Evaluation of technical quality of endodontic treatment – reliability of intraoral radiographs

The purpose of this study was to evaluate: 1) the use of the conventional buccolingual radiographic projection for estimating the technical quality of endodontic treatment and 2) the effect of the surrounding tissues on these evaluations. The material consisted of three radiographs of each of 108 extracted roots: a clinical radiograph, an in vitro radiograph taken in the buccolingual projection, and an in vitro radiograph taken in the mesiodistal projection. The radiographs were analysed by two observers and consensus was reached and used in the analyses. The agreement between the two observers was good, but statistically significant differences were found between recordings of the seal in the clinical radiographs and the in vitro radiographs taken in the buccolingual projection. The length of the root filling in each of the three projections was interpreted to be the same, while both inadequate seal and visible lumen apical to the root filling were recorded less frequently in the clinical radiographs than in either of the two in vitro projections. This difference was most pronounced in molar teeth. It was concluded that the lengths of root fillings could be measured correctly in clinical radiographs. Due to the anatomy of root canals in incisors and canines, there was a risk of misinterpreting an inadequate seal as adequate in these teeth. The large amount of tissue surrounding molar teeth tended to cause an underregistration of both inadequate seal and lumen apical to the root fillings in these regions.