USP12 regulates ER stress-associated osteogenesis in human periodontal ligament cells under tension stress.

The bone formation (osteogenesis) of human periodontal ligament cells (hPDLCs) under tension stress is essential for alveolar bone remodeling during orthodontic tooth movement (OTM). Deubiquitinating enzymes (DUBs) remove ubiquitin from target proteins, affecting their function and mediating cell survival and differentiation. However, whether and how DUBs regulate hPDLC function under tension force is poorly understood. In this study, we first investigated the expression of DUBs in hPDLCs under cyclic tension stimulation (CTS). Up-regulation of USP12 was observed in hPDLCs and at the tension side of molar teeth in OTM C57BL6 mice models. Knockdown (KD) of USP12 led to enhanced osteogenesis of hPDLCs under CTS. RNA-seq analysis suggested that the unfolded protein response (UPR) was the prevailing biological process in hPDLCs with USP12 KD, indicating that USP12 depletion triggered endoplasmic reticulum (ER) stress. The three major UPR-related signaling branches, namely PERK/eIF2α/ATF4, IRE1α/XBP1s, and ATF6 axis, were activated in hPDLCs with USP12 KD. By utilizing specific inhibitors, we proved that the PERK/eIF2α/ATF4 axis predominantly mediated the enhanced osteogenesis in hPDLCs with USP12 KD under CTS. In summary, our study demonstrates that USP12 serves as a key regulator for CTS-induced osteogenesis in hPDLCs, suggesting that USP12 upregulation serves as an adaptive mechanism for hPDLCs to alleviate ER stress during OTM.

YAP/WNT5A/FZD4 axis regulates osteogenic differentiation of human periodontal ligament cells under cyclic stretch.

OBJECTIVE: To verify the role of YAP/WNT5A/FZD4 axis in stretch-induced osteogenic differentiation of hPDLCs. BACKGROUND: During orthodontic tooth movement, differentiation of human periodontal ligament cells (hPDLCs) at the tension side of the periodontal ligament mediates new bone formation. WNT5A promotes osteogenesis and its regulator Yes-associated protein (YAP) is responsive to mechanical stimulation in hPDLCs. However, the mechanisms of YAP and WNT5A in alveolar bone remodeling remain unclear. METHODS: Cyclic stretch was applied to hPDLCs to mimic the orthodontic stretching force. Osteogenic differentiation was determined by alkaline phosphatase (ALP) activity, Alizarin Red staining, qRT-PCR and western blotting. To detect activation of YAP and expression of WNT5A and its receptor Frizzled-4 (FZD4), western blotting, immunofluorescence, qRT-PCR and ELISA were performed. Verteporfin, Lats-IN-1, small interfering RNAs and recombinant protein were used to explore the relationship of YAP, WNT5A and FZD4, and the effect of their relationship on stretch-induced osteogenesis of hPDLCs. RESULTS: WNT5A, FZD4 and nuclear localization of YAP were upregulated by cyclic stretch. YAP positively regulated WNT5A and FZD4 expression and osteogenic differentiation of hPDLCs under cyclic stretch by YAP inhibition or activation assay. Knockdown of WNT5A and FZD4 attenuated YAP-induced and stretch-induced osteogenic differentiation. Recombinant WNT5A rescued the suppressed osteogenic differentiation by YAP inhibitor in hPDLCs, whereas knockdown of FZD4 weakened the effect of WNT5A and amplified the suppression. CONCLUSIONS: WNT5A/FZD4 could be positively regulated by YAP and the YAP/WNT5A/FZD4 axis mediated osteogenic differentiation of hPDLCs under cyclic stretch. This study provided further insight into the biological mechanism of orthodontic tooth movement.

