Phosphophoryn Research Articles

Clinical and molecular factors associated with external apical root resorption by orthodontics: Umbrella review

The objective of this study was to analyze the available evidence on external apical root resorption (EARR) due to orthodontic movement to identify clinical and molecular factors associated with this condition. An umbrella review that included systematic reviews and meta-analysis was performed. Four databases were used (PubMed, Science Direct, Scopus, and Cochrane), and critical evaluation following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and admeasurement tool to assess systematic reviews (AMSTAR-2) guidelines were carried out. The study protocol was registered in PROSPERO (International prospective register of systematic reviews, CRD42020198971). One hundred and twenty-four papers were eligible for this investigation. After exclusion by title and abstract, 10 papers (four systematic reviews and six meta-analyses) were included in the study. Guideline AMSTAR-2 was applied, and evaluation was performed using the PRISMA guideline. Factors such as female gender, adulthood, conventional fixed orthodontic treatment, heavy, continuous, and prolonged loads, intrusive movements, and anterior superior teeth with abnormal roots increase the risk of developing this condition. At the molecular level, some biomarkers, such as interleukins (IL) I-1B, I-6, I-4, and dentin phosphoprotein, are significant to reach an early diagnosis of external root resorption (ERR), especially the gene of polymorphism IL-1B (+3954), which is the most important predictor of this condition in patients under orthodontic treatment. Clinical and molecular factors respond to individual characteristics that must be identified to define the risk of developing EARR. Cone-beam computed tomography is the most accurate tool to evaluate the dimension of this condition. Prolonged treatments must be avoided, and immunoassays to analyze proteins in the gingival crevicular fluid should be included to reach an early diagnosis.

Novel dentin sialophosphoprotein gene frameshift mutations affect dentin mineralization

ObjectiveThis study aimed to identify candidate genes for inheritable dentin defects in three Chinese pedigrees and characterize the property of affected teeth. DesignClinical and radiological features were recorded for the affected individuals. Genomic DNA obtained from peripheral venous blood or saliva were analyzed by whole-exome sequencing. The density and microhardness of affected dentin was measured. Scanning electron microscopy (SEM) was also performed to obtain the microstructure phenotype. Results1) General appearance: the affected dentitions shared yellowish-brown or milky color. Radiographs showed that the pulp cavity and root canals were obliterated in varying degrees or exhibited a pulp aspect in the ‘thistle tube’. Some patients exhibited periapical infections without pulpal exposure, and some affected individuals showed shortened, abnormally thin roots accompanied by severe alveolar bone loss. 2) Genomic analysis: three new frameshift mutations (NM_014208.3: c.2833delA, c.2852delGand c.3239delA) were identified in exon 5 of dentin sialophosphoprotein (DSPP) gene, altering dentin phosphoprotein (DPP) as result. In vitro studies showed that the density and microhardness of affected dentin were decreased, the dentinal tubules were sparse and arranged disorderly, and the dentinal-enamel-junction (DEJ) was abnormal. ConclusionsIn this study, we identified three novel frameshift mutations of dentin sialophosphoprotein gene related to inherited dentin defects. These mutations are speculated to cause abnormal coding of dentin phosphoprotein C-terminus, which affect dentin mineralization. These results expand the spectrum of dentin sialophosphoprotein gene mutations causing inheritable dentin defects and broaden our understanding of the biological mechanisms by which dentin forms.

A novel DSPP frameshift mutation causing dentin dysplasia type 2 and disease management strategies.

The present study aims to investigate the mutation in a Chinese family with dentin dysplasia type II (DD-II) and to summarize mutation hotspots, clinical manifestations, and disease management strategies. Phenotype analysis, clinical intervention, mutation screening, and cosegregation analysis within the enrolled family were performed. A summary of the reported mutations in the dentin phosphoprotein (DPP) region of dentin sialophosphoprotein (DSPP) was analyzed. Pathogenicity prediction analysis of the physical properties and function of DSPP variants was performed by bioinformatic processing. Clinical management strategies are discussed. A novel pathogenic mutation (c.2035delA) in the DPP region of DSPP was identified, which was cosegregated in the family. The immature permanent teeth of patients with DD-II presented with X-shaped root canal phenotypes. Most of the identified mutations for DD-II were clustered in the DPP region between nucleotides 1686-2134. Points of differential diagnosis, clinical interventions, and management strategies are proposed. This study revealed a novel DSPP frameshift mutation and presented new clinical features of DD-II. The locus involving nucleotides 1686-2134 of DSPP may represent a mutational hotspot for the disease. Appropriate management of DD-II at different stages is important to avoid the development of secondary dental lesions.

