Lingual nerve damage during lower third molar removal: a comparison of two surgical methods

The high incidence of lingual sensory disturbance following lower third molar removal in the UK may be due to the elevation of a lingual flap and insertion of a Howarth's periosteal elevator, in an attempt to protect the lingual nerve. We have therefore studied the validity of this technique by recording the incidence of temporary and permanent lingual nerve injury during 771 operations randomly allocated to be carried out with or without lingual flap retraction. Surgery with lingual flap retraction resulted in lingual sensory disturbance in 6.9% and this persisted, requiring lingual nerve repair, in 0.8%. Surgery without lingual flap retraction resulted in lingual sensory disturbance in 0.8% (P < 0.0001) and this persisted, requiring lingual nerve repair, in 0.3%. We conclude that avoidance of lingual retraction reduces the incidence of temporary lingual nerve disturbance and does not increase the incidence of permanent damage. This indicates that use of the Howarth's in this way is invalid, and suggests that for the majority of cases, lingual retraction should be avoided.