Renton and McGurk identified risk factors associated with temporary or permanent injury to the lingual nerve caused by mandibular third molar surgery. These can help identify a patient for whom the chance of lingual nerve injury might be high. The authors are from King's College in London.

Duration of Nerve Damage

Term Used

< 6 months


>= 6 months



Risk factors associated with permanent lingual nerve injury:

(1) perforation of the lingual plate during the operation

(2) exposure of the lingual nerve on lingual flap elevation

(3) difficult procedure

(4) skill of the oral surgeon

(5) increased age of the patient



• The precise cutoff for age varies between different studies. For the implementation > 30 years of age will be used.

• The first 3 items were associated with temporary nerve injury.

• An oral surgeon who does a high number of difficult cases might be expected to have a higher rate of lingual nerve injuries.


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