Journal of Endodontics

Frequency and Distribution of Radiolucent Jaw Lesions: A Retrospective Analysis of 9,723 Cases

Tyler Koivisto, Walter R. Bowles, Michael Rohrer — 2012-04-16

Abstract: Objectives: Practitioners should be aware of the occurrence rate and usual location of radiolucent jaw lesions. The aims of this study were to examine the frequency and location of radiolucent jaw lesions, including apical granulomas, apical cysts, keratocystic odontogenic tumors (KOTs), central giant cell lesions (CGCLs), ameloblastomas, and metastatic lesions, that were submitted for biopsy along with associated demographics.Methods: Biopsy diagnoses from 9,723 lesions (submitted between 1992 and 2006) were included in this study. Data on lesion location as well as patient demographics were evaluated.Results: Thirty types of radiolucent jaw lesions were classified. Nonhealing apical granulomas (40.4%) and cysts (33.1%) occurred at similar rates and together totaled 73% of all biopsied lesions. The majority of reported granulomas and cysts occurred in the anterior maxilla (>36% in each category). The frequency of KOTs (8.8%), CGCLs (1.3%), ameloblastomas (1.2%), and metastatic lesions (<1%) are to be noted along with their location, which was predominately in the posterior mandible. The occurrence of apical cysts, ameloblastomas, KOTs, and metastatic lesions were seen slightly more in men, at 56%, 54%, 55%, and 68%, respectively. The occurrence of CGCLs was seen slightly more in women at 56%, whereas apical granulomas were equally present in men and women.Conclusions: Most nonhealing lesions submitted for biopsy were classified as granulomas or cysts (73%) often from the anterior maxillary jaw. Nonhealing radiolucent jaw lesions other than granulomas or cysts were reported over 20% of the time and may have more severe pathological implications, suggesting the value of differential diagnoses.

Effect of Platelet Concentrate on Quality of Life after Periradicular Surgery: A Randomized Clinical Study

Massimo Del Fabbro, Valentina Ceresoli, Alessandra Lolato, Silvio Taschieri — 2012-04-16

Abstract: Introduction: Control of postoperative discomfort might enhance the patient’s quality of life and treatment acceptance. The aim of the present randomized single-blind study was to evaluate whether the use of platelet concentrate during endodontic surgery might have a favorable impact on pain and other factors related to patient’s quality of life during the first week after surgery.Methods: Eighteen patients with periapical lesion were treated with modern endodontic surgical procedure (control group). In another 18 patients, in adjunct to surgical procedure, platelet concentrate was applied on the root end in liquid form, within the bone defect in clot form, and over the suture in liquid form (test group). All patients completed a questionnaire for evaluation of main symptoms and daily activities during the first week after surgery. The outcomes of the questionnaires of the 2 groups were statistically compared.Results: The test group showed significantly less pain and swelling, fewer analgesics taken, and improved functional activities as compared with the control group.Conclusions: The adjunct of platelet concentrate to the endodontic surgical procedure produced significant beneficial effect to patients’ quality of life during the early postoperative stage.

Correlation between Clinical/Radiographic Features and Inflammatory Cytokine Networks Produced by Macrophages Stimulated with Endodontic Content

2012-04-20

Abstract: Introduction: Macrophages are highly activated by endodontic contents. This study investigated the correlation between different clinical signs/symptoms and radiographic features according to the levels of interleukin (IL)-1β, tumor necrosis factor α (TNF-α), IL-6, IL-10, prostaglandin E2 (PGE2), and their networks produced by endodontic content–stimulated macrophages collected from primary endodontic infection with apical periodontitis (PEIAP).Methods: Samples were taken from 21 root canals with PEIAP by using paper points. The presence of exudate (EX), pain on palpation (POP), tenderness to percussion (TTP), and the size of the radiographic lesion (SRL) were recorded. Polymerase chain reaction (16S rDNA) was used for bacterial detection and limulus amebocyte lysate (LAL) assay for endotoxin measurement. Raw 264.7 macrophages were stimulated with bacterial contents during 24 hs. The amounts of IL-1β, TNF-α, IL-6, IL-10 and PGE2 were measured by enzyme-linked immunosorbent assay. Log-based data were correlated by multiple logistic regression (P < .05).Results: Bacteria and endotoxin were detected in 100% of the samples. IL-6 and TNF-α were positively correlated with SRL and EX, respectively (P < .05). Clinical signs/symptoms and radiographic findings were set as dependent variables for EX-positive correlations between PGE2, IL-1β, and TNF-α (P < .05), whereas IL-6 and PGE2 were positively correlated to each other in POP but negatively correlated in SRL (P < .05). When POP and TTP-POP were set as dependent variables, different cytokine networks were found.Conclusions: Our findings suggest different roles for each cytokine in the development of apical periodontitis, whose effects of overlapping networks depend on the signs/symptoms and radiographic features found in endodontic infection.

Differential Expression of MicroRNAs in Normal and Inflamed Human Pulps

Sheng Zhong, Shaoping Zhang, Eric Bair, Salvador Nares, Asma A. Khan — 2012-04-16

Abstract: Introduction: MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression via posttranscriptional repression. They are critical to normal cellular function, and bioinformatic predictions indicate that at least one third of all messenger RNAs might be regulated by miRNAs. Although both the innate and adaptive immune responses are known to be regulated by miRNAs, their role in regulating endodontic disease has yet to be explored. The purpose of this study was to examine the differential expression of miRNAs in normal and inflamed human dental pulps and to explore their functional gene targets.Methods: After obtaining informed consent, we collected normal and inflamed human pulps (N = 30). Microarray and molecular biology techniques were then used for gene profiling and identifying functional gene targets.Results: Of the 335 human miRNAs identified in the pulp tissues, 3 miRNAs, miR-150∗, miR-584, and miR-766, were significantly up-regulated in inflamed pulps as compared with normal pulps (P < .003). Thirty-three miRNAs were down-regulated in the inflamed pulps (P < .003). The false discovery rate for these findings is estimated to be approximately 5%. The potential gene targets for these miRNAs include proinflammatory cytokines as well as other key mediators of the immune and inflammatory response to infection.Conclusions: Our data identify differential expression of miRNAs in healthy and diseased human dental pulps. These findings highlight the intricate and specific roles of miRNA in inflammation and immunity, both of which are key aspects of pulpal pathology.

