Effect of three nickel-titanium rotary file techniques on infected root dentin reduction. Influence of the NiTi rotary system on the debridement quality of the root canal space. A retrospective study of endodontic treatment outcome between nickel-titanium rotary and stainless steel hand filing techniques. A comparison of Profile, Hero 642, and K3 instrumentation systems in teeth using digital imaging analysis. Ability of chemomechanical preparation with either rotary instruments or self-adjusting file to disinfect oval-shaped root canals. Ex vivo study on root canal instrumentation of two rotary nickel-titanium systems in comparison to stainless steel hand instruments. Microbiological assessment of root canals following use of rotary and manual instruments in primary molars. Comparison among manual instruments and PathFile and Mtwo rotary instruments to create a glide path in the root canal preparation of curved canals. Comparison of curved canals preparations using profile, GT and Hero 642 rotary files. Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. An in-vitro Evaluation of canal transportation and centering ability of two rotary Nickel Titanium systems (Twisted Files and Hyflex files) with conventional stainless Steel hand K-flexofiles by using Spiral Computed Tomography. Comparison of canal transportation and centering ability of twisted files, Pathfile-ProTaper system, and stainless steel hand K-files by using computed tomography. Bacterial reduction with nickel-titanium rotary instrumentation. Reduction in intracanal bacteria during root canal preparation with and without apical enlargement. Nickel-titanium rotary instrument fracture: a clinical practice assessment. Comparison of the cleaning capacity of Mtwo and Pro Taper rotary systems and manual instruments in primary teeth Rotary Mtwo system versus manual K-file instruments: efficacy in preparing primary and permanent molar root canals. In vivo determination of root canal length: a preliminary report using the Tri Auto ZX apex-locating handpiece. In vitro investigation of the cleaning efficacy, shaping ability, preparation time and file deformation of continuous rotary, reciprocating rotary and manual instrumentations in primary molars Treatment of Necrotic Teeth Using Two Engine-Driven Systems and Patient’s Postoperative Pain: A Double-Blind Clinical Trial Root Canal Cleaning Efficacy of Rotary and Hand Files Instrumentation in Primary Molars A comparative study of biofilm removal with hand, rotary nickel-titanium, and self-adjusting file instrumentation using a novel in vitro biofilm model. Bacteriemia during endodontic treatment in relation to the technique of biomechanical preparation: randomized clinical trial.
OBJECTIVE This study compared the bacterial reduction of in vitro infected root canals after instrumentation by 3 nickel-titanium ( NiTi ) rotary files with different taper and diameter versus manual stainless steel files . STUDY DESIGN Sixty-four single-rooted human teeth were infected with a suspension of Streptococcus sanguis measured by optical density . Teeth were divided r and omly into 4 groups of 16 and prepared with Flexofiles , GT rotary files , HERO 642 , and ProFile . Bacterial samplings were performed before ( S1 ) , during ( S2-S3 ) , and after ( S4 ) instrumentation . RESULTS All techniques significantly reduced the number of bacterial cells in the root canals ( P < .05 ) . There was no significant difference between NiTi and manual instrumentation at S2 , S3 , or S4 . Concerning bacterial reduction , the results suggest that a manual stainless steel file preparation is as efficient as a NiTi rotary instrumentation . CONCLUSION Regardless of the root canal preparation technique , its taper , and diameter , the root dentin remained infected and was not bacteria-free at the end of the experiment OBJECTIVE The present study was design ed to test the null hypothesis that there is no significant difference in debridement quality promoted by 3 nickel-titanium ( NiTi ) rotary systems . STUDY DESIGN Sixty-seven vital m and ibular molars that were prospect ively collected in vivo were used . The teeth were extracted and then pulp tissue fixed by 10 % formalin . The use of different NiTi rotary systems result ed in 3 experimental groups with 20 specimens each : G1 : Hero 642 ; G2 : K3 ; and G3 : ProTaper Universal . Afterward , the specimens were histologically prepared and serial 0.5 microm cross-sections were obtained every 0.2 mm from the 1 - 3 mm apical levels . The remaining pulp tissue was assessed using a morphometric approach . The cross-sectional area of each root canal and remaining pulp tissue were measured ( mcirom(2 ) ) . Thus , the percentages of remaining pulp tissue area were calculated for each root canal . RESULTS Overall , the pooled data obtained from all levels revealed a variable amount of remaining pulp tissue for all experimental groups . Remaining pulp tissue existed in every specimen . However , the Kruskal-Wallis H test was unable to show significant differences among the experimental groups ( P > .05 ) for the pooled data from all levels . CONCLUSIONS The present study did not find a significant difference in the quality of canal debridement between different NiTi rotary systems , because an adequate tapered shape is obtained AIM The purpose of this study was to compare the periapical healing of molar root canal treatment using two instrumentation techniques . METHODS A total of 225 maxillary and m and ibular first and second permanent molars endodontically treated by undergraduate or postgraduate students were r and omly selected from a computerized hospital data base of which 110 molars had been prepared using a hybrid rotary technique with nickel-titanium instruments ( group NR ) and 115 with h and stainless steel files ( group HF ) . Patients were recalled and the teeth were examined both clinical ly and radiographically for signs of periapical inflammation . RESULTS Some 19 % and 39 % of teeth in the NR and HF group , respectively , were judged to have some form of procedural errors . A higher rate of periapical healing was noted for NR ( 77 % ) than the HF group ( 60 % ) ( p < 0.05 ) . Factors contributing favorably to treatment outcome included the use of rotary technique , maxillary molar , experienced operator , and absence of preoperative radiolucent lesion . CONCLUSION There was a higher incidence of procedural errors and a lower success rate for primary root canal treatment of teeth prepared with stainless steel files compared with the use of NiTi instruments in a continuous reaming action OBJECTIVE To evaluate the changes in cross-sectional area morphology of curved canals after instrumentation with Profile((R ) ) , Hero 642((R ) ) , and K3((R ) ) using digital imaging analysis . Study design Thirty mesial m and ibular curved canals were used ( 25 - 40 degrees ) . The molars were embedded in resin and the roots were sectioned transversely at three levels : apical , middle , and coronal . The canals were r and omly distributed into 3 groups for instrumentation using Profile.04 and .06 , Hero 642 , and K3 . The pre- and postinstrumentation sections were digitized and areas corresponding to the canals were measured with image-processing software . RESULTS Hero  eliminated significantly more dentine than K3 and Profile in all 3 sections ( P < .01 , ANOVA test ) , with no differences observed between the latter 2 systems ( P > .05 , Student-Newman-Keuls test ) . All 3 systems yielded a rounded canal morphology in the coronal , middle , and apical thirds . CONCLUSION Hero rotary instruments produced more changes in cross-sectional area of the root canal INTRODUCTION Oval-shaped root canals might represent a great challenge for proper disinfection . This study compared the capability of a newly developed instrument , the self-adjusting file ( SAF ) , and rotary nickel-titanium ( NiTi ) instrumentation to eliminate Enterococcus faecalis population s from long oval root canals of extracted human teeth . As a secondary purpose , the ability of a modification in sampling technique to recover bacteria lodged in recesses of oval canals was evaluated . METHODS Long oval canals from m and ibular incisors and maxillary second premolars were infected with E. faecalis ( ATCC 29212 ) for 30 days and then r and omly distributed into 2 experimental groups . In group 1 , canals were prepared up to a 40/04 rotary BioRaCe instrument by using irrigation with NaviTip needles ; in group 2 , canals were prepared by using the SAF system with continuous irrigation . NaOCl and ethylenediaminetetraacetic acid were used as irrigants . Bacteriologic sample s were taken before ( S1 ) and after preparation ( S2a and S2b ) . RESULTS Reduction in the bacterial population s was highly significant in both groups ( P < .001 ) . Preparation of long oval canals with the SAF was significantly more effective than rotary NiTi instrumentation in reducing intracanal E. faecalis counts ( P = .01 ) . Frequency of positive cultures in S2 sample s was 11 of 20 ( 55 % ) for rotary instrumentation and 4 of 20 ( 20 % ) for SAF instrumentation ( P = .048 ) . S2b sample s ( modified method ) yielded more positive sample s than S2a ( 12/40 vs 5/40 ) , but this difference reached no statistical significance ( P > .05 ) . CONCLUSIONS The SAF system was significantly more effective than rotary NiTi instrumentation used with syringe/needle irrigation in disinfecting long oval root canals in vitro . A modified sampling technique might be necessary for oval canals AIM To investigate instrumentation time , working safety and the shaping ability of two rotary nickel-titanium ( NiTi ) systems ( Alpha System and ProTaper Universal ) in comparison to stainless steel h and instruments . METHODOLOGY A total of 45 mesial root