Abstract：
INTRODUCTION:The purpose of this study was to visualize the stresses and strain distribution patterns in ProTaper Universal F2 files (Dentsply Maillefer, Ballaigues, Switzerland) and to establish the stress- and strain-curvature relationship for this instrument under various conditions by using a dynamic, three-dimensional finite-element model. METHODS:An accurate geometric model of a ProTaper Universal F2 instrument was created. Two short, straight tubes were also modeled to represent the parts of root canal apical and coronal to the curvature. Then, the file was constrained to a curve of varying degree, curve length, and position. The maximum von Mises stress and strain on the tension side of the instrument was measured at 5-degree intervals in a numerical simulation package (LS-DYNA; Livermore Software Technology, Livermore, CA). RESULTS:The mechanical performance of the ProTaper F2 file under various conditions was simulated. A long curvature length produced lower values of stress and strain under the same angle of curvature. An increase in the curvature angle generally induces higher stress and strain. For the same degree and curve length, the stress and strain increased if the curved portion was situated further up the shaft of the instrument (ie, with a larger diameter). CONCLUSIONS:The dynamic, numerical model may be used to evaluate and compare the effect of various root canal curvatures on the behavior of different designs of root canal instrument. The magnitude of stress and strain imposed on the instrument is influenced by the abruptness and degree of curvature as well as the location of the curved portion.
journal_name
J Endodjournal_title
Journal of endodonticsauthors
Gao Y,Cheung GS,Shen Y,Zhou Xdoi
10.1016/j.joen.2011.06.003subject
Has Abstractpub_date
2011-10-01 00:00:00pages
1446-50issue
10eissn
0099-2399issn
1878-3554pii
S0099-2399(11)00706-0journal_volume
37pub_type
杂志文章abstract：:A case is presented in which a previous partial root canal treatment on a mandibular molar developed internal resorption of the distal canal. The case was followed at the University of Oklahoma student clinic and endodontic treatment completed in the mesial canals, with calcium hydroxide placed in the distal canal for...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200107000-00010
更新日期：2001-07-01 00:00:00
abstract：:The purpose of this study was to evaluate the integrity of resected root-end surfaces of extracted human teeth after using ultrasonic tips at low or high frequencies for root-end preparation. Thirty bilaterally matched pairs of single-rooted human teeth had root-end resections using a low-speed diamond saw and were ex...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(96)80091-4
更新日期：1996-04-01 00:00:00
abstract：:The apical sealing ability of amalgam, cold-burnished gutta-percha, amalgam with cavity varnish, and SuperEBA cement was evaluated in extracted human teeth. For each experimental group, the roots of 20 single-rooted teeth were sectioned from their crowns. Canals were cleaned, shaped, and obturated with vertically cond...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(89)80132-3
更新日期：1989-03-01 00:00:00
abstract：:The biocompatibility and apical microleakage of tricalcium phosphate based Sankin Apatite (SA) Type I, II, and III root canal sealers were investigated. Teflon tubes containing freshly mixed test materials were implanted in the subcutaneous tissue of mice. The observation periods were 24 h, 7, and 30 days, after which...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/s0099-2399(97)80255-5
更新日期：1997-02-01 00:00:00
abstract：INTRODUCTION:Outcome studies of endodontic treatment of necrotic immature permanent teeth rely on radiographic measures as surrogates of whether the treatment achieved regeneration/revascularization/revitalization. An increase in radiographic root length and/or width is thought to result in a better long-term prognosis...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2013.09.025
更新日期：2014-01-01 00:00:00
abstract：INTRODUCTION:The purpose of this article was to compare the cyclic fatigue resistance of Reciproc and Reciproc Blue files (VDW GmbH, Munich, Germany) that were used to prepare root canals of mandibular molar teeth with or without a glide path. METHODS:Sixty Reciproc R25 and 60 Reciproc Blue R25 files were used. The Re...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2018.03.004
更新日期：2018-06-01 00:00:00
abstract：:The purpose of treating furcal perforation is to seal the artificial communication between the endodontic space and the periradicular tissue to prevent alveolar bone resorption and damage to the periodontal ligament. These complications are not infrequent in cases of furcal and/or old perforations, which show a worse ...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2008.05.019
更新日期：2008-09-01 00:00:00
abstract：:Hepatocyte growth factor (HGF) is a potent mitogenic and angiogenic factor involved in the development of many tissues including the teeth. We previously reported that dental pulp cells express the HGF receptor c-met and that HGF can enhance cell proliferation and differentiation. The purpose of this study was to dete...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2008.11.031
更新日期：2009-03-01 00:00:00
abstract：:Irreversibly inflamed pulp (IIP) constitutes both a pathophysiologic and a diagnostic challenge. Gingival crevicular fluid (GCF) samples were obtained with Periopaper strips from IIP and adjacent and contralateral teeth for interleukin-8 (CXCL8) and tumor necrosis factor-alpha (TNF-alpha) measurements. Pain intensity ...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2007.10.022