Comparative Evaluation of 1.8 mL and 3.6 mL of 2% Lidocaine with 1:200,000 Epinephrine for Inferior Alveolar Nerve Block in Patients with Irreversible Pulpitis: A Prospective, Randomized Single-blind Study

Vivek Aggarwal, Mamta Singla, Sanjay Miglani, Sarita Kohli, Sandeep Singh — 2012-03-05

Abstract: Introduction: There is a decrease in the anesthetic efficacy of inferior alveolar nerve blocks in patients with irreversible pulpitis. It was hypothesized that the increasing the volume of anesthetic solution may improve the success rates of dental pulp anesthesia in patients with pulpal pain.Methods: Fifty-five adult volunteers, actively experiencing pain, participated in this prospective, randomized, single-blind study. The patients were divided into 2 groups on a random basis and received an inferior alveolar nerve block with either 1.8 mL or 3.6 mL of 2% lidocaine with 1:200,000 epinephrine. Endodontic access preparation was initiated after 15 minutes of the initial IANB. Pain during treatment was recorded using the Heft-Parker visual analog scale (HP VAS). The primary outcome measure, and the definition of “success,” was the ability to undertake pulp access and canal instrumentation with no or mild pain (HP VAS score <55 mm). Statistical analysis was performed using the chi-square test.Results: All patients included in the final analysis had profound lip anesthesia. There were no significant differences in sex, age, or preoperative pain scores of the experimental groups. IANBs of 1.8 mL lidocaine with epinephrine had a success rate of 26%, whereas the administration of 3.6 mL had a 54% success rate. The difference was statistically significant.Conclusions: Increasing the volume of 2% lidocaine to 3.6 mL improved the success rate as compared with 1.8 mL but did not give a clinical success rates of 100%.

Simvastatin Alleviates the Progression of Periapical Lesions by Modulating Autophagy and Apoptosis in Osteoblasts

2012-04-09

Abstract: Introduction: Autophagy is a process for recycling intracellular organelles as a survival mechanism. Apoptosis has important biological roles in the pathogenesis of many diseases. This study elucidated the effect of simvastatin on autophagy/apoptosis in MC3T3E1 murine osteoblastic cells and also the significance of this action on the progression of induced rat apical periodontitis.Methods: We examined the H2O2-stimulated expression of LC3-II (an autophagy marker) and poly (adenosine phosphate ribose) polymerase (PARP) fragmentation (an apoptosis marker) in MC3T3E1 by Western analysis. In a rat model of induced apical periodontitis, the relation between disease progression and osteoblastic expression of Beclin-1 (an autophagy marker) and terminal deoxyuridine triphosphate nick end-labeling (an apoptosis marker) was studied by radiographic and immunohistochemistry analyses.Results: Western blot showed elevated levels of LC3-II and PARP cleavage after H2O2 treatment. An autophagy inhibitor 3-methyladenine promoted whereas rapamycin (an autophagy enhancer) diminished H2O2-induced PARP cleavage. Simvastatin enhanced H2O2-induced LC3-II formation and simultaneously decreased PARP fragmentation. Radiography and immunohistopathology demonstrated that simvastatin reduced the number of apoptotic osteoblasts and the extension of periapical lesions in rats. The number of Beclin-1–synthesizing osteoblasts also increased markedly after simvastatin treatment.Conclusions: We found a negative relation between autophagy and apoptosis in osteoblastic cells. In addition, simvastatin suppressed apoptosis and enhanced autophagy both in vitro and in vivo. Our data implied that simvastain might alleviate the progression of apical periodontitis by promoting autophagy to protect osteoblasts from turning apoptotic.

The Levels of Vascular Endothelial Growth Factor and Bone Morphogenetic Protein 2 in Dental Pulp Tissue of Healthy and Diabetic Patients

2012-04-26

Abstract: Introduction: Vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP 2) are growth factors (GFs) identified within the dentine-pulp complex and involved into the cellular events connected to the pulp-healing response. It is well established that the expression of these GFs is increased in different tissues in diabetes mellitus. Because there are no data concerning the levels of VEGF and BMP 2 in human dental pulp, the aim of present study was to quantify VEGF and BMP 2 levels in intact dental pulp and dental pulp that underwent reactive dentinogenesis in healthy and diabetic human subjects.Methods: The study was conducted on 28 healthy and 28 subjects with controlled diabetes type II who underwent pulp extirpation as a part of prosthetic rehabilitation. Pulp were collected from intact teeth and teeth treated by indirect pulp capping. The levels of VEGF and BMP 2 were determined in the pulp tissue lysates with enzyme-linked immunosorbent assay.Results: The levels of VEGF and BMP 2 were significantly higher in intact teeth pulp of diabetic than in healthy subjects. The concentrations of these GFs were significantly lowered in teeth with indirect pulp capping both in healthy and diabetic persons. Furthermore, VEGF and BMP 2 levels were in strong positive correlation.Conclusions: Similar changes in the levels of VEGF and BMP 2 in intact and treated teeth of healthy and diabetic patients could be suggestive of associated roles of these GFs in responses of healthy and diabetic dental pulp.

