Rational Synthesis of Functionalized Covalent Organic Frameworks via Four-Component Reaction.

The construction of function-oriented covalent organic frameworks (COFs) remains a challenge as it requires simultaneous consideration of diversified structures, robust linkage, and tailorable functionalities. Herein, we report the rational synthesis of functionalized COFs via a four-component reaction strategy. Through the four-component Debus-Radziszewski reaction, 11 N-substituted imidazole-based COFs with diversified structures were facilely constructed from readily available building blocks. By forming the N-substituted imidazole linkage, these synthesized COFs displayed ultrastability toward strong acids and base. Moreover, the four components reaction allows the rational synthesis of COFs with tailorable functionalities. As an example, the phosphonate-functionalized COF (LZU-530) was rationally constructed for the efficient adsorption of uranium(VI). The uranium(VI) uptake of LZU-530 reaches up to 95 mg·g-1 in 2 M HNO3, which is the highest uptake of the existing organic porous materials under such harsh conditions. Our results highlight the use of multicomponent reaction for the rational synthesis of robust and functionalized COFs toward targeted applications.

Effectiveness of the attachment position in molar intrusion with clear aligners: a finite element study.

OBJECTIVE: To evaluate the biomechanical effects of different attachments' position for maxillary molar intrusion with clear aligner treatment by finite element analysis. METHODS: Cone-beam computed tomography images of a patient with supra-eruption of the maxillary second molars were selected to construct three-dimensional models of the maxilla, periodontal ligaments, dentition, and clear aligner. The models were divided into four groups depending on the attachment location on the first molar: (1) no attachment (NA), (2) buccal attachment (BA), (3) palatal attachment (PA), and (4) bucco-palatal attachment (BPA). After applying an intrusion of 0.2 mm on the second molar, displacements and stress distributions of the teeth, aligner, and periodontal ligament were analyzed with the finite element software. RESULTS: All groups displayed equivalent movement patterns of aligners. The NA and BA groups showed buccal tipping of the second molar, while the PA group showed palatal tipping. The BPA group had the highest intruding value and the lowest buccal/palatal tipping value. All groups showed mesial tipping of the second molar. Stress distribution in the periodontal ligament strongly correlated with the attachment position. The BPA group showed the best stress distribution. CONCLUSION: Combined BA and PA could effectively prevent buccal and palatal tipping and showed the best efficiency in intruding the second molar. The second molar showed an unavoidable tendency to tip mesially, regardless of the attachment position.

Doping Free and Amorphous NiOx Film via UV Irradiation for Efficient Inverted Perovskite Solar Cells.

High crystallization and conductivity are always required for inorganic carrier transport materials for cheap and high-performance inverted perovskite solar cells (PSCs). High temperature and external doping are inevitably introduced and thus greatly hamper the applications of inorganic materials for mass production of flexible and tandem devices. Here, an amorphous and dopant-free inorganic material, Ni3+ -rich NiOx , is reported to be fabricated by a novel UV irradiation strategy, which is facile, easily scaled-up, and energy-saving because all the processing temperatures are below 82 â„ƒ. The as-prepared NiOx film shows highly improved conductivity and hole extraction ability. The rigid and flexible PSCs present the champion efficiencies of 22.45% and 19.7%, respectively. This work fills the gap of preparing metal oxide films at the temperature below 150 °C for inverted PSCs with the high efficiency of >22%. More importantly, this work upgrades the substantial understanding about inorganic materials to function well as efficient carrier transport layers without external doping and high crystallization.

Stem Cells from Human Exfoliated Deciduous Teeth (SHEDs) and Dental Pulp Stem Cells (DPSCs) Display a Similar Profile with Pericytes.

