Sodium fluoride-induced autophagy of ameloblast-like cells via the p-ULk1/ATG13/LC3B pathway in vitro.

OBJECTIVE: To investigate the effects of sodium fluoride on the ameloblast and reveal the mechanism of dental fluorosis. MATERIALS AND METHODS: Mouse ameloblast-like cell line (ALC) cells were treated with various concentrations of NaF, and subjected to Incucyte, fluorescence immunoassay, transmission electron microscopy, reverse transcription quantitative polymerase chain reaction (RT-qPCR), western blot for autophagy examination, alkaline phosphatase and alizarin red staining for mineralization after osteogenic induction. RESULTS: NaF exerts a dose-dependent inhibitory effect on ALC cell growth. TEM and fluorescence immunoassay showed that 1.5 mM or higher concentrations of NaF could induce a fusion of lysosome and mitochondria, finally increasing the number of autophagosome. RT-qPCR and western blot showed that the upregulation of autophagy related gene 13 (ATG13), downregulation of phosphorylated Unc-51-like kinase 1 (p-ULK1) were found in NaF-induced autophagy of ALC cells. The knockdown of ATG13 could rescue it as well as the expression of p-ULK1 and LC3B. Besides, alizarin red staining showed that fluoride under these concentrations could promote the mineralization of ALC. CONCLUSIONS: The data show that fluoride in higher concentration can induce autophagy via the p-ULk1/ATG13/LC3B pathway of ALCs than lower ones promote mineralization in vitro, which provides insight into the function of NaF in the autophagy and mineralization of ameloblast.

[A clinical application study of digital manufacturing simple intraoral Gothic arch-tracing device in determining the centric relation of complete dentures].

OBJECTIVE: To verify the consistency between the digital manufacturing simple intraoral Gothic arch-tracing device and the traditional intraoral Gothic arch-tracing device in determining the centric relation of complete dentures restoration. METHODS: Ten outpatients with edentulous jaws were selec-ted, and the centric relation of the patients was determined by digital manufacturing of simple intraoral Gothic arch-tracing device (T1) and traditional intraoral Gothic arch-tracing device (T2); the difference of clinical operation time between the two methods was recorded; the upper and lower edentulous jaw plaster models were scanned with two kinds of centric relation, the Standard Triangle Language (STL) files imported into Geomagic studio software to apply the best fitting of multiple points of the both upper jaw models, the fitted STL files imported into the 3 shape viewer software, and the maximum position deviations of the vertical, labial (buccal) and lingual directions of the mandibular midline area and molar areas in T1 and T2 groups measured. During the clinical complete dentures try-in, we observed whether there was midline deviation in the mouth of T1 group and T2 group, and whether the occlusion of posterior teeth was stable or not. RESULTS: The mean time spent on determining the centric relation of T1 and T2 groups was (41.90±2.64) min, (57.50±2.37) min respectively. Paired t test was conducted in the two groups, P < 0.01 with significant statistical difference; The mean maximum position deviation between T1 group and T2 group of the midline mandibular region in labial lingual direction was (0.32±0.14) mm, that was (0.40±0.23) mm in vertical direction; the mean maximum position deviation of molar area in buccal lingual direction was (0.35±0.23) mm and that was (0.33±0.20) mm in vertical direction. In the vertical and horizontal directions, the maximum position deviation of mandibles between group T1 and group T2 was controlled within 0.5 mm. In the process of clinical complete dentures try-in, there was no deviation from the center line of dentures. There was not warping, swinging and other poor stability phenomena in T1 and T2 groups. CONCLUSION: The digital manufacturing of simple intraoral Gothic arch-tracing device can be used to determine the centric relation of complete dentures, which can not only save time of clinical operation, but also ensure the accuracy of the centric relation.

Determination of gastrointestinal tract colonization sites from feedlot cattle transiently shedding or super-shedding Escherichia coli O157:H7 at harvest.

