In the first part of this blog, I talked about why not to use denture adhesives. Once all the reline procedures have been tried, there are occasional instances where there is still not enough bone to provide enough surface area for adequate retention and stability. In those cases, a patient will usually have to rely on denture adhesives. Also on cases where a patient would be too self-conscious about a denture slipping while out in public, denture adhesives can be helpful. Denture adhesives come in powder, paste, or adhesive pads. Any of the forms work reasonably well, so which variety or brand is totally up to personal preference. There has been a lot of talk lately in the media about zinc in denture adhesives. Too much zinc in the body can cause nerve damage. It turns out that patients who were experiencing symptoms of zinc toxicity were overusing the product. Only the smallest amount of denture adhesive should be used and that should minimize any toxic effects. Lately, many companies have reformulated their products to be zinc-free, so that would alleviate any concerns.
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Denture adhesives are used to help retain dentures in the mouth. Before denture adhesives are used, a dentist should be consulted. Ill fitting dentures can cause areas of chronic irritation which can lead to mouth sores and ulcers and eventually could be a source of malignant transformation. Mouth cancer is not something to be taken lightly, so a dental examination is always best to have before considering denture adhesives. Most ill-fitting dentures can be relined with new plastic to have them conform to the gums better. When teeth are removed, the body realizes that there is no need for the bone to hold the teeth in, so it slowly allows the bone to dissolve. Since the denture plastic doesn’t change, gaps begin to form which causes a loss of suction. A reline will fill in the gaps, restoring the suction. There are other times, especially on the lower, where there is not enough bone for adequate retention and stability. In this case, it is best to train the muscles to keep the denture in place while chewing and talking. This will allow the denture to stay in place during function.
A good fitting denture along with an adequate amount of saliva will usually allow a denture to fit well without the use of denture adhesives. However, over time, the gums will naturally shrink and thus the dentures will begin to loosen. The better thing to do is to go to your dentist for a reline. An impression is made of the new gums and new plastic is processed into place giving the denture a fit that is as good as new. In the interim, denture adhesive can be used, but it should not be relied on as ill-fitting dentures can be a source of chronic irritation that could possibly lead to malignancy. Another reason that denture adhesive may be needed is very flat gum ridges. If there is not enough bone present to resist the lateral forces of chewing, the denture could become continually dislodged.
There are a number of varieties of denture adhesives, mostly pastes, powders, and wafers. All types seem to work reasonably well, although pastes should only be used sparingly because they tend to be very thick in viscosity and could throw off the proper fit of the denture.
Over the years, dentures will become looser and looser. This is not because the denture is changing but because the gums are shrinking. Alveolar bone (the bone that holds the teeth in) is very labile bone. That means that it is constantly changing to meet the current conditions. This is an important property due to the constant changes in the forces while chewing with natural teeth. However, the sole purpose of alveolar bone is to hold the teeth in, so once a tooth is removed, it thinks that its job is done and begins to resorb. When the teeth are first lost, there is usually a fair amount of bone left behind, unless there was severe periodontal (gum) disease present. However, as time goes on, the bone will continue to erode until eventually, there will not be much left. Since the bone shrinks, dentures must be periodically relined.
To reline a denture, impression material is placed into the actual denture to make a mold of the changed gums. A technician will then grind out the old plastic and process new plastic to perfectly match the present situation. This is a much less expensive way to make an old set of dentures fit as good as new, and avoids the great expense of an entirely new set.
Sore Spots in Dentures
Sore spots under dentures can be extremely aggravating. They are caused by an area of extra pressure consistently rubbing against the oral mucosa. It causes a tell-tale ulceration of the tissue. Even the tiniest ulcer can make the whole denture feel extremely uncomfortable to wear. Just like a pair of shoes. An area of the shoe that is ill-fitting to the foot and slips and slides with every footstep, it can rub an area raw in a very short amount of time. When a sore spot occurs under a denture, it is always best to get to your dentist for an adjustment. Don’t try to fight through it as it can only make the problem worse.
In the interim, you can place a salve that contains a local anesthetic onto the sore. I usually recommend Orabase with Benzocaine. A tiny dot of that will numb the area and stick to the tissue for up to a few hours. It is important to wear the denture for 24 hours before your dental appointment. If it is left out for a significant amount of time, then the area could heal and be difficult for the dentist to spot. When the denture has been worn the day before, the dentist will be able to see exactly where the sore spot is. This way he can mark the exact location and grind on the offending area of the denture. By relieving that area, it allows the pressure of chewing to be spread over a large area thus allowing the sore spot to heal.
Caring for Dentures
Dentures require care that is different from natural teeth. For brushing a denture, one must keep in mind that toothpastes that are meant for real teeth contain abrasives to remove stains from the enamel surfaces.
