Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2016-09-05, 09:33:59 | version 1.38.0
| technique canal shaping 18 roots 3 2016 with cutting angles (CW angles) much greater than WaveOne/Reciproc movements. This results in the TF Adaptiveinstrumentisworkingforalongertimewith a CW angle, which allows better cutting efficiency and removal of debris (and less tendency to push debris apically and laterally), because the flutes are designed to remove debris in a CW rotation. ThisresultsinTFAdaptivetakingadvantageof the use of a motion that is more similar to continuous rotation for optimal debris re- moval. There are obviously some changes intheanglesdependingoncanalanatomy (themorecomplex,thesmallertheCWan- gle), but they do not seem to significantly influence the overall result. On the con- trary, these changes influence resistance tometalfatigue,sinceTFinstrumentsused with Adaptive motion were found to have superior resistance to cyclic fatigue when compared to the same TF instruments used in continuous rotation.36 As mentioned before, flexibility is a fun- damentalpropertytominimiseiatrogenic errors while negotiating canals, both in reciprocationandincontinuousrotation. The use of a reciprocating movement, therefore, does not significantly help a NiTiinstrumentofgreatertapertonegotiate curved canalswithnoiatrogenicerrors.Itmainlyhelpstore- duceinstrumentationstressandtheriskofintracanal failure.Inaddition,astudyaimedtocomparethefre- quencyofdentinalmicrocracksafterrootcanalshap- ing with two reciprocating (Reciproc and WaveOne) and one combined continuous reciprocating motion Twisted Files Adaptive (TFA) rotary system. Ninety molars were chosen and divided into three groups of 30 each. Root canal preparation was achieved by us- ing Reciproc R25, Primary WaveOne and TFA systems. All the roots were horizontally sec- tioned at 15, 9 and 3 mm from the apex. The slices were then viewed each under a micro- scope at x 25 magnification to determine the presence of cracks. The absence/presence of crackswasrecorded,andthedatawereanalysed with a Chi‑square test. The significance level was set at P < 0.05. The results found that in- strumentation with Reciproc produced sig- nificantlymorecompletecracksthanWaveOne and TFA (P = 0.032). The TFA system produced significantly less cracks then the Reciproc and WaveOnesystemsapically(P=0.004).Thestudy concluded that within the limits of this study, the TFA system caused less cracks then the full reciprocating system (Reciproc and WaveOne). Single‑file reciprocating files produced signifi- cantly more incomplete dentinal cracks than full‑sequence adaptive rotary motion.39 The TF Adaptive technique is basically a threefiletechnique,designedtotreatthema- jority of cases encountered in clinical prac- tice. Available are two sets of three file systems, one forsmall,calcifyingandseverelycurvedcanalsandone system for more ‘standard’ and larger canals, allowing adequate taper and increased apical preparation in bothscenarios.Thenumberofinstrumentswithineach sequence can also vary and adapt to canal anatomy, with the last instrument of the sequence used only Fig.7: M4 Safety Handpiece. Fig.8:TFTM AdaptiveTechnique Card. Size and Sequence Determination. Fig.7 Fig.8 32016