Supernumerary teeth are additional teeth that develop beyond the standard count of 20 primary or 32 permanent teeth. Identifying and recording these extra teeth, a condition known as hyperdontia, is necessary for proper dental treatment planning and record-keeping. Labeling involves describing their physical appearance and location, followed by assigning a standardized notation for clinical charting. This process is crucial because supernumerary teeth can cause complications such as delayed eruption, displacement, or crowding of the normal dentition.
Classification Based on Form
The initial step is classifying the tooth’s morphology, grouping supernumerary teeth based on their crown and root structure. The most common form is the conical type, characterized by a small, peg-shaped crown and a simple root structure. These teeth are frequently found in the anterior maxilla and are the most likely type to erupt spontaneously into the mouth.
Another distinct type is the tuberculate supernumerary, which often presents with multiple cusps or tubercles, giving it a barrel or invaginated shape. These teeth are typically paired and are less likely to erupt, often delaying the emergence of the permanent teeth they are near. Tuberculate forms usually have delayed or rudimentary root development compared to the teeth in the normal arch.
The supplemental supernumerary perfectly resembles a tooth in the normal series, possessing the expected size and shape. These may look like a duplication of an adjacent tooth, such as an extra lateral incisor or premolar. The final morphological label is the odontome, which is not a true tooth but a disorganized mass of dental tissue. Odontomes can be further classified as compound, containing multiple small, tooth-like structures, or complex, which is a single, amorphous mass of enamel, dentin, and cementum.
Classification Based on Position
Supernumerary teeth are also categorized by their specific anatomical location within the dental arch. The most frequently encountered supernumerary tooth is the mesiodens, located in the midline between the two maxillary central incisors. The mesiodens accounts for the majority of all reported cases and is typically conical in form, though it can sometimes be inverted or horizontally impacted.
In the posterior regions of the mouth, supernumerary teeth are labeled based on their proximity to the molars. A paramolar is an extra tooth situated near a molar, commonly found buccally (cheek side) or palatally (palate side) to the maxillary molars. These are usually small and rudimentary, rarely having the full morphology of a typical molar. The term distomolar, or fourth molar, is reserved for a supernumerary tooth that develops just distal (behind) the third molar.
The term perimolar or parapremolar describes an extra tooth located in the premolar region, often found between the first and second premolars. While paramolar and distomolar describe positions adjacent to the molars, the perimolar label specifies a location within the bicuspid zone. These positional names are descriptive labels that allow dental professionals to communicate the location before assigning a formal clinical code.
Standardized Numbering Notation
Descriptive labels must be translated into a standardized numbering notation for clinical charting and insurance claims. Dental professionals rely on three major systems globally: the Universal Numbering System (UNS), the FDI World Dental Federation Notation (ISO 3950), and the Palmer Notation. The UNS, widely used in the United States, assigns permanent teeth the numbers 1 through 32.
In the UNS, a dedicated range of numbers is used to distinguish supernumerary teeth from the normal 32 teeth. Permanent supernumerary teeth are commonly assigned a number between 51 and 82, corresponding to the adjacent normal tooth plus 50. For instance, a supernumerary tooth located next to tooth number 1 (the upper right third molar) would be designated as number 51, and the sequence continues around the arch. For primary dentition, the letter ‘S’ is typically added as a suffix to the letter of the nearest deciduous tooth, such as “AS” if the extra tooth is near the primary upper right second molar (Tooth A).
The FDI World Dental Federation Notation uses a two-digit code where the first digit identifies the quadrant (1-4 for permanent, 5-8 for primary) and the second digit identifies the tooth’s position from the midline (1-8). Because the system does not have an officially designated quadrant for supernumerary teeth, two methods are commonly used in practice. Some professionals simply continue the tooth sequence beyond the standard 8, such as labeling a fourth molar in the upper left quadrant as “2.9” or “2.10”.
Another common method for FDI charting is to add a descriptive suffix like “ST” (for supernumerary tooth) to the two-digit code of the nearest tooth. The Palmer Notation, often used by orthodontists, uses a bracket symbol to denote the quadrant and a number (1-8) or letter (A-E) to denote the tooth. In this system, supernumerary teeth are labeled by placing a letter or number suffix next to the standard notation of the tooth they are closest to, such as “5.A” for a supernumerary near the permanent upper right second premolar (Tooth 5).