Characterization of a bifunctional and endolytic alginate lyase from Microbulbifer sp. ALW1 and its application in alginate oligosaccharides production from Laminaria japonica.

The diverse biological activities of alginate oligosaccharides attracted extensive exploration of alginate lyases with various substrate specificity and enzymatic properties. In this study, an alginate lyase from Microbulbifer sp. ALW1, namely AlgL7, was phylogenetically classified into the polysaccharide lyase family 7 (PL7). The conserved amino acid residues Tyr606 and His499 in AlgL7 were predicted to act as the general acid/base catalysts. The enzyme was enzymatically characterized after heterologous expression and purification in E. coli. AlgL7 displayed optimal activity at 40 °C and pH 7.0. It had good stability at temperature below 35 °C and within a pH range of 5.0-10.0. AlgL7 exhibited good stability against the reducing reagent ß-ME and the surfactants of Tween-20 and Triton X-100. The degradation profiles of alginate indicated AlgL7 was a bifunctional endolytic alginate lyase generating alginate oligosaccharides with the degrees of polymerization 2-4. The degradation products of sodium alginate exhibited stronger antioxidant activities than the untreated polysaccharide. In addition, AlgL7 could directly digest Laminaria japonica to produce alginate oligosaccharides. These characteristics of AlgL7 offer a great potential of its application in high-value utilization of brown algae resources.

Effect of photobiomodulation therapy on mini-implant stability: a systematic review and meta-analysis.

The study aimed to assess trials investigating the effect of PBMT on mini-implant stability. Electronic searches of seven databases and manual search were conducted up to May 2020. Randomized controlled trials and controlled clinical trials evaluating the effect of PBMT on mini-implant stability were included. The risks of bias of individual studies were performed using ROB 2.0 and ROBINS-I-tool based on different study design. Meta-analysis was conducted to compare mini-implant stability exposed to PBMT with control ones at different time points after implantation. Among the 518 records initially identified, seven studies were included in this study. Six studies investigated low-level laser therapy (LLLT) and one study evaluated light-emitting diode (LED) therapy. Two studies were eligible for meta-analysis, which showed that LLLT significantly improved mini-implant stability 60 days after initial implantation (MD - 3.01, 95% CI range [- 4.68, - 1.35], p = 0.0004). High energy density of LLLT began to show beneficial effect on mini-implant stability as early as 3 days after implantation, while the significant effect of low energy density displayed later than 30 days after insertion. LED therapy could improve mini-implant stability after 2 months post-insertion. In conclusion, PBMT appears to be beneficial in ameliorating mini-implant stability. High energy density of LLLT might exert more rapid effect than low energy density. More high-quality clinical trials are needed to further demonstrate PBMT' effects on orthodontic mini-implants.

Effect of clear aligners on oral health-related quality of life: A systematic review.

Clear aligners have been frequently applied in orthodontic clinic practice. However, its effect on oral health-related quality of life (OHRQoL) compared with fixed appliance treatment (FAT) remains inconclusive. This systematic review aimed to compare the impacts of clear aligner treatment (CAT) with FAT on patients' OHRQoL. Electronic searches of databases (PubMed, Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, Embase, Medline, two Chinese databases and six grey literature databases) were conducted up to July 2019. Randomized controlled trials, controlled clinical trials, cohort studies and cross-sectional studies comparing the impact of CAT and FAT on OHRQoL with validated instruments were included. Extraction of data and assessment of the risk of bias were conducted using ROBINS-I-tool, Newcastle-Ottawa Scale and ROB 2.0 based on study design. Of the 1112 records initially identified, 2 studies were included in this review. One study evaluated OHRQoL at the last debonding appointment, while the other made evaluation at the early stage of treatment. In the aspect of functional dimensions, both studies reported less eating disturbance in CAT patients than FAT ones. Based on currently limited information, the effect of CAT on the overall OHRQoL compared to FTA was still inconclusive. In individual dimensions, however, weak evidence supported that CAT might cause less eating disturbance than FAT. More high-quality clinical trials using validated OHRQoL instruments are needed to draw more reliable conclusions in the effect of CAT and FAT on OHRQoL.

Influence of orthodontic treatment with premolar extraction on the spatial position of maxillary third molars in adult patients: a retrospective cohort cone-bean computed tomography study.

