scholarly journals Ex-Vivo Comparison of Torsional Stress on Nickel–Titanium Instruments Activated by Continuous Rotation or Adaptive Motion

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1900 ◽  
Author(s):  
Joo Yeong Lee ◽  
Sang Won Kwak ◽  
Jung-Hong Ha ◽  
Hyeon-Cheol Kim
Keyword(s):  
Ex Vivo ◽  
Control Unit ◽  
Nickel Titanium ◽  
Stress Generation ◽  
Torsional Stress ◽  
Significance Level ◽  
Glide Path ◽  
Continuous Rotation ◽  
Adaptive Motion ◽  
Shaping Procedure

This study aimed to evaluate the effect of adaptive motion applied to conventional nickel-titanium (NiTi) rotary instruments on torsional stress generation during shaping procedure. One hundred and twenty mesio-buccal canals of molars were randomly assigned to two groups according to the kinetics; adaptive motion (AD) and continuous rotation (CR). Each group was divided into four subgroups (n = 15) according to the NiTi instrument systems: HyFlex EDM, One Curve, Twisted File Adaptive, and ProTaper Next. A glide path was established with PathFile #1, for each file group being used with either of the kinetic movements. During the instrumentation with the designated motion and file system, the generated torque was measured via the control unit and acquisition module. Based on the acquired data, the maximum and total torque were calculated. The data were statistically analyzed using Kruskal–Wallis and Mann–Whitney tests at a significance level of 95%. The maximum and total torque generated by all instruments were significantly reduced by the adaptive motion (p < 0.05). In the CR group, HyFlex EDM generated the highest maximum and total stress. In the AD group, HyFlex EDM showed the highest maximum torsional stress, and One Curve showed the highest total torsional stress (p < 0.05). The TF Adaptive instrument with adaptive movement produced the lowest maximum and total torsional stress (p < 0.05). Under the conditions of this study, the use of adaptive motion would be useful to reduce the torsional stress of instrument and root dentin. The reduction of torsional stress through adaptive motion may enhance the durability of instruments and reduce the potential risk of dentinal cracks.

scholarly journals Effective Establishment of Glide-Path to Reduce Torsional Stress during Nickel-Titanium Rotary Instrumentation

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 493 ◽  
Author(s):  
Ibrahim H Abu Tahun ◽  
Sang Won Kwak ◽  
Jung-Hong Ha ◽  
Asgeir Sigurdsson ◽  
Mehmet Baybora Kayahan ◽  
...  
Keyword(s):  
Nickel Titanium ◽  
Stress Generation ◽  
Total Stress ◽  
Significance Level ◽  
Glide Path ◽  
Working Length ◽  
Canal Shaping ◽  
The One ◽  
Data Acquisition Module ◽  
Post Hoc

This study compared the torque generation during canal shaping with a nickel-titanium endodontic instrument according to the extent of glide-path establishment. Seventy-five simulated S-shaped canal blocks were divided into five groups (n = 15) according to the number of repetitive insertions to the working length using a One G glide-path instrument: groups with 5, 10, 15, and 20 insertions as well as group Z without glide-path establishment. When the tip of the One G file reached the working length, the file was moved back and forth repetitively at the working length for the designated number of times for each group. The instrumentation procedure with HyFlex EDM had 15 pecking strokes. During instrumentation, the generated torque was transmitted to a customized data acquisition module and collected using customized software. Data were computed to determine the maximum torque and total stress. The maximum screw-in forces were statistically analyzed using one-way analysis of variance and Tukey’s post hoc comparison test with a significance level of 95%. While the maximum stress did not have significant differences among the five groups (p > 0.05), groups with more than 10 repetitive insertions generated lower total stress during instrumentation than did the group with 5 insertions and group Z (p < 0.05). Under the limitations of this study, repetitive insertions of glide-path establishment files at the working length reduced stress generation during the shaping using nickel-titanium instruments.

scholarly journals Effect of Core Mass and Alloy on Cyclic Fatigue Resistance of Different Nickel-Titanium Endodontic Instruments in Matching Artificial Canals

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5734
Author(s):  
Sebastian Bürklein ◽  
Lennart Zupanc ◽  
David Donnermeyer ◽  
Karsten Tegtmeyer ◽  
Edgar Schäfer
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
The Other ◽  
Design Parameters ◽  
Core Mass ◽  
Cross Sectional ◽  
Significance Level ◽  
Cross Sectional Design ◽  
The Impact

Instrument failure during root canal preparation is still a concern among endodontists. However, it remains unclear whether the use of more martensitic alloys or the cross-sectional design parameters (i.e., core mass) significantly improve fracture resistance. The aim of the study was to evaluate the impact of core mass and alloy on dynamic cyclic fatigue resistance of nickel-titanium endodontic instruments in matching artificial canals at body temperature. Two groups were tested. (A) taper 0.04: F360 (Komet, Lemgo, Germany), Twisted file (Sybron Endo, Glendora, CA, USA) (=TF), JIZAI (Mani, Tochigi, Japan) (=J_04) (all size #25) and the variable tapered TruNatomy (Dentsply, Ballaigues, Switzerland) (size #26) (=TN). (B) size #25; taper 0.06: (Mtwo (VDW, Munich, Germany), JIZAI (Mani) (=J_06), and variable tapered Hyflex EDM OneFile (Coltene Whaledent, Altstätten, Switzerland) (=HF). Time, number of cycles to fracture (NCF), and number and length of fractured fragments were recorded and statistically analysed using ANOVA Student-Newman-Keuls, Kruskal–Wallis or Chi-square test (significance level = 0.05). (A) TN showed the significantly shortest time until fracture, followed by TF, F360 and J_04 which also differed significantly, while NCF showed the following order: F360 < TN < TF < J_04 (p < 0.05). Only one J_04 but all instruments of the other groups fractured within the test-limit of 10 min. (B) Mtwo was significantly inferior concerning time until fracture and NCF, compared to J_06 and HF (p < 0.05), which did not differ significantly (p > 0.05). While all Mtwo instruments fractured, only four instruments failed in the other groups (p < 0.05). Within the limitations of this study, alloy and cross-sectional design (i.e., core mass) were critical factors regarding instrument failure, but none of these factors could be determined as a main parameter for increased or decreased time, and cycles to fracture. Rather, it seemed to be the interaction of multiple factors (e.g., longitudinal and cross-sectional design, alloy, and rotational speed) that was responsible for differences in the time and cycles to fracture. Nonetheless, all instruments had lifetimes that allow safe clinical use. However, the superiority or inferiority of an instrument with regard to cyclic fatigue based on laboratory results—even when identical trajectories are guaranteed—may be considered questionable, as the characteristics and design parameters of the instruments vary considerably, and the experimental setups lack additional clinical parameters and thus clinical relevance.

scholarly journals Factors influencing incidents of complications while using nickel-titanium rotary instruments for root canal treatment

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Ahmad A. Madarati
Keyword(s):  
Root Canal ◽  
Nickel Titanium ◽  
Influential Factor ◽  
Common Complication ◽  
Pilot Studies ◽  
Significance Level ◽  
Rotary Instruments ◽  
Chi Squared ◽  
Final Questionnaire ◽  
General Dentists

Abstract Background To investigate the complications associated with the use of nickel titanium rotary instruments (NiTi-RIs) for root canal treatments (RCTs), in Saudi Arabia dental practice, and to explore the influencing factors. Methods After obtaining an ethical approval, two pilot studies were conducted to formulate the final questionnaire. The sample size was measured taking into consideration 60% expected response rates and confidence level of 99.9%. The questionnaire was emailed to 600 general dentists (GDs) randomly selected from the dental register and all of the endodontists (175). The email’s introduction clarified objectives of the study and guaranteed that all of the collected information would remain confidential. A reminder was sent after 10 weeks. The data were collected and analyzed using the chi-squared test at a 0.05 significance level. Results With a 51% overall response rate, 71.9% off the respondents used NiTi-RIs. The majority (83.1%) experienced complications while using NiTi-RIs; with the instruments’ fracture being significantly the most common complication (52.7%) (p < 0.001). The majority (87.7%) experienced NiTi-RIs’ fractureat least once; with more endodontists (94.3%) than GDs (83.3%) (p < 0.001). The greater the number of weekly performed RCTs and participants’ experiences, the more NiTi-RIs fractures and the greater the number of fracture incidents (p < 0.001). While 60% of those who performed 1–3 RCTs per week experienced NiTi-RIs fractures, 100% of those who performed more than 12 RCTs per week did so. The highest percentage of those who experienced more than 10 fractured NiTi-RIs (60%) was within the group who performed more than 12 RCTs per week. Although fracture incidents decreased with a smaller number of reuses, there was no significant correlation between the number of fractured instruments and NiTi-RIs discard strategy (p ≥ 0.05). Conclusion Fracture incidence was the most common complication while using NiTi-RIs, regardless of the clinicians’ experiences and skills. While the single use may reduce NiTi-RIs fractures, to some extent, the greater number of RCTs performed per week was the most influential factor.

Effect of Glide Path Creating on Cyclic Fatigue Resistance of Reciproc and Reciproc Blue Nickel-titanium Files: A Laboratory Study

2018 ◽  
Vol 44 (6) ◽  
pp. 1033-1037 ◽  
Author(s):  
Taha Özyürek ◽  
Gülşah Uslu ◽  
Koray Yılmaz ◽  
Mustafa Gündoğar
Keyword(s):  
Fatigue Resistance ◽  
Laboratory Study ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Glide Path

scholarly journals Radiographic analysis of root canal fillings: influence of two sealers on the perception of voids

2010 ◽  
Vol 21 (2) ◽  
pp. 142-147 ◽  
Author(s):  
Augusto Bodanezi ◽  
Etiene de Andrade Munhoz ◽  
Norberti Bernardineli ◽  
Ana Lúcia Álvares Capelozza ◽  
Ivaldo Gomes de Moraes ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Root Canal ◽  
Ex Vivo ◽  
Radiographic Analysis ◽  
Radiographic Images ◽  
Significance Level ◽  
Root Canals ◽  
Gutta Percha ◽  
Root Canal Sealers

The aim of this ex vivo was to investigate if two radiopaque root canal sealers with different formulations would influence the radiographic perception of root canal fillings. The root canals of 48 extracted maxillary canines were prepared and randomly assigned to 3 groups of 16 specimens each. In each group, the root canals were filled by lateral condensation of gutta-percha and one of the tested sealers: Endométhasone, Sealer 26, or a non-radiopaque sealer. A through-and-through void was simulated in half of the specimens from each group (n=8). The buccolingual radiographic images obtained were randomly interpreted for voids existence by a radiologist and an endodontist. The differences in sensitivity and specificity between groups and examiners were compared using, respectively, Fisher's Exact and McNemar tests at 5% significance level. Both radiopaque sealers caused a significant decrease in sensitivity at the coronal part of fillings. The use of Endométhasone increased specificity values for both coronal and apical portions of the root canal fillings. In conclusion, the tested sealers influenced the radiographic perceptions of laterally condensed root canal fillings in a different way.

scholarly journals Tooth Discoloration after Regenerative Endodontic Procedures with Calcium Silicate-Based Cements—An Ex Vivo Study

2020 ◽  
Vol 10 (17) ◽  
pp. 5793
Author(s):  
Paulo J. Palma ◽  
Joana A. Marques ◽  
Joana Santos ◽  
Rui I. Falacho ◽  
Diana Sequeira ◽  
...  
Keyword(s):  
Calcium Silicate ◽  
Color Change ◽  
Ex Vivo ◽  
Mineral Trioxide Aggregate ◽  
Critical Factor ◽  
Color Variation ◽  
Significance Level ◽  
Tooth Discoloration ◽  
Biomaterial Application ◽  
Ex Vivo Study

The aim of the present ex vivo study was to assess and compare coronal discoloration induced by four endodontic biomaterials used in regenerative endodontic procedures (REPs). Root resection was executed horizontally, 2 mm apical to the cementoenamel junction, in all fifty-four teeth. After accessing the pulp chamber, specimens were randomly divided in groups and filled with either saline solution or blood, followed by calcium silicate-based cements (CSCs) placement: ProRoot mineral trioxide aggregate (MTA) (Dentsply Sirona), Biodentine (Septodont), TotalFill BC (FKG), or pulp capping material (PCM) (Coltène). Color change (ΔE) was assessed using the L* a* b* system at five different timepoints (before and immediately after biomaterial application, 72 h, 7 days, and 6 months). The significance level for statistical analysis was set at p < 0.05. There are statistically significant differences regarding ΔE over time (p < 0.001). Statistical differences are found considering material (p < 0.001), treatment (p = 0.007), or both (p = 0.002). If solely the material or treatment is considered, regardless of time, statistically significant differences are detected (p < 0.001). After a six-month period of evaluation, blood exposure might be a critical factor in biomaterials’ color variation. Biodentine presents the lowest discoloration potential, followed by TotalFill and PCM, albeit without statistically significant differences. MTA exhibited the greatest color variation. The selection of biomaterial should consider the material’s discoloration potential.

Use of Nickel-Titanium Rotary PathFile to Create the Glide Path: Comparison With Manual Preflaring in Simulated Root Canals

2009 ◽  
Vol 35 (3) ◽  
pp. 408-412 ◽  
Author(s):  
Elio Berutti ◽  
Giuseppe Cantatore ◽  
Arnaldo Castellucci ◽  
Giorgio Chiandussi ◽  
Francesco Pera ◽  
...  
Keyword(s):  
Nickel Titanium ◽  
Root Canals ◽  
Glide Path
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