This is a question that should be determined during the treatment plan.
A good rule-of-thumb is to place one implant for each tooth replaced.
Other decisive factors for the number of implants needed for success is the
quality and quantity of the patient's bone. Equally as important are the
existing anatomy of the bone and the financial resources of the patient.
Placing enough implants to restore teeth is vitally important to the long-term
success of the restoration. Simply stated, the most costly mistake is to
have an implant fail because not enough implants are placed to support the
teeth. If the number of implants is limited due to financial constraints
of the patient, then the implant treatment should be avoided or the type of
restoration must be altered.