This paper reports the results of a study of the reliability of a modified
version of the Index of Orthodontic Treatment Need (IOTN) for use in oral h
ealth surveys. Twelve non-specialist dental examiners were trained in the u
se of the Modified IOTN using a standardised teaching protocol lasting appr
oximately 1.5 hours. Following a school-based calibration exercise it was f
ound that nearly all the examiners achieved either good or excellent agreem
ent (mean Kappa=0.74). The average sensitivity and specificity scores were
0.90 and 0.84, respectively. The Modified IOTN appears to overcome the trai
ning and reliability problems that often accompany the use of orthodontic i
ndices by non-specialists in oral health surveys.