Summary:
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.
Materials/Methods:
•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
Highlights:
-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.
Conclusion:
TEC seems to lead to a better preservation of the original canal anatomy during shaping compared with CEC, particularly at the apical level


