Applications of artificial intelligence for surgical extraction in stomatology: a systematic review.

OBJECTIVES: Artificial intelligence (AI) has been extensively used in the field of stomatology over the past several years. This study aimed to evaluate the effectiveness of AI-based models in the procedure, assessment, and treatment planning of surgical extraction. STUDY DESIGN: Following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a comprehensive search was conducted on the Web of Science, PubMed/MEDLINE, Embase, and Scopus databases, covering English publications up to September 2023. Two reviewers performed the study selection and data extraction independently. Only original research studies utilizing AI in surgical extraction of stomatology were included. The Cochrane risk of bias tool for randomized trials (RoB 2) was selected to perform the quality assessment of the selected literature. RESULTS: From 2,336 retrieved references, 35 studies were deemed eligible. Among them, 28 researchers reported the pioneering role of AI in segmentation, classification, and detection, aligning with clinical needs. In addition, another 7 studies suggested promising results in tooth extraction decision-making, but further model refinement and validation were required. CONCLUSIONS: Integration of AI in stomatology surgical extraction has significantly progressed, enhancing decision-making accuracy. Combining and comparing algorithmic outcomes across studies is essential for determining optimal clinical applications in the future.

A comprehensive biomechanical evaluation of length and diameter of dental implants using finite element analyses: A systematic review.

Background: With a wide range of dental implants currently used in clinical scenarios, evidence is limited on selecting the type of dental implant best suited to endure the biting force of missing teeth. Finite Element Analysis (FEA) is a reliable technology which has been applied in dental implantology to study the distribution of biomechanical stress within the bone and dental implants. Purpose: This study aimed to perform a systematic review to evaluate the biomechanical properties of dental implants regarding their length and diameter using FEA. Material and methods: A comprehensive search was performed in PubMed/MEDLINE, Scopus, Embase, and Web of Science for peer-reviewed studies published in English from October 2003 to October 2023. Data were organized based on the following topics: area, bone layers, type of bone, design of implant, implant material, diameter of implant, length of implant, stress units, type of loading, experimental validation, convergence analysis, boundary conditions, parts of Finite Element Model, stability factor, study variables, and main findings. The present study is registered in PROSPERO under number CRD42022382211. Results: The query yielded 852 results, of which 40 studies met the inclusion criteria and were selected in this study. The diameter and length of the dental implants were found to significantly influence the stress distribution in cortical and cancellous bone, respectively. Implant diameter was identified as a key factor in minimizing peri-implant stress concentrations and avoiding crestal overloading. In terms of stress reduction, implant length becomes increasingly important as bone density decreases. Conclusions: The diameter of dental implants is more important than implant length in reducing bone stress distribution and improving implant stability under both static and immediate loading conditions. Short implants with a larger diameter were found to generate lower stresses than longer implants with a smaller diameter. Other potential influential design factors including implant system, cantilever length, thread features, and abutment collar height should also be considered in future implant design as they may also have an impact on implant performance.

Association among physical activity, anxiety and oral health status in Chinese university students: A cross-sectional study.

Background: Evidence is limited regarding the relationship among physical activity, anxiety, and oral health in Chinese university students. This cross-sectional investigation aimed to assess the potential relationship between physical activity, anxiety, and oral health conditions among university students in China. Methods: An online questionnaire measuring physical activity, anxiety status, and oral health condition was completed by 1604 university students. The International Physical Activity Questionnaire Short Form (IPAQ-SF) and Generalized Anxiety Disorder-7 (GAD-7) were selected to evaluate physical activity and anxiety, respectively. Oral health condition was assessed through several self-reported variables, including self-reported toothache, gingival bleeding, frequency of tooth brushing, and use of dental floss. Multivariate logistic regression was performed to analyze the underlying relationship between outcome variables. The control variables included age, height, weight, gender, whether only one-child, education level, parental education level, smoking status, drinking habits, and length of sleep. Path analysis was conducted to disentangle the association between physical activity, anxiety, and oral health conditions. Results: Among 1604 university students, 666 (41.5 %) were males and 938 (58.5 %) were females, with an average of 21.9 ± 2.8 years. Only 833 (51.9 %) reported sufficient physical activity, while 684 (42.6 %) of the subjects displayed varying degrees of anxiety. Self-reported gingival bleeding was associated with insufficient physical activity (OR = 1.25; 95%CI: 1.02-1.55), anxiety (OR = 0.45; 95%CI: 0.27-0.74), frequency of tooth brushing (OR = 0.75; 95%CI: 0.60-0.95) and use of dental floss (OR = 0.75; 95%CI: 0.59-0.96), while toothache was not directly influenced by the physical activity and anxiety among university students. Anxiety markedly mediated the relationship between physical activity and oral health conditions. Conclusions: Anxiety was considered a factor associated with the level of physical activity, tooth brushing habits, and self-reported gingival bleeding among university students. Further investigations are required to elucidate whether oral health conditions could be enhanced through the improvement of anxiety and physical activity.

