[Deformation evaluation of ProTaper nickel-titanium rotary instruments in curved canals instrumentation in vitro].
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To evaluate the deformation of ProTaper rotary instruments using in root canals of different curvature in vitro.Extracted first mandibular molars were divided into two experimental groups according to the curvature of mesial buccal canals: group A with moderate curvature and group B with severe curvature. Only the mesial buccal canals of all these teeth were prepared with 6 sets of new ProTaper rotary instruments individually. Additionally, the control group was established with a set of new ProTaper rotary instruments. After finishing each canal preparation, the instruments accompanied by control were examined under the stereomicroscope by an inspector without knowing the group. If distortion, unwinding, abrasion or fracture occurred within one set of instruments, then the whole set was disposed. The sets without problems were in use until 30 times. After 5, 10, 20 times canal preparation, S1, F1 files without deformation under stereomicroscope were examined under scanning electron microscope (SEM).Deformation of ProTaper rotary instruments happened after 12 times in group A and after 7 times in group B. In these two experimental groups, microcracks were found increasing with the times of use under SEM in the instruments without deformation under stereomicroscope. The microcracks on tip of instruments were deep in the early use and became smoother after 10 times. Similar changes happened on knife-edge of instruments, and the microcracks extended over the edge after 20 times use.Root canals with severe curvature tend to damage ProTaper rotary instruments more frequently than moderately curved canals. ProTaper rotary instruments are appropriate to treat less than 7 root canals with severe curvature or 12 root canals with moderate curvature. Stereomicroscope is recommended to detect early damages on Ni-Ti rotary instruments, for preventing instruments fracture in clinic.Keywords:
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Objective To increase clinical use times of ProTaper rotary nickel-titanium instruments by improvement of root canal preparation,which ensuring clinical effect at the same time.Methods A total of 162 human teeth including 23 front teeth,28 premolars and 111 molars were mainly managed with ProTaper rotary instruments followed by the sequence of root canal exploration,working length measurement,root canal dredging with hand file,coronal preflaring on the third of root canal with GG rotary files.Lateral condensation was used for root canal obturation.The effect of preparation and obturation were analyzed with radiographs before,during and after operation.Results ProTaper rotary instruments kept original shape of root canal very well,and endodontic flare-up seldom occurred.The most,lest and average root canal numbers prepared by all 9 series of ProTaper rotary instruments were 51,35 and 41 respectively.Type SX,S1,S2,F1,F2,F3 had been used to 19.4,43.3,43.3,43.2,38.3,6.7 root canals respectively.Finally,two series were broken,tip ends of two series were distorted and another five series showed aging differently on file blade and handle.Conclusions Improvement of root canal preparation,skillful practice,particular records and well-done storage guaranteed the increasement of clinical use count of ProTaper rotary nickel-titanium instruments.The suggestion is that no more than 35 root canals involving anterior and posterior teeth be prepared with ProTaper rotary instruments.
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To evaluate clinical effect of the new ProTaper Nickel-titanium rotary instruments in preparation of curved root canals.68 teeth with curved root canals were instrumented by ProTaper rotary instruments using crown-down technique, and by K files using step-back technique for control. All teeth were obturated with lateral condensation method. The efficiency of preparation and obturation was analyzed with radiographs before, during and after operation.No transportation, apical blockage and ledge were found in test. The technique could keep the curvature and flow of curved canals. There were two ledge and more apical transportation (P < 0.01) in control than in test. The operative time was shorter and post treatment pain seldom occurred in ProTaper group.The ProTaper NiTi rotary instruments can prepare curved root canals effectively and safely. It is an efficient instrumentation method for curved canals and can be used widely.
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Aim: This study evaluated the distortion and fracture mode of ProTaper and Mtwo rotary instruments following their use in severely curved root canals in extracted human teeth. Materials and Methods: A total of 30 mesial canals of mandibular molars were allocated into two groups that were balanced in terms of angle and radius of curvature. Canals were prepared by either ProTaper or Mtwo systems. Each set of instruments was changed after the third canal. Longitudinal and fractographic examinations of the instruments were carried out by scanning electron microscopy. Images were evaluated according to distortion and mode of fracture. Chi-square analysis and Fisher's exact test were carried out at a significance level of P Results: No significant difference was found between fracture and distortion percentage of ProTaper and Mtwo rotary instruments (P > 0.05). Fractographic analysis revealed that all of the Mtwo instruments demonstrated torsional failure and all but one of the ProTaper instruments (S1) showed torsional failure. Conclusion: Fractographic examination of the fractured surface revealed shear fracture was the predominant mode of failure. Root canal curvature was an essential parameter influencing the susceptibility of instruments to fracture.
