The thought of wisdom tooth removal might be relieving for some, yet many people with impacted wisdom teeth get scared by it. It is probably due to the myths attached to the procedure of its removal and its rare complications that have been propagated as common, like permanent nerve damage.
The word “permanent nerve damage” itself is worrisome, but it is one of the rarest complications of wisdom tooth removal.
This article is a thorough account of risks, complications, vulnerability, and management of the nerve damage that might occur due to the impaction or removal of wisdom teeth.
Medical Classification Of Nerve Injuries
Nerve injuries have three main types:
- Neuropraxia.
- Axonotmesis.
- Neurotmesis.
Neuropraxia
This type of nerve injury is the commonest and results from pressure or blunt trauma. Neuropraxia can recover spontaneously in a short period.
Axonotmesis
This type of nerve injury occurs due to a crushing injury. 6-12 months are required to recover from it. It might lead to permanent nerve damage down to the severity of insult to the nerve.
Neurotmesis
This type is the full nerve dissection that requires micro-surgically repair for recovery.
Why Is Permanent Nerve Damage Caused In The Oral Cavity?
The nerve might get stretched, irritated, bruised, or squeezed due to the following reasons:
Nerve Impaction By Wisdom Tooth
An impacted third molar, called the wisdom tooth, might compress the nerve. If the wisdom tooth is located upon the mandibular canal or inside it, its eruption and growth will damage the inferior alveolar nerve, causing paresthesia in the oral cavity. It, however, happens in rare circumstances.
Nerve Damage Due To Wisdom Tooth Removal
In rare events, nerve damage is caused by wisdom tooth removal.
The following situations make the nerve more prone to being damaged during wisdom tooth extraction:
- When the root of the tooth being extracted is located adjacent to the nerve.
- When the multiple roots of the wisdom tooth are curved around the mandibular canal, it complicates its extraction further.
- When the patient is non-cooperative and plays havoc in the middle of the procedure.
Other Reasons For Permanent Nerve Damage
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Mandibular Fracture
If there is a fracture to the mandible, commonly known as the jaw bone, it will also damage the mandibular canal. The nerve most prone to damage is the inferior alveolar nerve; it might be dissected due to the mandibular fracture and result in permanent nerve damage. Mandibular fractures can occur due to a road traffic accident or injury in sports such as boxing.
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Dental Cysts
Dental cysts such as follicular or dentigerous cysts are a type of odontogenic cysts and developmental cysts of the jaws.
These are usually associated with the eruption of wisdom teeth, are not symptomatic, and are usually diagnosed accidentally on X-rays. They can increase in size to the extent that they expand the bone and cause its fracture. As a result, dental cysts can cause permanent damage to the inferior alveolar nerve causing dental paresthesias.
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Traumatic Tooth Damage
Damage to the premolars, whose roots are located near the inferior alveolar nerve, can cause damage to the nerve, which might be permanent if severe.
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Tumors
Malignant schwannoma is a tumor of the peripheral nerve sheath of the inferior alveolar nerve, which might damage it permanently. Other oral or bone tumors in the oral cavity near the mandibular canal can also lead to permanent nerve damage.
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Bone Infections Of The Mandible, Like Osteomyelitis And Osteonecrosis, Due To Bisphosphonates
Osteomyelitis of the mandible leads to fracture and nerve damage to the inferior alveolar nerve. Moreover, bisphosphonates cause osteonecrosis of the mandible, which also affects the inferior alveolar nerve function.
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Nerve Damage During Implant Placement
Inferior alveolar nerve injury during implant placement can be due to retraction of mental nerve, mechanical injury with the drill or the implant itself, or thermal injury.
Pre-op and post-op imaging and its evaluation are recommended to prevent such complications. The implant should be removed if post-op digital imaging indicates impingement of the inferior alveolar nerve.
The Extent Of Nerve Damage During Tooth Impaction Or Extraction
The nerve most vulnerable to damage due to wisdom tooth extraction and impaction is called the trigeminal nerve. To be more specific, it is the inferior alveolar nerve which is a branch of the mandibular nerve (the third branch of the trigeminal nerve being damaged in wisdom tooth removal). This is less common among all the complications of wisdom tooth extraction, with dry sockets at the top of the list. Injury to the trigeminal nerve might be major or minor depending upon the extent of its damage.
Symptoms Of Inferior Alveolar Nerve Damage
This branch of the trigeminal nerve is concerned with the sensation of the chin, gums, lower lip, and tongue. So if the inferior alveolar nerve gets hit during tooth extraction, it would result in paresthesia, a prickling or tingling feeling, and numbness in the innervating regions. This nerve injury would not affect any motor functions of the patient’s mouth, tongue, or jaw. It might hinder daily activities like drinking and eating due to loss of sensation; however, it shouldn’t be worrisome concerning motor activities.
