Cysts 

Aside from pericoronitis, there are two  other complications associated with impacted wisdom teeth.  They both  involve the uncontrolled expansion of the follicle (the space in the bone where the tooth was originally formed). This follicle is lined with cells which are supposed to transform into the lining of the sulcus of the gums when the tooth erupts.  But if they are kept submerged for too long, they sometimes forget their original mission and begin to produce fluid which expands the follicle causing a cyst.   

These cysts can become very large and cause distortion of the bone and face, and can lead to such weakness in the bone the jaw may be prone to fracture.

Amyloblastoma

A rare complication arising from uncontrolled follicular growth is a form of tumor called amyloblastoma. This tumor is not considered a cancer because it does not tend to metastasize (spread to other areas of the body), but it is locally invasive which means that it grows uncontrollably and can cause major damage and weakness in the bone if it is not thoroughly removed.  Amyloblastoma is most likely to attack young adult males. It is less frequent in females or older people of either sex.  Since it is always associated with an impacted tooth, usually a wisdom tooth, (but not always, as seen in the images above)  it rarely occurs before the age of 18.  It is difficult to remove entirely, and the surgeon will usually perform a wide excision (ie. he takes a lot of extra bone along with the tumor) just to be sure that he has removed it all.  

Do ALL extracted teeth HAVE to be replaced?

The short answer is NO!  The removal of any tooth has consequences, some of which are important enough to cause you to seriously consider replacing that tooth with a removable or fixed alternative.  If it's one of your top front teeth, then esthetic considerations will probably cause you to want to replace it.  But even then, if you don't care about how you look, leaving the space will not kill you.  The x-ray below shows what happens to the adjacent teeth if a first molar is extracted when a patient is very young.  There IS tilting of the teeth and a small collapse of the occlusion, but it is not especially obvious when you look at the teeth in the mouth.

I am going to guess that at least a third of my adult patients have lost back teeth in the past and have never had them replaced.  A vast majority suffer no major problems eating, speaking or esthetically (The way they look).  On the other hand, a few, especially some women, tend to develop the joint problems, headaches, neck aches or ear aches typical of TMJ.  If they use a lot of sugar, they are more prone to ectopic decay (explained below). In addition, many of these people who later want to repair the damage caused by the loss of the tooth find that repair is much more expensive because of the movement in the adjacent and opposing teeth.

• The removal of any tooth will always cause destabilization of the remaining teeth and over a period of years, every tooth in your mouth will move in response to its loss, at least a little.  The amount of movement depends upon several factors:

  • Your age: The younger you are when the tooth is removed, the more quickly and severely the rest of your teeth will move in response.  

  • The position of the tooth in the mouth:  The loss of any back tooth (the canine tooth and behind) will have a greater effect on the movement of the remaining teeth than the loss of a front tooth.  The removal of the last tooth in the arch will not effect the position of any tooth in front of it.  It may, however allow hypereruption  ("extrusion") of the tooth above or below the missing tooth if that tooth does not make contact with a tooth in the opposite arch. Finally, the majority of the movement in the remaining teeth happens on the same side as the missing tooth.  Teeth on the oposite side of the dental arch are effected, but not nearly as much.

  • Bruxing (grinding or clenching the teeth): If you brux your teeth, then the movement is more severe and happens more quickly than if you do not brux.

• The image to the right shows the effect of the removal of a lower first molar.  

  Note that the tooth behind the space has leaned forward into the space vacated by the extracted first molar.  This movement tilts the biting surface of that tooth downward and therefore allows the tooth directly above the space (the top first molar) to begin to extrude down.  Because of the way this tooth is shaped, the downward movement of the top first molar opens up some space between itself and the teeth on either side of it.  This newly created space allows the adjacent teeth to move and tilt as well causing a discrepancy in the curvature of the arch form.  The image on the left shows a fairly typical situation in which a upper first molar was removed, probably before the age of twelve.  The upper second molar has tilted forward closing the space vacated by the extracted first molar.  At the same time, the misaligned biting surface on the second molar has caused a similar discrepancy in the position of the lower second molar.  Less apparent in this image is the decrease in "vertical dimension" (the space between the top and the bottom jaws) on that side.  This produces a misalignment in the position of the ball joint of the lower jaw leading, in some cases to TemporoMandibular dysfunction.

  The early loss of back teeth has five consequences:

  1. It stimulates bruxing which leads to TMJ.

  2. It tends to "collapse the occlusion" ( decreases the vertical dimension) which means that the Jaw on that side must close a bit further in order to get the teeth to touch.  This pushes the ball joint of the jaw further into its socket causing injury to structures within the joint.

  3. The tilted angles of the biting surfaces means that biting forces are no longer parallel with the long axis of the tooth (straight up and down the root of the tooth.  This puts extra pressure on the bone which supports the tooth and tends to cause loss of the bone.  This is a localized form of gum disease that over a period of years may ultimately lead to the loss of the tilted teeth.  

  4. The tilted and extruded position of the teeth place the contacts between these teeth and the adjacent teeth in unusual positions.  The contact between the teeth is the place where decay is most likely to occur because it is a place where plaque tends to build up.  Decay in unusual positions on the teeth is called "ectopic caries", and it is generally quite difficult to repair without striking the nerve.  When this happens, it becomes necessary either to extract the tooth or to perform a root canal procedure in order to avoid a toothache.  

  5. It makes it more difficult and expensive to replace the missing tooth later due to the poor position of the surrounding and opposing teeth. 

