Implant site evaluation
1. Ridge:
Total buccolingual width of the ridge- the thickness of the soft tissue ( bucally +lingually)= Buccolingual width of the bone. There should be at least 1mm thick layer of bone present on both the lingual and buccal aspects of the implant diameter that has been selected for placement.
2. Mesio-Distal Distance:
The implant diameter, implant type, position, and the number of implants are selected according to the anatomy and space available. Initially the width of the gap is calculated. The width of the gap depends upon the tooth shape. Generally it is 1.0mm (2 × 0.5 mm) shorter than the bone level. Mesio-distally there should be a distance of 1.5-2.0mm from the impression shoulder to the adjacent tooth at the bone level. Like for e.g. The minimum gap width for a 4.2 mm implant is
4.2 + 2 × 1.5mm = 7.2mm.