stage.
 Most common type.
 Enamel is of normal thickness but soft, friable, and easily lost by attrition.
 Enamel appears dull, lustrous, honey colored and stains easily.

6. Clinical Features– Hypoplastic
Generalized pitted – it appears as thin enamel on teeth
that do not contact each other mesiodistally. Pinpoint to
pinhead pits are randomly distributed over the surface
Localised pitted – horizontal rows of depressions or one
large hypoplastic area with hypocalcification adjacent to
and below the hypoplastic area is found
Diffuse smooth – in this enamel is thin, hard and glossy
with smooth surface
Diffuse rough – enamel is hard with rough granular surface
that may be chipped from underlying dentine, rather than
abrade away as soon with smooth type
Genetic

7. Type 1: Hypoplastic Amelogenesis
Imperfecta

8. Type 2: Hypomaturation Amelogenesis
Imperfecta

9. Type 3: Hypocalcified Amelogenesis
Imperfecta

10. Type 4: Hypomatured/ Hypoplactric
Amelogenesis Imperfecta

11. Clinical features – Hypocalcified
In this, enamel matrix is formed
normally but without significant
mineralization
The enamel is so soft that it can be
removed by prophylactic
instrument
Genetic

12. Clinical Features – Hypomaturation Type
In this there is defect in the maturation of
enamel crystal structure
The enamel can be pierced by an Explorer
point under firm pressure and can be lost
by chipping away from the underlying,
normal appearing dentine
Genetic

13. Differential Interpretation
Squarish type of Crown being devoid of the normal
mesial and distal contours
The normal enamel cap is missing and in its place
there is thin and opaque layer of enamel
Abrasion is advanced then there is obliteration of
pulp chamber
Enamel is less radiolucent than normal
Genetic

14. Non-Genetic
Fluorosis is a cosmetic condition that affects the teeth
It’s caused by overexposure to fluoride during the first eight years of
life. This is the time when most permanent teeth are being formed.
Stains ranging from yellow to dark brown
Surface irregularities
Pits that are highly noticeable
Dental fluorosis