Porphyromonas gingivalis OMVs promoting endothelial dysfunction via the STING pathway in periodontitis.

OBJECTIVE: This study aimed to assess the effects of Porphyromonas gingivalis outer membrane vesicles (Pg-OMVs) in chronic periodontitis and explore the underlying mechanism involved. METHODS: In vitro, Pg-OMVs were incubated with Ea.hy926 (vessel endothelial cells, ECs) to evaluate their effects on endothelial functions and to investigate the underlying mechanism. The effects of endothelial dysfunction on MG63 osteoblast-like cells were verified using an indirect co-culture method. For in vivo studies, micro-CT was conducted to identify alveolar bone mass. Immunofluorescence staining was conducted to confirm the levels of stimulator of interferon genes (STING) in the blood vessel and the number of Runx2+ cells around the alveolar bone. RESULTS: Pg-OMVs were endocytosed by ECs, leading to endothelial dysfunction. The cGAS-STING-TBK1 pathway was activated in ECs, which subsequently inhibited MG63 migration and early osteogenesis differentiation. In vivo, Pg-OMVs promoted alveolar bone resorption, increased STING levels in the blood vessel, and decreased Runx2+ cells around the alveolar bone. CONCLUSIONS: Pg-OMVs caused endothelial dysfunction and activated the cGAS-STING-TBK1 signal cascade in ECs, thereby impairing ECs-mediated osteogenesis. Furthermore, Pg-OMVs aggregated alveolar bone loss and altered the blood vessel-mediated osteogenesis with elevated STING.

Investigating oral microbiome profiles in patients with cleft lip and palate compared with the healthy control.

BACKGROUND: Patients with cleft lip and palate (CLP) have an oronasal communication differed from the closed state in healthy individuals, leading to a unique oral microbiome. This study aimed to determine if variances in the oral microbiota persist among CLP patients who have received treatments for the closure of these fistulas compared to the microbiota of healthy individuals. METHODS: Saliva samples were collected from a cohort comprising 28 CLP patients (CLP group) and 30 healthy controls (HC group). Utilizing 16S rRNA sequencing on the Illumina NovaSeq platform, we conducted a comprehensive analysis of the diversity and composition of the oral microbiota. RESULTS: The analysis of the microbiota in the saliva samples revealed a total of 23 microbial phyla, 38 classes, 111 orders, 184 families, 327 genera and 612 species. The alpha diversity with microbial abundance and evenness indicated the significant difference between the CLP and HC groups. Principal coordinate analysis (PCoA) and the ADONIS test further supported the presence of distinct microorganisms between the two groups. The CLP group displayed elevated abundances of Neisseria, Haemophilus, Porphyromonas, and Granulicatella, as indicated by LefSe analysis. Conversely, Rothia, Veillonella, and Pauljensenia exhibited significant reductions in abundance in the CLP group. The results of the PICRUSt analysis indicated significant differences in the relative abundance of 25 KEGG pathways within the CLP group. Through Spearman correlation analysis, strong associations between Rothia, Veillonella, and Pauljensenia and 25 functional pathways linked to CLP were identified. CONCLUSION: Findings of this study offer a thorough comprehension of the microbiome profiles of CLP patients after the restoration of oronasal structure and are anticipated to present innovative concepts for the treatment of CLP.

Descending serotonergic modulation from rostral ventromedial medulla to spinal trigeminal nucleus is involved in experimental occlusal interference-induced chronic orofacial hyperalgesia.

