Everything you need to know about wisdom teeth

Wisdom teeth are the last molars to appear in the mouth (3rd molar). They erupt in early adulthood, hence their name wisdom tooth, wisdom molar or wisdom tooth.

They take their name from the ancient belief that, due to their late eruption, people have more wisdom teeth than when they are children, the age at which the rest of the dentition appears.

Does everyone have wisdom teeth?

Between 85-98% of young adult patients have agenesis of third molars or wisdom teeth, that is, the absence of these.

This special behavior of the third molar is due to a problem of adaptation of the masticatory apparatus to our habits, where cultural evolution plays a predominant role over biological evolution.

By this we mean that our current diet is much softer than the wild diet of primitive man, therefore, we have adapted to it and as a consequence, the space available for bone to inhabit the teeth is reduced to a greater extent than tooth size, which induces the appearance of dental crowding.

Agenesis would act as an evolutionary mechanism to this fact and would be a blind solution to this problem. They most frequently affect the most posterior tooth, the wisdom tooth being the tooth with the highest prevalence of agenesis or dental absence.

Do wisdom teeth always have to be extracted?

In the society in which we surround ourselves, it is very common for us to know a high percentage of friends, relatives and colleagues who have had their wisdom teeth extracted. This fact may lead us to think that as a general rule wisdom teeth should be extracted, but this is not always the case.

Wisdom teeth can be located in different positions, both in depth and angulation within the bone, which will help in the decision of therapeutic attitude or abstention. Thorough pre-planning is necessary to make the right decision regarding the treatment plan.

Thus, in addition to a good radiographic study, it will be necessary to evaluate different aspects such as age, symptomatology, medical and surgical history, as well as a correct anamnesis based on intraoral and extraoral exploration.

With regard to wisdom teeth that remain asymptomatic, there are no objective criteria that allow us to know the evolution they will follow, so we will maintain an expectant attitude with periodic controls, except in the following cases:

  • Patients who are going to undergo radiotherapy.
  • Third molars under removable prostheses
  • Partially erupted wisdom teeth with completed eruptive capacity (more risk of infection)
  • To reduce the risk of mandibular angle fractures (especially in young individuals who practice high-risk sports)
  • Cordals in fracture line that prevent fixation of fragments.
  • Cordae in the area of tumor resection – Cordae in the line of osteotomy necessary for orthognathic surgery
  • In cases of early loss of the 1st and 2nd molar.
  • Autotransplantation of the 3rd molar in the position of a prematurely lost 1st molar.

In cases of symptomatic wisdom teeth, the correct therapeutic attitude will be their extraction. These cases are:

  • Infections
  • Carious wisdom teeth with significant destruction
  • Wisdom teeth associated with cysts and tumors
  • Root resorption of wisdom teeth
  • Cordals that cause caries or resorption in the distal 2nd molar.
  • Atypical facial pain

What are the symptoms and complications of wisdom teeth?

The eruption of wisdom teeth occurs in outbreaks, that is, the patient refers a period of discomfort that usually lasts about a week, followed by a period of asymptomatic or mild discomfort until a new outbreak. This symptomatology is completely normal.

The wisdom tooth may either completely erupt its crown, in which case the symptoms, in general, will not be different from those discussed above regarding its normal eruption, or it may partially erupt. In this case, the wisdom tooth may be partially or completely covered with gingiva, which may present additional symptoms in addition to those of its normal eruption.

Another different case would be if the wisdom tooth is included within the bone; here a watchful waiting attitude should be taken and its evolution should be monitored with periodic radiographic controls for the possibility that it may present pathology in the future.

As previously mentioned, it is the semi-erupted wisdom teeth that are most frequently associated with the appearance of symptoms, with pericoronaritis being the first symptom to appear and the clinical manifestation most frequently associated with retention of the third molar. Pericoronaritis is an acute infectious process characterized by inflammation of the mucosal tissues surrounding the partially erupted tooth.

From a pathogenic point of view, it is easy to understand that, as the crown of the molar is partially covered, it is relatively common for food impaction to occur, which together with the existing difficulty to clean the area properly, makes pathogens such as streptococci, staphylococci and spirochetes find an ideal environment for their development, and therefore the production of pericoronaritis.

The treatment of pericoronaritis will be by means of anti-inflammatories and analgesics and, in case of suppuration, antibiotics will be necessary to “cool the acute process”. Once the acute condition has been overcome, the surgeon will decide whether to take a wait-and-see attitude or to indicate the extraction of the wisdom tooth.