Withdrawal: A novel DSPP frameshift mutation causing dentin dysplasia type 2 and disease management strategies.

To investigate the mutation in two Chinese families with dentin dysplasia type II (DD-II) and to summarize mutation hotspots, clinical manifestations, and disease management strategies. Phenotype analysis, clinical intervention, mutation screening, and co-segregation analysis within the enrolled families were performed. A summary of the reported mutations in the dentin phosphoprotein (DPP) region of dentin sialophosphoprotein (DSPP) was analysed. Pathogenicity prediction analysis of the physical properties and function of DSPP variants were performed by bioinformatic processing. Clinical management strategies are discussed. A novel pathogenic mutation (c.2035delA) in the DPP region of DSPP was identified, which was co-segregated in the families of patients. The immature permanent teeth of patients with DD-II presented with X-shaped root canal phenotypes. Most of the identified mutations for DD-II were clustered in the DPP region between nucleotides 1686-2134. Points of differential diagnosis, clinical interventions, and management strategies are proposed. This study revealed a novel DSPP frameshift mutation and presented new clinical features of DD-II. The locus involving nucleotides 1686-2134 of DSPP may represent a mutational hotspot for the disease. Appropriate management of DD-II at different stages is important to avoid the development of secondary dental lesions.

Dentin Sialoprotein/Phosphophoryn (DSP/PP) as Bio-Inductive Materials for Direct Pulp Capping.

Conventional direct pulp capping, such as calcium hydroxide (Ca(OH)2) or silicate products, usually induces an inflammatory reaction to provoke pulp regeneration. Phosphophoryn (PP) and dentin sialoprotein (DSP), the two most abundant non-collagenous proteins in the dentin matrix, are responsible for dentin mineralization, pulp cell migration, and differentiation. Here we examined the PP and combined DSP/PP as bio-inductive pulp capping materials by in vitro and in vivo tests. Firstly, the effects of the PP dose on pulp cell migration and matrix protein expression were examined by an agarose bead test. Secondly, the role of recombinant DSP (recDSP) and recDSP/PP on stimulating DSP-PP transcript expression was examined by RT-PCR. DSPP mRNA was also knocked down by RNA interference (RNAi) to examine their functions on dentin matrix mineralization. Finally, we used ferret animal models to test PP and recDSP/PP acting as capping agents on in vivo pulp responses and reparative dentin formation. The result showed that intermediate-dose PP was the most effective to enhance cell migration and differentiation. RecDSP/PP strongly enhanced the DSP-PP transcript expression, while inhibition of DSPP mRNA expression by siRNAs partially or completely affected dental pulp cell mineralization. The in vivo results showed that intermediate-dose PP and recDSP/PP proteins induced less pulp inflammation and promoted reparative dentin formation. Contrarily, conventional calcium hydroxide induced severe pulp inflammation. With these findings, DSP and PP could serve as capping agents for pulp capping therapy.

The effect of two different types of forces on possible root resorption in relation to dentin phosphoprotein levels: a single-blind, split-mouth, randomized controlled trial

BackgroundThe purpose of this 2-arm-parallel split-mouth trial was to evaluate and compare the extent of possible root resorption using dentin phosphoprotein levels in gingival crevicular fluid between controlled continuous and intermittent orthodontic force groups.Materials and methodsA sample of 16 maxillary first premolars from 8 patients requiring bilateral extractions of the upper first premolars as part of their orthodontic treatment were recruited. A buccally directed continuous force of 150 g, reactivated after 28 days, was applied to the upper first premolar on one side for 8 weeks. On the contralateral first premolar, a buccally directed intermittent force (21 days on, 7 days off) of the same magnitude was applied for the same period. Gingival crevicular fluid samples were collected at the beginning of the study, 1st, 3rd, 4th and 5th week, and at the end of the study to quantify and compare dentin phosphoprotein levels in both groups.ResultsDentin phosphoprotein levels showed a higher concentration in the continuous force group than the intermittent force group in week 4 and 8 of sample collection; where the differences were statistically significant (95% CI 0.007–0.14; P < .04) and (95% CI 0.02–0.17; P < .04) respectively. No harm was observed.ConclusionsDentin phosphoprotein was found to be a useful early biomarker to detect and monitor root resorption, showing that the application of an intermittent orthodontic force caused less root resorption than a continuous force.Trial registrationNCT04825665 ClinicalTrials.gov. Registered 1 April 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04825665.

