Developmental Disturbances of Hard Tissues (4).pdf

Developmental disturbance of oral cavity

1. Developmental Anomalies Of
Oral & Para-oral Structures

2. Index
Introduction
Types of anomalies
Developmental anomalies of Oro-facial hard
tissues
Developmental anomalies of Oro-facial soft
tissues
Syndromes

3. Introduction
Malformation or defects resulting from
disturbance of growth & development are
known as Developmental Anomalies

Manifestation of defects are evident either at
birth or some times after birth

4. Types of anomalies
Congenital developmental anomalies
Hereditary developmental anomalies
Familial developmental anomalies
Acquired developmental anomalies
Hamartomatous developmental anomalies
Idiopathic developmental anomalies

5. Congenital Developmental
Anomalies
Defects which are present at birth or before birth
during the intra-uterine life as a result of either
heredity or environmental influences
E.g. - Cleft lip & palate

6. Hereditary Developmental Anomalies
Defects are genetically transmitted from the parents to
the offspring, where definite genetic location is identified

E.g.
Downs syndrome –Trisomy 21

7. Familial Developmental Anomalies
Defects are transmitted from the parents to the
offspring, where definite genetic location is not
identified
E.g. – Diabetes

8. Acquired Developmental Anomalies
Defects develop during intra-uterine life due to some
pathological environment condition

Can be Prenatal / neonatal / Postnatal
E.g.:
1. Congenital Syphilis
- Notched incisors
- Mulberry molars
2. Fluorides
- Enamel hypoplasia

9. Fluorosis
Notched incisors Mulberry molars

10. Hamartomatous Developmental Anomalies
Defects occuring due to hamartomatous change in the
tissues

Hamartoma:
Excessive focal proliferation of normal tissues which are
native to that particular location
E.g. – Odontome

12. Note:
Choristoma:
Excessive focal proliferation of normal tissues which are
not native to that particular location
E.g. – Gingival salivary gland choristoma

Teratoma:
Tumor arising from all the 3 germ layers
E.g. – Ovarian teratomas

13. Idiopathic developmental anomalies
Indicates the developmental anomalies were exact
cause is unknown

E.g. – Idiopathic enamel hypoplasia

14. Syndrome
The term syndrome derives from the Greek and means
literally "run together “

A group of symptoms that collectively indicate or
characterize a disease, a psychological disorder, or
another abnormal condition

Large number of syndromes occur in association with
many oral diseases

Early diagnosis of a syndrome is important since
severity of a disease can be much more when it is
occuring in association with a syndrome

15. E.g.
Gardner's syndrome
Multiple polyposis of large intestine
Osteomas of bone
Desmoid tumours
Multiple epidermoid cysts of skin
Multiple impacted supernumerary tooth

16. Developmental anomalies of
Oro-facial hard tissues

17. 1.Developmental Anomalies affecting the teeth


2.Developmental Anomalies affecting the jaws

18. Anomalies of tooth occur either due to genetic /
environmental factors

Defects may occur during any of the
developmental stages of teeth, which are
manifested clinically in the later life once the
tooth is fully formed

19. Developmental Anomalies of
Teeth

20. Initiation - Anodontia/ hyperdontia
Proliferation - Microdontia
Histodifferentiation - Cysts / neoplasms
Morphodifferentation - teeth with abnormal
morphology or Odontome
Apposition - Hypoplastic tooth
Calcification - Hypocalcification
Eruption - Embedded tooth
E.g.
Structural
diffects

21. Classification

22. I. Those affecting the size
Microdontia
Macrodontia
Rhizomicri
Rhizomegaly

23. II. Those affecting the number
Anodontia
Supernumerary teeth
Pre-deciduous dentition
Post permanent dentition

24. III. Those affecting the shape
Gemination
Fusion
Concrescence
Talon’s cusp
Dens invaginatus
Dens evaginatus
Taurodontism
Dilaceration / Flexion
Supernumerary root
Extra cusps
Enamel pearl
Cervical enamel extension

25. IV. Those affecting the position
Ectopia
Rotation
Trans-position
Inversion
Trans-migration

26. V. Those affecting eruption
Premature eruption
Delayed eruption
Impacted tooth
Embedded tooth
Submerged tooth
Eruption sequestrum

27. VI. Those affecting the structure
Enamel
Enamel hypoplasia
Amelogenesis imperfecta
Dentin
Dentinogenesis imperfecta
Dentin dysplasia
Enamel + Dentin
Regional odontodysplasia
Cementum
Hypocementosis
Hypercementosis

28. Microdontia
Condition in which one or more teeth are smaller than
normal
More in females

Etiology
 Genetic factors
 Environmental factors
Types
1. Generalized microdontia (>14)
- True
- Relative
2. Focal microdontia (<14)

29. True generalized microdontia
All the teeth in both arches are well formed but, uniformly
smaller than normal

Associated with
- Pituitary dwarfism
- Down‟s syndrome
- Congenital heart disease

