Figure 3: (a) Preoperative view of 46 showing Grade - 3 furcation involvement, (b) preoperative intra-oral periapical radiograph revealing through and through bone loss in the furcation region, (c) full-thickness mucoperiosteal flaps reflected and furcation region exposed, (d) 3 months postoperative view showing the tunnel interdentally, (e) interdental brush being passed through the tunnel created surgically