The underlying relationship between exercise and the prevalence of periodontitis: a systematic review and meta-analysis.

BACKGROUND: Although exercise has been proposed as an effective intervention for various lifestyle-related diseases and pathological scenarios, few researches assessed the impact of taking exercise on the prevalence of periodontitis. PURPOSE: This study aimed to perform a comprehensive literature review and meta-analysis from both observational and intervention studies to explore the relationship between exercise and periodontitis and to provide references for future intervention programs aimed at preventing periodontitis. METHOD: A systematic literature search was conducted in PubMed/MEDLINE, Web of Science, Cochrane Library, and Scopus for peer-reviewed studies published in English From January 1993 to January 2023 according to the PRISMA guidelines. Articles were selected if subjects were human and studies evaluating the association between exercise and periodontitis. RESULTS: 4098 references were retrieved. After screening the results, 30 studies were selected. Of these, 20 studies indicated an inverse association between exercise and periodontitis, while the remaining 10 did not reach conclusive findings. The meta-analysis demonstrated a risk ratio of 0.84 (95%CI: 0.77, 0.91) between the active group and the inactive group (P < 0.01), which indicated an inverse relationship between exercise and periodontitis. CONCLUSION: Overall, the increase in exercise presents an inverse association with the presence and severity of periodontitis. Accordingly, taking exercise might be a potential approach that contributes to improvements in periodontitis.

Potential of periosteal cells in bone and cartilage regeneration: a systematic review.

Introduction: The unavailability of adequate human primary cells presents multiple challenges in terms of bone and cartilage regeneration and disease modeling experiments in vitro. Periosteal cells (PCs), which represent promising skeletal stem cell sources, could be a promising strategy in tissue engineering. The present study aimed to summarize the characteristics of PCs to investigate the efficacy of these cells in bone and cartilage regeneration in different models, paying special attention to the comparison of bone marrow stromal cells (BMSCs). Methods: A comprehensive literature search was conducted in Embase, PubMed/MEDLINE, Web of Science, and Scopus for articles published in English until April 2023. Only original researches in which PCs were employed for bone or cartilage regeneration experiments were included. Results: A total of 9140 references were retrieved. After screening the results, 36 publications were considered to be eligible for inclusion in the present literature review. Overall, PCs demonstrated beneficial bone and cartilage regenerative efficacy compared to the bare scaffold since almost all included studies reported positive results. The 9 studies assessing the differences in bone formation capacity between PCs and BMSCs indicated that PCs exhibited stronger in vivo osteogenic differentiation capabilities compared to BMSCs, while the other study demonstrated stronger chondrogenic potential of BMSCs. Discussion: PCs demonstrated beneficial to bone regenerative efficacy compared to the bare scaffold with a low risk of most studies included. However, the cartilage formation capacity of BMSCs still needs to be investigated due to the limited research available and the certain risk of bias. PCs exhibited higher osteogenic capabilities compared to BMSCs in combination with various scaffolds in vivo with good evidence. Further researches are needed to elucidate the comparative benefits of cartilage regeneration. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023411522, CRD42023411522.

