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The effectiveness of root canal treatments with different file systems in primary teeth is important in terms of clinical practice and the use of file systems that work with different principles in primary tooth pulpectomy is becoming widespread. The amount of remaining dentin in the coronal region of the root is important in terms of the prognosis of the tooth and the long-term success of the treatment in teeth that have undergone root canal treatment. The aim of this study was to evaluate the remaining dentin volume in the coronal part of the root after the use of rotary, reciprocating, and conventional hand files in primary tooth pulpectomy. A total of 30 primary molars were divided into three groups. In each group, the preparations were made with three different file types: WaveOne Gold, which works with reciprocating motion; TruNatomy, which works with rotational motion; and conventional hand files. The three-dimensional images were evaluated for remaining dentin volume in the 2-mm coronal part of the root. Group means were compared using one-way analysis of variance, and post hoc analyses were performed with the Tukey test. There was no statistically significant difference between the groups in terms of preoperative and postoperative dentin volume (P > 0.05). The mean difference after preparation was observed the most in the WaveOne Gold group and the least in the TruNatomy group. When the mean percentage differences were evaluated, it was observed that statistically significantly more dentin volume was preserved after the preparation with TruNatomy than with WaveOne Gold (P = 0.021). In primary tooth pulpectomy, file systems working with rotational motion can be preferred over file systems working with reciprocating motion in preserving the amount of dentin in the 2-mm coronal part of the root. [ABSTRACT FROM AUTHOR]

Background/purpose: The effectiveness of root canal treatments with different file systems in primary teeth is important in terms of clinical practice and the use of file systems that work with different principles in primary tooth pulpectomy is becoming widespread. The amount of remaining dentin in the coronal region of the root is important in terms of the prognosis of the tooth and the long-term success of the treatment in teeth that have undergone root canal treatment. The aim of this study was to evaluate the remaining dentin volume in the coronal part of the root after the use of rotary, reciprocating, and conventional hand files in primary tooth pulpectomy. Materials and methods: A total of 30 primary molars were divided into three groups. In each group, the preparations were made with three different file types: WaveOne Gold, which works with reciprocating motion; TruNatomy, which works with rotational motion; and conventional hand files. The three-dimensional images were evaluated for remaining dentin volume in the 2-mm coronal part of the root. Group means were compared using one-way analysis of variance, and post hoc analyses were performed with the Tukey test. Results: There was no statistically significant difference between the groups in terms of preoperative and postoperative dentin volume (P > 0.05). The mean difference after preparation was observed the most in the WaveOne Gold group and the least in the TruNatomy group. When the mean percentage differences were evaluated, it was observed that statistically significantly more dentin volume was preserved after the preparation with TruNatomy than with WaveOne Gold (P = 0.021). Conclusion: In primary tooth pulpectomy, file systems working with rotational motion can be preferred over file systems working with reciprocating motion in preserving the amount of dentin in the 2-mm coronal part of the root.

Objective: This study aimed to examine the shaping ability of six rotary and reciprocating file systems, as well as hybrid techniques in simulated S-shaped root canals. Methods: A hundred and twenty S-shaped radiopaque thermosetting epoxy resin blocks were grouped according to the system used for biomechanical preparation. Six groups of 15 canals each were prepared using TruNatomy, Procodile, VDW Rotate, Hyflex CM, OneCurve, and WaveOne Gold, respectively. Two additional hybrid (Procodile/Hyflex CM and Procodile/TruNatomy) groups (n=15 each) were added after evaluating the results of individual systems. All canals were enlarged to 0.25 mm apically. Canal transportation, centering ability, diameter increase, and iatrogenic errors were assessed by superimposed pre-operative and post-operative images. AutoCAD was used for data analysis. All groups were statistically compared with analysis of variance and Tukey honest significant difference test (p<0.05). Results: Hyflex CM resulted in the most conservative diameter increase in all thirds (coronal, middle, and apical; p<0.001). Procodile showed the best (p<0.001) centering ability in the coronal and middle thirds, while TruNatomy resulted in the least canal transportation and most centering preparation in the apical third (p<0.001). Hybridisation of Procodile and Hyflex CM produced the least canal transportation and best centering ability in the middle third (p<0.001). No instrument breakage occurred, and no ledge, elbow, or apical zip formation was observed during canal preparation. Conclusion: Hybridisation of Procodile and Hyflex CM showed remarkable results in preserving the canal diameter in all thirds and resulted in the least canal transportation and best centering ability in the middle third of the canal. However, when treatment cost and duration limit the clinical applicability of the hybrid technique, clinicians can use a single file system (Hyflex CM or TruNatomy) since it shows satisfactory results in all parameters when compared with a hybrid system. [ABSTRACT FROM AUTHOR]

