Comparison of Enamel Matrix Derivative Versus Formocresol as Pulpotomy Agents in the Primary Dentition
Jumana Sabbarini, BDS, MSc, Ahmed Mohamed, BDS, MSc, PhD, Nadia Wahba, BDS, MSc, PhD, Omar El-Meligy, BDS, MSc, PhD, Jeffrey Dean, DDS, MSD
The purpose of this study was to compare the clinical and radiographic success rates of two different pulpotomy agents: one novel agent, the biologically active odontogenic protein enamel matrix derivative (EMD) versus formocresol (FC). A randomized, single-blind, split-mouth study was used with a sample of 15 children aged 4 to 7 years (mean age, 5 ± 0.73 years). A total of 15 pairs of teeth, 1 pair per child, were selected for treatment. One tooth from each pair was randomly assigned to either the EMD pulpotomy group or the FC pulpotomy group. All teeth were followed up clinically and radiographically at 2, 4, and 6 months. After 6 months, the clinical success rates for the FC and EMD groups were 67% and 93%, respectively. Although most likely clinically relevant, the clinical success rate difference after 6 months was not statistically significant. After 6 months, the radiographic success rates for the FC and EMD groups were 13% and 60 %, respectively. There was a statistically significant difference at p ≤ 0.05. The clinical and radiographic assessment of EMD pulpotomized teeth in this study offers preliminary evidence that EMD is a promising material which may be as successful, or more so, than other pulpotomy agents.
Treatment Outcome in Endodontics: The Toronto Study—Phase 4: Initial Treatment
Cristian de Chevigny, DMD, MSc, Thuan T. Dao, DMD, MSc, PhD, Bettina R. Basrani, DDS, PhD, Vincent Marquis, DMD, MSc, Mahsa Farzaneh, DDS, MSc, Sarah Abitbol, DDS, MSc, Shimon Friedman, DMD
Outcome 4–6 years after initial treatment was assessed for Phase 4 (2000–2001) of the Toronto Study. Of 582 teeth treated, 430 were lost to follow-up (99 discontinuers, 331 dropouts), 15 were extracted, and 137 (32% recall minus 15 extracted teeth) were examined for outcome: healed (no apical periodontitis, signs, symptoms) or diseased. When pooled with Phases 1–3, 439 of 510 teeth (86%) were healed. Logistic regression identified 2 significant (P ≤ .05) preoperative outcome predictors: radiolucency (odds ratio [OR], 2.86; confidence interval [CI], 1.56–5.24; healed: absent, 93%; present, 82%) and number of roots (OR, 2.53; CI, 1.25–5.13; healed: single, 93%; multiple, 84%). In teeth with radiolucency, intraoperative complications (OR, 2.27; CI, 1.05–4.89; healed: absent, 84%; present, 69%) and root-filling technique (OR, 1.89; CI, 1.01–3.53; healed: lateral, 77%; vertical, 87%) were additional outcome predictors. A better outcome was suggested for teeth without radiolucency, with single roots, and without mid-treatment complications. The predictive value of root-filling technique in teeth with radiolucency requires validation from randomized controlled trials.
Comparative Study of Removal of Current Endodontic Fillings
Tamer Taşdemir, DDS, PhD, Tahsin Yildirim, DDS, PhD, Davut Çelik, DDS
The aim of the present study was to assess the removability of canal fillings performed by using current methods during re-treatment with rotary instruments. Seventy-two freshly extracted human anterior teeth with single straight root canals were instrumented with Mtwo rotary files. The teeth were randomly divided into 4 obturation groups of 18 specimens each as follows: group 1, Resilon and Epiphany; group 2, GuttaFlow obturation system; group 3, EndoTwinn obturation system; group 4, gutta-percha with AH Plus sealer. The filled canals were re-treated by using Mtwo-Retreatment instruments and Mtwo instruments. The time required to remove the obturation material was recorded. After splitting the roots, the amount of residual filling material on the canal walls was imaged and measured with image analyzer software. Statistical analysis was accomplished by Kruskal-Wallis and Mann Whitney U tests for the analysis of root canal cleanliness. There was no statistically significant difference among the 4 filling techniques regarding the amount of residual material in the apical, middle, and coronal thirds and inside the whole canal area (P > .05). Regarding the mean time of re-treatment, the fillings performed by using GuttaFlow and EndoTwinn methods were removed much more quickly compared with the other 2 methods (P < .001). It was observed that the fillings performed with the above canal filling methods were removed in a similar fashion with rotary instruments during re-treatment.