Accuracy of intraoral scanning versus conventional impressions for partial edentulous patients with maxillary defects.

This study aimed to evaluate the accuracy of digital dental impressions obtained by intraoral scanning (IOS) for partial edentulous patients with maxillary defects by comparing them with conventional impression techniques. Ten subjects underwent an experimental procedure where three ceramic blocks were affixed to the healthy palate mucosa. Digital dental impressions were captured using IOS and subsequently imported into software. Conventional impressions obtained by silicone rubber were also taken and scanned. Linear distance and best-fit algorithm measurements were performed using conventional impression techniques as the reference. Twenty impressions were analyzed, which included 30 pairs of linear distances and 10 best-fit algorithm measurements. Regarding linear distance, paired two-sample t-test demonstrated no significant differences between IOS and model scanning in groups A and C, whereas significant differences were found in group B (P < 0.05). Additionally, ANOVA revealed significant differences among the groups (P < 0.05). No significant differences were found for the best-fit algorithm measurement of the dentition. IOS can provide accurate impressions for partial edentulous patients with maxillary defects and its accuracy was found to be comparable with conventional impression techniques. A functional impression may be needed to ensure accurate reproduction of soft and hard tissues in defect or flap areas.

Effectiveness of interventions to reduce aerosol generation in dental environments: A systematic review.

Certain dental procedures produce high levels of aerosols containing pathogenic microorganisms, posing a risk for the transmission of infections in dental settings. This study aimed to assess the effectiveness of various aerosol mitigation interventions during clinical dental procedures in real-world environments. A systematic literature search was conducted in PubMed/MEDLINE, Scopus, Web of Science, and Embase for English studies up to March 2023 according to the PRISMA guidelines. Only peer-reviewed controlled clinical trials (CCT) or randomized controlled trials (RCT) studies involving human subjects were included. The risk of bias of selected researches were evaluated by two independent authors using the Cochrane Collaboration tool. The literature search yielded 3491 articles, of which 42 studies met the inclusion criteria and were included in this study. Most studies evaluated bacterial contamination in bio-aerosols, while the viral and fungal contamination was assessed in only three studies. Overall, various approaches have been applied in reducing aerosol contamination in clinical scenarios, including high-volume evacuators (HVE), mouse rinses and rubber dams, air cleaning systems, and high-efficiency particulate air (HEPA) filters. The available evidence suggests that various aerosol mitigation strategies could be implemented to decrease the risk of cross-infection during clinical dental procedures in real-world environments. However, further clinical trials are necessary to establish statistical validity in measuring aerosol contamination and mitigation, as well as to evaluate the risk of infection transmission for viral and fungal contamination.

Characterization and potential of periosteum-derived cells: an overview.

As a thin fibrous layer covering the bone surface, the periosteum plays a significant role in bone physiology during growth, development and remodeling. Over the past several decades, the periosteum has received considerable scientific attention as a source of mesenchymal stem cells (MSCs). Periosteum-derived cells (PDCs) have emerged as a promising strategy for tissue engineering due to their chondrogenic, osteogenic and adipogenic differentiation capacities. Starting from the history of PDCs, the present review provides an overview of their characterization and the procedures used for their isolation. This study also summarizes the chondrogenic, osteogenic, and adipogenic abilities of PDCs, serving as a reference about their potential therapeutic applications in various clinical scenarios, with particular emphasis on the comparison with other common sources of MSCs. As techniques continue to develop, a comprehensive analysis of the characterization and regulation of PDCs can be conducted, further demonstrating their role in tissue engineering. PDCs present promising potentials in terms of their osteogenic, chondrogenic, and adipogenic capacities. Further studies should focus on exploring their utility under multiple clinical scenarios to confirm their comparative benefit over other commonly used sources of MSCs.

Association between psychological stress, anxiety and oral health status among college students during the Omicron wave: a cross-sectional study.

