Changes in the nerve's microenvironment and local inflammation resulting from peripheral nerve in... more Changes in the nerve's microenvironment and local inflammation resulting from peripheral nerve injury participate in nerve sensitization and neuropathic pain development. Taking part in these early changes, disruption of the blood–nerve barrier (BNB) allows for infiltration of immunocytes and promotes the neuroinflammation. However, molecular mechanisms engaged in vascular endothelial cells (VEC) dysfunction and BNB alterations remain unclear. In vivo, BNB permeability was assessed following chronic constriction injury (CCI) of the rat sciatic nerve (ScN) and differential expression of markers of VEC functional state, inflammation, and intracellular signaling was followed from 3 hours to 2 months postinjury. Several mechanisms potentially involved in functional alterations of VEC were evaluated in vitro using human VEC (hCMEC/D3), then confronted to in vivo physiopathological conditions. CCI of the ScN led to a rapid disruption of endoneurial vascular barrier that was correlated to a decreased production of endothelial tight-junction proteins and an early and sustained alteration of Hedgehog (Hh) signaling pathway. In vitro, activation of Toll-like receptor 4 in VEC downregulated the components of Hh pathway and altered the endothelial functional state. Inhibition of Hh signaling in the ScN of naive rats mimicked the biochemical and functional alterations observed after CCI and was, on its own, sufficient to evoke local neuroinflammation and sustained mechanical allodynia. Alteration of the Hh signaling pathway in VEC associated with peripheral nerve injury, is involved in BNB disruption and local inflammation, and could thus participate in the early changes leading to the peripheral nerve sensitization and, ultimately, neuropathic pain development.
The aim of this study was to place into perspective some factors that played an important role in... more The aim of this study was to place into perspective some factors that played an important role in the healing of periapical lesions after surgical endodontic procedures. Root-ends were sectioned at different angulations on models and analyzed by photoelastimetry. Results showed that a section of the root-end through a plane perpendicular to the long axis of the tooth offers a better distribution of the stresses exerted on the apical region that the use of an inclined plane. The biological implications of these results have led the authors to propose a plan of resection that is perpendicular to the long axis of the tooth instead of the inclined plane commonly used.
Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphy... more Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphyses of long bones, ribs, and pelvis and are rare in head and neck bones, with only 30 cases reported. The mandible is more affected than the maxilla. ES is also the second most common primary malignant bone tumor found in children, after leukemia and osteosarcomas, but they are rare in adults. The following is a report of a new case of ES localized in the maxilla occurring in a 25year-old man who had been misdiagnosed with an odontogenic infection. The patient was treated successfully, with a 2-year follow-up, by using a combination of aggressive systemic chemotherapy and surgery with primary reconstruction of the defect, avoiding the use of radiotherapy. (J Endod 2011;37:259-264)
Mineral trioxide aggregate (MTA) is considered at the present time as the gold standard for root-... more Mineral trioxide aggregate (MTA) is considered at the present time as the gold standard for root-end filling in endodontic surgery. However, this biocompatible material presents several drawbacks such as a long setting time and handling difficulties. The aim of this article is to present a new commercialized calcium silicate-based material named Biodentine with physical improved properties compared to MTA in a clinical application. Two endodontic microsurgeries were performed by using specific armamentarium (microsurgical instrumentation, ultrasonic tips) under high-power magnification with an operatory microscope. Biodentine was used as a root-end filling in order to seal the root canal system. The two cases were considered completely healed at 1 year and were followed for one more year. The 2-year follow-up consolidated the previous observation with absence of clinical symptoms and radiographic evidence of regeneration of the periapical tissues.
Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphy... more Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphyses of long bones, ribs, and pelvis and are rare in head and neck bones, with only 30 cases reported. The mandible is more affected than the maxilla. ES is also the second most common primary malignant bone tumor found in children, after leukemia and osteosarcomas, but they are rare in adults. The following is a report of a new case of ES localized in the maxilla occurring in a 25year-old man who had been misdiagnosed with an odontogenic infection. The patient was treated successfully, with a 2-year follow-up, by using a combination of aggressive systemic chemotherapy and surgery with primary reconstruction of the defect, avoiding the use of radiotherapy. (J Endod 2011;37:259-264)
Introduction: The purpose of this prospective study was to analyze the factors related to extract... more Introduction: The purpose of this prospective study was to analyze the factors related to extraction of endodontically treated teeth. Methods: One hundred nineteen cases of extraction of endodontically treated teeth were consecutively reviewed, and the following items were recorded: type of tooth; presence and type of coronal restoration; motive of consultation; reasons for extraction; patient's age, gender, level of education; smoking status. Association between factors was investigated with c 2 analysis. Results: Dental pain was the main motive for consultation (68.9%). The teeth most extracted were mandibular molars (51.3%), followed by maxillary molars (16.1%). First molars were the most frequently extracted (29.4%). Ninety-one teeth (76.5%) were restored coronally with or without post, and crowned teeth represented 5.9% of the sample. The reasons for extraction were periodontal disease (40.3%), endodontic failure (19.3%), vertical root fracture (13.4%), nonrestorable cuspid and crown fracture (15.1%), nonrestorable caries (5.2%), iatrogenic perforations and stripping (4.2%), and prosthetic (0.8%). Analysis between gender, smoking status, and education level showed no significant difference for reasons of extraction (P = .33 and .34). Conclusions: The mandibular first molar without crown was the most frequently extracted tooth. The main reasons for extractions were periodontal disease, endodontic failure, and nonrestorable tooth damage caused by fracture or caries. (J Endod 2011;37:1512-1515
Please cite this article as: Y. Boucher, C.T. Simons, M.I. Carstens, E. Carstens, Effects of gust... more Please cite this article as: Y. Boucher, C.T. Simons, M.I. Carstens, E. Carstens, Effects of gustatory nerve transection and/or ovariectomy on oral capsaicin avoidance in rats, PAIN (2014), doi: http://dx.
The aim of this study was to investigate the inferior alveolar nerve (IAN) and chorda tympani (CT... more The aim of this study was to investigate the inferior alveolar nerve (IAN) and chorda tympani (CT) projections onto gustatory neurons of the nucleus of the solitary tract (NST) in the rat by immunochemical and electrophysiological techniques. IAN afferents were retrogradely labeled. NST neurons were labeled either by retrograde tracer injection into the parabrachial nucleus (PBN) or by c-Fos mapping after CT activation. NST neurons responding to tastant stimulation were recorded in vivo before and after electrical stimulation of the IAN. Results from the immunolabeling approach showed IAN boutons "en passant" apposed to retrogradely labeled neurons from PBN and to CT-activated neurons in the NST. Recordings of single NST neurons showed that the electrical stimulation of the IAN significantly decreased CT gustatory responses. Analysis of these data provides an anatomical and physiological basis to support trigeminal dental and gustatory interactions within the brainstem.
Certain tastants inhibit oral irritation by capsaicin, whereas anesthesia of the chorda tympani (... more Certain tastants inhibit oral irritation by capsaicin, whereas anesthesia of the chorda tympani (CT) enhances oral capsaicin burn. We tested the hypothesis that tastants activate the CT to suppress responses of trigeminal subnucleus caudalis (Vc) neurons to noxious oral stimuli. In anesthetized rats, we recorded Vc unit responses to noxious electrical, chemical (pentanoic acid, 200 μm) and thermal (55 °C) stimulation of the tongue. Electrically evoked responses were significantly reduced by a tastant mix and individually applied NaCl, monosodium glutamate (MSG), and monopotassium glutamate. Sucrose, citric acid, quinine and water (control) had no effect. Pentanoic acid-evoked responses were similarly attenuated by NaCl and MSG, but not by other tastants. Responses to noxious heat were not affected by any tastant. Transection and/or anesthesia of the CT bilaterally affected neither Vc neuronal responses to electrical or pentanoic acid stimulation, nor the depressant effect of NaCl and MSG on electrically evoked responses. Calcium imaging showed that neither NaCl nor MSG directly excited any trigeminal ganglion cells or affected their responses to pentanoic acid. GABA also had no effect, arguing against peripheral effects of GABA, NaCl or MSG on lingual nocicepive nerve endings. The data also rule out a central mechanism, as the effects of NaCl and MSG were intact following CT transection. We speculate that the effect is mediated peripherally by the release from taste receptor cells (type III) of some mediator(s) other than GABA to indirectly inhibit trigeminal nociceptors. The results also indicate that the CT does not exert a tonic inhibitory effect on nociceptive Vc neurons.
