Synonyms for supernumerary teeth include hyperdontia, distodens, mesiodens, peridens, parateeth, and supplemental teeth.
Supernumerary teeth are teeth that develop in addition to the normal complement as a result of excess dental lamina in the jaws. The tooth or teeth that develop may be morphologically normal or abnormal. When supernumerary teeth have normal morphologic features, the term supplemental is sometimes used. Supernumerary teeth that occur between the maxillary central incisors are termed mesiodens, those that occur in the premolar area are peridens, and those that occur in the molar area are distodens.
Supernumerary teeth are easily identified by counting and identifying all the teeth in the jaws. They occur in 1% to 4% of the population, may have a greater incidence in Asians and Native American and indigenous populations, and occur twice as often in males. Although supernumerary teeth can arise in either the deciduous or the permanent dentitions, they are more common in the permanent dentition and can arise anywhere in either jaw. Single supernumerary teeth are most common in the anterior maxilla, where they are referred to as mesiodens, and in the maxillary molar region , whereas multiple supernumerary teeth occur most frequently in the premolar regions, usually in the mandible and usually positioned in the lingual aspect of the alveolar process.
Supernumerary teeth are usually discovered on images because they may interfere with normal tooth eruption. When a supernumerary tooth does erupt, it commonly does so outside the normal arch form because of space restrictions.
The imaging features of supernumerary teeth are variable. They may appear entirely normal in both size and shape, but they may also be smaller in size compared with the adjacent normal dentition or have a conical shape with the appearance of a canine tooth. In extreme cases, the supernumerary teeth may appear grossly deformed.
Images may reveal supernumerary teeth in the deciduous dentition after 3 or 4 years of age when the deciduous teeth have formed or in the permanent dentition of children older than 9 to 12 years. In addition to periapical images, occlusal and cone-beam computed tomographic (CBCT) images may aid in determining the location and number of unerupted supernumerary teeth. Care should be taken to review panoramic images for supernumerary teeth because these may be obscured in the anterior maxillae by the image of the cervical spine, or they may appear distorted if they lie outside the focal trough.
Multiple supernumerary teeth have been associated with numerous genetically inherited syndromes, including cleidocranial dysplasia, familial adenomatous polyposis (Gardner’s syndrome) , and pyknodysostosis.
The management of supernumerary teeth depends on many factors, including their potential effect on the developing normal dentition, their position and number, and the potential complications that may result from surgical intervention. If supernumerary teeth erupt, they can cause malalignment of the normal dentition. Supernumerary teeth that remain in the jaws may cause root resorption of adjacent teeth and their follicles may develop dentigerous cysts or interfere with the normal eruption sequence. All the preceding factors influence the decision either to remove a supernumerary tooth or to keep it under observation.
Fig.1 : Periapical images of inverted mesiodens.
Fig.2 : CBCT views of two mesiodens (arrows) erupting to the palatal aspect of the adjacent permanent central incisors.
Fig.3 : CBCT three-dimensional rendering of two supernumerary teeth in the anterior maxillae, palatal to the central incisors (arrow).
Fig.4 : Example of two supplemental teeth in the maxillary third molar area (distodens). B, Example in the mandibular third molar region.
Fig.5 : Periapical images show bilateral supplemental premolar teeth (peridens).
Fig.6 : right cross-sectional (B), and left cross-sectional
Fig.7 : Examples of mesiodens interfering with eruption of adjacent permanent teeth.