Abstract：
:Nickel-titanium engine-driven rotary instruments are used increasingly in endodontic practice. One frequently mentioned problem is fracture of an instrument in the root canal. Very few studies have been conducted on torsional characteristics of these instruments, and none has been done under dynamic conditions. The purposes of this study were to measure the torque generated and the apical force applied during instrumentation with a commercial engine-driven nickel-titanium file system, and to relate torque generated during simulated clinical use to torsional failure of the instruments. Ten extracted human teeth (five with small-sized and five with medium-sized straight root canals) were instrumented with Quantec Series 2000 files, and the torque and apical force generated were measured. The applied apical force was generally low, not exceeding 150 g in either small or medium canals. The torque depended on the tip size and taper of each instrument, and on canal size. Instruments with 0.05 and 0.06 taper generated the highest torque, which was greater in small than in medium canals. The torque at failure was significantly (p < 0.001) higher than torque during instrumentation, but with considerable variation in the extent of the difference.
journal_name
J Endodjournal_title
Journal of endodonticsauthors
Sattapan B,Palamara JE,Messer HHdoi
10.1097/00004770-200003000-00007keywords:
subject
Has Abstractpub_date
2000-03-01 00:00:00pages
156-60issue
3eissn
0099-2399issn
1878-3554pii
S0099-2399(05)60946-6journal_volume
26pub_type
杂志文章abstract：:The aim of this study was to investigate fracture patterns occurring when a human upper central incisor is subjected to impact loadings at various angles. A two-dimensional finite element (FE) model of the maxillary incisor and surrounding tissues was established. The structural damping factor for the tooth was then c...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/01.don.0000157992.29221.41
更新日期：2005-10-01 00:00:00
abstract：:This study was carried out to investigate the effect of changes in tooth structure due to masticatory cycles on amalgam retrofillings performed to different cavity depths. Forty upper maxillary first molars were tested. In the obturated palatal root apical amalgam was inserted to different depths (1.5 and 3 mm). Eight...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(97)80169-0
更新日期：1997-10-01 00:00:00
abstract：:The purpose of this in vitro study was to evaluate the accuracy of Root ZX apex locator to determine the working length in teeth with simulated apical root resorption. Fifty extracted, single-rooted, human teeth with mature apices were used in this study. An irregular cavity defect was drilled at the apex of each toot...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200206000-00011
更新日期：2002-06-01 00:00:00
abstract：INTRODUCTION:Interferon regulatory factor 8 (IRF8) is a critical transcription factor in innate immune responses that regulates the development and function of myeloid cells. Human periapical lesions are caused by endodontic microbial infections. However, the presence of IRF8 in human periapical lesions remains elusive...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2018.04.015
更新日期：2018-08-01 00:00:00
abstract：:This study compared the microshear bond strength of three resin-based sealers to root dentin and assessed whether sealer cements behave differently in thin and thick films. Extracted maxillary premolars were sectioned buccolingually, and 45 root halves were randomly allocated for microshear bond testing with the three...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2008.10.009
更新日期：2009-01-01 00:00:00
abstract：:The aim of this study was to investigate the prevalence and configuration of the C-shaped canal using serial axial computed tomography images of the mandibular second molars that had not been restored severely or treated endodontically, and to compare the thickness of the remaining tooth structure from the center of t...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2005.10.007
更新日期：2006-01-01 00:00:00
abstract：INTRODUCTION:The aim of this study was to assess the root canal configurations in permanent mandibular lateral incisors (PMLIs) and the correlation between the root canal configurations of PMLIs with the appearance of a distolingual root (DLR) in permanent mandibular first molars (PMFMs) using cone-beam computed tomogr...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2017.08.027
更新日期：2018-01-01 00:00:00
abstract：:The purpose of this prospective, double-blind, randomized study was to evaluate pain reduction using an intraosseous injection of slow-releasing methylprednisolone in teeth with irreversible pulpitis. Forty subjects presenting for emergency treatment completed the study. Each subject had a tooth with a clinical diagno...
