Long-term follow-up of turned single implants placed in periodontally healthy patients after 16–22 years: radiographic and peri-implant outcome

Objectives: Retrospectively evaluate the survival, radiographic and peri-implant outcome of single turned Bra degrees nemark (TM) implants after at least 16 years. Materials and methods: From 134 patients (C-group), 101 could be contacted concerning implant survival and 50 (59 remaining implants) were clinically examined (I-group). Marginal bone level was radiographically measured from the implant-abutment junction at baseline (within 6 months after abutment connection) and 1-4, 5-8 and 16-22 years post-operatively. Probing depth, gingival and plaque index weremeasured. Marginal bone-level changes were analyzed using Friedman's andWilcoxon's signed ranks tests. Spearman's correlations between radiographic and clinical parameters were calculated. Results: In the C-group, 13 out of 166 implants in 11 out of 134 patients failed (CSR 91.5%). In the I-group (28 males-22 females; mean age 23.9 years at baseline; range 14-57), the mean follow-up was 18.4 years (range 16-22). Themean bone levelwas 1.7 +/- 0.88mm (range = 0.8 to 5) after 16-22 years. Changes in the meanmarginal bone levelwere statistically significant between baseline and the second measuring interval (1-4 years). Thereafter, no significant differences could be demonstrated. The mean interproximal probing depth, gingival and plaque indices were 3.9 +/- 1.27mm, 1.2 +/- 0.81 and 0.2 +/- 0.48, respectively. Probing depth was moderately correlated with gingival inflammation (r = 0.6; P0.05). 81.4% of the implants had a bone level <= 2nd thread and 91.5% had a probing depth <= 5mm. 76.3% had both bone level <= 2nd thread and probing depth <= 5mm. Conclusions and clinical implications: The single turned Branemark (TM) implant is a predictable solution with high clinical survival and success rates. In general, a steady-state bone level can be expected over decades, with minimal signs of peri-implant disease. A minority (5%), however, presents with progressive bone loss