A Deep insight into Wisdom tooth cavity 

 Wisdom tooth cavity 

Wisdom tooth is the last tooth that erupts in the mouth. It lies behind the second molar, and is, therefore, also designated as third molar. There are four wisdom teeth in the mouth, one wisdom tooth on each side of both the jaws. Wisdom teeth are the most common missing and malformed teeth in the mouth, thus making treatment challenging if the tooth gets infected. Let’s see why does wisdom tooth cavity develops and what are the treatment options:

Why do you get a wisdom tooth cavity?

Wisdom tooth often gets infected due to incomplete plaque removal. It’s is the last tooth in the mouth and, therefore, becomes challenging to remove plaque from it, especially if erupted in the wrong position. Wisdom teeth often erupt in an abnormal position due to a lack of space in the dental arch (jaws). These conditions create difficulty in cleaning, leading to a wisdom tooth cavity.   

Partially impacted wisdom tooth is more prone to develop a cavity because the gum tissue partially covering the tooth creates a pocket for food impaction, leading to inflammation of the gums (pericoronitis) and tooth decay.

Treatment of a wisdom tooth cavity

As we all know that tooth cavities are treated either with a filling or root canal treatment, but for wisdom teeth, dentists take a slightly different approach. Let’s look at the challenges faced during wisdom tooth cavity treatment. 

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Challenges during Wisdom Tooth Cavity Treatment

The wisdom tooth is treated a bit differently than the other teeth because of the following reasons.

  • It is difficult to access, especially in people with small and limited mouth opening.
  • It has a complex and variable root anatomy.
  • Unfavorable, inappropriate angulation and position of wisdom tooth.
  • Proximity and damage to vital structures such as blood vessels and nerves. The upper wisdom tooth lies close to the sinus cavity, and the lower wisdom tooth lies next to a neurovascular (nerves and blood vessels) bundle running in the bony (mandibular) canal. 

Filling a wisdom tooth cavity

A small to moderate-sized wisdom tooth cavity can be easily filled with a composite or an amalgam filling. 

Tooth canal treatment of a wisdom tooth cavity

A root canal treatment is not usually advocated for a wisdom tooth cavity. Most dentists prefer to extract it due to its complex, and variable root anatomy and remote location. Removal of wisdom tooth does not affect the chewing efficacy in people with healthy first and second molars. However, root canal treatment of the third (wisdom) molar is considered if the health of the first and second molar is compromised.

Extraction of a wisdom tooth

Removal of wisdom tooth is anticipated if the cavity is deep or damaging the second molar (adjacent tooth). A tilted or malpositioned wisdom tooth causing periodontal problems or a cavity in the second molar is often considered for extraction. Saving the second molar is critical because it is a crucial component of our masticatory apparatus. If a second molar tooth gets hurt, it can be saved with a filling or root canal therapy because of its known root canal anatomy and a high rate of treatment success.

Risks associated with wisdom tooth surgery

Most patients experience swelling around the mouth, bleeding, limited mouth opening, and pain after the extraction for 5-7 days. According to research, 48% people develop periodontal (gum) defect at the back of the second molar.

There is also an increase incidence of infection (1-4%) and dry socket (2-26%) after wisdom tooth extractions.

Nerve injury (inferior alveolar or lingual nerve) is more likely to occur during wisdom tooth extraction. However, damage to inferior alveolar nerve is often transient and most patients recover within 6 months. Permanent damage may be seen in 1% of the patients.

If the inferior alveolar nerve lies close to wisdom tooth on an OPG, regular 2 dimensional x-ray, your dentist may request a CBCT scan, a 3D CT scan, to view proximity of the nerve more clearly. If CBCT shows close proximation of the nerve, a crown removal is considered leaving the root (coronectomy).

Read more: 10 Signs of healthy gums

FAQs (discussing the common scenarios) 

Is every tooth cavity not caused by decay? I see a hole in my wisdom tooth, yet the dentist says there’s nothing wrong with it.

No, every cavity on the tooth doesn’t indicate tooth decay. Sometimes, anatomical variations exist, and some teeth have deep fossae or indentations that look like a cavity. Wisdom teeth lie at the back of the mouth and can’t be adequately visualized in the mirror or felt with the tongue. 

Dentists are trained professionals who advise you after examining your teeth and x-rays, so if your dentist says there is no cavity, there is no need to worry about it. However, you can always go for a second opinion and discuss your concern with your healthcare provider.

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What happens if a wisdom tooth moves into the sinus cavity?

The roots of upper wisdom teeth may lie close to or within the sinus cavity. If the tooth is healthy, you don’t need to worry about its roots in the sinus cavity. If the tooth is infected and broken, the infected root can lead to sinus cavity infection. 

The displacement of the infected root of the broken-down tooth in the sinus cavity warrants immediate attention. The tooth may cause pus, infection, and pain in the sinus – a condition known as sinus perforation. You may also feel a burst of air coming from the sinus. Such cases require professional consultation with a maxillofacial surgeon.

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What is the best temporary material to fill decayed wisdom tooth cavities at home to prevent further decay and prolong extraction? Can I fill it with calcium hydroxide?

There is no temporary material at home that can be used to fill a decayed wisdom tooth. Filling a tooth first requires the removal of the dead and decayed part of the tooth. The active decay contains bacteria and requires removal and disinfection of the tooth. Sealing a tooth without removing decay can lead to pus formation and swelling in the tooth. 

