Residue quality drives SOC sequestration by altering microbial taxonomic composition and ecophysiological function in desert ecosystem.

Plant residues are important sources of soil organic carbon in terrestrial ecosystems. The degradation of plant residue by microbes can influence the soil carbon cycle and sequestration. However, little is known about the microbial composition and function, as well as the accumulation of soil organic carbon (SOC) in response to the inputs of different quality plant residues in the desert environment. The present study evaluated the effects of plant residue addition from Pinus sylvestris var. mongolica (Pi), Artemisia desertorum (Ar) and Amorpha fruticosa (Am) on desert soil microbial community composition and function in a field experiment in the Mu Us Desert. The results showed that the addition of the three plant residues with different C/N ratios induced significant variation in soil microbial communities. The Am treatment (low C/N ratio) improved microbial diversity compared with the Ar and Pi treatments (medium and high C/N ratios). The variations in the taxonomic and functional compositions of the dominant phyla Actinobacteria and Proteobacteria were higher than those of the other phyla among the different treatments. Moreover, the network links between Proteobacteria and other phyla and the CAZyme genes abundances from Proteobacteria increased with increasing residue C/N, whereas those decreased for Actinobacteria. The SOC content of the Am, Ar and Pi treatments increased by 45.73%, 66.54% and 107.99%, respectively, as compared to the original soil. The net SOC accumulation was positively correlated with Proteobacteria abundance and negatively correlated with Actinobacteria abundance. These findings showed that changing the initial quality of plant residue from low C/N to high C/N can result in shifts in taxonomic and functional composition from Actinobacteria to Proteobacteria, which favors SOC accumulation. This study elucidates the ecophysiological roles of Actinobacteria and Proteobacteria in the desert carbon cycle, expands our understanding of the potential microbial-mediated mechanisms by which plant residue inputs affect SOC sequestration in desert soils, and provides valuable guidance for species selection in desert vegetation reconstruction.

Programmed release of vascular endothelial growth factor and exosome from injectable chitosan nanofibrous microsphere-based PLGA-PEG-PLGA hydrogel for enhanced bone regeneration.

The healing of large bone defects remains a significant challenge in clinical practice. Accelerating both angiogenesis and osteogenesis can promote effective bone healing. In the natural healing process, angiogenesis precedes osteogenesis, providing a blood supply that supports the subsequent progression of osteogenesis. Developing a biomimetic scaffold that mimics the in vivo environment and promotes the proper sequence of vascularization followed by ossification is crucial for successful bone regeneration. In this study, a novel injectable dual-drug programmed releasing chitosan nanofibrous microsphere-based poly(D, l-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(D,l-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel is fabricated by incorporating vascular endothelial growth factor (VEGF) and microspheres loaded with dental pulp stem cells-derived exosomes (DPSCs-Exo). Rapid release of VEGF promotes the swift initiation of angiogenesis, while DPSCs-Exo release ensures persistent osteogenesis. Our results demonstrate that chitosan microsphere-based PLGA-PEG-PLGA hydrogel significantly promotes angiogenesis in human umbilical vascular endothelial cells and enhances the osteogenic differentiation of pre-osteoblasts. Furthermore, in vivo transplantation of this injectable chitosan microsphere-based PLGA-PEG-PLGA hydrogel into calvarial bone defects markedly promotes bone formation. Overall, our study provides a promising approach for improving bone regeneration by temporally replicating the behavior of angiogenesis and osteogenesis.

Application of Nanocellulose-Based Aerogels in Bone Tissue Engineering: Current Trends and Outlooks.

