Depletion of SNRNP200 inhibits the osteo-/dentinogenic differentiation and cell proliferation potential of stem cells from the apical papilla.

BACKGROUND: Tissue regeneration mediated by mesenchymal stem cells (MSCs) is deemed a desirable way to repair teeth and craniomaxillofacial tissue defects. Nevertheless, the molecular mechanisms about cell proliferation and committed differentiation of MSCs remain obscure. Previous researches have proved that lysine demethylase 2A (KDM2A) performed significant function in the regulation of MSC proliferation and differentiation. SNRNP200, as a co-binding factor of KDM2A, its potential effect in regulating MSCs' function is still unclear. Therefore, stem cells from the apical papilla (SCAPs) were used to investigate the function of SNRNP200 in this research. METHODS: The alkaline phosphatase (ALP) activity assay, Alizarin Red staining, and osteogenesis-related gene expressions were used to examine osteo-/dentinogenic differentiation potential. Carboxyfluorescein diacetate, succinimidyl ester (CFSE) and cell cycle analysis were applied to detect the cell proliferation. Western blot analysis was used to evaluate the expressions of cell cycle-related proteins. RESULTS: Depletion of SNRNP200 caused an obvious decrease of ALP activity, mineralization formation and the expressions of osteo-/dentinogenic genes including RUNX2, DSPP, DMP1 and BSP. Meanwhile, CFSE and cell cycle assays revealed that knock-down of SNRNP200 inhibited the cell proliferation and blocked cell cycle at the G2/M and S phase in SCAPs. In addition, it was found that depletion of SNRNP200 up-regulated p21 and p53, and down-regulated the CDK1, CyclinB, CyclinE and CDK2. CONCLUSIONS: Depletion of SNRNP200 repressed osteo-/dentinogenic differentiation potentials and restrained cell proliferation through blocking cell cycle progression at the G2/M and S phase, further revealing that SNRNP200 has crucial effects on preserving the proliferation and differentiation potentials of dental tissue-derived MSCs.

Gestational diabetes mellitus affects odontoblastic differentiation of dental papilla cells via Toll-like receptor 4 signaling in offspring.

Gestational diabetes mellitus (GDM) is an important factor involved in the pathogenesis of organ development in the offspring. Here, we analyzed the effects of GDM on odontoblastic differentiation of dental papilla cells (DPCs) and dentin formation in offspring and investigated their underlying mechanisms. A GDM rat model was induced by intraperitoneal injection of streptozotocin and offspring were collected. The results showed that GDM significantly affected odontoblast differentiation and dentin formation in offspring tooth. GDM activated the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-ĸB) signaling pathway and inhibited SMAD1/5/9 signaling to modulate the odontoblastic differentiation of DPCs in offspring. Inhibition of TLR4 signaling by treated with TAK-242 significantly reverses the suppression of odonto-differentiation of DPCs in diabetic offspring. Taken together, these data indicate GDM activated the offspring DPCs TLR4/NF-ĸB signaling, which suppressed the SMAD1/5/9 phosphorylation and then inhibited odontoblasts differentiation and dentin formation.

Expression of CPNE7 during mouse dentinogenesis.

Interactions between the ectodermal and mesenchymal tissues are the basis of the central mechanism regulating tooth development. Based on this epithelial-mesenchymal interaction (EMI), we demonstrated that copine-7 (CPNE7) is secreted by preameloblasts and regulates the differentiation of mesenchymal cells of dental or non-dental origin into odontoblasts. However, the precise expression patterns of CPNE7 in the stages of tooth development have not yet been elucidated. The aim of the present study was to establish the spatiotemporal expression pattern of CPNE7 during mouse tooth development. To examine the spatiotemporal expression patterns of CPNE7 during mouse tooth development, we investigate the distribution of CPNE7 in the embryonic and postnatal developing mouse tooth. Immunohistochemistry, in situ hybridization, real-time PCR, and western blot analysis are performed to investigate the CPNE7 expression pattern during tooth development of the mandibular mouse first molar. During the initiation stage (bud stage), CPNE7 protein expression is observed in the dental epithelium but not yet in the dental mesenchyme. At E18 (bell stage), expression of CPNE7 protein and mRNA is primarily observed in ectomesenchymal cells of dental papilla. At P7 (crown formation stage), CPNE7 is localized in differentiating odontoblasts but weak expression is detected in mature ameloblasts. These findings suggest that CPNE7 secreted by dental epithelium induces the differentiation of ectomesenchymal cells into preodontoblast in concert with EMI. CPNE7 is clearly expressed in differentiating odontoblasts and the odontoblast process during dentinogenesis, but is no longer expressed in fully differentiated odontoblasts. Furthermore, CPNE7 is expressed in the Hertwig's epithelial root sheath (HERS) and in the facing preodontoblasts during root dentin formation. Taken together, these results illustrate the dynamic expression of CPNE7 during tooth development and suggest its important function in entire stages of tooth development.

