Block allografts can serve as effective alternatives to block autografts but are more brittle and can easily break if not properly contoured to fit the defect site. The need to make such preparations during surgery can prolong the invasive procedure and may result in a less-than-optimum graft preparation that can compromise success. The sterile 3D block technique allows block allografts to be prepared and attached to a stereolithography model of the patient's jaw prior to surgery and then stored in a sterile environment until surgical delivery. Keywords: allografts, bone grafts, corticocancellous bone, stereolithographic models