The influence of viewing conditions on radiological diagnosis of periapical inflammation

Objectives To determine the effect of viewing conditions upon diagnosis of early periapical inflammatory pathosis on intra-oral radiographs, and to ex amine the effect of observer experience upon diagnostic performance in this task. Methods 50 observers examined 18 periapical radiographs using three differe nt viewing conditions (room lighting; viewing box; viewing box with x2 magn ification and masking). Their diagnoses were compared with an 'expert' diag nosis provided by repeated viewings of the films by two dental radiologists . Sensitivities and specificities were determined. Results When 'ideal' viewing conditions were used, optimal sensitivity (78% ) and specificity (78%) were obtained. Use of a viewing box was associated with significantly higher specificity than the use of room lighting (P = 0. 0016). Use of masking and x2 magnification was associated with significantl y higher sensitivity than a viewing box alone (P = 0.004). There were few s ignificant differences in diagnostic performance between observers, but qua lified dental staff had significantly higher specificities than 4th year (P = 0.01) and 5th year (P = 0.01) students when a viewing box was used alone . Conclusions This study on early periapical inflammatory pathosis gives supp ort to guidelines which recommend the use of a viewing box, x2 magnificatio n and masking for interpreting intra-oral radiographs. It also suggests tha t observer experience may influence interpretation of early periapical path osis.