Supernumerary teeth are additional teeth that develop beyond the normal dentition, potentially leading to dental and orthodontic complications. These anomalies can occur in both the primary and permanent dentitions and often require a multidisciplinary approach for diagnosis and management. Understanding their prevalence, classification, aetiology, associated syndromes, and appropriate intervention is crucial for ensuring optimal patient outcomes.
Prevalence
The prevalence of supernumerary teeth varies significantly across populations, with estimates ranging from 0.1% to 3.6% in the permanent dentition (Rajab & Hamdan, 2002). The condition is twice as common in males as in females (2:1 ratio), suggesting a possible genetic influence (Sykaras, 1975).
Demographic and Population-Based Variability
Sex Distribution:
Studies consistently report a higher prevalence in males, though the exact reason remains unclear.
Ethnic Differences:
• Asian populations (e.g., Japanese and Chinese) exhibit higher prevalence rates, sometimes exceeding 3%.
• European and Caucasian populations report rates between 1% and 2%.
• African populations tend to have the lowest reported prevalence.
Primary vs Permanent Dentition:
• More frequently observed in the permanent dentition, particularly the maxillary anterior region.
• In the primary dentition, prevalence ranges from 0.3% to 1.8% (Brook, 1974).
• Primary supernumerary teeth are more commonly supplemental in form, resembling normal teeth and often exfoliating naturally.
Anatomical Distribution
Maxillary Anterior Region (Mesiodens):
• Accounts for 50–80% of cases.
• Often conical and unerupted, causing eruption failure or displacement of maxillary central incisors.
Maxillary and Mandibular Molar Regions:
• Distomolars (Fourth Molars): Supernumerary molars located distal to the third molars, usually asymptomatic.
• Paramolars: Small additional teeth adjacent to the molars, often lingually or buccally displaced.
Mandibular Incisor and Premolar Region:
• Supernumerary premolars are the second most common type, with a reported incidence of 9–21%, frequently discovered incidentally on radiographs (Cooper et al., 2012).
• Mandibular incisor supernumerary teeth are rare but may lead to crowding or spacing issues.
Classification
Supernumerary teeth can be categorised based on their morphology and location:
Morphology:
• Conical: Small, peg-shaped teeth, often erupting without complications.
• Tuberculate: Larger, barrel-shaped teeth with multiple cusps, usually unerupted and causing impaction.
• Supplemental: Resembling normal teeth, most frequently found in lateral incisor and premolar regions.
• Odontome-like: Disorganised dental tissue masses, often associated with developmental disturbances.
Location:
• Mesiodens: Found between the maxillary central incisors (most common type).
• Paramolar: Adjacent to molars, buccally or lingually placed.
• Distomolar: Posterior to the third molars.
• Peridens: Located outside the normal arch, sometimes inverted or horizontally impacted.
Aetiologies
The precise aetiology of supernumerary teeth remains uncertain, but several theories have been proposed:
• Dichotomy Theory: Suggests that the tooth bud splits during development, leading to additional teeth.
• Atavistic Theory: Proposes that supernumerary teeth represent a reversion to ancestral dentition patterns.
• Genetic Predisposition: Family studies indicate a hereditary component, particularly in syndromic cases.
• Environmental Factors: Localised hyperactivity of the dental lamina may contribute to their formation.
Associated Syndromes
Supernumerary teeth are often linked to syndromic conditions, particularly those affecting skeletal and dental development:
• Cleidocranial Dysplasia (CCD):
• Multiple unerupted supernumerary teeth, delayed exfoliation, and hypoplastic clavicles.
• Gardner’s Syndrome:
• Associated with colorectal polyps, osteomas, and numerous impacted supernumerary teeth.
• Cleft Lip and Palate:
• Developmental disruptions increase the likelihood of supernumerary incisors and premolars.
Management and Timing of Intervention
The Royal College of Surgeons of England (2020) provides clear guidelines on when intervention is necessary. Removal is recommended if supernumerary teeth cause:
• Eruption failure or displacement of permanent teeth.
• Rotation, crowding, or midline shifts.
• Pathological changes, such as cyst formation or root resorption.
• Aesthetic or functional issues, particularly in the anterior maxilla.
Optimal Timing for Extraction
Impacted maxillary incisors due to mesiodens:
• Surgical removal should be performed between 7 and 9 years of age, before excessive root development of adjacent teeth (Primosch, 1981).
• Early removal minimises the need for orthodontic traction and prevents long-term displacement.
Orthodontic Considerations Post-Extraction:
• Spontaneous eruption of the incisor should be monitored for 6–12 months.
• If no eruption occurs, orthodontic traction with an open or closed exposure technique may be required.
• CBCT imaging is recommended for precise localisation and risk assessment.
Complications of Supernumerary Teeth
Failure to diagnose and manage supernumerary teeth can result in:
• Eruption failure or displacement of adjacent permanent teeth.
• Root resorption of neighbouring teeth due to pressure effects.
• Malocclusion and spacing issues, requiring extensive orthodontic intervention.
• Cystic formation, increasing the risk of infection and requiring surgical removal.
Conclusion
Supernumerary teeth present significant challenges in orthodontic diagnosis and treatment. Early identification through clinical and radiographic assessment is crucial for preventing eruption disturbances and malocclusion. Following the Royal College of Surgeons’ guidelines, timely intervention ensures that impacted incisors and other affected teeth can be managed effectively. A multidisciplinary approach involving orthodontists, paediatric dentists, and oral surgeons is essential to achieving the best functional and aesthetic outcomes.
References
• Rajab, L. D., & Hamdan, M. A. M. (2002). Supernumerary teeth: Review of the literature and a survey of 152 cases. International Journal of Paediatric Dentistry, 12(4), 244–254.
• Sykaras, S. N. (1975). Mesiodens in primary and permanent dentitions. Journal of Oral Surgery, 33(4), 249–257.
• Brook, A. H. (1974). Dental anomalies of number, form, and size: Their prevalence in British schoolchildren. British Dental Journal, 136(12), 400-404.
• Cooper, S. C., Greene, A., & Mansour, N. (2012). A study of the prevalence and distribution of supernumerary teeth in a pediatric population. Journal of Clinical Pediatric Dentistry, 36(3), 247–250.
• Humerfelt, D., Hurlen, B., & Humerfelt, S. (1985). Hyperdontia in children below four years of age: A radiographic study. European Journal of Oral Sciences, 93(4), 154–158.
• Primosch, R. E. (1981). Anterior supernumerary teeth – Assessment and surgical intervention in children. Journal of the American Dental Association, 103(4), 631-634.
• Royal College of Surgeons of England. (2020). Management of the unerupted maxillary incisor.
Comments