AIMS: The objective of the study was to determine levels of Escherichia coli O157:H7 colonization in the gastrointestinal tract (GIT) of naturally shedding cattle shedding the pathogen at low- or super-shedder levels. METHODS AND RESULTS: Over 2 years, feedlot cattle were sampled multiple times for faecal shedding of E. coli O157:H7. Just prior to harvest (1-2 days), animals that were super-shedders (≥104  CFU per gram of faeces) were specifically identified, and based on the longer term screening data, pen cohorts that were low-shedders (years 1 and 2) or chronic-shedders (year 1) were also identified. At harvest, samples were collected from throughout the GIT, including the rectoanal junction (RAJ) for enumeration and enrichment of E. coli O157:H7. The mouth samples exhibited the greatest prevalence for the pathogen, and the abomasum and rumen exhibited the lowest prevalence (P < 0·05). Super-shedders had significantly greater prevalence for all GIT locations except the mouth and abomasum compared to low-shedders, but the super-shedders were the only animals with positive abomasum samples. Samples from the super-shedders were enumerable for most GIT locations, and the rectum and RAJ locations were the only locations that were significantly greater than other locations (P < 0·05). CONCLUSIONS: Across all animals naturally exposed to E. coli O157:H7, the risk of ingestion is high, but rumen and abomasum are potential barriers to passage. In super-shedders, the passage through the GIT was greater, allowing colonization in the rectum and at the RAJ. SIGNIFICANCE AND IMPACT OF THE STUDY: Escherichia coli O157:H7 low-shedding cattle had lower pathogen levels throughout the GIT, indicating intrinsic GIT factors to these cattle may reduce pathogen passage through the GIT, including the abomasum, and minimize risk of RAJ colonization.

[Analysis of edge morphology of partial veneers made by different processing techniques and materials].

OBJECTIVE: To compare the edge morphology of partial veneers made of different materials by slurry molding, heat-pressed and computer aided design/computer aided manufacturing (CAD/CAM) techniques. METHODS: Thirty premolars with smooth surface and intact enamel were selected and randomly divided into five groups, 6 specimens for each group. Group A were made from feldspathic porcelain (Noritake®) by slurry molding, while Group B were made from lithium disilicate glass ceramic (IPS E.max® Press) by heat-pressed. Group C/D/E were respectively made from feldspar porcelain block (VITA Mark II®), zirconia-reinforced glass ceramic (VITA Suprinity®) and hybrid ceramic with a ceramic-polymer network (VITA Enamic®) by CAD/CAM techniques. All the partial veneers luted with light-cured composite resin. Then the partial veneers were trimmed and polished to achieve the smooth finishing margin, clinical polishing sets were used according to the product descriptions. Scanning electron microscope (SEM) was used to observe the edge morphology of prostheses and the exposure of resin cements. RESULTS: The smooth surface and knife-like edge of the partial veneers could be obtained after bonding, trimming and polishing. The edges of Group A were slightly rough and the width of the exposed adhesive was (106.00±9.17) µm. In Group B, the edges were smoother than Group A, and the exposed wide adhesive strip was visible, which was (138.33±20.59) µm. In Group E, the edges were smooth too, and the width of exposed adhesive strip was (186.00±5.66) µm. The edges of Group C and Group D were rough and uneven, and the adhesive was rarely exposed, they were (50.67±7.51) µm and (65.67±17.90) µm. There were all significant differences between two groups, except Group C and Group D. CONCLUSION: After trimming and polishing in accordance with clinical procedures, the expected knife-like edge can be obtained in all groups. The width of the exposed resin adhesive of each group is different, the order: Mark II/Suprinity < Noritake < E.max Press < Enamic. The edge morphology of partial veneers in different processing technic and materials are different.

MicroRNA-135b inhibits odontoblast-like differentiation of human dental pulp cells by regulating Smad5 and Smad4.