BACKGROUND: Based on low-dose radiation Cone-bean computed tomography (CBCT) images, This study aims to establish a space coordinate system, which offers more precise and comparable evaluation on changes of maxillary third molars influenced by orthodontic treatment with premolar extraction in adults. The system suggests promising application prospect in future studies related to CBCT superimposition and evaluation for its feasibility and efficiency. METHODS: Forty-nine maxillary third molars from 27 patients (mean age, 20.78 years) were included. CBCT images were obtained before and after orthodontic treatment with premolars extracted (mean treatment duration, 31.47 months). The changes in the position, angulation, and rotation of the third molars were evaluated with a space coordinate system using four landmarks: anterior nasal spine (ANS), posterior nasal spine (PNS), left and right orbitales. RESULTS: After orthodontic treatment, the third molars moved forward (adjusted mean, 1.44 mm) (p < 0.001) and downward (adjusted mean, 2.87 mm) (p < 0.001) accompanied by outward rotation of the crowns (adjusted mean, 5.38°) (p = 0.001), while changes in angulation were insignificant. CONCLUSIONS: This was the first study to systematically investigate the spatial position change of maxillary third molars in adult patients who received orthodontic treatment with premolar extraction. During the process, maxillary third molars moved downward and forward accompanied by outward rotation of the crowns. Orthodontists should take tooth movement potential into consideration when making extraction plans.

Porous PLGA microparticles prepared with nanosized/micronized sugar particles as porogens.

The objective of this study was to explore the use of nanosized/micronized sugar particles as porogens for preparing porous poly(lactide-co-glycolide) (PLGA) microparticles by a solid-in-oil-in-water (S/O/W) solvent evaporation method. Porous PLGA microparticles containing dexamethasone were prepared with different nanosized/micronized sugars (sucrose, trehalose and lactose), types of PLGA, and osmogens (NaCl or sucrose) in the external water phase. The microparticles were characterized for morphology, thermal properties, particle size, surface area, encapsulation efficiency and drug release/swelling during release. The addition of nanosized/micronized sugar particles resulted in porous PLGA microparticles with high encapsulation efficiencies. The porosity of the microparticles was caused both by the influx of water into the polymer droplets and the encapsulation and subsequent dissolution of sugar particles during the manufacturing process. The porosity (pore size) of the microparticles and, as a result, the drug release pattern could be well controlled by the particle size and weight fraction of the sugar particles. Because of a larger inner surface area, nanosized sugar particles were more efficient porogen than micronized sugar particles to obtain porous PLGA microparticles with flexible release patterns.

Three-Dimensional Evaluation of Condylar Position and Joint Spaces Following Orthodontic Treatment With Quadruple Premolar Extractions.

This study aimed to assess the alterations in the temporomandibular joint among adult patients undergoing orthodontic treatment involving the extraction of four premolars. A cohort of 44 adults, with a mean age of 24.2 years, underwent orthodontic therapy that included quadruple premolar extractions. Cone-beam computed tomography scans were performed before and after the treatment to evaluate the temporomandibular joints. The three-dimensional assessment focused on the condylar position relative to the cranial base and the articular fossa, the axial condylar rotation, and the joint spaces. Notably, a significant posterior shift of the condyle was detected (P≤0.01), averaging a 0.41mm retraction. The posterior joint space narrowed by 0.32mm post-treatment. Additionally, a medial tilt of 0.62° in the condyle's long axis was observed in the frontal plane. No significant changes were recorded for the other condylar positions, rotations, or joint space dimensions. The findings suggest that orthodontic treatment with four premolar extractions may instigate condylar repositioning and rotation. These insights can inform refinements in treatment protocols.

Single-cell transcriptional profiling reveals immunomodulatory properties of stromal and epithelial cells in periodontal immune milieu with diabetes in rats.

