San Diego Center for Oral and Facial Surgery

Wisdom Teeth

Wisdom teeth are technically known as third molars. In the United States third molars are designated numerically as teeth  #1, 16, 17, and 32 (indicated by the red dots above). Third molars usually erupt in the late teens or early twenties. Most people will have to get their third molars removed sometime during their lives because of infection, pathology, impaction, and damage or potential damage to adjacent teeth.

Why do we have wisdom teeth in the first place if we don't need them?

Much like the problematic appendix of the gastrointestinal system, it is proposed that wisdom teeth are byproducts of human evolution and dietary change. The jaws of primitive man were larger than that of modern man; therefore, third molars had enough room to grow in properly. Since raw foods predominated primitive man's diet, third molars were necessary for chewing and digestion.

Although the jaws of modern man are smaller than that of  primitive man, the size of the teeth have essentially remained the same. Therefore, crowding often occurs where third molars develop.

Most people will form all four wisdom teeth; however, variations in the number of wisdom teeth that form among individuals can occur.

What are the reasons for removal of wisdom teeth?

Because of the lack of space for wisdom teeth, a variety of problems can develop. The most common problem is impaction of the wisdom tooth. An impaction occurs when a wisdom tooth fails to erupt normally. A wisdom tooth may be misaligned or simply held up by bone or gum tissue. When an abnormally erupting wisdom tooth is completely encased in bone, it is known as a full-bony impaction; when partially encased in bone, a partial bony impaction; and when encased in gum tissue alone, a soft-tissue impaction. Because of the frequent problems caused by wisdom teeth, the World Health Organization has classified impacted wisdom teeth as pathologic entities.

Abnormally erupting or impacted wisdom teeth frequently cause secondary problems that necessitate their removal. The most common secondary problem is infection. Because of the frequent lack of space for a wisdom tooth to erupt normally, food debris and bacteria can get trapped in spaces around the wisdom tooth that cannot be reached for cleaning. This can lead to infection of the gum tissue overlying the wisdom tooth (pericornitis) or infection of the bone surrounding the wisdom tooth (osteomyelitis). Sometimes the infection can spread to the soft tissues of the face and neck. Infections of the head and neck can become life threatening and frequently  require hospitalization and surgical drainage.

An abnormally erupting wisdom tooth can also cause damage to the tooth in front of it (the second molar). A mesioangular or horizontal pattern of eruption can cause structural damage to the second molar. The destruction can become so severe, that removal of the second molar may become necessary as well. Often, this will necessitate the replacement of the second molar with a dental implant. An impacted wisdom tooth can also cause severe bone loss behind the second molar. This will require a bone graft when the wisdom tooth is removed.

The membrane surrounding an impacted wisdom tooth (known as the follicle) can also transform into a cyst or tumor. Although rare, the consequences of a cyst or tumor in the jaw can be devastating. Since cysts and tumors of the jaw bone tend to grow very slowly, symptoms usually do not occur until damage has occurred. These growths can cause cause permanent damage to adjacent teeth, bone, and nerves necessitating additional procedures or surgery other than removal of the wisdom tooth.

Whether or not wisdom teeth can cause your other teeth to become crowded is a topic of controversy. In general, potential crowding of your permanent teeth itself is not an indication to remove your wisdom teeth. Your permanent teeth can drift or crowd even after your wisdom teeth have been removed. If you have had orthodontic treatment, it is wise to continue wearing your retainer after your wisdom teeth are removed.

To view actual cases click here: Problems Associated With Third Molars 

When should someone get their wisdom teeth removed?

The best time to get your wisdom teeth removed is before symptoms or damage occur. Most people have their wisdom teeth removed in the late teens or early twenties. If symptoms occur, your wisdom teeth should be evaluated for removal immediately. 

It is a known fact that delayed removal of wisdom teeth is associated with a higher frequency of complications (see complications below). Therefore, every person should have their wisdom teeth evaluated by the age of seventeen.

What are the complications of wisdom tooth removal?

Major complications related to the removal of wisdom teeth are rare. However, the degree of risk depends on the individual patient's own anatomy and preexisting conditions. The tables below demonstrate the minor and major complications related to the removal of wisdom teeth. 

When evaluating any surgical procedure one must weigh the benefits of surgery against the risks of surgery. 

What is dry socket?