The complex or compromised bone defects caused by osteomyelitis, malignant tumors, metastatic tumors, skeletal abnormalities, and systemic diseases are difficult to be self-repaired, leading to a non-union fracture. With the increasing demands of bone transplantation, more and more attention has been paid to artificial bone substitutes. As biopolymer-based aerogel materials, nanocellulose aerogels have been widely utilized in bone tissue engineering. More importantly, nanocellulose aerogels not only mimic the structure of the extracellular matrix but could also deliver drugs and bioactive molecules to promote tissue healing and growth. Here, we reviewed the most recent literature about nanocellulose-based aerogels, summarized the preparation, modification, composite fabrication, and applications of nanocellulose-based aerogels in bone tissue engineering, as well as giving special focus to the current limitations and future opportunities of nanocellulose aerogels for bone tissue engineering.

Enrichment of antibiotic resistance genes in roots is related to specific bacterial hosts and soil properties in two soil-plant systems.

Soil microorganisms carrying antibiotic resistance genes (ARGs) can colonize plants as endophytes, posing a huge risk to human health. However, the distribution and transmission patterns of ARGs in different soil-plant systems are unclear. Here, we investigated the distribution of ARGs and the microbial communities in the soil-wheat and soil-cucumber systems by quantitative PCR (qPCR) and 16S rRNA gene sequencing. The results showed that the relative abundances of seven ARGs and intI1 in roots were higher than those of other samples in both soil-plant systems. Pseudomonas, Enterobacteriaceae, Rhizobiales and Gammaproteobacteria were dominant potential bacterial hosts of endophytic ARGs, with enrichment patterns similar to that of ARGs in roots. In addition, more ARGs were significantly positively correlated with intI1 in roots, indicating that ARGs may be more prone to horizontal gene transfer (HGT). Variation partitioning analysis (VPA) and structural equation models (SEM) revealed that the variations of ARGs were mainly directly affected by the HGT of intI1 and indirectly affected by soil properties in roots. These results demonstrated that root could have a strong proliferative effect on ARGs entering host plant endophytes. Overall, our findings enhanced the understanding distribution patterns of ARGs in different soil-plant systems, and provided an effective basis for developing measures to minimize the spread of ARGs.

Serious Condylar Head Absorption in Children With Intracapsular Condylar Fractures Treated Operatively With Long Screws.

OBJECTIVE: This study was performed to explore bone remodelling in children with intracapsular condylar fractures after the condylar fracture fragments were fixed using long screws and to offer possible explanations about the underlying mechanism. PATIENT AND METHODS: Records of children (less than 12 y old) who sustained intracapsular condylar fractures and fixed with long screws from May 2012 to January 2015 were retrieved. Age, gender, dates of injury, admission, and discharge, mechanism of trauma, location and pattern of fracture, other mandibular fractures, treatment methods, and time of review were recorded and analyzed. Image dates of pretreatments and posttreatments, including the date of review, were also recorded. RESULTS: A total of 8 patients completed their follow-up, and all patients (n=5) who were followed up after more than 3 months showed serious resorption of the condylar head. The condylar head resorbed until the height (or articular surface) dropped and aligned with the surface of the screw. The shortest time of absorption, as shown by the computed tomography scan was 106 days, and the longest time was 171 days (average time of 141.8 d). CONCLUSIONS: Intracapsular condyle fractures in children should be managed conservatively as much as possible. However, if the height of the fracture fragments drops remarkably, open reduction and rigid internal fixation become possible choices.

Design and Use of a Pair of Computer-Designed Surgical Templates in Reduction of a Comminuted Zygomatic Arch Fracture.

BACKGROUND: Isolated depressed zygomatic arch fractures are often treated with closed reduction. Reduction is usually performed through the Gillies approach or Keen approach. comminuted zygomatic arch fractures generally require open reduction and fixation to achieve good results. This article describes how to use a pair of surgical templates to assist in the fixation of comminuted zygomatic arch fractures with absorbable plates. METHODS: A pair of computer-designed surgical templates were applied to restore the main part of zygomatic arch. Placing a surgical template on the medial side of the zygomatic arch can provide a supporting force and improves the stability of the reduced bone fragments. The lateral template of zygomatic arch limits the excessive uplift of bone fragments. RESULTS AND DISCUSSION: The operation was performed according to the predetermined procedure. Postoperative computed tomography showed satisfactory reduction effect. In conclusion, with the aid of surgical templates, the reduction and fixation of comminuted zygomatic arch fractures can be more easily performed using absorbable plates.