The role of Rho-GEF Trio in regulating tooth root development through the p38 MAPK pathway.

Trio, the Rho guanine nucleotide exchange factor (Rho-GEF), plays diverse roles in cell migration, cell axon guidance and cytoskeleton reorganization. Conserved during evolution, Trio encodes two guanine nucleotide exchange factor domains (GEFs) and activates small GTPases. The Rho-family small GTPases RhoA and Rac1, which are target molecules of Trio, have been described to engage in craniofacial development and tooth formation. However, the exact role of Trio in tooth development remains elusive. In this study, we generated Wnt1-cre;Triofl/fl mice to address the potential function of Trio in tooth development. Wnt1-cre;Triofl/fl mice showed short root deformity as well as decreased expression of odontogenic makers such as RUNX2, OSX, OCN, and OPN. In vitro, Trio was silenced in human stem cells of dental papilla (SCAPs). Compared with the control group, the proliferation and migration ability in the experimental group was disrupted. After knocking down Trio in SCAPs, the cells showed phenotypes of poor odontogenic differentiation and weak mineralized nodules. To study the underlying mechanism, we investigated the p38 MAPK pathway and found that loss of Trio blocked the cascade transduction of p38 MAPK signaling. In conclusion, we identified Trio as a novel coordinator in regulating root development and clarified its relevant molecular events.

Effect of Bioceramic Materials on Proliferation and Odontoblast Differentiation of Human Stem Cells from the Apical Papilla.

INTRODUCTION: In regenerative endodontic treatment (RET), practitioners favor the placement of bioceramics as sealing materials over blood clots. It is important to understand the interaction between sealing material and cells in the root canal. The purpose of this study was to compare the effectiveness of various bioceramic materials (ProRoot MTA [Dentsply, Tulsa, OK], Biodentine [Septodont, Saint-Maur-des-Fossés, France], and RetroMTA [BioMTA, Seoul, Korea]) as sealing materials in RET for the proliferation and differentiation of stem cells from the apical papilla (SCAPs). METHODS: SCAPs were seeded at 20,000 cells/well and cultured with soluble agents of testing materials through a transwell culture plate. The proliferation of SCAPs was investigated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on days 1, 3, 7, and 14 of testing. Alizarin red staining and quantitative real-time polymerase chain reaction were used for SCAP differentiation at different time points (1, 7, 14, and 21 days). The odontoblast genes expressed are dentin matrix acidic phosphoprotein 1, dentin sialophosphoprotein, osteocalcin, and matrix extracellular phosphoglycoprotein, which were used in this study. The SCAPs were cultured in odonto/osteogenic induction medium and also contacted soluble agents from the testing materials. RESULTS: All 3 tested biomaterials induced SCAP proliferation. The Biodentine, ProRootMTA, and RetroMTA groups showed significant SCAP proliferation on days 7 and 14 compared with the control. In regard to odontoblastic differentiation, only Biodentine showed positive alizarin red staining. The highest expressions of dentin matrix acidic phosphoprotein 1, dentin sialophosphoprotein, and matrix extracellular phosphoglycoprotein were found on day 21 in the Biodentine group. The expression of osteocalcin was found to be significant on day 7. CONCLUSIONS: Biodentine, ProRootMTA, and RetroMTA can induce SCAP proliferation. Biodentine induced significant SCAP differentiation among the 3 materials.

Dynamic Irrigation Promotes Apical Papilla Cell Attachment in an Ex Vivo Immature Root Canal Model.

