Ahmed Nabil Abdel Sadek El Sebai, Alaa Diab And Geraldine M Ahmed,

ABSTRACT


Introduction: This Study Aimed To Evaluate The Effect Of 2 Different Continuous Rotation Nickel-titanium (NiTi) Rotary Systems On Apical Transportation (AT), Transportation Direction (TD), And Volumetric Change (VC) Of Severely Curved Mesio-buccal (MB) Root Canals Of Mandibular Molars Via Cone-beam Computed Tomographic (CBCT) Imaging. Methods: 60 MB Root Canals Of Mandibular Molars With A Curvature Of 25??35? Schneider?s Angle Were Assigned Randomly To 2 Groups Of 30 Canals Each According To The Instrument Used: Group A [ProTaper Next (PTN)] And Group B [ProTaper Universal (PTU)]. All Root Canals Were Shaped To An Apical Size Of 30 Using PTN Or PTU Systems: PTN X3 (#30/.07) Or PTU F3 (#30/.09?.05), Respectively. Canals Were Scanned After Instrumentation Using CBCT Scanner To Evaluate AT And TD At Cervical, Middle, And Apical Third Cross Sectional Levels, And VC For The Whole Canal.

Results: Regarding AT, There Was No Significan Difference Among The Groups (P > 0.05) In Cervical And Apical Thirds Of The MB Canal; However, In The Middle Third Of The MB Canal, PTN Showed A Significantl Lower Transportation Mean Value Than PTU (P < 0.05). PTN Showed A Significantl Lower Mean Volume Of Removed Dentin Than PTU (P < 0.05) And There Was No Statistically Significan Difference Between PTN And PTU At The Three Studied Levels (P > 0.05) Regarding TD.

Conclusions: PTN System Caused Less Canal Transportation And Preserved More Radicular Dentin Than The PTU System When Used In The Preparation Of A Severely Curved Root Canals.