Fracture fragment of the condyle determines the ramus height of the mandible in children with intracapsular condylar fractures treated conservatively.

This study aimed to explore and impart understanding of bone remodelling in children with intracapsular fractures treated conservatively. Records of children (less than 12 years), who sustained intracapsular fractures and treated conservatively, were retrieved consecutively for the period of March 2011 to February 2016. Data about age, gender, date of injury, dates of admission and discharge, mechanism of trauma, location and pattern of fracture, other mandibular fractures, treatment methods and time of review were recorded and analysed. Image dates of pre- and post-treatments, including date of review, were also recorded. A total of 22 patients complete their follow-up and show bone remodelling process. During their follow-up, all the displaced condylar fragments fused with the ramus stump at the displaced position. Regardless of the type of conservative procedure, both treatments cannot promote the spontaneous fracture reduction in patients with intracapsular condylar fractures. During follow-up, the absorption of the lateral process of the condyle after the closed treatment becomes close to the 'horizontal absorption', until the height (or articular surface) of the lateral condylar process dropped and aligned to the articular surface of the medial process. In children with intracapsular condylar fractures, the fracture fragment of the condyle determines the ramus height of the mandible. Closed treatment cannot restore the fracture fragment. If the height of the fracture fragments dropped remarkably, then open reduction and rigid internal fixation become more suitable.

Treatment of Sagittal Fracture of the Mandibular Condyle Using Resorbable-Screw Osteosynthesis.

PURPOSE: Screw osteosynthesis is advocated for the treatment of sagittal fracture of mandibular condyle (SFMC). This study aimed to explore the applicability of resorbable-screw osteosynthesis in the treatment of SFMC. METHODS: A retrospective cohort study was performed in patients with SFMC treated with resorbable-screw osteosynthesis (group A) from June 2011 through June 2021. The patients who had undergone titanium-screw osteosynthesis served as the control group (group B). The primary outcome variable was fracture healing, defined as follows: 1) normal mouth opening and restoration of pretrauma occlusion; 2) without complications or discomfort of temporomandibular joint symptoms; and 3) fracture union without abnormal reactions or bone resorption in computed tomography images. The secondary outcome variable was condylar morphological changes including radiographic imaging appearance of the condyle, mandibular ramus height (MRH), anteroposterior diameter (APD), and mediolateral diameter (MLD) of the condyle, which were assessed by comparing the computed tomography images 1 week after surgery with those of 3 months after surgery. The collected data of the outcome variables of the 2 groups were analyzed correspondingly using Student's paired t test and Student's t test. RESULTS: There were 24 patients in group A and 71 patients in group B. All the patients displayed an evident improvement in mouth opening and restored pretrauma occlusion. Few patients had complications (group A, 8.33%; group B, 9.86%) and discomfort of temporomandibular joint symptoms (group A, 16.67%; group B, 15.49%). Fracture union without abnormal reactions or bone resorption was observed during the follow-up. The radiographic evaluation revealed no significant difference in the MRH, the maximum APD, and MLD of the condyles between 1 week and 3 months after surgery in both groups. There were no significant intergroup differences in the changes in the MRH, APD, and MLD of the condyles. CONCLUSIONS: Resorbable-screw osteosynthesis is a viable option for the treatment of SFMC.

Removal of Fracture Fragments in Intracapsular Condylar Fractures: An Alternative Treatment Option.

