Transcript disorders of development of teeth

DISORDERS OF
DEVELOPMENT OF
TEETH
May be prenatal or postnatal in origin
 May be inherited or acquired
Causes :
 Abnormalities in the differentiation of the dental
lamina and the tooth germs leading to
anomalies in the number, the size and shape of
teeth (abnormalities of morphodifferentiation)
 Abnormalities in the formation of the dental hard
tissues leading to disturbances in tooth structure
(abnormalities of histodifferention).

DISTURBANCES IN NUMBER
OF TEETH.
ANODONTIA= Absence of teeth
 May be :
– Complete anodontia
– Partial anodontia (hypodontia)
– Pseudoanodontia : Absent teeth because of
impaction or delayed eruption
– False anodontia : When teeth have been
exfoliated or extracted
NUMBER (cont…)
Partial anodontia is relatively common,
mostly third molars, followed by second
premolars and maxillary lateral incisors.
 Complete anodontia is rare but is often
associated with hereditary ectodermal
dysplasia (hypohidrotic ectodermal
dysplasia).

NUMBER (cont…)
SUPERNUMERARY TEETH.

May have a normal morphology : Supplementary teeth

May be rudimentary and miniature
Causes:

Hereditary

Syndrome associated (cleft palate or cleidocranial
dysplasia)
Location:

Most frequently in the anterior and molar regions of
the maxilla, followed by the premolar region of the
mandible

Permanent dentition more affected than primary ;
females more affected than males.
SUPERNUMERARY
TEETH(cont…).
Significance:
 Supernumerary teeth occupy space, may prevent the
eruption of other teeth.
 May erupt into the buccal or lingual embrasure or
outside the line of the dental arch
 May cause delayed eruption, maleruption and
malalignment of other teeth
 Inaesthetic
 If between the roots of adjacent teeth, they cause
diastema
 Resorption of adjacent teeth
 May develop into dentigerous cysts if unerupted
SUPERNUMERARY
TEETH(cont…).
Mesiodens:
 These are supernumerary teeth occurring between
central incisors
 Most common of all the supernumerary teeth
 They mostly occur between the maxillary central incisors
Natal teeth:
 Supernumerary teeth appearing at the time of birth
 Very rare
 Not to be confused with prematurely erupted deciduous
teeth and eruption cysts or false teeth
 Usually mandibular central incisors
DISTURBANCES IN SIZE OF
TEETH
MICRODONTIA.
May be

Generalized or localized

True microdontia when teeth are measurably smaller
than normal (in pituitary dwarfism)

Relative microdontia in comparison with a large
mandible and maxilla

Usually the shape is also altered

Commonly seen with the maxillary lateral incisors=
peg shaped laterals, followed by maxillary 3rd molars
and supernumerary teeth
Causes: Usually hereditary in origin
Significance: Only cosmetic
SIZE (cont…)
MACRODONTIA.
May be generalized:

Absolute macrodontia as seen in pituitary gigantism

Relative macrodontia when seen on a disproportionately small
maxilla and mandible
May also be localized:

Abnormally large tooth or group of teeth

Relatively uncommon condition

Usually seen with mandibular 3rd molars, incisor and canine
region.
Hemifacial hypertrophy:

The teeth on the affected side are abnormally large compared
with the unaffected side
DISTURBANCES IN SHAPE OF
TEETH.
May involve the crown, the root or both
GEMINATION.
Definition:
 This is a fusion of two teeth from a single enamel organ resulting
either in:
 Partial cleavage leading to two crowns that share the same root and
same pulp canal
 Complete cleavage making twinning (2 teeth from one tooth germ)
The cause is unknown but trauma has been suggested
as a possible cause
Significance:
- Inaesthetic
- May cause crowding of teeth
SHAPE (cont…)
FUSION.
Definition:

It is the joining of two developing tooth germs, resulting in a
single large tooth.

The fusion process may involve the entire length of the tooth or
the roots only; in that case, cementum and dentin are shared.
Root canals may also be separate or shared. May also involve the
crown only.

The fusion must involve the dentin because, when 2 teeth are
connected only by cementum, the condition is termed
“concrescence”

It may be impossible to differentiate fusion of normal or
supernumerary teeth from germination.

The cause is unknown but trauma has been suggested
SHAPE (cont…)
CONCRESCENCE.
Definition:

It is a form of fusion in which the adjacent, already formed teeth
are joined by cementum. It is an acquired anomaly

This may take place before or after eruption of teeth

Most commonly seen in association with the maxillary second and
third molars
Causes:

Believed to be related to trauma or overcrowding

Most frequently seen in the permanent dentition where the roots
develop close together

Hypercementosis associated with chronic inflammation
Significance:

None unless one of the teeth involved requires extraction.
Surgical sectioning may be required to save the other tooth.
SHAPE (cont…)
DILACERATION.
Definition:

It is an extraordinary curving or angulation of tooth
roots.
Causes:

Trauma during root development

Hereditary factors

Lack of space for development
Significance:

Eruption generally continues without problems

Extraction may be difficult

Root canal treatment may be challenging
SHAPE (cont…)
DENS INVAGINATUS.
Definition:
Also known as dens in dente, it is an uncommon tooth anomaly
that represents an exaggeration or accentuation of the lingual pit.
Can range from superficial (only the crown affected) to deep
(crown and root involved).

