In Vitro Study Of Preparation Efficiency Of Three Instrumentation Techniques In C-shaped Canals Of Mandibular Second Molars

ObjectiveBy scanning and measuring buccal lingual minimum wall thickness and distribution of c-shaped root canal through CBCT,guide clinical application and avoid the happening of root canal preparation accident.By comparing preparation effect that three instrumentation techniques was applied to 24 C1 and C2 type root canal of mandibular second molar,explore a kind of relatively effective preparation method in C-shaped canals of mandibular second molars.MethodsThe C1 and C2 types root canal(simple C-shaped root canal)were collected In vitro of the mandibular second molar,12 for each type.According to different classification samples using the method of block random divided into Pro Taper Niti rotary root canal file with NSK cyclotron hand piece carrier 02 taper with stainless steel K file preparation group,Pro Taper Niti rotary root canal file associated with hand use stainless steel K file preparation group,Pro Taper Niti rotary root canal file reserve team.In each group of each type 4.before root canal preparation,by CBCT scanning and three-dimensional reconstruction,measure buccal tongue lateral root the smallest thickness of tube wall of c-shaped root canal from root tip 2 mm,5 mm,8 mm video,Data were analyzed using ANOVA.Records the location of buccal tongue lateral root the smallest thickness of tube wall from root tip 2 mm,5 mm,8 mm video,Data were analyzed using c2 test.After root canal preparation by CBCT scanning and three-dimensional reconstruction,overlap thesame cross section image of before and after preparation,evaluate percentage of uninstrumented area of each instrument after root canal preparation.The data was processed with SPSS 20.0 software package.Results1.The tongue root canal minimum wall thickness is less than the buccal root canal minimum wall thickness(P < 0.05)for 24 mandibular second molar;The buccal and tongue root canal minimum wall thickness in the coronal third of the canals and the middle third of the canals more likely located at center region.The buccal and tongue root canal minimum wall thickness in apical apart more likely located at medial and distal.2.Three methods to prepare insolated simple C-shaped root canal exist uninstrumented area.The percentage of uninstrumented area for Pro Taper Niti rotary root canal file with NSK cyclotron hand piece carrier 02 taper stainless steel K file joint reserve team separately in the the coronal third of the canals [percentage of uninstrumented area(6.60 + 4.23)%] and root in the middle third of the canals [percentage of uninstrumented area(13.87 + 2.61)%] are smaller;The percentage of uninstrumented area for Pro Taper niti rotary root canal file associated with hand use stainless steel K file preparation group in central root [percentage of uninstrumented area(13.91 + 1.92)%] and apex [percentage of uninstrumented area(13.43 + 2.06)%] is lesser.Conclusions1.The lingual wall of C-shaped root canal in mandibular second molars was the thinnest zone,and care should be taken during root canal instrumentation and post space preparation to avoid perforation.2.Mechanical preparation way for C1 and C2 type root canal of mandibular second molars uses Pro Taper nickel-titanium rotary root canal file to prepare the main canals,and NSK cyclotron hand piece carrier 02 taper with stainless steel K file prepare the coronal third of the canals of isthmuses using the direction of the horizontal motion,hand withstainless steel K file lift type prepare the middle third of the canals and apex along the direction of the root canal.