Periodontitis is the sixth major complication of diabetes. Gingiva, as an important component of periodontal tissues, serves as the first defense barrier against infectious stimuli. However, relatively little is known about cellular heterogeneity and cell-specific changes in gingiva in response to diabetes-associated periodontitis. To characterize molecular changes linking diabetes with periodontitis, we profiled single-cell transcriptome analyses of a total of 45,259 cells from rat gingiva with periodontitis under normoglycemic and diabetic condition. The single-cell profiling revealed that stromal and epithelial cells of gingiva contained inflammation-related subclusters enriched in functions of immune cell recruitment. Compared to normoglycemic condition, diabetes led to a reduction in epithelial basal cells, fibroblasts and smooth muscle cells in gingiva with periodontitis. Analysis of differentially expressed genes indicated that stromal and epithelial populations were reprogrammed towards pro-inflammatory phenotypes promoting immune cell recruitment in diabetes-related periodontitis. In aspect of immune cells, diabetes prominently enhanced neutrophil and M1 macrophage infiltration in periodontitis lesions. Cell-cell communications revealed enhanced crosstalk between stromal/epithelial cells and immune cells mediating by chemokine/chemokine receptor interplay in diabetes-associated periodontitis. Our findings deconvolved cellular heterogeneity of rat gingiva associated with periodontitis and diabetes, uncovered altered immune milieu caused by the disease, and revealed immunomodulatory functions of stromal and epithelial cells in gingival immune niche. The present study improves the understanding of the link between the diabetes and periodontitis and helps in formulating precise therapeutic strategies for diabetes-enhanced periodontitis.

A comparative study of PLGA microparticle properties loaded with micronized, nanosized or dissolved drug.

The objective of this study was to compare properties of poly(lactide-co-glycolide) (PLGA) microparticles loaded with dexamethasone or hydrocortisone in the micronized, nanosized or dissolved state. Dexamethasone and hydrocortisone were nanosized by wet bead milling. The microparticles were prepared by a solvent extraction/evaporation method and were characterized by particle size, encapsulation efficiency, drug solid-state, morphology, in vitro release and dynamic microparticle diameter changes during release. The micronized and nanosized drugs were still in crystalline form after encapsulation into PLGA microparticles with encapsulation efficiencies greater than 85 %. Encapsulating dissolved drugs resulted in lower encapsulation efficiencies (32 to 63 %) and the dissolved drug recrystallized within the PLGA matrix at a higher actual drug loading of 30 %. The order in drug release depended on the physical state of the encapsulated drug and was in the order of dissolved > nanosized > micronized drug. Interestingly, quasi-linear release profiles were obtained with 10 % nanosized dexamethasone in PLGA 502H and 503H microparticles. In conclusion, encapsulating dispersed and, in particular, nanosized drug into PLGA microparticles is a promising tool to increase the encapsulation efficiency, to maintain a stable drug solid-state and to achieve a more continuous release profile.

Detailed Correlation between Central Incisor Movement and Alveolar Bone Resorption in Adults with Orthodontic Premolar Extraction Treatment: A Retrospective Cohort CBCT Study.

Background: This study aims to explore the detailed correlation between the movement of maxillary and mandibular central incisors and alveolar bone resorption in adults who had orthodontic premolar extraction treatment. Methods: A total of 63 adult patients (mean age, 24.41 years) who received orthodontic treatment with the extraction of four first premolars were included in this study. CBCT images were obtained before and after treatment. Three-dimensional evaluations of the movement of 252 central incisors (126 maxillary and 126 mandibular incisors) and alveolar bone changes were conducted. Four points were used to describe the incisor movement: C (cusp point), R (root apex point), M (mid-point of root neck), and L (labial cementoenamel junction point). The thickness of labial and palatal alveolar bone was assessed at the crestal, mid-root, and apical levels of incisors. The results were analyzed with Spearman's correlation and multilinear regression. Results: Matching the measurements of central incisor movement and alveolar bone resorption, significant correlations could be observed. For maxillary central incisors, the labial alveolar bone resorption at the crestal level was correlated with the movement of Point L (r = 0.290, p < 0.05), and the labial alveolar bone resorption at the apical level was correlated with Point M (r = 0.387, p < 0.05). For mandibular central incisors, the labial alveolar bone resorption at the apical level was correlated with the movement of Point M (r = 0.493, p < 0.05) and R (r = 0.498, p < 0.01); the palatal alveolar bone resorption at the mid-root level with Point M (r = -0.170, p < 0.01); and the palatal alveolar bone resorption at the apical level with Point R (r = 0.177, p < 0.01). Conclusions: This study investigated the concrete correlations between central incisor movement and alveolar bone resorption in adults after orthodontic treatment with premolar extraction. It is potentially helpful for orthodontists to have a relatively accurate prediction of alveolar bone resorption based on the specific movements of central incisors and to reduce the risk of alveolar bone resorption by better adjusting the three-dimensional movement types of incisors.

