Research progress on cemental tears in terms of clinical diagnosis and treatment / 口腔疾病防治

@#A cemental tear is defined as an incomplete or complete detachment of the cementum along the dentino-cemental junction (CDJ) or the incremental line within the body of the cementum, which can also involve part of the root dentine adjacent to the cementum. The pathogenesis of cemental tears is not fully elucidated. From the literature review, possible predisposing factors were identified, including tooth type, sex, age, periodontitis, previous periodontal treatment or root canal treatment, history of dental trauma, and occlusal trauma or excessive occlusal force. The morphology of cemental tears can be either piece-shaped or U-shaped, which usually contributes to periodontal and periapical breakdown. Clinically, cemental tears have a unitary periodontal pocket and present with symptoms mimicking localized periodontitis, apical periodontitis, and vertical root fractures. Imaging examination is of great significance for the clinical diagnosis of cemental tears, which often manifest as thin ‘prickle-like’ radiopaque masses located longitudinally adjacent to the affected root surface. Exploratory surgery is needed in some cases. Although intraoperative cemental fragments and cemental lines on the root surface can assist in the diagnostic process, histopathology examination is the gold standard for the diagnosis of cemental tears. The treatment methods vary depending on the timing of the correct diagnosis and the clinical or radiological manifestations. With the development of regenerative biomaterials and the development of intentional replantation, an increasing number of affected teeth can survive for a long time. The aim of this review is to systematically describe the biological basis and predisposing factors, clinical features, radiographic and histological characteristics, diagnosis and clinical management of cemental tears, and treatment outcomes to help make a clear diagnosis and develop a personalized treatment plan.

Limitaciones Técnicas del Método de Conteo de Anulaciones del Cemento para Estimación de Edad. Hallazgos a Partir de Una Revisión con Búsqueda Sistemática / Technical Limitations of Cementum Annulation Count Method for age Estimation. Findings From A Scoping Review

En la última década, la odontología forense se ha enfocado en el desarrollo de metodologías para la estimación de edad (EE) debido a la gran demanda en procesos identificatorios. Entre esas técnicas, el conteo de anulaciones del cemento dental (TCA) ha ofrecido resultados promisorios, pero también contradictorios que han generado dudas sobre su precisión y confiabilidad. El objetivo de este trabajo fue caracterizar, establecer alcances, e identificar las limitaciones del conteo de TCA según los actuales estándares normativos y metodológicos. Se realizó una revisión con búsqueda sistemática del método de conteo de TCA para EE incluyendo estudios experimentales y notas técnicas en las bases PubMed/Medline, Scopus, Web of Science (WoS) y Embase. Se emplearon los términos "estimation", "age" y "cementum", con búsqueda manual complementaria en Google Scholar. Se excluyeron revisiones, estudios en colecciones arqueológicas, estudios radiológicos y cartas al editor. La búsqueda arrojó un total de 273 artículos, seleccionándose 27 que cumplieron con los criterios de inclusión. La mayoría de los estudios fueron publicados en Asia, particularmente en India (n=21). Sólo 6 artículos declararon el número total de individuos, tipos de diente y de cortes histológicos, siendo el premolar el más estudiado. Apenas dos artículos evaluaron la calidad de la muestra a analizar mediante legibilidad de los cortes obtenidos. El test más empleado para evaluar la precisión del método fue el coeficiente de correlación de Pearson (n=21). Estos hallazgos exponen la alta heterogeneidad reportada en las metodologías de EE mediante conteo por TCA, por lo que aún no existe un proceso estandarizado que abarque todas sus etapas y entregue resultados confiables siguiendo los estándares jurídicos actuales para la evidencia científica. Un mayor control de las limitaciones técnicas detectadas aumentará el valor como prueba en un contexto identificatorio legal o forense.