Permanent maxillary lateral incisors most commonly involved

Any anterior tooth may be affected

Bilateral involvement commonly seen
Cause:

Unknown

Genetic factors believed to be involved in small percentages of
cases
SHAPE (cont…)
Complications:
 Predisposes the tooth to early decay and
subsequent pulpitis
Management:
 Prophylactic filling of the pit is recommended to
avoid these complications
 When pulpitis has led to nonvitality, endodontic
procedures may salvage the affected tooth
SHAPE (cont…)
DENS EVAGINATUS.
Definition:
This is a relatively common developmental condition
characterized by an anomalous tubercle, or cusp, often
bilateral, located in the center of the occlusal surface.
The premolar teeth are predominantly affected.
Causes:

It is unknown but race related because it has been
reported almost exclusively in Asians and Native
Americans.
SHAPE (cont…)
Complications:
 There can be an early exposure of an accessory pulp
horn extending into the tubercle due to quick occlusal
abrasion.
 Periapical pathology in young caries-free teeth often
before completion of root development and apical
closure making root canal fillings challenging
Management:
 Grinding the opposing tooth or the tubercle to stimulate
secondary dentin formation in order to prevent the
periapical syndrome.
SHAPE (cont…)
TAURODONTISM.
Definition:
A taurodont tooth(bull-like tooth) is one in which the pulp chamber has
a greater apico-occlusal height than in normal teeth, whith no
constriction at the level of the amelo-cemental junction; the chamber
extends apically well beyond the cervix.
It affects multirooted teeth and is rare in primary dentition
Causes:

Failure of Hertwig’s sheath to invaginate at the proper horizontal level

Can be seen as an isolated incident or in association with syndromes
such as Down’s syndrome and Klinefelter’s syndrome.

Genetic factors (high prevalence in Eskimos and Middle Eastern
population)
Significance:

Little clinical significance, no treatment required

Aesthetic concern
SHAPE (cont…)
SUPERNUMERARY ROOTS.
Definition:
These are accessory roots commonly seen in
mandibular canines, premolars and molars. They are
rarely seen in upper anterior teeth and mandibular
incisors
Significance:
When extractions or root canal fillings are necessary,
radiographic recognition of an extraordinary number of
roots becomes important.
SHAPE (cont…)
ENAMEL PEARLS.
Definition:

These are small masses of enamel found apically to the
amelocemental junction.

They occur most commonly in the bifurcation or trifurcation of
teeth but may appear on single-rooted premolar as well.

Maxillary molars more commonly affected than mandibular

Can be detected radigraphically
Cause:

Hertwig’s sheath remains in contact with the dentin and
stimulated to differentiate into functional ameloblasts.
Significance:

Little clinical significance except when located in an area of
periodontal disease.
DISTURBANCES IN
STRUCTURE OF TEETH.
DISTURBANCES IN STRUCTURE OF ENAMEL.

Enamel normally develops in two stages:
Secretory stage:

Matrix production

Initial mineralization
Matrix production: Synthesis and secretion of
matrix proteins (amelogenins and enamelins)
Initial mineralization: Appears immediately after
secretion, crystals abut the plasma
ENAMEL DEFECTS (cont…)
Maturation stage:


Withdrawal of water and proteins
Concomittant increase in mineral content before the tooth erupts
Defective amelogenesis can be related either to matrix formation leading to
enamel hypoplasia or to mineralization and maturation stages leading to
hypomineralized enamel.
Enamel Hypoplasia:

It is a quantitatively defective enalel, when of normal hardness
Enamel hypocalcification:

It is a qualitatively defective enamel when normal amounts of enamel is
produced but are hypomineralized; the enamel is softer than normal.
ENAMEL DEFECTS (cont…)
The extent of enamel defects depends on three
conditions:
 The intensity of the etiologic factor
 The duration of the factor’s presence
 The time at which the factor occurs during
crown development.
Clinical features:
 Defects can range from yellowish or brownish
pigmentation of the enamel to extensive pits
and irregularities of the surface
 The crown is usually smaller than normal.
ENAMEL DEFECTS (cont…)
Localized causes:
 Local infections or trauma related to the
deciduous predecessor resulting in
damage to the ameloblasts of permanent
successor.Such teeth are often called
Turner teeth.
 Radiotherapy
 Idiopathic
ENAMEL DEFECTS (cont…)
General causes:
 Environmental/Systemic factors: Can be either
Prenatal:- Infections, e.g. rubella, syphilis
 Maternal disease
 Excess fluoride ions
Neonatal: -Haemolytic disease of the newborn
 Hypocalcaemia
 Premature birth/ Prolonged labour
ENAMEL DEFECTS (cont…)
Postnatal:
 Severe childhood infections especially the
viral exanthema
 Chronic diseases in childhood e.g.
congenital heart disease, gastrointestinal
and endocrine diseases
 Nutritional deficiencies e.g. vit D
 Cancer chemotherapy
 Excess fluoride ions
ENAMEL DEFECTS (cont…)
For systemic factors to have an effect on the
developing permanent teeth, they must
generally occur after birth and before the age of
6 years.
Genetic factors:
 Only teeth affected- Amelogenesis imperfecta
 Teeth affected in association with generalized
defects- Ectodermal dysplasia syndromes
 Down’s syndrome (Trisomy 21)

