1
|
Toker SM, Orhan EO, Beklen A. Nickel ion release and surface analyses on instrument fragments fractured beyond the apex: a laboratory investigation. BMC Oral Health 2023; 23:703. [PMID: 37777753 PMCID: PMC10542686 DOI: 10.1186/s12903-023-03434-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/20/2023] [Indexed: 10/02/2023] Open
Abstract
BACKGROUND To analyse the changes in surface and nickel ion release characteristics of fractured root canal shaping instruments in a simulated body fluid environment. METHODS A total of 54 new instruments were studied. The instrument groups consisted of five different NiTi alloys and a stainless-steel alloy. To standardize instrument fracture, a torsional type of failure was created on each instrument. The fractured specimens of each instrument group were randomly divided into three static immersion subgroups of 1 h, 7-day, and 30-day (n = 3). Simulated body fluid (SBF) was prepared to mimic human blood plasma by Kokubo&Takadama protocol for ex situ static immersions at 37ºC. The surfaces were examined via scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. To determine the quantitative ion release, the retrieved SBFs were analyzed using inductively coupled plasma mass spectrometry. Two-way ANOVA and Tukey post hoc tests sought the statistical significance of the nickel ion values(p < 0.05). RESULTS In 1 h of immersion, the newly formed structures, exhibiting mostly oxygen signals, were widespread and evident on NiTi surfaces. In contrast, fewer structures were detected on the SS surface in that subgroup. In 7 days of immersion, a tendency for a decrease in the density of the new structures was revealed in NiTi groups. The oxygen signals on NiTi group surfaces significantly increased, contrary to their decrease in SS. Signals of sodium, chlorine, and calcium were detected, indicating salt precipitates in groups. In 30 days of immersion, salt precipitates continued to form. The Ni-ion release values in all instrument groups presented significant differences in comparison to the SBF control in all immersion periods(p < 0.001). No significant differences were observed in immersion time periods or instrument groups(p > 0.05). CONCLUSIONS Within the limitations of the presented study, it was concluded that the fractured SS and NiTi root canal instruments release Ni ions in contact with body fluid. However, the Ni ion release values determined during the observation periods are lower than the critical toxic or allergic thresholds defined for the human body. This was due to the ionic dissolution cycle reaching a stable state from 1-hour to 30-day exposure to the body fluid of fractured instruments.
Collapse
Affiliation(s)
- Sıdıka Mine Toker
- Metallurgical and Materials Engineering Department, Eskisehir Osmangazi University, Eskisehir, 26040, Turkey
| | - Ekim Onur Orhan
- Department of Endodontics, Faculty of Dentistry, Eskisehir Osmangazi University, Eskisehir, 26040, Turkey
| | - Arzu Beklen
- Department of Periodontology, Faculty of Dentistry, Eskisehir Osmangazi University, Eskisehir, 26040, Turkey.
- Translational Immunology Research Program (TRIMM), Research Program Unit (RPU), University of Helsinki, Helsinki, Finland.
| |
Collapse
|
2
|
Merima B, Ivona B, Dubravka M, Gianluca P, Ivica A. Surface roughness and cyclic fatigue resistance of reciprocating and novel rotary instruments after use in curved root canals. AUST ENDOD J 2022; 49:117-123. [PMID: 35605146 DOI: 10.1111/aej.12627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/05/2021] [Accepted: 05/05/2022] [Indexed: 12/14/2022]
Abstract
This study evaluated surface wear and resistance to fracture of reciprocating and novel rotary instruments after use in curved canals. Twenty new instruments (n = 5/each group): Reciproc Blue, WaveOne Gold, XP-endo Shaper (XPS) and TruNatomy were used twice for the instrumentation of simulated curved canals in plastic blocks. The instrumentation was performed according to the manufacturer's instructions at body temperature. Surface roughness was evaluated, using a profilometer, before instrumentation and twice after the instrumentation. Instruments were, then, subjected to a cyclic fatigue test to evaluate the time to failure. Differences were assessed using ANOVA and post hoc tests (α = 0.05). The XPS instruments showed significantly higher values of roughness compared with TruNatomy at every stage, especially after the second use (p < 0.008). Reciprocating instruments showed superior cyclic fatigue resistance compared with novel rotary instruments (p < 0.05). TruNatomy showed minimal surface roughness, and XPS exhibited significantly higher surface roughness.
Collapse
Affiliation(s)
- Balić Merima
- School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | - Bago Ivona
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| | | | - Plotino Gianluca
- Private Practice, Grande Plotino & Torsello - Studio di Odontoiatria, Rome, Italy
| | - Anić Ivica
- Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia
| |
Collapse
|
3
|
Kyaw MS, Ebihara A, Maki K, Kimura S, Nakatsukasa T, Htun PH, Thu M, Omori S, Okiji T. Effect of kinematics on the torque/force generation, surface characteristics, and shaping ability of a nickel titanium rotary glide path instrument: an ex-vivo study. Int Endod J 2022; 55:531-543. [PMID: 35263803 DOI: 10.1111/iej.13718] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/01/2022] [Accepted: 03/01/2022] [Indexed: 11/30/2022]
Abstract
AIM To evaluate the effect of various rotational motions on the torque/force generation, surface wear, and shaping ability of the ProGlider glide path instrument (Dentsply Sirona). METHODOLOGY Mesiobuccal and mesiolingual canals of mandibular molars were selected based on the canal volume, length, angle of curvature (25°-40°), and radius of curvature (4-8 mm) after micro-computed tomographic scanning. The samples were randomly assigned to four groups (n = 13, each) according to movement kinematics [continuous rotation (CR; 300 rpm), optimum torque reverse motion (OTR; 180° forward and 90° reverse when torque > 0.4 N·cm), time-dependent reciprocal motion (TmR; 180° forward and 90° reverse), and optimum glide path motion (OGP; a combination of 90° forward, 90° reverse, 90° forward, and 120° reverse)]. Instrumentation was performed with an automated root canal instrument and torque/force analysing device. Maximum torque/force values, canal volume changes, and canal-centring ratios at 1, 3, 5, and 7 mm were evaluated. Surface defects (pits, grooves, microcracks, blunt cutting edges, and disruption of cutting edges) and spiral distortion on the ProGlider instrument were scored at the tip and 5 mm short of the tip before and after five consecutive uses with scanning electron microscopy. The Kruskal-Wallis test followed by Dunn's post-test with Bonferroni correction and Wilcoxon signed-rank test were used to analyse the data (α = 0.05). RESULTS OGP generated significantly less clockwise torque and greater upward force than other groups (P < 0.05). OGP resulted in significantly fewer surface defects than CR (P < 0.05). In OGP and CR, the tip exhibited more surface defects than 5 mm short of the tip (P < 0.05). CR resulted in greater volume changes than OGP and TmR (P < 0.05) and greater centring ratios (i.e., more deviation) than OGP at 1 mm and OTR at 3 mm (P < 0.05). CONCLUSIONS Under laboratory conditions using the ProGlider instrument, OGP generated significantly less clockwise torque and greater upward force than the other rotatory motions. OGP generated fewer superficial defects than CR, and the three modes of reciprocal rotation better maintained the apical curvature of root canals than CR with the ProGlider instrument.
