Practice of engaging both the superior and inferior cortices of bone at the time of implant placement. For an edentulous anterior mandible, the tip of the implant engages the inferior cortex while the neck of the implant engages the superior cortex to maximize initial stability of the implant. The engagement of a dental implant with the crestal cortical bone of the edentulous ridge and the cortical bone of the base of the mandible or the floor of the maxillary sinus or floor of the nasal cavity. It may also apply to the engagement of the facial and lingual cortices.