Lysyl Oxidase and the Lysyl Oxidase–like Protein Modulate Odontoblastic Differentiation of Human Dental Pulp Cells

Eun-Cheol Kim, Hwa-Jeong Lee, Youngho Kim — 2012-04-23

Abstract: Introduction: The lysyl oxidase (LOX) family is an emerging family of amine oxidases responsible for the formation of collagen fibrils in the extracellular matrix. To date, 5 LOX family genes have been identified in humans, encoding LOX and LOX-like proteins (LOXL, LOXL2, LOXL3, and LOXL4). The goal of this study was to evaluate the expression and function of the LOX family genes in odontoblastic differentiation of human dental pulp (HDP) cells.Methods: Expression of the LOX family genes was assessed by reverse transcriptase polymerase chain reaction analysis, and the amine oxidase activity of HDP cells was evaluated by peroxidase-coupled fluorometric assays. Mineral nodule formation and expression of odontoblastic marker genes were assessed in the presence and absence of specific small interfering RNAs (siRNAs) of the LOX family genes.Results: Among the LOX family genes, only LOX and LOXL showed prominent expression during odontoblastic differentiation of HDP cells. Suppression of LOX and LOXL expression by siRNA-induced interference substantially decreased the amine oxidase activity of the differentiating HDP cells. Furthermore, interference of LOX and LOXL expression inhibited mineral nodule formation and expression of odontoblastic marker genes during odontoblastic differentiation of HDP cells.Conclusions: These findings show for the first time that the LOX- and LOXL-mediated organization of collagen fibrils in extracellular matrices of HDP cells might be an important regulator for odontoblastic differentiation of HDP cells.

Regulation of Vascular Cell Adhesion Molecule-1 in Dental Pulp Cells by Interleukin-1β: The Role of Prostanoids

2012-04-13

Abstract: Introduction: Vascular cell adhesion molecule (VCAM-1) plays a critical role in the inflammatory processes by stimulating the recruitment, extravasation, and migration of leukocytes. Its expression and regulation in the dental pulp is not well elucidated.Methods: Primary dental pulp cells were exposed to prostaglandin E2 (PGE2), prostaglandin F2α (PGF2α), or interleukin 1β (IL-1β) with/without aspirin. VCAM-1 messenger RNA expression was analyzed by reverse transcriptase–polymerase chain reaction. Soluble VCAM-1 (sVCAM-1) in the culture medium was determined by enzyme-linked immunosorbent assay, and the number of viable cells was estimated by (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay.Results: IL-1β induced VCAM-1 gene expression of pulp cells. IL-1β also stimulated sVCAM-1 production. The IL-1β–induced sVCAM-1 production was not inhibited but rather enhanced by aspirin, a cyclooxygenase (COX) inhibitor. PGE2 and PGF2α decreased the VCAM-1 expression and sVCAM-1 production of pulp cells. U0126 (1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene), a mitogen-activated protein kinase kinase (MEK) inhibitor, attenuated IL-1β–induced sVCAM-1 production. However, no marked cytotoxicity was noted in these experimental conditions as analyzed by MTT assay.Conclusions: IL-1β may be involved in the pulpal inflammatory processes via stimulation of VCAM-1 expression and sVCAM-1 production. This event is not mediated by COX activation and prostanoid production but is associated with MEK signaling. PGE2 and PGF2α may potentially regulate inflammatory processes by the inhibition of VCAM-1.

Cytidine-Phosphate-Guanosine Oligonucleotides Induce Interleukin-8 Production through Activation of TLR9, MyD88, NF-κB, and ERK Pathways in Odontoblast Cells

2012-04-06

Abstract: Introduction: Odontoblasts are involved in innate immunity against invading microorganisms. However, the mechanisms of host inflammatory responses to bacterial DNA in odontoblasts are not fully understood. The purpose of this study was to investigate whether microbial cytidine-phosphate-guanosine (CpG) DNA influences interleukin-8 (IL-8) expression in odontoblasts and the signaling pathways involved.Methods: The effect of CpG oligonucleotide (CpG ODN) on IL-8 mRNA and protein expression levels in the mouse odontoblast-like cell line MDPC-23 was investigated by real-time polymerase chain reaction (PCR) analysis and enzyme-linked immunosorbent assay (ELISA). Whether Toll-like receptor 9 (TLR9), myeloid differentiation marker 88 (MyD88), nuclear factor kappa B (NF-κB), or mitogen-activated protein kinase (MAPK) pathways were involved in the CpG ODN–induced IL-8 expression was determined by examined real-time PCR, ELISA, and luciferase activity assay. Extracellular signal-regulated kinase (ERK) activation and TLR9 protein expression were measured by Western blot analysis.Results: Exposure to CpG ODN induced significant up-regulation of IL-8 mRNA and protein in MDPC-23 cells. CpG ODN–induced IL-8 up-regulation was attenuated by TLR9 inhibitor (chloroquine) and MyD88 inhibitory peptide. CpG ODN also increased the expression of TLR9 mRNA and protein in MDPC-23 cells. Treatment of MDPC-23 cells with NF-κB inhibitors (pyrrolidine dithiocarbamate), IκBα phosphorylation inhibitors (Bay 117082), or IκB protease inhibitor (L-1-tosylamido-2-phenylethyl chloromethyl ketone) decreased CpG ODN–induced IL-8 expression. Furthermore, stimulation of cells with CpG ODN enhanced κB-luciferase activity, and the activity was diminished by the overexpression of dominant negative mutants of MyD88 and IκBα. In addition, CpG ODN–induced IL-8 expression was markedly suppressed by U0126, but not by SB203580 and SP600125. Moreover, CpG ODN activated ERK phosphorylation in a time-dependent manner.Conclusions: These data demonstrate that CpG ODN–induced IL-8 expression was mediated through TLR9, MyD88, NF-κB, and ERK pathways in MDPC-23 cells and suggest a possible role for the CpG DNA–mediated immune response in odontoblasts with involvement of TLR9, MyD88, and ERK pathways in this process.

