Reliability of radiographic observations recorded on a proforma measured using inter- and intraobserver variation: a preliminary study

Aim The aim of this preliminary study was to test the reliability of radiog raphic evaluation of features of endodontic interest using a newly devised data collection system Methodology Twelve endodontic MSc postgraduate students and one specialist endodontist examined sample radiographs derived from a random selection of 42 patients seen previously on an Endodontic New Patient Clinic (EDI). Each student examined a random selection of 8-9 roots on periapical radiographs of single- and multirooted teeth, with and without previous root canal the rapy and 3-4 dental panoramic tomograms (DPTs). A total of 100 roots were e xamined. A proforma was used to record observations on 67 radiographic feat ures using predefined criteria. Intra-observer agreement was tested by aski ng the students to re-examine the radiographs. The principle investigator a nd the specialist endodontist examined the same radiographs and devised a G old Standard using the same criteria. This was compared with the student as sessments to determine inter-observer variation. The postgraduates then att ended a revision session on the use of the form. Each student subsequently examined 8-9 different roots from the pool of radiographs. A further assess ment of inter-observer variation was made by comparing these observations w ith the Gold Standard. Results Of the 67 radiographic features, only 25 had sufficient response to allow statistical analysis. Kappa values for intra- and inter-observer var iation were estimated. These varied depending on the particular radiographi c feature being assessed. Fifteen out of 25 intra-observer recordings showe d 'good' or 'very good' Kappa agreement, but only three out of 25 interobse rver observations achieved 'good' or 'very good' values. Inter-observer var iation was improved following the revision session with 16 out of 25 observ ations achieving 'good' or 'very good' Kappa agreement. Conclusions modification to the proforma. the criteria used, and training f or radiographic assessment were considered necessary to improve the accurac y and reproducibility of the observations entered.