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Abnormalities of Teeth Structures
1. Abnormalities of Teeth
Dr. Arsalan Malik
Assistant Professor & HOD (Oral Pathology)
ِيم ِحَّالر ِمنْحَّالر ِهللا ِمْسِب
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2. Environmental Alterations of Teeth
Developmental tooth defects
Post developmental structural tooth loss
Discoloration of teeth
Localized disturbances in eruption
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5. Enamel Defects
Enamel Hypoplasia
Occurs in form of pits, grooves or larger areas of missing enamel
Diffuse Opacities
Variation in the translucency of enamel. Normal thickness with white opacities and no boundary
Demarcated Opacities
Variation in the translucency of enamel. Normal thickness with white opacities and clear boundary
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6. Turner’s Hypoplasia
It is caused by periapical inflammatory
disease of the overlying deciduous tooth.
Most commonly noted in permanent bicuspids
due to overlying deciduous molars
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7. Turner’s Hypoplasia
Degree of damage depends upon stage of development, length of time of infection,
virulence of organism and the host resistance factors
If the primary tooth develops caries, the successor is twice likely to develop caries
If the primary tooth is extracted for some reason other than trauma, prevalence of
demarcated enamel is increased 5 folds.
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8. Molar Incisor Hypomineralization
o Enamel defects of one or more first permanent molars
o The altered enamel is white, yellow or brown and often
soft and porous.
o Affected teeth are sensitive to cold and warmth and
enamel chip off easily
o Difficult to anesthetize during dental procedures
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9. Dental Fluorosis
The integration of excess amount of fluoride can also
result in enamel defects known as dental fluorosis
The integration of fluoride into the enamel reduces the
incidence of caries
Pre-eruptive as well as post eruptive supply of fluoride is
equally effective however the 2nd & 3rd decade is critical for
application of fluoride
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10. Dental Fluorosis
A definitive diagnosis requires bilateral presence
of defects, evidence of prior fluoride intake and
elevated levels of fluoride in enamel
The antibiotic administration during development
reduces the expression of enamel proteins genes
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12. Attrition
Loss of tooth structure caused by tooth to tooth
contact during occlusion and mastication
Main factors are
◦ Poor quality or absent enamel
◦ Premature contacts
◦ Intra oral abrasive, erosions and grinding habits
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13. Abrasion
Pathological loss of tooth structure or restoration secondary to the
mechanical action of an external agent
Common causes are
◦ Hard tooth brush with abrasive tooth paste
◦ Chewing tobacco, biting nails or pencil
When tooth wear is accelerated by chewing an abrasive
substance, the process is termed as Demastication and it
exhibits features of abrasion and attrition
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14. Erosion
o Loss of tooth structure caused by non bacterial chemical
process. The gradual destruction of surface by the chemical
or electrolytic process
o Erosion from dental exposure to gastric secretion is termed
as Primolysis
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15. Abfraction
o It appears as wedge shaped defects limited to
the cervical area of the teeth and may closely
resemble cervical abrasion or erosion
o Clues to the diagnosis are deep, narrow and
v shaped defects that predominantly affects
facial surfaces of bicuspids and molars
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16. Resorption
Destruction of tooth can also occur through resorption, which is accomplished by cells
located in the pulp (Internal resorption) or in the periodontal ligament (External
resorption)
Internal resorption is a relatively rare occurrence and mostly it develops after trauma to
the pulpal tissues of the tooth
It continues as long as vital pulp tissue remains and may result in communication of
pulp with the PDL.
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17. Factors Associated with External Resorption
Cysts
Dental trauma
Excessive mechanical forces
Excess occlusal forces
Hormonal imbalance
Peget’s disease of bone
Periodontal treatment
Tumours
Reimplantation of teeth
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18. Clinical Features
Inflammatory resorption
The resorbed dentin is replaced by inflamed granulation tissues. Most commonly cervical portion is
involved and resorption continues as long
Replacement resorption
Portion of the dentinal walls are resorbed and replaced with bone or cementum like material.
Radiographically it appears as enlargement of the pulp canal and filled with a material that is less
radiodense as compared to surrounding zone.
After re-implantation of tooth, extensive resorption starts without rapid intervention
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20. Histopathological Features
Pulp tissues are vascular and exhibit increased cellularity.
Numerous multinucleated dentinoclasts are present adjacent to
the dentinal walls.
