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Dos Reis FAS, Abu Hasna A, Ragozzini G, de Moura FB, Campos TMB, de Martin AS, Carvalho CAT, Bueno CES. Assessing the cyclic fatigue resistance and sterilization effects on replica-like endodontic instruments compared to Reciproc Blue. Sci Rep 2023; 13:22956. [PMID: 38151487 PMCID: PMC10752872 DOI: 10.1038/s41598-023-50096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/15/2023] [Indexed: 12/29/2023] Open
Abstract
This study aimed to evaluate the effect of the number of uses and autoclave sterilization on the cyclic fatigue resistance of four replica-like instruments RC Blue; Only One File Blue; Recip One Blue; and Micro Blue compared to the original system Reciproc Blue (VDW, Munich, Germany). The instruments were analyzed by scanning electron microscope (SEM) before being used in root canal instrumentation (baseline). Fifty molars were instrumented by ten instruments (n=10). After sterilization in an autoclave, the instruments were analyzed by SEM. This procedure was repeated twice more using different molars, totaling 3 rounds of instrumentation, sterilization and SEM analysis. Then, ten different instruments from each brand were tested for cyclic fatigue resistance. Number of uses data were analyzed using Chi-squared analysis, and cyclic fatigue data were analyzed by one-way Anova followed by Tukey's test as the data had normal distribution. The fracture times for all systems had no significant difference, but Micro Blue had significantly lower values than the other systems (p < 0.05). The SEM analysis showed distortions in the instruments after the 3rd use. Therefore, all tested instruments except of Micro Blue have similar resistance to cyclic fatigue, and all are reliable for use in up to 2-cases.
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Affiliation(s)
| | - Amjad Abu Hasna
- Department of Restorative Dentistry, Endodontics Division, Institute of Science and Technology, São Paulo State University (UNESP), Av. Eng. Francisco José Longo Avenue 777, São José dos Campos, SP, CEP 12245-000, Brazil.
- School of Dentistry, Universidad Espíritu Santo, Samborondón, Ecuador.
| | - Gustavo Ragozzini
- Faculdade São Leopoldo Mandic, Instituto de Pesquisas São Leopoldo Mandic, Endodontia, Campinas, SP, Brazil
| | - Felipe Bernardo de Moura
- Department of Restorative Dentistry, Endodontics Division, Institute of Science and Technology, São Paulo State University (UNESP), Av. Eng. Francisco José Longo Avenue 777, São José dos Campos, SP, CEP 12245-000, Brazil
| | | | | | - Cláudio Antonio Talge Carvalho
- Department of Restorative Dentistry, Endodontics Division, Institute of Science and Technology, São Paulo State University (UNESP), Av. Eng. Francisco José Longo Avenue 777, São José dos Campos, SP, CEP 12245-000, Brazil
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dos Reis FAS, Abu Hasna A, Ragozzini G, de Moura FB, Campos TMB, de Martin AS, Carvalho CAT, Bueno CES. Assessing the cyclic fatigue resistance and sterilization effects on replica-like endodontic instruments compared to Reciproc Blue. Sci Rep 2023; 13:22956. [DOI: https:/doi.org/10.1038/s41598-023-50096-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/15/2023] [Indexed: 01/17/2024] Open
Abstract
AbstractThis study aimed to evaluate the effect of the number of uses and autoclave sterilization on the cyclic fatigue resistance of four replica-like instruments RC Blue; Only One File Blue; Recip One Blue; and Micro Blue compared to the original system Reciproc Blue (VDW, Munich, Germany). The instruments were analyzed by scanning electron microscope (SEM) before being used in root canal instrumentation (baseline). Fifty molars were instrumented by ten instruments (n=10). After sterilization in an autoclave, the instruments were analyzed by SEM. This procedure was repeated twice more using different molars, totaling 3 rounds of instrumentation, sterilization and SEM analysis. Then, ten different instruments from each brand were tested for cyclic fatigue resistance. Number of uses data were analyzed using Chi-squared analysis, and cyclic fatigue data were analyzed by one-way Anova followed by Tukey’s test as the data had normal distribution. The fracture times for all systems had no significant difference, but Micro Blue had significantly lower values than the other systems (p < 0.05). The SEM analysis showed distortions in the instruments after the 3rd use. Therefore, all tested instruments except of Micro Blue have similar resistance to cyclic fatigue, and all are reliable for use in up to 2-cases.