INTRODUCTION: The use of dentin preconditioning techniques in regenerative endodontic procedures is currently promising. Several growth factors have been detected on dentin after ultrasonic irrigation with EDTA. This study aimed to evaluate the effects of dynamic irrigation with different solution regimens on apical papilla cell (APC) attachment in an ex vivo immature tooth model. METHODS: Various dynamic irrigation techniques, needle irrigation (NI), NI with EndoActivator, and NI with passive ultrasonic irrigation, were used with different solution regimens, normal saline solution (NSS), EDTA, and chlorhexidine digluconate followed by EDTA, in enlarged root canal models where calcium hydroxide-medicated dentin slices were inserted. The initial number of attached fibronectin-positive APCs was counted. Dentin surface morphology was also inspected by using scanning electron microscopy. RESULTS: The number of APCs was significantly greater in the dynamic irrigation groups than in the control group (P < .001). Greater APC numbers were observed in the groups in which NSS was used than in those in which EDTA or chlorhexidine digluconate/EDTA was used, when using the same techniques (P < .001). Cell numbers were similar at all levels of the root canals; however, in the ultrasonically supplemented group irrigated with NSS, the number of attached cells was significantly increased at the middle and apical levels (P < .05). CONCLUSIONS: The use of dynamic irrigation techniques in an immature tooth model definitely promoted APC attachment to calcium hydroxide-medicated dentin. Furthermore, when NSS was used as a final irrigant, the number of attached cells was significantly increased.

Bivalent Histone Codes on WNT5A during Odontogenic Differentiation.

Lineage-committed differentiation is an essential biological program during odontogenesis, which is tightly regulated by lineage-specific genes. Some of these genes are modified by colocalization of H3K4me3 and H3K27me3 marks at promoter regions in progenitors. These modifications, named "bivalent domains," maintain genes in a poised state and then resolve for later activation or repression during differentiation. Wnt5a has been reported to promote odontogenic differentiation in dental mesenchyme. However, relatively little is known about the epigenetic modulations on Wnt5a activation during tooth development. Here, we investigated the spatiotemporal patterns of H3K4me3 and H3K27me3 marks in developing mouse molars. Associated H3K4me3 methylases (mixed-lineage leukemia [MLL] complex) and H3K27me3 demethylases (JMJD3 and UTX) were dynamically expressed between early and late bell stage of human tooth germs and in cultured human dental papilla cells (hDPCs) during odontogenic induction. Poised WNT5A gene was marked by bivalent domains containing repressive marks (H3K27me3) and active marks (H3K4me3) on promoters. The bivalent domains tended to resolve during inducted differentiation, with removal of the H3K27me3 mark in a JMJD3-dependent manner. When JMJD3 was knocked down in cultured hDPCs, odontogenic differentiation was suppressed. The depletion of JMJD3 epigenetically repressed WNT5A activation by increased H3K27me3 marks. In addition, JMJD3 could physically interact with ASH2L, a component of the MLL complex, to form a coactivator complex, cooperatively modulating H3K4me3 marks on WNT5A promoters. Overall, our study reveals that transcription activities of WNT5A were epigenetically regulated by the negotiated balance between H3K27me3 and H3K4me3 marks and tightly mediated by JMJD3 and MLL coactivator complex, ultimately modulating odontogenic commitment during dental mesenchymal cell differentiation.

Immunolocalization of connective tissue growth factor, transforming growth factor-beta1 and phosphorylated-SMAD2/3 during the postnatal tooth development and formation of junctional epithelium.

