Raising lingual flaps increases the risk of nerve damage

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Objective To determine whether avoiding the raising of a lingual flap reduces the incidence of lingual nerve disturbance and if this reduces the incidence of permanent nerve disturbance.

Design A randomised controlled trial in a UK dental school.

Intervention 378 patients had lower third molar removals carried out under local or general anaesthetic where a lingual flap was raised and 393 had lower third molars removed with no lingual flap. Operations were performed by several different grades of operator (from junior house office to consultant grade). There were no differences between the two groups in terms of grade of operator or type of anaesthetic. There were differences between the level of eruption, impaction and degree of difficulty between the groups — the effect of this is discussed in the text.

Outcome measures Patients' subjective assessment of altered sensation was assessed at one week. Patients reporting altered sensation were tested using light touch pinprick pain and sensation threshold, and two-point discrimination. If there was no recovery at 3–4 months surgical exploration and repair was carried out.

Results There was a significant difference in the level of paraesthesia between the two groups with 6.9% of patients in the lingual flap (control) group having paraesthesia and 0.8% in the no flap (test) group. This difference means that the absolute risk reduction in 6.1%. That is you are 6% less likely to have paraesthesia if a lingual flap is not raised.

(Odds ratios and Numbers needed to treat [NNT] calculated from data presented in paper).

Conclusions The authors concluded that the conventional UK method of lingual retraction using a Howarth's retractor is invalid and lingual retraction should be avoided.

Lingual nerve damage during lower third molar removal: a comparison of two surgical methods. Robinson P P, Smith K G. Br Dent J: 1996; 180: 456–461

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Address: P P Robinson, Department of Oral & Maxillofacial Surgery, School of Clinical Dentistry, Claremont Crescent, Sheffield S10 2TA, UK

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