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Metallurgical Tests in Endodontics: A Narrative Review. Bioengineering (Basel) 2022; 9:bioengineering9010030. [PMID: 35049739 PMCID: PMC8773015 DOI: 10.3390/bioengineering9010030] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Since there are no reviews of the literature on this theme, the aim of this narrative review is to summarize the metallurgical tests used in endodontics, pointing out their functional use and their pros and cons and giving readers a user-friendly guide to serve as an orientation aid in the plethora of metallurgical tests. With this purpose, a literature search for articles published between January 2001 and December 2021 was conducted, using the electronic database PubMed to collect all published articles regarding the metallurgical tests used in endodontics for the evaluation of NiTi rotary instruments. The search was conducted using the following keywords: “metallurgy”, “differential scanning calorimetry” (DSC), “X-ray diffraction” (XRD), “atomic force microscopy” (AFM), “energy-dispersive X-ray spectroscopy” (EDS), “focused ion beam analysis” (FIB) and “Auger electron spectroscopy” (AES) combined with the term “endodontics” or “NiTi rotary instruments”. Considering the inclusion and exclusion criteria, of the 248 articles found, only 81 were included in the narrative review. According to the results, more than 50% of the selected articles were published in one of the two most relevant journals in endodontics: International Endodontic Journal (22.2%) and Journal of Endodontics (29.6%). The most popular metallurgical test was DSC, with 43 related articles, followed by EDS (33 articles), AFM (22 articles) and XRD (21 articles). Few studies were conducted using other tests such as FIB (2 articles), micro-Raman spectroscopy (4 articles), metallographic analysis (7 articles) and Auger electron spectroscopy (2 articles).
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Abstract
A very extensive literature review presents the possibilities and needs of using, in endodontics, the alloys commonly known as nitinol. Nitinol, as the most modern group of engineering materials used to develop root canals, is equilibrium nickel and titanium alloys in terms of the elements’ atomic concentration, or very similar. The main audience of this paper is engineers, tool designers and manufacturers, PhD students, and students of materials and manufacturing engineering but this article can also certainly be used by dentists. The paper aims to present a full material science characterization of the structure and properties of nitinol alloys and to discuss all structural phenomena that determine the performance properties of these alloys, including those applied to manufacture the endodontic tools. The paper presents the selection of these alloys’ chemical composition and processing conditions and their importance in the endodontic treatment of teeth. The results of laboratory studies on the analysis of changes during the sterilization of endodontic instruments made of nitinol alloys are also included. The summary of all the literature analyses is an SWOT analysis of strengths, weaknesses, opportunities, and threats, and is a forecast of the development strategy of this material in a specific application such as endodontics.
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Management of Instrument Sterilization Workflow in Endodontics: A Systematic Review and Meta-Analysis. Int J Dent 2020; 2020:5824369. [PMID: 32148504 PMCID: PMC7035513 DOI: 10.1155/2020/5824369] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 01/08/2020] [Indexed: 12/26/2022] Open
Abstract
Endodontic treatment consists of different working procedures, such as the isolation of the operating field, pulp chamber access, and cleaning and shaping phases with at last the need of a three-dimensional filling of the canals. Each step requires a series of single-use or sterilizable instruments. We have performed a systematic review of different sterilization and disinfection procedures aiming at drawing up a disinfection and sterilization procedure to be used on endodontic instruments. A search on PubMed and Scopus was carried out using the following keywords: “endodontic sterilization,” “endodontic autoclave,” “decontamination dental bur,” “sterilization dental burs,” and “gutta-percha points sterilization.” Eligible articles were included in the qualitative and quantitative analysis. Results of the meta-analysis showed that the most effective method in sterilization is autoclaving. The qualitative analysis showed that the use of single-use or first-use instruments requires presterilization or sterilization procedures, and for reusable tools, attention must be paid to the removal of debris deposited on the blades, not easy to remove manually.