I have a cavity on the front top of my upper left wisdom tooth. Can this be filled?

Yes, a small wisdom tooth cavity can be easily filled with a composite filling. Dental composite is a tooth-colored filling material that fills the tooth and lasts for atleast 5-7 years. 

I have a cavity in my wisdom tooth, but it has no pain; one dentist suggested removing the tooth, and the other dentist suggested getting it filled. What should I do?

It is difficult to advise anything without looking at the tooth and x-ray. However, lack of pain suggests a small or moderately sized cavity (dentinal caries) that can be filled with a composite or an amalgam filling. The best approach is to save the wisdom tooth as long as possible if the decay is minor and the tooth is not causing any major problem.  

However, if an x-ray reveals any future complications and an extraction at a later time, an extraction can be considered. In a such case, it’s best to discuss with the dentist all the possible treatment plans and the best approach in the long run. 

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Is it possible that a wisdom tooth is causing a cavity in the tooth right next to it?

Yes, wisdom teeth can likely cause cavities in the neighboring tooth. Often, the lack of space in the jaw allows wisdom tooth to erupt in a tilted or abnormal position that may cause difficulty in cleaning the space between the wisdom tooth and the rear (distal surface) part of the second molar, resulting in a cavity or periodontal problems in the second molar. Such a case demands removal of the wisdom tooth to save the second molar. 

Why is a wisdom tooth’s cavity filled before it is removed?

There is no reason to fill a tooth before its removal. However, it is possible that the dentist may have underestimated the spread of decay in the wisdom tooth and recommended a filling. Upon drilling and removing the decay, the extensive spread of decay may have suggested the removal of a tooth. In these circumstances, the dentist may fill the tooth and recommend its removal in the next appointment. The additional cost of a filling is often adjusted with the extraction cost, and the patient is not charged for the filling. 

I have extracted my upper wisdom tooth due to a cavity. Will my lower wisdom tooth grow and cause a problem in the future?

Yes, there are chances that the lower molar will over-erupt once the upper wisdom tooth on the same side is removed. The teeth are genetically programmed to erupt until they come in contact with the teeth in the opposite arch.

During eruption, the depression or indentation (fossa) on the molar fits into projections (cusps) on the molar in the opposite arch, interlocks the teeth, and stops their eruption. This is the mechanism of how our bite is developed. If you see your bite in the mirror, each tooth makes contact with two teeth, so when one tooth is removed, the other tooth stops its eruption. However, some drifting and movement do occur in the teeth when one tooth is removed.

Lower molars are slightly ahead of the upper, so if your lower wisdom tooth is making contact with the rear part of the upper second molar, it may stop the eruption of the lower wisdom tooth; however, if there is no contact with the upper teeth, your lower molar will likely over-erupt and require extraction. 

Supraeruption is classified into three types:

  • Mild – 0.1-1.5mm of overeruption
  • Moderate – 1.6 – 3.5mm
  • Severe – exceeding 3.5mm

Extraction or bite adjustment by trimming the chewing surface of the molar is done depending upon the degree of overeruption. Delaying extraction of the third molar with no opposing tooth can lead to masticatory inefficiency and future joint problems (temporomandibular joint dysfunction).

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How do you know if you have a cavity in your wisdom tooth? 

A black dot or hole in the tooth is a sign that you have a cavity in your tooth. Pain or sensitivity in the tooth is also a symptom of the cavity in the tooth. Bad breath from the rotting tooth can also result from a cavity. The presence of two or more signs and symptoms often indicates a cavity. However, it is always best to check with your dentist and get it sorted. 

I had two wisdom teeth pulled last weekend. Can I get cavities filled next week and then extract the other two wisdom teeth the day after? Or will I be swollen with pain?

Yes, you can get your cavities filled next week. The pain and swelling will likely settle in 7-10 days after two wisdom teeth extractions. A filling doesn’t cause any pain and swelling, so go ahead with the wisdom teeth surgeries the next day after the filling. 

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I have a cavity in my upper left wisdom teeth, and I don’t know what I should do with it. Should I remove my wisdom teeth, or should I just fill it?

Go and get it checked by the dentist. It is always best to save the wisdom tooth until it’s necessary to remove it. Small to moderate cavities are filled with a composite filling and last for years if good oral hygiene is maintained. It’s also possible to go for root canal therapy in people with uncomplicated root canal anatomy. Well, the decision to save and remove the tooth varies from person to person. 

Can wisdom teeth be removed if there is no cavity? 

Yes, it isn’t necessary to have a cavity for wisdom tooth removal. The dentist may consider removal of a wisdom tooth in the following circumstances:

  • A painful impacted wisdom tooth with frequent episodes of pericoronitis.
  • An unfavorable position of wisdom tooth.
  • The removal of wisdom tooth hurting the second molar has conflicting views among dentists. Some advocate removal of third molar and deem it an unnecessary tooth in the jaw, others propose treating periodontal problem and tooth decay of second molar more conservative and beneficial approach for the patient. In my opinion, the decision varies from case to case and is based on the position of the third molar and extent of damage caused by it.
  • For orthodontic purposes – third molar removal is considered for space creation if first molar distalization (moving it backwards) is anticipated.

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