OBJECTIVE: This study aimed to explore bone remodeling after condylar fracture fragments have been removed from patients with intracapsular condylar fractures. it also evaluated whether condyle fracture removal can be used alternatively when the authors treat patients with comminuted or small pieces of fracture or in extremely difficult operations. METHODS: Records of patients who sustained intracapsular condylar fractures and treated by removal of fragments for the period of February 2013 to September 2019 were retrieved. Data about age, gender, date of injury, dates of admission and discharge, mechanism of trauma, location and pattern of fracture, other mandibular fracture, treatment methods and time of review were recorded and analyzed. Image dates of pre- and post-treatment (including the time of review) were also recorded. RESULTS: The data of a total of 103 patients ranging from 5 to 84 years old were retrieved during this study. A total of 135 sides of condylar fragments were removed. Almost all of the patients with comminuted condyle head fracture or type A fracture presented apparent shortening of the ramus height, and none of them showed osteogenesis (or new bone formation) during their follow-up. Present study only observed osteogenesis in few patients who sustained type B/C intracapsular condylar fractures during their follow-up. The younger the patient was, the longer the follow-up time was, and the higher the possibility of new bone formation was. No correlation was found between the amount of osteogenesis and follow-up time, the amount of osteogenesis was generally small, and no patient could form a new condyle head similar to the normal (or original) condyle head. Condylar hypertrophy only occurred in children. Four patients developed temporomandibular joint ankylosis. CONCLUSIONS: Removal of fracture fragments is an alternative treatment option for patients who sustained comminuted or small pieces of fracture or in extremely difficult operations.

Exogenous adenosine activates A2A adenosine receptor to inhibit RANKL-induced osteoclastogenesis via AP-1 pathway to facilitate bone repair.

BACKGROUND: Adenosine is a purine nucleoside involved in regulating bone homeostasis through binding to A1, A2A, A2B, and A3 adenosine receptors (A1R, A2AR, A2BR, and A3R, respectively). However, the underlying mechanisms by which adenosine and receptor subtypes regulate osteoclast differentiation remain uncertain. This study aims to assess the role of exogenous adenosine and receptor subtypes in receptor activator of NF-κB ligand (RANKL)-induced osteoclast formation and explore the underlying molecular mechanisms. METHODS AND RESULTS: The nanofibrous mats incorporated with adenosine exhibited robust ability to facilitate rat critical-size calvarial defect healing with decreased number of osteoclasts. Moreover, exogenous adenosine substantially enhanced the expression of A2AR and suppressed tartrate-resistant acid phosphatase-positive osteoclast formation and expression of osteoclast-related genes Ctsk, NFATc1, MMP9, and ACP5. This enhancement and suppression could be reversed by adding an A2AR antagonist, ZM241385, in RAW264.7 cells. Finally, RNA sequencing showed that the expression of Fos-related antigen 2 (Fra2) was distinctly downregulated through stimulation of adenosine in RAW264.7 cells treated with RANKL. This downregulation was reversed by ZM241385 according to real-time PCR, Western blot, and immunofluorescence analyses. CONCLUSIONS: These findings demonstrated that exogenous adenosine binding to A2AR attenuated osteoclast differentiation via the inhibition of activating protein-1 (AP-1, including Fra2 subunit) pathway both in vitro and in vivo.

Mussel-inspired functionalization of electrospun scaffolds with polydopamine-assisted immobilization of mesenchymal stem cells-derived small extracellular vesicles for enhanced bone regeneration.

Mesenchymal stem cells-derived small extracellular vesicles (MSCs-sEV) have shown promising prospects as a cell-free strategy for bone tissue regeneration. Here, a bioactive MSCs-sEV-loaded electrospun silk fibroin/poly(ε-caprolactone) (SF/PCL) scaffold was synthesized via a mussel-inspired immobilization strategy assisted by polydopamine (pDA). This pDA modification endowed the as-prepared scaffold with high loading efficiency and sustained release profile of sEV. In addition, the fabricated composite scaffold exhibited good physiochemical, mechanical, and biocompatible properties. In vitro cellular experiments indicated that the MSCs-sEV-loaded composite scaffold promoted the adhesion and spreading of preosteoblast and endothelial cells, as well as enhanced osteogenic differentiation and angiogenic activity. In vivo experiments showed that the functionalized electrospun scaffolds promoted bone regeneration in a rat calvarial bone defect model. Results suggest that the developed MSCs-sEV-anchored pDA-modified SF/PCL electrospun scaffolds possess high application potential in bone tissue engineering owing to their powerful pro-angiogenic and -osteogenic capacities, cell-free bioactivity, and cost effectiveness.

