There's no clear video of the incident as of now (and the NHL is searching for it) but here's Carcillo's postgame interview with the media, describing his version of the events.
Savard claimed that, during the scrum, Carcillo had his hand in his mouth and was attempting to perform an amateur tooth extraction. From James Murphy of NESN:
"He pummeled my face, pulled on my teeth, so I guess that's biting when a guy tries to pull your teeth out like [he did]," Savard claimed. "I don't know. I don't see how that is biting. Yeah, I mean, he embellishes stuff. Obviously, under the pile, you try to pull out my front teeth, so if that's a bite then I don't know what to say."
But, in the end, if the NHL can't find any visual evidence of the "bite," it's simply a matter of he-said, he-said, and there will be no supplemental punishment.