Bacterial reduction with nickel-titanium rotary instrumentation. Effect of three nickel-titanium rotary file techniques on infected root dentin reduction. Comparison of canal transportation and centering ability of twisted files, Pathfile-ProTaper system, and stainless steel hand K-files by using computed tomography. A retrospective study of endodontic treatment outcome between nickel-titanium rotary and stainless steel hand filing techniques. 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. Ex vivo study on root canal instrumentation of two rotary nickel-titanium systems in comparison to stainless steel hand instruments. 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. Ability of chemomechanical preparation with either rotary instruments or self-adjusting file to disinfect oval-shaped root canals. Clinical evaluation of dental alignment and leveling with three different types of orthodontic wires. A comparative study of biofilm removal with hand, rotary nickel-titanium, and self-adjusting file instrumentation using a novel in vitro biofilm model. Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. In vivo determination of root canal length: a preliminary report using the Tri Auto ZX apex-locating handpiece. Nickel-titanium rotary instrument fracture: a clinical practice assessment. A randomized clinical trial investigating pain associated with superelastic nickel–titanium and multistranded stainless steel archwires during the initial leveling and aligning phase of orthodontic treatment Clinical comparison and performance perspective of three aligning arch wires. The timing of significant arch dimensional changes with fixed orthodontic appliances: data from a multicenter randomised controlled trial. Improved quality of root fillings provided by general dental practitioners educated in nickel-titanium rotary instrumentation. Smear Layer Evaluation on Root Canal Preparation with Manual and Rotary Techniques using EDTA as an Irrigant: A Scanning Electron Microscopy Study. Multiflex versus superelastic: a randomized clinical trial of the tooth alignment ability of initial arch wires. Which orthodontic archwire sequence? A randomized clinical trial.
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 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 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 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 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 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 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 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 INTRODUCTION A wide variety of orthodontic wires made of different alloys is available to be used in orthodontic practice and may produce different clinical responses during tooth movement . OBJECTIVE This research evaluated the alignment and leveling of lower dental arches after the use of three types of orthodontic wires . METHODS A sample of 36 patients was r and omly divided into 3 groups : stainless steel , multistr and ed steel and superelastic nickel-titanium , according to the first leveling arches used . In order to observe differences in tooth position and axial inclination of the lower incisors , all patients had lateral cephalometric radiographs taken before the insertion of the first arches and 2 months later . The irregularity index and the curve of Spee were measured , compared between groups and considered influential on the proclination of incisors during the initial phase of alignment and leveling . The Reflex microscope was used to measure the irregularity index , whereas the ANOVA analysis of variance was used to verify differences between groups with regard to the degree of dental alignment and leveling . RESULTS There were significant differences between groups only at T2 for the irregularity index . CONCLUSIONS The NiTi and multistr and ed steel wires showed greater aligning capacity when compared with stainless steel wires 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 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 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 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 Objective To investigate and compare the effects of superelastic nickel – titanium and multistr and ed stainless steel archwires on pain during the initial phase of orthodontic treatment . Design A double-blind two-arm parallel design stratified r and omized clinical trial . Setting A single centre in India between December 2010 and June 2012 . A total of 96 participants ( 48 male and 48 females ; 14.1±2.1 years old ) were r and omized ( stratified on age , sex and initial crowding ) to superelastic nickel – titanium or multistr and ed stainless steel archwire groups using a computer-generated allocation sequence . Methods We compared 0.016-inch superelastic nickel – titanium and 0.0175-inch multistr and ed stainless steel wires in 0.022-inch slot ( Roth prescription ) preadjusted edgewise appliances . The follow-up period was 14 days . Outcome was assessed with a visual analogue scale at baseline and 32 pre-specified follow-up points . Data was analyzed using mixed-effects model analysis . Results One participant was lost to follow up and 10 were excluded from the analysis due to bond failure or incomplete