BACKGROUND: Within 3 years of the COVID-19 pandemic, increasing interest has been given to its potential influence on health status due to lockdowns caused by the pandemic. However, the impact is inadequately understood, especially for college students. This study aimed to investigate the potential association between psychological stress, anxiety and oral health of college students during the Omicron wave of the COVID-19 pandemic. METHODS: An online survey with measurements of psychological stress, anxiety and oral health was completed by 1770 Chinese college students. The Perceived Stress Scale-14 (PSS-14) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure psychological stress and anxiety, respectively. Oral health status was self-reported including toothache, gingival bleeding, and oral ulcer. Multivariable logistic regressions were performed to determine underlying associations for outcome variables. Structural equation modeling (SEM) was performed to confirm the relationship between mental and oral health status. RESULTS: Of the 1770 subjects, 39.2% presented high psychological stress and only 41.2% expressed no anxiety. A significant association was found between psychological stress, anxiety and oral health status. Anxiety has significant impacts on toothache (OR = 0.36; 95%CI: 0.23-0.55; p < 0.01), gingival bleeding (OR = 0.43; 95%CI: 0.29-0.65; p < 0.01), and oral ulcer (OR = 0.54; 95%CI: 0.36-0.80; p < 0.01). Anxiety significantly mediated the association between psychological stress and self-reported oral symptoms. CONCLUSIONS: Anxiety may be a significant risk indicator for mental health among college students and demonstrates a significant relationship with the occurrence of self-reported oral symptoms. Concerns about academic and life changes caused by the pandemic were the two most significant sources of stress.

Influence of wearing mouthguards on performance among athletes: A systematic review.

OBJECTIVES: While the use of mouthguards is well established to prevent orofacial and dental trauma occurrence, limited evidence exists regarding their influence on athletic performance. The objective of this study was to conduct a systematic review of the literature to assess the effect of wearing mouthguards on athletic performance. DESIGN: Systematic review. METHODS: An extensive search was performed in the databases of PubMed/MEDLINE, Embase, Scopus and Cochrane Library for studies published up to August 2022. Only peer-reviewed studies involving humans in vivo and investigating the use of mouthguards on performance among athletes were included. Quality assessment was performed using the Cochrane Collaboration's risk of bias tool. RESULTS: The initial query yielded 4785 citations, of which 41 studies met the inclusion criteria, comprising a total of 852 athletes. Overall, wearing mouthguards was found to improve athletic performance compared to the control group (without mouthguards). Custom-made mouthguards were found to be more effective in enhancing athletic performance compared to other types of mouthguards. CONCLUSIONS: Wearing mouthguards should be advocated by athletes not only for the prevention of orofacial and dental trauma but also for their potential improvements in athletic performance in specific actions. However, caution must be exercised in interpreting these findings due to the variability in outcome measures and the lack of important methodological details.

A Comprehensive Analysis of Clinical Crowns in Young of Han Nationality with Normal Occlusion Using Intraoral Scanning.

Background: The measurement and analysis of clinical crowns play a crucial role in stomatology, anthropology, and studies of genetic and environmental variables in oral and maxillofacial development. Purpose: The objective of the present study was to measure the parameters of clinical crowns of permanent dentition in youth of Han nationality using intraoral scanning and identify potential influencing factors. Materials and Methods: A total of 100 subjects (50 males and 50 females) of Han nationality aged 18-24 with normal occlusion were selected. An intraoral scanner was used to obtain the digital dental impressions, and Materialise Magics 21 software was used to measure the mesiodistal diameter (MDD), buccolingual diameter (BLD), height, mesiodistal angle (MDA), and vestibulo-oral angle (VOA) of clinical crowns. The central height was calculated based on the height of clinical crowns. SPSS 27.0 software was used for statistical analysis. The two-independent-samplet-test was used to assess discrepancies in clinical crowns between males and females. The paired t-test was used to determine differences between antimetric pairs of clinical crowns within the same arch. The repeatability of intraoral scanning was tested using the paired t-test between two measurements at one-month intervals. The overall estimated effect was considered significant where P < 0.05. Results: The MDD, BLD, height, MDA, and VOA of clinical crowns in the youth of Han nationality were measured, and the central height was calculated. No significant difference was found in terms of MDA and VOA between genders and antimetric pairs within the same arch. Regarding the distance parameters, the MDD, BLD, and height of clinical crowns in males were significantly larger than those in females (MDD: U1, U3, U7, L2, L3, L6, and L7: P < 0.01; BLD: U1: P=0.02; U3-U7 and L1-L7: P < 0.01; height: U2: P=0.03; and U1, U3-U7, and L3-L7: P < 0.01). No significant difference was found in clinical crowns between antimetric pairs within the same arch. Intraoral scanning demonstrated good repeatability in the measurement of clinical crowns. Conclusions: Apart from MDA and VOA, the parameters of clinical crowns in males were significantly larger than in females. Antimetric pairs of clinical crowns within the same arch demonstrated similar tooth dimensions. In future clinical practice and scientific research in the oral and maxillofacial region, a comprehensive design of sexual and ethnic characteristics should be considered.

