Semaphorin 4D Induces Vasculogenic Differentiation of Dental Pulp Stem Cells.

This work aimed to evaluate the effect of Semaphorin 4D (SEMA4D) signaling through Plexin B1 on the vasculogenic differentiation of dental pulp stem cells. We assessed the protein expression of SEMA4D and Plexin B1 in dental pulp stem cells (DPSC) from permanent human teeth and stem cells from human exfoliated deciduous (SHED) teeth using Western blots. Their expression in human dental pulp tissues and DPSC-engineered dental pulps was determined using immunofluorescence. We then exposed dental pulp stem cells to recombinant human SEMA4D (rhSEMA4D), evaluated the expression of endothelial cell differentiation markers, and assessed the vasculogenic potential of rhSEMA4D using an in vitro sprouting assay. Lastly, Plexin B1 was silenced to ascertain its role in SEMA4D-mediated vasculogenic differentiation. We found that SEMA4D and Plexin B1 are expressed in DPSC, SHED, and human dental pulp tissues. rhSEMA4D (25-100 ng/mL) induced the expression of endothelial markers, i.e., vascular endothelial growth factor receptor (VEGFR)-2, cluster of differentiation (CD)-31, and tyrosine kinase with immunoglobulin-like and EGF-like domains (Tie)-2, in dental pulp stem cells and promoted capillary-like sprouting in vitro (p < 0.05). Furthermore, Plexin B1 silencing abrogated the vasculogenic differentiation of dental pulp stem cells and significantly inhibited capillary sprouting upon exposure to rhSEMA4D. Collectively, these data provide evidence that SEMA4D induces vasculogenic differentiation of dental pulp stem cells through Plexin B1 signaling.

Stem cells: therapeutic potential in dentistry.

AIM: The aim of this paper is to present a review and discussion of the current status of stem cell research with regard to tooth generation. BACKGROUND: Stem cells have been isolated from the pulp tissue of both deciduous and permanent teeth as well as from the periodontal ligament. Dental pulp stem cells demonstrate the capacity to form a dentin pulp-like complex in immunocompromised mice. A tooth-like structure was successfully formed, using a heterogeneous mixture of dental enamel epithelium, pulp mesenchymal cells, and scaffolds. CONCLUSION: The scientific community understands the need for more investigations to completely understand the conditions that would best favor the creation of a tooth substitute. Recent gains in the understanding of the molecular regulation of tooth morphogenesis, stem cell biology, and biotechnology offers the opportunity to realize this goal. CLINICAL SIGNIFICANCE: These findings, combined with the recent progress in stem cell research and tissue engineering, might allow the development of alternatives for current materials and therapies used to treat tooth tissue loss (e.g., enamel, dentin, pulp), reconstruct dentoalveolar and craniofacial bone defects, and eventually replace an entire tooth.

Clinical outcomes and prognostic factors of head and neck squamous cell carcinoma: a ten-year follow-up study

Abstract Traditional guidelines for determining the prognosis of patients with head and neck squamous cell carcinoma (HNSCC) are used to make therapeutic decisions. However, only 50% of the patients had lived for more than five years. The present study aimed to analyze the correlation of traditional prognostic factors such as tumor size, histological grading, regional metastases, and treatment with the survival of patients with HNSCC. A total of 78 patients diagnosed with HNSCC were followed up for 10 years after diagnosis and treatment. The health status of the patients was tracked at four time points, and according to the evolution of the patients and their final clinical status, we performed a prognostic analysis based on the clinical outcomes observed during the follow-up period. The final study cohort comprised 50 patients. Most patients had tumors < 4 cm in size (64%) and no regional metastases (64%); no patients had distant metastases at the time of diagnosis. Most individuals had tumors with good (48%) and moderate (46%) degrees of malignancy. At the end of the follow-up period, only 14% of the patients were discharged, 42% died of the tumor, and 44% remained under observation owing to the presence of a potentially malignant disorder, relapse, or metastases. This analysis showed that traditional prognostic factors were not accurate in detecting subclinical changes or predicting the clinical evolution of patients.

Vascular endothelial growth factor and its relationship with the dental pulp.