ENAMEL DEFECTS (cont…)
ENAMEL OPACITIES.
Definition:
These are white spots seen in smooth surface enamel, some of which
become brown-stained after eruption.
They are most common in children aged 12-14years
Both deciduous and permanent dentitions are affected.
 Maxillary permanent central incisors most frequently involved


Causes:
 Unknown but are thought to be due to local rather than systemic factors
 The prevalence is less in areas with 1 PPM of fluoride in the drinking water
 The opaque spots are hypomineralized.
ENAMEL DEFECTS (cont…)


CHRONOLOGICAL HYPOPLASIAS.
Most enamel hypoplasias due to environmental
causes are of this type. They are time related
disturbances. E.g. Any serious nutritional deficiency
or systemic disease occurring during the time of
formation of teeth.
 The disturbance occurring in utero, at or soon after
birth may affect the incisal edges of the permanent
central incisors and the occlusal surfaces of the first
permanent molars, in addition to the deciduous teeth.
ENAMEL DEFECTS (cont…)
CONGENITAL SYPHILIS.
 Affects permanent incisors and first molars
 Affected incisors (Hutchinson’s incisors)
are tapered incisally and notched centrally
on the incisal edge
 Affected molars (Mulberry molars) show a
lobulated occlusal surface.
ENAMEL DEFECTS (cont…)
FLUORIDE IONS.
 Ingestion of drinking water containing fluoride at levels
greater than 1 PPM during the time the crowns are being
formed may result in enamel hypoplasia or
hypocalcification= Fluorosis.
Clinical features:
Mild to moderate fluorosis:
 Ranges from white enamel spots to mottled brown-andwhite discolorations
Severe fluorosis:
 Pitted, irregular, discolored enamel
 Are cosmetically objectionable.
ENAMEL DEFECTS (cont…)
AMELOGENESIS IMPERFECTA.
Definition:
 It is an inherited developmental abnormality of enamel.
Affects both dentitions.
Classification: 2 main types
 Hypoplastic: Defective matrix formation
 Hypocalcified: Matrix formation isnormal but calcification
is abnormal
Causes: Genetic factors
 Autosomal dominant
 Autosomal recessive
 X-linked patterns
ENAMEL DEFECTS (cont…)
Clinical manifestations:
The defects range from pits and grooves in one patient
to complete absence (aplasia) in another
 Abnormal contour and absent interproximal contact
points may be evident
 Fractures and wears due to gross attrition appear readily
in the hypocalcified type, exposing the dentine
 Sometimes, in the smooth form, teeth have sharp,
needle-like cusps
 Color varies from white opaque to yellow to brown

ENAMEL DEFECTS (cont…)
Teeth tend to darken with age due to exogenous
staining
 The teeth are not caries prone
Radiographic features:
 Enamel appears reduced in bulk, often showing
a thin layer over occlusal and interproximal
surfaces
 Dentin and pulp chambers appear normal
Treatment:
 Full crown coverage for aesthetic concerns

DISTURBANCES IN
STRUCTURE OF DENTINE.
DENTINOGENESIS IMPERFECTA.
Definition:

Dentinogenesis imperfecta is an autosomal-dominant trait
affecting the dentine, with variable expressivity. Affects both
dentitions.
Classification: 3 types

Type 1:

Dentin abnormality occurs in patients with concurrent
osteogenesis imperfecta

Primary teeth more affected than permanent teeth

Type 2: Only dentin abnormalities and no bone diseases

Type 3: Similar to type 2 but with multiple pulp exposures,
periapical radioluscencies, variable radiographic appearances.
DENTINE (cont…) DENTINE
(cont…)
Clinical features:







In both dentitions, the teeth exhibit an unusual
transluscent, opalescent appearance
Color variation from yellow-brown to gray to violet
Entire crown appears discolored because of the
abnormal underlying dentin
Enamel fractures easily, resulting in rapid wear
Overall tooth morphology unusual due to excessive
constriction at the cemento-enamel junction, giving the
crown a tylip or bell shape
Roots are shortened and blunted
Teeth do not exhibit any greater susceptibility to caries
DENTINE DEFECTS (cont…)
Radiographic features:
Type 1 and 2 exhibit identical features such as:
 Opacification of dental pulp because of
continued deposition of abnormal dentin
 Short roots
 Bell-shaped crowns
Type 3:
 Dentin appears thin
 Pulp chambers and root canals extremely large
giving the appearance of thin dentin shells=shell
teeth
DENTINE DEFECTS (cont…)
Histological features:
 Dentin contains fewer but larger and irregular dentinal
tubules
 Dentin poorly calcified with occasional cellular inclusions
 Dentin is softer and has a greater water and inorganic
content
 Enamel appears normal
 Dentino-enamel junction is smooth instead of scalloped.
Treatment:
 Full-crown coverage (protection against tooth wear and
aesthetic concern)
DENTINE DEFECTS (cont…)
DENTIN DYSPLASIA.
Definition:
It is an autosomal-dominant trait that affects dentin. This is a rare
condition subdivided into type I (radicular type) and a more rare
type II (coronal type)

Both dentitions are affected
Similarities with dentinogenesis imperfecta:

Early obliteration of pulp chambers and root canals by atypical
dentin
Differencies from dentinogenesis imperfecta:

The teeth are normal in color

No tendency for the enamel to chip off

No rapid attrition

Altered, retarded, deficient root formation with radioluscent areas
at the apices of some teeth.
DENTINE DEFECTS (cont…)
Clinical features:
 Teeth of normal color with no attrition
 Looseness, malposition, early loss of teeth due to
retarded root formation and lack of supporting bone
Radiographic features:
Type I:
 Roots appear extremely short
 Pulps almost completely obliterated
 Residual fffragments of pulp tissue appear typically as
horizontal lucencies
 Periapical lucencies (chronic abscesses, granulomas,
cysts)
DENTINE DEFECTS (cont…)
Type II:


Deciduous teeth radiographically similar to type I
Permanent teeth exhibit enlarged pulp chambers that have been
described as thistle tube appearance
Histological features:
 The enamel and immediately subjacent dentin appear normal
 Deeper layers of dentin show atypical tubular patterns and irregular
organization
Treatment:
 The treatment is directed toward retention of teeth for as long as
possible
 The prognosis is poor due to short roots and periapical lesions.
DENTINE DEFECTS (cont…)
REGIONAL ODONTODYSPLASIA=Ghost teeth
Definition:
It is a dental abnormality that involves the hard tissues
derived from both the epithelial (enamel) and
mesenchymal (dentin, cementum and pulp)
components of the tooth-forming apparatus.

Several teeth in a quadrant or region are affected

Both mandible and maxilla can be affected

Permanent teeth more affected than deciduous

Maxillary anteriors mostly affected
DENTINE DEFECTS (cont…)

Clinical features:


The teeth exhibit short roots, open apical foramina and enlarged
pulp chambers
Eruption of the affected teeth is delayed or does not occur
Teeth have irregular shape
Hypoplastic and irregularly mineralized enamel

Radiographic features:

Wide, open apices
Pulp stones
Reduced radiopacity of the teeth
Loss of distinction between the enamel and dentine described as a
“ghostly” appearance.





DISTURBANCES IN
STRUCTURE OF
CEMENTUM.
The coronal 1/3 of the cement consists of
acellular cementum (primary) whereas the
apical 2/3 consists of cellular cementum
(secondary).
 The cellular cementum continues to be
formed throughout the life of the tooth.
 Thickness varies between individuals,
generally increases with age to
compensate for occlusal wear.

CEMENTUM DEFECTS (cont…)
HYPERCEMENTOSIS.
Definition:

This is an abnormally increased cementogenesis
Aetiology:

Some cases are idiopathic

Others may be associated with certain conditions like:

Periapical inflammation (generalized thickening or localized knoblike enlargement)

Mechanical stimulation

Functionless and unerupted teeth

Paget’s disease of bone

Hypercementosis may be associated with root ankylosis
Significance: The tooth extraction can be laborious
CEMENTUM DEFECTS (cont…)
HYPOCEMENTOSIS.
Hypoplasia and aplasia of cementum are uncommon
Hypocementum is associated with:


Cleidocranial dysplasia in which there is lack of cellular cementum
Hypophosphatasia characterized by: Reduced serum alkaline
phosphatase level, Deformities of extremities similar to those of
rickets, Failure of calcification of the calvarium
Clinical complications:

Premature loss of some or all deciduous and permanent teeth due
to poor periodontal attachment and abnormal dentine formation.
DISTURBANCES IN
STRUCTURE OF THE PULP.
PULP CALCIFICATION.