BACKGROUND: Dental treatment associated with unadaptable occlusal alteration can cause chronic primary myofascial orofacial pain. The serotonin (5-HT) pathway from the rostral ventromedial medulla (RVM) exerts descending modulation on nociceptive transmission in the spinal trigeminal nucleus (Sp5) and facilitates chronic pain. The aim of this study was to investigate whether descending 5-HT modulation from the RVM to the Sp5 is involved in the maintenance of primary myofascial orofacial hyperalgesia after persistent experimental occlusal interference (PEOI) or after delayed removal of experimental occlusal interference (REOI). METHODS: Expressions of 5-HT3A and 5-HT3B receptor subtypes in the Sp5 were assessed by immunofluorescence staining and Western blotting. The release and metabolism of 5-HT in the Sp5 were measured by high-performance liquid chromatography. Changes in the pain behavior of these rats were examined after specific pharmacologic antagonism of the 5-HT3 receptor, chemogenetic manipulation of the RVM 5-HT neurons, or selective down-regulation of 5-HT synthesis in the RVM. RESULTS: Upregulation of the 5-HT3B receptor subtype in the Sp5 was found in REOI and PEOI rats. The concentration of 5-HT in Sp5 increased significantly only in REOI rats. Intrathecal administration of Y-25130 (a selective 5-HT3 receptor antagonist) dose-dependently reversed the hyperalgesia in REOI rats but only transiently reversed the hyperalgesia in PEOI rats. Chemogenetic inhibition of the RVM 5-HT neurons reversed the hyperalgesia in REOI rats; selective down-regulation of 5-HT in advance also prevented the development of hyperalgesia in REOI rats; the above two manipulations did not affect the hyperalgesia in PEOI rats. However, chemogenetic activation of the RVM 5-HT neurons exacerbated the hyperalgesia both in REOI and PEOI rats. CONCLUSIONS: These results provide several lines of evidence that the descending pathway from 5-HT neurons in the RVM to 5-HT3 receptors in the Sp5, plays an important role in facilitating the maintained orofacial hyperalgesia after delayed EOI removal, but has a limited role in that after persistent EOI.

A three-dimensional printed assembled sleeveless guide system for fiber-post removal.

This report describes a technique to develop a three-dimensional printed assembled sleeveless guide system to aid the fiber-post removal in a safe and efficient way. The surface and volume data of the dentition containing the targeted tooth were acquired with optical scanners and cone-beam computed tomography. The virtual path of the fiber-post removal was determined and integrated with a guide prototype with a cylindrical passage. The prototype data was split into two separate parts, combined with the matched pin and jack structures to facilitate the assembly. A guide tube was generated based on the axis of the cylindrical passage, split into three units, and combined with the previously processed data with connectors to form the finalized guide system. The adaptor for the head of handpiece was designed to facilitate the guidance. All the finalized data were printed with titanium alloy. The fiber-post of the upper right central incisor was successfully removed with the aid of this assembled sleeveless guide system that guides the handpiece rather than the rotary instrument.

Occlusal disharmony and chronic oro-facial pain: from clinical observation to animal study.

BACKGROUND: Occlusion can be viewed as the most sensitive susceptor of the central nervous system in the oro-facial region. Its inalienable relationships to the temporomandibular joint, the muscles, the stomatognathic system and even the central nervous system are self-evident. Almost all the dental treatments inevitably change the occlusion, potentially or actually, locally or extensively, and immediately or gradually. OBJECTIVE: The objective of this study was to present a narrative literature on occlusal disharmony and chronic oro-facial pain. METHODS: Literature reviews focusing on clinical studies about the relationship between occlusal disharmony and myofascial oro-facial pain, and related preclinical studies about the animal models of, as well as the peripheral and central mechanisms underlying this condition related to, occlusal disharmony were used as starting point and guidelines to describe the topics mentioned. A search of the PubMed database was performed mainly with the following search terms: "occlusion," "occlusal interference," "occlusal disharmony," "occlusal change," "oro-facial pain" and "myofascial pain." RESULTS: Relevant literature from the past 70 years until the present day was meticulously studied. The literature review together with three related characteristic clinical cases revealed an intimate association between occlusal disharmony and chronic oro-facial pain, involving pathological changes, extending from the peripheral tissues to the central nervous system. The patients suffered from psychological distress, sleep disturbance and poor life quality. CONCLUSION: Occlusal disharmony-related oro-facial pain is a clinical problem that deserves attention, although there are no universally accepted clinical protocols. The existing literature provides some constructive suggestions, but further research is needed.

Comparison of psychological states and oral health-related quality of life of patients with differing severity of temporomandibular disorders.