canals of extracted human m and ibular molars were selected . On the basis of the degree of curvature the matched teeth were allocated r and omly into three groups of 15 teeth each . In group 1 root canals were prepared to size 30 using a st and ardized manual preparation technique ; in group 2 and 3 rotary NiTi instruments were used following the manufacturers ' instructions . Instrumentation time and procedural errors were recorded . With the aid of pre- and postoperative radiographs , apical straightening of the canal curvature was determined . Photographs of the coronal , middle and apical cross-sections of the pre- and postoperative canals were taken , and superimposed using a st and ard software . Based on these composite images the portion of uninstrumented canal walls was evaluated . RESULTS Active instrumentation time of the  Alpha System  was significantly reduced compared with ProTaper Universal and h and instrumentation ( P < 0.05 ; anova ) . No instrument fractures occurred in any of the groups . The Alpha System revealed significantly less apical straightening compared with the other instruments ( P < 0.05 ; Mann-Whitney U test ) . In the apical cross-sections Alpha System result ed in significantly less uninstrumented canal walls compared with stainless steel files ( P < 0.05 ; chi-squared test ) . CONCLUSION Despite the demonstrated differences between the systems , an apical straightening effect could not be prevented ; areas of uninstrumented root canal wall were left in all regions using the various systems AIM To assess the microflora of root canals in primary molars following use of rotary NiTi files and conventional h and NiTi and stainless steel files . STUDY DESIGN This r and omized clinical trial consisted of a total of 60 first and second primary molars requiring root canal treatment , who were selected from children aged 5 - 9 years . Based on type of root canal instrumentation , the teeth were r and omly assigned to three groups of twenty teeth each ; Group A : Rotary NiTi files , Group B : H and NiTi files and Group C : H and stainless steel files . Following administration of local anesthesia , isolation with rubber dam was carried out . For the purpose of instrumentation and sampling , the palatal canal of maxillary molars and the distal canal of m and ibular molars were selected . Prior to sampling , the orifices of other canals in these teeth were sealed , so as to prevent any contamination . Instrumentation was carried out in each group using respective instruments along with intermittent saline irrigation . Root canal sample s were obtained both before and after instrumentation , using sterile absorbent paper points and transferred to a sterile vial with transport fluid . Serial dilutions were prepared and cultured on suitable agar media . Both aerobic and anaerobic microbial counts were made . Data obtained was subjected to statistical analysis using Wilcoxon signed rank test and one-way Analysis of variance . RESULTS In all three groups , there was a significant reduction in both aerobic and anaerobic mean microbial count following root canal instrumentation . ( p < 0.001 ) . CONCLUSION Rotary NiTi files were as efficient as conventional h and instruments in significantly reducing the root canal microflora INTRODUCTION Nickel-titanium rotary instruments reduce procedural errors and the time required to finish root canal preparation . The goal of this study was to evaluate the occurrences of apical transportation and canal aberrations produced with different instruments used to create a glide path in the preparation of curved root canals , namely manual K-files ( Dentsply Maillefer , Ballaigues , Switzerl and ) and PathFile ( Dentsply Maillefer ) and Mtwo ( Sweden and Martina , Padua , Italy ) nickel-titanium rotary files . METHODS The mesial canals of 45 m and ibular first and second molars ( with curvature angles between 25 ° and 35 ° ) were selected for this study . The specimens were divided r and omly into 3 groups with 15 canals each , and canal preparation was performed by an endodontist using # 10 - 15 - 20 K-type stainless steel manual files ( group M ) , # 13 - 16 - 19 PathFile rotary instruments ( group PF ) , and # 10 - 15 - 20 Mtwo rotary instruments ( group MT ) . The double digital radiograph technique was used , pre- and postinstrumentation , to assess whether apical transportation and /or aberration in root canal morphology occurred . The initial and final images of the central axis of the canals were compared by superimposition through computerized analysis and with the aid of magnification . The specimens were analyzed by 3 evaluators , whose calibration was checked using the Kendall agreement test . RESULTS No apical transportation or aberration in root canal morphology occurred in any of the teeth ; therefore , no statistical analysis was conducted . CONCLUSIONS Neither the manual instruments nor the PathFile or Mtwo rotary instruments used to create a glide path had any influence on the occurrence of apical transportation or produced any canal aberration This study compared preparations of curved canals , using Profile , GT file and Hero 642 rotary files .  