BACKGROUND:Advanced platelet-rich fibrin (A-PRF) is an autogenous blood product with applications in dento-alveolar surgery. However, there is minimal information regarding its optimal clinical application or efficacy. The aim of this multi-arm parallel randomized controlled clinical trial was to evaluate the efficacy of A-PRF alone or with freeze-dried bone allograft (FDBA) in improving vital bone formation and alveolar dimensional stability during ridge preservation. METHODS:Forty patients requiring extraction of non-molar teeth and replacement with dental implants were randomized into one of four ridge preservation approaches: A-PRF, A-PRF+FDBA, FDBA, or blood clot. A-PRF was prepared at 1,300 rpm for 8 minutes. Non-traumatic extractions and ridge preservation was performed. After an average of 15 weeks healing, bone core samples were harvested at the time of implant placement for micro-CT and histomorphometric analysis. Ridge dimensions were measured immediately after extraction and before implant placement. RESULTS:Significantly greater loss of ridge height was noted in the blood clot group (3.8 ± 2.0 mm) compared to A-PRF (1.8 ± 2.1 mm) and A-PRF+FDBA (1.0 ± 2.3 mm) groups (P < 0.05). No significant differences in ridge width reduction were noted between groups. Significantly more vital bone was present in the A-PRF group (46% ± 18%) compared to the FDBA group (29% ± 14%) (P < 0.05). Bone mineral density was significantly greater in the FDBA group (551 ± 58 mg/cm3 ) compared to blood clot (487 ± 64 mg/cm3 ) (P < 0.05). CONCLUSIONS:This study demonstrates A-PRF alone or augmented with FDBA is a suitable biomaterial for ridge preservation. This study represents the first randomized controlled clinical trial comparing A-PRF with and without FDBA to FDBA alone for ridge preservation.

The fundamental goal of a rare plant translocation is to create self-sustaining populations with the evolutionary resilience to persist in the long term. Yet, most plant translocation syntheses focus on a few factors influencing short-term benchmarks of success (e.g., survival and reproduction). Short-term benchmarks can be misleading when trying to infer future growth and viability because the factors that promote establishment may differ from those required for long-term persistence. We assembled a large (n = 275) and broadly representative data set of well-documented and monitored (7.9 years on average) at-risk plant translocations to identify the most important site attributes, management techniques, and species' traits for six life-cycle benchmarks and population metrics of translocation success. We used the random forest algorithm to quantify the relative importance of 29 predictor variables for each metric of success. Drivers of translocation outcomes varied across time frames and success metrics. Management techniques had the greatest relative influence on the attainment of life-cycle benchmarks and short-term population trends, whereas site attributes and species' traits were more important for population persistence and long-term trends. Specifically, large founder sizes increased the potential for reproduction and recruitment into the next generation, whereas declining habitat quality and the outplanting of species with low seed production led to increased extinction risks and a reduction in potential reproductive output in the long-term, respectively. We also detected novel interactions between some of the most important drivers, such as an increased probability of next-generation recruitment in species with greater seed production rates, but only when coupled with large founder sizes. Because most significant barriers to plant translocation success can be overcome by improving techniques or resolving site-level issues through early intervention and management, we suggest that by combining long-term monitoring with adaptive management, translocation programs can enhance the prospects of achieving long-term success.