30. Relative generalized microdontia
Large jaw size relative to the teeth makes the normal
teeth seem smaller resulting in spacing between teeth
Hereditary condition

31. True generalized microdontia

32. Relative generalized microdontia

33. Focal microdontia
One or more teeth are smaller than normal
More common than generalized microdontia
Frequently involved teeth are maxillary laterals &
maxillary 3
rd
molars

E.g. – Peg laterals

34. Focal microdontia

35. Macrodontia (Megadontia / Megalodontia)
Condition in which one or more teeth are larger than
normal
Common in males
Teeth are known as megadont / macrodont
Types
1. Generalized macrodontia
- True
- Relative
2. Localized macrodontia

36. Macrodontia

37. True generalized macrodontia
All the teeth in both arches are well formed & uniformly
larger than normal

Associated with
- Pituitary gigantism

38. Relative generalized macrodontia
Small jaw size relative to the teeth makes the normal
teeth seem larger resulting in crowding of teeth
Hereditary condition

39. Localized macrodontia
One or more teeth are larger than normal
Should not be confused with fusion

Associated with
- Facial hemi-hypertrophy

40. Localized macrodontia

41. Rhizomicri
It is a condition where root of the teeth are smaller than
normal
Teeth most commonly affected are maxillary laterals,
maxillary 3
rd
molars, maxillary & mandibular 1
st

premolars

Clinical significance
•Involved tooth cannot be used as anchorage &
abutment

42. Rhizomegaly (Radiculomegaly)
Condition where in root of the teeth is larger than
normal
Most commonly affected teeth are maxillary &
mandibular cuspids

Clinical significance
- Extraction difficulties
- Oro-antral fistula

43. Rhizomicri Rhizomegaly Normal

44. Anodontia
Condition in which there is absence of teeth in the oral
cavity

Etiology:
- Hereditary factor
- Familial tendency
- Radiation injury to developing tooth germs
- Hereditary ectodermal dysplasia
- Mutation

45. Types
Pseudo anodontia

46. Pseudo anodontia
Condition in which teeth are present within the jaw
bones but are not erupted

E.g.
- Impacted tooth
- Embedded tooth

47. False anodontia
Condition in which the teeth are missing in oral cavity
due to extraction or exfoliation

48. True anodontia
Condition which occurs due to failure of development
of tooth in the jaw bones

Can be total or partial

49. Complete / Total anodontia
Congenital absence of all teeth

Extremely rare condition

50. Partial anodontia
Congenital absence of one or more teeth

Commonly seen in third molars, maxillary lateral
incisors and the second premolars

51. Hypodontia
Congenital absence of one or more teeth but less than 6

52. Oligodontia
Congenital absence of more than 6 teeth

53. Conditions & syndromes associated
Hereditary ectodermal dysplasia
Ehlers – Danlos syndrome
Rieger‟s syndrome
Down syndrome
Book syndrome

54. Supernumerary teeth (Hyperdontia)
Presence of tooth in excess of the normal number in the
dental arch
Common in males

Etiology:
- Accessory tooth bud
- Splitting of the regular normal tooth bud
- Hereditary
- Hyperactivity of dental lamina

55. Classification
I. Based on Number & Shape
Supernumerary
teeth
Single
Multiple
Conical
Complex
Tuberculate
Supplemental
Non-syndrome
associated
Syndrome associated
Compound

56. II. Based on location
Mesiodens
Distomolar / Destodens
Paramolar

57. Mesiodens
Most common type of supernumerary tooth
Located between the upper central incisors
Small conical in shape
Erupted / impacted / inverted

58. Mesiodens

59. Distomolar (Distodens)
Small rudimentary tooth
Located distal to 3
rd
molars in the dental arch

60. Paramolar
Small rudimentary tooth
Located on buccal / lingual aspect of the normal molars
Occurs most commonly in maxilla

61. Supplemental tooth

62. Distomolar

65. Clinical significance
Crowding, malocclusion & aesthetic problems
May lead to increased incidence of dental caries &
periodontal problems
Dentigerous cyst may develop from impacted
supernumerary tooth

Treatment:-
Extraction

66. Conditions & syndromes associated
Cleido cranial dysplasia
Apert syndrome
Gardner syndrome (multiple supernumerary teeth)
Ehlers Danlos syndrome
Down‟s syndrome
Cleft lip & palate

67. Predeciduous dentition
Infants occasionally are born with structures which
appear to be erupted teeth

Earlier thought to arise from accessory bud from
accessory dental lamina & the concept is no more in
use

Now thought as hornified epithelial structures filled
with keratin occurring on gingiva on crest of ridge &
are termed as „dental lamina cyst of new born‟

68. Postpermanent dentition
It is a condition in which several teeth erupt into oral
cavity after all permanent teeth are lost particularly
after the insertion of full denture

Earlier it was thought to be the third dentition

Now it is regarded as the delayed eruption of
embedded or impacted permanent teeth or it can be
eruption of multiple supernumerary unerupted teeth

