Study of Bone Preservation When OsseoSpeed™ Implants Are Placed Immediately Following Tooth Extraction

A Prospective, Randomized, Controlled Study to Evaluate Buccal Bone Preservation Using Fixture MicroThread™ OsseoSpeed™ Placed in Fresh Extraction Sockets the Maxilla.

The purpose of this study is to evaluate the clinical performance of implants placed in individuals who are about to loose one or more of their upper teeth. The main objective is to study how the surrounding bone tissue reacts to two different shapes of implants. Clinical performance, in wider terms, means esthetics and long lasting function. Half of the patients will receive a cylindrically shaped implant and the other half will receive a conical-cylindrical implant. The implants will be placed and after a healing period of 16 weeks the gum will be re-opened and the bone tissue response clinically evaluated. Permanent artificial tooth/teeth will be attached six weeks after that.

Inclusion Criteria:

• Provision of written informed consent
• At least 18 years at inclusion
• At least 20 teeth with expected functional balanced occlusion after restoration
• In need of one or more implants replacing teeth to be removed in the maxilla within region 15 to 25
• Presence of an intact extraction socket following removal of the natural tooth defined by: (1) a situation where the marginal border of the facial bone crest deviates less than or equal to 2 mm from that of the expected normal anatomy of the site/region, (2) a marginal border of a potential facial fenestration at least 3 mm apical of the marginal bone crest
• Presence of an extraction socket anatomy, following removal of the natural tooth, suitable for both cylindrical and conical/cylindrical implants

Exclusion Criteria:

• Untreated rampant caries and uncontrolled periodontal disease
• Absence of adjacent (mesial and/or distal) natural tooth root
• Uncontrolled diabetes (subjects history does not reveal the absence of control of insulin-dependent / non-insulin dependent Diabetes Mellitus)
• Current alcohol or drug abuse
• 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
• History of radiation in the head and neck region
• History of chemotherapy within 5 years prior to surgery
• Unable or unwilling to return for follow-up visits for a period of 3 years and 6 months
• Unrealistic esthetic demands
• Unlikely to be able to comply with study procedures according to Investigators judgement
• Involvement in the planning and conduct of the study (applies to both Astra Tech staff or staff at the investigational site)
• Previous enrolment in this study