Effects of cryopreservation on the biomechanical properties of dentin in cryopreserved teeth: An in-vitro study.

This study focused on the biomechanical properties and microstructural changes in dentin of teeth in different age groups after cryopreserved for different durations. Ninety third molars from three age groups (youth group, middle-age group, and elderly group), were collected and randomly divided into three groups according to freezing time at -196 °C (7 days, 30 days, and 90 days). Control group was shored at ordinary temperature. After rewarming, the compressive strength and elastic modulus of the dentin were measured with an electronic universal tester. Scanning electron microscopy was used to evaluate the microstructure of dentin after cryopreservation. After cryopreservation, the compressive strength of the teeth in each experimental group was not significantly different from control group. With the increase of freezing time and age, dentin's elastic modulus showed a decreasing trend. There were statistically significances between the control group and freezing 90d group, freezing 7d and 90d group, youth and middle-aged group, youth and elderly group (P < 0.05). Both freezing time and age factors were significant for the elastic modulus of dentin(P＜0.05). There was no interaction effect for age and freezing time. In transverse sections of scanning electron microscopy, the dentinal tubule became narrower, partially occluded, and more easily adhered to impurities in the long freezing time and elderly group. In longitudinal sections, with freezing time and age, the inner wall of the dentinal tubules became rough especially in the aged group cryopreserved for 90 days. No significant microcracks exited in any of the longitudinal sections of dentin.

Effectiveness and prognostic factors of different minimally invasive surgeries for vertebral compression fractures.

BACKGROUND: The aging of China's population has led to an increase in the incidence rate of osteoporosis, which indirectly increases the risk of OVCF in osteoporosis patients. Low back pain is the main symptom of OVCF, and severe patients can further develop kyphosis. Although the conservative treatment of OVCF can effectively control the patient's condition, long-term bed rest will increase the risk of OVCF complications. Minimally invasive surgery is a common solution for OVCF. METHODS: 100 OVCF patients admitted to our hospital from January 2021 to January 2022 are selected for analysis and randomly divided into PVP group and PKP group, 50 cases in each group. The PVP group and the PKP group undergo PVP and PKP operations respectively. The differences in efficacy indicators and adverse reactions are compared, and the multivariate Logistic regression method is used to analyze the influencing factors of postoperative secondary fractures in patients with vertebral compression fractures. RESULTS: Compared with the PVP group, the total effective rate of PKP group is significantly increased, and the VAS, ODI score, kyphotic Cobb Angle, lateral distribution rate of bone cement and bone cement leakage rate are significantly decreased (P < 0.05). Age ≥ 80 years old, female, glucocorticoid use, lateral distribution of bone cement and bone cement leakage are significantly higher in the proportion of secondary fractures and are independent risk factors for postoperative secondary fractures in patients with OVCF. CONCLUSION: PKP surgery has a higher efficacy in the treatment of OVCF patients, which can reduce the incidence of pain, adverse reactions and promote the recovery of kyphotic Cobb Angle. PKP surgery has a higher value in the treatment of OVCF. In addition, the influencing factors of secondary fracture after minimally invasive surgery in OVCF patients include age, gender, glucocorticoid use, bone cement distribution pattern, bone cement leakage, etc.

[Analysis of Periodontal Status and Salivary Microbial Diversity in Patients with Rheumatoid Arthritis].

