YENEPOYA DENTAL COLLEGE
ASSIGNMENT
NAME : NAMJITH PASHA
SUBJECT : DENTAL HISTOLOGY
ROLL NUMBER : 65
SUBMITTED TO : DR.MAJI JOSE
SUBMITTED ON : 14/10/2012
TOPIC : Enlist the developmental
disturbances affecting the size and number
of teeth enlisted by you and collect images
of the same using the internet
Developmental disturbances affecting
the size of the teeth are :
1.Microdontia
a)True generalized microdontia
b)Relative generalized microdontia
c)Microdontia involving single tooth
2. Macrodontia
MICRODONTIA
Microdontia is a condition in which teeth appear
smaller than normal. In the generalized form, all
teeth are involved. In the localized form, only a few
teeth are involved. The most common teeth affected
are the upper lateral incisors and third molars. The
affected teeth may be of normal or abnormal
morphology.
There are 3 types of microdontia:
1. True generalized microdontia
2. Relative generalized microdontia
3. Microdontia involving a single tooth
MICRODONTIA
TRUE GENERALIZED
MICRODONTIA
True generalized microdontia, in which all the teeth
are smaller than normal. According to these
authors, aside from its occurrence in some cases of
pituitary dwarfism, true generalized microdontia is
exceedingly rare
TRUE GENERALIZED
MICRODONTIA
RELATIVE GENERALIZED
MICRODONTIA
There is an illusion of
true microdontia.
RELATIVE GENERALIZED
MICRODONTIA
MICRODONTIA INVOLVING A
SINGLE TOOTH
Commonly affects the maxilla, mainly
lateral incisors and third molar. the
lateral incisors become peg shaped
MICRODONTIA INVOLVING A
SINGLE TOOTH
MACRODONTIA
Macrodontia is a condition in which any tooth or teeth appear
larger than normal for that particular type of tooth. True
macrodontia that involves the entire dentition is rare. It is
more common that there is an enlargement of a single tooth
due to a disturbance of morphodifferentiation. It should not
be confused with either taurodontism (bull teeth), fusion
(double tooth) or the jaws being relatively small, giving the
appearance of macrodontia. It is commonly associated with
gigantism.
MACRODONTIA
Developmental disturbances
affecting the number of the
tooth are :
1.Anodontia
2.Supernumerary Teeth
3.Pre-Decidious Teeth
4.Post-Permanent Teeth
ANODONTIA
In dentistry, anodontia, also called anodontia
vera, is a rare genetic disorder characterized by
the congenital absence of all primary or
permanent teeth. It is associated with the group
of skin and nerve syndromes called the
ectodermal dysplasias. Anodontia is usually part
of a syndrome and seldom occurs as an isolated
entity
Anodontia is the congenital absence of teeth and can occur in
some or all teeth (partial anodontia or hypodontia), involve two
dentitions or only teeth of the permanent dentition (Dorland's
1998). Many denominations are attributed to this anomaly:
partial anodontia, hypodontia, oligodontia, the congenital
absence, anodontia, bilateral aplasiaThe Anodontia of at least
one permanent tooth is the most common dental anomaly and
may contribute to masticator dysfunction, speech impairment,
aesthetic problems, and malocclusion Absence of lateral incisors
represents a major stereotype. Individuals with this condition
are perceived as socially most aggressive compared with people
without anodontia
ANODONTIA
SUPERNUMERARY TEETH
Hyperdontia is the condition of having supernumerary
teeth, or teeth which appear in addition to the regular
number of teeth. The most common supernumerary
tooth is a mesiodens, which is a mal-formed, peg-like
tooth that occurs between the maxillary central incisors.
Fourth and fifth molars that form behind the third
molars are another kind of supernumerary teeth
Supernumerary teeth can be classified by
shape and by position. The shapes include:
 Supplemental (where the tooth has a normal shape
for the teeth in that series);
 Tuberculate (also called "barrel shaped");
 Conical (also called "peg shaped");
 Compound odontoma (multiple small tooth-like
forms);
 Complex odontoma (a disorganized mass of dental
tissue
PRE-DECIDIOUS
TEETH
The presence of teeth in newborns is uncommon, varying from
1:6000 to 1:800 cases, occurring, in general, of two or three teeth.
The structural aspects, maturity, anatomical and functional conditions
of these uncommon teeth were not observed (Spouge and Feasby,
1966). They were considered to belong to a pre-deciduous dentition,
since 90% of natal or neonatal teeth are the same elements as future
deciduous dentition (Ronk, 1982). Thus, Spouge and Feasby (1966)
differentiated natal and neonatal teeth based on the maturity of the
structures, suggesting the term "premature teeth". The teeth or group
of teeth which are present at birth are denoted as natal dentition,
while neonatal teeth are those which erupt during the first month of
life (Massler and Savara, 1950).
The occurrence of either natal or neonatal teeth is relatively
rare. Its prevalence has been reported to be around 1 in 2000
to 3500 live births with the most common localization being
the mandibular region of central incisors (85%). Natal or
neonatal cuspids are extremely rare . These teeth are associated
with some syndromes which are also congenital such as
pachyonychia congenita (Jadassohn-Lewandowsky Syndrome)
and others also associated to problems such as cleft palate or
lipClinically, in the majority of cases, both natal and neonatal
teeth are characterized by small immature conical dental
structures, of a brown-yellowish color, with an undeveloped
root. These anomalous aspects permit great mobility,
facilitating spontaneous loss or exfoliation, with gingival edema
and inflammation, and some bleeding areas
Histologically, decalcified sections showed an immature tooth with an
irregular pattern of dentin related to the orientation of the dentinary
tubules. The enamel was hypomineralized or hypoplastic and the incipient
Hertwigs sheath was associated with little root development
NASAL TEETH
POST-PERMANENT
TEETH
The rare appearance of supernumerary teeth
after loss of permanent teeth; most teeth that
appear after extraction of permanent teeth are
due to eruption of previously impacted teeth
POST PERMANENT
TEETH
The picture below is a representation of a child
skeleton of approximately 5 years old. You will
notice the primary teeth present in the mouth.
All the adult are present in the maxilla and
mandible (jaw bones) of the child, ready and
waiting to grow into the mouth
THANK YOU