Dry socket is a painful condition that follows the removal of wisdom teeth. Dry socket or alveolitis occurs when the blood clot is dislodged from the tooth extraction site leaving bare bone exposed. This condition is most common in the lower wisdom tooth area although it can occur following the removal of any tooth. 

Dry socket is more frequent in individuals older than 30. People who smoke or fail to follow post-operative instructions are more likely to develop dry socket. Dry socket may occur 5-10% of the time regardless of taking every precaution to avoid this condition. It is characterized by a throbbing ache that radiates up and down the jaw and frequently into the region of the ear.

Fortunately, dry socket is easily treated. The doctor will wash any debris out of the tooth socket and place a medicinal salve into the socket. Symptoms are relieved rapidly. Dry socket usually resolves after one treatment; however, repeat treatments may be necessary.

Potential Complications Following Third Molar Removal
Complication Risk Factors Prevention Treatment Usual Course
Swelling Prolonged surgery, difficult surgery, unpredictable Intravenous cortisone given just prior to surgery Head elevation, ice to face 20 min on and 20 min off for 36 hours Swelling becomes maximal 3 days after surgery then subsides over the next 5 days
Difficulty Opening Mouth Preexisting TMJ problems or muscular disorders, prolonged surgery, unpredictable Appropriate treatment of TMJ and muscular dysfunction - surgery may exacerbate these conditions Soft diet, gentle stretching exercises, warm moist compresses, anti-inflammatory medications Depends on preoperative condition - usually resolves within 2 weeks - may need further treatment
Stretching of Corners of Mouth Small mouth, dry and chapped lips, cold sores, prolonged and difficult surgery Avoid dry chapped lips, wait until cold sores resolve prior to surgery Keep lips moisturized, antiviral treatment Resolves within 1 - 2 weeks
Bleeding Use of non-steroidal anti-inflammatory medications such as aspirin and ibuprofen, blood thinners and anticoagulants, bleeding tendencies, anatomic variations such as arterio-venous malformation Avoid non-steroidal anti-inflammatory medications prior to surgery, medical management of blood thinners, anticoagulants, and bleeding disorders Appropriate medical or surgical management Light bleeding or spotting of the guaze is expected up to 24 hours after surgery - profuse bleeding from the tooth extraction socket requires immediate attention
Dry Socket Smoking, age over 30, early loss of blood clot from tooth extraction socket following surgery No smoking or sucking through straws following surgery, early evaluation of wisdom teeth Medication applied to socket in office will relieve symptoms

Occurs 5 - 7 days following surgery - resolves after application of medication to tooth extraction socket - may take several applications
Bruising Use of non-steroidal anti-inflammatory medications such as aspirin and ibuprofen, blood thinners and anticoagulants, bleeding tendencies, thin and delicate skin, prolonged and difficult surgery Avoid non-steroidal anti-inflammatory medications prior to surgery, medical management of blood thinners, anticoagulants, and bleeding disorders Warm moist compresses to the face and head elevation Resolves within 2 - 3 weeks
Infection Preexisting infection, smoking, diabetes, immunocompromised states  Smoking cessation, stabilization of medical condition, antibiotic therapy Appropriate surgical management and antibiotic therapy Resolution after three to ten days
Numbness to Lower Jaw, Lip and Chin Roots of lower wisdom tooth overlap or wrap around the nerve of the lower jaw (inferior alveolar nerve), presence of pathology or infection that involves the nerve of the lower jaw Early evaluation of wisdom teeth before roots fully develop and before infection or pathology develop Observation if there is  low suspicion of direct nerve injury - surgical exploration or nerve repair may be necessary in cases of partial or complete nerve injury Resolution of symptoms depends on the degree of injury to the nerve - condition may be temporary or permanent
Bone Splinters Bone splinters or bony sequestrae are common occurrences following tooth removal - a thin shell of bone often surrounds a tooth and a small piece of that shell may die off and work its way out of the gum tissue following tooth removal  None Removal of bone splinter if it becomes infected or irritating May occur days to weeks after tooth removal - resolved once bone splinter is removed or falls out on its own
Jaw Fracture Thin jaw, presence of significant bony destruction due to infection or pathology, abnormally large wisdom tooth Early evaluation of wisdom teeth, avoid potential trauma to the jaw (i.e. contact sports) and avoid hard or chewy foods for 3 weeks following wisdom tooth removal Appropriate surgical management 6 - 8 weeks for jaw fracture to heal