AIM: To investigate the function of miRNAs in odontoblast-like differentiation of human dental pulp cells (hDPCs). METHODOLOGY: Integrated comparative miRNA microarray profiling was used to determine the differential miRNAs expression in odontoblast-like differentiation of hDPCs. The abundance of microRNA-135b (miR-135b) was measured by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). Bioinformatic analyses combined with luciferase assays were utilized to identify the targets interacting with miR-135b. Overexpression of miR-135b was performed to investigate the role and mechanism in odontoblast-like differentiation of hDPCs. Statistical analysis was performed by one-way analysis of variance (anova) or Student's t-test. RESULTS: Thirty-six differentially expressed microRNAs in odontoblast-like differentiation of hDPCs were identified. MiR-135b expression was significantly downregulated during hDPCs differentiation (P < 0.05). In addition, miR-135b was able to bind to the 3'-UTR of the Smad5 and Smad4 and repressed these two genes expression (P < 0.05). Furthermore, overexpression of miR-135b suppressed odontoblast-like differentiation of hDPCs and attenuated the expression of Smad5 and Smad4 (P < 0.05). CONCLUSIONS: These observations indicated a potential role of miR-135b in mediating odontoblast-like differentiation of hDPCs and inhibition of miR-135b might be a promising therapeutic way to facilitate dentine tissue engineering.

Expression of the stem cell factor in fibroblasts, endothelial cells, and macrophages in periapical tissues in human chronic periapical diseases.

Stem cell factor (SCF), an important stem cell cytokine, has multiple functions. Fibroblasts (FBs), mature mast cells, endothelial cells (ECs), and eosinophil granulocytes can produce SCF in the inflammatory process. Therefore, we aimed to observe SCF expression in FBs, ECs, and macrophages (MPs) in periapical tissues in human chronic periapical disease and investigate the effects of cells expressing SCF in pathogenesis of the disease. Healthy (N = 20), periapical cyst (N = 15), and periapical granuloma (N = 15) tissues were fixed in 10% formalin for 48 h, embedded in paraffin, and stained with hematoxylin and eosin to observe histological changes. SCF expression was observed in FBs, ECs, and MPs in periapical tissues by double immunofluorescence. CD334, CD31, and CD14 are specific markers of FBs, ECs, and MPs, respectively. Results showed that densities of CD334-SCF double-positive FBs, CD31-SCF double-positive ECs, and CD14-SCF double-positive MPs were significantly increased in periapical tissue groups (P < 0.01). There were no significant differences in CD334-SCF double-positive FB and CD31-SCF double-positive EC levels between the two periapical tissue groups (P > 0.05). CD14-SCF double-positive MP density was considerably higher in periapical granulomas than in cysts (P < 0.01). FB, EC, and MP levels were significantly high and densities of CD334-SCF double-positive FBs, CD31-SCF double-positive ECs, and CD14-SCF double-positive MPs improved considerably in chronic periapical tissues, suggesting that the cells might be related to occurrence, development, and pathogenesis of chronic periapical disease.

[Efficacy and safety of pegylated interferon α-2b injection (Y shape, 40 kD) in treatment of patients with genotype 1/6 chronic hepatitis C].

Objective: To investigate the efficacy and safety of the new investigational drug pegylated interferon α-2b (Peg-IFN-α-2b) (Y shape, 40 kD) injection (180 µg/week) combined with ribavirin in the treatment of patients with genotype 1/6 chronic hepatitis C (CHC), with standard-dose Peg-IFN-α-2a combined with ribavirin as a positive control. Methods: A multicenter, randomized, open-label, and positive-controlled phase III clinical trial was performed. Eligible patients with genotype 1/6 CHC were screened out and randomly divided into Peg-IFN-α-2b(Y shape, 40kD) group and Peg-IFN-α-2a group at a ratio of 2:1. The patients in both groups were given oral ribavirin for 48 weeks in addition and then followed up for 24 weeks after drug withdrawal. Abbott Real Time HCV Genotype II was used to determine HCV genotype, and Cobas TaqMan quantitative real-time PCR was used to measure HCV RNA level at 0, 4, 12, 24, 48, and 72 weeks. Adverse events were recorded in detail. The primary efficacy endpoint was sustained virological response (SVR), and a non-inferiority test was also performed. Results: A total of 561 patients with genotype 1/6 CHC were enrolled, among whom 529 received treatment; 90.9% of these patients had genotype 1 CHC. The data of the full analysis set showed that SVR rate was 69.80% (95% CI 65.00%-74.60%) in the trial group and 74.16% (95% CI 67.73%-80.59%) in the control group (P = 0.297 0). The data of the per protocol set (PPS) showed that SVR rate was 80.63% (95% CI 76.04%-85.23%) in the trial group and 81.33% (95% CI 75.10%-87.57%) in the control group (P = 0.849 8), and the 95% CI of rate difference conformed to the non-inferiority standard. The analysis of the PPS population showed that of all subjects, 47.9% achieved rapid virologic response, with a positive predictive value of 93.8%. The incidence rate of adverse events was 96.30% in the trial group and 94.94% in the control group, and the incidence rate of serious adverse events was 5.13% in the trail group and 5.06% in the control group. Conclusion: In the regimen of Peg-IFN-α combined with ribavirin for the treatment of genotype 1/6 CHC, the new investigational drug Peg-IFN-α-2b(Y shape, 40 kD) has comparable clinical effect and safety to the control drug Peg-IFN-α-2a.

