Cyclic Fatigue Resistance of Blue Heat-Treated Instruments at Different Temperatures

The main aim is to evaluate the cyclic fatigue resistance of blue heat-treated instruments with different kinematics. Twenty-four endodontic instruments of the same brand were used for each of three experimental groups: VB (Vortex Blue 40/0.04), RB (RECIPROC Blue 40/0.06), and XB (X1 Blue 40/0.06). The instruments were randomly distributed and subjected to temperatures of 20°C and 37°C. The fatigue test was performed using a stainless steel device. Data were analysed using the Shapiro–Wilk test, Student’s t-test, the F test, and Tukey’s and Tamhane tests at significance level P = 0.05 . The instruments’ cyclic fatigue resistance at both temperatures differed significantly for each instrument type ( P < 0.001 ). The RB instruments displayed greater cyclic fatigue resistance at the tested temperatures compared with the VB and XB instruments ( P < 0.001 ). Reciprocating kinematics positively influenced cyclic fatigue resistance. Blue heat-treated instruments showed decreased cyclic fatigue resistance as the temperature increased ( P < 0.001 ).

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Comparison of Cyclic Fatigue Resistance of Five Heat Treated NiTi Rotary Systems in Single and Double Curved Canals.

10.21203/rs.3.rs-600840/v1 ◽

2021 ◽

Author(s):

Mohammad Al-Obaida ◽

Khalid Merdad ◽

Ali Alkhamis ◽

Muneer Khan Mohammed ◽

Rahaf Al-Obaida ◽

...

Keyword(s):

Fatigue Resistance ◽

Fatigue Testing ◽

Cyclic Fatigue ◽

Radius Of Curvature ◽

Double Curvature ◽

Heat Treated ◽

Separation Pattern ◽

Vortex Blue ◽

Number Of Cycles ◽

Post Hoc

Abstract BackgroundThe aim of this study was to compare cyclic fatigue resistance (CFR) and separation patterns during rotating movement of five heat-treated nickel titanium files in both single and double-curved canals. MethodsCFR was compared between five groups of 24 files each: HyFlex® EDM, HyFlex™ CM, Vortex Blue®, Protaper Next®, and One Curve, by determining the time needed to fracture (TTF) and the number of cycles to failure (NCF) in a cyclic fatigue testing device with a single 5-mm radius of curvature (ROC) and 60° angle, and a double curvature; coronal curvature (5 mm ROC and 60° angle) and apical curvature (2 mm ROC and 70° angle). The separation pattern was evaluated, and file fragment separated length were measured. One-way ANOVA and Tukey’s post-hoc were used to compare statistical differences between the groups. Scanning Electron Microscope (SEM) was used to investigate the fracture sites. Results HyFlex™ CM files displayed significantly higher CFR, followed by HyFlex® EDM and Vortex Blue® in single curvature canals, and Protaper Next® (PTN) in the double curvature canals, as observed by TFF and NCF. PTN group had the highest tendency for files to extrude apically after separation in both curvatures. ConclusionHyFlex™ CM instruments have superior resistance to cyclic flexural fatigue within single canals with single and double curvatures, followed by HyFlex® EDM and Vortex Blue® instruments. Protaper Next® files followed by One Curve had the highest tendency to extrude apically after separationClinical relevanceHyFlex™ CM instruments showed the highest safety in preparing canals with single or double curvatures, considering CFR.

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Evaluation of the Cyclic Fatigue of Two Single Files at Body and Room Temperature with Different Radii of Curvature

Materials ◽

10.3390/ma14092256 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2256

Author(s):

Giusy Rita Maria La Rosa ◽

Valeria Shumakova ◽

Gaetano Isola ◽

Francesco Indelicato ◽

Calogero Bugea ◽

...

Keyword(s):

