Thursday, 10 May 2012

By tooth or by beak...

Researchers at the University of Sheffield and King's College London have discovered that the pufferfish, a highly poisonous but silly looking tropical fish, may hold the key to how and why humans do not replace their teeth in adulthood - which may in turn lead to advances in dental treatments.

Certain adult pufferfish have a parrot like 'beak' with a distinct cutting edge. This beak is formed by bands of dentine which continually grow to replace those lost through feeding.  In young pufferfish, the beak is not present, instead 'first-generation' teeth develop, only to be replaced by four teeth at the front of the jaw which subsequently make-up the beak structure.

 Figure 1: A, the freshwater pufferfish, Monotrete abei. B, side-view 
showing the large lips covering the beak. C & D, views of the beak itself. 
Photo courtesy of Fraser et al (2012: 2)

According to Dr Gareth Fraser, who led the project, investigating the manner and mechanisms of tooth replacement is of  "great interest for science... to understand the genes that govern the continued supply of teeth and mechanisms of dental stem cell maintenance."

Humans only replace their teeth once, in childhood.  Unlike a shark with its many rows of teeth, or a rat with it's continually erupting ones, humans cannot replace teeth naturally. The much increased longevity of modern human populations is therefore at odds with the single set of trauma-and-disease-prone adult teeth they have. Dr Fraser believes that the knowledge could eventually be used to "facilitate advances in dental therapies" with this in mind. 

Fraser, GJ, Britz, A, Johanson, Z and Smith, M. 2012. Replacing the first-generation dentition in pufferfish with a unique beak. PNAS. 
Available at:
University of Sheffield press release. 
Available at:


  1. Really very interesting post... and blog!! Congratulations! I linked it at


  2. Hey Jordi, thanks for the link - I'm glad you liked my blog, it's a bit silly sometimes, but I enjoy writing it! :)


  3. I had fun choosing this particular painting online that now hangs in my downtown office, from, who sells canvas prints of art masterpieces. While the original is treasured in some art museum in England, my print, of this painting by Edward Burne-Jones is very much appreciated by my staff and clients. The print quality is really excellent.