Temporal stability of tongue microbiota in older patients - A pilot study

Background/purpose

Healthy states of human microbiota depend on a stable community of symbiotic microbes irrespective of external challenges from the environment. Thus, long-term stability of the oral microbiota is of importance, particularly for older patient populations.

Materials and methods

We used next-generation sequencing (NGS) to examine the tongue microbiota of 18 individuals receiving long-term care over a 10-month period.

Results

Beta diversity analysis demonstrated temporal stability of the tongue microbiota, as microbial compositions from all time points were indistinguishable from each other (P = 0.0887). However, significant individual variation in microbial composition (P = 0.0001) was observed, underscoring the presence of a unique microbial profile for each patient.

Conclusion

The temporal dynamics of tongue microbiota exhibit long-term stability, providing diagnostic implications for oral diseases within older patient populations.

Current prospect of dental zirconia recycling: A scoping review

PURPOSE

This scoping review aimed to identify and discuss the recyclability of dental zirconia residuals along with the factors influencing the properties of dental recycled zirconia.

STUDY SELECTION

In vitro studies written in both English and Chinese that evaluated the recyclability of dental zirconia residue were selected. A literature search was conducted in Medline, PubMed, Web of Science, and Cochrane Library databases with no restrictions on the publication year.

RESULTS

Sixteen studies were included in this review. Residual dental zirconia can be recycled. Cold isostatic pressing improved the density of recycled zirconia compared with uniaxial pressing. Recycled zirconia powder with fine particles enhanced the performance of recycled zirconia compared with coarse particles. A presintering temperature of 950 to 1100°C was suitable for preparing recycled zirconia presintered bodies. Recycled zirconia may require a higher sintering temperature (≥1500°C) compared with commercially available zirconia. Additionally, recycled zirconia powder can enhance the properties of polymethylmethacrylate as a reinforcing filler and can be combined with alumina powder to obtain an alumina/zirconia composite material.

CONCLUSIONS

Despite a limited body of literature, the recycling and reutilization of dental zirconia residuals are feasible and reliable, and can reduce economic and environmental losses. Nevertheless, several factors influence the recycling effect, including the particle size, molding techniques, and sintering parameters. In addition, recycled zirconia powder can act as a reinforcing filler, potentially enhancing the mechanical properties of other materials. To realize commercially viable recycled zirconia materials, further studies are essential to comprehensively explore and understand their recycling performance.

Nanoclay-Modified Hyaluronic Acid Microspheres for Bone Induction by Sustained rhBMP-2 Delivery

Microspheres (MSs) are ideal candidates as biological scaffolds loading with growth factors or cells for bone tissue engineering to repair irregular alveolar bone defects by minimally invasive injection. However, the high initial burst release of growth factor and low cell attachment limit the application of microspheres. The modification of microspheres often needs expensive experiments facility or complex chemical reactions, which is difficult to achieve and may bring other problems. In this study, a sol-grade nanoclay, laponite XLS is used to modify the surface of MSs to enhance its affinity to either positively or negatively charged proteins and cells without changing the interior structure of the MSs. Recombinant human bone morphogenetic protein-2 (rhBMP-2) is used as a representation of growth factor to check the osteoinduction ability of laponite XLS-modified MSs. By modification, the protein sustained release, cell loading, and osteoinduction ability of MSs are improved. Modified by 1% laponite XLS, the MSs can not only promote osteogenic differentiation of MC3T3-E1 cells by themselves, but also enhance the effect of the rhBMP-2 below the effective dose. Collectively, the study provides an easy and viable method to modify the biological behavior of microspheres for bone tissue regeneration.

Effect of denture adhesives on masticatory performance: Multicenter randomized controlled trial

PURPOSE

The purpose of this study is to investigate the effects of denture adhesives on masticatory performance via a 10-center, parallel, randomized, controlled trial of complete denture wearers in Japan.

METHODS

The trial was conducted between September 2013 and October 2016. The inclusion criteria were complete edentulism, willingness to undergo new complete denture treatment, and willingness to return for recall treatment. The exclusion criteria were age 90 years or older, presence of severe systemic illness, inability to understand the questionnaires, wearing metal base complete dentures, denture adhesive user, wearing prosthetics for maxillofacial defects, wearing complete dentures with tissue conditioners, and severe xerostomia. Randomization of the powder-type denture adhesive (powder), cream-type denture adhesive (cream), and control (saline) groups was performed using a sealed envelope system. Masticatory performance was measured using color-changeable chewing gum. Intervention blinding was not feasible.

RESULTS

Sixty-seven control, 69 powder, and 64 cream participants are analyzed using the intention-to-treat principle. The participants in all groups show significantly improved masticatory performance at post-intervention (paired t-test with Bonferroni correction P < 0.0001). However, no significant difference in masticatory performance is detected among the three groups (one-way analysis of variance). A significant negative correlation between pre- and post-changes in masticatory performance and intraoral condition scores is observed (Pearson's correlation coefficient, P < 0.0001).

CONCLUSIONS

Although denture adhesives improved the masticatory performance of complete denture wearers, their clinical effects are comparable to those of saline solution. The use of denture adhesives is more effective in complete denture wearers with unsatisfactory intraoral conditions.

Physical Stimulation Methods Developed for In Vitro Neuronal Differentiation Studies of PC12 Cells: A Comprehensive Review

PC12 cells, which are derived from rat adrenal pheochromocytoma cells, are widely used for the study of neuronal differentiation. NGF induces neuronal differentiation in PC12 cells by activating intracellular pathways via the TrkA receptor, which results in elongated neurites and neuron-like characteristics. Moreover, the differentiation requires both the ERK1/2 and p38 MAPK pathways. In addition to NGF, BMPs can also induce neuronal differentiation in PC12 cells. BMPs are part of the TGF-β cytokine superfamily and activate signaling pathways such as p38 MAPK and Smad. However, the brief lifespan of NGF and BMPs may limit their effectiveness in living organisms. Although PC12 cells are used to study the effects of various physical stimuli on neuronal differentiation, the development of new methods and an understanding of the molecular mechanisms are ongoing. In this comprehensive review, we discuss the induction of neuronal differentiation in PC12 cells without relying on NGF, which is already established for electrical, electromagnetic, and thermal stimulation but poses a challenge for mechanical, ultrasound, and light stimulation. Furthermore, the mechanisms underlying neuronal differentiation induced by physical stimuli remain largely unknown. Elucidating these mechanisms holds promise for developing new methods for neural regeneration and advancing neuroregenerative medical technologies using neural stem cells.

GL13K-modified titanium regulates osteogenic differentiation via the NF-κB pathway

The osteoimmune response plays a crucial regulatory role in the osseointegration of dental implants. Previous studies found the antimicrobial peptide coating (GL13K) could activate the immunomodulatory potential of macrophages (Raw 264.7) and promote osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). To further investigate the mechanism of interaction between immunomodulation and differentiation, a co-culture model of the representative cells (Raw 264.7 and BMSCs) was constructed to mimic the immune microenvironment. In this system, GL13K coating of titanium implant effectively inhibited the polarization of the inflammatory M1 type and promoted the polarization of the anti-inflammatory M2 type. Furthermore, the inhibited NF-κB signaling pathway and Mip-2 gene expression were found and validated by bioinformatics analysis and virus-induced gene silencing, which significantly affected the tissue repair process. It can be concluded that the GL13K coating had the potential to establish a localized immune microenvironment conducive to osteogenic differentiation through cellular interactions. Subsequent investigations would be dedicated to a thorough examination of the osseointegration effects of GL13K coating.

