Journal of Endodontics

Response of Human Dental Pulp Capped with Biodentine and Mineral Trioxide Aggregate

2013-04-15

Abstract: Introduction: Biodentine is a new bioactive cement that is similar to the widely used mineral trioxide aggregate (MTA). It has dentin-like mechanical properties, which may be considered a suitable material for clinical indications of dentin-pulp complex regeneration such as direct pulp capping. The purpose of the present study was to compare the response of the pulp-dentin complex in human teeth after direct capping with this new tricalcium silicate–based cement with that of MTA.Methods: Pulps in 28 caries-free maxillary and mandibular permanent intact human molars scheduled for extraction for orthodontic reasons were mechanically exposed and assigned to 1 of 2 experimental groups, Biodentine or MTA, and 1 control group. Assay of periapical response and clinical examination were performed. After 6 weeks, the teeth were extracted, stained with hematoxylin-eosin, and categorized by using a histologic scoring system.Results: The majority of specimens showed complete dentinal bridge formation and an absence of inflammatory pulp response. Layers of well-arranged odontoblast and odontoblast-like cells were found to form tubular dentin under the osteodentin. Statistical analysis showed no significant differences between the Biodentine and MTA experimental groups during the observation period.Conclusions: Within the limitations of this study, Biodentine had a similar efficacy in the clinical setting and may be considered an interesting alternative to MTA in pulp-capping treatment during vital pulp therapy.

Maxillary Sinus and Posterior Teeth: Accessing Close Relationship by Cone-beam Computed Tomographic Scanning in a Brazilian Population

2013-03-25

Abstract: Introduction: This study aimed to evaluate the close proximity established between the maxillary sinus floor and posterior teeth roots apices by using cone-beam computed tomographic scanning.Methods: The relationship of maxillary sinuses and posterior teeth roots, which were divided into 2 groups, was analyzed using i-CAT Vision software (Imaging Sciences, Hatfield, PA). Group 1 included all root apices found in close contact with the maxillary sinus floor without sinus floor elevation, whereas group 2 included all root apices that were protruded within the sinus producing an elevation of the bony cortical.Results: A total of 100 maxillary sinuses and 601 roots apices were evaluated. Group 1 presented 130 of 601 (21.6%) roots and group 2 presented 86 of 601 (14.3%) roots.Conclusions: The second molar mesiobuccal root apex is frequently found in close proximity with the sinus floor, and the relation between these anatomic structures should be considered in order to prevent an iatrogenic procedure and minimize the risks from an infectious disease within the sinus.

Altered Coronal Tissue of the Human Dental Pulp in Chronic Hepatitis C Virus Infected Patients

2013-01-21

Abstract: Introduction: Hepatitis C virus (HCV) infection is characterized by a high rate of chronicity and concerns 170 million individuals worldwide. Extrahepatic manifestations are frequently observed in patients with chronic viral hepatitis. Although extrahepatic manifestations do exist with all hepatitis viruses, they are more commonly associated with chronic HCV infection. This study aimed to evaluate qualitatively and quantitatively the effect of chronic HCV infection on the coronal tissue of the human dental pulp.Methods: Thirty sound impacted teeth were obtained from healthy individuals as healthy controls. The patient group included another 30 sound impacted teeth obtained from chronic HCV–infected patients. The coronal pulp tissues were carefully removed, fixed, and processed to be stained with hematoxylin-eosin, alcian blue (2.5)/periodic acid–Schiff, van Gieson, and fibronectin.Results: The tissue sections of chronic HCV patients revealed disorganized pulp tissue, chronic inflammatory cell infiltrate, thickening, stenosis and occlusion of large-sized blood vessel arteriole, and collapsed venule and lymphatic system. The acidic, neutral, and mixed mucins were increased, whereas the amount of collagen was decreased, accompanied with marked decrease in the distribution and quantity of fibronectin glycoprotein. Application of Kruskal-Wallis test showed that there were statistically significant changes between the 2 groups (P ≤ .05).Conclusions: The coronal tissue of the dental pulp, like any other body tissues, is affected by chronic HCV infection, with an inappropriate cellularity, vasculature, and extracellular matrix proteins. The clinician should be alerted to these histologic changes and their subsequent implications.

