ABSTRACT
The weak point of the whole procedure relies on the accuracy in the transfer of information deriving from CT data into surgical planning. Geometrical deviations of implant positions between planning
and intervention stages, could cause irreversible damages of anatomical structure, such as sensory nerves. The surgical guide should be a digital duplicate of the radiographic guide especially for what concerns the part fitting the soft tissues. If the surgical template is not accurate, the fit will be improper and the surgical guide will be pinned in the wrong position, compromising the implant placement. Even small angular errors in the placement of perforation guides can, indeed, propagate in considerable horizontal deviations due to the depth of the implant (10 ÷ 15 mm).
