101
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Tjäderhane L, Carrilho MR, Breschi L, Tay FR, Pashley DH. Dentin basic structure and composition-an overview. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1601-1546.2012.00269.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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102
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Chung MK, Jue SS, Dong X. Projection of non-peptidergic afferents to mouse tooth pulp. J Dent Res 2012; 91:777-82. [PMID: 22668597 DOI: 10.1177/0022034512450298] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A large proportion of pulpal nociceptors are known to contain neuropeptides such as CGRP. However, the projection of non-peptidergic nociceptors to tooth pulp is controversial. Recently, the non- peptidergic subset of nociceptors has been implicated in mechanical pain in the skin. Since mechanical irritation of pulpal nociceptors is critical for evoking tooth pain under pathophysiological conditions, we investigated whether the non-peptidergic afferents project to tooth pulp as potential mechanotransducing afferents. For clear visualization of the non-peptidergic afferents, we took advantage of a recently generated knock-in mouse model in which an axonal tracer, farnesylated green fluorescence protein (GFP), is expressed from the locus of a sensory neuron-specific gene, Mrgprd. In the trigeminal ganglia (TG), we demonstrated that GFP is exclusively expressed in afferents binding to isolectin B4 (IB4), a neurochemical marker of non-peptidergic nociceptors, but is rarely co-localized with CGRP. Retrograde labeling of pulpal afferents demonstrated that a low proportion of pulpal afferents was co-localized with GFP. Immunohistochemical detection of the axonal tracer revealed that GFP-positive afferent terminals were densely projected into the tooth pulp. These results provide convincing evidence that non-peptidergic nociceptors are projected into the tooth pulp and suggest a potential role for these afferents in tooth pain.
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Affiliation(s)
- M-K Chung
- Department of Neural and Pain Sciences, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA.
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103
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Setzer FC, Kataoka SHH, Natrielli F, Gondim-Junior E, Caldeira CL. Clinical diagnosis of pulp inflammation based on pulp oxygenation rates measured by pulse oximetry. J Endod 2012; 38:880-3. [PMID: 22703647 DOI: 10.1016/j.joen.2012.03.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 03/27/2012] [Accepted: 03/27/2012] [Indexed: 10/28/2022]
Abstract
INTRODUCTION The objective of this study was to investigate correlations between pulp oxygenation rates (%SpO(2)) and clinical diagnoses of reversible pulpitis (RP), irreversible pulpitis (IP), or pulp necrosis (PN). METHODS Sixty patients who presented with a tooth with endodontic pathology were grouped according to a clinical diagnosis of either RP (n = 20), IP (n = 20), or PN (n = 20). The clinical diagnosis was based on the patient's dental history, periapical radiographs, clinical inspection, and percussion and thermal sensitivity testing. Pulse oximetry (PO) was used to determine pulp oxygenation rates. For every patient, one additional endodontically treated tooth (negative control [NC], n = 60) and one additional healthy tooth with healthy pulp status (positive control [PC], n = 60) were evaluated. Analysis of variance, the Tukey HSD test, and the Student's t test were used for statistical analysis. RESULTS The mean %SpO(2) levels were as follows: RP: 87.4% (standard deviation [SD] ±2.46), IP: 83.1% (SD ±2.29), PN: 74.6% (SD ±1.96), PC: 92.2% (SD ±1.84), and NC: 0% (SD ±0.0). There were statistically significant differences between RP, IP, and PN compared with NC and PC and between RP, IP, and PN (all P ≤ .01). CONCLUSIONS The evaluation of pulp oxygenation rates by PO may be a useful tool to determine the different inflammatory stages of the pulp to aid in endodontic diagnosis.
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Affiliation(s)
- Frank C Setzer
- Department of Endodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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104
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Moe K, Shrestha A, Kvinnsland IH, Luukko K, Kettunen P. Developmentally regulated expression of Sema3A chemorepellant in the developing mouse incisor. Acta Odontol Scand 2012; 70:184-9. [PMID: 21793640 DOI: 10.3109/00016357.2011.600717] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Semaphorin 3A (Sema3A) is an essential chemorepellant controlling peripheral axon pathfinding and patterning, but also serves non-neuronal cellular functions. Incisors of rodent are distinctive from molars as they erupt continuously, have only one root and enamel is present only on the labial side. The aim of this study is to address putative regulatory roles of Sema3A chemorepellant in the development of incisor innervation and formation. MATERIALS AND METHODS This study analyzed expression of Sema3A mRNAs during embryonic and early post-natal stages of mouse mandibular incisor using sectional radioactive in situ hybridization. RESULTS Although Sema3A mRNAs were observed in condensed dental mesenchyme during the early bud stage, they were absent in dental papilla or pulp at later stages. Sema3A mRNAs were observed in the dental epithelium including the cervical loops and a prominent expression was also seen in alveolar bone. Interestingly, transcripts were absent from the mesenchymal dental follicle target area (future periodontal ligament) throughout the studied stages. CONCLUSION The expression patterns of Sema3A indicate that it may control the timing and patterning of the incisor innervation. In particular, Sema3A appears to regulate innervation of the periodontal ligament, while nerve penetration into the incisor dental pulp appears not to be dependent on Sema3A. Moreover, Sema3A may regulate the functions of cervical loops and the development of alveolar bone. Future study with Sema3A deficient mice will help to elucidate the putative neuronal and non-neuronal functions of Sema3A in incisor tooth development.
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Affiliation(s)
- Kyaw Moe
- Department of Biomedicine, University of Bergen, Norway
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105
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Mitrirattanakul S, Poomsawat S, Fuangtharnthip P. Cannabinoid receptor 1 (CB1R) expression in rat dental pulp. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/s1348-8643(12)00003-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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106
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Unmyelinated nerve fibers in the human dental pulp express markers for myelinated fibers and show sodium channel accumulations. BMC Neurosci 2012; 13:29. [PMID: 22429267 PMCID: PMC3323891 DOI: 10.1186/1471-2202-13-29] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 03/19/2012] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The dental pulp is a common source of pain and is used to study peripheral inflammatory pain mechanisms. Results show most fibers are unmyelinated, yet recent findings in experimental animals suggest many pulpal afferents originate from fibers that are myelinated at more proximal locations. Here we use the human dental pulp and confocal microscopy to examine the staining relationships of neurofilament heavy (NFH), a protein commonly expressed in myelinated afferents, with other markers to test the possibility that unmyelinated pulpal afferents originate from myelinated axons. Other staining relationships studied included myelin basic protein (MBP), protein gene product (PGP) 9.5 to identify all nerve fibers, tyrosine hydroxylase (TH) to identify sympathetic fibers, contactin-associated protein (caspr) to identify nodal sites, S-100 to identify Schwann cells and sodium channels (NaChs). RESULTS Results show NFH expression in most PGP9.5 fibers except those with TH and include the broad expression of NFH in axons lacking MBP. Fibers with NFH and MBP show NaCh clusters at nodal sites as expected, but surprisingly, NaCh accumulations are also seen in unmyelinated fibers with NFH, and in fibers with NFH that lack Schwann cell associations. CONCLUSIONS The expression of NFH in most axons suggests a myelinated origin for many pulpal afferents, while the presence of NaCh clusters in unmyelinated fibers suggests an inherent capacity for the unmyelinated segments of myelinated fibers to form NaCh accumulations. These findings have broad implications on the use of dental pulp to study pain mechanisms and suggest possible novel mechanisms responsible for NaCh cluster formation and neuronal excitability.