SUMMARY: In the last decade, forensic odontology has focused on the development of age estimation (AE) methodologies due to the great request in identification processes. Among these techniques, the tooth cementum annulation (TCA) count method has offered promising but also contradictory results, raising questions about its accuracy and reliability. The aim of this work was to characterize, establish the scope, and identify the limitations of the TCA count method according to the current normative and methodological standards. A scoping review was carried out for TCA count methods for AE, including experimental studies and technical notes in the PubMed/Medline, Scopus, Web of Science (WoS) and Embase databases. The terms "estimation", "age" and "cementum" were used, with a complementary manual search in Google Scholar. Reviews, studies in archaeological collections, radiological studies and letters to the editor were excluded. The search yielded a total of 273 articles, selecting 27 of them that met the inclusion criteria. Most of the studies were published in Asia, particularly India (n=21). Only 6 articles declared the total number of individuals, types of teeth, and histological sections, with the premolar being the most studied. Only two articles evaluated the quality of the sample to be analyzed through the legibility of the cuts obtained. The most widely used test to assess the precision of the method was the Pearson correlation coefficient (n=21). These findings expose the high heterogeneity reported in EE methodologies by counting TCA, so there is still no standardized process that covers in all its stages and delivers reliable results following current legal standards for scientific evidence. More control of the detected technical limitations will increase the value as evidence in a legal or forensic identification context.

Effect of recombinant human fibroblast growth factor 21 on the mineralization of cementoblasts and its related mechanism / 华西口腔医学杂志

OBJECTIVES@#To investigate the effect of recombinant human fibroblast growth factor 21 (rhFGF21) on the proliferation and mineralization of cementoblasts and its mechanism.@*METHODS@#Hematoxylin eosin, immunohistochemical staining, and immunofluorescence were used to detect the expression and distribution of fibroblast growth factor 21 (FGF21) in rat periodontal tissues and cementoblasts (OCCM-30), separately. Cell Counting Kit-8 was used to detect the proliferation of OCCM-30 under treatment with rhFGF21. Alkaline phosphatase staining and Alizarin Red staining were used to detect the mineralization state of OCCM-30 after 3 and 7 days of mineralization induction. The transcription and protein expression of the osteogenic-related genes Runx2 and Osterix were detected by real-time quantitative polymerase chain reaction (PCR) and Western blot analysis. The expression levels of genes of transforming growth factor β (TGFβ)/bone morphogenetic protein (BMP) signaling pathway in OCCM-30 were detected through PCR array analysis.@*RESULTS@#FGF21 was expressed in rat periodontal tissues and OCCM-30. Although rhFGF21 had no significant effect on the proliferation of OCCM-30, treatment with 50 ng/mL rhFGF21 could promote the mineralization of OCCM-30 cells after 7 days of mineralization induction. The transcriptional levels of Runx2 and Osterix increased significantly at 3 days of mineralization induction and decreased at 5 days of mineralization induction. Western blot analysis showed that the protein expression levels of Runx2 and Osterix increased during mineralization induction. rhFGF21 up-regulated Bmpr1b protein expression in cells.@*CONCLUSIONS@#rhFGF21 can promote the mineralization ability of OCCM-30. This effect is related to the activation of the TGFβ/BMP signaling pathway.

Glycogen synthase kinase 3 inhibition enhances mineral nodule formation by cementoblasts in vitro

Abstract This study aimed to investigate whether GSK-3 inhibition (CHIR99021) effectively promoted mineralization by cementoblasts (OCCM-30). OCCM-30 cells were used and treated with different concentrations of CHIR99021 (2.5, 5, and 10 mM). Experiments included proliferation and viability, cellular metabolic activity, gene expression, and mineral nodule formation by Xylene Orange at the experimental time points. In general, CHIR99021 did not significantly affect OCCM-30 viability and cell metabolism (MTT assay) (p > 0.05), but increased OCCM-30 proliferation at 2.5 mM on days 2 and 4 (p < 0.05). Data analysis further showed that inhibition of GSK-3 resulted in increased transcript levels of Axin2 in OCCM-30 cells starting as early as 4 h, and regulated the expression of key bone markers including alkaline phosphatase (Alp), runt-related transcription factor 2 (Runx-2), osteocalcin (Ocn), and osterix (Osx). In addition, CHIR99021 led to an enhanced mineral nodule formation in vitro under both osteogenic and non-osteogenic conditions as early as 5 days after treatment. Altogether, the results of the current study suggest that inhibition of GSK-3 has the potential to promote cementoblast differentiation leading to increased mineral deposition in vitro.