BACKGROUND: Studies on temporomandibular disorder (TMD) severity in patient populations are scarce. OBJECTIVES: This study sought to compare the psychological states and oral health-related quality of life (OHRQoL) among patients with differing TMD severity. METHODS: Adult patients (≥18 years old) with and without (controls) TMDs were recruited from the TMD/oro-facial pain centre and prosthodontics department, respectively. The presence and severity of TMDs were established with the Fonseca Anamnestic Index (FAI), and TMD diagnoses were confirmed with the Diagnostic Criteria for TMDs (DC/TMD). Psychological states and OHRQoL were examined with the Depression, Anxiety, Stress Scales-21 (DASS-21) and Oral Health Impact Profile for TMDs (OHIP-TMD). Data were subjected to chi-square, Kruskal-Wallis/Mann-Whitney U tests and Spearman's correlation (α = .05). RESULTS: A total of 961 participants with a mean age of 32.99 ± 13.14 years (71.19% women) were assessed. Frequencies of the various TMD categories were as follows: no TMD/controls (12.07%), mild TMD (24.56%), moderate TMD (40.37%) and severe TMD (23.00%). The three most common TMD-related symptoms were TMJ noises, mouth opening difficulty and muscle pain. Participants with moderate/severe TMD presented a higher proportion of intra-articular and/or combined disorders. They reported significantly higher levels of depression, anxiety, stress and poorer OHRQoL than their counterparts with no/mild TMD (p < .001). Moderate-to-strong correlations were observed between FAI and DASS-21/OHIP-TMD scores (rs = 0.42-0.72). CONCLUSIONS: Patients with moderate/severe TMD had significantly higher levels of psychological disturbance and poorer OHRQoL. As OHRQoL and psychological states are correlated, psychological well-being must be considered when managing patients with moderate/severe TMDs.

Astrocytes in the rostral ventromedial medulla contribute to the maintenance of oro-facial hyperalgesia induced by late removal of dental occlusal interference.

BACKGROUND: Astrocytes in the rostral ventromedial medulla (RVM) contribute to descending pain modulation, but their role in oro-facial pain induced by persistent experimental dental occlusal interference (PEOI) or following EOI removal (REOI) is unknown. OBJECTIVE: To explore the involvement of RVM astrocytes in PEOI-induced oro-facial hyperalgesia or its maintenance following REOI. METHODS: Male rats were randomly assigned into five groups: sham-EOI, postoperative day 6 and 14 of PEOI (PEOI 6 d and PEOI 14 d), postoperative day 6 following REOI on day 3 (REOI 3 d) and postoperative day 14 following REOI on day 8 (REOI 8 d). The nociceptive head withdrawal threshold (HWT) and activities of RVM ON- or OFF-cells were recorded before and after intra-RVM astrocyte gap junction blocker carbenoxolone (CBX) microinjection. RVM astrocytes were labelled immunohistochemically with glial fibrillary acidic protein (GFAP) and analysed semi-quantitatively. RESULTS: Persistent experimental dental occlusal interference-induced oro-facial hyperalgesia, as reflected in decreased HWTs, was partially inhibited by REOI at day 3 but not at day 8 after EOI placement. Increased GFAP-staining area occurred only in REOI 8 d group in which CBX could inhibit the maintained hyperalgesia; CBX was ineffective in inhibiting hyperalgesia in PEOI 14 d group. OFF-cell activities showed no change, but the spontaneous activity and responses of ON-cells were significantly enhanced that could be suppressed by CBX in REOI 8 d group. CONCLUSION: Rostral ventromedial medulla astrocytes may not participate in PEOI-induced oro-facial hyperalgesia or hyperalgesia inhibition by early REOI but are involved in the maintenance of oro-facial hyperalgesia by late REOI.

A Digital Technique to Fabricate Segmental Individual Tooth Trays for Making an Impression of Multiple Crown Preparations.

A digital technique is described for designing and fabricating segmental individual tooth trays that can be used to make an impression of multiple preparations with high accuracy and efficiency. A digital model of prepared dentition was acquired. The segmental individual tooth trays with retention attachments and tissue stops were designed and 3D printed with light-polymerizing resin. The segmental impression of each section of the prepared dentition was made with the corresponding individual tooth tray loaded with the impression material. A final overall impression was made to pick up the segmental individual tooth trays with a full arch tray.

