Pediatric sleep-disordered breathing in Shanghai: characteristics, independent risk factors and its association with malocclusion.

OBJECTIVES: This study aimed to determine the prevalence and independent risk factors of SDB, and explore its association with malocclusion among 6-11-year-old children in Shanghai, China. METHODS: A cluster sampling procedure was adopted in this cross-sectional study. Pediatric Sleep Questionnaire (PSQ) was applied to evaluate the presence of SDB. Questionnaires including PSQ, medical history, family history, and daily habits/environment were completed by parents under instruction, and oral examinations were implemented by well-trained orthodontists. Multivariable logistic regression was applied to identify independent risk factors for SDB. Chi-square tests and Spearman's Rank Correlation were used to estimate the relationship between SDB and malocclusion. RESULTS: A total of 3433 subjects (1788 males and 1645 females) were included in the study. The SDB prevalence was about 17.7%. Allergic rhinitis (OR 1.39, 95% CI 1.09-1.79), adenotonsillar hypertrophy (OR 2.39, 95% CI 1.82-3.19), paternal snoring (OR 1.97, 95% CI 1.53-2.53), and maternal snoring (OR 1.35, 95% CI 1.05-1.73) were independent risk factors for SDB. The SDB prevalence was higher in children with retrusive mandibles than in proper or excessive ones. No significant difference was observed in the correlation between SDB and lateral facial profile, mandible plane angle, constricted dental arch form, the severity of anterior overjet and overbite, degree of crowding and spacing, and the presence of crossbite and open bite. CONCLUSIONS: The prevalence of SDB in primary students in the Chinese urban population was high and highly associated with mandible retrusion. The independent risk factors included Allergic rhinitis, adenotonsillar hypertrophy, paternal snoring, and maternal snoring. More efforts should be made to enhance public education about SDB and related dental-maxillofacial abnormalities.

The Association of Tonsil Hypertrophy with Pediatric Dentofacial Development: Evidence from a Cross-Sectional Study of Young Children in Shanghai, China.

Purpose: The prevalence of dentofacial deformity was reportedly higher than decades ago, to which upper airway (UA) obstruction-induced sleep-disordered breathing (SDB) might contribute a lot. Tonsil hypertrophy appears relatively common in the population of young children. Given that the association between tonsil hypertrophy and pediatric dentofacial deformity remained controversial, this cross-sectional research was designed to explore the internal relationship of those among young children in Shanghai, China. Patients and Methods: A stratified cluster sampling procedure was adopted, and a representative sample of 715 young children (8-10 years old) was recruited. The OSA-18 quality-of-life questionnaires (OSA-18) were finished by their guardians, and well-trained orthodontists performed the oral examinations. After collecting the valuable information, the descriptions and analyses were run by statistical software (SPSS, version 26.0). Results: 715 participants (334 boys and 381 girls) were involved in the analyses. As calculated, the current prevalence of malocclusion identified by Angle's classification was 45.6% in this sample. No evident relation between OSA-18 scores and dentofacial abnormalities (P > 0.05) was found. With the enlargement of tonsil size, the proportion of children with triangular dental arch form (P < 0.05) and high vault palate (P < 0.001) was increasingly higher. More children with protruding profiles and fewer upright profiles were observed as the tonsil size increased, although it did not show a statistical difference (P = 0.103). Conclusion: Dental and craniofacial growth deficiency has become more prevalent among children, demanding more concerns from health authorities. Tonsil hypertrophy plays an essential role in the direction of dentofacial development. More efforts from local health authorities should be made to enhance public propaganda and education on the prevention and interruption of tonsil hypertrophy and related dentofacial abnormalities.

Role of TRPC6 in periodontal tissue reconstruction mediated by appropriate stress.

