Clinical Observation And Forming Ability Of Domestic M3 Nickel Titanium In Root Canal Preparation Of Posterior Teeth

Objective:To evaluate the clinical curative effect of M3 and ProTaper nickel titanium instruments file root canal preparation and shaping capabilities in rein simulated root canals.Methods:41 clinic patients with pulpities and apicitis were selected and randomly divided into two group respectively with M3(M group)and ProTaper nickel titanium root tube file(P group)preparing molar root cancal.M group have 21 teeth,64 roots,patients aged 26 to 80 years,mean age 45.67±16.58years old.P group have 20 teeth,64 roots,patients aged 14 to 76 years,mean age 42.90± 17.08 years old.Record preparation time(the preparation time including the nickel titanium root tube file into root cacanl orifice until accomplish preparation except the time irrigating and changing).A week later,record rating of pain and evaluate the incidence rate of pain.In vitor,20 resin simulated root canals were randomly divided into two groups(ME group and PE group),10 in each group.Each resin simulated root canal graduating with cutter number,marking the positioning mark.Using10#and 15#K file clear away the root canal.Then inject blue ink into the root canal,photograph by digital camera after fixation,then clean the root canal and prepare the root canal.In both groups,the electric motor was used,and the speed was set for 300 r/min respectively with M3 and ProTaper nickel titanium file.ME group were prepared to M2,PE group were prepared to F2.The red ink is injected into the dorsal root canal,and photographed with the same device and method parameters.Using Photoshop software to overlap before and after images.With the apical foramen as the center of the preparation,starting from 1mm as radius,increasing to 10mm to do the concentric circle of 10 mm and to form 20 measuring points.Using Image-Pro Plus software to measure the inner and outer surface resin removal quantum.SPSS is used for statistical analysis.Results:The experiments were no lost cases.There was no significant difference in the two groups were statistically analyzed by sex,age,teeth and other different conditons.The root canal preparation time of M group and P group was 74.28%s and 82.58%s respectively,the difference was statistically significant(P<0.05).The incidence of postoperative pain was 14.29%and 15%,there was no significant difference.In vitro,The internal side wall of the apical5,6,7,8,9,10 mm,ang the outer side wall of the apical2,3,4,5mm,PE group were removed more resin than ME group(P<0.05).The root canal deviation of the ME group was less than that of the PE group in 3,6,7,8 mm(P<0.05).The cernter ability of the ME group was better than the PE group in 3,7,8 mm(P<0.05).Conclusions:The domestic new type of M3 and ProTaper NiTi instrument have higher work efficiency in root canal preparation,domestic M3 nickel file is shorter than ProTaper.Both can effectively alleviate the pain and reduce the pain.The results of simulated root canal experiment showed that domestic M3 nickel-titanium files and ProTaper can better maintain the shape of original root canal,in apical both have better root canal formation ability,but the root canal transportation of M3 was less than ProTaper in middle canal of root,and the central ability was stronger in root canal bend.In short,the domestic M3 NiTi instruments have cost-effective price,higher work efficiency,good performance were worthy of clinical application.