A 5-year prospective study of Astra single tooth implants

Aim - To evaluate the AstraTech Implant ST (Molndal, Sweden) for single tooth replacement clinically and radiographically after 5 years in function. Subjects and method - Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had four 13 mm and eleven 15 mm single tooth implants provided. All patients were seen at 4- to 6-monthly intervals for oral hygiene maintenance. Periapical radiographs using Rinn holders and a long cone technique were taken at the crown 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 abutment screw loosening or soft tissue problems were observed. At crown insertion the mean bone level was 0.46+/-0.55 to 0.48+/-0.56 mm apical to the top of the implant neck and there were no statistically significant changes in the 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 function and 1 crown was replaced because of a fracture to the porcelain incisal edge. Conclusion - The Astra Tech Implants ST were highly successful in single tooth replacement and bone levels during 5 years of function were stable.