IMPLANT-SUPPORTED OVERDENTURES - THE BIRMINGHAM EXPERIENCE

Objectives: The use of an implant retained overdenture with magnets of fers a simple treatment approach to the problem of instability of the complete denture. Advantages with magnets include a simplified clinica l technique and reduced lateral stresses on the abutments. This paper reports on a long-term study undertaken at Wordsley Hospital and Birmi ngham Dental teaching hospital in the West Midlands. Methods: Twenty-o ne patients received implant-retained overdentures with magnets over a 5-year period. The average age of the patients was 63 years (range 44 -83 years). Seventy-eight Astra (Astra Tech AB, Molndal, Sweden) impla nts were placed: 17 patients had four, two had three and two had two i mplants placed.Results: During the 5-year study, 11 implants were lost , one from infection, and the remaining 10 were lost because of a fail ure of osseointegration. This equates to an 86% success rate which inc reases to 97% when implants shorter than 1 cm are discounted. Over thi s period, the average number of dentures constructed per patient was 2 .3. The main reason for denture replacement was a loss of function of the magnets. When the steel casing around the magnets was breached, th en corrosion resulted. The life expectancy of the magnets over the 5-y ear period was 77 weeks (+/- 50 weeks). One denture was replaced due t o problems of instability. Patient satisfaction with the treatment rem ains high, and all patients can now wear dentures satisfactorily. Conc lusions: The use of a magnet retained overdenture offers a simple reco nstructive approach to complete denture instability. Methods are curre ntly being investigated to improve the clinical function and durabilit y of the magnets. The success rate with the implants remains good afte r 5 years in function. (C) 1997 Elsevier Science Ltd.