Are the SRAM/Truvativ chainring teeth softer than Shimano?

[Mojoman]

For the second time on a ride I had to find a rock and knock back a chainring tooth (on the middle ring) after a rock hit the ring (rock was flung up from the front wheel as I passed over a rocky and stoney section of track) and bent the tooth out of alignment.

 

I have never had to do this with my Shimano crank and have hit several rocks square on!

 

The funny thing is I did not notice the tooth catching the chain while on the bigger gears at the back (middle ring up front), only when I went down to the smaller sizes on the cassette then it was 'hooking' the chain all the time!

[brussel]

not sure. But I have to replace my Shimano rings because they are worn out. I have a truvative set that I have ridden for easily 4 times longer and they are still fine.