Wisdom teeth, also known as third molars, are the final set of molars to emerge in the back of the mouth. These teeth make their appearance during late adolescence or early adulthood, generally between the ages of 17 and 25. The presence and eruption patterns of wisdom teeth can vary significantly among individuals.
The Usual Number of Wisdom Teeth
Most adults develop up to four wisdom teeth, with one located in each of the four corners of the mouth. This is considered the standard number for these third molars. However, it is common for individuals to have fewer than four wisdom teeth, or even none at all. Studies estimate that between 20% and 35% of people worldwide have fewer than four wisdom teeth, a condition referred to as hypodontia or agenesis of wisdom teeth.
Understanding Supernumerary Wisdom Teeth
Supernumerary teeth are extra teeth. When these are wisdom teeth, an individual has more than the usual four third molars. Having more than four wisdom teeth falls under the broader dental anomaly known as hyperdontia, which refers to the presence of any excess teeth. These additional teeth can appear in various locations within the dental arch and may differ in shape or size from typical teeth.
How Rare is Six Wisdom Teeth?
Having six wisdom teeth is exceptionally uncommon. While the overall prevalence of supernumerary teeth (hyperdontia) ranges from approximately 1% to 4%, the specific incidence of extra wisdom teeth is considerably lower. Having more than four wisdom teeth is rare, affecting less than 5% of the population. Cases of individuals having more than eight wisdom teeth are extremely rare. This makes the presence of exactly six wisdom teeth an unusual finding, even within the rare category of hyperdontia.
Causes and Considerations for Extra Wisdom Teeth
The development of extra wisdom teeth stems from a combination of genetic and developmental factors. Genetic predisposition plays a significant role, with extra teeth often observed in relatives. Specific gene mutations, such as those in MSX1, MSX2, and AXIN2, have been linked to supernumerary tooth formation.
Certain genetic syndromes, including Gardner’s syndrome, cleidocranial dysplasia, and cleft lip and palate, also increase the likelihood of developing additional teeth. Developmental anomalies, such as hyperactivity of the dental lamina—the tissue responsible for tooth formation—can also lead to the creation of extra tooth buds. Rarely, fusion of two tooth buds or incomplete division of a single tooth bud can result in what appears to be an additional tooth. The exact cause is not always clear, suggesting a complex interplay of various factors.
Individuals with extra wisdom teeth may face several oral health issues. These additional teeth can lead to impaction, where they do not fully emerge from the gum line, causing pain or infection. Crowding of existing teeth is another common issue, potentially leading to misalignment and orthodontic problems.
Extra teeth can also make maintaining proper oral hygiene more challenging, increasing the risk of cavities and gum disease. They may also be associated with the formation of cysts or tumors in the jawbone. Dental professionals monitor such cases to prevent complications and determine if removal is necessary.