Guided Bone Regeneration of a Seibert Class III Bone Defect With Bioactive Calcium Phosphosilicate Bone Graft: Human Histology and Clinical Report Guided Bone Regeneration of a Seibert Class III Bone Defect With Bioactive Calcium Phosphosilicate Bone Graft: Human Histology and Clinical Report Filipe F. Lopes, DMD, DDS Maurice Salama, DDS