Characteristics of a novel temperate bacteriophage against Staphylococcus arlettae (vB_SarS_BM31) / Características de un nuevo bacteriófago templado contra Staphylococcus arlettae (vB_SarS_BM31)

Background: Staphylococcus arlettae is a rarely reported coagulase-negative staphylococcus (CoNS) isolated from infected humans and livestock. Observing phage-bacteria interaction could improve the understanding of bacterial pathogenetic mechanisms, providing foundational evidence for phage therapy or phage detection. Herein, we aimed to characterise and annotate a novel bacteriophage, vB_SarS_BM31 (BM31), specific to S. arlettae. This bacteriophage was isolated from a milk sample associated with bovine mastitis and collected in the Sichuan Province, China. Results: The BM31 genome comprised a linear double-stranded DNA of 42,271 base pair in length with a G + C content of 34.59%. A total of 65 open reading frames (ORFs) were assembled from phage DNA, of which 29 were functionally annotated. These functional genes were divided into four modules: the structural, DNA packing and replication, lysis, and lysogeny modules. Holin (ORF25), lysin (ORF26), and integrase (ORF28) were located closely in the entire BM31 genome and were important for lyse or lysogeny cycle of BM31. The phage was identified as a temperate phage according to whole genome analysis and life cycle assay, with basic biological characteristics such as small burst size, short latency period, and narrow host range, consistent with the characteristics of the family Siphoviridae, subcluster B14 of the Staphylococcus bacteriophage. Conclusions: The present isolation and characterisation of BM31 contributes to the Staphylococcus bacteriophage database and provides a theoretical foundation for its potential applications. To the best of our knowledge, BM31 is the only shared and completely reported phage against S. arlettae in the entire public database.(AU)

Exosomes from Tension Force-Applied Periodontal Ligament Cells Promote Mesenchymal Stem Cell Recruitment by Altering microRNA Profiles.

Background and Objectives: To investigate the role of exosomes from periodontal ligament cells (PDLCs) in bone marrow mesenchymal stem cell (BMSC) migration. Methods and Results: Human PDLCs were applied cyclic tension stretching. Exosomes were extracted from cultured PDLCs by ultracentrifugation, then characterized for their size, morphology and protein markers by NTA, TEM and western blotting. The process that PKH26-labeled exosomes taken up by BMSCs was assessed by confocal microscope. BMSC migration was examined by Transwell assay. Exosomes derived from PDLCs were identified. Cyclic tension stretch application on PDLCs can enhance the migration ability of BMSCs through exosomes. The exosomal miRNA expression profiles of unstretched and stretched PDLCs were tested by miRNA microarray. Four miRNAs (miR-4633-5p, miR-30c-5p, miR-371a-3p and let-7b-3p) were upregulated and six (miR-4689, miR-8485, miR-4655-3p, miR-4672, miR-3180-5p and miR-4476) were downregulated in the exosomes after stretching. Sixteen hub proteins were found in the miRNA-mRNA network. Gene Ontology and KEGG pathway analyses demonstrated that the target genes of differentially expressed exosomal miRNAs closely related to the PI3K pathway and vesicle transmission. Conclusions: The exosomes derived from cyclic tension-stretched PDLCs can promote the migration of BMSCs. Alternation of microRNA profiles provides a basis for further research on the regulatory function of the exosomal miRNAs of PDLCs during orthodontic tooth movement.

Characteristics of a novel temperate bacteriophage against Staphylococcus arlettae (vB_SarS_BM31).

BACKGROUND: Staphylococcus arlettae is a rarely reported coagulase-negative staphylococcus (CoNS) isolated from infected humans and livestock. Observing phage-bacteria interaction could improve the understanding of bacterial pathogenetic mechanisms, providing foundational evidence for phage therapy or phage detection. Herein, we aimed to characterise and annotate a novel bacteriophage, vB_SarS_BM31 (BM31), specific to S. arlettae. This bacteriophage was isolated from a milk sample associated with bovine mastitis and collected in the Sichuan Province, China. RESULTS: The BM31 genome comprised a linear double-stranded DNA of 42,271 base pair in length with a G + C content of 34.59%. A total of 65 open reading frames (ORFs) were assembled from phage DNA, of which 29 were functionally annotated. These functional genes were divided into four modules: the structural, DNA packing and replication, lysis, and lysogeny modules. Holin (ORF25), lysin (ORF26), and integrase (ORF28) were located closely in the entire BM31 genome and were important for lyse or lysogeny cycle of BM31. The phage was identified as a temperate phage according to whole genome analysis and life cycle assay, with basic biological characteristics such as small burst size, short latency period, and narrow host range, consistent with the characteristics of the family Siphoviridae, subcluster B14 of the Staphylococcus bacteriophage. CONCLUSIONS: The present isolation and characterisation of BM31 contributes to the Staphylococcus bacteriophage database and provides a theoretical foundation for its potential applications. To the best of our knowledge, BM31 is the only shared and completely reported phage against S. arlettae in the entire public database.

