This document discusses various types of developmental anomalies that can affect oral and paraoral structures. It begins by defining developmental anomalies as defects resulting from disturbances in growth and development. It then categorizes anomalies based on their origin, such as congenital, hereditary, familial, acquired, hamartomatous, or idiopathic. The document further discusses specific anomalies affecting the teeth, jaws, and oral soft tissues. It provides examples and classifications for anomalies like microdontia, macrodontia, anodontia, supernumerary teeth, and others. Syndromes that are associated with certain oral anomalies are also mentioned.

1. Developmental Anomalies Of
Oral & Para-oral Structures
Dr. Vardendra M
Reader
Dept of Oral Pathology
NDC, Raichur

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 3rd 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 3rd molars, maxillary & mandibular 1st
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
- Atavism

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 3rd 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 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

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
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 2nd & 3rd 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. 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

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

111. Mild moderate severe
Normal

113. Syndromes associated
Klinefelter’s syndrome
Down syndrome
Poly X syndrome
Ectodermal dysplasia

114. 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

116. 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

118. 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

119. Enamel extensions lead to loss of PDL attachment and
may predispose to development of:
1. Periodontal pocket
2. Buccal bifurcation cyst
Clinical significance

120. Disturbance in position
Ectopia
Trans position
Trans migration
Rotation

121. 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 3rd molar erupting at angle of mandible /
lower border of mandible / through the skin of cheek

123. 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

125. Rotation
Developmental anomaly where in a tooth turns
partially / completely
Commonly seen in,
Maxillary 2nd premolar (Complete rotation)
Maxillary central & 1st premolar (Partial rotation)

127. 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

128. Delayed eruption
Tooth erupts into oral cavity
much later than normal time of
eruption
Affects both deciduous &
permanent dentition

129. Premature eruption
Tooth erupts into oral cavity
much earlier than normal time
of eruption
Frequently involved tooth are
deciduous mandibular central
incisors

130. Types
Natal teeth
Erupted deciduous teeth present at the time of birth
Neonatal teeth
Deciduous teeth which erupt within first 30 days of life

131. Causes
Endocrinal disturbances
- Adreno-cortical syndrome
- Hyperthyroidism
Premature loss of deciduous teeth causes premature
eruption of permanent teeth

132. Systemic factors
- Rickets
- Cleidocranial dysplasia
- Cretinism
Local factors
- Fibromatosis gingivae
- Cleft lip & palate
- Retained deciduous tooth
Idiopathic
Causes

133. 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

134. 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

135. Mesioangular : Impacted tooth mesially inclined
Distoangular : Impacted tooth distally inclined
Vertical : Impacted tooth lies vertical
Horizontal : Impacted tooth lies horizontal

137. Complications
Crowding
Malocclusion
Pericoronitis
Radiating pain
Root resorption of adjacent erupted teeth
Caries
Food impaction & halitosis
Dentigerous cyst
Treatment:-
- Removal of cause
- Surgical removal

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

139. 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

141. Disturbance in structure of teeth

142. 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

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

144. 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

145. Hereditary enamel hypoplasia

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

147. 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)

148. 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

149. 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

150. 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

151. TYPE IV Hypomaturation-hypoplastic with
taurodontism
IVA - Hypomaturation-hypoplastic with
taurodontism, Autosomal Dominant
IVB - Hypoplastic-Hypomaturation with
taurodontism, Autosomal Dominant

152. Clinical features

153. 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

155. 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

157. 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

158. Treatment
No definitive treatment
Veneering or capping of teeth to improve esthetics

159. Environmental enamel hypoplasia

160. 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

161. 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

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

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

164. 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

165. 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”

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

168. 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

169. 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.

171. Shell teeth

172. 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

174. Treatment
Treatment is aimed at preventing excessive tooth
attrition & improving esthetics
Metal / Ceramic crowns & over dentures can be given

175. Dentin dysplasia
A hereditary defect characterized by defective dentin
formation & abnormal pulpal morphology
Autosomal dominant disorder

176. Types
Type I – Radicular dentin dysplasia
– Also known as “Rootless teeth”
Type II – Coronal dentin dysplasia
Mild
Severe

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

179. Regional odontodysplasia
It is an uncommon non-hereditary developmental
disturbances of tooth characterized by defective
formation of enamel & dentin with abnormal
calcifications of pulp & follicle
Also known as Ghost teeth / odontogenesis
imperfecta
Cause
– somatic mutation
– Slow virus residing in odontogenic epithelium
– Local ischemic change during odontogenesis

180. 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

181. 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

183. 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

184. Treatment
Extraction & artificial prosthesis

185. Developmental Anomalies affecting
the jaws

186. Agnathia
Micrognathia
Macrognathia
Facial hemihypertrophy
Facial hemiatrophy

187. 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

188. 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

189. 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

190. Acquired micrognathia
Post natal in origin
Causes
– Ankylosis of joint as result of trauma/infection

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