Blast injuries to carotid artery: development of a finite element model and biomechanical analysis / 中华创伤杂志

Objective To construct a three-dimensional finite element model to investigate the biomechanical mechanism of carotid blast injuries.Methods Based on the head and neck CT angiography data of a healthy male volunteer,the 3D geometric model was extracted by Mimics software.The 3D solid model was obtained by fitting the geometric model to the non-uniform rational B-splines (NURBS) by Geomagic Studio software.The mesh of blood vessels,blood and soft tissue was divided by HyperMesh software to obtain the three-dimensional finite element model of the carotid artery.The material parameters and boundary conditions were set,and the vessel wall rupture damage threshold was 1 MPa.The dynamic process of carotid injury caused by MK3A2 grenade explosion shock wave at the distance of 60,70 and 80 cm to the neck was simulated using the LS-DYNA,generating the shock waveform and peak overpressure.The stress cloud map was used to analyze the stress distribution and damage morphology,and the stress curve was used to analyze the mechanical changes.Results The peak values of shock wave overpressure were 0.45,0.63 and 0.96 MPa at the distance of 80,70 and 60 cm away from the explosion center,respectively.At 80 cm,the peak stress of vessel wall was 0.43 MPa,and the vessel wall was not ruptured;at 70 cm,the peak stress of anonyma was greater than 1 MPa,which resulted in small rupture;at 60 cm,the peak stress of both anonyma the ascending aorta were greater than 1 MPa,leading to obvious rupture.The root part of the common carotid artery,anonyma and the arch of the aorta were high stress concentration areas,manifested as high-prevalence areas of damage and rupture.Conclusions The finite element model of explosive carotid artery injury is successfully constructed,which can be used to analyze the mechanical response and damage mechanism of carotid blast injuries.The main cause of injury and rupture is that the sudden change of stress in the process of explosion shock reaches or exceeds the threshold of vascular wall injury.Carotid artery rupture will occur when the vessel wall stress peak is greater than 1 MPa at 60 and 70 cm away from the explosion center,providing references for the clinical treatment and injury prevention.

Application of computer-aided design and 3D printing model in operation for complex mandibular fractures / 中华创伤杂志

Objective To investigate the value of computer aided design and 3D printing model in operation for complex mandibular fractures.Methods The clinical data of 136 patients with complex mandibular fractures treated from June 2006 to June 2016 were retrospectively analyzed.The patients were divided into 3D group (n =28) and conventional group (n =108) based on the use of computer aided design and 3D printing model.There were 24 males and four females in 3D group,with the age of (33.8 ± 15.4) years.There were 91 males and 17 females in conventional group,with the age of (30.3± 11.9)years.The 3D group used computer aided design and 3D printing model to develop the surgical plan,and the conventional group used traditional CT scan image data.The operation time,intraoperative blood loss,incidence of postoperative adverse events,and the distance differences between the ipsilateral and the five contralateral maxillofacial markers were compared between the two groups (△L1:the difference between the mandibular angle point and the condyle apex;△L2:the difference between the mandibular angle point and the chin vertex;△L3:the difference between the apex of the chin and the apical point;△L4:the difference between the inner mandibular angle point and the Inferior alveolar margin point;△L5:the distance between the inner mandibular angle and the sagittal plane).Results The operation time in the 3D group and the conventional group were 155 (126.25,183.75)min and 235 (156.25,268.75)min,respectively.The intraoperative blood loss in the 3D group and the conventional group were 100 (50.0,187.5) ml and 125 (100.0,200.0) ml,respectively.In the 3D group,one patient had mild occlusion disorder.In the conventional group,4 patients had postoperative infection,1 repulsion reaction of internal fixation device,and 19 mild occlusion disorder.The differences between the two groups in operation time and postoperative adverse events were statistically significant (P ＜ 0.05),but there was no significant difference in intraoperative blood loss (P ＞ 0.05).There was no significant difference between the ipsilateral △L and contralateral △L in two groups (P ＞ 0.05).No significant difference in △L4 was found (P ＞ 0.05),but there were significant differences in △L1,△L2,△L3,and △L5 between the two groups (P ＜0.05).Conclusion For patients with complex mandibular fractures,the use of computer-aided design and 3D printing model can helps shorten operation time,reduce postoperative adverse events and hence improve the fracture reduction outcome.