Caracteres Histológicos - Moleculares del Cemento Dental. La matriz no fibrilar y su rol en el origen, el mantenimiento y la regeneración tisular

El cemento es un tejido conjuntivo con la particularidad de que su matriz orgánica esta mineralizada. Dentro de sus componentes es posible identificar a las células donde podemos reconocer a los cementoblastos, los cementocitos y en ciertas condiciones los cementoclastos. En la matriz orgánica hay dos componentes, uno fibrilar representado principalmente por el colágeno tipo I, y otro no fibrilar el cual incluye moléculas diversas capaces de producir una variada cantidad de funciones. Al ser un conectivo mineralizado, la hidroxiapatita articula con la matriz orgánica para producir esta mineralización. El objetivo del presente trabajo es realizar una actualización de las características histológico - moleculares del cemento, y en especial de los componentes de matriz extracelular de tipo no fibrilar, y como estas aportan al mantenimiento y regeneración tisular.

O cemento é um tecido conjuntivo com a particularidade de sua matriz orgânica ser mineralizada. Dentro dos seus componentes encontramos as células onde podemos identificar os cementblastos, os cementócitos e em certas condições os cementclastos. Na matriz orgânica encontramos dois componentes, um fibrilar, representado principalmente pelo colágeno tipo I, e outro não fibrilar, que inclui diversas moléculas capazes de produzir um variado número de funções. Por ser um conjuntivo mineralizado, encontramos a hidroxiapatita que se articula com a matriz orgânica para produzir esta mineralização. O objetivo deste trabalho é atualizar as características histológico-moleculares do cimento, e principalmente dos componentes da matriz extracelular não fibrilar, e como estes contribuem para o manutenção e regeneração tecidual.

Cementum is a connective tissue with the particularity that its organic matrix is​​mineralized. Within its components it is possible to identify the cementoblasts, the cementocytes and in certain conditions the cementoclasts. In the organic matrix there are two components, one fibrillar, represented mainly by collagen type I, and another non-fibrillar, which includes diverse molecules capable of producing a varied number of functions. Being a mineralized connective, the hydroxyapatite articulates with the organic matrix to produce this mineralization. The objective of this work is to update the histological-molecular characteristics of cement, and especially the non-fibrillar extracellular matrix components, and how these contribute to maintenance and tissue regeneration.

Mesenchymal stem cells surpass the capacity of bone marrow aspirate concentrate for periodontal regeneration

Abstract Regenerative approaches using mesenchymal stem cells (MSCs) have been evaluated to promote the complete formation of all missing periodontal tissues, e.g., new cementum, bone, and functional periodontal ligaments. MSCs derived from bone marrow have been applied to bone and periodontal defects in several forms, including bone marrow aspirate concentrate (BMAC) and cultured and isolated bone marrow mesenchymal stem cells (BM-MSCs). This study aimed to evaluate the periodontal regeneration capacity of BMAC and cultured BM-MSCs in the wound healing of fenestration defects in rats. Methodology: BM-MSCs were obtained after bone marrow aspiration of the isogenic iliac crests of rats, followed by cultivation and isolation. Autogenous BMAC was collected and centrifuged immediately before surgery. In 36 rats, fenestration defects were created and treated with suspended BM-MSCs, BMAC or left to spontaneously heal (control) (N=6). Their regenerative potential was assessed by microcomputed tomography (µCT) and histomorphometry, as well as their cell phenotype and functionality by the Luminex assay at 15 and 30 postoperative days. Results: BMAC achieved higher bone volume in 30 days than spontaneous healing (p<0.0001) by enhancing osteoblastic lineage commitment maturation, with higher levels of osteopontin (p=0.0013). Defects filled with cultured BM-MSCs achieved higher mature bone formation in early stages than spontaneous healing and BMAC (p=0.0241 and p=0.0143, respectively). Moreover, significantly more cementum-like tissue formation (p<0.0001) was observed with new insertion of fibers in specimens treated with BM-MSCs within 30 days. Conclusion: Both forms of cell transport, BMAC and BM-MSCs, promoted bone formation. However, early bone formation and maturation were achieved when cultured BM-MSCs were used. Likewise, only cultured BM-MSCs were capable of achieving complete periodontal regeneration with inserted fibers in the new cementum-like tissue.

Research progress on basic fibroblast growth factor in promoting periodontal tissue regeneration / 口腔疾病防治

@#Basic fibroblast growth factor (bFGF) exhibits superior biological functions by improving periodontal inflammation, promoting the migration and proliferation of periodontal-related stem cells, promoting the formation of blood vessels and periodontal ligament-like tissue, and regulating the formation of bone/cementum. It plays an important role in tooth development, repair and regeneration. bFGF can be combined with seed cells and scaffold materials for periodontal tissue regeneration, which has been verified in a number of experimental studies. However, the application of bFGF alone as a drug in clinical treatment requires further research.

