tissue regeneration is the renewal to tissue damage or disturbance, it occurs mainly in limb development creatures, this makes them resilient to natural changes that will cause damage or disturbance to the tissue. 
tissue engineering is the combination of cells, physio-chemical and biochemical factors replace tissue artificially.

 William Haseltine, founder of human genome sciences, founded the first regenerative medicine in 1992.

http://en.wikipedia.org/wiki/Tissue_engineering
http://www.utwente.nl/mira/research/tissue_regeneration/
http://www.lifecell.com/health-care-professionals/lifecell-products/allodermr-regenerative-tissue-matrix/allodermr-tissue-matrix-defined/tissue-regeneration/

scientist have found new methods to speed up tissue regrowth, the body can regenerate new tissue exactly where the body need new tissue, so the body is doing most of the work but the new technique allows tissue regeneration process to speed up so the person can be on their way faster.