| کلیدواژههای انگلیسی مقاله |
Flare-up, Nano sealer, AH-26 Sealer, IntroductionThe main objectives of root canal therapy are to achieve long-term comfort, function, and aesthetics for the patients and prevention of reinfection of tooth. These objectives are provided through complete cleaning, shaping, and obturation of canals of affected teeth [ 1, ]. However, some patients may report moderate-to-severe pain and/or swelling following root canal treatment that is detrimental for both patient and dentist and may entail an unscheduled emergency visit by patients to relieve their symptoms. The rate of flare-up following root canal therapy (RCT) has been reported to range from 2.53% to 58% [ 2, ]. Pack et al. reported 40% of the patients had post-operative pain 24 hours after RCT and this decreased to 11% after one week [ 3, ]. Although the exact reasons for flare-up are not clearly understood, it is accepted that flare-up is a multi-factorial phenomenon and there is no single reason for its occurrence [ 4, ]. Microbiological, chemical, mechanical, and host variables can induce pain and swelling following root canal treatment [ 5, ]. In addition, history of preoperative pain, gender and age factors, the pre-operative pulp status, the type of tooth, the type of treatment (initial or re-treatment), and a history of allergy may all influence the rate of flare-up [ 6, ]. In addition, some studies have demonstrated the effect of several factors such as instrumentation technique, type of analgesic, method of analgesic prescription, type of rotary instrument, anesthetic solution, occlusal reduction, and method of root canal filing on incidence of flare up [ 7, - 8, ]. In obturation of the root canal system, sealer is used to prevent penetration of microorganisms and their byproducts. In the other hand, sealer is in direct contact with periapical tissues and may cause inflammation, tissue degeneration, and delay in wound healing. Therefore, the ideal root canal sealer should be non-cytotoxic, non-mutagenic, and immunologically compatible with periapical tissues [ 9, ]. Currently, a large variety of sealers with different formulas and physical properties are available for use. However, they all have their limitations. It is difficult to produce a sealer with proper physicochemical properties while being biocompatible for long-term. For many years, zinc oxide-eugenol (ZOE)-based sealers have been widely used in endodontic practice. The use of nanotechnology has allowed many developments in dentistry and advances in oral-health-related nano material and therapeutic methods [ 10, ]. Some of the advantages of using nano particles in endodontic sealers include improving their physicochemical characteristics, enhancing the antibacterial property, better penetration into the dental tubules, decreasing microleakage, and increasing biocompatibility [ 11, - 12, ]. It has been shown that incorporating zinc oxide nano particles enhances the physicochemical characteristics (setting time, flow, solubility, dimensional stability, and radiopacity) of Grossman sealer [ 12, ]. Kesler Shvero&,nbsp et al.&,nbsp [ 13, ] demonstrated that epoxy resin-based surfaces with cationic nano particles attracted and sacrificed Enterococcus faecalis. DaSilva&,nbsp et al.&,nbsp [ 14, ] showed that incorporating chitosan nano particles into ZOE sealer reduced the formation of biofilm within the sealer-dentin interface. In addition, it has been reported that nano-ceramic sealer had better cytocompatibility compared to Endoseal MTA considering the effects on cell spreading and proliferation [ 15, ].Recently, a new endodontic sealer with nano-sized ZO powder particles (NZOE) has been developed in the Dental Material Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. This sealer is similar to various ZOE-based sealers, but with different sizes of ZOE nanoparticles. In previously published articles, we verified that NZOE sealer had less microleakage and better antibacterial property in comparison with Pulpdent and AH-26 sealers [ 16, ]. In an animal study, it was observed that the histocompatibility properties of NZOE were comparable to the above-mentioned commercial sealers [ 17, ]. Moreover, the cytotoxicity of NZOE on murine L929 cell line was comparable to that of Pulpdent and was lower than AH-26 sealer [ 18, ]. In another study, the cytotoxicity of NZOE sealer on human gingival fibroblasts isolated from healthy subjects was evaluated and NZOE exhibited lower cytotoxicity compared to Pulpdent and AH-26 [ 19, ]. ZOE -based sealers are the oldest sealer used in endodontic therapy. Zinc oxide (ZO) is a valuable component of these sealers that is very effective as an antimicrobial agent. Many reforms have been done on these sealers in order to improve their properties and many commercial models are available [ 20, ].&,nbsp In addition, ZOE-based cements have been found to possess favorable characteristics in terms of biocompatibility [ 19, - 20, ].To the best of our knowledge, the use of nano-structured materials as sealers in root canal therapy is limited to two or three types of nano-structured hydroxyapatite alone or in combination with epoxy resin (Nanoseal) [ 20, - 22, ].No evidence-based investigations have evaluated postoperative pain and swelling when different sealers are used for obturation. The aim of this study was to assess postoperative pain and swelling in a prospective randomized clinical trial following the use of AH-26 and NZOE as a sealer in mandibular molars with irreversible pulpitis that were treated in one visit.Materials and MethodThe Ethics Committee of Mashhad University of Medical Sciences (Ir.mums.dentistry.rec.1397.044 and Iranian Registry of Clinical Trials ID No. IRCT2018071136542) approved the protocol of this study.Synthesis