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107
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ZHU YJ, XU F, SU JH, ZHOU H, LU TJ. MATHEMATICAL MODELING FOR THE PREDICTION AND IMPROVEMENT OF TOOTH THERMAL PAIN: A REVIEW. J MECH MED BIOL 2012. [DOI: 10.1142/s0219519411004095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Tooth pain, especially tooth thermal pain, is one of the most important symptoms and signs in dental clinic and daily life. As a special sensation, pain has been studied extensively in both clinic and experimental research aimed at reducing or eliminating the possible negative effects of pain. Unfortunately, the full underlying mechanism of pain is still unclear, because the pain could be influenced by many factors, including physiological, psychological, physical, chemical, and biological factors and so on. Besides, most studies on pain mechanisms in the literature are based on skin pain sensation and only few are based on tooth pain. In this paper, we present a comprehensive review on both neurophysiology of tooth pain mechanism, and corresponding thermal, mechanical, and thermomechanical behaviors of teeth. We also describe a multiscale modeling approach for quantifying tooth thermal pain by integrating the mathematic methods of engineering into the neuroscience. The mathematical model of tooth thermal pain will enable better understanding of thermal pain mechanism and optimization of existing diagnosis and treatment in dental clinic.
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Affiliation(s)
- Y. J. ZHU
- Stomatological Hospital, College of Medicine, Biomedical Engineering and Biomechanics Center, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - F. XU
- Biomedical Engineering and Biomechanics Center, Xi'an Jiaotong University, Xi'an 710049, P. R. China
- School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - J. H. SU
- Biomedical Engineering and Biomechanics Center, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - H. ZHOU
- Stomatological Hospital, College of Medicine, Xi'an Jiaotong University, Xi'an 710004, P. R. China
| | - T. J. LU
- Biomedical Engineering and Biomechanics Center, Xi'an Jiaotong University, Xi'an 710049, P. R. China
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108
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LIN M, LUO ZY, BAI BF, XU F, LU TJ. FLUID DYNAMICS ANALYSIS OF SHEAR STRESS ON NERVE ENDINGS IN DENTINAL MICROTUBULE: A QUANTITATIVE INTERPRETATION OF HYDRODYNAMIC THEORY FOR DENTAL PAIN. J MECH MED BIOL 2011. [DOI: 10.1142/s0219519411003983] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Noxious thermal and/or mechanical stimuli applied to dentine can cause fluid flow in dentinal microtubules (DMTs). The fluid flow induces shear stress (SS) on intradental nerve endings and may excite pulpal mechanoreceptors to generate dental pain sensation. There exist numerous studies on dental thermal pain, but few are mathematical. For this, we developed a computational fluid dynamics (CFD) model of dentinal fluid flow (DFF) in innervated DMTs. Based on this model, we systematically investigated the effects of various parameters (e.g., biological structure, DFF velocity, and fluid properties) on the SS experienced by intradental nerve endings and thus provide a quantitative interpretation to the hydrodynamic theory. The dimensions of biological structures, odontoblastic process (OP) movement, dentinal fluid velocity, and viscosity were found to have significant influences on the SS while dentinal fluid density showed negligible influence under conditions studied. The results indicate that: (i) dental pain study of animal models may not be directly applied to human being and the results may even vary from one person to another and (ii) OP movement caused by DFF changes the dimension of the space for the fluid flow, affecting thus the SS on nerve endings. The present work enables better understanding of the mechanisms underlying dental pain sensation and quantification of dental pain intensity resulted from clinical procedures such as dentine sensitivity testing and dental restorative processes.
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Affiliation(s)
- M. LIN
- Biomedical Engineering and Biomechanics Center, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Z. Y. LUO
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University Xi'an 710049, P. R. China
| | - B. F. BAI
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University Xi'an 710049, P. R. China
| | - F. XU
- Biomedical Engineering and Biomechanics Center, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, P. R. China
- HST-Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - T. J. LU
- Biomedical Engineering and Biomechanics Center, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, P. R. China
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109
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Fried K, Sessle BJ, Devor M. The paradox of pain from tooth pulp: low-threshold "algoneurons"? Pain 2011; 152:2685-2689. [PMID: 21889261 DOI: 10.1016/j.pain.2011.08.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 07/24/2011] [Accepted: 08/02/2011] [Indexed: 11/29/2022]
Affiliation(s)
- Kaj Fried
- Department of Dental Medicine, Karolinska Institutet, S-141 04 Huddinge, Sweden Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6 Department of Cell and Developmental Biology, Institute of Life Sciences and Center for Research on Pain, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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110
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Nishikawa S. Fluorescent AM1-43 and FM1-43 probes for dental sensory nerves and cells: Their labeling mechanisms and applications. JAPANESE DENTAL SCIENCE REVIEW 2011. [DOI: 10.1016/j.jdsr.2010.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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111
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Oshima M, Mizuno M, Imamura A, Ogawa M, Yasukawa M, Yamazaki H, Morita R, Ikeda E, Nakao K, Takano-Yamamoto T, Kasugai S, Saito M, Tsuji T. Functional tooth regeneration using a bioengineered tooth unit as a mature organ replacement regenerative therapy. PLoS One 2011; 6:e21531. [PMID: 21765896 PMCID: PMC3134195 DOI: 10.1371/journal.pone.0021531] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 05/30/2011] [Indexed: 11/18/2022] Open
Abstract
Donor organ transplantation is currently an essential therapeutic approach to the replacement of a dysfunctional organ as a result of disease, injury or aging in vivo. Recent progress in the area of regenerative therapy has the potential to lead to bioengineered mature organ replacement in the future. In this proof of concept study, we here report a further development in this regard in which a bioengineered tooth unit comprising mature tooth, periodontal ligament and alveolar bone, was successfully transplanted into a properly-sized bony hole in the alveolar bone through bone integration by recipient bone remodeling in a murine transplantation model system. The bioengineered tooth unit restored enough the alveolar bone in a vertical direction into an extensive bone defect of murine lower jaw. Engrafted bioengineered tooth displayed physiological tooth functions such as mastication, periodontal ligament function for bone remodeling and responsiveness to noxious stimulations. This study thus represents a substantial advance and demonstrates the real potential for bioengineered mature organ replacement as a next generation regenerative therapy.
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Affiliation(s)
- Masamitsu Oshima
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Mitsumasa Mizuno
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, Japan
| | - Aya Imamura
- Department of Biological Science and Technology, Graduate School of Industrial Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Miho Ogawa
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- Organ Technologies Inc., Tokyo, Japan
| | - Masato Yasukawa
- Department of Biological Science and Technology, Graduate School of Industrial Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Hiromichi Yamazaki
- Department of Biological Science and Technology, Graduate School of Industrial Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Ritsuko Morita
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Etsuko Ikeda
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, Japan
| | - Kazuhisa Nakao
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Teruko Takano-Yamamoto
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai, Miyagi, Japan
| | - Shohei Kasugai
- Oral Implantology and Regenerative Dental Medicine Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Masahiro Saito
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- Department of Biological Science and Technology, Graduate School of Industrial Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
| | - Takashi Tsuji
- Research Institute for Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- Department of Biological Science and Technology, Graduate School of Industrial Science and Technology, Tokyo University of Science, Noda, Chiba, Japan
- Organ Technologies Inc., Tokyo, Japan
- * E-mail:
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112
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Chung MK, Lee J, Duraes G, Ro JY. Lipopolysaccharide-induced pulpitis up-regulates TRPV1 in trigeminal ganglia. J Dent Res 2011; 90:1103-7. [PMID: 21712529 DOI: 10.1177/0022034511413284] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Tooth pain often accompanies pulpitis. Accumulation of lipopolysaccharides (LPS), a product of Gram-negative bacteria, is associated with painful clinical symptoms. However, the mechanisms underlying LPS-induced tooth pain are not clearly understood. TRPV1 is a capsaicin- and heat-gated nociceptive ion channel implicated in thermosensation and hyperalgesia under inflammation or injury. Although TRPV1 is expressed in pulpal afferents, it is not known whether the application of LPS to teeth modulates TRPV1 in trigeminal nociceptors. By assessing the levels of protein and transcript of TRPV1 in mouse trigeminal ganglia, we demonstrate that dentinal application of LPS increases the expression of TRPV1. Our results suggest that the up-regulation of TRPV1 in trigeminal nociceptors following bacterial infection could contribute to hyperalgesia under pulpitis conditions.