Connective tissue growth factor (CTGF) is a downstream mediator of transforming growth factor-beta 1 (TGF-ß1) and TGF-ß1-induced CTGF expression is regulated through SMAD pathway. However, there is no literature showing the expression of TGF-ß1-SMAD2/3-CTGF signaling pathway during postnatal tooth development and the formation of junctional epithelium (JE). Hence, we aimed to analyze the localization of TGF-ß1, CTGF and phosphorylated SMAD2/3 (p-SMAD2/3) in the developing postnatal rat molars. Wistar rats were killed at postnatal (PN) 0.5, 3.5, 7, 14 and 21days and the upper jaws were processed for immunohistochemistry. At PN0.5 and PN3.5, weak staining for TGF-ß1 and CTGF was evident in preameloblasts (PA), while moderate to strong staining was seen in odontoblasts (OD), dental papilla (DPL), secretary ameloblasts (SA), preodontoblasts (PO) and polarized odontoblasts (PoO). There was no staining for p-SMAD2/3 in PA, SA, PO and PoO, although strong staining was localized in DPL. OD was initially moderately positive and then negative for p-SMAD2/3. At PN7, intense staining for TGF-ß1 and CTGF was observed in SA, OD, dental pulp (DP) and predentin respectively. p-SMAD2/3 was strongly expressed in DP and moderately expressed in SA and OD. At PN14 and PN21, both reduced enamel epithelium (REE) and JE showed a strong reaction for TGF-ß1 and CTGF. p-SMAD2/3 was intensely and weakly expressed in REE and JE respectively. These data demonstrate that the expression of CTGF, TGF-ß1 and p-SNAD2/3 is tissue-specific and stage-specific, and indicate a regulatory role for a TGF-ß1-SMAD2/3-CTGF signaling pathway in amelogenesis, dentinogenesis and formation of JE.

Effects of Lipopolysaccharide on the Proliferation and Osteogenic Differentiation of Stem Cells from the Apical Papilla.

INTRODUCTION: Stem cells from the apical papilla (SCAPs) were suggested as the stem cell source in regenerative endodontic procedures. However, bone and/or cementum-like structure were observed in root canals. Lipopolysaccharide (LPS) in infected root canals might alter SCAPs' osteogenic differentiation pattern. The objectives of this study were to investigate the effects of LPS on SCAPs' proliferation and osteogenic differentiation. METHODS: The mesenchymal stem cell characteristics of SCAPs were confirmed. Cell viability was tested with Porphyromonas gingivalis LPS at concentration between 0.001 and 5 µg/mL. SCAPs were pretreated with those concentrations for 168 hours. Then SCAPs were further investigated for cell proliferation by resazurin-based assay. Mineralization capacity was determined by alizarin red S staining. Odontoblast marker was determined by DSPP gene expression. General bone and cementum markers, BSP and OPN, were also determined. Determination of the expression levels of these genes was performed by polymerase chain reaction. RESULTS: SCAPs demonstrated the mesenchymal stem cell characteristics. All LPS concentrations did not affect cell viability. Pretreatment with LPS also did not affect cell proliferation and mineralization in every concentration. There was no significant difference between DSPP and OPN gene expression levels at all concentrations. However, LPS at 5 µg/mL significantly increased BSP gene expression. CONCLUSIONS: Under the limitations of this in vitro study, LPS did not affect SCAP proliferation and mineralization. However, LPS at high concentration, 5 µg/mL, increased BSP gene expression.

Effect of Bacterial Biofilm on the Osteogenic Differentiation of Stem Cells of Apical Papilla.

INTRODUCTION: Although clinical success in regenerative endodontics is substantially high, histological success is limited to finding bone/cementum-like tissue instead of dentin within the canal space. The aims of this study were to investigate (1) the effect of bacterial biofilm on osteogenic gene expression in stem cells of the apical papilla (SCAP) and (2) the effect of bacterial antigens on the functional differentiation of SCAP into a mineralizing phenotype. METHODS: Using an ex vivo organotypic root canal model and an American Association of Endontists-recommended regenerative endodontic procedures, we evaluated SCAP differentiation in the presence and absence of an Enterococcus faecalis biofilm. Gene expression analysis for dentinogenic and osteoblastic markers was performed with real-time polymerase chain reaction. The effect of E. faecalis antigens on SCAP differentiation into mineralizing cells in vitro was evaluated with 2 functional assays: Alizarin Red and alkaline phosphatase activity assays. RESULTS: After regenerative endodontic procedures, residual bacteria continued to sustain within the root canal system. SCAP in the presence of E. faecalis biofilm significantly downregulated dentinogenic genes such as dentin sialophosphoprotein and upregulated osteoblastic genes such as bone sialoprotein, osteocalcin, distal-less homeobox 5, and runt-related transcription factor 2. E. faecalis antigens significantly inhibited SCAP differentiation into a mineralizing phenotype when alizarin red staining and alkaline phosphatase assays were used in vitro. CONCLUSIONS: Current disinfection protocols were ineffective in eliminating bacteria from root tips and the levels of the residual bacterial biofilm, and its byproducts, were able to significantly alter osteogenic-differentiation of SCAP.

