Uptight responses between clenching and forearm raising with factors of visual feedback and maintenance effort in healthy young women: An experimental study on factorial design.

BACKGROUND: To achieve different central preset force levels requires various fine-tuning efforts and may elicit different uptight responses. The mandibular lever system has a distinct regularity in the fine-tuning function of the upper limbs. The purpose of the present study was to detect whether the uptight responses elicited from motivating clenching differ from those induced by motivating forearm raising at different force levels. METHODS: Twenty-five healthy females were enrolled in this study. The target was low, medium, and maximum force levels with or without visual feedback and/or maintenance effort. Surface electromyographic (SEMG) activity was recorded from the bilateral anterior temporalis and masseter or left biceps brachii muscle (BicL), and the T-Scan III System synchronously recorded the sensitive force values. The uptight responses and task difficulties were recorded for occlusal and left forearm lifting tasks using a unique visual analogue scale. RESULTS: The highest uptight response value was achieved at a low clenching force level with visual feedback requiring no maintenance effort but at a maximum forearm-raising force level with visual feedback and maintenance effort. The SEMG activities of both jaw-closing muscles and BicL were associated with the central preset force level (P < 0.001). However, the maintenance effort only increased the jaw-closing muscles' SEMG activity at the maximal force level (P < 0.001). CONCLUSIONS: Clenching at the central preset lower force level with visual feedback is prone to elicit a higher degree of uptight response. The constant need for a low-intensity bite can have a negative effect on an individual's mood.

Sustained release of collagen VI potentiates sciatic nerve regeneration by modulating macrophage phenotype.

Although the peripheral nervous system has an intrinsic ability for repair and regeneration after injury, bridging long peripheral nerve defects remains a challenge. Functional nerve regeneration depends on interactions among axons, Schwann cells, fibroblasts and immune cells. Macrophages, as immune cells recruited early in this process, show polarization toward phenotypes that are detrimental or beneficial to tissue remodeling depending on the microenvironment of the scaffolds. In this study, we investigated the effects of macrophage phenotypes modulated by collagen VI on axonal regeneration and functional recovery by bridging a 15-mm-long sciatic nerve defect in rats. Our results showed that local delivery of collagen VI within a polycaprolactone (PCL) electrospun conduit increased the recruitment of macrophages and their polarization toward the pro-healing (M2) phenotype. In addition, the axonal regeneration and neurologic functional recovery in the PCL/collagen VI conduit group are equivalent to that of an autograft. In conclusion, the present study confirmed that PCL/collagen VI conduits with sustained release of collagen VI in the local microenvironment may, through triggering macrophage M2 polarization to enhance the nerve regeneration, suggest that our combined biomaterial-immunomodulatory system may be an attractive candidate for peripheral nerve regeneration.

N-acyl homoserine lactones lactonase est816 suppresses biofilm formation and periodontitis in rats mediated by Aggregatibacter actinomycetemcomitans.

Aims: The current study aimed to explore the adjuvant therapeutic effect of N-acyl homoserine lactones (AHLs)-lactonase est816 on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biological behaviors and periodontitis progression. Methods: The inhibitory properties of est816 were detected by live/dead bacterial staining, scanning electron microscope (SEM), crystal-violet staining and reverse-transcription quantitative PCR (RT-qPCR). Biocompatibility of est816 on human gingival fibroblasts (HGFs) and human gingival epithelial cells (HGEs) was evaluated by CCK8 and ELISA. The ligature-induced periodontitis model was established in rats. Micro computed tomography and immunohistochemical and histological staining served to evaluate the effect of est816 on the prevention of periodontitis in vivo. Results: est816 significantly attenuated biofilm formation, reduced the mRNA expression of cytolethal distending toxin, leukotoxin and poly-N-acetyl glucosamine (PNAG) and downregulated expressions of interleukin-6 and tumor necrosis factor-α with low cell toxicity. In vivo investigations revealed est816 decreased alveolar bone resorption, suppressed matrix metalloproteinase-9 expression and increased osteoprotegerin expression. Conclusion: est816 inhibited A. actinomycetemcomitans biofilm formation and virulence release, resulting in anti-inflammation and soothing of periodontitis in rats, indicating that est816 could be investigated in further research on periodontal diseases.

Bone Graft Materials for Alveolar Bone Defects in Orthodontic Tooth Movement.

