Download was normal.

Amelogenesis Imperfecta
Definition: Genetic disturbances in enamel formation leading to
altered morphology of enamel. There is normal dentin and pulp
formation. The teeth will appear yellowish brown. There are four
general types (hypoplastic, hypocalcified, hypomaturation, and
hypomaturation-hypocalcified with taurodontism). Below I’ve
described general findings of amelogenesis imperfecta and not for one
specific type.
Location: Enamel.
Edge: Well-defined.
Shape: Thin (or completely absent) to normal thickness of
enamel. Crowns tend to have a ‘square’ shape with multiple open
contacts present.
Internal: If enamel is present, it is radiopaque but is the radiopacity of
dentin (which is less than normal forming enamel).
Other: None.
Number: Associated with all teeth in the oral cavity.
Amelogenesis Imperfecta
(note the square shape and thin enamel present)
Enamel hypoplasia
Enamel hypoplasia, limited to a single tooth, is known as Turner's
Hypoplasia and the affected tooth is termed Turner's tooth. The most
frequently affected teeth are the permanent maxillary incisors and the
maxillary and mandibular premolars. Common causes for the condition
include local trauma or infection derived from an overlying deciduous
tooth. Clinical appearance can range from mild, opaque chalkiness or
brown discoloration or frank enamel pitting (Figure 48).
Figure 48.
In contrast to the genetic nature of Turner's Hypoplasia, environmentallyinduced developmental failure of enamel formation affecting multiple
teeth is termed generalized environmental enamel hypoplasia.
Environmental factors can include nutritional deficiencies, excessive
fluoride ingestion, and severe, fever-producing childhood diseases.
Clinically, the affected teeth show localized enamel deficiency ranging
from focal opacification to severe pitting. The distribution of enamel
defects reflects the chronology of enamel formation with most severely
affected areas representing the area that were forming at the time of the
environmental influence.
The radiographic features of generalized environmental enamel
hypoplasia consist of linear bands of relatively radiolucent enamel (Figure
49). Mild opacification and focal surface pitting may not be visible on
radiographs.
Figure 49.
Dentinogenesis imperfecta
Dentinogenesis imperfecta is an uncommon defect in the collagen formation that is
transmitted as an autosomal dominant trait.1 It was probably first recognized by
Barret in 1882. The first published report describing the disorder as an enamel
defect was by Talbot as quoted by Witkop.2 The term ‘hereditary opalescent dentin’
was first used by Skillen2, Finn3 and Hodges4 to describe the brown translucent teeth
that have an opalescent sheen and are lacking in pulp chambers. This condition
causes teeth to be discolored (most often a blue-gray or yellow-brown color) and
translucent. Enamel may be thinner than normal in this condition. Thus the teeth are
also weaker than normal, making them prone to rapid wear, breakage, and loss.
These problems can affect both primary teeth and permanent teeth.5
CASE REPORT
A 22year old male patient, visited the Department of Oral Medicine and Radiology,
Seema Dental College and Hospital, Rishikesh with a chief complaint of pain in the
lower right and upper left back tooth region since 1 month. Intraoral examination
showed missing 11, 13, 21, rotated 22, and carious 16, 17, 26, 36, 46, 47.
Generalized attrition was observed. Gingiva was soft and edematous with loss of
stippling. A generalized yellow-brown discoloration of teeth was also observed. (Fig.
1) Based on generalized yellow-brown discoloration and attrition of teeth, a clinical
diagnosis of dentinogenesis imperfecta was made.
Orthopantomogram (Fig. 2) showed the following features: Short and slender roots,
constricted neck, prominent in posterior teeth, increased contrast between crown
and root, and generalized obliteration of pulp canal. (Fig. 3 & 4) Radiographic
features were characteristic and confirmed the clinical diagnosis of dentinogenesis
imperfecta.
DISCUSSION
Dentinogenesis imperfecta is a genetic disorder of tooth development. It is inherited
in an autosomal dominant pattern, which means one copy of the altered gene in
each cell is sufficient to cause the disorder. In most cases, an affected person has
one parent with the condition. Dentinogenesis imperfecta affects an estimated 1 in
6,000 to 8,000 people. It occurs with equal frequency in both sexes. It usually
affects whites.5
Dentinogenesis imperfecta has been subdivided into three types: Type I occur in
people who have osteogenesis imperfecta, a genetic condition in which bones are
brittle and easily broken. In type II there is no associated osteogenesis imperfecta;
and when the condition is associated with the Brandywine triracial isolate and large
pulp chambers, it is classified as type III.