Inflammatory infiltrate is present
In replacement resorption, the normal pulp tissues are replaced
by woven bone that is fused to adjacent dentine.
Areas of resorption are often repaired by deposition of
osteodentine
Extensive bone deposition in external resorption may lead to
ankylosis
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24. Localized Disturbances in Eruption
Impaction
Teeth that cease to erupt before emergence are called Impacted
Ankylosis
Eruption continues after emergence of teeth to compensate for masticatory wear and the growth of
jaws. The cessation of eruption after emergence is termed Ankylosis
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25. Impaction
In permanent dentition, the most frequently impacted tooth is
mandibular 3rd molar followed by maxillary 3rd molar and cuspids
Factors associated with impaction are
Overlying cysts or tumours
Trauma
Reconstructive surgery
Thickened overlying bone
Systemic disorders
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26. Ankylosis
Associated factors
Disturbances from changes in local metabolism
Trauma
Injury
Irritation
Local failure of bone growth
Abnormal pressure from the tongue
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27. Developmental Alterations of Teeth
Number
Hypodontia
Hyperdontia
Size
Microdontia
Macrodontia
Shape
Gemination
Fusion
Concresence
Taurodontism
Hypercementosis
Dilaceration
Dens invaginatus
Dens Evaginatus
Structure
Amelogenisis Imperfecta
Dentinogenisis Imperfecta
Dentin Dysplasia type I
Dentin Dysplasia type II
Regional Odontodysplasia
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28. Hypodontia
Lack of development of one or more
teeth is referred as Hypodontia
Total lack of tooth development is
called Anodontia
Lack of development of 6 or more
teeth is called Oligodontia
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29. Hyperdontia
Development of increased number of teeth
is referred as Hyperdontia
The additional teeth are referred to as
Supernumerary teeth.
The Supernumerary teeth in the midline is
called Mesiodense
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32. Microdontia
When the teeth are physically smaller
than normal then it is termed as
Microdontia
Normal size teeth may appear smaller
when they are widely spaced within large
size jaws. This is termed as Relative
Microdontia but it is actually
macrognathia
Maxillary lateral incisors are most
commonly effected and appear as peg
shaped crown.
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33. Macrodontia
When the teeth are physically larger
than normal then it is termed as
Macrodontia
Normal size teeth may appear larger
when they are crowded within small
size jaws. This is termed as Relative
Macrodontia but it is actually
micrognathia
Diffuse macrodontia has been
observed in pituitary gigantism and
otodental syndrome
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34. Gemination
It is defined as an attempt of a single
tooth bud to divide with the resultant
formation of a tooth with bifid crown and
usually a common root and root canal.
The tooth count remains normal when
the anomalous tooth is considered as
one.
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35. Fusion
It is considered to be the union of two
normally separated teeth buds with the
resultant formation of a joined tooth with
confluence of dentin.
In this condition the tooth count shows one
missing tooth when the tooth count is
considered as one.
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36. Concrescence
It is described as two fully formed teeth
joined along the root surfaces by cementum.
More commonly present in posterior &
maxillary teeth.
The development pattern often involves
second molar tooth where roots are in close
proximity to 3rd molar tooth.
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37. Dens Evaginatus
It is a cusp like elevation of enamel located in the central groove or lingual ridge of the buccal
cusp of premolar or molar tooth.
The accessory cusp usually consist of enamel & dentine with pulp present in half of the cases
The accessory cusp creates occlusal interference that are associated with clinical problems.
Pulp necrosis is common and may occur through a direct exposure or invasion of patent,
immature dentinal tubules.
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39. Dens Invaginatus
Deep surface invagination of the crown or root that is lined by enamel.
The depth of invagination varies from a slight enlargement of the cingulum pit to a deep
infolding that extends to apex.
Occasionally the invagination may be large and resemble a tooth within tooth appearance
called den in dente.
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41. Taurodontism
Enlargement of the body & pulp chamber of a
multirooted tooth with apical displacement of the pulpal
floor & bifurcation of the root.
It may be unilateral or bilateral affecting permanent
dentition.
Classified into mild, moderate and sever forms
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42. Hypercementosis
Non neoplastic deposition of excessive
cementum that is continuous with the normal
radicular cementum.