Anandamide Induces Matrix Metalloproteinase-2 Production through Cannabinoid-1 Receptor and Transient Receptor Potential Vanilloid-1 in Human Dental Pulp Cells in Culture

Keiko Miyashita, Tohru Oyama, Tetsuya Sakuta, Masayuki Tokuda, Mitsuo Torii — 2012-04-13

Abstract: Introduction: Anandamide (N-arachidonoylethanolamine [AEA]) is one of the main endocannabinoids. Endocannabinoids are implicated in various physiological and pathologic functions, inducing not only nociception but also regeneration and inflammation. The role of the endocannabinoid system in peripheral organs was recently described. The aim of this study was to investigate the effect of AEA on matrix metalloproteinase (MMP)-2 induction in human dental pulp cells (HPC).Methods: We examined AEA-induced MMP-2 production and the expression of AEA receptors (cannabinoid [CB] receptor-1, CB2, and transient receptor potential vanilloid-1 [TRPV1]) in HPC by Western blot. MMP-2 concentrations in supernatants were determined by enzyme-linked immunosorbent assay. We then investigated the role of the AEA receptors and mitogen-activated protein kinase in AEA-induced MMP-2 production in HPC.Results: AEA significantly induced MMP-2 production in HPC. HPC expressed all 3 types of AEA receptor (CB1, CB2, and TRPV1). AEA-induced MMP-2 production was blocked by CB1 or TRPV1 antagonists and by small interfering RNA for CB1 or TRPV1. Furthermore, c-Jun N-terminal kinase inhibitor also reduced MMP-2 production.Conclusions: We demonstrated for the first time that AEA induced MMP-2 production via CB1 and TRPV1 in HPC.

Isolation and Identification of CXCR4-positive Cells from Human Dental Pulp Cells

Long Jiang, Wei-Wei Peng, Li-Fen Li, Ya Yang, Ya-Qin Zhu — 2012-04-09

Abstract: Introduction: In previous studies, we found expression of stromal cell–derived factor-1α (SDF-1α)/CXC chemokine receptor 4 (CXCR4) in human dental pulp and the SDF-1α–CXCR4 axis might play a role in the recruitment of CXCR4-positive dental pulp cells (CXCR4+ DPCs) toward the damaged sites. However, the specific function of CXCR4+ DPCs in the injured dental pulp was still unknown. The purpose of this study was to isolate CXCR4+ DPCs from dental pulp cells in vitro to pave the way for further study of their characteristics.Methods: CXCR4+ DPCs were isolated with magnetic-activated cell sorting (MACS). Freshly isolated CXCR4+ DPCs were identified by immunohistochemistry with light microscopy or confocal microscopy. Then the phenotypes CXCR4, stromal cell surface marker-1 (STRO-1), CD146, and CD34 in 3 groups (ie, CXCR4+ DPCs, CXCR4− DPCs, or non-sorted DPCs) were analyzed by flow cytometry after they were cultured and expanded in vitro.Results: The results indicated the isolated subpopulation of DPCs was enriched with CXCR4+ DPCs, and the positive rates of STRO-1 and CD146 in CXCR4+ DPCs group were higher than CXCR4− DPCs or non-sorted DPCs groups (P < .05). There was no expression of CD34 in each group.Conclusions: We can isolate CXCR4+ DPCs from DPCs with MACS and identify them by immunohistochemistry and flow cytometry.

Changes in Proliferation and Osteogenic Differentiation of Stem Cells from Deep Caries In Vitro

Dandan Ma, Jie Gao, Jing Yue, Wenjuan Yan, Fuchun Fang, Buling Wu — 2012-03-26

Abstract: Introduction: It is suggested that dental pulp stem cells are involved in tooth regeneration and play an important role in maintaining pulp homeostasis. Previously, normal dental pulps were more widely used for experimental models than carious dental pulps. The aim of this study was to isolate and culture the dental pulp stem cells from carious and normal teeth and to evaluate stem cell parameters.Methods: Pulp tissues were obtained and dissociated from normal and carious teeth. Single-cell suspensions were seeded into 6-well plates and purified by collecting multiple colonies. Normal dental pulp stem cells (DPSCs) and carious dental pulp stem cells (CDPSCs) were compared for morphologic appearance and for their capacity to differentiate into 3 lineages. Colony-forming and MTT assays, cell cycle analysis, gene expression, and alkaline phosphatase activity were also evaluated.Results: Stem cells were cultured successfully from normal and carious dental pulps. CDPSCs displayed increased proliferation ability compared with DPSCs. CDPSCs also showed enhanced ALP activity, mineralization ability, and expression of osteogenesis/dentinogenesis-related genes. All cultures differentiated into 3 cell types.Conclusions: Our data suggest that caries as a local microenvironment should be taken into account when DPSCs are intended to be used for investigations and application. Furthermore, the mechanism of the underlying changes in cell properties requires further study.

Toll-like Receptor 2 Knockout Mice Showed Increased Periapical Lesion Size and Osteoclast Number

2012-04-30

Abstract: Introduction: The aim of this study was to characterize the formation and progression of experimentally induced periapical lesions in TLR2 knockout (TLR2 KO) mice.Methods: Periapical lesions were induced in molars of 28 wild type (WT) and 27 TLR2 KO mice. After 7, 21, and 42 days, the animals were euthanized, and the mandibles were subjected to histotechnical processing. Hematoxylin-eosin–stained sections were examined under conventional light microscopy for the description of pulpal, apical, and periapical features and under fluorescence microscopy for the determination of the periapical lesion size. The subsequent sections were evaluated by tartrate resistant acid phosphatase histoenzymology (osteoclasts), Brown and Brenn staining (bacteria), and immunohistochemistry (RANK, RANKL, and OPG). Data were analyzed by the Mann-Whitney U and Kruskal-Wallis tests (α = 0.05).Results: The WT group showed significant differences (P < .05) in the periapical lesion size and the osteoclast number between 7 and 42 days and between 21 and 42 days. In the TLR2 KO group, significant differences (P < .05) in the periapical lesion size and the osteoclast number were found between 7 days and the other periods. There was a significant difference (P < .05) between the 2 types of animal regarding the periapical lesion size, which was larger in the TLR2 KO animals. No significant differences (P > .05) were found between WT and TLR2 KO mice related to the pulpal, apical, and periapical features; bacteria localization; and immunohistochemical results (except for RANK expression).Conclusions: TLR2 KO animals developed larger periapical lesions with a greater number of osteoclasts, indicating the important role of this receptor in the host's immune and inflammatory response to root canal and periradicular infection.

