Over the last century and a half millions of people have had a tooth cavity filled with “silver” amalgam. Perhaps you’re one of them. The use of this effective and durable filling has declined in recent years, but only because of the development of more attractive tooth-colored materials.
At the same time there’s another issue that’s been brewing in recent years about this otherwise dependable metal alloy: the inclusion of mercury in amalgam, about half of its starting mixture. Various studies have shown mercury exposure can have a cumulative toxic effect on humans. As a result, you may already be heeding warnings to limit certain seafood in your diet.
So, should you be equally concerned about amalgam fillings — even going so far as to have any existing ones removed?
Before taking such a drastic step, let’s look at the facts. To begin with, not all forms of mercury are equally toxic. The form causing the most concern is called methylmercury, a compound formed when mercury released in the environment combines with organic molecules. This is the form certain large fish like salmon and tuna ingest, which we then ingest when we eat them. Methylmercury can accumulate in the body’s tissues where at high levels it can damage various organ systems.
Dental amalgam, on the other hand, uses elemental mercury. Dentists take it in liquid form and mix it with a powder of other metals like silver, tin and copper to create a pliable paste. After it’s placed in a prepared cavity, the amalgam hardens into a compound in which the mercury interlaces with the other metals and becomes “trapped.”
Although over time the filling may emit trace amounts of mercury vapor, it’s well below harmful levels. You’re more likely to encounter “un-trapped” mercury in your diet than from a dental filling. And scores of studies over amalgam’s 150-year history have produced no demonstrable ill effects due to mercury.
Although it now competes with more attractive materials, amalgam still fills (no pun intended) a necessary role. Dentists frequently use amalgam in less visible back teeth, which encounter higher chewing pressures than front teeth. So, if you already have an amalgam filling or we recommend one to you, relax — you’re really in no danger of mercury poisoning.
On the big screen, Australian-born actress Margot Robbie may be best known for playing devil-may-care anti-heroes—like Suicide Squad member Harley Quinn and notorious figure skater Tonya Harding. But recently, a discussion of her role in Peter Rabbit proved that in real life, she’s making healthier choices. When asked whether it was hard to voice a character with a speech impediment, she revealed that she wears retainers in her mouth at night, which gives her a noticeable lisp.
“I actually have two retainers,” she explained, “one for my bottom teeth which is for grinding my teeth, and one for my top teeth which is just so my teeth don't move.”
Clearly Robbie is serious about protecting her dazzling smile. And she has good reasons for wearing both of those retainers. So first, let’s talk about retainers for teeth grinding.
Also called bruxism, teeth grinding affects around 10 percent of adults at one time or another, and is often associated with stress. If you wake up with headaches, sore teeth or irritated gums, or your sleeping partner complains of grinding noises at night, you may be suffering from nighttime teeth grinding without even being aware of it.
A type of retainer called an occlusal guard is frequently recommended to alleviate the symptoms of bruxism. Typically made of plastic, this appliance fits comfortably over your teeth and prevents them from being damaged when they rub against each other. In combination with stress reduction techniques and other conservative treatments, it’s often the best way to manage teeth grinding.
Orthodontic retainers are also well-established treatment devices. While appliances like braces or aligners cause teeth to move into better positions, retainers are designed to keep teeth from moving—helping them to stay in those positions. After active orthodontic treatment, a period of retention is needed to allow the bite to stabilize. Otherwise, the teeth can drift right back to their old locations, undoing the time and effort of orthodontic treatment.
So Robbie has the right idea there too. However, for those who don’t relish the idea of wearing a plastic appliance, it’s often possible to bond a wire retainer to the back surfaces of the teeth, where it’s invisible. No matter which kind you choose, wearing a retainer can help keep your smile looking great for many years to come.
If you have questions about teeth grinding or orthodontic retainers, please contact our office or schedule a consultation. You can read more in the Dear Doctor magazine articles “Teeth Grinding” and “The Importance of Orthodontic Retainers.”
Crowns are a mainstay of cosmetic dentistry used to improve your smile’s appearance in a variety of situations. Not all crowns are alike, though — and the differences could affect your cost.
Crowns or caps are needed to cover remaining tooth structure which was previously damaged. Tooth decay and trauma are the major reasons for damage or loss of tooth structure that make crowns necessary. After preparing the remaining healthy tooth to fit into the new crown, we then make an impression mold of the tooth for a dental technician to use to create the new crown. It’s at this point where the road to your new smile can take different paths, both in construction and how much artistry goes in to your crown’s formation.
Porcelain crown construction falls into two general categories. The first category involves life-like porcelain fused to an inner core of metal. Because many older types of porcelain tend to be brittle and subject to breaking under pressure, metals are used to strengthen the crown. A fused crown can thus provide both durability and a life-like appearance.