A total of 30 mesiobuccal canals of extracted first and second m and ibular molars were used in this study . The teeth were embedded in resin and a pre-operative radiograph was taken . The specimens were then r and omly divided into three instrument groups . Pre- and post-instrumentation radiographic images were scanned and superimposed using the VISI CAD/CAM program . At nine horizontal sections at 1 mm increments from the apex , it calculated pre- and post-instrumentation cross sectional areas ( mm(2 ) ) and enlargements to the inner aspect and outer aspects ( mm ) . A Kruskal-Wallis test found no statistical difference among the groups in terms of total areas removed by each instrument ( P > 0.05 ) . It also found no significant difference in any group between the total of the inner and outer enlargements ( P > 0.05 ) . However the GT file removed significantly more material from the outer side of the canal than the inside at sections 3 - 5 , and the Hero removed significantly more material from the outer side at sections 7 - 9 ( P < 0.05 ) . All instruments produced preparations that maintained original canal curvatures INTRODUCTION This study evaluated the prepared surface areas of oval-shaped canals in distal roots of m and ibular molars using four different instrumentation techniques . METHODS Teeth were prescanned and reconstructed using micro-computed tomography ( MCT ) scans at low resolution ( 68 microm ) . Forty-eight molars with ribbon-shaped/oval distal root canals were selected and r and omly assigned to four groups . Distal canals ( n = 12 each ) were prepared by circumferential filing using Hedström files to apical size # 40 ( group H/CF ) ; with ProTaper nickel-titanium rotaries to finishing file 4 ( F4 ) considering the distal canal as 1 canal ( group PT/1 ) ; ProTaper to F4 considering buccal and oral aspects of the distal canal as 2 individual canals ( group PT/2 ) ; ProTaper to F4 in a circumferential filing motion ( PT/CF ) . Before and after shaping , teeth were evaluated using MCT at 34-microm resolution . The percentage of prepared surface was assessed for the full canal length and the apical 4 mm . Statistical analysis was performed using analysis of variance and Bonferroni/Dunn multiple comparisons . RESULTS Preoperatively , canal anatomy was statistically similar among the groups ( p = 0.56 ) . Mean ( + /- st and ard deviation ) untreated areas ranged from 59.6 % ( + /-14.9 , group PT/2 ) to 79.9 % ( + /-10.3 , PT/1 ) for the total canal length and 65.2 % to 74.7 % for the apical canal portion , respectively . Canals in group PT/1 had greater untreated surface areas ( p < 0.01 ) than groups PT/2 and PT/CF . Among all groups , amounts of treated surface areas were statistically similar in the apical 4 mm . CONCLUSIONS Preparations of oval-shaped root canals in m and ibular molars left a variable portion of surface area unprepared regardless of the instrumentation technique used . However , considering oval canals as two separate entities during preparation appeared to be beneficial in increasing overall prepared surface BACKGROUND The purpose of this in-vitro study was to compare canal transportation and centering ability of Twisted and Hyflex Rotary Files with stainless steel h and k-flexofiles by using Spiral Computed Tomography . MATERIAL S & METHODS A total of 90 freshly extracted human m and ibular single rooted Premolar teeth were selected . The crowns were flattened with steel disks and a final dimension of 18-mm WL was achieved for each tooth . Canals were divided r and omly into 3 groups of 30 teeth each . Group I : Hyflex files , Group II : Twisted files , Group III : stainless steel h and k-flexofiles . Three sections from apical , mid-root , and coronal levels of the canal were recorded . All the teeth were scanned before and after instrumentation by using Spiral Computed Tomography . RESULTS K-files showed highest transportation and less centered when compared to the Twisted and Hyflex rotary files . No significant difference was found between TF and Hyflex CM instruments . CONCLUSION TF and Hyflex files shaped curved root canals without significant shaping errors when compared to the H and stainless steel k-flexofiles . How to cite this article : Kumar BS , Pattanshetty S , Prasad M , Soni S , Pattanshetty KS , Prasad S. An in-vitro Evaluation of canal transportation and centering ability of two rotary Nickel Titanium systems ( Twisted Files and Hyflex files ) with conventional stainless Steel h and K-flexofiles by using Spiral Computed Tomography . J Int Oral Health 2013;5(5):108 - 15 INTRODUCTION The purpose of this study