What Is The Third Molar Tooth

The third molar, commonly known as the wisdom tooth, is the last tooth to erupt in the oral cavity. Its development and eruption often become a topic of discussion due to potential complications. Understanding the third molar involves delving into its anatomy, development, common problems, and management options.

Anatomy of the Third Molar

The wisdom tooth shares the basic anatomical structure with other molars, consisting of a crown and root. However, it exhibits considerable variation in size, shape, and number of roots. Here's a breakdown:

• Crown: The crown is the visible part of the tooth above the gum line, covered with enamel. The third molar crown generally has four cusps but can vary.

• Root: The root anchors the tooth to the jawbone. Third molars typically have two or three roots, which can be fused or curved, making extraction challenging. The roots are often shorter than those of the other molars.

• Pulp: The pulp is the innermost layer containing nerves, blood vessels, and connective tissue.

The location of the third molar is at the very back of the mouth, in the upper and lower jaws. Its proximity to the mandibular nerve (in the lower jaw) and the maxillary sinus (in the upper jaw) contributes to potential surgical complications.

Development of the Third Molar

The development of the third molar is a lengthy process, starting in early childhood and often not completed until early adulthood. The process follows these stages:

1. Initiation: The tooth bud forms within the jawbone during early childhood, typically around the age of 7-10 years.

2. Crown Formation: The enamel and dentin, which form the crown, begin to develop. This stage usually occurs between 12 and 16 years of age.

3. Root Formation: The root develops after the crown is fully formed, usually between the ages of 17 and 21.

4. Eruption: Eruption happens when the tooth emerges through the gum line into the oral cavity. This commonly occurs between the ages of 17 and 25, hence the name "wisdom tooth" as it erupts when a person is presumably older and wiser.

However, the eruption process is not always straightforward. Many factors, such as jaw size, tooth position, and genetics, can affect whether a third molar fully erupts or becomes impacted.

Common Problems Associated with Third Molars

Many individuals experience issues with their third molars, which may require intervention. The most common problems include:

• Impaction: This is when the tooth is blocked from fully erupting through the gum line. The tooth may be partially or completely trapped in the jawbone. Impaction can cause pain, infection, damage to adjacent teeth, and the formation of cysts or tumors. There are different types of impaction:

  • Mesial Impaction: The tooth is angled forward towards the second molar. This is the most common type of impaction.
  • Distal Impaction: The tooth is angled backward away from the second molar.
  • Vertical Impaction: The tooth is in a normal upright position but lacks space to erupt.
  • Horizontal Impaction: The tooth is lying completely on its side.

• Pericoronitis: This is an infection of the soft tissue surrounding a partially erupted third molar. The flap of gum tissue (operculum) covering the tooth can trap food particles and bacteria, leading to inflammation and infection. Symptoms include pain, swelling, difficulty opening the mouth, and bad breath.

• Crowding: If the jaw is not large enough to accommodate the third molars, they can push against the adjacent teeth, causing crowding and misalignment. This can undo previous orthodontic treatment and affect the bite.

• Damage to Adjacent Teeth: Impacted third molars can exert pressure on the roots of the second molars, leading to resorption (the gradual breakdown of tooth structure). This can weaken the second molar and potentially lead to tooth loss.

• Cyst Formation: In some cases, a dentigerous cyst can form around the crown of an impacted third molar. This fluid-filled sac can enlarge and cause bone destruction, potentially leading to more serious complications.

• Tumor Formation: Although rare, tumors such as ameloblastoma can develop around impacted third molars. These tumors can be aggressive and require extensive surgery to remove.

Diagnosis of Third Molar Problems

Diagnosis of third molar problems typically involves a clinical examination and radiographic evaluation. The dentist will assess the position of the teeth, the surrounding tissues, and any signs of infection or pathology. Common diagnostic tools include:

• Clinical Examination: The dentist will check for signs of inflammation, swelling, pain, and limited mouth opening. They will also evaluate the alignment of the teeth and the amount of space available for the third molars to erupt.

• Panoramic Radiograph (Panorex): This X-ray provides a broad view of the entire mouth, including the teeth, jawbones, and surrounding structures. It helps determine the position of the third molars, the presence of impaction, and any associated pathology.

• Cone-Beam Computed Tomography (CBCT): This 3D imaging technique provides detailed images of the teeth and surrounding structures. CBCT scans are helpful in assessing the proximity of the third molars to vital structures such as the inferior alveolar nerve and the maxillary sinus, as well as identifying cysts or tumors.

Management of Third Molar Problems

The management of third molar problems varies depending on the specific issue and the individual's overall health. Options include observation, extraction, and other treatments:

• Observation: If the third molars are asymptomatic and do not pose a threat to adjacent teeth or structures, the dentist may recommend observation. Regular monitoring with clinical exams and radiographs is necessary to detect any changes.

• Extraction: Extraction involves the surgical removal of the third molar. It is the most common treatment for impacted or problematic third molars. Extractions can be simple or complex, depending on the position of the tooth and the surrounding structures.

  • Simple Extraction: This is when the tooth has fully erupted and can be easily removed with forceps.
  • Surgical Extraction: This is when the tooth is impacted or has curved roots, requiring an incision in the gum tissue and removal of bone to access the tooth. The tooth may be sectioned into smaller pieces to facilitate removal.

• Coronectomy: This is a surgical procedure where the crown of the third molar is removed, leaving the roots in place. It is considered as an alternative to complete extraction when there is a high risk of nerve damage. Over time, the roots may move further away from the nerve, reducing the risk of complications.

