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Teeth

Avulsion injuries

Alternate phrases: Child tooth fell out; Lost tooth; Missing tooth; Tooth fell out; Tooth knocked out; Tooth loss.

Teeth may be lost for several reasons. First, they can be avulsed (knocked out) from trauma. If the avulsed tooth is a permanent tooth (or if you're not sure), call a dentist immediately. If a tooth has been out of the mouth more than an hour, the possibility of re-planting it successfully drops off dramatically.
Learn more: Glossary › Primary tooth

If you are not sure if the tooth is a permanent tooth, don't try to replace it in the tooth socket. If the patient is unwilling or unable to cooperate to allow replacement of a permanent tooth in its socket, and the tooth must be transported outside the mouth, you can place it in a container of Hank's Balanced Salt Solution (available at most pharmacies, and often kept on hand by athletic trainers) or milk. Do not use soap or other solutions on the tooth root.

Avulsion of Permanent Teeth (Incompletely & fully developed)

Permanent teeth which have been traumatically displaced completely out of the jaw have a high incidence of inflammatory resorption and replacement resorption after they are replanted in the jaw. This is mainly caused by damage to the living cells of the tooth's periodontal ligament. Following replantation of the tooth, if the ligament fibers are not viable, the cementum of the tooth may fuse directly to the bone. Bone normally undergoes physiologic resorption and replacement throughout life.

If a tooth fuses to bone following an injury, the "osteoclast" cells which dissolve away existing bone, and the "osteoblast" cells which deposit new bone will do the same to the tooth—except osteoblasts are incapable of forming tooth structure, so they replace it with bone. This process is known as "replacement resorption." Over time, the tooth's root can be completely dissolved and replaced with bone.

It is also possible that the body's inflammatory reaction to trauma can produce acids and enzymes which dissolve the tooth. This is known as "inflammatory resorption", and the process may rapidly destroy the tooth's root after replantation.

Minimizing the possibility of root resorption means minimizing damage to the periodontal ligament. To accomplish this, it is important to return the tooth to its bony socket as soon as possible after the avulsion injury. Teeth which have been out of their socket more than an hour have a drastically reduced chance of long term survival.

To minimize periodontal ligament damage, the avulsed tooth should not be handled by its root. Any dirt or debris on the root should be removed by rinsing the tooth with lukewarm tap water. The root should not be scrubbed. If the patient is cooperative and can tolerate having the tooth replaced in the socket, that is the preferred next step. If the patient is uncooperative, the tooth should be transported to the dentist in milk or in Hank's balanced salt solution (available at most pharmacies, and commonly kept on hand by athletic trainers). The tooth should not be rinsed with soap, saline, contact lens solution or other substances.
Learn more: Glossary › Periodontal ligament

It is important to see a dentist immediately following avulsion of a tooth. The dentist will generally place the tooth in the socket as described, if it has not been done already. He or she will generally place a "functional splint", consisting of a flexible wire bonded to the avulsed tooth. This allows the tooth to have some mobility, while being firmly retained in place in the mouth.

Common Treatment of Fully Developed Permanent Teeth Which Have Been Avulsed

For fully developed permanent teeth (i.e. the root is completely formed), the splint is usually left in place for approximately a week to ten days. After about a week, the tooth's root canal is accessed, and medical grade calcium hydroxide is placed inside the tooth to prevent inflammatory root resorption from occurring. Endodontic (root canal) treatment of the tooth outside the mouth is generally discouraged, because it prolongs the out-of-mouth time, and risks manually damaging periodontal ligament tissue, the survival of which is key.
Learn more: Glossary › Inflammatory resorption
Learn more: Procedures › Endodontic treatment

Treatment of Incompletely Developed Permanent Teeth Which Have Been Avulsed

For incompletely developed permanent teeth (i.e. the root is not completely formed), there is some chance that the pulp may remain vital. The same precautions apply to the periodontal ligament, regardless of whether the tooth is fully formed or not. Replanting the tooth in its socket as soon as possible after the injury remains critical to preserving the vitality of the periodontal ligament. Applying a flexible splint is still generally done; however, it is usually left in place a bit longer (e.g. two weeks) to give the blood vessels and nerve tissues at the root tip adequate time to reattach (in medical terms, "reanastomose") to the still-living tissues inside the tooth. Close follow-up to rule out pulp death (necrosis), infection, and resorption will be necessary for the injured tooth.

Rigid splinting is generally discouraged following replantation of avulsed teeth, because it can encourage ankylosis (fusion) of the tooth to the bone. Allowing some mobility discourages ankylosis and allows the fibers of the periodontal ligament to reattach and resume their normal function.

Avulsion of primary teeth

Baby (primary) teeth normally begin to loosen and exfoliate (fall out) around age six. Normally, the lower front teeth are lost first, followed by the upper front teeth about a year later. If any of the front six primary teeth are avulsed (knocked out completely), do not try to replace it in the mouth. Generally, the dentist will not replace the tooth in its socket either, unless there is no permanent tooth in the jaw beneath it. An X-ray image is necessary to determine this.
Learn more: Glossary › Tooth loss, primary
Learn more: Procedures › Radiographs

If a primary tooth is avulsed, there is a chance that the permanent tooth developing under it may have been injured. If damage has been done to the developing permanent tooth's crown, it will often not be evident until that tooth erupts into the mouth a couple of years later. The most common complication is a discolored spot where inflammation dissolved away a portion of the permanent tooth's crown.

Treating it is generally straightforward, and can be accomplished by bonding of composite resin filling material, or placement of a veneer. Sometimes discolored spots can be bleached when the patient is older (assuming it has not already been treated with a filling or veneer). Eruption of the permanent tooth may also be delayed by a year or two due to the development of extra fibrous connective tissue when the primary tooth is lost prematurely.
Learn more: Glossary › Bonding
Learn more: Glossary › Composite resin
Learn more: Procedures › Bleaching
Learn more: Procedures › Veneers
Learn more: Diagnoses › Enamel hypoplasia

A tooth may also be lost as a result of a fracture or decay (caries) which renders the tooth unrestorable. It can also be lost as a result of destruction of the tooth supporting bone from periodontal disease. Loss of multiple teeth is known as partial edentulism. Lost of all the teeth is called complete edentulism.
Learn more: Diagnoses › Caries
Learn more: Diagnoses › Cracked teeth
Learn more: Diagnoses › Edentulism
Learn more: Diagnoses › Periodontitis