Association between Psychological Status and Condylar Bony Changes in Adults: A Retrospective Survey-Based Study.

Background: This article studies the association between psychological status and condylar bony changes in adults and assesses psychological questionnaires as an indicator of potential condylar bony changes. It is meaningful because condylar bony changes, a severe subtype of TMD and big concern in orthodontic treatment, would likely be ignored in patients with few TMD symptoms, in which case, even with potential psychological problems (depression, somatization and anxiety) being noticed, orthodontists may underestimate the possibility or severity of condylar bony changes and thus may not perform relevant examinations. Methods: A total of 195 adults (145 female and 50 male) who consulted orthodontists and had clinical records were included in this study. Initial CBCT images taken before orthodontic treatment were used for observing their condylar bony changes, and a comprehensive questionnaire conducted by each adult to evaluate psychological status was collected. Age, sex, TMD symptom history, scores on Patient Health Questionnaire-9 (PHQ-9), PHQ-15 and Generalized Anxiety Disorder-7 (GAD-7), and condylar bony changes of these adults were recorded. Odds ratios (OR) and 95% confidence intervals (CIs) for identifying the independent risk factors associated with condylar bony changes were calculated with univariate and multivariate logistic regression analysis. The kappa statistic was used to assess intraobserver reliability of CBCT analysis. Results: The scores of PHQ-15 (OR: 2.088, 95% CI: 1.061−4.108, p < 0.05) and GAD-7 (OR: 2.133, 95% CI: 1.082−4.204, p < 0.05) were correlated with the condylar bony changes on CBCT. Besides, the probability of having condylar bony changes was positively correlated with the number of psychological problems concomitantly present in an adult (OR: 1.440, 95% CI: 1.10−1.867, p < 0.01). The intraobserver agreement value for CBCT analysis was substantial (κ = 0.732). Conclusions: This study found that positive PHQ-15 (somatization) and GAD-7 (anxiety) scores were associated with condylar bony changes in adults. Moreover, the number of psychological problems concomitantly present in an adult was positively associated with the probability of having condylar bony changes.

A novel biomechanical system to intrude the upper incisors and control overbite: Posterior miniscrew-assisted lever arm and 2 cases report.

RATIONALE: Overbite control is a key factor in orthodontic treatment. In some cases, incisor intrusion is essential and could be an optimal strategy for overbite control. The aim of this article was to introduce a biomechanical system called the posterior miniscrew-assisted lever arm, which is innovative in using existing posterior miniscrews to intrude the upper incisors and to control anterior overbite while simultaneously retracting the anterior teeth. Its efficiency in incisor intrusion has been proved with 2 cases. PATIENT CONCERNS: Two adult women who came for orthodontic treatment with the chief complaint of convex profile were included in this study. DIAGNOSIS: Both patients had similar malocclusions of Class II molar relationship, anterior deep overjet, and anterior deep overbite. INTERVENTIONS: Their treatment plans were to extract 4 first premolars and insert 2 maxillary posterior buccal miniscrews. After teeth aligning and leveling, en masse retraction was started in both arches. During the space-closing stage, posterior miniscrew-assisted lever arms were placed in their upper arches so as to intrude upper incisors and control the overbite. OUTCOMES: After respectively 4 months and 3 months of incisor intrusion, the anterior overbite was successfully reduced to the normal range in each patient. Cephalometric analysis and superimposition also confirmed the treatment effect of this biomechanical system on incisor intrusion. LESSONS: The posterior miniscrew-assisted lever arm is a valuable biomechanical system for intruding incisors and controlling anterior overbite.

A Novel Method to Combine Maxilla-Based Coordinate System and Mandibular Voxel-Based Superimposition with Cone-Bean Computed Tomography.

