closed over the underlying bone.

It becomes extremely important to remove the labial and buccal crest undercuts that often exist in extreme knife-edge ridges so that a continuous groove can be made to its proper depth with-out perforating the labial cortex.

Whereas it often becomes necessary to remove tori when den-

tures are anticipated, it is absolutely unnecessary with blades. Highly attached frenums, or scar tissue that prevent normal

movements of the lips should be reduced prior to implant surgery. Any excess hyperplasia should be removed.

Hyperplastic labial mucosal tissue (double-lip) from an ill fitting denture must be incised and removed prior to implant surgery.

A partial thickness flap is never done when inserting implants since they must all be beneath the mucoperiosteal tissues. A partial thickness flap is used when tissue grafts become necessary or it is necessary to reduce the tissue thickness.

In the region of the maxillary tuberosities where often the tissues are ten to fourteen mm. thick and even wider bucco-lingually it often becomes necessary to thin them out by degloving. Also, it is sometimes necessary when the excessive thickness in the area will interfere with a proper centric occlusion, especially when an implant post was inserted in a socket but was totally buried by thickened tissues. It is more desirable to lengthen the post by telescoping it rather than reducing the tissue.

Deepening the vestibular sulci in excessively flat ridges which is so often necessary for obtaining some sort of retention with conventional dentures presents very little problem when contemplating implants. Only when the muscle attachments fall directly beneath the implant posts or remaining teeth is it necessary to reduce the sulci.

Sometimes in an extremely wide mandible you can often circumvent rather than drill directly through one or two open sockets in order to immediately gain a maximum amount of the metal of the implant to the available bone.

By incising directly to the bony crest, the residual gingiva is not destroyed. Gingiva is destroyed when too much of the bone is resorbed.

In conditions when very little or no attached gingiva remains over the ridge and an implant is inserted, a tight attachment of the tissue around the post is not attained and either it will be necessary

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