Multicenter Study Comparing OsseoSpeed TX With OsseoSpeed EV.

Inclusion Criteria: 1. Provision of Informed Consent. 2. 18 -75 years at enrollment. 3. In need of implant(s) replacing missing tooth/teeth in the maxilla or in the mandible (no edentulous jaws). 4. History of edentulism in the planned implant area of at least 3 months (at Visit 2). 5. At least 4 months of healing after last grafting procedure in the planned implant area (at Visit 2). 6. Deemed by the investigator to be suitable for one stage surgery and be likely to present an initially stable implant situation i.e. have a bone height and bone width suitable for the chosen study implants. 7. Deemed by the investigator to be suitable for loading after 6-8 weeks. 8. Deemed by the investigator to have a "functional" opposing dentition at the time of loading the implants i.e. an even distribution of contacts between the teeth in the opposite jaw and the planned permanent crown/bridge. Exclusion Criteria: 1. Unlikely to be able to comply with study procedures, as judged by the investigator. 2. Uncontrolled pathological processes in the oral cavity. 3. Untreated, uncontrolled caries and/or periodontal disease. 4. Known or suspected current malignancy. 5. History of radiation therapy in the head and neck region. 6. History of chemotherapy within 5 years prior to surgery. 7. Systemic or local disease or condition that would compromise post-operative healing and/or osseointegration, as deemed by the investigator. 8. Uncontrolled diabetes mellitus. 9. Corticosteroids or any other medication that would compromise post-operative healing and/or osseointegration. 10. Smoking more than 10 cigarettes per day. 11. Present alcohol and/or drug abuse. 12. Current need for bone grafting and/or augmentation in the planned implant area. Local, minor soft tissue grafting will be allowed. 13. Involvement in the planning and conduct of the study (applies to both Astra Tech staff and staff at the study site). 14. Previous enrollment in the present study. 15. Simultaneous participation in other clinical studies at enrollment (Visit 1) and during the subject's first year of this study.