Why are mesial serrations more worn than distal?

[Nanotyrannus35]

This is kind of an oddly specific question, but out of the four theropod teeth that I have, all of them have the mesial serrations worn down, while the distal are pristine. Is this due to feeding wear? Or environmental factors? Could it possibly be that the mesial serrations are more fragile? Thanks for any answers.

[Troodon]

Well its the denticles that first come in contact with dinner so they are probably more used.   I've also noticed on some papers that the length of the denticles on ziphodont teeth are typically a bit shorter on the mesial edge than distal.   

[patrickhudson]

Question/comment:   I don’t know if it’s more typical to have the mesial serrations of the lower teeth and maybe the distal Serrations of the upper teeth worn?  If that was the case, it would make sense since the lower jaw can only move anteriorly and not posteriorly.  Hence, the mesial side the lowers would grind up against the distal of the upper teeth - resulting in corresponding wear facets.  
this thought only makes sense if my first question is true.  

[Troodon]

 From Schubert et al. 2005 paper on wear facets. 

"Wear facets, tend to be elongated and elliptical in shape, and follow the long axis of the tooth. They vary in size from relatively small areas to much larger surfaces, with edges abutting anterior and posterior serrated keels. These are uniformly flat, and are found on labial or lingual surfaces of teeth—but not on both and not on mesial or distal surfaces."

@patrickhudson