The impact of different viewing conditions on radiological file and working length measurement

Orafi I, Worthington HV, Qualtrough AJE, Rushton VE. The impact of different viewing conditions on radiological file and working length measurement. International Endodontic Journal, 43, 600–607, 2010. Aim To determine the effect of different viewing conditions and observer experience upon the accuracy of file and working length measurements using analogue intra‐oral radiographs. Methodology Twenty‐five observers from a range of clinical backgrounds examined working length analogue periapical radiographs of 30 extracted teeth. Each participant measured both file (FL) and working length (WL) on each of the radiographs using three different viewing conditions consisting of a viewing box, a viewing box with film masking and a viewing box with film masking and ×2 magnification. Statistical analysis was conducted to derive interobserver reliability by intraclass correlation coefficients, and multiple linear regression models were fitted to compare the mean differences between the joint consensus between specialists and estimated values for file length and working length for each of the three viewing conditions. Results Multiple regressions models were fitted and found significant differences between the use of the viewing box alone and a viewing box with masking (FL P = 0.001; WL P