OBJECTIVE: To observe the periodontal status and salivary microbial diversity in patients with rheumatoid arthritis, and to analyze the relationship between the composition of oral microflora in patients with RA and the incidence of rheumatoid arthritis. METHODS: 24 patients who were diagnosed as rheumatoid arthritis were enrolled in the experimental group, and 20 healthy persons were enrolled in the control group. The periodontal index was recorded and non-irritating saliva was collected. DNA was extracted and high-throughput sequencing was performed. RESULTS: There were no significant differences in periodontal indices between the RA group and the control group. After analysis of salivary microorganisms in RA patients and control group, there was no significant difference in salivary microbial diversity between RA patients and control group. At the phylum level, 13 phyla were found, including Firmicutes (30.2%), Proteobacteria (29.3%), Bacteroidetes (23.8%), Fusobacteria (7.3%), Actinobacteria (5.6%) as dominant bacteria. Bacteroidetes (P=0.04) and spirochoetes (P=0.01) were significantly higher in the RA group. A total of 144 genus were found, and 12 dominant genus were found. 11 genuses were found to have significant difference between the RA group and the control. At the genus level, Prevotella (P=0.03), Porphyromonas (P=0.005 7), Tannerella (P=0.001 9) and Treponema (P=0.010) were significantly higher in the RA group. Salivary microbial community similarity in the RA group was significantly higher than that in the control group. CONCLUSION: Compared with healthy people, RA patients had higher periodontal inflammation indices, but there was no statistical difference. The oral saliva of patients with rheumatoid arthritis has a unique microbial diversity structure. This result provides a new insight for understanding the pathogenesis of rheumatoid arthritis.

Biocompatible Reduction and pH Dual-Responsive Core Cross-Linked Micelles Based on Multifunctional Amphiphilic Linear-Hyperbranched Copolymer for Controlled Anticancer Drug Delivery.

Novel strategy has been developed for fabricating the biocompatible reduction and pH dual-responsive core cross-linked (CCL) micelles as drug delivery system (DDS) for the controlled anticancer drug delivery, via the atom transfer radical polymerization (ATRP) of tert-butyl acrylate (tBA) with N,N'-bis(acryloyl)cystamine (BACy) as cross-linker and a multifunctional amphiphilic linear-hyperbranched copolymer as macroinitiator, which was synthesized via the self-condensing vinyl copolymerization (SCVCP) of tBA and p-chloromethylstyrene (CMS) with a poly(ethylene glycol) (PEG) based initiator (mPEG-Br). The hydrolyzed core cross-linked (HCCL) micelles were obtained as DDS for doxorubicin (DOX) by hydrolysis the tBA units into acrylic acid (AA) ones. The in vitro release performance showed that higher GSH concentration and/or lower pH value would lead to a faster and more efficient DOX release, meaning their reduction and pH dual-responsiveness. Therefore, the proposed HCCL micelles are expected to be potential anticancer drug-carriers for tumor microenvironment responsive controlled delivery.

A comprehensive profiling of supragingival bacterial composition in Chinese twin children and their mothers.

To investigate the factors influencing the oral microbiome, 16 twin pairs and their mothers were enrolled in this study. There were 7 monozygotic (MZ) twins and 9 dizygotic (DZ) twins, with an average age of 6.18 ± 3.5. Supragingival plaques and caries tissues were collected and the 16S rDNA was analyzed by 454 pyrosequencing. A total of 18 phyla and 179 genuses were found. Caries children harbored a higher portion of Actinobacteria than caries-free ones, and one lineage was found to be less abundant in the caries tissues compared to the supragingival plaque at each level from the phylum down to the genus level, which was Fusobacteria at Phylum, Fusobacteriia at Class, Fusobacteriales at Order, Leptotrichiaceae at Family and Leptotrichia at genus level. The adults harbored a significantly higher portion of Treponema, which may be related to adult periodontitis. The phylogenetic tree showed that there was a high similarity of oral microbiota within co-twins, but no significant difference was detected between MZ and DZ twins. Also, the similarity level of primary dentition children to their mother was significantly higher than that of mixed dentition children, suggesting that environmental factors may have a stronger impact than the genetic factors on the constitution of the oral microbiome.

pH/Reductant Dual-Responsive Core-Cross-Linked Micelles via Facile in Situ ATRP for Tumor-Targeted Delivery of Anticancer Drug with Enhanced Anticancer Efficiency.

