Long-term evaluation of non-submerged hollow cylinder implants. Clinical and radiographic results

From 1974 various types of hollow cylinder ITI-implants were placed before the new generation of Bonefit ITI-implants was developed in the mid-eighties. The aim of this study was the clinical and radiographic evaluation of hollow cylinder implants that were inserted during the time period of 1978-1987 in partially and completely edentulous patients to support overdentures, fixed partial prostheses and single crowns. Altogether, 71 patients with a total of 132 hollow cylinder ITI-implants still in situ had been followed regularly during the entire observation period of 11.4 to 19.7 years (mean 14.1). Thirteen implants had to be removed before an observation period of 10 years was completed, 4 additional implants were lost after being in function for over 10 years and two further implants were considered to be failures at the time of the examination. Thus 91.4% of the implants were still in situ after 10 years and the survival rate for a mean observation period of 14.1 years was 84.6%. Periimplant parameters were used to assess the clinical conditions of the implants. On the radiographs, horizontal bone loss or angular defects could be detected on 40% of all implants if compared to the base-line situation. The probing depths around these implants were significantly increased compared to implants with an unchanged bone level, however the mean probing depths did not exceed 3.5 mm and 2.8 mm respectively. From this clinical evaluation one may conclude that with the early generation of hollow cylinder ITI-implants favorable long-term results were achieved.