By Joseph Salvador It was a helmet-to-helmet hit and he could be seen spitting out teeth afterwards. From time to time, watching football can be a gruesome activity. Every once in a while there’s an especially violent hit or stomach-turning sight that makes you look away from the TV. The USFL is no different from the NFL in that regard. During Sunday night’s game between the Philadelphia Stars and Pittsburgh Maulers, one player got several of his teeth knocked out. Maulers wide receiver Isiah Hennie was carrying the ball up the right sideline when he got popped by Stars safety Cody Brown. It w…