was to compare canal transportation and centering ability of 2 rotary nickel-titanium ( NiTi ) systems ( Twisted Files [ TF ] and Pathfile-ProTaper [ PP ] ) with conventional stainless steel K-files . METHODS Ninety root canals with severe curvature and short radius were selected . Canals were divided r and omly into 3 groups of 30 each . After preparation with TF , PP , and stainless steel files , the amount of transportation that occurred was assessed by using computed tomography . Three sections from apical , mid-root , and coronal levels of the canal were recorded . Amount of transportation and centering ability were assessed . The 3 groups were statistically compared with analysis of variance and Tukey honestly significant difference test . RESULTS Less transportation and better centering ability occurred with TF rotary instruments ( P < .0001 ) . K-files showed the highest transportation followed by PP system . PP system showed significant transportation when compared with TF ( P < .0001 ) . CONCLUSIONS The TF system was found to be the best for all variables measured in this study The purpose of this study was to compare intracanal bacterial reduction on teeth instrumented with 0.04 tapered nickel-titanium ( NiTi ) rotary instrumentation to bacterial reduction when using a stainless-steel K-file step-back technique using sterile saline irrigation .  Forty-eight patients with apical periodontitis were r and omly assigned treatment type . The canals were sample d before , during , and after instrumentation . The sample s were incubated anaerobically for 7 days at 37 degrees C , colony-forming unit numbers calculated , and a log transformation performed to normalize the counts . Teeth exhibiting apical periodontitis were uniformly infected , whereas vital control teeth were not . A similar and uniform reduction occurred with progressive filing , regardless of technique ( p < 0.0001 ) . There was no detectable difference in colony-forming unit count after NiTi rotary or stainless-steel h and instrumentation ( p = 0.42 ) . Neither technique could predictably render canals free of bacteria . The results of this study indicate NiTi rotary and stainless-steel h and K-file step-back instrumentation techniques were not significantly different in their ability to reduce intracanal bacteria AIM To compare in vitro intracanal bacterial reduction using nickel-titanium rotary instruments with and without apical enlargement . METHODOLOGY Thirty-eight palatal roots of maxillary molar teeth , with mature apices were subdivided according to lengths and then r and omly assigned to two experimental and one control groups . The roots were sterilized and then reinfected with Enterococcus faecalis , which served as a bacteriological marker . All roots in the experimental groups were prepared in a step-down sequence with engine-driven GT rotary files at 350 rpm . In experimental group A ( n = 16 ) additional apical enlargement to ISO size 35 was performed . In group B ( n = 16 ) a serial step-back technique was followed with no apical enlargement . This was combined in groups A and B with irrigation with NaOCl and EDTA . In the control group ( group C , n = 6 ) irrigation only was carried out , with no mechanical preparation . Sample s were then taken from the root canals to determine the numbers of remaining bacteria . RESULTS In groups A and B , 15 ( 94 % ) and 13 ( 81 % ) specimens were rendered bacteria-free , respectively . In the control group C none of the specimens were bacteria-free . There was a significant difference ( P < 0.001 ) in the antibacterial effects of experimental and control regimens . There was , however , no significant difference ( P = 0.276 ) between the preparation methods used in the experimental groups . CONCLUSIONS There was no significant difference in intracanal bacterial reduction when Ni-Ti GT rotary preparation with NaOCl and EDTA irrigation was used with or without apical enlargement preparation technique . It may therefore not be necessary to remove dentine in the apical part of the root canal when a suitable coronal taper is achieved to allow satisfactory irrigation of the root canal system with antimicrobial agents AIM To prospect ively determine the incidence of nickel-titanium rotary instrument fracture in an endodontic clinical practice setting . METHODOLOGY Eleven second year endodontic residents , using four nickel-titanium rotary instrument systems ( ProFile , ProTaper , GTRotary and K3Endo )  according to the recommendations of the manufacturers , instrumented 3181 canals in 1403 teeth of 1235 patients , in a dental school post-graduate endodontic clinic , in 1 year . The incidence of instrument fracture was determined based on the number of instruments used . When fracture occurred , data were collected concerning the type , size , taper and prior use of the fractured instruments , the length and location of the