The teeth usually strip off the belt itself when they fail. No Pontiac OHC belt failures on the 15 engines that I've seen either but one on a TDi Jetta (diesel - very much an interference engine but I got away with it!) and also on a Cosworth Vega that had lost about ten teeth in a row but the cams were still in time with the crank when the belt was replaced.
IIRC, the skipped tooth incident occurred at start-up because of snow that packed in during a snow storm (no belt cover) in pre-production testing. Belt covers were added after that.