Introduction: Rotary nickel-titanium files for root canal therapy have become standard treatment modalities in general practice and specialized dental centers. Undergraduate dental students should receive proper training in using rotary files before graduation. Therefore, this study aimed to provide detailed insight into the implementation of rotary root canal instruments in the clinical training of undergraduate students in Saudi Arabia. Materials and Methods: Two randomly selected private schools and 13 government-owned schools were selected to represent all administrative regions in Saudi Arabia. The SurveyMonkey® questionnaire was sent to each dental school through direct communication. It covered most aspects of the rotary root canal instruments used in the clinical training of undergraduate students before graduation. Results: Approximately 92.9% of the included dental schools reported using rotary files in undergraduate teaching; however, only 57.1% had specific clinical requirements for rotary root canal instrumentation in their curricula. Laboratory simulation sessions were the most commonly used preclinical training methods for rotary instrumentation (85.7%). Most dental schools implemented rotary file training in the 4th and 5th years (53.8% and 38.5%, respectively). The ProTaper® (Universal, Next, Gold) was the most commonly used rotary system. Most dental schools had an instructor-to-student ratio of 1:5. Conclusion: Most Saudi dental schools have adopted rotary files during their undergraduate training. However, the curricula of some dental schools do not include a predetermined number of clinical cases treated with rotary instrumentation to ensure better training for students before graduation. [ABSTRACT FROM AUTHOR]

The use of file systems that work with different principles in root canal treatment is becoming widespread. The aim of this study was to evaluate the remaining dentine volume in the coronal region of the root and preparation efficiency after the use of conventional hand files, WaveOne Gold; which works with reciprocating motion, and TruNatomy; which works with rotational motion in the root canal treatment of mandibular molar teeth. All canals of permanent mandibular molars (n = 36) were used. Root canals in each group (n = 12) were prepared with conventional hand files, WaveOne Gold, and TruNatomy. The three-dimensional images were evaluated for remaining dentine volume in the coronal two-millimeter region of the root and change in volume of the entire root canal space. There was no statistically significant difference between the groups in terms of mean differences pre and postpreparation (P >.05). The mean differences after preparation were observed the most in the WaveOne Gold group and the least in the TruNatomy group in the coronal two-millimeter region of the root and entire canal volume, but the differences were not significant (P >.05, P >.05, respectively). Conventional hand files, WaveOne Gold working with reciprocating motion, and TruNatomy working with rotational motion, which are the file systems used in the study, are not superior to each other in terms of remaining dentin volume in the coronal two-millimeter region of the root and preparation efficiency in the entire root canal space in mandibular molars. [ABSTRACT FROM AUTHOR]

Clinicians should be aware of all the characteristics and capacities of the instruments that are possible to use when conducting a root canal treatment. The wide variety of nickel–titanium (Ni-Ti) rotary systems on the market and the lack of standardisation of this type of instrument makes the choice in each specific case difficult. Therefore, this review is intended to summarize the characteristics that should be taken into account when choosing one instrument over another. It will be essential to know characteristics, of alloy from which the instrument is made. Moreover, the geometry of the instrument will determine its behaviour, being the mass, the one that marks its resistance to a greater extent. The movement performed by the file is another of the fundamental keys to understand rotary instruments. In conclusion, when performing root canal treatment, the characteristics of the instrument and the tooth must be taken into account, and the operator's own limitations should be known. This paper provides the key points to keep in mind when making this type of treatment. [ABSTRACT FROM AUTHOR]

