The introduction of nickel-titanium rotary instruments revolutionized shaping procedures as they were able to produce a well-tapered preparation while reducing operator fatigue. The major drawback of rotary instruments was the high risk of fracture due to bending and torsional stress. Thus, the creation of a glide path has been advocated and recommended by most rotary instrument manufacturers. The aim of the present review is to summarize existing knowledge on glide path preparation and identify areas where further research is needed. The primary goal is to provide a comprehensive overview of the techniques and instruments used in glide path preparation, highlighting their advantages and limitations. The secondary goal is to explore the effect of glide path creation on the overall success of endodontic treatment, particularly in terms of reducing procedural errors and improving treatment outcomes. An online search on PubMed, ScienceDirect, UCLA, and Scopus databases was conducted, and 116 articles were identified. Eligible articles were divided into nine categories based on what they researched and compared. The categories included centering ability and/or root canal transportation, cyclic fatigue resistance, glide path and shaping time, tortional stress resistance, apical extrusion of debris and/or bacteria, defects in dentine walls, file separation, postoperative pain assessment, and scouting ability and performance. Establishing a glide path reduces root canal transportation, especially with rotary methods. Reciprocating and heat-treated files offer higher fatigue resistance and shorter preparation time. Instruments with shorter pitch lengths have greater torsional strength. Preparation and coronal preflaring reduce apical debris and bacteria. Glide paths do not affect dentine microcracks, file separation, or defects but reduce immediate postoperative pain and improve cutting ability. Randomized trials are needed to assess their impact on treatment outcomes.

Small-sized stainless steel hand files are conventionally employed in root canal treatment procedures for canal scouting and for glide path establishment, owing to their superior flexibility and proficiency in navigating confined spaces. Given the diversity of brands available in the market, there exists potential variability in their physical characteristics, thereby influencing clinical performance. Consequently, this study aims to conduct a comparative analysis of the design, metallurgy, and mechanical characteristics among seven stainless steel hand file brands across ISO sizes 06, 08, and 10. A total of 315 new 25 mm length stainless steel hand files with apical sizes of 0.06, 0.08, and 0.10 from seven distinct brands were included in the study. A meticulous inspection of all instruments was undertaken to identify any structural deformations that might render them ineligible for the study. The design inspection involved the random selection of instruments from each group, which were examined under various microscopes, including a dental operating microscope, optical microscope, and scanning electron microscope. Furthermore, two instruments from each group underwent energy-dispersive X-ray spectroscopy analysis for elemental composition documentation. Mechanical tests were conducted to evaluate the instruments\' resistance to lateral deformation (buckling) and their microhardness. Statistical analysis was executed using the nonparametric Mood\'s median test, with a predetermined significance level of 0.05. Regarding the instruments design, all files exhibited an active blade length ranging from 16 to 17 mm. However, variations were observed in the number of spirals, tip designs, and sizes, with the API K-File notably larger in sizes 0.06 and 0.08 compared to the other instruments. Despite uniform elements composition, differences in geometric features and mechanical properties were evident. Concerning buckling strength, the API K-File demonstrated superior performance across all tested sizes, while the Dentsply ReadySteel, SybronEndo, and Mani K-Files exhibited lower results (p < 0.05). In microhardness assessments, both the API and Oro K-Files displayed the lowest outcomes, with medians of 531 HVN and 532 HVN, respectively, whereas the SybronEndo K-File exhibited the highest microhardness (657 HVN). Despite similar metallurgical composition, the observed distinctions in geometric features and mechanical properties underscore the impact of the manufacturing process on the characteristics of glide path stainless steel endodontic files. These disparities may ultimately influence their clinical performance.

To establish a glide path, smaller files (up to size 0.15) with tapers of 2% are commonly used as pathfinding files. They pre-shape the root canal space before transitioning to larger taper endodontic instruments, aiming to prevent procedural errors. This study aimed to compare the design, metal wire composition, and mechanical characteristics of seven different ISO size 15 stainless-steel hand files (K-File and C-File+). Ninety-one new stainless-steel ISO 15 K-files were mechanically tested. All files were inspected for deformations before the assessment. Dental operating microscope, scanning electron microscope (SEM), and optical microscope analyses were conducted on four randomly selected instruments from each group, and two instruments per group underwent an energy-dispersive X-ray spectroscopy (EDS) analysis. Buckling mechanical tests were performed using an Instron universal testing machine, and microhardness was assessed using a Vickers hardness tester. The statistical analysis employed the nonparametric Mood\'s median test, with a significance level set at 0.05. The instrument design analysis unveiled variations in the active blade area length and the number of spirals, while maintaining consistent cross-sections and symmetrical blades. Distinct tip geometries and surface irregularities were observed. While the energy-dispersive X-ray spectroscopy confirmed similar compositions, the buckling strength and microhardness values exhibited variability across for all tested files. Notably, the Dentsply ReadySteel C-File+ recorded the highest buckling value (2.10 N), and the Dentsply ReadySteel K-File exhibited the lowest (1.00 N) (p < 0.05). Moreover, the Dentsply ReadySteel K-File recorded the highest microhardness value (703 HVN), while the SybronEndo Triple-Flex had the lowest (549 HVN) (p < 0.05). While similarities in cross-section design and metal wire composition were noted among the files, variations in the number of spirals and mechanical performance were also observed. Thus, all of these factors should be considered when selecting suitable files for an efficient root canal treatment.

