Wisdom tooth is referring to the third molar. It is a normal tooth if the eruption path correct, and suppose to serve the mastification (chewing) function. Unfortunately for Asian people, our lower jaw are relatively small compare to the teeth size, causing the third molar to alter it eruption pathway and further lead to due to lack of space in the posterior region for it to erupt properly. The radiography image below (picture 1) show normally erupted lower left third molar, and impacted lower right third molar.
When the lower third molar get impacted, in the early stage, the surrounding gum will always having some degree of inflammation due to plaque accumulation underneath the partially covered gum, which known as “Pericoronitis”. (Picture 2)
In this stage, tissue debridement and medicine may probably control the inflammation. Besides the soft tissue inflammation, the risk of getting tooth decay in between the impacted molars also very high. The reason is difficult in cleaning the two surface between impaction, flossing of interdental space is almost impossible.
If the partially covered gum did not recede completely, the inflammation reaction will progress and become more frequent and more severe, the whole surrounding soft tissue will become swollen, and causing pain, difficult in swallowing and chewing.
At this stage, surgical removal of impacted lower third molar (wisdom tooth) is necessary. After giving local anesthesia to numb the surgical area, the gum will carefully cut and open a flap to expose the underlying bone and the impacted tooth. (Picture 3)
The surgeon will use a surgical drill to gutta the bone around the impacted tooth. The impacted wisdom tooth was then being cut & divided into several pieces to relief the impaction. (picture 4)
After the tooth being cut into smaller pieces, the fragments was removed piece by piece (picture5).
Sometime the fragments of the separated tooth may still having difficulty to remove due to curve root or engaged under the bony undercut. In this situation, the surgeon need to do more grinding of that portion to reduce its size, to facilitate removal of all tooth fragments. (picture 6)
After the removal of wisdom tooth, the surgeon will attempt to achieve haemostatic (stop bleeding) by applying some direct pressure to help the blood to clot.
The soft tissue flap will be stitched (suture) to immobilise it and help to stabilise the blood clot. (Picture 7)
The discomfort and pain may last 2 to 3 days after surgery, but it is controllable by taking pain killer. Removal of stitches after 10-14days. Soft tissue healing usually happen within 2 weeks (Picture 8). The whole process of bone remodeling and the tooth socket filled with bone will take 2 months.
The main concern of complication of wisdom tooth surgery is the injury to the Inferior Dental Nerve (ID), a sensory nerve supply to the cheek, chin & lip. (Picture 9)
It is a standard procedure to take a radiograph of the impacted wisdom tooth to evaluate the degree of impaction, the extend of decay, the distance from ID Nerve. Then the surgeon will based on the finding to plan the surgery, how wide to open up the gum to expose the impacted wisdom tooth, the depth of surrounding bone to cut away, the safety distance to cut from ID nerve, the direction of cut & divide the wisdom tooth into pieces etc.
Injury to the ID nerve may cause numbness sensation over it coverage area (Picture 10).
Usually the numbness sensation is temporary due to compression of the ID nerve. It will recover gradually within 6-12 months. Prolonged numbness (Paralysis) due to severe nerve injury although might happened, but the chances are low if the treatment procedure are planned properly.
Other possible complications will be prolonged pain & discomfort, usually due to dense socket bone around the wisdom tooth that restrain the blood clot formation, a term known as Dry Socket (Picture 11).
post-operative swelling due to edema (a condition characterized by an excess of watery fluid collecting in the soft tissue) or hematoma (a solid swelling of clotted blood within the tissue), or sometime bruises. (Picture12)
Dr Goon Yong Por