Category Archives: Dentistry

Denture Impressions

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Upper Impression for Denture

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.

Denture Impressions – Preliminary Steps

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The construction of a full denture starts with an impression of the gums. The dentist must first check to see if there are any suspicious lesions that could be a malignancy. X-rays should be taken to make certain that there are no tumors inside the bone. The dentist must also make certain that there are no bony undercuts which would prevent the denture from properly seating or flabby gum ridges which would not provide a stable surface for the denture to function. Any of these problems would require surgical intervention plus a healing period before final impressions could be made. The dentist must also check the condition of the gum tissue itself.

Maxillary (upper) gum tissue

If the gums are swollen, red, and inflamed especially due to sleeping in the dentures or from smoking, then steps must be taken to relieve the inflammation. Many times, merely leaving the dentures out while sleeping for a week or two will allow the gums to heal. In more resistant cases, a tissue conditioner can be applied to the current denture. This conditioner is a resilient liner. Its soft nature can give the gums a chance to heal. Once all of the preliminary steps have been taken, the final impression can be made.

Immediate Denture

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A dentist’s goal is to save teeth, however, if there is too much decay or gum disease or the financial situation is not good enough to properly restore the teeth, then the fateful decision must be made to remove the remaining teeth. There are two ways of handling the construction of the first set of dentures. One method is to wait for one full month to allow the gums to heal and shrink. At this point, an impression (or mold) is made of the gums and denture construction begins. The other method is an immediate denture. An immediate denture is constructed before the teeth are removed. The advantage of that is that the denture is inserted on the day of the surgery. This way the patient never has to go around without teeth. Unfortunately, there are compromises. There is no way to do a try-in to check the cosmetic arrangement of the teeth, the function, or phonetics (ability to speak with the dentures). It’s possible that the resulting pre-made denture could be far enough off that it may have to be remade. The other issue is that the gums will shrink after surgery, so the denture will have to be relined after about six months. This way the inner part of the plastic of the denture will match the new healed gums. An immediate denture would at least save one from the embarrassment of being without teeth for any length of time.

Apexification

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When a child receives a blow to the mouth and injures a front tooth, there is always a chance that the blood supply to the dental pulp (or nerve) will be severed, causing the nerve to die. In this case, root canal treatment would be indicated. However, if the child is of a younger elementary school age, the end of the root has probably not matured yet.

Immature vs Mature Root Structure

This is a situation called an open apex. The apex is the tip of a tooth root. In a normal root canal, an inert filling material is packed against the apex to seal the end of the root. With an open apex, there is nothing to pack against so there is no way to get a good seal. Fortunately, there is a procedure called apexification that will stimulate the body to close the apex. After the root canal has been thoroughly cleansed of debris, a calcium hydroxide paste is inserted at the root end. The calcium hydroxide is very alkaline. The body reacts to this high pH by depositing hydroxylapatite crystals (the basic building blocks of teeth) at the site. It takes a few visits spaced out over a year’s time and then the canal can be properly sealed. Using this procedure will allow a front tooth to be retained, saving the child from years of embarrassment and numerous tooth replacements.

Tooth Trauma (Part IV of IV)

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When a front tooth has been chipped, there are a few options on restoring the tooth. If the chip is small enough, the area can be repaired by bonding tooth colored filling material to the enamel. I have many cases where that repair has lasted over ten plus years.

Porcelain Crown

Large defects are better repaired by covering with a porcelain crown. The porcelain is extremely durable and color-stable and can last decades. With children, when a majority of these injuries occur, it is better to do a tooth colored filling, even with large fractures. The main reason is that at least a millimeter and a half of tooth enamel needs to be removed from the tooth in order to get a good cosmetic result and in a child, the nerve in the center of the tooth is extremely large. Taking 1.5 mm of enamel in a patient of that age group can be enough to either expose the nerve or injure it enough that root canal treatment would be needed later on. Also, in a child, the tooth continues to erupt out of the gums, so as the child matures, the edge of the crown can become exposed which can be very unsightly. When a tooth colored filling is done to repair a fracture, it is expected that it will have to be repaired or redone many times during the patient’s lifetime.

Tooth Trauma (Part III of IV)

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If a tooth has been displaced in a traumatic accident, as long as the x-ray doesn’t show any root fractures, then the dentist can usually move the tooth back into its original position. Then, the tooth is usually splinted to the adjacent teeth during the healing period. This is done by attaching a wire to the front teeth with composite. Composite is the tooth colored filling material routinely used to fill cavities.
When one of the teeth has been chipped, the primary focus tends to be on that tooth. However, in a traumatic injury to the mouth, it is not unusual to have multiple teeth having been injured. When a tooth fractures, then, the force of the blow is dissipated. Unfortunately, the intact teeth will transmit all of the energy of the insult directly onto the end of the root. The problem with this is that the end of the root is where the nerves and blood vessels enter the tooth. If the force is great enough, then the nerve and blood vessels can be severed. This will cause the nerve to die and will necessitate root canal treatment to save the tooth. It’s hard for a dentist to tell right away whether a traumatically injured tooth may need root canal treatment. Many times, it takes up to six months before a dead nerve can be detected, and there are times that the damage will show up decades after the initial injury.

