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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Can I get a dental implant if I take Coumadin?

Coumadin is an anticoagulant (blood thinner), which reduces the formation of blood clots. It does so by blocking the synthesis of certain clotting factors. A reduction in clotting factors will also reduce the chance of any blood clot formation.

Coumadin is predominantly used to prevent heart attacks, strokes and blood clots in veins and arteries as well as around prosthetic devices, such as artificial heart valves. The down side of Coumadin are the prolonged bleeding times. This is of great concern to anyone who needs to undergo minor surgery.
Many patients who take Coumadin get their INR (International Normalized Ratio) and PT (Prothrombin Time) tested on a regular basis. The Prothrombin time (PT) evaluates the ability of blood to clot properly, whereas the International Normalized Ratio (INR) is used to monitor the effectiveness of blood thinning drugs such as Coumadin (or also Jantoven, Marevan and Waran, which are all brand names for the generic Warfarin).

Most dental surgeons will look for the INR assessed a day prior to surgery, to determine whether it is safe to perform any minor oral surgical procedure, however some also consider the PT time along with the INR. Your cardiologist is always the final decision maker, however. Sometimes they will take you off the Coumadin and switch you over to Heparin a few days prior and after the surgery, sometimes they may just take you off for a couple of days. This will really depend on how high your risk of clot formation is and only your cardiologist can make this decision.

So to answer the original title question: As long as you are carefully monitored and prepared by your cardiologist just prior and after the dental implant surgery, you can get dental implants. There are no published studies showing an decrease in success rates of dental implants in patients taking any of the Warfarins.

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A 100 Watt Laser – And My Doctor Says It Won’t Hurt?!?!

It is an unfortunate business practice, but the sale of medical lasers is largely being promoted by their hardware profile: “X” number of watts, “Y” number of pulses at “Z” nanometers etc.  What is unfortunate about this is that it does not really paint a good picture on what the clinical qualities of a laser really are, because this type of advertising does not really address what kind of “tissue interaction” it produces.  This however is ultimately the most important quality of any laser.  I’ll explain…

First and foremost, the power of the laser (usually displayed in Watts) is the true output power in terms of light energy emitted.  This is in direct contrast to a light bulb for instance.  A 60-Watt light bulb will draw 60 Watts of power out of the socket, but only deliver a fraction thereof as light energy, because most of the power drawn gets converted to heat energy.  In a laser the power rating is NOT what it draws out of the electric socket, but rather the light energy it produces.

Another concept that needs to be addressed is that this power claim describing a laser, can often be misleading.  More often than not, a “high-powered” healthcare laser in the 20 – 100 Watt range achieves this kind or output power mostly in a “pulsed” mode.  This means that the laser will be “on” and “off” several hundred or even several thousand times a second and every time it is “on” it emits 100 Watts.  Since this is a pulse train of laser light, it is important to note that the AVERAGE power may only be in the milliwatt range, so there is effectively only less than 1 Watt being absorbed by the tissues.

The last and most important concept which needs to be addressed is that of the power density at the output tip (aka “fluence”).  A 50-Watt laser with an output diameter of 1 cm will have an entirely different effect on tissues than a 6-Watt laser with an output diameter of only a few hundred microns.  The former will have a biostimulatory effect, whereas the latter will be able to cut tissue.

So, as we can see, the advertising profiles of lasers do not really always reflect the clinical relevance.  It is my opinion that this needs to change eventually, so that the tissue interaction is placed into the foreground and not the hardware profile.


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