Comparison Of The Shaping Capability Of Reciprocating Instruments In Simulated Canals And The Effect Of Reciprocating Instruments In Clinical Application

Objective:1.This study aims to evaluate the preparation time,cutting amount and shaping capability of ProTaper,WaveOne,M3-One nickeltitanium instruments in simulated root canals,and provide experimental basis for better selection of root canal preparation nickel titanium instrument in clinical practice2.To compare the clinical application of ProTaper,WaveOne and M3-One nickel-titanium instruments in patients with the situation of degree of pain and provide reference for clinical treatment of nickel-titanium instruments for root canal preparation.Methods:1.30 resin simulation root canal is compiled into No.1-30,which is divided into 3 groups by random number table method.ProTaper group,WaveOne group,M3-One group.2.That resin simulate root canal is marked before root canal preparation,the weight of the resin simulate root canal preparation is obtained by weighing the resin simulated root canal preparation by an electronic balance in an ultra-clean environment,the weight of the resin simulate root canal preparation is weighed again after the root canal preparation is completed,and the difference between the weight before and after the root canal preparation is the cutting amount of a nickel-titanium root canal preparation instrument.3.The root canal preparation procedure shall be carried out strictly in accordance with the manufacturer's instructions,and all nickel-titanium instruments shall be used with the x-smart plus motor mounted on the 6:1 deceleration reverse angle mobile phone.Nickel titanium instruments into the root canal before dipping in 17%EDTA gel,each instrument after the completion of the preparation,with 75% alcohol cotton ball to wipe the surface of the instrument,5ml 5.25% sodium hypochlorite rinse flush root canal,accompanied by back file at the same time.After the root canal preparation is completed,the paper is twisted and sucked dry and dried naturally at room temperature.All instruments were prepared for 5 root canals and then discarded.all operations were performed by the same physician.The time from entry to complete exit of each nitinol instrument was recorded by another physician.4.Using scanner to obtain 3 groups of images before and after the root canal preparation,using adobe Photoshop CS6 and image j software to overlap the images before and after the root canal preparation and measure the deviation before and after the root canal preparation,1 mm away from the root tip hole,every 1 mm as an observation point,a total of 9 observation points,measuring the root canal inside and outside wall resin removal,compare the center positioning ability of the five groups of instruments.5.Choose clinical diagnosis for pulpitis or chronic periapical periodontitis in 30 patients.The patients were randomly divided into three groups according to the order of treatment.ProTaper,WaveOne and M3-One were used for root canal preparation respectively.after the root canal preparation,the patients were informed that if there was any acute pain or swelling,they should be followed up at any time.The pain was recorded by telephone 24 hours after operation.A week later,return visit,record the occurrence of pain.The clinical effect was evaluated by the occurrence and degree of pain between diagnosis.6.After the three groups of patients reached the root filling standard,root filling was carried out,and x-ray films were taken.the root filling films were scored by three dental pulp doctors by blind method.Results:1 Time for root canal preparationThe root canal preparation time was 218.5±6.7s in ProTaper group,67.2±6.9s in WaveOne group and 58.3±3.2s in M3-One group.The single-factor variance analysis showed that the root canal preparation time of the two groups of reciprocating nickel-titanium instruments was shorter than ProTaper(P< 0.05).there was no statistical difference between the two groups of reciprocating nickel-titanium instruments(P> 0.05).2.The resin cutting amount of nickel titanium instrumentThe resin cutting capacity of Pro Taper group was 12.4±2.1 mg,WaveOne group was 7.3±1.2 mg,M3-One group was 5.6±1.1 mg.M3-One have the least resin cutting,ProTaper have the largest resin cutting,the difference was statistically significant(P< 0.05).3 Center positioning capability of nickel-titanium instrumentThe results showed that the central positioning ability of the instrument was different at the distance of 1 mm,2 mm,4-6 mm from the heel tip hole,and had statistical significance.WaveOne,M3-One were better than ProTaper(P<0.05).M3-One showed better ability of central positioning than WaveOne(P< 0.05).4.The occurrence of pain between diagnosisThe results showed that no IIIgrade pain occurred in all three groups 24 hours after root canal preparation and one week after follow-up.There was no difference between WaveOne group and M3-One group in the pain of 24 hours and 1 week follow-up visit(P> 0.05).5.Evaluation of root filling effectThe results showed that the three nickel-titanium instruments could keep the original shape of the root canal well,and had no obvious root canal deviation and root tip step appearance.all the three sets of nickel-titanium instruments achieved good root filling effect.There was no significant difference among the three groups.Conclusion:1.The reciprocating nitinol instrument reduces the time of root canal preparation and improves the efficiency of root canal preparation.2.In the experiment of root canal forming ability,reciprocating nitinol instrument has better ability to locate the center of root canal and less tissue cutting capacity than continuous rotating nitinol instrument.3.The domestic reciprocating nitinol m3-one also achieved good root canal preparation effect.4.In clinical application,after the use of reciprocating nickel-titanium instrument root canal preparation,there is no difference between the patient's diagnosis of pain and continuous rotating instrument group,and can achieve better root filling effect.