Anticancer drugs cause severe side effects on normal tissues and organs due to their nonspecific delivery. Thus, tumor-targeting delivery of anticancer drugs remains a serious challenge in chemotherapy. Here a facile strategy was established for the pH/reductant dual-responsive core-cross-linked (CCL) micelles for tumor-targeted delivery of anticancer drug, via in situ atom transfer radical polymerization (ATRP). In the in vitro controlled release experiments with doxorubicin (DOX) as a model drug, the premature drug leakage rate was only 13.4% in the physiological medium within 36 h, while the cumulative release rate in the stimulated tumor microenvironment reached 78.7%, demonstrating the excellent tumor microenvironment responsive controlled release behavior upon acidic medium with high GSH level. As a folate receptor (FR) mediated targeting drug delivery system (DDS), the micelles showed excellent cytocompatibility, and enhanced anticancer efficiency after loading of DOX, compared with free DOX.

Simulations reveal the role of composition into the atomic-level flexibility of bioactive glass cements.

Bioactive glass ionomer cements (GICs), the reaction product of a fluoro-alumino-silicate glass and polyacrylic acid, have been in effective use in dentistry for over 40 years and more recently in orthopaedics and medical implantation. Their desirable properties have affirmed GIC's place in the medical materials community, yet are limited to non-load bearing applications due to the brittle nature of the hardened composite cement, thought to arise from the glass component and the interfaces it forms. Towards helping resolve the fundamental bases of the mechanical shortcomings of GICs, we report the 1st ever computational models of a GIC-relevant component. Ab initio molecular dynamics simulations were employed to generate and characterise three fluoro-alumino-silicate glasses of differing compositions with focus on resolving the atomic scale structural and dynamic contributions of aluminium, phosphorous and fluorine. Analyses of the glasses revealed rising F-content leading to the expansion of the glass network, compression of Al-F bonding, angular constraint at Al-pivots, localisation of alumino-phosphates and increased fluorine diffusion. Together, these changes to the structure, speciation and dynamics with raised fluorine content impart an overall rigidifying effect on the glass network, and suggest a predisposition to atomic-level inflexibility, which could manifest in the ionomer cements they form.

Superparamagnetic Reduction/pH/Temperature Multistimuli-Responsive Nanoparticles for Targeted and Controlled Antitumor Drug Delivery.

Multistimuli-responsive polymeric nanoparticles with core-shell architecture were prepared by coating superparamagnetic Fe3O4 nanoparticle cores with reduction/pH dual-responsive poly(methacrylic acid) (PMAA) as shells and thermal-responsive poly(N-isopropylacrylamide) (PNIPAM) as a "gatekeeper" on the surface via two-stage distillation precipitation polymerization. The Fe3O4@PMAA nanoparticles were synthesized using N,N-bis(acryloyl)cystamine (BACy) as cross-linker which would be easily biodegradable in the presence of dithiothreitol (DTT) or glutathione (GSH). The cumulative release profile was investigated under different conditions, such as media pH, reductive agents, and temperature, with doxorubicin hydrochloride (DOX) as a model anticancer drug. They showed a low leakage of DOX at pH 7.4 (less than 11% in 24 h), while the release significantly accelerated at pH 5.0 and 10 mM GSH (over 60% in 5 h), realizing the "triggered release" of drug in the targeted tissues. The nanoparticles exhibited excellent biocompatibility while the DOX-loaded nanoparticles showed great promise of antitumor efficacy as free DOX by the MTT assay and CLSM analysis. The results suggest that the novel biodegradable nanoparticles with high drug loading capacity and multiresponsive controlled release capability could serve as an excellent gene/drug delivery system candidate for cancer therapy.

Fluorescent Copolymer-Based Prodrug for pH-Triggered Intracellular Release of DOX.

A novel water-soluble pH stimuli-responsive fluorescent copolymer of P(PEGMA-b-(MAH-co-Rh6GEAm)) was synthesized by two-step sequential RAFT polymerization. The prodrug with drug content of 0.1560 mg/mg was prepared by coupling doxorubicin (DOX) onto the copolymer via acid-cleavable hydrazone bond, formed between the carbonyl group of DOX and abundant hydrazide functional groups in the copolymer. The amphiphilic DOX-conjugated prodrug (P(PEGMA-b-(MAH-DOX-co-Rh6GEAm))) could easily form a micelle in water with Dh of less than 100 nm. It could be transported into HepG2 cells and release DOX without burst release, while the leakage of DOX can be avoided in the simulated normal physiological media. Furthermore, its fluorescence intensity experienced a reversible change with the transformation of the media pH. The better biocompatibility, pH stimuli-responsiveness, and the strong fluorescence at low pH media make the nanoparticles a potential platform for the controlled release of anticarcinogens and real-time fluorescent imaging of tumor tissues.