Quantitative Determination of High-temperature Requirement Protein A1 and Its Possible Associated Molecules during Induced Reparative Dentin Formation

Xianyu Li, Mi Zhou, Xiaoying Wang, Ran Li, Nana Han, Qi Zhang — 2012-06-01

Abstract: Introduction: The equilibrium of inhibitors and inducers plays an important role in the mineralization of dentin during dentinogenesis. High-temperature requirement protein A1 (HtrA1) is a novel bone mineralization inhibitor involved in physiological and pathological bone formation. However, the expression of HtrA1 in tooth mineralization is unknown. The purpose of the present study was to investigate the localization and quantity of HtrA1 and its possible related molecules during induced reparative dentin formation.Methods: Rats were randomly sacrificed after direct pulp capping on days 0, 7, 14, and 21. Maxillary segments were obtained and routinely prepared for histological analysis, immunohistochemistry, quantum dots–based double immunofluorescence, and CRi’s Nuance imaging system (CRI, Woburn, MA)–based quantitative determination.Results: The square measure values of reparative dentin significantly increased on day 7 and continued to increase until day 21. HtrA1, matrix Gla protein (MGP), nestin, and bone sialoprotein were positively stained and colocalized in the odontoblasts and/or odontoblast-like cells zone and reparative dentin during induced reparative dentin formation. The expressions of HtrA1 and MGP were significantly enhanced after direct pulp capping on day 7 and did not significantly change between days 7, 14, and day 21. Both expressions of HtrA1 and MGP were positively correlated with the square measure values of reparative dentin; however, no correlation was found between the expressions of HtrA1 and MGP.Conclusions: HtrA1 could be observed and might possibly be involved in the process of reparative dentin formation associated with MGP.

Decreased Bacterial Adherence and Biofilm Growth on Surfaces Coated with a Solution of Benzalkonium Chloride

David E. Jaramillo, Alberto Arriola, Kamran Safavi, Luis E. Chávez de Paz — 2012-04-27

Abstract: Introduction: Secondary biofilm formation by oral bacteria after breakdown/fracture of temporary or permanent restorations imposes a challenge to the outcome of root canal treatment. This study focuses on benzalkonium chloride (BAK) coating on dentin or polystyrene surfaces and its influence on the early adhesion and biofilm formation by oral and root canal bacteria.Methods: Microbial adhesion and biofilm growth on surfaces coated with BAK were analyzed qualitatively with a dentin disk model and quantitatively with a mini-flow cell biofilm model. Cell viability and total biovolume were analyzed by the LIVE/DEAD technique. The repelling effect of surfaces coated with BAK was compared with NaOCl. Uncoated surfaces were used as controls.Results: Scanning electron microscope images in the dentin disk model revealed that very sparse biofilms were formed on NaOCl- and BAK-coated dentin surfaces. In contrast, biofilms formed on uncoated dentin were clearly visible as numerous irregularly distributed aggregates of rods and cocci. In the mini-flow cell system, confocal laser scanning microscope analysis confirmed that biofilms formed on NaOCl- and BAK-coated surfaces showed significantly less adhesion (2 hours) and biovolume accumulation (24 and 96 hours) compared with the uncoated controls (P < .01). Furthermore, cell viability assessments showed that on uncoated controls the viability measurements were high (>89%) as well as on BAK-coated surfaces (88% viable cells). However, cell viability was significantly reduced on NaOCl-coated surfaces (59% viable cells).Conclusions: This study illustrates that surface coating with a surfactant solution containing BAK does not cause cell membrane damage but might interfere with cell mechanisms of adhesion. Investigations into the clinical utility of BAK as an antibiofilm medication are warranted.

Residual Activity of Chelating Agents and their Combinations with Cetrimide on Root Canals Infected with Enterococcus faecalis

2012-02-27

Abstract: Introduction: The use of chelating agents in endodontic treatment is required to remove the smear layer and to achieve better disinfection within the root canal system. The aim of this study was to evaluate the residual antimicrobial activity of 17% ethylenediaminetetraacetic acid (EDTA), 7% maleic acid (MA), and 10% lactic acid (LA) alone and combined with 0.2% cetrimide (CTR) on infected root canals with Enterococcus faecalis.Methods: Biofilms of E. faecalis were grown in uniradicular roots for 4 weeks. After preparation the roots were randomly divided into 6 groups (n = 15) according to the final irrigation regimen as follows: 5 mL of 17% EDTA; 5 mL of 17% EDTA + 0.2% CTR; 5 mL of 7% MA; 5 mL of 7% MA + 0.2% CTR; 5 mL of 10% LA; and 5 mL of 10% LA + 0.2% CTR. Samples were collected for 60 days to denote the presence of bacterial growth. Fisher and Pearson χ2 tests were applied to compare the percentages of specimens without E. faecalis regrowth at all the time periods.Results: There were significant differences in bacterial regrowth between the groups with and without CTR. There were not significant differences over time among the 3 groups with CTR or among the 3 without CTR.Conclusions: The residual activity against E. faecalis of 7% MA + 0.2% CTR, 17% EDTA + 0.2% CTR, and 10% LA + 0.2% CTR was greater than the use of chelating agents alone.