INTRODUCTION: The basis of orthodontic tooth movement (OTM) is the reconstruction of periodontal tissue under stress. Increasing the speed of OTM has always been the focus of attention. OBJECTIVES: Periodontal ligament stem cells (PDLSCs) are direct effector cells of mechanical force, but the mechanism by which PDLSCs sense mechanical stimuli is unclear. METHODS: Human PDLSCs (hPDLSCs) were analyzed in the presence or absence of force loading with the Flexcell loading system in vitro. Then, periodontal tissues were analyzed after mechanical stimulation in vivo. In addition, cells in a confined microenvironment were analyzed to observe changes in the cytoskeleton and migration. Finally, TRPC6-/- mice were used to further verify the effect of TRPC6. After force application, the OTM distance, bone marrow density (BMD), TRPC6 and COL1 expression, and TRAP staining were evaluated in periodontal tissues. RESULTS: RNA sequencing (RNA-seq) and western blot analyses revealed that TRPC6 was important during mechanical force application to hPDLSCs. Appropriate mechanical force application also induced TRPC6 activation in the OTM model and the confined microenvironment. Under a slightly confined microenvironment, treatment with the TRPC6 inhibitor SKF96365 and TRPC6 knockout decreased the migration speed of hPDLSCs and mouse bone marrow mesenchymal stem cells (mBMSCs). In addition, TRPC6-/- mice showed lower OTM distances and reduced osteogenic and osteoclastic differentiation. CONCLUSION: In summary, TRPC6 activation in PDLSCs mediated by appropriate mechanical force application contributes to periodontal tissue reconstruction. PDLSCs modulate periodontal tissue remodeling under appropriate mechanical stimulation through TRPC6; however, under excessive stress, alveolar bone and tooth roots are readily absorbed. Under this condition, environmental factors play a leading role, and the regulatory effect of TRPC6 is not obvious.

Efficacy and safety of piezocision in accelerating maxillary anterior teeth en-masse retraction: study protocol for a randomized controlled trial.

BACKGROUND: Orthodontic treatment is commonly more time-consuming in adults than in teenagers, especially when it comes to the maxillary en-masse retraction, which may take 9 months or even longer. As to solve this concern, orthodontists have been striving to seek new methods for shortening orthodontic treatment time. Piezocision, as a popular alternative treatment, has been widely used in different types of tooth movement. However, its effect on en-masse retraction of maxillary anterior teeth remains unclear. This randomized controlled trial intends to figure out the role piezocision plays in accelerating en-masse retraction. METHODS: This protocol is designed for a prospective, single-center, assessor-blinded and parallel-group randomized controlled trial. Twenty adult patients aged from 18 to 40 whose orthodontic treatment required bilateral maxillary first premolars extraction will be randomly assigned to the piezocision group and the control group at a ratio of 1:1. The piezocision group will undergo en-masse retraction immediately after the piezo surgery, while the control group will start en-masse retraction directly. Both groups will be followed up every 2 weeks to maintain the retraction force until the end of space closure. The space closing time is set as the primary endpoint. Meanwhile, the secondary endpoints include the change of root length, labial and palatal alveolar bone thickness, vertical bone height, probing depth of maxillary anterior teeth, cephalometric measurements, visual analogue scale, and postoperative satisfaction questionnaire. DISCUSSION: This study will attempt to provide more convincing evidence to verify whether piezocision will shorten the time of en-masse retraction or not. Distinguished with previous studies, our study has made some innovations in orthodontic procedure and primary outcome measurement, aiming to clarify the efficacy and safety of piezocision-assisted en-masse retraction in Chinese population. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR 1900024297 . Registered on 5 July 2019.

Mild Hyperthermia-Assisted ROS Scavenging Hydrogels Achieve Diabetic Wound Healing.

Excessive reactive oxygen species (ROS) production induces oxidative damage to biomolecules, which can lead to the development of chronic diseases. Biocompatible hydrogel antioxidants composed of natural materials, such as polysaccharides and polyphenols, are of significant option for ROS scavenging. However, rapidly achieving hydrogel antioxidants with convenient, economical, safe, and efficient features remains challenging. Herein, facile synthesis of a physically cross-linked polyphenol/polysaccharide hydrogel by introducing tannic acid microsize particles (TAMP) into a cationic guar gum (CG) matrix is reported. Combining antioxidant/photothermal properties of TAMP and mechanical support from injectable CG, the formulated TAMP/CG is explored for treating diabetic wounds. Both in vitro and in vivo assays verify that TAMP/CG can protect the cells from ROS-induced oxidative damage, which can also be strengthened by the local photothermal heating (42 °C) triggered by near-infrared light. Overall, this study establishes the paradigm of enhanced diabetic wound healing by mild hyperthermia-assisted ROS scavenging hydrogels.

Engineering Robust Ag-Decorated Polydopamine Nano-Photothermal Platforms to Combat Bacterial Infection and Prompt Wound Healing.