The Critical Apical Diameter to Obtain Regeneration of the Pulp Tissue after Tooth Transplantation, Replantation, or Regenerative Endodontic Treatment

Wim G.M. Laureys, Claude A. Cuvelier, Luc R. Dermaut, Guy A.M. De Pauw — 2013-04-01

Abstract: Introduction: Regeneration of pulp-like tissue in the pulp chamber after tooth transplantation, replantation, or in regenerative endodontic treatment is only possible if the apical foramen is open. According to the literature, the success of regeneration decreases considerably if the foramen is smaller than 1 mm when measured on radiographs. The aim of this study was to study histologically the relation between the width of the apical foramen and regeneration of tissue in the pulp chamber after autotransplantation.Methods: Fifteen single-rooted mature teeth of 3 adult beagle dogs were used. All experimental teeth were extracted and underwent apicoectomy. The teeth were photographed from the apical side, and the width of the foramen was calculated. The foramen width ranged from 0.24–1.09 mm. All teeth were replanted in infraocclusion. The observation period was 90 days after transplantation.Results: The 10 teeth with the smallest apical diameter, ranging between 0.24 and 0.53 mm, showed vital tissue in at least one third of the pulp chamber. The 6 most successful teeth showing vital tissue in the entire pulp chamber had an apical diameter between 0.32 and 0.65 mm, and 80% of the experimental teeth with a diameter varying between 1.09 and 0.31 mm showed vital tissue in at least one third of the pulp chamber 90 days after transplantation.Conclusions: The size of the apical foramen seems not to be the all decisive factor for successful revascularization and ingrowth of new tissue after transplantation. The minimum width of the apical foramen has not been determined, but a size smaller than 1 mm does not prevent revascularization and ingrowth of vital tissue. In this animal study an apical foramen of 0.32 mm did not prevent ingrowth of new tissue in two-thirds of the pulp chamber 90 days after transplantation.

Ketoprofen Inhibits Expression of Inflammatory Mediators in Human Dental Pulp Cells

2013-04-01

Abstract: Introduction: Conventional root canal treatment is the treatment of choice for the irreversible pulpitis caused by bacterial infection. More recently, vital pulp therapy has been proposed as an alternative for management of inflamed dental pulp. Ketoprofen is an anti-inflammatory agent commonly used as a component of mouth rinse for oral lesions. Here, we examined the effect and mechanisms of action of ketoprofen on the expression of inflammatory mediators induced by the lipopolysaccharide (LPS) in dental pulp cells.Methods: Human dental pulp cells were exposed to LPS or LPS + ketoprofen, and reverse-transcription polymerase chain reaction was used to detect interleukin-1β and tumor necrosis factor α. The effect of these treatments on mitogen-activated protein kinase pathways was assessed by Western blots for extracellular signal–regulated kinase and c-Jun N-terminal kinase.Results: LPS induced interleukin-1β and tumor necrosis factor α in dental pulp cells. Ketoprofen effectively inhibited interleukin-1β and tumor necrosis factor α production in LPS-stimulated dental pulp cells. Notably, ketoprofen inhibited phosphorylation of extracellular signal–regulated kinase and c-Jun N-terminal kinase.Conclusions: Ketoprofen inhibited expression inflammatory mediators in dental pulp cells stimulated with LPS. The inhibitory effect of ketoprofen on inflammatory cytokines is associated with inhibition of the mitogen-activated protein kinase pathway.