Collapse
Affiliation(s)
- M S Kyaw
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Department of Conservative Dentistry, University of Dental Medicine (Mandalay), Mandalay, Myanmar
| | - A Ebihara
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - K Maki
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - S Kimura
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - T Nakatsukasa
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - P H Htun
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - M Thu
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - S Omori
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - T Okiji
- Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| |
Collapse
|
4
|
Armagan S, Haznedaroglu F. Scanning electron microscopy analysis of conventional and controlled-memory nickel titanium files before and after multi-uses in root canals. Microsc Res Tech 2021; 84:1321-1327. [PMID: 33429461 DOI: 10.1002/jemt.23691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 11/11/2020] [Accepted: 12/20/2020] [Indexed: 11/07/2022]
Abstract
The current study aimed to examine changes in the physical properties of conventional and CM nickel-titanium instruments after repeated clinical use, disinfection-sterilization processes, using scanning electron microscopy (SEM). Sixty extracted mandibular molar mesial roots were used in this ex vivo study. The 60 teeth underwent final apical shaping (#25/.06) by the Revo-S SU (Revo-S Group: #25/.06; Micromega; n = 10) and Hyflex CM (Hyflex CM group: #25/.06; Coltene-Whaledent; n = 10) groups. One instrument of each group was used to shape six different teeth (Revo-S SU in 3 MB and 3 ML canals, and Hyflex CM in 3 MB and 3 ML canals), sequentially. The physical changes evident on the surfaces of the files after sequential use and sterilization processes were analyzed by SEM after the first, third, and sixth use. The first SEM examination was performed immediately after removal from the packages. Following first SEM examination, the files were sterilized before the first use as would be customary in practice. Qualitative evaluations were made by two evaluators, according to the following criteria: tip deformation, cutting edge deformation, debris, and microfracture. Revo-S showed a significant difference in cutting edge deformation, tip deformation, and microcrack formation, as compared to Hyflex CM. There was no significant difference between the groups in debris with the increasing number of uses. In this study, Hyflex CM (CM nickel-titanium) files showed better performance in terms of deformation and microcrack formation as the number of uses increased than did Revo-S (conventional nickel-titanium) files.
Collapse
Affiliation(s)
- Safa Armagan
- Department of Endodontics, Faculty of Dentistry, Istanbul Unıversity, Istanbul, Turkey
| | - Faruk Haznedaroglu
- Department of Endodontics, Faculty of Dentistry, Istanbul Unıversity, Istanbul, Turkey
| |
Collapse
|
5
|
Karamifar K, Samavi S, Saghiri MA. Topographic changes in NiTi rotary instruments after the clinical use. AUST ENDOD J 2020; 46:315-322. [PMID: 32748502 DOI: 10.1111/aej.12427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 06/05/2020] [Accepted: 07/06/2020] [Indexed: 11/28/2022]
Abstract
Surface alterations of instruments were investigated after single and multiple uses in the root canals. XP-endo Shaper (n = 5) and WaveOne GOLD (n = 5) files were used until the separation of the instruments occurred. The apical 3-mm and separated fragments were analysed by SEM to determine the changes in the instruments and the cross-sections of the separated fragments. Each group was divided into five subgroups: control, first, second, third and fourth molar. The results were reported descriptively for each group. In the XP-endo Shaper group, microcracks started to appear after the second use, and pitting and galvanic corrosion occurred after the third use. During the fourth use, microcracks propagated, resulting in ductile fracture while it happened after the third use in the second group. The single use of XP-endo Shaper and WaveOne GOLD was safe without any major changes on their surfaces. Reciprocating motion was not necessarily superior to full rotation motion.