Anti-inflammatory potential of simvastatin loaded nanoliposomes in 2D and 3D foam cell models.

Atherosclerosis is a multifactorial disease triggered and sustained by risk factors such as high cholesterol, high blood pressure and unhealthy lifestyle. Inflammation plays a pivotal role in atherosclerosis pathogenesis. In this study, we developed a simvastatin (STAT) loaded nanoliposomal formulation (LIPOSTAT) which can deliver the drug into atherosclerotic plaque, when administered intravenously. This formulation is easily prepared, stable, and biocompatible with minimal burst release for effective drug delivery. 2D and 3D in vitro models were examined towards anti-inflammatory effects of STAT, both free and in combination with liposomes. LIPOSTAT induced greater cholesterol efflux in the 2D foam cells and significantly reduced inflammation in both 2D and 3D models. LIPOSTAT alleviated inflammation by reducing the secretion of early and late phase pro-inflammatory cytokines, monocyte adherence marker, and lipid accumulation cytokines. Additionally, the 3D foam cell spheroid model is a convenient and practical approach in testing various anti-atherosclerotic drugs without the need for human tissue.

Effect of Capecitabine Maintenance Therapy Using Lower Dosage and Higher Frequency vs Observation on Disease-Free Survival Among Patients With Early-Stage Triple-Negative Breast Cancer Who Had Received Standard Treatment: The SYSUCC-001 Randomized Clinical Trial.

Importance: Among all subtypes of breast cancer, triple-negative breast cancer has a relatively high relapse rate and poor outcome after standard treatment. Effective strategies to reduce the risk of relapse and death are needed. Objective: To evaluate the efficacy and adverse effects of low-dose capecitabine maintenance after standard adjuvant chemotherapy in early-stage triple-negative breast cancer. Design, Setting, and Participants: Randomized clinical trial conducted at 13 academic centers and clinical sites in China from April 2010 to December 2016 and final date of follow-up was April 30, 2020. Patients (n = 443) had early-stage triple-negative breast cancer and had completed standard adjuvant chemotherapy. Interventions: Eligible patients were randomized 1:1 to receive capecitabine (n = 222) at a dose of 650 mg/m2 twice a day by mouth for 1 year without interruption or to observation (n = 221) after completion of standard adjuvant chemotherapy. Main Outcomes and Measures: The primary end point was disease-free survival. Secondary end points included distant disease-free survival, overall survival, locoregional recurrence-free survival, and adverse events. Results: Among 443 women who were randomized, 434 were included in the full analysis set (mean [SD] age, 46 [9.9] years; T1/T2 stage, 93.1%; node-negative, 61.8%) (98.0% completed the trial). After a median follow-up of 61 months (interquartile range, 44-82), 94 events were observed, including 38 events (37 recurrences and 32 deaths) in the capecitabine group and 56 events (56 recurrences and 40 deaths) in the observation group. The estimated 5-year disease-free survival was 82.8% in the capecitabine group and 73.0% in the observation group (hazard ratio [HR] for risk of recurrence or death, 0.64 [95% CI, 0.42-0.95]; P = .03). In the capecitabine group vs the observation group, the estimated 5-year distant disease-free survival was 85.8% vs 75.8% (HR for risk of distant metastasis or death, 0.60 [95% CI, 0.38-0.92]; P = .02), the estimated 5-year overall survival was 85.5% vs 81.3% (HR for risk of death, 0.75 [95% CI, 0.47-1.19]; P = .22), and the estimated 5-year locoregional recurrence-free survival was 85.0% vs 80.8% (HR for risk of locoregional recurrence or death, 0.72 [95% CI, 0.46-1.13]; P = .15). The most common capecitabine-related adverse event was hand-foot syndrome (45.2%), with 7.7% of patients experiencing a grade 3 event. Conclusions and Relevance: Among women with early-stage triple-negative breast cancer who received standard adjuvant treatment, low-dose capecitabine maintenance therapy for 1 year, compared with observation, resulted in significantly improved 5-year disease-free survival. Trial Registration: ClinicalTrials.gov Identifier: NCT01112826.