69. Those affecting the shape

70. Gemination
It‟s a developmental anomaly which refers to the
incomplete formation of 2 teeth resulting from an
attempt at division single tooth germ by an
invagination.
The result is formation of two completely or
incompletely separated crown that have single root
and root canal.
Affects both deciduous & permanent dentition
Commonly affects deciduous mandibular incisors &
permanent maxillary incisors

71. Clinically the tooth reveals
extremely widened crown
with indentation / groove as a
mark of attempted division

Gemination consist of same
number of teeth (32) in oral
cavity

72. Twinning
It‟s a developmental anomaly in which there is complete
& equal division of single tooth germ resulting in one
normal & one supernumerary tooth

Twinning consist of one extra tooth (may be 33) in the
oral cavity

73. Fusion
It is defined as the union of 2 adjacent normally
separated tooth germs
It results in one anomalous large crown in place of two
normal teeth. The teeth are fused at the level of dentin
If fusion occurs before the calcification begins
complete fusion with single crown and root develops
If it happens after crown completion resuting tooth will
have union of roots only

74. Affects both deciduous & permanent dentition
Incisor teeth are frequently affected
Fusion may be complete or incomplete.
Physical force or pressure produces the contact
between the adjacent tooth germs

75. Types
Fusion consist of one teeth less (31) in the oral
cavity
Fusion
Complete Incomplete
Fusion takes place before
calcification of tooth has
occurred
Fusion begins at
later stages of tooth
development & may
be limited to roots
only

77. Concrescence
Developmental anomaly where the roots of 2 or more adjoining
teeth have been united by cementum

It occurs after root formation of involved teeth are completed

Causes:
- Traumatic injury
- Crowding of teeth
- Hypercementosis associated with chronic inflammation

78. Occurs frequently between maxillary 2
nd
& 3
rd
molars

Clinical significance:-
–Difficulty in extraction

80. Dilaceration (Flexion)
Refers to a sharp bend / curve / angulation in
root or crown of tooth

Etiology:-
- Trauma
- Injury to deciduous tooth
- Idiopathic

81. Pathogenesis
Trauma
Partially calcified tooth germ
Displacement of hard calcified
crown portion of tooth
Uncalcified root portion develops
by forming an angle

82. More common in maxillary incisors
Curve may be present at apical / middle / cervical
portion of root depending on the portion which is
forming at the time of trauma

Clinical significance:-
Difficulties in extraction & RCT

84. Talon cusp
Anomalous projection or additional cusp arising lingually from
cingulum area & extends to the incisal edge as a prominent “T”
shaped projection

Common in permanent dentition & rare in deciduous dentition

Seen commonly on permanent maxillary incisors (more in
laterals) and less frequently on mandibular incisors

Forms a stucture resembles an eagle‟s talon

Causes:-
- Local environmental factors
- Genetic factors

86. Clinical significance
Talon cusp consist of normally appearing enamel &
dentin. In few cases there can be presence of vital
pulp tissue

Usually asymptomatic

May interfere with occlusion

Susceptibility to caries (lingual pits)

87. Treatment:-
- Restoration of lingual pits to prevent dental caries
- Reduction of cusp if it interferes with occlusion

Syndromes associated:-
1. Rubinstein – Taybi syndrome
2. Sturge – Weber syndrome
3. Mohr syndrome

88. Dens invaginatus
Dens – in – Dente
Tooth – with in – Tooth
Pregnant tooth
Dilated composite odontome

89. Developmental morphologic variation characterized by
deep surface invagination of the crown / root

Presence of enamel lined cavity within tooth led the
early investigators to believe that a tooth with in a
tooth & hence the name “Dens – in – Dente”

The condition is most probably caused by an
invagination of enamel organ before calcification

90. Types
Based on occurrence
Coronal Radicular
Dens invaginatus
Invagination / infolding
occurs on crown portion
of the tooth
Invagination / infolding
occurs on root portion
of the tooth

91. Coronal dens invaginatus

Type I / Mild form
Invagination confined to crown within the CEJ

Type II / Intermediate form
Invagination extends below CEJ; may or may not
communicate with pulp

Type III / Extreme form
Invagination extend beyond the pulp through the root
& perforate the apical / lateral radicular area without
any communication with the pulp

92. Type I Type II Type III

93. More common is coronal type

Common in permanent maxillary teeth

Commonly affected teeth are maxillary laterals, central incisors
& premolars

Before eruption the invagination is filled with soft tissue which is
similar to dental follicle, which on eruption becomes necrotic

95. Radicular dens invaginatus
Rare condition
Thought to arise secondary to a proliferation of HERS,
with the formation of a strip of enamel that extends
along the root surface
The root reveals an invagination with the opening on the
lateral aspect of the root

