The use of a visual analogue scale in observer assessment of postoperative swelling subsequent to third-molar surgery

Postoperative swelling after mandibular third-molar surgery was evaluated in 40 patients. Three-dimensional metric measurement of swelling was compared with observer assessment of swelling from clinical examination, from pairs of en-face photographs, and from patient self-assessment, all using a 50-mm visual analogue scale (VAS) for registration. The photographs were evaluated by two groups of observers: general practitioners (n = 5) and oral surgeons (n = 5). The following conclusions were drawn: observer assessment of swelling from clinical examination and from judgement of photographs underestimates large swelling and slightly overestimates small or no swelling compared with objectively measured swelling. General practitioners and oral surgeons assess swelling from photographs almost identically, with a slight tendency for more underestimation of large swelling by the younger oral surgeons. A 50-mm VAS seems sufficiently reliable for assessment of swelling.