Molecular typing and prevalence of antibiotic resistance and virulence genes in Streptococcus agalactiae isolated from Chinese dairy cows with clinical mastitis.

Bovine mastitis is a common disease occurring in dairy farms and can be caused by more than 150 species of pathogenic bacteria. One of the most common causative organisms is Streptococcus agalactiae, which is also potentially harmful to humans and aquatic animals. At present, research on S. agalactiae in China is mostly concentrated in the northern region, with limited research in the southeastern and southwestern regions. In this study, a total of 313 clinical mastitis samples from large-scale dairy farms in five regions of Sichuan were collected for isolation of S. agalactiae. The epidemiological distribution of S. agalactiae was inferred by serotyping isolates with multiplex polymerase chain reaction. Susceptibility testing and drug resistance genes were detected to guide the clinical use of antibiotics. Virulence genes were also detected to deduce the pathogenicity of S. agalactiae in Sichuan Province. One hundred and five strains of S. agalactiae (33.6%) were isolated according to phenotypic features, biochemical characteristics, and 16S rRNA sequencing. Serotype multiplex polymerase chain reaction analysis showed that all isolates were of type Ia. The isolates were up to 100% sensitive to aminoglycosides (kanamycin, gentamicin, neomycin, and tobramycin), and the resistance rate to ß-lactams (penicillin, amoxicillin, ceftazidime, and piperacillin) was up to 98.1%. The TEM gene (ß-lactam-resistant) was detected in all isolates, which was in accordance with a drug-resistant phenotype. Analysis of virulence genes showed that all isolates harbored the cfb, cylE, fbsA, fbsB, hylB, and α-enolase genes and none harbored bac or lmb. These data could aid in the prevention and control of mastitis and improve our understanding of epidemiological trends in dairy cows infected with S. agalactiae in Sichuan Province.

Isolation of Klebsiella pneumoniae Phage vB_KpnS_MK54 and Pathological Assessment of Endolysin in the Treatment of Pneumonia Mice Model.

With the improper use of antibiotics, an increasing number of multidrug-resistant bacteria have been reported worldwide, posing challenges for disease treatment. Klebsiella pneumoniae is an important zoonotic pathogen that colonises the respiratory tract. Endolysin therapy has emerged with the development of phages. In this study, a lytic phage vB_KpnS_MK54 was isolated from the drinking water of a forest musk deer (FMD) farm in Sichuan Province. It was the first reported phage obtained from FMD. The primary biological characteristics were determined, and whole-genome sequencing analysis was performed. The phage which belongs to the family Siphoviridae is highly specific for lytic host bacteria and is moderately adaptable to different environments. Whole-genome sequencing results showed that the phage genome size was 46,218 bp. There were 80 coding DNA sequences (CDSs) in total, 32 of which had known functions. The last CDS is the phage endolysin LysG24. A new peptide-modified endolysin (LysCA) was constituted by connecting the cecropin A peptide residues with LysG24 to investigate the antibacterial activities of both LysG24 and LysCA. The results showed that the lytic profile of LysG24 and LysCA was wider than that of phage MK54. For in vitro tests, both endolysins destroyed 99% of the host bacteria within 6 h. The lysing ability and environmental adaptability of LysCA were significantly stronger than those of LysG24. For in vivo tests, LysG24 and LysCA exhibited therapeutic effects in a mouse model of pneumonia wherewith the mice were infected with K. pneumoniae (LPKP), wherein both LysG24 and LysCA can effectively reduce the pulmonary inflammatory response. The LPKP bacterial load in the treatment group was significantly lower than that in the bacterial group, among which LysCA displayed a more obvious therapeutic effect. Furthermore, the safety test showed that the endolysins had no toxic effects on mice. In general, both LysG24 and LysCA showed excellent antibacterial activity in vivo and in vitro, with high safety and strong adaptability to the environment, manifesting their latent potential as new antimicrobial agents.

Isolation, Genomic Analysis, and Preliminary Application of a Bovine Klebsiella pneumoniae Bacteriophage vB_Kpn_B01.