Cognitive behavioral therapy eases orthodontic pain: EEG states and functional connectivity analysis.

OBJECTIVES: To assess the effects of CBT on electroencephalogram activity in patients with orthodontic pain. METHODS: We recruited 24 young (18-28 years), healthy individuals with matched baseline characteristics, including pain intensity, anxiety levels, personality traits, and life-quality scores. Participants were randomly assigned to either the CBT intervention group (n = 12) or the blank control group (n = 12). Multichannel continuous electroencephalogram signals and visual analog scale (VAS) scores were recorded before and after initial archwire placement for 1 week. A 1-month follow-up was conducted, when participants' daily VAS scores were recorded. RESULTS: The overall EEG spectral power of the CBT group was lower than that of the control group, especially in the theta (4-7 Hz) and beta (14-30 Hz) bands during the treatment period. An enhanced coupling of theta and beta frequencies was observed in frontal and occipital electrodes, respectively. The EEG power in delta and theta bands correlated positively with pain intensity. Network coherence for the CBT group exhibited higher connectivity in the theta band. CONCLUSIONS: Specific cerebral responses to CBT instructions could be detected with continuous electroencephalograms and related to orthodontic pain processing, which may provide a new insight in exploring CBT for orthodontic pain control.

Novel polymorphic microsatellite markers in Odontobutis potamophila.

We characterized 16 novel polymorphic loci isolated from a partial genomic DNA library of Odontobutis potamophila enriched for CA repeats. We tested the variability of these microsatellites on 51 unrelated individuals collected in China. All loci were polymorphic. The average allele number was 14.6 per locus, ranging from 2 to 27. The observed heterozygosity ranged from 0.35 to 0.90, with an average of 0.70, whereas the average expected heterozygosity was 0.76. Twelve of the 16 microsatellites conformed to Hardy-Weinberg equilibrium and were inherited independently. These developed microsatellites will be useful in studies of population genetics and other genetic studies on this important food species.

Peri-implant conditions and their relationship with periodontal conditions in Chinese patients: a cross-sectional study.

OBJECTIVES: To analyze the relationships between peri-implant conditions and periodontal conditions in Chinese patients with dental implants in place for at least 1 year. MATERIAL AND METHODS: Seventy-six patients (mean age, 41 ± 10 years; range, 21-69 years) who received placement of 120 dental implants (Straumann(®) ), (mean 1.6 implants per subject; range, 1-5 implants per subject) after a mean period of 25 months (range, 12-66 months) responded to recall. Clinical examinations were performed around the implants and natural teeth. Periapical radiographs were taken by the long cone technique for implants, and radiographic bone level (BL) was measured. Comparisons of the peri-implant conditions were performed between the patients with different periodontal conditions by t-test and chi-square test. The relative risk of periodontal condition as a risk factor for peri-implant conditions was analyzed by logistic regression. RESULTS: Subjects who presented with ≥5% sites with probing depth (PD) ≥ 4 mm and ≥30% sites with bleeding on probing (BoP) in the dentition showed significantly poorer peri-implant conditions (58% vs. 18% subjects who had maximum modified gingival index (mGI) 2 or 3, P = 0.003; 94% vs. 62% subjects who had maximum PD ≥ 4 mm, P = 0.008; 100% vs. 79% subjects who had BoP, P = 0.044; mean PD 3.36 ± 0.66 vs. 2.75 ± 0.66 mm, P = 0.002; and sites% with BoP 68 ± 23% vs. 36 ± 31%, P < 0.001), as compared with those who had <5% sites with PD ≥ 4 mm and <30% sites with BoP on the remaining teeth. The relative risk for subjects with the more severe and extensive periodontal conditions compared to those with better periodontal conditions to have PD ≥ 5 mm with BoP at peri-implant sites was 23.3 (P = 0.003, 95% CI, 2.8-192.3. CONCLUSIONS: The peri-implant conditions were significantly related to the periodontal conditions around the remaining natural teeth, which implies that control of periodontal disease is essential for successful implant treatment.

