A comparison of hydroxylapatite coated implant retained fixed and removable mandibular prostheses over 4 to 6 years

In a 6-year prospective clinical study, 181 hydroxylapatite coated endosseo us dental implants were placed into the anterior mandible of 48 patients. T wenty-one patients were treated with fixed prostheses and 27 patients with an overdenture. When the implants were exposed all 181 had integrated. To d ate, there is 100% survival of all implants and they all retain a functioni ng prostheses. The initial results were very promising, in both groups the interval success was over 95% in the first 4 years of the study. However, b y year 6, the interval success rates had fallen to 83% for both the fixed a nd removable groups. This study also compares the construction and maintena nce complications for the two types of restorations. The clinical time take n, after implant exposure, to construct the prostheses was similar whether the fixed (mean of 8 visits) or removable option (mean of 7 visits) was cho sen. However, the removable restoration cost less than half the price of th e fixed when both technical time and implant component costs were evaluated . Maintenance for both groups was higher than expected, but patients requir ed more appointments in the removable group both in the first year and beyo nd. Regarding the prostheses itself, the incidence of remakes, relines and general adjustments was higher in the removable group. This study has shown that the overdenture offers an effective and initially a more economical a lternative to the fixed prostheses, in the treatment of the edentulous mand ible. However, long-term maintenance of such a prosthesis can be significan t.