The dental pulp is a loose connective tissue located within rigid dentinal walls. Therefore, when subjected to a stimulus, the pulpal tissue has little expansion capacity. The defense mechanisms of this tissue include the formation of tertiary dentin as well as the production of signaling molecules that help in the repair. The dentin matrix is rich in growth factors (GFs) that, when diluted and diffused into the pulp tissue, aid the healing process of the dentinopulpar complex. The angiogenic GFs participate in this event. Vascular endothelial growth factor (VEGF), a potent mitogen for endothelial cells, promotes endothelial cell survival and angiogenesis. Among its receptors, VEGFR-2 seems to be the most intimately associated with mitogenic activities, cell migration, vascular permeability, and survival of endothelial cells. This literature review addresses the cell-signaling process that occurs in response to a pulp stimulus up to its transduction in the target cell, describing the VEGF, as well as its characteristics and receptors. The reported studies have correlated the expression of VEGF and its potential functions that may have an impact on several dental specialties, thus indicating that further clinical investigations should be conducted in order to translate the results obtained until this moment primarily in laboratory experiments.

Immunohistochemical Expression of TGF-ß1 and Osteonectin in engineered and Ca(OH)2-repaired human pulp tissues.

The aim of the present study was to evaluate the expression of transforming growth factor-ß1 (TGF-ß1) and osteonectin (ON) in pulp-like tissues developed by tissue engineering and to compare it with the expression of these proteins in pulps treated with Ca(OH)2 therapy. Tooth slices were obtained from non-carious human third molars under sterile procedures. The residual periodontal and pulp soft tissues were removed. Empty pulp spaces of the tooth slice were filled with sodium chloride particles (250-425 µm). PLLA solubilized in 5% chloroform was applied over the salt particles. The tooth slice/scaffold (TS/S) set was stored overnight and then rinsed thoroughly to wash out the salt. Scaffolds were previously sterilized with ethanol (100-70°) and washed with phosphate-buffered saline (PBS). TS/S was treated with 10% EDTA and seeded with dental pulp stem cells (DPSC). Then, TS/S was implanted into the dorsum of immunodeficient mice for 28 days. Human third molars previously treated with Ca(OH)2 for 90 days were also evaluated. Samples were prepared and submitted to histological and immunohistochemical (with anti-TGF-ß1, 1:100 and anti-ON, 1:350) analyses. After 28 days, TS/S showed morphological characteristics similar to those observed in dental pulp treated with Ca(OH)2. Ca(OH)2-treated pulps showed the usual repaired pulp characteristics. In TS/S, newly formed tissues and pre-dentin was colored, which elucidated the expression of TGF-ß1 and ON. Immunohistochemistry staining of Ca(OH)2-treated pulps showed the same expression patterns. The extracellular matrix displayed a fibrillar pattern under both conditions. Regenerative events in the pulp seem to follow a similar pattern of TGF-ß1 and ON expression as the repair processes.

Influence of poly-L-lactic acid scaffold's pore size on the proliferation and differentiation of dental pulp stem cells.

The aim of this study was to evaluate the influence of the poly-L-lactic acid (PLLA)-based scaffold's pore size on the proliferation and differentiation of dental pulp stem cells (DPSCs). The scaffolds were prepared in pulp chambers of 1-mm-thick tooth slices from third molars using salt crystals (150-250 µm or 251-450 µm) as porogen. DPSC (1x105 cells) were seeded in the scaffolds with different pore sizes, and cultured in 24-well plates. The cell proliferation was evaluated using the WST-1 assay after 3-21 days. Furthermore, RT-PCR was used to assess the differentiation of the DPSCs into odontoblasts, using markers of odontoblastic differentiation (DSPP, DSP-1 and MEPE). RNA from human odontoblasts was used as control. Cell proliferation rate was similar in both scaffolds except at the 14th day period, in which the cells seeded in the scaffolds with larger pores showed higher proliferation (p<0.05). After 21 days DPSCs seeded in both evaluated scaffolds were able of expressing odontoblastic markers DMP-1, DSPP and MEPE. In summary, both scaffolds tested in this study allowed the proliferation and differentiation of DPSCs into odontoblast-like cells.

Tissue engineering: from research to dental clinics.

