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@#As a highly conserved signal pathway in evolution, the WNT signaling pathway plays an essential role in periodontium growth, development and injury repair. The Axin-associated protein Axin2 is a direct effector molecule of the WNT signaling pathway and labels WNT-responsive cells well. Studies have shown that Axin2-positive (Axin2+) cells in the periodontium have the potential for self-renewal, replication and multidirectional differentiation. This article reviews the temporal and spatial distribution of Axin2+ cells in periodontal tissue development and the role and regulatory mechanism of Axin2+ cells in periodontal tissue development, regeneration and tissue remodeling to provide new ideas for periodontal tissue regeneration. The literature review showed that Axin2+ cells were the main cell source of periodontium development, and Axin2+ cells played essential roles in tooth extraction socket healing, implant osseointegration, periodontal tissue remodeling and junctional epithelium regeneration. The function of Axin2+ cells was positively regulated by the canonical WNT signaling pathway. However, the regulatory mechanisms of other signaling pathways on Axin2+ cells remain to be elucidated.
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The mobility of teeth in terms of periotestometry and hydration of periodontal tissues in terms of bioimpedance spectrometry were studied in healthy volunteers without dental and concomitant somatic diseases. It was found that teeth of these subjects have both low and pathological mobility. It was also revealed as increased hydration (edema), indicating the presence of inflammation, and reduced hydration, indicating atrophic processes in periodontal tissues. A comparison of the data of periotestometry and bioimpedance spectrometry showed that the indicators of mobility of the teeth and hydration of the periodontal tissues reflect different characteristics of the functional state of dentoalveolar system, and can be used as complementary in the diagnostic studies.
Subject(s)
Periodontal Diseases/diagnosis , Spectrum Analysis , Tooth Mobility/diagnosis , Periodontium/anatomy & histology , Organism Hydration StatusABSTRACT
Background Root conditioning agents reveal the orifices of dentinal tubules and the dentin collagen matrix and provide a substrate which plays a role chemotaxis migration and proliferation of cells involved in periodontal healing and formation of new connective tissue attachment. Materials and methods A total of 15 extracted teeth which were periodontally involved were utilised for the study. All the teeth received 25% citric acid application. The samples were subjected to scanning electron microscope evaluation. The photomicrographs were analysed by image software analyser to assess its surface area. Results Group II showed better results for mean surface area. Conclusion: These results show that citric acid could be a better healing biomaterial in periodontal regeneration by increasing surface area.
ABSTRACT
Introducción: La implementación de modelos animales para el estudio de los tejidos dentales y periodontales de dientes articulados en sus alvéolos sometidos a altas temperaturas permite el establecimiento de parámetros repetitivos que contribuyen con los procesos de identificación. Objetivo: Describir los cambios radiográficos de los tejidos dentales y periodontales de cerdo (Sus domesticus) sometidos a altas temperaturas. Material y métodos: Se realizó un estudio observacional descriptivo de naturaleza pseudo-experimental in vitro para observar los cambios radiográficos de los tejidos dentales y periodontales en 60 dientes de cerdo doméstico sometidos a altas temperaturas (200, 400, 600, 800 y 1,000 ºC). Resultados: Los tejidos dentales y periodontales estudiados presentan gran resistencia a las altas temperaturas sin variar considerablemente su microestructura, de tal manera que los cambios físicos (estabilidad dimensional, fisuras, grietas y fracturas) que ocurren en la medida que aumenta la temperatura pueden describirse a través de radiografía convencional. Conclusiones: El análisis radiográfico de los dientes articulados en sus respectivos alvéolos se constituye en un mecanismo para determinar la temperatura a la cual estuvo sometido un diente, lo que puede ser empleado durante el proceso de identificación odontológica y documentación de la necropsia médico-legal para el caso de cadáveres o restos humanos quemados, carbonizados e incinerados. El cerdo doméstico (Sus domesticus) se constituye en un modelo animal experimental adecuado para estudiar dichos cambios; sin embargo, se recomienda realizar un estudio en dientes humanos articulados en su respectiva unidad alveolar, para determinar si los hallazgos radiográficos descritos se repiten y son extrapolables.
Introduction: The implementation of animal models for the study of periodontal and dental tissues of teeth articulated into their sockets and subjected to high temperatures allows the establishment of repetitive parameters which might contribute to identification processes. Aim: To describe radiographic changes of pig's (Sus domesticus) periodontal and dental tissues subjected to high temperatures. Material and methods: An in vitro pseudo-experimental, descriptive and observational study was undertaken in order to assess radiological changes of periodontal and dental tissues of 60 domestic pig's teeth which had been subjected to high temperatures (200, 400, 600, 800 and 1,000 ºC). Results: The dental and periodontal tissues subject of this research article presented strong resistance to high temperatures without considerable variation of their micro-structure. Thus, physical changes (dimensional stability, fissures, cracks and fractures) which took place as temperature increased, could be described using a conventional X-ray. Conclusions: Radiographic examination of teeth articulated in their sockets can be established as a mechanism to determine the temperature at which the tooth was subjected. This could be used in processes of dental identification and medical-legal autopsy documentation in cases of burned, carbonized or incinerated human remains. Domestic pigs (Sus domesticus) can be regarded as a suitable experimental animal models to study the aforementioned changes. Nevertheless, a study involving human teeth articulated in their own socket is recommended in order to determine whether the radiographic findings herein described are replicated and can be extrapolated.