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OBJECTIVE: To compare the performance of ProTaper® rotary instruments and stainless steel K-Flexofiles in preparing curved root canals in terms of changes in angle of curvature, apical transportation and production of canal aberrations and also to record the rate of separation of ProTaper® files.
STUDY DESIGN: Forty-one human mandibular first molars (mesial roots only each with 2 canals) with canal curvature of 15 to 18 degrees were divided into two groups. Forty-one canals were prepared using ProTaper® rotary instruments while forty-one canals were prepared using K-Flexofiles and Gates-Glidden drills. Digital radiographs obtained were analyzed with various image-analyzing programs. The parameters evaluated were reduction in canal curvature, apical transportation, lateral perforation, ledge, and apical zip, elbow, over-instrumentation and instrument separation. The statistical tests used were both independent and paired t-test, general linear models repeated measures, cross-tabulation with Pearson’s chi-square test and Fisher’s exact test. Significance level was set at 5% (α= 0.05).
RESULTS: Significant difference (P< 0.05) was found in the mean curvature reduction and in the occurrence of elbows. Five ProTaper® files fractured during canal preparation procedures; three of them were F3, and two were F2 instruments.
CONCLUSIONS: ProTaper® rotary instruments maintained the curvatures better and performed equally in terms of apical canal transportation, compared with stainless-steel instruments. For procedural errors and canal aberrations, ProTaper® instruments produced more elbows. Incidence of fractures was enhanced with increasing size of ProTaper® files, with most fractures occurring with file size #30 (F3) and #25 (F2).
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Abstract Aim To determine the cleaning effectiveness and shaping ability of ProTaper and RaCe nickel–titanium rotary instruments during the preparation of curved root canals in extracted human teeth. Methodology A total of 48 root canals of mandibular and maxillary molars with curvatures ranging between 25° and 35° were divided into two groups of 24 canals each. Based on radiographs taken prior to instrumentation with the initial instrument inserted into the canal, the groups were balanced with respect to the angle and the radius of canal curvature. Canals were prepared using a crown‐down preparation technique. After each instrument, the root canals were flushed with a 2.5% NaOCl solution and at the end of instrumentation with NaCl. Using pre‐ and post‐instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. After splitting the roots longitudinally, the amount of debris and smear layer was quantified on the basis of a numerical evaluation scale, using a scanning electron microscope (SEM). The data established for scoring the debris and the smear layer were separately recorded and analysed statistically using the Wilcoxon test. Results Two ProTaper and three RaCe instruments fractured; there was no significant difference between instrument types ( P > 0.05). Completely clean root canals were never observed. For debris removal, RaCe files achieved significantly better results ( P < 0.001) than ProTaper instruments. The results for remaining smear layer were similar and not significantly different ( P > 0.05). RaCe instruments maintained the original canal curvature significantly better ( P < 0.05) than ProTaper instruments. No significant differences were detected between the instruments ( P > 0.05) for the time taken to prepare the canals. Conclusions Under the conditions of this study, RaCe instruments resulted in relatively good cleaning and maintained the original curvature significantly better than ProTaper did.
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【Objective】To investigate the clinical effects of ProTaper Ni-Ti rotary instruments in preparation of curved root canals. 【Methods】 One hundred and eighty root canals of 180 patients were equally divided into two groups at random. The cases in experimental group were instrumented by ProTaper Ni-Ti rotary instruments using ProTaper technique(NT group); those in control group were instrumented by stainless steel hand K-files using Stepdown technique(SS group). The shape of root canalal and effects of obturation were evaluated with radio graphs during and after operation. The incidence of post-operative pain and the rate of instrument fracture were recorded. 【Results】The preparation time was(3.68±0.82) min in experimental group and(8.38±0.32) min in control group. The rate of root canal deformity after preparation was 9.32% in control group and 2.30% 93.12% of the canals in experiment group were obsturated as compared with 80.51% in control group. The incidence of post-operative pain were 10.00% in Ni-Ti roup while 37.50% in control group.【Conclusions】 Under clinical conditions, ProTaper NiTi rotary instruments can prepare root canal effectively and safely, the ProTaper Ni-Ti rotary instrumentation technique is an efficient root canal preparation method for curved canals. But fracture of the instrument should be avoided.
