Marginal bone loss at implants with different surface characteristics - A 20-year follow-up of a randomized controlled clinical trial.

OBJECTIVE: This report is a 20-year follow-up of a randomized controlled clinical trial evaluating the potential long-term effect of a modified implant surface on the preservation of the peri-implant marginal bone level. MATERIAL & METHODS: In each of 51 patients and for each fixed partial denture (FPD), by randomization at least one implant installed had a non-modified turned surface and one a modified and roughened surface (TiOblast((R)) ). Clinical and radiological examinations were performed at various follow-up intervals. Primary outcome variables were peri-implant marginal bone level change from time of loading and proportion of implants with no bone loss at 20 years. Multilevel analysis followed by nonparametric and Pearson's Chi-Square tests were applied for statistical analysis. RESULTS: At the 20-year follow-up, 25 patients carrying 64 implants were available for evaluation. Turned and TiOblast implants presented with a mean bone level change from the time of FDP delivery amounting to -0.41 mm (95% CI -0.84/0.02) and -0.83 mm (95% CI -1.38/-0.28) respectively (inter-group comparison p > .05). 47% of the Turned and 34% TiOblast implants (p > .05) showed no bone loss. All but one of these implants were free of bacterial plaque and inflammation as well as presented with probing pocket depths </=5 mm at both the 5- and 20-year follow-up examinations. CONCLUSION: It is suggested that a moderate increase of implant surface roughness has no beneficial effect on long-term preservation of the peri-implant marginal bone level.