It is a common phenomenon that occurs with increasing age for no
apparent reason
There appears to be no relation to inflammation, trauma or systemic
disease
May be of microscopic size or large enough to be detected radiographically
Calcifications may be diffuse (linear) or nodular (pulp stones)
Linear calcifications are typically found in root canals, pulp stones in pulp
chambers
Can be true denticles when composed predominantly by dentin or false
denticles when they represent foci of dystrophic calcifications
Are referred to as attached pulp stones when incorporated into dentine or
free pulp stones when surrounded by pulpal tissue
Clinical significance:
None but can be problematic during endodontic therapy
OTHER DISORDERS OF TEETH
DISORDERS OF ERUPTION
AND SHEDDING OF TEETH.
1.
PREMATURE ERUPTION, NATAL AND NEONATAL TEETH.
Natal teeth are slightly more common than neonatal teeth

They are seen in +/- 1 in 3000 live births

Almost always one or two central incisors are involved

The mandible is four time more involved than the maxilla
Aetiology:

Normal tooth germ developing in a superficial position in a
superficial position in the jaw
Prognosis:

They are either lost spontaneously

Can be extracted to prevent them being inhaled or ulcerate the
tongue or the mother’s nipple

If left in the jaw, the roots may sometimes continue to develop
and the teeth become firm.

ERUPTION AND SHEDDING
(cont…)
2.RETARDED ERUPTION.
Can be associated with:
 Endocrinopathies (e.g. hypothyroidism)
 Prematurity
 Nutritional deficiencies
 Down’s syndrome
Both dentitions can be affected
Other causes involved:
 Idiopathic migration
 Traumatic displacement of tooth germs
 Abnormally large crowns
 Cleidocranial dysplasia causing delayed eruption and
multiple and impacted supernumerary teeth.
ERUPTION AND SHEDDING
(cont…)
3.PREMATURE LOSS.


Usually it is the result of either dental caries and its sequelae or
chronic periodontal disease
Occasionally associated with:-Hypophasphatasia
-Prepubertal periodontitis
-Hereditary palmar-plantar hyperkeratosis
4.PERSISTANCE OF DECIDUOUS TEETH.
 Usually associated with the failure of eruption of the permanent
successors
 Persistance of the entire deciduous dentition is uncommon
( cleidocranial dysplasia when eruption of permanent teeth is impeded)
ERUPTION AND SHEDDING
(cont…)
5. IMPACTION OF TEETH.
Definition:
An impacted tooth is one which remains unerupted or
only partly erupted, in the jaw beyond the time it should
normally be fully erupted.
 One or several teeth may be affected
 The condition may be symmetrical
 Rarely seen in primary dentition
Teeth most frequently involved are:
 Third molars
 Mandibular premolars
 Maxillary canines
ERUPTION AND SHEDDING
(cont…)
Aetiology:
Local factors:
 Abnormal position of the tooth germ
 Lack of space for the teeth
 Supernumerary teeth
 Cysts and tumours
Systemic factors: Cleidocranial dysplasia (multiple impacted teeth)
Possible complications:


Resorption of the impacted tooth or adjacent erupted teeth
Development of dentigerous cysts and odontogenic tumours
ERUPTION AND SHEDDING
(cont…)
REIMPACTION OF TEETH (Infraocclusion,
Submerged teeth).
Definition:
It is a situation in which previously erupted tooth
becomes submerged in the tissues.

The deciduous second molar most commonly affected

Mandible two times more affected than maxilla
Clinical features.

Deficient development of the alveolar process around
the reimpacted tooth which may become completely
covered by oral mucosa

The roots are usually partly resorbed and ankylosed to
the bone.
NON-BACTERIAL
LOSS OF TOOTH STRUCTURE.
TOOTH WEAR
ATTRITION.
Definition:
This is a loss of tooth substance as a result of tooth-totooth contact. It is an age-related process and varies
from one individual to another.
 It may be physiological or pathological in origin
Chronology:
 Incisal edges of the incisors are worn first
 Occlusal surfaces of the molars
 Palatal cusps of the maxillary teeth and buccal cusps of
mandibular teeth.
TOOTH WEAR (cont…)
When the dentine becomes exposed, it generally
becomes discoloured brown.
 The patient may complain of hypersensitive dentine.
 Men generally show more severe attrition than women
Aetiology:
 Abnormal occlusion
 Bruxism and habits such as tobacco and betel chewing
 Abnormal tooth structure
 Abrasive property of food

TOOTH WEAR (cont…)
ABRASION.
 Definition:
 It is a pathological wearing away of tooth
substance as a result of an abnormal use of
abrasive substances orally or abnormal use of
abrasive substances orally.
 -The location and pattern are directly
dependaent on the cause
 -The gingival 1/3, incisal edges and proximal
surfaces are more affected
TOOTH WEAR (cont…)
Aetiology:
 Tooth brush abrasion (left side more involved in
righthanded and vice versa)
 Pipe smoking
 Chewing tobacco and various foreign substances
(sand, stones)
 Use of abrasive dentifrice
 Occupational abrasion( holding objects between
or against teeth during work like thread or nails)
 Ritual abrasion
TOOTH WEAR (cont…)
EROSION.
Definition: This is loss of tooth structure from a nonbacterial chemical process
Aetiology: External or internal acids such as:

Excessive intake of acidic beverages

Sucking citrus fruits (lemons)

Occupational erosion (e.g. battery manufacturing)

Chronic alcoholism

Idiopathic erosion (acidic saliva)

The patient may complain of hypersensitive dentine.
TOOTH WEAR (cont…)
Resorption.