Klebsiella pneumoniae is an important pathogen that can infect both humans and cattle. The widespread K. pneumoniae and its high drug resistance make it difficult to treat Klebsiella infections/diseases. In this study, a lytic K. pneumoniae bacteriophage vB_Kpn_B01 was isolated from a dairy farm trough in Sichuan Province, and its biological properties were studied, and the entire genome of vB_Kpn_B01 was sequenced. The therapeutic effects of the phage on disease-causing mice were preliminarily tested. Phages found in this study are double-stranded DNA bacterial viruses belonging to the family Siphoviridae, Sugarlandvirus. The results suggest that vB_Kpn_B01 has strong specificity and low adaptability to different adverse conditions. Meanwhile, the predicted gene products of phage vB_Kpn_B01 comprised 149 coding sequences (CDS) and 25 tRNAs, of which 34 CDS had known functions. Of course, vB_Kpn_B01 did not contain any known antibiotic-resistant or virulent genes. The pathological sections of the liver and lungs of mice showed that the inflammatory scores of the treatment group were lower than in the bacterial group. Phage vB_Kpn_B01 alleviated the inflammatory response in the organs of the infected mice, and the organ tissue bacterial load of the treatment group was significantly lower than that of the bacterial group. Therefore, vB_Kpn_B01 can inhibit the proliferation of K. pneumoniae 18 in vivo and can alleviate the inflammation of target organs caused by infectious bacteria, which preliminarily indicates that vB_Kpn_B01 has a certain therapeutic effect on laboratory-infected mice.

CREB activation affects mesenchymal stem cell migration and differentiation in periodontal tissues due to orthodontic force.

During the orthodontic tooth movement, cells in periodontal ligament could differentiate into osteoblasts to synthesize alveolar bone as well as affect the proliferation, migration and differentiation of mesenchymal stem cells, which also contribute to bone remodeling. However, the mechanism is still largely elusive. Here, we evaluated the expression of CREB at the tension site of mouse periodontal ligament under orthodontic mechanical strain and in the cyclic tension strain treated human periodontal ligament cells. Then, through gain and loss of function analysis, we revealed that CREB in PDLCs promotes SDF-1 and FGF2 secretion, which enhance the migration and osteoblastic differentiation of BMSCs. We further discovered that CREB transcriptionally activates FGF2 and SDF-1 expressions by binding to the promoter regions.In conclusion, this study confirms that CREB is an upregulated gene in periodontal ligament under orthodontic tension strain stimulation and plays an important role in regulating BMSCs' physiological activity in orthodontic tension strain-induced bone formation.

Chitosan/collagen scaffold containing bone morphogenetic protein-7 DNA supports dental pulp stem cell differentiation in vitro and in vivo.

In this study, porous chitosan/collagen scaffolds were prepared through a freeze-drying process, and loaded with the plasmid vector encoding human bone morphogenetic protein-7 (BMP-7) gene. To investigate the feasibility and efficacy of this gene-activated scaffold on dental tissue engineering, human dental pulp stem cells (DPSCs) were seeded in this scaffold for in vitro and in vivo study. In vitro results indicated that cells can be transfected successfully by loaded plasmid and secrete BMP-7 until day 24. Evaluation of DNA content, ALP activity, calcium content, SEM, and real-time PCR revealed that cells on gene-activated scaffold showed better proliferation properties and odontoblastic differentiation behaviors than cells on pure scaffolds. Then, these cell-scaffold complexes were implanted subcutaneously and retrieved after 4 weeks for histology evaluation. In vivo results that gene-activated scaffold group could still trace the existence of tranfected cells at week 4 and showed the upregulated expression of DSPP compared to pure scaffold groups. On the basis of our results, chitosan/collagen-loaded BMP-7 DNA appears to be an effective substrate candidate for gene delivery and indeed enhanced DPSCs differentiation toward an odontoblast-like phenotype in vitro and in vivo. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.

Cyclic Stretch Enhances Osteogenic Differentiation of Human Periodontal Ligament Cells via YAP Activation.