Introduction: To meet the demand of pediatric endodontists, exclusive pediatric rotary file systems have been recently introduced by the manufactures. However, no study has been conducted to compare the clinical efficiency between pediatric rotary file systems. Aim: To determine the clinical efficiency (instrumentation time, obturation time, quality of obturation and postoperative pain) of two pediatric rotary file systems following the root canal preparation of primary molars. Materials and Methods: A total of 75 primary molars requiring pulpectomy were selected from children aged 4 to 7 years. These teeth were divided into three groups of 25 teeth each. In the first, second, and third groups, the cleaning and shaping of the root canals were carried out with Pedo-Flex pediatric rotary files (Group PF), Kedo-S pediatric rotary files (Group KS), and, manual nickel-titanium K-files (Group MF), respectively. Obturation was carried out with zinc oxide eugenol cement with an engine-driven Lentulo spiral. The instrumentation and obturation times were recorded. The quality of the root filling was radiographically assessed immediately after obturation. The postoperative pain was evaluated at time intervals of 6, 12, 24, 48, 72 h, and 1 week. Results and Discussion: The instrumentation and obturation times were significantly less with the use of pediatric rotary file systems compared to the manual file system. The quality of obturation was superior in the root canals instrumented with pediatric rotary file systems compared to manual files. There was decreased postoperative pain with the use of pediatric rotary file systems as compared to manual files. In all three groups, postoperative pain decreased over time. The optimally filled root canals showed a significant correlation with the absence of postoperative pain. Conclusions: The use of pediatric rotary file systems for root canal instrumentation of primary molars resulted in the superior quality of obturation in decreased instrumentation and obturating times with the least postoperative pain. The overfilled root canals were not associated with significant postoperative pain. [ABSTRACT FROM AUTHOR]

Aim: To assess postoperative pain and bacterial reduction following the use of XP‐endo Shaper versus conventional rotary files in preparation of oval canals with necrotic pulps. Methodology: This superiority, parallel, randomized, double blinded clinical trial was conducted in the clinic of the Endodontic Department, Faculty of Dentistry, Cairo University, Egypt. Sixty single‐canalled mandibular premolars with necrotic pulps were randomly assigned into two equal groups. Canals were instrumented using XP‐endo Shaper files in the intervention group and iRaCe rotary files in the control group. Bacterial samples were taken before and after canal instrumentation. Incidence and severity of postoperative pain was assessed using a modified VAS after 6, 12, 24 h and daily for 5 days. A culture method was used to assess the number of bacterial colony forming units. Incidence of analgesic intake as well as flare‐ups was recorded. Data were analysed using chi‐square, Fisher Exact, Mann–Whitney, Independent t‐test, and Spearman's correlation for pain and bacterial counts. Results: The XP‐endo Shaper compared with the iRaCe group was associated with a significantly lower incidence of postoperative pain at 6, 12, and 24 h (P = 0.039, 0.047, and 0.026, respectively), and severity of postoperative pain at 6 h (mean difference: 1.33, 95% CI: 0.307–2.352, P = 0.02), 12 h (mean difference: 1.1, 95% CI: 0.26–1.936, P = 0.007), 24 h (mean difference: 0.94, 95% CI: 0.178–1.701, P = 0.008) and 48 h (mean difference: 0.97, 95% CI: 0.192–1.747, P = 0.038). There was a significant decrease in bacterial count following canal instrumentation in both groups (P < 0.001) with no significant difference between them (mean difference: 0.83 × 105, 95% CI: 0.336 × 105–1.996 × 105, P = 0.56). A weak correlation existed between postoperative pain severity and bacterial counts (P = 0.54). There was no significant difference in analgesic intake between the two groups (P = 0.085). Flare‐ups occurred in 3.3% of teeth in the iRaCe group, while no flare‐ups occurred in the XP‐endo Shaper group. Conclusions: XP‐endo Shaper was associated with a significantly lower frequency of postoperative pain for up to 24 h, and lower severity of postoperative pain for up to 48 h compared with iRaCe files. Both systems were equally effective in bacterial reduction from oval root canals with necrotic pulps. [ABSTRACT FROM AUTHOR]