of ZnO nano-particlesIn this work, ZnO nano-powders were prepared by a modified sol-gel method, using gelatin [ 23, ].To prepare 5 g of the final product, first a solution of gelatin (type B from bovine skin, Sigma Aldrich) was prepared by dissolving 10 g of gelatin in 150 mL of deionized water at 60&,deg C. Then, appropriate amounts of zinc nitrate (Zn (NO3)2&,nbsp .6H2O Merck %99) were dissolved in minimum deionized water at room temperature. Then, the two solutions were mixed and stirred for 8 hours while the temperature was kept at 80&,deg C. Finally, the pure resins were calcined at different temperatures of 500, 600, and 700&,deg C to obtain ZnO nano-powders. Morphological and structural properties of the prepared ZnO were characterized by x-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques.Procedural stepsThe sample size was calculated based on an alpha of 0.05 with power of 80%, indicating that 27 patients would be required in each group but after considering the dropout rate of 10%, the sample size increase to 30 patients in each group. Inclusion criteria were as follows, individuals without systemic diseases and with a &,#64257 rst mandibular molar diagnosed with irreversible pulpitis due to caries, no sinus track and abscess, normal periapical radiographic appearance, no spontaneous pre-treatment pain, not having taken any medication for at least 8 h before the treatment visit. Patients of both genders ranging from 20 to 50 years of age were selected. During the root canal procedure, teeth that could not be treated in a single visit or patients who interrupted treatment were excluded. In addition, the patient with severe periodontal disease, over instrumentation or over&,#64257 lling beyond the root canal space, teeth that could not be isolated with rubber dam, root canal calci&,#64257 cation, root resorption and teeth that were not suitable for further restoration were excluded. All the treatment procedures were performed by a postgraduate student in the Endodontic Department, Mashhad Dental School, Iran, from May to August 2018. A total of 60 teeth were randomly assigned to two groups using a random-digit table. Before initiating treatment, the patients were asked to rate their pre-treatment pain on a visual analogue scale from 0 to 9. For each number, one of the sealers was selected. Each patient chose one of the numbers, and based on the number, the nurse supplied one of the sealers for the treatment visit. Since two sealers were different in their shape and appearance, the practitioner could not be blind. Prior to beginning of the root canal treatment, inferior alveolar nerve block injection was done with 2% lidocaine with 1, 80 000 epinephrine. After isolation with a rubber dam, followed by access cavity preparation, working length was determined with a Raypex6 apex locator (VDW, Munich Germany) and then it was con&,#64257 rmed radiographically. After preparing the root canals with hand instruments to at least a size 15 K-&,#64257 le (Mani, Togichi Japan), Hero rotary instruments (Micro-Mega, Besan&,ccedil on France) were used for root canal preparation. Apical patency was performed with a size 10 K-&,#64257 le between each rotary instrument. The apical preparation was completed up to size 30, .04 taper. Between instruments, the root canals were irrigated with 3 mL of 5.25% NaOCl with a 30-gauge side perforated needle (Endo-Top, PPH Cerkamed, Stalowa Wola Poland). During irrigation, the needle was repeatedly moved up and down to prevent locking in the canals. The smear layer was removed by irrigating with 3 mL 17% Ethylene diamine tetra acetic acid (EDTA) (Asia Chemi Teb Co., Tehran, Iran) followed by 5 mL normal saline irrigation at the end of root canal preparation. The root canals were dried with paper points (Meta Biomed Co., Chungcheongbuk Korea). Then in the group 1, the canals were &,#64257 lled with gutta-percha (Meta Biomed Co.) and AH26 (Dentsply DeTrey, Konstanz Germany) sealer and group 2 was filled with gutta-percha and NZOE sealer using the cold lateral condensation technique. Each patient was given a numerical visual analogue scale (VAS) form to record the severity of pain from 0 to 9 during the 6, 18, 24, and 48-hours period following treatment, and the other form was used to record swelling. In the second form, the following scores were used, 0 for none swelling, and 1 for swelling. The data were analyzed using SPSS v.19 software applying Chi-square and Kendall&,rsquo s Tau-b. The significance level was set at 0.05.ResultsBased on the inclusion and exclusion criteria, a total of 64 patients were eligible to participate in the study. Four patients from both groups were excluded from study since treatment could not be completed in one visit for one patient two patients did not return the VAS form, and one patient had partial necrosis pulp. Finally, 60 patients were included for data analysis (30 in each group. The age and sex distribution of patient in each group was reported in Table 1,. The two groups were similar according to distribution of age and gender of the patients. None of the patients had pain on palpation, percussion and spontaneous pain at the treatment visit. The results showed that at the 24 h following treatment, the patients receiving NZOE as the sealer had experienced statistically signi&,#64257 cant lower pain compared to those who had AH 26 (p= 0.003) no signi&,#64257 cant difference was found between the group for the rest of the study defined time periods (Table 2,). None of the patient in both groups had swelling during the 48 h period following treatment.Variable AH-26NZOETotalp ValueN(%)N(%)N(%)Age 20-34 years16(53.3)16(53.3)32(53.3)1.0035-50 years14(46.7)14(46.7)28(46.7)Sex Male 15(50)14(53.3)29(48.3)0.796Female 15(50)16(46.7)31(51.7) N,Number |