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Kindred87 t1_jaa2t14 wrote

Current understanding in regenerative medicine is that regeneration of that level will probably end up leveraging cellular bioelectric networks instead of DNA. DNA is responsible for dictating the hardware of your anatomy (e.g. proteins) and bioelectric networks are responsible for dictating morphological goals (i.e. grow a finger of this shape starting here). One way of triggering regeneration of teeth will involve modifying bioelectric circuits in your jaw tissues to instruct the cells there to build the tooth that was built previously.

The handy thing about this is that once the circuit is modified, your cells automatically do the rest of the work according to the anatomical mapping contained in the circuit. Including stopping once the structure (tooth) matches the stored mapping.

https://www.science.org/doi/10.1126/sciadv.abj2164

Edit: To directly answer your questions in the context of a theoretical bioelectric repatterning therapeutic:

  • Identifying the exact pattern that results in adult tooth formation and the drug combination that can induce said pattern. It's worth noting that there are multiple types of teeth (canine, molar, etc.) that each have a unique bioelectric pattern.
  • Potentially local scarring and other biological processes that obstruct regeneration.
  • By specifying the pattern for the desired tooth.
  • The tooth would regenerate along a similar timeline as the initial formation of the tooth. Months, if not years. There may be a way to accelerate this process, but it hasn't been identified yet to my knowledge.
  • Once initiated, it would continue independently. You would likely have regeneration checkups to verify that the growth is proceeding as expected to rule out perturbations in the bioelectric patterns that would result in deformities.
  • The procedure wouldn't stop without deliberate intervention, whether surgery to extract the regenerating tissues or modifying the pattern to change the morphological goal from building a tooth to being standard jaw tissue. In the latter case, while it's possible that the cells would automatically revert, I'm only aware of tissues reorienting or "moving" to the target location following perturbation in the case of embryogenesis.
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leoyoung1 OP t1_jaaub1b wrote

Thank you SO much for such an in depth answer to the challenges. How close are we to being able to do this? Is this something that is actually being researched, or better yet, developed?

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Kindred87 t1_jaaxok5 wrote

If you check the link, limb regeneration was achieved in frogs (that don't naturally regenerate) over a year ago. There're other experiments that have produced ectopic organs in tadpoles like extra eyes, hearts, and brains, though it's not as hard to accomplish in an organism that's already undergoing morphogenesis. Limbs are a good research target for morphogenesis in non-regenerative adults because they're isolated anatomically, are external, and feature a wide range of tissues including nerves.

There are studies underway on mice though growing limbs takes a while so it will take another year or three before we see the results of that.

However, the neat thing about this approach is how lateral it is with other anatomical structures. Because it's a top down approach that offloads the work to your cells, the same mechanisms for growing a limb can be used to grow an eye, liver, cartilage, or whatever. Again, this has been proven in tadpoles already. Once limbs are figured out other anatomical structures, like teeth, will quickly follow.

That all said, full in vivo regeneration is probably still another decade or two out from being available as an outpatient service. You'll probably have synthetic teeth produced via 3D printing, stem cell production, or cellular scaffolding before you're regrowing your teeth yourself.

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leoyoung1 OP t1_jab1scw wrote

The paper is fascinating. And just a little intimidating.

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