Fatigue Resistance ◽

In Vitro Study ◽

Cyclic Fatigue ◽

Curvature Radius ◽

Significance Level ◽

Rotary Instruments ◽

Significant Difference ◽

Different Temperatures ◽

Two Temperatures

Background: To compare the influence of different temperatures and curvature radii on the cyclic fatigue resistance of F6 SkyTaper (F6ST) and One Curve (OC) single file nickel-titanium rotary instruments. Methods: A total of 120 instruments of F6ST and OC #25.06 were evaluated in 5 mm and 3 mm curvature radii at two temperatures (20 °C ± 1 °C and 37 °C ± 1 °C) in 16 mm stainless steel artificial canals associated with a curvature of 60°. The cyclic fatigue of tested files was assessed by employing a customized testing apparatus and expressed as times to fracture (TtF). A statistical analysis was performed with the significance level set at 95%. Results: All instruments decreased their TtF at 37 °C except for OC in the 3 mm radius, in which no significant difference was detected between 20 °C and 37 °C. A 3 mm curvature radius negatively affected TtF of all tested instruments, except for F6ST at 20 °C. F6ST had higher TtF than OC in the 3 mm radius at 20 °C, with no significant difference between them in the other tested conditions. Conclusions: Under the limits of the present in vitro study, body temperature impaired cyclic fatigue resistance of all files, except for OC in the 3 mm curvature radius. All instruments exhibited lower times to fracture in the 3 mm radius, excluding F6ST at 20 °C.

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The Effect of Multiple Autoclave Sterilization on the Cyclic Fatigue of Three Heat-Treated Nickel-Titanium Rotary Files: EdgeFile X7, Vortex Blue, and TRUShape

BioMed Research International ◽

10.1155/2020/8826069 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Reham Sharroufna ◽

Mohammed Mashyakhy

Keyword(s):

Fatigue Resistance ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

The Other ◽

Heat Treated ◽

Significant Difference ◽

The Mean ◽

Vortex Blue ◽

Number Of Cycles ◽

Cycles To Failure

Objective. The purpose of this study was to evaluate the effect of repeated autoclave sterilization on the cyclic fatigue resistance of heat-treated NiTi rotary endodontic instruments. Materials and Methods. Three NiTi rotary endodontic instruments (EdgeFile X7, EFX7 0.30/0.4; Vortex Blue, VB 0.30/0.4; and TRUShape, TS 0.30/0.6) were selected. Each group ( n = 24 each) was divided into 2 subgroups ( n = 12 each): sterilized instruments and nonsterilized instruments. The sterilized instruments were subjected to 10 cycles of autoclave sterilization. Twelve instruments from each different subgroups were tested for cyclic fatigue resistance, and the number of cycles to failure (NCF) was calculated. Means and standard deviations were calculated for each group, and data were statistically analyzed using the SPSS program ( P < 0.05 ). Results. Sterilized and nonsterilized EFX7 files showed the highest NCF compared with other file subgroups. Comparing the results between sterilized and nonsterilized instruments for each type of files, there was a statistically significant difference ( P < 0.05 ) only between sterilized and nonsterilized EFX7 files (1198 versus 755 NCF). The other instruments did not show significant differences ( P > 0.05 ) in the mean NCF as a result of sterilization cycles (VB, 606 versus 568 NCF; TS, 487 versus 442 NCF). Conclusion. Repeated cycles of autoclave sterilization increased the NCF of the new heat-treated files, with EFX7 showing statistically significant superior results compared with other files tested.

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Shaping and Centering Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Three Thermally Treated NiTi Endodontic Instrument Systems

Materials ◽

10.3390/ma13245823 ◽

2020 ◽

Vol 13 (24) ◽

pp. 5823

Author(s):

Saulius Drukteinis ◽

Vytaute Peciuliene ◽

Ruta Bendinskaite ◽

Vilma Brukiene ◽

Rasmute Maneliene ◽

...

Keyword(s):

Fatigue Resistance ◽

Cyclic Fatigue ◽

Fractographic Analysis ◽

Significance Level ◽

Root Canals ◽

Topographic Features ◽

New Instrument ◽

Before And After ◽

Number Of Cycles ◽

Thermally Treated

The better understanding of the clinically important behavioral features of new instrument systems has an important significance for the clinical endodontics. This study aimed to investigate the shaping and centering ability as well as cyclic fatigue resistance of HyFlex CM (CM), HyFlex EDM (EDM) and EdgeFile (EF) thermally treated nickel–titanium (NiTi) endodontic instrument systems. Sixty curved root canals of the mesial roots of mandibular molars were randomly assigned into three groups (n = 20) and shaped using CM, EDM and EF files up to the size 40 and taper 04 of the instruments. µCT scanning of the specimens before and after preparation was performed and the morphometric 2D and 3D parameters were evaluated in the apical, middle and coronal thirds of root canals. In each group, 40.04 instruments (n = 20) were subjected to the cyclic fatigue resistance test in artificial root canals at 37 °C temperature until fractures occurred, and the number of cycles to failure (NCF) was calculated. The fractographic analysis was performed using a scanning electron microscope, evaluating topographic features and surface profiles of the separated instruments. The one-way analysis of variance with post hoc Tuckey’s test was used for statistical analysis of the data; the significance level was set at 5%. All systems prepared the comparable percentage of root canal surface with the similar magnitude of canal transportation in all root thirds (p > 0.05), but demonstrated significantly different resistance to cyclic fatigue (p < 0.05). The most resistant to fracture was EF, followed by EDM and CM. The length of the fractured fragments was not significantly different between the groups, and fractographic analysis by SEM detected the typical topographic features of separated thermally treated NiTi instrument surfaces.