17ß-Estradiol Exacerbated Experimental Occlusal Interference-Induced Chronic Masseter Hyperalgesia by Increasing the Neuronal Excitability and TRPV1 Function of Trigeminal Ganglion in Ovariectomized Rats.

Pain symptoms in temporomandibular disorders (TMD) predominantly affect reproductive women, suggesting that estrogen regulates pain perception. However, how estrogen contributes to chronic TMD pain remains largely unclear. In the present study, we performed behavioral tests, electrophysiology, Western blot and immunofluorescence to investigate the role and underlying mechanisms of estrogen in dental experimental occlusal interference (EOI)-induced chronic masseter mechanical hyperalgesia in rats. We found that long-term 17ß-estradiol (E2) replacement exacerbated EOI-induced masseter hyperalgesia in a dose-dependent manner in ovariectomized (OVX) rats. Whole-cell patch-clamp recordings demonstrated that E2 (100 nM) treatment enhanced the excitability of isolated trigeminal ganglion (TG) neurons in OVX and OVX EOI rats, and EOI increased the functional expression of transient receptor potential vanilloid-1 (TRPV1). In addition, E2 replacement upregulated the protein expression of TRPV1 in EOI-treated OVX rats. Importantly, intraganglionic administration of the TRPV1 antagonist AMG-9810 strongly attenuated the facilitatory effect of E2 on EOI-induced masseter mechanical sensitivity. These results demonstrate that E2 exacerbated EOI-induced chronic masseter mechanical hyperalgesia by increasing TG neuronal excitability and TRPV1 function. Our study helps to elucidate the E2 actions in chronic myogenic TMD pain and may provide new therapeutic targets for relieving estrogen-sensitive pain.

Improving the quality of preclinical simulation training for dental students using a new digital real-time evaluation system.

BACKGROUND: With the rapid development of technology, traditional dental education has undergone a transition with the active incorporation of digital technology into curricula. DCARER is a recently developed digital real-time evaluation system for the digital assessment of student preclinical simulation practice performance. The system provides supplementary feedback on process analysis in addition to an objective final result. This study evaluated the grading validity of the DCARER system and its effect on dental preclinical practice skills training. METHODS: Seventy-three residents of Grade 2018, all of whom had completed their 3-year term residencies in standardised and systematic training, were recruited into this study to examine the system's grading validity. All performed crown preparations with the adoption of the DCARER system, which generated both process and final scores. Three experts gave their own grade anonymously according to the final work. The differences between the digital system and the expert scores were analysed. In addition, 60 dental students in Grade 4 and 10 dental faculty members were randomly divided into traditional and digital groups. The students in the traditional group prepared the tooth with the guidance of supervisors, whilst the digital group used the DCARER system. After the class, the students' tooth preparations were scored by the same three experts in a blinded manner. The students and faculty members completed two different sets of questionnaires to evaluate the effects of teaching, acceptance, satisfaction, and evaluation accuracy of the digital system and the traditional method. RESULTS: The grading validity assessment showed no significant difference between the tooth preparation scores given by the DCARER system and the experts (P> .05). The unique process scores given by the DCARER system were weakly correlated with the final scores given by both the digital system and the experts. The main characteristics of the 60 students and 10 faculty members were homogeneous at baseline (P> .05). The tooth preparations of the traditional group scored significantly lower than those of the digital group (P < .01). More students in the digital group (93.3%) believed the judgement to be objective than in the traditional group (73.3%). All students guided by the DCARER system (100%) and 80% of students taught in a traditional manner felt that the assessment reinforced the learning process. Faculty members reported that use of the digital system did not significantly increase their workload and reinforced the learning process for the internship. CONCLUSION: The results presented here indicate the validity of grading using the digital real-time evaluation system. Students and faculty could benefit from application of the system in tooth preparation practice, which may provide effective clinical interaction training for dental education.

