their protruding posts for proper occlusion with the opposing arch of teeth.

In these atypical situations avoiding the canals and mental bundles as well as perforating into cortical undercuts should be the prime concern of the implantologist. Therefore many combinations for a specific case may exist. For example, insertion of some of the blades directly into the most resorbed areas of the ridge in order to avoid the canal or mental foramen may be a wise choice (4). Other times, the introduction of the specially designed socket blade into the shallower area with both of its posts resting on the more adequate alveolar bone mesial and distal to the resorbed area would be the choice (5). Insertion of a narrower blade in between the areas of bone resorbtion may also be a necessary step for some operators (6). Making grooves labio-lingually in between the areas of resorbtion (7) or even curving the groove (8) or creating a groove in a transverse-oblique direction (9) may be the most advantageous approach for a particular situation. Sometimes, but more rarely however, an asymetrically shaped groove and bladevent might have to be used (10) .

Balanced inserting is essential to keep any bladevent design from being rocked in its socket and unnecessarily destroying bone. The asymetrical shape of these implants must be compensated by atypical variations in making the socket.

When, for example, the deeper end of the blade is distal, the bone tends to be firmer than the shallow more mesial bone. To

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