shared_ptr as class member

It's common to declared contained objects as a pointers to that class, while "forward declarating" them in header file. This in order to reduce physical dependencies in code.

For example

class B;  // forward declaration   

class A {
   private:
      B* pB;
};

Would it be good idea to declare such a member as shared_ptr, instead of naked pointer?

I would prefer scoped_ptr, but AFAIK it it won't be in standard.