Adenosine Monophosphate–activated Protein Kinase/Mammalian Target of Rapamycin–dependent Autophagy Protects Human Dental Pulp Cells against Hypoxia

2013-03-18

Abstract: Introduction: Human dental pulp cells (HDPCs) are recalcitrant to hypoxic stress. We investigated whether hypoxia-induced autophagy of HDPCs offered these cells a survival advantage and the underlying mechanism of this resistance.Methods: The viability and apoptosis of HDPCs were examined after exposure to hypoxia by Vi-CELL cell viability analyzer and flow cytometry. Autophagy was assessed by using immunofluorescence, acridine orange staining, real-time polymerase chain reaction, and Western blotting. Either 3-methyladenine or expression vectors encoding dominant negative ATG5 were used to inhibit autophagy. Rapamycin was used as an autophagic inducer. To explore the mechanisms of autophagy, adenosine monophosphate–activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway and hypoxia-inducible transcription factor-1 were suppressed by chemical inhibitors Compound C and YC-1, respectively.Results: The exposure of HDPCs to hypoxia had no effect on viability and resulted in increasing acidic vesicular organelle-positive cells, autophagosome formation, and up-regulation of autophagy genes. Inhibition of autophagy with 3- methyladenine or expression vectors encoding dominant negative ATG5 abrogated the protective effects of HDPCs. The phosphorylation of AMPK was up-regulated, whereas the phosphorylation of mTOR was down-regulated in hypoxia-treated HDPCs, which were both attenuated by Compound C. Furthermore, treatment with Compound C rather than YC-1 reduced the autophagy.Conclusions: Our results suggested that autophagy of HDPCs might be cytoprotective against hypoxic stress via the AMPK/mTOR signaling pathway.

Bioactivity of Calcium Aluminate Endodontic Cement

2013-03-25

Abstract: Introduction: Calcium aluminate endodontic cement (CAEC) developed for use in root canal therapy has been produced with additives that improve handling properties and provide higher mechanical strength than mineral trioxide aggregate (MTA) according to prior studies. The aim of this study was to evaluate the bioactivity of CAEC containing accelerating additives (A-CAEC) in comparison with MTA, both in contact with simulated body fluid (SBF) solutions.Methods: pH measurements were taken for set cement samples immersed in water or SBF solutions prepared according to the Kokubo and Rigo techniques. The surface of these materials kept in contact with SBF solutions were also evaluated by means of scanning electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction.Results: Because of the calcium hydroxide dissociation, MTA cement is able to release more Ca2+ ions and results in a higher pH increase compared with A-CAEC. This behavior enhances the supersaturation of Kokubo solution, resulting in the precipitation of calcium phosphate phases on the MTA surface. On the other hand, for MTA in Rigo SBF solution, the pH value attained was higher than for the Kokubo SBF solution as a result of the Mg2+ ion precipitation, which inhibited the calcium phosphate phase formation. For A-CAEC, the optimal precipitation conditions of calcium phosphate phases are achieved in Rigo SBF solution.Conclusions: MTA and A-CAEC present bioactivity in contact with SBF solution although the composition of this solution defines the type of phase precipitated.

Hypotonic-induced Stretching of Plasma Membrane Activates Transient Receptor Potential Vanilloid Channels and Sodium–Calcium Exchangers in Mouse Odontoblasts

2013-03-18

Abstract: Introduction: A number of transient receptor potential (TRP) channels have been identified as membrane-bound sensory proteins in odontoblasts. However, the activation properties of these channels remain to be clarified. The purpose of this study was to investigate hypotonic stimulation–induced Ca2+ entry via TRP vanilloid subfamily member (TRPV) 1, TRPV2, and TRPV4 channels, which are sensitive to osmotic and mechanical stimuli, and their functional coupling with Na+-Ca2+ exchangers (NCXs) in mouse odontoblast lineage cells.Methods: We examined TRP channel activity by measuring intracellular-free Ca2+ concentration by using fura-2 fluorescence and ionic current recordings with whole-cell patch-clamp methods. Protein localization and messenger RNA expression were characterized using immunofluorescence and reverse-transcription polymerase chain reaction analyses.Results: Extracellular hypotonic solution–induced stretching of plasma membrane resulted in the activation of Ca2+ influx and inward currents. TRPV1, TRPV2, and TRPV4 channel antagonists inhibited the hypotonic stimulation–induced Ca2+ entry and currents. Their respective agonists activated Ca2+ entry. Although the increase in the intracellular free Ca2+ concentration decayed rapidly after the applications of these TRPV channel agonists, NCX inhibitors significantly prolonged the decay time constant. The messenger RNA expression of TRPV1, TRPV2, and TRPV4 channels; NCX isoforms 2 and 3; and dentin sialophosphoprotein were up-regulated after 24 hours of exposure to the hypotonic culture medium.Conclusions: These results indicate that stretching of the odontoblast membrane activates TRPV1-, TRPV2-, and TRPV4-mediated Ca2+ entry, and increased intracellular-free Ca2+ concentration is extruded via NCXs. These results suggest that odontoblasts can act as sensors that detect stimuli applied to exposed dentin and drive a number of cellular functions including dentinogenesis and/or sensory transduction.

