After the desired depth and diameter of the recipient site is accomplished, the implant is placed. For titaniumimplants, an uncontaminated surface oxide layer is necessary to obtain osseointegration. Contamination, by
touching the implant with instruments made of a dissimilar metal or by contact with cloth, soft tissue, or even surgical gloves may affect the degree of osseointegration. HA-coated implants are also sensitive to contamination. HA is porous and will easily absorb liquids or oils and
become contam inated with fibers from cloth drapes or
powder from surgical gloves. Nonthreaded implants are positioned into the recipient site and gently tapped into place with a mallet and seating instrument (Fig. 14′-50). Threaded implants are screwed into place, which requires an additional step to place the screw threads into the recipient site bone (Fig. 14-51). Threading the bone is done at very low speeds (e.g., 15 rprn), Self-tapping implants are available from most implant systems. However, in very dense bone, threcipient site should still be tapped to produce threads avoid excess torque during implant placement. Exces
torque can damage the antirotational features of the implant, may crush the bone leading to necrosis, or may eveninduce fractures. After allImplants are placed, the wound is closed. A tension-free closure is important to prevent wound dehiscence. Horizontal mattress closure with monofilament
suture will produce a watertight.closure.