Background

Recombinant human bone morphogenetic protein-2 (rhBMP-2), which is a potent osteoinductor, has long been considered a promising avenue for bone regeneration, and has been commercially available for the treatment of oral and maxillofacial hard-tissue defects. RhBMP-2-soaked bone graft materials have generally been used in sinus floor augmentation and extraction socket preservation.

Aim/Hypothesis 
 The aim of this study was to evaluate the safety and effect of two types of rhBMP-2-soaked bone graft materials on extraction socket preservation.

Materials and Methods 
Between October 2015 and September 2016, bone graft was performed in 64 patients scheduled to receive implantation after single tooth extraction. O-BMP (Osstem Implant Co., Busan, Korea; scaffold: collagen sponge) and Cowell BMP (Cowellimedi, Busan, Korea; scaffold: ß-TCP) were used. The experimental group (n=32) received O-BMP grafts, and the control group (n=32) received Cowell BMP grafts. After covering the resorbable collagen membrane, the flap was closed. Before and 12 weeks after the operation, cone-beam computed tomography (CBCT) was used to assess the changes in bone height, and the widths at 25%, 50%, and 75% of the extraction socket levels. To match the axis of the measurement sites on CBCT images for the same patient, the patients underwent scans while wearing customized stents with a radiopaque indicator. Patients who agreed to undergo biopsy were evaluated for histological healing by obtaining tissue specimens with a trephine bur at the time of implant placement.

Results (
The experimental and control groups showed good healing without specific complications, such as infection. CBCT evaluation of the width and height change of the extraction socket revealed that the amount of bone resorption in the experimental and control groups was not large and that the shape of the extraction socket was well maintained. The mean changes in bone height and bone width at 25%, 50%, and 75% of the extraction socket levels were -0.08 ± 0.90 mm, 1.15 ± 5.01 mm, 1.19 ± 4.75 mm, and 0.20 ± 1.42 mm, respectively, in the O-BMP group, and -0.68 ± 1.42 mm, 0.57 ±4.41 mm, 0.68 ± 3.47 mm, and -0.26 ± 2.58 mm, respectively, in the
Cowell BMP group. The bone height change of O-BMP group showed lower than that of the Cowell BMP group(p<0.01). However, no statistically significant intergroup differences were observed in the changes in the width(p<0.05). Histological examination showed good healing without inflammatory reaction, and new bone formation increased with time.

Conclusions and Clinical implications 
Compared with Cowell BMP®, which has been proven effective and safe, O-BMP used in extraction socket preservation resulted in clinically and histologically better healing and preservation.

Evaluation of the efficacy and safety of two types of rhBMP-2-soaked bone graft materials in extraction socket preservation