Polydopamine (PDA) nanoparticles have emerged as an attractive biomimetic photothermal agent in photothermal antibacterial therapy due to their ease of synthesis, good biodegradability, long-term safety, and excellent photostability. However, the therapeutic effects of PDA nanoparticles are generally limited by the low photothermal conversion efficiency (PCE). Herein, PDA@Ag nanoparticles are synthesized via growing Ag on the surface of PDA nanoparticles and then encapsulated into a cationic guar gum (CG) hydrogel network. The optimized CG/PDA@Ag platform exhibits a high PCE (38.2%), which is more than two times higher than that of pure PDA (16.6%). More importantly, the formulated CG/PDA@Ag hydrogel with many active groups can capture and kill bacteria through effective interactions between hydrogel and bacteria, thereby benefiting the antibacterial effect. As anticipated, the designed CG/PDA@Ag system combined the advantages of PDA@Ag nanoparticles (high PCE) and hydrogel (preventing aggregation of PDA@Ag nanoparticles and possessing inherent antibacterial ability) is demonstrated to have superior antibacterial efficacy both in vitro and in vivo. This study develops a facile approach to boost the PCE of PDA for photothermal antibacterial therapy, providing a significant step forward in advancing the application of PDA nano-photothermal agents.

Facile formation of injectable quaternized chitosan/tannic acid hydrogels with antibacterial and ROS scavenging capabilities for diabetic wound healing.

The wound healing process of the diabetic wound is often hindered by excessive oxygen free radicals and infection. An ideal wound dressing should possess great reactive oxygen species (ROS) scavenging property and considerable antibacterial ability. In this study, we facilely constructed a novel hydrogel dressing with excellent ROS scavenging property and outstanding antibacterial performance by introducing tannic acid (TA) into quaternized chitosan (QCS) matrix. Attributing to the suitable physical crosslinking between TA and QCS, this QCS/TA hydrogel was endowed with injectable and self-healing properties, which could avoid the various external squeezing on the irregular shape by wound dressing. The results showed that it could promote coagulation, suppress inflammation and expedite collagen deposition in the skin defect model of diabetic rats. This study provides a facile and convenient method for constructing injectable hydrogel dressing, which has application potentials in the clinical management of diabetic wounds.

ε­Polylysine-stabilized agarose/polydopamine hydrogel dressings with robust photothermal property for wound healing.

Polydopamine (PDA) is emerging as an attractive photothermal agent due to its good photothermal performance and excellent biocompatibility. However, without chemical modification, PDA is normally unstable and usually leached out from the constructed biomaterials, realistically limiting its application space. Here, we constructed a new hydrogel dressing with robust and stable photothermal performance by introduction of ε-Polylysine (ε-PL) into agarose/PDA matrix to efficiently lock PDA. By optimizing PDA/ε-PL rational dose in agarose network structure, a hybrid agarose/PDA/ε-PL hydrogel (ADPH) with stable photothermal functionality and desirable physicochemical properties could be achieved. ADPH possessed satisfactory microbicidal efficacy in vivo, which enabled the bacteria-infected skin wound to be cured quickly by successful suppressing inflammation, accelerating collagen deposition and promoting angiogenesis in a bacterial-infected wound model. Collectively, this study illustrates a simple, convenient but powerful strategy to design functionally stable ADPH dressing for treating dermal wounds, which could open vistas in clinical wound management.

Polydopamine/montmorillonite-embedded pullulan hydrogels as efficient adsorbents for removing crystal violet.

Both secondary pollution and the low mechanical strength of adsorbents have severely impeded the practical application of adsorption methods in the dye wastewater treatment. In this work, we innovatively synthesized a composite hydrogel adsorbent by incorporating polydopamine (PDA) and montmorillonite (MMT) into the pullulan hydrogel matrix for dye adsorption. First, the successful formation of the resultant adsorbents was verified by Fourier-transform infrared spectroscopy and scanning electron microscope elemental mapping analysis. Then, several physicochemical properties (such as thermal and swelling properties, microarchitecture, and mechanical strength) of the five prepared adsorbents (PM1-PM5) were investigated. These results demonstrated the adsorbents had tunable properties, which can be achieved by adjusting the PDA/MMT mass ratio. Next, the dye adsorption performance was systematically explored. The resultant adsorbent (PM3) had a maximum adsorption capacity of 112.45 mg/g and its adsorption data was best described by a Langmuir isotherm and pseudo-second-order kinetic. Finally, the adsorption mechanisms and potential commercial practicability of the adsorbent were studied. Altogether, the designed adsorbent could effectively avoid generating the secondary pollution typical of adsorbents and it displayed excellent mechanical strength, thus opening up a new horizon in mitigating environmental pollution from textile industries.

Polydopamine-incorporated dextran hydrogel drug carrier with tailorable structure for wound healing.

