The invention comprises various materials and methods for the formation of bone within a patient using implanted bodies that are seeded with bone forming cells. The implants of the invention may comprise interlocking building blocks which allow for the formation of any desired structure. The geometry of the resulting bone structure can be tailored with great precision, and can be controllably integrated with native bone as desired. Advantageously, the methods result in the formation of functional, structured bone and avoid overgrowth, undergrowth, and the use of growth factors such as BMP-2.