97. Radiographic feature
Affected tooth demonstrates an enlargement with
deep pear shaped invagination lined by enamel

99. Clinical significance
The invagination is extremely prone to caries

Type III form of Dens invaginatus provides direct
communication between oral cavity & periapical
tissues leading to inflammatory lesions

Treatment:-
Early detection & prophylactic restoration

100. Dens Evaginatus
Leong‟s premolar
Evaginated odontome
Occlusal tuberculated premolar
Occlusal enamel pearl
Central tubercle

101. Developmental anomaly of the tooth in which a focal
area of the crown shows a „globe‟ or „nipple‟ shaped
outward projection on the occlusal surface

Clinically appears as an extra cusp

Common in individuals of Mongolian origin & rare in
whites

102. Pathogenesis
Develops as a result of localized elongation &
proliferation of inner enamel epithelium as well as the
dental papilla into the dental organ

103. Clinical features
Primarily affects the premolars (Molars also)
Usually bilateral with mandibular predominance
Presents as an extra cusp located on the occlusal
surface between buccal & lingual cusps
Can interfere with tooth eruption
Causes occlusal disharmony
Sometimes, the extra cusp may contain vital pulp and
its attrition / facture may result in pulp exposure leading
to associated complications & pain

105. Note
Shovel shaped incisors
–Variant of Dens Evaginatus
–Prominent marginal ridges which creates a hollowed
lingual surface resembling a scoop of a shovel

106. Treatment
Asymptomatic – No treatment needed

Occlusal disharmony – Minor reduction

Pulp exposure – RCT

107. Taurodontism (Bull teeth)
Developmental anomaly in which the crown portion of the
tooth is enlarged at the expense of the roots.

Term coined by Sir Arthur Keith

Was found commonly in ancient neanderthal man

The overall shape resembles that of the molar teeth of cud-
chewing animals (Tauro = Bull, Dont = tooth)

There is altered crown-to-root ratio

109. Causes
Failure of hertwig‟s epithelial root sheath to invaginate at
proper horizontal level during development of teeth

Primitive pattern

Atavism

Mendelian recessive trait

Mutation resulting from odontoblastic deficiency during
dentinigenesis of roots

110. Clinical & radiographic features
Affects permanent teeth more frequently than
deciduous teeth
Unilateral or bilateral
Molars are frequently involved
Teeth are usually rectangular in shape
Minimal constriction at cervical area
Elongated crown & enlarged pulp chamber
Apically placed furcation area
Exceedingly short roots

111. Types
1. Hypotaurodont (Mild)
Furcation area placed below normal but within
cervical 1/3
rd
of root
2. Mesotaurodont (Moderate)
Furcation area placed at middle 1/3
rd
of root
3. Hypertaurodont (Severe)
Furcation area placed at apical 1/3
rd
of root
Based on degree of apical displacement of
pulpal floor / furcation area (by Shaw)

112. Mild moderate severe Normal

114. Syndromes associated
Klinefelter‟s syndrome
Down syndrome
Poly X syndrome
Ectodermal dysplasia

115. OTHERS
Cervical enamel extensions
Enamel pearl
Conical incisors ( peg shaped laterals)
Hutchinsons incisors, Moon‟s Molar, Mulberry molars e

Accessory roots
Accessory cusps & ridges
–( Cusp of carabelli)
–Paramolar tubercle/ Bolk cusp/ Protostylids

116. Supernumerary root
Refers to the presence of one or more extra roots than
normal
Roots may be curved / straight / divergent
Affects both deciduous & permanent dentition
Commonly involved teeth are permanent molars,
mandibular cuspids & premolars

Clinical significance:-
Difficulties in extraction & RCT

118. Enamel pearl
Enameloma
Enamel drops / nodule
Enamel exostoses

119. These are white dome shaped calcified projections of
enamel located at the furcation areas of molar teeth

They may consist entirely of enamel or contain
underlying dentin & pulp

120. The epithelial component of the hertwigs root sheath
may sometimes retain its ameloblastic potential and
may synthesize enamel in some focal areas on root
surface

Localized bulging of odontoblastic layer

From small group of misplaced ameloblasts
Causes

121. Clinical features
Affects both deciduous & permanent dentition
Occur single / multiples
Commonly seen on roots of maxillary molars followed
by mandibular molars
Highest incidence in Asians

Types:-
1. Extradental (on root surface)
2. Intradental (included in dentin)

122. Clinical significance
Exophytic nature of the pearl is conducive to inadequate
cleaning & plaque retention

123. Cervical enamel extensions
These are triangular extensions of enamel from CEJ
towards furcation area of molar teeth

Common in mandibular molars

Frequently involve bifurcation area on buccal surface
of roots

125. Classification
Type I
Coronal enamel projecting just below CEJ

Type II
Coronal enamel projecting below CEJ but not involving
the furcation area

Type III
Coronal enamel extending to involve the furcation area

126. Enamel extensions lead to loss of PDL attachment and
may predispose to development of:

1. Periodontal pocket
2. Buccal bifurcation cyst
Clinical significance

127. Disturbance in position
Ectopia
Trans position
Trans migration
Rotation

128. Ectopia
Remote location of a tooth away from its normal position

E.g:-
1. Maxillary canine erupting in nasal cavity / maxillary
sinus / at the inner canthus of eye
2. Mandibular 3
rd
molar erupting at angle of mandible /
lower border of mandible / through the skin of cheek

