Automatic detection of the third molar and mandibular canal on panoramic radiographs based on deep learning.

PURPOSE: This study aims to develop a deep learning framework for the automatic detection of the position relationship between the mandibular third molar (M3) and the mandibular canal (MC) on panoramic radiographs (PRs), to assist doctors in assessing and planning appropriate surgical interventions. METHODS: Datasets D1 and D2 were obtained by collecting 253 PRs from a hospitals and 197 PRs from online platforms. The RPIFormer model proposed in this study was trained and validated on D1 to create a segmentation model. The CycleGAN model was trained and validated on both D1 and D2 to develop an image enhancement model. Ultimately, the segmentation and enhancement models were integrated with an object detection model to create a fully automated framework for M3 and MC detection in PRs. Experimental evaluation included calculating Dice coefficient, IoU, Recall, and Precision during the process. RESULTS: The RPIFormer model proposed in this study achieved an average Dice coefficient of 92.56 % for segmenting M3 and MC, representing a 3.06 % improvement over the previous best study. The deep learning framework developed in this research enables automatic detection of M3 and MC in PRs without manual cropping, demonstrating superior detection accuracy and generalization capability. CONCLUSION: The framework developed in this study can be applied to PRs captured in different hospitals without the need for model fine-tuning. This feature is significant for aiding doctors in accurately assessing the spatial relationship between M3 and MC, thereby determining the optimal treatment plan to ensure patients' oral health and surgical safety.

Efficacy of a mouthwash containing ε-poly-L-lysine, funme peptides and domiphen in reducing halitosis and supragingival plaque: a randomized clinical trial.

OBJECTIVE: To evaluate the antibacterial effectiveness of a combination of ε-poly-L-lysine (ε-PL), funme peptide (FP) as well as domiphen against oral pathogens, and assess the efficacy of a BOP® mouthwash supplemented with this combination in reducing halitosis and supragingival plaque in a clinical trial. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the compound against Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were determined by the gradient dilution method. Subsequently, the CCK-8 assay was used to detect the toxicity of mouthwash on human gingival fibroblastst, and the effectiveness in reducing halitosis and supragingival plaque of the mouthwash supplemented with the combination was analyzed by a randomized, double-blind, parallel-controlled clinical trial. RESULTS: The combination exhibited significant inhibitory effects on tested oral pathogens with the MIC < 1.56% (v/v) and the MBC < 3.13% (v/v), and the mouthwash containing this combination did not inhibit the viability of human gingival fibroblasts at the test concentrations. The clinical trial showed that the test group displayed notably lower volatile sulfur compounds (VSCs) at 0, 10, 24 h, and 7 d post-mouthwash (P < 0.05), compared with the baseline. After 7 days, the VSC levels of the and control groups were reduced by 50.27% and 32.12%, respectively, and notably cutting severe halitosis by 57.03% in the test group. Additionally, the Plaque Index (PLI) of the test and control group decreased by 54.55% and 8.38%, respectively, and there was a significant difference in PLI between the two groups after 7 days (P < 0.01). CONCLUSIONS: The combination of ε-PL, FP and domiphen demonstrated potent inhibitory and bactericidal effects against the tested oral pathogens, and the newly formulated mouthwash added with the combination exhibited anti-dental plaque and anti-halitosis properties in a clinical trial and was safe. TRIAL REGISTRATION: The randomized controlled clinical trial was registered on Chinese Clinical Trial Registry (No. ChiCTR2300073816, Date: 21/07/2023).

Mediating role of systemic inflammation in the association between heavy metals exposure and periodontitis risk.

