Nando is 9 months old now. (He is a GSD) Do they go through a second teething stage at this age or should I take him for a check-up? He has started chewing quite manically, is if his teeth are hurting him again. I've frozen all his kongs for him as well as making a few teething rags and it has eased off quite a bit. We have generally had toy breeds in the past and usually expect a second bout of teething but I'm not 100% sure with the GSD.
Several factors, could be changes in the mouth and teeth formation, their heads have ages to go to grow and change , boredom , does he get enough to do , sexual maturity..naughty teenager syndrome.
Around 9 months the teeth 'bed down' and the desire to chomp on stuff can start again. Keep the kongs available and rope tuggies so he can take it out on them and anything precious or valuable keep away from him. It usually lasts a month or so then it should settle down.