These are the primary reasons a particular dental restoration might be recommended for the treatment of a specific tooth. There are no "hard and fast" rules about what follows. Recommendations may vary according to your oral hygiene habits, complicating factors such as bone loss or receded gums from periodontal disease, medications or conditions that alter your saliva flow and decay susceptibility, or changes you desire in appearance. The decisions as you can see are mainly "engineering" ones, based on the amount and quality of the remaining tooth structure associated with the chewing points of the teeth and their ability to withstand the tremendous forces associated with crushing our food.
Sealant -- A sealant is not so much a restoration as it is a way to avoid the need for one. It is used to prevent decay in grooves and pits that form naturally on teeth as they grow. Because these places are too small to be cleaned by your toothbrush, they must be eliminated or eventually the bacteria will win. To prevent the fillings and crowns of tomorrow, we clean the teeth by a variety of methods and flow a tough sealing material into the defects, eliminating the "non-cleanable" place.
Filling -- This is the most often performed procedure for the repair of a decayed tooth. It is done when the resulting hole created by the removal of the soft, infected tooth matter and any existing filling adjacent to it does not severely compromise the functional strength of the tooth, and where the forces of biting will not cause the material itself to fail. In other words, you are most likely able to chew on it without the tooth or filling breaking. A filling does not strengthen a tooth; it only seals a hole - like a cork in a bottle. Cracking or breaking of teeth is to be avoided because it often necessitates a crown and root canal therapy. Sometimes it makes a tooth not salvageable.
We do not use silver/mercury fillings in any case --for three reasons:
#1 is the fact that the dentist has to remove additional healthy tooth structure beyond the decayed part to do those fillings properly (further weakening the tooth).
#2 is the fact that even though the research shows no harmful effects from having this mercury based compound in your mouth; I still don't see it on the list of nutrients they add to my Total cereal.
#3 is the fact that the stuff ends up in the environment someday. A very large fraction of the mercury in the waters of the world comes from dental sources (waste water from dental offices, cremations of folks with silver/mercury fillings, and other equally distasteful things) and many nations of the world are on the verge of outright banning the stuff because it gets into the water sources. I would just as soon not contribute to the "unsafe tuna fish problem".
Inlay -- This is often the answer when the resulting "hole" is such that the remaining tooth structure cannot support a direct filling with any reasonable certainty, or if the hole is such that a filling could not be inserted into the tooth in the mouth without itself becoming a source of problems. This is basically a filling restoration that is created outside the mouth in our dental laboratory and then bonded to the tooth at a second appointment. It is often used when placing a direct filling material would itself add additional strains to the already decay-weakened tooth, or when a filling material does not have the strength on its own to perform the task of chewing for any extended period and something stronger that is fired in an oven is needed.
Onlay -- When the remaining healthy tooth structure becomes too weak to resist the normal forces of chewing over any length of time, or when chewing points are missing, cracked, lost to decay, or broken off, an onlay is used to restore both the form and the biting strength of the tooth. It does this in the most conservative possible manner, and is most often used on back teeth. The easiest way of thinking of this restoration is a "new chewing surface on the tooth" – like a re-treading of the tire.
Veneer -- These are essentially onlays for the front of teeth where appearance is critical but they do not yet require a full cap or crown. They are made of porcelain materials that are both beautiful and strong, and may also be used to give you a great new smile in two appointments. Commonly used for a smile makeover, they also serve well to reshape teeth that may be malformed, have gaps between them, or have broken edges or discolorations and are otherwise healthy.
Crown -- This is the same as a "cap" or "jacket". Think of it as a thimble that fits over the tooth and holds it together. Crowns are used when the remaining tooth structure is severely compromised, malformed, or broken down. They also serve where there is a particularly severe need to strengthen the tooth (such as after root canal therapy on back teeth), where the need to alter the shape or appearance cannot be accomplished in other ways, and where it is necessary to completely cover the tooth with a decay- proof substance. For teeth that have nearly no structure left above the gum-line, we can often combine a foundation restoration (core buildup) with a crown and save a tooth that would have otherwise been slated for extraction.
Gold Dentistry -- Most every restoration has a choice of materials available. The "old reliable" is gold. Because it can be fitted to the tooth with great precision and will not break if you bite on a rock or something by accident (tooth-colored materials are like natural tooth structure in that they can chip or break from impact injury), if the tooth is not normally visible, or you do not mind a little twinkle of gold in your smile, it is still the material of choice for longevity. Patients who desire to minimize the time and expense of dentistry in the future may wish to consider gold restorations. These are used on back teeth for the most part (except for hip-hop rap musicians), and are no more expensive than the tooth-colored equivalent. Many of these provide a lifetime of service. I still clean my mother's teeth with the gold inlays my father did in dental school back in the 1940's!!
Most folks' treatment is best served with a combination of these various restorations. The costs generally increase from the sealant through the inlay, onlay and crown. Without early detection of failure or if needed decay treatment is delayed, the repair needed will usually follow the same sequence. I make the best judgment I can as to the exact treatment needed in each case. If new information comes to light during a procedure, such as a hidden crack under an old filling or decay extending deeper than expected, I will always advise you of any suggested alterations in your treatment plan before doing it.
- Dr. Bob Knudson