Aim: The aim of study was radiographic assessment of the effect of conservative access cavity preparation and different root canal tapers preparation on apical transportation of curved root canals.
Materials and methods: 45-extracted mandibular permanent molar having mesial root canal curvature range selected. Teeth were selected and divided into three groups, according to access cavity preparation design into: Group1 (Traditional access cavity), Group2 (Conservative access cavity), Group3 (Truss access cavity). Pre instrumentation standardized periapical x-ray were done with #15 k-file inserted inside mesiobuccal canal . access preparation done all teeth were instrumented using OneShape, Protaper Next and Trunatomy small and Prime. Post instrumentation standardized radiograph were taken master apical file inserted inside mesiobuccal canal. Superimposition of pre and post instrumentation radiographs were done using Adobe Photoshop program . Image-J software was used to measure angle of deviation between the 2 files. Statistical analysis for image analysis results was performed by applying ANOVA test (one way) followed by Tukey post hoc test.
Results:. Conservative access cavity showed highest angle of deviation when used with OneShape and Trunatomy while showed the lowest angle of deviation with ProTaper next .
OneShape showed the highest angle of deviation with conservative and truss access cavities .

- Conclusion: These findings indicated that conservative access cavity can produce comparable findings regarding apical transportation when compared to traditional and truss access cavities while using Trunatomy file system