Degree three furcation is classified as horizontal "through and through"destruction of the periodontal tissue in the furcation. Treatment of Grade 3 furcation has historically been less than predictable. This is due to anatomic complexity and irregularity which increases susceptibility to bacterial retention and impedes accessibility for oral hygiene and periodontal debridement.The management of furcation defects in recent years shifted away from a resective approach to a regenerative one.This book is an attempt to present all treatment modalities in the management of grade 3 furcation involvement along with various complications faced in management of grade 3 furcation involved molars.