Most dentures today are made of the same basic material, PMMA. In recent years, other materials have begun to be used, such as nylon and other types of acrylics. 3D printed dentures are also in development which can be composed of a variety of different plastics, but PMMA has the longest track record of success, and has been in use for decades. PMMA has a low incidence of allergy or sensitivity in patients and is durable, repairable, and can be relined. Some of the newer materials come up short in some areas.
Not all PMMA is equal, though!
PMMA is formed by combining powdered polymer with a liquid that causes the polymer molecules to bond together and form long chains. The polymer molecules will also crosslink, resulting in a web of bonded molecules. The higher quality, more durable types of PMMA have longer chains and more crosslinking. There are many manufactures of PMMA, and the strength of the finished materials is different for different manufacturers.
In addition, PMMA can be processed in different ways. Cold poured PMMA acrylic uses a higher amount of liquid, with less polymer molecules, to allow the acrylic to flow into a mold without pressure. This type of acrylic can be processed more quickly than acrylics that are pressure molded, making it cheaper for the denture lab. However, this acrylic is less dense and more prone to warping during processing, which can result in easier breakage and a poorer fit.
Some dental labs use cheap or cold pour acrylic, but charge as much as others that use higher quality pressure cured acrylic. If you are going to invest in a denture, it's worth it to find out what type of acrylic the lab is going to make it out of. It doesn't hurt to ask them!
There is a lot of debate going on right now about the safety of amalgam fillings, also called mercury, or silver fillings. The material used in these fillings is a combination of metals, including mercury and silver. When mixed together, they create a pliable material which quickly hardens into solid metal. Liquid mercury is present before the components are mixed, but the mercury combines with the other metals to form a solid alloy.
The concern over amalgam relates to how much of this mercury later escapes into the body as the filling ages. Amalgam has been in use for about 150 years, and there is actually no clinically documented cases of mercury toxicity from amalgam fillings during that time. However, in recent years, evidence has shown that a small amount of mercury is released by the amalgam as it ages and wears down. The amount of mercury released is considered by many experts to be less than the amount that most people are exposed to during daily life, from other sources like seafood. However, the amount of mercury from fillings does add to the total amount someone is exposed to, so some experts believe that if a person is exposed to a large amount of mercury from other sources, it may be wise to avoid mercury fillings. Such a situation might arise if a person eats a significant amount of seafood regularly, or works in a profession where they are exposed to mercury. For the average person, though, neither the American Dental Association, nor the FDA, advise against having amalgam fillings done, or having old amalgam fillings removed, unless they are defective.
There is a great article on the Colgate website that discusses this issue here.
There is a link in this article to the FDA’s official amalgam information page as well.
Personally, I have several amalgam fillings that have served me well for over twenty years, and don’t have any plans on getting them removed. However, I believe that treatment choice is ultimately up to the patient. If someone believes that any mercury released by their amalgam fillings is too much, no matter the amount, that is their right, and I will gladly remove and replace them.
This question usually comes up regarding dental insurance coverage, and insurances are pretty picky about which word you use. Interim dentures (and partial dentures) are temporary dentures. They are placed at the time of the extractions, and then are replaced with a new set once healing is over. This allows us to retain the pre-extraction bite, but gives the patient more control over the appearance of their final set. We can also make major adjustments to the interim dentures to get them fitting just right, without worrying about messing up the final set.
Immediate dentures are placed at the time of the extractions, but are intended to be used long-term. After healing is over, these undergo a hard reline, which means the inside surface of the denture gets a new layer of acrylic that fits the shape of the healed gums it rests on. The teeth, however, stay the same. While we can usually make a great looking immediate denture, it does not give us the ability to make appearance modifications before it is placed, as we can with an interim denture and its final replacement.
