Evaluation Of The Gutta-percha Cones’ Adaptability On Curved Root Canals Prepared By Rotatory Nickel-titanium Instruments

We found that in the actual clinical operation, most of the root canalsare curved. With the increase of root curved degree, root canalpreparation difficulty increases, the instrument separation, the lateral wallperforation, the steps, increases the possibility of a change in the originalroot canal morphology, also increased the difficulty of root canal filling.A third of the root apical is the key to the success of root canal therapy.Reflect the size of the root canal micro leakage sealing ability of rootcanal filling material for root canal. In the apex of the root canal deviationrate increases, thus may increase after root canal filling of root tip KongWei leakage. Therefore, curved root canal preparation and filling hasbeen one of the difficult points of clinical operation. Due to the curvedroot canal preparation after the formation of the three-dimensionalstructure is more complex than tap root tube, the root canal fillingmaterial root of curved root canal wall can not fully fit, this study aims tofind the best prepared number and taper, makes the teeth pointed root ofcurved root canal wall adaptive optimal, provide guiding significance forclinical treatment.Objective To evaluate the Gutta-Percha Cones’adaptability to curvedroot canals prepared by rotatory Nickel-titanium(Niti)instruments, and investigate the best effect of the adaptability of Gutta-Percha Cones tocurved root canals’ wall.Methods The plastic curved root canal models were randomlydivided into8groups.Four groups were named MTwo group,and theother groups were nanmd Sendoline group.They were respectivelyprepared to0.06/20#、0.06/25#、0.04/35#、0.04/40#and.004/20#、0.04/25#、0.04/30#、0.06/30#. All these models were filled using thesingle-cone technique. After a week, the models were cutted from theapical foramen to1,2,3,4and5mm perpendicularly to the model withlow speed diamond saw. Photographs were taken useing microscope.Thefilling rates and the widths of the paste were measured by drawingsoftware.Results The Gutta-Percha Cones’filling rates were minimal at1mmsection from the apical hole.The closer it reached the root canal orifice,the greater filling rates were seen.The filling rates of various groups atapical section were maximumt at5mm section from the apical hole.Thefilling rates decreased and the widths of the paste increased with theincrease of number.When the root canals were prepared to30#or smaller,the filling rates and the widths of the paste had no significant differences(P>0.05); When the root canals were prepared to30#or bigger,the filiingrates of0.04/35#group and0.04/40#group at apical section decreasedcompared with0.04/30#group(P<0.05);There were significant differences at1and4mm sections and there were no significant differences at2,3and5mm sections of0.04/40#group compared with0.04/35#group(P>0.05).The width of the paste at apical section of0.04/35#groupincreased compared with0.04/30#group and there ware no significantdifferences at1,2,and3mm sections(P>0.05)and there were significantdifferences at4and5mm sections(P<0.05)between0.04/30#group and0.04/35#group.The width of the paste at apical section of0.04/40#groupincreased compared with0.04/30#group and there was no significantdifference at3mm section(P>0.05)and there were significant differencesat1,2,4and5mm sections(P<0.05)between0.04/30#group and0.04/40#group.The width of the paste at apical section of0.04/40#group increasedcompared with0.04/35#group and there was significant difference at1mm section(P<0.05)and there were no significant differences at2,3,4and5mm sections(P>0.05)between0.04/35#group and0.04/40#group.Compared with the groups with same number of0.06taper,the0.04tapered groups had bigger filling rates and smaller widths of the paste,butthere were no significant differences between them(P>0.05).Conclusion When the root canals are prepared to30#or smaller,theGutta-Percha Cones’ adaptability to curved root canals is best,and thefilling effect is best.