130. Transposition
Condition where in 2 teeth exchange position

E.g:-
1.Exchange of position between maxillary canine
& premolar
2.Exchange of position between mandibular canine
& lateral incisors

132. Rotation
Developmental anomaly where in a tooth turns
partially / completely

Commonly seen in,
Maxillary 2
nd
premolar (Complete rotation)
Maxillary central & 1
st
premolar (Partial rotation)

134. Disturbance in eruption and
exfoliation
Premature eruption
Delayed eruption
Unerupted teeth
Embedded or impacted teeth
Ankylosed teeth
Eruption cyst, eruption hematoma, & eruption
sequestrum
Premature exfoliation

135. Delayed eruption
Tooth erupts into oral cavity
much later than normal time of
eruption


Affects both deciduous &
permanent dentition

136. Premature eruption
Tooth erupts into oral cavity
much earlier than normal time
of eruption


Frequently involved tooth are
deciduous mandibular central
incisors

137. Types
Natal teeth
Erupted deciduous teeth present at the time of birth

Neonatal teeth
Deciduous teeth which erupt within first 30 days of life

138. Causes
Endocrinal disturbances
- Adreno-cortical syndrome
- Hyperthyroidism



Premature loss of deciduous teeth causes premature
eruption of permanent teeth

139. Systemic factors
- Rickets
- Cleidocranial dysplasia
- Cretinism

Local factors
- Fibromatosis gingivae
- Cleft lip & palate
- Retained deciduous tooth
Idiopathic
Causes

140. Impacted teeth
Teeth which are prevented from eruption into oral cavity
by some physical barrier in eruptive path or non
availability of space

Causes
- Micrognathia
- Retained deciduous teeth
- Supernumerary teeth
- Odontogenic cyst & tumors
- Cleft palate
- Syndrome associated

141. Classification
Completely impacted tooth
Impacted tooth is totally surrounded by bone


Partially impacted tooth
Impacted tooth is partly surrounded by bone & partly by soft
tissue

142. Mesioangular : Impacted tooth mesially inclined

Distoangular : Impacted tooth distally inclined

Vertical : Impacted tooth lies vertical

Horizontal : Impacted tooth lies horizontal

144. Complications
Crowding
Malocclusion
Pericoronitis
Radiating pain
Root resorption of adjacent erupted teeth
Caries
Food impaction & halitosis
Dentigerous cyst

Treatment:-
- Removal of cause
- Surgical removal

145. Embedded teeth
It refers to those teeth that are unerrupted due to lack
of eruptive forces

146. Submerged teeth
It refers to ankylosed deciduous teeth

Frequently involved teeth are deciduous molars

Occlusal table of the ankylosed deciduous tooth is
located below the occlusal plane of the rest of the
permanent teeth in the arch giving an submerged
appearance

In such cases the underlying permanent tooth may
become impacted or may erupt either buccally /
lingually

148. Disturbance in structure of teeth

149. MNR Dental College & Hospital



Topic: DEVELOPMENTAL
DISTRUBANCES

Sr LEC: Dr NIROSHA

150. ENAMEL HYPOPLASIA
Defect of enamel due to disturbance during its formative
process

During the formative stages of enamel, the ameloblast
cells are susceptible to various factors which can
disturb the process and the effect of which are reflected
on the surface enamel after the eruption of tooth

151. Types
Based on causative factors:
Enamel hypoplasia
Hereditary
(Amelogenesis Imperfecta)
Environmental
Focal
(Turners hypoplasia)
Generalized

152. Differences between hereditary &
environmental enamel hypoplasia
Hereditary
1.Both dentition affected


2.Only enamel is affected


3.Affected tooth shows
diffuse or vertical
orientation of defects

Environmental
1.Either one dentition
affected


2.Affects enamel and other
calcified structures


3.Affected tooth shows
defects, which are
horizontally arranged

153. Hereditary enamel hypoplasia

154. Amelogenesis imperfecta
Hereditary enamel dysplasia
Hereditary brown enamel
Hereditary brown opalescent tooth

155. Genetic defect
– with Enamelin gene ( ENAM)
- Gene coding amelogenin protein (AMELX)

Location of defective gene
–Autosomal form is less understood
–in X – linked AI defective gene is closely linked to
locus DXS85 at Xp 22 ( general location of gene for
amelogenin)

156. It is a heterogenous group of hereditary disorders of
enamel formation

Entirely an ectodermal disturbance.