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Objective:This research aimed to study and evaluate clinical application of the using of two Nickel-titanium(NiTi)rotary instruments Mtwo and ProTaper,in preparation of molar root canals.Methods:60 molar root canals were instrumented by Mtwo or ProTaper rotary instruments in test groups and by stainless steel K files in control group.All teeth were obturated with lateral condensation method.The efficiency of preparation was analyzed by radiographs before and after treatment.The operating time and the incidence of complications were recorded.Results:Two NiTi rotary instruments could keep the curvature and flow of curved canals very well,and the continuously tapered root canal shape was achieved.There were no transportation,apical blockage,and ledge in all test groups.The operative time of Mtwo was shorter than that of ProTaper.Two ProTaper rotary instruments fractured in canals.Conclusion:With the NiTi rotary instruments,Mtwo instruments can be prepared as effectively and quickly as ProTaper instruments.Meanwhile,Mtwo instruments was as safe as ProTaper instruments.
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Objective To evaluate the effect of hand-used ProTaper instruments in preparation of curved root canals. Methods Forty teeth with curved root cananls were randomly divided into 2 groups of 20 specimens each. One group was prepared by hand-used ProTaper with crown-down technique. The control group was instrumented by K-files with step-back technique. The canals were obturated using lateral condensation technique in both groups. The efficiency of preparation and obturation of root canals was analyzed with radiographs pre-, during and post- instrumentation. Results No transportation, apical blockage, ledge and instrument fractures were occurred with hand-used ProTaper instruments and the original curvature was maintained well. The operating time was shorter and post-treatment pain seldom occurred in hand-used ProTaper group. Conclusion Hand-used ProTaper instruments were proved to be efficient and time-saving in preparing curved root canals.
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Objective:To evaluate the clinical effect of a set of nickel-titanium rotary instruments,named ProTaper,in preparing curved root canals of the aged.Methods:Eighty-two posterior teeth of aged people with curved root canals were randomly divided into two groups.The 41 teeth in experiment group were managed by ProTaper nickel-titanium rotary instruments using crown-down technique;while the 41 teeth in control group by stainless steel K files.All teeth were obturated with lateral condensation method.The effects of preparation and obturation with radiographs before,during and after operation were analyzed.Results:Compared with the control group,the nickel-titanium rotary instruments kept the curvature and flow of curved canals very well,and the continuously tapered root canal shape was achieved in all cases.The time of operation was short and endodontic flare-up seldom occurred.However,the test group had two fractured files.Conclusion:The ProTaper nickel-titanium rotary instruments can prepare curved root canals effectively and quickly.Meanwhile,the problem of instrument separation due to many reasons such as variations in canal anatomy and fatigue of instruments should be prevented.
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The cyclic resistance of ProTaper Universal (size 25/08) and ProTaper Next (size 25/06) instruments was compared in artificial canals with different curvatures in this study. A total of 30 ProTaper Universal and 30 ProTaper Next instruments were divided into 6 groups (n = 10) and were operated into artificial canals with 3 different angles of curvature (45°, 60°, 90°). The canal length was kept consistent in this study. The number of cycles to fracture (NCF) was counted until file fracture occurred, at which point, the length of the fragment was measured. The data were analyzed statistically using ANOVA complemented by the Tukey test (p < 0.05). Cross sections of the fractured files were scanned by an electron microscope. In the fatigue test, the ProTaper Next displayed more resistance in 45° and 60° canals (p < 0.05), whereas ProTaper Universal exhibited a better operability in 90° canals (p < 0.05). The average length of the fragments from ProTaper Next was significantly shorter than that from ProTaper Universal in 90° canals (p < 0.05). The cross sections of the fractured surfaces became flatter when the curvature angles decreased from 90° to 45°. ProTaper Next was more reliable when shaping in curved canals, whereas ProTaper Universal was more sui for the preparation of root canals with severe curvatures.
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