ABNORMALITIES OF TOOTH
NUMBER WITH CLINICAL
IMPORTANCE.
Oluwatosin Ajibade
DEN/2014/010
OUTLINE
• Introduction
• Epidemiology
• Abnormalities of teeth number:
• Supernumerary Teeth
• Anodontia
• Double Teeth
• Conclusion
• References
INTRODUCTION
Tooth development and eruption involves various
complex processes. At any time during any of these
stages of development or eruption, there may be insult
leading to abnormalities in the tooth shape, structure,
number and size.
Epidemiology Of Dental Abnormalities
• The study of prevalence pattern and clinical presentation of
developmental dental hard-tissue anomalies in children with primary
and mixed dentition was done in Ile-Ife in 2014 by Dada Oluwaseyi
Temilola et al showed that;
• two hundred and seventy six (26.6%) children had dental anomalies.
Of these,
• 23.8% had one anomaly,
• 2.5% had two anomalies,
• and 0.3% had more than two anomalies.
• , 49.3% male,
• 50.7% female,
• and 47.8%, 28.6% and 23.6% were children from low, middle and high
socioeconomic classes, respectively.
Abnormalities Of Tooth Number
• The expected number of teeth in the primary dentition is 20 while 32
is expected in permanent dentition, when there is a deviation from
these that is not physiological(exfoliation and eruption in primary
dentition)it is referred to as abnormalities of teeth number.
• Anomalies in teeth number are caused by disruption in the dental
lamina formation stage of dental development.
• Anomalies in the number of teeth can occur in both primary and
permanent dentition.
ABNORMALITIES OF TOOTH NUMBER
•The abnormalities of tooth number includes
the following:
•Supernumerary teeth
•Anodontia
•Double teeth
Supernumerary Teeth
• Also known as hyperdontia or extra teeth.
• These are odontogenic structures formed from tooth germ in excess of the usual
number for any given region of the dental arch.
• Results from hyperactivity of dental lamina and can occur as a part of a
syndrome, specially cleft lip and palate, cleidocranial dysostosis and Gardner’s
syndrome. It is inherited as an autosomal dominant or X-linked trait which
explains the sex dominance.
• They may be single or multiple and unilateral or bilateral in distribution and can
occur in any region of the dental arch.
Supernumerary Teeth
• Extra teeth (supernumerary teeth) have been reported to occur in
0.2-0.8% of Caucasians in the primary dentition and 1.5-3% in the
permanent dentition in the same populations. There is a male to
female ratio of approximately 2 : 1. Patients with supernumerary
primary teeth have a 30-50% chance of these being followed by
supernumerary permanent teeth.
Supernumerary Teeth
• Supernumerary teeth occur most frequently in the premaxilla in the
midline(mesioden), or immediately adjacent to the midline and are
less common in the primary dentition than in the permanent
dentition .
• In the primary dentition, the supernumerary teeth are usually normal
or conical in shape while in the permanent dentition they have a
great variety of shapes which may be classified as :
Supernumerary Teeth
• Conical – small, peg-shaped crown
• Tuberculate – short, barrel shaped crown
• Supplemental – resembles the normal teeth
(incisiform, caniform, molariform)
• Odontome – varied shape, manifest due to disorders
of differentiation and are of two types; compound
odontome and complex odontome.
• The majority of supernumerary teeth are either
conical or tuberculate.
Supernumerary Teeth
• They can also be classified based on location.
• These include:
Mesiodens
Paramolars
Parapremolars
Distomolars
Mesioden
• Most common supernumerary tooth
• Tooth situated between maxillary central incisor
• They are often conical in shape
Parapremolars
• Extra teeth around premolars, also known as peridens
• May be located buccal or palatal to the premolar
Paramolars
• These are extra teeth around the molars
• May be located palatally or buccally
Distomolars
• Supernumerary teeth distal to the 3rd molar.
• Also referred to as distodens
Clinical Significance Of Supernumerary Teeth
The supernumerary teeth could result in the following:
• May interfere with the emergence of the adjacent tooth into the oral cavity
• Crowding
• Displacement of the adjacent tooth
• Root resorption of adjacent tooth
• Cyst formation
• Diastemas
Treatment
It depends on the type and the position of the supernumerary teeth.