In recent years, though, new dental materials have made the second category — all porcelain crowns — a viable option. Either lithium disilicate or zirconium oxide account for nearly two-thirds of crowns made today. Although research on their durability is relatively new, initial results have been encouraging, showing advanced all-ceramic crowns can tolerate forces comparable to porcelain fused to metal (PFM) crowns used in bridges.
On the downside, these newer materials may be more expensive than PFM crowns. Costs for manufacturing may also increase depending on how life-like the matching of color with other teeth you desire your crown to be. For example, individual teeth aren’t a uniform color — there are gradations of color that can vary from the tip of the tooth to the root. To capture these gradations in an individual crown requires a high level of artistry and time by the dental technician, which increases the final cost.
If you’re in need of a crown, it’s best to first make an appointment for a consultation to review your options, and to consider both your expectations and financial ability. Together we can determine what it will take to create a new look for your teeth that fits your expectations and your budget.
As a new permanent tooth develops, the roots undergo a process of breakdown and growth. As older cells dissolve (a process called resorption), they’re replaced by newer cells laid down (deposition) as the jaw develops. Once the jaw development ends in early adulthood, root resorption normally stops. It’s a concern, then, if it continues.
Abnormal root resorption most often begins outside of the tooth and works its way in, beginning usually around the neck-like (or cervical) region of the tooth. Also known as external cervical resorption (ECR), the condition usually shows first as pink spots where the enamel is being undermined. As these spots continue to erode, they develop into cavity-like areas.
While its causes haven’t been fully confirmed, ECR has been linked to excessive pressure on teeth during orthodontic treatment, periodontal ligament trauma, teeth-grinding or other excessive force habits, and bleaching techniques performed inside a tooth. Fortunately, ECR is a rare occurrence, and most people who’ve had these problems won’t experience it.
When it does occur, though, it must be treated as quickly as possible because the damage can progress swiftly. Treatment depends on the size and location of the resorption: a small site can often be treated by surgically accessing the tooth through the gum tissue and removing the offending tissue cells. This is often followed with tooth-colored dental material that’s bonded to the tooth to replace lost structure.
A root canal treatment may be necessary if the damage has extended to the pulp, the tooth’s interior. However, there’s a point where the resorption becomes too extensive to save the tooth. In these cases, it may be necessary to remove the tooth and replace it with a dental implant or similar tooth restoration.
In its early stages, ECR may be difficult to detect, and even in cases where it’s been diagnosed more advanced diagnostics like a CBCT scanner may be needed to gauge the extent of damage. In any case, it’s important that you have your teeth examined on a regular basis, at least twice a year. In the rare chance you’ve developed ECR, the quicker it’s found and treatment begun, the better your chances of preserving the tooth.
There’s a lot to like about replacing a missing tooth with a dental implant. This state-of-the-art restoration is by far the most durable and life-like option available. And unlike other replacement options implants stimulate bone growth, a major concern after tooth loss.
For that reason we encourage getting an implant as soon as possible — for adults, that is. We don’t recommend implants for younger patients because even a teenager’s jaws haven’t yet reached full maturity. Because it attaches to the jaw differently, an implant can’t move with the growing jaw as real teeth do. It would eventually look as if it were sinking into the jaw below the gum line or being left behind as the rest of the jaw grows.
It’s best, then, to postpone placing an implant until the jaw fully matures, usually in a patient’s early twenties. In the meantime, there are some things we can do to prepare for a future implant while also restoring the tooth with a temporary replacement.
As previously mentioned, our biggest concern is bone health. Like other living tissue, bone has a growth cycle of older cells dissolving and newer ones forming in their place. The teeth transmit the pressure produced when we chew to the bone to stimulate this growth. With the absence of a tooth, the adjacent bone no longer receives this stimulation — the growth cycle slows and may eventually lead to bone loss.
We can help this situation by placing a bone graft in the missing tooth socket at the time of extraction. The graft serves as a scaffold that’s eventually taken over and replaced by new bone growth. We can also try to control how fast the graft is replaced by using grafting material that’s slowly removed and lasts longer — often a preferable situation if an implant is years away.
As for appearance, we can create a custom partial denture or even a type of bridge that bonds a prosthetic tooth to neighboring teeth without significantly altering them. If the patient undergoes orthodontic treatment it’s also possible to add prosthetic teeth to an orthodontic appliance.
Eventually, we’ll be able to provide the permanent solution of a dental implant. With careful planning and measures to preserve bone health, there’s a good chance the outcome will be worth the wait.
If you would like more information on treatments for lost teeth in children and teenagers, please contact us or schedule an appointment for a consultation. You can also learn more about this topic by reading the Dear Doctor magazine article “Dental Implants for Teenagers.”
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