BACKGROUND: This study evaluated the mediating role of systemic inflammation in the association between exposure to heavy metals and periodontitis in a nationwide sample of adults. METHODS: Pooled cross-sectional data from the National Health and Nutrition Examination Survey (NHANES 2009-2014) were used (n = 8993). Periodontitis was defined by a full-mouth examination and classified as no/mild and moderate/severe (mod/sev) groups. Blood and urinary heavy metal levels were investigated, including cadmium (Cd), lead (Pb), and mercury (Hg). In addition, systemic inflammation was assessed using circulatory leukocyte counts and C-reactive protein (CRP) levels. RESULTS: Multivariable logistic regression analysis revealed the positive associations of blood and urinary levels of Cd and Pb with mod/sev periodontitis. In contrast,blood Hg levels did not show a significant association. The odds of having periodontitis were 1.233 and 1.311 times higher for each one-unit increment in Ln-transformed blood Cd (95% confidence interval [CI]: 1.109-1.371) and Pb (95% CI: 1.170-1.470), respectively. Mediation analysis suggested a 6.3% to 11.5% contribution of leucocyte counts in the association of blood Cd and Pb levels with periodontitis. Sensitivity analyses for urinary Cd levels yielded consistent mediating effects. However, no significant mediating effect of CRP was detected. CONCLUSION: Higher exposures to Cd and Pb were positively associated with periodontitis risk. These associations might be partially mediated by the elevated levels of leukocytes rather than CRP. Further longitudinal studies are needed to elucidate the discordant results of the systemic inflammatory biomarkers.

Short-chain fatty acid - A critical interfering factor for allergic diseases.

Allergy is a growing global public health problem with a high socio-economic impact. The incidence of allergic diseases is increasing year by year, which has attracted more and more attention. In recent years, a number of epidemiological investigations and gut microbiota studies have shown that gut microbiota dysbiosis is associated with an increased prevalence of various allergic diseases, such as food allergy, asthma, allergic rhinitis, and atopic dermatitis. However, the underlying mechanisms are complex and have not been fully clarified. Metabolites are one of the main ways in which the gut microbiota functions. Short-chain fatty acids (SCFAs) are the main metabolites of intestinal flora fermentation and are beneficial to human health. Studies have shown that SCFAs play an important role in maintaining intestinal homeostasis and regulating immune responses by recognizing receptors and inhibiting histone deacetylases, and are key molecules involved in the occurrence and development of allergic diseases. In addition, research on the regulation of gut microbiota and the application of SCFAs in the treatment of allergic diseases is also emerging. This article reviews the clinical and experimental evidence on the correlation between SCFAs and allergic diseases and the potential mechanisms by which SCFAs regulate allergic diseases. Furthermore, SCFAs as therapeutic targets for allergic diseases are also summarized and prospected.

Assessing the surveillance use of 2018 EFP/AAP classification of periodontitis: A validation study and clustering analysis.

BACKGROUND: The performance of the 2018 European Federation of Periodontology/American Academy of Periodontology (EFP/AAP) classification of periodontitis for epidemiology surveillance purposes remains to be investigated. This study assessed the surveillance use of the 2018 EFP/AAP classification and its agreement with the unsupervised clustering method compared with the 2012 Centers for Disease Control and Prevention(CDC)/AAP case definition. METHODS: Participants (n = 9424) in the National Health and Nutrition Examination Survey (NHANES) were staged by the 2018 EFP/AAP classification and classified into subgroups via k-medoids clustering. Concordance levels between periodontitis definitions and the clustering method were evaluated through the multiclass area under the receiver operating characteristic curve (multiclass AUC) among "periodontitis cases" and the general population, respectively. The multiclass AUC of the 2012 CDC/AAP definition versus clustering was used as a reference. The associations of periodontitis with chronic diseases were estimated using multivariable logistic regression. RESULTS: All the participants were identified as "periodontitis cases" by the 2018 EFP/AAP classification, and the prevalence of stage III-IV was 30%. The optimal numbers of clusters were three and four. The 2012 CDC/AAP definition versus clustering yielded a multiclass AUC of 0.82 and 0.85 among the general population and "periodontitis cases," respectively. The multiclass AUC of the 2018 EFP/AAP classification versus clustering was 0.77 and 0.78 for different target populations. Similar patterns prevailed in associations with chronic diseases between the 2018 EFP/AAP classification and clustering. CONCLUSIONS: The validity of the 2018 EFP/AAP classification was verified by the unsupervised clustering method, which performed better in distinguishing "periodontitis cases" than classifying the general population. For surveillance purposes, the 2012 CDC/AAP definition showed a higher agreement level with the clustering method than the 2018 EFP/AAP classification.