Background. Pediatric endodontics is a field with constant evolution, resulting in the shifting of paradigms from the use of conventional hand files to rotary files for biomechanical preparation in primary teeth. Biomechanical preparation plays a crucial role in the success of root canal treatment. Primary teeth need special attention since they differ from permanent teeth in root canal morphology. Cleaning and shaping of the canals damage the root dentin, leading to dentinal cracks. Newer techniques for root canal preparation, including Ni-Ti rotary files and SAF system, have been developed for use in pediatric endodontics to overcome the drawbacks of conventional methods. The present study compared dentinal defects formed by rotary systems in primary teeth. Methods. Eighty primary teeth were included. The teeth were decoronated with a diamond disc. All the roots were inspected for any pre-existing cracks or craze lines under transmitted light under a stereomicroscope. The specimens were then divided into four groups (n=20): group 1: control, group 2: hand files (HF), group 3: ProTaper files, and group IV: SAF files. The samples were instrumented according to the group they were assigned to. Results. The HF and SAF groups exhibited fewer microcracks. Dentinal microcracks were observed in roots prepared with rotary ProTaper files. There were significant differences between HF/SAF and rotary files (P < 0.05). Conclusion. Stainless steel hand K-files and SAF instruments resulted in fewer dentinal damage than the ProTaper Universal files. SAF exhibited satisfactory results with minimal or no crack formation. [ABSTRACT FROM AUTHOR]

Introduction: Apart from manual activation methods of irrigants during final irrigation procedure, multiple irrigant activation devices have been introduced which can influence the postoperative pain. Aim: To evaluate postoperative pain after final irrigation with open and closed-ended endodontic needles and Endoactivator during root canal treatment. Materials and Methods: This randomised controlled trial was conducted in Department of Conservative Dentistry and Endodontics, Bapuji Dental College and Hospital, Davangere, from June 2018 to August 2018. Total of 75 symptomatic irreversible pulpitis patients were randomly assigned into three groups. In group EN-1, final irrigation protocol was performed with 30-gauge notched tip needle (Pac-Dent, India), group EN-2 using side-vented, closed 30-gauge needle (Max-i-Probe, Dentsply, USA) and in group EA using Endoactivator (Dentsply, USA). Pain using Visual Analog Scale (VAS) was evaluated at 8, 24 and 48 hours. Participants were prescribed Non-steroidal Anti-Inflammatory Drugs (NSAIDs) as an escape medication. Comparison between the three groups at each time interval was done using Kruskal Wallis test followed by Mann-Whitney U test as post-hoc test. Change in VAS score over different time intervals (8, 24 and 48 hours) in each group was compared using Kruskal Wallis test and Mann-Whitney U test. The p-value less than 0.05 was considered statistically significant. SPSS version 20 was used for statistical analysis. Results: Mann-Whitney U test revealed significant difference between EN-1 and EN-2 (p=0.002) and between EN-1 and EA (p<0.001) at 8-hour time interval; between EN-1 and EA (p=0.002) at 24 hour time interval and between EN-1 and EN-2 (p=0.01) as well as between EN-1 and EA (p=0.002) at 48 hour time. Mann- Whitney U test showed significant difference (p<0.05) in number of NSAIDs taken at 8 hour between EN-1 and EA (p=0.04) and between EN-2 and EA (p=0.01); at 8-24 hour between EN-1 and EA and between EN-1 and EN-2 (p<0.001); at 24-48 hour between EN-1 and EA and between EN-1 and EN-2 (p<0.001). Conclusion: Number of NSAIDS taken by patients was significantly higher in open-ended needle irrigation group compared to side-vented needle and Endoactivator group in all the three time intervals along with postoperative pain. Thus, during final irrigant activation, application of Endoactivator or side-vented needle can be more beneficial in decreasing the incidence of postendodontic pain. [ABSTRACT FROM AUTHOR]

