rounded instrument and using a #6 round bur in a contra-angle with a sufficient water spray, channels the bone along the existing mandibular canal floor to deepen it several mms (2) .

The depth of the floor is dependent upon the total amount of bone in the body of the mandible. If the canal is channeled too deep it could cause a mechanical fracture. With a #557 fissure bur, a vertical groove is made from the most superior portion of the cortical plate, in the area where the original foramen existed to about two or three mm inferiorly (3). With a #4 or #6 round bur, at the base of the vertical groove, a round keyhole style window is cut into the buccal cortex (4). The mental nerve is carefully stretched with the thumb and forefinger of each hand, so that it can slip through the narrower vertical groove and then left to exit out of the larger round window representing the mental foramen (5). Soft wax is placed over the entire length of the artificial mandibular canal so that an impression can be taken with-out involving the underlying nerve (6). The subperiosteal implant is designed uniquely, so that there are no secondary struts crossing over the exposed mandibular nerve (7). Healing is often uneventful and many cases have been done in this manner (8). However, if the patient did not already complain of a paresthesia due to pressure from the original conventional denture pressing on the exposed nerves, a warning should be given to them over the possibility of a paresthesia, that could be brought about from the hand-ling of the nerve bundles during this operation.