Collapse
Affiliation(s)
- Kasra Karamifar
- Department of Endodontics, Dental School, Shiraz Azad University, Shiraz, Iran.,Sector of Angiogenesis Regenerative Medicine, Dr.Hajar Afsar Lajevardi Research Cluster (DHAL), Hackensack, NJ, USA.,Oral and Dental disease Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Sama Samavi
- Department of Endodontics, Dental School, Shiraz Azad University, Shiraz, Iran
| | - Mohammad Ali Saghiri
- Biomaterial and Prosthodontic Laboratory, Department of Restorative Dentistry, Rutgers School of Dental Medicine, Newark, NJ, USA
| |
Collapse
|
6
|
Bueno CRE, Cury MTS, Vasques AMV, Sivieri-Araújo G, Jacinto RC, Gomes-Filho JE, Cintra LTA, Dezan-Júnior E. Cyclic fatigue resistance of novel Genius and Edgefile nickel-titanium reciprocating instruments. Braz Oral Res 2019; 33:e028. [PMID: 30994706 DOI: 10.1590/1807-3107bor-2019.vol33.0028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 03/08/2019] [Indexed: 11/22/2022] Open
Abstract
This study aimed to assess the cyclic fatigue resistance of Genius and EdgeFile X1 reciprocating instruments compared with WaveOne Gold Primary. Twenty Genius (Ultradent) 25.04, 20 Genius 30.04, 20 EdgeFile X1 (EdgeEndo) and 20 WaveOne Gold Primary (Dentsply Maillefer) instruments were included in this study and tested in a static cyclic fatigue testing device, which has an artificial stainless steel canal with a 60° angle of curvature and a 5-mm radius of curvature. All instruments were operated in reciprocation mode until fracture occurred. The number of cycles to failure (NCF) was calculated and time to fracture (TF) was recorded in seconds using a digital chronometer. The mean and standard deviations of NCF and TF were calculated for each reciprocating system and the data were subjected to Kruskal-Wallis one-way analysis of variance and to Dunn's test (p < .05) using SigmaPlot software (Systat software, CA, USA). The fractured surfaces of five instruments from each brand were randomly examined and microphotographed by a low-vacuum environmental scanning electron microscopy - SEM (Tabletop Microscope TM3030, Hitachi, Japan) to confirm the cyclic fatigue fracture. EdgeFile exhibited the highest cyclic fatigue resistance, followed by both Genius files (p < .05). Within the limitations of this in vitro study, EdgeFile X1 instruments had significantly higher cyclic fatigue resistance than did Genius and WaveOne Gold Primary instruments. The cyclic fatigue resistance of both Genius files was higher than that of WaveOne Gold Primary.
Collapse
Affiliation(s)
| | - Marina Tolomei Sandoval Cury
- Universidade Estadual Paulista- UNESP, Araçatuba School of Dentistry, Department of Endodontics, Araçatuba, SP, Brazil
| | - Ana Maria Veiga Vasques
- Universidade Estadual Paulista- UNESP, Araçatuba School of Dentistry, Department of Endodontics, Araçatuba, SP, Brazil
| | - Gustavo Sivieri-Araújo
- Universidade Estadual Paulista- UNESP, Araçatuba School of Dentistry, Department of Endodontics, Araçatuba, SP, Brazil
| | - Rogério Castilho Jacinto
- Universidade Estadual Paulista- UNESP, Araçatuba School of Dentistry, Department of Endodontics, Araçatuba, SP, Brazil
| | - João Eduardo Gomes-Filho
- Universidade Estadual Paulista- UNESP, Araçatuba School of Dentistry, Department of Endodontics, Araçatuba, SP, Brazil
| | - Luciano Tavares Angelo Cintra
- Universidade Estadual Paulista- UNESP, Araçatuba School of Dentistry, Department of Endodontics, Araçatuba, SP, Brazil
| | - Eloi Dezan-Júnior
- Universidade Estadual Paulista- UNESP, Araçatuba School of Dentistry, Department of Endodontics, Araçatuba, SP, Brazil
| |
Collapse
|
7
|
Surface nanoscale profile of WaveOne, WaveOne Gold, Reciproc, and Reciproc blue, before and after root canal preparation. Odontology 2019; 107:500-506. [DOI: 10.1007/s10266-019-00424-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 03/19/2019] [Indexed: 10/27/2022]
|
8
|
Comparison of Alterations in the Surface Topographies of HyFlex CM and HyFlex EDM Nickel-titanium Files after Root Canal Preparation: A Three-dimensional Optical Profilometry Study. J Endod 2018; 44:115-119. [DOI: 10.1016/j.joen.2017.05.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/29/2017] [Accepted: 05/30/2017] [Indexed: 11/18/2022]
|
9
|
Qaed NA, Mourshed BD, Al-Shamiri HM, Alaizari N, Alhamdah SS. The Effect of surface topographical changes of two different surface treatments rotary instrument. J Clin Exp Dent 2018; 10:e49-e53. [PMID: 29670715 PMCID: PMC5899810 DOI: 10.4317/jced.54472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Accepted: 12/06/2017] [Indexed: 11/26/2022] Open
Abstract
Background One of the major innovations in endodontics has been the introduction of nickel-titanium (NiTi) alloy. This study evaluated the surface topographical changes of two different surface treatments rotary instrument after instrumentation and sterilization. Material and Methods 240 Extracted teeth were included in this study. 90 new AlphaKite and Revo-S NiTi rotary instruments were selected and divided into two groups (Group A 45 AlphaKite and group B 45 Revo-S). Each group were divided into three subgroups: (A1, B1) n=5 files were used as a control, (A2,B2) n=20 files were used to prepare three root canals using endodontic rotary motor then sterilized by autoclave for one cycle under 121°C at 15 psi for 30 minutes and (A3,B3) n=20 files were used to prepare nine root canals using the same rotary system then sterilized by autoclave for three cycles under 121°C at 15 psi for 30 minutes. Files were examined under scanning electron microscopy. Results On examining the AlphaKite, A1 revealed gross machining grooves on their surface with no pits, A2 showed disruption of cutting and A3 showed microcracks and deepening of the machining grooves. B1 showed a smoother surface with few machining grooves, B2 showed dulling and blunting of the cutting edges was predominant and B3 files showed plastic deformation in the form of unwinding of the flutes. Conclusions The defects were less distributed along the electropolished Revo-S files than the physical vapor deposition AlphaKite. Key words:Endodontic instruments, electropolished, rotary, sterilization.