Photocatalytic Oxidative Coupling of Methane over Au1 Ag Single-Atom Alloy Modified ZnO with Oxygen and Water Vapor: Synergy of Gold and Silver

C-H dissociation and C-C coupling are two key steps in converting CH4 into multi-carbon compounds. Here we report a synergy of Au and Ag to greatly promote C2 H6 formation over Au1 Ag single-atom alloy nanoparticles (Au1 Ag NPs)-modified ZnO catalyst via photocatalytic oxidative coupling of methane (POCM) with O2 and H2 O. Atomically dispersed Au in Au1 Ag NPs effectively promotes the dissociation of O2 and H2 O into *OOH, promoting C-H activation of CH4 on the photogenerated O- to form *CH3 . Electron-deficient Au single atoms, as hopping ladders, also facilitate the migration of electron donor *CH3 from ZnO to Au1 Ag NPs. Finally, *CH3 coupling can readily occur on Ag atoms of Au1 Ag NPs. An excellent C2 H6 yield of 14.0 mmol g-1  h-1 with a selectivity of 79 % and an apparent quantum yield of 14.6 % at 350 nm is obtained via POCM with O2 and H2 O, which is at least two times that of the photocatalytic system. The bimetallic synergistic strategy offers guidance for future catalyst design for POCM with O2 and H2 O.

Effects of denture adhesives on denture retention and occlusal forces in complete denture wearers: A multicenter, randomized controlled trial

PURPOSE

This study aimed to determine the effects of denture adhesives on denture retention and occlusal force in complete denture wearers in a multicenter, randomized, parallel-group controlled trial.

METHODS

Two hundred edentulous patients wearing complete dentures were allocated to three groups: powder-type denture adhesive, cream-type denture adhesive, and control (saline solution). Denture adhesives and saline solution were applied to the dentures for 4 days. The retentive force of the dentures and occlusal force were measured using a force transducer occlusal force meter at baseline and after 4 days of intervention. In addition to between-group comparisons, subgroup analyses of denture retention and occlusal force were performed based on the level of difficulty of the edentulism treatment. The levels were ranked as I (easy), II, III, and IV (difficult).

RESULTS

Cream-type denture adhesives significantly improved the retentive force of the dentures (P<0.01) and occlusal force (P<0.05), with no significant differences between baseline and post-intervention forces in the powder-type denture adhesive and control groups. In within-group comparisons, cream-type denture adhesives improved both the retentive and occlusal forces at Level II (P<0.05), and powder-type denture adhesives improved the occlusal force at Level II (P<0.01).

CONCLUSIONS

Application of cream-type denture adhesives effectively improves the denture retention and occlusal force in complete denture wearers with a moderate degree of difficulty during edentulism treatment.

β-Tricalcium Phosphate as Alveolar Bone Grafting in Cleft Lip/Palate: A Systematic Review

The aim of this systematic review is to describe and identify the prospects of β-Tricalcium Phosphate (β-TCP) as an alveolar bone grafting (ABG) material in cleft lip/palate (CL/P) or alveolar bone cleft defects. A systematic review protocol based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA 2020) was drafted. The literature search was conducted using MEDLINE/PubMed, Web of Science/ISI Web of Knowledge, Scopus, and the Cochrane Library, with English as the inclusion criterion and no publication year limits. The keywords yielded a total of 5824 publications. After removing duplicates and non-English articles, there were 3196 suitable articles available for evaluation. Subsequently, 1315 studies remained after reviewing titles and abstracts. Furthermore, 85 full articles were assessed for eligibility. After reading the complete texts of those papers, 20 were eventually selected that matched the inclusion requirements. Thirteen out of the twenty studies included in this systematic review were deemed to have a low risk of bias; one had a high risk of bias; and six had a moderate risk of bias due to not reporting randomization. β-TCP, when used as an ABG material, is biocompatible, visible, practical, offers a less invasive procedure, and does not interfere with orthodontic treatment. Synthetic β-TCP for ABG can be an alternative to autologous bone grafts under certain terms and conditions. The efficacy of β-TCP for ABG in CL/P or alveolar bone cleft defects can be enhanced through a tissue engineering approach that combines β-TCP with growth factors, mesenchymal stem cells, or other graft materials, along with modifications to β-TCP's physical properties.

Human umbilical cord mesenchymal stem cells induction in peri-implantitis Rattus norvegicus accelerates and enhances osteogenesis activity and implant osseointegration

Peri-implantitis additional treatment generally aims to repair damaged tissue through a regenerative approach. Human umbilical cord mesenchymal stem cells (hUCMSCs) produce a high osteogenic effect and are capable of modulating the immune system by suppressing inflammatory response, modulating bone resorption, and inducing endogenous osteogenesis.

AIM

This study was intended to discover the effect of hUCMSCs on an implant osseointegration process in peri-implantitis rat subjects as assessed by several markers including interleukin-10 (IL-10), transforming growth factor-β (TGF-β), receptor activator of nuclear factor kappa- β ligand (RANKL), bone morphogenic protein (BMP-2), osterix (Osx), and osteoprotegerin (OPG).

MATERIAL AND METHODS

The research design implemented during this study represented a true experimental design incorporating the use of Rattus norvegicus (Wistar strain) as subjects.

RESULTS

Data analysed by means of a Brown Forsythe test indicated differences between the increase in BMP-2 expression (p < 0.000) and Osx expression (p < 0.001) and between RANKL expression (p < 0.001, Tukey HSD) and OPG expression (p < 0.000, Games Howell).

CONCLUSION

According to the findings of this research, hUCMSCs induction is successful in accelerating and enhancing osteogenic activity and implant osseointegration in peri-implantitis rat subjects.

SP600125 Enhances Temperature-Controlled Repeated Thermal Stimulation-Induced Neurite Outgrowth in PC12-P1F1 Cells

This study evaluated the mechanism of temperature-controlled repeated thermal stimulation (TRTS)-mediated neuronal differentiation. We assessed the effect of SP600125, a c-Jun N-terminal kinase (JNK) inhibitor, on neuronal differentiation of rat PC12-P1F1 cells, which can differentiate into neuron-like cells by exposure to TRTS or neurotrophic factors, including bone morphogenetic protein (BMP) 4. We evaluated neuritogenesis by incubating the cells under conditions of TRTS and/or SP600125. Cotreatment with SP600125 significantly enhanced TRTS-mediated neuritogenesis, whereas that with other selective mitogen-activated protein kinase (MAPK) inhibitors did not-e.g., extracellular signal-regulated kinase (ERK)1/2 inhibitor U0126, and p38 MAPK inhibitor SB203580. We tried to clarify the mechanism of SP600125 action by testing the effect of U0126 and the BMP receptor inhibitor LDN193189 on the SP600125-mediated enhancement of intracellular signaling. SP600125-enhanced TRTS-induced neuritogenesis was significantly inhibited by U0126 or LDN193189. Gene expression analysis revealed that TRTS significantly increased β3-Tubulin, MKK3, and Smad7 gene expressions. Additionally, Smad6 and Smad7 gene expressions were substantially attenuated through SP600125 co-treatment during TRTS. Therefore, SP600125 may partly enhance TRTS-induced neuritogenesis by attenuating the negative feedback loop of BMP signaling. Further investigation of the mechanisms underlying the effect of SP600125 during TRTS-mediated neuritogenesis may contribute to the future development of regenerative neuromedicine.