Enhancing osteoblast bioactivity through SDSSD peptide-immobilized on the surface of zirconia implants

Osseointegration is the cornerstone of successful implant restoration, although it is still difficult to achieve the current zirconia implants. In this study, we have modified zirconia implants with the Ser-Asp-Ser-Ser-Asp (SDSSD) peptide, a key osteoblast-targeting constituent of dentin phosphoprotein (DPP) to enhance osteogenesis. Our design involves a series of chemical approaches to immobilize SDSSD peptide on zirconia surface and investigate their brilliant binding strength, augment biocompatibility and osteogenic properties.

The Behavior of MDPC-23 Cells Modulated by DSPP

Phosphophoryn (PP) and Dentin Sialoprotein (DSP) are two of the most abundant dentin matrix non-collagenous proteins. These two proteins are derived from Dentin Sialophosphoprotein (DSPP) precursor protein cleavage by DMP1 protease.

The colocalizations of pulp neural stem cells markers with dentin matrix protein-1, dentin sialoprotein and dentin phosphoprotein in human denticle (pulp stone) lining cells

BackgroundThe primary dentin, secondary dentin, and reactive tertiary dentin are formed by terminal differentiated odontoblasts, whereas atubular reparative tertiary dentin is formed by odontoblast-like cells. Odontoblast-like cells differentiate from pulpal stem cells, which express the neural stem cell markers nestin, S100β, Sox10, and P0. The denticle (pulp stone) is an unique mineralized extracellular matrix that frequently occurs in association with the neurovascular structures in the dental pulp. However, to date, the cellular origin of denticles in human dental pulp is unclear. In addition, the non-collagenous extracellular dentin matrix proteins dentin matrix protein 1 (DMP1), dentin sialoprotein (DSP), and dentin phosphoprotein (DPP) have been well characterized in the dentin matrix, whereas their role in the formation and mineralization of the denticle matrix remains to be clarified. MethodsTo characterize the formation of denticle, healthy human third molars (n = 59) were completely sectioned and evaluated by HE staining in different layers at 720 µm intervals. From these samples, molars with (n = 5) and without denticles (n = 8) were selected. Using consecutive cryo-sections from a layer containing denticles of different sizes, we examined DMP1, DSP, and DPP in denticle lining cells and tested their co-localizations with the glial stem cell markers nestin, S100β, Sox10, and P0 by quantitative and double staining methods. ResultsDMP1, DSP and DPP were found in odontoblasts, whereas denticle lining cells were positive only for DMP1 and DSP but not for DPP. Nestin was detected in both odontoblasts and denticle lining cells. S100β, Sox10, and P0 were co-localized with DMP1 and DSP in different subpopulations of denticle lining cells. ConclusionsThe co-localization of S100β, Sox10, and P0 with DMP1 and DSP in denticle lining cells suggest that denticle lining cells are originated from glial and/or endoneurial mesenchymal stem cells which are involved in biomineralization of denticle matrix by secretion of DMP1 and DSP. Since denticles are atubular compared to primary, secondary, reactionary tertiary dentin and denticle formed by odontoblasts, our results suggest that DPP could be one of the proteins involved in the complex regulation of dentinal tubule formation.

The role of salivary contents and modern technologies in the remineralization of dental enamel: a narrative review.