Comparison of stem cell behaviors between indigenous high and low-CD24 percentage expressing cells of stem cells from apical papilla (SCAPs).

CD24 was suggested as a marker to SCAPs and has been reported for a decade. CD24 has been shown to involve stem cell activities such as self-renewal, proliferation and differentiation. However, the percentage variations of CD24 positive cells were reported among the studies. It is possible that this variation may affect these SCAPs behaviors. In this study, the variation was confirmed. To elucidate the influence of CD24 positive cells quantity on SCAPs stem cell behaviors, the 3 cell lines with the most maximum and the least numbers of CD24 positive cells (High-CD24 and Low-CD24 group) were selected to study. Both groups expressed the same mesenchymal stem cell markers and negative to hematopoietic marker. High-CD24 group demonstrated less self-renewal capacity by lower colony-forming-unit count and pluripotency marker gene expressions. However, cell proliferation was not different. In contrast, osteogenic and adipogenic differentiation were better than Low-CD24 group. The early stage of root development demonstrated higher CD24 expressing cells than later stage. In conclusion, quantity of CD24 expressing cells influenced SCAPs self-renewal and multi-lineage differentiation but did not influence on cell proliferation. Stage of root development influenced to CD24 expressing cell numbers.

Complication After Extraction of Natal Teeth with Continued Growth of a Dental Papilla.

The purposes of this case report were to describe a growing two-cm gingival mass that developed after natal teeth were extracted in a four-month-old female patient, present a review of the literature on the growth of a gingival mass after the extraction of natal teeth, and illustrate the clinical and histological features that differentiate this condition from other types of gingival masses in infants. Histological examination of the excised mass revealed that it contained tooth-like hard tissue (regular and irregular dentin) that intermingled with bone, dental pulp, and fibrous tissue. We found eight cases from 1962 to 2009 in which a soft-tissue mass with dentin-like hard tissue or a tooth-like structure had developed after the extraction of natal teeth. Based on clinical and histological findings, we deduced that the mass was the result of abnormal growth of a residual dental papilla, including mesenchymal stem cells. Consequently, dentists, obstetricians, gynecologists, and pediatricians should be aware of this potential complication and observe caution before they extract natal teeth.

Analysis of expression patterns of IGF-1, caspase-3 and HSP-70 in developing human tooth germs.

AIMS: To analyze expression patterns of IGF-1, caspase-3 and HSP-70 in human incisor and canine tooth germs during the late bud, cap and bell stages of odontogenesis. MATERIALS AND METHODS: Head areas or parts of jaw containing teeth from 10 human fetuses aged between 9th and 20th developmental weeks were immunohistochemically analyzed using IGF-1, active caspase-3 and HSP-70 markers. Semi-quantitative analysis of each marker's expression pattern was also performed. RESULTS: During the analyzed period, IGF-1 and HSP-70 were mostly expressed in enamel organ. As development progressed, expression of IGF-1 and HSP-70 became more confined to differentiating tissues in the future cusp tip area, as well as in highly proliferating cervical loops. Few apoptotic bodies highly positive to active caspase-3 were observed in enamel organ and dental papilla from the cap stage onward. However, both enamel epithelia moderately expressed active caspase-3 throughout the investigated period. CONCLUSIONS: Expression patterns of IGF-1, active caspase-3 and HSP-70 imply importance of these factors for early human tooth development. IGF-1 and HSP-70 have versatile functions in control of proliferation, differentiation and anti-apoptotic protection of epithelial parts of human enamel organ. Active caspase-3 is partially involved in formation and apoptotic removal of primary enamel knot, although present findings might reflect its ability to perform other non-death functions such as differentiation of hard dental tissues secreting cells and guidance of ingrowth of proliferating cervical loops.

Establishment of Immortalized Mouse Bmp2 Knock-Out Dental Papilla Mesenchymal Cells Necessary for Study of Odontoblastic Differentiation and Odontogenesis.