Collapse
Affiliation(s)
- Nashwan-Ahmed Qaed
- BDS, MSc, Lecturer, Department of restorative Dentistry, Al-Farabi Colleges, Riyadh, Saudi Arabia
| | - Bilal-Diab Mourshed
- BDS, MSc, Lecturer, Department of Prosthetic Dental Sciences, Al-Farabi College for Dentistry and Nursing, Riyadh, Saudi Arabia; Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Kiel, Germany
| | - Hashem-Motahir Al-Shamiri
- BDS, MSc, Lecturer- Department of Oral and Maxillofacial Surgery, Al-Farabi Colleges, Riyadh, Saudi Arabia
| | - Nader Alaizari
- BDS, MSc, Lecturer, Department of Oral Medicine and Diagnostic Sciences, AlFarabi Colleges, Riyadh, Saudi Arabia
| | | |
Collapse
|
10
|
Türker SA, Sağlam BC, Koçak MM, Koçak S. The effect of glide path on the surface quality of new and used rotary and reciprocating single files: OneShape versus WaveOne. SCANNING 2014; 36:608-613. [PMID: 25185777 DOI: 10.1002/sca.21161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 07/21/2014] [Accepted: 08/01/2014] [Indexed: 06/03/2023]
Abstract
The aim of this study was to evaluate the effect of glide path preparation on the surface topography changes of WaveOne and OneShape single files using atomic force microscopy analysis. Two commercially available brands of single file systems were analyzed, including 15 specimens/brand as following: Group I; WaveOne 0.08/25 (Dentsply Maillefer, Ballaigues, Switzerland) and Group II; OneShape 0.06/25 (Micro Mega, Besançon, France). In each group, 3 new files were subjected to AFM analysis as received from manufacturer, and 12 files were analyzed after preparation of root canals. A total of 20 human maxillary molar teeth were selected. In each group, 12 files were divided into 4 subgroups according to instruments that were used in one or three root canals with or without a previous glide path (n = 3). After preparation the surface analysis of single files was performed on 11 different points located along a 3-mm section starting at the tip of each file using AFM. Root mean square (RMS) values were recorded to investigate the surface features of endodontic files. The differences between RMS values were tested by one-way ANOVA. There was no statistically significant difference between the groups (p > 0.05). Creation of a glide path did not affect the surface topography of single file systems.
Collapse
Affiliation(s)
- Sevinç Aktemur Türker
- Department of Endodontics, Faculty of Dentistry, Bülent Ecevit University, Zonguldak, Turkey
| | | | | | | |
Collapse
|
11
|
Caballero H, Rivera F, Salas H. Scanning electron microscopy of superficial defects in Twisted files and Reciproc nickel-titanium files after use in extracted molars. Int Endod J 2014; 48:229-35. [DOI: 10.1111/iej.12304] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 04/23/2014] [Indexed: 11/27/2022]
Affiliation(s)
- H. Caballero
- Department of Endodontics; School of Dentistry; Católica de Santa Maria University; Arequipa Peru
| | - F. Rivera
- Department of Endodontics; School of Dentistry; Católica de Santa Maria University; Arequipa Peru
| | - H. Salas
- Department of Endodontics; School of Dentistry; Católica de Santa Maria University; Arequipa Peru
| |
Collapse
|
12
|
Fatma Y, Ozgur U. Evaluation of surface topography changes in three NiTi file systems using rotary and reciprocal motion: An atomic force microscopy study. Microsc Res Tech 2013; 77:177-82. [PMID: 24375725 DOI: 10.1002/jemt.22325] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/05/2013] [Accepted: 12/07/2013] [Indexed: 11/06/2022]
Abstract
AIM To evaluate the surface topography changes in three nickel-titanium (NiTi) file systems using either rotary or reciprocal motion using atomic force microscopy (AFM), and to determine the effect of scanning area on the AFM results in this study. METHODOLOGY Five points on a F2 Protaper file, R25 Reciproc file, and a Primary file from WaveOne systems were scanned preoperatively in 1 × 1 and 5 × 5 µm(2) with an AFM device that can scan an intact (not sectioned) file. One standardized resin block was used for each instrument, according to the manufacturer's recommendations. Points were re-scanned postoperatively using the same AFM and settings. Root-mean-square (RMS) and roughness average (Ra) values were obtained. The preoperative and postoperative surface topographies were compared separately in terms of RMS and Ra values. The surface topography change scores were analyzed using Kruskal-Wallis and Mann-Whitney U tests using a 0.10 significance level. RESULTS There were no significant differences preoperatively among the NiTi file systems in 1 × 1 or 5 × 5 µm(2) areas. Postoperatively, the WaveOne Primary had more surface irregularities (significant for 5 × 5 µm(2) scan in Ra evaluation). CONCLUSIONS Three-dimensional AFM images of instrument surfaces showed topographic irregularities preoperatively and postoperatively. AFM results differ depending on the scanning area and file used.
