Restoration field

A Restoration Field was a device that could restore people and objects to their natural state.

A restoration field was added to the Pandorica so that the Doctor would be unable to escape by dying. It was instead used by the Doctor, once he escaped, to reanimate the nearly dead Amy Pond, though to restore a near dead living being it needed a sample of the living being's DNA. In Amy's case, this came from her younger self.

It later reanimated a Stone Dalek and the Doctor used it to revive himself when the Dalek shot him, nearly killing him. It is unknown where the Doctor got the DNA to heal himself, though since the Pandorica was already open, it is possible he did not need it.

River song said that a restoration field on its own could not restore the universe, which shows that the only way to restore the universe with a restoration field, was to use it in conjuction which caused the explosion that destroyed the universe.

With the universe destroyed, the Doctor planned to use the restoration field to "reset" the universe. By flying the Pandorica into the heart of the TARDIS's explosion, the light was spread throughout the universe at every point in time, resetting the universe and also reversing the total event collapse. (DW: The Big Bang)