Effective methods to treat bacterial infections are highly desired as the abuse of antibiotics has caused multidrug-resistant. Polysaccharide hydrogel-based drug delivery systems possessing inherent large surface area and biocompatibility attributes provide a promising strategy for effective use of antibiotics. Here, we presented an effective method for fabricating macroporous polysaccharide hydrogels composed of dextran (DP) and polydopamine (PDA) for controlled release of antibiotics. The physicochemical properties of resulting DP hydrogels were systematically evaluated by measuring their swelling, viscoelasticity, morphology, sorption and thermal stability, and we could control these properties through simply changing the PDA concentration in a pre-gel solution. The low cytotoxicity of DP hydrogels was demonstrated through a co-culture with mouse fibroblast cells. Moreover, in vitro/vivo antibacterial properties of the drug-loading DP hydrogels were evaluated, and they exhibited good antibacterial and healing performances. We believe that the proposed strategy for facilitation and optimization of polysaccharide hydrogels could offer more hydrogel dressings when choosing suitable carriers for sustained release of antibiotics.

Construction of functional curdlan hydrogels with bio-inspired polydopamine for synergistic periodontal antibacterial therapeutics.

Curdlan, a bacteria-derived polysaccharide resource, possesses substantial potential for periodontal antimicrobial delivery. Here, the facile engineering of a functionalized curdlan/polydopamine (PDA) composite hydrogels was reported. The physiochemical evaluations of composite hydrogels proved their tunable properties associated with concentration of PDA including pore size, rheological property and swelling behavior. We have systematically assessed biocompatibility in vitro and found these hydrogels toxicity-free. Moreover, photothermal performance upon near infrared light (NIR) exposure was conducted and eventually indicated the best matches for antibacterial application. The acetate chlorhexidine (CHX) was chosen as a model antimicrobial and the release profiles demonstrated the entrapped CHX could be triggered and nicely controlled by NIR. The optimized bacteriostatic rate reached 99.9 %. Overall, we aimed to provide new curdlan-based hydrogels for periodontal antibacterial treatment by combining photothermal effect and antimicrobial simultaneously.

Sustainable, flexible and biocompatible hydrogels derived from microbial polysaccharides with tailorable structures for tissue engineering.

Polysaccharides derived from microorganisms have received considerable attention in designing hydrogel materials. However, most microbial polysaccharide-constructed hydrogels evaluated in preclinical trials are not favorable candidates for biomedical applications owing to concerns regarding poor mechanical strength and complicated fabrication process. Herein, we describe a new polysaccharide hydrogel scaffold containing salecan together with gellan gum network as the polymeric matrix. Properly controlling the physical and chemical properties including swelling, water release, thermal stability, viscoelasticity and morphology of the resulting gel are easily achieved by simply changing the salecan/gellan gum ratios. Notably, these salecan/gellan gum scaffolds friendly support cell survival and proliferation. More significantly, we have systematically evaluated these developed hydrogels for the biocompatible experiments in vitro and in vivo and results indicated the products are non-toxic. Taken together, such hydrogels derived from microbial polysaccharides and readily synthesized through a one-step mixing protocol have translational potentials in the clinic serving as cell devices for tissue engineering.

Macroporous Hydrogel Scaffolds with Tunable Physicochemical Properties for Tissue Engineering Constructed Using Renewable Polysaccharides.

Polysaccharides have recently attracted increasing attention in the construction of hydrogel devices for biomedical applications. However, polysaccharide-based hydrogels are not suitable for most preclinical applications because of their limited mechanical properties and poor tunability. In this study, we employed a simple and eco-friendly approach to producing a macroporous polysaccharide hydrogel composed of salecan and κ-carrageenan without the use of toxic chemicals. We evaluated the physicochemical properties of the obtained salecan/κ-carrageenan hydrogel and found that its viscoelasticity, morphology, swelling, and thermal stability could be simply controlled by changing the polysaccharide dose in the pre-gel solution. The co-incubation of the fabricated hydrogel with mouse fibroblast cells demonstrated that the hydrogel can support cell adhesion, migration, and growth. Moreover, the hydrogel exhibited good biocompatibility in vivo. Overall, the findings provide a new strategy for the fabrication and optimization of polysaccharide-based hydrogel scaffolds for application in tissue engineering.

Biocompatible Hydrogels Based on Food Gums with Tunable Physicochemical Properties as Scaffolds for Cell Culture.

Hydrogels composed of food gums have gained attention for future biomedical applications, such as targeted delivery and tissue engineering. For their translation to clinical utilization, reliable biocompatibility, sufficient mechanical performance, and tunable structure of polysaccharide hydrogels are required aspects. In this work, we report a unique hybrid polysaccharide hydrogel composed of salecan and curdlan, in which the former is a thickening agent and the latter serves as a network matrix. The physicochemical properties, such as mechanical strength, thermal stability, swelling, and morphology, of the developed composite hydrogel can be accurately modulated by varying the polysaccharide content. Importantly, cytotoxicity assays show the non-toxicity of this hybrid hydrogel. Furthermore, this hydrogel system can support cell proliferation, migration, and function. Altogether, our work proposes a new strategy to build a polysaccharide-constructed hydrogel scaffold, which holds much promise for tissue engineering in terms of cell engraftment, survival, proliferation, and function.