Bmp2 is essential for dentin formation. Bmp2 cKO mice exhibited similar phenotype to dentinogenesis imperfecta, showing dental pulp exposure, hypomineralized dentin, and delayed odontoblast differentiation. As it is relatively difficult to obtain lot of primary Bmp2 cKO dental papilla mesenchymal cells and to maintain a long-term culture of these primary cells, availability of immortalized deleted Bmp2 dental papilla mesenchymal cells is critical for studying the underlying mechanism of Bmp2 signal in odontogenesis. In this study, our goal was to generate an immortalized deleted Bmp2 dental papilla mesenchymal (iBmp2(ko/ko)dp) cell line by introducing Cre recombinase and green fluorescent protein (GFP) into the immortalized mouse floxed Bmp2 dental papilla mesenchymal (iBmp2(fx/fx)dp) cells. iBmp2(ko/ko)dp cells were confirmed by GFP and PCR. The deleted Bmp2 cells exhibited slow cell proliferation rate and cell growth was arrested in G2 phase. Expression of tooth-related marker genes and cell differentiation were decreased in the deleted cells. Importantly, extracellular matrix remodeling was impaired in the iBmp2(ko/ko)dp cells as reflected by the decreased Mmp-9 expression. In addition, with exogenous Bmp2 induction, these cell differentiation and mineralization were rescued as well as extracellular matrix remodeling was enhanced. Therefore, we for the first time described establishment of iBmp(ko/ko) cells that are useful for study of mechanisms in regulating dental papilla mesenchymal cell lineages.

Immortalized Mouse Floxed Fam20c Dental Papillar Mesenchymal and Osteoblast Cell Lines Retain Their Primary Characteristics.

Fam20c is essential for the normal mineralization of dentin and bone. The generation of odontoblast and osteoblast cell lines carrying floxed Fam20c allele can offer valuable tools for the study of the roles of Fam20c in the mineralization of dentin and bone. The limited capability of the primary odontoblasts and osteoblasts to proliferate necessitates the development of odontoblast and osteoblast cell lines serving as substitutes for the study of differentiation and mineralization of the odontoblasts and osteoblasts. In this study, we established and characterized immortalized mouse floxed Fam20c dental papilla mesenchymal and osteoblast cell lines. The isolated primary mouse floxed Fam20c dental papilla mesenchymal cells and osteoblasts were immortalized by the infection of lentivirus containing Simian Virus 40 T-antigen (SV40 T-Ag). The immortalization of floxed Fam20c dental papilla mesenchymal cells and osteoblasts was verified by the long-term passages and genomic integration of SV40 T-Ag. The immortalized floxed Fam20c dental papilla mesenchymal and osteoblast cell lines not only proliferated at a high rate and retained the morphology of their primary counterparts, but also preserved the dentin and bone specific gene expression as the primary dental papilla mesenchymal cells and osteoblasts did. Consistently, the capability of the primary floxed Fam20c dental papilla mesenchymal cells and osteoblasts to mineralize was also inherited by the immortalized dental papilla mesenchymal and osteoblast cell lines. Thus, we have successfully generated the immortalized mouse floxed Fam20c dental papilla mesenchymal and osteoblast cell lines.

Bone morphogenetic protein-9 effectively induces osteo/odontoblastic differentiation of the reversibly immortalized stem cells of dental apical papilla.

Dental pulp/dentin regeneration using dental stem cells combined with odontogenic factors may offer great promise to treat and/or prevent premature tooth loss. We previously demonstrated that bone morphogenetic protein 9 (BMP9) is one of the most potent factors in inducing bone formation. Here, we investigate whether BMP9 can effectively induce odontogenic differentiation of the stem cells from mouse apical papilla (SCAPs). Using a reversible immortalization system expressing SV40 T flanked with Cre/loxP sites, we demonstrate that the SCAPs can be immortalized, resulting in immortalized SCAPs (iSCAPs) that express mesenchymal stem cell markers. BMP9 upregulates Runx2, Sox9, and PPARγ2 and odontoblastic markers, and induces alkaline phosphatase activity and matrix mineralization in the iSCAPs. Cre-mediated removal of SV40 T antigen decreases iSCAP proliferation. The in vivo stem cell implantation studies indicate that iSCAPs can differentiate into bone, cartilage, and, to lesser extent, adipocytes upon BMP9 stimulation. Our results demonstrate that the conditionally iSCAPs not only maintain long-term cell proliferation but also retain the ability to differentiate into multiple lineages, including osteo/odontoblastic differentiation. Thus, the reversibly iSCAPs may serve as an important tool to study SCAP biology and SCAP translational use in tooth engineering. Further, BMP9 may be explored as a novel and efficacious factor for odontogenic regeneration.

c-kit positive cells and networks in tooth germs of human midterm fetuses.