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What is the ideal age to extract wisdom teeth?

There is no ideal age, although it is an important parameter. It has been demonstrated that above 25 years of age the rate of complications increases notably. However, if we compare age groups between 9 and 17 years, and between 17 and 24 years, the rate of complications is practically the same.

Do wisdom teeth move teeth when they erupt?

The debate for or against prophylactic extraction of lower third molars to prevent the appearance or increase of anteroinferior crowding has been very controversial.

The mechanism by which the eruption of the 3rd molars was attributed to the origin of the late crowding of the anterior sector would be the mesial (forward) thrust of the dentition transmitted through the interproximal contact points, in the form of a billiard ball displacement.

There are authors who argue that wisdom teeth “exert pressure from behind”, and at the same time maintain that the development of postpubertal crowding is multifactorial, that is to say, that they do not justify the generalized prophylactic extraction of these teeth since their role is not excessively important.

In the majority of the adult population, even if they have previously undergone orthodontic treatment, some degree of crowding is observed in the lower incisors.

At present, the only possible determinant role in anteroinferior crowding would be the tendency for mesial migration of the dentition. We know that it is present in the 1st molar, at ages coinciding with the eruption of the 3rd molar.

Therefore, the eruption of the lower 3rd molar can be a factor to consider in the appearance of late crowding by collaborating in the mesial migration of the dentition. However, we do not have data to defend this fact.

Therefore, we can conclude that the extraction of lower wisdom teeth to prevent anteroinferior crowding or orthodontic relapse would not be indicated.

What does wisdom tooth extraction consist of?

The extraction of a wisdom tooth is a procedure that can be performed in the dental office with a duration not exceeding 1h.

The procedure would be performed under local anesthesia. Only in very specific indications should it be performed under general anesthesia:

  • Very deep inclusions, ectopias and heterotopias (far from their usual position), where the surgical technique is different from the usual one.
  • Patients with psychic deficiencies (lack of collaboration).
  • Patients with extreme anxiety
  • Patients with polyinclusions (several retained teeth), although this would be a “relative indication”.

However, general anesthesia should be considered as a “second line” technique, due to the possible complications of the technique, and the need for the patient to be hospitalized in the clinic for at least 24 hours.

In case the patient needs more than one extraction, ideally the appointments should be separated in a period of 10-15 days, or one side can be extracted first (upper and lower homolateral), and the following week, the other two can be extracted on the contralateral side.

What is the postoperative period after wisdom teeth extraction?

The postoperative period after the extraction of wisdom teeth is very versatile. It depends on several factors such as the patient’s age, the position and inclination of the wisdom tooth, associated pathology, surgical technique, medication taken by the patient, concomitant diseases, among others. Therefore, the postoperative period will vary according to the patient and the surgical technique, knowing that pain is a totally subjective symptom.

It is completely normal for the wound to bleed slightly during the first 24 hours, and the saliva may appear stained. Some pain, swelling and difficulty in opening the mouth are also to be expected. It is not necessary to be alarmed if the face appears swollen the following day, and it can even be normal and present greater inflammation 3 days after the intervention.

The patient should warn of any circumstance that is out of the above mentioned as normal, and should contact the dentist.

In addition to all this, the following hours after the intervention, the patient should follow a series of measures:

  • Immediately after the intervention, keep biting a sterile gauze over the surgical area for 30min – 1h.
  • Apply cold to the skin at the level of the mandibular angle at short intervals (10 min) during the first 24h.
  • Do not spit or rinse during the first 24h.
  • Do not eat for 4-6h after extraction. Maintain liquid or soft diet preferably cold or at room temperature.
  • Avoid smoking and drinking alcohol the following days
  • Avoid driving immediately after surgery, as well as work or heavy physical exercise the following days.
  • Sleep with the head higher than the rest of the body (several pillows).
  • Brushing all teeth normally is possible, except in the area of the intervention during the first days. Subsequently gently brush the area.
  • The next day, rinse with water and salt or mouthwash diluted in water (Chlorhexidine 0.12%), or alternating both.
  • Maintain proper oral hygiene both pre and post-surgery (helps to minimize the risk of post-surgical complications).

The patient should also follow the medication guidelines indicated by the surgeon, usually taking an anti-inflammatory and a rescue analgesic. Post-operative antibiotics will be necessary in certain circumstances, and not as a general rule.