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Affiliation(s)
- M-K Chung
- University of Maryland Baltimore School of Dentistry, Program in Neuroscience, Department of Neural and Pain Sciences, 650 W. Baltimore Street, Baltimore, MD 21201, USA.
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113
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Tsuboi Y, Iwata K, Dostrovsky JO, Chiang CY, Sessle BJ, Hu JW. Modulation of astroglial glutamine synthetase activity affects nociceptive behaviour and central sensitization of medullary dorsal horn nociceptive neurons in a rat model of chronic pulpitis. Eur J Neurosci 2011; 34:292-302. [PMID: 21707791 DOI: 10.1111/j.1460-9568.2011.07747.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Previous studies indicate that the astroglial glutamate-glutamine shuttle may be involved in acute pulpal inflammatory pain by influencing central sensitization induced in nociceptive neurons in the trigeminal subnucleus caudalis [the medullary dorsal horn (MDH)] by application of an inflammatory irritant to the rat tooth pulp. The aim of this study was to test if intrathecal application to the rat medulla of the astroglial glutamine synthetase inhibitor methionine sulfoximine (MSO) can influence the central sensitization of MDH nociceptive neurons and the animal's associated behaviour that are manifested in a model of chronic pulpitis pain induced by exposure of a mandibular molar pulp. This model was found to be associated with nocifensive behaviour and enhanced reflex activity evoked by mechanical stimulation of the rat's facial skin and with immunocytochemical evidence of astroglial activation in the MDH. These features were apparent for up to 28 days post-operatively. During this post-operative period, the nocifensive behaviour and enhanced reflex activity were significantly attenuated by intrathecal application of MSO (5 μL, 10 mM) but not by vehicle application. In electrophysiological recordings of nociceptive neuronal activity in the MDH, central sensitization was also evident in pulp-exposed rats but not in intact rats and could be significantly attenuated by MSO application but not by vehicle application. These behavioural and neuronal findings suggest that the astroglial glutamate-glutamine shuttle is responsible for the maintenance of inflammation-induced nocifensive behavioural changes and the accompanying central sensitization in MDH nociceptive neurons in this chronic pulpitis pain model.
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Affiliation(s)
- Y Tsuboi
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
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114
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Canzobre MC, Ríos H. Nicotinamide adenine dinucleotide phosphate/neuronal nitric oxide synthase-positive neurons in the trigeminal subnucleus caudalis involved in tooth pulp nociception. J Neurosci Res 2011; 89:1478-88. [PMID: 21608012 DOI: 10.1002/jnr.22676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/22/2011] [Accepted: 03/29/2011] [Indexed: 12/19/2022]
Abstract
Sensory information on facial structures, including teeth pulp, periodontium, and gingiva, is relayed in the trigeminal complex. Tooth pulp inflammation constitutes a common clinical problem, and this peripheral injury can induce neuroplastic changes in trigeminal nociceptive neurons. There is considerable evidence that the trigeminal subnucleus caudalis (Vc) is the principal relay for trigeminal nociceptive information as well as modulation of the painful stimuli. Glutamatergic primary afferents innervating the tooth pulp project to the most superficial laminae of the Vc. N-methyl-D-aspartate receptor stimulation leads to the activation of the enzyme nitric oxide synthase (NOS), which synthesizes the free radical nitric oxide (NO). This enzyme is expressed mainly in lamina II interneurons, and in a small number of cells in lamina I as well as in deep laminae projection neurons of Vc. In the present study, we analyzed the temporal changes in neuronal NOS (nNOS) in Vc local circuitries after unilateral intermediate molar pulp injury. Our results demonstrate that a peripheral dental pulp injury leads to neuroplastic changes in the relative amount and activity of nNOS enzyme. Moreover, after a period of time, the nitrergic system shifts to the initial values, independently of the persistence of inflammation in the pulp tissues.
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Affiliation(s)
- Mariela C Canzobre
- Instituto de Biología Celular y Neurociencias Prof. E. De Robertis, Facultad de Medicina, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
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115
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Fluid mechanics in dentinal microtubules provides mechanistic insights into the difference between hot and cold dental pain. PLoS One 2011; 6:e18068. [PMID: 21448459 PMCID: PMC3063177 DOI: 10.1371/journal.pone.0018068] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 02/19/2011] [Indexed: 11/19/2022] Open
Abstract
Dental thermal pain is a significant health problem in daily life and dentistry. There is a long-standing question regarding the phenomenon that cold stimulation evokes sharper and more shooting pain sensations than hot stimulation. This phenomenon, however, outlives the well-known hydrodynamic theory used to explain dental thermal pain mechanism. Here, we present a mathematical model based on the hypothesis that hot or cold stimulation-induced different directions of dentinal fluid flow and the corresponding odontoblast movements in dentinal microtubules contribute to different dental pain responses. We coupled a computational fluid dynamics model, describing the fluid mechanics in dentinal microtubules, with a modified Hodgkin-Huxley model, describing the discharge behavior of intradental neuron. The simulated results agreed well with existing experimental measurements. We thence demonstrated theoretically that intradental mechano-sensitive nociceptors are not “equally sensitive” to inward (into the pulp) and outward (away from the pulp) fluid flows, providing mechanistic insights into the difference between hot and cold dental pain. The model developed here could enable better diagnosis in endodontics which requires an understanding of pulpal histology, neurology and physiology, as well as their dynamic response to the thermal stimulation used in dental practices.