Human enamel once formed cannot be biologically repaired or replaced. Saliva has a significant role in remineralization of dental enamel. It not only has a buffering capacity to neutralize the oral cavity's low pH generated after acidic encounters, but also acts as a carrier of essential ions, such as fluoride, calcium and phosphate, which have a positive role in enamel's remineralization. This review discusses how salivary contents, like proteins and enzymes, have a natural role in enamel's mineralization. In addition, the presence of ions, such as fluoride, calcium and phosphate, in saliva further enhances its capability to remineralize the demineralized enamel surface. The review further examines modern innovative technologies, based on biomimetic regeneration systems, including dentin phosphoproteins, aspartate-serine-serine, recombinant porcine amelogenin, leucine-rich amelogenin peptide and nano-hydroxyapatite, that promote enamel remineralization. Fluoride boosters like calcium phosphates, polyphosphates, and certain natural products can also play an important role in enamel remineralization.

DSPP dosage affects tooth development and dentin mineralization.

Dentin Sialoprotein (DSP) and phosphophoryn (PP) are two most dominant non-collagenous proteins in dentin, which are the cleavage products of the DSPP (dentin sialophosphoprotein) precursor protein. The absence of the DSPP gene in DSPP knock-out (KO) mice results in characteristics that are consistent with dentinogenesis imperfecta type III in humans. Symptoms include thin dentin, bigger pulp chamber with frequent pulp exposure as well as abnormal epithelial-mesenchymal interactions, and the appearance of chondrocyte-like cells in dental pulp. To better understand how DSPP influences tooth development and dentin formation, we used a bacterial artificial chromosome transgene construct (BAC-DSPP) that contained the complete DSPP gene and promoter to generate BAC-DSPP transgenic mice directly in a mouse DSPP KO background. Two BAC-DSPP transgenic mouse strains were generated and characterized. DSPP mRNA expression in BAC-DSPP Strain A incisors was similar to that from wild-type (wt) mice. DSPP mRNA expression in BAC-DSPP Strain B animals was only 10% that of wt mice. PP protein content in Strain A incisors was 25% of that found in wt mice, which was sufficient to completely rescue the DSPP KO defect in mineral density, since microCT dentin mineral density analysis in 21-day postnatal animal molars showed essentially identical mineral density in both strain A and wt mice. Strain B mouse incisors, with 5% PP expression, only partially rescued the DSPP KO defect in mineral density, as microCT scans of 21-day postnatal animal molars indicated a reduced dentin mineral density compared to wt mice, though the mineral density was still increased over that of DSPP KO. Furthermore, our findings showed that DSPP dosage in Strain A was sufficient to rescue the DSPP KO defect in terms of epithelial-mesenchymal interactions, odontoblast lineage maintenance, along with normal dentin thickness and normal mineral density while DSPP gene dosage in Strain B only partially rescued the aforementioned DSPP KO defect.

Tissue-specific biomarkers in gingival crevicular fluid are correlated with external root resorption caused by constant mechanical load: an in vivo study.

This study investigated the association of changes in cementum protein-1 (CEMP-1), dentine phosphoprotein (DPP), and c-terminal cross-linked telopeptide of type I collagen (CTX-I) levels in human gingival crevicular fluid (GCF) under constant load with external root resorption volume and amount of tooth movement. In total, 11 healthy adult patients (mean age, 23.5 years [range, 18.3-37.7]; four men and seven women) were enrolled. GCF samples were obtained from premolars at T0, T1 (1 day), T2 (1 week), T3 (2 weeks), T4 (4 weeks), and T5 (8 weeks) under constant 100-gm buccal tipping force. Opposite premolars were used as controls. Teeth were extracted at T5, followed by quantification of external root resorption volume and histological analysis. In the test group, T5/T0 ratios of CEMP-1 and DPP levels, differential CEMP-1 levels between T5 and T0, and differential DPP levels between T2 and T0 correlated positively with root resorption volume (r = 0.734, 0.730, 0.627, and 0.612, respectively, all p < 0.05). CEMP-1 levels at T0 and T3 correlated negatively with root resorption volume (r = -0.603 and -0.706; all p < 0.05). CTX-I levels at T5 correlated positively with the amount of tooth movement (r = 0.848, p < 0.01). Alterations in CEMP-1 and DPP levels in human GCF at specific timepoints during orthodontic treatment may be associated with different degrees of external root resorption. This study demonstrates that changes in the levels of tissue-specific biomarkers in GCF may facilitate early detection of external root resorption during orthodontic tooth movement.