The Resolution of a Periradicular Lesion Involving an Implant
David R. Steiner, DDS, MSD
Published reports claim that implants can fail from endodontic pathosis involving teeth adjacent to an implant, from preexisting bacteria in an extraction site that had a history of a tooth having a periradicular lesion, and even from an asymptomatic endodontically treated tooth with no clinical or radiographic evidence of pathosis. This report considers the support offered for an endodontic connection to implant failure, and it presents a case that conflicts with the premise that endodontic involvement causes implant failure. The diagnosis and treatment of a radiolucent lesion associated with an implant is described. Although initially interpreted as indicating a failing implant, the etiology of the radiolucency was a necrotic pulp in a maxillary lateral incisor with resorption. Nonsurgical endodontic treatment that combined Ca(OH)2 for interim treatment and mineral trioxide aggregate for final obturation completely resolved the periradicular lesion abutting the implant and successfully retained both the implant and the resorbed lateral incisor.
Light Transmission through a Translucent Fiber Post
Luís Fernando dos Santos Alves Morgan, DDS, Rogéli Tiburcio Ribeiro da Cunha Peixoto, DDS, MSc, Rodrigo de Castro Albuquerque, DDS, MSc, PhD, Maurício Ferrari Santos Corrêa, DScEng, Luiz Thadeu de Abreu Poletto, DDS, MSc, PhD, Marcos Barbosa Pinotti, DDS, MSc, PhD
This study is a quantitative assessment of the luminous energy transmitted through different translucent fiber posts. After embedding the posts in black resin, the blocks were submitted to sequential cuts in a precision machine, and depths of 16 mm, 12 mm, 8 mm, and 4 mm were assessed for light transmission with a digital photometer. The quantitative analysis showed significant differences between different posts and depths. Furthermore, the values obtained revealed that the quantity of luminous energy transmitted depends on the type of post and that for all of them there was a significant reduction of the quantity of light transmitted as the depth increased. Even without the post, the luminous intensity inside the canal seems to decrease to levels that are insufficient for polymerization, especially in the apical third.
Up-regulation of Gelatinases and Tissue Type Plasminogen Activator by Root Canal Sealers in Human Osteoblastic Cells
Fu-Mei Huang, DDS, MS, PhD, Shun-Fa Yang, PhD, Yu-Chao Chang, DDS, MS, PhD
Histologic investigations have demonstrated that root canal sealers can induce mild to severe inflammatory alternations. However, there is little information on the precise mechanisms about root canal sealer–induced inflammatory reaction. The proteolysis of extracellular matrix by matrix metalloproteinases (MMPs) and plasminogen activators (PAs) seems to be a key initiating event for the progression of the inflammatory process. The aim of this study was to investigate the effects of epoxy resin–based root canal sealer AH26 and zinc oxide–eugenol–based root canal sealer Canals and one paste sealer N2 on the expression of MMPs and PAs in human osteoblastic cell line U2OS cells. The levels of gelatinolytic and caseinolytic activities were measured by gelatin and casein zymography. The results showed that AH26, Canals, and N2 were cytotoxic to U2OS cells in a concentration-dependent manner (P < .05). The gelatin zymograms revealed that MMP-2 (72 kd) and MMP-9 (92 kd) were secreted by U2OS cells. The exposure of U2OS cells to root canal sealers resulted in the up-regulation of MMP-2 and MMP-9 expression (P < .05). Casein zymography exhibited a caseinolytic band with a molecular weight of 70 kd, indicative of the presence of tissue type plasminogen activators (t-PA). t-PA was also found to be up-regulated by root canal sealers (P < .05). Taken together, the activation of gelatinases and t-PA might play an important role in the pathogenesis of root canal sealer–induced periapical inflammation.