Multiple effects of dose-related GM-CSF on periodontal resorption in deep-frozen grafted teeth: A reverse study.

Autologous tooth grafting is a dental restorative modality based on periodontal ligament healing.Human periodontal ligament stem cells(PDLSCs) are involved in the formation and remodeling of periodontal tissue.Based on previous findings, the proliferation and differentiation of processing cryopreserved periodontal ligament stem cells (PDLSCs) exhibit similarities to those of fresh cells. However, there is evident absorption in the transplanted frozen tooth's roots and bones, with the underlying cause remaining unknown. Granulocyte macrophage colony-stimulating factor(GM-CSF) is named for its produce granulocyte and macrophage precursors from bone marrow precursors, and it also serves as one of the regulatory factors in inflammatory and osteoclast formation. This study aimed to investigate changes in GM-CSF expression in frozen PDLSCs (fhPDLSCs) and evaluate the impact of GM-CSF on PDLSCs with respect to cellular activity and osteogenic ability. The role of GM-CSF in periodontal absorption was further speculated by comparing with IL-1ß. The results revealed a significant increase in GM-CSF levels from fhPDLSCs compared to fresh cells, which exhibited an equivalent inflammatory stimulation effect as 1 ng/ml IL-1ß. Cell viability also increased with increasing concentrations of GM-CSF; however, the GM-CSF from fhPDLSCs was not sufficient to significantly trigger osteoclastic factors. Considering its interaction with IL-1ß and positive feedback mechanism, environments with high doses of GM-CSF derived from fhPDLSCs are more likely to activate osteoclastic responses.Therefore, for frozen tooth replantation, great attention should be paid to anti-inflammation and anti-infection.GM-CSF may serve as a potential therapeutic target for inhibiting periodontal resorption in delayed grafts.

Mechanism of bacterial communities regulating litter decomposition under climate warming in temperate wetlands.

Plant litter decomposition plays a crucial role in the flow of nutrients and energy in ecosystems. However, the mechanism of bacterial communities regulating litter decomposition under climate warming in temperate wetlands remains largely unknown. The objective of this study was to determine the influences of temperature on decomposition and the bacterial regulatory mechanism under climate warming in temperate wetlands. In this study, we conducted a 1.5-year litter decomposition warming experiment using dominant plant species in the temperate lake wetlands of the North China Plain. Our results showed that the decomposition rate (K) had a significant positive correlation with temperature, and the non-additive effects of litter decomposition could be clearly observed in the mixtures of Phragmites australis and Typha angustata, especially under warming conditions. Among the three types of litter, Phragmites australis had the highest temperature sensitivity (2.75), which meant that it would be most affected by climate change in the future. The concentrations of C and N showed a significant positive correlation with the decomposition rate and were mainly driven by Proteobacteria and Firmicutes, while the concentration of lignin and the lignin:N ratio had a highly significant negative correlation with the decomposition rate and were mainly driven by Bacteroidota and Actinobacteriota. Furthermore, the bacterial cooccurrence network revealed that the abundance of Firmicutes and Desulfobacterota increased significantly, and positive edges accounted for 67.81% ~ 71.14% under warming conditions. The bacterial networks of litter decomposition were mainly composed of symbiotic relationships, and warming was helpful for improving the positive correlations and symbiotic relationships of bacterial flora and sped up the litter decomposition process. These results will be helpful to further understand the mechanism of bacterial communities regulating litter decomposition under climate warming in temperate wetland ecosystems.

3D Printing Technology with Reverse Guide Design in Autogenous Tooth Transplantation: An in vitro Pictorial Report.