But dentures are made from an acrylic plastic that is much softer than tooth enamel and cannot hold up to a frequent brushing with a harsh substance. It is also best to use a brush that is specifically made for dentures. The nylon bristles in a normal toothbrush can be stiff enough to cut grooves into the plastic. Over the years, I have observed dentures that aren’t even recognizable due to the meticulous scrubbing with abrasives. Another thing that can help are tablets of denture cleanser that you drop into warm water and they will effervesce plaque away from the denture. You still have to go over the denture with a gentle brushing to get the remaining deposits off. When cleaning a denture, it is usually best to do it over a sink full of water or a towel. All it takes is one slip and the denture could fall against a hard sink and crack in two. If there are any stains or deposits that do not come off with a gentle brushing, it is best to bring it to the dentist and have a professional clean them.
Getting Used to New Dentures
Once new dentures have been delivered, there can be a big learning curve on getting them to function properly. For those who have not had dentures before, it can be a huge adjustment. Chewing power is greatly diminished from the natural teeth. Foods that are extremely hard must be avoided so as to not crack the plastic. Food should be cut into smaller pieces and should be distributed to both sides of the mouth so that the denture does not get dislodged during function. One must learn to manipulate the cheek, lip, and tongue muscles in order to keep the suction seal intact and (especially on the lower) to keep it in place while chewing. The dentures are kept in place by a thin layer of saliva which helps maintain a suction to keep an upper denture from falling. But moving ones lips the wrong way can cause the denture to lose suction. Food will taste different because plastic is covering the roof of the mouth which insulates it from temperature and changes the appeal of food. Speech will also have to be re-learned, especially “s” sounds. It is helpful to go into a room alone and repeat “Mississippi” over and over again until an “s” can be easily articulated.
The big day has finally come, after all of the impression and try-in appointments, the actual dentures will be delivered. Upon first inserting the dentures into the mouth, they may feel tight and foreign. Sometimes, there are little spicules of plastic that come from voids from air bubbles in the model. These can easily be removed. The next thing to check is the bite. Even though the bite is verified during the try-in appointment, there are processing errors that creep into the plastic which can cause the bite to be off. Once the bite has been adjusted, then the cosmetics can be checked to make sure that they didn’t change from the try-in. Then a final check is done by moving the lips and tongue to make certain that the denture does not become dislodged. Now it’s time to take them home and try them out for real. It is important to not have unrealistic expectations. For new denture wearers, one must understand that they will not function the same as natural teeth. The chewing power is not near as good and they can become dislodged by certain movements of foods. For those who have worn a previous denture, the new denture will not feel the same as the old one. It’s just like getting a new pair of shoes. Even though the old pair has holes in them and are falling off your feet, the new pair usually feels very different. But when one walks in the new shoes for a few days, they will feel totally natural. This is the same with dentures. Sometimes you have to force yourself to wear the new set because they feel so foreign, but after a few days, they should function naturally.
A denture try-in is an extremely important phase of denture construction. One must start with a perfect reproduction of the gums obtained by taking an extremely accurate impression. The resulting models made from the mold are mounted on an articulator, a machine that is used to reproduce jaw movement. At this point, a lab technician sets the denture teeth into a wax base that will represent the gum portion of the finished denture. Now comes the try-in phase. The first thing that is checked is the bite. The denture teeth must meet the same way natural teeth do, so it is of utmost importance that a proper bite is verified before the dentures are constructed. Next comes the cosmetics. The dentist checks for the proper alignment of the front teeth to make sure that the patient has a great smile. The patient is then given a mirror so that they can approve the shape and color of the teeth. Since the teeth are set in wax, changes can be readily made by merely heating the wax and resetting the teeth. The patient is then instructed to say a few words to make certain that they will be able to properly speak with the dentures in. Lastly, the far extent of the hard palate is measured to make certain that the denture will not protrude too far to the back of the mouth. The denture is now ready to send to the lab for construction of the final product.
Once the dentist has done an oral cancer exam and checked for good health of the oral mucosa, then the patient is ready for an impression (or mold) in order to construct a complete denture. To make this impression, the dentist first prepares a tray to hold the impression material. This tray can be made in a lab from a preliminary impression or a stock tray can be modified to fit the mouth. The borders of the tray must be properly molded so that they do not protrude too high up into the cheek. If it did, then the resulting denture would constantly rub causing a sore spot. There are a number of impression materials available. The one I prefer to use is a vinyl polysiloxane. It has a rubbery consistency when set and is so accurate that I also use it for precision crown and bridge procedures. It also has a pleasant taste which can be a big factor when one has a mass of goo in their mouth. The material is mixed and placed in the mouth and allowed to set. A special plaster is poured into the resulting mold and a perfect reproduction of the patient’s gums can be produced.