Periodontal remodeling and alveolar bone resorption and formation play essential roles during orthodontic tooth movement (OTM). In the process, human periodontal ligament cells (HPDLCs) sense and respond to orthodontic forces, contributing to the alveolar bone formation. However, the underlying mechanism in this process is not fully elucidated. In the present study, cyclic stress stimulus was applied on HPDLCs to mimic the orthodontic forces during OTM. Our results demonstrated that cyclic stretch promoted the osteogenic differentiation of HPDLCs. Moreover, our data suggested that yes-associated protein (YAP), the Hippo pathway effector, which also involved in mechanical signaling transduction, was activated as we found that the nuclear translocation of YAP was significantly increased in the cyclic stress treated HPDLCs. The mRNA expression of CTGF and CYR61, the target genes of YAP, was also remarkably increased. Furthermore, knockdown of YAP suppressed the cyclic stretch induced osteogenesis in HPDLCs, while overexpression of YAP in HPDLCs enhanced osteogenesis. We also noticed that YAP activities could be suppressed by the ROCK and nonmuscle myosin II inhibitors, Y-27632 and Blebbistatin. The inhibitors also significantly inhibited the cyclic stretch induced osteogenesis in HPDLCs. Finally, in the murine OTM model, our results revealed that YAP was upregulated and nuclearly translocated in the PDLCs at the tension side. In summary, our present study demonstrated that cytoskeleton remodeling induced activation of YAP signaling pathway was crucial for the cyclic stretch-induced osteogenesis of HPDLCs, which might play important roles during OTM.

Cell-borne 2D nanomaterials for efficient cancer targeting and photothermal therapy.

Two of the challenges for clinical implementation of nano-therapeutic strategies are optimization of tumor targeting and clearance of the nanoagents in vivo. Herein, a cell-mediated therapy by transporting 2D Bi2Se3 nanosheets within macrophage vehicles is described. The Bi2Se3 nanosheets with excellent near-infrared photothermal performance exhibit high macrophage uptake and negligible cytotoxicity thus facilitating the fabrication of Bi2Se3-laden-macrophages. Compared with bare Bi2Se3, the Bi2Se3-laden-macrophages after intravenous injection show prolonged blood circulation and can overcome the hypoxia-associated drug delivery barrier to target the tumor efficiently and dramatically enhance the efficiency of photothermal cancer therapy. The Bi2Se3-laden-macrophages possess good biocompatibility as demonstrated by the biochemical and histological analyses and furthermore, most of the materials are excreted from the body within 25 days. Our findings reveal a desirable system for highly efficient near-infrared photothermal cancer therapy.

MicroRNA-195-5p Regulates Osteogenic Differentiation of Periodontal Ligament Cells Under Mechanical Loading.

Osteogenic differentiation and bone formation are tightly regulated by several factors, including microRNAs (miRNAs). However, miRNA expression patterns and function during mechanical loading-induced osteogenic differentiation of human periodontal ligament cells (PDLCs) remain unclear. Here, we investigated the differential expression of miRNA-195-5p in the periodontal tissues of mice under orthodontic mechanical loading and in primary human PDLCs exposed to a simulated tension strain. The miR-195-5p was observed to be down-regulated and negatively correlated with osteogenic differentiation. Overexpression of miR-195-5p significantly inhibited PDLC differentiation under cyclic tension strain (CTS), whereas the functional inhibition of miR-195-5p yielded an opposite effect. Further experiments confirmed that WNT family member 3A (WNT3A), fibroblast growth factor 2 (FGF2), and bone morphogenetic protein receptor-1A (BMPR1A), proteins important for osteogenic activity and stability, were direct targets of miR-195-5p. Mechanical loading increased the WNT3A, FGF2, and BMPR1A protein levels, while miR-195-5p inhibited WNT3A, FGF2, and BMPR1A protein expression. WNT, FGF, and BMP signaling were involved in osteogenic differentiation of PDLCs under CTS. Further study confirmed that reintroduction of WNT3A and BMPR1A can rescue the inhibition of miR-195-5p on osteogenic differentiation of PDLCs. Our findings are the first to demonstrate that miR-195-5p is a mechanosensitive gene that plays an important role in mechanical loading-induced osteogenic differentiation and bone formation.

Wnt5a mediated canonical Wnt signaling pathway activation in orthodontic tooth movement: possible role in the tension force-induced bone formation.