Effects of Calcium Silicate–based Materials on Collagen Matrix Integrity of Mineralized Dentin

2012-02-02

Abstract: Introduction: Calcium silicate–based materials (CSMs) are used in various endodontic procedures. The present study examined whether prolonged contact of mineralized dentin with recently commercialized versions of these materials adversely affects dentin collagen matrix integrity.Methods: Dentin slabs prepared from extracted human third molars (7 × 3 × 0.3 mm) were divided into 3 groups on the basis of the material to which dentin was exposed (MTA Plus, Biodentine, untreated control dentin slabs) and the time period of exposure (24 hours, 1, 2, and 3 months; n = 6). Hydroxyproline assay was performed on each group’s supernatant to quantify the collagen extraction amounts of each group per time period. Data were analyzed with two-factor repeated-measures analysis of variance and Holm-Sidak pair-wise comparisons (α = 0.05) to determine the effects of material and aging time on collagen extraction. Dentin slabs from the 3 months of aging group were demineralized for transmission electron microscopy examination of collagen matrix ultrastructural changes.Results: Material (P = .002), aging time (P < .001), and their interactions (P = .007) significantly affected the amount of hydroxyproline (pg/mg of mineralized dentin) extracted from mineralized dentin and were significantly correlated by power regression models. Collagen degradation was identified from the surface of dentin slabs that were in direct contact with CSMs.Conclusions: Prolonged contact of mineralized dentin with CSMs has an adverse effect on the integrity of the dentin collagen matrix. However, the amount of collagen extracted was limited to the contact surface. Clinicians can continue to apply CSMs in endodontic procedures; however, caution is advised when these materials are applied to thin dentinal walls.

Effect of Ultrasonic Activation on pH and Calcium Released by Calcium Hydroxide Pastes in Simulated External Root Resorption

2012-04-26

Abstract: Introduction: The purpose of this study was to analyze the influence of ultrasonic activation of calcium hydroxide (CH) pastes on pH and calcium release in simulated external root resorptions.Methods: Forty-six bovine incisors had their canals cleaned and instrumented, and defects were created in the external middle third of the roots, which were then used for the study. The teeth were externally made impermeable, except for the defected area, and divided into the following 4 groups containing 10 samples each according to the CH paste and the use or not of the ultrasonic activation: group 1: propylene glycol without ultrasonic activation, group 2: distilled water without ultrasonic activation, group 3: propylene glycol with ultrasonic activation, and group 4: distilled water with ultrasonic activation. After filling the canals with the paste, the teeth were restored and individually immersed into flasks with ultrapure water. The samples were placed into other flasks after 7, 15, and 30 days so that the water pH level could be measured by means of a pH meter. Calcium release was measured by means of an atomic absorption spectrophotometer. Six teeth were used as controls. The results were statistically compared using the Kruskal-Wallis and Mann-Whitney U tests (P < .05).Results: For all periods analyzed, the pH level was found to be higher when the CH paste was activated with ultrasound. Calcium release was significantly greater (P < .05) using ultrasonic activation after 7 and 30 days.Conclusions: The ultrasonic activation of CH pastes favored a higher pH level and calcium release in simulated external root resorptions.

Comparison of the Cleaning Efficacy of Different Final Irrigation Techniques

2012-04-26

Abstract: Introduction: The aim of this study was to evaluate the removal of dentin debris from artificially made grooves in standardized root canals by 6 different final irrigation techniques.Methods: Conventional syringe irrigation, manual dynamic activation (MDA) with tapered or nontapered gutta-percha (GP) cones, the Safety Irrigator system, continuous ultrasonic irrigation (CUI), and apical negative pressure (ANP) irrigation were tested ex vivo in 20 root canals with a standardized, debris-filled groove in the apical portion of one canal wall. After each irrigation procedure, the groove was photographed, and the residual amount of dentin debris was scored.Results: There was no significant difference between the MDA with a nontapered GP cone, the Safety Irrigator, and the ANP irrigation. These techniques produced better cleaning efficacy than syringe irrigation (P < .005) but significantly worse than the MDA with a tapered cone (P < .05). CUI was significantly better than all the other techniques tested in this study (P < .001).Conclusions: CUI was the most effective technique in dentin debris removal from the apical irregularities, and syringe irrigation alone was the least effective. MDA technique was more effective with a tapered GP cone than with a nontapered one.

Evaluation of Radiopacity, pH, Release of Calcium Ions, and Flow of a Bioceramic Root Canal Sealer

2012-04-06

Abstract: Introduction: The aim of the present study was to evaluate the physicochemical properties of a bioceramic root canal sealer, Endosequence BC Sealer. Radiopacity, pH, release of calcium ions (Ca2+), and flow were analyzed, and the results were compared with AH Plus cement.Methods: Radiopacity and flow were evaluated according to ISO 6876/2001 standards. For the radiopacity analysis, metallic rings with 10-mm diameter and 1-mm thickness were filled with cements. The radiopacity value was determined according to radiographic density (mm Al). The flow test was performed with 0.05 mL of cement placed on a glass plate. A 120-g weight was carefully placed over the cement. The largest and smallest diameters of the disks formed were measured by using a digital caliper. The release of Ca2+ and pH were measured at periods of 3, 24, 72, 168, and 240 hours with spectrophotometer and pH meter, respectively. Data were analyzed by analysis of variance and Tukey test (P < .05).Results: The bioceramic endodontic cement showed radiopacity (3.84 mm Al) significantly lower than that of AH Plus (6.90 mm Al). The pH analysis showed that Endosequence BC Sealer showed pH and release of Ca2+ greater than those of AH Plus (P < .05) during the experimental periods. The flow test revealed that BC Sealer and AH Plus presented flow of 26.96 mm and 21.17 mm, respectively (P < .05).Conclusions: Endosequence BC Sealer showed radiopacity and flow according to ISO 6876/2001 recommendations. The other physicochemical properties analyzed demonstrated favorable values for a root canal sealer.

Self-Adjusting File Cleaning-Shaping-Irrigation System Optimizes the Filling of Oval-shaped Canals with Thermoplasticized Gutta-percha

2012-04-19

Abstract: Introduction: This study aimed to compare the filling ability of carrier-based thermoplasticized gutta-percha in flat-oval canals prepared using either rotary ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland) or the Self-Adjusting File system (SAF) (ReDent-Nova, Ra'anana, Israel).Methods: Thirteen pairs of mandibular incisors were selected from a random collection. The teeth in each pair had single root canals with a flat-oval cross-section and similar sizes and dimensions. Teeth from each pair were randomly assigned to 1 of 2 experimental groups. One group was instrumented using the ProTaper NiTi system, whereas the SAF system was used in the other. Root filling was performed with Thermafil obturators (Dentsply Tulsa Dental Products, Tulsa, OK), and teeth were sectioned at 6, 5, 4, and 3 mm from the apex; the cut surface was subjected to morphometric measurement to establish the percent gutta-percha–filled area (PGFA) for each section. The Wilcoxon matched-pairs signed rank test was used to assess the effect of the 2 preparation methods on the PGFA.Results: The median PGFA in the ProTaper group was 77.5%, whereas the median PGFA was 90.5% in the SAF group (P < .05). In the SAF-instrumented group, 17.8% of the specimens had a PGFA ≥95% compared with only 5.8% of the ProTaper-instrumented specimens (P < .05).Conclusions: Instrumentation of the flat-oval canals with the SAF system led to a significantly higher PGFA compared with ProTaper instrumentation with syringe and needle irrigation.