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116
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Affiliation(s)
- Kenneth M Hargreaves
- Departments of Endodontics, Pharmacology, Physiology and Surgery, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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117
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Sessle BJ. Peripheral and central mechanisms of orofacial inflammatory pain. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 97:179-206. [DOI: 10.1016/b978-0-12-385198-7.00007-2] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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118
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Fan W, Huang F, Zhu X, Dong W, Gao Z, Li D, He H. Involvement of microglial activation in the brainstem in experimental dental injury and inflammation. Arch Oral Biol 2010; 55:706-11. [DOI: 10.1016/j.archoralbio.2010.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 06/02/2010] [Accepted: 06/14/2010] [Indexed: 12/18/2022]
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119
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Beneng K, Renton T, Yilmaz Z, Yiangou Y, Anand P. Cannabinoid receptor CB1-immunoreactive nerve fibres in painful and non-painful human tooth pulp. J Clin Neurosci 2010; 17:1476-9. [PMID: 20705472 DOI: 10.1016/j.jocn.2010.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 04/08/2010] [Indexed: 11/18/2022]
Abstract
The cannabinoid receptor CB1 is involved in modulation of neuronal hypersensitivity and pain. The aim of this study was to evaluate CB1 receptor levels for the first time in dental pain. A total of 19 patients due for molar extraction were divided into two groups, those with existing dental pain (n=9), and those with no history of pain (n=10). Immunohistochemistry and computer image analysis was used to evaluate CB1-positive nerve fibres in tooth pulp, with neurofilament-immunostaining as a structural nerve marker. CB1-immunoreactive nerve fibres were scattered throughout the tooth pulp and often seen in nerve bundles, but the fibres did not penetrate the subodontoblastic layer. There was no statistically significant change in the CB1 nerve fibre percentage area in the painful group compared to the non-painful group (p=0.146); the neurofilament fibres were significantly reduced in the painful group compared to the controls (p=0.028), but there was no difference in the ratio of CB1 to neurofilaments between the two groups. Thus, CB1 expression is maintained by nerve fibres in painful human dental pulp, and peripherally-restricted CB1 agonists currently in development may advance the treatment of dental pain.
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Affiliation(s)
- K Beneng
- Dental Institute, King's College London, Guy's Hospital, Oral Surgery Department, Great Maze Pond, London, UK
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Komabayashi T, Zhu Q. Innovative endodontic therapy for anti-inflammatory direct pulp capping of permanent teeth with a mature apex. ACTA ACUST UNITED AC 2010; 109:e75-81. [PMID: 20416524 DOI: 10.1016/j.tripleo.2009.12.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Accepted: 12/23/2009] [Indexed: 10/19/2022]
Abstract
Direct pulp capping is treatment of an exposed vital pulp with a dental material to facilitate the formation of reparative dentin and maintenance of vital pulp. It has been studied as an alternate way to avoid vital pulp extirpation. However, the success rate of pulp capping is much lower than that of vital pulp extirpation. Therefore, direct pulp capping is currently considered controversial by many clinicians. To increase the success rate, a critical need exists to develop new biologically based therapeutics that reduce pulp inflammation, promote the continued formation of new dentin-pulp complex, and restore vitality by stimulating the regrowth of pulpal tissue. Bioengineered anti-inflammatory direct pulp-capping materials, together with adhesive materials for leakage prevention, have great potential to improve the condition of the existing pulp from an inflamed to a noninflamed status and lead to a high rate of long-term success.
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Affiliation(s)
- Takashi Komabayashi
- Department of Endodontics, Texas A&M Health Science Center, Baylor College of Dentistry, Dallas, TX, USA.
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121
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Kivell B, Prisinzano TE. Kappa opioids and the modulation of pain. Psychopharmacology (Berl) 2010; 210:109-19. [PMID: 20372880 DOI: 10.1007/s00213-010-1819-6] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 02/24/2010] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND RATIONALE Pain is a complex sensory experience, involving cognitive factors, environment (setting, society, and culture), experience, and gender and is modulated significantly by the central nervous system (CNS). The mechanisms by which opioid analgesics work are understood, but this class of drugs is not ideal as either an analgesic or anti-hyperalgesic. Accordingly, considerable effort continues to be directed at improved understanding of nociceptor function and development of selective analgesics that do not have the unwanted effects associated with opioid analgesics. OBJECTIVE The purpose of this paper is to provide a review of the role of KOP receptors in the modulation of pain and highlight several chemotypes currently being explored as peripherally restricted KOP ligands. RESULTS A growing body of literature has shown that KOP receptors are implicated in a variety of behavioral pain models. Several different classes of peripherally restricted peptidic and nonpeptidic KOP agonists have been identified and show utility in treating painful conditions. CONCLUSION The pharmacological profile of KOP agonists in visceral pain models suggest that peripherally restricted KOP agonists are potentially useful for a variety of peripheral pain states. Further, clinical investigation of peripherally restricted KOP agonists will help to clarify the painful conditions where KOP agonists will be most effective.
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MESH Headings
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/therapeutic use
- Animals
- Disease Models, Animal
- Humans
- Mechanoreceptors/physiology
- Nociceptors/physiology
- Pain/drug therapy
- Pain/metabolism
- Pain/physiopathology
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/antagonists & inhibitors
- Receptors, Opioid, kappa/physiology
- Receptors, Opioid, mu/agonists
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Affiliation(s)
- Bronwyn Kivell
- School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
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122
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Weigelt A, Terekhin P, Kemppainen P, Dörfler A, Forster C. The representation of experimental tooth pain from upper and lower jaws in the human trigeminal pathway. Pain 2010; 149:529-538. [DOI: 10.1016/j.pain.2010.03.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 03/04/2010] [Accepted: 03/19/2010] [Indexed: 11/15/2022]
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123
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Li YQ, Li H, Wei J, Qu L, Wu LA. Expression changes of K+-Cl- co-transporter 2 and Na+-K+-Cl- co-transporter1 in mouse trigeminal subnucleus caudalis following pulpal inflammation. Brain Res Bull 2010; 81:561-4. [PMID: 20067823 DOI: 10.1016/j.brainresbull.2010.01.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 12/23/2009] [Accepted: 01/06/2010] [Indexed: 10/20/2022]
Abstract
Cation chloride co-transporters, including K(+)-Cl(-) co-transporter 2 (KCC2) and Na(+)-K(+)-Cl(-) co-transporter 1 (NKCC1), are of particular importance to GABAergic transmission and thus involved in the development of hyperalgesia at the spinal level. However, it is largely unknown whether these co-transporters in the trigeminal system contribute to dental pain. In this study, we investigated the expression of KCC2 and NKCC1 mRNAs in mouse trigeminal subnucleus caudalis (Vc) after lipopolysaccharide (LPS) application to the tooth pulp by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) method. KCC2 mRNA was found to be down-regulated at 1d after pulpal inflammation, while NKCC1 was up-regulated. Blockade of endogenous brain-derived neurotrophic factor-tyrosine receptor kinase B pathway with K252a produced pronounced antinociception as evidenced by decreased tongue protrusion behavior in LPS-treated mice. These data suggest that KCC2 and NKCC1 in Vc may play a critical role in the nociception and transmission of dental pain during pulpal inflammation.
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Affiliation(s)
- Yong-Qi Li
- Comprehensive Diagnostic and Therapeutic Center, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
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124
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Nusstein JM, Reader A, Drum M. Local anesthesia strategies for the patient with a "hot" tooth. Dent Clin North Am 2010; 54:237-247. [PMID: 20433976 DOI: 10.1016/j.cden.2009.12.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Attaining local anesthesia for the treatment of teeth diagnosed with irreversible pulpitis ("hot" tooth) can be a challenge. This article looks at the strategies a dentist can use to help achieve adequate pulpal anesthesia for the patient, thereby eliminating or reducing treatment pain.
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Affiliation(s)
- John M Nusstein
- Division of Endodontics, The Ohio State University College of Dentistry, 305 West 12th Avenue, Room 3058, Columbus, OH 43210, USA.