Socioecological determinants of child oral health-A scoping review.

OBJECTIVES: Child oral health is a result of interactions between multilevel influences within a complex system. Understanding those interactions informs conceptualizing a socioecological framework of important influences on oral health. This paper aimed to present a scoping review on the determinants of dental caries and their interactions in childhood and adolescence. METHODS: The two review questions were as follows: Which factors are determinants of child dental caries? and, How do determinants interact within and across socioecological levels? The three main electronic databases for biomedical records, PubMed, Web of Science and Scopus were searched, followed by reference check. The search and screening/selection procedures followed an a priori strategy and inclusion/exclusion criteria were specified in advance. The main components of the strategy were participants, concept and context. Following the final selection, eligible studies were assessed with quality appraisal tools for the risk of methodologic biases. Determinants reported in the included studies were then assigned to the micro-, meso-, exo- or macro-systems levels in a socioecological framework. Interactions between determinants were also identified and reported. RESULTS: A total of 100 studies were included after removal of duplicates, screening on the title/abstracts and full-text assessment among 3313 records initially identified. A higher number of studies included were cross-sectional studies published in recent years. The majority of determinants found to influence child dental health were assigned to microsystem level within the framework. However, determinants were found at all levels and interactions were reported within and between socioecological levels. Determinants identified in the scoping review represent factors at different socioecological levels that influence child oral health. CONCLUSION: Application of a socioecological model through a complex systems approach should lead to valid and robust progress towards practical solutions for better child oral health globally.

Application of multilevel models for predicting pain following root canal treatment.

OBJECTIVES: This study developed predictive models for one-week acute and six-month persistent pain following root canal treatment (RCT). An additional aim was to study the gain in predictive efficacy of models containing clinical factors only, over models containing sociodemographic characteristics. METHODS: A secondary data analysis of 708 patients who received RCTs was conducted. Three sets of predictors were used: (1) combined set, containing all predictors in the data set; (2) clinical set and (3) sociodemographic set. Missing data were handled by multiple imputation using the missing indicator method. The multilevel least absolute selection and shrinkage operator (LASSO) regression was used to select predictors into the final multilevel logistic models. Three measures, the area under the receiver operating characteristic curve (AUROC) and precision-recall curve (AUPRC) and calibration curves, were used to assess the predictive performance of the models. RESULTS: The selected-in factors in the final models, using LASSO regression, are related to pre- and intra-treatment clinical symptoms and pain experience. Predictive performance of the models remained the same with the inclusion (exclusion) of the socio-demographic factors. For predicting one-week outcome, the model built with combined set of predictors yielded the highest AUROC and AUPRC of 0.85 and 0.72, followed by the models built with clinical factors (AUROC = 0.82, AUPRC = 0.66). The lowest predictive ability was found in models with only sociodemographic characteristics (AUROC = 0.68, AUPRC = 0.40). Similar patterns were observed in predicting six-month outcome, where the AUROC for models with combined, clinical and sociodemographic sets of predictors were 0.85, 0.89 and 0.66, respectively, and the AUPRC were 0.48, 0.53 and 0.22, respectively. CONCLUSIONS: Clinical factors such as the severity and experience of pre-operative and intra-operative pain were discovered important to the subsequent development of pain following RCTs. Adding sociodemographic characteristics to the models with clinical factors did not change the models' predictive performance or the proportion of explained variance.

Serum antibodies to periodontal pathogens are related to allergic symptoms.

