Dr Andrew Chan Kieng Hock

Consultant Oral Surgeon Private Dental practice

Klang, Selangor.

Wisdom tooth surgery is one of the most common minor oral surgical procedures performed in the dental clinic setting by a dentist, often under local anaesthesia (LA). But some complex and challenging cases are best undertaken by a trained consultant oral surgeon or an oral and maxillofacial surgeon, to minimize post-operative side- effects. Dr Andrew Chan Kieng Hock explains the finer points of wisdom tooth surgery and how to survive it with as little discomfort as possible.

Figure 1: Panoramic radiograph showing impacted lower left wisdom tooth.

Photos by Dr Andrew Chan Kieng Hock

Figure 2: Clinical view of the partially impacted tooth.

To Remove Or To Retain?

Usually, a wisdom tooth—or better known as a third molar— erupts in the oral cavity between the ages of 18 and 25 years. However, it is not uncommon for a wisdom tooth to emerge at a later date in some people. As a matter of fact, this tooth is the last molar and the final adult tooth to erupt. Most people will feel some form of discomfort, pain, swelling, or even fever during the phase of eruption.

The accurate definition of an impacted tooth means a failure to completely erupt into a normal functional chewing position due to insufficient space (limited jaw arch); an obstruction by another tooth; an abnormal development of a tooth position (ectopic position); and sometimes, but very rarely, due to a tooth being fused (ankylosed) with the alveolar bone.

A tooth is said to be completely impacted if it is entirely covered by the gum and/or the alveolar bone in the jaw hence rendering it clinically invisible. A partially impacted tooth is clinically visible but has failed to reach the functional chewing position.

Some studies among adults show that the prevalence of one or more impacted wisdom teeth is around 25% to 73%. The reason for the huge difference is mainly due to the fact that some dentists in certain countries believe strongly in prophylactic or preventive removal of asymptomatic wisdom tooth while dentists from other countries don’t. There are obvious differences in the consensus among dental practitioners from country to country. To overcome the differences, several established dental bodies and healthcare policymakers have produced certain guidelines and best clinical practice which are regularly updated to help surgeons make a more sound and objective decision in the management of impacted wisdom tooth. One such guideline is by the UK National Institute for Health and Care Excellence (NICE).

In this article, some of the more common reasons for surgical removal of impacted wisdom tooth and its associated side- effects are discussed.

Figure 3: Panoramic radiograph showing right lower wisdom tooth associated with dentigerous cyst.

Indications To Remove A Wisdom Tooth

There are various valid reasons to remove an impacted wisdom tooth before it develops harmful side-effects. Each tooth and each individual’s circumstances are unique. Therefore, the decision to remove must be solely based on careful risk-benefit assessment.

If a tooth is at high risk of developing a disease, the decision to remove it is justifiable. On the other hand, removing a healthy tooth is unjustifiable.

The following summarizes the most common indications for removal:

• Unrestorable dental decay due to area of food and plaque stagnation between the wisdom tooth and the adjacent molar.
• Non-treatable pulpal/ periapical infection
• Infection under the gum flap of the tooth (pericoronitis). Cited as the most frequent reason for removal of impacted wisdom tooth but only after the second or subsequent episodes unless the first attack is very severe. Occasionally, the surgeon may decide to just excise the gum flap (operculectomy) using a blade or a laser to facilitate the tooth eruption. However, the risk of recurrence is always a possibility.
• Widespread inflammation of soft tissue (cellulitis); collection of pus (abscess); and bone infection (osteomyelitis), all of which are usually due to untreated pericoronitis.
• Braces (orthodontic) considerations whereby, wisdom teeth must be removed for proper retraction and alignment of the upper and lower teeth. However, there is little evidence at the moment to support the removal of wisdom teeth solely to prevent crowding of front teeth.
• Prophylactic removal due to specific and serious medical and surgical conditions such as abnormal heart valves which are prone to infective endocarditis, organ transplants, hip and joint replacement implants; chemotherapy, and radiotherapy.
• To facilitate tooth restoration including dental prosthesis. For example, an impacted wisdom tooth under an existing denture.
• Internal/external tooth resorption including the adjacent tooth.
• Tooth in the line of fracture which will hinder the management and healing process.
• Fractured wisdom tooth.
• Cyst/tumour development such as dentigerous cyst and ameloblastoma.
• Tooth hindering reconstruction jaw surgery.Tooth involved in the zone/ field of radiation or tumour resection.
• Tooth used to act as a suitable donor for intentional tooth transplantation.

If surgical intervention is not warranted, a constant periodic monitoring every 6 to 12 months by clinical or radiograph examination is essential because of the future changes in position and/or pathology. The relative risk of retaining an impacted wisdom tooth must be discussed thoroughly with all patients concerned.

In some rare  instances, the person’s occupation or circumstances may necessitate them to be away from accessing dental healthcare facility. For instance, soldiers, navy personnel, astronauts, oil and gas explorers, or even overseas students. In such instances, the decision to remove the wisdom tooth earlier than later is justifiable.

Another pertinent issue is regarding the removal of opposing or contralateral tooth. It is generally agreed that if the offending tooth is associated with the criteria, removal is warranted.

Figure 4: Surgical removal of both the upper and lower wisdom teeth.

Wisdom Tooth Surgery: What To Expect?

The surgical procedure is usually straightforward for simple cases and has a minimum potential risk and morbidity when performed by a competent surgeon using sound surgical technique. The surgeon will take appropriate medical and dental history; clinical examination, and a diagnostic radiograph before the onset of the surgery. The imaging is required to identify clearly the position of the tooth and the proximity of nearby vital structures such as the inferior alveolar nerve in relation to the wisdom tooth.

In a dental clinic setting, the procedure is most often performed under local anaesthesia or supplemented by intravenous (IV) sedation. Sometimes, it can also be performed under general anaesthesia (GA) in a hospital setting, if need be, in such cases as removal of all four wisdom teeth concurrently, or if the tooth is associated with cyst/ tumour management.

Appropriate post-operative painkillers, antibiotics, and anti-swelling medications are normally prescribed after the surgery. It is important to maintain good oral hygiene besides taking all the necessary medications throughout the healing process.

The recovery of wisdom tooth surgery, under proper care, is usually uneventful with some swelling, pain, discomfort and limitation of mouth opening. All these symptoms will resolve within a week or so. But unfavourable surgical outcomes is inevitable in some rare complex cases which include prolonged bleeding or swelling; prolonged pain, development of dry-socket (alveolar osteitis); severe lockjaw (trismus); local and/or systemic infection; osteomyelitis, violation of vital nerve structures which causes temporary or permanent numbness (paraesthesia); jaw fracture, and creation of sinus communication (oroantral fistula).

In conclusion, the verdict to remove or retain a wisdom tooth can be a daunting task to many people, and present challenges even to a practising dentist. As discussed, there are numerous factors influencing the risk and benefits in the management of wisdom tooth. Therefore, a comprehensive pre-surgical and diagnostic assessment is crucial in making the final decision after taking into consideration all the specific circumstances and the needs of each individual. A careful and competent practitioner would always keep in mind that there is no ‘one-size- fits-all’ remedy and each case should be assessed separately and carefully. HT

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