Cracks can occur in the crown or the root of a tooth. Cracks in teeth are very difficult to restore. If the crack is limited to the crown of the tooth, placing a crown (cap) on the tooth may protect it from further extension of the crack. If the root of a tooth is cracked, in most cases the tooth cannot be restored and must be extracted. Teeth restored with fillings or teeth that have undergone root canal treatment are more susceptible to cracking. Habits, such as chewing ice, clenching and grinding can also contribute to cracked teeth.
Cracked teeth can present with several different symptoms. You may feel pain when chewing or pain when the tooth is exposed to extreme temperature changes. When chewing, the pain usually occurs when biting pressure is released. Many times the pain will come and go, making diagnosis difficult. Cracks in teeth can be very difficult to detect, even with x-rays, but early diagnosis is important to maintaining the tooth.
When the crack opens and closes within the tooth, the nerve of the tooth may become irritated. Fluid may also enter the nerve canal of the tooth through the crack, causing damage to the nerve tissue. The nerve damage may become irreversible and endodontic or root canal treatment may be required. In some situations, the tooth may need to be extracted.
The success rate for endodontic treatment is very high. Occasionally, endodontically treated teeth do not respond to treatment and require retreatment.
Some reasons for endodontic failure may include:
It is possible to retreat an endodontically treated tooth by removing the filling material in the roots and reshaping and refilling the canals. It may be necessary to perform endodontic surgery, if retreatment is not an option or is unsuccessful.
Steps in root canal therapy:
Root canal therapy is a procedure where the pulp of the tooth is treated so that the natural tooth can be maintained. The pulp tissue, which contains blood vessels, nerves and connective tissue, is vital to the development of the tooth. Once the tooth is formed, the function of the pulp is sensory.
The tissue of the dental pulp can be subject to irritation or injury caused by deep cavities, trauma to the teeth, tooth cracks, chemical or thermal damage. The pulp can become inflamed. If it cannot repair itself, the pulp needs to be removed, the canals shaped and the space sealed, so that bacteria is prevented from gathering and causing infection.
There are a number of situations where root canal therapy is indicated. If a tooth is sensitive to touch or biting pressure, sensitive to heat or displays swelling in the gums, root canal therapy may be indicated. There are also occasions when there is no pain associated with the need for treatment.
If the nerve in the root is damaged, bacteria may gain entry to the nerve and cause an infection. White blood cells, that fight infections, cannot access this space and bacteria will infect the entire pulp.
If the nerve is not treated, pain and swelling may result. Infection can continue and cause destruction of surrounding bone, forming an abscess. Continuing destruction may result in loss of the tooth.
The success rate for endodontic is approximately 95%. More than 14 million root canal procedures are done yearly. If a tooth requiring endodontics is left untreated, bone loss and infection can occur. This may be very painful. This tooth may be replaced with a bridge or dental implant. But these options may be more expensive and time-consuming than treating the offending tooth.
Root canal therapy is a way to retain teeth that may otherwise require extraction, allowing you to eat the food you want and have a healthy smile.
There are a number of different types of cracked teeth.
Craze lines are small breaks in the enamel or outer surface of the tooth. These cracks are shallow and cause no pain. No treatment is required for this condition, unless it is desired for esthetic purposes.
These cracks occur when a cusp is weakened and fractures away from the tooth. If the fractured cusp is loose and has not come off, the cusp usually needs to be removed. If the nerve in the root of the tooth is not involved, treatment usually involves placing a crown on the tooth. If the nerve tissue has become exposed, root canal treatment may be required followed by a post, core and/or crown.
This type of crack is limited to the crown of the tooth, but may extend to or below the gum line.
If this type of crack is treated early, a crown may be sufficient treatment. If the pulp has been irritated or the crack is extensive, root canal treatment may be required, followed by a post, core and/or crown.
This type of crack extends from the crown of the tooth into the root structure and usually involves loss of the tooth. It may be possible, with a multi-rooted tooth, to section the tooth, perform root canal treatment, and then crown the remaining portion of the tooth.
These cracks begin in the root and extend to the chewing surface of the tooth. These types of fractures have few symptoms. They are usually diagnosed once bone loss is evident on an x-ray film. Treatment is usually extraction of the tooth. In some cases, a part of the tooth may be maintained by sectioning the fractured part of the tooth, performing root canal treatment and restoring with a crown.
Endodontic (root canal) treatment is generally successful. In the rare cases when root canal treatment fails, it may be possible to save the tooth with a minor surgical procedure (root canal surgery).
Endodontic surgery may be needed because of chronic infection, root anatomy variations or calcifications, or to repair root perforations.
One of the most common endodontic surgical procedures is an apicoectomy. This is an in-office procedure where the root tip of the tooth is treated. The area around the tooth is anaesthetized with a local anaesthetic. The root tip of the tooth is exposed. If there is any infected tissue around the root end, it is removed so that healthy bone can then grow in around the root. If the root end is not adequately been sealed, a small filling can be placed at this time. It may take a number of months before the bone completely heals around the root end.
A hemisection or root amputation are other types of surgery that can be done on root canaled teeth. A hemisection is when one root of a lower molar, which has two roots is removed. A root amputation is when one of the three roots of an upper molar is removed. These procedures are performed on multi-rooted teeth where one root cannot be treated with root canal therapy but others have been successfully treated. A hemisection or root amputation may also be required if there is extensive bone loss around one root. These procedures leave a smaller tooth in the original tooth space. Your dentist will discuss options to fill this space.
As in most surgical procedures, no guarantees can be given as to the results of the treatment but endodontic surgery is an excellent opportunity to save your tooth.