Aim: This in vitro study examined the effect of both early and late coronal flaring on the working length in curved root canals. Background: The objective of this study was to determine if canal length is altered as a result of coronal flaring (CF) in curved root canals. Study design: The conditions compared were combinations of (a) stainless steel hand files using Gates Glidden drills (SS) versus nickel-titanium rotary files (NiTi); and (b) early coronal flaring (flaring completed before working length determination) versus late coronal flaring (flaring completed after working length determination). Ninety canals of extracted first molars were selected, which were divided into three groups. Coronal flaring was accomplished for the SS group using Gates Glidden drills, and for the NiTi group using rotary ProTaper and HERO Shaper files (30 teeth per group). Working length was determined before coronal flaring, immediately after coronal flaring, and again after root canal preparation. Statistical analysis: Repeated measures of an analysis of variance (ANOVA) test and a Turkey's multiple post hoc test were used. Results: Results indicated that the working length decreased for all canals as a result of canal preparation. The mean decrease of working length was significantly greater for the SS group (-0.77 mm +/- 0.42) than for the NiTi group (-0.33 mm +/- 0.44). There was less change in working length in all groups when the initial working length was determined after coronal flaring. Conclusion: Working length in curved canals consistently decreased during the course of instrumentation. The clinician should keep this in mind for better treatment outcome. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to compare the root canal transportation of the crown-down technique performed with the Ni-Ti rotary ProFile system (Dentsply/Maillefer), with the step-back technique using stainless steel K-Flexofiles (Dentsply/Maillefer). Method and Materials: Thirty simulated root canals in resin blocks were equally divided into 2 groups. The first group was instrumented with the ProFile system in a crown-down technique and the second group with hand K-Flexofiles in a step-back technique. After instrumentation, resin blocks of both groups were scanned by a transparency scanner, and the derived images were superimposed with the scanned image of an uninstrumented block. Transportation was digitally calculated by a computer software, and results were statistically evaluated by Student t test. Results: Statistically significant differences (P < .05) were found among the 2 groups at 1, 2, 4, 5, and 6 mm from the apical foramen. No statistically significant difference was detected at 3 mm from the apical foramen. Conclusion: ProFile caused less transportation at 1 and 2 mm from the apex, whereas at 3 mm, both instrumentation techniques caused the same transportation. Standard deviation was less in the ProFile group than in the hand file group, indicating a more standardized preparation. [ABSTRACT FROM AUTHOR]

The objective of our study was to compare and assess the outcome of root canal preparation of maxillary molars with two nickel-titanium (NiTi) rotary systems using CBCT. Ten maxillary molars were selected for this study, randomly divided into 2 groups with respect to the angle of canal curvature and submitted to standardized radiographs and CBCT, before and after instrumentation with ProTaper Next (group 1) and One Shape (group 2). The canals were three-dimensionally reconstructed and evaluated for the following parameters: changes in canal volume, percentage of shaped canal walls and degree of canal transportation. Friedman One way ANOVA at 2mm, 5m and 8mm was used for the statistical analysis. There was no significant difference between the two groups before or after instrumentation. Both rotary systems were efficient and safe in shaping the root canals, without deviation of the original pathway of the canals. [ABSTRACT FROM AUTHOR]

This systematic review and meta-analysis investigated the influence of the number of files (full-sequence rotary-file versus reciprocating single-file systems) used during root canal preparation on the apical extrusion of debris and its biological relationship with the occurrence of symptomatic apical periodontitis. An extensive literature research was carried out in the Medline, ISI Web of Science and Cochrane databases, for relevant articles with the keyword search strategy. Based on inclusion and exclusion criteria, two reviewers independently rated the quality of each study determining the level of evidence of the articles selected. The primary outcome for the meta-analysis was determined by the amount of debris extruded into the periapical tissue during root canal preparation with multiple- or single-file systems in four laboratory studies. Analysis of in vivo release of neuropeptides ( SP and CGRP) after root canal preparation with single- or multiple-file systems was also carried out. Amongst the 128 articles initially found, 113 were excluded for being nonrelevant or not fulfilling the selection criteria. Another four articles were excluded after methodology evaluation. Finally, nine laboratory studies and two in vivo studies were included in the systematic review. Four of the laboratory studies were further included for meta-analysis that revealed greater debris extrusion after the use of single-file techniques when compared to multiple-file systems. Analysis of in vivo neuropeptide expression in the periodontal ligament suggests that the design of the instrument is more important than the number of files used. Both rotary and reciprocating single-file systems generate apical extrusion of debris in laboratory studies, or expression of neuropeptides in vivo. Available evidence is limited, but supports the fact that this inflammatory reaction is not influenced by the number of files but the type of movement and the instrument design. [ABSTRACT FROM AUTHOR]

Aim To test and compare the effectiveness and safety of two size 20, .04 taper rotary files that were used to create a glide path for the self-adjusting file (SAF) in curved canals of mandibular molars. Methodology Forty mandibular molars with curved mesial roots and narrow MB root canals were selected based on a passage of size 15 K-files to WL; size 20 K-files could not reach WL. Only roots with no visible microcracks were included. Two types of size 20 rotary files were used for glide path preparation, the new Pre-SAF size 20, .04 taper file and the ProFile size 20, .04 taper, which served as the reference and control. Both files were used with 3-4 pecking strokes, which brought them to WL. Two parameters were tested whether the glide path allowed manual insertion of a 1.5-mm SAF file to WL and whether the procedure caused microcracks in the root dentine. Paired t-tests were used to compare the groups. Results Glide path preparation with both files allowed the manual insertion of the SAF file to WL in all 20 root canals, with no difference between the two groups. No cracks were detected after the procedure in any of the roots in either group. Conclusions Both types of size 20, .04 taper rotary files were effective for glide path preparation for the SAF file in curved canals. Neither file type caused microcracks in root dentine. [ABSTRACT FROM AUTHOR]

