Im assuming that since he is in Sege Mode(boosted power), his bite strength is increased as well.If in sage mode naruto durability is increased and cannot hurt himself that easy how can he bite his finger for blood so he can summon (we have seen it in the blood prison movie) ?
This guy is right..plus it just like the 3rd raikage who nothing can hurt him order than himselfIm assuming that since he is in Sege Mode(boosted power), his bite strength is increased as well.