Apically Extruded Debris with Reciprocating Single-File and Full-sequence Rotary Instrumentation Systems

Sebastian Bürklein, Edgar Schäfer — 2012-04-09

Abstract: Introduction: The purpose of this in vitro study was to assess the amount of apically extruded debris using rotary and reciprocating nickel-titanium instrumentation systems.Methods: Eighty human mandibular central incisors were randomly assigned to 4 groups (n = 20 teeth per group). The root canals were instrumented according to the manufacturers’ instructions using the 2 reciprocating single-file systems Reciproc (VDW, Munich, Germany) and WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) and the 2 full-sequence rotary Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) instruments. Bidistilled water was used as irrigant. The apically extruded debris was collected in preweighted glass vials using the Myers and Montgomery method. After drying, the mean weight of debris was assessed with a microbalance and statistically analyzed using analysis of variance and the post hoc Student-Newman-Keuls test. The time required to prepare the canals with the different instruments was also recorded.Results: The reciprocating files produced significantly more debris compared with both rotary systems (P < .05). Although no statistically significant difference was obtained between the 2 rotary instruments (P > .05), the reciprocating single-file system Reciproc produced significantly more debris compared with all other instruments (P < .05). Instrumentation was significantly faster using Reciproc than with all other instrument (P < .05).Conclusions: Under the condition of this study, all systems caused apical debris extrusion. Full-sequence rotary instrumentation was associated with less debris extrusion compared with the use of reciprocating single-file systems.

Effect of Disinfection Solutions on the Adhesion Force of Root Canal Filling Materials

Danielle Ferreira de Assis, Maíra do Prado, Renata A. Simão — 2012-02-06

Abstract: Introduction: Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) are usually used to disinfect gutta-percha (GP) and Resilon (Res) cones. This study investigated the adhesion force (Fad) between root canal sealers and GP and Res cones following different disinfection protocols by using atomic force microscopy.Methods: Nine flat surfaces of each material were obtained with medium points of GP and Res. The samples were divided into 6 groups (n = 3): control group GP, immersion in distilled water (DW); NaOCl group GP, immersion in 5.25% NaOCl and then washing with DW; CHX group GP, immersion in 2% CHX and then washing with DW; control group Res, immersion in DW; NaOCl group Res, immersion in 5.25% NaOCl and then washing with DW; and CHX group Res, immersion in 2% CHX and then washing with DW. Atomic force microscopy tips containing AH Plus sealer were used to obtain force versus distance curves regarding GP surfaces. Fad was calculated from the force curves. The same procedure was performed with Real Seal SE and Res surfaces. Data were statistically analyzed.Results: A higher Fad between solid filling materials (GP and Res) and root canal sealers was found when CHX solution was used. Treatment with NaOCl solution did not show influence on the Fad values.Conclusions: The decontamination of GP and Res with 2% CHX resulted in higher Fad values. The use of CHX in the disinfection process of GP and Res cones might be a better option before root canal obturation.

Use of Large-volume Cone-Beam Computed Tomography in Identification and Localization of Horizontal Root Fracture in the Presence and Absence of Intracanal Metallic Post

2012-04-30

Abstract: Introduction: The objective of the study was to evaluate the ability of large-volume cone-beam computed tomography (CBCT) to detect horizontal root fracture and to test the influence of a metallic post.Methods: Through the examination of 40 teeth by large-volume CBCT (20-cm height and 15-cm diameter cylinder) at 0.2-mm voxel resolution, 2 observers analyzed the samples for the presence and localization of horizontal root fracture.Results: The values of accuracy in the groups that had no metallic post ranged from 33%–68%, whereas for the samples with the metallic post, values showed a wide variation (38%–83%). Intraobserver agreement showed no statistically significant difference between the groups with/without metallic post; both ranged from very weak to weak (kappa, 0.09–0.369).Conclusions: The low accuracy and low intraobserver and interobserver agreement reflect the difficulty in performing an adequate diagnosis of horizontal root fractures through a large-volume CBCT by using a small voxel reconstruction.

Effect of Different Final Irrigation Solutions on Dentinal Tubule Penetration Depth and Percentage of Root Canal Sealer

Aysun Kara Tuncer, Safa Tuncer — 2012-04-27

Abstract: Introduction: The purpose of this study was to evaluate the effects of different solutions used for final irrigation on sealer penetration into dentinal tubules.Methods: Thirty-two recently extracted human mandibular premolar teeth were treated with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 4 groups according to the final irrigation solution used: (1) the EDTA group: 17% EDTA + 2.5% NaOCl, (2) the maleic acid (MA) group: 7% MA + 2.5% NaOCl, (3) the citric acid (CA) group: 10% CA + 2.5% NaOCl, and (4) the control group: 2.5% NaOCl. All teeth were obturated using the cold lateral condensation technique with gutta-percha and AH 26 sealer (Dentsply; DeTrey, Konstanz, Germany) labeled with fluorescent dye. The teeth were sectioned at distances of 2, 5, and 8 mm from the root apex. Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy.Results: The Kruskal-Wallis analysis results showed that there was a significant difference in the percentage and maximum depth of sealer penetration among all groups in all sections (P < .05).The coronal sections in each group showed a significantly higher percentage and maximum depth of sealer penetration than did the apical and middle sections (P < .05).Conclusions: Final irrigation with EDTA, MA, and CA after the use of NaOCl affected sealer penetration. However, there was no significant difference between these experimental groups (EDTA, MA, and CA) in all sections.