Orthodontic tooth movement (OTM) is associated with bone remodeling mediated by orthodontic mechanical loading. Increasing studies reported that Wnt signaling played crucial roles in mechanical stimuli induced bone remodeling. However, little is known about the involvement of Wnt signaling in orthodontic force-induced bone formation during OTM. In virtue of the OTM mice model as we previously reported, where new bone formation was determined by micro-CT and immunoreactivity of osteocalcin and osterix, we explored the activation of Wnt signaling pathway during OTM. Our results proved the nuclei translocation of ß-catenin, suggesting the activation of canonical Wnt signaling pathway in the periodontal ligament cells (PDLCs) near the alveolar bone at the tension site (TS). Moreover, the immunoreactivity of Wnt5a, but not Wnt3a in PDLCs indicated the activation of canonical Wnt pathway might be mediated by Wnt5a, but not Wnt3a as in most cases. The co-location of Wnt5a and ß-catenin that was evidenced by double labeling immunofluorescence staining further supported the hypothesis. In addition, the high expression of FZD4 and LRP5 in PDLCs at TS of periodontium suggested that the activation of Wnt signaling pathway was mediated by these receptors. The negligible expression of ROR2 also indicated that canonical but not non-canonical Wnt signaling pathway was activated by Wnt5a, since previous studies demonstrated that the activation of canonical/non-canonical Wnt signaling pathway was largely dependent on the receptors. In summary, we here reported that Wnt5a mediated activation of canonical Wnt signaling pathway might contribute to the orthodontic force induced bone remodeling.

Correlation Between Cephalometric Measures and End-of-Treatment Facial Attractiveness.

Sixty-nine experienced Chinese orthodontists evaluated 108 Chinese patients' facial attractiveness from set of photographs (frontal, lateral, and frontal smiling photos) taken at the end of orthodontic treatment. These 108 patients, which contained an equal number of patients with Class I, II, and III malocclusion, were randomly selected from 6 orthodontic treatment centers throughout China. Spearman rank-order correlation coefficients (rs) analyses were performed to examine agreement in ranking between all judge pairs. Pearson correlation and multivariate regression were performed to examine the correlation between cephalometric measures and end-of-treatment Photo Attractiveness Rank.96.68% judge pairs showed moderate correlated (+0.4 ≤ rs < +0.7) subjective rankings. Cephalometric measures significantly correlated with end-of-treatment Photo Attractiveness Rank included interincisal angle (r = 0.330, P < 0.05), L1/MP° (r = 0.386, P < 0.05), L1-NBmm (r = 0.451, P < 0.01), L1/NB° (r = 0.374, P < 0.05), and profile angle (r = 0.353, P < 0.05) in Class I patients with an explained variance of 32.8%, and ANB angle (r = 0.432, P < 0.01), angle of convexity (r = 0.448, P < 0.01), profile angle (r = 0.488, P < 0.01), Li to E-line (r = 0.374, P < 0.05), Li to B-line (r = 0.543, P < 0.01), and Z angle (r = 0.543, P < 0.01) in Class II patient with an explained variance of 43.3%.There was less association than expected between objective measurements on the lateral cephalograms and clinicians' rankings of facial attractiveness on clinical photography in Chinese patients. Straight-stand lower incisor was desired for facial attractiveness of Class I malocclusion; and sagittal relationship and lip prominence influence the esthetics of Class II malocclusion in Chinese population.

Integrated miRNA and mRNA expression profiling of tension force-induced bone formation in periodontal ligament cells.

Tension force-induced bone formation is a complex biological process altered by various factors, for example miRNAs and gene regulatory network. However, we know little about critical gene regulators and their functional consequences on this complex process. The aim of this study was to determine the integrated relation between microRNA and mRNA expression in tension force-induced bone formation in periodontal ligament cells by a system biological approach. We identified 818 mRNAs and 32 miRNAs differentially expressed between cyclic tension force-stimulated human periodontal ligament cells and control cells by microarrays. By using miRNA/mRNA network analysis, protein-protein interactions network analysis, and hub analysis, we found that miR-195-5p, miR-424-5p, miR-1297, miR-3607-5p, miR-145-5p, miR-4328, and miR-224-5p were core microRNAs of tension force-induced bone formation. WDR33, HSPH1, ERBB3, RIF1, IKBKB, CREB1, FGF2, and PAG1 were identified as hubs of the PPI network, suggesting the biological significance in this process. The miRNA expression was further examined in human PDLC and animal samples by using quantitative real-time PCR. Thus, we proposed a model of tension force-induced bone formation which is co-regulated through integration of the miRNA and mRNA. This study illustrated the benefits of system biological approaches in the analysis of tension force-induced bone formation as a complex biological process. We used public information and our experimental data to do comprehensive analysis and revealed the coordination transcriptional control of miRNAs of tension force-induced bone formation.

