How many dental implants do I need to get rid of my denture?

This can be a tricky question.  First, I am going to assume that you want a fixed appliance or at least an appliance that gives you the same chewing power as a fixed appliance.  There are many people that do fine with removable dentures (plates), but then there are others, who really suffer with their dentures.  The empirical fact, however is this:  With a very well fitting pair of dentures (and that is very rare !!) a patient can achieve at most about 15% of their original biting power.  As you can imagine, this can severely limit your nutritional intake as well as your food enjoyment.  Dentures typically cover the whole palate.  Well, it just so happens that a great deal of taste buds are located in the palate, which are suddenly excluded from the tasting experience.

Now, in order to restore such a case to full functionality, we need several implants to gain enough bone anchorage in order to get the patient back to about 90% of their original biting force.  At a minimum 8 implants are recommended in the upper jaw and at a minimum 6 implants are recommended in the lower jaw (the bone is generally denser in the lower jaw !).

Additionally, the upper jaw may still need to be somewhat removable for the patient, so that he or she can clean the support structures for the appliance or prosthesis better.  This is not as often the case in the lower jaw.  The reason for this is that there is usually a flange on the lip side of the upper jaw prosthesis (see pictures below) and a little extension on the palatal side, to assure a good phonetic seal.  It is impossible to clean underneath this type of appliance if it was fixed.  We therefore often make “Fixed-Removable” appliances, which give you the same biting power as a completely fixed appliance, but can be removed for cleaning purposes.  Below are a series of images, which illustrate a “Fixed-Removable” appliance for the upper jaw.

X-ray of 8 implants in the upper jaw

X-ray of 8 implants in the upper jaw

Here we see an x-ray image of implants placed into the upper jaw.  We chose 8 implants to give the patient enough support to be able to chew “steaks” again.  In this image one can see that the lower teeth need some extensive work too, but the patient wanted to get started with the upper arch first, because he could not tolerate his denture anymore.

8 implants in the upper jaw with abutments connected

8 implants in the upper jaw with abutments connected

This image shows the implants in the patient’s mouth.  actually what is visible are the abutments, which are connected to the implants.  The implants themselves are buried in the bone and underneath the gum tissues and are therefore not visible.  These abutments, however are custom milled abutments which exhibit a 3-degree taper.  This is necessary, because the appliance will attach to these abutments via simple friction fit.
Fixed-Removable Appliance

Fixed-Removable Appliance

In this image we can see the appliance itself.  As you can see, it has only minimal extensions of acrylic and no palatal coverage.  The amount of pink acrylic necessary will largely depend on the amount of bone and gum tissue loss that has happened prior to the implant placements.  Once teeth are extracted, bone and gum tissue will shrink away.  That is an inevitable fact.  The less tissue loss we have, the less pink acrylic we have to use.
Palatal side of the Fixed-Retrievable appliance

Palatal side of the Fixed-Retrievable appliance

This image shows the flip side ( the palatal side) of the “fixed-retrievable appliance.  You can clearly see that it is metal re-enforced, in order to give it good stability and fracture resistance.  Furthermore, you can appreciate the “golden” metal caps.  These are the “female” friction components to the custom abutments shown above.  The patient will be able to positively seat the appliance without any rocking and will also be able to “wiggle” it back out.  The chewing power the patient gains is similar to that of a completely fixed bridge.  Additionally, the bone and gum tissue resorption has been arrested.  Since the dental implants are bone anchored devices, they transmit enough of a “stimulus to the bone, to maintain itself rather than resorb.
Please keep in mind that this represents only one out of many appliance options that could have been used in this scenario.  The one which is depicted here is a result of what worked best for this particular patient along several parameters.