The effects of BMP9 combined with NGF on the osteogenic differentiation of C3H10T1/2 mesenchymal stem cells / 实用口腔医学杂志

Objective:To investigate the effects of BMP9 combined with NGF on the osteogenic differentiation of mesenchymal stem cells(MSCs).Methods:Recombinant BMP9 adenovirus was transfected into C3H10T1/2 cells.The cells were treated by GFP,NGF,BMP9 and BMP9 + NGF respectively.The expression level of COL1,RUNX2 was detected by RT-PCR and Western blot,ALP activity was examined by ALP kit 3,12,24,48 hours,3 and 7 days after treatment,respectively.Results:The ALP activity of BMP9 + NGF group was the highest among the 4 groups.The difference in the groups firstly appeared at 3 h after treatment.The highest expression level of RUNX2 and COL1 was detected in BMP9 + NGF group.Conclusion:NGF and BMP9 may synergisticly promote osteogenic differentiation at the early stage of osteogenic induction of C3H10T1/2 cells.

Calcitonin gene-related peptide-induced osteogenic differentiation of mouse bone marrow stromal cells through Hippo pathway in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>Previous studies have clarified that calcitonin gene-related peptide (CGRP) can promote the biologi- cal activity of osteoblasts. To further reveal the role of CGRP in bone repair, we studied its influence on osteogenic differentia- tion of mouse bone marrow stromal cells (BMSCs) and initially explored the effect of the Hippo signaling pathway with this process.</p><p><b>METHODS</b>BMSCs were induced to osteogenic differentiate osteoblasts by different concentrations of CGRP for a screening of the optimal concentration. CGRP was added in BMSCs, then the activity of alkaline phosphatase (ALP) and the number of mineralized nodules were examined by specific ALP kits after 48 hours and alizarin red staining fluid after 7 days, respectively. The protein expression of p-Mst1/2 was measured by Western blot. Verteporfin was used to block the downstream Yap signaling. The mRNA expression of collagen type I (Col I) and runt-related transcription factor 2 (Runx2) were detected by reverse transcription-polymerase chain reaction.</p><p><b>RESULTS</b>Compared to the blank group, different concentrations of CGRP (10⁻⁹, 10⁻⁸, 10⁻⁷ mol · L⁻¹), especially 10⁻⁸ mol · L⁻¹, significantly increased the ALP activity of BMSCs (P < 0.05). Alizarin red staining also showed more mineralized nodules in 10⁻⁸ mol · L⁻¹ group. The expression of p-Mst1/2 increased in the CGRP group (P < 0.05). Verteporfin treatment effectively decreased the mRNA expression of Runx2 and Col I (P < 0.05).</p><p><b>CONCLUSION</b>The Hippo signaling pathway plays a role in CGRP-induced osteogenic differentiation in mouse BMSCs.</p>

Experimental study on establishment of a 3D finite element model of human craniomaxillofacial region and its use in impact injury simulation / 中华创伤杂志

Objective To develop a 3D finite element model for the human craniomaxillofacial region in an attempt to offer basis to the research of simulation of craniomaxillofacial injury.Methods A healthy adult male was submitted to head CT scan, and the data was imported into the Mimics 15.0 software for threshold segmentation and 3D reconstruction according to the classifications of bone tissue, skin tissue and subcutaneous tissue.The reconstruction data was imported into 3D reverse software Geomagic Studio 2012, and the images were optimized and the 3D model was generated.The three parts of the model were fitted according to the actual proportion using the 3D control software Solidworks 14.0, and then the boundary conditions were derived.Hypermesh 12.0 finite element processing software was used to build the volume mesh, and the model was established.Each layer of the model was given to the material parameters, and the simulation conditions were provided to test the model.Results This model was completely composed of volume meshes, including 214,250 hexahedral meshes and 411,920 nodes.This model can clearly show the stress distribution, the trend of fracture line, the displacement of fracture block of soft and hard tissue during the simulation, and the results are consistent with clinical practice.Conclusion A three-dimentional finite element model with good performance is established, which can be used for biomechamics simulation analysis of multiple sites on the head or the whole structure, and has a certain significance in clinical and scientific research.