It can be physiological like the resorption of deciduous
teeth or microscopic areas of superficial resorption of
the roots of permanent teeth.

When the resorption is sufficient to be diagnosed
radiologically it is always pathological

It is not a continuous process, osteoclasts are not
always present.

There are 2 types: External resorption and internal
resorption
TOOTH WEAR (cont…)








Pathological external resorption may be
associated with:
Periapical inflammation
Mechanical stimulation (excessive force in
orthodontic treatment)
Neoplasms or cysts
Unerupted teeth
Transplanted or replanted teet
Idiopathic resorption
Pathological internal resorption is usually
associated with pulpitis.
DISCOLORATION OF TEETH.
Normal variation in the color of teeth must
be distinguished from pathological discoloration.
Aetiology:

Surface deposits (Extrinsic stains)

Changes in the structure or thickness of the
dental hard tissues

Diffusion of pigments into the dental hard
tissues after their formation

Incorporation of pigments into the dental
hard tissues during their formation
DISCOLORATION OF TEETH
(cont…).
Extrinsic stains:
 Substances in the diet
 Habitual chewing of betel nut or tobacco
 Tobacco smoking
 Medications
 Chromogenic bacteria
DISCOLORATION OF TEETH
(cont…).
Changes in the structure or thickness of
dental tissues







Enamel hypoplasia, fluorosis
Amelogenesis imperfecta
Enamel opacities
Enamel caries
Dentinogenesis imperfecta
Dentinal dysplasia type II
Age changes in dental tisúes
DISCOLORATION OF TEETH
(cont…).
DIFFUSIÓN OF PIGMENTS INTO DENTAL TISSÚES AFTER
THEIR FORMATION.



Extrinsic stains
Endodontic materials
Products of pulp necrosis (Lysis of necrotic tissue and red blood
cells)
PIGMENTS INCORPORATED DURING FORMATION OF
DENTAL TISSUES.

Bile pigments (Rhesus incompatibility); the color appears
yellowish-brown

Porphyrins; the color appears pinkish-brown

Tetracyclins; the color appears yellowish at eruption then darker
and browner
REIMPLANTATION OF TEETH.
Definition:
It is an avulsed tooth following traumatism that is
returned to its own socket.
Clinical features:

Usually, the pulp and soft tissues attached to the root
degenerate due to traumatic injury of the blood
supply

Sometimes the resorption is rapid but other times it
is slowly progressive up to 10-15 years

Resorption is largely a function of the length of time
the tooth has been out of the jaw.
ROOT FRACTURE.
The outcome of an intra-alveolar fracture of
a root depends on:

Presence or absence of infection

The vitality of the pulp

The position of the fragments

The degree of communition

The location of the fracture

The mobility of the coronal fragment
ROOT FRACTURE (cont…).
Healing process: It may occur in 3 patterns
 The roots fragments become united totally, or in part, by
calcified repair tissue resembling bone and/or cementum
 The fractured surfaces of each fragment become
rounded off and clothed by cementum but are not united
by calcified tissue. Fibrous tissue fills the space.
 The fractured surfaces of each fragment become
rounded off and clothed by cementum but the fragments
are widely separated. Alveolar bone fills the space.
The pulp chamber in either fragment may
become obliterated by calcified tissue.
AGE CHANGES IN TEETH.
These include changes in morphology associated with tooth wear especially
attrition and changes in structure and composition of the dental hard
tissues.
Enamel.

Tends to become more brittle and less permeable (ionic exchange)

It darken with age (absorption of organic material)
Dentine.

Continued formation of secondary dentine leading to reduction in size
or obliteration of the pulp chamber.

Dentinal sclerosis associated with continued production of peritubular
dentine resulting in root brittleness that may fracture during extraction

The dentinal sclerosis is also associated with increasing translucency
that can be used in forensic dentistry as one method of age estimation.
AGE CHANGES (cont…)
Cementum.

Gradual increase in thickness to compensate for
interproximal and occlusal attrition

The amount of secondary cementum can also be used
for age estimation
Pulp.

The volume gradually decreases due to continued
production of secondary dentine

Decreased vascularity, reduction in cellularity and
increase in collagen fibres may impair the response to
injury and its healing potential.