The miR-155-5p inhibits osteoclast differentiation through targeting CXCR2 in orthodontic root resorption.

Root resorption is an unavoidable side effect of orthodontic tooth movement. The mechanism of root resorption is similar to bone resorption; the odontoclasts share similar characteristics with osteoclasts (OCs). MicroRNAs (miRNAs) such as miR-155-5p play an important role in OC differentiation, but the underlying molecular mechanism of miR-155-5p in this process is not fully understood. We found that the miR-155-5p seed sequences were complementary to a sequence conserved in the 3-untranslated region of CXCR2 mRNA. In this study, we explored the molecular mechanism underlying the effect of miR-155-5p on OC differentiation by targeting CXCR2. In this study, we divided the orthodontic patients into mild, moderate, and severe groups according to the severity of root resorption. The gingival crevicular fluid (GCF) of patients in different groups was collected, and the expression levels of dentin phosphoprotein (DPP) were detected by ELISA, and the expression levels of CXCR2 and miR-155-5p in GCF were detected by real-time quantitative PCR (qRT-PCR). The relationship between miR-155-5p and CXCR2 was verified by double luciferase. We analyzed changes of CXCR2 and miR-155-5p expression after transfection of miR-155-5p mimic and inhibitor into RAW264.7 cells induced by receptor activator of nuclear factor-κB ligand (RANKL) through qRT-PCR and western blotting. The effect of miR-155-5p on OC differentiation was evaluated by tartrate-resistant acid phosphatase (TRAP) staining. QRT-PCR and western blotting were used to analyze expression of the osteoclastic bone resorption-related enzymes carbonic anhydrase 2 (CA II), matrix metalloproteinase-9 (MMP-9), and cathepsin K. To further confirm the direct targeting effect of CXCR2 by miR-155-5p, we blocked CXCR2 using si-CXCR2 in RANKL-induced RAW264.7 cells. Dentin phosphoprotein levels were consistent with the trend of miR-155-5p changes, and the trend of CXCR2 expression was opposite to miR-155-5p changes. miR-155-5p can be directly targeted to act on CXCR2. The expression of miR-155-5p was significantly downregulated in differentiated OCs. MiR-155-5p inhibited OC differentiation, and downregulated CA II, MMP-9, and cathepsin K expression at the protein and mRNA levels. In summary, the results of this study suggested that miR-155-5p inhibited OC differentiation by targeting CXCR2, thus reducing root resorption in orthodontics. MiR-155-5p can be used as an effective target for avoiding or reducing the degree of root resorption in orthodontic treatment.

Fluoride Alters Signaling Pathways Associated with the Initiation of Dentin Mineralization in Enamel Fluorosis Susceptible Mice.

Fluoride can alter the formation of mineralized tissues, including enamel, dentin, and bone. Dentin fluorosis occurs in tandem with enamel fluorosis. However, the pathogenesis of dentin fluorosis and its mechanisms are poorly understood. In this study, we report the effects of fluoride on the initiation of dentin matrix formation and odontoblast function. Mice from two enamel fluorosis susceptible strains (A/J and C57BL/6J) were given either 0 or 50ppm fluoride in drinking water for 4weeks. In both mouse strains, there was no overall change in dentin thickness, but fluoride treatment resulted in a significant increase in the thickness of the predentin layer. The lightly mineralized layer (LL), which lies at the border between predentin and fully mineralized dentin and is associated with dentin phosphoprotein (DPP), was absent in fluoride exposed mice. Consistent with a possible reduction of DPP, fluoride-treated mice showed reduced immunostaining for dentin sialoprotein (DSP). Fluoride reduced RUNX2, the transcription regulator of dentin sialophosphoprotein (DSPP), that is cleaved to form both DPP and DSP. In fluoride-treated mouse odontoblasts, the effect of fluoride was further seen in the upstream of RUNX2 as the reduced nuclear translocation of β-catenin and phosphorylated p65/NFκB. In vitro, MD10-F2 pre-odontoblast cells showed inhibition of the Dspp mRNA level in the presence of 10μM fluoride, and qPCR analysis showed a significantly downregulated level of mRNAs for RUNX2, β-catenin, and Wnt10b. These findings indicate that in mice, systemic exposure to excess fluoride resulted in reduced Wnt/β-catenin signaling in differentiating odontoblasts to downregulate DSPP production via RUNX2.