fragment within the root canal and the curvature of the canal . RESULTS The overall incidence of instrument fracture was 0.39 % . The incidence of fracture for ProFile , ProTaper , GTRotary and K3Endo files was 0.28 % , 0.41 % , 0.39 % and 0.52 % , respectively . There was no statistically significant difference between instrument systems . The percentage of teeth in which instruments fractured was 1.9 % ( 0.28 % for anterior teeth , 1.56 % for pre-molars and 2.74 % for molars ) . A total of 26 instruments fractured , of which 23 had tapers of 0.06 or greater . Most of the fragments were located in the apical third of the root canal , and both the median and mode amongst the fragment lengths were 2 mm . CONCLUSIONS The low incidence of nickel-titanium rotary instrument fracture supports the continued use of these instruments in root canal treatment Background : Root canal cleaning is an important step in endodontic therapy . In order to develop better techniques , a new generation of endodontic instruments has been design ed . The aim of this study was to compare the effectiveness of manual K-files ( Mani Co , Tokyo , Japan ) and two rotary systems – Mtwo ( Dentsply-Maillefer , Ballaigues , Switzerl and ) and ProTaper ( VDW , Munich , Germany)–for root canal preparation in primary molars . Material s and Methods : India ink was injected to 160 mesiobuccal and distal root canals of m and ibular primary molars . The teeth were r and omly divided into three experimental groups and one control group . In each experimental group , either manual instruments ( K-files ) or rotary instruments ( Mtwo or ProTaper ) were used to prepare root canals . After cleaning the canals and clearing the teeth , ink removal was evaluated with a stereomicroscope . Statistical analysis was done with Kruskal – Wallis and Friedman tests . Results : There were no significant differences in cleaning efficiency between manual and rotary instruments . Only ProTaper files performed significantly better in the coronal and middle thirds than in the apical third of the root canal . Conclusion : Manual K-files and the Mtwo and ProTaper rotary systems showed equally acceptable cleaning ability in primary molar root canals AIM To compare the cleaning ability and preparation time of rotary instruments ( Mtwo ) and conventional manual instruments ( K-file ) in preparing primary and permanent molar root canals . MATERIAL S AND METHODS Access cavities were prepared in 70 primary and 70 permanent teeth and  India ink was injected into 120 canals of selected molars . The teeth were r and omly divided into two main subgroups ( n=20 ) and three control groups ( n=10 ) . In each of these main subgroups , either the manual instrument ( K-file ) or the rotary system ( Mtwo ) was used to prepare root canals . After cleaning the canals and clearing the teeth , dye removal was evaluated with the help of a stereomicroscope . In addition , the time needed for root canal preparation was recorded by a chronometer . STATISTICAL ANALYSIS Statistical analyses were done using the Kruskal-Wallis , Mann-Whitney and t tests . RESULTS With regard to the cleaning ability of root canals , there were no significant differences between the K-file and Mtwo rotary system in primary and permanent teeth in the apical , middle or coronal third of the canals . Moreover , there were no significant differences between primary and permanent teeth prepared with K-files and rotary instruments . In all the groups , shorter times were recorded with the rotary technique . The working time was shorter in primary than in permanent teeth . CONCLUSION The Mtwo rotary system showed acceptable cleaning ability in both primary and permanent teeth , and achieved results similar to those of K-files in less time AIM The aim of this study was to assess the clinical perfomance of a cordless h and piece with a built-in apex locator - the Tri Auto ZX - design ed for root canal preparation with nickel-titanium rotary files . METHODOLOGY Twenty-five human maxillary incisor and canine teeth scheduled for extraction with mature apices were selected for the study . Informed written consent was obtained from each patient before treatment . After administration of local anaesthesia , the teeth were isolated and the pulp cavities accessed . The Tri Auto ZX along with a size 15 K-file was used in its electronic apex locating function based on the manufacturer 's recommendations . A periapical radiograph with the file at the electronically determined constriction was taken , the file removed and the measurement registered as the electronic length ( EL ) . To test the auto reverse function , a size 20 ProFile.04 taper NiTi rotary instrument was mounted in the h and piece . The point for the auto apical reverse function was preset on the panel at the 0.5 mm level . After the file was introduced into the canal and reached the predetermined level , the