The condition involves only the enamel while dentin,
cementum & pulp remain normal

157. Types
Amelogenesis imperfecta may set in during any stage
of enamel formation . Based on that there are 4 types

1.Hypoplastic type - Defective matrix deposition
2.Hypocalcification type – Defective calcification
3.Hypomaturation type- Defective maturation
4. Hypomaturation-hypoplastic with taurodontism

158. Classification
by Witkop (1989)


TYPE I Hypoplastic type

IA Pitted, autosomal dominant
IB Local, autosomal dominant
IC Local, autosomal recessive
ID Smooth, autosomal dominant
IE Smooth, X- linked dominant
IF Rough, autosomal dominant
IG Enamel agenesis, autosomal recessive

159. TYPE II Hypomaturation type
IIA - Pigmented autosomal recessive
IIB - X- linked recessive
IIC - Snow capped tooth, Autosomal dominant
TYPE III Hypocalcification type
IIIA - Autosomal dominant
IIIA - Autosomal recessive

160. TYPE IV Hypomaturation-hypoplastic with
taurodontism

IVA - Hypomaturation-hypoplastic with
taurodontism, Autosomal Dominant
IVB - Hypoplastic-Hypomaturation with
taurodontism, Autosomal Dominant

161. Clinical features

162. Hypoplastic type
The disease affects the stage of matrix formation
Teeth exhibit complete absence of enamel or there may
be presence of enamel on some focal areas
Enamel thickness is usually below normal
Quantity is affected, but quality of formed enamel is
normal
Tooth appears as though prepared for receiving a
prosthetic crown

163. Hypocalcification type
The disease affects the stage of early mineralization
Enamel is of normal thickness (quantity not affected)
Tooth is normal in shape on eruption, but the enamel is
lost very easily
Enamel is soft & can be easily removed with a blunt
instrument
Enamel is yellowish brown on eruption

164. Hypomaturation type
The disease affects the stage of maturation
Enamel is of normal thickness (quantity not affected)
Teeth are normal in shape but enamel is opaque white
or brownish in colour
Enamel does not have normal hardness & translucency
and tend to chip off easily
It can be pierced with an explorer tip with firm pressure

166. Snow capped teeth
It is the mildest form of hypomaturation type of
amelogenesis imperfecta.
Affects both 1
0
& 2
0
dentitions.
Most cases demonstrate an X linked pattern of
inheritance
The enamel is of near normal hardness & has a zone of
white opaque enamel on the incisal or occlusal one
quarter to one third of crown.
Demonstrates an anterior to posterior distribution and
have been compared to a denture dipped in white paint

168. Radiological features
The thickness & radio density of enamel varies greatly

Hypoplastic type
Enamel may appear totally absent or as a thin line
Radiodensity of affected enamel is similar to that of normal
enamel (greater than dentin)

Hypocalcification type
Radiodensity of affected enamel is much lesser than that of
normal enamel
Hypomaturation type
Radiodensity of affected enamel is lesser than that of normal
enamel and is equivalent to normal dentin

170. Histopathology
Hypoplastic type
Lack of differentiation of ameloblast cells with little or no
matrix formation

Hypocalcification type
Abnormal matrix structure & mineral deposition

Hypomaturation type
Alteration in the enamel rod & rod sheath structures

171. Treatment
No definitive treatment

Veneering or capping of teeth to improve esthetics

172. Environmental enamel hypoplasia

173. Focal enamel hypoplasia
Also known as Turner’s hypoplasia
Most common form of enamel hypoplasia
Occurs due to trauma or infection to deciduous
teeth affecting the developing permanent tooth
Usually affects single tooth & is called as
Turners tooth

174. Hypoplasia ranges from a mild, brownish discolouration
to a severe pitting of enamel surface on the labial
aspect
Frequently involved teeth are permanent
maxillary/mandibular bicuspids & maxillary incisors
Severity of hypoplasia depends on severity of infection,
degree of tissue involvement and stage of tooth
formation

175. Pathogenesis
Deciduous teeth
Trauma Periapical Infection
Affect the ameloblastic layer
of permanent tooth
Disturb the enamel formation
Enamel defects

176. Clinical features
Affected area of tooth appear as a zone of white or
yellow brown discoloration & pitted areas

177. Generalized enamel hypoplasia
The ameloblasts in the developing tooth germ are
sensitive to external stimuli

Any systemic or environmental disturbance can result in
abnormalities in enamel formation which manifests as
defects on the surface of tooth

It affects numerous teeth which are being formed at the
time of disturbance

178. Clinically the defects can manifests as
1. Hypoplasia
2. Diffuse opacities
3. Demarcated opacities

Most often it manifests as a horizontal line of enamel
hypoplasia with pits & grooves

179. The line on the tooth surface indicates the zone of enamel
hypoplasia

The location of the line corresponds with the developmental
stage of affected tooth & width indicates the duration of the
disturbances

180. Causes
Prenatal
Infections (Rubella, Syphilis)
Malnutrition, Metabolic & Neurological disorders during pregnancy
Chromosomal abnormalities
Excess chemical intake (Tetracycline, Fluoride)