Introduction The aim of this study was to evaluate the effects of large apical preparations in the danger zones of the mesial root canals of mandibular molars instrumented with the Mtwo and Reciproc systems (VDW, Munich, Germany) until reaching apical diameters of 0.25 and 0.40 mm. Methods Twelve mandibular molars, the mesial roots of which presented distinct foramens and similar anatomies, were selected using micro–computed tomographic scanning. Mtwo and Reciproc instruments were used to shape the mesiobuccal or mesiolingual canals. The mesial canals were scanned before and after the use of 0.25- and 0.40-mm Mtwo and Reciproc instruments. The analyzed parameters included the root canal volume and remaining dentin thickness at 5 different levels. The obtained data were subjected to paired analysis of variance and Tukey or Friedman and Dunn tests for intragroup analysis and the Mann-Whitney U test for comparison between the mesial and distal walls. Results There were no significant differences between the mesial and distal dentin thickness for the points analyzed with both instrumentation techniques ( P > .05). The volumetric analysis revealed a significant difference ( P < .05) among the initial volume and after the use of the 0.25- and 0.40-mm instruments for both systems. The use of the 0.40-mm instrument increased the root canal volume in comparison to the 0.25-mm instrument ( P < .05). Conclusions Both systems performed similarly for the preparation of curved root canals with separate apical foramens. The increase of the root canal preparation with the 0.40-mm instrument significantly increased the root canal volume at the apical third without significantly reducing the dentin thickness in the danger zone for both instrument systems. [ABSTRACT FROM AUTHOR]

Introduction: Preserving the apical root structure during cleaning and shaping of the canal has always been a challenge in endodontics particularly when the root canals are curved. The purpose of this in vitro study was to compare the apical transportation induced by the Reciproc and BioRaCe rotary systems in preparing the mesiobuccal root canal of the human maxillary molars. Materials and Methods: The mesiobuccal canals of sixty extracted maxillary molars with curvature angle of 25-35∘ were selected and randomly assigned into two groups. Each canal was prepared by either Reciproc or BioRaCe rotary systems. A double-digital radiographic technique and AutoCAD software were used to compare the apical transportation at 0.5, 1, 2, 3, 4 and 5 mm distances from the working length (WL). The distance between the master apical rotary file and the initial K-flle in the superimposed radiographs determined the amount of apical transportation. An independent t-test was used to compare the groups. The statistical significant level was set at 0.05. Results: Apical transportation of the Reciproc group was significantly greater than the BioRaCe group in all distances (P<0.001). The maximum apical transportation occurred in the Reciproc group at 0.5 mm from the WL (0.048±0.0028 mm) and the minimum occurred for BioRaCe at 5 mm from the WL (0.010±0.0005 mm). Conclusions: The Reciproc system produced significantly more apical transportation than the BioRaCe, but this fact does not seem to negatively alter the clinical success or quality of root canal treatment. [ABSTRACT FROM AUTHOR]