file automatically stopped and rotated in the opposite direction . A reference point was marked and this measurement was registered as the auto reverse length ( ARL ) . All measurements were made twice by two different investigators . Teeth were then extracted and immersed in a 20 % formalin solution for 48 h. After fixation , a size 15 file was inserted into the canal to measure the actual root canal length from the same reference point obtained with the Tri Auto ZX to the apical foramen , as seen in the stereo microscope . When the file tip was visible at the anatomical end of the canal it was withdrawn 0.5 mm and this measurement was registered as the actual length ( AL ) . All measurements were expressed in mm and the measuring accuracy was set to 0.5 mm . The significance of the mean differences between EL and ARL and between EL and AL measurements at the 5 % confidence level was evaluated . RESULTS EL measurements were coincident to ARL in all instances . EL and ARL were coincident to AL in 10 ( 40 % ) canals , in the remaining 15 canals ( 60 % ) the AL measurements were longer than EL and ARL ( + 0.5 mm ) in 14 instances and shorter ( -0.5 mm ) in one case . Overall , the AL was longer than the EL or ARL , the mean difference being -0.23 mm + /- 0.32 ( P < 0.05 ) . CONCLUSIONS It was concluded that the Tri Auto ZX was useful and reliable . The Tri Auto ZX measurements protected against overpreparation Background . Efficient canal preparation is the key to successful root canal treatment . This study aim ed to assess the cleaning and shaping ability , preparation time and file deformation of rotary , reciprocating and manual instrumentation in canal preparation of primary molars . Methods . The mesiobuccal canals of 64 extracted primary m and ibular second molars were injected with India ink . The sample s were r and omly divided into one control and three experimental groups . Experimental groups were instrumented with K-file , Mtwo in continuous rotation and Reciproc in reciprocating motion , respectively . The control group received no treatment . The files were discarded after four applications . Shaping ability was evaluated using CBCT . After clearing , ink removal was scored . Preparation time and file fracture or deformation was also recorded . Data were analyzed with SPSS 19 using chi-squared , Fisher ’s exact test , Kruskal-Wallis and post hoc tests at a significance level of 0.05 . Results . Considering cleanliness , at coronal third Reciproc was better than K-file ( P < 0.001 ) , but not more effective than Mtwo ( P = 0.080 ) . Furthermore , Mtwo leaved the canal cleaner than K-file ( P = 0.001 ) . In the middle third , only Reciproc exhibited better cleaning efficacy than K-file ( P = 0.005 ) . In the apical third , no difference was detected between the groups ( P = 0.794 ) . Regarding shaping ability , no differences were found between Reciproc and Mtwo ( P = 1.00 ) . Meanwhile , both displayed better shaping efficacy than K-file ( P < 0.05 ) . Between each two groups , there were differences in preparation time ( P < 0.05 ) , with Reciproc being the fastest . No file failure occurred . Conclusion . Fast and sufficient cleaning and shaping could be achieved with Mtwo and especially with Reciproc Introduction : One of the most important reasons for postoperative pain is the extrusion of debris from the apical foramen during preparation and shaping of root canals . The aim of this clinical trial was to evaluate the severity of postoperative pain with the use of two different engine-driven NiTi systems . Methods and Material s : Ninety m and ibular molars were r and omly divided into two groups ( n=45 ) , and root canal cleaning and shaping was done using either RaCe or Reciproc instruments . The severity of postoperative pain was determined with visual analogue scale ( VAS ) at 4- , 12- , 24- , 48- and 72 h and 1-week intervals and postoperative pain was compared between the two groups . The chi-squared test and repeated- measures analysis were used to compare the data between the two groups . Results : Based on the results of the statistical analyses , the two groups were matched regarding the age and gender , with no significant differences . In addition , except for 4- and 24-h and 1-week intervals , postoperative pain was significantly less in the RaCe group compared to the Reciproc group ( P<0.001 ) . Conclusion : Based on the results of the present study , use of RaCe files for cleaning and shaping of root canals in necrotic m and ibular molars result ed in less severe postoperative pain compared to Reciproc files INTRODUCTION : Pulpectomy of primary teeth is commonly carried out with h and files and broaches ; a tricky and time consuming procedure . The purpose of this in vitro study was to compare the cleaning efficacy and time taken for instrumentation of deciduous molars using h and K-files and Flex Master rotary