UNLABELLED: Tissue engineering is an interdisciplinary field that combines the principles of engineering, material and biological sciences toward the development of therapeutic strategies and biological substitutes that restore, maintain, replace or improve biological functions. The association of biomaterials, stem cells, growth and differentiation factors has yielded the development of new treatment opportunities in most of the biomedical areas, including Dentistry. The objective of this paper is to present the principles underlying tissue engineering and the current scenario, the challenges and the perspectives of this area in Dentistry. SIGNIFICANCE: The growth of tissue engineering as a research field has provided a novel set of therapeutic strategies for biomedical applications. Indeed, tissue engineering may lead to new strategies for the clinical management of patients with dental and craniofacial needs in the future.

Nano-/microfiber scaffold for tissue engineering: physical and biological properties.

Alginate hydrogel (AH) has intrinsic physical and biological limitations that hinder its broader application in tissue engineering. We hypothesized that the inclusion of nanofibers in the hydrogel and the use of a biotemplate that mimics nature would enhance the translational potential of alginate hydrogels. In this study, we have shown a method to obtain nano-/microfibers of titanium (nfTD) and hydroxyapatite (nfHY) using cotton as a biotemplate. These fibers were incorporated in the alginate hydrogel and the mechanical characteristics and biological response to these reinforced materials were evaluated. We observed that these nanofibers resembled the structure of natural collagen and did not mediate cell toxicity. The incorporation of nfTD or nfHY to the AH has not increased the viscosity of the hydrogel. Therefore, this is a feasible method to produce a scaffold with improved physical characteristics, while at the same time generating an enhanced environment for cell adhesion and proliferation.

Dental pulp tissue engineering.

Dental pulp is a highly specialized mesenchymal tissue that has a limited regeneration capacity due to anatomical arrangement and post-mitotic nature of odontoblastic cells. Entire pulp amputation followed by pulp space disinfection and filling with an artificial material cause loss of a significant amount of dentin leaving as life-lasting sequelae a non-vital and weakened tooth. However, regenerative endodontics is an emerging field of modern tissue engineering that has demonstrated promising results using stem cells associated with scaffolds and responsive molecules. Thereby, this article reviews the most recent endeavors to regenerate pulp tissue based on tissue engineering principles and provides insightful information to readers about the different aspects involved in tissue engineering. Here, we speculate that the search for the ideal combination of cells, scaffolds, and morphogenic factors for dental pulp tissue engineering may be extended over future years and result in significant advances in other areas of dental and craniofacial research. The findings collected in this literature review show that we are now at a stage in which engineering a complex tissue, such as the dental pulp, is no longer an unachievable goal and the next decade will certainly be an exciting time for dental and craniofacial research.

Pulp tissue from primary teeth: new source of stem cells.

SHED (stem cells from human exfoliated deciduous teeth) represent a population of postnatal stem cells capable of extensive proliferation and multipotential differentiation. Primary teeth may be an ideal source of postnatal stem cells to regenerate tooth structures and bone, and possibly to treat neural tissue injury or degenerative diseases. SHED are highly proliferative cells derived from an accessible tissue source, and therefore hold potential for providing enough cells for clinical applications. In this review, we describe the current knowledge about dental pulp stem cells and discuss tissue engineering approaches that use SHED to replace irreversibly inflamed or necrotic pulps with a healthy and functionally competent tissue that is capable of forming new dentin.

Immunohistochemical expression of TGF-ß1 and osteonectin in engineered and Ca(OH)2-repaired human pulp tissues

Abstract The aim of the present study was to evaluate the expression of transforming growth factor-β1 (TGF-β1) and osteonectin (ON) in pulp-like tissues developed by tissue engineering and to compare it with the expression of these proteins in pulps treated with Ca(OH)2 therapy. Tooth slices were obtained from non-carious human third molars under sterile procedures. The residual periodontal and pulp soft tissues were removed. Empty pulp spaces of the tooth slice were filled with sodium chloride particles (250-425 µm). PLLA solubilized in 5% chloroform was applied over the salt particles. The tooth slice/scaffold (TS/S) set was stored overnight and then rinsed thoroughly to wash out the salt. Scaffolds were previously sterilized with ethanol (100-70°) and washed with phosphate-buffered saline (PBS). TS/S was treated with 10% EDTA and seeded with dental pulp stem cells (DPSC). Then, TS/S was implanted into the dorsum of immunodeficient mice for 28 days. Human third molars previously treated with Ca(OH)2 for 90 days were also evaluated. Samples were prepared and submitted to histological and immunohistochemical (with anti-TGF-β1, 1:100 and anti-ON, 1:350) analyses. After 28 days, TS/S showed morphological characteristics similar to those observed in dental pulp treated with Ca(OH)2. Ca(OH)2-treated pulps showed the usual repaired pulp characteristics. In TS/S, newly formed tissues and pre-dentin was colored, which elucidated the expression of TGF-β1 and ON. Immunohistochemistry staining of Ca(OH)2-treated pulps showed the same expression patterns. The extracellular matrix displayed a fibrillar pattern under both conditions. Regenerative events in the pulp seem to follow a similar pattern of TGF-β1 and ON expression as the repair processes.