Local Injection of Pulp Cells Enhances Wound Healing during the Initial Proliferative Phase through the Stimulation of Host Angiogenesis

2013-03-25

Abstract: Introduction: The aim of this study was to examine the effect of pulp cell injection on host angiogenesis during wound healing.Methods: Pulp cells were isolated from extracted premolars by the outgrowth method. Fluorescently labeled pulp cells or phosphate-buffered saline were locally injected into a mouse wound healing model. Wound healing was evaluated using photographs, histology, and real-time reverse-transcription polymerase chain reaction. Injected cells were traced. Angiogenesis was measured by performing immunohistochemical staining of CD31, a marker of vascular endothelial cells. The level of secreted vascular endothelial growth factor in the pulp cell conditioned medium (CM) was compared with the CM of fibroblasts and keratinocytes. The paracrine effect of pulp CM on angiogenesis was evaluated by tubular network formation using endothelial cells.Results: The local injection of pulp cells enhanced wound closure during the initial stage when compared to the injection of phosphate-buffered saline. The amount of extracellular matrix production and the expression of CD31+ cells were also increased in response to pulp cell injection when compared with the injection of phosphate-buffered saline. The fluorescently labeled pulp cells were engrafted into the hair follicles of the adjacent normal dermis but not into the wound site per se. A significantly higher level of vascular endothelial growth factor was secreted into the CM of pulp cells when compared with dermal fibroblast and keratinocytes. Tubular network formation of endothelial cells and the proliferation of dermal fibroblasts were significantly enhanced by the application of pulp cell CM when compared with control media.Conclusions: Our results show that local injection of pulp cells is effective in enhancing wound healing during the initial proliferative phase, especially through paracrine mechanisms regulating host angiogenesis and proliferation.

Stimulation of Matrix Metalloproteinases by Tumor Necrosis Factor–α in Human Pulp Cell Cultures

2013-03-01

Abstract: Introduction: The purpose of this study was to investigate whether in vitro stimulation of pulp cells leads to increased secretion of matrix metalloproteinases (MMPs) and, if so, to identify which MMPs are affected.Methods: Cells cultured from dental pulp were stimulated with tumor necrosis factor–α (TNF-α) (10 ng/mL) for 24 hours, and lysates were analyzed with an antibody array (Bio-Rad Laboratories, Hercules, CA). The mRNA and protein levels of MMP-3, -10, and -13 were measured by real-time polymerase chain reaction (real-time PCR), enzyme-linked immunosorbent assay (ELISA), Western blot analysis, and zymography. In addition, tumor necrosis factor receptors in the pulp cells were assayed by flow cytometry. The ELISA and real-time PCR results were analyzed by paired t tests.Results: The expression of MMP-3, -10, and -13 was up-regulated in the pulp cells after 24 hours of stimulation with TNF-α (10 ng/mL) as seen in the antibody array, real-time PCR, and ELISA results, but MMP-10 was not detected by Western blotting or casein zymography. Flow cytometry analysis showed that the majority of the pulp cells expressed tumor necrosis factor receptor 1.Conclusions: In regions of inflammation, TNF-α may initiate the degradation of dental connective tissue by activating MMP-3 and MMP-13. These proteins may play an important pathologic role in the inflammation of dental pulp.

