Wen SC, et al. - In this investigation, researchers histologically assessed and compared vital bone formation, residual graft particles, and fraction of connective tissue (CT)/other tissues between three different time points at 2-month intervals after alveolar ridge preservation with a cancellous allograft and dense – polytetrafluoroethylene (d-PTFE) membrane. A statistically significant difference was found in the amount of vital bone at every time point from 28.31% to 40.87% to 64.11%. This investigation provided a first histological comparison of alveolar ridge preservation at three different time points using a cancellous allograft and d-PTFE membrane. Extraction sockets healed for 6 months produced the highest amount of vital bone combined with the lowest percentage of residual graft particles, while similar outcomes were noted for the CT/other tissue fraction between the 3 time points.