Mapping of dental graduates' career paths in Hong Kong, Japan and mainland China

Dental graduates have a variety of career-path choices. After graduation, they may join private dental practice, government- or hospital-based dental care services, research groups, academia, business or industry. With globalization and frequent international exchange, dental graduates nowadays can explore careers outside their home country. However, dental education systems and job opportunities vary widely across different regions and countries. Diversity of accreditation in dental education, different licensure requirements, and lack of global competencies in dental care often limit the globalization, operation and survival of dental practice and education worldwide. The requirements for professional education and practice can be quite diverse, and these differences will be barriers to dental graduates seeking career development outside their home home country. Fresh dental graduates have minimal experience in job hunting. More specifically, they are unfamiliar with potential career paths. This paper was based on the 4th trilateral symposium 2022 organized by The University of Hong Kong, Tohoku University, and Fujian Medical University, which offered a lecture to discuss career paths for dental graduates in Hong Kong, Japan, and mainland China. The aim of this paper was to provide dentists, particularly fresh graduated dental students, with practical insight into different career paths in Hong Kong (Special Administrative Region of China, SAR), Japan and mainland China, and factors that may influence their career options. It assists dental students in exploring possibilities in dentistry and preparing for their career development after graduation from dental school.

Evaluation of the ergonomic sitting position adopted by dental students while using dental simulators

Background/purpose

Ergonomics in dentistry encourages the work to be in an organized manner, where a dentist achieves highest performance with maximum comfort and minimum physical and psychological effort. The purpose of this study was to evaluate the ergonomic sitting position of dental students from third, fourth and fifth year undergraduate programs while they prepared teeth 46 and 27 as Black Class I preparation for amalgam using dental simulators.

Materials and methods

Ten students were randomly selected from each year for this study. Photos and videos were taken from them to record their sitting position as they performed a Black Class I amalgam preparation in Nissin simulators.

Results

It was found that more students had a poor ergonomic sitting position while working in mandibular area (60%, torso and neck angle; 53% knee-angle; 50% elbow-angle). When comparing the average score between maxilla and mandible within students of the same year, fourth year students had a significant difference in their average, with a better performance in maxilla (P ≤ 0.01). They also showed better performance in maxillary area compared to fifth-year students (P ≤ 0.008). The main reasons that the students presented as justification for their bad posture were little work time, lack of knowledge, not knowing how to use indirect vision, and poor comfort.

Conclusion

Every undergraduate year had a compromised sitting position, with the exception of fourth-year students when working in maxillary area. No correlation between undergraduate year and performance was found.

Bone Remodeling in Mandible of Wistar Rats with Diabetes Mellitus and Osteoporosis

OBJECTIVES

 This study aimed to determine some of bone molecular expressions and its possible bone remodeling pathway between diabetes mellitus (DM) and osteoporosis model in the mandibular bone of Wistar rats.

MATERIALS AND METHODS

 Twenty-seven female Wistar rats were divided randomly into control and treatment groups. Treatment groups were injected with streptozotocin intraperitoneally to induce DM (P1) and underwent bilateral ovariectomy to generate osteoporosis (P2). All groups were terminated after 12 weeks. Immunohistochemical and hematoxylin-eosin staining were performed to determine the expression of Runt-related transcription factor 2 (RUNX2), Osterix, vascular endothelial growth factor (VEGF), receptor activator of nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), tartrate-resistant acid phosphatase (TRAP), and observed the osteoblast and osteoclast. Statistical analysis was performed using one-way analysis of variance.

RESULTS

 The lowest mean of RUNX2 and VEGF expression was found in the P2 group. The lowest mean of Osterix expression was found in the P1 group. Both P1 and P2 groups of osteoblast/osteoclast ratio were decreased. There were no significant differences in the expression of TRAP between all groups; however, increased expression of RANKL/OPG ratio was only found in the P2 group.

CONCLUSION

 DM and osteoporosis induce changes in the bone remodeling pathway which are represented by a decrease in osteoblast biomarkers and an increase in osteoclast biomarkers.

Differentiation of Bone Mesenchymal Stem Cells Into Vascular Endothelial Cell-Like Cells Using Functionalized Single-Walled Carbon Nanotubes

Carbon nanotubes (CNTs) are a promising bioactive scaffold for bone regeneration because of their superior mechanical and biological properties. Vascularization is crucial in bone tissue engineering, and insufficient vascularization is a long-standing problem in tissue-engineered scaffolds. However, the effect of CNTs on vascularization is still minimal. In the current study, pristine single-walled carbon nanotubes (SWNTs) were purified to prepare different ratios of SWNTs/EDC composites, and their surface morphology and physicochemical properties of SWNTs/EDC were studied. Furthermore, the effect of SWNTs/EDC on vascularization was investigated by inducing the differentiation of bone mesenchymal stem cells (BMSCs) into vascular endothelial cell-like cells (VEC-like cells). Results showed that SWNTs/EDC composite was successfully prepared, and EDC was embedded in the SWNTs matrix and uniformly distributed throughout the composites. The AFM, FTIR spectra, and Raman results confirmed the formation of SWNTs/EDC composites. Besides, the surface topography of the SWNTs/EDC composites presents a rough surface, which may positively affect cell function. In vitro cell culture revealed that SWNTs and SWNTs/EDC composites exhibited excellent biocompatibility and bioactivity. The SWNTs/EDC composite at mass/volume ratios 1:10 had the best enhancement of proliferation and differentiation of BMSCs. Moreover, after culture with SWNTs/EDC composite, approximately 78.3% ± 4.2% of cultured cells are double-positive for FITC-UEA-1 and DiI-Ac-LDL double staining. Additionally, the RNA expression of representative endothelial cell markers VEGF, VEGF-R2, CD31, and vWF in the SWNTs/EDC composite group was significantly higher than those in the control and SWNTs group. With the limitation of our study, the results suggested that SWNTs/EDC composite can promote BMSCs differentiation into VEC-like cells and positively affect angiogenesis and bone regeneration.

Effects of platelet concentrates on implant stability and marginal bone loss: a systematic review and meta-analysis

Background

Osseointegration is essential for the success and stability of implants. Platelet concentrates were reported to enhance osseointegration and improve implant stability. The purpose of this review is to systematically analyze the effects of platelet concentrates on implant stability and marginal bone loss.

Methods

Two researchers independently performed searches in the following databases (last searched on 21 July 2021): MEDLINE (PubMed), Cochrane Library, EMBASE, and Web of Science. In addition, a manual search was carried out on references of relevant reviews and initially included studies. All randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on the application of platelet concentrates in the implant surgery procedure were included. The risk of bias of RCTs and CCTs were assessed with a revised Cochrane risk of bias tool for randomized trials (RoB 2.0) and the risk of bias in non-randomized studies—of interventions (ROBINS-I) tool, respectively. Meta-analyses on implant stability and marginal bone loss were conducted. Researchers used mean difference or standardized mean difference as the effect size and calculated the 95% confidence interval. In addition, subgroup analysis was performed based on the following factors: type of platelet concentrates, method of application, and study design.

Results

Fourteen studies with 284 participants and 588 implants were included in the final analysis. 11 studies reported implant stability and 5 studies reported marginal bone level or marginal bone loss. 3 studies had high risk of bias. The meta-analysis results showed that platelet concentrates can significantly increase implant stability at 1 week (6 studies, 302 implants, MD 4.26, 95% CI 2.03–6.49, P < 0.001) and 4 weeks (8 studies, 373 implants, MD 0.67, 95% CI 0.46–0.88, P < 0.001) after insertion, significantly reduced marginal bone loss at 3 months after insertion (4 studies, 95 implants, mesial: MD − 0.33, 95% CI − 0.46 to − 0.20, P < 0.001; distal: MD − 0.38, 95% CI − 0.54 to − 0.22, P < 0.001). However, the improvement of implant stability at 12 weeks after insertion was limited (P = 0.10). Subgroup analysis showed that PRP did not significantly improve implant stability at 1 week and 4 weeks after insertion (P = 0.38, P = 0.17). Platelet concentrates only placed in the implant sites did not significantly improve implant stability at 1 week after insertion (P = 0.20).

