and the implant must be angled (19) to avoid impinging upon their periodontia. The implant socket may also be angled to avoid a flaw (20) in the ridge.

The 700 XXL bur is used to make the socket for this long implant. In particularly dense bone—which is usually seen in the ca-nine area or in the symphyseal region (21)—more than one fresh bur may be needed. Some bone is so dense that reducing the implant's height (22) is preferable to intense, high-friction drilling. When the bone is very porous, a few millimeters should be left to be broken by the implant's legs as the implant is finally seated.

The teeth bordering the edentulous span may interfere with the head of the contra-angle, preventing the bur from reaching the desired depth (23). The bur can be locked further out of the contra-angle head; the standard contra-angle can be replaced with a pedo-headed contra-angle; or a straight handpiece (24) can be used to go between the teeth with a special bur to fit it. If neighboring teeth are to be prepared for full crowns, this can be done prior to starting the implant socket to make easier access for the implant groove.

Usually the bone between the crest of the ridge and the inferior floor of the symphyseal area is deep enough to accept the manufactured size of a single-tooth implant. However, excessive resorption, or reduction of a knife-edge ridge to make it better accommodate an implant, may make the ridge shorter than the implant (25). The implant can be shortened by cutting (22) a few milli-meters off the legs. The altered legs should be retapered and smoothed (26).

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