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125
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Wu LA, Huang J, Wang W, Wang W, Li YQ, Wang XJ, Wu SX. Activation of GABAergic neurons following tooth pulp stimulation. J Dent Res 2010; 89:532-6. [PMID: 20332333 DOI: 10.1177/0022034510363231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The functional impact of GABA (gamma-aminobutyric acid)ergic neurons in nociceptive transmission of the spinal trigeminal nucleus is not fully established. Using both the glutamic acid decarboxylase (GAD)(67)-green fluorescence protein (GFP) knock-in mouse and the tooth pulp stimulation model, we performed double-immunofluorescent histochemistry to determine the characteristics of GABAergic neuron activation in the spinal trigeminal nucleus. The number of Fos-positive GABAergic neuronal profiles was significantly increased 2 hrs after tooth pulp stimulation. The Fos/GFP double-labeled neurons were mainly present in superficial laminae of the spinal trigeminal subnucleus interpolaris-caudalis transition (Vi/Vc) and subnucleus caudalis (Vc) on the side ipsilateral to the stimulation. Subsequently, the number of double-labeled neurons decreased gradually and became comparable with that of the controls by 48 hrs. Our results provide direct morphological evidence that a subset of GABAergic neurons in the spinal trigeminal system was activated during tooth pulp stimulation.
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Affiliation(s)
- L-A Wu
- Department of Paediatric Dentistry, School of Stomatology, Fourth Military Medical University, No. 145 West Changle Road, Xi'an 710032, China
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126
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Tarsa L, Bałkowiec-Iskra E, Kratochvil FJ, Jenkins VK, McLean A, Brown AL, Smith JA, Baumgartner JC, Balkowiec A. Tooth pulp inflammation increases brain-derived neurotrophic factor expression in rodent trigeminal ganglion neurons. Neuroscience 2010; 167:1205-15. [PMID: 20223282 DOI: 10.1016/j.neuroscience.2010.03.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Revised: 02/06/2010] [Accepted: 03/02/2010] [Indexed: 12/23/2022]
Abstract
Nociceptive pathways with first-order neurons located in the trigeminal ganglion (TG) provide sensory innervation to the head, and are responsible for a number of common chronic pain conditions, including migraines, temporomandibular disorders and trigeminal neuralgias. Many of those conditions are associated with inflammation. Yet, the mechanisms of chronic inflammatory pain remain poorly understood. Our previous studies show that the neurotrophin brain-derived neurotrophic factor (BDNF) is expressed by adult rat TG neurons, and released from cultured newborn rat TG neurons by electrical stimulation and calcitonin gene-related peptide (CGRP), a well-established mediator of trigeminal inflammatory pain. These data suggest that BDNF plays a role in activity-dependent plasticity at first-order trigeminal synapses, including functional changes that take place in trigeminal nociceptive pathways during chronic inflammation. The present study was designed to determine the effects of peripheral inflammation, using tooth pulp inflammation as a model, on regulation of BDNF expression in TG neurons of juvenile rats and mice. Cavities were prepared in right-side maxillary first and second molars of 4-week-old animals, and left open to oral microflora. BDNF expression in right TG was compared with contralateral TG of the same animal, and with right TG of sham-operated controls, 7 and 28 days after cavity preparation. Our ELISA data indicate that exposing the tooth pulp for 28 days, with confirmed inflammation, leads to a significant upregulation of BDNF in the TG ipsilateral to the affected teeth. Double-immunohistochemistry with antibodies against BDNF combined with one of nociceptor markers, CGRP or transient receptor potential vanilloid type 1 (TRPV1), revealed that BDNF is significantly upregulated in TRPV1-immunoreactive (IR) neurons in both rats and mice, and CGRP-IR neurons in mice, but not rats. Overall, the inflammation-induced upregulation of BDNF is stronger in mice compared to rats. Thus, mouse TG provides a suitable model to study molecular mechanisms of inflammation-dependent regulation of BDNF expression in vivo.
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Affiliation(s)
- L Tarsa
- Department of Integrative Biosciences, Oregon Health & Science University School of Dentistry, Portland, OR 97239, USA
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127
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Canzobre MC, Ríos H. Pulpar tooth injury induces plastic changes in S100B positive astroglial cells in the trigeminal subnucleus caudalis. Neurosci Lett 2010; 470:71-5. [DOI: 10.1016/j.neulet.2009.12.060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 12/14/2009] [Accepted: 12/22/2009] [Indexed: 12/22/2022]
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128
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Abstract
Pain is one of the most common reasons for which patients seek dental and medical care. Orofacial pain conditions consist of a wide range of disorders including odontalgia (toothache), temporomandibular disorders, trigeminal neuralgia and others. Most of these conditions are either inflammatory or neuropathic in nature. This chapter provides an overview of the commonly used models to study inflammatory and neuropathic orofacial pain.
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Affiliation(s)
- Asma Khan
- Department of Endodontics, University of North Carolina, Chapel Hill, NC, USA
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129
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Caviedes-Bucheli J, Rojas P, Escalona M, Estrada A, Sandoval C, Rivero C, Lombana N, Muñoz HR. The effect of different vasoconstrictors and local anesthetic solutions on substance P expression in human dental pulp. J Endod 2009; 35:631-3. [PMID: 19410073 DOI: 10.1016/j.joen.2008.12.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Revised: 12/17/2008] [Accepted: 12/24/2008] [Indexed: 10/20/2022]
Abstract
The purpose of this study was to quantify the effect of the infiltration injection of different vasoconstrictor and anesthetic solutions on substance P (SP) expression in healthy human dental pulp. Thirty pulp samples were obtained from healthy upper premolars in which extraction was indicated for orthodontic reasons and were randomly assigned into three groups of 10 samples each: 2% lidocaine with 1:80,000 epinephrine (Lido group), 3% Prilocaine with 1:200000 felypressin (Prilo group); and 4% Prilocaine without vasoconstrictor (Prilo-no-VC group). All teeth were extracted 10 minutes after anesthetic application. Pulp samples were processed and SP was measured by radioimmunoassay. SP expression for the Lido, Prilo, and Prilo-no-VC groups were 616.49, 663.76, and 760.79 pmol/mg pulp tissue, respectively. Analysis of variance showed statistically significant differences between groups (p = 0.001). Tukey Honestly Significant Difference (HSD) post hoc tests showed significant statistical differences between the Prilo-no-VC group and the Lido group (p < 0.01) and between the Prilo-no-VC group and the Prilo group (p < 0.05). It can be concluded that infiltration injection of local anesthetics with vasoconstrictor attenuate SP expression in human dental pulp.
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Affiliation(s)
- Javier Caviedes-Bucheli
- Department of Endodontics, School of Dentistry, Pontificia Universidad Javeriana, Bogotá, Colombia.
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130
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Fully functional bioengineered tooth replacement as an organ replacement therapy. Proc Natl Acad Sci U S A 2009; 106:13475-80. [PMID: 19666587 DOI: 10.1073/pnas.0902944106] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Current approaches to the development of regenerative therapies have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. The ultimate goal of regenerative therapy is to develop fully functioning bioengineered organs which work in cooperation with surrounding tissues to replace organs that were lost or damaged as a result of disease, injury, or aging. Here, we report a successful fully functioning tooth replacement in an adult mouse achieved through the transplantation of bioengineered tooth germ into the alveolar bone in the lost tooth region. We propose this technology as a model for future organ replacement therapies. The bioengineered tooth, which was erupted and occluded, had the correct tooth structure, hardness of mineralized tissues for mastication, and response to noxious stimulations such as mechanical stress and pain in cooperation with other oral and maxillofacial tissues. This study represents a substantial advance and emphasizes the potential for bioengineered organ replacement in future regenerative therapies.
