Salma Mohammed Kamel, Mohammed Turky And Reham Hassan,

ABSTRACT


Aim: The Present Study Aimed To Evaluate The Influenceof The Different Sizes And Tapers Of Mechanical Preparation On Root Canal Cleanliness.

Materials and Methods: 80 Mesiobuccal Canals Mandibular Firstmolars Were Included And Mechanically Prepared To Different Apical Sizes Using K3XF NiTi Rotary Files(25, .04, 25, .06, 30, .04, 30, .06). Irrigation Procedure Was Performed After Each Instrument Change With 5.25% NaOCl, Finalirrigation Was Conducted With 17% EDTA For 1 Min. Roots Were Then Split Longitudinally And Examined Under Scanning Electron Microscopy (SEM) To Evaluate The Presence Of Smear Layer Using A Scoring System. Data Was Statistically Analysed Using Mann-Whitney U Test And Friedman?s Test, Dunn?s Test Was Used For Pair-wise Comparisons When Friedman?s Test Was Significant.The Significance Level Was Set At ? 0.05.

Results: In All Groups, There Was A Significantlymore Smear Layer In The Apical Third (P ? 0.05) Compared With The Middle And Coronal Thirds, With No Significantdifferences Between The Middle And Coronal Thirds, Except When Canals Were Prepared To Size 30 Taper .06, There Was No Significantdifference Between Smear Layer Scores At All Root Thirds. There Was No Significantdifference In Smear Layer Removal Between Different Sizes (25, 30) And Different Tapers (4%, 6%).

Conclusions: The Removal Of Smear Layer Was Less Predictable In The Apical Third Compared With The Middle And Coronal Thirds. Apical Enlargement And Increase In Preparation Taper Did Not Significantly Afect Canal Cleanliness.