Some researchers believe that dentinogenesis imperfecta type II and typeIII, along
with a condition called dentin dysplasia type II, are actually forms of a single
disorder. The signs and symptoms of dentin dysplasia type II are very similar to
those of dentinogenesis imperfecta. However, dentin dysplasia type II affects the
primary teeth much more than the permanent teeth.6
Clinically, the appearance of the teeth with dentinogenesis imperfecta is
characteristic. They show a high degree of amber like translucency and a variety of
colors from yellow to blue-gray. The colors change according to whether the teeth
are observed by transmitted light or reflected light.5 Affected teeth have broad
crowns with constriction of cervical area resulting in tulip shape.7 The enamel easily
fractures from the teeth and the crowns wear readily. In adults they may frequently
wear down to the gingiva. The exposed dentin becomes stained. The color of the
abraded teeth may change to dark brown or even black. Some patients demonstrate
an anterior open bite.5
Radiographically the teeth appear solid, lacking pulp chambers and root
canals.7 Radiographs may also reveal slight to marked attrition of the occlusal
surface. The roots are usually short and slender. Early in development, the teeth
may appear to have large pulp chambers, but these are quickly obliterated by the
formation of dentin. Ultimately the root canals may be absent or threadlike.
Occasional periapical radiolucencies are seen in association with sound teeth without
evidence of pulpal involvement, which may occur from microscopic communication
between residual pulp and the oral cavity. These lesions do not occur as frequently
as in dentin dysplasia. The architecture of the bone in the maxilla and mandible is
normal.5
Histologically the dentin is composed of irregular tubules, often with large areas of
uncalcified matrix. The tubules tend to be larger in diameter and less numerous in a
given volume of dentin than in normal teeth.7
Dentin dysplasia is another autosomal dominant condition in which
there is markedly disturbed dentin formation. This extremely rare
condition occurs in two distinct patterns. The first, referred to asradicular
dentin dysplasia, is characterized by partial or complete obliteration of
the pulp chamber and extremely short, blunted roots (Figure 45). When
persistent, the pulp chamber displays a characteristic crescent.
The second type is coronal dentin dysplasia and is characterized by the
thistle-funnel pulp chamber enlargement in the permanent teeth (Figure
46).
REGIONAL ODONTODYSPLASIA
All the deliveries of the mother (a total of nine deliveries) were normal. The mother
had urinary infection during pregnancy. The mother had been smoking
a packet of cigarettes every two days, including the
pregnancy period. When the patient was one year old,
he had had convulsions and had been prescribed Depakin (SANOFI-SYNTHELABO)
for four years, and
then the medicine had been withdrawn. He had not
been taking any medications for a year when he attended our clinic. Medical
examinations did not reveal
any systemic problems and he was in a generally good
condition. He had speech disorder and his facial skin
was normal.
In clinical examination, although the upper half of
the face was normal, there was asymmetry in the
lower half (Figure 1). There were no abnormal findings in the nails and eyes. In the
maxillary arch, there
were partially erupted left primary lateral incisors,
canines, and first and second molars and right primary
second molars in addition to the right first permanent
molars. The other permanent incisors, canines, premolars and molars were
unerupted. In the mandibular
arch, only the right first and second primary molars
and the right incisor were present; these teeth were
clinically normal. The lower right primary lateral incisor and canine, left primary
central and lateral incisors, canine, first and second molars were absent
(Figure 2a and 2b)
In panoramic radiographic examination (Figure 3a)
and periapical radiograph
The decayed teeth were restored. Maxillary left primary first molar tooth and maxillary right
primary
second molar received full crowns (Figure 4), and
partial dentures were fabricated for upper and lower
jaw (Figure 5). Oral hygiene instructions and dietary
All the deliveries of the mother (a total of nine deliveries) were normal. The mother had
urinary infection during pregnancy. The mother had been smoking
a packet of cigarettes every two days, including the
pregnancy period. When the patient was one year old,
he had had convulsions and had been prescribed Depakin (SANOFI-SYNTHELABO) for four
years, and
then the medicine had been withdrawn. He had not
been taking any medications for a year when he attended our clinic. Medical examinations
did not reveal
any systemic problems and he was in a generally good
condition. He had speech disorder and his facial skin
was normal.