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131
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Henry MA, Luo S, Foley BD, Rzasa RS, Johnson LR, Levinson SR. Sodium channel expression and localization at demyelinated sites in painful human dental pulp. THE JOURNAL OF PAIN 2009; 10:750-8. [PMID: 19559391 PMCID: PMC2750027 DOI: 10.1016/j.jpain.2009.01.264] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 12/09/2008] [Accepted: 01/12/2009] [Indexed: 11/18/2022]
Abstract
UNLABELLED The expression of sodium channels (NaCh(s)) change after inflammatory and nerve lesions, and this change has been implicated in the generation of pain states. Here we examine NaCh expression within nerve fibers from normal and painful extracted human teeth with special emphasis on their localization within large accumulations, like those seen at nodes of Ranvier. Pulpal tissue sections from normal wisdom teeth and from teeth with large carious lesions associated with severe and spontaneous pain were double-stained with pan-specific NaCh antibody and caspr (paranodal protein used to visualize nodes of Ranvier) antibody, while additional sections were triple-stained with NaCh, caspr and myelin basic protein (MBP) antibodies. Z-series of images were obtained with the confocal microscope and evaluated with NIH ImageJ software to quantify the density and size of NaCh accumulations, and to characterize NaCh localization at caspr-identified typical and atypical nodal sites. Although the results showed variability in the overall density and size of NaCh accumulations in painful samples, a common finding included the remodeling of NaChs at atypical nodal sites. This remodeling of NaChs included prominent NaCh expression within nerve regions that showed a selective loss of MBP staining in a pattern consistent with a demyelinating process. PERSPECTIVE This study identifies the remodeling of NaChs at demyelinated sites within the painful human dental pulp and suggests that the contribution of NaChs to spontaneous pulpal pain generation may be dependant not only on total NaCh density but may also be related to NaCh expression at atypical nodal sites.
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Affiliation(s)
- Michael A Henry
- Department of Endodontics, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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132
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Kido MA, Ibuki T, Danjo A, Kondo T, Zhang JQ, Yamaza T, Yamashita Y, Higuchi Y, Tanaka T. Immunocytochemical localization of the neurokinin 1 receptor in rat dental pulp. ACTA ACUST UNITED AC 2009; 68:259-65. [PMID: 16477146 DOI: 10.1679/aohc.68.259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The dentin-pulp complex is a peripheral end-organ supplied by dense sensory nerve fibers. Substance P, a representative neuropeptide widely distributed in the dental pulp, has been reported to play roles in pain transmission and the amplification of inflammation. We analyzed here the expression of the neurokinin 1 (NK1) receptor, preferentially activated by substance P, using immunocytochemistry in rat dental pulp at both the light and electron microscopic levels. Conspicuous NK1 receptor immunoreactivity was found in the odontoblasts; immunolabelings were present at their plasma membrane and endosomal structures, especially in their cytoplasmic processes. Immunoreactions for NK1 receptor were also detectable in a part of the nerve terminals associated with the cytoplasmic processes of the odontoblasts. Furthermore, the endothelial cells of capillaries and post-capillary venules and the fibroblasts were labeled with the NK1 receptor in the subodontoblast layer. These findings suggest that pulpal cells and nerve fibers are targets for substance P that mediate multiple functions, including a vasoactive function and the regulation of vascular permeability as well as the modulation of pain transmission.
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Affiliation(s)
- Mizuho A Kido
- Department of Oral Anatomy and Cell Biology, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan.
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133
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Fan W, Huang F, Li C, Qu H, Gao Z, Leng S, Li D, He H. Involvement of NOS/NO in the development of chronic dental inflammatory pain in rats. ACTA ACUST UNITED AC 2008; 59:324-32. [PMID: 19013482 DOI: 10.1016/j.brainresrev.2008.10.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 10/09/2008] [Accepted: 10/11/2008] [Indexed: 12/29/2022]
Abstract
Nitric oxide (NO) is believed to be an important messenger molecule in nociceptive transmission. To assess the possible roles of NO in trigeminal sensory system, we examined the distribution and density of histochemical staining for nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d), a marker for nitric oxide synthase (NOS), and immunohistochemical staining for c-Fos, a neuronal activity marker, in the trigeminal ganglion (TG) and trigeminal nucleus caudalis (Vc) following pulp exposure (PX) injured rats. The neurons innervating injured tooth in TG were labeled by the retrograde transport of fluoro-gold (FG). Teeth were processed for H&E staining. We found that NADPH-d activity increased significantly in the TG and Vc following PX pretreatment (7-28 days, especially in 21-28 days). Such changes were closely corresponding to the pattern of c-Fos detected by immunocytochemistry. The results demonstrate that PX-induced chronic pulpal inflammation results in significant alterations in the TG cells and in the Vc, and such changes may underlie the observed NADPH-d activity. It suggests that NOS/NO may play an active role in both peripheral and central processing of nociceptive information following chronic tooth inflammation.
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Affiliation(s)
- Wenguo Fan
- Department of Oral Anatomy and Physiology, Guanghua School of Stomatology, Sun Yat-sen University, 74 Zhongshan Road 2, Guangzhou, 510080, China
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134
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Moe K, Kettunen P, Kvinnsland IH, Luukko K. Development of the pioneer sympathetic innervation into the dental pulp of the mouse mandibular first molar. Arch Oral Biol 2008; 53:865-73. [DOI: 10.1016/j.archoralbio.2008.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2007] [Revised: 02/18/2008] [Accepted: 03/06/2008] [Indexed: 12/29/2022]
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135
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Kubo K, Shibukawa Y, Shintani M, Suzuki T, Ichinohe T, Kaneko Y. Cortical representation area of human dental pulp. J Dent Res 2008; 87:358-62. [PMID: 18362319 DOI: 10.1177/154405910808700409] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
To elucidate the dental pulp-representing area in the human primary somatosensory cortex and the presence of A-beta fibers in dental pulp, we recorded somatosensory-evoked magnetic fields from the cortex in seven healthy persons using magnetoencephalography. Following non-painful electrical stimulation of the right maxillary first premolar dental pulp, short latency (27 ms) cortical responses on the magnetic waveforms were observed. However, no response was seen when stimulation was applied to pulpless teeth, such as devitalized teeth. The current source generating the early component of the magnetic fields was located anterior-inferiorly compared with the locations for the hand area in the primary somatosensory cortex. These results demonstrate the dental pulp representation area in the primary somatosensory cortex, and that it receives input from intradental A-beta neurons, providing a detailed organizational map of the orofacial area, by adding dental pulp to the classic "sensory homunculus".
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Affiliation(s)
- K Kubo
- Department of Dental Anesthesiology, Oral Health Science Center, Laboratory of Brain Research, Tokyo Dental College, Chiba 261-8502, Japan.
