This study1 evaluated soft tissue outcomes of 33 previously reported (Thoma et al. 2014) patients who received tissue-level Straumann implants or bone-level Nobel Biocare Brånemark System implants restored with single crowns (SCs) or fixed-partial prostheses (FDPs).
Patients in the tissue-level implant group were restored with 11 SCs and 4 FDPs whereas those in the bone-level implant group were restored with 14 SCs and 4 FDPs. Tissue thickness, crown height, and facial tissue volume changed very little at the 1-year follow-up, and without significant differences between the two groups.
The bone-level group had smaller changes in crown height (0.02 ± 0.32 mm vs. −0.17 ± 0.58 mm), but lost slightly more volume over time (−0.12 ± 0.27 mm vs. −0.03 ± 0.29 mm) and exhibited more pronounced changes in tissue thickness at the 1 mm level (−0.15 ± 0.20 mm vs. −0.03 ± 0.35 mm).
Although a clinically small difference (–0.08 ± 0.20 mm vs. –0.35 ± 0.35 mm), patients restored with Brånemark System implants experienced significantly less bone loss (p<0.01).
As a prospective randomized study, the original report provides high-level evidence that early failure rates are low with both implants.