Oligodontia has been reported to be the most or one of the most common developmental dental anomalies. The severity and pattern of oligodontia has been shown to affect craniofacial morphology, a situation with obvious implications for preprosthetic orthodontic treatment. Given the associations between developmental pathways and tissue homeostasis, it is fascinating that oligodontia may be used as a marker for malignancy and hitherto unreported congenital malformations. This article discusses the etiology, prevalence, and consequences of oligodontia, followed by a review of approaches to treatment depending on the presentation of the patient.
No consensus concerning the nomenclature of agenesis of teeth exists in the literature. The most frequently used terms to describe tooth agenesis are hypodontia and oligodontia . Hypodontia is usually employed to describe a situation in which only a few teeth are missing, whereas oligodontia is used when a large number of teeth are missing. Nevertheless, The Glossary of Prosthodontic Terms makes no distinction between the two terms with respect to the number of teeth missing. In medicine, the Greek prefix hypo- denotes an abnormally low level of a substance in the body. The prefix oligo- , also Greek, denotes few. Because teeth are structures present in discreet numbers, the authors believe that oligodontia is the most appropriate term to describe the congenital absence of more than one tooth but not all teeth, and that the Tooth Agenesis Code may be used to assign a unique value to the pattern of agenesis. The term anodontia is reserved to describe the total absence of teeth, a use for which there seems to be no dispute.
Etiology of oligodontia
Oligodontia is thought to have a significant genetic basis because it is associated with mutations in several genes, the protein products of which regulate odontogenesis. Oligodontia may also be associated with environmental influences.
Prevalence of oligodontia
Oligodontia has been reported to be the most or one of the most common developmental dental anomalies, which probably explains why the prevalence of oligodontia is one of the few topics in the literature for which there is good evidence supported by meta-analyses. The prevalence of agenesis of permanent teeth in a meta-analysis of 28 studies covering Europe, Australia, and whites in North America was found to differ by continent and gender. Overall, oligodontia occurred 1.37 times more frequently in females than in males. Oligodontia was more prevalent in Australia (females: 7.6%; males: 5.5%) and Europe (females: 6.3%; males: 4.6%) than in North American whites (females: 4.6%; males 3.2%). Mandibular second premolars were found to be absent more frequently than maxillary lateral incisors or maxillary second premolars ( Fig. 1 A–T). Moreover, maxillary lateral incisors were found to be absent more frequently bilaterally than unilaterally, whereas the opposite was true for maxillary first and second premolars and mandibular second premolars.