Extraction defects had healed by 12 weeks postoperative. Remnants of the poly(propylene glycol-co-fumaric acid) (PPF) scaffold (examples are marked with an asterisk) were observed to be surrounding by newly formed bone (marked with black arrows) in (A) nanometer-hydroxyapatite (HA)-augmented PPF and (B) micrometer-HA-augmented PPF materials. Defects filled with (C) demineralized freeze-dried human bone allograft were filled with new bone, whereas bone recovery was still occurring in (D) untreated defects