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Torsional and Bending Properties of V Taper 2H, ProTaper NEXT, NRT, and One Shape. BIOMED RESEARCH INTERNATIONAL 2019; 2019:6368958. [PMID: 31828110 PMCID: PMC6881565 DOI: 10.1155/2019/6368958] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 10/17/2019] [Indexed: 11/18/2022]
Abstract
Nickel-titanium (NiTi) rotary files have enabled efficient root canal preparations that maintain the canal center with fewer aberrations compared to hand files. However, NiTi rotary files are susceptible to fracture, which can thereby compromise root canal treatment. Therefore, NiTi files have been developed to enhance fracture resistance by modifying design and thermal treatment. The objective of this study was to compare the torsional fatigue resistance and bending resistance of NiTi files manufactured from different alloys and treatments. ProTaper NEXT X2 (PTN; M-wire), V taper 2H (V2H; controlled memory wire), NRT (heat-treated), and One Shape (OS; conventional alloy) instruments of tip size #25 were compared. Torsional fatigue was evaluated by embedding the 3 mm tip of each instrument (N = 10/brand) in resin and the repetitive application of torsional stress (300 rpm, 1.0 N·cm) by an endodontic motor with autostop when the file fractured. The number of loading cycles to fracture was recorded and analyzed by Kruskal–Wallis and Mann–Whitney U tests with Bonferroni's correction. Bending resistance of the instruments was tested using a cantilever bending test to the 3 mm point from the tip (N = 10/brand). The stress was measured when deflection of 3 mm was subjected and statistically analyzed with a one-way analysis of variance and Tukey's honest significance difference test (α = 0.05). V2H withstood the highest number of load applications during torsional fatigue testing (p < 0.05), followed by NRT, PTN, and OS, where the differences between NRT and PTN (p=0.035) and between PTN and OS (p=0.143) were not statistically significant. V2H showed the lowest bending stiffness, followed by NRT, PTN, and OS (p < 0.001). Thermal treatment of NiTi wire resulted in improved mechanical properties, and controlled memory wire provided improved flexibility and torsional fatigue resistance.
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da Silva Vieira B, Cançado RH, Freitas KM, Valarelli FP, Gobbi RC, de Oliveira RCG. Effect of Clinical Use and Sterilization Process on the Transition Temperature Range of Thermally NiTi Alloys. Open Dent J 2019. [DOI: 10.2174/1874210601913010261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
Thermally activated nickel-titanium wires have been widely used by orthodontists due to more constant forces, generation over longer activation spans, greater resistance to permanent deformation, superelasticity characteristics when cyclically loaded, better spring-back and less hysteresis.
Objective:
The purpose of this study was to evaluate the influence of clinical use and sterilization process on the Transition Temperature Range (TTR) of thermoset nickel-titanium wires using Differential Scanning Calorimetry (DSC).
Methods:
Sections from four nickel-titanium wires (0.019 × 0.025-inch) belonging to four different brands were assessed in four different states. Two of the wires were assessed in the “as received” state, one after 60 days of clinical use, and one after 60 days of clinical use and subjected to a sterilization process (autoclaving). The segments of each archwire were tested using DSC at temperatures ranging from −80°C to 150°C at a rate of 10°C/min.
Results:
All the nickel-titanium memory thermoset wires presented with desirable property for clinical use. The shape memory property was not influenced by clinical use and sterilization process.
Conclusion:
There was no change in TTR of the nickel-titanium wires after clinical use and sterilization.