Correction of a dental arch-width asymmetric discrepancy with a slow maxillary contraction appliance.

A boy, aged 12 years 3 months, sought treatment for a complete unilateral Brodie bite. His maxillary dental arch was asymmetric, and his dentition was 10 mm wider than normal values for his age. The transverse discrepancy was his chief complaint because it caused a chewing dysfunction. We used a special slow maxillary contraction appliance, which contains a screw, connectors, and retainers, to contract the maxillary transverse asymmetric dental arch. This was followed by preadjusted fixed appliances to level the teeth and adjust the occlusion. A symmetric and functional Class I occlusion was achieved.

The effects of gradually induced backward movement of the mandible by a Twin Inclined Plane Device in rats.

OBJECTIVE: To develop a model of gradually induced backward movement of the mandible under normal masticatory action and to examine morphological changes in the mandible and condylar cartilage in rats. MATERIALS AND METHODS: The newly developed Twin Inclined Plane Device (TIPD) was composed of upper and lower posterior metal crowns with a long inclined plane on both sides separately and was applied in experimental groups of 6-week-old male Wister rats. After 3, 14, 30, and 60 days, the rats were euthanatized and samples were collected. Various measurements and hematoxylin-and-eosin stains were performed. RESULTS: From day 30 on, the length of the condylar process was shorter in the TIPD groups than in the control groups (P < .05). The angulation of the condylar process axis to the mandibular plane was greater in the TIPD groups (P < .01). The thickness of the condylar cartilage in the posterior part of the posterior region was thinner in the TIPD groups (P < .05) on day 30 and even thinner (P < .01) on day 60; from day 30 on, the thickness in the anterior part of the posterior region was thicker in the TIPD groups (P < .01). CONCLUSION: TIPD can successfully induce backward movement of the mandible under normal masticatory action. TIPD can cause region-specific changes in condylar cartilage and leads to a continuous remodeling.

Use of onplants as stable anchorage for facemask treatment: a case report.

A hexagonal onplant of 7.7 mm diameter was placed on the palatal bone of the maxilla in an 1-year five-month-old female patient with a Class III malocclusion and midface deficiency. Elastic traction (400 g per side) was applied from a facemask to the onplant at 30 degrees to the occlusal plane 12 hours per day for 12 months. The maxilla was found to have displaced forward and downward by 2.9 mm. The mandible was rotated downward and backward. There was a 3 degrees increase in mandibular plane angle and an increase in the lower face height. Clinically, there was a significant improvement in midface esthetics, noted by an increase in fullness of the infraorbital region and correction of the skeletal discrepancy between the maxillary and mandibular jaw relationship. Contrary to the reports that use teeth rather than onplants as anchorage, there was no forward movement of the maxillary molars and minimal extrusion of the maxillary molars. These results suggest that onplants can be used as an extremely stable anchorage for maxillary orthopedic facemask treatment.

Root resorption after orthodontic intrusion and extrusion: an intraindividual study.

The aim of this investigation was to compare root resorption in the same individual after application of continuous intrusive and extrusive forces. In nine patients (mean age 15.3 years), the maxillary first premolars were randomly intruded or extruded with a continuous force of 100 cN for eight weeks. Eleven maxillary first premolars from six randomly selected orthodontic patients served as controls. Root resorption was determined using scanning electron microscopy. Quantitative assessment of the percentage of resorbed area of the total root surface was performed on composite micrographs. The severity of root resorption was also assessed by visual scoring of the roots. Root resorption mainly occurred at the apical part of the roots in both experimental groups. A significant difference in root resorption was found between the intruded and the control teeth (P = .006) but not between the extruded and the control teeth. However, the mesial and distal root surfaces showed resorption on 5.78 +/- 3.86% of the root surface of the intruded teeth and 1.28 +/- 1.24% of the root surface of the extruded teeth, and this difference was significant (P = .004). In addition, a large individual variation was found. From this study, it can be concluded that intrusion of teeth causes about four times more root resorption than extrusion. Because the amount of root resorption due to intrusion or extrusion in the same patient is correlated, every clinician should be aware that the extrusion of teeth might also cause root resorption in susceptible patients.