A Novel Polyurethane-based Root Canal–obturation Material and Urethane Acrylate–based Root Canal Sealer—Part I: Synthesis and Evaluation of Mechanical and Thermal Properties
Kuo-Huang Hsieh, BS, MS, PhD, Ken-Hsuan Liao, BS, MS, Eddie Hsiang-Hua Lai, Bor-Shiunn Lee, DDS, MS, PhD, Chung-Yi Lee, DDS, MS, Chun-Pin Lin, DDS, MS, PhD
Resilon (RealSeal; SybronEndo, Orange, CA) has been developed as an alternative to gutta percha, but its advantages over gutta percha remain controversial. In this study, we developed a novel zinc oxide/thermoplastic polyurethane (ZnO/TPU) composite root canal–filling material and a visible-light curable urethane-acrylate/tripropylene glycol diacrylate (UA/TPGDA) root canal sealer. The mechanical and thermal properties of the ZnO/TPU composite were compared with those of gutta percha and Resilon. Results showed that the tensile strength and elastic modulus of the ZnO/TPU composite were markedly higher than those of gutta percha and Resilon. The melting points of all three materials were similar; however, the enthalpy change and specific heat of ZnO/TPU (9.4 J/g, 0.7 J/g°C) were close to those of gutta percha (10.9 J/g, 0.7 J/g°C) but lower than those of Resilon (28.9 J/g, 1.3 J/g°C). The results indicate that ZnO/TPU composite exhibits better mechanical strength than Resilon, and its combination with UA/TPGDA sealer has excellent potential to be used as a root canal–filling material.
Accuracy of Cone Beam Computed Tomography and Panoramic and Periapical Radiography for Detection of Apical Periodontitis
Carlos Estrela, DDS, MSc, PhD, Mike Reis Bueno, DDS, MSc, Cláudio Rodrigues Leles, DDS, MSc, PhD, Bruno Azevedo, DDS, MSc, José Ribamar Azevedo, DDS
The aim of this study was to evaluate the accuracy of imaging methods for detection of apical periodontitis (AP). Imaging records from a consecutive sample of 888 imaging exams of patients with endodontic infection (1508 teeth), including cone beam computed tomography (CBCT) and panoramic and periapical radiographs, were selected. Sensitivity, specificity, predictive values, and accuracy of periapical and panoramic radiographs were calculated. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic accuracy of the panoramic and periapical images. Prevalence of AP was significantly higher with CBCT. Overall sensitivity was 0.55 and 0.28 for periapical and panoramic radiographs, respectively. ROC curves and area under curve (AUC) with periapical radiography showed a high accuracy for the cutoff value of 5 for both periapical (AUC, 0.90) and panoramic (AUC, 0.84) radiographs. AP was correctly identified with conventional methods when showed advanced status. CBCT was proved to be accurate to identify AP.
Evaluation of Root Canal Dentin after Nd:YAG Laser Irradiation and Treatment with Five Different Irrigation Solutions: A Preliminary Study
Taskin Gurbuz, DDS, PhD, Yuksel Ozdemir, DDS, PhD, Nihal Kara, DDS, Cigdem Zehir, DDS, Murat Kurudirek, DDS
This study evaluated in vitro any changes in the morphology and mineral content of root canal dentin after treatments with Nd:YAG laser irradiation and 5 different irrigation solutions. The groups of extracted single-rooted human teeth were exposed to sterile saline solution, 5.25% NaOCl, 3% H2O2, 15% ethylenediaminetetraacetic acid, 2% chlorhexidine gluconate, and Nd:YAG laser irradiation. All prepared teeth were bisected longitudinally; half of each tooth was used for wavelength dispersive x-ray fluorescence spectrometry analysis to assess the mineral content. The other half was studied by using scanning electron microscopy to analyze the surface of the dentin. The results showed that the calcium level and calcium/phosphorus ratio decreased significantly with the NaOCl irrigation solutions (p < .05), suggesting the presence of changes at molecular level. Significant differences among the test groups were also observed in the scanning electron microscopy evaluation (p < .05). The lowest scores for root cleaning were obtained by using ethylenediaminetetraacetic acid followed by Nd:YAG laser treatment.
The Substitution of Chlorhexidine for Doxycycline in MTAD: The Antibacterial Efficacy Against a Strain of Enterococcus faecalis
Shahrokh Shabahang, DDS, MS, PhD, Joseph Aslanyan, DDS, Mahmoud Torabinejad, DMD, MSD, PhD
The antimicrobial effect of MTAD has been largely attributed to the presence of doxycycline. In the present study, chlorhexidine was added to or substituted for doxycycline to compare these three formulations in their ability to disinfect extracted human teeth infected with Enterococcus faecalis. Ten teeth were used in each group along with positive and negative controls. The teeth were treated according to previously published protocols. None of the samples treated with MTAD or MTAD + chlorhexidine showed the presence of residual bacteria. In contrast, 7 of 10 samples treated with MCAD (chlorhexidine substituted for doxycycline) showed positive cultures of E. faecalis. The results clearly showed that although the addition of chlorhexidine did not negatively impact the efficacy of MTAD, the substitution of this antimicrobial agent for doxycycline significantly reduces the efficacy of the solution.
