This study reports on 99 magnetic retention units (root caps and minimagnets) were used to stabilise overdentures in 66 patients. Tooth mobility, root caries, periodontal health, denture function, integrity of root caps and minimagnets were evaluated 4-12 years after insertion. The results showed a marked reduction in root mobility (increased stability in 86% of the roots), but extraction of 8% of the roots. After 116 months the survival rate calculated according to Kaplan and Meier was 79% for roots, 90% for caps and 77% for minimagnets. Nine per cent of the roots demonstrated caries and 10% discoloration of the root caps.