• If the tooth is not interfering with the eruption of the teeth nor causing
displacement of erupted teeth, may be allowed to remain. Periodic
examination is however essential to see if any undesirable changes occur.
• If the tooth is interfering with eruption or displacement of erupted teeth,
extraction is required.
It should be noted that time is of importance in the management of
supernumerary teeth. Early diagnosis and prompt treatment is necessary for
prevention of deleterious effects on dentoalveolar structures.
Anodontia
It
is
also
called
anodontia
vera.
It
is
a
rare
genetic
disorder
•
characterized by congenital absence of all primary or
permanent teeth.
.
Anodontia
There are different types which include:
• Complete anodontia/total anodontia: This is when all teeth are
missing
• Partial anodontia/hypodontia: This is when one or several teeth are
missing.
• Pseudoanodontia: This is when teeth are absent
clinically because of impaction or delayed eruption
• False anodontia: This is when teeth have been exfoliated
or extracted.
• Oligodontia is a term used to describe a situation where multiple
usually more than six teeth are missing
Anodontia
• The cause of an isolated missing tooth is often unclear; this
may be genetic in origin or associated with some
environmental insult during development. Missing teeth
have been reported in association with multiple births, low
birth weight, and increased maternal age. Rubella and
thalidomide embryopathies may also be associated with
missing teeth
Anodontia
• Autosomal dominant inheritance of missing teeth is seen in
families with mutations in the MSX1 gene on chromosome 4.
Missing third molars and second premolars are the most
common finding. These families may also have clefting
segregating with the missing teeth. Mutations in the MSX1 gene
are also seen in the tooth-nail (Witkop) syndrome.
• A pattern of autosomally dominant inheritance of missing teeth,
particularly molars, is seen as a result of mutations in the PAX9
gene on chromosome 14.
Clinical Significance
• If it is in the anterior, it can be unaesthetic
• Patients are prone to gingivitis and caries due to food
packing in the space of the missing teeth.
• There may be drifting of the tooth adjacent or opposite to
the space
Treatment
• The care of children with multiple missing teeth can be complex and
ideally requires multidisciplinary input from pediatric dentists,
orthodontists, and prosthodontists as well as genetic counselling.
• In cases of anodontia, full dentures are required. These can be provided,
albeit with likely limited success, from about 3 years of age, with the
possibility of implant support for prostheses provided in adulthood.
• Multiple missing teeth can be treated by the use of partial dentures,
with implants as part of the treatment protocol at a later age.
Double Teeth (Connation)
• These teeth are joined together and are often described by terms
that are based on the aetiology of the anomaly.
• For instance, fusion is used to describe the union between the
enamel and the dentine of 2 or more normally separate developing
tooth germs.
• While gemination is the term used to describe the partial
development of two teeth from a single tooth bud following
incomplete division.
Double Teeth
• However it can be difficult to distinguish between fusion and
gemination on clinical grounds.
• The term connation is preferred because it describes its
appearance without suggesting the aetiology.
• Connated teeth are more frequent in the primary dentition,
and in the incisor or canine region.
Fusion
Gemination
Clinical Significance
• Arch Assymetry
• Spacing
• Poor aesthetics
• May impede the eruption of adjacent tooth
Treatment
• In the permanent dentition, surgical separation of fused teeth may be
possible with subsequent orthodontic alignment and restorative
treatment as needed to reshape the crown.
• Take a radiograph to check if there are separate pulps or not.
• Reshaping of geminated tooth may be impossible and extraction may
be the only alternative, orthodontic therapy and/or prosthetic
replacement is then required
• The groove on a double tooth is extremely prone to caries, thus
fissure sealing is essential
Conclusion
It is important that we understand the concept of tooth
number abnormalities to be able to accurately
diagnose and treat complications that arise from them.
References
• A manual of paediatric dentistry
• CAMERON paediatric dentistry
• PAEDIATRIC DENTISTRY - 3rd Ed. (2005)
OF TOOTH DEVELOPMENT AND ERUPTION BY ADEYEMO TOMILOLA
• ABNORMALITIES
AYO
• https://europepmc.org/article/MED/31636863
• https://pubmed.ncbi.nlm.nih.gov/25323952/