Efficacy of a pegaspargase-based regimen in the treatment of newly-diagnosed extranodal natural killer/T-cell lymphoma.

Extranodal natural killer (NK)/T-cell lymphoma (ENKL) is an aggressive neoplasm with poor prognosis. Currently, there is no consensus on the optimal treatment of this disease. In this study, we report the efficacy of a pegaspargase (PEG-Asp)-based chemotherapy, a DDGP regimen (PEG-Asp, dexamethasone, cisplatin, gemcitabine), for the treatment of newly-diagnosed ENKL. From August 2010 to May 2012, 12 patients with newly-diagnosed stage II - IV ENKL were initially treated with a DDGP regimen in our center. Ten patients (10/12, 83.3%) achieved complete response (CR) and two (2/12, 16.7%) achieved partial response (PR). The objective overall response rate (ORR) was 100%. Three patients (3/12, 25.0%) relapsed, and as a result, two died of disease. Eight patients (8/12, 66.7%) were alive with no evidence of disease (NOD) after a median follow-up of 19 months (range 16 - 31 months). Hematologic toxicity was the most frequent toxicity reported in this study. Grade 3/4 leukopenia and neutropenia were common and both occurred in eight patients (8/12, 66.7%), respectively. Additionally, six patients (6/12, 50.0%) experienced grade 3/4 thrombocytopenia and three (3/12, 25.0%) experienced grade 3/4 anemia. However, no patient died of hematologic toxicity. Our results demonstrate the significant efficacy and safety profile of a DDGP regimen in the treatment of newly-diagnosed ENKL, and indicate the potential of this regimen as a first-line therapy against this disease.

Fatigue and nanomechanical properties of K3XF nickel-titanium instruments.

AIM: To examine the fatigue behaviour of heat-treated NiTi instruments when immersed in aqueous media and to determine the effect of cyclic fatigue on the hardness and elastic modulus of NiTi instruments using a nanoindentation technique. METHODOLOGY: K3XF and K3 NiTi instruments, both in sizes 25, 0.04 taper and 40, 0.04 taper, were subjected to rotational bending at a curvature of 42° either in air or under deionized water, and the number of revolutions to fracture (Nf ) was recorded. The fracture surface of all fragments was examined with a scanning electron microscope. The hardness and elastic modulus of the fracture surface of instruments sized 25, 0.04 taper were then measured using a nanoindentation test. RESULTS: The K3XF instruments had a fatigue resistance superior to K3 instruments under dry and aqueous environments (P < 0.05). The fatigue life of K3 instruments was similar under both conditions, whereas the Nf of K3XF was greater under water than in air, especially at the size 40, 0.04 taper (P < 0.05). The values for the fraction of the area occupied by the dimple region were significantly smaller in K3XF instruments than in K3 instruments, especially under water (P < 0.05). There was no difference in hardness on K3XF instruments between new files and instruments subjected to the fatigue process. The hardness of instruments subjected to the fatigue process was significantly lower in K3XF than in K3 instruments (P < 0.05). CONCLUSION: The fatigue life of K3XF instruments under water is longer than it is for K3XF instruments in air. There was no work-hardening effect on K3XF instruments subjected to the fatigue process.

[Histone demethylase JMJD3 inhibits alveolar bone loss by regulating macrophage polarization in periodontitis].