• Treatment of Pericoronitis: Pericoronitis is treated with antibiotics to control the infection, pain relievers to reduce discomfort, and irrigation to clean the area under the operculum. In some cases, the operculum may be surgically removed to improve drainage and prevent recurrent infections.

• Orthodontic Treatment: If crowding is the main issue, orthodontic treatment may be necessary to align the teeth. In some cases, the third molars may need to be extracted to create space for the other teeth.

The Surgical Procedure of Third Molar Extraction

The third molar extraction procedure typically involves the following steps:

1. Anesthesia: Local anesthesia is administered to numb the area around the tooth. In some cases, intravenous (IV) sedation or general anesthesia may be used to provide additional relaxation or to manage anxiety.

2. Incision: An incision is made in the gum tissue to expose the tooth and underlying bone.

3. Bone Removal: If the tooth is impacted, bone may need to be removed to access the tooth.

4. Tooth Sectioning: The tooth may be divided into smaller sections to facilitate removal.

5. Tooth Removal: The tooth or tooth sections are carefully removed using dental instruments.

6. Wound Cleaning: The extraction site is cleaned and any debris is removed.

7. Suturing: The gum tissue is stitched back together to promote healing.

8. Gauze Placement: Gauze is placed over the extraction site to control bleeding.

Post-operative Care After Third Molar Extraction

Proper post-operative care is essential for promoting healing and preventing complications. Guidelines include:

• Pain Management: Pain medication, such as ibuprofen or acetaminophen, is prescribed to manage discomfort. In some cases, a stronger pain medication may be necessary.

• Controlling Bleeding: Applying pressure to the extraction site with gauze for 30-60 minutes can help control bleeding. Avoid spitting or rinsing vigorously, as this can dislodge the blood clot and cause dry socket.

• Managing Swelling: Applying ice packs to the face for 20 minutes on and 20 minutes off can help reduce swelling. Elevating the head while sleeping can also help minimize swelling.

• Oral Hygiene: Gently rinse the mouth with warm salt water after meals to keep the extraction site clean. Avoid brushing directly over the extraction site for the first few days.

• Diet: Eat soft foods that are easy to chew, such as soup, yogurt, and mashed potatoes. Avoid hard, crunchy, or sticky foods that can irritate the extraction site.

• Avoid Smoking and Alcohol: Smoking and alcohol can interfere with healing and increase the risk of complications.

• Follow-Up Appointment: A follow-up appointment is scheduled to monitor healing and remove any sutures.

Potential Complications of Third Molar Extraction

While third molar extraction is generally safe, potential complications can occur. These include:

• Dry Socket (Alveolar Osteitis): This occurs when the blood clot in the extraction site is dislodged, exposing the underlying bone. It can cause severe pain, bad breath, and a foul taste in the mouth. Treatment involves cleaning the extraction site and placing a medicated dressing to promote healing.

• Infection: Infection can occur if bacteria enter the extraction site. Symptoms include pain, swelling, redness, and pus. Treatment involves antibiotics and drainage of the infection.

• Nerve Damage: The inferior alveolar nerve and the lingual nerve are located near the lower third molars. Damage to these nerves can cause numbness, tingling, or pain in the lip, chin, tongue, or cheek. In most cases, nerve damage is temporary, but it can be permanent in rare cases.

• Bleeding: Excessive bleeding can occur after extraction. Applying pressure to the extraction site with gauze can usually control bleeding.

• Damage to Adjacent Teeth: Adjacent teeth can be damaged during the extraction procedure.

• Sinus Communication: In the upper jaw, extraction of a third molar can create a communication between the mouth and the maxillary sinus. This usually resolves on its own, but in some cases, surgical repair may be necessary.

Prevention of Third Molar Problems

While it is not always possible to prevent third molar problems, certain measures can be taken to reduce the risk:

• Early Evaluation: Regular dental check-ups and radiographs can help detect third molar problems early. Early intervention can often prevent more serious complications.

• Orthodontic Treatment: Orthodontic treatment can sometimes create space for the third molars to erupt properly.

• Prophylactic Extraction: In some cases, the dentist may recommend extracting the third molars before they cause problems. This is particularly common in individuals with small jaws or a history of third molar complications.

The Evolutionary Perspective of Third Molars

From an evolutionary perspective, third molars were likely more useful to our ancestors who had a coarser diet that required more chewing power. As human diets have changed and become more processed, the need for third molars has diminished. Additionally, the size of the human jaw has decreased over time, leaving less room for the third molars to erupt properly.

Third Molars and Orthodontics

The relationship between third molars and orthodontic treatment is complex and debated. Some orthodontists believe that third molars can cause crowding and relapse after orthodontic treatment, while others believe that they have little to no effect. Current evidence suggests that third molars may contribute to late lower incisor crowding, but the effect is usually minimal.

Societal and Cultural Views on Third Molar Extraction

In some cultures, third molar extraction is a routine procedure, while in others, it is only recommended when there are specific problems. The decision to extract third molars is often based on a combination of factors, including the individual's dental health, the potential for future problems, and the cost of treatment.

Emerging Research on Third Molars

Research on third molars is ongoing, with studies focusing on various aspects such as the genetic factors that influence their development, the role of inflammation in third molar pathology, and the effectiveness of different treatment approaches. As research advances, our understanding of third molars will continue to evolve, leading to more effective and personalized treatment strategies.

Conclusion

The third molar, or wisdom tooth, is a unique tooth with its own set of challenges and considerations. While some individuals may never experience problems with their third molars, others may require intervention to prevent or treat complications. Understanding the anatomy, development, potential problems, and management options associated with third molars is essential for making informed decisions about their care. Regular dental check-ups and consultation with a qualified dental professional are key to ensuring optimal oral health.