Minor Nerve Injury
Slight damage to the nerve during tooth extraction, particularly the wisdom tooth, will not require any treatment most of the time. It might take several days or weeks for the symptoms to be relieved without surgical or medical intervention.
Symptomatic treatment may be done for temporary relief; for instance, over-the-counter medications like paracetamol or ibuprofen should be taken to relieve pain and inflammation.
Major Or Permanent Nerve injury
If the symptoms of nerve damage do not relieve on their own, even after several weeks or months, surgical intervention might be considered for treatment. However, if the nerve damage is permanent, the patient might not feel the same way again, and the symptoms may last for a lifetime.
The extent of nerve damage would determine the possibility of success of the surgical treatment. The nerve can be repaired surgically if the injury is not too deep.
Dentists are always concerned about nerve injury during interventions such as wisdom tooth extraction or other orthodontic procedures. However, if the patient feels like the dentist has been negligent during the removal of his wisdom tooth, they might ask for compensation from the clinic. Compensation can be claimed in cases where patients were not informed of the risks of the procedure beforehand.
The Risk Of Nerve Damage During Wisdom Tooth Extraction
Before any such surgery, the dentist takes the patient’s consent, explains the procedure, and informs them about all the possible complications and risks.
There is nothing to be alarmed about because most tooth extractions are done without complications.
It is, however, necessary to inform the patient regarding the pros and cons of the procedure and leave it to the patient to agree or disagree with it.
This way, the patient can be mentally prepared for any potential risks the procedure carries. If permanent nerve damage occurs, then it is not always negligence on the dentist’s part. It might be done by accident during the procedure as, after all, it is done by a human hand. The dentist, however, might land in trouble if they had kept the patient oblivious to the potential risks and complications of the extraction process.
Permanent Nerve Damage, Rare Or Common?
You might have never come across people with sensations in their lower lip, chin, teeth, and gums, right? However, you may surely have met many people who have got their wisdom teeth extracted. This might vaguely explain the rarity of nerve damage after wisdom tooth extraction.
Medically, it is a very rare event that someone’s inferior alveolar nerve gets damaged permanently, but this complication does exist. It is, therefore, important to discuss it with the patient before the procedure because you never know whose nerve gets hit.
Anatomy Of The Wisdom Tooth And Inferior Alveolar Nerve
To help understand permanent nerve damage, we need to know the structure and location of our wisdom tooth and its relation to the inferior alveolar nerve.
Wisdom Teeth
Wisdom teeth, also known as third molars, are the last set of teeth to grow in adults behind the second molar teeth. These might be labeled as vestigial parts of the body as they do not have any major function. However, according to historians, our ancestors needed them, as back then, there were no proper cooking, grinding, and blending methods. So they needed wisdom teeth to make the food digestible, mostly hard nuts, undercooked meat, and raw plants.
According to statistics, 53% of us have wisdom teeth, while the remaining might or might not have them.
The eruption of wisdom teeth occurs from 17 to 25 years of life. These teeth might be impacted in the jawbone or gums in many people and make the eruption extremely difficult and painful. The affected individual might also experience severe inflammation, tenderness, swelling, and pain, which hinders their daily activities and affects their eating and drinking. The wisdom teeth, thus, need to be extracted to help the individual get saved from such agony.
Inferior Alveolar Nerve
It is the branch of the mandibular division of the trigeminal nerve and is entirely sensory in function.
The lower jaw has a mandibular canal through which the inferior alveolar nerve travels anteriorly. The roots of molar teeth lie above the mandibular canal and whatever runs through it. If the roots of these molar teeth curve around the mandibular canal, the extraction becomes extremely difficult.
The inferior alveolar nerve supplies branches to the second premolar tooth, the three molar teeth, and their relative gums.
It then divides into its two final branches, which are stated below:
Incisive Nerve:
It runs in the mandibular canal and supplies the first premolar tooth, canines and incisors, and the gums related to these teeth.
The Mental Nerve:
It comes out of the mandible through the mental foramen, a bilateral opening for the exit of the mental nerve. It supplies the lower lip and chin. It can be palpated and seen near the premolar teeth’ roots.
Lingual Nerve:
Another branch of the mandibular nerve, the lingual nerve, is also prone to damage during this procedure and causes oral paresthesia.
It is mentioned time and again here that the damage is only sensory and not the motor. It is because the part of the nerve prone to damage during dental procedures has only sensory function. However, the inferior alveolar nerve also supplies the mylohyoid muscles, which help in jaw movement and swallowing. But the mylohyoid branch is not vulnerable to damage during dental procedures.
How To Prevent Impaction And The Need For Extraction Of Wisdom Teeth?