Clinically, orthodontic tooth movement (OTM) across the narrow alveolar ridge area inevitably entails some adverse reactions such as limited movement and periodontal tissue damage. Hence, it is essential to reconstruct the morphology of the alveolar crest before the tooth movement. Unlike the routine reconstruction of alveolar ridge in the field of implant, the orthodontic practices are distinctive, which require dental movement across the constructed alveolar ridge with safety and stability. Herein, we addressed the pros and cons of reconstruction of the defected orthodontic alveolar ridge with different bone graft materials. Attention is also paid to other factors such as the postgraft initiation time of OTM that can substantially influence the bone reconstruction and tooth movement effect. Rather, considering the lack of a unified standard in orthodontic clinics related to bone reconstruction for OTM, we provide some recommendations and guidance for OTM through alveolar ridge defect area. Impact statement Re-establishment of the atrophic alveolar bone before orthodontic tooth movement (OTM) is important for safe and efficient tooth movement. The most prevalent approach to regenerate alveolar bone in the defect rests on the application of bone grafts. This review evaluates the application of different bone graft materials to the reconstruction of alveolar ridge defects, and provides some recommendations and guidance for OTM through alveolar ridge defect area.

Management of type IIIb dens invaginatus using a combination of root canal treatment, intentional replantation, and surgical therapy: A case report.

BACKGROUND: Type Ⅲb dens invaginatus (DI) with a lateral canal located at the mid-third of the root is rarely reported. Here, we report a rare case of type Ⅲb DI in the left upper anterior tooth with a lateral canal that led to persistent periodontitis. CASE SUMMARY: A 15-year-old female patient presented with a chief complaint of pain associated with recurrent labial swelling in the area of the left anterior tooth. A diagnosis of type Ⅲb DI and chronic periodontitis was made. Intentional replantation was performed after conventional endodontic treatment failed. After 6 mo, the patient was asymptomatic, but a sinus tract was observed. Cone-beam computed tomography images showed bone loss in the mesial of the mid-root. Based on methylene blue staining and microscopy images, the lateral foramen located at the middle third of the root was surgically treated. After 3 years of follow-up, the clinical findings and radiographic assessment presented a favorable prognosis of bone healing without root absorption or ankylosis. CONCLUSION: Type Ⅲb DI with a lateral canal can be successfully treated by root canal treatment, intentional replantation, and surgical therapy.

Bioactive Nanocomposite Microsponges for Effective Reconstruction of Critical-Sized Calvarial Defects in Rat Model.

Introduction: Micro-sized sponge particulates have attracted extensive attention because of their potential to overcome the intrinsic limitations of conventional monolithic scaffolds in tissue engineering. Bioactive nanocomposite microsponges are regarded as potential bone substitute materials for bone regeneration. Methods: Based on a combination of microfluidic emulsion with further freezing and in situ thawing, chitosan (CS)-hydroxyapatite (HAP) microsponges were prepared and characterized in terms of their morphology and elemental distribution using a scanning electron microscope equipped with an X-ray detector. The swelling ratio, porosity, degradability, antibacterial activity, and bioactivity were detected and analyzed. The biological functions of the CS-HAP microsponges were examined to assess the adhesion, proliferation, and differentiation of in vitro co-cultured rat bone marrow mesenchymal stem cells (rBMSCs). Furthermore, the CS-HAP microsponges were used as cell-free scaffolds and implanted into calvarial defects in a rat model to evaluate the in vivo osteogenesis. Results: The CS-HAP microsponges have a porous structure with high porosity (~76%), good swelling capacity (~1900%), and shape-memory properties. The results of in vitro experiments show that the CS-HAP microsponges achieve good bioactivity and promote osteogenic differentiation of rBMSCs. Furthermore, the CS-HAP microsponges significantly promote bone regeneration in rat calvarial defects. Conclusion: The bioactive CS-HAP microsponges have the potential to be used as bone substitute materials for bone tissue engineering.

Upregulation of ETV2 Expression Promotes Endothelial Differentiation of Human Dental Pulp Stem Cells.