The role of salivary contents and modern technologies in the remineralization of dental enamel: a narrative review

Human enamel once formed cannot be biologically repaired or replaced. Saliva has a significant role in remineralization of dental enamel. It not only has a buffering capacity to neutralize the oral cavity's low pH generated after acidic encounters, but also acts as a carrier of essential ions, such as fluoride, calcium and phosphate, which have a positive role in enamel's remineralization. This review discusses how salivary contents, like proteins and enzymes, have a natural role in enamel's mineralization. In addition, the presence of ions, such as fluoride, calcium and phosphate, in saliva further enhances its capability to remineralize the demineralized enamel surface. The review further examines modern innovative technologies, based on biomimetic regeneration systems, including dentin phosphoproteins, aspartate-serine-serine, recombinant porcine amelogenin, leucine-rich amelogenin peptide and nano-hydroxyapatite, that promote enamel remineralization. Fluoride boosters like calcium phosphates, polyphosphates, and certain natural products can also play an important role in enamel remineralization.

Mineralization of calcium phosphate controlled by biomimetic self-assembled peptide monolayers via surface electrostatic potentials

The functions of acidic-rich domains in non-collagenous protein during biomineralization are thought to induce nucleation and control the growth of hydroxyapatite. The tripeptide Asp-Ser-Ser (DSS) repeats are the most common acidic-rich repeated unit in non-collagenous protein of dentin phosphoprotein, the functions of which have aroused extensive interests. In this study, biomimetic peptides (DSS)n (n = 2 or 3) were designed and fabricated into self-assembled monolayers (SAMs) on Au (111) surface as biomimetic organic templates to regulate hydroxyapatite (HAp) mineralization in 1.5 simulated body fluid (1.5 SBF) at 37 °C. The early mineralization processes and minerals deposited on the SAMs were characterized by X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy analyses. The SAM-DSS9/DSS9G showed the highest capacity to induce HAp nucleation and growth, followed by SAM-DSS6/DSS6G, SAM-COOH, and SAM-OH. The SAM-(DSS)n had more negative zeta potentials than SAM-COOH surface, indicating that DSS repeats contributed to the biomineralization, which not only provided strong affinity with Ca2+ ions through direct electrostatic bonds, but more importantly influence surface electrostatic potentials of the assembled organic template for nucleation.

The role of salivary contents and modern technologies in the remineralization of dental enamel: a review

Human enamel once formed cannot be biologically repaired or replaced. Saliva has a significant role in remineralization of dental enamel. It not only has a buffering capacity to neutralize the oral cavity’s low pH generated after acidic encounters, but also acts as a carrier of essential ions, such as fluoride, calcium and phosphate, which have a positive role in enamel’s remineralization. This review discusses how salivary contents, like proteins and enzymes, have a natural role in enamel’s mineralization. In addition, the presence of ions, such as fluoride, calcium and phosphate, in saliva further enhances its capability to remineralize the demineralized enamel surface. The review further examines modern innovative technologies, based on biomimetic regeneration systems, including dentin phosphoproteins, aspartate-serine-serine, recombinant porcine amelogenin, leucine-rich amelogenin peptide and nano-hydroxyapatite, that promote enamel remineralization. Fluoride boosters like calcium phosphates, polyphosphates, and certain natural products can also play an important role in enamel remineralization.

The composite sandwich structure of dNCPs polyelectrolyte multilayers induced the osteogenic differentiation of PDLSCs in vitro.