Outcome of One-visit and Two-visit Endodontic Treatment of Necrotic Teeth with Apical Periodontitis: A Randomized Controlled Trial with One-year Evaluation
Vince A. Penesis, DDS, Patrick I. Fitzgerald, DDS, Mohamed I. Fayad, DDS, MS, PhD, Christopher S. Wenckus, DDS, FICD, Ellen A. BeGole, PhD, Bradford R. Johnson, DDS, MHPE
The choice of one-visit versus two-visit root canal therapy for necrotic teeth with apical periodontitis is a source of current debate. The primary objective of this randomized controlled clinical trial was to compare radiographic evidence of periapical healing after root canal therapy completed in one visit or two visits with an interim calcium hydroxide/chlorhexidine paste dressing. Ninety-seven patients met the inclusion criteria and consented to participate in this study. Patients were randomly assigned to either the one-visit or two-visit group, and root canal therapy was performed with a standardized protocol. Patients in the two-visit group received an intracanal dressing of calcium hydroxide/chlorhexidine paste. Sixty-three patients, 33 in the one-visit group and 30 in the two-visit group, were evaluated at 12 months. The primary outcome measure was change in apical bone density by using the periapical index (PAI). Secondary outcome measures were proportion of teeth healed or improved in each group. Both groups exhibited equally favorable periapical healing at 12 months, with no statistically significant differences between groups.
Bond Strength of Fiber Posts after the Application of Erbium:Yttrium-Aluminum-Garnet Laser Treatment and Gaseous Ozone to the Root Canal
Kerstin Bitter, DDS, Jörn Noetzel, DDS, Claudia Volk, DDS, Konrad Neumann, Andrej Michael Kielbassa, DDS, PhD
The aim of the present study was to investigate the effects of antibacterial agents (erbium:yttrium-aluminum-garnet [Er:YAG] laser or gaseous ozone) intended to disinfect root canals on bond strengths of fiber posts compared with canals that were finally irrigated using chlorhexidine (CHX). One hundred forty-four human anterior teeth were divided into three groups (n = 48); root canal instrumentation was performed, and antimicrobial pretreatment was conducted as follows: control group: CHX, group 2: Er:YAG laser, and group 3: gaseous ozone. In all groups, fiber posts were inserted using Panavia F 2.0 (Kuraray, Osaka, Japan), Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein), RelyX Unicem (3M Espe; Seefeld, Germany), or Ketac Cem (3M Espe) (n = 12 each). Push-out bond strengths to root canal dentin were affected by the type of luting agent but not by the antimicrobial pretreatment regimen. However, significant interactions between the luting agent and pretreatment could be observed, and adhesion of the self-adhesive resin cement RelyX Unicem was significantly reduced after using gaseous ozone.
Management of a Multiple Dentoalveolar Trauma in Permanent Dentition with Avulsion of a Canine: A 4-Year Follow-up
Andrea Melo Senes, DDS, MSc, Vivien T. Sakai, DDS, MSc, Thais Marchini Oliveira, DDS, PhD, Maria Aparecida A.M. Machado, DDS, PhD, Carlos F. Santos, DDS, PhD, Clóvis Marzola, DDS, PhD
Traumatic dental injuries are relatively frequent accidents that typically involve teeth in the maxillary anterior segment. The emergency treatment and the clinical decisions must be efficiently made at the time of injury, and there is a need for long-term follow-up because of the high incidence of complications. The aim of this article was to present the emergency and rehabilitation treatments of a multiple dentoalveolar trauma in the permanent dentition involving different extensions of enamel-dentin crown fracture, pulp exposure, and the avulsion of a canine. The treatment outcomes are reported up to the 4-year follow-up, and the clinical approaches and their rationale are discussed.