更新日期：2008-02-01 00:00:00
abstract：INTRODUCTION:Autotransplantation is a viable option for treating missing teeth when a donor tooth is available. This retrospective study reports the success rate for the autotransplantation of 19 molars with complete root formation. METHODS:The study enrolled 19 patients (11 men and 8 women) in whom 19 molars were tra...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2010.04.028
更新日期：2010-08-01 00:00:00
abstract：:The aim of this study was to evaluate and compare the quantitative and qualitative inflammatory responses and bone formation potential after implantation of polyethylene tubes filled with a new calcium hydroxide containing sealer (MBPc) and ProRoot mineral trioxide aggregate (MTA). There were 48 Wistar rats divided in...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2005.07.007
更新日期：2006-06-01 00:00:00
abstract：:Cyclooxygenase-2 (COX-2) is induced after the activation of cells by a variety of proinflammatory agents. Recently, evidence has shown that COX-2 may play a role in the pathogenesis of pulpal inflammation. However, little is known regarding the mechanism of pulpal inflammation at the site of bacterial infection. The p...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200304000-00002
更新日期：2003-04-01 00:00:00
abstract：:Patients with odontogenic cutaneous sinus tracts usually seek treatment from a physician instead of a dentist and the etiology is frequently misdiagnosed. This case report describes a patient who sought treatment from a dentist because of a history of a previous cutaneous swelling on the ipsilateral side of his cheek....
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/s0099-2399(06)80959-3
更新日期：1992-06-01 00:00:00
abstract：INTRODUCTION:The aim of this study was to introduce an innovative method for autotransplantation of teeth using 3-dimensional (3D) surgical templates for guided osteotomy preparation and donor tooth placement. METHODS:This report describes autotransplantation of immature premolars as treatment of an 11-year-old boy ha...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2016.08.021
更新日期：2016-12-01 00:00:00
abstract：:The purpose of the study was to evaluate the biocompatibility of two current adhesive resins and a calcium hydroxide cement. Fifty-four polyethylene tubes were filled with these dental materials, which were hand-mixed or light-cured according to the manufacturer's directions: group 1--Clearfill Liner Bond 2 (Kuraray);...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200009000-00006
更新日期：2000-09-01 00:00:00
abstract：:The cytotoxicity of four different calcium hydroxide-based root canal sealers (Sealapex, Apexit, CRCS, and Endoflas FS) was tested using human gingiva fibroblasts. The fibroblasts were acquired from the attached gingiva of apparently healthy patients. The sealers were allowed to set for 24 and 48 h before being covere...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(06)81309-9
更新日期：1992-03-01 00:00:00
abstract：:A case is presented in which endodontic treatment of a maxillary lateral incisor with a talon cusp and two root canals failed following a mistaken diagnosis. What was first diagnosed as an endodontic lesion was, in all probability, a primary periodontal lesion caused by the advance of bacteria from the gingival crevic...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(06)81947-3
更新日期：1990-07-01 00:00:00
abstract：:The occurrence of Enterococcus faecalis in root canals of previously root filled teeth with apical periodontitis requiring retreatment was studied in Lithuanian patients. Twenty-five asymptomatic teeth were included in the study. Avoiding contamination microbiological samples were taken from the canals before and afte...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200010000-00004
更新日期：2000-10-01 00:00:00
abstract：INTRODUCTION:Compelling evidence pinpoints that pulp tissue engineering after the transplantation of stem cells is possible. Although intriguing, severe problems regarding clinical feasibility remain. Cell homing has been proposed as a viable alternative in which dentin-derived growth factors in a conducive scaffold ma...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2018.02.011
更新日期：2018-06-01 00:00:00
abstract：:When dentin is planed by endodontic instruments, a smear layer forms. Whether this layer should be removed is unknown and controversial. This study was conducted to assess the effect of the smear layer on retention of bacteria using an in vitro root canal bacterial colonization model. Canals of 26 extracted human cani...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(06)81186-6
更新日期：1994-02-01 00:00:00
abstract：:Increased levels of interleukin-1 (IL)-1, tumor necrosis factor-alpha (TNF-alpha), IL-6, and prostaglandin E2 (PGE2) have been detected in inflamed pulp tissue. To gain further insight into the molecular pathogenesis of pulpitis, we investigated the effects of IL-1alpha or TNF-alpha and PGE2, either alone or in combin...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200203000-00013
更新日期：2002-03-01 00:00:00
abstract：INTRODUCTION:The management of endodontic emergencies has been particularly challenging during the coronavirus disease 2019 (COVID-19) outbreak because of the possible generation of airborne particles and aerosols. The aim of this report was to contribute to the practice of endodontics by proposing a general protocol f...
