Effect of surface topography of screw-shaped titanium implants in humans on clinical and radiographic parameters: a 12-year prospective study

Objectives: Although implants with a roughened surface are widely used today, little is known about the long-term effect of a roughened surface compared with the conventional machined surface on clinical and radiographic parameters. The purpose of this study is to investigate the long-term differences between moderately rough (tioblasted) titanium implants and minimally rough machined/turned surfaces with respect to marginal bone resorption and the peri-implant soft tissues in the same patient. Material and methods: In 20 fully edentulous patients, with severely resorbed mandibles, a total of 80 Astra Tech dental implants were placed in the mandible to support a bar construction with a full overdenture. In each patient two minimally rough-surfaced (turned) and two moderately rough-surfaced (tioblast) implants were placed alternately. Clinical evaluation was carried out at base line (prosthetic installation), 6 months, 1, 2, 3, 4, 5 and 12 years. Radiographic evaluation using standardized individual filmholders was carried out at base line (prosthetic installation), 6 months, 1, 5 and 12 years. Results: In two patients, during the abutment surgery, one turned implant showed insufficient osseointegration and was replaced. One implant showed an abutment fracture after 9 years and was kept as a sleeper. From base line up to 12 years, no implant was lost. No significant differences were found between both implant surfaces concerning the clinical parameters such as plaque, calculus, bleeding and probing pocket depth. The mean (SD) marginal bone changes up to 12 years varied between -0.11 and +0.01 mm for the turned and −0.2 and +0.01 mm for the tioblast implants. No significant difference in marginal bone loss was found between both implant surfaces. Conclusion: We conclude that after 12 years of follow-up, no differences could be found between the turned and the tioblasted implants, both for soft and for hard tissue parameters