Using histological staining techniques to improve visualization and interpretability of tooth cementum annulation analysis / Uso de técnicas de tinción histológica para mejorar la visualización y la interpretación del análisis de la anulación del cemento dental

SUMMARY: The aim of the present study was to evaluate the effect of different staining techniques on applicability and accuracy of tooth cementum annulation (TCA) method. Nine decalcination techniques, 8 dehydration protocols and 8 different techniques were applied in 3 teeth from the persons of a known age. Black and white, and color images of histological sections were captured. An x- ray was taken of each tooth and they were photographed. Researchers were asked to observe both black/white and color images of histological sections. Researchers were divided into two groups. The first group analyzed histological images only, and the second group had photos of teeth and X-rays. In the first group of observers (without X ray) the differences in age estimation between real and observed age were significant for 2 younger patients, but not for the oldest patient, where the observed and real values matched. Of the 6 raters, the assesments of the last 3 (that used x-ray images together with histological sections) did not differ significantly from the real values. Extensive analysis and multiple repetitions performed in the present investigation revealed that the most optimal method of decalcification for TCA method was EDTA II for a period longer than 14 days at a section thickness of 2-3mm, while the most optimal protocol for dehydration was number IV. When it comes to staining, the most optimal staining protocol used for the cemental lines visualization and counting was Crocein Scarlet/Acid Fuchsin staining and Toluidine blue staining used at semithin section. Additional use of preexperimental evaluation employing x-ray of analyzed teeth decreased the errors of age estimation.

RESUMEN: El objetivo del presente estudio fue evaluar el efecto de diferentes técnicas de tinción sobre la aplicación y precisión del método de anulación de cemento dental (TCA). Se usaron nueve técnicas de descalcinación, 8 protocolos de deshidratación y 8 técnicas diferentes en 3 dientes de personas de edad conocida. Se capturaron imágenes en blanco y negro y en color de cortes histológicos. Se tomó una radiografía de cada diente y se fotografiaron. Los investigadores observaron las imágenes en blanco y negro y en color de las secciones histológicas. Los investigadores se dividieron en dos grupos; el primer grupo analizó solo imágenes histológicas y el segundo grupo tenía fotografías de los dientes y las radiografías. En el primer grupo de observadores (sin rayos X) las diferencias en la estimación de la edad entre la edad real y la edad observada fueron significativas para 2 pacientes más jóvenes, pero no para el paciente de mayor edad, donde los valores observados y reales coincidieron. De los 6 evaluadores, las valoraciones de los 3 últimos (que utilizaron imágenes de rayos X junto con cortes histológicos) no difirieron significativamente de los valores reales. El análisis exhaustivo y las múltiples repeticiones realizadas en la presente investigación revelaron que el método de descalcificación más óptimo para el método TCA fue EDTA II durante un período superior a 14 días con un grosor de sección de 2-3 mm, mientras que el protocolo óptimo para la deshidratación fue el número IV. En lo que respecta a la tinción, el protocolo de tinción más óptimo utilizado para la visualización y el recuento de las líneas de cemento fue la tinción con croceína escarlata / fucsina ácida y la tinción con azul de toluidina utilizada en la sección semifina. El uso adicional de la evaluación pre-experimental que emplea los rayos X de los dientes analizados disminuyó los errores de estimación de la edad.

Biomimetic restoration and regeneration of dentin and cementum / 口腔疾病防治

@#Dental hard tissues lack the ability to self-heal. In dentin and cementum, hydroxyapatite (HA) can exist outside and/or inside collagen fibers. It is difficult to repair or regenerate HA with a highly ordered orientation in the presence of collagen fibers. At present, the biomimetic mineralization of dentin and cementum, mainly carried out by imitating its biological formation process and its physiological structure, can be divided into those originating from the fiber mineralization mechanism and those with HA as the main component. The materials used include natural materials such as demineralized dentin matrix (DDM) and calcined bovine hydroxyapatite (BHA), and synthetic materials such as polymer-induced liquid precursor (PILP) and synthetic HA. In the future, natural materials and synthetic materials should be combined for the restoration and regeneration of dentin and cementum by means of biomimetic mineralization of calcium phosphate released by remineralization solution-HA.