• Note that the loss of a back tooth, even if there are more teeth behind the space, does not always lead to the leaning and extrusion of the remaining teeth.  If all of the teeth adjacent to the extracted tooth, as well as all teeth in the opposite arch make firm, stable contact with teeth in the opposing arch, and as long as at least half of the occlusal table (the top, chewing surface) is in stable contact with teeth in the opposing arch, then there is little likelihood of major tooth movement.  This is especially true if the patient does not tend to have bruxing (grinding and clenching) habits.  

Broken Jaws

Yes, it does occasionally happen. The fracture of a lower jaw is unusual, principally because dentists who extract teeth routinely do not place great force on any instrument to remove a tooth.  Teeth are generally "finessed out" with a minimum of pressure applied to the jaw through the surgical instruments.  There are, however, some situations in which a dentist can look at the x-ray and see that the jawbone that surrounds the tooth is much more fragile than is usually the case, and will usually warn the patient that fracture of the jaw is a possibility.  People are not like cars, every one identical.  Everyone is unique and presents unique circumstances under which the dentist must labor.  The chances that the removal of any given tooth will result in a fractured lower jaw run about the same for any dentist who attempts the extraction.  That particular patient is usually more prone than other people to a broken jaw due to any traumatic incident such as a traffic accident or a blow to the jaw during a sporting event. Unfortunate, but true, and a fact of life for any dentist who extracts teeth.

Sinus perforation

The image to the right is a detail from a panoramic film.  The roots of the upper back teeth are always in close approximation to the maxillary sinus.  Since everyone is built differently, The roots of the teeth may actually appear to be inside the sinus.  There is always a thin wall of bone between the root and the sinus, but is can be very thin indeed.  Most of the time, the bone remains intact, but upon occasion, a piece of the bone separating the root from the sinus may break off and be removed with the tooth.  This creates a direct connection between the sinus and the mouth!  That means that you would be unable to suck on a straw, because air would rush into your mouth from your nose through the socket.

Sometimes a sinus perforation will go unnoticed by the dentist or the patient.  If the perforation is small, the only symptom could be a nosebleed.  If this happens, call the dentist so he can prescribe the proper drugs so that healing can proceed normally

When a sinus perforation occurs, the dentist will prescribe an antibiotic to prevent infection and a decongestant to keep the sinuses clear during healing.  The patient bites on his gauze as is usual after any extraction, and a clot will form in the socket as usual.  If nothing disturbs the clot, it will organize during healing and close the perforation.  Dry sockets rarely happen after extraction of upper teeth unless the patient smokes.

• It is IMPERATIVE, however that the patient do NOTHING that could disturb the clot.

• Do not suck on anything for at least a week. This puts pressure on the clot and could dislodge it into the mouth.

• Do not smoke...the longer you wait the better.  This will dissolve the clot, or could even suck it out of the socket.

• Do not blow up balloons or anything else.  This puts pressure on the clot and could dislodge it into the sinus.

• Avoid sneezing. This explosive event will definitely dislodge the clot.  

In the case of very large perforations, or in case the clot dislodges and a perforation between the sinus and the mouth remains after healing, It may be necessary to perform a further surgical procedure in order to draw a flap of gum tissue over the perforation to close it permanently.

Sequestrii

(Broken bone fragments that come out weeks after the extraction, but are often mistaken for pieces of tooth.) 

Whenever a dentist extracts a tooth, it requires that the bone that used to hold the tooth be expanded, or sometimes even fractured to allow the tooth to slip out of the socket.  Most of the time, these fractures are of the type known as "greenstick" fractures which means they are only partial fractures immediately around the top of the socket leaving the bone fragments still attached to the main body of the bony structure beneath.  In some instances, these greenstick fractures coalesce to release a bone fragment completely from the underlying bony structure.  Even when this happens, the bone fragments tend to heal and reattach to the main body of the bone during healing.  

In the oral cavity, however, the presence of oral bacteria, as well as noxious chemicals from the foods we eat and cigarettes we smoke can cause the healing to cease.  This is what causes dry sockets.  Bony fragments that do not heal properly often loose their blood supply and become "necrotic" (dead tissue).  Thus, the body begins the process of ejecting them from the healing socket, a process known as sequestration.  The process can be painful, and sometimes requires the dentist to reenter the socket to remove the sequestrum.  When the sequestrum comes out on its own, the patient often mistakes this piece of bone for a piece of tooth that the dentist left in the socket.

Sequestrii are a normal complication of extractions.  They are often unavoidable, and undetectable at the time of the extraction.  They are not considered to be a mistake the dentist made.  Once the sequestrum is gone, the healing resumes, the pain subsides and all is well.

Retained roots (Pieces of tooth left in the bone by the dentist)

A large majority of teeth are removed in one piece when they are extracted by the dentist.  However, many do break leaving one or more fragments of varying size in the bone.  The dentist must decide at the time of the extraction whether or not to remove the remaining tooth fragment.  In most instances, it is NOT essential to remove every root fragment that is left in the bone!!  Retained root tips will generally simply heal in place and never cause a problem to the patient after healing.  In the few cases in which the root fragment is rejected by the body, it generally sequesters out of the socket like an ordinary bony sequestrum.  The dentist must weigh the relative benefits of removal of the root tip versus the complications that the removal will cause the patient.  Often, the removal of the offending root fragment necessitates quite a bit of drilling of bone and heavy duty prying, not to mention quite a bit of time.  This always results in a much greater degree of pain for the patient during healing. It also increases the likelihood of a dry socket, which is a painful result that most people would rather do without.  On the other hand, leaving the root tip in place causes no further difficulties to the patient most of the time.