BACKGROUND: The objective of this study was to propose a method that combines a maxilla-based coordinate system and mandibular voxel-based superimposition for an accurate evaluation of mandibular structural and positional changes and a direct comparison between maxillary and mandibular structural changes with the same 3D vectors. METHODS: Mandibular voxel-based superimposition was firstly performed to reorient the mandibles and eliminate the mandibular positional changes. Then, a maxilla-based coordinate system was constructed with four maxillary skeletal landmarks (ANS, PNS, OrL and OrR). After settling the reoriented mandibles into this coordinate system, the mandibular structural changes were accurately evaluated. To assess the accuracy and reproducibility of this method, CBCT images of a skull specimen before and after orthodontic treatment (which was simulated by rearranging the skull and the mandible) were collected. Five mandibular skeletal landmarks, three mandibular dental landmarks and two mandibular measurement planes of this skull were used to evaluate the linear and angular changes in the mandibular structures. RESULTS: There were significant differences in the linear and angular measurements of the mandibular structures of the skull (p ˂ 0.05), which indicated mandibular positional changes after orthodontic treatment. After mandibular voxel-based superimposition, there were no significant differences in the linear and angular measurements of mandibular structures, which indicated that the mandibular positional changes were eliminated. The intraclass correlation coefficient (ICC) value of the inter- and intra-observer agreement of all measurements was 0.99. CONCLUSIONS: This method has proven advantages in terms of accuracy, reproducibility and validity; with this method, mandibular structural and positional changes can be accurately evaluated and maxillary and mandibular structural changes can be directly compared with same 3D vectors.

Photoregulative phase change biomaterials showing thermodynamic and mchanical stabilities.

Azobenzenes are great photochromic molecules for switching the physical properties of various materials via trans-cis isomerization. However, the UV light resulted cis-azobenzene is metastable and thermodynamically gets back to trans-azobenzene after ceasing UV irradiation, which causes an unwanted property change of azobenzene-containing materials. Additionally, thermal and mechanical conditions would accelerate this process dramatically. In this present work, a new type of azobenzene-containing surfactant is designed for the fabrication of photoresponsive phase change biomaterials. With a "locked" cis-azobenzene conformation, the resulting biomaterials could maintain their disordered state after ceasing UV light, which exhibit great resistance to thermal and piezo conditions. Interestingly, the "locked" cis-azobenzene could be unlocked by Vis light in high efficiency, which opens a new way for the design of phase change materials only responding to light. By showing stable cis-azobenzene maintained physical state, the newly fabricated biomaterials provide new potential for the construction of advanced materials, like self-healing materials, with less use of long time UV irradiation for maintaining their disordered states.

Topical vancomycin for treatment of methicillin-resistant Staphylococcus epidermidis infection in a rat spinal implant model.

STUDY DESIGN: Basic science. OBJECTIVE: Investigate the ability of local applicaiton of vancomycin, either in powder form or suspended within poly(lactic-co-glycolic acid) microspheres (MS), to treat infection using a rat spinal model. Surgical site infections (SSIs) are a serious complication after spine surgery and are associated with high morbidity and mortality and often caused my coagulase negative staphylococci. A comprehensive approach to reduce SSIs has been recommended including the use of topical vancomycin. Animal and human studies have shown improved control of infection with local compared to systemic antibiotics. METHODS: K-wires seeded with methicillin-resistant Staphylococcus epidermidis RP62A (MRSE) were treated with vancomycin powder, carboxymethylcellulose sodium salt (CMC) (microsphere carrier), vancomycin powder, blank MS or vancomycin-loaded MS for 24 or 48 h in vitro after which bacteria were enumerated. In addition, a spinal instrumentation model was developed in rats with a bacterial seeded K-wire implanted into the right side of L4 and L5. Rats underwent no treatment or were treated locally with either vancomycin powder, blank MS or vancomycin-loaded MS. After 8 weeks, the K-wire, bone, soft tissue and wire fastener were cultured and results analyzed. RESULTS: Vancomycin powder and vancomycin-loaded MS resulted in significantly fewer bacteria remaining in vitro than did CMC. Vancomycin powder- treated animals' cultures were significantly lower than all other groups (P < 0.0001) with negative culture results, except for one animal. The vancomycin-loaded MS-treated animals had lower bone bacterial counts than the controls (P < 0.0279); blank MS-treated animals had no differences in bacterial densities when compared to non-treated animals. CONCLUSION: Vancomycin powder and vancomycin-loaded MS were active against MRSE in vitro, in a rat MRSE implant model; however, vancomycin MS were inferior to the topical vancomycin powder. Vancomycin powder prevented MRSE infection in a rat spinal implant infection model.

