Impacted third molars (''wisdom teeth')

A lower third molar sometimes fails to erupt because it faces forwards, or lies horizontally impacted against the second molar. A pocket or flap of gum (operculum) may overhang it, so that food is trapped and inflammation results. The patient, who is usually a young adult, but who may be an old one, complains of pain, which may be referred to his ear, and sometimes trismus. Secondary infection may follow.

IMPACTED THIRD MOLARS Gently syringe the space between the crown of the patient's unerupted tooth, and the flap of gum over it, with warm saline. Then insert a pledget of cotton wool soaked in oil of cloves under the flap. Give him an antibiotic, and ask him to use hot saline mouth washes. His infection may settle down.

If his infection does not settle, and you cannot refer him, you may be able to incise the gum round the edge of the apex of his tooth, so that food no longer packs around it.

If a third molar is pressing on the gum flap, and making his condition worse, refer him to have it removed, when the acute infection has subsided. If necessary, control infection and trismus with mouth washes, syringing, and antibiotics. If this fails, refer him. If you cannot refer him, give him an inferior alveolar and lingual nerve block (A 6.3).

If his second molar is carious, remove it to leave space for his third.

If his second molar is normal, and his impacted third molar is at a nearly normal angle, use bone forceps or dental forceps to nibble away his jaw behind it.

If his third molar is completely horizontal, split it with a chisel, and then extract it in two parts, with any convenient forceps.

Fig. 26-9 AN IMPACTED WISDOM TOOTH. This patient's third molar is lying obliquely in his jaw and is covered by a flap of gum. Food may be trapped and inflammation result. Kindly contributed by James Gardiner.