BACKGROUND: The association between periodontitis and allergic symptoms has been investigated. However, the difference in immune signatures between them remains poorly understood. This cross-sectional study assessed the relationship between serum immunoglobulin G (IgG) antibodies to periodontal pathogens and allergic symptoms in a nationwide population cohort. METHODS: Two phases of the Third National Health and Nutrition Examination Survey (NHANES III) were used as discovery dataset (n = 3700) and validation dataset (n = 4453), respectively. Based on the antibodies against 19 periodontal pathogens, we performed an unsupervised hierarchical clustering to categorize the population into three clusters. In the discovery dataset, cluster 1 (n = 2847) had the highest level of IgG antibodies, followed by clusters 2 (n = 588) and 3 (n = 265). Data on allergic symptoms (asthma, hay fever, and wheezing) were obtained using a self-reported questionnaire. Survey-weighted multivariable logistic regression evaluated the association between these clusters and allergic symptoms. RESULTS: In the discovery dataset, the participants with lower levels of antibodies to periodontal pathogens exhibited a higher risk of asthma (odds ratio [OR]cluster 3 vs. cluster 1 = 1.820, 95% confidence interval [CI]: 1.153-2.873) and wheezing (ORcluster 3 vs. cluster 1 = 1.550, 95% CI: 1.095-2.194) compared to those with higher periodontal antibodies, but the non-significant association with hay fever. Consistent results were found in the validation dataset. CONCLUSIONS: Serum IgG titers to periodontal pathogens were inversely associated with the risk of asthma and wheezing, suggesting the potentially protective role against allergic conditions.

Effect of different sweeteners on the quality, fatty acid and volatile flavor compounds of braised pork.

This study aimed to assess how several sweeteners (white sugar, Siraitia grosvenorii fruit, mogrosides, and stevia glycoside) affected the flavor, fatty acid composition, and quality of braised pork. The findings indicated that braised meat prepared with sweeteners differed from typical braised pork. When simmered for 60 min, the typical braised pork with white granulated sugar exhibited a significant cooking loss (CL) and little water content. Significantly more than in the group containing Siraitia grosvenorii, mogroside, and stevia glycoside, the Thiobarbituric acid (TBARS) value increased by 14.39% (P < 0.05). The sample in the group that included mogroside had a low CL rate. After 40 min of stewing, the lean pork has the highest L* value, but the 60-min stew sample is nicely colored and stretchy. Mogroside can prevent protein, and lipid oxidation, is thermally stable and reduces CL during stewing. Additionally, Siraitia grosvenorii and stevia glycosides help prevent oxidation from intensifying during stewing. When Siraitia grosvenorii is added, lipid oxidation is significantly inhibited, and stevia glycosides are more beneficial for enhancing meat color. With an increase in heating time, the fatty acids in braised pork reduced; the unsaturated fatty acid (UFA) of the Siraitia grosvenorii fruit (SF) and mg group also fell somewhat, and the UFA: SFA ratio was higher than that of the white sugar (WS) group. The SFA content of the braised meat in the stevia glycoside group was higher than that of the WS group. In all, 75 volatile flavor elements in braised pork were discovered by Gas chromatography-ion mobility spectrometry (GC-IMS). The sweetener increased alcohols, esters, and acids in the braised pork. As stewing time increased, ketones decreased, but aldehydes and esters increased. The pork formed antioxidant peptides with great nutritional value after cooking. Braised pork with mogroside and stevia glycoside additions primarily have some protein color protection and antioxidant effects. This study may offer fresh perspectives on applying natural sweeteners and enhancing braised pork's flavor.

Customized Barrier Membrane (Titanium Alloy, Poly Ether-Ether Ketone and Unsintered Hydroxyapatite/Poly-l-Lactide) for Guided Bone Regeneration.

Sufficient bone volume is indispensable to achieve functional and aesthetic results in the fields of oral oncology, trauma, and implantology. Currently, guided bone regeneration (GBR) is widely used in reconstructing the alveolar ridge and repairing bone defects owing to its low technical sensitivity and considerable osteogenic effect. However, traditional barrier membranes such as collagen membranes or commercial titanium mesh cannot meet clinical requirements, such as lack of space-preserving ability, or may lead to more complications. With the development of digitalization and three-dimensional printing technology, the above problems can be addressed by employing customized barrier membranes to achieve space maintenance, precise predictability of bone graft, and optimization of patient-specific strategies. The article reviews the processes and advantages of three-dimensional computer-assisted surgery with GBR in maxillofacial reconstruction and alveolar bone augmentation; the properties of materials used in fabricating customized bone regeneration sheets; the promising bone regeneration potency of customized barrier membranes in clinical applications; and up-to-date achievements. This review aims to present a reference on the clinical aspects and future applications of customized barrier membranes.