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Yılmaz K, Uslu G, Özyürek T. Effect of multiple autoclave cycles on the surface roughness of HyFlex CM and HyFlex EDM files: an atomic force microscopy study. Clin Oral Investig 2018; 22:2975-2980. [PMID: 29442187 DOI: 10.1007/s00784-018-2382-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/06/2018] [Indexed: 11/28/2022]
Abstract
AIM To compare the effect of autoclave cycles on the surface topography and roughness of HyFlex CM and HyFlex EDM instruments using atomic force microscopy (AFM) analysis. METHODOLOGY Eight new files of each brand were subdivided into four subgroups (n = 2/each subgroup). One group was allocated as the control group and not subjected to autoclave sterilization. The other three groups were subjected to different numbers (1, 5, and 10) of autoclave sterilization cycles. After the cycle instruments were subjected to AFM analysis. Roughness average (Ra) and the root mean square (RMS) values were chosen to investigate the surface features of endodontic files. The data was analyzed using one-way ANOVA and post hoc Tamhane tests at 5% significant level. RESULTS The lowest Ra and RMS values were observed in the HyFlex EDM files that served as the control and in those subjected to a single cycle of autoclave sterilization (P < 0.05). The highest Ra and RMS values were observed in the HyFlex CM and HyFlex EDM files that were subjected to 10 cycles of autoclave sterilization (P < 0.05). The surface roughness values of the HyFlex CM group showed a significant increase after ten autoclave cycles, whereas those of the HyFlex EDM group exhibited a significant change after five autoclave cycles (P < 0.05). CONCLUSIONS Although the initial surface roughness values of the HyFlex EDM files were lower than those of the HyFlex CM files, the surface roughness values of the EDM files showed a statistically significant increase after 5 cycles of autoclave sterilization. In contrast, the surface roughness values of the HyFlex CM files did not increase until 10 cycles of autoclave sterilization. CLINICAL RELEVANCE Present study indicated that autoclave sterilization negatively affected the surface roughness of the tested NiTi files.
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Affiliation(s)
- K Yılmaz
- Çorum Oral and Dental Centre, Çorum, Turkey
| | - G Uslu
- Special Dental Clinic, Çanakkale, Turkey.
| | - T Özyürek
- Department of Endodontics, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey
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Razavian H, Iranmanesh P, Mojtahedi H, Nazeri R. Effect of Autoclave Cycles on Surface Characteristics of S-File Evaluated by Scanning Electron Microscopy. IRANIAN ENDODONTIC JOURNAL 2015; 11:29-32. [PMID: 26843874 PMCID: PMC4731530 DOI: 10.7508/iej.2016.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 08/16/2015] [Accepted: 09/01/2015] [Indexed: 11/30/2022]
Abstract
Introduction: Presence of surface defects in endodontic instruments can lead to unwanted complications such as instrument fracture and incomplete preparation of the canal. The current study was conducted to evaluate the effect of autoclave cycles on surface characteristics of S-File by scanning electron microscopy (SEM). Methods and Materials: In this experimental study, 17 brand new S-Files (#30) were used. The surface characteristics of the files were examined in four steps (without autoclave, 1 autoclave cycle, 5 autoclave cycles and 10 autoclave cycles) by SEM under 200× and 1000× magnifications. Data were analyzed using the SPSS software and the paired sample t-test, independent sample t-test and multifactorial repeated measures ANOVA. The level of significance was set at 0.05. Results: New files had debris and pitting on their surfaces. When the autoclave cycles were increased, the mean of surface roughness also increased at both magnifications (P<0.05). Moreover, under 1000× magnification the multifactorial repeated measures ANOVA showed more surface roughness (P<0.001). Conclusion: Sterilization by autoclave increased the surface roughness of the files and this had was directly related to the number of autoclave cycles.
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Affiliation(s)
- Hamid Razavian
- Department of Endodontics, Torabinejad Dental Material Research Center, Dental School, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Pedram Iranmanesh
- General Dentist, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Hamid Mojtahedi
- Student Research Committee, Dental School, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Rahman Nazeri
- Student Research Committee, Dental School, Isfahan University of Medical Sciences, Isfahan, Iran
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Nair AS, Tilakchand M, Naik BD. The effect of multiple autoclave cycles on the surface of rotary nickel-titanium endodontic files: An in vitro atomic force microscopy investigation. J Conserv Dent 2015; 18:218-22. [PMID: 26069408 PMCID: PMC4450528 DOI: 10.4103/0972-0707.157256] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/19/2015] [Accepted: 02/26/2015] [Indexed: 12/02/2022] Open
Abstract
Aims: To observe and study the effect of multiple autoclave sterilization cycles, on the surface of nickel-titanium (NiTi) files. Materials and Methods: The file used for this study was the Mtwo file (VDW) and ProTaper (Dentsply). The apical 5 mm of the files were attached to a silicon wafer and subjected to autoclave cycles under standardized conditions. They were scanned with an AFM after 1, 5, and 10 cycles. The unsterilized files were used as control, before start of the study. Three vertical topographic parameters namely maximum height (MH), root mean square (RMS) of surface roughness, and arithmetic mean roughness (AMR)were measured with the atomic force microscope (AFM). Analysis of variance along with Tukey's test was used to test the differences. Results: The vertical topographic parameters were higher for both the files, right after the first cycle, when compared with the control (P < 0.01). The surface roughness increased sharply for Mtwo when compared to ProTaper, though ProTaper had a rougher surface initially. Conclusions: The study confirmed that the irregularities present on the surface of the file became more prominent with multiple autoclave cycles, a fact that should be kept in mind during their reuse.