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Safety and Effectiveness of Additional Apical Preparation using a Rotary Heat-treated Nickel–Titanium file with Larger Diameter and Minimum Taper in Retreatment of Curved Root Canals

European Journal of Dentistry ◽

10.1055/s-0041-1723065 ◽

2021 ◽

Author(s):

Jader Camilo Pinto ◽

Fernanda Ferrari Esteves Torres ◽

Airton Oliveira Santos-Junior ◽

Marco Antonio Hungaro Duarte ◽

Juliane Maria Guerreiro-Tanomaru ◽

...

Keyword(s):

Fatigue Resistance ◽

Continuous Wave ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Filling Material ◽

Root Canals ◽

Filling Materials ◽

Heat Treated ◽

Before And After ◽

Curved Root Canals

Abstract Objective The aim of this study was to investigate the effect of additional apical preparation using the ProDesign Logic (PDL) 50/.01 rotary heat-treated nickel–titanium (NiTi) file with a larger diameter and minimal taper for retreatment of curved root canals. Materials and Methods Mesial curved root canals of 12 mandibular molars were prepared using PDL 25/.06 and filled using the continuous wave of condensation technique and AH Plus sealer. After retreatment using ProDesign S (PDS) 25/.08, PDL 25/.06 and PDL 35/05, a complementary procedure was performed with PDL 50/.01. Microcomputed tomography (micro-CT) scanning was performed before and after retreatment procedures. The cyclic fatigue resistance of unused PDS 25/.08, PDL 25/.06, PDL 35/.05 and PDL 50/.01 instruments (n = 12) was evaluated in a stainless-steel device. Statistical Analysis Data on the volumes of the root canals and the remaining filling materials were submitted to the paired t-test. Cyclic fatigue resistance data was submitted to one-way ANOVA and Tukey’s tests (α = 0.05). Results Use of PDL 50/.01 decreased the remaining filling materials in the apical third (p < 0.05). The root canal volume was similar in the cervical and middle thirds before and after preparation using PDL 50/.01 (p > 0.05). PDL 50/.01 presented the highest cyclic fatigue resistance (p < 0.05). Conclusions Use of the PDL 50/.01 instrument as an additional apical preparation for retreatment of curved root canals improved filling material removal in the apical third, while maintaining the dentin in the cervical and middle thirds. In addition, PDL 50/.01 presented high-flexural resistance.

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Comparison of the cyclic fatigue resistance of ProGlider, PathGlider and One G path-finding instruments

Journal of Dental Research Dental Clinics Dental Prospects ◽

10.15171/joddd.2019.009 ◽

2019 ◽

Vol 13 (1) ◽

pp. 57-60

Author(s):

Damla Özsu Kırıcı ◽

Ertuğrul Karataş ◽

Ahmet Demirhan Uygun ◽

Ezgi Doğanay Yıldız ◽

Kezban Meltem Çolak ◽

...

Keyword(s):

Stainless Steel ◽

Fatigue Test ◽

Fatigue Resistance ◽

Root Canal ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Curvature Radius ◽

System A ◽

Post Hoc ◽

G 14

Background. The aim of the present study was to compare the cyclic fatigue resistance of novel nickel titanium rotary pathfinding instruments. Methods. Twenty instruments were selected for each file system. A simulated stainless steel root canal, with a 90° angle of curvature and a curvature radius of 3 mm, was used for cyclic fatigue test of the ProGlider (#16, progressive taper: 0.02‒ 0.085), PathGlider (#15, taper: .03), and One G (#14, taper: .03) instruments. Statistical analyses were performed with oneway ANOVA (P=0.05). Post hoc Tukey tests were used to determine any statistically significant differences between the groups. Results. The ProGlider instruments exhibited significantly more cyclic fatigue resistance than both PathGlider and One G instruments (P<0.001). One G instruments had significantly more resistance to fracture than PathGlider instruments (P<0.05). Conclusion. ProGlider instruments had better cyclic fatigue resistance than PathGlider and One G instruments.