Clinical outcomes of titanium-zirconium alloy narrow-diameter implants for single-crown restorations: a systematic review and meta-analysis.

Evidence is limited on whether titanium-zirconium alloy, narrow-diameter implants (Ti-Zr NDIs) have promising clinical outcomes when used to support single crowns. The purpose of this systematic review and meta-analysis was to evaluate clinical evidence, including survival rates, success rates, and marginal bone loss (MBL) on Ti-Zr NDIs that support single crowns. An extensive search was performed in the databases of PubMed/MEDLINE, Scopus, Embase, and the Cochrane Library for studies published in English up to April 2022. Only peer-reviewed clinical studies with at least 10 patients and a follow-up time of at least 12 months were included. Risk of bias in each study was assessed and data extraction was carried out independently by two reviewers. The outcome variables were survival rates, success rates, and MBL. The search returned 779 results. Eight studies were identified for qualitative analysis and seven for quantitative synthesis. Overall, a total of 256 Ti-Zr NDIs were included. Cumulative implant survival rates and success rates were 97.5% (95% confidence interval (CI): 94.5% to 98.9%) and 97.2% (95% CI: 94.2% to 98.7%), respectively, over a maximum follow-up period of 36 months, with no difference between Ti-Zr NDIs and commercial pure titanium (cpTi) implants. Cumulative mean (SD) MBL was 0.44 (0.04) mm (95% CI: 0.36 to 0.52) after one year. Meta-analysis of MBL indicated a mean difference of 0.02 mm (95% CI: -0.23 to 0.10), with no differences between Ti-Zr NDIs and cpTi implants. Short-term results of Ti-Zr NDIs for single-crown restorations are quite promising, although the number of published studies and follow-up periods are insufficient to determine the real benefit for single crowns. Long-term, follow-up clinical studies are needed to verify the excellent clinical performance of Ti-Zr NDIs.

Self-assembled human placental model from trophoblast stem cells in a dynamic organ-on-a-chip system.

The placental barrier plays a key role in protecting the developing fetus from xenobiotics and exchanging substances between the fetus and mother. However, the trophoblast cell lines and animal models are often inadequate to recapitulate the key architecture and functional characteristics of human placental barrier. Here, we described a biomimetic placental barrier model from human trophoblast stem cells (hTSCs) in a perfused organ chip system. The placental barrier was constructed by co-culture of hTSCs and endothelial cells on the opposite sides of a collagen-coated membrane on chip. hTSCs can differentiate into cytotrophoblasts (CT) and syncytiotrophoblast (ST), which self-assembled into bilayered trophoblastic epithelium with placental microvilli-like structure under dynamic cultures. The formed placental barrier displayed dense microvilli, higher level secretion of human chorionic gonadotropin (hCG), enhanced glucose transport activity. Moreover, RNA-seq analysis revealed upregulated ST expression and activation of trophoblast differentiation-related signalling pathways. These results indicated the key role of fluid flow in promoting trophoblast syncytialization and placental early development. After exposure to mono-2-ethylhexyl phthalate, one of the endocrine disrupting chemicals, the model showed inhibited hCG production and disturbed ST formation in trophoblastic epithelium, suggesting impaired placental structure and function elicited by environmental toxicants. Collectively, the hTSCs-derived placental model can recapitulate placenta physiology and pathological response to external stimuli in a biomimetic manner, which is useful for the study of placental biology and associated diseases.

