In Single Tooth Implant Case:
a) Vertical distance available between the crest of residual ridge to the opposing occlusal surface. At least 7 mm space is required to a cementable prosthesis. If the space is lesser, then a screw retained prosthesis or use of UCLA type of abutment will be required.
b) Mesiodistal space, the diameter of the implant to be used not only depends on the buccolingual width of the residual ridge but also on the mesiodistal space. The mesiodistal span should be measured and then the available bone is calculated after deleting 1.5-2mm from to the base of both the adjacent natural teeth.
c) The buccolingual ridge contour should be carefully studied to reveal the presence of undercuts. The objective way is to measure on the multiplanar reformatted images of a Dentascan. However, a ridge mapping procedure can also be done. Another cast of the patient is split buccolingually using a hand die cutting saw or mechanical saw at the prospective site of implant placement.