The success of autologous tooth transplantation depends on the activity of the periodontal ligament of the donor tooth. Its activity decreases with a longer exposure time. In order to reduce the exposure time of the donor tooth and quickly prepare the alveolar fossa highly matching with the donor tooth root, the clinical data of cone-beam CT (CBCT) was imported into Mimics 21.0 software in this study to obtain three-dimensional (3D) images of the jaw tissue structure. The images were used to extract the target area and select the target tooth. By analysing the information of the recipient region and the donor region, 3-Matic 13.0 software was used to implant the donor virtual into the target region, and restrictive personalised guidance was designed. Subsequently, the surgical guide template was printed by 3D printing technology, and the alveolar fossa was rapidly prepared in vitro. After the operation, the donor tooth was matched with the complete alveolar cavity using 3-Matic13.0 software. The depth deviation of the prepared alveolar cavity was measured within 2.0 mm, and the width deviation was about 1.0 mm. The maximum width deviation is 2.88 mm due to the tilt of the roots. With a high matching degree to the donor tooth root, it needs further and larger clinical studies. Key Words: CBCT, Tooth autotransplantation, 3D printing technology, Computer-aided imaging, Periodontal ligament.

A virtual surgical prototype system based on gesture recognition for virtual surgical training in maxillofacial surgery.

BACKGROUND: Virtual reality (VR) technology is an ideal alternative of operation training and surgical teaching. However, virtual surgery is usually carried out using the mouse or data gloves, which affects the authenticity of virtual operation. A virtual surgery system with gesture recognition and real-time image feedback was explored to realize more authentic immersion. METHOD: Gesture recognition technology proposed with an efficient and real-time algorithm and high fidelity was explored. The recognition of hand contour, palm and fingertip was firstly realized by hand data extraction. Then, an Support Vector Machine classifier was utilized to classify and recognize common gestures after extraction of feature recognition. The algorithm of collision detection adopted Axis Aligned Bounding Box binary tree to build hand and scalpel collision models. What's more, nominal radius theorem (NRT) and separating axis theorem (SAT) were applied for speeding up collision detection. Based on the maxillofacial virtual surgical system we proposed before, the feasibility of integration of the above technologies in this prototype system was evaluated. RESULTS: Ten kinds of signal static gestures were designed to test gesture recognition algorithms. The accuracy of gestures recognition is more than 80%, some of which were over 90%. The generation speed of collision detection model met the software requirements with the method of NRT and SAT. The response time of gesture] recognition was less than 40 ms, namely the speed of hand gesture recognition system was greater than 25 Hz. On the condition of integration of hand gesture recognition, typical virtual surgical procedures including grabbing a scalpel, puncture site selection, virtual puncture operation and incision were carried out with realization of real-time image feedback. CONCLUSION: Based on the previous maxillofacial virtual surgical system that consisted of VR, triangular mesh collision detection and maxillofacial biomechanical model construction, the integration of hand gesture recognition was a feasible method to improve the interactivity and immersion of virtual surgical operation training.

Qualitative assessment of microstructure and Hertzian indentation failure in biocompatible glass ionomer cements.

Discs of biocompatible glass ionomer cements were prepared for Hertzian indentation and subsequent fracture analyses. Specifically, 2 × 10 mm samples for reproducing bottom-initiated radial fracture, complemented by 0.2 × 1 mm samples for optimal resolution with X-ray micro tomography (µCT), maintaining dimensional ratio. The latter allowed for accurate determination of volumetric-porosity of the fully cured material, fracture-branching through three Cartesian axes and incomplete bottom-initiated cracking. Nanocomputed tomography analyses supported the reliability of the µCT results. Complementary 2-dimensional fractographic investigation was carried out by optical and scanning electron microscopies on the larger samples, identifying fracture characteristics. The combined 3-D qualitative assessment of microstructure and fractures, complemented by 2-D methods, provided an increased understanding of the mechanism of mechanical failure in these cements. Specifically, cracks grew to link pores while propagating along glass-matrix interfaces. The methodological development herein is exploitable on related biomaterials and represents a new tool for the rational characterisation, optimisation and design of novel materials for clinical service.

A digital intervention using virtual reality helmets to reduce dental anxiety of children under local anesthesia and primary teeth extraction: A randomized clinical trial.