Here’s an example of one of our immediate denture cases:
Your denture probably needs a reline. Over time, the bone that used to contain your teeth tends to shrink, but your implants don’t shrink down with it. When your denture was brand new, it rested directly on your gums, and distributed the pressure of your bite across a wide area, but as the bone shrinks, the denture loses that support and the pressure of your bite is concentrated on top of the implants. It’s pretty similar to snapping a twig over your knee. Having a denture made of high impact acrylic definitely helps, and dentures can actually be made with metal reinforcement to increase their strength, but if yours is already cracked, having a reline done may keep it from cracking again. A reline adds more acrylic to the inside surface of the denture, allowing it to rest on your gums once again, and taking pressure off of the implants.
Even without implants, dentures that are in need of a reline tend to crack, especially upper dentures. That’s because the bone where the teeth used to be shrinks, but the palate doesn’t, with leaves the denture high centered down the middle, resulting in a crack that usually starts at the maxillary central incisors, and runs toward the back of the denture.
All dentures, whether there are implants present or not, should be relined every two to three years to prevent cracking, and more importantly, to prevent damage to the alveolar bone. Dentures that have not been relined properly can cause bone loss to accelerate!
My short answer to that question is YES!
Here’s the long answer:
I can’t believe that there is actually any debate about this, but in an article written by Jeff Dunn, published by the Associated Press, on August 2, 2016, Mr. Dunn asserts that flossing might not actually be effective, and seems to insinuate that dentists have been pushing people to floss simply to help dental floss manufacturers make a profit.
Mr. Dunn’s major point is that he believe the existing studies which show floss to be effective are flawed. I actually think this is entirely possible, but just because the studies were not done correctly, does not mean flossing is not effective. Flossing has been recommended by the American Dental Association for about a hundred years. Dental floss probably came into use about the same time that humans invented string. When the ADA first recommended its use, studies were not conducted the same way they are today, and it has always been an accepted practice based on observed results of patients by practicing dentists.
I believe Mr. Dunn has stumbled onto an area of weak study based evidence, which exists simply because until he made a stink about it, nobody cared about having any better study. Dentists have always recommended flossing because they can see the results with their own eyes. After this article, we may see more thorough studies performed, which I believe will support the effectiveness of flossing.
I don’t really feel the need for additional studies to recommend flossing, though. I base my opinion on years of face to face observation of patients and their teeth. Patients I have personally examined, who admit that they do not floss, or only floss occasionally, consistently have more dental problems than those who regularly floss. For me, it’s that simple. As my hygienist put it: “The evidence is on the floss!” One only has to look at the chunks of gunk on the floss after using it to see that it’s been beneficial.
So there’s my two cents. You can accept the opinion of someone who has personally examined and spoken to hundreds of dental patients, backed up by thousands of other dentists who have observed the same thing, or you can take the word of a reporter, who has written his opinion based on second hand information. I question Mr. Dunn’s motivation for writing the article. Does he believe he has uncovered some kind of injustice? A scam perpetrated by the dental industry against their own patients? Or possibly: Mr. Dunn just hates flossing like most people and wrote this to make himself feel better about not doing it?
We have a saying in the dental industry: “Only floss the ones you want to keep.” I believe this to be literally true! I believe Mr. Dunn’s article is harmful, and urge anyone reading this to continue flossing regularly. If you decide to follow Mr. Dunn’s advice, though, I will be standing by to repair the damage.
It depends on which digital process is used. The term digital dentures is becoming well known in the denture industry lately, but most people don't know exactly what that means. In as simple an explanation as possible, digital dentures are fabricated either by 3D printing, or by computerized milling. 3D printing uses a liquid resin that is cured layer-by-layer to fabricate the teeth and denture base. Milled dentures are carved from a solid block of pre-cured material. The fit of either type is largely dependent on the skill of the technician that designs the denture and operates the equipment, just as with traditional dentures. The real difference between traditional and digital dentures is with durability. Milled dentures can be very durable if fabricated correctly, and may equal or even surpass traditional techniques. 3D printed dentures, however, still come up short in strength and durability compared to traditional PMMA dentures. If you are considering digital dentures, it's important to ask what type you are getting, how long the material is expected to last, and how long it is warrantied for. Here is a link to a study that discusses these issues: Strength and Surface Properties of a 3D-Printed Denture Base Polymer - PubMed (nih.gov)
You should think of your implants like real teeth. They need to be kept clean. Implants don't get cavities, but they can suffer gum problems similar to periodontal disease. Maintaining healthy gums is important. Remember to take your dentures out at night. Twice a day, brush your implants with an extra soft toothbrush, focusing on keeping the gumline around them clean. It's ok to use toothpaste, or use mouthrinse to dip your brush in. Crest ProHealth is a good rinse to use. You should also come in to get the implants cleaned professionally. Implants tend to develop tartar buildup, which must be removed by a hygienist. Depending on how much tartar you naturally develop, you should come in once or twice a year for a quick cleaning.