Conclusions

Platelet concentrates can significantly improve implant stability and reduce marginal bone loss in the short term. Large-scale studies with long follow‐up periods are required to explore their long-term effects and compare effects of different types.

Trial registration

This study was registered on PROSPERO, with the Registration Number being CRD42021270214.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-021-01929-x.

Reducing vehicle fuel consumption and exhaust emissions from the application of a green-safety device under real driving

Vehicle emissions have a significantly negative impact on climate change, air quality and human health. Drivers of vehicles are the last major and often overlooked factor that determines vehicle performance. Eco-driving is a relatively low-cost and immediate measure to reduce fuel consumption and emissions significantly. This paper reports investigation of the effects of an on-board green-safety device on fuel consumption and emissions for both experienced and inexperienced drivers. A portable emissions measurement system (PEMS) was installed on a diesel light goods vehicle (LGV) to measure real-driving emissions (RDE), including total hydrocarbons (THC), CO CO₂, NO, NO₂ and particulate matter (PM). In addition, driving parameters (e.g. vehicle speed and acceleration) and environmental parameters (e.g. ambient temperature, humidity and pressure) were recorded in the experiments. The experimental results were evaluated using the Vehicle Specific Power (VSP) methodology to understand the effects of driving behavior on fuel consumption and emissions. The results indicated that driving behavior was improved for both experienced and inexperienced drivers after activation of the on-board green-safety device. In addition, the average time spent was shifted from higher to lower VSP modes by avoiding excessive speed, and aggressive accelerations and decelerations. For experienced drivers, the average fuel consumption and NO, NO₂ and soot emissions were reduced by 5%, 56%, 39% and 35%, respectively, with the on-board green-safety device. For inexperienced drivers, the average reductions were 6%, 65%, 50% and 19%, respectively. Moreover, the long-term formed habits of experienced drivers are harder to be changed to accept the assistance of the green-safety device, whereas inexperienced drivers are likely to be more receptive to change and improve their driving behaviors.

Surface Modifications for Zirconia Dental Implants: A Review

Zirconia-based bioceramic is a potential material for dental implants developed and introduced in dentistry 30 years ago. However, some limitations still exist for zirconia implants caused by several factors, such as manufacturing difficulties, low-temperature degradation (LTD), long-term stability, and clinical experience. Several studies validated that some subtle changes on the zirconia surface might significantly impact its mechanical properties and osseointegration. Thus, attention was paid to the effect of surface modification of zirconia implants. This review generally summarizes the surface modifications of zirconia implants to date classified as physical treatment, chemical treatment, and surface coating, aiming to give an overall perspective based on the current situation. In conclusion, surface modification is an effective and essential method for zirconia implant application. However, before clinical use, we need more knowledge about these modification methods.

Effect of online learning for dental education in asia during the pandemic of COVID-19

BACKGROUND/PURPOSE

Online learning has been utilized in the world to continue educational activities in dentistry, which was severely affected by the pandemic of coronavirus disease 2019 (COVID-19). The purpose of this study was aimed to evaluate the effect of online learning during the pandemic of COVID-19 in different dental schools of different countries in Asia by the questionnaire survey.

MATERIALS AND METHODS

Mantel-Haenszel chi-square tests were used to analyze the difference between dental schools with and without shutdown. A questionnaire-based online survey was used to evaluate the online learning effect on undergraduate students in 13 dental schools of 7 Asia countries and regions.

RESULTS

For the question that blended learning class has better learning efficiency, the agreement rate was significantly higher in the students (80.3%) from the dental schools that did not suspend face-to-face education activities than in the students (50.3%) from the dental school that was shut down.

CONCLUSION

Within the limitation of this study, it is concluded that a combination of physical and online classes in terms of blended learning courses will be the future trend for dental education.

Multivariate analysis reveals oral health-related quality of life of complete denture wearers with denture adhesives: a multicenter randomized controlled trial

Purpose To investigate the difference in improvement of oral health-related quality of life (OHR-QoL) depending on the oral and denture conditions of a complete denture wearer when using a cream or powder type denture adhesive in a 10-center parallel randomized clinical trial.Methods Two hundred edentulous subjects who wore complete dentures were allocated to each of the three groups according to denture adhesive type: cream, powder, and control (saline solution). The materials were applied to the mucosal surface of the dentures for 4 days, and baseline data and data after the intervention were collected. OHR-QoL was assessed using the Japanese version of the modified Oral Health Impact Profile for Edentulous Patients (OHIP-EDENT-J) scale for outcome. Multivariate analysis was used to investigate improvements in OHR-QoL according to participant characteristics among complete denture wearers using these materials.Results OHIP-EDENT-J scores were significantly decreased in all groups after the intervention (p < 0.05); however, there were no statistically significant differences among the groups. Multiple logistic regression analysis revealed a significant association between the vertical height of the maxillary and mandibular alveolar ridge and OHIP-EDENT-J scores in the cream-type denture adhesive group. In contrast, there were no significant association between participant characteristics and OHIP-EDENT-J scores in the powder-type adhesive and control groups.Conclusions The use of denture adhesives could improve OHR-QoL for complete denture wearers. The cream-type denture adhesives may be expected to improve OHR-QoL in patients with poor residual ridge conditions compared with patients with good residual ridge conditions.

Artificial Intelligence in Biomedical Applications of Zirconia

Artificial intelligence (AI) is rapidly developed based on computer technology, which can perform tasks that customarily require human intelligence by building intelligent software or machines. As a subfield of AI, machine learning (ML) can learn from the intrinsic statistical patterns and structures in data through algorithms to predict invisible data. With the increasing interest in aesthetics in dentistry, zirconia has drawn lots of attention due to its superior biocompatibility, aesthetically pleasing, high corrosion resistance, good mechanical properties, and absence of reported allergic reactions. The evolution of AI and ML led to the development of novel approaches for the biomedical applications of zirconia in dental devices. AI techniques in zirconia-related research and clinical applications have attracted much attention due to their ability to analyze data and reveal correlations between complex phenomena. The AI applications in the field of zirconia science change according to the application direction of zirconia. Therefore, in this article, we focused on AI in biomedical applications of zirconia in dental devices and AI in zirconia-related applications in dentistry.

Effect of Different Retightening Procedures on Screw Stability in External-hex and Internal Tri-channel Connections: An In Vitro Study

PURPOSE

To evaluate the effect of different procedures for retightening the abutment screw on the screw stability between the abutment and implant.

MATERIALS AND METHODS

External hexagon connection (EHC) and internal tri-channel connection (ITC) implants were employed in this study. Each abutment screw was used for the following applications (n = 5 for each group): group 0 = abutment was tightened and retightened with a 10-minute interval; group 1 = abutment was tightened and retightened with a 10-minute interval, then loaded for 500,000 cycles; group 2 = abutment was loaded for 83,000 cycles during tightening and retightening and then loaded for 500,000 cycles; group 3 = abutment was loaded for 167,000 cycles during tightening and retightening and then loaded for 500,000 cycles; and group 4 = abutment was loaded for 250,000 cycles during tightening and retightening and then loaded for 500,000 cycles. Both tightening and retightening torques were set at 35 Ncm, and dynamic oblique loading between 0 N and 200 N was applied on the abutment in all groups. The settlement of the abutments (settling value) after retightening and the abutments' removal torque values (RTVs) after testing were measured.