Effect of Nifedipine on the Differentiation of Human Dental Pulp Cells Cultured with Mineral Trioxide Aggregate

2013-02-18

Abstract: Introduction: Mineral trioxide aggregate (MTA) can induce differentiation of the dental pulp cells into odontoblast-like cells and generate a dentin-like mineral structure. The mechanisms underlying MTA-induced odontoblastic differentiation in human dental pulp cells (HDPCs) are not completely understood. The purpose of this study was to evaluate the effect of nifedipine as calcium channel blocker on MTA-induced odontoblastic differentiation in HDPCs.Methods: HDPCs extracted from maxillary supernumerary incisors and third molars were directly cultured on MTA with or without nifedipine in the culture medium. Cell growth and expression of odontoblastic differentiation markers were determined by using methyl-thiazol-diphenyl-tetrazolium assay and reverse transcription–polymerase chain reaction analysis, respectively. Phosphorylation of mitogen-activated protein kinase was measured by Western blotting, and calcium deposition was assessed by using alizarin red S staining.Results: MTA at a concentration of 1 mg/mL significantly up-regulated the expression of dentin sialophosphoprotein and dentin matrix protein-1 and enhanced mineralized nodule formation. However, nifedipine attenuated the MTA-induced odontoblastic differentiation in HDPCs. In addition, MTA-induced mineralization was blocked by inhibition of extracellular signal-regulated kinase (ERK), p38, and Jun N-terminal kinase (JNK) by using U0126, SB203580, and SP600125, respectively. Furthermore, phosphorylation of ERK and JNK in response to MTA was inhibited when the medium was supplemented with nifedipine.Conclusions: This study showed that calcium ions released from MTA play an important role in odontoblastic differentiation of HDPCs via modulation of ERK and JNK activation.

Effect of Statins with α-Tricalcium Phosphate on Proliferation, Differentiation, and Mineralization of Human Dental Pulp Cells

2013-02-15

Abstract: Introduction: The aim of this study was to investigate the combined effect of statin and α-tricalcium phosphate (α-TCP) on odontoblastic differentiation of human dental pulp cells and to compare them with mineral trioxide aggregate (MTA).Methods: Experimental cements were prepared with TCP containing simvastatin and atorvastatin. Cell proliferation, cell adherence on a dentin disc, alkaline phosphatase (ALP) activity, expression of osteogenic/odontoblastic markers, and mineralization of the human dental pulp cells on experimental cement and MTA were assessed.Results: The cell growth and ALP activity of TCP containing simvastatin–treated cells was greater than MTA-treated cells. The mineralization and messenger RNA expression of markers (ie, dentin sialophosphoprotein, dentin matrix protein 1, bone morphogenetic protein 2, ALP, and osteonectin) of TCP containing simvastatin– and TCP containing atorvastatin–treated cells were comparable with MTA-treated cells. The enhanced cell proliferation and similar level of ALP of TCP-treated cells compared with the control indicate that α-TCP is an effective osteoconductive material. The differentiation effect observed in TCP containing simvastatin– and TCP containing atorvastatin–treated cells is attributed to the effect of statin.Conclusions: The results suggest that α-TCP can be used for local delivery of statin as a pulp capping material to accelerate reparative dentin formation.

Cytotoxic Effects and Antibacterial Efficacy of a 3-Antibiotic Combination: An In Vitro Study

