Amelogenesis Imperfecta

1. AmelogenesisAmelogenesis ImperfectaImperfecta

2. Otherwise known as…..Otherwise known as…..
•A IA I
•Hereditary Enamel DysplasiaHereditary Enamel Dysplasia
•Hereditary Brown EnamelHereditary Brown Enamel
•Hereditary Brown Opalescent TeethHereditary Brown Opalescent Teeth

3. What is Amelogenesis Imperfecta ?What is Amelogenesis Imperfecta ?
Amelogenesis Imperfecta represents a Amelogenesis Imperfecta represents a
group of group of hereditary defects of enamelhereditary defects of enamel
unassociated with any other generalized unassociated with any other generalized
defects. It is entirely an defects. It is entirely an ectodermal ectodermal
disturbancedisturbance , since the mesodermal , since the mesodermal
components of the teeth are basically components of the teeth are basically
normal.normal.

4. The term amelogenesis imperfecta is reserved The term amelogenesis imperfecta is reserved
for hereditary defects of enamel that are for hereditary defects of enamel that are not not
associated with defects in other parts of the associated with defects in other parts of the
body or other health problems.body or other health problems. The enamel The enamel
defects are highly variable and include defects are highly variable and include
abnormalities that are classified as hypo abnormalities that are classified as hypo
plastic ,hypo maturation, and hypo calcified. The plastic ,hypo maturation, and hypo calcified. The
enamel in both the hypo maturation and hypo enamel in both the hypo maturation and hypo
calcified AI types is not mineralized to the level calcified AI types is not mineralized to the level
of normal enamel and can be described as hypo of normal enamel and can be described as hypo
mineralized. AI can be inherited as an x-linked, mineralized. AI can be inherited as an x-linked,
autosomal recessive (AR), or autosomal autosomal recessive (AR), or autosomal
dominant (AD) condition.dominant (AD) condition.

5. PrevalencePrevalence
•1 in 700 to 1 in 15,0001 in 700 to 1 in 15,000

6. Etiology
•Dental enamel is a highly mineralized tissue with over
95% of its volume occupied by unusually large, highly
organized, hydroxyapatite crystals. The formation of this
highly organized and unusual structure is thought to be
rigorously controlled in ameloblasts through the
interaction of a number of organic matrix molecules that
include
•enamelin
•amelogenin
•ameloblastin
•tuftelin
•amelotin
•dentine sialophosphoprotein (DSPP;)
•enzymes such as kallikrein and
•matrix metalloproteinase 20 (MMP20)
Any mutations in these proteins can cause AI.

7. A I & D IA I & D I

8. Development of enamel..Development of enamel..
•3 stages.. 3 stages..
formative stageformative stage
deposition of organic matrix.deposition of organic matrix.
Calcification stageCalcification stage
matrix mineralizationmatrix mineralization
Maturation stageMaturation stage
crystallites enlarge and maturecrystallites enlarge and mature

9. A IA I
•3 Types..3 Types..
HypoplasticHypoplastic
HypocalcifiedHypocalcified
HypomaturationHypomaturation
A 4A 4
thth
type of A I is a combination of type of A I is a combination of
hypoplastic & hypomaturation types.hypoplastic & hypomaturation types.

10. Classification of A IClassification of A I
•Based on clinical,histological,&genetic Based on clinical,histological,&genetic criteria-criteria-Witkop & SaukWitkop & Sauk
HypoplasticHypoplastic
Pitted, ADPitted, AD
Local, ADLocal, AD
Smooth, ADSmooth, AD
Rough, ADRough, AD
Rough, ARRough, AR
Smooth, X-linked dominant Smooth, X-linked dominant

HypocalcifiedHypocalcified
DiffuseDiffuse ADAD
Diffuse ARDiffuse AR
HypomaturationHypomaturation
Diffuse , X-Linked recessiveDiffuse , X-Linked recessive
Diffuse Pigmented, ARDiffuse Pigmented, AR
Snow-capped teeth, X-linkedSnow-capped teeth, X-linked
Combination Type Combination Type
Hypomaturation-hypoplastic with taurodontism,ADHypomaturation-hypoplastic with taurodontism,AD
Hypoplastic-hypomaturation with taurodontism,AD Hypoplastic-hypomaturation with taurodontism,AD

