Abstract Title

ARE WE GOING TO HAVE WISDOM TEETH IN THE FUTURE?

Lead Author Affiliation

University of the Pacific, Dugoni School of Dentistry, San Francisco CA, USA

Lead Author Status

Faculty/Staff/Researcher

Presentation Category

Research, Literature Review

Introduction/Context/Diagnosis

Up to 70 % of modern humans may experience problems with their third molars, whether it is a failure of eruption (impaction) or not developing at all (agenesis). Third molar agenesis dates back to at least early Homo erectus and is seen with an increasing frequency during later evolution of Homo species. Furthermore, while most researchers associate changes in physical properties of food with an increased frequency of missing third molar, it is unclear whether this change took place during the advent of agriculture, the beginning of industrialization or both. Also, a considerable variation exists in the prevalence of a missing third molar among recent human populations in different geographical locations.

Methods/Treatment Plan

Using search engines PubMed, Science Direct, and Google Scholar articles related to third molar agenesis were collected, reviewed, and evaluated for this presentation. The following keywords regarding third molar agenesis were used: congenitally missing, agenesis, development, prevalence, etiology, genetics, and evolution. Fifteen most relevant articles were selected for this review.

Results/Outcome

The third molar is the most common congenitally missing tooth in humans. The prevalence rate of third molar agenesis varied among different countries. The highest prevalence of the third molar absence was reported in Koreans (41%), while native Africans and American Indians showed the lowest prevalence of 10-11%. Other studies reported a prevalence of 38.4% in Bangladesh, 28.7% in China, 26.2% in Malaysia, 25% in Spain, 24.75% in Chile, 17.3% in Turkey and 12.7% in England. PAX9 and MSX1 are the most important genes controlling tooth development in its early stages.They code for important transcription factors involved in genetic and signaling networks of epithelial and mesenchymal cells of the primordial tooth follicle and in epithelial-mesenchymal interactions. Mutations of these genes can lead to tooth agenesis.

Significance/Conclusions

One example of striking morphological change that has occurred during human evolution is the increasing frequency of missing third molars called “M3 agenesis”. Overall, the lack of tooth development results from interactions between multiple genetic and anatomical/functional environmental factors. Mutations in PAX9 and MSX1 genes constitute a strong genetic component of tooth agenesis in general. M3 agenesis is a fascinating example of recent biological change in humans. We know very little about how and why it happens. It deserves a more thorough investigation.

Format

Event

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ARE WE GOING TO HAVE WISDOM TEETH IN THE FUTURE?

Up to 70 % of modern humans may experience problems with their third molars, whether it is a failure of eruption (impaction) or not developing at all (agenesis). Third molar agenesis dates back to at least early Homo erectus and is seen with an increasing frequency during later evolution of Homo species. Furthermore, while most researchers associate changes in physical properties of food with an increased frequency of missing third molar, it is unclear whether this change took place during the advent of agriculture, the beginning of industrialization or both. Also, a considerable variation exists in the prevalence of a missing third molar among recent human populations in different geographical locations.