If bone augmentation is necessary, then sinus elevation– also called sinus lift – is used. This is a special surgical measure in jaw surgery in which the excessively thin bony floor of the maxillary sinus is thickened.
During sinus elevation, the sinus floor that holds the dental roots of the molars in the upper jaw is carefully separated from the bone via a small opening and elevated, with the cavity formed by this procedure filled with bone replacement material. The natural bone can then attach to this replacement material. This thickening process increases the bone’s volume, enabling implants to be firmly embedded.
Depending on the remaining bone substance, there are various sinus lift methods that can be used:
Internal Sinus Lift
If only a small amount of bone height needs to be added (2-3 mm), the internal sinus lift is used. In this surgical intervention, a hole is only drilled up to just under the cortical maxillary sinus floor in order to avoid injuring the maxillary sinus. Then, for the remaining length up to the implant sites, the jawbone is prepared using an osteotome (a medical instrument for separating bone), and the maxillary sinus floor (Schneider membrane) is elevated slightly in order to fill it in with bone material. The internal sinus lift is a minimally invasive procedure that causes only minor swelling.
IntraliftTM
The minimally-invasive Intralift procedure is performed using high-frequency oscillating piezo instruments (Crestal Approach Sinus Kit). They do not rotate, thereby minimizing the risk of injury for soft tissues. The Intralift procedure can be used if there is a much greater lack of bone that needs to be augmented.
External Sinus Lift
The external sinus lift is used if more than 3 mm of bone height needs to be added. This procedure is more elaborate in comparison to the internal sinus lift. To begin with, a bone window is prepared by opening up the gums and exposing the wall of the maxillary sinus. This bone window is then prepared using ultrasound instruments or fine milling instruments until the sinus floor has been reached. The sinus floor is then carefully pushed upwards in order to then fill the artificially produced cavity back up with bone replacement material.