question naire answers . Ultimately , 85 participants ( 42 males and 43 females ; 14.1±2.0 years old ) were analysed for the final results . No statistically significant difference was found for overall pain [ F value = 2.65 , degrees of freedom ( df ) = 92.6 ; P = 0.1071 ] . However , compared to multistr and ed stainless steel wires , pain in subjects with superelastic nickel – titanium archwires was significantly greater at 12 h ( t = 2.34 ; P = 0.0193 ) , as well as at day 1 in the morning ( t = 2.21 , P = 0.0273 ) , afternoon ( t = 2.11 , P = 0.0346 ) and at bedtime ( t = 2.03 , P = 0.042 ) . Conclusion For overall pain , there was no statistically significant difference between the two wires . However , subjects with superelastic nickel – titanium archwires had a significantly higher pain at peak level OBJECTIVES To clinical ly evaluate three commonly used orthodontic tooth aligning arch wires : 016 x 022 inch active martensitic medium force nickel titanium , 016 x 022 inch grade d force active martensitic nickel titanium , and 0.0155 inch multistr and stainless steel . DESIGN A prospect i ve r and omized clinical trial . DATA SOURCE Measured serial study casts of dental arches for 112 assigned arch wires from 56 consecutive patients . Analysis based on completed records for 98 arch wires and 51 patients . METHOD A consecutive sample of 56 patients requiring both upper and lower fixed appliance therapy were r and omly allocated two different arch wires from a possible three under trial . Good quality impressions were taken of the dental arches at the design ated serial stages of alignment ( start , T0 ; 4 weeks , T4 ; 8 weeks , T8 ) . The result ant casts were measured on a Reflex Microscope to record the change in individual tooth alignment both in three and two dimensions ( horizontal plane only ) . RESULTS The measurement error was within acceptable limits ( range , 0.05 to 0.09 mm ) and showed no significant bias . ANOVA statistical models were fitted to the data to adjust for a number of variables . No significant difference in aligning capability ( p > 0.05 ) , in either two or three dimensions , was demonstrated between the three arch wires in the trial . CONCLUSION Heat activated nickel titanium arch wires failed to demonstrate a better performance than the cheaper multistr and stainless steel wires in this r and omized clinical trial . The failure to demonstrate in vivo superiority at the clinical level may be due to the confounding effects of large variations in individual metabolic response . Alternatively , it may be that in routine clinical practice NiTi-type wires are not sufficiently deformed to allow their full superelastic properties to come in to play during initial alignment OBJECTIVES To identify the timing of significant arch dimensional increases during orthodontic alignment involving round and rectangular nickel-titanium ( NiTi ) wires and rectangular stainless steel ( SS ) . A secondary aim was to compare the timing of changes occurring with conventional and self-ligating fixed appliance systems . METHODS In this non- primary publication , additional data from a multicenter r and omised trial initially involving 96 patients , aged 16 years and above , were analysed . The main pre-specified outcome measures were the magnitude and timing of maxillary intercanine , interpremolar , and intermolar dimensions . Each participant underwent alignment with a st and ard Damon ( Ormco , Orange , CA ) wire sequence for a minimum of 34 weeks . Blinding of clinicians and patients was not possible ; however , outcome assessors and data analysts were kept blind to the appliance type during data analysis . RESULTS Complete data were obtained from 71 subjects . Significant arch dimensional changes were observed relatively early in treatment . In particular , changes in maxillary inter-first and second premolar dimensions occurred after alignment with an 0.014 in . NiTi wire ( P<0.05 ) . No statistical differences in transverse dimensions were found between rectangular NiTi and working SS wires for each transverse dimension ( P>0.05 ) . Bracket type had no significant effect on the timing of the transverse dimensional changes . CONCLUSIONS Arch dimensional changes were found to occur relatively early in treatment , irrespective of the appliance type . Nickel-titanium wires may have a more profound effect on transverse dimensions than previously believed . CLINICAL SIGNIFICANCE On the basis of this research orthodontic expansion may occur relatively early in treatment . Nickel-titanium wires may have a more profound effect on transverse dimensions than previously believed 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 INTRODUCTION The aim of any root canal treatment is to achieve a canal free of micro organisms , residual pulp remnants , debris and smear layer for the long term success of the procedure . Manual and automated instrumentation techniques along with proper irrigation regime is used to arrive at the aforementioned goal . Many authors focused on the preparation capabilities of various manual and rotary instruments but very few investigators stressed on the actual cleaning abilities of these instruments . AIMS AND OBJECTIVES This study was undertaken to evaluate the cleaning efficiency of manual K flex files