Radiographically affected tooth show thinking or
blunting of root but the exact amount of extra
cementum is difficult to estimate
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44. Dilaceration
Abnormal angulation or bend in the root or less
frequently in the crown
A number of teeth having dilacerations arises
after injury that displaces the calcified portion of the
tooth germ and remainder of the tooth is formed at
an abnormal angle
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45. Supernumerary Roots
It refers to the development of an increased
number of roots on a tooth compared with that
classically described in dental anatomy.
Most commonly affected teeth are permanent
molars from either arch and mandibular cuspids
and premolars
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46. Amelogenisis Imperfecta
A complicated group of conditions that demonstrate
developmental alterations in the structure of enamel in
the absence of any systemic disease.
Different classification systems were proposed but
Witkop’s Classification is widely accepted.
It is based on phenotype and pedigree (clinical
appearance & apparent mode of inheritance)
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47. Amelogenisis Imperfecta
Formation of enamel is a multistep process and
problem may arise in any of these them.
1) Elaboration of the organic matrix
2) Mineralization of the matrix
3) Maturation of the enamel.
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48. Hypoplastic Amelogenisis Imperfecta
o The basic alteration centres on inadequate deposition of
enamel matrix.
o The matrix present is well mineralized and
Radiographically contrasts well with the underlying dentine
o In generalized pattern pinpoint to pin head pits are
scattered on the surface.
o Staining of the pits may occur.
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49. Hypoplastic Amelogenisis Imperfecta
o In localized pattern, the affected teeth demonstrate horizontal rows of pits, linear
depression or one large area of hypocalcification.
o In other patterns of this disorder, enamel may appear smooth, thin, hard and glossy.
o Radiographically demonstrate a thin radio-opaque line of enamel.
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50. Hypomaturation Amelogenisis Imperfecta
• Enamel matrix is laid down properly and begin to mineralize but there is defect in
maturation of enamel crystal structure
• Affected teeth are normal in shape but show mottled appearance and tend to chip easily
• Radiographically its density is similar to dentine
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52. Hypocalcified Amelogenisis Imperfecta
o Enamel matrix is laid down properly but failed to mineralize properly
o Affected teeth are proper in shape but very soft & easily lost
o It has more tendency of calculus deposition on it
o Radiographically the density of enamel & dentine is similar
o After some duration time of eruption, cuspal enamel is lost leaving occlusal surfaces
irregular
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54. Histopathological Features
These are not evident in routine preparations because decalcification of the teeth is
necessary before processing and all the enamel is lost in it
Ground sections of Non decalcified teeth are prepared for examination
The alterations are highly diverse and depend upon the type of variation in enamel structure
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55. Treatment
o Main problems are aesthetics, dental sensitivity and loss of vertical dimension
o In some types, increased prevalence of caries, anterior open bite, delayed eruption and associated
gingival enlargement are observed
o Crown placement
o Full dentures
o Veneers
oGlass Ionomer Cements restorations
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56. Dentinogenesis Imperfecta
o It is a hereditary developmental disorder of the dentine in the absence of any systemic
disease.
o It is associated with mutation in DSPP gene.
Shields Clinical Presentation
Dentinogenesis Imperfecta I Osteogenesis imperfect with opalescent dentine
Dentinogenesis Imperfecta II Isolated opalescent teeth
Dentinogenesis Imperfecta III Isolated opalescent teeth
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58. Clinical Features
o All teeth in both dentitions are affected
o The severity of problem depends upon the
age at which teeth developed
o Deciduous teeth are affected more
intensely followed by permanent incisors
and 1st molars
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59. Clinical Features
o Blue to brown discoloration often with
distinctive translucence
o Enamel easily gets separated form
underlying dentine leading to rapid attrition
oUsually the pulp is obliterated by excessive
dentine formation but sometimes shell teeth
are observed having small dentine and large
pulp chambers.
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60. Radiographic Features
o Teeth have bulbous crowns, cervical
constrictions, thin roots and early
obliteration of the root canals and pulp
chambers.
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61. Histopathological Features
o Dentine adjacent to enamel are similar to
normal dentine but the remainder is
significantly different
o Scanty atypical odontoblasts line the pulp
surface and cells can be seen entrapped
within defective dentine
o1/3rd of the patients have hypoplastic
enamel
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62. Treatment
o Teeth are not good candidates for crown placement because of cervical fractures
o Overly dentures placed on teeth with fluoride releasing material is being practiced in
some cases
o In cases with lose of vertical dimension, metal crowns are used with adhesive bonding
agents
o On occlusal surfaces composites are being used
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