Supernumerary teeth, also known as extra teeth, are teeth that are additional to the normal number of teeth. Most people have 20 primary teeth and 32 permanent teeth. Supernumerary teeth are teeth that exceed this normal number. They can occur in both dentitions, but are more common in permanent teeth. Supernumerary teeth may erupt normally or remain impacted in bone. They can occur unilaterally or bilaterally in the maxilla, mandible, or both. The prevalence of supernumerary teeth varies between 0.1% to 3.8% in permanent dentition and 0.3% to 0.6% in primary dentition.
What are supernumerary teeth?
Definition and terminology
Supernumerary teeth are defined as any teeth in excess of the normal full complement of 20 deciduous and 32 permanent teeth. They are also referred to as hyperdontia, supernumeraryodonts, or extra teeth. Supernumeraries can be found in almost any region of the dental arch and may assume a normal orientation or be inverted or take on an abnormal path of eruption.
Etiology and genetic factors
Several theories have been proposed to explain the etiology of supernumerary teeth:
- Phylogenetic theory – Supernumeraries represent a regression orthrowback to extinct primates with a larger number of teeth in the dentition.
- Dichotomy theory – Tooth germs may split into two homologous teeth resulting in a supernumerary tooth.
- Hyperactivity theory – Increased and localized hyperactivity of dental lamina leads to an additional tooth bud.
- Genetic theory – Supernumerary teeth can exhibit an autosomal dominant inheritance pattern in some families. Genetic factors are supported by the higher prevalence in close relatives.
Both genetic and environmental factors are likely involved in the development of supernumerary teeth. Certain syndromes and developmental disorders demonstrate an increased tendency for supernumerary teeth including cleidocranial dysplasia, cleft lip and palate, Gardner’s syndrome, Ehlers-Danlos syndrome, and Crouzon’s disease.
There are several classification systems that can characterize supernumerary teeth based on morphology and location:
- Supplemental – Supernumerary tooth of normal shape and size that replicates a normal tooth type.
- Conical – Peg-shaped tooth with a cone-like crown commonly found between incisors.
- Tuberculate – Barrel-shaped tooth with multiple tubercles or cusps. Often found posteriorly.
- Compound odontoma – Mass of disorganized dental tissues that can contain enamel, dentin, cementum and pulp tissue.
Supernumerary teeth may also be classified based on specific location such as:
- Mesiodens – Located in the maxillary anterior region between the two central incisors.
- Paramolar – Found buccal to the maxillary molars, usually rudimentary.
- Distomolar – Located distal to the third molars at the distal end of the dental arch.
The presence of supernumerary teeth can lead to a variety of complications including:
- Impaction and delayed eruption of permanent teeth
- Crowding, diastema, or displacement of erupted permanent teeth
- Abnormal eruption sequence
- Localized malocclusion
- Increased risk of dental caries if supernumerary tooth is irregular
- Cystic lesions around crown of unerupted supernumeraries
- External root resorption of adjacent teeth from pressure
- Displacement of teeth into ectopic positions like the maxillary sinus
- Nasal eruption of mesiodens or other anterior supernumeraries
Early diagnosis and management aims to prevent these potential issues related to supernumerary teeth.
Diagnosing supernumerary teeth
Supernumerary teeth may be diagnosed based on clinical examination and radiographic findings. Signs and symptoms that can indicate the presence of extra teeth include:
Signs and symptoms
- Delayed eruption or complete failure of eruption of permanent teeth
- Displacement of permanent teeth from their normal arch position
- Crowding or distortion of the occlusion localized to one region
- Midline diastema with no apparent etiology
- Alterations to normal eruption patterns and sequence
- Supernumerary teeth visible on intraoral exam
- Lack of space for eruption of permanent teeth
- Presence of odontogenic cyst or tumor
Radiographs are recommended to confirm the presence of supernumeraries, determine the precise location, orientation, anatomy, and any associated pathology. Useful radiographic views include:
- Periapical radiographs – detailed visualization of anterior supernumeraries
- Occlusal radiographs – identification of inverted supernumeraries or tuberculate morphologies
- Panoramic radiograph – single view of entire dentition and jaws
- CBCT – 3D localization and characterization if conventional radiographs are insufficient
Assessment should include adjacent structures to identify any resorption or displacement of adjacent teeth. Serial radiographs may be necessary to track eruption status.
