Assuming yours is a freewheel setup, I'd recommend you re-dish and re-space. This results in a stronger real wheel, in addition to more even distribution of stress across the axle.

My story - once upon a time, I had a Sachs-Maillard 7-speed freewheel with broken teeth on the smallest cog. As it so happened, I also needed a 6-speed freewheel for the Carlton I was rebuilding.

I'd managed to un-thread the smallest and second-smallest cogs (which were nested together), using a pair of chain-whips, but I just could not remove the smallest from the second smallest. The chain whips were too close, and the missing teeth on the smallest cog meant that my leverage options were limited.

Out came the Dremel tool and the 20" huge adjustable wrench. I used the Dremel cutting wheel to chop some teeth off of the smallest cog, such that there were two parallel flat spots to wrench against. It then became a simple matter of screwing the second cog to the bench top, then using the 20" adjustable to break the innermost cog with the chopped-off teeth loose.