2013-01-28

Abstract: Introduction: A 3-antibiotic combination (3Mix) is widely used in endodontics for root canal disinfection, particularly in pulp revascularization procedures. However, the cytotoxicity of 3Mix has not been evaluated. The purpose of this study was to determine the cytotoxicity and antibacterial efficacy of 3Mix and each single antibiotic component of 3Mix.Methods: For the cytotoxicity test, human dental pulp cells and apical papilla cells were exposed to either 3Mix or to each single antibiotic component of 3Mix using concentrations of 0.024, 0.097, 0.39, 1.56, 6.25, and 25.00 μg/mL for 1, 3, 5, and 7 days. Cell viability was determined using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. For the antibacterial test, 25.00 μg/mL and 0.39 μg/mL 3Mix or single antibiotic were tested on bacteria isolated from necrotic teeth by measuring bacterial recovery on blood agar.Results: The 0.024-μg/mL concentration of all experimental groups generated the highest dental pulp cell or apical pulp cell viability at all time periods. On day 7, 0.39 μg/mL 3Mix produced more than 90% cell viability; 25.00 μg/mL 3Mix completely eliminated isolated bacteria, whereas 0.39 μg/mL was unable to eradicate all bacteria. However, the overall bacterial reduction was significantly different compared with the control group (P < .01).Conclusions: All drugs except metronidazole induced cytotoxicity on cultured cells. 3Mix generated higher cytotoxicity compared with a single drug. The cytotoxicity increased in a concentration- and time-dependent manner; 0.39 μg/mL 3Mix had less cytotoxicity and was able to significantly reduce bacteria isolated from necrotic teeth.

Evaluation of Root-end Preparation with a New Ultrasonic Tip

Zhengzheng Liu, Deqian Zhang, Qimeng Li, Qiong Xu — 2013-04-15

Abstract: Introduction: This study was conducted to evaluate the effect of a new ultrasonic tip (Jetip) for root-end preparation.Methods: A total of 80 single-rooted teeth were endodontically treated, and the apical 3 mm of the root apex was resected. Teeth were randomly distributed into 2 experimental groups according to the ultrasonic tips used to prepare the root-end cavity. Epoxy resin replicas of root-end surfaces after root-end resection were obtained. A root-end cavity was then prepared with an ultrasonic tip, either Jetip or AS3D. Replicas of the apices were fabricated after the retropreparations, and they were processed for analysis by scanning electron microscopy (SEM) to evaluate the presence of microcracks and the quality of the root-end preparation. The morphologic characteristics of the ultrasonic tip were also assessed by SEM. The time required for root-end preparation was recorded.Results: There were no statistically significant differences between the Jetip and AS3D groups in the mean time for the root-end preparation, the incidence of microcracks, or the quality of the root-end preparation (P > .05). SEM analysis showed that Jetip exhibited smoothed microprojections after the root preparations, whereas the loss of diamond particles was observed in AS3D.Conclusions: Both Jetip and AS3D provided rapid and regular root-end preparations. The cutting efficiencies of both Jetip and AS3D decreased with the number of times the tips were used. The Jetip showed smooth microprojections after root-end preparation, whereas the AS3D tip exhibited the loss of diamond particles.

Success of Ultrasonic Technique in Removing Fractured Rotary Nickel-Titanium Endodontic Instruments from Root Canals and Its Effect on the Required Force for Root Fracture

Hasan Shahabinejad, Amirreza Ghassemi, Lida Pishbin, Arash Shahravan — 2013-04-18

Abstract: Introduction: Fracture of rotary nickel-titanium files is a real concern among endodontists; it affects the long-term prognosis of treatment. Ultrasound is a favorable technique for removing broken files, although it may result in some complications. The aim of this study was to determine the success rate of ultrasonic technique in removing file fragments and to evaluate its influence on the force required to fracture a tooth root.Methods: An in vitro study was carried out on 70 extracted maxillary premolars. In the experimental group a #30/.04 taper Hero file was guided into the canal to break and lodge therein. The lodged file was removed by ultrasonic vibration and use of a dental operating microscope. The canals were instrumented with Hero files by using crown-down technique and then obturated. All the teeth were prepared for mechanical testing in Testometric machine to measure the required force for root fracture. The Fisher exact test and independent two-sample t test were used to analyze data.Results: Ultrasonic technique exhibited a success rate of 80% in removing broken files. Success rate in the roots with file fracture before the curve was 11.5 times more than that of file fracture cases beyond the curve. Other factors such as bypass possibility did not affect success rate. The average time required for removing file fragments was 36.3 ± 7.15 minutes, which did not significantly differ in different file locations within the canal. According to mechanical test results, ultrasonic application did not significantly affect the required force for root fracture. The force required to fracture a root did not significantly differ in various file locations. Vertical fracture in the buccolingual direction (split tooth) was the most incident fracture pattern. Procedural errors observed in this study predominantly included transportation, perforation, and craze line.Conclusions: Ultrasonic technique was successful in removing 80% of fractured rotary files and did not significantly affect the required force for root fracture.