RESULTS

No significant differences in settling values were found for EHC or ITC. There were significant differences in the RTVs on EHC implants, but ITC implants showed no difference in RTV with different prosthetic retightening applications.

CONCLUSION

The retightening application affected the joint stability of EHC implants, but did not affect the settlement or joint stability of ITC implants.

Applications of Hydrogel with Special Physical Properties in Bone and Cartilage Regeneration

Hydrogel is a polymer matrix containing a large amount of water. It is similar to extracellular matrix components. It comes into contact with blood, body fluids, and human tissues without affecting the metabolism of organisms. It can be applied to bone and cartilage tissues. This article introduces the high-strength polymer hydrogel and its modification methods to adapt to the field of bone and cartilage tissue engineering. From the perspective of the mechanical properties of hydrogels, the mechanical strength of hydrogels has experienced from the weak-strength traditional hydrogels to the high-strength hydrogels, then the injectable hydrogels were invented and realized the purpose of good fluidity before the use of hydrogels and high strength in the later period. In addition, specific methods to give special physical properties to the hydrogel used in the field of bone and cartilage tissue engineering will also be discussed, such as 3D printing, integrated repair of bone and cartilage tissue, bone vascularization, and osteogenesis hydrogels that regulate cell growth, antibacterial properties, and repeatable viscosity in humid environments. Finally, we explain the main reasons and contradictions in current applications, look forward to the research prospects in the field of bone and cartilage tissue engineering, and emphasize the importance of conducting research in this field to promote medical progress.

Innovation of dental education during COVID-19 pandemic

BACKGROUND/PURPOSE

The impact of the pandemic of COVID-19 has a certain influence on various walks of life around the world. Because of the pandemic of this novel coronavirus in terms of COVID-19, the social life global wide has been changed a lot. To keep the social distance between human being to prevent from being infected is the most important strategy for all the countries. Many dental schools have been locked down to minimize the spread out of this coronavirus infection. Close contact between human being are required for all those learning process in traditional dental education. Learning methods should be innovated to keep on the learning process but away from being infected for dental education during pandemic. The purpose of this manuscript is to exchange the information and experience of those dental educators from different countries to prepare for the future demand for dental education during pandemic.

MATERIALS AND METHODS

By means of three online symposiums, dental educators from different countries were invited to give presentation and discussion regarding to the information and experience in the innovation of dental education during the pandemic.

RESULTS

The results showed that the impact of the pandemic of COVID-19 affects the dental education a lot. Intelligent technology has certain benefit for the learning process of dental education during the pandemic.

CONCLUSION

The impact of the pandemic of COVID-19 affects dental education a lot. The model of dental education should be innovated to suit different situations and novelty intelligent technology should be applied for future dental education.

Potential of pure cellulose nanofibers as a denture base material

A study was conducted to evaluate the basic mechanical properties of a pure cellulose nanofiber (CNF) material in comparison with a commercial denture base material (polymethylmethacrylate [PMMA] acrylic resin). The working hypothesis was that CNFs have potential for use as denture base materials. Pure CNF specimens fabricated under various conditions were examined. The flexural strength (FS) and flexural modulus (FM) of the specimens were measured using the three-point bending test, and the morphologies of the fractured surfaces were examined using scanning electron microscopy. Addition of tricalcium phosphate to dehydrate the CNFs did not improve their FS or FM. Conversely, substitution with methanol effectively improved the dehydration process and significantly affected the mechanical properties of the CNFs. As the degree of CNF defibration increased, the physical properties of the specimens improved significantly. However, addition of CNFs to PMMA liquid to create CNF-reinforced PMMA did not improve the mechanical properties. Pure CNF specimens fabricated under particular conditions had higher FS and FM values than the control, suggesting that CNFs have potential as a "petroleum-free" alternative to acrylic resin denture base materials. Pure CNF would be potentially useful as a denture base material, and presumably applicable to computer-aided design/manufacture (CAD/CAM).

Guidelines for innovation in dental education during the coronavirus disease 2019 pandemic

During the current coronavirus disease 2019 (COVID-19) pandemic, dental education and training requiring face-to-face interaction must prioritize infection prevention and the safety of students, staff, and patients. In July 2020, the Association for Dental Education, Asia Pacific (ADEAP) published safety guidelines for safe dental education during the COVID-19 pandemic. These guidelines summarize ADEAP recommendations for classroom-based courses, reopening of simulated training courses and dental clinics, and provision of clinical skills training courses in dentistry during the COIVID-19 pandemic. They have been formulated to ensure the safety of students and teaching staff, dental auxiliary staff, and patients. However, the present guidelines are considered appropriate only when the number of COVID-19 epidemic cases has been significantly reduced, i.e. when the epidemiological curve has flattened in the area concerned. The criteria for lifting restrictions on activities should be consistent with relevant jurisdictional guidelines.

Characterization of PC12 Cell Subclones with Different Sensitivities to Programmed Thermal Stimulation

Neuritogenesis is the process underling nervous system regeneration; however, optimal extracellular signals that can promote neuronal regenerative activities require further investigation. Previously, we developed a novel method for inducing neuronal differentiation in rat PC12 cells using temperature-controlled repeated thermal stimulation (TRTS) with a heating plate. Based on neurogenic sensitivity to TRTS, PC12 cells were classified as either hyper- or hyposensitive. In this study, we aimed to investigate the mechanism of hyposensitivity by establishing two PC12-derived subclones according to TRTS sensitivity during differentiation: PC12-P1F1, a hypersensitive subclone, and PC12-P1D10, a hyposensitive subclone. To characterize these subclones, cell size and neuritogenesis were evaluated in subclones treated with nerve growth factor (NGF), bone morphogenetic protein (BMP), or various TRTS. No significant differences in cell size were observed among the parental cells and subclones. BMP4- or TRTS-induced neuritogenesis was increased in PC12-P1F1 cells compared to that in the parental cells, while no neuritogenesis was observed in PC12-P1D10 cells. In contrast, NGF-induced neuritogenesis was observed in all three cell lines. Furthermore, a BMP inhibitor, LDN-193189, considerably inhibited TRTS-induced neuritogenesis. These results suggest that the BMP pathway might be required for TRTS-induced neuritogenesis, demonstrating the useful aspects of these novel subclones for TRTS research.

Effect of amylase activity on mechanical properties of dental composite resin

The purpose of this study was to investigate the effect of amylase activity on the mechanical properties of three dental composite resin (Filtek Z350; Filtek Z250 and Polofil Supra). The specimens were immersed in amylase solution at four different activities (25, 50, 100 and 200 KIU/L) with an artificial saliva solution (AS) as a control. The flexural strength (FS) and elastic modulus (EM) were determined in a three-point bending test after immersion for periods up to 12 months. In addition, surface roughness and surface morphology also determined. The FS of Filtek Z350 reaching the lowest level of 67.86 MPa after AS immersion for one year. There was a general trend for FS to decrease following immersion in AS for all the tested materials. However, the amylase groups did not undergo a significant decrease in FS and EM, and there was a slight increase in FS and EM for Polofil Supra.