journal_title：Journal of endodontics
pub_type： 杂志文章,评审
doi：10.1016/j.joen.2020.09.018
更新日期：2021-01-01 00:00:00
abstract：:This study investigated the possibility of saliva recontamination occurring between the root canal wall and sealer through dentinal tubules exposed after the cementum was removed at the cervical level by root planing and treatment with citric acid. Thirty-four extracted human maxillary anterior teeth were randomly pla...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(96)80024-0
更新日期：1996-11-01 00:00:00
abstract：INTRODUCTION:The purpose of this study was to compare the accuracy in vivo of 2 electronic apex locators (EALs), the Raypex 5 and the Mini Apex Locator. METHODS:The working length (WL) was determined electronically for 40 human root canals by using a K-file and 1 of the 2 EALs. The files were fixed at the WL, and the ...
journal_title：Journal of endodontics
pub_type： 杂志文章,随机对照试验
doi：10.1016/j.joen.2011.06.021
更新日期：2011-10-01 00:00:00
abstract：:This report presents an unusual indication for root resection of a lower molar tooth and also reviews the history of root resection. ...
journal_title：Journal of endodontics
pub_type： 杂志文章,评审
doi：10.1097/00004770-200004000-00016
更新日期：2000-04-01 00:00:00
abstract：INTRODUCTION:The purpose of this study was to compare the accuracy of the Root ZX II Apex Locator (RZX), the Elements Apex Locator (ELE), and the Precision Apex Locator (PAL). METHODS:Forty single-rooted extracted teeth were decoronated and the root canals coronally flared. Actual canal lengths were determined by inse...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2009.09.016
更新日期：2010-02-01 00:00:00
abstract：INTRODUCTION:Issues pertaining to the effective elimination of bacterial biofilm and disruption of biofilm structure still remains in endodontic disinfection. Nanoparticulates such as chitosan (CS-np) and zinc oxide (ZnO-np) are known to possess significant antibacterial properties. This study aimed to test (1) the eff...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2010.02.008
更新日期：2010-06-01 00:00:00
abstract：INTRODUCTION:A 3-antibiotic combination (3Mix) has been widely used in regenerative endodontics. Recent studies recommend that a safe concentration of 3Mix is in the range of 0.39 μg/mL and 1 mg/mL because higher concentrations may limit tissue regeneration. The aim of this study was to determine the regenerative capac...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2013.09.027
更新日期：2014-03-01 00:00:00
abstract：INTRODUCTION:The aim of the present study was to assess the bond strength of root fillings in oval-shaped canals prepared with the self-adjusting file (SAF) system. METHODS:A careful specimen selection resulted in 2 equal groups, each consisting of 12 extracted mandibular canines with oval canals that had vital pulps ...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2012.10.026
更新日期：2013-02-01 00:00:00
abstract：:The oral region comprises 1% of the total body area, yet it accounts for 5% of all bodily injuries. In preschool children, oral injuries make up as much as 17% of all bodily injuries. The incidence of traumatic dental injuries is 1%-3%, and the prevalence is steady at 20%-30%. The annual cost of treatment is US $2-$5 ...
journal_title：Journal of endodontics
pub_type： 杂志文章,评审
doi：10.1016/j.joen.2012.11.021
更新日期：2013-03-01 00:00:00
