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.
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.
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.
A crown buildup is essentially a large filling that is used to replace enough missing tooth structure to retain a crown (or cap). Most teeth that require a crown (or cap) are broken down due to a large cavity or fractured cusp. Depending on the amount of missing tooth structure, there are times that there is not enough tooth remaining above the gums to allow a crown to grab hold of. Even though a crown is glued on, there must still be enough tooth structure present to provide a friction fit since the glue is not strong enough to bear the brunt of one’s bite.
Teeth that have undergone root canal treatment usually need crown buildups. This is because by the time the inner surface is removed to provide access to the root canal space and the outer surface is removed to provide space for the porcelain, there is not much tooth structure left to retain a crown.
Broken tooth with a buildup
There are different materials available for crown buildups: composite (tooth-colored filling material), amalgam, and glass ionomer. I prefer the glass ionomer because it leaches fluoride into the surrounding tooth structure. This makes the tooth more resistant to decay. This is an important feature since decay sneaking up under a crown can be its achilles heel. A crown that is placed on a properly constructed crown buildup should give a person decades of service.
The gum line (cervical area) is a common location for fillings to be needed. They can be needed due to decay, toothbrush abrasion, erosion, or abfraction. Cavities along the gum line are totally preventable with good oral hygiene on a daily basis. Toothbrush abrasion is another preventable reason for needing cervical fillings. Chemical erosion can dissolve tooth structure. It is most common on any exposed dentin since dentin is significantly softer than enamel and the gum line is where most of the exposed dentin will be. Chemical erosion can come from acidic foods or reflux of stomach acids. Abfraction is thought to be caused by tooth flexure from biting and chewing forces. It is postulated that tiny particles of tooth structure fracture off at the cervical area eventually getting deep enough that it would need to be repaired. There are two types of materials used to restore cervical defects – composite and glass ionomer. Glass ionomer is most helpful in individuals with a high cavity rate. The glass ionomer will leach fluoride into the surrounding tooth structure making those areas more decay resistant. Unfortunately, glass ionomers are not very wear resistant and need to be replaced frequently. The other material that is used for gum line fillings is composite, the one that is normally used for tooth-colored fillings. Since the composite doesn’t leach fluoride, it tends to get small cavities around its edges and must be replaced frequently. The best thing to do is prevention by gentle tooth brushing along the gum line on a daily basis.
Three pins placed in tooth before adding filling material.
Many times, teeth can be so broken down due to extreme decay or fracture that there is not enough tooth structure available to hold a filling in place. In most of these cases, a crown (cap) would be indicated. However, certain situations may call for a change in plans. Things like inability to afford a crown, an unstable gum situation, waiting to see if a recent root canal will work, or any situation where the long term progression (outlook) is questionable are all possible reasons to go with just a filling. When there is not enough tooth structure to hold a filling, then pin retention is indicated. Pins are tiny threaded screws that are placed about ½ millimeter into dentin. A pilot hole ever so slightly smaller than the pin is drilled into the tooth, then the pin is screwed into place. An amalgam (metal) or composite (tooth-colored) filling is then placed over the top. The pin is only used for retaining the filling on the tooth. It does not reinforce like a rebar does with concrete. Pins have been known to cause microcracks in the dentin, however, I have not seen a fracture of the underlying tooth structure that was severe enough to lose the tooth that was caused by the pin alone.
Once root canal treatment has been performed then the tooth must be restored. Root canals are usually performed on teeth that are quite broken down and therefore must be built up to have enough tooth structure available to hold onto a crown. In order to retain the core buildup, many times a post must be placed inside the root canal. This is done by removing a portion of the root canal filling material (the part closest to the tip of the root is left to seal the end) and drilling out the proper size to accept the post (no need to worry about the drilling – remember there is no nerve in a root canal tooth). Then, the dentist chooses one of two types – a cast post and core or a prefabricated post. The cast post and core has advantages in that the core buildup is made as one piece with the post so there is no way for the two to separate. A disadvantage is that it must be fabricated outside of the mouth and therefore cannot be cemented on the same day, however, other provisions must be made to build up the tooth. Some prefabricated posts are metal and some of the newer ones are made of carbon fiber composite. The newer carbon fiber ones have a little bit of give to them and they look promising on possibly reducing root fractures in teeth with posts.