Vital Signs of the Emergency Patient with Pulpal Necrosis and Localized Acute Apical Abscess
Chad A. Campanelli, DDS, Richard E. Walton, DMD, MS, Anne E. Williamson, DDS, MS, David R. Drake, MS, PhD, Fang Qian, PhD
Vital signs aid in assessing patient health and the disease severity. The objectives of this study were to determine changes in vital signs of patients with pulpal necrosis (PN) and acute apical abscess (AAA). The vital signs measured at the emergency visit were blood pressure, heart rate, temperature, and lymphadenopathy. Visual analogue scales (VASs) were used to assess (1) pain and (2) malaise. Emergency treatment was rendered. At a subsequent (baseline) visit and with clinical symptoms resolved, systemic vital sign measurements and VASs were repeated. The presence or absence of swelling with vital signs and VASs of pain and swelling were compared. Compared with baseline, data showed no marked elevation in temperature, blood pressure, or lymphadenopathy, regardless of presence or absence of swelling. VAS measurements of pain and malaise did show statistically significant higher numbers at the emergency appointment, indicating a difference from baseline. Swelling versus no swelling did not differ. Vital signs were not impacted by localized AAA, although pain and malaise were greater. Vital signs might not be useful determinants of treatment or pharmacotherapeutic measures with localized AAA.
Reduced Long-term Sealing Ability of Adhesive Root Fillings after Water-storage Stress
Gustavo De-Deus, DDS, MS, Fátima Namen, DDS, MS, PhD, João Galan Jr, DDS, MS, PhD
This study was designed to compare in vitro the short-term and long-term ability to prevent through-and-through fluid movement along Resilon/Epiphany root fillings. A sample of 40 human upper incisors were prepared and assigned to experimental groups of 20 teeth each, designated as G1, Resilon/Epiphany, and G2, gutta-percha/AH Plus. Additional 10 teeth were used as controls. Each tooth was assembled in a hermetic cell to allow the evaluation of fluid filtration. After the root filling procedures, the filled roots were stored at 37°C and 100% humidity for 7 days to allow setting of the sealer. Forthwith, the teeth were submitted to the first fluid flow measurement. Leakage was measured by the movement of an air bubble traveling within a pipette connected to the teeth. Shortly after the measurements, the teeth were detached from the hermetic cell and then stored in water for 14 months at 37°C. At this moment, fluid filtration was re-measured. Both Kruskal-Wallis and Wilcoxon signed rank tests were applied to detect differences between the experimental groups. No differences were found between the experimental groups during the immediate measure (P > .05), whereas Resilon/Epiphany group displayed significantly more fluid movement than the gutta-percha/AH Plus group after 14 months of water storage (P < .05). The water-storage stress had no significant effect on the sealing ability of the gutta-percha/AH Plus root fillings (P > .05). The main point of our study is the fact that long-term sealing was compromised in the Resilon/Epiphany samples, when exposed to long-term water storage.
Accuracy of Two Apex-locating Handpieces in Detecting Simulated Vertical and Horizontal Root Fractures
Özgür Topuz, DDS, PhD, Özgür Uzun, DDS, PhD, A. Cemal Tinaz, DDS, PhD, Emre Bodrumlu, DDS, PhD†, Güliz Görgül
The aim of this study was to evaluate in vitro the effectiveness of TCM Endo V and Tri Auto ZX handpieces in detecting simulated horizontal and vertical root fractures. Forty extracted maxillary incisor teeth were randomly divided into 2 groups as simulated incomplete horizontal and vertical root fractures. Auto reverse and electronic apex locator functions of the 2 handpieces were used in both groups. Repeated measures of analysis test and pairwise comparisons were used for statistical analyses. Both handpieces detected the root fractures in an acceptable range. Furthermore, electronic apex locator function of both devices was more efficient in the process than auto reverse function.
The Efficacy of IntraFlow Intraosseous Injection as a Primary Anesthesia Technique
Todd Remmers, DMD, Gerald Glickman, DDS, MS, Robert Spears, PhD, Jianing He, DMD, PhD
The purpose of this study was to compare the efficacy of intraosseous injection and inferior alveolar (IA) nerve block in anesthetizing mandibular posterior teeth with irreversible pulpitis. Thirty human subjects were randomly assigned to receive either intraosseous injection using the IntraFlow system (Pro-Dex Inc, Santa Ana, CA) or IA block as the primary anesthesia method. Pulpal anesthesia was evaluated via electric pulp testing at 4-minute intervals for 20 minutes. Two consecutive 80/80 readings were considered successful pulpal anesthesia. Anesthesia success or failure was recorded and groups compared. Intraosseous injection provided successful anesthesia in 13 of 15 subjects (87%). The IA block provided successful anesthesia in 9 of 15 subjects (60%). Although this difference was not statistically significant (p = 0.2148), the results of this preliminary study indicate that the IntraFlow system can be used as the primary anesthesia method in teeth with irreversible pulpitis to achieve predictable pulpal anesthesia.
