Radiographic assessment of the effect of conservative access cavity preparation and different root canal tapers preparation on apical transportation of curved root canals : (in vitro study) /

Abstract

The aim of this study was to test the effectiveness of three different access cavity designs (Traditional, conservative and Truss access cavity ) on apical transportation using three different file system (OneShape, ProTaper Next and Trunatomy) which were root canal filling removal and their effect on bond strength. Forty-five mandibular premolars were selected, checked radiographically for mesio buccal canal curvature determination using CBCT. Then canal curvature is measured using Schneider method . The forty-five were divided into three groups according to the access cavity design. Then each group is divided into three subgroups according to the file used during canal shaping. For access standardization access were done under magnification 16X using operating microscope. Teeth were mounted in silicone replicating material. Patency was obtained for root canals. Pre-instrumentation standardized periapical radiograph was obtained for teeth with #15 k-file inserted inside the mesiobuccal canal . Standardization was done by parallel technique using RinnXCP .Cleaning and shaping were done with OneShape 25/0.6 , Protaper Next till X2 and Trunatomy Small file. Root canals length was predetermined using software tool for the digital x-ray image as all roots were scanned by CBCT; 1mm was subtracted away from the apex. Post-instrumentation radiograph was taken with master apical file (OneShape 25/0.6 , ProTaper Next X2 , Trunatomy Small file). The pre and post instrumentation radiograph was superimposed then the apical transportation was assessed by difference between file K-15 file inside the canal and the final NiTi file after instrumentation .The digital radiographs were saved in JPG format and imported into Adobe Photoshop CS5 software (Adobe Systems Inc.). The digitized images were contrast filtered using Adobe Photoshop software (Adobe Systems Incorporated, San Jose, CA, USA). Using Image J software used to measure the distance between the central axes of the 15 K-file and the master apical file. Then angle of deviation between #15K-file and aster apical file was determined by drawing 3 points and two line on the files the angle formed between the intersecting lines determine the amount of deviation. Results showed that conservative access cavity showed highest angle of deviation while using OneShape and Trunatomy and distance between files at 0 mm while using OneShape. Also results showed that Trunatomy File system when compared with PTN and OneShape file systems, no siginifcant difference was shown in apical deviation. The result was in accordance with Elkhodary et al . that Trunatomy file system was able to effectively shape curved root canals in terms of canal transportation and centering ability when compared to PTN and M-pro Regarding the conservative access cavity this could have been due to the coronal interference and absence of straight line access to the canal. While the difference between files may be due to the difference in metallurgy properties of each file system.