Tooth Trauma (Part II of IV)

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If a front tooth has been chipped in a fall, and there is no telltale red dot in the center of the tooth indicating an exposure of the nerve, then immediate treatment is not necessary. It’s likely that the tooth would be very sensitive to cold, so cool liquids are best to be avoided. The tooth could also be painful to chew on. It is usually best to wait until your dental visit to rule out root fractures before attempting to chew on a traumatically chipped tooth. The teeth could also ache so a pain reliever with anti-inflammatory properties would be most helpful. Ibuprofen tends to work the best. Over-the-counter preparations come in 200mg tablets, so an adult could take as many as four tablets, for a total of 800mg per dose to stay comfortable. Once at the dental office, the dentist will x-ray the teeth, check for root fractures, and check for loose or displaced teeth.

X-ray of Root Fractures

If the root is fractured, the tooth may or may not need to be removed. It depends on where the fracture is. The closer to the end of the root, the better the chance that the tooth could be saved. If there are any teeth that are loose, they may need to be splinted in place. This would be just like placing a cast on a broken arm to allow for undisturbed healing.

Tooth Trauma (Part I of IV)

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Whenever a tooth is injured in a fall, there are certain steps that one must take. First and foremost, a head injury must be ruled out. When one has fallen or received a blow to the mouth, it is not uncommon to also incur trauma to the head. Especially when a tooth has been chipped and there is blood in the mouth, the focus of attention can be on the oral cavity. If there are any symptoms such as dizziness or loss of consciousness, a physician should be consulted. Once head injury has been ruled out, then the focus can be placed on the mouth. If a front tooth was chipped, look for a small red dot toward the center of the tooth.

Exposed nerve/ "red dot" after trauma

This should be checked after any blood has been rinsed away. The red dot is the tooth’s nerve. If it is exposed, there is a fairly high likelihood that it would need root canal treatment. A dentist should be consulted as soon as possible in that situation. The next thing to look at is to see if any teeth are loose or displaced. Again, if either of those conditions are present, a call to your dentist would be in order. Otherwise, it would be best to see your dentist at your earliest convenience so that he can x-ray the tooth to make sure that there are no fractures under the gums.

IV Sedation in Dentistry

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It is not unusual to have some apprehension before a dental appointment. Most, if not all, of that normally goes away once the area to be treated has been numbed. However, some people have dental phobias, usually related to past, unpleasant experiences that make even a routine dental visit a stressful occasion. For most of these people, either nitrous oxide and/or oral sedation is adequate to quell the fears, but there are still a few who need deeper sedation. There are a number of wonderful medications that can be delivered intravenously. Since these are given IV, they can be titrated (adjusted) to the perfect level for each individual patient. We use Versed (midazolam) in our office. It is a very safe sedative that can fully relax a patient, but keep their protective reflexes and their ability to respond to commands intact.

Monitor vital signs

We monitor vital signs continuously to assure the highest level of safety. It is important that the patient does not have anything to eat or drink after midnight. They also must have a ride home after the procedure and should not drive or operate machinery for the next 24 hours. The addition of IV sedation to a dentist’s armamentarium can make a dental procedure extremely pleasant for even the most fearful patient.

Nitrous Oxide Sedation

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Administration of Nitrous Oxide

Nitrous oxide (laughing gas) is an extremely helpful adjunct for dental treatment of the fearful patient. It was first discovered by Joseph Priestley in 1772, however, it was not until 1844 when Horace Wells used it as a medical anesthetic. Today, nitrous oxide is used in conjunction with local anesthetic when performing dental treatment on apprehensive patients. Nitrous oxide on its own cannot reliably anesthetize a patient profoundly enough for a patient not to feel a thing. Therefore, it must be used with novocaine to numb the area. Nitrous oxide is administered with pure oxygen and is breathed through a nasal hood. The machine that delivers the gas is a fail-safe machine which will turn off if the oxygen level falls below 35%. Nitrous oxide is not meant to put one to sleep, but merely relax. When given before the anesthetic injection, it can make that part of the procedure much more comfortable. It will put a patient in a state of mild euphoria and will alter the perception of sights, sounds, and time. It also has a mild amnesic effect leaving much less memory of the procedure. Another extremely nice feature of nitrous oxide is that the patient can be flushed with pure oxygen after the procedure and be totally lucid and able to drive home. Nitrous oxide can make a dental appointment a very pleasant experience.