This study aimed to compare the shaping ability of different instruments, TruNatomy Glider (TRN-G), WaveOne Gold Glider (WOG-G), and ProGlider (Pro-G) using micro-computed tomography (micro-CT).
The mesial canals of 27 mandibular molars with two separate mesial canals and moderate curvature were included in this study [n = 27 mesiobuccal (MB) and mesiolingual (ML) root canal]. According to the manufacturer\'s instructions, the glide path was created with TRN-G, WOG-G, and Pro-G glide path instruments (n = 9 MB and ML root canal in each group). Micro-CT scanning was performed before and after preparation. Mesiodistal (MD) and buccolingual (BL) transportation and the centering ratio were measured at three levels within the canal (3, 5 and 7 mm). A three-way robust ANOVA was used to compare the parameters.
TRN-G showed significantly greater transportation in the MD direction than the other instruments throughout the root canal (overall root canal) (p < 0.05). The best centering ability in the BL direction was shown by the WOG-G, regardless of level within the canal and canal distinction (MB vs. ML) (p < 0.05). There was no significant difference between groups according to the level within the canal and canal parameters (p > 0.05). Whether the root canal was MB or ML did not affect centering or transportation (p > 0.05).
Glide path instruments can be used to shape moderately curved canals with minimal apical transportation and better centering ability. All three tested glide path files can used safely before the shaping file.

UNASSIGNED: The glide path instruments are the introductory instruments into the canals; thus, they should be durable enough to withstand torsional stress/screw-in force. This study aimed to investigate the torque and screw-in force of TruNatomy Glider (TN), ProGLIDER (PG), Hyflex EDM (EDM) and Dent Craft RE (RE) glide path instruments in single- and double-curved canals.
UNASSIGNED: Each instrument brand was divided into two groups (n = 7 each) according to the canal configuration. Torque and screw-in force were recorded during automated instrumentation of simulated resin canals with XSmart IQ cordless motor after the canal patency was checked with a #10 K-file. The values were statistically analyzed using the Kolmogorov-Smirnov test followed by the Kruskal Wallis test and the Mann-Whitney U test with Bonferroni correction (α = 0.05).
UNASSIGNED: TN produced significantly higher torque than RE in single-curved canals and PG in double-curved canals (P < 0.05). EDM yielded significantly higher screw-in force than TN and RE in single-curved canals (P < 0.05), but there was no significant difference in double-curved canals (P > 0.05). A significant effect of different canal configurations was only detected for screw-in force in EDM (P < 0.05).
UNASSIGNED: TN in single-curved canals and RE in double-curved canals yielded higher torque values, while EDM exhibited greater screw-in force in both canal configurations. No effect of different canal configurations was detected for torque, but a significant impact was detected for screw-in force in EDM.

It is essential to create a glide path before root canal preparation with nickel-titanium rotary files to avoid file breakage and preserve the original canal structure. The aim of this study was to compare the amount of apically extruded debris after using different glide path files. A total of 96 first mandibular molars with curved mesial roots were randomly divided into six groups (n = 16) which are K-files, Proglider, R-Pilot, TruNatomy Glider, WaveOne Gold Glider and group without a glide path. Apically extruded debris was measured after glide path and canal preparation. The highest amount of debris was found in the control group without a glide path and using a glide path file caused less debris and significant differences were observed between R-Pilot, TruNatomy Glider, ProGlider, WaveOne Gold Glider and K-file groups. It may be recommended to create a glide path before root canal shaping to reduce the amount of extrusion debris from the apical. Especially in curved and narrow root canals, it is recommended to use an R-Pilot file before root canal shaping in order to reduce the amount of apically extruded debris.

UNASSIGNED: This study aimed to compare the changes in root canal anatomy following the use of PathFile and R-Pilot using cone-beam computed tomography (CBCT).
UNASSIGNED: In this in vitro, experimental study, 60 extracted maxillary first and second molars with 20 to 40° mesiobuccal root curvature, minimum of 19 mm of root length, no calcified root canals and no history of previous treatment were divided into two groups (n=30). CBCT scans were taken before and after the treatment, and sections at 1, 2 and 3 mm from the apex were compared. Pairwise comparisons were carried out using the Mann Whitney-U test. The centering ratio data were analyzed using the Chi-square test and Fisher\'s exact test. All statistical analyses were carried out using Sigma Stat 4 software.
UNASSIGNED: The difference between PathFile and R-Pilot in canal transportation in mesiodistal direction was significant at 1 and 2 mm from the apex (P<0.01). The R-Pilot file was significantly superior to PathFile in centering ability in mesiodistal direction at 1 mm from the apex (P<0.05). Canal transportation direction was towards the mesiolingual and distobuccal in R-Pilot and PathFile groups, respectively.
UNASSIGNED: Within the limitations of this study, the results showed that R-Pilot with reciprocal movement is a safe and easy to use instrument for creating a glide path.

OBJECTIVE: The aim of this study was to compare the ability of undergraduate students to reach working length (WL) in second mesiobuccal root canals (MB2) of maxillary first molars (n = 210) by using Reciproc Blue without glide path preparation, and One Curve with glide path preparation.
METHODS: The students (n = 105) attended theoretical and practical courses. The first group (n = 53) shaped MB2 root canals using the One Curve system and then Reciproc Blue; the second group (n = 52) shaped MB2 root canals following the reverse sequence. Participants completed a questionnaire. The chi-square and Mann-Whitney U test were used for statistical analysis using significance of p < 0.05.
RESULTS: The full WL was reached and shaping procedures were completed without complications in Reciproc Blue and One Curve groups at rates of 86.67% and 82.85%, respectively (p > 0.05). Treatment time was shorter in Reciproc Blue (p < 0.05). More (62.9%) students felt the One Curve system safer, while 61% felt the Reciproc Blue system faster.
CONCLUSIONS: Within the limitations of this study, instrument kinematics and glide path preparation did not interfere with undergraduate students\' ability to achieve the WL in MB2 root canals.

We document a reduction in both the level and cross-sectional dispersion of systematic risk in the target-date fund (TDF) market after 2008, which resulted in better performance of TDFs during the COVID-19 selloff compared to the 2008 selloff and a reduction in TDF return dispersion. We find that the shift is more pronounced in close-to-retirement funds and driven by the TDF series investing more in equities in the early period, consistent with TDFs catering to the market demand for lower risk exposure after the 2008 crisis. In addition, TDF systematic risk shifters do not exhibit more idiosyncratic risk-taking.

Recently, various kinds of heat-treated nickel-titanium (NiTi) glide path instruments have been manufactured. This study aimed to investigate design, phase transformation behavior, mechanical properties of TruNatomy Glider (#17/02), V Taper 2H (#14/03), and HyFlex EDM (#15/03) and compare torque/force generated during simulated glide path preparation with them.
The designs and phase-transformation behaviors of the instruments were examined via scanning electron microscopy (n = 3) and differential scanning calorimetry (n = 2). Their bending (n = 15), torsional (n = 15), and cyclic fatigue resistances (n = 15) were tested. The ultimate strength and distortion angle were obtained from torsional resistance test. The number of cycles to failure (NCF) was calculated from cyclic fatigue resistance test. The preparation of the glide path was simulated using a double-curved artificial canal (n = 15), and the maximum torque and screw-in forces were measured. Data except NCF was compared between brands with one-way ANOVA with Tukey\'s honestly significant difference test. NCF was analyzed via Kruskal-Wallis and Mann-Whitney U tests.
TruNatomy Glider had the greatest number of threads. TruNatomy Glider showed progressive taper, while V Taper 2H and HyFlex EDM had constant taper. The austenitic transformation-finish temperatures of all the instruments were above body temperature. V Taper 2H demonstrated significantly lower ultimate strength, higher distortion angle, and a higher number of cycles to failure compared with HyFlex EDM and TruNatomy Glider (p < 0.05). The maximum torque generated during preparing glide path was lowest for V Taper 2H, and the maximum screw-in force was lowest for HyFlex EDM (p < 0.05). TruNatomy Glider generated the highest torque and screw-in force during the apical preparation.
V Taper 2H #14/03 showed superior cyclic fatigue resistance and lower ultimate strength. TruNatomy Glider generated greater clockwise torque and screw-in force during apical preparation. The mechanical properties, torque, and screw-force was affected by design of heat-treated glide path instruments. Cervical pre-flaring prior to glide path instrument is recommended.