I use large river rocks for gaps at the bottom of our fence. My two would dig in the sand to cool off or get warm. They never really dug at the edge of the fence.
I have also used zipties and extra pieces of chain link fence to patch the weird spots in a hurry.
Beta as a rescue would try to gnaw on my moulding corners or the trim wood on my staircase. I found the edible Nylabones were a great distraction and took about 2hrs to eat. The teething nylabones were either too soft or hard and would cause gums to bleed. The edible ones are the only Nylabones I use.
Caesar has eaten a hole in the carpet all the way to the pad. Sometimes training is the only way to go when natural insticts come in. It turned out that there was a crack in the concrete under the carpet and he always tried to sniff there. Now when he displays that "making the bed" or scratching activity I alwasy try to stop him before he gets started.
I found basic training to be wonderful. It helped me understand Caesar better and to stop saying "no" all the time. It also taught Caesar the differences between play time and time to listen.
Hope that helps a bit!! Good Luck….basenji teething time is always a trying time!!