Human Umbilical Cord Mesenchymal Stem Cell-induced Osterix, Bone Morphogenetic Protein-2, and Tartrate-resistant Acid Phosphatase Expression in Osteoporotic Mandibular Bone

OBJECTIVES

 The aim of this study was to prove that human umbilical cord mesenchymal stem cell (hUCMSC) therapy conducted according to the mandibular osteoporotic model will increase Osterix (Osx) and bone morphogenetic protein-2 (BMP-2) expression, while reducing tartrate-resistant acid phosphatase (TRAP) expression. PKH26 labeling proves that mandibular bone regeneration is produced by hUCMSCs induction.

MATERIALS AND METHODS

 This study incorporated a true posttest only control group design. Twenty-five female Wistar rats were randomly divided into five groups consisting of the sham surgery (N) group, osteoporotic groups injected with gelatin for 4 weeks (G4) and 8 weeks (G8), and osteoporotic groups injected with hUCMSC-gelatin for 4weeks (SC4) and 8 weeks (SC8). All subjects were provided for BMP-2, Osx, and TRAP on immunohistochemistry examination and PKH-26 labeling.

STATISTICAL ANALYSIS

 All data were analyzed using ANOVA and Tukey HSD tests with p < 0.05 being considered as statistically significant.

RESULTS

 Compared with other groups, the highest level of BMP-2 and Osx occurred in the sham surgery (N) and osteoporotic groups injected with hUCMSCs-gelatin (SC), while the lowest level of TRAP was found in SC4. During 4- and 8-week observation periods, the PKH 26 appeared green (fluorescent).

CONCLUSIONS

 hUCMSC demonstrates high-osteogenic activity and increased osteoporotic mandibular bone regeneration, as shown by increased expression of Osx and BMP-2 and decreased TRAP expression. From the labeling, PKH-26 proved that viable hUCMSCs in gelatin solvent can be present in the mandibular bone and be capable of promoting osteogenic differentiation and increasing mineralization and bone formation in the osteoporotic mandibular bone.

The Effects of Syndecan on Osteoblastic Cell Adhesion Onto Nano-Zirconia Surface

Purpose

Zirconia is one of the most promising implant materials due to its favorable physical, mechanical and biological properties. However, until now, we know little about the mechanism of osseointegration on zirconia. The purpose of this study is to evaluate the effect of Syndecan (Sdc) on osteoblastic cell (MC3T3-E1) adhesion and proliferation onto zirconia materials.

Materials and Methods

The mirror-polished disks 15 mm in diameter and 1.5 mm in thick of commercial pure titanium (CpTi), 3mol% yttria-stabilized tetragonal zirconia polycrystalline (3Y-TZP) and nano-zirconia (NanoZr) are used in this study. MC3T3-E1 cells were seeded onto specimen surfaces and subjected to RNA interference (RNAi) for Syndecan-1, Syndecan-2, Syndecan-3, and Syndecan-4. At 48h post-transfection, the cell morphology, actin cytoskeleton, and focal adhesion were observed using scanning electron microscopy or laser scanning confocal fluorescence microscopy. At 24h and 48h post-transfection, cell counting kit-8 (CCK-8) assay was used to investigate cell proliferation.

Results

The cell morphology of MC3T3-E1 cells on CpTi, 3Y-TZP, and NanoZr changed into abnormal shape after gene silencing of Syndecan. Among the Syndecan family, Sdc-2 is responsible for NanoZr-specific morphology regulation, via maintenance of cytoskeletal conformation without affecting cellular attachment. According to CCK-8 assay, Sdc-2 affects the osteoblastic cell proliferation onto NanoZr.

Conclusion

Within the limitation of this study, we suggest that Syndecan affects osteoblastic cell adhesion on CpTi, 3Y-TZP, and NanoZr. Sdc-2 might be an important heparin-sensitive cell membrane regulator in osteoblastic cell adhesion, specifically on NanoZr, through the organization of actin cytoskeleton and affects osteoblastic cell proliferation.

Antifungal effect of tea extracts on Candida albicans

Determining whether tea extracts are effective in removing Candida albicans (C. albicans) from dentures is of interest. This study aimed to investigate the antifungal effect of tea extracts on C. albicans. One green tea (Anji white tea, AGW) and 2 oolong teas (Tie Guan Yin, TGY; Da Hong Pao, DHP) of different concentrations were tested. C. albicans suspensions were inoculated on the plates and the numbers of colony-forming units (CFU) in the culture medium were used to screen for the optimum tea extracts. Polymethyl methacrylate (PMMA) specimens that contained C. albicans biofilms were then treated with the tea extracts and the numbers of CFU were counted. The antifungal activities of the tea extracts were not significantly correlated with their catechin concentrations. Although AGW at 10.0 mg/mL and DHP at 2.5 mg/mL significantly inhibited C. albicans in the culture medium, the extracts failed to exert inhibitory effects against C. albicans biofilms on the PMMA surfaces.

Effects of adjunctive probiotic L. reuteri lozenges on S/RSD outcomes at molar sites with deep pockets

AIM

To evaluate effects of probiotic Lactobacillus reuteri (L. reuteri) lozenges as an S/RSD adjunct on site-level changes at molars with deep pockets.

MATERIALS AND METHODS

447 molar sites with pockets ≥ 5 mm from a previous randomized clinical trial of adjunctive L. reuteri lozenges for 28 days were analyzed. Multilevel mixed-effect models (MLM) were constructed to analyze site-level outcomes "change in CAL" and "pocket closure" (residual PPD < 5 mm) in placebo and probiotic groups at 90 and 180 days. Possible patient-, tooth-, and site-level predictors were analyzed as fixed-effects.

RESULTS

Estimated change in CAL in probiotic (90 day: 0.87 mm, 180 day: 0.68 mm) was greater than placebo treated molar sites (90 day: 0.73 mm, 180 day: 0.66 mm) and the relative risk (RR) of pocket closure in the probiotic group (90 day: 1.7, 180 day: 1.6) was higher as compared to placebo. Furcation involvement and BOP at site predicted significantly worse treatment outcomes.

CONCLUSION

As compared to S/RSD with placebo, a 28-day course of adjunctive probiotic L. reuteri lozenges improved CAL change at molar sites with ≥ 5 mm deep pockets and conferred a higher probability of shallow residual pocket depth. Presence of furcation-involvement and bleeding on probing worsened treatment outcomes.

Minimally invasive procedures for deficient interdental papillae: A review

OBJECTIVE

Deficient interdental papillae cause a series of problems, including food impaction, phonetic difficulties, and esthetic concerns. The purpose of this article is to provide valid clinical recommendations for clinicians to address these problems in a predictable and less invasive way.

OVERVIEW

Numerous treatments are available for interdental papillae reconstruction, but most of them involve surgery and yield unpredictable outcomes. Minimally invasive treatments have the advantages of being effective, predictable, and involving only slight injury as compared to surgical treatments. We included 66 studies obtained after searching for relevant papers in PubMed and Web of Science. The etiology and classification of deficient interdental papillae are explained and minimally invasive procedures for deficient interdental papillae reconstruction are summarized.

CONCLUSIONS

Minimally invasive procedures are promising ways to reconstruct deficient interdental papillae, and have the advantages of slight pain and rapid recovery. It should be noticed that some of the minimally invasive treatments still require further long-term observation to confirm their efficacy.

CLINICAL SIGNIFICANCE

Familiarity with etiology and classification of deficient interdental papillae can help clinicians to choose the appropriate minimally invasive approach as well as help with case collection to enhance esthetics status in patients with deficient interdental papillae.

Effects of low-temperature degradation on the surface roughness of yttria-stabilized tetragonal zirconia polycrystal ceramics: A systematic review and meta-analysis

STATEMENT OF PROBLEM

A wide range of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics have been applied for dental restorations. However, whether hydrothermal aging affects the surface roughness of Y-TZP is unknown.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the effects of low-temperature degradation (LTD) on the surface roughness of Y-TZP ceramics.