Electrophysiological methods were used to investigate the effects of trigeminal nerve stimulation... more Electrophysiological methods were used to investigate the effects of trigeminal nerve stimulation or transection on responses of single gustatory neurons in the nucleus of the solitary tract (NTS) to tastants (NaCl, sucrose, citric acid, monosodium glutamate) in pentobarbital-anesthetized rats. Unilateral transection of the lingual nerve, or the mandibular branch of the trigeminal nerve, resulted in significant reductions (by 21 and 29%, respectively; P<0.01) in tastant-evoked responses, with no further effect following bilateral transection. Electrical stimulation of the central cut end of the mandibular nerve directly excited nine of 14 gustatory NTS units. For these units, central mandibular stimulation facilitated the tastant-evoked responses in six, depressed responses in three, and had no effect in five. Facilitation of tastant-evoked responses peaked 4 min after mandibular stimulation and recovered within 8 min. Electrical stimulation of the peripheral cut end of the mandibular nerve significantly reduced tastant-evoked responses in nine other NTS units, with a maximal reduction at 4 min post-stimulation followed by recovery. Stimulation of the superior cervical sympathetic ganglion did not affect NTS tastant-evoked responses. These results suggest the presence of complex central modulation of NTS neurons by trigeminal afferents, as well as a peripheral depressant effect on gustatory processing possibly mediated via neuropeptide release from trigeminal nerve endings in the tongue.
Changes in the nerve's microenvironment and local inflammation resulting from peripheral nerve in... more Changes in the nerve's microenvironment and local inflammation resulting from peripheral nerve injury participate in nerve sensitization and neuropathic pain development. Taking part in these early changes, disruption of the blood–nerve barrier (BNB) allows for infiltration of immunocytes and promotes the neuroinflammation. However, molecular mechanisms engaged in vascular endothelial cells (VEC) dysfunction and BNB alterations remain unclear. In vivo, BNB permeability was assessed following chronic constriction injury (CCI) of the rat sciatic nerve (ScN) and differential expression of markers of VEC functional state, inflammation, and intracellular signaling was followed from 3 hours to 2 months postinjury. Several mechanisms potentially involved in functional alterations of VEC were evaluated in vitro using human VEC (hCMEC/D3), then confronted to in vivo physiopathological conditions. CCI of the ScN led to a rapid disruption of endoneurial vascular barrier that was correlated to a decreased production of endothelial tight-junction proteins and an early and sustained alteration of Hedgehog (Hh) signaling pathway. In vitro, activation of Toll-like receptor 4 in VEC downregulated the components of Hh pathway and altered the endothelial functional state. Inhibition of Hh signaling in the ScN of naive rats mimicked the biochemical and functional alterations observed after CCI and was, on its own, sufficient to evoke local neuroinflammation and sustained mechanical allodynia. Alteration of the Hh signaling pathway in VEC associated with peripheral nerve injury, is involved in BNB disruption and local inflammation, and could thus participate in the early changes leading to the peripheral nerve sensitization and, ultimately, neuropathic pain development.
The aim of this study was to place into perspective some factors that played an important role in... more The aim of this study was to place into perspective some factors that played an important role in the healing of periapical lesions after surgical endodontic procedures. Root-ends were sectioned at different angulations on models and analyzed by photoelastimetry. Results showed that a section of the root-end through a plane perpendicular to the long axis of the tooth offers a better distribution of the stresses exerted on the apical region that the use of an inclined plane. The biological implications of these results have led the authors to propose a plan of resection that is perpendicular to the long axis of the tooth instead of the inclined plane commonly used.
Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphy... more Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphyses of long bones, ribs, and pelvis and are rare in head and neck bones, with only 30 cases reported. The mandible is more affected than the maxilla. ES is also the second most common primary malignant bone tumor found in children, after leukemia and osteosarcomas, but they are rare in adults. The following is a report of a new case of ES localized in the maxilla occurring in a 25year-old man who had been misdiagnosed with an odontogenic infection. The patient was treated successfully, with a 2-year follow-up, by using a combination of aggressive systemic chemotherapy and surgery with primary reconstruction of the defect, avoiding the use of radiotherapy. (J Endod 2011;37:259-264)
Mineral trioxide aggregate (MTA) is considered at the present time as the gold standard for root-... more Mineral trioxide aggregate (MTA) is considered at the present time as the gold standard for root-end filling in endodontic surgery. However, this biocompatible material presents several drawbacks such as a long setting time and handling difficulties. The aim of this article is to present a new commercialized calcium silicate-based material named Biodentine with physical improved properties compared to MTA in a clinical application. Two endodontic microsurgeries were performed by using specific armamentarium (microsurgical instrumentation, ultrasonic tips) under high-power magnification with an operatory microscope. Biodentine was used as a root-end filling in order to seal the root canal system. The two cases were considered completely healed at 1 year and were followed for one more year. The 2-year follow-up consolidated the previous observation with absence of clinical symptoms and radiographic evidence of regeneration of the periapical tissues.
Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphy... more Ewing's sarcoma (ES) belongs to the group II neuroectodermal tumors. They usually occur in diaphyses of long bones, ribs, and pelvis and are rare in head and neck bones, with only 30 cases reported. The mandible is more affected than the maxilla. ES is also the second most common primary malignant bone tumor found in children, after leukemia and osteosarcomas, but they are rare in adults. The following is a report of a new case of ES localized in the maxilla occurring in a 25year-old man who had been misdiagnosed with an odontogenic infection. The patient was treated successfully, with a 2-year follow-up, by using a combination of aggressive systemic chemotherapy and surgery with primary reconstruction of the defect, avoiding the use of radiotherapy. (J Endod 2011;37:259-264)
Introduction: The purpose of this prospective study was to analyze the factors related to extract... more Introduction: The purpose of this prospective study was to analyze the factors related to extraction of endodontically treated teeth. Methods: One hundred nineteen cases of extraction of endodontically treated teeth were consecutively reviewed, and the following items were recorded: type of tooth; presence and type of coronal restoration; motive of consultation; reasons for extraction; patient's age, gender, level of education; smoking status. Association between factors was investigated with c 2 analysis. Results: Dental pain was the main motive for consultation (68.9%). The teeth most extracted were mandibular molars (51.3%), followed by maxillary molars (16.1%). First molars were the most frequently extracted (29.4%). Ninety-one teeth (76.5%) were restored coronally with or without post, and crowned teeth represented 5.9% of the sample. The reasons for extraction were periodontal disease (40.3%), endodontic failure (19.3%), vertical root fracture (13.4%), nonrestorable cuspid and crown fracture (15.1%), nonrestorable caries (5.2%), iatrogenic perforations and stripping (4.2%), and prosthetic (0.8%). Analysis between gender, smoking status, and education level showed no significant difference for reasons of extraction (P = .33 and .34). Conclusions: The mandibular first molar without crown was the most frequently extracted tooth. The main reasons for extractions were periodontal disease, endodontic failure, and nonrestorable tooth damage caused by fracture or caries. (J Endod 2011;37:1512-1515
Please cite this article as: Y. Boucher, C.T. Simons, M.I. Carstens, E. Carstens, Effects of gust... more Please cite this article as: Y. Boucher, C.T. Simons, M.I. Carstens, E. Carstens, Effects of gustatory nerve transection and/or ovariectomy on oral capsaicin avoidance in rats, PAIN (2014), doi: http://dx.
