530 Theories and techniques of oral implantology

Fig. 11-215. The recessed shoulder of the "open socket" implant is buried close to the socket floor.

ing may not be detected if the fixed prosthesis has already been cemented over it. However, upon severing the crown covering the implant post and separating it from the rest of the bridge, the looseness becomes apparent.

Although a failing blade, just as a failing tooth, can cause considerable bone destruction, this may not be evident in radiographs. The buccal and lingual cortical plates of bone can camouflage the true condition of the medullary bone. Also, comparing immediate postoperative and current x-rays for evidence of a blade's sinking is useless because even a failing blade does not sink into bone.

Treatment

A failing blade implant must be removed. Patch-work efforts to stabilize a loose blade are not advised; the site must be cleared of all granulation tissue and invaginated epithelial tissue.

To remove the implant three incisions are made: one directly through the fibrornucosal tissues covering the superior surface of the shoulder, another along the buccal or labial surface of the blade to its entire depth, and a third along the lingual or palatal surface of the blade to its depth. The tissues are then carefully and cleanly retracted. The protruding post of the implant is firmly gripped with a wide-nosed

Fig. 11-216. A curved blade avoiding encroachment upon the open socket. If such an insertion is possible the patient need not wait several months until the socket heals for a fixed prosthesis.

pliers or extraction forceps, and the implant is worked out of the bone in a mesiodistal and occlusal direction. A crown and bridge remover may sometimes be used.

Curettes and burs are then used to remove all granulation and epithelial tissue from the groove. Only after this is done can the amount of bone destruction be accurately estimated.

Whether or not immediate reimplantation is possible depends on several factors: the width of the cleaned groove, the amount of alveolar bone remaining below the floor of the cleaned groove, and the amount of bone anterior and posterior to that groove. The occlusal level of the buccal and lingual cortical plates of bone flanking the groove should also be relatively undamaged.

Basically, immediate reimplantation is possible if another blade implant, regardless of its shape, can be set in the cleaned groove deeply enough to bury its shoulder below the floor of the original groove (Fig. 11-215). Or, a curved groove may be made around the socket to carry an appropriately bent, passively fitting blade implant (Fig. 11-216).

If too much bone and surrounding cortical plates have been destroyed, at least 4 to 5 months should elapse before attempting another implant in the same site.