Chewing is a way for dogs to either entertain, cope, or warn themselves or their family and each one should be handled separately before a dog will stop chewing.
As puppies, chewing is a way to play, learn, and explore with their world. A lot of times puppies learn how to not bite hard through their littermates playing together. If one nips too hard the other will yelp and this will alert the puppy that he went too far. But chewing on items is harder because they need to chew to soothe teething pains.
As dogs grow they should learn what to chew and what to avoid but this is not always the case. There are a couple of things every dog owner should know when it comes to issues with naughty doggy behavior.
First, it could be just boredom, the dog might not have enough stimulant to keep them entertained through toys or exercise.