The Combination of Concentrated Growth Factor and Adipose-Derived Stem Cell Sheet Repairs Skull Defects in Rats.

BACKGROUND: The goal of this study was to create a biomaterial which combines concentrated growth factor (CGF) with an adipose-derived stem cell (ADSC) sheet to promote the repair of skull defects in rats. METHODS: We determined the optimal concentration of CGF extract by investigating the effects of different concentrations (0, 5%, 10%, and 20%) on the proliferation and differentiation of ADSCs. Then we created a complex combining CGF with an ADSC sheet, and tested the effects on bone repair in four experimental rat groups: (A) control; (B) ADSC sheet; (C) CGF particles; (D) combination of CGF + ADSCs. Eight weeks after the procedure, osteogenesis was assessed by micro-CT and hematoxylin and eosin staining. RESULTS: We found that the concentration of CGF extract that promoted optimal ADSC proliferation and differentiation in vitro was 20%. In turn, bone regeneration was promoted the most by the combination of CGF and ADSCs. CONCLUSION: In this study, we determined the optimal ratio of CGF and ADSCs to be used in a biomaterial for bone regeneration. The resulting CGF/ADSCs complex promotes maxillofacial bone defect repair in rats.

Biomimetic Silk Fibroin Hydrogels Strengthened by Silica Nanoparticles Distributed Nanofibers Facilitate Bone Repair.

Various materials are utilized as artificial substitutes for bone repair. In this study, a silk fibroin (SF) hydrogel reinforced by short silica nanoparticles (SiNPs)-distributed-silk fibroin nanofibers (SiNPs@NFs), which exhibits a superior osteoinductive property, is fabricated for treating bone defects. SF acts as the base part of the composite scaffold to mimic the extracellular matrix (ECM), which is the organic component of a native bone. The distribution of SiNPs clusters within the composite hydrogel partially mimics the distribution of mineral crystals within the ECM. Incorporation of SiNPs@NFs enhances the mechanical properties of the composite hydrogel. In addition, the composite hydrogel provides a biocompatible microenvironment for cell adhesion, proliferation, and osteogenic differentiation in vitro. In vivo studies confirm that the successful repair is achieved with the formation of a large amount of new bone in the large-sized cranial defects that are treated with the composite hydrogel. In conclusion, the SiNPs@NFs-reinforced-hydrogel fabricated in this study has the potential for use in bone tissue engineering.

Digital Design and Application of 3D Printed Surgical Guide for Long Screw Fixation of Condylar Sagittal Fracture.

OBJECTIVE: To explore a digital solution for long screw fixation of condylar sagittal fracture, and to achieve accurate positioning of the long screw. METHODS: The CT data of the patient with condylar sagittal fracture was imported into Materialise Mimics, and the fractures were reduced by virtual surgery. The surgical guide for long screw fixation was designed in Materialise 3-matic, and then 3D printed for intraoperative assistance. RESULTS: With the help of the 3D printed surgical guide, the long screw used to fix condylar sagittal fracture was accurately positioned, which was completely consistent with the preoperative design. CONCLUSION: The digitally designed 3D printed surgical guide is an effective way to achieve accurate positioning of the long screw fixation of condylar sagittal fracture.

Maxillofacial Injuries in Pediatric Patients.