Natal
Birth injury
Premature delivery
Prolonged labor

Postnatal
Severe childhood infections
Congenital heart diseases
Nutritional deficiencies (Vit-B, Vit-D)
Endocrinal disorders

181. Enamel hypoplasia due to nutritional deficiency
and exanthematous fevers
Serious nutritional deficiency is potentially capable of
producing enamel hypoplasia
The teeth that form within the first year after birth are
affected.
Teeth most frequently affected are central & lateral
incisors, cuspids and first molars.
Premolars, 2
nd
& 3
rd
molars are rarely affected, since
their formation does not begin until the age of 3 or later
Presents as pitting of the tooth surface

182. Enamel hypoplasia due to congenital syphilis
Hypoplasia is not of pitted variety
Involves the permanent maxillary & mandibular incisors
and 1
st
molars
Anterior teeth are referred to as hutchinson‟s incisors
and posterior teeth are referred to as mulberry molars.
Characteristically, the upper central is screw driver
shaped, the mesial and distal surfaces tapering and
converging towards the incisal edge.
Incisal edge is usually notched.
Middle lobe of tooth is affected

183. The crowns of first molars are irregular & constricted,
and the enamel of the occlusal surface and occlusal
third of tooth appears to be arranged in an agglomerate
mass of globules rather that well formed cusps.
Resembles a mulberry, hence the name mulberry
molars

184. Enamel hypoplasia due to fluoride
Excess amounts of fluoride can result in enamel defect
known as dental fluorosis./ mottled enamel
First described by GV Black & Federick S McKay in
1916
The severity increases with an increase in amount of
fluoride in the water.
The optimum range of fluoride in drinking water is 0.7 -
1.2 ppm

185. Pathogenesis
Increased levels of fluoride interferes with calcification
process of the enamel matrix leading to the formation of
hypomineralized enamel

These alterations results in an increased surface and
subsurface porosity of the enamel which alters the light
reflection and creates the appearance of white chalky
areas which later gets stained

186. Clinical features
Affected teeth are caries resistant
Wide range of manifestations depending on fluoride levels
Grading
–Questionable changes
•White flecking or spotting of enamel
–Mild changes
•White opaque areas involving more of tooth surface areas
–Moderate and severe changes
•Pitting and brownish staining of surface
–Corroded appearance

187. Mild cases- Bleaching of teeth
Severe cases- Prosthetic crowns
Treatment

188. Dentinogenesis Imperfecta
A hereditary defect of dentin in the absence of any
systemic disorder, consisting of opalescent teeth,
composed of irregularly formed and undermineralized
dentin that obliterates the coronal and root portion of
pulp chamber.

Autosomal dominant mode of transmission

Also known as “Hereditary opalescent dentin” &
“Capdepont’s teeth”

189. Classification
Clinical presentation By
Shields
By Witkop
Osteogenesis imperfecta
with opalescent teeth
DI - I Dentinogenesis
imperfecta
Isolated opalescent teeth DI - II

Hereditary
opalescent teeth
Isolated opalescent teeth DI - III

Brandywine type

190. Type I
Associated with osteogenesis imperfecta
Type II
Not associated with osteogenesis imperfecta unless
by chance
This type is most frequently referred to as Hereditary
opalescent dentin
 Most common type
Type III
Brandywine type, racial isolate in Maryland state
Same clinical presentation of Type I or II with
multiple pulpal exposures in deciduous dentition
Clinical features

191. Severely affects the deciduous teeth than permanent
teeth (Incisors & 1
st
molars; Least involved teeth- 2
nd
&
3
rd
molars)
Teeth exhibits a gray to brownish violet or yellowish
brown appearance
Involved teeth exhibits a characteristic unusual
translucent or opalescent hue.
Enamel is normal but fractures and chips away easily,
leads to exposed dentin and functional attrition
presumably because of defective DEJ
Teeth are not particularly sensitive & are not caries
prone

192. Type I
–Deciduous teeth more severely affected.
Type II
–Both dentition affected
Type III
–Both dentition affected
–Multiple pulpal exposures in deciduous dentition

194. Radiological features
Radiologically type I & II are similar

Exhibit bulb-shaped or bell shaped crowns with
constricted CEJ

Thin & blunted roots

Early obliteration of root canals and pulp chamber

Cementum, PDL & bone appears normal

195. Type III exhibits great variability in deciduous teeth,
ranging from normal to those changes of type I & II.

Shell teeth
–Apparently normal enamel
–Extremely thin dentin (may involve entire tooth or
isolated to the root)
–Enormous pulp chambers (not as a result of resorption,
but due to insufficient dentin)
–Appear as shells of enamel & dentin surrounding
enormous pulp chambers and root canals.