The Effect of Nonaugmentative Approaches in the Surgical Treatment of Peri-implantitis: A Systematic Review and Network Meta-analysis.

PURPOSE: This systematic review and Bayesian network meta-analysis (NMA) were performed to compare the clinical effects of nonaugmentative adjunctive approaches in the surgical treatment of peri-implantitis. MATERIALS AND METHODS: A systematic search of six electronic databases was performed up to June 20, 2020. Additional relevant literature was identified through gray literature and hand searches. Randomized controlled trials (RCTs) of surgical treatment of periimplantitis with nonaugmentative adjunctive approaches were included. Probing depth (PD) changes, marginal bone level (MBL) changes, and treatment success rates were extracted and assessed. Pairwise meta-analysis and Bayesian NMA were performed. This review was registered at PROSPERO (CRD42020191113). RESULTS: The search yielded 7,419 articles, of which 10 studies with 11 articles were included in the quantitative analysis. In the NMA of mechanical approaches and photodynamic therapy (PDT), compared with hand curettes, implantoplasty provided significant additional PD improvement at the 6-month follow-up evaluation (mean difference [MD]: 1.29; 95% confidence interval [CI]: 0.17, 2.38) and 12-month follow-up evaluation (MD: 1.39; 95% CI: 0.91, 1.74). In the NMA of antiseptics and systemic antibiotics, adjunctive use of antiseptics and/or systemic antibiotics did not provide significant improvement in PD or MBL. In the NMA of all adjunctive approaches, no significant differences were found in PD improvements. CONCLUSION: Within the limitations of this systematic review and NMA, implantoplasty is more effective than hand curettes in improving PD in the surgical treatment of peri-implantitis. Chemical antiseptics or systemic antibiotics have a limited effect on improving PD and MBL.

Periodontitis and cognitive impairment in older adults: The mediating role of mitochondrial dysfunction.

BACKGROUND: Increased attention has been focused on the associations of periodontal disease with the onset and progression of cognitive impairment. Although the associations are likely to be multifactorial, few studies have explored the role of mitochondrial dysfunction in the periodontitis-dementia link. METHODS: Cross-sectional data of 1,883 participants aged ≥60 years in the National Health and Nutrition Examination Survey 2011-2014 were analyzed. The following data were collected: 1) general information on sociodemographic, behavioral, and health-related factors; 2) periodontal status (mean attachment loss [AL] and mean probing depth [PD]); 3) mitochondrion-derived biomarker of mitochondrial dysfunction (blood sample concentration of methylmalonic acid [MMA]); 4) cognitive function (Consortium to Establish a Registry for Alzheimer's disease immediate recall [CERAD-IR] and delay recall [CERAD-DR], animal fluency test, and digit symbol substitution test [DSST]). Mediation analysis weighted for complex survey design was used to assess the effect of MMA on the association of periodontal status with cognitive function after adjusting for potential confounders. RESULTS: Participants with Stage III and IV periodontitis had lower scores on cognitive performance and higher MMA levels than those with Stages I/II periodontitis. Circulating MMA was significantly associated with CERAD-DR (weighted ß [SE] = -0.076 [0.011]) and DSST (weighted ß [SE] = -0.039 [0.009]), which mediated 9.9% and 6.0% of the total association of mean PD with cognitive function. Moreover, MMA mediated 11.7% and 5.8% of the association of mean AL with CERAD-DR and DSST, respectively. CONCLUSION: The findings suggest that MMA, a biomarker of mitochondrial dysfunction, plays a mediating role in the link between periodontitis and cognitive impairment in older adults aged ≥60 years.

Comparison of the Tree-Based Machine Learning Algorithms to Cox Regression in Predicting the Survival of Oral and Pharyngeal Cancers: Analyses Based on SEER Database.

