Rich, any good clock repairman can replace a tooth in a gear. Just remember that it does take skill and experience. It will run you about $50.00 for the tooth and then the cost of repairing the rest of the clock.
Stevens Clocks
October 2011
I worked in clock industry part of duty was cutting the teeth on cogs, and no they cannot be repaired.
Go to clock repairer and see what he/she can come up with by way of replacements, of course costly if they have to be made. However the repairer will tell you if they can be repaired with modern technology things must have changed in my time.
bb
September 2011
If it old, brass gears etc, might not be able to find a replacment, If it was mine, I would repair the existing gear, or make a new one. that is possibly the only way to go, get someone to repair or make a new one, depends on how much the clock is worth. Repair I would think cheapest option, But finding some one to do the work. that is another problem.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix wall clocks.