A COMPARATIVE CLINICAL-STUDY OF 3 DIFFERENT ENDOSSEOUS IMPLANTS IN EDENTULOUS MANDIBLES

The purpose of this prospective study was to investigate the clinical outcome and marginal bone resorption of three different endosseous imp lants placed in the anterior mandibles of 15 elderly patients. Eleven women and 4 men (ranging from 65 to 80 years, mean 71 years) had three different endosseous implants placed in the anterior mandible; one ti tanium plasma-sprayed cylinder implant (4-mm diameter), one titanium c ylinder implant with hydroxyapatite coating (4-mm diameter), and one s tandard threaded titanium implant (3.75-mm diameter). Three months lat er, at the second-stage surgical procedure, ball abutments were connec ted and an overdenture was placed. At 12, 24, and 36 months, marginal bone resorption and Periotest values were recorded. None of the implan ts was lost in this period. An analysis of valiance with repeated meas urement was performed annually to test the existence of significant di fferences between the implants. When differences appeared, paired t te sts were used to identify which differences were significant. Bonferro ni multipliers were used to adjust for multiple testing. When marginal bone resorption was concerned, threaded titanium and hydroxyapatite-c oated implants had significantly better scores than titanium plasma-sp rayed cylinder implants. Periotest values for hydroxyapatite-coated im plants were significantly better than test values for the other implan ts after 2 years. After 3 years significance was obtained between hpdr oxyapatite and screw-shaped implants only (P <.05). It was concluded t hat titanium plasma-sprayed cylinder implants have a less favorable pr ognosis than the other implants used in this study.