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136
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137
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Nav1.7 expression is increased in painful human dental pulp. Mol Pain 2008; 4:16. [PMID: 18426592 PMCID: PMC2377237 DOI: 10.1186/1744-8069-4-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Accepted: 04/21/2008] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Animal studies and a few human studies have shown a change in sodium channel (NaCh) expression after inflammatory lesions, and this change is implicated in the generation of pain states. We are using the extracted human tooth as a model system to study peripheral pain mechanisms and here examine the expression of the Nav1.7 NaCh isoform in normal and painful samples. Pulpal sections were labeled with antibodies against: 1) Nav1.7, N52 and PGP9.5, and 2) Nav1.7, caspr (a paranodal protein used to identify nodes of Ranvier), and myelin basic protein (MBP), and a z-series of optically-sectioned images were obtained with the confocal microscope. Nav1.7-immunofluorescence was quantified in N52/PGP9.5-identified nerve fibers with NIH ImageJ software, while Nav1.7 expression in myelinated fibers at caspr-identified nodal sites was evaluated and further characterized as either typical or atypical as based on caspr-relationships. RESULTS Results show a significant increase in nerve area with Nav1.7 expression within coronal and radicular fiber bundles and increased expression at typical and atypical caspr-identified nodal sites in painful samples. Painful samples also showed an augmentation of Nav1.7 within localized areas that lacked MBP, including those associated with atypical caspr-identified sites, thus identifying NaCh remodeling within demyelinating axons as the basis for a possible pulpal pain mechanism. CONCLUSION This study identifies the increased axonal expression and augmentation of Nav1.7 at intact and remodeling/demyelinating nodes within the painful human dental pulp where these changes may contribute to constant, increased evoked and spontaneous pain responses that characterize the pain associated with toothache.
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138
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Nishikawa S. Histochemistry of nerve fibres double labelled with anti-TRPV2 antibodies and sensory nerve marker AM1-43 in the dental pulp of rat molars. Arch Oral Biol 2008; 53:859-64. [PMID: 18405879 DOI: 10.1016/j.archoralbio.2008.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 02/28/2008] [Accepted: 03/02/2008] [Indexed: 01/08/2023]
Abstract
AM1-43 can label sensory nerve fibres and sensory neurons. Permeation of non-selective cation channels of the nerve cell membrane is suggested to be the mechanism responsible for labelling. To identify these channels, two candidates, TRPV1 and TRPV2 were examined by immunocytochemistry in the dental pulp and trigeminal ganglion of rats injected with AM1-43. A part of AM1-43-labelled nerve fibres was also positive for anti-TRPV2 antibody but negative for anti-TRPV1 antibody in the dental pulp. In the trigeminal ganglion, a part of the neuron showed both bright AM1-43 labelling and anti-TRPV2 immunolabelling, but neurons double labelled with AM1-43 and TRPV1 were rare. These results suggest that TRPV2 channels, but not TRPV1 channels, contribute to the fluorescent labelling of AM1-43 in the dental pulp.
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Affiliation(s)
- Sumio Nishikawa
- Department of Biology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Yokohama 230-8501, Japan.
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139
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Avellán NL, Sorsa T, Tervahartiala T, Forster C, Kemppainen P. Experimental tooth pain elevates substance P and matrix metalloproteinase-8 levels in human gingival crevice fluid. Acta Odontol Scand 2008; 66:18-22. [PMID: 18320414 DOI: 10.1080/00016350701810658] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Tooth pain can induce a neurogenic inflammatory reaction in gingiva in association with local elevations of matrix metalloproteinase (MMP)-8, which is considered the major tissue destructive protease in gingival crevice fluid (GCF). The pro-inflammatory neuropeptides released by sensory nerves coordinate the activities of the immuno-effector cells and may influence the secretion of MMP-8. With this background, we studied whether experimental tooth pain can trigger changes in GCF levels of the neuropeptide substance P (SP) and MMP-8. MATERIAL AND METHODS The GCF SP levels of stimulated and non-stimulated teeth were analyzed for SP using a competitive enzyme immunoassay (EIA). The GCF MMP-8 levels were determined by quantitative immunofluorometric assay (IFMA). RESULTS Painful stimulation of the upper central incisor caused significant elevations in GCF SP and MMP-8 levels of the stimulated tooth. At the same time, the GCF SP and MMP-8 levels of non-stimulated control teeth were unchanged. CONCLUSIONS These data indicate that experimental tooth pain can induce local elevations of SP and MMP-8 levels in GCF simultaneously. This supports the possibility of a local neurogenic spread of inflammatory reactions from intrapulpal to surrounding periodontal tissues.
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140
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Nishikawa S. Styryl Pyridinium Dyes FM1-43 and AM1-43 for Visualization of Sensory Nerve Fibers and Cells in Dental and Craniofacial Tissues of Small Experimental Animals. J Oral Biosci 2008. [DOI: 10.1016/s1349-0079(08)80026-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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141
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142
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Nishikawa S. Developmental changes in pulpal sensory innervation of rat incisors and molars shown on a single injection of the fluorescent dye AM1-43. Anat Sci Int 2007; 82:227-32. [DOI: 10.1111/j.1447-073x.2007.00190.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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143
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Huang GTJ, Lee HW, Lee HS, Lee GH, Huh SY, Choi GW, Park SH. Localization of substance P-induced upregulated interleukin-8 expression in human dental pulp explants. Int Endod J 2007; 41:100-7. [PMID: 18005045 DOI: 10.1111/j.1365-2591.2007.01318.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To localize ex vivo expression of interleukin-8 (IL-8) induced by substance P (SP) in human dental pulps. METHODOLOGY Intact caries-free, freshly extracted third molars (n = 20) were collected from patients (15-25 years old). The teeth were split and pulpal tissue was obtained and stored in Dulbecco's modified Eagle medium. Human dental pulp tissue explants were stimulated with SP. Expression of IL-8 in pulp explants was detected and localized by immunohistochemistry. RESULTS Moderated IL-8 immunoreactivities were detected mainly in the cell-rich zone in pulp tissues 12 h after tumour necrosis factor alpha (TNF-alpha) stimulation (positive controls), whereas only weak IL-8 expression was observed in tissues stimulated with SP at the same time interval. These data did not differ from those in negative controls. Increased IL-8 expression in pulp explants after 24 h of SP stimulation was noted compared with negative controls and located in fibroblast-like cells, blood vessel-associated cells and extracellular matrix in the central zone and cell-rich zone of pulp explants. Tissues stimulated with TNF-alpha for 24 h (positive controls) revealed weak IL-8 immunoreactivities with altered cell morphology. CONCLUSIONS Substance P induces IL-8 expression and was located in fibroblast-like pulp cells, blood vessel-associated cells and extracellular matrix of human dental explants. These data support the hypothesis that neuropeptide (SP) coordinates the modulation of pulpal inflammation via up-regulating chemokine IL-8.
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Affiliation(s)
- G T-J Huang
- Division of Endodontics, College of Dental Surgery, Dental School, University of Maryland, Baltimore, MD, USA
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144
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Wells JE, Bingham V, Rowland KC, Hatton J. Expression of Nav1.9 Channels in Human Dental Pulp and Trigeminal Ganglion. J Endod 2007; 33:1172-6. [PMID: 17889684 DOI: 10.1016/j.joen.2007.05.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 05/10/2007] [Accepted: 05/14/2007] [Indexed: 11/28/2022]
Abstract
There is a higher incidence of local anesthetic failure in endodontic patients experiencing pulpal hyperalgesia. Up-regulation of Nav1.9, a voltage-gated sodium channel isoform, might play a key role in local anesthetic failure because Nav1.9 channels increase neuronal excitability and have low sensitivity to blockade by local anesthetics. Immunocytochemistry was used to examine Nav1.9 channel expression in axons of symptomatic (painful) versus asymptomatic human dental pulp and to determine Nav1.9 expression levels in neuronal somata of the human trigeminal ganglion. Nav1.9 channel immunoreactivity on pulpal axons was significantly increased in painful teeth. Nav1.9 channels were expressed in membranes and cytoplasm of human trigeminal ganglion neurons, with the highest expression in small neuronal somata. Nav1.9 expression in the trigeminal ganglion coupled with increased expression in symptomatic pulp might contribute to hypersensitivity of inflamed pulps and local anesthetic failure. Furthermore, the present study suggests that Nav1.9 channels are potential targets for novel anesthetics.
