ASK THE DENTIST
THURSDAY, JANUARY 21, 2010
Dear Dr. Mady: I lost both upper right molars a couple years ago and now wish to have them replaced. My dentist sent me to an oral surgeon for a consultation and he said there is not enough bone between my gum and my sinus to place the implants. He said the only way to do it is for me to have a surgery called a sinus lift and later put the implants in. What exactly is this, is this a wise choice and does it usually work? Sara from Ruthven
Dear Sara, What you are saying makes complete sense to me and I will try and explain it so it does the same for you. A sinus lift or sinus augmentation is a very common procedure performed by oral and maxillofacial surgeons and other specialists to make the bone of your upper jaw thicker in the molar and premolar (bicuspid) areas so dental implants have something to bite into. If there is not enough osseous structure there prior to implant placement, the chances of failure increase significantly even if osseointegration (the bone healing into the threads of the titanium implant for strength and success) occurs.
Before explaining the procedure, I would like you to understand why this loss of bone takes place. Because of the anatomy of the skull, the upper jaw or maxilla sometimes has less bone in the posterior areas than the lower jaw or mandible. Bone may have been lost because of trauma, periodontal disease, because there was not a lot to begin with, from excessive shrinking in some individuals after tooth extraction or possibly from a low sinus membrane when the skull was formed. Bone even may shrink over time if the teeth had been extracted and replacement not considered for a lengthy duration. Whatever the case may be, enough bone needs to be in place if the treatment option of implant placement is chosen Sinus size is different in different people and as we age, sinuses can enlarge.
The procedure itself merely involves adding bone between your jaw and the maxillary sinuses on both or one side of your nose. X-rays and often CT scans of your head and sinuses are pre-operatively taken for analysis. The membrane of the sinus is moved upward or lifted during the process to make room for the new bone. The bone that is placed or grafted there may come from cadavers, your own body or from synthetic materials that are presently available. If your own bone is chosen, it will be taken from other parts of your body by the oral surgeon themselves or by an assisting orthopedic surgeon. This bone can come from your mouth but most often is borrowed from your hip and sometimes from the tibia beneath the knee. This is a less vascular area and requires more healing time so the hip is usually chosen. If the hip bone is used, the patient often experiences minor pain and occasionally walks with a limp temporarily.
The procedure is done through your gums above your teeth and there are no visible scars from the outside post-operatively. The healing time before implants can be placed is usually about 4 to 9 months later. The teeth usually can be placed on the implants (restorative phase) about 3-6 months after that. If the graft does not take and the implants can not be placed, the sinus lift can be repeated. Failure rates are low for this procedure. Your surgeon will explain everything during the consent process and you will be able to make an informed decision before proceeding.
This procedure has become extremely more popular over the last 10 to 20 years. The reason for this is because more and more individuals are replacing their missing teeth with dental implants than ever as opposed to removable partial dentures, fixed bridges or no treatment at all.
Any questions for Dr. Mady can be e-mailed to firstname.lastname@example.org and also visit his blog at www.dentalden.com (dental education network)
This column is reprinted with the permission of the author and The Windsor Star. "Ask the Dentist" is written by Windsor dentist (and ECDS member), Dr. David Mady Jr.. The column appears the first Thursday of each month in the Windsor Star. Readers with questions can write to "Ask The Dentist", c/o The Windsor Star, 167 Ferry St., Windsor Ontario, N9A 4M5