BACKGROUND: Pericytes play an important role in forming functional blood vessels and establishing stable and effective microcirculation, which is crucial for vascular tissue engineering. The slow ex vivo expansion rate, limited proliferative capacity, and variability of tissue-specific phenotypes would hinder experimental studies and clinical translation of primary pericytes. In this study, the angiogenic and pericyte functions of stem cells from human exfoliated deciduous teeth (SHEDs) and postnatal human dental pulp stem cells (DPSCs) were investigated. METHODS: Osteogenic and adipogenic induction assays were performed to evaluate the mesenchymal potential of SHEDs, DPSCs, and pericytes. An in vitro Matrigel angiogenesis assay was conducted to reveal the ability of SHEDs, DPSCs, and pericytes to stabilize vascular-like structures. Quantitative real-time polymerase chain reaction (RT-qPCR) was performed to evaluate mRNA expression. Flow cytometry, western blotting, and immunostaining were used to assess the protein expression. Wound healing and transwell assays were performed to evaluate the migration ability of SHEDs, DPSCs, and pericytes. RESULTS: The osteogenic and adipogenic induction assays showed that SHEDs, DPSCs, and pericytes exhibited similar stem cell characteristics. The mRNA expression levels of PDGFR-ß, α-SMA, NG2, and DEMSIN in SHEDs and DPSCs cultured in EC medium were significantly higher than those in the control groups on day 7 (P < 0.05), but significantly higher than those in the pericytes group on day 14 (P < 0.05). Flow cytometry showed that high proportions of SHEDs and DPSCs were positive for various pericyte markers on day 7. The DPSCs, SHEDs, and pericytes displayed strong migration ability; however, there was no significant difference among the groups (P > 0.05). CONCLUSION: The SHEDs and DPSCs display a profile similar to that of pericytes. Our study lays a solid theoretical foundation for the clinical use of dental pulp stem cells as a potential candidate to replace pericytes.

Pyrimidazole-Based Covalent Organic Frameworks: Integrating Functionality and Ultrastability via Isocyanide Chemistry.

Development of new chemistry to simultaneously meet the demands for topology, connectivity, and functionality is highly desired in the research area of covalent organic frameworks (COFs). We explore herein the isocyanide chemistry so as to establish a facile paradigm to integrate functionality and ultrastability in COFs. Using the representative Groebke-Blackburn-Bienaymé (GBB) reaction based on isocyanide chemistry, we are able to construct a series of pyrimidazole-based COFs in one step from isocyanide, aminopyridine, and aldehyde monomers. Diversified functionalities have been bottom-up integrated by the simple replacement of readily available 2-aminopyridine monomers. Meanwhile, the ubiquitous formation of fused imidazole rings within the frameworks has guaranteed their ultrastability. In view of the rich synthetic possibilities provided by isocyanide chemistry, we expect that this contribution opens up a new avenue toward the divergent construction of robust COFs for practical applications.

Constructing Robust Covalent Organic Frameworks via Multicomponent Reactions.

Methodology development of robust linkages is fundamentally important for the synthesis and application of covalent organic frameworks (COFs). We report herein a new strategy based on multicomponent reactions (MCRs) to construct ultrastable COFs. With the one-pot formation of five covalent bonds in each cyclic joint, a series of imidazole-linked COFs were robustly constructed through the Debus-Radziszewski MCR from three easily available components. By reaching a higher level of complexity and precision in covalent assembly, this research explores a new direction in integrating sophisticated reversible/irreversible reactions to construct crystalline porous frameworks.

[Effect of transfected EphB4 on osteogenic differentiation in stem cells from human exfoliated deciduous teeth].

PURPOSE: To evaluate the effect of stem cells from human exfoliated deciduous teeth (SHED) transfected with EphB4 gene in regulating osteogenic differentiation. METHODS: Human dental pulp tissue were harvested from extracted deciduous teeth and digested by collagenase and dispase. The SHEDs were transfected with transgenic (hEphB4-GFP) vector or empty vector (GFP-vector). Real time-polymerase chain reaction（real time-PCR） analysis and Western blot were used to detect the expression of EphB4 in SHEDs after transfection. EphB4-SHEDs and GFP-SHEDs were subjected to osteogenic induction and assessed by alkaline phosphatase(ALP) assay and Alizarin-red S staining. SPSS 16.0 software package was used for statistical analysis. RESULTS: Real time-PCR revealed that the expression of EphB4 was significantly enhanced in EphB4-SHEDs compared to GFP-SHEDs (P<0.05). The expression of EphB4 protein was significantly higher (P<0.05) in EphB4-SHEDs compared to GFP-SHEDs. ALP assay and Alizarin-red S staining demonstrated higher ALP activity and increased mineralization with EphB4-SHEDs. CONCLUSIONS: The results indicate that transgenic expression of EphB4 in SHEDs could promote osteogenic differentiation.

