The Influence of Canal Taper on the Efficacy of Activated EDTA on the Smear Layer Removal from the Mesial Molar Canals (An In vitro study)
Objectives: The aim of this study is to investigate the effect of canal taper on the efficacy of the sonically activated EDTA to remove the smear layer from the mesial canals of molar teeth.
Material and method: 32 freshly extracted maxillary and mandibular molar teeth are collected, mesio-buccal canals with curvature less than 33% are selected. The samples then will be divided into two groups according to the taper of the preparation taper (n=16).
Group (A): Were prepared with Size 25/.06 of OC, 2Shape (TS2), then subdivided into two subgroups (n=8), based on the final irrigation protocol as following: (A1 with EDTA), (A2 with EDTA and sonic activation.
Group (B): Were prepared with Size 25/.04 of OC, 2Shape (TS1), then subdivided into two subgroups (n=8), based on the final irrigation protocol as following: (B1 with EDTA), (B2 with EDTA and sonic activation.
Standardized canal preparation for all the samples was done as following: 16 canals (Group A) were enlarged to an apical size 25/.06 of OC, 2Shape (TS2), and the other 16 canals (Group B) were enlarged to an apical size of 25/.04 of OC, 2Shape (TS1), instruments were driven with low-speed rotary hand piece at 350 rpm, and 2 Ncm controlled-torque. Then 1.5 ml of 17% EDTA will be used as a final irrigation solution without any type of agitation for both of groups A1 and B1, 1.5 ml of 17% EDTA with sonic activation for 1 minute using Endo Activator (Dentsply, Maillefer, Switzerland). Then all samples were longitudinally cut, and the residual smear layer were examined under scanning electron microscope SEM (Te scan, Vega III, Czech Republic), then the images analyzed according to the scale that was defined by Hulsmann.
Results: The descriptive statistics of the study showed that the mean of smear layer removal in Group A1and Group A2 were (1.37), (1.33) respectively, and in Group B1 and Group B2 were (1.45), (1.08) respectively. Mann-Whitney U test was performed to investigate any significant difference among the main groups; the level of significance is 0.05. The test demonstrated no significant difference between group A and B at all the thirds for both tested subgroups.
Conclusion: There was no influence of file taper on its cleaning efficiency when all the other factors are controlled.