Biomechanical study on the impact injure of human mandible by finite element method / 实用口腔医学杂志

Objective:To investigate biomechanical changes of mandible in the impact injure simulated by finite element method (FEM).Methods:Mimics and Comsol software were used to build a FEM of human craniofacial bone based on CT scan data of a normal adult.LS-DYNA and Hypermesh software were used to simulate the impact with different quality,velocity and angulation pro-duced injures of human mandible,the biomechanical parameters of the mandible in the impact injury process were analysed.Results:A FEMof human maxillofacial bone was established,and the dynamic process of different impact force produced damage was simula-ted.Mandibular chin,angle and condylar neck was the stress concentrated area in the process of mandible injury.There was higher stress peak at the site which was closer to the impact position,the stress peak arrival time was also earlier.When the impactor with the same quality,the bigger the velocity,the greater the stress peak.When the impactor with the same velocity,the bigger the quali-ty,the greater the stress peak.When the impactor with the same velocity and quality,there was greater stress peak under the impact to mandible from angulation of 0 degree.Stress transfered to the surrounding bone from the impact position radially and gradually re-duced.The bone area with small cross-section was prone to high stress and more serious damage.Conclusion:The quality,the ve-locity,the impact angle and the impact site are the factors affecting the severity of impact injury.

Experimental study on the effect of RAMP1 -siRNA on CGRP-induced proliferation of MG-63 cells / 实用口腔医学杂志

Objective:To investigate the effect of blocking the expression of receptor activity modifying protein 1 (RAMP1 )on calcito-nin gene-related peptide(CGRP)-induced MG-63 cell proliferation.Methods:RAMP1 siRNA was synthesized and screened by tran-scription in vitro.The subcultured MG-63 cells were divided into the following groups:RAMP1 siRNA interference group,empty vector group and blank control group.The mRNA expression and the membrane distribution changes of the calcitonin receptor-like receptor (CRLR)and the receptor component protein (RCP)in MG-63 cells were examined by real-time PCR and immunofluorescence method respectively.Results:RAMP1 and CRLR mRNA and the fluorescence intensity of MG-63 cells decreased after transfection by RAMP1 siRNA(P <0.05).In RAMP1 interference group,the expression of RCP mRNA and the fluorescence intensity were higher than those in the other two groups(P <0.05).After RAMP1 siRNA interference,the proliferation of MG-63 cells was inhibited(P <0.05). Conclusion:RAMP1 siRNA transfection may reduce CRLR expression and inhibite the proliferation of MG-63 cell.

Modern concepts of trauma care and multiple trauma management in oral and maxillofacial region / 华西口腔医学杂志

Multiple trauma management requires the application of modem trauma care theories. Optimal treatment results can be achieved by reinforcing cooperation and stipulating a treatment plan together with other disciplines. Based on modem theories in trauma care and our understanding of the theoretical points, this paper analyzes the injury assessment strategies and methods in oral and maxillofacial multiple trauma management. Moreover, this paper discusses operating time and other influencing factors as well as proposed definitive surgical timing and indications in comprehensive management of oral and maxillofacial multiple trauma patients associated with injuries in other body parts. We hope that this paper can help stomatological physicians deepen their understanding of modem trauma care theories and improve their capacity and results in the treatment of oral and maxillofacial multiple trauma.

Experimental study on the effects of the nerve growth factor regulating calcitonin gene-related peptide in promoting the proliferation of MG-63 in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the nerve growth factor (NGF) regulating the expression of calcitonin gene-related peptide (CGRP) in promoting the proliferation of osteoblast-like cell (MG-63) and thus illustrate the mechanism of the NGF in wound healing.</p><p><b>METHODS</b>Different concentrations of NGF were used to stimulate MG-63. The expression of CGRP was detected by real-time quantitative polymerase chain reaction (RT-QPCR) and enzyme-linked immunosorbent assay after 1, 2, 3, and 4 days. The proliferation of MG-63 was detected by cell counting kit-8 (CCK-8). The expression of CGRP mRNA and the proliferation of MG-63 were then detected by RT-QPCR and CCK-8 after adding the NGF receptor blocker.</p><p><b>RESULTS</b>Compared with the blank control group, the expression of CGRP significantly increased by stimulating the NGF. The expression of CGRP was positively related to the concentration of NGF (P<0.05). Moreover, the expression of CGRP increased by prolonging the NGF stimulation time. The proliferation of MG-63 increased after stimulating the NGF (P<0.05). After adding the NGF receptor blocker, the expression of CGRP and the proliferation of MG-63 correspondingly decreased (P<0.05).</p><p><b>CONCLUSION</b>NGF can up-regulate the expression of CGRP and increase the proliferation of MG-63. Therefore, NGF plays a significant role in wound healing.</p>