MATERIAL AND METHODS

This report follows the Preferred Reporting Items for Systematic Reviews and Qualitative Analyses statement. The literature search was conducted with Medline through the PubMed, Web of Science, and Cochrane Library with no publication year limits. The screening and quality assessment were performed by 2 independent reviewers. The studies comparing the surface roughness of Y-TZP ceramics after LTD by using steam autoclave aging were included in the meta-analysis. Meta-analyses were conducted with a random-effects model (α=.05) by using Review Manager Software (Cochrane Collaboration).

RESULTS

Of the 203 potentially relevant studies, 32 full texts were assessed for eligibility. A total of 17 articles were included in the systematic review, and 15 were included in the qualitative analyses. The results showed no significant difference in the arithmetic average height (R_a) values between the nonaged and aged Y-TZP (P=.670; mean difference=0.01; 95% confidence interval=-0.03 to 0.05). Subgroup analyses revealed that the aging duration (P=.003) and specimen preparation (P=.010) contributed significantly to the changes in the surface roughness of the Y-TZP ceramics.

CONCLUSIONS

Although LTD was found to have no significant effects on the surface roughness of Y-TZP ceramics, the effects of LTD depended on the duration of the steam autoclave process and the specimen preparation.

Salidroside Reduces Inflammation and Brain Injury After Permanent Middle Cerebral Artery Occlusion in Rats by Regulating PI3K/PKB/Nrf2/NFκB Signaling Rather than Complement C3 Activity

Salidroside, an active constituent of Rhodiola rosea, is neuroprotective after transient middle cerebral artery occlusion (tMCAO). However, its effects in other experimental stroke models are less understood. Here, we investigated the effect of daily intraperitoneal injections of salidroside in rats after permanent MCAO (pMCAO). Cerebral infarct volumes at 1 day after pMCAO were significantly reduced by treatment with 100 mg/kg/day salidroside, but not by 25 or 50 mg/kg/day, and this benefit of salidroside increased significantly over at least 7 days of treatment, when it was also accompanied by decreased neurological deficit scores. These observations led us to investigate the underlying mechanism of action of salidroside. 100 mg/kg salidroside for 1 day increased NeuN, Nrf2, and its downstream mediator HO-1, while it reduced nuclear NFκB p50, IL-6, and TNFα. Brusatol, a Nrf2 inhibitor, blocked the actions of salidroside on Nrf2, NFκB p50, IL-6, and TNFα. Salidroside also increased the ratio of p-PKB/PKB at 1 day after pMCAO even in the presence of brusatol. LY294002, a PI3K inhibitor, prevented all these effects of salidroside, including those on NeuN, p-PKB/PKB, Nrf2, HO-1, and pro-inflammatory mediators. In contrast, salidroside had no significant effect on the level of cerebral complement C3 after pMCAO, or on the activity of C3 as measured by the expression of cerebral Egr1. Our findings therefore suggest that salidroside reduces neuroinflammation and neural damage by regulating the PI3K/PKB/Nrf2/NFκB signaling pathway after pMCAO, and that this neuroprotective effect does not involve modulation of complement C3 activity.

Evaluation of silk fibroin electrogel coating for zirconia material surface

Zirconia is commonly used in dental applications. It has been reported that surface-modified zirconia implants showed better performance in vivo than machined zirconia implants. Silk fibroin electrogel is a good candidate for controlled drug delivery; however, the use of silk fibroin electrogel on zirconia implants has not previously been reported. The aim of this study was to investigate a method to coat zirconia implants with silk fibroin electrogel and evaluate the mechanical and biological properties of the coating. The results show that the wettability of the coating was close to that of sand-blasted and acid-etched (SLA)-treated zirconia, and the bond strength was larger than that of the coating prepared from silk fibroin aqueous solution. ATR-FTIR spectra provided evidence that the secondary structure changed during the electrogelation process. Culturing cells on the coating revealed its nontoxicity to osteoblast-like cells. Thus, it can be suggested that a silk fibroin electrogel coating is a promising biocompatible and degradable drugdelivery material for zirconia implants.

A remote sensing emissions monitoring programme reduces emissions of gasoline and LPG vehicles

Vehicle emissions are a major source of air pollution in Hong Kong affecting human health. A 'strengthened emissions control of gasoline and liquefied petroleum gas (LPG) vehicles' programme has been operating in Hong Kong since September 2014 utilising remote sensing (RS) technology. RS has provided measurement data to successfully identify high emitting gasoline and LPG vehicles which then need to be repaired or removed from the on-road vehicle fleet. This paper aims to evaluate the effectiveness of this globally unique RS monitoring programme. A large RS dataset of 2,144,422 records was obtained covering the period from 6th January 2012 to 30th December 2016, of which 1,206,762 records were valid and suitable for further investigation. The results show that there have been significant reductions of emissions factors (EF) for 40.5% HC, 45.3% CO and 29.6% NO for gasoline vehicles. Additionally, EF reductions of 48.4% HC, 41.1% CO and 58.7% NO were achieved for LPG vehicles. For the combined vehicle fleet, the reductions for HC, CO and NO were 55.9%, 50.5% and 60.9% respectively during this survey period. The findings demonstrate that the strengthened emissions control programme utilising RS has been very effective in identifying high emitting vehicles for repair so as to reduce the emissions from gasoline and LPG vehicles under real driving.

Review of Polygonatum sibiricum: A new natural cosmetic ingredient

With the developments of science and technology, social development and people's pursuit of quality life, natural and safe skin care products occupied half of the cosmetics industry. In recent years, as synthetic drugs were found that which had toxic and some side effects, people have a tendency to return to nature. Thus, traditional Chinese medicinal plants were applied to natural cosmetics with good efficacy, little side effects and no allergy which had more advantages than synthetic products. The cosmetic products with pure natural ingredients were more and more favored by consumers. Therefore, the article mainly pays attention to the relationship between the active ingredients of Polygonatum sibiricum (PS) and their cosmetic effects, mainly included anti-aging activity, anti-bacteria effect, skin whitening and moisturizing effects. The article will provide more possibilities for research of natural ingredients cosmetics.

Association between Beta3-Adrenergic Receptor Trp64Arg Polymorphism and Fat Preference in Healthy Young Japanese Women

Beta3-adrenergic receptor (ADRB3) is a mediator of catecholamine-stimulated lipolysis in humans. The Trp64Arg polymorphism with T/C transition in the ADRB3 gene has been considered to reduce lipolysis and metabolic expenditure. Here, we investigated the hitherto unknown role of the Trp64Arg substitution on food preference among healthy young adults (mean age, 24.3; n = 53, including 25 men). Preference toward four food types (bitter, sour, salty, or sweet) and greasy (high-fat) foods was examined using a self-reported questionnaire. There was no noticeable sex-difference in food preference. Incidentally, only among female subjects, the genotype frequencies of the Trp64Arg polymorphism were in accordance with the Hardy-Weinberg equilibrium. Consequently, female subjects were divided into two groups for further analyses: 18 subjects with TT genotype (Trp64Trp) (wild-type group) and 10 subjects with TC genotype (Trp64Arg) (heterozygous group). No significant difference was observed in preference for four food types between the groups. However, when sweet foods were divided into high-fat and low-fat subgroups, food preference for high-fat sweet foods in heterozygous group was significantly higher than that in wild-type group. Moreover, when subjects were divided into two classes based on preference for greasy foods (like, n = 16 or dislike, n = 12), the preference degree in heterozygous group who liked high-fat foods (n = 5) was significantly higher than that in wild-type group (n = 11), suggesting that the Trp64Arg substitution might genetically enhance high-fat food preference. Thus, understanding the relationship between ADRB3 Trp64Arg substitution and fat preference will be valuable for obesity prevention.

