The amount of viable bone in a composite graft that consisted of autogenous iliac bone marrow, allogenic rib, and porous hydroxyapatite was quantified using standard histologic techniques and an optical insert disk prior to placement of endosteal implants in an augmented mandible. It is suggested that this technique could be used in such cases before deciding whether to proceed with implant insertion. Palabras clave: atrophic mandible, bone quantification, composite graft, endosteal implants, porous hydroxyapatite