Influence of the NiTi rotary system on the debridement quality of the root canal space. Ex vivo study on root canal instrumentation of two rotary nickel-titanium systems in comparison to stainless steel hand instruments. Comparison of curved canals preparations using profile, GT and Hero 642 rotary files. 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. A comparison of Profile, Hero 642, and K3 instrumentation systems in teeth using digital imaging analysis. Effect of three nickel-titanium rotary file techniques on infected root dentin reduction. Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. Bacterial reduction with nickel-titanium rotary instrumentation. A retrospective study of endodontic treatment outcome between nickel-titanium rotary and stainless steel hand filing techniques. 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 Comparison among manual instruments and PathFile and Mtwo rotary instruments to create a glide path in the root canal preparation of curved canals. Microbiological assessment of root canals following use of rotary and manual instruments in primary molars. 'Volumetric analysis of hand and rotary root canal instrumentation and filling in primary teeth using Spiral Computed Tomography' - an invitro study. Nickel-titanium rotary instrument fracture: a clinical practice assessment. Rotary Mtwo system versus manual K-file instruments: efficacy in preparing primary and permanent molar root canals. Clinical study of single-visit root canal treatment with a nickel-titanium (Ni-Ti) rotary instrument combined with different ultrasonic irrigation solutions for elderly patients with chronic apical periodontitis. Improved quality of root fillings provided by general dental practitioners educated in nickel-titanium rotary instrumentation.
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 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 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 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 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 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 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 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 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 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 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 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 AIM To compare and evaluate the volumetric analysis of pre- and post-root canal instrumentation in primary teeth using h and and rotary files and also to analyse the volume of root canal filling . MATERIAL S AND METHODS A total of 20 primary teeth were divided into two groups r and omly and subjected to spiral computed tomography ( SCT ) analysis before and after instrumentation . For manual technique ( Group 1 ) , teeth were prepared using K files and rotary ( Group 2 ) preparation was performed with Mtwo files .  Volumetric enlargement was calculated using Osirix software . Root canals were then filled with rotary lentulospiral using zinc oxide-eugenol cement ( ZOE ) . The filled volume in each canal was measured using SCT and the percentage of obturated volume was calculated . The data were statistically analysed using paired t-tests . RESULTS There was a statistically significant difference in the volume of root canal enlarged in both the groups . Rotary files showed significant increase in the volume compared to K files . Mtwo instrumented root canals showed good obturated volume compared to manual technique , although voids were common in both the groups . CONCLUSION Rotary root canal instrumentation may be indicated for utilization in primary teeth , for enhancing root canal preparation and good quality of root canal filling 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 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 The study involved 300 elderly patients with chronic periapical periodontitis . The patients were r and omly assigned into three groups . The treatment for group A used a Mtwo Ni-Ti rotary instrument combined with ultrasonic irrigation of a 2.5 % NaOCl solution . The group B used the same instrument combined with ultrasonic irrigation of an active silver ion antibacterial solution . The group C used the same instrument combined with syringe irrigation of a 2.5 % NaOCl solution . The root canal fillings were performed immediately after canal preparation . Twenty-four hours after the procedure , patients self-assessed pain levels according to the VAS table . The three groups returned after seven days so their postoperative acute reactions could be evaluated clinical ly . After six and twelve months , efficacy was evaluated . The self-assessed pain levels for group A and B were significantly lower than group C. The incidence of postoperative acute reactions after seven days for group A and B were significantly lower than those of group C. The effective rates after six and twelve months did not differ among these groups . The single-visit root canal treatment with a nickel-titanium rotary instrument combined with ultrasonic irrigation for elderly patients with chronic periapical periodontitis achieved short and long term efficacy and stability AIM To test the hypothesis that an increased utilization of nickel-titanium rotary instrumentation ( NTRI ) by general dental practitioners will lead to an increased frequency of good quality root fillings . A second aim was to determine whether the educational format would exert influence on the quality . METHODOLOGY Dentists were assigned at r and om to three intervention groups : a 4-h lecture  ( L-group , n = 40 ) ; a 4-h lecture plus a full day h and s-on course  ( LH-group , n = 40 ) ; or a control group receiving no instruction ( n = 68 ) . The control group received education later on in the study . Radiographs of two root filled molar teeth per dentist were selected at r and om before the start of the education program and after a 6-month clinical learning period . Using length , seal and shape of root-fillings a 5-level variable was created . RESULTS The rate of good quality root fillings increased after the introduction of NTRI . Calculated over all types of roots the frequency of excellent ( score 1 ) root fillings increased from 31 % to 51 % ( P = 0.006 ) in the L-group and from 27 % to 47 % ( P = 0.016 ) in the LH-group . The frequency of low quality root-fillings ( score 5 ) dropped in the L-group from 22 % to 16 % ( P = 0.29 ) and in the LH-group from 13 % to 9 % ( P = 0.48 ) . No statistically significant difference was seen among the controls . CONCLUSIONS When NTRI technology replaced manual stainless steel techniques the rate of good quality root fillings increased . A significant drop in the rate of low quality root fillings was not found
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 .