Decision to modify the product under study as a result of feedback regarding subjective feeling during installation procedure. For more info, see brief summary.

The primary objective of the study is to evaluate the long-term survival rate of individual implants and prostheses when treating edentulous upper jaws of poor bone quality with Fixture MicroThread™ (Micro-Macro).

Clinical study recruitment was stopped in year 2000 due to a decision to modify the product under study. This was a result of feedback regarding the subjective feeling during the installation procedure. There were no safety concerns w/r to the study products. Patients already included and treated in the study were monitored for the full duration of the study in accordance with the clinical study protocol.

Inclusion Criteria:

• 18 - 75 years of age
• Bone quality class III or IV, (according to Lekholm & Zarb16)
• Willing to give signed informed consent

Exclusion Criteria:

• Need for bone augmentation of the maxilla
• Tobacco smoking more than 5 cigarettes/day
• Any systemic disease or condition that would compromise post-operative healing and/or osseointegration
• Systemic corticosteroids or any other medication that would compromise post-operative healing and/or osseointegration
• Unable or unwilling to return for follow-up visits
• Bruxism or other parafunctional activity