Effect of a Standardized Training with Digital Evaluation on the Improvement of Prosthodontic Faculty's Performance in Crown Preparation: A Pre-Post Design.

PURPOSE: Standardized crown preparation is an important competency for prosthodontic faculty especially when they take on the dual role of clinician and clinical teacher. Effects of faculty training for enhancing crown preparation competency are seldom reported. This study aimed to analyze the impact of a standardized training workshop with digital evaluation on the dental faculty's performance in crown preparation. MATERIALS AND METHODS: The digitally evaluated grades of anterior (the maxillary right central incisor) and posterior (the mandibular left first molar) tooth preparations made by 76 participants who accomplished all six training tasks were collected, including off-site and on-site exercises before the didactic lecture and live demonstration, three rounds of practices with digital feedback, and a final test. Grades of preparations performed in the on-site exercise were adopted as pre-training scores, and those in the final test as post-training scores. Total scores and marks deducted for the parameters including amount of reduction, margin line, and taper were compared among each training task. RESULTS: The post-training scores of both anterior and posterior tooth preparations increased significantly more than the pre-training scores. The average increased score proportion was 22.95% ± 4.17% for anterior tooth preparations, and 21.78% ± 3.68% for posterior tooth preparations. For anterior tooth preparations, total scores and the parameters except taper significantly improved in the first practice and maintained the same level for the next sessions. Total scores and all parameters for posterior tooth preparations exhibited continual improvement during the training process. CONCLUSION: Standardized training can further improve dental faculty's crown preparation performance in a moderate way. Individual design for crown preparation training can be considered based on different tooth positions. Providing such training will aid the calibration of clinical teaching behavior and the elevation of clinical operative standards for prosthodontic faculty.

[Influence of the occlusal interference time on masticatory muscle mechanical hyperalgesia in rats].

OBJECTIVE: To investigate the relationship between the removal time of 0.2 mm occlusal interference and the recovery of masticatory muscle mechanical hyperalgesia in rats. METHODS: Forty male Sprague-Dawley rats (200-220 g) were randomly assigned to eight groups, with five rats in each group: (1) naive group: these rats were anesthetized and their mouths were forced open for about 5 min (the same duration as the other groups), but restorations were not applied; (2) sham-occlusal interference control group: bands were bonded to the right maxillary first molars which did not interfere with occlusion; (3)occlusal interference group: 0.2 mm thick crowns were bonded to the right maxillary first molars; (4) 2, 3, 4, 5, and 6 d removal of occlusal interference groups: 0.2 mm thick crowns were bonded to the right maxillary first molars and removed on days 2, 3, 4, 5, and 6. The naive group and sham-occlusal interference control group were control groups. The other groups were experimental groups. Bilateral masticatory muscle mechanical withdrawal thresholds were tested on pre-application days 1, 2, and 3, and on post-application days 1, 3, 5, 7, 10, 14, 21 and 28. The rats were weighed on pre-application day 1 and on post-application days 1, 2, 3, 4, 5, 6, and 7. RESULTS: Between the naive group and the sham-occlusal interference control group, there was no significant difference in the masticatory muscle mechanical withdrawal threshold of bilateral temporalis and masseters at each time point. No significant difference was detected between the contralateral side and ipsilateral side in experimental groups (P>0.05). In the 2, 3, 4, and 5 d removal of occlusal interference groups, the masticatory muscle mechanical withdrawal thresholds decreased after occlusal interference and increased after removal of the crowns and recovered to the baseline on days 7, 10, 14, and 14, respectively [the masticatory muscle mechanical withdrawal thresholds of right masseter muscle were (137.46 ± 2.08) g, (139.02 ± 2.11) g, (140.40 ± 0.98) g, (138.95 ± 0.98) g, respectively]. In the 6 d removal of occlusal interference group, the masticatory muscle mechanical withdrawal threshold increased after removal of the crowns and became stable since day 14. There was a significant difference between the 6 d removal of occlusal interference group and the sham-occlusal interference group on day 28 (P<0.05), the masticatory muscle mechanical withdrawal thresholds of right masseter muscle were (131.24 ± 0.76) g and (141.34 ± 1.43) g, respectively. CONCLUSION: After removal of the 0.2 mm thick crown within 5 days, the mechanical hyperalgesia of the rats could reverse completely. The mechanical hyperalgesia of the rats could only be relieved, but not reverse completely after removal of the 0.2 mm thick crown on day 6. As the time went on, even minor occlusal interference could cause irreversible mechanical hyperalgesia of masticatory muscles. This study suggested that occlusal interference caused by dental treatment should be eliminated as soon as possible, to avoid irreversible orofacial pain.