Evaluation of the accuracy of T-scan system and Cerec Omnicam system used in occlusal contact assessment.

Purpose: The objective of the present study was to determine the accuracy of T-scan system and Cerec Omnicam system with respect to the evaluation of occlusal contact by quantitatively comparing the occlusal contact areas and the overlapping ratios of occlusal contact areas obtained from these systems. Material and methods: The occlusal contact of 20 adolescents with normal occlusion was measured with the T-scan system and the Cerec Omnicam system, respectively. The occlusal contact areas in the intercuspal position were then quantified with Adobe Photoshop CS6 Software. The same procedure was repeated for each subject using with 8 µm articulating paper as the control group. The overlapping ratio of T-scan system and Cerec Omnicam system was calculated respectively, which is defined as the ratio of overlapping areas comparing with those obtained from articulating paper. To examine the accuracy of T-scan system and Cerec Omnicam system, the Paired t-test was applied. The reproducibility of T-scan system was evaluated with Wilcoxon matched-pairs signed-ranks test by comparing the occlusal contact areas between two repeated measurements. In all statistical analysis, the level of significance was set to α = 0.05. Results: Results demonstrated measured occlusal contact areas were significantly different between those obtained between T-scan system and Cerec Omnicam system (P < 0.05). The tooth position of two-dimensional virtual dental arch established by T-scan system based on the width of the central incisor was in disagreement with the actual tooth position. The overlapping ratios obtained from Cerec Omnicam system were higher than those obtained from the T-Scan system (P < 0.05). The sensitivity of T-Scan system in anterior teeth area decreased when sensors are used more than once (P < 0.05). Conclusions: In the intercuspal position, the accuracy of Cerec Omnicam system for occlusal contact assessment is higher than that of T-scan system. The T-scan system demonstrates good reproducibility in the premolar region and the molar region, but poor reproducibility in the anterior teeth region. Clinical implications: In the intercuspal position, Cerec Omnicam system is more accurate than T-scan system, which can quantitatively analyze occlusal relationship in terms of number, position, size and distribution of occlusal contact points. When evaluating occlusal contacts, the accuracy of T-scan system in anterior teeth region is significantly lower than that of premolar and molar regions.

Accuracy of three-dimensional optical devices for facial soft-tissue measurement in clinical practice of stomatology: A PRISMA systematic review.

BACKGROUND: The accuracy of 3-dimensional (3D) optical devices for facial soft-tissue measurement is essential to the success of clinical treatment in stomatology. The aim of the present systematic review was to summarize the accuracy of 3D optical devices used for facial soft-tissue assessment in stomatology. METHODS: An extensive systematic literature search was performed in the PubMed/MEDLINE, Embase, Scopus and Cochrane Library databases for studies published in the English language up to May 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Peer-reviewed journal articles evaluating the facial soft-tissue morphology by 3D optical devices were included. The risk of bias was performed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2 guidelines by the 2 reviewers. The potential publication bias was analyzed using the Review Manager software. RESULTS: The query returned 1853 results. A total of 38 studies were included in this review. Articles were categorized based on the principle of devices: laser-based scanning, structured-light scanning, stereophotogrammetry and red, green, blue-depth camera. CONCLUSION: Overall, the 3D optical devices demonstrated excellent accuracy and reliability for facial soft-tissue measurement in stomatology. red, green, blue-depth camera can collect accurate static and dynamic 3D facial scans with low cost and high measurement accuracy. Practical needs and availability of resources should be considered when these devices are used in clinical settings.

Brain organoid-on-chip system to study the effects of breast cancer derived exosomes on the neurodevelopment of brain.