journal_title：Journal of endodontics
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1097/00004770-200011000-00001
更新日期：2000-11-01 00:00:00
abstract：INTRODUCTION:The direct effect of follicle-stimulating hormone (FSH) on bone resorption has been demonstrated recently. The aim of this study was to evaluate the effect of FSH inhibitor leuprorelin (LE) on alveolar bone loss resulting from experimental periapical lesions in ovariectomized (OVX) rats. METHODS:Twenty-se...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2010.01.011
更新日期：2010-04-01 00:00:00
abstract：INTRODUCTION:The retrieval of fractured instruments from root canals has been largely reported in the literature. However, a less complex retrieval method that causes minimum damage to the dental structures is needed. The aim of this article is to introduce a new concept of retrieval of fractured instruments from root ...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2009.11.024
更新日期：2010-04-01 00:00:00
abstract：:Fusion and gemination are developmental anomalies of the dental hard tissues that might require endodontic and surgical treatment for functional, orthodontic, or esthetic reasons. In this article, we report a rare case of successful endodontic management of unilateral fused mandibular second molar with a paramolar. Th...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2007.06.021
更新日期：2007-10-01 00:00:00
abstract：INTRODUCTION:The choice of single- versus multiple-visit root canal treatment for infected teeth is in dispute. The purpose of this systematic review was to compare the healing rate and post-obturation pain of single- versus multiple-visit root canal treatment for teeth with infected root canals. METHODS:An exhaustive...
journal_title：Journal of endodontics
pub_type： 杂志文章,评审
doi：10.1016/j.joen.2010.09.005
更新日期：2011-02-01 00:00:00
abstract：INTRODUCTION:Candida in endodontic infections has been investigated in a large number of studies, but its role as an endodontic pathogen is still debatable. The aim of this study was to systematically review the literature on the prevalence of Candida species in root canal infections. METHODS:Extensive literature rese...
journal_title：Journal of endodontics
pub_type： 杂志文章,meta分析
doi：10.1016/j.joen.2018.07.016
更新日期：2018-11-01 00:00:00
abstract：:The purpose of this in vitro study was to evaluate quantitatively the ability of four different filling materials to seal the orifices of root canals as a secondary seal after root canal therapy. Forty extracted human molar teeth were used. The top of pulp chambers and distal halves of the roots were removed using an ...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200108000-00006
更新日期：2001-08-01 00:00:00
abstract：INTRODUCTION:The aim of this study was to compare the efficacy of passive ultrasonic irrigation (PUI) and the EndoVac (EV) System (Discus Dental, Culver City, CA) in hard tissue debris removal and its influence on the quality of the root canal filling with the aid of micro-computed tomographic scanner. METHODS:Twenty-...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2015.05.001
更新日期：2015-10-01 00:00:00
abstract：INTRODUCTION:Irrigation dynamics and antibacterial activity determine the efficacy of root canal disinfection. Sonic or ultrasonic agitation of irrigants is expected to improve irrigation dynamics. This study examined the effects of microbubble emulsion (ME) combined with sonic or ultrasonic agitation on irrigation dyn...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2012.07.007
更新日期：2012-11-01 00:00:00
abstract：:Primary intraosseous salivary gland tumors are rare, with mucopidermoid carcinoma being the most frequent histotype. The authors present a case of adenoid cystic carcinoma, located in the mandibular incisor region, associated with pain. Endodontic treatment resulted in increased pain and progressive mandibular expansi...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200012000-00026
更新日期：2000-12-01 00:00:00
abstract：INTRODUCTION:The aim of this prospective, randomized, double-blind clinical trial was to evaluate the effect of a preoperative, single, oral dose of diclofenac potassium (DFK) on postoperative pain and rescue analgesic intake in patients with symptomatic irreversible pulpitis in mandibular molars treated in 1 visit. M...
journal_title：Journal of endodontics
pub_type： 杂志文章,随机对照试验
doi：10.1016/j.joen.2020.05.008
更新日期：2020-08-01 00:00:00
abstract：:EDTA-T and 10% citric acid used as root canal irrigants lead to more visible dentinal tubules than 5% sodium hypochlorite associated with 3% hydrogen peroxide. However, these cleansing agents must be compatible with apical periodontal tissue. We analyzed the cytotoxicity of 10% citric acid and EDTA-T in cultured fibro...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200112000-00007
更新日期：2001-12-01 00:00:00
abstract：INTRODUCTION:Previous studies in patients with irreversible pulpitis have reported increased success of the inferior alveolar nerve block (IANB) using premedication with ketorolac. Preemptive nitrous oxide administration has also shown an increase in the success of the IANB. Recently, ketorolac has been made available ...