Objective: To investigate the expression of histone demethylase, Jumonji domain-containing protein 3 (JMJD3), in inflammatory periodontal tissues and its potential mechanism for the regulation of periodontitis. Methods: The results of single-cell sequencing of periodontal tissues published in the Gene Expression Omnibus (GEO) database in 2022 were analyzed. Nine gingival samples each from healthy and inflamed periodontal patients were collected during periodontal surgery or tooth extractions for immunohistochemical staining and real-time fluorescence quantitative PCR (RT-qPCR). Mice periodontitis models were constructed, and the experimental groups were: healthy control+saline group, silk ligation+saline group, silk ligation+GSK-J4(inhibitor of JMJD3) group. Lipopolysaccharide (LPS) derived from Porphyromonas gingivalis (Pg) (Pg-LPS) was used to mimic the periodontal inflammatory microenvironment. The macrophages were treated with small interfering RNA (siRNA) targeting Jmjd3 and the JMJD3 inhibitor GSK-J4. siRNA transfection experiments were grouped into the following: the NC group (negative control sequence transfection group), the siRNA-Jmjd3 group, the NC+LPS group, siRNA-Jmjd3+LPS group. Inhibitor experiments were grouped as dimethyl sulfoxide (DMSO) group, GSK-J4 group, DMSO+LPS group, GSK-J4+LPS group. Western blotting and immunofluorescence staining were used to explore the effects of JMJD3 on macrophage polarization and periodontal inflammation in the in vivo and in vitro settings. Results: RT-qPCR results showed that JMJD3 expression in gingival tissues of periodontitis patients (1.97±0.91) was significantly higher than that in healthy gingival tissues (1.00±0.33) (t=2.45, P=0.048). RT-qPCR results of in vitro experiments showed that either siRNA knockdown of JMJD3 or inhibition of JMJD3 using GSK-J4 promoted M1 polarization and inhibited M2 polarization in macrophages under inflammatory environment: the expression of arginase I (Arg 1) in the NC+LPS group (0.90±0.06) was significantly higher than that in the siRNA-Jmjd3+LPS group (0.61±0.11) (P<0.01); the expression of interleukin (Il)-6, Il-1ß, and tumor necrosis factor alpha (Tnf-α) in the NC+LPS group (8.50±0.16, 5.56±0.20, 3.44±0.16) were significantly lower than those in the siRNA-Jmjd3+LPS group (14.63±0.48, 8.55±0.10, 11.72±0.16) (P<0.01). The expression of Arg-1, Ym1, Il-10 in the DMSO+LPS group (0.82±0.01, 0.35±0.16, 1.47±0.11) were significantly higher (P<0.01) than the GSK-J4+LPS group (0.55±0.03, 0.22±0.21, 0.51±0.11); the expression of Il-6, Il-1ß, and Tnf-α in the DMSO+LPS group (2.03±0.13, 3.63±0.14, 4.06±0.03) were significantly lower than the GSK-J4+LPS group (2.69±0.16, 15.04±1.15, 4.36±0.10) (P<0.01). The results of the in vivo experiments revealed that inhibition of JMJD3 exacerbated bone loss in experimental periodontitis mice, increased macrophage M1 polarization, and decreased M2 polarization in inflamed periodontal tissues. The buccal cemento-enamel junction (CEJ)-alveolar bone crest (ABC), palatal CEJ-ABC, as well as the ratio of M1/M2 type macrophages were significantly lower in the silk ligation+saline group [(0.26±0.03), (0.24±0.01) mm, 0.35±0.10) than in the silk ligation+GSK-J4 group [(0.34±0.04), (0.30±0.05) mm, 2.50±0.58) (t=3.65, P=0.006; t=2.67, P=0.049; t=7.31, P=0.004; respectively). Conclusions: Single-cell sequencing as well as the in vitro and in vivo experiments verified that JMJD3 expression was upregulated in periodontitis periodontal tissues. JMJD3 may exert a protective role in periodontitis by regulating macrophage polarization, thereby inhibiting alveolar bone destruction associated with the periodontitis.

The Role of Pericyte Migration and Osteogenesis in Periodontitis.

