Multi Centre Study Comparing OsseoSpeed TX With OsseoSpeed

Inclusion Criteria: 1. Provision of informed consent 2. Female/male aged 18 years and over 3. History of edentulism in the study area of at least 3 months 4. In need for implant(s) replacing missing tooth/teeth in the maxilla 5. Deemed by the investigator to be suitable for one stage surgery 6. Deemed by the investigator to be suitable for loading after 10-12 weeks 7. Deemed by the investigator as likely to present an initially stable implant situation. 8. Deemed by the investigator to have a "functional" opposing dentition at the time of loading the implants. 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. Known or suspected current malignancy 4. History of radiation therapy in the head and neck region 5. History of chemotherapy within 5 years prior to surgery 6. Systemic or local disease or condition that would compromise post-operative healing and/or osseointegration 7. Uncontrolled diabetes mellitus 8. Corticosteroids or any other medication that would compromise post-operative healing and/or osseointegration 9. Present alcohol and/or drug abuse 10. Current need for bone grafting and/or augmentation in the planned implant area 11. Involvement in the planning and conduct of the study (applies to both Astra Tech staff and staff at the study site) 12. Previous enrolment in the present study. 13. Simultaneous participation in another clinical study, or participation in a clinical study during the last 6 months.