Cemento-ossifying Fibroma of Mandible: A Case Report with Review of Literature

ABSTRACT Cemento-osseous dysplasia (COD) is a non-neoplastic process usually confined to the tooth-bearing areas of the jaws or edentulous alveolar processes. It is mostly seen in women during the third and fourth decades of life. The mandible is the most common location in 70% of cases in the premolar-molar region. This case report presents a case of cemento-ossifying fibroma with clinical features and radiographic features in a 23-year-old female patient.

Effects of cone beam computed tomography measurement of maxillary anterior teeth on implant success and patient satisfaction of maxillary anterior teeth / 中国基层医药

Objective:To investigate the effects of cone beam computed tomography measurement of maxillary anterior teeth on implant success and patient satisfaction of maxillary anterior teeth.Methods:120 patients who underwent maxillary anterior teeth implantation in Hangzhou Dental Hospital from October 2017 to October 2019 were included in this study. They were randomly assigned to receive either conventional maxillary anterior teeth implantation (control group, n = 60) or cone beam computed tomography measurement of maxillary anterior teeth and maxillary anterior teeth implantation (study group, n = 60). The implant success rate was compared between the two groups. Alveolar bone thickness and ISQ value immediately, 3 and 12 months after implantation as well as patient satisfaction were compared between the two groups. Results:Implant success rate in the observation group was significantly higher than that in the control group [96.67% (58/60) vs. 85.00% (51/60), χ2 = 4.904, P < 0.05]. In the observation group, alveolar bone thickness at 3 and 12 months after implantation was (1.53 ± 0.05) mm and (1.78 ± 0.12) mm, respectively, which was significantly higher than that in the control group [(1.46 ± 0.04) mm, (1.64 ± 0.10) mm, t = 9.839, 8.066, both P < 0.001]. In the observation group, ISQ value at 3 and 12 months after implantation was (76.83 ± 5.49) and (82.91 ± 4.85), respectively, which was significantly higher than that in the control group [(67.81 ± 4.61), (74.18 ± 5.21), t = 11.324, 11.038, both P < 0.001). Total satisfaction rate in the observation group was significantly higher than that in the control group [95.00% (57/60) vs. 81.67% (49/60), χ2 = 5.175, P < 0.05]. Conclusion:Cone beam computed tomography measurement of maxillary anterior teeth can help increase implant success rate and patient satisfaction.

Research progress on cell sheet technology and its application in periodontal tissue regeneration / 口腔疾病防治

@#At present, conventional periodontal treatment cannot achieve complete and effective periodontal tissue regeneration. Cell sheet technology (CST) is a kind of cell transplantation method without scaffold material that can maintain complete extracellular matrix, important ion channels of cells, growth factor receptors, etc., and ensure the interaction between cells and the extracellular matrix. In this paper, the application and research progress of the cell sheet in the field of periodontal tissue regeneration are reviewed. Different types of seed cells can be prepared into monolayer cell sheet, multilayer cell sheet, cell sheet fragments and cell sheet polymers. Among them, the monalayer cell sheet is easily damaged and requires high deoperator; the multilayer cell sheet shows improved mechanical properties, but its thickness needs to be controlled to avoid cell necrosis. The cell sheet fragment can be used in the narrow space between the alveolar bone and root cementum to reduce the difficulty of operation and improve the mechanical properties of the cell sheet. Cell sheet polymers are three-dimensional structures that can provide strong mechanical support and improve the stability of the cell sheet, but the stability of their biological activity needs to be further improved. In methods for construction of the cell sheet, the antifibrosis and antiangiogenesis properties of the amniotic sheet have shown that this structure is suitable as the matrix of cell culture; the method of using a temperature-sensitive culture dish is simple and easy; continuous induction with vitamin C can retain some important proteins on the cell surface; and the magnetic tissue engineering method can increase cell adhesion and easily form a stable cell sheet. The above methods have their own characteristics. In clinical applications, monolayer cell sheet is mainly used for direct transplantation to the receiving site to construct periodontal tissue; multilayer cell sheet of the same or different species overlap and are then transplanted to the receiving site; and multilayer cell sheet of the same kind are wrapped with scaffold material and then transplanted to the receiving site to construct a three-dimensional structure. Overall, cell sheet technology has shown good potential in periodontal tissue regeneration.