A ligature-induced periodontitis model was established in wild-type and CD146CreERT2; RosatdTomato mice to explore the function of pericytes in alveolar bone formation. We found that during periodontitis progression and periodontal wound healing, CD146+/NG2+ pericytes were enriched in the periodontal tissue areas, which could migrate to the alveolar bone surface and colocalize with ALP+/OCN+ osteoblasts. Chemokine C-X-C motif receptor 4 (CXCR4) inhibition using AMD3100 blocked CD146-Cre+ pericyte migration and osteogenesis, as well as further exacerbated periodontitis-associated bone loss. Next, primary pericytes were sorted out by magnetic-activated cell sorting and demonstrated that C-X-C motif chemokine ligand 12 (CXCL12) promotes pericyte migration and osteogenesis via CXCL12-CXCR4-Rac1 signaling. Finally, the local administration of an adeno-associated virus for Rac1 overexpression in NG2+ pericytes promotes osteoblast differentiation of pericytes and increases alveolar bone volume in periodontitis. Thus, our results provided the evidence that pericytes may migrate and osteogenesis via the CXCL12-CXCR4-Rac1 axis during the pathological process of periodontitis.

Effective reinforcement of electrical conductivity and strength of carbon nanotube fibers by silver-paste-liquid infiltration processing.

A carbon-nanotube (CNT)/silver/polymer composite fiber was fabricated using carbon nanotube fiber (CNTF) to infiltrate silver-paste liquid for effective reinforcement of electrical conductivity and strength of the CNT fibers. The as-obtained composite fiber is still flexible with a content of 43 wt% CNTs. Scanning electronic microscopy (SEM) observation shows that the silver-paste layer covering on the surface of the CNTF and polymer infiltrated into the CNTFs. The electrical conductivity and strength of the achieved composite fiber were effectively improved. Mechanical measurement of the composite fiber gave a strength of 940 MPa, 2.7 times that of a reference CNTF. The electrical conductivity of the composite fiber is 5.0 × 10(5) S m(-1), 2.6 times that of the referenced CNTF. Additionally, through control of the fabrication process, a coaxial fiber comprising a silver-paste "tube" and pure CNT fiber can be achieved. This route for making composite fibers is easy and controllable, apt for development of high-performance fibers.

Apically extruded debris and irrigant with two Ni-Ti systems and hand files when removing root fillings: a laboratory study.

AIM: To compare the amount of apically extruded debris and irrigant produced by two Ni-Ti instruments and hand files when removing root fillings, and to compare two experimental models. METHODOLOGY: Sixty single straight root canals in human mandibular premolars were prepared with K-files and filled with gutta-percha and AH Plus sealer. The teeth were randomly divided into three groups of 20 for removal of the root filling material with Reciproc files (Group 1, RP), Mtwo retreatment files (Group 2, MR) or hand files (Group 3, H). Each group was then equally divided into experimental subgroups: A, with 1.5% agar gel model (AG); B, with empty tube model (ET). Apically extruded debris and irrigant was quantified by subtracting the initial weight of the test apparatus without a tooth from its weight after the root canal retreatment. Comparative analysis of the amount of apically extruded debris and irrigant for each of the instruments and the experimental models was performed. Time for gutta-percha removal was recorded. Data were statistically analysed using one-way analysis of variance. RESULTS: Removal of root fillings with two Ni-Ti instruments produced less apically extruded debris and irrigant than hand files in both experimental models (P < 0.05). More apically extruded debris and irrigant was produced with Reciproc files than Mtwo retreatment files using the 1.5% agar gel model (P > 0.05). Significantly more apically extruded debris and irrigant was produced with Reciproc files than Mtwo retreatment files using the empty tube model (P < 0.05). The time required to remove the root fillings followed Reciproc

Machine Learning Analysis of Microtensile Bond Strength of Dental Adhesives.