The lack of vasculogenesis often hampers the survivability and integration of newly engineered tissue grafts within the host. Autologous endothelial cells (ECs) are an ideal cell source for neovascularization, but they are limited by their scarcity, lack of proliferative capacity, and donor site morbidity upon isolation. The objective of this study was to determine whether differentiation of human dental pulp stem cells (DPSCs) into the endothelial lineage can be enhanced by recombinant ETV2 overexpression. DPSCs were extracted from fresh dental pulp tissues. ETV2 overexpression in DPSCs was achieved by lentiviral infection and cellular morphological changes were evaluated. The mRNA and protein expression levels of endothelial-specific markers were assessed through quantitative real-time polymerase chain reaction, western blot, immunofluorescence staining, and flow cytometry. The tube formation assay and Matrigel plug assay were also performed to evaluate the angiogenic potential of the ETV2-transduced cells in vitro and in vivo, respectively. Additionally, proteomic analysis was performed to analyze global changes in protein expression following ETV2 overexpression. After lentiviral infection, ETV2-overexpressing DPSCs showed endothelial-like morphology. Compared with control DPSCs, significantly higher mRNA and protein expression levels of endothelial-specific genes, including CD31, VE-Cadherin, VEGFR1, and VEGFR2, were detected in ETV2-overexpressing DPSCs. Moreover, ETV2 overexpression enhanced capillary-like tube formation on Matrigel in vitro, as well as neovascularization in vivo. In addition, comparative proteomic profiling showed that ETV2 overexpression upregulated the expression of vascular endothelial growth factor (VEGF) receptors, which was indicative of increased VEGF signaling. Taken together, our results indicate that ETV2 overexpression significantly enhanced the endothelial differentiation of DPSCs. Thus, this study shows that DPSCs can be a promising candidate cell source for tissue engineering applications.

[Effect evaluation of medical calcium sulfate--OsteoSet in repairing jaw bone defect].

OBJECTIVE: To investigate the effectiveness of the medical calcium sulfate-OsteoSet bone graft substitute in the treatment of defect after excision of jaw cyst. METHODS: Between December 2009 and May 2010, 15 cases of jaw cystic lesion were treated, including 9 males and 6 females with an average age of 36.6 years (range, 15-75 years). Orthopantomography (OPT) method was used to measure the cyst size before operation, and the size ranged from 1.5 cm x 1.5 cm to 8.0 cm x 3.0 cm. The range of bone defect was from 1.5 cm x 1.5 cm x 1.5 cm to 8.0 cm x 3.0 cm x 3.0 cm after cyst excision intraoperatively. The patients underwent cyst curettage and OsteoSet bone graft substitutes implantation (2-15 mL). Radiological method was used to evaluate the repair effect of OsteoSet pellets. RESULTS: The pathology biopsy was periapical cyst in 7 cases, odontogenic keratocyst in 5 cases, and dentigerous cyst in 3 cases. Fifteen patients were followed up 6-12 months. Thirteen patients achieved wound healing by first intention; 2 cases had longer drainage time (5 and 7 days, respectively), the incision healed after the pressure bandage. Swelling occurred in 1 case after 1 month with no symptom of infection. No postoperative infection and rejection was found. The X-ray examination showed that the materials filled the bone defect well after 1 day of operation. OsteoSet bone graft substitutes were absorbed by one-half after 1 month of operation and totally after 3 months by OPT. The low density area was smaller in the original cysts cavity, and high density in the cysts increased significantly with fuzzy boundaries of cysts. At 6 months after operation, there was no obvious difference in image density between the original cavity and normal bone, and the capsule cavity boundary disappeared, and defect area was full of new bone. CONCLUSION: The medical calcium sulfate-OsteoSet bone graft substitute is an ideal filling material for bone defect.

Structure-defined c60/polymer colloids supramolecular nanocomposites in water.

We report a new supramolecular method for the synthesis of well-defined pristine C 60/polymer colloid nanocomposites in water. The colloids include polymer micelles and emulsion particles. To a polymer colloid solution in water or alcohol, we introduced C 60 solution in a solvent that is miscible with water or alcohol. After the two solutions mixed, polymer colloids and C 60 spontaneously assembled into stable colloidal nanocomposites. After a dialysis process, a nanocomposite dispersion in pure water was obtained. As characterized by DLS and (Cryo-)TEM, the nanocomposites have a core-shell structure with C 60 aggregated on the surface of emulsion particles or micellar cores. The resulting nanocomposites have many potential applications such as biomedicals and photovoltaics.