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Affiliation(s)
- Ashish Shashikant Nair
- Department of Conservative Dentistry and Endodontics, SDM College of Dental Sciences and Hospital, Sattur, Dharwad, Karnataka, India
| | - Mahima Tilakchand
- Department of Conservative Dentistry and Endodontics, SDM College of Dental Sciences and Hospital, Sattur, Dharwad, Karnataka, India
| | - Balaram Damodar Naik
- Department of Conservative Dentistry and Endodontics, SDM College of Dental Sciences and Hospital, Sattur, Dharwad, Karnataka, India
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Zheng D, Neoh KG, Shi Z, Kang ET. Assessment of stability of surface anchors for antibacterial coatings and immobilized growth factors on titanium. J Colloid Interface Sci 2013; 406:238-46. [PMID: 23810547 DOI: 10.1016/j.jcis.2013.05.060] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/30/2013] [Accepted: 05/04/2013] [Indexed: 01/09/2023]
Abstract
Titanium (Ti) has been functionalized with biomolecules for biomedical purposes. However, there is very limited information on the stability of such functionalities. Ti surface functionalized with carboxymethyl chitosan (CMCS) and bone morphogenetic protein 2 (BMP-2) has been reported to inhibit bacterial colonization while at the same time enhances osteoblast functions. In this work, three types of anchoring molecules, (3-aminopropyl) triethoxysilane (Silane), dopamine (DA), and polydopamine (PDA), were used for immobilizing the CMCS on Ti. The CMCS-modified surfaces were subjected to 70% ethanol treatment, autoclaving, and prolonged immersion in phosphate buffered saline (PBS). After the treatment procedures, the ability of the CMCS-modified substrates to inhibit colonization by Staphylococcus epidermidis (S. epidermidis) was assessed to evaluate the stability of the immobilized CMCS. The bacterial adhesion assays showed that the CMCS-DA- and CMCS-PDA-modified Ti remained stable after 70% ethanol treatment, autoclaving, and prolonged immersion in PBS, whereas the CMCS-Silane-modified Ti was less stable after autoclaving and prolonged immersion in PBS. The CMCS-DA- and CMCS-PDA-modified Ti substrates were functionalized with BMP-2 and used to support osteoblast growth. Evaluation of alkaline phosphatase (ALP) activity and calcium deposition from osteoblasts cultured on these substrates, which have been treated with 70% ethanol, or subjected to autoclaving, and prolonged immersion in PBS indicated that the immobilized BMP-2 on these surfaces retained its bioactivity.
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Affiliation(s)
- Dong Zheng
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 117576, Singapore
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Gu L, Zablocki K, Lavelle L, Bodnar S, Halperin F, Harper I, Moghe PV, Uhrich KE. Impact of ionizing radiation on physicochemical and biological properties of an amphiphilic macromolecule. Polym Degrad Stab 2012; 97:1686-1689. [PMID: 23162175 DOI: 10.1016/j.polymdegradstab.2012.06.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
An amphiphilic macromolecule (AM) was exposed to ionizing radiation (both electron beam and gamma) at doses of 25 kGy and 50 kGy to study the impact of these sterilization methods on the physicochemical properties and bioactivity of the AM. Proton nuclear magnetic resonance and gel permeation chromatography were used to determine the chemical structure and molecular weight, respectively. Size and zeta potential of the micelles formed from AMs in aqueous media were evaluated by dynamic light scattering. Bioactivity of irradiated AMs was evaluated by measuring inhibition of oxidized low-density lipoprotein uptake in macrophages. From these studies, no significant changes in the physicochemical properties or bioactivity were observed after the irradiation, demonstrating that the AMs can withstand typical radiation doses used to sterilize materials.