Early human brain development can be affected by multiple prenatal factors that involve chemical exposures in utero, maternal health characteristics such as psychiatric disorders, and cancer. Breast cancer is one of the most common cancers worldwide arising pregnancy. However, it is not clear whether the breast cancer might influence the brain development of fetus. Exosomes secreted by breast cancer cells play a critical role in mediating intercellular communication and interplay between different organs. In this work, we engineered human induced pluripotent stem cells (hiPSCs)-derived brain organoids in an array of micropillar chip and probed the influences of breast cancer cell (MCF-7) derived-exosomes on the early neurodevelopment of brain. The formed brain organoids can recapitulate essential features of embryonic human brain at early stages, in terms of neurogenesis, forebrain regionalization, and cortical organization. Treatment with breast cancer cell derived-exosomes, brain organoids exhibited enhanced expression of stemness-related marker OCT4 and forebrain marker PAX6. RNA-seq analysis reflected several activated signaling pathways associated with breast cancer, medulloblastoma and neurogenesis in brain organoids induced by tumor-derived exosomes. These results suggested that breast cancer cell-derived exosomes might lead to the impaired neurodevelopment in the brain organoids and the carcinogenesis of brain organoids. It potentially implies the fetus of pregnant women with breast cancer has the risk of impaired neurodevelopmental disorder after birth.

[Recent advances in isolation and detection of circulating tumor cells with a microfluidic system].

The isolation and analysis of circulating tumor cells (CTCs) is an important issue in tumor research. CTCs in peripheral blood, which are important biomarkers of liquid biopsy, are closely related to the occurrence of cancer and are used to monitor the effect of treatment on cancer patients. However, the number of CTCs in the blood samples of cancer patients is very low, usually being present at only 0-10 CTCs/mL. Therefore, prior to the detection of CTCs, it is important to preprocess clinical blood samples for efficient separation and enrichment. With the advantages of low sample consumption, high separation efficiency, ease of automation and integration, microfluidic chips can be a suitable platform for the isolation of CTCs. In the last few years, CTC separation and detection using microfluidic chips have developed rapidly, and a variety of detection methods have been developed. According to the technical principle used, microfluidics for CTC separation can be divided into biological property-based methods and physical property-based methods. The biological property-based methods mainly depend on the interaction between the antigen and antibody, or the specific binding of the aptamer and target. These methods have high selectivity but low efficiency and recovery rates. Physical separation is based on the physical properties of CTCs such as their size, density, and dielectric properties. For example, CTCs can be blocked or captured by the microstructure in the channels of microfluidic chips, sorted by external physical fields (acoustic, electrical, magnetic), or screened by micro-scale hydrodynamics. Physical property-based methods generally have a higher flux but lower separation purity. However, the advantages of biological property-based methods and physical property-based methods can be integrated to provide microfluidic chips having better separation performance. In addition to the direct positive enrichment of CTCs, a negative enrichment strategy can also be adopted. The influence of direct screening on the activity of CTCs can be avoided by selectively removing white blood cells. In this paper, recent advances in microfluidics utilized in the isolation of CTCs, including physical and immune methods and positive and negative enrichment, are reviewed. We summarized the technical principles, detection methods, and research progress in CTC separation and detection using microfluidic chips. Developing trends in microfluidics for CTC separation and analysis are also discussed.

Simple and fast isolation of circulating exosomes with a chitosan modified shuttle flow microchip for breast cancer diagnosis.

Tumor-derived exosomes have been recognized as promising biomarkers for early-stage cancer diagnosis, tumor prognosis monitoring and individual medical treatment. However, it is a huge challenge to separate exosomes from trace biological samples in clinics for disease diagnosis. Herein, we propose a simple, quick, and label-free method for isolating circulating exosomes from serum of patients. The strategy synergistically integrates chitosan electrostatic-adsorption, micro-patterned substrates, and microfluidic shuttle flow control to enable the capture/release of circulating exosomes in a simple manner. Using this microchip, we can isolate exosomes from trace samples (10 µl) with relative purity over 90% and high RNA recovery ratio over 84% within 15 minutes, which is impossible for traditional ultracentrifugation methods. We then validate the application of the microchip using 24 serum samples from clinical breast cancer and breast fibroma patients. The isolated exosomes are subjected to miRNA sequencing and RT-PCR, followed by pathway prediction analysis. The results showed that exosomes were relevant to the invasion and metastasis of breast cancer cells and hsa-miR-18a-3p might have the potential to become a new biomarker for distinguishing breast cancer from breast fibroma (AUC = 0.83, P value = 0.019). This established method is simple, quick and easy to operate with integration. And it may pave a new way for clinical research on exosomes and tumor relevant diagnosis.