This study reported about the fabrication of dentin non-collagenous proteins (dNCPs) polyelectrolyte multilayers and evaluated its osteogenic potential. The composite sandwich structure of dNCPs polyelectrolyte multilayers was generated on the surface of polycaprolactone electrospinning membranes by the Layer-by-Layer self-assembly technique. The dNCPs-coated membranes comprised the experimental group and the non-coated membranes acted as the control. Nanofiber morphologies of both membranes were observed under scanning electron microscope. The release of dNCPs was evaluated by ELISA kit. Periodontal ligament stem cells (PDLSCs) were seeded on both membranes. The morphology changes and proliferation of cells were tested. The expressions of osteogenic-related genes and proteins were evaluated by RT-PCR, alkaline phosphatase (ALP) activity assay, and immunofluorescence staining. dNCPs-coated membranes displayed significantly different fiber morphology than the non-coated membranes. A stable release of dentin phosphoprotein was maintained from day 4 to day 15 in the experimental group. Cells on dNCPs-coated membranes were found to have cuboidal or polygonal shapes. The proliferative rate of cells was significantly lower in the experimental group from day 4 to day 9 (p<0.05). However, cells on the dNCPs-coated membranes demonstrated a significantly higher ALP content and expression levels of osteogenic gene and proteins than the controls (p<0.05). These results indicated that dNCPs polyelectrolyte multilayers could induce the osteogenic differentiation of PDLSCs in vitro.

Dentin phosphoprotein inhibits lipopolysaccharide-induced macrophage activation independent of its serine/aspartic acid-rich repeats

ObjectiveThe objective of this study was to investigate the effects of dentin phosphoprotein (DPP) on lipopolysaccharide-induced inflammatory responses of macrophages in vitro. DesignWildtype and mutant recombinant dentin phosphoprotein (rDPP) proteins were generated using a mammalian expression system. Macrophages, phorbol 12-myristate 13-acetate-differentiated THP-1 cells, were stimulated with lipopolysaccharide in the absence or presence of rDPP proteins. After the 24-hr incubation, the inflammatory gene expression levels were examined by quantitative reverse-transcription polymerase chain reaction and the amount of secreted TNF-α protein was evaluated by enzyme-linked immunosorbent assay. Furthermore, the subcellular localization of exogenously added rDPP was examined by immunocytochemistry, and the direct binding of rDPP to lipopolysaccharide was quantified by solid-phase binding assay. ResultsrDPP dose-dependently reduced the expression of lipopolysaccharide-induced inflammatory genes, such as TNFα, IL-1β, and IL-8, and TNF-α protein secretion from the macrophages. Furthermore, mutant rDPP having a shortened serine/aspartic acid-rich repeats (SDrr) was also able to inhibit lipopolysaccharide-induced inflammatory responses of macrophages. rDPP was localized adjacent to the cellular membrane rather than in the cytoplasm, and rDPP was able to bind to lipopolysaccharide. These results suggested that rDPP inhibited lipopolysaccharide-induced inflammatory responses by binding to lipopolysaccharide. ConclusionsIn addition to the well-known functions of DPP for dentin mineralization that depend on the SDrr, we demonstrated that DPP possesses anti-inflammatory effects on lipopolysaccharide-stimulated macrophages that are independent of the SDrr.

Biomarkers in the gingival crevicular fluid used to detect root resorption in patients undergoing orthodontic treatment: A systematic review.

To evaluate whether changes in the concentration of different biomarkers in the gingival crevicular fluid (GCF) can be used to detect the root resorption process in adult or adolescent patients undergoing treatment with a fixed appliance, in comparison with untreated subjects or treated patients not showing signs of root resorption. The following databases were analysed in the period between June 2017 and March 2018, without any language and initial date restrictions: PubMed, EMBASE, Scopus, Web of Science and Cochrane Library. A quality assessment instrument (QAI) was developed to establish the risk of bias. A total of 1127 articles were analysed. Based on the inclusion and exclusion criteria, seven studies qualified for the final review. The QAI tool revealed that five articles were at a moderate risk of bias and two articles were at a low risk of bias. Dentine phosphoprotein (DPP) may be considered a relatively useful marker for root resorption. Dentinal sialoprotein (DSP) could be a potential biomarker but is not highly helpful at detecting root shortening. Inflammatory cytokines (pro- and anti-resorption), osteopontin (OPN), osteoprotegerin (OPG), RANKL and alkaline phosphatase (ALP) are useful biomarkers to explain the biological mechanisms that occur during orthodontic movement but are not specific enough. Further studies are required to clarify the role of GM-CSF as a potential biomarker to distinguish subjects at a risk of severe root resorption in the early phase.