Rating the preventive indication for mandibular third-molar surgery. The appropriateness of the visual analogue scale

The aim was to determine whether a visual analogue scale (VAS) is an appropriate way for general dental practitioners and oral surgeons to rate their judgement of the indication for therapy of asymptomatic mandibular third molars. Thirty general dental practitioners and 10 oral surgeons had to judge the need for removal of 36 third molars. They were also asked to estimate the strength of the indication for extraction on a VAS. To assess the reliability of the judgment, the 36 cases were duplicated. For each participant, two mean indication indices with 95% confidence limits were calculated, one index for molars proposed to be extracted and one index for molars proposed not to be extracted. Pearson's correlation coefficient was used to estimate the intra-examiner reliability and the correlation between the number of molars proposed for extraction and the mean indication index. The correlation between the number of molars proposed to be extracted and the mean indication index was high (p < 0.001). The intra-examiner reliability was also high, with a mean correlation coefficient of 0.72 for the general practitioners and 0.84 for the oral surgeons. No single judge presented any overlap for the 95% confidence limits for the mean indication index of teeth proposed to be extracted versus teeth proposed not to be extracted. These results indicate that the VAS seems to be an appropriate method for analyzing the judgements on a therapeutic strategy like extraction versus no intervention for asymptomatic mandibular third molars.