This study aims to demonstrate the use of the tree-based machine learning algorithms to predict the 3- and 5-year disease-specific survival of oral and pharyngeal cancers (OPCs) and compare their performance with the traditional Cox regression. A total of 21,154 individuals diagnosed with OPCs between 2004 and 2009 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. Three tree-based machine learning algorithms (survival tree (ST), random forest (RF) and conditional inference forest (CF)), together with a reference technique (Cox proportional hazard models (Cox)), were used to develop the survival prediction models. To handle the missing values in predictors, we applied the substantive model compatible version of the fully conditional specification imputation approach to the Cox model, whereas we used RF to impute missing data for the ST, RF and CF models. For internal validation, we used 10-fold cross-validation with 50 iterations in the model development datasets. Following this, model performance was evaluated using the C-index, integrated Brier score (IBS) and calibration curves in the test datasets. For predicting the 3-year survival of OPCs with the complete cases, the C-index in the development sets were 0.77 (0.77, 0.77), 0.70 (0.70, 0.70), 0.83 (0.83, 0.84) and 0.83 (0.83, 0.86) for Cox, ST, RF and CF, respectively. Similar results were observed in the 5-year survival prediction models, with C-index for Cox, ST, RF and CF being 0.76 (0.76, 0.76), 0.69 (0.69, 0.70), 0.83 (0.83, 0.83) and 0.85 (0.84, 0.86), respectively, in development datasets. The prediction error curves based on IBS showed a similar pattern for these models. The predictive performance remained unchanged in the analyses with imputed data. Additionally, a free web-based calculator was developed for potential clinical use. In conclusion, compared to Cox regression, ST had a lower and RF and CF had a higher predictive accuracy in predicting the 3- and 5-year OPCs survival using SEER data. The RF and CF algorithms provide non-parametric alternatives to Cox regression to be of clinical use for estimating the survival probability of OPCs patients.

Fabrication of mechanically resistant superhydrophobic synthetic suede materials.

Functionalization of synthetic suede materials with excellent superhydrophobicity can expand their application ranges. Superhydrophobic synthetic suede was obtained by coating with polydimethylsiloxane (PDMS) and octadecyltrichlorosilane (OTS). Utilizing the synthetic suede effect of the fibrous rough structures in combination with the low surface energy micro-nano rough structure on fibers resulting from PDMS and OTS, the surface was easily turned superhydrophobic with self-cleaning properties. Abrasion tests showed that the superhydrophobic synthetic suede has excellent superhydrophobic performance after more than 2000 severe abrasion tests. This research provides a facile strategy for the preparation of practical superhydrophobic synthetic suede materials.

Changes in Lesional and Non-lesional Skin Microbiome During Treatment of Atopic Dermatitis.

The aim of this study was to evaluate changes in the skin surface microbiome in patients with atopic dermatitis during treatment. The effect of narrowband ultraviolet B phototherapy was also studied to determine the influence of exposure to ultraviolet. A total of 18 patients with atopic dermatitis were included in the study. Patients were divided into 2 groups based on treatment: 1 group treated with narrowband ultraviolet B phototherapy and topical corticosteroid, and the other group treated with topical corticosteroid only. Skin swabs and high-throughput sequencing of 16S ribosomal RNA bacterial genes were performed at 3 time-points. The microbial diversity of lesional skin increased greatly after treatment. The proportion of Staphylococcus aureus showed a significant positive correlation with eczema severity. In conclusion, a drastic increase in microbial diversity and decrease in S. aureus proportion were observed with eczema treatment. Narrowband ultraviolet B treatment did not exert additive effects on eczema improvement; however, it appeared to reduce the recurrence of eczema.

Prediction models for the incidence and progression of periodontitis: A systematic review.