OBJECTIVE: This study aimed to evaluate and analyse the demographic characteristics and changes in maxillofacial injuries during their development in pediatric patients. METHODS: A retrospective cohort and case-control study was conducted. The sample was composed of all children (less than 10.5 years) who presented with maxillofacial injuries within a 6.5-year period (from December 2012 to April 2019). Data about age, gender, hospitalization date, mechanism of trauma, location and pattern of injuries, associated general injuries or systemic diseases, admission methods (emergency admission or not), type of anesthesia, treatment methods and hospital costs (¥) were recorded and analyzed. Data analysis included Chi-square test, Fisher exact test, and t test. Univariate and multivariate analyses were also performed. Logistic regression analysis was used to control for confounding variables. Differences at P < 0.05 were considered significant. RESULTS: A total of 643 pediatric patients were included in this study, with a boy-to-girl ratio of 1.77:1 (411 boys and 232 girls). The age range was 0.18 to 10.5 years (average of 3.23 ±â€Š1.98 years). The largest age group was patients aged 1 to 2 years (200 patients, 31.1%), followed by 2 to 3 years (139 patients, 21.6%). In the majority of patients, fall at ground level was the most common mechanism of injury (391 patients, 60.8%). In addition, 613 patients (95.3%) sustained at least maxillofacial soft-tissue injuries, while 460 (71.5%) sustained only maxillofacial soft-tissue injuries and 183 (28.5%) sustained maxillofacial fractures. Lip was the most vulnerable soft tissue to be injured (283 patients, 44.0%). Patients who sustained maxillofacial soft-tissue injuries were less prone to maxillofacial fractures than those who did not. Maxillofacial fractures were highly presented in patients with dental injuries (OR = 6.783; 95% confidence interval, 3.147-14.620; P < 0.001). Older children (> 5 years old) were at higher risk of maxillofacial fractures than younger children (≤ 5 years old, P = 0.006). The risk of maxillofacial fractures (except symphysis fractures) increased with age, especially in patients aged between 5 and 10 years. Maxillofacial soft-tissue injuries were highly distributed amongst patients aged 1 to 5 years. The number of patients who sustained only maxillofacial soft-tissue injuries gradually decreased from 2013 to 2018. Patients in emergency admission (OR = 13.375; 95% confidence interval, 1.286-139.121; P = 0.030) and treated under general anesthesia (OR = 27015.375; 95% confidence interval, 1033.046-706484.218; P < 0.001) were more prone to be treated by surgery procedure. Patients with facial fractures were less frequent to be treated by surgery procedure (OR = 0.006; 95% confidence interval, 0.000-0.575; P = 0.028); however, the mandibular symphysis (OR = 18.141; 95% confidence interval, 2.860-115.069; P = 0.002) or body fractures (OR = 71.583; 95% confidence interval, 2.358-2172.879; P = 0.014) were highly treated by surgery procedure. CONCLUSIONS: Maxillofacial fractures in pediatric patients were significantly related to age, etiology, maxillofacial soft-tissue injury, dental injury and other general injuries. Older pediatric patients were at higher risk of maxillofacial fractures (except symphysis fractures) and lower risk of maxillofacial soft-tissue injuries than younger pediatric patients. Patients in emergency admission, fractures of the symphysis or body, and treated under general anesthesia were the main reasons for surgical management.

Restoration of Ramus Height in Child Patients With Extracapsular Condylar Fractures: Is This Mission Almost Impossible to Accomplish?

