The Study On The Effect Of Different Patency Files In Preparing Curved Root Canals In Vivo And Vitro

Objective: This study aimed to explore the differences of 3 different root canal patency files in preparing curved root canals by measuring the endodontic interappointment pain,the amount of apically extruded debris and apical transportation.Methods: 1.60 patients with acute pulpitis on their first mandibular molars(in which curved root canal's existence have been verified by Schneider technique)were selected and divided into 3 average groups randomly.Group 1:K file,Group2:Pathfile,Group 3: M-path.Stainless steel K-files were used to prepare root canal to20 # in K-file group;and 13#?16#?19# Path File or M-Path were used in Path File or M-Path group,respectively.Then,curved root canals were instrumented by M3 rotary instruments using a crown-down technique for each group.The visual analog scale(VAS)was performed to record the patients' post-operative pain in the day they finished the operation,the first and the second day after the operation.2.Select 30 extracted mandibular one-root canal tooth,then truncate the teeth at the point of 2 millimeters above the cemento-enamel junction of the buccal boundary vertically,reserve the root of each teeth and then insert the root canal with 10# K-file until the point the file had just penetrated the apical foramina,measure the length from the stop plate to the point of the file,with one millimeter minus,thus we can get the work length.Divide these 30 tooth into 3 groups randomly,each group with 10tooth: K-file group,Pathfile and the M-path groups.Put every singly teeth into a bottle orderly,then close the rim with opaque plastic film,fill the room from the teeth to the plastic film on the top of the bottle with 3M flowable composite.Prepare the root canal by the method mentioned above.Rinse the apical foramen and the surface of the teeth root above within 2 mm of it with 1 ML distilled water.Gather the rinse solution into an Eppendorf tube.Then the solution will be centrifuged,dried by distillation.Finally we can get the weight of the amount of apically extruded debris with the help of electronic balance(mg).Scan these tooth before and after the root canal preparation,Cone-beam CT was applied here,with its included imaging analysis software,then we can analysis and measure the thickness of root canal wall—3 transverse cross section will be measured,which are 0.5mm?1mm?2mm away from the root of the teeth to the apical foramen.Then observe the apical transportation and centering ability after the curved root canal preparation.3.Do statistics analysis.SPSS17.0 software,variance analysis and SNK test were used,TA p-value less than 0.05 was considered statistically significant.Results: 1.Compared these 3 different root canal patency files in curing pulpitis,it is found that compared with K file,patients' endodontic interappointment pain degree have significantly decreased in Path File nickel-titanium group and M-Path groups(P<0.05).2.Compared with the K file group,the amount of debris extruded after the root canal preparation have significantly decreased in Path File nickel-titanium group and M-Path group after root canal preparation(P<0.05).3.When the curved root canals were prepared with 3 different root canal patency files,about the root canal deviation,when the distance between the apical foramen to the cross section is 0.5mm,compared with the Path File and M-Path groups,K file group shows significant difference(P<0.05);When the distance is 2mm,compared with M-Path group,K file group shows significant difference(P<0.05),yet compared with Path File group,K file group shows no significant difference(P>0.05).About the centering ability,when the distance between the apical foramen to the cross section is 0.5mm,compared with the Path File and M-Path groups,K file group shows significant difference(P<0.05).Conclusions: 1.PathFile root canal preparation system and M-Path system could reduce the endodontic interappointment pain,the amount of apically extruded debris,apical transportation and centering ability once the curved root canals were prepared.2.Path File and M-Path systems can improve work efficiency,preserve the root canal's anatomic form and establish the elastic bending smooth access.Thus they can be widely used in clinical root canal preparation.