Aim: This in vitro investigation examined the effect of early coronal flaring (CF) and late CF on the working length (WL) in curved root canals. Background: The objective of this study was to determine if canal length is altered as a result of CF in curved canals of molar roots. Study Design: The conditions compared were combinations of (a) stainless steel hand files using Gates Glidden (G. G.) drills (SS) versus nickel-titanium rotary files (Ni-Ti); and (b) early CF (flaring completed before WL determination) versus late CF (flaring completed after WL determination). Selected were 90 canals of extracted maxillary or mandibular first molars (mesial root of mandibular molars and the mesiobuccal root of the maxillary molars) from three groups. CF was accomplished for the SS group using G. G. drills and for the Ni-Ti group using rotary ProTaper and Hero Shaper files. WL was determined by a digital vernier caliper before CF, immediately after CF, and again after canal preparation. Statistical Analysis: A repeated measures analysis of variance (ANOVA) test and a Tukey's multiple prosthoc test were used for this study. Results: Results indicated that WL decreased for all canals as a result of canal preparation. The mean decrease in WL was significantly greater for the SS group (-0.77 ± 0.42 mm) than for the Ni-Ti groups (-0.33 mm ± 0.44). Less change in WL occurred in all groups when initial WL was determined after CF. Conclusion: WL in curved canals consistently decreases during the course of instrumentation. Clinician should keep this in mind for better treatment outcome. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the shaping ability of ProFile 0.04 taper rotary nickel-titanium instruments with ISO sized tips in simulated canals. A total of 40 simulated root canals made up of four different shapes in terms of angle and position of curvature were prepared by ProFile instruments using the ‘crown down’ approach recommended by the manufacturer. Part 2 of this two-part report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation and the overall post-operative shape. Out of 37 completed specimens 9 zips (24%) and one ledge (3%) were created, but no perforations or danger zones were found. There were significant differences (P < 0.01) between canal shapes for the incidence of zips and elbows but not for their distance from the end-point of preparation. At specific positions along the canal length there were significant differences between the canal types in terms of their mean total width; overall, at the end-point of preparation and along the curved portion of the canals those specimens with 40° curves were widest. This trend continued for the width of material removed from the outer aspect of the canal curves, whereas along the inner aspect of curves more material was removed in the 20° canals. Overall, transportation was towards the outer aspect of the curve at the end-point of preparation and along the curved portion of canals but more balanced along the straight coronal section. Absolute transportation was small and below 0.1 mm at every position including the zips. Under the conditions of this study, ProFile nickel-titanium rotary instruments with ISO sized tips produced a larger number of zips than expected; however, the degree of zipping was limited and relatively minor. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the shaping ability of Quantec Series 2000 nickel-titanium instruments in simulated canals. A total of 40 simulated root canals made up of four different shapes in terms of angle and position of curvature were prepared by Quantec instruments using the technique recommended by the manufacturer. Part 1 of this two-part report describes the efficacy of the instruments in terms of preparation time, instrument failure, canal blockages, change in canal length and three-dimensional canal form. The time necessary for canal preparation was on average 5.7 min and was significantly influenced (P < 0.01) by canal shape. One instrument fractured and three size nine instruments deformed; however, canal shape did not influence significantly instrument failure. All of the canals remained patent, none became blocked with debris. The majority of the canals maintained working distance (26 out of 40), however the mean change in length differed significantly (P < 0.05) between canal types. Overall, canals with 40° curves lost length whilst those with 20° curves gained in length. Examination of intracanal impressions revealed that preparation with Quantec Series 2000 instruments produced canals with definite apical stops, smooth canal walls and good flow and taper. However, the quality of apical smoothness and flow was influenced significantly (P < 0.0001) by canal shape with specimens having 40° canals displaying less desirable qualities. Under the conditions of this study, Quantec Series 2000 rotary nickel-titanium instruments prepared simulated canals rapidly, safely and with good three-dimensional form. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the shaping ability of ProFile 0.04 taper rotary nickel-titanium instruments with ISO sized tips in simulated canals. A total of 40 simulated root canals made up of four different shapes in terms of angle and position of curvature were prepared by ProFile instruments using the ‘crown down’ approach recommended by the manufacturer. Part 1 of this two-part report describes the efficacy of the instruments in terms of preparation time, instrument failure, canal blockages, loss of canal length and three-dimensional canal form. The time necessary for canal preparation was on average 5.2 min and was not influenced significantly by canal shape. Three instrument fractures occurred and a further 3 instruments deformed; size 35 instruments failed the most (4) followed by size 30 (2), four of the failures occurred in canals with 40° curves. None of the canals became blocked with debris and change in working distance was minimal. Intra-canal impressions of canal form demonstrated that most canals had apical stops and smooth canal walls whereas all canals had good flow and taper. Under the conditions of this study, ProFile 0.04 taper rotary nickel-titanium instruments with ISO sized tips prepared simulated canals rapidly and created good three-dimensional form. [ABSTRACT FROM AUTHOR]