Effect of Asymmetry on the Behavior of Prototype Rotary Triple Helix Root Canal Instruments

Franck Diemer, Jérome Michetti, Jean-Philippe Mallet, Robert Piquet — 2013-03-06

Abstract: Introduction: Two factors affect the choice of instruments for root canal preparation: its ability to achieve the canal's shaping and its safety. These factors depend on the profile of the instrument and the design of its active part. In this study, we tried to assess the role of an asymmetric cross-section on the behavior of the instrument by measuring the stresses generated during the preparation of a simulated canal.Methods: Three 25-mm-long, 0.06 taper, ISO size #30 helical nickel-titanium instruments were tested. The first HeroShaper (Micro-Mega, Besançon, France) used had a symmetric triple helix section (H0). The others, based on the HeroShaper design, had a constant asymmetry of 4/100 mm (H4) or 6/100 mm (H6). Six canals were prepared using each instrument, and the experimental conditions (ie, speed and movement) were the same for each sample. A dynamometer with a sensitivity of 0.1 N recorded the stresses transmitted by the instruments.Results: Torque and apical force increased proportionally with instrument penetration. At the end of the preparations, the axial stress averaged 7.39 N for the symmetric instrument and 5.92 and 5.15 N for the asymmetric instruments, which indicated a significant statistical analysis of variance (P < .001). The average torque was low (1.05–1.13 N.cm), which indicated a nonsignificant statistical analysis of variance (P = .2385).Conclusions: In this study, axial stresses decreased, but torque did not change with an asymmetric triple helix cross-section.

Long-term Dose- and Time-dependent Effects of Endodontic Sealers in Human In Vitro Osteoclastogenesis

2013-03-06

Abstract: Introduction: This study evaluates the concentration and time-dependent effects of endodontic sealers' extracts (AH Plus [Dentsply DeTrey, Konstanz, Germany], GuttaFlow [Roeko, Colténe/Whaledent, Germany], Tubliseal [Kerr/Sybron, Romulus, MI], Sealapex [Kerr/Sybron, Romulus, MI], and RealSeal [SybronEndo, Orange, CA]) in the differentiation and function of both unstimulated and stimulated osteoclast precursors, simulating, respectively, immature/undifferentiated precursors and cells undergoing osteoclastogenesis.Methods: The sealers were mixed according to the manufacturers' instructions, freshly extracted with culture medium (1.3 cm2/mL, 24 hours, 37°C, 5% CO2/air), and diluted (1:20, 1:100, 1:500, and 1:2500). Human peripheral blood mononuclear cells were used as osteoclast precursor cells. After overnight attachment, peripheral blood mononuclear cell cultures were exposed to the sealers' extracts during 21 days in the absence (unstimulated) or presence (stimulated) of recombinant macrophage colony-stimulating factor and receptor for the activation of nuclear factor-κB ligand. Cultures performed in the absence of the extracts were used as the control. Cultures were characterized for osteoclastic differentiation and function.Results: Extracts caused mostly inhibitory effects on osteoclastic cells, both in unstimulated and stimulated conditions, which were reflected by a decrease in tartrate-resistant acid phosphatase activity, the presence of actin rings, vitronectin and calcitonin receptors, the calcium phosphate resorbing ability, and the expression of osteoclastic genes. Also, the extracts induced alterations in the relative contribution of some intracellular signaling pathways involved in osteoclastogenic events. The sealers differed in the dose- and time-dependent profile. An adaptive cell response was noticed for the inhibitory effects after long-term exposure.Conclusions: Endodontic sealers affect the osteoclastic differentiation and activity, which is followed by an adaptive cell response. Our results suggest that the deleterious effect in the bone periapical tissues observed with the root canal sealers might involve, at least partially, a direct effect on the osteoclastic cells.