[The mechanism of corticotomy accelerating orthodontic tooth movement in SD rats].

PURPOSE: To study the influences of corticotomy on orthodontic tooth movement (OTM) and the underlying mechanism in rats. METHODS: Forty-eight female Sprague-Dawley rats were randomly assigned to corticotomy group (Cort, 24 rats) or sham-corticotomy group (Sham, 24 rats). All rats were subjected OTM after corticotomy or sham surgery. 6 rats of each group were sacrificed at 0, 1, 3 and 7 day of OTM. OTM were measured with an electronic digital caliper. Osteoclasts were counted in pressure side with TRAP. RANKL were measure by IHC at pressure side. The data were analyzed with SPSS 16.0 software package. RESULTS: OTM at the 1 and 7 day in Cort group increased compared with sham group. Number of TRAP positive osteoclasts in pressure side increased in Cort group at the 3 and 7 day. Expression of RANKL in pressure side also increased in Cort group at the 3 and 7 day. CONCLUSIONS: Corticotomy accelerates OTM in rats and it may result from promoted bone resorption via increased RANKL expression in periodontal tissue.

[Outcome of one-visit and multiple-visit root canal treatment for cracked tooth with pulpitis: a meta analysis].

PURPOSE: To compare the treatment effect between one-visit and multiple-visit endodontic treatment for cracked tooth with pulpitis. METHODS: The literatures published before 2016-06-01 regarding to one-visit and multiple-visit root canal treatment for cracked tooth with pulpitis were searched through MEDLINE, CNKI, VIP, Wanfang Database et al. Then the included studies were chosen according to the inclusion criteria. Collection of features, quality evaluation and analysis of treatment effect, follow-up results (half year/1 year) and postoperative pain of the included studies were analyzed using Stata/SE12.1 software. RESULTS: A total of 24 Chinese literatures were included and no eligible foreign literatures were found. There were 3065 cases including 1608 with one-visit endodontic treatment and 1457 with multiple-visit endodontic treatment. Meta analysis showed that the effective rate (96.90%) and follow-up success rate (94.90%,94.60%) of one-visit endodontic treatment were significantly higher than multiple-visit one (84.00%,81.40%,89.00%),while there was no significant difference in postoperative pain [RR=0.96，95%CI (0.82，1.13)].The results did not change after sensitivity analysis. However，there were some differences in assignment methods and operations details among the literatures. CONCLUSIONS: The existing limited evidences show that one-visit endodontic treatment has higher effective rate than multiple-visit endodontic treatment and its postoperative pain is acceptable. However, more standard randomized controlled trials are needed.

What do patients expect from treatment with Dental Implants? Perceptions, expectations and misconceptions: a multicenter study.

OBJECTIVE: While research in terms of patient-centered care in implant therapy is growing, few studies have investigated patients' initial perceptions prior to consultation with the implant dentist. The aim of this cross-sectional study was to capture patients' initial information level, perceptions, as well as expectations from the implant therapy. METHOD: A 34-item questionnaire was developed to investigate patients' preoperative information, perceptions and expectations from treatment with Dental Implants. The study was conducted in three locations (Hong Kong, SiChuan and JiangSu) during 2014-2015 with 277 patients. RESULTS: The main information source about implant therapy was the dentist or hygienist for less than half of the patients (n = 113, 42%). About 62.8% of participants considered that they were in general informed about implants, but only 17.7% felt confident with the information they had. More than 30% of the sample appeared to maintain dangerous misperceptions about Dental Implants: "Dental Implants require less care than natural teeth"; "Treatment with Dental Implants is appropriate for all patients with missing teeth"; "Dental Implants last longer than natural teeth"; and "Treatments with Dental Implants have no risks or complications." Patients were divided when asked whether "Dental Implants are as functional as natural teeth" (agreement frequency = 52.7%). Expectations from treatment outcome were commonly high, while there was a significant correlation between the overall mean of perception scores and outcome expectation scores (r = 0.32, P < 0.001). Overall, younger subjects (<45 years) and those with higher education level (bachelor and postgraduate) tended to present more realistic perceptions and lower outcome expectations. CONCLUSION: The majority of patients in this study presented relatively realistic perceptions. However, an alarming portion of the sample presented with inaccurate perceptions and unrealistic expectations, which the dental team would need to diagnose and correct prior to initiating implant treatment.

