| Objective At present,the root canal preparation in the clinic is not a step of flushing the sputum needle.In the previous study,we found that continuous rinsing of the sputum needle during the preparation of the root canal with Nitinol can increase its folding resistance.The fracture of Ni-Ti-tantalum can be divided into bending fracture and torsion fracture.In this study,the dynamic and static bending fatigue test model of Ni-Ti-tantalum under the rinsing condition is established and the different flow rates,different angles,different positions and different The effect of temperature on the dynamic and static cyclic bending fatigue of rotating Ni Ti.Methods A closed experimental environment was constructed and the experiment was started when the thermometer measured the indoor temperature at 24 ?.The rinse solution is distilled water(deionized water).The lowest and highest flow rates of the measuring cup pumping system are 25ml/min and 140ml/min respectively,which is defined as the small flow and large flow of the experiment.The angles of the water flow and the nitinol were determined to be 15° and 90°,respectively,which were defined as the two flushing angles of the experiment.The glass tube can be covered above the metal root tube to make the metal root tube semi-closed or fully enclosed.Nickel-titanium niobium is defined as the research site at the maximum bend of the metal root canal and the metal root canal.According to the experiment,the pump system can pump the liquid of different temperatures stored in the constant temperature water bath.A stainless steel test platform was fabricated comprising a metal root canal with a semicircular curved root canal with a diameter of 2 mm,a curvature angle of 90° and a radius of curvature of 5 mm.The motor of the X-Smart plus machine sets the speed of 250r/min,the maximum torque is 1.5Ncm,and the movement mode rotates clockwise.The motor handle was fixed using three fasteners,and the nitinol was placed into a metal mold of 18 mm(straight line portion 13 mm,curved portion 5 mm),in which it was free to rotate.In the static experiment,the nickel-titanium tantalum has no displacement in the axial direction;in the dynamic experiment,pulling D can make the nickel-titanium tantalum produce 5mm reciprocating displacement in the axial direction.The blank(control) group was recorded separately,the maximum bending point was 15°25ml/min,the maximum bending point was 15°140ml/min,the maximum bending point was 90°25ml/min,the maximum bending point was 90°140ml/min,and the root bending point was 15°.25ml/min,90°140ml/min7 static nickel-titanium before rotation(TtF);blank group,24? distilled water 25ml/min,10? distilled water 25ml/min,24? distilled water 140ml/min,24 ? 0.5% NaClO 25 ml / min,24 ? 0.5% NaClO 140 ml / min,24 ? 1% NaClO 25 ml / min,24 ? 5% NaClO 25 ml / min 8 group of dynamic Ni-Ti ? pre-breaking rotation time(TtF).Results The static TtF of 15°25 ml/min at the maximum bend is(113.60±8.32)s;the static TtF at the maximum bend of 15°140ml/min is(109.95±18.63)s;the maximum bend is static at 90°25 ml/min.The TtF is(111.00±16.28)s;the static TtF of 90°140ml/min at the maximum bend is(110.95±17.25)s;the static TtF of the root canal 15°25 ml/min is(105.05±13.30)s;The static TtF of 15°140ml/min is(113.80±16.12)s;the dynamic TtF of the blank group is(218.55±25.85)s,and the dynamic TtF of 25 ml/min distilled water is(270.40±29.90)s,10? distilled water.The dynamic TtF of 25ml/min is(295.70±41.93)s,the dynamic TtF of 240ml/min of distilled water at 24? is(284.65±46.77)s,and the dynamic TtF of 24? 0.5% NaClO25ml/min is(289.05±33.44)s,24 The dynamic TtF of ?0.5% NaClO140ml/min is(282.25±39.09)s,the dynamic TtF of 24%C1% NaClO25ml/min is(236.90±31.08)s,and the dynamic TtF of 24?5%NaClO25ml/min is(214.80±29.68).)sConclusions 1.Under the experimental conditions,whether dynamic or static,the TtF under the rinsing conditions is far greater than that under no rinsing conditions,indicating that the rinsing can increase the bending fatigue resistance of Nitinol.2.Under the experimental conditions,the flushing will increase the flexural fatigue resistance of Nitinol,which can increase its bending fatigue resistance and the same performance.3.Under the experimental conditions,the flushing will increase the flexural fatigue resistance of Nitinol.At high flow rates,there is no statistical difference between the two positions;at small flow rates,there is a difference between the two flushing positions,at the maximum bending The flushing is better than the flushing at the root canal.4.Under the experimental conditions,the flushing will increase the flexural fatigue resistance of Nitinol.This experiment shows that the flow rate of the flushing can increase its bending fatigue resistance and the same efficiency.5.Under the experimental conditions,the simultaneous flushing of nickel-titanium niobium in the preparation of root canal will improve its bending fatigue resistance;the dynamic non-flushing bending fatigue performance of Ni Ti is better than the static anti-bending fatigue performance of washing;dynamic experiment The simultaneous flushing of the nickel-titanium-niobium prepared root can also improve its bending fatigue resistance;in the dynamic experiment,the flushing fatigue performance is not further improved when the flushing flow rate is further increased.6.Under the experimental conditions,the simultaneous flushing of 0.5% NaClO solution will increase the dynamic bending fatigue resistance of Nitinol.The 1% and 5% NaClO solution washing will not increase the dynamic bending fatigue resistance of Nitinol.7.Under the conditions of this experiment.Flushing with a water flow of 10 ? and 24 ? will increase the bending fatigue resistance of Ni-Ti,and there is also a statistically significant difference between 10 ? and 24 ?,which indicates that low temperature can increase the flexural fatigue resistance of Nitinol.And the lower the temperature,the more obvious the effect. |
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