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Sinus Augmentation or Sinus Lift Procedure

The Sinus Augmentation of Sinus Lift Procedures are very common bone grafting procedures within the realm of implant dentistry.  Patients are often not quite clear what these procedures actually are, so I would like to

The maxillary sinus on a CT scan 3-D image

The maxillary sinus on a CT scan 3-D image

shed some light on these grafting procedures.  The maxillary sinus is the largest of all sinuses in the head-and-neck area.  It is located just to the inside of the bone in the upper cheek area.  The maxillary sinus starts out as a small air cavity in children and then expands and gets bigger as we grow older.  Once teeth are missing in the back areas of the upper jaw, the sinus will expand even further down towards the jaw ridge from the inside of the jaw bone.  This can be seen on the images on the right, especially the very bottom image, which shows a cross-sectional CT scan slice through the alveolar process of the upper jaw bone.

Now, as the sinus expands, and encroaches upon the alveolar ridge from the inside, you can appreciate that there is a diminishing distance of bone left between the top of the ridge and the floor of the sinus.  If this distance is too small to place one or several dental implants of proper length, we need to perform a sinus lift or sinus augmentation procedure, in order to re-gain this distance.

What is the difference between a “Sinus Augmentation” and a “Sinus Lift Procedure”?  Well, many will use these two terms

A CT Scan Slice through the sinus and alveolar process

A CT Scan Slice through the sinus and alveolar process

interchangeably, however there is a little difference between these two terms.  A “Sinus Augmentation” is a slightly more aggressive procedure, where a window is cut into the bony cheek side wall of the sinus and the sinus membrane is then gently lifted off the sinus floor, until a bone graft is finally placed underneath the lifted membrane.

A Sinus Lift procedure, on the other hand is usually performed right through the hole which is drilled for the implant(s).  No window is cut on the cheek side of the bone.  The Augmentation is usually done, for bigger lifts and the Lift procedure is usually done for smaller lifts.

So when the sinus membrane is finally lifted in either procedure, a bone graft is placed underneath the membrane, which keeps the membrane “tented” up.  For more detailed information on bone grafts see my bone graft post or link to Robert Gougaloff ‘s website.  This bone graft will then “mature” over the next six to 24 months (depending on the type of graft used).  What this

A CT Scan Cross sectional slice from the above image

A CT Scan Cross sectional slice from the above image

has accomplished however, is that the floor of the sinus was effectively “raised” and has thus given us enough room to place one or more dental implants of proper length.

Sinus Augmentations and dental implants can be done in one stage or in two stages, depending on how much residual alveolar bone was left to stabilize the implant.  If it is done in two stages, then the dental implant is usually placed 6 to 12 months following the sinus augmentation, depending on the graft material used.

Sinus Lift Procedures and the placement of dental implants are usually done at the same time, which obviously shortens the treatment time dramatically.  However this can usually be only done if the amount of lift needed is not too excessive.

A video of a Sinus Augmentation procedure can be seen on the following video link: Robert Gougaloff ‘s Sinus Augmentation Video.

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Can a crown be fitted immediately after the placement of a dental implant?

One of the most asked question that I get is whether an implant can be placed and fitted with a crown immediately (or at least a temporary crown). This is especially important to patients, which have lost a tooth in the esthetic zone or the visible smile line.

A very legit question, although most of you probably get a very vague answer on this question. Well, truth be told, there is no simple “yes or no” answer to this. The first question that needs to be answered is whether this is to be done immediately after an extraction (i.e. extract the original broken tooth, place a dental implant and then connect a crown to the implant right away), or at a delayed stage, when the extraction site is already healed up.

In the delayed scenario, the chances are usually much better for that, because we can usually achieve good initial stabilization of the implant due to the better quantity and quality of bone (this usually pertains to teeth in the esthetic or visible smile zone anyways).

In the immediate scenario, the chances are often reduced, due to discrepancies between the geometry of the implant and the remaining tooth socket, the need for grafting and poor implant stability. Unfortunately this is the scenario, where we need to take advantage of this treatment modality the most, because it would facilitate the bone and gum tissue maintenance.