Prevalence of pulp stones and diffuse calcification
increase.
ODONTOMAS AND ODONTOGENIC
TUMOURS.
A. ODONTOMAS.
Definition:
It is a non-neoplastic, developmental anomally or
malformation that contains fully formed enamel and
dentine. It can be considered as dental hamartomas
containing the calcified dental tissues. Are the most
common odontogenic tumours.
There are 2 types:
 Compound odontomas: Numerous miniature or
rudimentary teeth
 Complex odontomas: Amorphous conglomerations of
hard tissues
ODONTOMAS (cont…).
Clinical features:
 Lesions of children and young adults (2nd decade of life)
 Maxilla affected slightly more often than mandible
 Compound odontomas have a tendency to occur in the
anterior jaws
 Complex odontomas in the posterior jaws
 No gender predilection
 Associated with a retained deciduous tooth, an impacted
tooth and alveolar swelling
 Generally no symptoms.
ODONTOMAS (cont…).
Radiographic features:
1.Compound odontomas:

Appear as numerous tiny teeth in a single focus

The focus is typically in a tooth-bearing area, between
roots or over the crown of an impacted tooth

As many as 200 such structures have been observed in
a single lesion
2.Complex odontomas:

Appear in the same regions but as amorphous, opaque
mass.
ODONTOMAS (cont…).
Histological features:
 Normal-appearing enamel, dentin, cementum, and pulp may be
seen in these lesions
 Prominent enamel matrix and the associated enamel organ are
often seen before final maturation of hard tissue.
Differential diagnosis:
 Other opaque jaw lesions such as: -Focal sclerosing osteitis
-Osteoma
-Periapical cemental dysplasia
-Ossifying fibroma
-Cementoblastoma
 Usually compound odontomas are self-diagnostic and complex
odontomas present a solid opacification in relationship to teeth.
B. ODONTOGENIC TUMOURS.
Odontogenic tumours are lesions derived from the
epithelial and/or mesenchymal remnants of the toothforming apparatus.
 Are therefore found exclusively in the mandible and the
maxilla
 The etiology and pathogenesis are unknown
 Clinically asymptomatic but may cause jaw expansion,
movement of teeth, root resorption and bone loss.
 Differential diagnosis can be based on age, location,
radiographic appearance
 Range from benign to malignant tumors.

ODONTOGENIC TUMOURS
(cont…)
EPITHELIAL TUMOURS.
1.AMELOBLASTOMA.
Definition:
This is a benign but locally invasive neoplasm
derived from odontogenic epithelium. It is the
commonest of the odontogenic tumours.
 Accounts for approximately 1% of all oral
tumours
 -More common in black Americans and West
Africans (6% or more of oral tumours)
AMELOBLASTOMA(cont…)
Clinical features:
 Can occur in children or the elderly but
 In industrialized countries, usually in fourth or fifth
decades of life
 In developing countries, about 10-15 years earlier
 About 80% occur in the mandible of which 70% arise in
molar region and ascending ramus, 20% in the premolar
region and 10% in the incisor region.
 In the maxilla, most also occur in the molar region, 15%
involving the antrum
 The tumour is slow-growing but locally invasive
 It is asymptomatic in early stages and can be discovered
as an incidental finding
AMELOBLASTOMA(cont…)






As the tumour enlarges, there is facial deformity and
expansion of the jaw bone
The enlargement is initially bony hard, non-tender, ovoid
or fusiform in outline
In advanced cases, egg-shell crackling may be elicited
due to thinning of the overlying bone
In late features, there is perforation of bone and
extension of the tumour into soft tissues. In maxilla, it
can expand into the sinus and beyond
Teeth may become loosened, pain is rarely a feature
In rare cases, pulmonary metastases may occur
AMELOBLASTOMA(cont…)
Malignant variants of ameloblastoma may rarely
be encountered:
-Malignat ameloblastomas: well differentiated
-Ameloblastic carcinomas: less microscopic
differentiation with cytologic atypia and mitotic
figures.
 Metastases appear usually in the lung, followed
by regional lymphnodes, the skull, liver, spleen,
kidney and skin.

AMELOBLASTOMA(cont…)
Radiographic features:
 Appears most commonly as a multilocular
radiolucency but may also be unilocular
 Roots of teeth involved show varying degrees of
resorption
 The margins are well defined and sclerotic
 May become associated with an unerupted
tooth, particularly an impacted third molar and
mimic the appearance of a dentigerous cyst
 At an early stage, can be mistaken for an
odontogenic cyst
AMELOBLASTOMA(cont…)
Histological features:
 There are 2 types: The follicular and the plexiform patterns.
a.Follicular pattern:
 The tumour epithelium is arranged into more or less discrete, round
islands or follicles, resembling the enamel organ of the developing
tooth germ
 The follicles consist of a central mass of loosely connected, angular
cells resembling the stellate reticulum of the normal enamel organ,
surrounded by a layer of cuboidal or columnar cells resembling
ameloblasts
 The nuclei are stimulated away from the basal ends of the cells=
reversed polarity
 The follicles are separated by varying amounts of fibrous connective
tissue
AMELOBLASTOMA(cont…)


Microcyst formation is common that may coalesce to form larger
areas of cystic change within the tumour
Sometimes, small areas of squamous metaplasia may occur and
then the tumour is called acanthomatous ameloblastoma
b.Plexiform pattern:




The tumour epithelium is arranged as a tangled network of
anastomosing strands and irregular masses each of which shows the
same cell layers as for foliicular pattern
Each strand or mass is bounded by columnar or cuboidal cells
resembling ameloblasts
The central area is occupied by stellate reticulum-like cells
Cystic formation is common, caused by stromal degeneration
AMELOBLASTOMA(cont…)
Pathogenesis:
 Originates within the mandible or maxilla from
epithelium involved in the formation of teeth
 Potential epithelial sources:
- Enamel organ
-Odontogenic rests (rests of Mallassez, rests of Serres)
-Reduced enamel epithelium
-Epithelial lining of odontogenic cysts (e.g. dentigerous
cyst)
-Basal layer of oral epithelium
 The trigger for neoplastic transformation totally unknown
AMELOBLASTOMA(cont…)
Differential diagnosis:
 Odontogenic tumours (calcifying epithelial odontogenic
tumour)
 Odontogenic cysts (dentigerous cyst, odontogenic
keratcyst)
 Benign non-odontogenic lesions (central giant cell
granuloma, ossifying fibroma)
Management:
 Surgical resection with a margin of normal bone
 Simple curettage is associated with high recurrence rate
(50-90%)
 Good follow-up since recurrence can appear 10-20 years
later.
ODONTOGENIC MYXOMA.
Definition:
This is a benign but locally invasive and
aggressive neoplasm. It is a mesenchymal
lesion that mimics microscopically the dental
pulp or follicular connective tissue.
Clinical features:
 -Age extends from 10 to 50 years with a mean
of about 30 years
 -No gender predilection
 -Mandible and maxilla equally affected
ODONTOGENIC MYXOMA
(cont…)
Radiographic features:
 The lesion is always lucent, the pattern may be variable
 May appear as a well –circumscribed or a diffuse lesion
 Often multilocular and has a honey-comb or a soap-bubble
appearances
 Cortical expansion or perforation and root displacement or
resorption may be seen
Histologic features:
 Stellate, fibroblast-like cells with long anastomosing processes,
separated by abundant connective tissue=glucosaminoglucans
 Some cases contain a few strands of odontogenic epithelium
 Variant amount of collagen may be present making it difficult to
distinguish between myxoid change in a fibroma and fibrous
change in a myxoma hence the terms myxofibroma and
fibromyxoma.
ODONTOGENIC MYXOMA
(cont…)
Differential diagnosis:
 Same as for ameloblastoma
Management:
 Surgical excision for complete removal but
the locally invasive growth makes it
difficult and predisposes to local
recurrence
 Prognosis is good.
CEMENTOBLASTOMA.
CEMENTOBLASTOMA.
Definition:
 It is also known as true cementoma and it is a rare benign
neoplasm of cementoblast origin.
Clinical features:
 Occurs predominantly in the 2nd and 3rd decades of life, typically
before 25 years of age
 No gender predilection
 Mandible more affected than maxilla
 Posterior region more involved than anterior
 Intimately associated with the root of a tooth
 The tooth involved is vital
 It is slowly enlarging
 May cause cortical expansion and occasionally low-grade
intermittent pain.
CEMENTOBLASTOMA (cont…).
Radiographic features:

Opaque lesion replacing the root of the tooth

Usually surrounded by a radiolucent ring representing
the periodontal ligament space and the advancing
front of the tumour

The root usually shows resorption
Histologic features:

Appears as a dense mass of mineralized cementumlike material

Intervening well-vascularized soft issue containing
numerous, large and hyperchromatic cementoblasts
CEMENTOBLASTOMA (cont…).
Differential diagnosis:
 Odontomas
 Osteoblastomas
 Focal sclerosing osteomyelitis
 Hypercementosis
Treatment:
 Surgical excision for complete removal
 Sacrifice the tooth because of the intimate
association between the root and the tumour
Prognosis: Good, recurrence not seen
OTHER ODONTOGENIC
TUMOURS

Epithelial tumours:
-Calcifying epithelial odontogenic tumour
-Adenomatoid odontogenic tumour
-Squamous odontogenic tumour
-Clear cell odontogenic tumour
Mesenchymal tumours:
-Central odontogenic fibroma
-Cementifying fibroma
-Periapical cementoosseous dysplasia

Mixed tumours (epithelial and mesenchymal):
-Ameloblastic fibroma and
Ameloblastic fibroodontoma

References
Hamilton B.G.Robinson, Arthur S.Miller (1993), Colby, Kerr and Robinson’s
Color Atlas of Oral Pathology, 4th edition, J.B. Lippincott Company, pp.3550;53-67;146-151
Joseph A.Regezi, DDS,MS; James J.Sciubba, DMD,PHD; Richard
C,K,Jordan, DDS, Msc, Phd, FRCD (C) (1999),Oral Pathology, 4th Edition,
Saunders, pp 267-288; 367-384
Soames J.V. and Southan J.C. (1999), Oral Pathology, Third Edition, Oxford,
pp 1-17; 37-48; 59;267-285