[Quality of life and its influential factors of children and adolescents with congenital cleft lip and palate].

PURPOSE: To investigate the quality of life of children undergoing clef lip or and palate repair as well as the influential factors of the quality of life, and provide theoretical foundation for future studies such as psychological interventions. METHODS: Totally 164 children and young adolescent patients with cleft lip and palate undergoing maxillofacial surgery and orthodontic treatment in Xuzhou Stomatology Hospital were selected as experimental group, and 102 normal children and young adolescents were selected as control group. Both groups were investigated by general information questionnaire and child and adolescents' quality of life scale (CAQOL). The results were analyzed and the influential factors on quality of life were evaluated by multivariate regression analysis with SPSS 19.0 software package. RESULTS: The overall CAQOL scores and most of the subscale scores (teacher-student relationship, peer relationships, parent-child relationship, self-awareness, physical discomfort, negative emotions, attitude about homework, access to transportation from home, extra curricular activities, self-esteem) in the experimental group were significantly lower compared with the control group (P<0.05). Single factor analysis of the quality of life showed that there was no significant difference between gender distribution; on the contrary, residential areas, parents' level of education, the main caregivers, family income and types of the disease had significant difference (P<0.05). Multiple linear regression equation showed that mother's education level of patients, cleft lip and palate category, family income, the main caregivers and residential areas were the important influential factors on children' quality of life. Among them, the type of disease was the most important influential factor (beta=0.260), followed by mother's education level (beta=0.215). CONCLUSIONS: The quality of life of children with cleft lip/palate is poor. Patients' scores of CAQOL are closely related with mothers' education level, type of cleft lip/palate, family income, the main caregivers and residential areas.

Morphological analysis of apical foramen over-instrumented by three rotary NiTi systems.

OBJECTIVE: To evaluate morphological changes of the apical surface after root canal preparation with 1 mm beyond the apical foramen using ProTaper Universal (PTU) files, K3 files and Twisted files (TF), respectively. METHODS: Seventy teeth with a centered apical foramen and 70 teeth with a deviated apical foramen were included as group A and group B respectively. In each group, 20 teeth were randomly assigned for root canal preparation with PTU, K3 and TF files, respectively; the remaining 10 teeth were used as the control group without any preparation. The apical foramens were examined with scanning electronic microscopy. The foramen integrity damage (FID) and dentin defects (DDs) were noted and compared between different groups. RESULTS: FID and DD were significantly less in Group A. DDs was not found in the control group. Preparation with PTU, K3, and TF files caused FID in 6.67%, 10%, and 3.33% of teeth in the group A, and in 20%, 26.67%, and 10% in Group B, respectively. Preparation with PTU, K3, and TF files caused DD in 6.67%, 6.67%, and 3.33% of teeth in Group A, and in 23.33%, 26.67%, and 6.67% in Group B, respectively. PTU and K3 files produced more DDS than TF files. However, no significant difference was found between groups using PTU and K3 files. CONCLUSION: Rotary instrumentation caused less damage on the apical surface in foramencentered root canals than foramen-deviated root canals when working beyond the canal length. TF files had a tendency to produce less DDS compared with PTU or K3 files during over-instrumented root canals.

[Coculture of stem cells from the apical papilla and human umbilical vein endothelial cells enhances the angiogenic potential of dental pulp tissues].

