With the publication of our technique of removing the sinus membrane during sinus augmentation, we experienced a flood of orders for Sinus Graft. Our previous emails were focused on the success and predictability of the technique, but were not focused on the fine points of the surgery. To help our new customers be successful with the technique, we have compiled a “How to” article to help your decision-making process for what many are calling a game changer for sinus augmentation.
Crestal Approach or Lateral Approach
A CT scan is beneficial to understand the 3-dimensional morphology of the graft site, but it is not necessary to perform this surgery.
The primary decision for this method is if you will use the implant osteotomy to remove the membrane and graft or if you will use a small lateral wall osteotomy to remove the membrane and graft. The preferred choice for surgical expediency is to use the implant osteotomy. However, the decision to use the lateral wall or the crest for your access to the sinus is decided by the amount of bone between the crest and the sinus. If there is 4 mm or less of crestal bone, we recommend using the implant osteotomy to remove the membrane and graft the sinus. If there is more than 4 mm of crestal bone, we recommend using the lateral wall. The reason is because when you are working in bone deeper than 4 mm, it is difficult to get the instruments into the sinus, pivot the instrument around the sinus, and confidently remove the membrane. Likewise, it is difficult to get the tip of the bone graft syringe into a deeper osteotomy and predictably inject the graft material on the floor of the sinus. When using the small lateral wall osteotomy, it is easy to remove the membrane from the floor of the sinus and easy to inject the graft material onto the floor of the sinus.
Due to the ease of instrument manipulation, we advise those new to the technique to use the lateral wall method. The sinus membrane is very delicate and there is no need to vigorously scrape the sinus wall. There is no need to remove any bone and no need to create bleeding. If you create any bleeding, you are scraping too excessively.
If using the lateral wall method, make crestal incisions in the gingiva and on the buccal, carrying the incisions around the mesial of the anterior tooth. Make a vertical incision on the distal line angle of the tooth anterior to the tooth adjacent to where the implant will be placed. Raise the flap to gain access to the lateral wall of the sinus. No distal vertical incision is usually needed. Do not raise the lingual flap until you have grafted and you need to start your implant osteotomy. This is to prevent bleeding into the patients mouth while working on the buccal. The reason for carrying the vertical incision further away from the lateral wall osteotomy is so you do not have a vertical incision near the lateral osteotomy. The small osteotomy will heal spontaneously and will not need a membrane. After you have made your flap, mix Sinus Graft. You will need to let the graft activate for about 3 minutes before use, but as long as the graft is in the syringe, it will not set even though it is mixed. Use sterile gauze to pick up the syringe tip so no bacteria is carried into the sinus.
When locating where to place the lateral wall osteotomy, simply measure the amount of bone between the crest and sinus and add a few more millimeters above the radiographic location for the floor of the sinus. Because you are going to remove the sinus membrane, simply drill through the lateral wall and into the sinus with a large round bur. Enlarge the osteotomy to approximately 4 mm. Once into the sinus, it is good to get a feeling for the difference between the feel of the sinus membrane and bone. Use a blunt instrument (probe or ball burnisher) to enter the sinus and you will note that the membrane has a velvet feel to it. This will help you know that the membrane is removed because bone will have a grainy feel to it. Once you are into the sinus, either through the implant osteotomy or a lateral osteotomy, we start our membrane removal with an angled curette and finish with a hoe such as a 13K. We use these instruments simply because they are always on our surgical tray. If there are any enterprising dentists reading this: custom designed curettes for sinus membrane removal could be an advantage.
Estimate the amount of bone you need to produce on the floor of the sinus and remove the membrane to at least this distance. The bone graft will bond to bone, but not to the sinus membrane. Where you have membrane, you will not get bone growth.
If you are doing a lateral wall approach, lay the lingual flap and prepare your osteotomy for the implant after you have grafted the sinus. If there has been significant time lapse since placing the graft, possibly due to placing multiple implants, you will want to prepare your implant osteotomy to the full length of the implant. The graft may have hardened and placing an implant into hardened graft can lift the graft off the floor of the sinus. Sinus Graft sets in about 30 minutes once applied into the sinus.
Let’s look at some cases that explore these points.