OBJECTIVE: This study aimed to assess whether ramus height is restored in children with extracapsular condylar fractures treated by conservative or surgery procedures. METHODS: The sample consisted of 35 children (collected consecutively) less than 12 years old who presented with extracapsular condylar fractures and treated within an 8-year period (June 2011 to April 2019). Data on the age, gender, date of injury, mechanism of trauma, location and pattern of mandibular condylar fracture, associated injuries and treatment methods were recorded and analyzed. Ramus height restoration is the main evaluation indicator during the follow-up period. RESULTS: Within the 8-year record retrieval, the 35 children sustained 41 extracapsular condylar fractures. For the sample size, 10 (24.4%) and 31 (75.6%) had condylar neck and base fractures, respectively. Deviation and green-stick fracture were the predominant types in condylar neck and base fractures, accounting for more than 3 quarters (31, 75.6%). The majority (33, 80.5%) of patients were treated with nonsurgical treatment, and 8 (19.5%) were treated by open reduction and internal fixation (ORIF). During the follow-up period (1-1419 days, average time of 110.6 days), only 1 patient (with bilateral extracapsular condylar fractures) had their ramus height restored (follow-up period, 256 days). Most members of the ORIF group (5 of 8, 62.5%) postoperatively showed bended ramus (deviated angularly/fragment angulation). CONCLUSION: Conservative treatment could hardly restore the ramus height of children with extracapsular condylar fractures. Anatomically or totally restoring the ramus height is difficult even with the surgical treatment of ORIF; however, surgical treatment of ORIF can substantially restore the ramus height for dislocated fractures or seriously displaced fractures.

Extracapsular Condylar Fractures Treated Conservatively in Children: Mechanism of Bone Remodelling.

OBJECTIVE: This study aims to reveal the reconstruction process in pediatric patients with extracapsular condylar fractures after conservative treatment. We clarify that the "upright" position (or "recontouring" or favorable prognosis) of condyles is not a result of the anatomical reduction of the deviated condylar processes but originates from the remodeling of the skeleton. We also explore the related mechanism. METHODS: The sample consisted of 27 pediatric patients aged less than 12 years who presented with extracapsular condylar fractures and were treated conservatively within an 8-year period (June 2011-April 2019). Data on the age, gender, date of injury, mechanism of trauma, location and pattern of mandibular condylar fracture and associated injuries and treatment methods of the patients were obtained. The process of bone remodeling in condyles was also recorded and analyzed. RESULTS: The 27 children in this study sustained 33 extracapsular condylar fractures over the 8-year period of record retrieval. Amongst these fractures, 8 (24.2%) and 25 (75.8%) were condylar neck and condylar base fractures, respectively. Deviation and green-stick fractures were the predominant types and accounted for over 3 quarters of the condylar neck and base fractures (28, 84.8%), followed by dislocation fracture (3, 9.1%), displacement fracture (1, 3.0%), and non-displaced fracture (1, 3.0%). The period of follow-up ranged from 2 days to 257 days (average, 58.78 days). Only 1 patient with bilateral extracapsular condylar fractures showed vertically reconstructed condyles, which indicates an upright position of the condylar processes. One patient showed less angulation after treatment than before treatment, 1 patient revealed greater angulation after treatment than before treatment and all other patients (20 patients) showed the same angulation pre- and post-treatment. Both patients with only extracapsular condylar fractures showed no obvious deviations in dentition and facial asymmetry after their injury and treatment. The shortest and longest times observed for bone remodeling were 33 and 256 days, respectively. Children whose condylar head remained completely or at least partly inside the glenoid fossa showed satisfactory remodeling results during follow-up. Computed tomography scan during follow-up generally showed bone regeneration in the lateral condyle articular surface and the medial portion of the ascending ramus and bone resorption in the displaced direction (ie, the medial condyle head became sharp). Condylar heads displaced completely outside of the glenoid fossa showed serious shortening of the ascending ramus, and no obvious bone remodeling was observed. Only 1 patient with bilateral extracapsular condylar fractures showed a normal contour (ie, a vertically reconstructed condyle reflecting the upright position of the condylar processes) after 8 months. CONCLUSION: Stress stimulation originating from the glenoid fossa and ascending ramus of the mandible is a prerequisite for good condylar reconstruction. Conservative treatment could be carried out if the condylar head remains completely or at least partly inside the glenoid fossa. When the condylar head is dislocated completely outside the glenoid fossa, the glenoid-condylar relationship ceases to exist, joint function is lost and the height of the ascending ramus is significantly reduced. In this case, open reduction may be suitable.