Sealants are coatings that are placed on the chewing surfaces of teeth. Their placement can save literally thousands of dollars over the course of a lifetime. To place a sealant, the dentist or assistant will clean all of the plaque off the tooth. This can be done with a traditional prophy cup, just like one used when getting ones teeth cleaned, or by air abrasion, kind of like a mini-sandblaster. Then, an acid solution is placed in the chewing surface. This will etch the enamel surface of the tooth. The enamel has a frosty appearance but microscopically, there are huge crevasses created when the acid dissolves away some of the mineral content of the tooth surface. It is this microscopic layer that is responsible for the retention of sealants. At this point, the acid is thoroughly rinsed off and a liquid plastic is flowed over the surface. An extremely intense light beam is placed over the area which hardens the plastic. The liquid has flowed into the microscopic crevasses and is not hardened in such a way that the sealant “adheres” to the tooth. Sealants are used only on the chewing surfaces to seal the tiny pits and fissures that are very susceptible to cavities. It will not seal in between the teeth or at the gum line. By placing sealants at an early age when the teeth are most susceptible to decay, it can help prevent cavities. Once a cavity is in place, it will have to be maintained over a person’s lifetime, necessitating multiple re-fills and many dollars spent. That is why it is best to place the sealants on children.
As a dentist it is my moral and ethical obligation to tell my patients to brush their teeth. It is always a pleasure to see patients who take good care of their teeth. It is especially gratifying when we see a patient whose home care was far from sterling, but has gotten on the wagon and started brushing regularly. The problem is that some people get too much of a good thing. By being over-zealous with the toothbrush, one can damage their teeth and gums. We used to be taught to brush as hard as we could. That is reminiscent of the good old days when the bristles were made of natural materials. Once these bristles came in contact with saliva, they would soften, thus, more force could be applied without causing damage. Now the bristles are made of nylon which doesn’t soften when moistened. Therefore, vigorous scrubbing with a toothbrush can wear away gums and tooth. The gums will first recede due to the abrasion which can cause tooth sensitivity at the exposed root. Next, since the dentin (inner layer of the tooth) is much softer than enamel and it is now exposed to the brush because of the receded gums, it will wear away in a saucer like fashion at the gum line. This will require a filling to correct the damage. The better thing is prevention. Don’t overdo it on the force placed on a toothbrush. Plaque is not that difficult to remove with gentle brushing.
A chipped front tooth can be a very unsettling thing for a person of any age. Before the bonding era, the tooth would have to be whittled and a crown (cap) placed. Now, front teeth can be restored to the point where the repair is virtually imperceptible. The tooth is first cleaned up and any rough edges are smoothed. A long bevel is prepared on the enamel surface to increase the amount of enamel that is available for bonding. Then, an acid solution is applied to the surfaces. After rinsing, thousands of microscopic crevasses are present. Although they are very tiny, these areas allow for a liquid plastic to be flowed into these crevasses then hardened with an intense light source. This alone is adequate to retain the repair in place for a number of years.
Dr. Gangwisch Repaired This Tooth With Bonding
A composite (tooth-colored filling material) is then color matched with the remaining tooth. It is built up in multi-colored increments in order to mimic nature. Each layer is light hardened, then it’s time to contour and polish the restoration. The resulting filling looks great when it is finished. With proper care, this repair can last five to ten-plus years. Since it is not as durable as porcelain, one must be careful not to bite on hard things with it. The tooth may eventually require a crown, but repairing a chipped front tooth with a bonded filling can be a conservative, less-expensive alternative.
Once a root canal has been completed, it is extremely important that the tooth be properly restored. If not, then there would be a good chance that the tooth could be lost permanently. The reason for this is the dental pulp which houses a collection of nerves and blood vessels in the center of the tooth will bathe the inner tooth layer (the dentin) with fluid, allowing the tooth to flex under load. Once the source of the moisture is gone, the tooth becomes very brittle. I always recommend that all chewing teeth have a crown placed soon after a root canal has been completed. I have even had the unfortunate experience of needing to extract a tooth only weeks after root canal treatment due to the tooth fracturing through to the root because it had not been properly restored yet. Some front teeth, if they have adequate remaining tooth structure, can be restored with just a filling.
Crown Over Root Canal Tooth
To place a crown on a back tooth, usually a crown buildup needs to be done. A crown buildup is a core of filling material that is used to replace the tooth structure that was lost in the root canal process and due to decay. This core may need to be retained with pins or a large post that is placed in one of the canals. With a quality, well-timed final restoration covering and protecting a root canal tooth, that tooth should give decades of future service.