Accuracy, sensitivity and specificity of three imaging modalities in detection of separated intracanal instruments

Aim: To compare the accuracy, sensitivity and specificity of CBCT imaging and two dimensional periapical radiography in detection of separated intracanal endodontic instruments with and without root canal filling.

Methodology:  Eighty (n=80) extracted mandibular molars were randomly divided into four groups (n=20); control, fracture/non-filled, non-fracture/ filled, and fracture/filled.  Molars were placed in a mandible for imaging.  Conventional 2D radiography using D-speed periapical film (SKYDENT, Slovak Republic), semidirect digital radiographs using Soredex Digora Optime system (DIGORAOptime, Soredex, Finland), and cone beam computed tomography using Gendex-GXDP 800 (GENDEX GXDP-800 Kavo, Germany) were acquired.  An artifact reduction algorithm was applied.  Images were evaluated by three blinded examiners (two endodontists and one radiologist).  Qualitative examination for the presence/absence of separated instrument was performed according to a 5-point rank scale (1, definitely absent; 2, probably absent; 3, uncertainty; 4, probably present; and 5, definitely present).  Accuracy, sensitivity and specificity were calculated as well as inter-observer reliability. Statistical analysis was performed and significance level was set at 5%. 

Results: Non-filled groups showed no significant difference between all three tested imaging modalities.  Filled groups showed statistically decreased accuracy and sensitivity of CBCT.  Good inter-observer agreement was shown. 

Conclusion:  Conventional 2D radiography is a good tool for detection of intracanal separated instruments in filled canals.