OID and joins

Hi all.

Can I use OIDs for joins between tables without losing functionality?

The problems I am afraid of are:

    - pg_dump/psql: Can I recover OIDs from security copies?.
    - Indexes: joins between tables linked with OIDs use indexes from
      OIDs?, should I have to make that indexes or they are automatic?.
    - Any other limitation I don't achieve to view?.

Thanks for your ideas.

                            David