Why this proposal is a bad one :

Cryonics is based upon a working technology, cryogenic freezing of living tissues.

The latest cryonics techiques use M22, an ice crystal growth inhibitor that has been used to preserve small organs and successfully thaw them. More than likely, if you were to rewarm some of the tissues from a cryonics patient frozen today, some of the original cells would still be alive and viable. I don't know if this particular experiment has been performed, however : there is a reason why cryonics has a bad reputation for pseudoscience.

If you dehydrate a mammalian cell and then add water again, it's still dead. If you freeze and rewarm, heating and cooling at a rapid enough rate to prevent ice crystal growth, not only is the cell alive, but it can be more viable than newer cells later. Cryogenically frozen sperm or ova from a young person can be more viable than the same substance obtained from the same person later in life.

There are further improvements to cryonics that have not been made because it lacks the funding and resources it deserves.

Better cryoprotectants are more than likely possible. Better techniques are almost certainly achievable. The method used to preserve a viable rabbit kidney used extremely rapid cooling. Cooling the brain more rapidly might yield better results. There are potentially revolutionary improvements possible.

Allegedly, a Japanese company claims that oscillating magnetic fields prevent orderly crystal growth by water. They have experimental results and succes in preserving human teeth this way. If this method is viable, cryonics could use very large magnets on the human brain and potentially get perfect preservations with demonstrable proof of viability. http://www.teethbank.jp/ http://singularityhub.com/2011/01/23/food-freezing-technology-preserves-human-teeth-organs-next/

The first source I think is a better one : As far as a google search will tell me, this is the only existing human tooth bank in the world. If the teeth weren't viable it seems unlikely that credible dentists would be attempting the transplants and succeeding. (I think the technology being used is a lot better indication of it being legitimate than papers or singularity hub articles)