Numerous studies have attempted to characterize the dental pulp stem cells. However, studies performed on prenatal human tissues have not been performed to evaluate the in situ characterization and topography of progenitor cells. We aimed to perform such a study using of antibodies for CD117/c-kit and multiplex antibody for Ki67+ caspase 3. Antibodies were applied on samples dissected from five human midterm fetuses. Positive CD117/c-kit labeling was found in mesenchymal derived tissues, such as the dental follicle and the dental papilla. The epithelial tissues, that is, dental lamina, enamel organ and oral epithelia, also displayed isolated progenitor cells which were CD117/c-kit positive. Interestingly, CD117/c-kit positive cells of mesenchymal derived tissues extended multiple prolongations building networks; the most consistent of such networks were those of the dental follicle and the perivascular networks of the dental papilla. However, the mantle of the dental papilla was also positive for CD117/c-kit positive stromal networks. The CD117/c-kit cell populations building networks appeared mostly with a Ki67 negative phenotype. The results suggest that CD117/c-kit progenitor cells of the prenatal tooth germ tissues might be involved in intercellular signaling.

Immortalized mouse dental papilla mesenchymal cells preserve odontoblastic phenotype and respond to bone morphogenetic protein 2.

Odontogenesis is the result of the reciprocal interactions between epithelial-mesenchymal cells leading to terminally differentiated odontoblasts. This process from dental papilla mesenchymal cells to odontoblasts is regulated by a complex signaling pathway. When isolated from the developing tooth germs, odontoblasts quickly lose their potential to maintain the odontoblast-specific phenotype. Therefore, generation of an odontoblast-like cell line would be a good surrogate model for studying the dental mesenchymal cell differentiation into odontoblasts and the molecular events of dentin formation. In this study, immortalized dental papilla mesenchymal cell lines were generated from the first mouse mandibular molars at postnatal day 3 using pSV40. These transformed cells were characterized by RT-PCR, immunohistochemistry, Western blot, and analyzed for alkaline phosphatase activity and mineralization nodule formation. One of these immortalized cell lines, iMDP-3, displayed a high proliferation rate, but retained the genotypic and phenotypic characteristics similar to primary cells as determined by expression of tooth-specific markers and demonstrated the ability to differentiate and form mineralized nodules. Furthermore, iMDP-3 cells had high transfection efficiency as well as were inducible and responded to BMP2 stimulation. We conclude that the establishment of the stable murine dental papilla mesenchymal cell line might be used for studying the mechanisms of dental cell differentiation and dentin formation.

[Combined crown lengthening surgery with restorative therapy for inducing papilla growth: a case report].

A young lady with unsatisfied restorations of upper anterior teeth and swollen gum wanted to improve aesthetics. Oral examination showed that 12-22 were provisional crowns with normal occlusion, poorly gingival contour and gummy smile. The gingiva was red, light swollen and bleeding on probing. X-ray showed the roots of 11, 21 were short and the alveolar bone absorbed. After the periodontal initial treatment, an ideal location of gingival margin was determined. Then, an esthetic periodontal surgery was performed to recover the biology width and the gingival margin was fitted with the anterior teeth. The temporary restorations were made twice to guide the gingiva growth by changing the shape of the restorations and moving up the contact points of the restorations. The ceramic crowns were completed 3 months after the operation. The gummy smile disappeared and the gingival margin was filled well with the upper anterior ceramic crowns. The 14-month follow-up presented a satisfied effect. Crown lengthening surgery combined restorative therapy could lead papilla to grow well. This process is beneficial for the future treatment plan and clinical esthetic evaluation.

Abordagens previsíveis para preservação e formação de papilas em implantodontia / Predictable approaches papilla preservation and formation in implantology

Esta monografia apresenta uma revisão de literatura acerca das possibilidades de preservação e formação de papila em implantodontia, abordando técnicas previsíveis para obtenção de resultados estéticos favoráveis quando da reabilitação com implantes na região anterior. Com o intuito de se padronizar critérios de relevância para avaliação desses resultados e antevê-los, vários trabalhos utilizam dois índices importantes...