Comparative evaluation of three methods to measure working length - Manual tactile sensation, digital radiograph, and multidetector computed tomography: An in vitro study.

AIM: Compare the measurement of working length with three different methods manual tactile sensation, digital radiography and Mutidetector computed tomography(MDCT).

MATERIALS AND METHOD: 40 human premolar extracted for orthodontic purpose were selected. Teeth were store in sodium chloride (0.9%) during the study. Access cavity was prepared and canal patency was seen with no 10 file in each tooth. Manually no 15 K file was inserted from access cavity until the tip was visible at the foramen, a silicon stopper was adjusted to the corresponding buccal cusp tip and the root canal length was measured. After that in each tooth with no-15 K file inserted from access cavity with stop at tip of buccal cusp until tip appear at foramen and x-ray was taken with digital radiograph (RVG,Satelac) and canal length was measured. After that all teeth are mounted in wax block,MDCT scan was done and in the scan images of teeth, root canal length is measured from buccal cusp tip to root end. After taking measurement of working length with all three methods and the data was stastically analyzed with One Way Analysis of variance (ANOVA) followed by Turkey's Test.

RESULTS: ANOVA and turkeys test showed that there was no significant difference in the measurements by the three procedures (p>0.05).

CONCLUSION: Working length measurement with MDCT scan and other two conventional methods does not show significant difference in measurement. Use of newer 3D imaging technique is useful in root canal treatment for measuring working length.