The colored caps inside your dentures will wear out over time. These will need to be replaced every six months to a year or so. Also, it's important to be sure that the caps are fully snapped in place while wearing the dentures. If not, the center of the nylon cap will be crushed by the top of the implant, resulting in premature cap failure. If the denture isn't snapping in properly, contact your dentist. Also, the depression in the top of the implant can become filled with tartar or debris. If the denture isn't snapping in, check the top of the implants. If you have trouble cleaning the debris out, contact your dentist.
Dry mouth, or xerostomia, can cause a loss of suction for dentures. Xerostomia is a very common problem for older patients, and is exacerbated by many common prescription medications. There are prescriptions available that can stimulate saliva production, but they are rarely used due to potential side effects. Oral treatments are also available, such as Biotene rinse, spray, or lozenges. Many people use hard candy as a way to stimulate saliva production. Try to stick with the sugar-free variety! No matter what method is preferred, though, dry mouth is a challenge for denture wearers, and may require the use of denture adhesive to secure even well-fitting dentures.
I have placed hundreds of first dentures and partials, both on the day of extractions and for people whose gums have already healed. In my experience, if you are having multiple teeth extracted, it’s better to place a set of dentures at the extraction appointment, rather than waiting for healing, for several reasons:
1. The first regards swelling. After the teeth are extracted the gum tissue will temporarily swell, but what many people don’t know is that the bone will also swell. Alveolar bone, the stuff that the teeth are held in, is spongy bone. The interior of the bone resembles a sponge, with a thin hard shell on the outside. After extractions, the spongy part can swell, pushing the shell outward. This can cause a ridge or points under the gums that will not shrink back down when the pink gums lose their swelling. Even after a prolonged period of healing, these points remain and can make it difficult for you to wear your first set of dentures without sore spots. A denture placed at the extraction appointment acts like a pressure bandage, keeping the shell of bone from swelling outward and resulting in faster healing and smoother gums with fewer sore bumps and ridges.
2. The second regards muscle memory. Before your teeth are extracted, your muscles and nervous system know exactly how to close your lower jaw so that your teeth fit together correctly, without having to shift around. When a person has been missing all their teeth for a prolonged period of time, they lose that muscle memory. It may be difficult to get a comfortable bite with your dentures if they were created after your muscles have forgotten how they are supposed to line up. If the dentures were made to be placed at the time of extractions, however, they are created using your pre-extraction bite, and are more likely to line up correctly.
3. The third regards your tongue, and the back of your throat. I’ve found that patients have less gagging from their new dentures, and feel like their tongue is less crowded, if their dentures are placed at the time of their extractions. At that time, your tongue is used to sharing space with your teeth. If all the teeth are gone for a period of time with no dentures, the tongue pushes out to fill the extra space, and then doesn’t like to be squeezed back when dentures are finally placed.
4. Forth, it’s just nice to not have to go six months or more without teeth! If you are having multiple extractions, most experts will tell you that six months is the minimum you want to allow for healing. My team here at AdaCare is very good at making great looking dentures from day one, and we work with you through the entire healing period.
Lower dentures are generally more loose than upper dentures, but if you’ve noticed your lower denture stays put until you start eating, it may be due one of these issues:
Both of these issues are often correctable, and the fit of your lower denture significantly improved, even without dental implants!