and 2. Figure 1. Epifluorescent micrograph (×100) of screw-supporting bone in the maxillary posterior region. Note the periosteal (top) and endosteal callus, both of which have incorporated the calcein bone label. The intracortical passage is spanned by 1 pitch of the screw. Figure 2. Epifluorescent micrograph (×40) of screw-supporting bone in the mandibular mid region. Osteonal remodeling typical of bone healing is evident. Modeling response of the periosteal and endosteal callus is very limited. The intracortical passage is spanned by 3 pitches of the screw. Intimate bone adaptation is seen at 6 weeks postinsertion