I liked the idea so much I tested it, although as I had stated I just didn't think it would work.
Before you view the results keep in mind my needles are extremely small gauge so they probably aren't the right tool for the job. But remember small needle small hole. Big needle big hole.
Hardwoods; Forget it. Couldn't penetrate any of the ones tested and I tested about 5 oak being one of them. At least with my needles. You might go to a feed store and get a bigger needle BUT . . . . read on.
Softwoods; Tested pine and cedar and was able to get slight penetration but, here's that but I was referring to, the water just squirts back out of the wood and I don't believe any of it penetrated.
I think that getting the needle in a hardwood is possible you cluod even drill a teeny tiny pilot hole but I think water penetration between the fibers would be a high hurdle to jump. If anyone tries it with a bigger needle please let us know what your results are. Removing dents from wood has never crossed my mind until this post but it seems like a wide-open market for someone who comes up with an effective process.
Dave you might be on to something you certainly have the right idea. Find a way to make those fibers take the water and maybe the dent will be minimized at least. I don't know how in the world you could ever get H20 in a cell again to re-inflate enough of them to "uncrush" a fiber strand though.