PURPOSE: To observe the effect of coculture of stem cells from the apical papilla (SCAPs) and human umbilical vein endothelial cells (HUVECs) on the angiogenic potential of dental pulp tissues. METHODS: SCAPs were incubated in osteo/odontogenic, adipogenic, neurogenic induction medium and α-MEM medium, whose multilineage differentiation capacities were confirmed using alizarin red staining, oil red O staining and ßIII-tubulin immunofluorescent staining. The tubular length, branching points number and junctional areas were detected after 3, 6, 9 h since cells were seeded onto matrigel, and the data was analyzed using SPSS 16.0 software package. RESULTS: SCAPs in the experimental groups were detected having more lipid droplets, mineralization nodules and neuron-like cells. Coculture of SCAPs and HUVECs formed more vessel-like structures in tubular formation assay. CONCLUSIONS: SCAPs are capable of differentiating into fat, bone, and nerve-like cells in vitro. Coculture of SCAPs and HUVECs can enhance the angiogenic potential of dental pulp tissues.

[Comparative analysis of the relationship between of chronic periodontitis patients' compliance and clinical efficacy].

OBJECTIVE: To evaluate the effect of patients' compliance on clinical parameters in patients with chronic periodontitis during periodontal maintenance therapy period. METHODS: Chronic periodontitis patients who had completed non-surgical periodontal basic treatment were incorporated into the periodontal maintenance therapy(PMT). Clinical examination was performed in the baseline and each quarterly recall, over 3-year period. Clinical parameters including number of teeth, probing depth(PD), attachment loss(AL) level and bleeding on probing(BOP), were recorded. According to the number of PMT visit, the patients were classified into three groups:regular complier(RC); erratic complier(EC); non-complier(NC). The final parameters(three years later) were obtained by outpatient follow-up and telephone interviews. The data were calculated for the pecentage of sites with PD 4-5 mm, PD ≥ 6 mm, AL 4-5 mm, AL ≥ 6 mm, BOP, and the number of tooth loss per patient and the rates of progression of periodontitis.Statistical analyses including ANOVA test and Chi-square test were performed by SPSS 16.0 software package. RESULTS: The percentage of clinical parameters in RC [AL 4-5 mm :(14.8 ± 5.0)%, AL ≥ 6 mm: (9.3 ± 3.1)%, BOP: (22.8 ± 4.2)%] were significantly decreased compared with that at baseline [AL 4-5 mm:(19.0 ± 6.0)%, AL ≥ 6 mm: (10.6 ± 3.1)%, BOP:(30.3 ± 5.6)%] (P < 0.01). There was significant difference between RC and NC [AL 4-5mm:(43.3 ± 1.3)%, AL ≥ 6 mm:(31.3 ± 1.7)%, BOP (91.5 ± 5.4)%] (P < 0.01), and between RC and EC[AL 4-5 mm: (18.9 ± 6.7)%, AL ≥ 6 mm: (12.6 ± 5.4)%, BOP:(38.4 ± 5.2)%] (P < 0.05). The progression rate of periodontitis [19.1% (4/21) at subject level, 0.7% (434/61 362) at site level] and tooth loss (1.0) was significantly lower in RC compared with EC and NC patients. CONCLUSIONS: Regular periodontal maintenance enables the patients with chronic periodontitis to maintain long-term efficacy.

[The influential factors of patients' compliance with supportive periodontal therapy].

PURPOSE: To discuss the influential factors of patients' compliance with chronic periodontitis during supportive periodontal therapy (SPT) period and the counter measures. METHODS: Chronic periodontal patients completing intial non-surgical therapy with SPT were investigated with a self-designed questionnaire after 2 years by outpatient follow-up and telephone interviews to obtain information for analysis. RESULTS: One hundred and one effective scales were collected. Factors influenced patients' compliance including disease awareness, health care quality, age, education level, economic status and so on. CONCLUSIONS: There are many factors influencing patients' compliance, and the key to improve patient compliance is that doctors should instruct the patients appropriately, follow up annually, and improve the quality of medical services.

[The application of problem-based learning and case-based study in the practice teaching of clinical prosthodontics courses].