journal_title：Journal of endodontics
pub_type： 杂志文章,随机对照试验
doi：10.1016/j.joen.2017.09.011
更新日期：2018-01-01 00:00:00
abstract：:Prostaglandins (PG) have been implicated in the genesis of periapical lesions. Periapical specimens from patients with clinical signs and symptoms of chronic and acute apical periodontitis were obtained and immediately frozen in liquid nitrogen. Periradicular tissues from unerupted third molars were frozen and used as...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(06)81737-1
更新日期：1991-03-01 00:00:00
abstract：:Whole genome DNA-DNA hybridization has been used to identify bacteria in periradicular lesions partly because there is no amplification of the bacteria, therefore, minor contaminants are not detected. There are, however, potential pitfalls with this technique, including inability to distinguish dead bacteria, cross-re...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200407000-00014
更新日期：2004-07-01 00:00:00
abstract：INTRODUCTION:The purpose of this study was to verify the expression of the calcium-sensing receptor (CaSR) and its role in mineral trioxide aggregate (MTA)-induced odontoblastic differentiation and mineralization in human dental pulp cells (hDPCs). METHODS:The expression of CaSR in human dental pulp tissue and hDPCs w...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2019.03.019
更新日期：2019-07-01 00:00:00
abstract：:Sixty-eight standardized human root specimens were infected with Enterococcus faecalis for 3 wk after removal of the smear layer. After 3 wk of infection, the smear layer was reformed and in half of the specimens, the smear layer was again removed. Aqueous Ca(OH)2 paste and silicone oil based Ca(OH)2 paste were used a...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/00004770-200105000-00004
更新日期：2001-05-01 00:00:00
abstract：INTRODUCTION:This study compared the accuracy of cone beam computed tomography (CBCT) scans made by five different systems in detecting vertical root fractures (VRFs). It also assessed the influence of the presence of root canal filling (RCF), CBCT slice orientation selection, and the type of tooth (premolar/molar) on ...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2009.09.013
更新日期：2010-01-01 00:00:00
abstract：INTRODUCTION:During apicoectomy and retrograde cavity preparation, a smear layer, which contains microorganisms and necrotic pulpal tissues, is formed on the dentinal surfaces cut by the instruments. Bacteria can survive and proliferate inside or below the smear layer. The purpose of this study was to evaluate in vitro...
journal_title：Journal of endodontics
pub_type： 杂志文章,随机对照试验
doi：10.1016/j.joen.2011.03.001
更新日期：2011-06-01 00:00:00
abstract：INTRODUCTION:The aim of this study was to compare the sensitivity and specificity of cone-beam computed tomography (CBCT) scans and digital periapical radiographs (PR) in detecting strip and root perforations after root canal treatment in mandibular molars. METHODS:Forty-five curved mesial roots were endodontically pr...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2010.12.003
更新日期：2011-04-01 00:00:00
abstract：INTRODUCTION:Concentrated growth factor (CGF) is considered to be a natural biomaterial that is better than platelet-rich fibrin (PRF) in bone regeneration, but there is little information acquired in regenerative endodontics. Therefore, the purpose of this study was to evaluate their effects on the proliferation, migr...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/j.joen.2018.03.006
更新日期：2018-06-01 00:00:00
abstract：:This study compared the quality of obturation of high- and low-temperature thermoplasticized injectable gutta-percha techniques and standard lateral condensation. A new model system was developed to more closely simulate the clinical environment. All obturations were performed in this same model which allowed direct c...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1016/S0099-2399(06)81863-7
更新日期：1991-06-01 00:00:00
abstract：:The purpose of this in vitro study was to investigate the canal configuration types, and the prevalence and location of anatomical variations in the mesiobuccal (MB) and mesial roots of permanent maxillary and mandibular first molars after instrumentation. The number and the type of canals were determined before instr...
journal_title：Journal of endodontics
pub_type： 杂志文章
doi：10.1097/01.don.0000145425.73364.91
更新日期：2005-05-01 00:00:00