AIMS: To comprehensively review, identify and critically assess the performance of models predicting the incidence and progression of periodontitis. METHODS: Electronic searches of the MEDLINE via PubMed, EMBASE, DOSS, Web of Science, Scopus and ProQuest databases, and hand searching of reference lists and citations were conducted. No date or language restrictions were used. The Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies checklist was followed when extracting data and appraising the selected studies. RESULTS: Of the 2,560 records, five studies with 12 prediction models and three risk assessment studies were included. The prediction models showed great heterogeneity precluding meta-analysis. Eight criteria were identified for periodontitis incidence and progression. Four models from one study examined the incidence, while others assessed progression. Age, smoking and diabetes status were common predictors used in modelling. Only two studies reported external validation. Predictive performance of the models (discrimination and calibration) was unable to be fully assessed or compared quantitatively. Nevertheless, most models had "good" ability to discriminate between people at risk for periodontitis. CONCLUSIONS: Existing predictive modelling approaches were identified. However, no studies followed the recommended methodology, and almost all models were characterized by a generally poor level of reporting.

The differential effect of basic fibroblast growth factor and stromal cell­derived factor­1 pretreatment on bone morrow mesenchymal stem cells osteogenic differentiation potency.

In situ tissue engineering has become a novel strategy to repair periodontal/bone tissue defects. The choice of cytokines that promote the recruitment and proliferation, and potentiate and maintain the osteogenic differentiation ability of mesenchymal stem cells (MSCs) is the key point in this technique. Stromal cell­derived factor­1 (SDF­1) and basic fibroblast growth factor (bFGF) have the ability to promote the recruitment, and proliferation of MSCs; however, the differential effect of SDF­1 and bFGF pretreatment on MSC osteogenic differentiation potency remains to be explored. The present study comparatively observed osteogenic differentiation of bone morrow MSCs (BMMSCs) pretreated by bFGF or SDF­1 in vitro. The gene and protein expression levels of alkaline phosphatase (ALP), runt related transcription factor 2 (Runx­2) and bone sialoprotein (BSP) were detected using reverse transcription­quantitative polymerase chain reaction and western blotting. The results showed that the expression of ALP mRNA on day 3, and BSP and Runx­2 mRNA on day 7 in the bFGF pretreatment group was significantly higher than those in SDF­1 pretreatment group. Expression levels of Runx­2 mRNA, and ALP and Runx­2 protein on day 3 in the SDF­1 pretreatment group were higher than those in the bFGF pretreatment group. However, there was no significant difference in osteogenic differentiation ability on day 14 and 28 between the bFGF­ or SDF­1­pretreatment groups and the control. In conclusion, bFGF and SDF­1 pretreatment inhibits osteogenic differentiation of BMMSCs at the early stage, promotes it in the medium phase, and maintains it in the later stage during osteogenic induction, particularly at the mRNA level. Out of the two cytokines, bFGF appeared to have a greater effect on osteogenic differentiation.

Low concentrations of TNF-α promote osteogenic differentiation via activation of the ephrinB2-EphB4 signalling pathway.

OBJECTIVES: Low concentrations of tumour necrosis factor-alpha (TNF-α) have been reported to promote osteogenic differentiation. In this study, a series of in vitro experiments was performed to investigate underlying molecular mechanisms involved. MATERIALS AND METHODS: MC3T3-E1 murine preosteoblasts were treated with TNF-α at doses of 0, 0.1 or 1 ng/mL. The ephrinB2-EphB4 signalling pathway was activated using ephrinB2-fc, or inhibited using lentiviruses encoding siRNAs specifically targeting EphB4. Cell proliferation/survival was evaluated using the Cell Counting Kit-8 (CCK-8) assay, and expression levels of Runx2, BSP, ephrinB2 and EphB4 were determined using RT-PCR and Western blotting. ALP activity in these cells was also determined, and mineral nodule formation was evaluated with alizarin red S staining. RESULTS: Low concentrations of TNF-α had no influence on cell proliferation/survival. However, expression levels of Runx2, BSP, ephrinB2 and EphB4, as well as ALP activity and mineral nodule formation, were significantly enhanced in MC3T3-E1 cells treated with low concentrations of TNF-α. Moreover, activation of the ephrinB2-EphB4 signalling pathway by ephrinB2-fc enhanced TNF-α-induced osteogenic differentiation, while down-regulation of EphB4 level reversed the positive effect of TNF-α. CONCLUSIONS: Low concentrations of TNF-α promoted osteogenic differentiation via activation of the ephrinB2-EphB4 signalling pathway.

