The effects of developer age on diagnostic accuracy: a study using assessment of endodontic file length

Objectives: To examine the effects of developer age on image quality. Methods: Endodontic files, size 10 and 15, were placed in upper and lower m olars and premolars up to the root apex or 1.5 mm short. A series of radiog raphs were made with each of three film types: Dentus M2 (Agfa-Gevaert, Mor tsel, Belgium). Ektaspeed Plus and Ultra-speed (Kodak Eastman Co, Rochester , USA). The films were processed bi-weekly using the same Agfa chemicals (H eraeus Kulzer, Dormagen, Germany) over a 6-week period. An additional set o f Dentus M2 films was processed using Periomat chemicals (Durr Dental, Biet igheim-Bissingen, Germany). The films were viewed by eight dentists who rat ed the position of the tip of the file using a 5-point confidence scale. RO C data were analysed by means of analysis of variance. A(z) value was the d ependent variable, whereas observer age group was entered as between subjec t factor. The null hypothesis was rejected when P<0.05. Results: The diagnostic accuracies of the three films were comparable durin g the first 4 weeks. In the sixth week Ultra-speed was significantly better than the other two films (P=0.046). The Periomat chemicals showed signific antly greater consistency than the Agfa chemicals (P=0.004). Developer exha ustion significantly affected the performance of the older observers (P=0.0 08), especially when Agfa chemicals and file size 10 were used. Conclusion: Agfa chemicals older than 4 weeks significantly affect the asse ssment of endodontic file length. In earlier stages there are no significan t differences between the three films tested. Dentus M2 and Ektaspeed Plus films should be used as they require lower exposures.