11. Clinical features..Clinical features..
•Hypoplastic Type.Hypoplastic Type.

The enamel is The enamel is notnot formed to formed to full normal full normal
thicknessthickness

15. Hypocalcified Type.Hypocalcified Type.
•The enamel is so The enamel is so softsoft that it can be that it can be
removed by a prophylaxis instrument.removed by a prophylaxis instrument.
•Yellow brown or orange on eruption, Yellow brown or orange on eruption,
stained brown to black with time.stained brown to black with time.
•Exhibits rapid calculus apposition.Exhibits rapid calculus apposition.
•Coronal enamel lost with function, except Coronal enamel lost with function, except
for the cervical portion which is for the cervical portion which is
mineralized better.mineralized better.
•Autosomal recessive—more severe.Autosomal recessive—more severe.

18. Hypomaturation Type.Hypomaturation Type.
•The enamel can be The enamel can be pierced by an explorer pierced by an explorer
pointpoint under firm pressure under firm pressure
•can be lost by can be lost by chippingchipping away from the away from the
underlying normal appearing dentin.underlying normal appearing dentin.
•Teeth are normal in shape, but exhibit a Teeth are normal in shape, but exhibit a
mottled , opaque white brown yellow mottled , opaque white brown yellow
discoloration.discoloration.
•Snow capped pattern- exhibit a zone of Snow capped pattern- exhibit a zone of
white opaque enamel on the incisal or white opaque enamel on the incisal or
Occlusal third of the crown.Occlusal third of the crown.

22. Other features…Other features…
•Both dentitions are affectedBoth dentitions are affected
• In Some cases teeth may appear normal, in In Some cases teeth may appear normal, in
others may be extremely unsightly.others may be extremely unsightly.
•Color of the crown can vary from yellow to dark Color of the crown can vary from yellow to dark
brown.brown.
•Enamel might have numerous parallel vertical Enamel might have numerous parallel vertical
wrinkles or grooves.wrinkles or grooves.
•Open contact pointsOpen contact points
•Occlusal surfaces and incisal edges are Occlusal surfaces and incisal edges are
frequently abradedfrequently abraded

23. Radiographic FeaturesRadiographic Features
•The enamel may appear totally absent The enamel may appear totally absent
•When present may appear as a thin layer , When present may appear as a thin layer ,
chiefly over the tips of the cusps & on the chiefly over the tips of the cusps & on the
interproximal surfaces.interproximal surfaces.
•In some cases calcification is so much In some cases calcification is so much
affected that enamel & dentin seem to affected that enamel & dentin seem to
have the same radio density, making have the same radio density, making
differentiation between the two difficult.differentiation between the two difficult.

25. Histological FeaturesHistological Features
•Hypoplastic type—disturbance in the Hypoplastic type—disturbance in the
differentiation or viability of ameloblasts.differentiation or viability of ameloblasts.
•Hypocalcification type– defects of matrix Hypocalcification type– defects of matrix
structure and of mineral deposition.structure and of mineral deposition.
•Hypomaturation type– alteration in enamel Hypomaturation type– alteration in enamel
rod & rod sheath structures.rod & rod sheath structures.

26. Management Management
•Treatment depends on the specific AI type Treatment depends on the specific AI type
and the character of the affected enamel.and the character of the affected enamel.

•Treatments range from preventive care Treatments range from preventive care
using sealants and bonding for esthetics using sealants and bonding for esthetics
to extensive removable and fixed to extensive removable and fixed
prosthetic reconstruction. prosthetic reconstruction.

27. Treatment of hypoplastic typeTreatment of hypoplastic type
•Therapy for the hypoplastic AI types typically Therapy for the hypoplastic AI types typically
involves the use of bonding procedures to involves the use of bonding procedures to
protect the malformed teeth from caries and protect the malformed teeth from caries and
improve esthetics. improve esthetics.
•Hypoplastic teeth usually have reasonably well Hypoplastic teeth usually have reasonably well
mineralized enamel, albeit thin and/or pitted, mineralized enamel, albeit thin and/or pitted,
making them suitable for restorative therapies making them suitable for restorative therapies
involving bonding to the enamel .involving bonding to the enamel .
•Composite resin or porcelain veneers can be Composite resin or porcelain veneers can be
bonded to the anterior teeth when the incisor bonded to the anterior teeth when the incisor
shape, size and/or color requires modification.shape, size and/or color requires modification.