Dental adhesives provide retention to composite fillings in dental restorations. Microtensile bond strength (µTBS) test is the most used laboratory test to evaluate bonding performance of dental adhesives. The traditional approach for developing dental adhesives involves repetitive laboratory measurements, which consumes enormous time and resources. Machine learning (ML) is a promising tool for accelerating this process. This study aimed to develop ML models to predict the µTBS of dental adhesives using their chemical features and to identify important contributing factors for µTBS. Specifically, the chemical composition and µTBS information of 81 dental adhesives were collected from the manufacturers and the literature. The average µTBS value of each adhesive was labeled as either 0 (if <36 MPa) or 1 (if ≥36 MPa) to denote the low and high µTBS classes. The initial 9-feature data set comprised pH, HEMA, BisGMA, UDMA, MDP, PENTA, filler, fluoride, and organic solvent (OS) as input features. Nine ML algorithms, including logistic regression, k-nearest neighbor, support vector machine, decision trees and tree-based ensembles, and multilayer perceptron, were implemented for model development. Feature importance analysis identified MDP, pH, OS, and HEMA as the top 4 contributing features, which were used to construct a 4-feature data set. Grid search with stratified 10-fold cross-validation (CV) was employed for hyperparameter tunning and model performance evaluation using 2 metrics, the area under the receiver operating characteristic curve (AUC) and accuracy. The 4-feature data set generated slightly better performance than the 9-feature data set, with the highest AUC score of 0.90 and accuracy of 0.81 based on stratified CV. In conclusion, ML is an effective tool for predicting dental adhesives with low and high µTBS values and for identifying important chemical features contributing to the µTBS. The ML-based data-driven approach has great potential to accelerate the discovery of new dental adhesives and other dental materials.

p38a MAPK is involved in BMP-2-induced odontoblastic differentiation of human dental pulp cells.

AIM: To investigate whether the p38α mitogen-activated protein kinases (MAPK) is involved in bone morphogenetic protein (BMP)-2-induced odontoblastic differentiation of human dental pulp cells (HDPCs). METHODOLOGY: Recombinant retrovirus encoding shRNA against p38α MAPK was constructed to investigate the role of p38α MAPK on BMP-2-induced odontoblastic differentiation of HDPCs. HDPCs were transfected with retrovirus expressing sh-p38α. Activation of p38α MAPK was detected by Western blot. The effects of p38α MAPK on BMP-2-induced odontoblastic differentiation of HDPCs were measured by alkaline phosphatase (ALP) activity, and the expression of odontoblastic markers was identified by quantitative real-time polymerase chain reaction analysis. The effect of SD-282, a p38a-specific inhibitor, on BMP-2-induced odontoblastic differentiation was also investigated. RESULTS: BMP-2 dose- and time-dependently upregulated phosphorylation of p38α of HDPCs. Compared with BMP-2-treatment group, gene knock-down of p38α MAPK significantly inhibited ALP activity and the formation of mineralized nodules in HDPCs. Moreover, suppression of p38α MAPK repressed the odontoblastic differentiation in HDPCs. Consistently, inhibition of p38α by SD-282 also decreased odontoblastic differentiation. CONCLUSIONS: p38α MAPK is involved in BMP-2-induced odontoblastic differentiation of HDPCs.

Poly(acrylic acid) modifying bentonite with in-situ polymerization for removing lead ions.

In this paper, a new kind of poly(acrylic acid) modified clay adsorbent, the poly(acrylic acid)/bentonite composite (PAA/HB) was prepared by in-situ polymerization, and utilized to remove lead(II) ions from solutions. The maximum adsorption of adsorbent is at pH 5 for metal ions, whereas the adsorption starts at pH 2. The effects of contact time (5-60 min), initial concentration of metal ions (200-1,000 mg/L) and adsorbent dosage (0.04-0.12 g/100 mL) have been reported in this article. The experimental data were investigated by means of kinetic and equilibrium adsorption isotherms. The kinetic data were analyzed by the pseudo-first-order and pseudo-second-order equation. The experimental data fitted the pseudo-second-order kinetic model very well. Langmuir and Freundlich isotherms were tried for the system to better understand the adsorption isotherm process. The maximal adsorption capacity of the lead(II) ions on the PAA/HB, as calculated from the Langmuir model, was 769.2 mg/g. The results in this study indicated that PAA/HB was an attractive candidate for removing lead(II) (99%).