Acellular dermal matrix loading with bFGF achieves similar acceleration of bone regeneration to BMP-2 via differential effects on recruitment, proliferation and sustained osteodifferentiation of mesenchymal stem cells.

New generation of barrier membranes has been developed, which not only act as barriers but also as delivery devices to release specific growth factors. This study observed biological behaviors of bone morrow mesenchymal stem cells (BMMSCs) pretreated by bFGF or BMP-2 in vitro and evaluated differential bone regeneration process induced by bFGF and BMP-2 loaded acellular dermal matrix (ADM) membrane using critical-size rat calvarial defect model in vivo. The results showed that the proliferation capability of BMMSCs pretreated by bFGF was stronger than that by BMP-2, while there was temporally differential effect of bFGF and BMP-2 pretreatment on MSC osteogenic differentiation potentials. During healing process of rat calvarial defects, 2-fold more CD34-/CD90+ MSCs in group of bFGF-ADM was observed than in any other treatment group at 2weeks. However, there were similar amount of new bone formation and expression of osteopotin in newly-formed bone tissue in groups of bFGF- and BMP-2-ADM at 8weeks, which were more than those in ADM alone and blank control. Taken together, bFGF-ADM guided similar bone regeneration to BMP-2 through more efficient recruitment of MSCs, and moreover, BMMSCs pretreated by bFGF showed stronger proliferation at 1-5days and osteogenic differentiation potentials at 14days compared with BMP-2 pretreatment.

[Effect of aspirin on cell biological activities in murine bone marrow stromal cells].

OBJECTIVE: To determine the effect of aspirin on cell proliferation, alkaline phosphatase (ALP) activity, cell cycle and apoptosis in murine bone marrow stromal cells, so as to explore an appropriate dose range to improve bone regeneration in periodontal treatment. METHODS: ST2 cells were stimulated with aspirin (concentrations of 1, 10, 100 and 1 000 µmol/L) for 1, 2, 3, 5 and 7 d. Cell proliferation was measured by methyl thiazolyl tetrazolium (MTT) assay. After ST2 cells were treated for 1, 3 and 7 d, ALP activity was measured by ALP kit, cell cycle and apoptosis were measured by flow cytometry (FCM) after treated for 48 h. RESULTS: MTT assays showed that various doses of aspirin have different effects on the cell growth. Briefly, lower concentrations (1, 10 µmol/L) of aspirin promoted the cell growth, the A value of 0, 1 and 10 µmol/L aspirin 7-day-treated cells were 0.313±0.012, 0.413±0.010 and 0.387±0.017 respectively (P <0.01 vs control), and so did the ALP level ([4.3±0.9], [6.0±0.3] and [7.7±0.4] µmol·min(-1)·g(-1), P <0.05 vs control), while higher concentrations, especially 1000 µmol/L of aspirin might inhibit the cell growth with time going, A value and ALP level were 0.267±0.016, (4.3±1.3) µmol·min(-1)·g(-1) respectively (P <0.05 vs control). Cell cycle analysis revealed no changes in comparison to control cells after treatment with 1 or 10 µmol/L aspirin, but it was observed that cell mitosis from S phase to G2/M phase proceeded at higher concentrations of 100 µmol/L aspirin, and the cell cycle in phase G0/G1 arrested at 1000 µmol/L. Parallel apoptosis/necrosis studies showed that the percentage of cells in apoptosis decreased dramatically at all doses of aspirin, the apoptosis rates of ST2 cells responded to 0, 1, 10, 100 and 1000 µmol/L aspirin were (11.50±0.90)%, (5.30±0.10)%, (5.50±0.10)%, (4.90±0.90)% and (7.95±0.25)% respectively (P<0.05 vs control). CONCLUSIONS: This study demonstrated that lower dosage of aspirin can promote ST2 cells growth, osteogenic activity and inhibit its apoptosis. Aspirin maybe used for the bone reconstruction with a proper concentration.