Comprehensive treatment planning
After clinical and radiographic examination, the treatment plan addresses:
- Number, morphology, and precise location of the supernumerary teeth
- Orientation and state of eruption
- Stage of root development of adjacent permanent teeth
- Signs of resorption, displacement, impaction, or cystic lesions
- Overall occlusion and space analysis
- Need for surgical removal, orthodontics, restorative treatment
Management of supernumerary teeth
Treatment of supernumerary teeth includes observation, surgical removal, orthodontics, and restorative care.
Observation may be appropriate if the supernumerary tooth is unerupted and not causing any complications. Periodic radiographic monitoring is advisable to detect any changes. However, most authorities recommend early removal.
Extraction is usually indicated for:
- Prevention of delayed eruption or impaction of permanent teeth
- Correction of localized malocclusion or displacement
- Prevention of cyst formation in association with supernumerary
- To facilitate eruption of permanent teeth
- Removal of any associated pathology
- Improve aesthetics if supernumerary is irregular
Surgical extraction requires anesthesia, removal of overlying bone, and may involve raising soft tissue flaps for visibility. Complications include damage to adjacent teeth, maxillary sinus perforation, and risk of fracturing tuberculate supernumeraries during removal.
Timing of removal
- Primary dentition – As soon as supernumerary is diagnosed
- Mixed dentition – Before adjacent permanent teeth begin root development
- Permanent dentition – After root development of adjacent permanent teeth
This helps minimize damage to developing permanent tooth follicles while allowing spontaneous eruption.
Pre-surgical orthodontic treatment can create space for surgical access. Post-surgical orthodontics helps guide eruption and resolve crowding. Early management of crowding can preserve space.
Composite veneers or porcelain restorations may be utilized to mask unaesthetic supernumerary teeth not needing removal. More significant malocclusion following removal may require fixed prosthodontic restoration after surgical recontouring.
Regular clinical and radiographic follow-up is essential to confirm continued eruption of permanent teeth and normal occlusion following supernumerary treatment.
Prognosis of supernumerary teeth
With early diagnosis and management the prognosis is very good, with minimal effect on the developing permanent dentition. However, delayed treatment can result in:
- Displacement, rotation, impaction of permanent teeth
- Loss of arch perimeter from crowding
- Insufficient space for complete eruption
- Increased malocclusion requiring orthodontics or restorative treatment
- Greater challenges to obtain ideal functional occlusion
Therefore, early identification and removal of supernumeraries before significant root development of adjacent permanent teeth provides the most favorable long-term outcome. Appropriate supplemental orthodontic treatment can then guide eruption into proper alignment with relatively easy correction of localized spacing discrepancies. The overall objective is to allow normal maturation of the permanent dentition.
Frequently Asked Questions
What are some characteristics of supernumerary teeth?
Supernumerary teeth are extra teeth beyond the normal full complement of teeth. They can vary in morphology from normal-shaped supplemental teeth to conical or tuberculate teeth. Supernumeraries are more common in men and often found in the anterior maxilla.
What problems can be caused by extra teeth?
Potential problems include impaction, delayed eruption, diastema, crowding, root resorption, cysts, malformed adjacent teeth requiring extraction, displacement, abnormal eruptions paths, and aesthetic issues.
How are supernumerary teeth diagnosed?
Diagnosis involves clinical and radiographic examination, looking for delays in eruption, midline diastemas, distorsions in occlusion, and tooth crowding. Periapicals, panoramic radiograph, and CBCT can reveal presence and position.
When should extraction of supernumerary teeth be done?
Primary teeth are removed soon after diagnosis. Permanent teeth should be removed prior to significant root development of adjacent teeth to minimize risk. Timing prevents damage to developing permanent teeth.
How are impacted supernumeraries surgically removed?
Removal is done under local anesthesia. Soft tissue flaps and bone removal provide access. Complications include damage to adjacent teeth and fractures. Follow-up confirms continued proper eruption.
What is the likely outcome when supernumeraries are left untreated?
Prognosis declines with late treatment. Impaction, loss of arch length, inadequate space, increased malocclusion, and need for orthodontics or restorations become more likely if surgical removal is delayed.
How can supernumerary teeth be prevented?
There are no definitive preventive measures for supernumerary teeth since the cause is not completely understood. However, early detection through radiographs allows for better outcomes with timely treatment. Genetic counseling may play a role in certain syndromes.