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BACKGROUND:With the development of researches on periodontal disease etiology and neuroendocrine factors, the role of neuroendocrine factors on the pathogenesis of periodontal disease and tissue restoration has become a hot spot. OBJECTIVE:To summarize the biological effect of neuropeptides on periodontal tissues and the changes of periodontal tissue after nerve injury. METHODS:A computer-based search of articles was performed in CNKI, Wanfang and PubMed databases using the key words ofneuropeptides, calcitonin gene related peptide, substance P, vasoactive intestinal peptide, neuropeptide Y and periodontal tissuein Chinese and English. The included articles focused on the effect of various neuropeptides on periodontal tissue. RESULTS AND CONCLUSION:Calcitonin gene related peptide, substance P, vasoactive intestinal peptide, and neuropeptide Y positive nerve fibers are widely distributed in periodontal support tissues. When sensory nerves are damaged, the target cel s in periodontal tissues are influenced due to changes of nerve fibers distribution and neuropeptide release. They also play a role in the reconstruction of alveolar bone, immune function of periodontal ligament and periodontal tissue. This evidence shows that neuroendocrine factors are closely linked with periodontal tissue. However, these studies concentrated in the animal models for orthodontic and fracture, the effect of the neurotransmitters such as neuropeptides on periodontal disease and the mechanisms need further exploration.
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Diabetes y enfermedad periodontal corresponden probablemente al mejor ejemplo de cómo una enfermedad sistémica puede tener un efecto en el territorio periodontal. Si bien esta asociación ha sido extensamente estudiada, muchas de las asociaciones propuestas presentan contradicciones. En la presente revisión de la literatura se analizan los siguientes tópicos relevantes para la práctica clínica en periodoncia e implantología: i) Identificación de enfermedad periodontal severa y su capacidad para diagnosticar casos de diabetes; ii) Efectos de la diabetes sobre la enfermedad periodontal; iii) Efectos de la diabetes sobre la reparación periodontal y periimplantaria; iv) Efecto del tratamiento periodontal sobre el control metabólico de la diabetes.
Diabetes and periodontal disease correspond to conditions that probably exemplify how a systemic disease may have a strong impact in the periodontium. Although this association has been studied for several years, many of these studies still show contradictory results. The present review analyses the following questions relevant for the clinician in the fields of periodontology: i) Value of the diagnosis of severe periodontitis and its capacity to identify previously un-diagnosed cases of diabetes; ii) Effects of diabetes on periodontal disease; iii) Effects of diabetes on periodontal and peri-implant tissue repair and regeneration and; iv) Effect of periodontal therapy on the metabolic control of diabetes.
Subject(s)
Humans , Diabetes Complications , Periodontitis/complications , Diabetes Mellitus/diagnosis , Diabetes Mellitus/physiopathology , Diabetes Mellitus/therapy , Periodontitis/etiology , Periodontitis/physiopathology , Periodontitis/therapyABSTRACT
Runx2 and Osterix, the transcription factors for osteoblast differentiation, are known as fundamental factors to regulate the development of calcified tissues. However, the biological functions of these factors in the development of the periodontal tissues remain unclear. In this study, we investigated the distribution of Runx2 and Osterix during periodontal tissue development of the mice. Mandibles from 14-day-old mice were prepared for paraffin section. Serial sections of the mandible containing 1st molar tooth germs were obtained as a thickness of 7 microm. Some sections were stained with hematoxylin and eosin. Others were used for immunohistochemistry for PCNA, Runx2, and Osterix. Epithelial cells in growing end of Hertwig's epithelial root sheath (HERS) and mesenchymal cells adjacent to the growing end of HERS expressed PCNA. Undifferentiated mesenchymal cells and hard tissue forming cells like cementoblasts and osteoblasts in early stage of differentiation expressed Runx2. Fully differentiated cementoblasts and osteoblasts secreting matrix proteins expressed Osterix. However, the cells terminated the matrix formation did not express Osterix. Periodontal ligament cells expressed Runx2 and Osterix. Pulp cells expressed Runx2 only.These results suggest that Runx2 and Osterix might regulate the differentiation of cementoblasts in the same manner as osteoblasts. Runx2 might participate in the process of cementoblast differentiation in early stage, whether Osterix might regulate the maturation and matrix synthesis of the cells.
Subject(s)
Animals , Mice , Dental Cementum , Eosine Yellowish-(YS) , Epithelial Cells , Hematoxylin , Immunohistochemistry , Mandible , Molar , Osteoblasts , Paraffin , Periodontal Ligament , Proliferating Cell Nuclear Antigen , Proteins , Tooth Germ , Transcription FactorsABSTRACT
Objective To evaluate the feasibility of reconstructing horizontal periodontal bone defects by tissue engineering based on bone marrow stromal cells(BMSCs)as seed cells and enamel matrix proteins(EMPs)as growth factors. Methods Two healthy rhesus monkeys were selected, and BMSCs were isolated from iliac marrow and serial subcultivation was conducted. The cells of induced BMSCs at passage 3 were harvested and mixed with Bio-oss collagen. The models of horizontal periodontal bone defects were established surgically in each buccal side of the posterior teeth, and were divided into four groups (blank control group, material group, cells/material group and cells/material/EMPs group). The histological and Micro-CT observation were carried out 8 weeks later. Results In the blank control group, the defects were filled with fibrous connective tissue. There was newly-formed alveolar bone in the material group. In the cells/material group, periodontal regeneration could be observed, while the newly-formed cementum was irregular and less in quantity. In the cells/material/EMPs group, the amount of newly-formed alveolar bone was larger, and the newly-formed cementum was continuous and regular. Conclusion The tissue engineering technique of BMSCs as seed cells in combination with EMPs induction can significantly promote the regeneration of periodontal tissue.