Displasia cemento-óssea florida: relato de dois casos tratados por diferentes abordagen / Florid cemento-osseous dysplasia: report of two cases treated with different approaches

Objetivo: relatar dois casos de displasia cemento-óssea florida, descrevendo a evolução clínico-radiográfica ao longo de 5 anos em um paciente assintomático e a abordagem cirúrgica em um caso sintomático. Relato de caso 1: paciente, melanoderma, sexo feminino, 56 anos de idade, encaminhada ao Serviço de Cirurgia Bucomaxilofacial da Universidade Federal da Bahia, por cirurgião-dentista clínico que notou alterações imagiológicas em radiografia panorâmica de rotina. Apesar da importante extensão da lesão em maxila e mandíbula, não havia qualquer sintoma ou sinal clínico de infecção. A paciente foi acompanhada durante 5 anos, com exames de imagem bianuais e medidas clínicas profiláticas. Relato de caso 2: paciente, melanoderma, sexo feminino, 57 anos, apresentou-se ao ambulatório de cirurgia queixando-se de atraso em cicatrização após remoção de um dente. A radiografia panorâmica e a tomografia computadorizada, em conjunto com dados clínicos, permitiram o diagnóstico de displasia cemento-óssea florida com infecção secundária. A paciente foi abordada por meio de osteotomia em região do defeito em mandíbula. A análise microscópica do espécime obtido confirmou a alteração displásica cementoide. Os sinais e sintomas regrediram e a paciente segue em acompanhamento. Considerações finais: a displasia cemento-óssea florida, portanto, é uma doença pouco frequente, cujas manifestações podem demandar diferentes abordagens. É importante o domínio clínico do cirurgião-dentista, uma vez que o diagnóstico equivocado pode guiar a escolhas terapêuticas com resultados insatisfatórios. (AU)

Objective: the objective of this article is to report two cases of florid cemento-osseous dysplasia describing the clinical-radiographic evolution over 5 years in an asymptomatic patient and the surgical approach in a symptomatic one. Case report 1: patient, melanoderma, female, 56 years old, referred to the service by a clinical Dentist who noticed imaging alterations in a routine panoramic radiography. Despite the important extension of the maxillary and mandibular lesion, there was no clinical sign or symptom of infection. The patient has been followed for 5 years with biannual imaging exams and prophylactic clinical measures. Case report 2: patient, melanoderma, female, 57 years old, presented to the surgery outpatient complaining of delay in healing after removal of a tooth. Panoramic X-ray and Computed Tomography together with clinical data allowed the diagnosis of florid cemento-osseous dysplasia with secondary infection. The patient was approached through osteotomy in the region of the mandible defect. The microscopic analysis of the specimen confirmed the dysplastic cementenoid alteration. Signs and symptoms regressed and the patient is in follow up. Final considerations: florida cementoosseous dysplasia is an infrequent disease, whose manifestations may require different approaches. The clinical domain of the Dentist is important, since misdiagnosis can lead to therapeutic choices with unsatisfactory results. (AU)

Application of biological factor in cementum regeneration / 中华口腔医学杂志

At the present day, curettage and periodontal surgery comprise the main strategy for the treatment of periodontitis, however, these methods are limited in regenerating cementum. It has been found that some biological factors such asenamel matrix derivative (EMD), transforming growth factor-β (TGF-β) and insulin-like growth factor (IGF) could promote cementum regeneration. In the cementum regenerationstudies, there has been a lack of criteria to distinguish cementum from alveolar bone and other types of cementum. Therefore, this article will briefly review the biological factors that affect the cementum regeneration and the molecular markers used to judge the regenerating cementum.

