Academic journal article Iranian Journal of Public Health

Prevalence and Pattern of Accessory Teeth (Hyperdontia) in Permanent Dentition of Iranian Orthodontic Patients

Academic journal article Iranian Journal of Public Health

Prevalence and Pattern of Accessory Teeth (Hyperdontia) in Permanent Dentition of Iranian Orthodontic Patients

Article excerpt


Background: Awareness of hyperdontia pattern/prevalence can be useful in early diagnosis and prevention by general practitioners, pediatric dentists, and orthodontists. Since the previous results regarding the pattern of hyperdontia (supernumerary teeth) are controversial, this study aimed to assess this subject among Iranian orthodontic patients.

Methods: All approved panoramic radiographs of 3374 orthodontic patients (aged 10 to 20 years old) who had visited orthodontic departments of all Tehran dentistry universities and 10 private clinics during the years 1999-2009 were investigated to establish the prevalence/pattern of hyperdontia in permanent dentition (excluding third molars). The data were analyzed using a chi-square, a chi-square goodness-of-fit, and a Fisher exact test (α = 0.05).

Results: Of die patients, 2012 were female and 1362 were male. The prevalence of hyperdontia was 0.72% (14 females [0.69% of females], 10 males [0.73% of males], female-to-male ratio = 1:1.055). The difference between the genders was not significant (P = 0.896). No double or multiple supernumeraries were found. The most common accessory teeth were mesiodens (58.3%), maxillary laterals (25%), and maxillary premolars (16.7%). Hyperdontia was significantiy more common (P = 0.000) in maxilla (there was only one mandibular accessory tooth). It was more frequent in the anterior segment (P = 0.000). However the occurrence was not significantiy different between bimaxillary right and left quadrants (P = 0.6).

Conclusion: Hyperdontia was more common in premaxilla, and the most common accessory tooth was mesiodens. Unlike eadier studies, no bilateral accessory teeth were found. Aso no gender dimorphism was discerned.

Keywords: Hyperdontia, Prevalence, Pattern, Permanent dentition, Sex dimorphism


Hyperdontia or supernumerary teeth are terms referred to any excess number of teeth or odonto- genic structures (1,2). Such teeth may develop due to unclear environmental and genetic factors (1-3), and may cause esthetic and functional complica- tions such as diastema, crowding, rotation, displa- cement, delayed eruption, or impaction of perma- nent incisors, as well as root resorption or abn- ormal root formation of the adjacent teeth, infec- tions (such as gingivitis, periodontitis and abscess formation), cystic lesions, and occlusal interfere- nces (1,3-6). Since the majority (80-93%) of su- pernumerary teeth can cause clinical complica- tions, their early diagnosis and orthodontic- /surgical intervention are of significant value in reducing the clinical problems of the adjacent permanent teeth and the installation of the occlu- sion (3,6). Thus, awareness of the prevalence and pattern of hyperdontia is of significant clinical va- lue to the orthodontists, pediatric dentists and general practitioners who usually visit children at lower ages and can contribute to early diagnosis and planning more effective long-term interdi- sciplinary therapies (7).

Few, controversial studies have reported the prev- alence of hyperdontia in permanent dentition of different populations, as ranging from 0.1% to 3.9% and it may be higher in Mongoloids or Afri- can Americans (1-3,5,8). The controversy might root in ethnical and methodological methods of those studies; for instance, reliability of findings might be improved by including older patients or increasing the sample size (4,9,10). Accessory teeth usually occur in the maxillary arch with a strong tendency to affect the anterior segment (3,11). They also tend to occur more in males (2- 4,12). Flowever, the evidence regarding the pat- tern of their development is not clear, as there is also dispute over dominance of different supernu- merary teeth, different segments (midline or lateral sides) (2-4,13). In addition, controversy exists over the role of gender as a risk factor (2-4,6,14).

To our knowledge, although the prevalence of mesiodens (a supernumerary tooth type) was eval- uated in Iran (15), overall hyperdontia prevalence among Iranians is not yet established. …

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