Fig. 6 Micro-CT results. a Only a dental implant fixture was implanted (implant group); b A composite of the β-TCP microspheres and the hyaluronic acid powder gel was injected and a dental implant fixture was inserted (hydrogel group); c A composite of the rhBMP-2 loaded β-TCP microspheres and the hyaluronic acid powder gel was injected and a dental implant fixture was inserted (BMP-2 group). In panel a, new bone formation was insignificant around the implant fixture but some new bone was shown in panel b, while extensive new bone formation was observed in panel c (arrows: newly formed bony tissue)