Facial expression drawings and the full cup test: valid tools for the measurement of swelling after dental surgery

Assessment of postoperative swelling is subjective and depends on the patient's opinion. The aim of this study was to evaluate the validity of facial expression drawings and the full cup test and to compare their performance with that of other scales in measuring postoperative swelling. Fifty patients who had one of several procedures were included. All patients were asked to fill in a form for six days postoperatively (including the day of operation) that contained four scales to rate the amount of swelling: facial expression drawings, the full cup test, the visual analogue scale (VAS), and the verbal rating scale (VRS). Seven patients did not know how to use some of the scales. However, all patients successfully used the facial expression drawings. There was a significant difference between the scale that patients found easiest to use and the others (p< 0.008). Fourteen patients selected facial expression drawings and five the VRS. The results showed that the correlations between the scales were good (p < 0.01). Facial expression drawings and the full cup test are valid tools and could be used to assess postoperative swelling interchangeably with other scales for rating swelling, and some patients found facial expression drawings were the easiest to use.