Collapse
Affiliation(s)
- Yalpi Fatma
- Department of Endodontics, Faculty of Dentistry, University of Gazi, Ankara, Turkey
| | | |
Collapse
|
13
|
Fayyad DM, Mahran AH. Atomic force microscopic evaluation of nanostructure alterations of rotary NiTi instruments after immersion in irrigating solutions. Int Endod J 2013; 47:567-73. [DOI: 10.1111/iej.12189] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 08/31/2013] [Indexed: 11/29/2022]
Affiliation(s)
- D. M. Fayyad
- Department of Endodontics; Faculty of Dentistry; Suez Canal University; Ismailia Egypt
| | - A. H. Mahran
- Department of Endodontics; Faculty of Dentistry; Ain Shams University; Cairo Egypt
| |
Collapse
|
14
|
Zarei M, Javidi M, Erfanian M, Lomee M, Afkhami F. Comparison of air-driven vs electric torque control motors on canal centering ability by ProTaper NiTi rotary instruments. J Contemp Dent Pract 2013; 14:71-75. [PMID: 23579897 DOI: 10.5005/jp-journals-10024-1273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
AIM Cleaning and shaping is one of the most important phases in root canal therapy. Various rotary NiTi systems minimize accidents and facilitate the shaping process. Todays NiTi files are used with air-driven and electric handpieces. This study compared the canal centering after instrumentation using the ProTaper system using Endo IT, electric torque-control motor, and NSK air-driven handpiece. MATERIALS AND METHODS This ex vivo randomized controlled trial study involved 26 mesial mandibular root canals with 10 to 35° curvature. The roots were randomly divided into 2 groups of 13 canals each. The roots were mounted in an endodontic cube with acrylic resin, sectioned horizontally at 2, 6 and 10 mm from the apex and then reassembled. The canals were instrumented according to the manufacturer's instructions using ProTaper rotary files and electric torque-control motors (group 1) or air-driven handpieces (group 2). Photographs of the cross-sections included shots before and after instrumentation, and image analysis was performed using Photoshop software. The centering ability and canal transportation was also evaluated. Repeated measurement and independent t-test provided statistical analysis of canal transportation. RESULTS The comparison of the rate of transportation toward internal or external walls between the two groups was not statistically significant (p = 0.62). Comparison of the rate of transportation of sections within one group was not significant (p = 0.28). CONCLUSION Use of rotary NiTi file with either electric torquecontrol motor or air-driven handpiece had no effect on canal centering. CLINICAL SIGNIFICANCE NiTi rotary instruments can be used with air-driven motors without any considerable changes in root canal anatomy, however it needs the clinician to be expert.
Collapse
Affiliation(s)
- Mina Zarei
- Department of Endodontics, Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | | | | | | |
Collapse
|
15
|
Subha N, Sikri VK. Comparative evaluation of surface changes in four Ni-Ti instruments with successive uses - An SEM study. J Conserv Dent 2011; 14:282-6. [PMID: 22025834 PMCID: PMC3198560 DOI: 10.4103/0972-0707.85817] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 12/28/2010] [Accepted: 02/19/2011] [Indexed: 11/04/2022] Open
Abstract
AIM To evaluate the surface alterations seen in four kinds of Nickel-Titanium (Ni-Ti) instruments using a scanning electron microscope (SEM) for five successive uses in preparing root canals of extracted human molars and also to determine whether the design of the instrument influenced the appearance of defects on the instrument surface. MATERIALS AND METHODS Four different types of instruments namely; ProFile, ProTaper Rotary, ProTaper Hand and K3 Endo were used in 300 mesio-buccal canals. The instruments were examined under the SEM, after every use, to assess the progress of changes on their surfaces for a maximum of five uses. STATISTICAL ANALYSIS USED Chi-square test. RESULTS The most prevalent defects observed were pitting, followed by metal strips. Signs of discontinuity, microfractures and disruption of cutting edge were also evident. Number of defects increased with successive uses. CONCLUSIONS ProTaper Hand showed significantly more microfractures and metal strips than other instruments from third use onwards. ProTaper Rotary and K3 Endo also showed significant changes.
Collapse
Affiliation(s)
- N Subha
- Departments of Conservative Dentistry and Endodontics, Sri Ramakrishna Dental College and Hospital, Coimbatore, Tamil Nadu, India
| | | |
Collapse
|
16
|
Kosti E, Zinelis S, Molyvdas I, Lambrianidis T. Effect of root canal curvature on the failure incidence of ProFile rotary Ni-Ti endodontic instruments. Int Endod J 2011; 44:917-25. [DOI: 10.1111/j.1365-2591.2011.01900.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
17
|
Ametrano G, D’Antò V, Di Caprio MP, Simeone M, Rengo S, Spagnuolo G. Effects of sodium hypochlorite and ethylenediaminetetraacetic acid on rotary nickel-titanium instruments evaluated using atomic force microscopy. Int Endod J 2010; 44:203-9. [DOI: 10.1111/j.1365-2591.2010.01799.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
18
|
Condorelli GG, Bonaccorso A, Smecca E, Schäfer E, Cantatore G, Tripi TR. Improvement of the fatigue resistance of NiTi endodontic files by surface and bulk modifications. Int Endod J 2010; 43:866-73. [DOI: 10.1111/j.1365-2591.2010.01759.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|
19
|
Inan U, Gonulol N. Deformation and Fracture of Mtwo Rotary Nickel-Titanium Instruments After Clinical Use. J Endod 2009; 35:1396-9. [DOI: 10.1016/j.joen.2009.06.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 06/16/2009] [Accepted: 06/22/2009] [Indexed: 10/20/2022]
|
20
|
Bonaccorso A, Cantatore G, Condorelli GG, Schäfer E, Tripi TR. Shaping ability of four nickel-titanium rotary instruments in simulated S-shaped canals. J Endod 2009; 35:883-6. [PMID: 19482191 DOI: 10.1016/j.joen.2009.03.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2009] [Revised: 02/20/2009] [Accepted: 03/02/2009] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The purpose of this study was to compare the shaping ability of ProTaper, Mtwo, BioRaCe, and BioRaCe + S-Apex instruments in simulated canals with an S-shaped curvature. METHODS Canal transportation and aberrations were assessed by comparing the preinstrumentation and postinstrumentation images under a stereomicroscope. Analysis of variance and post hoc Student-Newman-Keuls test were used for statistical analysis. RESULTS ProTaper instruments caused more pronounced canal transportation in the apical curvature (P < .01) than all other instruments. The use of ProTaper, Mtwo, and BioRaCe instruments resulted in more canal aberrations compared with BioRaCe + S-Apex (P < .05). CONCLUSIONS NiTi systems including less tapered and more flexible instruments like S-Apex seem to be favorable when preparing S-shaped canals.