Effective evaluation of autogenous coronoid process reengineering condylar arthroplasty with simultaneous genioplasty / 重庆医学

Objective To evaluate the clinical effects of autogenous coronoid process reengineering condylar arthroplasty with simultaneous genioplasty for the correction of temporomandibular joint(TMJ)ankylosis accompanying micrognathia.Methods 21 cases of TMJ ankylosis with micrognathia from July 2003 to January 2012 were treated by autogenous coronoid process re-engineering condylar arthroplasty with simultaneous genioplasty.The follow-up period was 24 months to 8 years.TMJ function, mouth opening,occlusion,facial contour and the imaging manifestations were evaluated.Results After observation of follow-up,19 cases were improved obviously in the mandibular movement and mouth opening.Two cases had the recurrence of TMJ ankylosis. The facial appearance in all cases was significantly improved compared with before operation and the occlusal relationship had no large change compared with before operation.The coracoid process and mandibular ramus reached bone union with good reconstruc-tion by the panoramic radiographs.Compared with preoperation;the cephalometric results showed that the facial contour and process had statistical differences between postoperation and preoperation(P <0.05).Conclusion Autogenous coronoid process re-engineering condylar arthroplasty with simultaneous genioplasty can treat TMJ ankylosis accompanying micrognathia.

Epithelioid hemangioendothelioma in parotid gland misdiagnosed as parotid gland cyst with hemorrhage in 1 case / 实用口腔医学杂志

The report presents a case of epithelioid hemangioendothelioma in parotid gland misdiagnosed as parotid gland cyst with hemor-rhage.Based on the literature review,clinical characteristics,diagnosis and treatment of the disease are discussed.

Research progress of the pathophysiological role of receptor activity modifying proteins / 国际生物医学工程杂志

Receptor activity modifying proteins (RAMPs) is a kind protein with transmembrane functionality.RAMPs can interact with TypeⅡ G protein coupled receptors (GPCRs) such as calcitonin gene-related peptide receptor (CGRPR),calcitonin receptor (CTR) and calcitonin receptor-like receptor (CRLR),to form a stable heterodimer expression on the cell membrane.Different RAMPs can combine with CRLR or CTR to produce different receptor phenotypes with ligand-specific affinity and thus can decide biological effect of the receptors.In addition,RAMPs can also interact with other GPCRs,which promise broader application in function regulation of G-proteincoupled receptor of RAMPs'.RAMPs' regulation of GPCRs depends on its molecular basis.Our studies of RAMPs provides a new perspective to further researches on GPCRs functionality and CGRP signal transduction.

Effects of the activity of superoxide dismutase in blood serum and gingival tissues of rabbit in periodontitis model after hypoxia exposure at high altitude / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the activity of superoxide dismutase (SOD) in rabbit periodontitis model in normoxia and hypoxia environment, and to research the pathogenesis of periodontal diseases at high altitude.</p><p><b>METHODS</b>Fourty male rabbits were randomly divided into four groups: Normoxia control group, normoxia periodontitis group (periodontitis models), hypoxia control group, hypoxia periodontitis group (periodontitis models). The periodontitis models were established by ligating the two central incisors of mandible and raised by periodontitis diets. The weights of four groups were dynamically observed. After eight weeks, the clinical periodontal indexes and the activity of total-SOD (T-SOD) in blood serum and gingival tissues in all groups were detected.</p><p><b>RESULTS</b>The activity of T-SOD of hypoxia periodontitis group was significantly lower than normoxia periodontitis group and hypoxia control group (P<0.05), the weights and clinical periodontal indexes were also dramatically different (P<0.01). The activity of SOD in serum was positively correlated with the gingival tissues (r=0.846, P<0.01), and they both negatively correlated with AL (r=-0.980, -0.804, P<0.01).</p><p><b>CONCLUSION</b>The growth state of the body and the balance of bioconversion were affected in hypoxia environment when exposed at high altitude. The activity of SOD in total body and local tissues were decreased, thus the superoxide free radicals were accumulated in the body, especially in local periodontal tissues. Therefore it can accelerate and aggravate the destruction of periodontal tissues.</p>