Characteristic changes of traumatic dental injuries in a teaching hospital of Wuhan under transmission control measures during the COVID-19 epidemic.

BACKGROUND/AIMS: In December 2019, a novel coronavirus emerged in Wuhan City, and a retrospective analysis is necessary to provide clinicians with the characteristics of traumatic dental injuries (TDIs) during the epidemic. The aim of this study was to evaluate the changes in the characteristics of TDIs under the transmission control measures in Wuhan City utilizing an epidemiologic investigation. MATERIALS AND METHOD: In this retrospective study, epidemiologic information, including the number of patients, gender, age, and TDI parameters such as time since injury to the clinic visit, etiology, tooth location, and the type of injury was extracted from the records of patients in the hospital from two periods: period 1 (between January 23, 2020, and April 7, 2020) and period 2 (between January 23, 2019, and April 7, 2019). The data from the two periods were compared and analyzed. RESULT: A total of 158 patients were treated for TDIs (120 in 2019 and 38 in 2020). Males were more likely to suffer from TDIs than females with a ratio of 1.5:1, both in 2020 and 2019. Other than that, there were characteristic changes in TDIs during the transmission control measures in the COVID-19 epidemic, which included the number of patients, age, time since injury to the clinic visit, etiology, tooth location and the type of TDI. CONCLUSION: The transmission control measures during the COVID-19 epidemic had a significant impact on the epidemiology and etiology of TDIs in Wuhan City.

Emerging role of exosomes in craniofacial and dental applications.

Exosomes, a specific subgroup of extracellular vesicles that are secreted by cells, have been recognized as important mediators of intercellular communication. They participate in a diverse range of physiological and pathological processes. Given the capability of exosomes to carry molecular cargos and transfer bioactive components, exosome-based disease diagnosis and therapeutics have been extensively studied over the past few decades. Herein, we highlight the emerging applications of exosomes as biomarkers and therapeutic agents in the craniofacial and dental field. Moreover, we discuss the current challenges and future perspectives of exosomes in clinical applications.

Electrospinning Nanofiber-Reinforced Aerogels for the Treatment of Bone Defects.

Objective: Application of aerogels in bone tissue engineering is an emerging field, while the reports of electrospinning nanofiber-reinforced aerogels are limited. This research aimed at fabricating the nanofiber-reinforced aerogels and evaluating their physiochemical and biological properties. Approach: The chitosan (CS) aerogels incorporated with cellulose acetate (CA) and poly (ɛ-caprolactone) (PCL) nanofibers were fabricated via ball milling and freeze-drying techniques. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectrum, X-ray photoelectron spectroscopy (XPS), compressive experiment, and in vitro experiment were conducted to assess their physiochemical properties and biological behavior. Results: The SEM examination showed that satisfying morphology was attained in the CA/PCL/CS aerogels with incorporation of CA/PCL nanofibers and CS solution. The results of FT-IR and XPS indicated the perfect incorporation of CA, PCL, and CS. A compressive experiment confirmed that the CA/PCL/CS aerogels enhanced the compressive modulus of the pure CS aerogel. For in vitro experiment, the CA/PCL/CS composite scaffolds were proven to possess better cytocompatibility compared with the pure CS. Also, cells on the CA/PCL/CS showed well-extended morphology and could infiltrate into a porous scaffold. Furthermore, confocal experiment revealed that the CA/PCL/CS could also promote the osteogenic differentiation of MC3T3-E1 cells. Innovation: This study fabricated the nanofiber-reinforced aerogels mainly to optimize the cell/material interaction of the pure CS scaffold. Conclusion: The CA/PCL nanofibers not only improved the mechanical property of the CS aerogel to some extent but also facilitated cell adhesion and osteogenic differentiation. Thus, it could be considered a promising candidate for bone tissue engineering.