Background: To establish the extent of using nickel titanium rotary instruments (NiTi-RIs), to identify reasons for using / not using NiTi-RIs, to explore usage modalities and to identify factors and measures that can increase implementation of NiTi-RIs in general dental practice. Methods: Two pilot questionnaires were conducted on academic staff members at College of Dentistry, Taibah University, general dentists (GDs) and endodontists to finalise the questionnaire. A sample size was calculated considering the expected and minimum accepted response rates (60 and 48%, respectively) and a 99.9% Confidence Level. The online-questionnaire was sent to 600 GDs and all endodontists (175) working in Saudi Arabia. A reminder was emailed after 10 weeks to encourage non-respondents to complete the questionnaire. Responses, were collected and converted into numerical data which were analysed using the Chi-square test (p = 0.05). Results: Significantly most respondents (71.9%) used NiTi-RIs (p < 0.001); with more endodontists (96.9%) than GDs (60%). Most users (62.5%) had been using NiTi-RIs for More than 3 years (p < 0001). The trend of using NiTi-RIs increased as participants' experience and the number of root-canal treatments performed per week increased (p = 0.021). While most respondents (45.3%) used NiTi-RIs because of faster root-canal preparation, the majority of non-users (85.3%) didn't do so because of high cost. The highest proportion (43.3%) reported better undergraduate education as the most important factor that can significantly increase NiTi-RIs usage. The majority (91.8%) prepared glide-path before using NiTi-RIs; especially with stainless steel hand-files (63.3%). Conclusions: NiTi-RIs are relatively well adopted in Saudi dental practice. However, better education, especially during undergraduate training and lower cost can increase their usage. Overall, clinicians showed good awareness of NiTi-RIs usage aspects which reflected on usage modalities. [ABSTRACT FROM AUTHOR]

Abstract Mesgouez C, Rilliard F, Matossian L, Nassiri K, Mandel E. Influence of operator experience on canal preparation time when using the rotary Ni-Ti ProFile system in simulated curved canals. International Endodontic Journal , 36 , 161–165, 2003. Aim The aim of this study was to determine the influence of operator experience on the time needed for canal preparation when using a rotary nickel-titanium (Ni-Ti) system. Method A total of 100 simulated curved canals in resin blocks were used. Four operators prepared a total of 25 canals each. The operators included practitioners with prior experience of the preparation technique, and practitioners with no experience. The working length for each instrument was precisely predetermined. All canals were instrumented with rotary Ni-Ti ProFile Variable Taper Series 29 engine-driven instruments using a high-torque handpiece (Maillefer, Ballaigues, Switzerland). The time taken to prepare each canal was recorded. Significant differences between the operators were analysed using the Student's t -test and the Kruskall–Wallis and Dunn nonparametric tests. Results Comparison of canal preparation times demonstrated a statistically significant difference between the four operators (P < 0.001). In the inexperienced group, a significant linear regression between canal number and preparation time occurred. Conclusion Time required for canal preparation was inversely related to operator experience. [ABSTRACT FROM AUTHOR]

Abstract Bergmans L, Van Cleynenbreugel J, Beullens M, Wevers M, Van Meerbeek B, Lambrechts P. Smooth flexible versus active tapered shaft design using NiTi rotary instruments. International Endodontic Journal , 35 , 820–828, 2002. Aim The aim of this study was to evaluate the influence of a smooth flexible versus active tapered shaft design on canal preparation by NiTi rotary techniques. Methodology A XMCT-scanner (SkyScan 1072) and developed software (Bergmans et al . 2001) were used to nondestructively analyze the mesial canals of 10 extracted mandibular molars in 3D with a spatial resolution of 30 µm. Specimens (n = 10 per group) were scanned before (PRE) and after (POST) preparation using Lightspeed (smooth flexible) or GT-rotary (active tapered) files. Numerical values for volumes, dentine removal (net) transportation and centring ability were obtained in addition to a visual inspection on canal aberrations. Data were analyzed by Shapiro Wilk test, multiway factorial anova, Tukey–Kramer test, Wilcoxon test and t -test. Results Results indicated that the active tapered shaft removed significantly more dentine in the middle to apical portion of the root compared to the smooth flexible design. Both groups demonstrated some straightening, but no significant differences were found with respect to instrument types. However, absolute values for net transportation and centring ratio were small and no canal aberrations could be found. Conclusions The smooth flexible shaft design did not improve the morphological characteristics of canal preparation by NiTi rotary instruments when compared with the active tapered design. Therefore, system selection should be based upon other criteria. [ABSTRACT FROM AUTHOR]