Influence of Poly-L-Lactic Acid Scaffold's Pore Size on the Proliferation and Differentiation of Dental Pulp Stem Cells

The aim of this study was to evaluate the influence of the poly-L-lactic acid (PLLA)-based scaffold's pore size on the proliferation and differentiation of dental pulp stem cells (DPSCs). The scaffolds were prepared in pulp chambers of 1-mm-thick tooth slices from third molars using salt crystals (150-250 µm or 251-450 µm) as porogen. DPSC (1x105 cells) were seeded in the scaffolds with different pore sizes, and cultured in 24-well plates. The cell proliferation was evaluated using the WST-1 assay after 3-21 days. Furthermore, RT-PCR was used to assess the differentiation of the DPSCs into odontoblasts, using markers of odontoblastic differentiation (DSPP, DSP-1 and MEPE). RNA from human odontoblasts was used as control. Cell proliferation rate was similar in both scaffolds except at the 14th day period, in which the cells seeded in the scaffolds with larger pores showed higher proliferation (p<0.05). After 21 days DPSCs seeded in both evaluated scaffolds were able of expressing odontoblastic markers DMP-1, DSPP and MEPE. In summary, both scaffolds tested in this study allowed the proliferation and differentiation of DPSCs into odontoblast-like cells.

O objetivo desse estudo foi avaliar a influência do tamanho dos poros de um scaffold à base de poli ácido láctico (PLLA) sobre a proliferação e diferenciação de células tronco da polpa dental (dental pulp stem cells - DPSC). Os scaffolds foram preparados dentro da câmara pulpar de discos de terceiros molares (1 mm), utilizando sal como porógeno (150-250 µm ou 251-450 µm). DPSC (1x105 células) foram semeadas nos scaffolds com diferentes tamanhos de poros e cultivadas em placas de 24 poços. A proliferação celular foi avaliada utilizando WST-1 após 3-21 dias. Além disso, RT-PCR foi utilizado para avaliar a diferenciação odontoblástica das DPSC utilizando marcadores da diferenciação odontoblástica (DSPP, DMP-1 e MEPE). RNA obtido de odontoblastos humanos foi utilizado como controle. A taxa de proliferação celular foi semelhante nos dois scaffolds avaliados, exceto no 14° dia, no qual as células cultivadas nos scaffolds com os maiores poros apresentaram uma maior taxa de proliferação (p<0,05). Após 21 dias, as DSPC cultivadas em ambos scaffolds avaliados foram capazes de expressar os marcadores odontoblásticos DMP-1, DSPP e MEPE. Em resumo, ambos scaffolds avaliados nesse estudo permitiram a proliferação e diferenciação odontoblástica das DPSC. .

Pulp tissue from primary teeth: new source of stem cells

SHED (stem cells from human exfoliated deciduous teeth) represent a population of postnatal stem cells capable of extensive proliferation and multipotential differentiation. Primary teeth may be an ideal source of postnatal stem cells to regenerate tooth structures and bone, and possibly to treat neural tissue injury or degenerative diseases. SHED are highly proliferative cells derived from an accessible tissue source, and therefore hold potential for providing enough cells for clinical applications. In this review, we describe the current knowledge about dental pulp stem cells and discuss tissue engineering approaches that use SHED to replace irreversibly inflamed or necrotic pulps with a healthy and functionally competent tissue that is capable of forming new dentin.

