Microdontia is a condition in which one or more
teeth
A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...
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 incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...
s and
third molar
The third molar, commonly called wisdom tooth, is the most posterior of the three molars in each quadrant of the human dentition. The age at which wisdom teeth come through ( erupt) is variable, but this generally occurs between late teens a ...
s.
Teeth affected by microdontia may also have abnormal shape, and the abnormal size may affect the whole tooth, or only a part of the tooth.
Definition
Males tend to have larger teeth than females,
and tooth size also varies by race.
Abnormal tooth size is defined by some as when the dimensions are more than 2
standard deviation
In statistics, the standard deviation is a measure of the amount of variation of the values of a variable about its Expected value, mean. A low standard Deviation (statistics), deviation indicates that the values tend to be close to the mean ( ...
s from the average.
Microdontia is when the teeth are abnormally small, and
macrodontia is when the teeth are abnormally large.
Classification
There are 3 types of microdontia:
True generalized
All the teeth are smaller than the normal size. True generalized microdontia is very rare, and occurs in
pituitary dwarfism
Growth hormone deficiency (GHD), or hyposomatotropism, is a medical condition resulting from not enough growth hormone (GH). Generally the most noticeable symptom is that an individual attains a short height. Newborns may also present low blood su ...
.
Due to decreased levels of
growth hormone
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in ...
the teeth fail to develop to a normal size.
Relative generalized
All the teeth are normal size but appear smaller relative to enlarged jaws.
Relative generalized microdontia may be the result of inheritance of a large jaw from one parent, and normal sized teeth from the other.
Localized (focal)
Localized microdontia is also termed focal, or pseudo-microdontia. A single tooth is smaller than normal.
Localized microdontia is far more common than generalized microdontia,
and is often associated with
hypodontia
Hypodontia is defined as the developmental absence of one or more teeth excluding the Wisdom tooth, third molars. It is one of the most common dental anomalies, and can have a negative impact on function, and also appearance. It rarely occurs i ...
(reduced number of teeth).
The most commonly involved tooth in localized microdontia is the maxillary lateral incisor, which may also be shaped like an inverted cone (a "peg lateral").
Peg laterals typically occur on both sides,
and have short roots.
Inheritance may be involved,
and the frequency of microdontia in the upper laterals is just under 1%.
The second most commonly involved tooth is the maxillary third molars,
and after this
supernumerary teeth
Hyperdontia is the condition of having supernumerary teeth, or teeth that appear in addition to the regular number of teeth (32 in the average adult). They can appear in any area of the dental arch and can affect any dental organ. The opposite ...
.
Causes
There are many potential factors involved.
Others include trichorhinopharyngeal, odontotrichomelic, neuroectodermal and dermo-odontodysplasia syndromes.
Treatment
Unerupted microdonts may require surgical removal to prevent the formation of
cyst
A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubb ...
s.
Erupted microdonts, peg laterals especially, may cause cosmetic concern. Such teeth may be restored to resemble normal sized teeth,
typically with
composite
Composite or compositing may refer to:
Materials
* Composite material, a material that is made from several different substances
** Metal matrix composite, composed of metal and other parts
** Cermet, a composite of ceramic and metallic material ...
build ups or
crown
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...
s.
Orthodontics
Orthodontics (also referred to as orthodontia) is a dentistry specialty that addresses the diagnosis, prevention, management, and correction of mal-positioned teeth and jaws, as well as misaligned bite patterns. It may also address the modificati ...
may be required in severe cases to close gaps between the teeth.
Epidemiology
Females are affected more than males,
and the condition occurs in permanent (adult) teeth more than deciduous (baby teeth or milk teeth).
References
External links
Developmental tooth disorders
{{oral pathology