[Influence of canine vertical position on smile esthetic perceptions by using 3D digital facial reconstruction].

PURPOSE: To verify the impact of alterations in the vertical position of maxillary canine on smile esthetic perceptions, in order to find an optimal canine position. METHODS: A volunteer's dentition and facial images were scanned by intra-oral scanning and three-dimensional facial scanning, which were then calibrated. In virtue of dental computer-aided design software, the canine vertical positions were symmetrically modified in a variable of 0.5 mm, creating 4 new 3D virtual digital smile faces varying from 1.0 mm of intrusion to 1.0 mm of extrusion. A total of 5 3D virtual digital smile faces were evaluated from the front and 45°to the right sides by 60 dentists and 60 laypersons on a visual analog scale. The data were input into SPSS 20.0 software package, ANOVA of repeated measurement was used to compare the differences in the assessment scores between two groups and rank sum test was used to analyze the differences from different evaluation angles. RESULTS: Alterations in the vertical position of maxillary canine had significant influence on the esthetic evaluation of the smile(P<0.05); there was significant difference between the dentists' and laypersons' esthetic evaluations after the canine vertical position being modified(P<0.05), there was no significant difference on the evaluations of smile esthetics from different evaluation perspectives(P>0.05). CONCLUSIONS: The most attractive smile was the one with canine cusp 0.5 mm vertically higher than the incisal edge of the lateral incisor. The smile is not attractive when the cusp of canine is vertically lower than the incisal edge of lateral incisor. These results can be used as references in the esthetic treatment planning for anterior maxillary teeth.

Magnetic solid-phase extraction using sulfur-containing functional magnetic polymer for high-performance liquid chromatography-inductively coupled plasma-mass spectrometric speciation of mercury in environmental samples.

1,2-Ethanedithiol was firstly involved in preparing sulfur-containing functional magnetic polymer material of Fe3O4@SiO2@ glycidyl methacrylate (GMA)-S-SH. The prepared Fe3O4@SiO2@GMA-S-SH magnetic nanoparticles (MNPs) show better adsorption capacity and adsorption/desorption dynamics for mercury species than other -SH functional materials due to the high affinity of both thioether and thiol group towards mercury. A new method of magnetic solid phase extraction (MSPE) using Fe3O4@SiO2@GMA-S-SH as sorbents combined with high performance liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) was developed for the analysis of trace Hg2+, methylmercury (MeHg+) and phenylmercury (PhHg+). Variables affecting the simultaneous extraction of three target mercury species were investigated. It was found that Hg2+, MeHg+ and PhHg+ in 200 mL of water sample could be quantitatively adsorbed within 5 min and eluted by 0.5 mL 0.1 mol L-1 nitric acid and 4% thiocarbamide in 2 min. The developed method has high actual enrichment factors of 367, 380, 329-fold for Hg2+, MeHg+ and PhHg+, respectively. The detection limits were 0.40, 0.49 and 1.4 ng L-1 with the relative standard deviations (n = 5, inter-day) of 7.4, 8.1 and 8.3% for Hg2+, MeHg+ and PhHg+, respectively. The accuracy of the method was validated by the analysis of the Certified Reference Materials of GSS-11 soil, GSS-13 soil, GSB21 rice and DORM-2 fish. The established method was successfully used for the mercury speciation in farmland water, soil and rice samples collected from Wanshan, China, and satisfactory recoveries (84.3-116%) were obtained for the spiked samples.