Here is an effective method of sharpening planer blade. It overcomes dents anytime. It requires very affordable tooling (grinding wheel) and a fairly heavy and straight piece of iron angle. And then patience!
I can sharpen more than planer blades, such as chisel, jointer blades, etc
The grinding wheel can be found at Lee Valley Tools
http://www.leevalley.com/en/Wood/page.aspx?p=32981&cat=43072,45938
