When performing sinus augmentation, accurate radiography is the clinician’s best guide. We must know the exact location of the floor of the sinus to determine how high up to begin the window. We also want to know the mesial and distal extents of the sinus in order to plan how far forward and how far back to treat. In addition, knowing the thickness and density of the lateral wall of bone helps us avoid a perforation of the sinus membrane. It can be misleading if the lateral wall of bone is fairly dense; a 2- or 3-mm thick dense wall of bone over the sinus on the facial aspect can lead the dentist to believe that a certain area has been reached, when in fact it has not. The CBCT scan offers precision with a clearer understanding of the surgical site (where you should be, or not be), and what to expect as you remove lateral wall bone.
The scan also clearly demonstrates any septa within the sinus. In cases where a septum completely divides the sinus, 2 windows must be created, essentially resulting in 2 separate procedures on the same antrum. Other times, with a partial septum, much care must be taken in elevating along the floor of the sinus to ensure that the schneiderian membrane does not get torn at that point.
CB scans give a dentist confidence in implant placement, and the fact that these machines are readily available is a great step forward. In addition, piezosurgery, along with proper technique, gives us the ability to cut hard tissue without damaging soft tissue,5 reducing the serious perforation rate from 30% (found with rotary instrumentation) to 7%, or less
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