In clinical examination, although the upper half of
the face was normal, there was asymmetry in the
lower half (Figure 1). There were no abnormal findings in the nails and eyes. In the maxillary
arch, there
were partially erupted left primary lateral incisors,
canines, and first and second molars and right primary
second molars in addition to the right first permanent
molars. The other permanent incisors, canines, premolars and molars were unerupted. In
the mandibular
arch, only the right first and second primary molars
and the right incisor were present; these teeth were
clinically normal. The lower right primary lateral incisor and canine, left primary central and
lateral incisors, canine, first and second molars were absent
(Figure 2a and 2b)
In panoramic radiographic examination (Figure 3a)
and periapical radiographs (Figure 3b), the maxillary
dentition and right region of mandibular dentition
were normal. The teeth in the left region of mandibular dentition had thin radiopaque
contours with no
distinction between enamel and dentin, and wide pulp
chambers, giving a ‘ghost-like’ appearance. The
crowns of the affected teeth were surrounded by large
radiolucent areas, probably representing enlarged
dental follicles. Diagnosis of RO was made on the
basis of the clinical and radiographic findings.
a
b
Figure 2. Intraoral images of maxillary (a) and
mandibular (b) arches of the patient.
ab
Figure 3. Panoramic (a) and periapical (b) radiographs
of the patient.
Figure 4. Intraoral image of the patient after delivery of
Figure 1. Frontal view of the patient. full crowns.
JODDD, Vol. 3, No. 4 Autumn 2009 A Case of Regional Odontodysplasia
recommendations were given. The patient was called
in at certain intervals (once every 6 months).
Discussion
The etiology of RO is not known exactly. However, it
143
has been reported that some medications administered
for systemic and local reasons might play a role in the
etiology of this disease.
1-3,5,8
Although the precise
etiological factor in this case is unknown, the pattern
of involvement suggests that the unknown damaging
factor has been persistent, presumably starting before
birth and continuing to act right through the period of
development of the lower permanent incisors and
canines.
Odontodysplasia is often seen in both permanent
and primary dentitions.
6,7,12,13
Generally, the disorder
is localized to one arch and maxilla is involved twice
as often as mandible.
14
However, in this case, the teeth
demonstrating odontodysplasia were in the lower
arch. In both maxilla and mandible, central and lateral
incisors, and canines are the teeth most commonly
affected.
4,6,10,12,13,15
In the case we presented in addition to incisors, canines and molars were involved,
which makes the case more interesting.
Teeth with RO sometimes may not be distinguished
from the ones with dentinogenesis imperfecta. There
is a generally familial involvement history in dentinogenesis imperfecta. In addition, there is
remarkable
hypoplasia in enamel in regional RO, which is not the
case in dentinogenesis imperfecta.
13
Although conditions such as dentinal dysplasia and amelogenesis
imperfecta show some similarities to RO, these conditions affect the entire dentition
without segmental
involvement. When the affected teeth erupt, RO can
be mistaken for dental caries; therefore, the teeth
might be extracted without being submitted for histological examination.
14
Many cases of RO are also
misdiagnosed as malformed teeth or odontomas.
16
There are various ideas about the treatment of odontodysplasia. While a number of
clinicians suggest that
the teeth affected should be immediately extracted and
dentures should be fabricated, some other clinicians
recommend restorative procedures in an attempt to
protect the affected teeth as soon as possible.
Figure 5. Intraoral image of the patient after fabrication
of partial dentures for upper and lower jaws.
1
Those
who suggest the extraction of the teeth claim that the
teeth affected become, most of the time, abscessed,
and painful, and defective enamel and dentin cannot
be protected against bacterial invasion; as a result, the
risk of developing necrosis and facial cellulitis may be
high in near future.
3
Those who suggest restorative
procedures recommend that the involved teeth should
be restored and preserved in the mouth. Teeth with
delayed eruption should be preserved in the mouth
during skeletal growth. Severely damaged permanent
teeth with pulpal involvement can be extracted and
dentures can be fabricated.
13
We believe the affected teeth in these patients
should be restored as much as possible and retained in
the mouth. However, severely damaged permanent
teeth with pulpal involvement should be extracted and
dentures fabricated, if necessary, to provide function
and esthetics for the patients.
SUBMITTED BY
SAFNA CTK.