TAZ contributes to osteogenic differentiation of periodontal ligament cells under tensile stress.

BACKGROUND AND OBJECTIVE: Bone remodeling during orthodontic treatment is achieved by the osteogenesis of human periodontal ligament cells (PDLCs) subjected to mechanical loadings. Transcriptional co-activator with PDZ-binding motif (TAZ) mediates bone remodeling in response to extracellular mechanical signals. This study aims to investigate the role of TAZ in osteogenesis of PDLCs under tensile strain. MATERIALS AND METHODS: A uniaxial cyclic tensile stress (CTS) at 12% elongation and 6 cycles/min (5 s on and 5 s off) was applied to PDLCs. The osteogenic differentiation was determined by the protein and gene expressions of osteogenic markers using qRT-PCR and Western blot, respectively, and further by alkaline phosphatase (ALP) activity and Alizarin Red S staining. The interaction of TAZ with core-binding factor α1 (Cbfα1) was examined by co-immunoprecipitation. The immunofluorescence histochemistry was used to examine the nucleus aggregation of TAZ and the reorganization of actin filaments. Moreover, small interfering RNA-targeting TAZ (TAZsiRNA) was used for TAZ inhibition and Y-27632 was employed for Ras homologue-associated coiled-coil protein kinase (ROCK) signaling blockage. RESULTS: CTS clearly stimulated the nucleus accumulation of TAZ and its interaction with Cbfα1. CTS-induced osteogenesis in PDLCs was significantly abrogated by the infection with TAZsiRNA, as shown by the decreased stained nodules and protein expressions of Cbfα1, collagen type I, osterix, and osteocalcin, along with the inhibition of ß-catenin signaling. Moreover, ROCK inhibition by Y-27632 hindered TAZ nucleus aggregation and its binding with Cbfα1, which subsequently lead to the decreased osteoblastic differentiation of PDLCs. CONCLUSIONS: Taken together, we propose that TAZ nucleus localization and its interaction with Cbfα1 are essential for the CTS-induced osteogenic differentiation in PDLCs. And such TAZ activation by CTS could be mediated by ROCK signaling, indicating the pivot role of ROCK-TAZ pathway for PDLCs differentiation.

Efficient decontamination of heavy metals from aqueous solution using pullulan/polydopamine hydrogels.

Designing a new adsorbent with recyclability, high efficiency and biodegradability is important for treating heavy metals contamination but remains a severe challenge. In this work, a novel type of hydrogel biosorbents based on pullulan and polydopamine were designed for heavy metal ions removal from aqueous solution. The physicochemical properties of the prepared pullulan/polydopamine (Pu/PDA) hydrogels were fully characterized by thermal gravimetric analysis, Fourier transform infrared spectroscopy, rheology, scanning electron microscopy, swelling and compression tests. We observed that their mechanical strength, pore size, water absorption and retention properties could be nicely controlled by adjusting the PDA concentration in the pre-gel solution. Subsequently, the adsorption ability of designed Pu/PDA hydrogels to Cu2+, Co2+ and Ni2+ was investigated in detail. These hydrogels presented excellent adsorption capability for heavy metal ions and matched well with the pseudo-second-order kinetic model and Freundlich isotherm model. Overall, having tunable physicochemical properties coupled with the high absorption ability for heavy metal ions, these Pu/PDA hydrogels may be a promising strategy for removal of pollutants from aqueous solution.

Facile formation of salecan/agarose hydrogels with tunable structural properties for cell culture.

Salecan polysaccharide produced by Agrobacterium sp. ZX09 is an attractive biopolymer to construct hydrogel scaffolds for cell culture. However, some limitations such as poor mechanical performance, complicated fabrication process and slow gelation times still exist in the biomedical applications of microbial-based salecan polysaccharide hydrogels. Here, a series of polysaccharide hydrogels composed of salecan and agarose with adjustable structural properties are designed. The resultant hybrid salecan/agarose hydrogels exhibit controllable physical and chemical properties including thermal stability, water uptake, mechanical strength and microarchitecture, which can be readily realized with minimum change of the polysaccharide content. Furthermore, cytotoxicity assays reveal that the designed composite hydrogels are non-toxic. More importantly, these hydrogels support cell survival, proliferation, and migration. Together, this work opens up a new avenue to build polysaccharide hydrogel platforms for tissue engineering.