Clinical application of mimics software in three dimensional CT images for treatment of zygomatic complex fracture / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study a reliable CT measuring method for quantitative diagnosis of unilateral zygomatic complex fracture and operation guiding.</p><p><b>METHODS</b>20 zygomatic complex fracture patients needed operation were collected, three dimensional CT images of all patients were measured and analyzed by Mimics software before operation. Standard anatomy points of bilateral zygomatic complex and adjacent bone were selected, then the distance of two same selected points and the angles of three same selected points were measured by Mimics software. Compared to uninjured side, the different value of the distance and the angle of injured side zygomatic complex were acquired, zygomatic complex fractures were operated based on the different value. All patients were examined by three dimensional CT postoperatively, and the different value of the distance and the angle of both side were measured using same method to pre-operation. Therapy effects were analyzed based on the data of different value of the distance and the angle.</p><p><b>RESULTS</b>1) The displacement of zygoma of most patients was backward and inward. The different value of the distance between uninjured and injured side was less than 2 mm, and the different value of the angle was less than 1 degrees. All patients reached the three-dimensional symmetric, surgical results were satisfactory in recovery of occlusion and mouth opening. 2) The zygomatic arch protrusion angle was about 138.50 degrees +/- 1.15 degrees, zygomatic prominent angle was about 132.72 degrees +/- 0.89 degrees. The two data were normal distribution.</p><p><b>CONCLUSION</b>Three dimensional CT measurements of zygomatic complex can be achieved for the quantitative measurement of spatial displacement, and have directive significance for the reduction of the zygomatic complex fractures.</p>

The effects of transection of inferior alveolar nerve on inflammatory factors during haematoma phases in mandibular defect healing of denervated rabbits / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the effects of transection of inferior alveolar nerve (IAN) on the healing of mandibular fracture by investigating the changes of inflammatory factors expression, including tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1) and interleukin-6 (IL-6) in the denervated rabbits' bony callus.</p><p><b>METHODS</b>50 Chinese rabbits were randomly divided into the experimental group and control group, the experimental group underwent mandibular fracture and transection of IAN and the control group underwent mandibular fracture only. The bony callus were collected at 1, 2, 3, 5 and 7 d after operation, respectively. The expression of TNF-alpha, IL-1 and IL-6 in callus was detected by enzyme linked immunosorbent assay (ELISA), and the mRNA of TNF-alpha was detected by reverse transcription-polymerase chain reaction(RT-PCR).</p><p><b>RESULTS</b>In the experimental group, at the 1st day after operation, the expression of TNF-alpha (75.1%), IL-1 (68.3%) and IL-6 (72.7%) was lower than that in control group (P < 0.05). At the 2nd day, the expression of IL-1 (75.5%) was still lower than that in control group, but the expression of TNF-alpha was higher than that in control group. In the next observation points, all inflammatory factors decreased, and there was no difference between experimental and control groups. In RT-PCR, the detection of TNF-alpha mRNA in the experimental group was lower than that in control group.</p><p><b>CONCLUSION</b>In the haematoma of mandibular fracture healing, transection of IAN causes neurohumor decrease, depression and delay of inflammatory reaction. It is unfavorable to fracture healing.</p>

Effects of rhBMP_2 on differentiation of human dental pulp stem cells and expression of Delta protein in vitro / 吉林大学学报(医学版)

Objective To investigate the effects of rhBMP2 on the differentiation of human dental pulp stem cells and expression of Delta protein in vitro. provide a theoretical basis for research on human dental pulp stem cells. Methods Monocell suspension was separated from the human adult dental pulp with collagenase Ⅰ and dispase digestion.Clonogenic cells were observed under light microscope and the expressions of surface markers were determined with immunofluorescence. divided into experimental group (containing 50 ?g?L-1rhBMP2 in the culture medium) and negative control group (containing culture medium only).alkaline phosphatase and the expression of Delta proterin of the cells at at passage 5 were detected.Results The human dental pulp stem cells showed colony growth,the nestin and vimentin staining were positive by immunohistochemical staining.STRO-1 was positive in cells by immunofluorescence.Compared with negative control group, the activities of alkaline phosphatase increased after treatment with rhBMP2 for 7,14 and 21d(P

Ultrastructure changes of cochlea and cochlear nerve after maxillofacial blast wound / 中国组织工程研究

