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@#Dental caries, trauma, and iatrogenic stimulation can cause damage to the dentin-pulp complex. Preserving the viable pulp and promoting damage repair of the dentin-pulp complex is of great clinical significance at present. In recent years, studies have found that various small molecular compounds can regulate inflammation, promote the migration, proliferation, and differentiation of dental pulp stem cells, promote blood vessel, nerve regeneration and other biological processes by regulating key intracellular signaling pathways and metabolic pathways, and could thereby promote damage repair of the dentin-pulp complex. The objective of this paper is to review recent research on various small molecular compounds used in promoting the repair of dentin-pulp complex.
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Pulp necrosis can cause increased tooth fragility and easy fracture, and hinder the sustainable development of young permanent teeth. Therefore, pulp regeneration therapy has important clinical significance. However, due to the complicated and varied anatomical structure of the pulp tissue, and various components such as nerves and blood vessels, there are many challenges in dental pulp regeneration strategy. In this paper, the recent research progress in the application of dental pulp tissue construction and transplantation by tissue engineering method was reviewed, and the selection of suitable scaffold materials and the construction of dental pulp tissue were discussed. The functional characteristics of scaffold materials were described,such as sodium alginate, chitosan, hyaluronic acid, collagen, gelatin, fibrous protein, silk fibroin, peptides and self-assembled peptides, polylactic acid, polyglycolic acid and their copolymers. In addition, the functions and characteristics of these materials were briefly introduced, as well as the functional modification with growth factors and other biological matrix extract involvement, and functional improvement of the composite scaffolds with complementary effects.Combined with the requirements of clinical operability, the composition design and functional characteristics of the injectable hydrogel scaffolds consisted of hydrophilic composite materials and/or modified with hydrophilic groups were also discussed.This review paper would be useful in providing some reference for the future research and exploration of dental pulp regeneration.
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Objective: To investigate low intensity pulsed ultrasound (LIPUS) on the expression of L-type calcium ion channels(cav1. 2) and Na +-Ca2 + exchangers(NCX1) during dentin-pulp complex injury and repair in rats. Methods: Cavity preparation was made on the upper right first molar of 40 male adult SD rats,20 of them and the upper left first molar of the other 20 were randomly chosen for LIPUS irradiation(frequency: 1. 5 MHz,200 μs pulses,pulse repetition frequency: 1 KHz,ISATA 30 mW/cm2,20 min /d),so the animals were randomly allocated into 4 groups(n = 10): Control group,LIPUS group,cavity preparation group and cavity preparation + LIPUS group. At 1,3,7,14 d post-irradiation the rats were sacrificed respectively for HE stain and immunohistochemical analysis. Results: Reparative dentin formation was observed at 14 days after cavity preparation and LIPUS irradiation,the expression of Cav1. 2(L-type) and NCX1 in this group were increased significantly at day 1 and day 3. Compared with the control group, the expression of Cav1. 2 in LIPUS group increased at day 1 post-irradiation. Conclusion: LIPUS may enhance tertiary dentin formation and up-regulate the expression of Cav1. 2 and NCX1 at the early period of dentin injury.
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Age estimation is a hot and difficult issue in forensic practice. Teeth are the most solid organs in human body and can be kept in vitro for a long time. With age, the secondary dentin gradually generates and the volume of pulp cavity constantly decreases. Therefore, forensic dentists proposed that age-related changes of dentin-pulp complex could be used to estimate age, which has been widely applied in forensic practice over the years. Due to the development of imaging technology, a variety of methods have been advocated by forensic dentists to detect the age-related changes of dentin-pulp complex for age estimation. However, different methods have their own advantages and limitations, forensic scientists should combine the use of different methods for improving the accuracy of age estimation according to the actual situation. This paper reviews current research of age estimation based on dentin-pulp complex, so as to provide reference for related research.
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Humans , Age Determination by Teeth , Dental Pulp , Dentin , Forensic Dentistry/methodsABSTRACT
Objective:To explore the effect of low intensity pulsed ultrasound (LIPUS) on TGF-β1/Smad 2,3 signal pathway during the dentin injury and repair.Methods:Among 25 Sprague-Dawley rats,5 rats served as a blank control group without treatment.The remaining 20 rats received modified caries preparation inbilateral maxillary first molars to establish a model of dentin-pulp injury and repair.The right maxillary first molars served as a LIPUS group,which received LIPUS irradiation (frequency:1.5 MHz,pulse width:200 μs,pulse repetition frequency:1 kHz,spatial averaged temporal averaged intensity:30 mW/cm2,20 min/d),and the left maxillary first molars served as a cavity-prepared group,which received fake LIPUS irradiation.The rats were sacrificed at 1,3,5,7 and 14 days after LIPUS irradiation.Immunohistochemical staining and Image-pro plus 6.0 were applied to detect the expression and distribution of transforming growth factor-beta1 (TGF-β1) and small mothers against decapentaplegic 2/3(Smad 2 and Smad 3).Results:Immunohistochemical staining showed that the expression of TGF-β1 and Smad 2,3were low innormal pulp,but they were increased in different degree after dentin injury.The result of image analysis showed that the expression of TGF-β1 in the cavity-prepared group gradually increased at the first day and peaked at day 5,and then it returned to normal level at day 14.However,the expression of TGF-β 1 in the LIPUS group were significantly higher than that in the cavity-prepared group at day 3 and 5 (bothP＜0.05).The expressions of Smad 2,3 in both the LIPUS group and the cavity-prepared group were consistently increased all the way, but the expressions in the LIPUS group were higher compared with that in the cavity-prepared group (P＜0.05).Conclusion:The TGF-β1/Smad 2,3 signal pathway can be activated during the dentin injury and repair.LIPUS can up-regulate the expression of TGF-β1 and Smad 2,3 in the early period,which may take part in the dentin-pulp complex injury and repair process.