According to a famous saying, ” a stitch in time saves nine.” We cannot fight nature and save ourselves from the agony of wisdom tooth eruption, but we can care for it so that it does not get inflamed. This way, there will be almost no chance of the most feared permanent nerve injury.
The following measures can be taken to prevent the condition from getting worse:
- Routine dental visits when the signs and symptoms of wisdom tooth eruption appear. Some of its symptoms are pain, tenderness, and swelling.
- Brushing teeth twice or thrice a day. Reach out for the hidden gems, aka wisdom teeth, and brush them properly to remove any debris that can cause infection and irritation.
- Use dental floss once a day.
- An interproximal toothbrush that can fix between teeth can be used.
- Rinsing of mouth with alcohol-free antibacterial mouthwash.
What Does The Patient Feel After Nerve Damage?
The patient cannot tell during the procedure that their nerve has been damaged. However, after the effect of the local anesthetic is gone, the patient can feel the effects of the nerve damage a few days after the procedure.
The patient feels a total or partial sensation loss in the affected area, mostly the tongue’s inner side. There would be a loss of taste and touch sensation, followed by pain, prickling, tingling, and numbing sensations in that area. Altogether these symptoms are called dental paresthesias.
The loss resulting from such damage is only sensory and does not affect jaw movement and other motor functions.
Modern Techniques To Check The Vulnerability Of Nerve Damage Before The Procedure
Digital X-ray Imaging
There have been revolutionary advancements in every walk of life in the past decade, and the field of medicine and dentistry is second to none in this regard. Modern diagnostic and therapeutic techniques have minimized the complications and risks of medical and dental procedures to a huge extent. The incidences of dental paresthesias have also been reduced owing to digital X-ray imaging.
Before any dental procedure, a full-mouth X-ray is done, and the dentist obtains the digital image, which locates all the related structures to the tooth being extracted. After thoroughly studying these X-rays, dental surgeons find it convenient to remove the wisdom tooth without complications.
The amazing part about these digital X-rays is that they can show dentists if wisdom teeth are growing in adults and whether a person will have wisdom teeth in the future. They can also inform the dentist if wisdom teeth become impacted in the patient so the dentist can remove them even before impaction.
MRI neurography
MRI neurography may be done to evaluate the lingual nerve function, which might be impaired due to a procedure. If the nerve pain present before a diagnostic nerve block is relieved after it, surgical repair can be done for nerve damage.
DESS MRI protocol is an imaging technique for the evaluation of the lingual nerve up to its terminal branches. It can therefore be performed for further evaluation.
Management Of Nerve Damage
Conservative Management
The nerve damage can be managed either with conservative management or, if that fails then, surgical repair.
Conservative management includes anti-inflammatory medication, vitamin complex supplements, and medications for neuropathic pain like pregabalin and general painkillers.
Physiotherapy of the jaw is also a part of conservative management.
Surgical Options For Nerve Repair
Surgical nerve repair depends upon imaging results and after evaluating the patient clinically before, during, and after the procedure which caused the complication.
External Neurolysis
If the nerve structure is intact but attached to the surrounding structures by scar tissue, then external neurolysis is performed. This procedure includes the removal of scar tissue. After that, the nerve is covered with a porcine nerve protector.
Neurorrhaphy
If the nerve is severely or completely damaged, then neurorrhaphy is done. It is a microsurgical procedure in which the damaged part of the nerve is removed, and the nerve stumps before and after the damaged part are attached using micro sutures. It is then covered with a porcine nerve protector.
Surgical treatment is more aggressive and involves the removal of the jawbone to expose the nerve canal and then placing a bone graft after the nerve repair. The bone graft is usually taken from the same patient as it has more success rates. If it is impossible, an allograft taken from a cadaver is used during this surgery. These surgeries are performed in the operation theater under general anesthesia or intravenous sedation. After being discharged from the hospital, it is recommended that the patient takes bed rest for one day. The patient should refrain from strenuous physical activity for one week after the surgery.
The patient might have postoperative tingling sensation and paresthesias, which will take some time to go away.
The surgical repair success rate is more in patients with numbness at 85% than in patients with both pain and numbness at 65%.
Conclusion
Wisdom tooth removal or impaction might rarely be associated with permanent nerve damage of the inferior alveolar. It can result in dental paresthesias of a lifetime. It is a rare event, and dentists are very careful during the extraction to prevent nerve damage.
Permanent nerve damage is a rare complication of wisdom tooth removal, and you don’t deserve to bear this agony for something as rare as permanent nerve damage.
It might surprise many people, but the impacted wisdom tooth can ping on the inferior alveolar nerve causing damage. So fear of nerve damage should not be an excuse for not getting rid of an impacted, inflamed and infected wisdom tooth.
Dentists can pre-evaluate the chances of nerve damage during a procedure using digital X-rays. These modern techniques reduce the risks further.