So, in summary, if the implant is stable enough at the time of placement, whether it is right after the extraction of the original tooth or not, and the patient does not have excessive clenching and grinding habits, an immediate crown or temporary crown can usually be placed. To see a series of images of an immediate temporary placed on a dental implant which was placed at the same time, follow the following link: Placement of a dental implant and immediate temporary crown.
or for the PDF version in form of a slide presentation, go to the PDF file: Placement of a dental implant and immediate temporary crown. (This is a 40Mb download, however).

Lastly, you can also connect to my website Robert Gougaloff and go to the “Slide and Photo Center” page to get the PowerPoint presentations.

Immediate Temporary Crown for a Dental Implant

One of the most frequently cited requests by patients is that some type of crown can be put on a dental implant right after its placement.  This is especially the case with front teeth, or the esthetic zone, as we call it.  I can fully relate to such requests, because who really wants to leave a dental office with a tooth missing.  Want it or not, a nice set of teeth is a tremendous confidence builder for many people.  The human gaze is usually drawn to the teeth, right after eye contact is made.  A missing tooth will usually be the focus of attention for quite some time.  Our brain is occupied with this visual input, because it is for most of us here in the United States at least, it is a condition it considers out of the norm.  As you can imagine, this can lead to an embarrasing situation both for the “gazer” and the one being “gazed upon”.

Now, most of the time we are in luck and as dental professionals we can accomodate the patient in this quest.  Much of this decision will depend on two parameters:  How stable is the implant at the time of placement and, if the dental implant and the temporary crown is to be placed right after an extraction, how many roots did the original tooth have.

The stability at the time of placement is very important.  If the implant is torqued into the bone and we can not achieve a certain torque value during the placement, then the implant would be in too much jeopardy, if a temporary crown was immediately connected to the implant.  In this case, other temporization options need to be explored.  A lot of that has to do with the bone density of the patient.

In a scenario where a tooth is extracted and a dental implant is immediately placed, the root anatomy of the previous tooth is very important.

Molar vs Implant

Molar vs Implant

As you can appreciate in the image on the right, the geometry of a dental implant is quite different than that of a molar tooth.  If we were to place the implant in its proper position for this molar, we would ideally place it right into the middle of the tooth.  Just imagine overlaying this implant right down the center of this tooth.  The implant would end up partially in a root socket.  Well, this does not offer a whole lot of stability to the implant in the first place, and it certainly would not survive the load of a temporary. Premolar vs Implant

Premolar vs Imlant
Premolar vs Imlant

Now, in contrast, look at the second image to the right.  Here we see the socket of an extracted premolar, which is a single-rooted tooth (Well, ok …  this premolar has probably been extracted a long, long time ago…).  We can appreciate that the implant placement is a lot easier, since it would fit right into the socket.  If we were to select a larger-diameter implant, which has some taper to it, it would pretty much fill up the socket and probably also have enough torque to accommodate a temporary crown.

Now my sentiment is that immediate temporary crowns should be placed on dental implants whenever possible.  Not only do they look good (well, hopefully), but they also serve the important function of maintaining the gum architecture around the tooth/implant better.  That is important!  In terms of esthetics, I consider the tooth the “picture”, and the gums around it the “frame” – none of it works without the other very well.

I think the reason this is not being done so often is because Implant Dentistry is still a remarkably divided discipline of dentistry.  Because of its lucrativity to the practitioner, there is so much cross training amongst dental specialists, that you almost always have more than one doctor working on your implant case at any given time.  This, of course, makes it very difficult to coordinate the surgical placement of the implant by the surgeon with the manufacture of the temporary crown by the restorative dentist (hmmm, maybe this will be worth another blog in the near future).

Anyhow, the message is that it can be done and should be done whenever possible.  Just to show  you how easyly this can be accomplished, check out this series of slides showing the placement of a dental implant with a temporary crown made by a CAD/CAM device.  This is actually a PDF file of over 40 MB, so it might take some time to download.  It is also available to the right in the files link section under “Immediate CAD/CAM Temporary after Implant Placement”.

As always, feedback and questions are always welcome.