Non-Hodgkin Lymphoma in the Periapical Region of a Mandibular Canine

Elismauro Francisco Mendonça, Thiago Oliveira Sousa, Carlos Estrela — 2013-03-14

Abstract: Introduction: Images and clinical characteristics of some lesions may lead to misinterpretations between diseases of endodontic and non-endodontic origin. Non-Hodgkin lymphomas occur in extranodal sites and may arise primarily in the oral cavity or jaws.Methods: A case of lymphoma associated with the roots of teeth #21–23 in a 38-year-old woman is described. The patient sought dental care because of continuous discomfort at palpation of the periapical area of teeth #21–23, which had been treated endodontically. Radiographic and clinical exams revealed no inflammatory signs. The patient reported losing 24 pounds in the last 2 months. Intraoral examination revealed an expansion of the buccal surface, a solid hard mass, and normal mucosa color.Results: Conventional radiographs showed a diffuse bone radiolucent area, and cone-beam computed tomography images confirmed destruction of the buccal cortical bone, which was suggestive of malignancy. Incisional biopsy was performed, and microscopy showed a lymphoproliferative lesion of uncertain nature with pleomorphic lymphocyte-like round cells, hyperchromatic nuclei, and atypical mitoses. Immunohistochemistry was used to investigate the nature of these cells and the type of lymphoproliferative disorder, and results showed an area of diffuse large B-cell lymphoma.Conclusions: Non-Hodgkin lymphoma should be part of the differential diagnosis of other jaw lesions such as apical periodontitis. The patient was treated with chemotherapy and did not report any abnormalities after 2 years of treatment.

Associate Registry

2013-06-01

Editorial Board

2013-06-01

Journal of Endodontics

Response of Human Dental Pulp Capped with Biodentine and Mineral Trioxide Aggregate

Maxillary Sinus and Posterior Teeth: Accessing Close Relationship by Cone-beam Computed Tomographic Scanning in a Brazilian Population

Altered Coronal Tissue of the Human Dental Pulp in Chronic Hepatitis C Virus Infected Patients

The Critical Apical Diameter to Obtain Regeneration of the Pulp Tissue after Tooth Transplantation, Replantation, or Regenerative Endodontic Treatment

Ketoprofen Inhibits Expression of Inflammatory Mediators in Human Dental Pulp Cells

Adenosine Monophosphate–activated Protein Kinase/Mammalian Target of Rapamycin–dependent Autophagy Protects Human Dental Pulp Cells against Hypoxia

Bioactivity of Calcium Aluminate Endodontic Cement

Hypotonic-induced Stretching of Plasma Membrane Activates Transient Receptor Potential Vanilloid Channels and Sodium–Calcium Exchangers in Mouse Odontoblasts

Local Injection of Pulp Cells Enhances Wound Healing during the Initial Proliferative Phase through the Stimulation of Host Angiogenesis

Stimulation of Matrix Metalloproteinases by Tumor Necrosis Factor–α in Human Pulp Cell Cultures

Effect of Nifedipine on the Differentiation of Human Dental Pulp Cells Cultured with Mineral Trioxide Aggregate

Effect of Statins with α-Tricalcium Phosphate on Proliferation, Differentiation, and Mineralization of Human Dental Pulp Cells

Cytotoxic Effects and Antibacterial Efficacy of a 3-Antibiotic Combination: An In Vitro Study

Evaluation of Root-end Preparation with a New Ultrasonic Tip

Success of Ultrasonic Technique in Removing Fractured Rotary Nickel-Titanium Endodontic Instruments from Root Canals and Its Effect on the Required Force for Root Fracture

Effect of Asymmetry on the Behavior of Prototype Rotary Triple Helix Root Canal Instruments

Long-term Dose- and Time-dependent Effects of Endodontic Sealers in Human In Vitro Osteoclastogenesis

Non-Hodgkin Lymphoma in the Periapical Region of a Mandibular Canine

Associate Registry

Editorial Board

Table of Contents