Collapse
|
21
|
Chianello G, Specian VL, Hardt LCF, Raldi DP, Lage-Marques JL, Habitante SM. Surface finishing of unused rotary endodontic instruments: a SEM study. Braz Dent J 2009; 19:109-13. [PMID: 18568223 DOI: 10.1590/s0103-64402008000200004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During endodontic therapy, cleaning of root canals is performed using endodontic files and auxiliary chemical substances, and it is important that the endodontist be familiar with the instruments used in daily practice. This study evaluated, under scanning electron microscopy (SEM), the quality of the surface finishing of unused rotary endodontic instruments. Fifty sizes 20, 25 and 30 rotary files from different commercial brands (ProFile, Protaper, Race, Hero and K3 Endo) were removed directly from their packages and had their final 3 mm examined with a scanning electron microscope at x190 magnification with no previous preparation. The images were evaluated by 3 skillful, calibrated, blinded observers according to the following criteria: cutting edge, debris, grooves, microcavities, tip shape, tip position, scraping and transition angle. Data were recorded in worksheets designed for the study. Irregular edges were observed in 50-100% of the files. Except for ProFile, all commercial brands presented surface debris in 100% of samples. Only Race files showed no grooves or microcavities. K3 Endo files presented the best tip centralization. Excetp for ProTaper files, all commercial brands presented blunt-cutting edges in 100% of samples. All types of files presented surface scraping. K3 Endo files and Protaper had a high percentage of transition angle. Based on the evaluation criteria used in the present study, most samples presented a minimum of 2 alterations and a maximum of 7 alterations per instrument. Under the tested conditions, the quality of the surface finishing of the examined instruments was not as expected, given that no instrument was free of imperfections and most of them presented at least 2 and up to 7 types of surface defects. These results suggest that the manufacturing process and the packaging conditions of rotary endodontic instruments are far from ideal.
Collapse
|
22
|
Chemical Analysis of Nickel-Titanium Rotary Instruments with and without Electropolishing after Cleaning Procedures with Sodium Hypochlorite. J Endod 2008; 34:1391-1395. [DOI: 10.1016/j.joen.2008.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 07/31/2008] [Accepted: 08/02/2008] [Indexed: 11/18/2022]
|
23
|
Structural effects of sodium hypochlorite solution on RaCe rotary nickel-titanium instruments: an atomic force microscopy study. ACTA ACUST UNITED AC 2008; 105:661-5. [DOI: 10.1016/j.tripleo.2007.11.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 10/29/2007] [Accepted: 11/05/2007] [Indexed: 11/23/2022]
|
24
|
Vieira EP, França EC, Martins RC, Buono VTL, Bahia MGA. Influence of multiple clinical use on fatigue resistance of ProTaper rotary nickel-titanium instruments. Int Endod J 2007; 41:163-72. [PMID: 18005043 DOI: 10.1111/j.1365-2591.2007.01336.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To examine the influence of clinical use on the occurrence of deformation and fracture and on the fatigue resistance of ProTaper rotary instruments. METHODOLOGY Root canal treatments were performed on patients using the ProTaper rotary system. Ten sets of instruments were used by an experienced endodontist, each set in five molars. Another 10 sets of instruments were used by the same operator, each set in eight molars. In addition, 10 sets of instruments were used, each set in five molars, by undergraduate students with no clinical experience with the system. After clinical use, S1, S2, F1 and F2 instruments were analysed for damage by optical and scanning electron microscopy. The used sets, along with a control group of 12 sets of new instruments, were then tested in a bench device for fatigue resistance. RESULTS The use of the ProTaper rotary instruments by an experienced endodontist allowed for the cleaning and shaping of the root canal system of up to eight molars without fracture. During the students work, six instruments fractured. Fatigue resistance decreased upon clinical use for all instruments analysed. CONCLUSIONS Fatigue resistance of used instruments was reduced, but no significant change was observed amongst the instruments used for shaping the canals of five and eight molars. Operator experience affected the occurrence of fracture and plastic deformation during shaping.
Collapse
Affiliation(s)
- E P Vieira
- Department of Restoration Dentistry, Faculty of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | | | | | | |
Collapse
|
25
|
Inan U, Aydin C, Uzun O, Topuz O, Alacam T. Evaluation of the Surface Characteristics of Used and New ProTaper Instruments: An Atomic Force Microscopy Study. J Endod 2007; 33:1334-7. [DOI: 10.1016/j.joen.2007.07.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 06/28/2007] [Accepted: 07/15/2007] [Indexed: 11/25/2022]
|
26
|
Anderson ME, Price JWH, Parashos P. Fracture resistance of electropolished rotary nickel-titanium endodontic instruments. J Endod 2007; 33:1212-6. [PMID: 17889692 DOI: 10.1016/j.joen.2007.07.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 06/27/2007] [Accepted: 07/01/2007] [Indexed: 10/22/2022]
Abstract
The purpose of this study was to investigate the effect of electropolishing on cyclic flexural fatigue and torsional strength of rotary nickel-titanium endodontic instruments. Electropolished and nonelectropolished ISO size 30 (0.04 taper) EndoWave (J Morita Corporation, Osaka, Japan), ProFile (Dentsply Maillefer, Ballaigues, Switzerland), and RaCe (FKG, La-Chaux De Fonds, Switzerland) instruments from the same manufacturing batches were investigated. The number of rotations to fracture and torque at fracture were determined and compared among the instruments tested. Instruments were viewed under a scanning electron microscope (SEM) to assess the degree and quality of electropolishing. Overall, electropolished instruments performed significantly better than nonelectropolished instruments in cyclic fatigue testing and, to a lesser extent, in static torsional loading. When viewing electropolished instruments with the SEM, milling grooves, cracks, pits, and areas of metal rollover were observed, although they were more evident in the nonelectropolished instruments. Electropolishing may have beneficial effects in prolonging the fatigue life of rotary NiTi endodontic instruments. The benefits of electropolishing are likely to be caused by a reduction in surface irregularities that serve as points for stress concentration and crack initiation.