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Affiliation(s)
- Jason E Wells
- Southern Illinois University School of Dental Medicine, Alton, Illinois 62002, USA.
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145
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Grünheid T, Morbach BA, Zentner A. Pulpal cellular reactions to experimental tooth movement in rats. ACTA ACUST UNITED AC 2007; 104:434-41. [PMID: 17709075 DOI: 10.1016/j.tripleo.2007.03.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 03/08/2007] [Accepted: 03/19/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE The objective was to study the early cellular reactions of the dental pulp during experimental tooth movement. STUDY DESIGN A total number of 98 male rats were used. Tooth movement was induced for 1 to 168 hours by inserting elastic bands between maxillary first and second molars of animals, which were labeled with tritiated thymidine. Pathologic signs, macrophage content, and proliferation of fibroblasts and endothelial cells were assessed histologically on autoradiographs of second molar pulps. Data were analyzed using ANOVA with Tukey's test as post hoc pairwise comparison. RESULTS Pathologic signs and macrophage content generally increased with time after the induction of tooth movement. The proliferation of pulpal connective tissue progenitor cells and endothelial cells increased as a reaction to the force application. CONCLUSIONS Force-induced tooth movement may lead to extensive, however temporary, trauma of the pulpal tissues, which react with early wound-healing events, such as macrophage invasion, cell proliferation, and angiogenesis.
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Affiliation(s)
- Thorsten Grünheid
- Department of Orthodontics, Academic Center for Dentistry Amsterdam, Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands.
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146
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Localized increases in corticotropin-releasing factor receptors in pulp after dental injury. J Endod 2007; 33:1319-24. [PMID: 17963955 DOI: 10.1016/j.joen.2007.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 08/03/2007] [Accepted: 08/04/2007] [Indexed: 11/22/2022]
Abstract
Corticotropin-releasing factor (CRF) binds to membrane-bound CRF receptors (CRF-Rs). Among the actions mediated by activated CRF-Rs is beta-endorphin (END) release from immune cells, increasing peripheral antinociception. For assessment of inflammatory regulation of CRF-R expression, rats underwent pulp exposure of left, first mandibular molars and recovered for 6 days. Control pulpal tissue consisted of contralateral, uninjured molars and left, first mandibular molars of uninjured animals. Pulp tissue specimens were incubated with antibodies directed against CRF-R (both isoforms), neurofilament, CD45, and END. We observed (1) increases in pulp CRF-R immunoreactivity after injury, (2) increased CRF-R immunoreactivity expressed in 3 distinct zones in relation to the injury, and (3) increased CD45 and END immunoreactivity in regions surrounding the pulpal abscess. CRF-Rs might provide an additional target for novel analgesics to treat pulpal pain.
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147
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FRISTAD INGE, BLETSA ATHANASIA, BYERS MARGARET. Inflammatory nerve responses in the dental pulp. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1601-1546.2010.00247.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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148
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Wells JE, Rowland KC, Proctor EK. Hyperpolarization-activated channels in trigeminal ganglia innervating healthy and pulp-exposed teeth. Int Endod J 2007; 40:715-21. [PMID: 17645513 DOI: 10.1111/j.1365-2591.2007.01297.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AIM To use immunocytochemistry for determining the expression of HCN1, HCN2 and HCN3 (three subunits of the hyperpolarization-activated cyclic nucleotide-gated current channel) in rodent trigeminal ganglia (TG) that innervate healthy teeth and determine if expression of HCN subunits is increased in TG following pulp exposure. METHODOLOGY Pulps were exposed in right maxillary incisors of male Sprague-Dawley rats. After fixation, TG were removed, cryostat sectioned, and immunocytochemistry was utilized to study the expression of HCN1-3 subunits. Immunoreactivity of individual neurons from the maxillary region of the TG was determined with ImageJ software. Differences in the number immunopositive neurons amongst groups were tested for statistical significance with either a Yates or Pearson's chi-square or Fisher's exact probability tests depending on neuron sample size. Differences in the intensity of immunoreactivity between groups were tested for statistical significance with a Student's t-test. RESULTS The majority of TG neurons were immunopositive for HCN1-3. Moreover, statistically significant increases in the number of TG neurons immunopositive for HCN1 and the intensity of HCN1-3 immunoreactivity were observed within hours of exposing the tooth pulp. CONCLUSIONS HCN1-3 expression, as determined by immunocytochemistry, is increased within hours after injury. Given that I(h) can facilitate neuronal excitability, results of the current study suggest that antagonists to HCN1-3 subunits could work as analgesics in the alleviation of orofacial pain.
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Affiliation(s)
- J E Wells
- School of Dental Medicine, Southern Illinois University, Alton, IL 62002, USA.
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149
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Hahn CL, Liewehr FR. Innate Immune Responses of the Dental Pulp to Caries. J Endod 2007; 33:643-51. [PMID: 17509400 DOI: 10.1016/j.joen.2007.01.001] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 12/19/2006] [Accepted: 01/01/2007] [Indexed: 11/29/2022]
Abstract
Various cells and inflammatory mediators are involved in the initial pulpal responses to caries. This review focuses on the cellular, neuronal, and vascular components of pulpal innate responses to caries. Discussion will include dentinal fluid, odontoblasts, neuropeptides, and neurogenic inflammation, which are not classic immune components but actively participate in the inflammatory response as the caries progress pulpally. Summaries of innate immune cells as well as their cytokines and chemokines in healthy and reversible pulpitis tissues are presented.
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Affiliation(s)
- Chin-Lo Hahn
- Department of Endodontics, School of Dentistry, Virginia Commonwealth University, 520 North 12th Street, Richmond, Virginia 3298-0566, USA
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150
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Owatz CB, Khan AA, Schindler WG, Schwartz SA, Keiser K, Hargreaves KM. The incidence of mechanical allodynia in patients with irreversible pulpitis. J Endod 2007; 33:552-6. [PMID: 17437870 DOI: 10.1016/j.joen.2007.01.023] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 01/24/2007] [Accepted: 01/31/2007] [Indexed: 01/20/2023]
Abstract
The mechanisms of odontogenic pain are complex and incompletely understood. Cases of irreversible pulpitis are thought to represent a localized inflammatory response to bacterial challenge in dental pulp tissue. The presenting symptoms are classically defined by exaggerated painful episodes to thermal stimuli that may linger after cessation of the stimulus. However, the associated incidence of mechanical allodynia, defined as reduced mechanical pain threshold to masticatory forces, has not been characterized. This study evaluated pain intensity ratings and the presence of mechanical allodynia reported by 993 consecutive dental patients presenting for tooth extraction in a community health center. After clinical and radiographic examinations, the pulpal/periradicular diagnostic categories were normal pulp/normal periradicular (n=792 patients), irreversible pulpitis/normal periradicular (n=86), or irreversible pulpitis/acute periradicular periodontitis (n=115). The rank order for the mean values of pain intensity ratings was irreversible pulpitis/acute periradicular periodontitis > irreversible pulpitis/normal periradicular > normal/normal (p<0.05 for all comparisons). The incidence of mechanical allodynia in patients presenting with irreversible pulpitis was 57.2%, indicating that periradicular mechanical allodynia contributes to early stages of odontogenic pain because of inflammation of vital pulpal tissue.
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Affiliation(s)
- Christopher B Owatz
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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