Compare The Quality Of Apically Extruded Dentin Debris By Single File And Multi File

Objectives: In this study by measuring the time of root canal preparation and the amount of solid fragments released from the root canals during root canal preparation,we evaluate the Ni-Ti root canal preparation efficiency and launch apical quantity of debris under different exercise machine and provide reference for the selection of nickel titanium instruments for clinical use.Materials and methods: Performed 80 total or orthodontic reduction of first mandibular premolars in vitro and remove the odontolith of the tooth surface and soft tissue around crown,have routine open pulp and pulp extraction and measure the work length,and randomly divided into 4 groups(n=20).They are stainless steel K file group,ProTaper group,WaveOne group and Reciproc group which were used for root canal preparation.The detached teeth were fixed and closed in the cap of the liquid collecting bottle,and the collected crumbs were dried and weighed at the end of the preparation.Recorded the time of each nickel titanium file to prepare the root canal from entry to exit which did not include the replacement of the instrument and the time of flushing.Preparation time and amount of debris were accumulated and recorded after each tooth ready to end in the same group.Results:Detrital mass respectively are 0.0068±0.0006 ? 0.0048±0.0005 ? 0.0027±0.0004 ?0.0025±0.0007,apical release of debris of WaveOne and Reciproc are the least(P<0.01),and there was no significant difference between the two groups.Readiness time respectively are395.4±34.6?265±9.5?94.5±8.3?125±6.4,readiness time of WaveOne and Reciproc are the shortest(P<0.01),and there was no significant difference between the two groups.Conclusion: In the process of root canal preparation,the rotary nickeltitanium file is used for pushing out the minimum quality of the root tip,and the shortest time needed for the preparation of the root canal which is worth popularizing in clinic.