Strange marking on a Nanotyrannus id help impacted?

[jikohr]

Hi Everyone!

 

I'm a little perplexed by this one. The tooth is definitely a Nanotyrannus, that much I'm sure of (Hell Creek, Powder River County, Montana) but it has a strange groove at the base near the mesial side. My best guess is that another tooth dug into it within the jaw or above the gumline. Impacted? Is that the correct dentistry term for that? Also does this count as a pathology or just damage?

Anyway, I wanted to see what you all thought if my "impact" hypothesis makes sense or if there's a better explanation.

Any insight is greatly appreciated as always!

 

[Troodon]

It appears to me that a sliver of the enamel layer broke off.   Inclined to believe it occured post mortem given that its when enamel is most brittle and the edges are crisp..  Very typical to see smaller pieces break off by the root area

[hadrosauridae]

Looks like typical, peri-depositional damage.