Observations on 25 patients treated with ball-retained overdentures using the Astra Tech implant system

Twenty-five adult patients with fully edentulous jaws, aged from 44 to 80 years were treated with seventy-one 3.5 mm diameter Astra Tech dental implants in the parasymphseal region. The length of these implants varied from 9 mm to 15 mm. Either two or three implants were inserted, subsequently exposed after a minimum period of 3 months, abutments and ball attachments placed. Full lower dentures incorporating gold alloy housings for ball-attachments were constructed. The average time that the implants were in situ was 4 years and 2 months, ranging from 1 year 3 months to 5 years and 7 months. Of the 71 implants placed, 67 achieved osseointegration-a success rate of 94%. The main complication was that of the ball-attachments becoming loose.