Collapse
Affiliation(s)
- Margot E Anderson
- School of Dental Science, University of Melbourne, Melbourne, Australia
| | | | | |
Collapse
|
27
|
Abstract
BACKGROUND and Overview. With the increased use of nickel-titanium (NiTi) rotary instruments for root canal preparation in endodontics, instrument fracture has become more prevalent. Extensive research has been conducted on the physical properties and mechanical characteristics of NiTi rotary instruments, as well as the factors that can contribute to instrument failure. NiTi rotary instruments are subjected to torque and are susceptible to cyclic fatigue, which are the main causes of instrument fracture. However, with an understanding of how these instruments function in preparing root canals and by applying ways to reduce torque-generated metal fatigue, clinicians can use the instruments safely in clinical practice. RESULTS The author presents 12 measures that clinicians can take to prevent NiTi rotary instrument fracture and discusses them in detail. CLINICAL IMPLICATIONS NiTi rotary instrument fracture complicates the progress, and compromises the prognosis of endodontic treatment. However, when clinicians take appropriate measures, rotary instrument fractures can be prevented.
Collapse
Affiliation(s)
- Peter M Di Fiore
- Predoctoral Endodontics, New York University, College of Dentistry, Department of Endodontics, New York, NY 10010, USA
| |
Collapse
|
28
|
Parashos P, Messer HH. Rotary NiTi Instrument Fracture and its Consequences. J Endod 2006; 32:1031-43. [PMID: 17055902 DOI: 10.1016/j.joen.2006.06.008] [Citation(s) in RCA: 309] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2006] [Revised: 06/08/2006] [Accepted: 06/08/2006] [Indexed: 11/26/2022]
Abstract
The fracture of endodontic instruments is a procedural problem creating a major obstacle to normally routine therapy. With the advent of rotary nickel-titanium (NiTi) instruments this issue seems to have assumed such prominence as to be a considerable hindrance to the adoption of this major technical advancement. Considerable research has been undertaken to understand the mechanisms of failure of NiTi alloy to minimize its occurrence. This has led to changes in instrument design, instrumentation protocols, and manufacturing methods. In addition, factors related to clinician experience, technique, and competence have been shown to be influential. From an assessment of the literature presented, we derive clinical recommendations concerning prevention and management of this complication.
Collapse
Affiliation(s)
- Peter Parashos
- School of Dental Science, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia.
| | | |
Collapse
|
29
|
Di Fiore PM, Genov KA, Komaroff E, Li Y, Lin L. Nickel-titanium rotary instrument fracture: a clinical practice assessment. Int Endod J 2006; 39:700-8. [PMID: 16916359 DOI: 10.1111/j.1365-2591.2006.01137.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To prospectively determine the incidence of nickel-titanium rotary instrument fracture in an endodontic clinical practice setting. METHODOLOGY Eleven second year endodontic residents, using four nickel-titanium rotary instrument systems (ProFile, ProTaper, GTRotary and K3Endo) according to the recommendations of the manufacturers, instrumented 3181 canals in 1403 teeth of 1235 patients, in a dental school post-graduate endodontic clinic, in 1 year. The incidence of instrument fracture was determined based on the number of instruments used. When fracture occurred, data were collected concerning the type, size, taper and prior use of the fractured instruments, the length and location of the fragment within the root canal and the curvature of the canal. RESULTS The overall incidence of instrument fracture was 0.39%. The incidence of fracture for ProFile, ProTaper, GTRotary and K3Endo files was 0.28%, 0.41%, 0.39% and 0.52%, respectively. There was no statistically significant difference between instrument systems. The percentage of teeth in which instruments fractured was 1.9% (0.28% for anterior teeth, 1.56% for pre-molars and 2.74% for molars). A total of 26 instruments fractured, of which 23 had tapers of 0.06 or greater. Most of the fragments were located in the apical third of the root canal, and both the median and mode amongst the fragment lengths were 2 mm. CONCLUSIONS The low incidence of nickel-titanium rotary instrument fracture supports the continued use of these instruments in root canal treatment.
Collapse
Affiliation(s)
- P M Di Fiore
- Department of Endodontics, New York University, College of Dentistry, NY 10010, USA.
| | | | | | | | | |
Collapse
|
30
|
Abstract
Atomic force microscopy (AFM) is a well established and documented tool for materials investigation. The aim of this study was to evaluate the topography of conventional stainless-steel files and both hand and rotary nickel-titanium (NiTi) files by using AFM. One endodontic file of each of the following was selected: stainless-steel K-file Dentsply, stainless-steel K-file Moyco, hand NiTi K-file Nitiflex, hand NiTi Greater Taper, rotary NiTi Greater Taper, and rotary NiTi Quantec. The analyses were performed on twenty different points located along a 3-mm section starting at the tip of each file. Root mean square (RMS) parameters for contact mode imaging microscopy variations were measured. The differences between RMS values were tested by ANOVA with Fisher's protected LSD test for multiple comparisons (p < 0.05). RMS of depth profile data was used to determine any statistically significant difference in vertical amplitude. According to results, all instruments showed topographic irregularities distributed on surface. Endodontic files manufactured by the same method and alloy demonstrated significant differences, whereas no significant differences were found for instruments produced by different alloys and methods (p < 0.05). The hand NiTi Greater Taper, rotary NiTi Greater Taper, and rotary NiTi Quantec showed greater values of vertical amplitude topography compared to K-Dentsply and Nitiflex files (p < 0.05). The AFM technique proved to be a valuable research tool in the investigation of endodontic files topography.