A Clinical and Histological Report of a Tooth with an Open Apex Treated with Regenerative Endodontics Using Platelet-rich Plasma

Mahmoud Torabinejad, Hadi Faras — 2012-06-01

Abstract: Introduction: In patients, the outcomes of teeth with necrotic pulps and open apexes that have been treated with regenerative endodontics have always been evaluated clinically and radiographically. The purpose of this case report is to present the clinical, radiographic, and histological findings of a regenerative procedure using platelet-rich plasma (PRP) 14 months after the procedure.Methods: A 12-year-old boy whose maxillary second premolar tooth had been treated with regenerative endodontics was seen with a chief complaint of pain and sensitivity to cold. After clinical and radiographic examinations, a pulpal diagnosis of reversible pulpitis and normal periapical tissues was made for this tooth. Because of the patient’s complaint and his guardian’s insistence on either a root canal treatment or an extraction, a root canal treatment was performed in this tooth. After entry into the root canal, the soft tissue present in the canal was removed with the aid of a large barbed broach and examined histologically.Results: Examination of the tissue removed from the root canal of this tooth revealed the presence of a vital pulp-like vital connective tissue. There was no evidence of bone in the specimen. Very few inflammatory cells were noted in the periphery of the specimen.Conclusions: Based on these findings, it appears that pulp-like tissue can be generated in a human tooth with the use of PRP as a scaffold in regenerative endodontic procedures.

Retraction Notice to Mineralized Tissue Formation by Bone Morphogenetic Protein-7–transfected Pulp Stem Cells: J Endod 38(2012)170–176

Xuechao Yang, Siyuan Zhang, Xin Pang, Mingwen Fan — 2012-06-01

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). Reason: The Editorial Board of the Journal of Endodontics has received an allegation of data fabrication of an article published in the February issue of the Journal (Yang et al., JOE 38:170–76, 2012). After review of available evidence, the Editorial Board believes there is sufficient evidence to doubt the veracity of the publication. Accordingly, we have retracted publication of this article.

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2012-06-01

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2012-06-01

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2012-06-01

Journal of Endodontics

Frequency and Distribution of Radiolucent Jaw Lesions: A Retrospective Analysis of 9,723 Cases

Effect of Platelet Concentrate on Quality of Life after Periradicular Surgery: A Randomized Clinical Study

Correlation between Clinical/Radiographic Features and Inflammatory Cytokine Networks Produced by Macrophages Stimulated with Endodontic Content

Differential Expression of MicroRNAs in Normal and Inflamed Human Pulps

Comparative Evaluation of 1.8 mL and 3.6 mL of 2% Lidocaine with 1:200,000 Epinephrine for Inferior Alveolar Nerve Block in Patients with Irreversible Pulpitis: A Prospective, Randomized Single-blind Study

Simvastatin Alleviates the Progression of Periapical Lesions by Modulating Autophagy and Apoptosis in Osteoblasts

The Levels of Vascular Endothelial Growth Factor and Bone Morphogenetic Protein 2 in Dental Pulp Tissue of Healthy and Diabetic Patients

Lysyl Oxidase and the Lysyl Oxidase–like Protein Modulate Odontoblastic Differentiation of Human Dental Pulp Cells

Regulation of Vascular Cell Adhesion Molecule-1 in Dental Pulp Cells by Interleukin-1β: The Role of Prostanoids

Cytidine-Phosphate-Guanosine Oligonucleotides Induce Interleukin-8 Production through Activation of TLR9, MyD88, NF-κB, and ERK Pathways in Odontoblast Cells

Anandamide Induces Matrix Metalloproteinase-2 Production through Cannabinoid-1 Receptor and Transient Receptor Potential Vanilloid-1 in Human Dental Pulp Cells in Culture

Isolation and Identification of CXCR4-positive Cells from Human Dental Pulp Cells

Changes in Proliferation and Osteogenic Differentiation of Stem Cells from Deep Caries In Vitro

Toll-like Receptor 2 Knockout Mice Showed Increased Periapical Lesion Size and Osteoclast Number

Quantitative Determination of High-temperature Requirement Protein A1 and Its Possible Associated Molecules during Induced Reparative Dentin Formation

Decreased Bacterial Adherence and Biofilm Growth on Surfaces Coated with a Solution of Benzalkonium Chloride

Residual Activity of Chelating Agents and their Combinations with Cetrimide on Root Canals Infected with Enterococcus faecalis

Effects of Calcium Silicate–based Materials on Collagen Matrix Integrity of Mineralized Dentin

Effect of Ultrasonic Activation on pH and Calcium Released by Calcium Hydroxide Pastes in Simulated External Root Resorption

Comparison of the Cleaning Efficacy of Different Final Irrigation Techniques

Evaluation of Radiopacity, pH, Release of Calcium Ions, and Flow of a Bioceramic Root Canal Sealer

Self-Adjusting File Cleaning-Shaping-Irrigation System Optimizes the Filling of Oval-shaped Canals with Thermoplasticized Gutta-percha

Apically Extruded Debris with Reciprocating Single-File and Full-sequence Rotary Instrumentation Systems

Effect of Disinfection Solutions on the Adhesion Force of Root Canal Filling Materials

Use of Large-volume Cone-Beam Computed Tomography in Identification and Localization of Horizontal Root Fracture in the Presence and Absence of Intracanal Metallic Post

Effect of Different Final Irrigation Solutions on Dentinal Tubule Penetration Depth and Percentage of Root Canal Sealer

A Clinical and Histological Report of a Tooth with an Open Apex Treated with Regenerative Endodontics Using Platelet-rich Plasma

Retraction Notice to Mineralized Tissue Formation by Bone Morphogenetic Protein-7–transfected Pulp Stem Cells: J Endod 38(2012)170–176

In Appreciation of Annual Session Sponsors

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News

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