PURPOSE: To study the effect of problem-based learning(PBL) and case-based study(CBS) for knowledge acquisition and clinical performance in the practice teaching of clinical prosthodontics courses. METHODS: Consecutive cohorts of year 2 clinical students taught using a traditional prosthodontics curriculum (students who practiced in Xuzhou Stomatological Hospital from June 2007 to June 2008, n=30) and a PBL and CBS curriculum (who practiced in Xuzhou Stomatology hospital from June 2008 to June 2009, n=30) were compared.Students completed an end-of-attachment examination and a questionnaire in which students were requested to rate themselves on 7 competencies. The data was analyzed with CS10.34 software package. RESULTS: The PBL and CBS curriculum resulted in significantly better examination performance than did the traditional teaching curriculum (P<0.05). The excellent rate was 46.7% in the PBL and CBS curriculum while 23.3% in the traditional teaching curriculum. It was found that most students considered PBL and CBS useful for them. CONCLUSIONS: Examination performance indicates that the PBL and CBS curriculum is more successful than the previous course. PBL and CBS can be used to stimulate and underpin the acquisition of knowledge, skill and attitudes, and is worthy of generalization in clinical prosthodontics courses.

[Foreign stone retaining in right post-maxillary molar area for 10 years causing limitation of mouth opening: report of one case].

It is common to see a foreign body retained in the soft tissues of oral and maxillofacial region. However, a foreign body retaining in oral and maxillofacial region for more than 10 years and resulting in limitation of mouth opening is rare. This paper reported a 52-year-old man, who had limitation of mouth opening for more than 1 year caused by a stone retaining in right post-maxillary molar area for 10 years. The clinical manifestations, X-ray and CT findings, treatment result were summarized. This case suggested that oral and maxillofacial surgeons should ask the patients medical history in details. With other imaging examinations, surgeons could make definite diagnosis of oral and maxillofacial foreign body.

[Clinical study of cancellous iliac bone graft in cleft alveolar repair].

PURPOSE: To analyze the factors affecting the effect of cleft alveolar repair. METHODS: 21 patients with alveolar cleft who were treated in our hospital between 2003-2007 were included in this study. The factors that affected the cleft alveolar repair such as patient's age, cleft type, surgical method, source of bone were analyzed accordingly. RESULTS: (1) The surgical success rate was 95.24%, the clinical success rate was 90.48%; (2) The effect of bone graft correlated with the patient's age;(3) Surgical success rate of unilateral alveolar cleft was higher than that of bilateral alveolar cleft. CONCLUSIONS: (1) The younger patients, the greater chance of success in bone graft. Patients aged 9-11 years are appropriate candidates for the surgery , when the canine is erupting; (2) Iliac bone is a good source for bone graft; (3)Good bone bed and tight tension-free suture are the key to surgical success.

[Treatment of primary trigeminal neuralgia with radiofrequency thermogangliocoagulation: Report of 152 consecutive cases].

PURPOSE: To evaluate the clinical results of primary trigeminal neuralgia treated by RFT and investigate the methods to manage complications. METHODS: 152 cases of primary trigeminal neuralgia were collected from 2001 to 2004, a retrospective study was undertaken to analyze the clinical characters such as effective rate, ineffective rate and the rate of complications of patients treated with RFT. RESULTS: The average age of the 152 cases was 48.9 years old, the rate of male to female was 1:1.3. The effective rate of primary trigeminal neuralgia treated with RFT was 94.1%, the ineffective rate was 2.6%;another 3.3% cases gave up or altered to other methods, the rate of complications was 15.8%. CONCLUSIONS: RFT is an effective method to treat primary trigeminal neuralgia with few severe complications and low mortality rate, which can save the sense of touch partly. Recurrent cases can be retreated with RFT.

[Clinical observation of the height of the alveolar after bone grafting in cleft alveolar repair in various ages.].

PURPOSE: To evaluate the changes of transplanted bones after cancellous iliac bone grafting in cleft alveolar repair in various ages. METHODS: The patients were divided into A and B groups according to their canine eruption. The changes of alveolar height in grafting regions were examined by clinical follow up and radiographs after the cancellous iliac bone grafting in cleft alveolar repair. RESULTS: The bone grafting before the eruption of canines was more effective than that after eruption. The orthodontics after operation can increase the alveolar height. CONCLUSION: The alveolar height after the bone grafting in cleft alveolar repair increased with the eruption of canines.