Quantification of Endotoxins and Cultivable Bacteria in Root Canal Infection before and after Chemomechanical Preparation with 2.5% Sodium Hypochlorite
Frederico C. Martinho, MSc, Brenda P.F.A. Gomes, PhD
This clinical study was conducted to quantify endotoxins and cultivable bacteria in teeth with pulp necrosis and apical periodontitis before and after chemomechanical preparation with 2.5% sodium hypochlorite (NaOCl) and to investigate the possible correlation of endotoxin and cultivable bacteria with the presence of clinical symptomatology. Twenty-four root canals were selected. Samples were collected before (s1) and after chemomechanical preparation (s2). Culture techniques were used to determine the colony-forming unit. A limulus amebocyte lysate (LAL) assay was used to quantify endotoxins (lipopolysaccharide, LPS). LPS and bacteria were detected in 100% of the initial samples (s1), with a median concentration of 139 endotoxin units/mL and 2.64 × 105 colony-forming units/mL, respectively. Higher levels of LPS were found in teeth with clinical symptomatology (p < .05). At s2, mean endotoxin reduction of 59.99% and mean bacterial load reduction of 99.78% were found. Our findings indicated that chemomechanical preparation with 2.5% NaOCl was moderately effective against bacteria but less effective against endotoxins in root canal infection. Furthermore, a statistically significant association was found between higher levels and clinical symptomatology.
An Evaluation of GuttaFlow and Gutta-Percha in the Filling of Lateral Grooves and Depressions
Tracie M. Zielinski, DDS, J. Craig Baumgartner, DDS, PhD, J. Gordon Marshall, DMD
The purpose of this study was to compare the flow of GuttaFlow (Coltène/Whaledent Inc, Cuyahoga Falls, OH) and gutta-percha into lateral grooves and depressions in the apical 7 mm of the root canal system. A maxillary canine was used to fabricate a split-tooth model with depressions and lateral grooves placed in the canal walls at 1 mm, 3 mm, 5 mm, and 7 mm from the working length. The model was obturated with GuttaFlow or gutta-percha and Roth’s 801 sealer (Roth International, Chicago, IL). Obturations with gutta-percha were performed by using warm vertical compaction with the System B plugger (Analytic Endodontics, Orange, CA) advanced to 5 mm, 4 mm, or 3 mm from the working length. All obturations with GuttaFlow showed extrusion of material beyond the apex. GuttaFlow completely obturated the grooves and depressions at all levels from the working length, and, at the 1-mm level, GuttaFlow flowed significantly better into grooves. GuttaFlow flowed better than gutta-percha into depressions at the 1-mm level when the System B plugger was inserted to 5 mm and 4 mm from the working length, but no significant differences were seen when the System B plugger was inserted to 3 mm from the working length. Gutta-percha flowed significantly better into grooves and depressions at the 1-mm level when the System B plugger was inserted 3 mm from the working length compared with 5 mm and 4 mm from working length.
Hand-operated and Rotary ProTaper Instruments: A Comparison of Working Time and Number of Rotations in Simulated Root Canals
Damiano Pasqualini, DDS, Nicola Scotti, DDS, Lorenzo Tamagnone, DDS, Federica Ellena, DDS, Elio Berutti, MD, DDS
The aim of this study was to compare the effective shaping time and number of rotations required by an endodontist working with hand and rotary ProTaper instruments to completely shape simulated root canals. Eighty Endo Training Blocks (curved canal shape) were used. Manual preflaring was performed with K-Flexofiles #08-10-12-15-17 and #20 Nitiflex at a working length of 18 mm. Specimens were then randomly assigned to 2 different groups (n = 40); group 1 was shaped by using hand ProTaper and group 2 with ProTaper rotary. The number of rotations made in the canal and the effective time required to achieve complete canal shaping were recorded for each instrument. Differences between groups were analyzed with the nonparametric Mann-Whitney U test (P < .05). Hand ProTaper required significantly fewer rotations (P < .001) than rotary ProTaper, whereas the effective working time to fully shape the simulated canal was significantly higher (P < .001) with hand ProTaper.