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A engenharia de tecido pulpar tem como objetivo substituir a polpa dentária inflamada ou necrosada por um tecido saudável e funcional, capaz de formar nova dentina para reparar a estrutura dentária perdida. Assim, os objetivos deste trabalho foram: avaliar a habilidade de diferenciação de células tronco de dentes decíduos exfoliados humanos (SHED) em odontoblastos funcionais, demonstrando a formação de tecido mineralizado in vivo; e estudar o efeito de VEGF em SHED com relação à estimulação de vias de sinalização celular (STAT3, AKT e ERK), proliferação, migração, formação de estruturas tubulares e diferenciação em células endoteliais. O início do processo de mineralização de SHED tratadas com dexametasona, ácido ascórbico 'beta' - glicerofosfato pôde ser detectado por meio da produção da enzima fosfatase alcalina a partir da segunda semana de cultura, mas a expressão de RNAm para DSPP só foi observada após 28 dias de indução. Utilizando-se o modelo de fatias de dentes e matrizes condutivas implantadas no dorso de camundongos imunodeprimidos, demonstrou-se a diferenciação de SHED em células semelhantes a odontoblastos, as quais tiveram imunomarcação positiva com o anticorpo DMP-1. A deposição de dentina, seguindo um ritmo centrípeto de crescimento, numa taxa de 14,1 µm por dia também foi demonstrada por meio da marcação com tetraciclina. O tratamento das SHED com VEGF estimulou a fosforilação de ERK e AKT e a diminuiu a fosforilação de STAT3 em um período de uma hora, provavelmente por meio de sua ligação com os receptores VEGFR-1 e NP-1 presentes nestas células. Além disso, VEGF intensificou a organização das SHED em estruturas tubulares, havendo diferença estatisticamente significativa entre os grupos tratado e não tratado a partir do 5o dia de tratamento. Entretanto, VEGF não estimulou a proliferação nem a migração destas células. Os resultados de RT-PCR mostraram que SHED cultivadas em fatias de dentes e ...
Dental pulp tissue engineering aims to replace the inflamed or necrotic pulp by a healthy and functionally competent tissue able to form new dentin in order to repair lost structure. The purposes of this work were: to evaluate the differentiation ability of stem cells from human exfoliated deciduous teeth (SHED) into functional odontoblasts, showing the formation of mineralized tissue in vivo; and to study the effect of VEGF on SHED with regards to the stimulation of cell signaling pathways (STAT3, AKT and ERK), the proliferation, migration, capillary sprouting, and the differentiation into endothelial cells. The beginning of the mineralization process of SHED treated with dexamethasone, ascorbic acid and beta-glycerophosphate could be detected through the production of alkaline phosphatase after the second week of culture, but the expression of DSPP mRNA was only observed after 28 days of induction. Using the tooth slice and scaffold model implanted in the dorsum of immunocompromised mice, the differentiation of SHED into odontoblast-like cells, which were immunostained with DMP-1 antibody, was demonstrated. Dentin deposition following a centripetal rhythm, in a rate of 14.1 µm per day, was also shown through the tetracycline labeling. VEGF treatment of SHED stimulated the ERK and AKT phosphorilation, and decreased the phosphorilation of STAT3 over 1 hour period, presumably due to its binding to VEGFR-1 and NP-1 receptors in these cells. In addition, VEGF enhanced SHED organization into tubular structures, with statistically significant difference between the treated group and the non-treated one after the 5th day of treatment. However, VEGF did not stimulate proliferation and migration of these cells. RT-PCR results demonstrated that SHED seeded in the tooth slices and scaffolds expressed VEGFR-2 after the first day of VEGF stimulation...
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Adolescent , Adult , Cell Differentiation , Tooth, Deciduous/cytology , Endothelial Cells , Odontoblasts , Stem Cells , Tooth Exfoliation , Blood Vessels , Dentinogenesis , Vascular Endothelial Growth FactorsABSTRACT
Objective To evaluate the odontogenetic ability of first branchial arch cells of E12.5 rats. Methods First branchial arch cells (mandibular process) of E12.5 SD rats were isolated enzymatically and collected. After combined with gelatin sponge, the cells were transplanted into the renal capsule of a rat. The specimen was taken out and evaluated by histological and immunohistochemical methods in 4 weeks after growth in renal capsule. Results The first branchial arch cells with gelatin sponge developed dentin-pulp complex-like structure. Dentin sialoprotein (DSP) was expressed in the newly formed dentin-like structure. The green mineralized matrix was further identified with Masson’s trichrome staining. Conclusion Cells from first branchial arch of E12.5 rats can partially keep genetic signal of tooth growth and form dentin-pulp complex-like structure in renal capsule.