BACKGROUND: There have been reports about the cochlea injury after high-velocity projectile wounding. The effect on ultrastructure of cochlea after blast was still unclear.OBJECTIVE: To investigate ultrastructural changes of cochlea and cochlear nerve after maxillofacial blast wound.DESIGN:A randomized controlled observational trail with dogs as subjects.SETTING: Otolaryngeal Department and Maxillofacial Surgery Laboratory of the Third Military Medical University of Chinese PLA.MATERIALS: The study was conducted from August 1995 through July 1997. The animal model in maxillofacial blast wound was established in Animal Center of Xinqiao Hospital of the Third Military Medical University of Chinese PLA. Specimens were treated in Maxillofacial Laboratory and observed in Electron Microscope Laboratory. Totally 15 dogs of either sex (weighting 9. 5 - 13.5 kg, mean 11.3 kg ) were randomly divided into three groups with 5 in each group. Two groups served as trauma groups 1 and 2 and the other group as control.METHODS: The maxillary and mandibular regions of 10 dogs in trauma groups were wounded by model 8 cardboard-shelled detonators to establish animal model of maxillofacial blast wound. At the 1st and 6th hour after trauma the wounds were examined and specimens of cochlea and cochlear nerve were dissected out for electron microscopic observation to study the ultrastructural changes. The specimens in the control group were treated the same way as those in the trauma groups except for blast injury.RESULTS: After wounded, the cochlea and cochlear nerve in the early period manifested cilia disorder, edema of the nerve and mitochondrial degeneration. At the 6th hour after trauma there were extensive degeneration in cochlea and cochlear nerve, cilia fallen off hair cells and dissolution of the structures in nerve sheath.CONCLUSION: The ultrastructural changes of cochlea and cochlear nerve are severed as a result of maxillofacial blast wound, but in early period the injury is reversible. So it is very important that early cure should be emphasized in treatment.

Clinical study of the effect of calcium hydroxide on root canal disinfection / 第三军医大学学报

Objective To compare the disinfectant effects of calcium hydroxide and traditional formaldehyde and cresol(FC) on the intracanal medicament in infected single rooted teeth. Methods A total of 84 single rooted teeth with chronic apical periodontits were randomly selected for the disinfection with calcium hydroxide or FC in root canal after the root canals were cleared routinely. Samples were taken before and after root canal disinfection a week later. The number and species of bacteria in the root canal and the change of clinic signs and symptoms were observed. All the patients were followed up for one year. Results The number and species of bacteria in the root canal decreased significantly and there was significant difference between the two groups ( P 0.05). Conclusion Calcium hydroxide is an effective disinfectant in root canal therapy.

Effect of IGF-1 and bFGF on differentiation of human dental pulp stem cells in vitro / 第三军医大学学报

Objective To investigate the effect of insulin-like growth factor-1(IGF-1) and basic fibroblast growth factor (bFGF) on the differentiation of human dental pulp stem cells in vitro. Methods Mono-cell suspension was separated from the human adult dental pulp with collagenase Ⅰ and dispase digestion. Colony-forming efficiency of cells was calculated. Cells were observed under an invert microscope. Dentin sialoprotein (DSP), dentin matrix protein 1 (DMP-1) and dentin sialophosphoprotein (DSPP) mRNA of the 3rd passage cells induced with IGF-1 and bFGF in vitro were detected by immunohistochemistry and RT-PCR. Results Clonogenic cells were obtained from dental pulp and colony-forming efficiency of cells was 2.6-3.5 colonies/10 4 cells. Human specific DSP, DMP-1 protein and DSPP mRNA expressed in colony-forming cells after 7 d of induction with IGF-1 and bFGF in vitro. Conclusion Adult stem cells might exist in human dental pulp. Dental pulp stem cells could differentiate into odontoblast under the induction of IGF-1 and bFGF.

Subtance P expression in mandibular callus after section / 第三军医大学学报

Objective To study the effect of sensory nerve on mandibular fracture through detecting the expression of SP in mandibular callus after inferior alveolar nerve (IAN)section. Methods Thirty-two Chinese rabbits were divided into two groups. All rabbits suffered from a standardized fracture in the left mandibula, and half of them underwent IAN section. The callus were stained by hematoxylin and immunochemistry to observe the expression of SP in callus and fracture healing process. Results There were a larger quantity of fibrous callus formation, relatively immatured woven bone callus, lower proportion between immatured bone callus and new bone callus and less immunoreactive substance P in the group with IAN section than in the group with intact IAN at day 7, 14, 21, 28 after operation. Strong immunoreaction of substance P occurred mainly in bone marrow on day 28 postoperatively in both groups. Conclusion Sensory nerve may involve in the process of callus formation at early stage and bone remodeling at late stage so that sensory nerve injury influences the quantity and quality of new callus formation. It seems that neural involvement in bone healing is related to the local concentration of SP in the callus.