Study Comparing OsseoSpeed™ Implants of Two Different Lengths in the Upper and Lower Posterior Jaw

Inclusion Criteria: * Provision of informed consent * Aged 20-70 years at enrolment * History of edentulism in the study area of at least four months * Neighboring tooth/teeth to the planned bridge must have natural root(s) * Presence of natural teeth, partial prosthesis and/or implants in the opposite jaw in contact with the planned bridge. * Deemed by the investigator to have a bone height of at least 11 mm and a bone width of minimum 6 mm * Deemed by the investigator as likely to present an initially stable implant situation Exclusion Criteria: * Unlikely to be able to comply with study procedures, as judged by the investigator * Earlier graft procedures in the study area * Uncontrolled pathologic processes in the oral cavity * Known or suspected current malignancy * History of radiation therapy in the head and neck region * History of chemotherapy within 5 years prior to surgery * Systemic or local disease or condition that could compromise post-operative healing and/or osseointegration * Uncontrolled diabetes mellitus * Corticosteroids or any other medication that could influence post-operative healing and/or osseointegration * Smoking more than 10 cigarettes/day * Present alcohol and/or drug abuse * Involvement in the planning and conduct of the study (applies to both Astra Tech staff and staff at the study site) * Previous enrolment in the present study. * Severe non-compliance to protocol as judged by the investigator and/or Astra Tech * Simultaneous participation in another clinical study, or participation in a clinical study during the last 6 months