Collapse
Affiliation(s)
- Caroline R A Valois
- Department of Genetics and Morphology, Institute of Biology, University of Brasilia, Brasília, Brazil
| | | | | |
Collapse
|
31
|
Peng B, Shen Y, Cheung GSP, Xia TJ. Defects in ProTaper S1 instruments after clinical use: longitudinal examination. Int Endod J 2005; 38:550-7. [PMID: 16011774 DOI: 10.1111/j.1365-2591.2005.00991.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To evaluate defects in ProTaper shaping instrument S1 after a defined schedule of clinical use. METHODOLOGY Among all ProTaper files discarded from an endodontic clinic at a stomatological school in China over a period of 17 months, 122 S1 instruments were collected. They were ultrasonically cleaned, autoclaved and then examined in the laboratory. Any instrument separation was noted; the average length involved was determined. The 0.5 mm region on either side of this length of discarded but intact instruments was examined circumferentially by scanning electron microscope. The region adjacent to the broken end of the fractured instruments was also examined in the same way. RESULTS One specimen was lost during processing. Of the remaining 121 instruments, 27 were separated with a mean fracture length of 3.67 mm from the tip. Of these, two files showed macroscopically torsional fracture and the others showed signs of flexural fatigue. Only one file that had not fractured showed visible unwinding defects. Examination of the 3.1-4.1 mm region of other unfractured instruments revealed the presence of microcracks, surface debris, pitting and/or wear of their cutting edges. Some debris particles seemed to have been trapped in crack-like structures. CONCLUSIONS Multiple use of ProTaper S1 pre-disposed the instrument to microcrack formation and wear of the cutting edges. There was a low prevalence of plastic deformation and most ProTaper S1 instruments failed without discernible sign of unwinding of the flutes. Further studies should address the mode of failure and the role of debris particles in the fracture mechanism.
Collapse
Affiliation(s)
- B Peng
- Key Laboratory for Oral Biomedical Engineering of the Ministry of Education, School of Stomatology, Wuhan University, Wuhan, China
| | | | | | | |
Collapse
|
32
|
Alapati SB, Brantley WA, Svec TA, Powers JM, Nusstein JM, Daehn GS. SEM observations of nickel-titanium rotary endodontic instruments that fractured during clinical Use. J Endod 2005; 31:40-3. [PMID: 15614004 DOI: 10.1097/01.don.0000132301.87637.4a] [Citation(s) in RCA: 180] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Numerous discarded ProFile GT, ProFile, and ProTaper nickel-titanium rotary instruments obtained from two graduate endodontic clinics were examined by scanning electron microscopy. These instruments had an unknown history of clinical use and had fractured or experienced considerable permanent torsional deformation without complete separation. The failure processes generally exhibited substantial ductile character, evidenced by a dimpled rupture fracture surface. Crack propagation at grain boundaries and cleavage surfaces indicative of transgranular fracture were observed for some specimens. It appeared that oxide particles from the manufacturing process served as nucleating sites for the microvoids, leading to dimpled rupture. A previously unreported fracture mode also was observed, in which crack propagation, approximately parallel to the local flute orientation, connected pitted regions on the surface. Combining present and previous scanning electron microscopy observations of clinically failed instruments, suggestions are offered for improving their fracture resistance.
Collapse
Affiliation(s)
- Satish B Alapati
- Section of Oral Biology, College of Dentistry, The Ohio State University, Columbus, OH 43218-2357, USA
| | | | | | | | | | | |
Collapse
|
33
|
Alapati SB, Brantley WA, Svec TA, Powers JM, Nusstein JM, Daehn GS. Proposed Role of Embedded Dentin Chips for the Clinical Failure of Nickel-Titanium Rotary Instruments. J Endod 2004; 30:339-41. [PMID: 15107646 DOI: 10.1097/00004770-200405000-00008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Discarded ProFile and ProTaper nickel-titanium rotary instruments, with unknown history of clinical use, were obtained from graduate endodontic clinics at Ohio State University and University of Texas Health Science Center at Houston Dental Branch. These discarded instruments and as-received instruments of both types were examined with a scanning electron microscope to investigate effects of clinical use and causes of failure. For used ProTaper instruments, dentinal debris was wedged mostly in narrow, radial, land-type regions and less on convex flute surfaces. For used ProFile instruments, dentinal debris was wedged mostly in the metal rollover and on concave flute surfaces. Used instruments of both types exhibited widened machining grooves, and elongated and stretched roll-over. Dentin chips were wedged in surface micro-cracks that appeared to propagate from original machining flaws and widen during in vivo root canal preparation. From our observational study, wedged dentinal deposits seem to play a pivotal role for clinical failure of these instruments.
Collapse
Affiliation(s)
- Satish B Alapati
- Dental Materials Science Program, College of Dentistry, The Ohio State University, Columbus, OH 43218-2357, USA
| | | | | | | | | | | |
Collapse
|
34
|
Alapati SB, Brantley WA, Svec TA, Powers JM, Mitchell JC. Scanning electron microscope observations of new and used nickel-titanium rotary files. J Endod 2003; 29:667-9. [PMID: 14606793 DOI: 10.1097/00004770-200310000-00014] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The appearances of the tip sections of ProFile 0.04 taper and Lightspeed 25-mm long, ISO size 25, nickel-titanium rotary instruments were compared with a scanning electron microscope in the as-received condition and after one, three, and six simulated clinical uses to prepare mesial canals of extracted mandibular molars. For the used ProFile instruments, there was some flattening of the characteristic material rollover and minor apparent wear at the edges of the flutes, but there was little change in the tip regions of the used Lightspeed instruments. Deposits on the surfaces of the instruments were attributed to the manufacturing processes and the in vitro preparation of root canals in the extracted teeth. The simulated clinical use did not cause substantial changes in the regions of these two brands of rotary instruments that are involved in the clinical preparation of root canals.
Collapse
Affiliation(s)
- Satish B Alapati
- Dental Materials Science Program, Prosthodontics and Endodontics, College of Dentistry, The Ohio State University, Columbus 4328-2357, USA
| | | | | | | | | |
Collapse
|