Personal injury question

A couple of months ago, my wife bit down on a handful of
potato chips, which included a one-inch long and 1/8-inch
wide piece of plastic that crushed one of her side teeth.  
She needed a root canal and a crown, which she got, and 
which the chip company seems willing to pay for.  My wife 
seems to think that the company will offer her quite a bit 
more than the dentist bill in order to avoid a lawsuit 
(root canal was a painful procedure, etc).  She is actually 
considering getting an attorney if the chip company doesn't 
throw her some extra cash.  My question is; is there some 
dollar amount over the total medical expenses that liable 
companies tend to offer up in order to appear 'fair', and to 
avoid lawsuits?