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The nasal index in brazilian human skeletons

Brazilian Journal of Oral Sciences ◽

10.20396/bjos.v17i0.8654156 ◽

2018 ◽

Vol 17 ◽

pp. e18337 ◽

Cited By ~ 1

Author(s):

Larissa Chaves Cardoso Fernandes ◽

Marcus Vitor Diniz de Carvalho ◽

Eduardo Daruge Júnior ◽

Luiz Francesquini Júnior ◽

Patrícia Moreira Rabello ◽

...

Keyword(s):

Mixed Race ◽

Cross Sectional Study ◽

Brazilian Population ◽

Cross Sectional ◽

Significance Level ◽

Human Skulls ◽

Student’S T ◽

Digital Caliper ◽

Student’S T Test

Aim: To investigate the percentage of correctness (PC) of the Nasal Index (NI) in human skeletons for determination of sex, ancestry and estimation of age in the Brazilian population. Methods: This was a cross-sectional study of 173 human skulls belonging to the Piracicaba Dental School. 93 skeletons were males and 80 females; 34 were aged up to 39 years, 56 between 40 and 59 years, and 83 60 years or older; 96 were from white individuals, 49 were from mixed-race and 28 from black individuals. High-precision digital caliper was used to measure nasal height (NH=ANS-nasion) and the maximum nasal width (NW) values, which were applied into the formula NI=NW/NHx100. The data were submitted to discriminant analysis and Student’s t test with equal variances, Mann-Whitney, F (ANOVA), Tukey and Kruskal Wallis, 5% significance level. Results: Dominant nasal type in the Brazilian population was the mesorine. Males showed nasal height and width values greater than those of females, with statistically significant differences in all measurements (p≤0.021) and PC of 76.6%. Similar nasal measurements were found regardless of age (p>0.05), with PC of 41.7%. Ancestral analysis revealed that black individuals have greater nasal width (26.35) and nasal index (53.67) than white ones (24.60 and 49.25), while mixed-race individuals showed intermediate values (25.36 and 52.13) (p<0.05). Nevertheless, these measurements presented an estimated PC of 54.3%. Conclusion: The Nasal Index can be better used for sex determination than for estimation of age and ancestry in the Brazilian population, as the latter showed intermediate and low percentage of correctness, respectively.

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

Materials ◽

10.3390/ma14195734 ◽

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.

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Craniometric study of the Orbital Index in brazilian skulls

RGO - Revista Gaúcha de Odontologia ◽

10.1590/1981-86372021001320190115 ◽

2021 ◽

Vol 69 ◽

Author(s):

Larissa Chaves Cardoso FERNANDES ◽

Patrícia Moreira RABELLO ◽

Bianca Marques SANTIAGO ◽

Marcus Vitor Diniz de CARVALHO ◽

Manoel Raimundo de SENA JÚNIOR ◽

...

Keyword(s):

Mixed Race ◽

Cross Sectional Study ◽

Southeastern Brazil ◽

Cross Sectional ◽

Significance Level ◽

Brazilian Sample ◽

Significant Difference ◽

Student’S T ◽

The Right ◽

Student’S T Test

ABSTRACT Objetive To determine the percentage of correctness of the Orbital Index (OI) for estimation of sex, ancestry and age in Brazilian skulls. Methods Cross-sectional study of 183 human dry skulls from the southeastern Brazil. A total of 100 skeletons were males and 83 females; of which 36 were aged up to 39 years, 60 aged between 40 and 59 years, and 87 aged 60 years or older. As for ancestry, 103 were from white, 51 mixed race, and 29 black individuals. The OI was calculate by the formula = height/width x 100. The data were submitted to Student’s t test, F (ANOVA), Tukey and Kruskal Wallis tests as well as to discriminant analysis, with a 5% significance level. Results The sample was characterized as mesoseme, with a mean age of 56.62 (±19.97) years. No significant difference was observed (p=0.511) between the OI in females (right: 86.43 ± 6.58 and left: 86.70 ± 5.93) and males (right: 85.78 ± 6.69 and left: 86.37 ± 6.20). There were no significant differences between age, ancestry and the variables analyzed (p>0.05). The right and left orbital widths were significantly dimorphic between sexes (p<0.001). The percentage of correctness of the method for estimation of sex, age and ancestry was found to be 65.6%, 43.7%, and 43.6%, respectively. Conclusions The OI is not an appropriate method for estimation of sex, ancestry and estimation of age in this Brazilian sample. The methodology should be expanded to other population groups so that it can be improved.

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