Isolation and characterization of a human cementocyte-like cell line, HCY-23

Abstract Cementum is the mineralized tissue covering the tooth root that functions in tooth attachment and post-eruptive adjustment of tooth position. It has been reported to be highly similar to bone in several respects but remains poorly understood in terms of development and regeneration. Here, we investigate whether cementocytes, the residing cells in cellular cementum, have the potential to be protagonist in cementum homeostasis, responding to endocrine signals and directing local cementum metabolism. Cells from healthy erupted human teeth were isolated using sequential collagenase/EDTA digestions, and maintained in standard cell culture conditions. A cementocyte-like cell line was cloned (HCY-23, for human cementocyte clone 23), which presented a cementocyte compatible gene expression signature, including the expression of dentin matrix protein 1 ( DMP1 ), sclerostin ( SOST ), and E11/gp38/podoplanin ( E11 ). In contrast, these cells did not express the odontoblast/dentin marker dentin sialoprotein ( DSPP ). HCY-23 cells produced mineral-like nodules in vitro under differentiation conditions, and were highly responsive to inorganic phosphate (Pi). Within the limits of the present study, it can be concluded that cementocytes are phosphate-responsive cells, and have the potential do play a key role in periodontal homeostasis and regeneration.

Microtensile bond strength of root canal dentin treated with adhesive and fiber-reinforced post systems

Abstract Nowadays, demand for esthetic restorations has risen considerably; thus, nonmetal esthetic posts made of either high-strength ceramics or reinforced resins, such as fiber-reinforced resin posts, have become more and more popular. Important characteristics of fiber-reinforced posts involve a modulus of elasticity similar to dentin and their ability to be cemented by an adhesive technique. A total of 36 maxillary incisors were divided into four groups. In this study, four adhesively luted fiber-reinforced (glass fiber, quartz glass fiber, zirconia glass fiber and woven polyethylene fiber ribbon) post systems were used. Post spaces were prepared by employing drills according to the protocol established for each group, and each post was adhesively luted with one of three adhesive systems. Three segments per root apical to the cementoenamel junction (CEJ) were obtained by sectioning the root under distilled water with a carbon spare saw. The samples (total of 108 sections) were 2.0±0.1 mm in thickness and they were stored individually in black film canisters with sterile distilled water. In order to determine the bond strength, the bonding area of each specimen was measured, and specimens were attached to a device to test microtensile strength at a speed of 1 mm/min. The analyses revealed no statistically significant differences between the adhesive systems and fiber-reinforced posts. (P> 0.05). However, the coronal portion of the root dentin had the highest bond strength. Adhesive systems used along with fiber-reinforced resin posts demonstrated reliable bonding.

Research progress in laser treatment of dentin hypersensitivity / 口腔疾病防治

@#Dentin hypersensitivity is mainly associated with abrasion, wear, acid etching, cracking, wedge-shaped defects, enamel hypoplasia, caries, a lack of neck enamel, and cementum coverage accompanied by gingival recession, resulting in direct exposure of dentin tubules to the oral environment. Dentin hypersensitivity is mainly treated by sealing the exposed dentin tubules and reducing the excitability of the pulpal nerves. Laser therapy, as a safe, fast and convenient treatment measure, has achieved good results both alone and in combination with other medicines and has attracted increasing attention. This paper reviews the research progress in the treatment of dentin hypersensitivity using several common laser therapy mechanisms with parameter selections in various scopes of application. A review of the literature shows that the Nd:YAG laser has a strong penetrating power and a large thermal effect and can denature and coagulate proteins in dentin tubules in a very short time; while the CO2 laser causes little damage to the dental pulp and has an obvious immediate curative effect by high absorption of water molecules in hydroxyapatite and the dentin surface is melted and recrystallized; the Er:YAG laser has high water absorption and a large thermal effect and can block the tubules by evaporating the fluid in the tubules and depositing salts; Er, Cr:YSGG laser energy can be fully absorbed by hydroxyapatite and water and result in desensitization by cutting hard tissues and melting periodontal dentin of the tube simultaneously; The Ga-Al-As semiconductor laser and He:Ne laser are low energy. The laser dosage mainly changes the permeability of nerve fibers to potassium and sodium ions and depolarizes the nerve fibers, producing an analgesic effect. The combination of a laser with a desensitizer can improve the clinical efficacy of treating dentin hypersensitivity.