The aim of this study was to investigate the inferior alveolar nerve (IAN) and chorda tympani (CT... more The aim of this study was to investigate the inferior alveolar nerve (IAN) and chorda tympani (CT) projections onto gustatory neurons of the nucleus of the solitary tract (NST) in the rat by immunochemical and electrophysiological techniques. IAN afferents were retrogradely labeled. NST neurons were labeled either by retrograde tracer injection into the parabrachial nucleus (PBN) or by c-Fos mapping after CT activation. NST neurons responding to tastant stimulation were recorded in vivo before and after electrical stimulation of the IAN. Results from the immunolabeling approach showed IAN boutons "en passant" apposed to retrogradely labeled neurons from PBN and to CT-activated neurons in the NST. Recordings of single NST neurons showed that the electrical stimulation of the IAN significantly decreased CT gustatory responses. Analysis of these data provides an anatomical and physiological basis to support trigeminal dental and gustatory interactions within the brainstem.
Certain tastants inhibit oral irritation by capsaicin, whereas anesthesia of the chorda tympani (... more Certain tastants inhibit oral irritation by capsaicin, whereas anesthesia of the chorda tympani (CT) enhances oral capsaicin burn. We tested the hypothesis that tastants activate the CT to suppress responses of trigeminal subnucleus caudalis (Vc) neurons to noxious oral stimuli. In anesthetized rats, we recorded Vc unit responses to noxious electrical, chemical (pentanoic acid, 200 μm) and thermal (55 °C) stimulation of the tongue. Electrically evoked responses were significantly reduced by a tastant mix and individually applied NaCl, monosodium glutamate (MSG), and monopotassium glutamate. Sucrose, citric acid, quinine and water (control) had no effect. Pentanoic acid-evoked responses were similarly attenuated by NaCl and MSG, but not by other tastants. Responses to noxious heat were not affected by any tastant. Transection and/or anesthesia of the CT bilaterally affected neither Vc neuronal responses to electrical or pentanoic acid stimulation, nor the depressant effect of NaCl and MSG on electrically evoked responses. Calcium imaging showed that neither NaCl nor MSG directly excited any trigeminal ganglion cells or affected their responses to pentanoic acid. GABA also had no effect, arguing against peripheral effects of GABA, NaCl or MSG on lingual nocicepive nerve endings. The data also rule out a central mechanism, as the effects of NaCl and MSG were intact following CT transection. We speculate that the effect is mediated peripherally by the release from taste receptor cells (type III) of some mediator(s) other than GABA to indirectly inhibit trigeminal nociceptors. The results also indicate that the CT does not exert a tonic inhibitory effect on nociceptive Vc neurons.
Electrophysiological methods were used to investigate the effects of trigeminal nerve stimulation... more Electrophysiological methods were used to investigate the effects of trigeminal nerve stimulation or transection on responses of single gustatory neurons in the nucleus of the solitary tract (NTS) to tastants (NaCl, sucrose, citric acid, monosodium glutamate) in pentobarbital-anesthetized rats. Unilateral transection of the lingual nerve, or the mandibular branch of the trigeminal nerve, resulted in significant reductions (by 21 and 29%, respectively; P<0.01) in tastant-evoked responses, with no further effect following bilateral transection. Electrical stimulation of the central cut end of the mandibular nerve directly excited nine of 14 gustatory NTS units. For these units, central mandibular stimulation facilitated the tastant-evoked responses in six, depressed responses in three, and had no effect in five. Facilitation of tastant-evoked responses peaked 4 min after mandibular stimulation and recovered within 8 min. Electrical stimulation of the peripheral cut end of the mandibular nerve significantly reduced tastant-evoked responses in nine other NTS units, with a maximal reduction at 4 min post-stimulation followed by recovery. Stimulation of the superior cervical sympathetic ganglion did not affect NTS tastant-evoked responses. These results suggest the presence of complex central modulation of NTS neurons by trigeminal afferents, as well as a peripheral depressant effect on gustatory processing possibly mediated via neuropeptide release from trigeminal nerve endings in the tongue.
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