| Background and ObjectiveRoot canal therapy is an effective treatment for pulpitis and periodontitis,and root canal preparation is the key to success.Root canal preparation mainly refers to form a shape conducive to root canal filling,and clean the root canal as much as possible.However,mechanical root canal preparation is easy to form smear layer in the inner wall of the root canal.The smear layer not only provides a favorable living environment for bacteria,but also reduces the closeness between the root canal blocking material and the inner wall of the root canal,resulting in apical microleakage,which is an important cause of root canal reinfection.Therefore,the removal of smear layer can reduce the risk of root canal reinfection and improve the long-term effect of root canal therapy.At present,the techniques used for root canal irrigation such as needle irrigation technology,passive ultrasonic irrigation technology,acoustic irrigation technology,laser activation technology can remove the smear layer to a certain extent.One of the purposes of our study was to compare the effects of needle irrigation,passive ultrasonic irrigation,EDDY irrigation and PIPS-Er:YAG laser irrigation on the removal of smear layer,so as to provide theoretical basis for clinical treatment.At the same time,due to the different working principles of different irrigation equipment,the irrigating fluid,tissue debris,bacteria and toxins may be squeezed out of the apical foramen to a certain extent,resulting in acute inflammation around the apical.As a result,the original symptoms of the patients can not be effectively relieved or even aggravated.Patients with symptomatic pulpitis often have more urgent needs for curing because of severe pain,and hope to relieve the pain as short a time as possible.The second purpose of our study was to compare the effects of needle irrigation,passive ultrasonic irrigation,EDDY irrigation and PIPS-Er:YAG laser irrigation on postoperative pain in patients with symptomatic irreversible pulpitis.So as to provide reference for the selection of clinical irrigation equipment.Methods1.Sixty mandibular premolars extracted from patients in Oral and Maxillofacial Surgery in our hospital from June 2020 to December 2020 were selected.All the crowns of the single-root human teeth were cut off and the root length was kept to 15mm.The specimens were instrumented with ProTaper Universal Ni-Ti files.Then they were randomly divided into four groups according to irrigation techniques:needle irrigation(NI),passive ultrasonic irrigation(PUI),EDDY irrigation(EDDY)and PIPS-Er:YAG laser irrigation(PIPS).Finally,the roots were split longitudinally and the half of the complete shape was taken.The smear layer in the labeled area of the root was observed and photographed under scanning electron microscope.Finally,the smear layer score was assessed using the scanning electron microscope images and then and statistical analysis were carried out.2.A total of 96 patients with symptomatic irreversible pulpitis were selected in our hospital from September 2019 to December 2020.The basic information and the pain level of all patients were recorded before operation,then the pulp was opened and the length was measured under routine local anesthesia,and the root canals were prepared to F4 with ProTaper Universal Ni-Ti files.Then they were divided into four groups according to different root canal irrigation techniques:needle irrigation(NI)group,passive ultrasonic irrigation(PUI)group,EDDY irrigation(EDDY)group and PIPS-Er:YAG laser irrigation(PIPS)group.Then the root canals were all filled with hot gutta percha and resin-based root canal paste,and the crown defects were repaired with 3M nano resin.After that,the VAS of all patients was assessed at 8h,24h,48h,and 7 days postoperatively and the use of painkillers was recorded.The pain level and the intake of painkillers in different time after root canal therapy were compared in each group.Results1.In vitro study:The smear layer score increased gradually from the coronal part to the apical part of the root canal.Except for the PIPS group,there was significant difference between the coronal part and the apical part of the root canal(P<0.05).In the coronal part of the root canal,the smear layer score was similar among the four groups(P>0.05).In the middle and apical part of the canal,the smear layer score in PUI group,EDDY group and PIPS group were significantly lower than those in NI group(P<0.05).There was no significant difference between PUI and EDDY group(P>0.05).In the apical part of the canal,the smear layer score in PIPS group was lower than that of other groups(P<0.05).2.Clinical trial:The VAS of the patients in PUI group was significantly lower than that of NI group(P<0.05)at 8 hours after root canal treatment,but there was no significant difference among other groups(P>0.05).The VAS of the patients in EDDY group was significantly lower than that in NI group(P<0.05)at 24 hours,but there was no significant difference among other groups(P>0.05).And there was no significant difference among the VAS of the patients in the four groups at 48 hours and 7 days after root canal treatment(P>0.05).The highest postoperative VAS was recorded at 8 hours after root canal treatment,and decreased gradually with the time went by.There was no significant difference in the intake of painkillers among the patients in the four groups(P>0.05).Conclusion1.The cleaning effect of passive ultrasonic irrigation technology is similar to that of EDDY irrigation technology.They were both better than that of needle irrigation technology.PIPS-Er:YAG laser irrigation technology can effectively remove the smear layer of the apical part of root canals.2.Compared with needle irrigation technology,passive ultrasonic irrigation technology and EDDY irrigation technology can reduce the postoperative pain level of patients with symptomatic irreversible pulpitis within 24 hours,while PIPS-Er:YAG laser irrigation technology has the same effect. |
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