Implant success depends on the quantity and quality of the bone the implant is placed in. Traditionally, the upper back jaw has been one of the most difficult areas to successfully place dental implants due to insufficient quantity and quality of bone.
Bone in this area tends to be less dense than in other areas of your jaw. In addition, when an upper molar is lost, your maxillary sinuses, which are behind your cheeks and above your upper molars, pneumatize, or expand downward. Maxillary sinuses are air-filled cavities that lie in close proximity to upper back teeth.
When these teeth are removed, there is often only a thin shell of bone separating the maxillary sinus and the tooth socket. When this is the case, the maxillary sinus will expand at the expense of your bone, causing a reduction in the height of available bone for implant placement.
When you loose an upper, back tooth (premolar or molar), oftentimes this results in the downward expansion of your maxillary sinus. This causes a loss of bone height and may necessitate a sinus lift prior to or at the time of implant placement.
Dental implants need bone to hold them in place. When this sinus expansion occurs, a sinus augmentation is needed to create enough vertical bone height for the implant to be surrounded in bone. Sinus augmentation (termed a sinus lift) is a surgical procedure that predictably elevates the floor of the maxillary sinus to create enough space for bone graft materials and dental implants. There are two approaches to add more bone height for dental implants, an antral (horizontal) or osteotome (vertical) sinus lift.
Antral (horizontal) Sinus Lift
Utilizing this technique, the maxillary sinus floor is entered from the place where the upper teeth used to be. A small window is made to allow visualization of the sinus membrane, which lines the maxillary sinus. The sinus membrane is then elevated upward and donor bone is inserted into the floor of the maxillary sinus. The site is then closed and sutures are placed. After several months of healing (typically 6 months), the bone becomes part of your upper jaw, creating the vertical bone height necessary for implant placement. At this stage, dental implants can be placed and will be stabilized within this new, grafted bone.
These x-rays show loss of vertical bone height following extraction of the premolar teeth on both sides of the patient’s mouth. The bone that occupied these teeth has shrunk causing reduced vertical bone dimension. In this case, there is approximately 5 mm of jawbone remaining below the maxillary sinus floor.
These x-rays show an increase in vertical bone dimension 5 months following antral sinus augmentation allowing for dental implants placement.
Osteotome sinus lift with simultaneous implant placement
When enough bone is present between the upper jaw and the floor of the maxillary sinus to stabilize a dental implant, but not enough to fully surround the implant, an osteotome sinus lift will be recommended. Typically, this procedure is completed at the same time as implant placement. Utilizing this technique, after the site is prepared for your dental implant, bone graft material is passed through this hole, lifting the floor of your sinus before the implant is placed. On an x-ray, this looks like a white dome surrounding the tip of your new implant.
Four months following extraction of the upper right second premolar, only 6.5 mm of bone height remains necessitating an osteotome sinus lift at the time of implant placement.
Osteotome sinus lift completed in conjunction with implant placement.
Implant apex completely incased in grafted bone