Scavenger, Predator, or Herbivore?
There was some scientific debate about whether the T. rex was a predator or a scavenger, but there is absolutely no debate that it might have been a herbivore. The current state of research is that it was probably both a predator and a scavenger.
Here is a paper providing evidence for predatory behavior:
Here we report definitive evidence of predation by T. rex: a tooth
crown embedded in a hadrosaurid caudal centrum, surrounded by healed
bone growth. This indicates that the prey escaped and lived for some
time after the injury, providing direct evidence of predatory behavior
by T. rex. DePalma et al, 2013. Physical evidence of predatory
behavior in Tyrannosaurus
Teeth too weak to bite?
There is no evidence that the teeth of the T. rex would fall out if it were to bite meat. Quite the opposite:
The structural analysis technique finite element analysis (FEA) is
employed here to investigate the functional morphology and cranial
mechanics of the T. rex skull. In particular, I test whether the skull
is optimized for the resistance of large bi–directional feeding loads,
whether mobile joints are adapted for the localized resistance of
feeding–induced stress and strain, and whether mobile joints act to
weaken or strengthen the skull overall. The results demonstrate that
the cranium is equally adapted to resist biting or tearing forces and
therefore the‘puncture–pul’ feeding hypothesis is well supported.
Finite–element–generated stress–strain patterns are consistent with T.
rex cranial morphology: the maxilla–jugal suture provides a tensile
shock–absorbing function that reduces localized tension yet ‘weakens’
the skull overall. Furthermore, peak compressive and shear stresses
localize in the nasals rather than the fronto–parietal region as seen
in Allosaurus, offering a reason why robusticity is commonplace in
tyrannosaurid nasals. Rayfield, 2004. Cranial mechanics and
feeding in Tyrannosaurus
There is also The variation of angles between anterior and posterior carinae of tyrannosaurid teeth [Reichel, 2012], but I couldn't access the paper itself. Science Daily summarizes it like this:
New research shows that the T. rex’s front teeth gripped and pulled, while the teeth along the side of the jaw punctured and tore flesh.
The estimated bite force of the T. rex:
Bite mechanics and feeding behaviour in Tyrannosaurus rex are
controversial. Some contend that a modest bite mechanically limited T.
rex to scavenging, while others argue that high bite forces
facilitated a predatory mode of life. We use dynamic musculoskeletal
models to simulate maximal biting in T. rex. Models predict that adult
T. rex generated sustained bite forces of 35 000–57 000 N at a single
posterior tooth, by far the highest bite forces estimated for any
terrestrial animal. Bates & Falkingham, 2012. Estimating maximum
bite performance in Tyrannosaurus rex using multi-body
Chlorophyll in Teeth?
I was unable to find the paper of the "scientists" who dug up a T. rex tooth and found "chlorophyll all the way to the center of the tooth". I was also unable to find any evidence that the teeth of actual herbivores would contain chlorophyll.
Herbivore vs Carnivore Teeth
This isn't a primary source, but I thought I'd include it anyway:
[H]erbivores have wide flat teeth that are adapted to grinding grass, tree bark, and other tough plant material. Wikipedia: Herbivore
This is a T. rex: