the blade—from leading edge (2) , to post bottom (3) —tall enough to fall just short of the canal (4). This provides two abutments in a single surgical site, and in prosthodontically desirable locations: the second bicuspid and the second molar.

The groove is made slightly lingual to the crest (5), and wherever possible is made vertical to the horizontal plane (6) . In a good ridge, the groove should not threaten the inferior alveolar nerve or mental bundle (7).

In some posterior areas, if the bone is porous, drilling a socket whose depth is less (8) than the bladevent measures from the bottom of its post to its leading edge (9) might be desirable. The legs of the bladevent will break the few remaining bony bridges as the implant is tapped to its proper depth.

The groove is made slightly longer mesio-distally (10) than the length of the blade. Distally, it begins about 2 mm to 4 mm distal to the mental foramen (11) to avoid intruding beyond the posterior limits of the body of the mandible. In addition to providing a safety margin, the 2-4 mm limit helps position the implant far enough forward so that its posterior post will not interfere with the angle of the jaw where the bone sometimes is porous due to the storing up of hematopoetic marrow in the area, the enlargement of the canal and the area and deep submandibular fossaes that may exist. Also, the distal post of a double- or triple-posted blade will usually be in loose alveolar tissue rather than attached gingivale (12) .

The bladevent is bent to fit passively within the groove, tried in it, and the proper alignment of the posts estimated. The bladevent is withdrawn, and the neck bent to parallel the posts with the other abutments and perpendicular to the dental arch.

Caution: When bending the neck, grasp with the pliers only that portion of the bladevent's body directly under the post (13). Clamping the entire body (14) will straighten the carefully curved implant.

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