28. Continued…..Continued…..
•Orthodontic therapy may be used to partially Orthodontic therapy may be used to partially
close the interdental spaces prior to restoration close the interdental spaces prior to restoration
in those individuals having small square shaped in those individuals having small square shaped
incisors and interdental spacing that is too incisors and interdental spacing that is too
excessive to close with restorative therapy excessive to close with restorative therapy
alone. alone.
•Individuals with hypoplastic AI often can retain Individuals with hypoplastic AI often can retain
intracoronal restorations such as amalgams and intracoronal restorations such as amalgams and
composite resins.composite resins.
•if the enamel is extremely thin and malformed if the enamel is extremely thin and malformed
the teeth can require full dental coverage with the teeth can require full dental coverage with
crowns. crowns.

29. Porcelain veneers

30. Treatment of hypocalcified & Treatment of hypocalcified &
hypomaturation typeshypomaturation types
•The hypomaturation and hypocalcified AI types The hypomaturation and hypocalcified AI types
can be restored with conventional approaches if can be restored with conventional approaches if
the enamel is not severely involved.the enamel is not severely involved.
•if enamel is severely hypomineralized and of if enamel is severely hypomineralized and of
insufficient strength to retain bonded or insufficient strength to retain bonded or
intracoronal restorations, full coverage intracoronal restorations, full coverage
restorations should be placed.restorations should be placed.
• In cases of severely hypomineralized enamel, In cases of severely hypomineralized enamel,
stainless steel crowns are indicated in the stainless steel crowns are indicated in the
primary and early permanent dentitions. primary and early permanent dentitions.

31. Continued…Continued…
•stainless steel crowns with composite inserts or stainless steel crowns with composite inserts or
composite crowns that are retained both by composite crowns that are retained both by
mechanical undercuts and bonding can greatly mechanical undercuts and bonding can greatly
reduce tooth sensitivity and provide reasonable reduce tooth sensitivity and provide reasonable
esthetics. esthetics.
•The dentist should not rely on retention from The dentist should not rely on retention from
bonding alone in those cases with very weak bonding alone in those cases with very weak
and poorly mineralized enamel. and poorly mineralized enamel.

32. Continued….Continued….
•Resin crowns can be placed on permanent incisors soon Resin crowns can be placed on permanent incisors soon
after they begin to erupt during the mixed dentition after they begin to erupt during the mixed dentition
(about age 7 – 10 years). As the gingival margin (about age 7 – 10 years). As the gingival margin
becomes exposed during continued tooth erupt the becomes exposed during continued tooth erupt the
resins are easily modified by adding resin to the gingival resins are easily modified by adding resin to the gingival
margin of the tooth.margin of the tooth.
•Ultimately, porcelain fused to metal or other custom Ultimately, porcelain fused to metal or other custom
fabricated crowns can be placed on the dentition. This fabricated crowns can be placed on the dentition. This
may be delayed until late adolescence or early adulthood may be delayed until late adolescence or early adulthood
when all the teeth are present, the teeth are fully when all the teeth are present, the teeth are fully
erupted, and the gingival height around the teeth has erupted, and the gingival height around the teeth has
stabilized. stabilized.
•While costly, these types of restorations can allow even While costly, these types of restorations can allow even
severely affected dentitions to be treated and achieve severely affected dentitions to be treated and achieve
excellent function and esthetics. excellent function and esthetics.

35. •The severely affected individual shown in Figure had AR The severely affected individual shown in Figure had AR
Hypomaturation AI and was treated over several years Hypomaturation AI and was treated over several years
with stainless steel crowns, orthodontics, orthognathic with stainless steel crowns, orthodontics, orthognathic
surgery and eventually porcelain fused to metal crowns surgery and eventually porcelain fused to metal crowns
to achieve this excellent result.to achieve this excellent result.