Near-infrared light responsive multi-compartmental hydrogel particles synthesized through droplets assembly induced by superhydrophobic surface.

Light-responsive hydrogel particles with multi-compartmental structure are useful for applications in microreactors, drug delivery and tissue engineering because of their remotely-triggerable releasing ability and combinational functionalities. The current methods of synthesizing multi-compartmental hydrogel particles typically involve multi-step interrupted gelation of polysaccharides or complicated microfluidic procedures with limited throughput. In this study, a two-step sequential gelation process is developed to produce agarose/alginate double network multi-compartmental hydrogel particles using droplets assemblies induced by superhydrophobic surface as templates. The agarose/alginate double network multi-compartmental hydrogel particles can be formed with diverse hierarchical structures showing combinational functionalities. The synthesized hydrogel particles, when loaded with polypyrrole (PPy) nanoparticles that act as photothermal nanotransducers, are demonstrated to function as near-infrared (NIR) light triggerable and deformation-free hydrogel materials. Periodic NIR laser switching is applied to stimulate these hydrogel particles, and pulsatile release profiles are collected. Compared with massive reagents released from single-compartmental hydrogel particles, more regulated release profiles of the multi-compartmental hydrogel particles are observed.

In vitro investigation of the effect of plasticizers on the blood compatibility of medical grade plasticized poly (vinyl chloride).

This paper reports the results of an in vitro investigation into the blood response of medical grade poly (vinyl chloride) (PVC), and two types of plasticized PVC in tubing or sheet form, with di-(2-ethylhexyl)phthalate (DEHP) and di(isononyl) cyclohexane-1,2-dicarboxylate (HEXAMOLL(®) DINCH) as plasticizer, were selected for assessment of complement activation, coagulation system and platelet activation. The results of the study show that not only the plasticizers at PVC surface have an influence on complement activation, but also the incubation condition such as incubation time and the diameter of PVC tubing. Under static status, C3a, C5a and SC5b-9 concentration in the blood were higher after contacting with PVC plasticized with DEHP (PVC1) than after contacting with PVC plasticized with DINCH (PVC2). However, under dynamic circulation, the results were totally converse, which may be due to smaller diameter and higher shear rate of PVC2. In addition, there was a significant increase of activated partial thrombin time (APTT) and decrease of FIX concentration after plasma contacting with the PVC tubing, which indicated that the intrinsic pathway may be impacted when blood contacted with PVC tubing. However, there was no significant difference of APTT, FIX concentration and CD62p expression rate between the two materials. Moreover, the migration in the DINCH system was considerably lower than for DEHP, which indicates that DINCH could be a promising alterative plasticizer of DEHP.

Accuracy of a 3D printed sleeveless guide system used for fiber post removal: An in vitro study.

