A 5-year prospective study of Astra single tooth implants

Aim - To evaluate the AstraTech Implant ST (Molndal, Sweden) for single too th replacement clinically and radiographically after 5 years in function. S ubjects and method - Fifteen patients (age range 16 to 48) with missing max illary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had four 13 mm and eleven 15 mm single tooth implants provided. All patients were s een at 4- to 6-monthly intervals for oral hygiene maintenance. Periapical r adiographs using Rinn holders and a long cone technique were taken at the c rown insertion and after 1 year, 3 and 5 years. Results - No implant losses were observed in 14 of the 15 patients available for evaluation. No abutme nt screw loosening or soft tissue problems were observed. At crown insertio n the mean bone level was 0.46+/-0.55 to 0.48+/-0.56 mm apical to the top o f the implant neck and there were no statistically significant changes in t he radiographic bone level over the 5 years of the study (0.36+/-0.37 to 0. 43+/-0.46 mm at year 5). One crown was recemented after 18 months in functi on and 1 crown was replaced because of a fracture to the porcelain incisal edge. Conclusion - The Astra Tech Implants ST were highly successful in sin gle tooth replacement and bone levels during 5 years of function were stabl e.