197. Shell teeth

198. Histopathological features
Enamel & mantle dentin are normal

Remaining dentin is severely dysplastic & exhibits vast areas of
inter-globular dentin

Dentinal tubules are short, disoriented, irregular & widely spaced

Scanty odontoblasts line the pulp and they can be seen in the
defective dentin

The DEJ is Smooth

200. Treatment
Treatment is aimed at preventing excessive tooth
attrition & improving esthetics

Metal / Ceramic crowns & over dentures can be given

201. Dentin dysplasia
A hereditary defect characterized by defective dentin
formation & abnormal pulpal morphology

Autosomal dominant disorder

202. Types
Type I – Radicular dentin dysplasia
–Also known as “Rootless teeth”

Type II – Coronal dentin dysplasia


Mild Severe

203. Clinical features
Type I Type II
Disturbance in development of
radicular dentin
Disturbance in development of coronal
dentin
Normal crowns, both structurally &
morphologically

Semi-transparent opalescent 1
0
teeth
Normal appearance in the permanent teeth
Color of teeth normal with
slight bluish translucency in
cervical region
Amber – grey color
Early loss of dentin organization
results in extremely short roots
Later disorganization results in
minimal root changes
Affected teeth exhibits short roots,
delayed eruption , severe mobility &
premature exfoliation

205. Radiological features
Type I Type II
Deciduous teeth affected severely with
little or no detectable pulp
Deciduous teeth shows bulbous
crowns, cervical constriction and early
obliteration of pulp (Resembles DI)
Permanent teeth: Features vary on the
proportion of organized versus
disorganized dentin
Early disorganization - extremely short
roots with little or no pulp
Somewhat Later disorganization -
crescent or chevron shaped pulp
chambers overlying shortened roots
that exhibit no pulp canals
Late disorganization – normal pulp
chamber with large pulp stone
Permanent teeth: Exhibits abnormally
large pulp chambers and apical
extension described as flame shaped
or thistle-tube in shape. Pulp stones
present

Periapical radiolucencies around the
defective roots
Absence of periapical radiolucencies

207. Histopathological features
Type I Type II
Normal enamel

Normal enamel and radicular dentin with
partial obliteration of root canals
Portion of coronal dentin is usually
normal and may show tubular dentin
apical to it
Pulp is obliterated by calcified tubular
dentin, osteodentin & fused denticles
Near normal coronal dentin with
numerous areas of interglobular dentin
near the pulp

Normal dentinal tubule formation
appears to be blocked so that new
dentin forms around obstacles and takes
on characteristic appearance described
as lava / stream flowing around boulders
Abnormally large pulp chambers with
pulp stones

209. Treatment
No treatment
Prognosis depends on presence / absence of periapical
lesions

210. Regional odontodysplasia
It is an uncommon non-hereditary developmental
disturbances of tooth characterized by defective
formation of enamel & dentin with abnormal
calcifications of pulp

Also known as Ghost teeth / odontogenesis
imperfecta

Cause
–somatic mutation
–Slow virus residing in odontogenic epithelium
–Local ischemic change during odontogenesis

211. Clinical features
More common in permanent dentition
More common in maxilla
Affects several teeth in a single quadrant
Maxillary anterior teeth affected more
Failure of eruption or delayed eruption of affected teeth
Teeth are deformed, yellowish – brown in color with a
soft leathery surface

212. Radiological features
Marked decrease in radiodensity of teeth
Enamel & dentin are very thin & radiological distinction
not possible
Extremely large & open pulp chamber with pulp stones
Ghostly appearance of affected teeth

214. Histopathological features
Abnormal enamel & dentin
Marked reduction in amount of dentin, widening of
predentin layer, large areas of interglobular dentin and
an irregular pattern of dentin
Large pulp chamber with pulp stones
Calcification in follicular connective

215. Treatment
Extraction & artificial prosthesis

216. Developmental Anomalies affecting
the jaws

217. Agnathia
Micrognathia
Macrognathia
Facial hemihypertrophy
Facial hemiatrophy

218. Agnathia
Congenital absence of maxilla or mandible
Commonly, only a portion of one jaw is missing
–In maxilla
•Maxillary process
•Premaxilla
–In mandible
•Entire mandible
•Condyle
•Entire ramus

219. Micrognathia
A smaller jaw than normal
Involve either maxilla or mandible

Types
Apparent [Abnormal positioning/ relation of one jaw to the other or skull]
True
Congenital
Acquired

220. Congenital micrognathia
Etiology unknown
Associated with other congenital abnormalities like
congenital heart disease and pierre robin syndrome
Micrognathia of maxilla is due to a deficiency of the
premaxillary area
Micrognathia of mandible may be due to
–Small jaw
–Posterior positioning of mandible in relation to skull
–Steep mandibular angle
–Agenesis of condyles

221. Acquired micrognathia
Post natal in origin

Causes
–Ankylosis of joint as result of trauma/infection

222. Macrognathia
Condition of abnormally large jaws
Seen in
–Pagets disease of bone
–Enlarged maxilla
–Acromegaly
–Enlarged mandible
–Leontiasis ossea
–Enlarged maxilla