THE USE OF MAGNETIC-RESONANCE-IMAGING TO ASSESS SWELLING AFTER THE REMOVAL OF 3RD MOLAR TEETH

Objective-To assess the suitability and accuracy of magnetic resonance imaging (MRI) in measuring the swelling of the face and lingual tissu es after removal of third molar teeth. Design-Prospective open study. Setting-Teaching hospital, Scotland. Subjects-5 patients 19-22 years o ld with bilateral mesioangular impacted wisdom teeth. Interventions-Ma gnetic resonance imaging scans taken before, and 1 and 7 days after, r emoval of bilateral lower wisdom teeth under general anaesthesia. Main outcome measures-Amount of swelling measured postoperatively compared with preoperatively. Coefficient of analytical variation calculated f or the main observer, and between him and a second observer to assess accuracy and reproducibility for each examiner and between examiners. Results-Buccal swelling on the first postoperative day was significant ly greater than preoperative (P<0.01). There was no significant differ ence in lingual swelling, The mean coefficient of variation for the fi rst examiner was 1.92 and there was no significant difference between the two examiners. Conclusions-Measurements on MRI scans are both reco rdable and reproducible for buccal swelling, but lingual swelling is m ore difficult to measure because of problems in defining the lateral b order of the tongue. MRI scans provide an objective measurement of swe lling after extraction of wisdom teeth and could be used to evaluate t he efficacy of drug regimens.