An open, randomised, multi-centre study, comparing straight and tapered apex implants design, in partially and...

The design of the commercially available implant OsseoSpeed^® (control) was changed to a tapered apex with a smaller apical diameter; OsseoSpeed^® TX (test).

The present study evaluated the clinical outcome of marginal bone level as primary outcome, and cumulative implant survival rate, primary stability and condition of the peri-implant mucosa as secondary outcomes, one year after loading.

92 subjects (150 implants, ten centres), with partially or totally edentate maxillae were randomized to receive either test or control implants. One to six implants were placed in each subject using a one-stage surgical procedure. Subjects received a permanent prosthesis 10-12 weeks after implant placement and were followed for one year.

47 subjects in the test group received 82 implants and 45 subjects in the control group received 68 implants. Marginal bone level alterations from loading to 1-year follow-up was -0.02 × 0.41 mm (mean × SD) and -0.03 × 0.38 mm (mean × SD) for the test and the control group, respectively, indicating no difference between the groups. Non-inferiority was declared as confidence interval for the difference between control and test implants was no worse than 0.5 mm. The CSR was 98.8% in the test group and 100% in the control group, with no statistically significant difference between the groups.

Change of the apical design of a commercially available implant showed no significant effect on marginal bone level and CSR compared to the control implant. Missing data and many investigators may have influenced on the result. Trial registration number: NCT01324778.