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Affiliation(s)
- Li Gu
- Rutgers, The State University of New Jersey, Department of Chemistry and Chemical Biology, 610 Taylor Road, Piscataway, New Jersey 08854, United States
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Shahi S, Mokhtari H, Rahimi S, Shiezadeh V, Ashasi H, Abdolrahimi M, Foroughreyhani M. Electrochemical corrosion assessment of RaCe and Mtwo rotary nickle-titanium instruments after clinical use and sterilization. Med Oral Patol Oral Cir Bucal 2012; 17:e331-6. [PMID: 22143690 PMCID: PMC3464121 DOI: 10.4317/medoral.17413] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 09/22/2011] [Indexed: 11/06/2022] Open
Abstract
Aim: The aim of the present study was to electrochemically evaluate corrosion resistance of RaCe and Mtwo files after repeated sterilization and preparation procedures.
Study Design: A total of 450 rotary files were used. In the working groups, 72 files from each file type were distributed into 4 groups. RaCe and Mtwo files were used to prepare one root canal of the mesial root of extracted human mandibular first molars. The procedure was repeated to prepare 2 to 8 canals. The following irrigation solutions were used: group 1, RaCe files with 2.5% NaOCl; group 2, RaCe files with normal saline; group 3, Mtwo files with 2.5% NaOCl; and group 4, Mtwo files with normal saline in the manner described. In autoclave groups, 72 files from each file type were evenly distributed into 2 groups. Files were used for a cycle of sterilization without the use of files for root canal preparation. Nine new unused files from each file type were used as controls. Then the instruments were sent for corrosion assessment. Mann-Whitney U and Wilcoxon tests were used for independent and dependent groups, respectively.
Results: Statistical analysis indicated that there were significant differences in corrosion resistance of files associated with working and autoclave groups between RaCe and Mtwo file types (p<0.001).
Conclusions: Corrosion resistance of #25, #30, and #35 Mtwo files is significantly higher than that in RaCe files with similar sizes.
Key words:Corrosion, NiTi instruments, autoclave, RaCe, Mtwo.
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Affiliation(s)
- S Shahi
- Department of Endodontics, Faculty of Dentistry, Golgasht Street, 5166614713, Tabriz, Iran
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Pirani C, Cirulli PP, Chersoni S, Micele L, Ruggeri O, Prati C. Cyclic fatigue testing and metallographic analysis of nickel-titanium rotary instruments. J Endod 2011; 37:1013-6. [PMID: 21689562 DOI: 10.1016/j.joen.2011.04.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 04/07/2011] [Accepted: 04/10/2011] [Indexed: 12/13/2022]
Abstract
INTRODUCTION The aim of this study was to compare cyclic fatigue resistance of four nickel-titanium rotary systems and to evaluate their surface, fractographic, and matrix morphology. METHODS Four models of endodontic rotary files (EasyShape [Komet/Gebr. Brasseler, Lemgo, Germany], ProTaper [Dentsply Maillefer, Ballaigues, Switzerland], NRT [MANI Inc, Toshigi-Ken, Japan], and AlphaKite [Komet/Gebr. Brasseler]) were subjected to fatigue testing in artificial canals with angle of curvature of 45° and 60° and a radius of curvature of 5 mm until fracture occurred. Nickel-titanium (NiTi) alloy properties were investigated by light microscopy, environmental scanning electron microscopy (ESEM), and energy dispersive x-ray spectrophotometry (EDS). ESEM analysis was conducted on new files to examine surface characteristics and on fractured samples to identify the crack origin and the fractographic features. RESULTS Analysis of variance testing revealed significant differences (P < .001) among the groups. NRT files had the highest fatigue resistance followed by AlphaKite, EasyShape, and ProTaper. All the new files presented surface imperfections. Fractographic analysis found the crack initiation to originate at the level of surface irregularities. Optical microscope inspection of the NiTi alloy matrix disclosed different-sized nonmetallic inclusions among models. EDS analysis of these inclusions showed that they were composed of carbon and oxygen in addition to nickel and titanium. Under light microscopy, austenitic grains appeared larger near the handle and smaller near the tip in all instruments. CONCLUSIONS NRT files presented the longest fatigue life. All samples showed surface irregularities and nonmetallic inclusions. Austenitic grains were smaller near the tip than near the handle. The angle of curvature was confirmed to influence the fatigue life of NiTi instruments.
