Study to Compare Survival for ASTRA TECH Implant System, OsseoSpeed™ Implants Following Immediate Loading in Extraction Sockets Versus Immediate Loading in Healed Ridges

Inclusion Criteria: * Provision of written informed consent * 18 years of age and over * A minimum of 20 stable intra occlusal contacts after planned restoration * In need of single standing implants replacing missing / extracted / avulsed teeth in the maxilla within zone 15 to 25 Exclusion Criteria: * Untreated rampant caries and uncontrolled periodontal disease * Use of smoking tobacco at time of inclusion * History of pre-surgical bone augmentation, within 4 months, in the planned implant area * History of extraction without augmentation, within 3 months in the planned implant area * Absence of opposing dentition * Absence of adjacent (mesial and/or distal) natural tooth * Uncontrolled diabetes * Known pregnancy at time of inclusion * Present alcohol or drug abuse * Any systemic or local disease or condition that would compromise post-operative healing and/or osseointegration * Need for systemic corticosteroids or any other medication that would compromise post-operative healing and/or osseointegration * Unable or unwilling to return for follow-up visits for a period of 5 years * Unrealistic esthetical demands * Unlikely to be able to comply with study procedures according to Investigators judgment * Already included in this study