Preparation of lithium-doped poly-glycerol sebacate scaffold and its properties / 吉林大学学报(医学版)

Objective:To prepare the lithium-doped poly-glycerol sebacate (PGS-Li) scaffold using the specific effects of lithium ions and the excellent performance of PGS, and to provide the basis for its application prospects in cementation tissue engineering scaffold.Methods:The scaffolds were divided into two groups.The PGS-Li scaffolds prepared by adding lithium phosphate during the PGS cross-linking process were used as PGS-Li group, and the PGS scaffolds synthesized by the equal-purification of sebacic acid and glycerol were used as PGS group.The molecular weights of the scaffolds in two groups were determined by gel permeation chromatography.The structures of the scaffolds in two groups were analyzed by fourier transform infrared spectroscope.The surface morphology and the porosities and the pore sizes of the scaffolds in two groups were observed by scanning electron microscope.X-ray photoelectron (XPS) spectroscope and inductively coupled plasma optical emission spectrometer were used to determine the Li ion contents in the scaffolds in two groups.Thermogravimetric analyzer was used to analyze the thermal stabilities of the scaffolds in two groups.Contact angle measuring instrument was used to compare the hydrophilicities of the scaffolds in two groups.In vitro weight loss test was used to determine the degradation rates of the scaffolds in two groups.The OCCM-30cells were divided into experimental group (added with PGS-Li scaffold extract) , PGS group (added with PGS scaffold extract) and blank control group (added with DMEM culture medium) .MTT assay was used to detect the proliferation activities of cells in various groups at different time (24, 48and 72h) ;the cell morphology was observed by calcein-AM staining.Results:The gel permeation chromatography results showed that the molecular weight of the PGS-Li scaffold was slightly larger than that of the PGS scaffold.The specific absorption peak of phosphate was detected in the fourier infrared spectrum of the PGS-Li scaffold.The scaffolds in two groups had irregular three-dimensional network structures under scanning electron microscope, and the pore size was 20-160μm, the porosity of PGS scaffold was (53.92±2.18) ％, and the porosity of PGS-Li scaffold was (53.58±1.73) ％, there was no statistical difference between two groups (P＞0.05) .The XPS results showed that a peak appeared at 54.9eV in PGS-Li group, which coincided with the Li 1s binding energy, while the inductively coupled plasma emission spectrometer results showed that the Li ion content in the PGS-Li scaffold was 0.084％.The thermogravimetric analysis results showed that PGS-Li scaffolds began to degrade at a higher temperature and ceased at a lower temperature compared with PGS scaffolds.The contact angle measurement results indicated that both the materials were hydrophilic materials;the contact angle of PGS scaffold meterial was 78.26°±2.00°, and the contact angle of the PGS-Li scaffold material was 69.78°±1.15°;there was statistical difference between two groups (P＜0.05) .The in vitro degradation experiments showed that the degradation rate of PGS-Li scaffolds was faster than that of PGS scaffolds.The proliferation activity of OCCM-30cells in PGS-Li group had no significant difference compared with PGS group and blank control group (P＞0.05) .The calcein-AM staining results showed the green fluorescence in the OCCM-30cells in PGS and PGS-Li groups, and there were no significant changes in the morphology of cementoblasts.Conclusion:PGS-Li scaffolds have similar composition and structure to PGS scaffolds, and have better performance in hydrophilicity and thermal stability.PGS-Li scaffolds have no effect on the proliferation of cementoblasts and have broad application prospects in cementum tissue engineering.

Research progress on the pathogenesis of inflammatory external root resorption / 华西口腔医学杂志

Inflammatory external root resorption (IERR) refers to the pathological process of dissolving the hard tissue on the outer surface of the tooth root by the body's own immune system under the stimulation of various physical and chemical factors such as infection, stress, trauma and orthodontic treatment. Severe IERR can lead to endodontic and periodontal diseases, and even the loss of teeth. Therefore, understanding the etiology and the pathogenic mechanism of IERR are of importance in its prevention and treatment. This article will review the etiology and the regulation mechanisms of IERR.

Hipercementosis, una alteración de la estructura dentaria: recopilación bibliográfica / Hypercementosis, an alteration of the dental structure: bibliographic compilation

La hipercementosis se presenta como depósitos de cemento en la raíz de uno o más dientes. Siendo más frecuente en dientes que están sometidos a fuerzas de oclusión, particularmente en pacientes con enfermedad de Paget. El aumento de cemento se depositará en una banda que se encuentra situada alrededor del tercio apical de la raíz, es de ayuda útil realizar una evaluación radiográfi ca antes de una extracción dental (AU)

Hypercementosis occurs as cement deposits in the root of one or more teeth. Being more frequent in teeth that are subjected to occlusion forces or in patients with Paget's disease. The cement increase can be deposited in a band that can be found near the apical third of the root, it is a dental aid that a radiographic evaluation is made before a dental extraction (AU)