OBJECTIVES: The removal of fiber post is often a challenging task. A 3D printed assembled sleeveless system that guides the head of the handpiece instead of the drill was developed to address this issue. This study aimed to evaluate the accuracy of this novel guide system using an in vitro approach. METHODS: A standard maxillary typodont was digitized. The right first molar, the right central incisor, the left first premolar, and the left second molar in the digitized dentition were virtually crown-amputated. Four cylinders (diameter: 6 mm, height: 12 mm) were positioned along the directions of the main roots of these teeth to establish the virtual test model. Ten copies of the test model were printed using light-polymerizing resin. Four assembled sleeveless guide systems targeting the cylindrical axes were designed and printed using titanium alloy. One senior prosthodontist performed the drilling task targeting each cylindrical axis aided by the guide system or freehand (20 teeth each). The drilled models were scanned. The coordinates of the centers of all perforations and circular bases on the coronal and apical surfaces were obtained. The linear and angular deviations between the actual drilling path and the cylindrical axis for each tooth were calculated and analyzed. RESULTS: The guided group exhibited significantly smaller linear and angular deviations than the freehand group (coronal linear deviation: 0.19 ± 0.09 mm vs. 0.35 ± 0.18 mm, p = 0.0012; apical linear deviation: 0.54 ± 0.19 mm vs. 1.71 ± 0.51 mm, p < 0.001; angular deviation: 2.67 ± 1.07° vs. 8.48 ± 2.86°, p < 0.001). CONCLUSION: The accuracy of the 3D printed assembled sleeveless guide system used for fiber post removal is superior to that of the freehand method within the limits of an in vitro design. CLINICAL SIGNIFICANCE: For the removal of fiber posts, the present 3D printed sleeveless guide system can provide better accuracy that the conventional freehand method. This may justify the diffusion of the guided technique for fiber post removal.

An in situ grown ultrathin and robust protein nanocoating for mitigating thromboembolic issues associated with cardiovascular medical devices.

Thromboembolism, arising from the utilization of cardiovascular medical devices, remains a prevalent issue entailing substantial morbidity and mortality. Despite the proposal of various surface modification strategies, each approach possesses inherent limitations and drawbacks. Herein, we propose a novel approach for the in situ growth of nanocoatings on various material surfaces through the cooperative assembly of silk fibroin (SF) and lysozyme. The intrinsic in situ growth characteristic enables the nanocoatings to achieve stable and uniform adherence to diverse substrate surfaces, including the inner surface of intravascular catheters, to redefine the surface properties of the material. The features of the hydrophilic and negatively charged nanocoating contribute to its antithrombotic properties, as evidenced by the reduced likelihood of platelet adhesion upon modification of the ultrathin and mechanically robust coating. In vitro assessment confirms a significant reduction in blood clot formation along with the promotion of anticoagulation. Such a SF/Ly nanocoating holds substantial promise as a surface modification strategy to enhance the hemocompatibility of medical devices and other materials that come into contact with blood, particularly in situations where medical-grade materials are temporarily unavailable, thus providing a feasible alternative.

A polycationic antimicrobial and biocompatible hydrogel with microbe membrane suctioning ability.

Despite advanced sterilization and aseptic techniques, infections associated with medical implants have not been eradicated. Most present coatings cannot simultaneously fulfil the requirements of antibacterial and antifungal activity as well as biocompatibility and reusability. Here, we report an antimicrobial hydrogel based on dimethyldecylammonium chitosan (with high quaternization)-graft-poly(ethylene glycol) methacrylate (DMDC-Q-g-EM) and poly(ethylene glycol) diacrylate, which has excellent antimicrobial efficacy against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Fusarium solani. The proposed mechanism of the antimicrobial activity of the polycationic hydrogel is by attraction of sections of anionic microbial membrane into the internal nanopores of the hydrogel, like an 'anion sponge', leading to microbial membrane disruption and then microbe death. We have also demonstrated a thin uniform adherent coating of the hydrogel by simple ultraviolet immobilization. An animal study shows that DMDC-Q-g-EM hydrogel coating is biocompatible with rabbit conjunctiva and has no toxicity to the epithelial cells or the underlying stroma.

Surface modification of PBT nonwoven fabrics used for blood filtration and their blood compatibility study.

It is necessary to remove residual leukocytes to prevent the blood transfusion-related adverse reactions. This paper describes a facile approach for the surface modification of commercial PBT nonwoven fabrics (PBTNF), used for blood filtration, followed by immobilizing polyvinylpyrrolidone (PVP). The whole blood filtration results revealed that the five types of PBTNF-PVPs' leucocytes retention rates and erythrocyte recovery rates increased to 96% and 92% compared with the untreated PBTNF. The blood compatibilities results indicated that PVP modified PBTNFs have good blood compatibility, suggesting that PVP-modified PBTNF is a very promising blood filter for selective removal of leukocytes.