and rotary Pro File systems in the root canals using a scanning electron microscope . MATERIAL AND METHODS Thirty single rooted m and ibular first premolars were divided into two groups and r and omized ( the manual group-M and the ProFile group-P ) with respect to the preparation technique . The Manual group was h and instrumented with stainless steel K- Flexofiles by means of a conventional filing technique . The Pro File group was instrumented according to the manufacturer 's instructions using a rotary h and piece . All canals were shaped and cleaned under frequent irrigation with EDTA . Final irrigation was carried out with 3 mL of normal saline solution to neutralize the action of the irrigant . The roots were split , one half of each tooth was selected for further SEM technique analysis and examined under the scanning electron microscope . The canal walls were quantitatively evaluated for the amount of debris and smear layer . The apical , middle and coronal regions of the canal surface , were grade d ( 1 - 5 ) for debris and smear layer . A statistical analysis was performed using a Mann-Whitney Rank Sum test . ProFile performed least effective cleaning . Manual K-Flexofiles led to a grooved pattern . RESULTS AND CONCLUSION A statistically significant difference was observed ( p<0.05 ) between the two instrumentation techniques concerning the amount of debris and smear layer at the apical level . The manually filed canals had less debris and smear layer than those using a rotary technique . It was concluded from this study that none of the instrumentation techniques employed , produced the canal walls which were free of surface debris and smear layer . The manual instrumentation technique was better in cleaning the canals compared to the ProFile rotary Ni-Ti instruments despite the step-back technique used for manual instrumentation . How to cite this article : Manjunatha M , Kini A , Sudhakar V , Sunil K V C , Hiremath V K , Shah A. Smear Layer Evaluation on Root Canal Preparation with Manual and Rotary Techniques using EDTA as an Irrigant : A Scanning Electron Microscopy Study . J Int Oral Health 2013 ; 5(1):66 - 78 Two arch wires commonly used for initial tooth alignment were compared with regard to their clinical effectiveness . The two arch wires tested were 0.0155-inch diameter multiple-str and ed stainless steel wire ( Dentaflex , Dentaurium , Optident , Yorkshire , Engl and ) and 0.014-inch diameter nickel-titanium alloy wire ( NiTi , ORMCO Co. , Monrovia , Calif. ) . Consecutive patients attending an orthodontic clinic for routine placement of a fixed appliance were r and omly assigned one of these two initial arch wires . Good quality alginate impressions of the appropriate dental arch were taken before arch wire placement and also at the subsequent appointment , which was , on average , 6 weeks later . Seventy-four arches were used in this study . The degree of tooth alignment achieved for each wire type was compared with a Reflex Microscope ( Reflex Measurement Ltd. , Butleigh , Engl and ) to make detailed measurements on the result ant casts . The degree of initial alignment achieved with the two wires was similar over this 6-week period . However , some differences were found for the lower labial segment where the interbracket span is usually reduced and where the superelastic nickel-titanium wire was found to give improved alignment . No threshold of crowding was found where one arch wire performed better than the other The aim of this study was to compare three orthodontic archwire sequences . One hundred and fifty-four 10- to 17-year-old patients were treated in three centres and r and omly allocated to one of three groups : A = 0.016-inch nickel titanium ( NiTi ) , 0.018 x 0.025-inch NiTi , and 0.019 x 0.025-inch stainless steel ( SS ) ; B = 0.016-inch NiTi , 0.016-inch SS , 0.020-inch SS , and 0.019 x 0.025-inch SS ; and C = 0.016 x 0.022-inch copper ( Cu ) NiTi , 0.019 x 0.025-inch CuNiTi , and 0.019 x 0.025-inch SS . At each archwire change and for each arch , the patients completed discomfort scores on a seven-point Likert scale at 4 hours , 24 hours , 3 days , and 1 week . Time in days and the number of visits taken to reach a 0.019 x 0.025-inch SS working archwires were calculated . A periapical radiograph of the upper left central incisor was taken at the start of the treatment and after placement of the 0.019 x 0.025-inch SS wire so root resorption could be assessed . There were no statistically significant differences between archwire sequences A , B , or C for patient discomfort ( P > 0.05 ) or root resorption ( P = 0.58 ) . The number of visits required to reach the working archwire was greater for sequence B than for A ( P = 0.012 ) but this could not be explained by the increased number of archwires used in sequence
Conclusions The results of this systematic review suggested that NiTi rotary instruments were associated with lower canal transportation and apical extrusion when compared to SST h and files , whereas both groups had similar outcomes in terms of success of therapy , amount of residual bacteria , and cleansing ability after treatment .
Introduction This systematic review evaluated the effectiveness of  nickel‐titanium ( NiTi ) rotary files compared to stainless‐steel ( SST ) h and files .