Subjective Evaluation of Denture Adhesives: A Multicenter Randomized Controlled Trial

INTRODUCTION

Many reports show that denture adhesives improve the retention and stability of dentures. However, few randomized controlled trials have examined the effects of denture adhesives.

OBJECTIVE

This 10-center randomized controlled trial with parallel groups involving 200 edentulous patients wearing complete dentures aimed to evaluate the effects of short-term use of cream and powder denture adhesives.

METHODS

Patients were allocated into 2 cream- and powder-type adhesive groups and 1 control group. Intervention groups were treated with the 2 adhesives (1 each), and the control group received saline solution. Adhesive or control was applied to the denture-mucosal surface for 4 d, and data at baseline and after day 4 of intervention (i.e., 8 meals) were obtained. Patient satisfaction was evaluated with a 100-mm visual analog scale. Oral health-related quality of life was measured with the Japanese version of the Oral Health Impact Profile for Edentulous Patients. Perceived chewing ability was evaluated by a questionnaire regarding ease of chewing and swallowing food. Between-group comparisons were performed with Kruskal-Wallis tests with the Mann-Whitney U test adjusted by Bonferroni correction. Within-group comparisons of pre- and postintervention measurements were performed with the Wilcoxon signed-rank test. Intention-to-treat analysis was also performed.

RESULTS

Between-group comparisons showed no significant differences for general satisfaction or Oral Health Impact Profile for Edentulous Patients. However, significant differences in satisfaction with various denture functions with cream- and powder-type adhesives were seen in pre- and postintervention comparisons (P < 0.05). Significant differences were also observed for perceived chewing ability of hard foods (P < 0.05).

CONCLUSION

These results suggest that although denture adhesives do not invariably improve denture function, they do affect subjective evaluations and possibly chewing of hard foods. Therefore, the effects of denture adhesive use are insufficient to resolve any fundamental dissatisfaction with dentures ( ClinicalTrials.gov NCT01712802 ).

KNOWLEDGE TRANSFER STATEMENT

The results of this study suggest that denture adhesives should be applied under certain conditions; however, an appropriate diagnosis is important before application. These practice-based data provide information to establish evidence-based guidelines for applying denture adhesives.

Initial osteoblast adhesion and subsequent differentiation on zirconia surfaces are regulated by integrins and heparin-sensitive molecule

Purpose

It is well known that zirconia materials have good biocompatibility; however, little is known regarding the mechanism by which cells attach to these materials. The purpose of this study is to elucidate the mechanism of cell attachment.

Materials and methods

In this study, we examined the surface characteristics of ceria-stabilized zirconia/alumina nanocomposite (NANOZR), yttria-stabilized zirconia (Y-TZP) and commercially pure titanium (CpTi), and we evaluated the initial response of osteoblast-like cells to them with different inhibitors.

Results

Under the same polishing treatment, the three materials, NANOZR, Y-TZP and CpTi, show similar surface wettability but different surface roughness. Osteoblasts could adhere to the surface of all three materials, and spindle shapes were clearer in serum-containing media compared to PBS and serum-free culture media, suggesting that serum-contained proteins are helpful for the initial cell adhesion and spreading. Cell adhesion and proliferation were disrupted in the presence of EDTA. RGD-peptide interfered with cell proliferation by affecting cell protrusion and stress fibers. Monoclonal antibody against non-RGD type integrin α₂β₁ enhanced proliferation in Y-TZP, CpTi and culture dish but not in NANOZR. Cell proliferation on NANOZR was specifically inhibited in the presence of heparin. Furthermore, under heparin administration, spindle shape formation was maintained but actin cytoskeleton was disrupted, resulting in loose cellular spreading.

Conclusion

These results suggest that RGD type integrins and heparin-sensitive protein in coordination regulate cell morphology and proliferation on NANOZR, through the regulation of cell polarity and stress fiber formation, respectively.

Tackling nitric oxide emissions from dominant diesel vehicle models using on-road remote sensing technology

Remote sensing provides a rapid detection of vehicle emissions under real driving condition. Remote sensing studies showed that diesel nitrogen oxides emissions changed little or were even increasing in recent years despite the tightened emission standards. To more accurately and fairly evaluate the emission trends, it is hypothesized that analysis should be detailed for individual vehicle models as each model adopted different emissions control technologies and retrofitted the engine/vehicle at different time. Therefore, this study was aimed to investigate the recent nitric oxide (NO) emission trends of the dominant diesel vehicle models using a large remote sensing dataset collected in Hong Kong. The results showed that the diesel vehicle fleet was dominated by only seven models, accounting for 78% of the total remote sensing records. Although each model had different emission levels and trends, generally all the dominant models showed a steady decrease or stable level in the fuel based NO emission factors (g/kg fuel) over the period studied except for BaM1 and BdM2. A significant increase was observed for the BaM1 2.49 L and early 2.98 L models during 2005-2011, which we attribute to the change in the diesel fuel injection technology. However, the overall mean NO emission factor of all the vehicles was stable during 1991-2006 and then decreased steadily during 2006-2016, in which the emission trends of individual models were averaged out and thus masked. Nevertheless, the latest small, medium and heavy diesel vehicles achieved similar NO emission factors due to the converging of operation windows of the engine and emission control devices. The findings suggested that the increasingly stringent European emission standards were not very effective in reducing the NO emissions of some diesel vehicle models in the real world.

Loading icariin on titanium surfaces by phase-transited lysozyme priming and layer-by-layer self-assembly of hyaluronic acid/chitosan to improve surface osteogenesis ability

Purpose

Icariin (ICA) is one of the main active constituents of Herba Epimedii for improving osteogenesis. It is necessary to create a simple and efficient method to load ICA onto the surface of titanium (Ti) implant. The purpose of this study was to establish a local ICA delivery system via a layer-by-layer (LbL) self-assembly system on phase-transited lysozyme (PTL)-primed Ti surface.

Materials and methods

A PTL nanofilm was first firmly coated on the pristine Ti. Then, the ICA-loaded hyaluronic acid/chitosan (HA/CS) multilayer was applied via the LbL system to form the HA/CS-ICA surface. This established HA/CS-ICA surface was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The ICA release pattern of the HA/CS-ICA surface was also examined. MC3T3-E1 osteoblast culture test and a rat model were used to evaluate the effects of the HA/CS-ICA surface in vitro and in vivo.

Results

SEM, XPS and contact angle measurement demonstrated successful fabrication of the HA/CS-ICA surface. The HA/CS-ICA surfaces with different ICA concentrations revealed a controlled release profile of ICA during a 2-week monitoring span. Osteoblasts grown on the coated substrates displayed higher adhesion, viability, proliferation and ALP activity than those on the polished Ti surface. Furthermore, in vivo histological evaluation revealed much obvious bone formation in the ICA-coated group by histological staining and double fluorescent labeling at 2 weeks after implantation.

Conclusion

The present study demonstrated that ICA-immobilized HA/CS multilayer on the PTL-primed Ti surface had a sustained release pattern of ICA which could promote the osteogenesis of osteoblasts in vitro and improve early osseointegration in vivo. This study provides a novel method for creating a sustained ICA delivery system to improve osteoblast response and osseointegration.