system . MATERIAL S AND METHODS : In this study , 68 canals of 23 extracted primary molars with at least two third intact roots and 7 - 12 mm length were selected . After preparing an access cavity , K-file size # 15 was introduced into the root canal and India ink was injected with an insulin syringe . Sixty sample s were r and omly divided in to experimental groups in group I ( n=30 ) , root canals were prepared with h and K-files ; in group II ( n=30 ) , rotary Flex Master files were used for instrumentation , and in group III 8 remained sample s were considered as negative controls . After clearing and root sectioning , the removal of India ink from cervical , middle , and apical thirds was scored . Data was analyzed using student 's T-test and Mann-Whitney U test . RESULTS : There was no significant difference between experimental groups cleaning efficacy at the cervical , middle and apical root canal thirds . Only the coronal third scored higher in the h and instrumented group ( P<0.001 ) . Instrumentation with Flex Master rotary files was significantly less time consuming ( P<0.001 ) . CONCLUSION : Although there was no difference in cleanliness efficacy at the apical and middle thirds , the coronal third was more effectively cleaned with h and files . Predictably , time efficiency was a significant advantage with rotary technique INTRODUCTION This study sought to present a st and ardized biofilm model in extracted teeth with an artificial apical groove to quantify the efficacy of h and , rotary nickel-titanium , and self-adjusting file ( SAF ) instrumentation in biofilm bacteria removal . METHODS Thirty-six extracted single-rooted teeth with oblong canals were selected . Each tooth was split longitudinally , and a 0.2-mm-wide groove was placed in the apical 2 to 5 mm of the canal . After growing mixed bacteria biofilm inside the canal under an anaerobic condition , the split halves were reassembled in a custom block , creating an apical vapor lock . Teeth were r and omly divided into 3 treatment groups ( n = 10 per group ) using the K-file , ProFile ( Dentsply Tulsa Dental Products , Tulsa , OK ) , and the SAF ( ReDent-Nova , Ra'anana , Israel ) . Irrigation consisted of 10 mL 3 % NaOCl and 4 mL 17 % EDTA .  Six teeth received no treatment . Areas inside and outside the groove were examined using a scanning electron microscope . RESULTS The scanning electron microscope showed a consistently thick layer of biofilm grown in the canals of the control group after 4 weeks . Within the groove , a smaller area remained occupied by bacteria after the use of the SAF compared with the ProFile and the K-file ( 3.25 % , 19.25 % , and 26.98 % , respectively ; P < .05 ) . For all groups , significantly more bacteria were removed outside the groove than inside ( P < .05 ) . No statistical differences were found outside the groove ( P > .05 ) . CONCLUSIONS Although all techniques equally removed bacteria outside the groove , the SAF reduced significantly more bacteria within the apical groove . No technique was able to remove all bacteria . This biofilm model represents a potentially useful tool for the future study of root canal disinfection OBJECTIVE The aim of this r and omized clinical trial was to evaluate the frequency of bacteriemia during endodontic treatment , with comparison between two techniques for biomechanical preparation of the root canal system . MATERIAL S AND METHODS The sample comprised 50 patients aged 16 to 52 years , of both genders , which were divided into 2 groups with 25 patients each . Group I underwent biomechanical preparation by the step-back technique , and Group II was treated by the rotary technique with nickel-titanium instruments ( K3 ) . Patients were su bmi tted to antisepsis of the oral cavity with chlorhexidine digluconate and three sample s of blood were collected for blood culture : preoperatively , immediately after the biomechanical preparation and 10 minutes later . The significance level adopted was 5.0 % , and analysis was performed by descriptive and inferential statistics by means of the Fisher 's exact test , Fisher-Freeman-Halton test and Student 's t test . Data were analyzed on the Statexact and SPSS softwares . RESULTS All blood cultures achieved before and immediately after preparation were negative . On the other h and , with regard to the blood cultures collected 10 minutes after preparation , one ( 4 % ) positive case was found for Group I. However , this difference was not statistically significant ( p = 0.50 ) . CONCLUSION The frequency of bacteriemia was low and observed just for Group
Therefore , the rotary NiTi Hero 642 and K3 files demonstrated comparable shaping abilities and maintenance of working length
The aim of the present study was to compare the root canal preparation ability of rotary nickel-titanium ( NiTi ) Hero 642 and K3 files in curved m and ibular or maxillary molars .