Dental pulp tissue engineering

Dental pulp is a highly specialized mesenchymal tissue that has a limited regeneration capacity due to anatomical arrangement and post-mitotic nature of odontoblastic cells. Entire pulp amputation followed by pulp space disinfection and filling with an artificial material cause loss of a significant amount of dentin leaving as life-lasting sequelae a non-vital and weakened tooth. However, regenerative endodontics is an emerging field of modern tissue engineering that has demonstrated promising results using stem cells associated with scaffolds and responsive molecules. Thereby, this article reviews the most recent endeavors to regenerate pulp tissue based on tissue engineering principles and provides insightful information to readers about the different aspects involved in tissue engineering. Here, we speculate that the search for the ideal combination of cells, scaffolds, and morphogenic factors for dental pulp tissue engineering may be extended over future years and result in significant advances in other areas of dental and craniofacial research. The findings collected in this literature review show that we are now at a stage in which engineering a complex tissue, such as the dental pulp, is no longer an unachievable goal and the next decade will certainly be an exciting time for dental and craniofacial research.

A polpa dental é um tecido conjuntivo altamente especializado que possui uma restrita capacidade de regeneração, devido à sua disposição anatômica e à natureza pós-mitótica das células odontoblásticas. A remoção total da polpa, seguida da desinfecção do canal radicular e seu preenchimento com material artificial proporciona a perda de uma significante quantidade de dentina deixando como sequela um dente não vital e enfraquecido. Entretanto, a endodontia regenerativa é um campo emergente da engenharia tecidual, que demonstrou resultados promissores utilizando células-tronco associadas à scaffolds e moléculas bioativas. Desta forma, esse artigo revisa os recentes avanços obtidos na regeneração do tecido pulpar baseado nos princípios da engenharia tecidual e fornece aos leitores informações compreensivas sobre os diferentes aspectos envolvidos na engenharia tecidual. Assim, nós especulamos que a combinação ideal de células, scaffolds e moléculas bioativas pode resultar em significantes avanços em outras áreas da pesquisa odontológica. Os dados levantados em nossa revisão demonstraram que estamos em um estágio no qual, o desenvolvimento de tecidos complexos, tais como a polpa dental, não é mais inatingível e que a próxima década será um período extremamente interessante para a pesquisa odontológica.

Interferência oclusal artificialmente provocada e dor / Occlusal interference artificially caused and pain

Vinte pacientes foram passíveis de colocação, em seus primeiros molares inferiores esquerdos, de uma quantidade em excesso de material selante usualmente utilizado em Odontopediatria, criando uma interferência oclusal a fechamento em posição intercuspal (máxima intercuspidação). Durante dez (10) dias os pacientes foram observados quanto ao eventual parecimento de sintomatologia, a qual, quando presente foi registrada em ficha especial com uma gradação de intensidade de 1 a 10. Os resultados mostraram a ocorrência de uma sintomatologia dolorosa bastante elevada nos primeiros dias, alterando-se com o decorrer do tempo de observação. Os resultados obtidos parecem confirmar achados anteriores que mostram que a aplicação de forças inusitadas sobre os dentes ou sua provocação, influenciam o nível de secreções psicoendócrinas, bem como mobilizam trajetórias neuropeptidérgicas na polpa humana, e determinam sintomatologia dolorosa variável em intensidade, duração e localização, no sistema estomatognático

Capacidade máxima de abertura bucal em crianças de 3 a 12 anos de idade / Maximum opening mouth capacity among children aged 3-12 years

Cinqüenta e seis pacientes foram examinados na Clínica de Odontopediatria da Faculdade de Odontologia da UFRGS com a finalidade de determinar um limite normal de sua capacidade máxima de abertura bucal. Eles foram divididos em três grupos de idade, 3 a 5, 6 a 8, e 9 a 12 anos. O método utilizado é bastante simples e pode ser realizado em um curto espaço de tempo. Os resultados obtidos indicam que o método pode ser incluído em um exame de rotina e em Odontopediatria e pode servir como um alerta no que se refere a desordens do sistema estomatognático em crianças

Bruxismo em crianças / Bruxism in children

O presente trabalho se destinou a revisar a literatura pertinente aos ítens principais a respeito de: 1) Conceitos de bruxismo 2) Levantamentos epidemiológicos em crianças 3) Etiologia 4) Sinais e sintomas dos distúrbios funcionais de ATM e músculos mastigatórios 5) Exame e diagnóstico 5.1) Anamnese 5.2) Clínico 6) Das desordens de disfunçäo de ATM e músculos mastigatórios nas crianças