The bur is then slightly retracted (16) to back its shank out of the bone, and then run along the ridge, making the major portion (17) of the socket and firmly establishing its direction in one sweep. One more pass of the bur, initiated at the original insertion site, is usually adequate to complete the socket. The fingers (18) are kept on the ridge to sense the bur's progress.

Caution: Progress the bur evenly (19). Do not drag or advance (20) its tip. This will distort the socket's shape and very likely perforate the labial plate.

Caution: Running the bur back and forth in a narrow ridge, trying to gradually create the socket, increases the opportunity of over-enlarging the channel or fracturing or perforating the bone. Caution: Whereas a shallow socket may be preferable in a wide fragile ridge, a completely drilled socket is essential in a narrow situation. The deep socket gives greater control over final seating of the implant, and prevents overspreading or fracturing the ridge.

When bending the blade to follow the groove, avoid tipping the implant into and out of the socket to see if it "fits." Bending may fracture the crest, and it may not be possible to deepen the socket below the fracture.

If fingers obscure the view of the operative site, use a carrying instrument (21) to compare the blade to its groove.

The correctly bent blade is inserted, and the angle of its post checked with those of other abutments. It is removed, and pliers are used to bend the neck of its post to the correct angle. Again, try to establish the correct angle the first time out of the mouth. Avoid replacing and removing the blade. A slip in the angle of insertion or retraction is hazardous in a knife-edge ridge.

The prepared socket is checked for obstructions and gently cleaned. The implant is replaced and ready to be tapped home.

Final seating is cautiously executed in a narrow ridge situation. Even with fingers bracing the bone, off-center or unbalanced tapping can break the thin, fragile wall of the socket. The pointed (shoulder-set) seating instrument is inadvisable for the first few taps because it can slip easily and chip the ridge. Therefore, an atypical procedure is followed — bending the post is delayed. The single-head seating instrument is used on the unbent post to tap the implant almost completely to its proper depth. Then the imlant is removed, its neck bent, and the implant is replaced. It is now seated deeper and is firmly held by bone. Thus secured, the shoulder-set point instrument (22) can be used to tap the implant home.

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