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Affiliation(s)
- Chiara Pirani
- Department of Dental Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy.
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Zinelis S, Eliades T, Eliades G. A metallurgical characterization of ten endodontic Ni-Ti instruments: assessing the clinical relevance of shape memory and superelastic properties of Ni-Ti endodontic instruments. Int Endod J 2010; 43:125-34. [PMID: 20078701 DOI: 10.1111/j.1365-2591.2009.01651.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S Zinelis
- Department of Biomaterials, School of Dentistry, University of Athens, Athens, Greece.
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Fais LMG, Pinelli LAP, Adabo GL, Silva RHBTD, Marcelo CC, Guaglianoni DG. Influence of microwave sterilization on the cutting capacity of carbide burs. J Appl Oral Sci 2009; 17:584-9. [PMID: 20027431 PMCID: PMC4327518 DOI: 10.1590/s1678-77572009000600009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 07/21/2009] [Indexed: 11/21/2022] Open
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Elmsallati EA, Wadachi R, Suda H. Extrusion of debris after use of rotary nickel-titanium files with different pitch: A pilot study. AUST ENDOD J 2009; 35:65-9. [DOI: 10.1111/j.1747-4477.2008.00128.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Shen Y, Winestock E, Cheung GSP, Haapasalo M. Defects in Nickel-Titanium Instruments after Clinical Use. Part 4: An Electropolished Instrument. J Endod 2009; 35:197-201. [DOI: 10.1016/j.joen.2008.11.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 11/06/2008] [Accepted: 11/07/2008] [Indexed: 11/28/2022]
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Bui TB, Mitchell JC, Baumgartner JC. Effect of Electropolishing ProFile Nickel–Titanium Rotary Instruments on Cyclic Fatigue Resistance, Torsional Resistance, and Cutting Efficiency. J Endod 2008; 34:190-3. [DOI: 10.1016/j.joen.2007.10.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 10/16/2007] [Accepted: 10/23/2007] [Indexed: 11/30/2022]
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Abstract
AIM To examine the fatigue behaviour using a strain-life approach, and to determine the effect of water on the fatigue life of a NiTi rotary instrument. METHODOLOGY Instruments of one brand of NiTi engine-file (size 25, ProFile 0.04 and 0.06) were subjected to rotational bending either in air or under water, the number of revolutions to fracture (N(f)) being recorded using an optical counter and an electronic break-detection circuit. The effective surface strain amplitude (epsilon(a)) for each specimen was determined from the curvature of the instrument (on a photograph) and the diameter of the fracture cross-section (from a scanning electron micrograph of the fracture surface). Strain was plotted against fatigue life and the low-cycle fatigue (LCF) region identified. Values were examined using two-way analysis of variance for difference between various instrument-environment combinations. RESULTS A total of 212 instruments were tested. A strain-life relationship typical of metals was found. N(f) declined with an inverse power function dependence on epsilon(a). A fatigue limit was present at about 0.7% strain. The apparent fatigue-ductility exponent, a material constant for the LCF life of metals, was found to be between -0.45 and -0.55. There was a significant effect of the environmental condition on the LCF life, water being more detrimental than air. CONCLUSIONS The fatigue behaviour of NiTi rotary instrument is typical of most metals, provided that the analysis is based on the surface strain amplitude, and showed a high-cycle and a LCF region. The LCF life is adversely affected by water.
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Affiliation(s)
- G S P Cheung
- Family Dentistry & Endodontics, Faculty of Dentistry, The University of Hong Kong, HKSAR, China.
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