Purpose: Evaluate the influence of contracted endodontic cavities (CECs) on the preservation of the original root canal
anatomy after shaping with nickel-titanium reciprocating instruments.
•n: 30 freshly extracted mandibular first permanent molar with fully formed apices
Inclusion & Exclusion: were stated
CEC group were accessed while preserving pericervical dentin and part of the chamber roof.
Traditional endodontic cavity (TECs) group were drilled following conventional guidelines; wave one gold rotary files were used for both groups.(Fig. 1).
-Micro CT scan was used to assess the inclusion criteria and root canal section and volume was asssesed using CTAn soft ware; surface areas were calculated from the exposed vertical surfaces by pixel differences between adjacent cross sections
-There were no significant difference in the mean curvature of the MB canal between the two groups as well as the volume and surface area of the canal -Straight file access was significantly different between the groups; TEC had less curvature Fig.2.
-The mean pecking motion was significantly less in TEC as well as canal transportation
-The TEC group showed significantly reduced cross-sectional areas at 1 mm from the WL compared with the CEC group due to canal obstruction that lead the file to over instrument to the side opposite to the obstruction Table 1, Fig.3.
TEC seems to lead to a better preservation of the original canal anatomy during shaping compared with CEC, particularly at the apical level