Transcutaneous immunization via rapidly dissolvable microneedles protects against hand-foot-and-mouth disease caused by enterovirus 71.

Recent large outbreaks of hand-foot-and-mouth disease (HFMD) have seriously affected the health of young children. Enterovirus 71 (EV71) is the main causative agent of HFMD. Herein, for the first time, rapidly dissolvable microneedles (MNs) loaded with EV71 virus-like particles (VLPs) were evaluated whether they could induce robust immune responses that confer protection against EV71 infection. The characteristics of prepared MNs including hygroscopy, mechanical strength, insertion capacity, dissolution profile, skin irritation and storage stability were comprehensively assessed. EV71 VLPs remained morphologically stable during fabrication. The MNs made of sodium hyaluronate maintained their insertion ability for at least 3h even at a high relative humidity of 75%. With the aid of spring-operated applicator, EV71 MNs (approximately 500µm length) could be readily penetrated into the mouse skin in vivo, and then rapidly dissolved to release encapsulated antigen within 2min. Additionally, MNs induced slight erythema that disappeared within a few hours. More importantly, mouse immunization and virus challenge studies demonstrated that MNs immunization induced high level of antibody responses conferring full protection against lethal EV71 virus challenge that were comparable to conventional intramuscular injection, but with only 1/10th of the delivered antigen (dose sparing). Consequently, our rapidly dissolving MNs may present as an effective and promising transcutaneous immunization device for HFMD prophylaxis among children.

[RESEARCH PROGRESS OF STRATEGIES TO AUGMENT TENDON-TO-BONE HEALING].

OBJECTIVE: To summarize the application status and progress of the strategies to augment tendon-to-bone healing. METHODS: The present researches focused on augmentation of tendon-to-bone healing were extensively reviewed. RESULTS: The present strategies to augment healing of tendon-to-bone by enhancing the location environment, and increasing the cell numbers and relative growth factor. The mainly strategies include using calcium phosphate materials, biocompatible scaffolds and glue, growth factors, cell matrix, platelet-rich plasma, and periosteum. Although periosteum have been used in clinical and got some possitive effects, the others still not be used in clinical and needs further studies. CONCLUSION: There are many strategies to enhance the ability of tendon-to-bone healing, which got some positive results, but results of studies were varied. Thus, further fundamental research and clinical studies are required to achieve the best effects.

A rabbit maxillary sinus model with simultaneous customized-implant placement: Comparative microscopic analysis for the evaluation of surface-treated implants.

We describe the use of a rabbit maxillary sinus model, characterized by thin osseous tissue and low bone density, for the evaluation of surface-treated implants by histologically and histomorphometrically comparing the osseointegration patterns depending on the surface treatment methods. Twenty rabbits were randomly assigned to two groups of 10 animals, one receiving 5 × 3 mm customized implants (machined, MA or sandblasted and acid etched, SLA) placed in sinus and the other receiving implants placed in a tibia. Histological observation of the implant placed in sinus shows relatively more active new bone formation, characterized by trabecular bone pattern underneath the cortical bone in sinus as compared with that in tibia. Histomorphometric analysis in the rabbits receiving implants in a tibia, the NBIC (%) associated with the SLA surface implant was greater than that associated with the MA implant at 2 weeks (55.63 ± 8.65% vs. 47.87 ± 10.01%; P > 0.05) and at 4 weeks (61.76 ± 9.49% vs. 42.69 ± 10.97%; P < 0.05). Among rabbits receiving implants in a sinus, the NBIC (%) associated with the SLA surface implant was significantly greater than that associated with the MA surface implant both at 2 weeks (37.25 ± 7.27% vs. 20.98 ± 6.42%; P < 0.05) and at 4 weeks (48.82 ± 6.77% vs. 31.51 ± 9.14%; P < 0.05). As a result, we suggest that the maxillary sinus model is an appropriate animal model for assessing surface-treated implants and may be utilized for the evaluation of surface-treated implants in poor bone quality environment. Microsc. Res. Tech. 78:697-706, 2015.