Effects of CBCT acquisition protocol and additional superimposed computerized optical impressions on the accuracy of root canal length measurements: an ex vivo study.

Abstract

The purpose of this investigation was to evaluate the accuracy of root canal length determination in dependence of CBCT acquisition protocol and evaluating the influence of additional superimposed computerized optical impressions. CBCT scans with low-dose (LD) and high-definition (HD) protocols and computerized optical impressions of thirty extracted human molars were acquired. The Sicat Endo software (Sicat, Bonn, Germany) was used for CBCT root canal length (RCL) measurements with (LD+, HD+) and without (LD-, HD-) a superimposed optical impression. To evaluate the accuracy, absolute differences between test groups and the actual root canal length (ARCL) were calculated and statistically analyzed using the Wilcoxon-Rank-Sum-Test. Absolute differences between the ARCL and the tested measurement methods varied significantly (p<0.05). Both, higher resolution and additionally superimposed computerized optical impression improved measurement accuracy. Mean differences compared to the ARCL were 0.26 mm (HD+), 0.34 mm (HD-), 0.43 (LD+) and 0.66mm (LD-). 93.4% of all measurements in the HD+ group were within the limits of ±0.5 mm. Both resolution and superimposition of additional computerized optical impressions have a significant influence on root canal length measurements using CBCT.