A key to success of a dental implant is the quantity and quality of the bone where the implant is to be placed. The upper back jaw has traditionally been one of the most difficult areas to successfully place dental implants due to insufficient bone quantity and quality and the close proximity to the sinus. If you’ve lost bone in that area due to reasons such as periodontal disease or tooth loss, you may be left without enough bone to place implants and a sinus augmentation can raise the sinus floor to allow for new bone formation.
In the most common sinus augmentation technique, a tiny incision is made near the upper premolar or molar region to expose the jawbone. A small opening is cut into the bone and the membrane lining the sinus on the other side of the opening is gently pushed upward. The underlying space is filled with bone graft material and the incision is closed. The bone which is used for this procedure may be from your own body or from a cadaver. Sometimes the dentist might use synthetic materials which can also stimulate bone formation. The implants are placed after healing has occurred; this will depend on the individual case. Sinus augmentation has been shown to increase the success of dental implant procedures.
Common Reasons for Having Sinus Lift Surgery
Sinus lift surgery is used in cases where the upper jawbone height is insufficient or the sinuses are too close to the jaw to place dental implants. Jawbone anatomy is such that the upper jaw naturally has less bone than the lower jaw. Some sinus lift patients simply have a smaller jawbone while others have jawbone loss. Sinus augmentation provides a strong bony foundation by bone grafting for dental implants.
Factors which can contribute to jawbone loss include:
- Tooth loss: Extraction or missing teeth eventually lead to bone resorption (absorption back into the body) if the space is left vacant.
- Periodontal disease: Gum disease can cause bone loss if left untreated.
- Oral pathology: Cysts or tumors can damage the jawbone.
A toothless, or edentulous, area is known as a ridge. The collapse of the tooth socket, together with an expansion of the maxillary sinus floor (which occurs when a molar is lost), causes the jawbone to thin out, resulting in less volume available for the dental implant.
Physiological factors which can necessitate sinus lift surgery include:
- Small jaw
- Location of the sinuses, blood vessels, and nerves
- Large sinus (can enlarge with age)
- Proximity of adjacent teeth roots
Types of Sinus Lift Surgery
Sinus lift surgery is an in-office procedure which is typically performed with local anesthesia or IV sedation. In more complex cases, general anesthesia may be employed. During sinus lift surgery, the sinus is raised and a bone graft is performed to allow for eventual osseointegration, the process in which the regenerated bone connects with the prosthetic implant. Several techniques are available to perform the sinus lift procedure.
Lateral Window Technique (Direct Sinus Lift Procedure)
Lateral window technique is considered the traditional sinus augmentation surgery during which the oral surgeon makes an incision in the gum, exposing the bone. A window is made into the sinus and the piece of bone cut out is pushed into the sinus cavity. The bone graft is placed in the space underneath.
The incision is sutured closed, leaving the bone graft to heal for 4-6 months. In some circumstances, the implant is actually placed at the time of the sinus lift procedure.
Osteotome Technique (Indirect Sinus Lift Procedure)
The osteotome technique is a less invasive sinus lift surgery that can be utilized when over 6mm of natural bone height is present and the sinus floor requires less than 4mm of elevation. A flap of gum tissue is cut to form a socket in the bone. An osteotome is used to tap the sinus floor into proper position. The dental implant is typically placed during the osteotome sinus lift surgery, and bone integration takes approximately 4-6 months.