INTRODUCTION: Behavior management of children during dental treatment is an important but challenging issue. As a new technique, VR has been applied in pediatric dental anxiety. But there is no final conclusion whether VR reduces children's dental anxiety. METHODS: The aim of the study is to assess the effectiveness of a digital intervention using virtual reality (VR) helmets on dental anxiety, pain perception, and behavior triggered for children, as well as occurrence of simulator sickness in local anesthesia and primary teeth extraction. A total of 128 children, who needed primary teeth extraction under local anesthesia, were randomly allocated into two groups: use VR helmets and traditional behavior guidance procedures (control). Modified Child Fear Survey Schedule Dental Subscale (CFSS-DS), Wong-Baker FACES Pain Scale, Houpt Scale, and Simulator sickness questionnaire (SSQ) were used to assess children's dental anxiety, pain perception, and behavior triggered and occurrence of simulator sickness. RESULTS: CFSS-DS score in the VR group was significantly decreased after dental treatment (34.58±6.90 before operation and 32.32±15.58 after operation, p = .02). The score of Wong Baker Scale in the VR group (3.47±0.76) was significantly lower than that in the control group (5.56±1.13, p = .015). There was no significant difference in the Houpt Behavior Scale score and the SSQ score between the VR group and the control group (p = .35, p = .305). CONCLUSION: The use of VR helmets in primary teeth extraction can significantly reduce dental anxiety and pain perception in children without occurrence of simulator sickness.

Introducing the thin and ultrathin submental artery perforator flaps for precise reconstruction following T1-2 oral cavity cancer resection.

We reported a case series of thin (n = 32) and ultrathin (n = 4) submental artery perforator flaps (SMAPF) for precise reconstruction following T1-2 oral cavity cancer resection. The former is indicated for tongue reconstruction involving the tongue tip, and buccal lining replacement involving the mouth corner, while the latter is specifically tailored to restore superficial buccal defects after resection of small early cancer originating from oral submucous fibrosis. All flaps survived. Most flap reconstructions reached satisfactory cosmetic results. Based on this series, we discussed the indications of thin and ultrathin SMAPFs in intaoral reconstruction, and surgical tips for flap thinning.

Proline-rich protein from S. mutans can perform a competitive mineralization function to enhance bacterial adhesion to teeth.

A proline-rich region was found in Streptococcus mutans (S. mutans) surface antigen I/II (Ag I/II). The functions of this region were explored to determine its role in the cariogenic abilities of S. mutans; specifically, the proline-rich region was compared with human amelogenin. The full-length amelogenin genes were cloned from human (AmH) and surface antigen I/II genes from S. mutans. Then, the genes expressed and purified. We analyzed the structure and self-assembly ability of AmH and Ag I/II, compared their capacities to induce mineralization, and assessed the adhesion ability of S. mutans to AmH- and Ag I/II-coated tooth slices. AmH formed ordered chains and net frames in the early stage of protein self-assembly, while Ag I/II formed irregular and overlapping structures. AmH induced mineralization possessed a parallel rosary structure, while Ag I/II-induced mineralization is rougher and more irregular. The S. mutans adhesion assay indicated that the adhesion ability S. mutans on the Ag I/II-induced crystal layer was significantly higher than that on the AmH-induced crystal layer. S. mutans' Ag I/II may have evolved to resemble human amelogenin and form a rougher crystal layer on teeth, which play a competitive mineralization role and promotes better bacterial adhesion and colonization. Thus, the cariogenic ability of S. mutans Ag I/II is increased.

Insights into the minimization of excess sludge production in micro-aerobic reactors coupled with a membrane bioreactor: Characteristics of extracellular polymeric substances.

The production of excess sludge by the activated sludge system of wastewater treatment plants is a problem. In this study, the EPS characteristics on production and degradation were investigated in the real-scale food processing wastewater treatment system (i.e., a micro-aerobic reactor coupled with a membrane bioreactor (MAR-MBR)) with a treatment capacity of 150 t d-1, which could cater for the low production of excess sludge (i.e., 9 t·a-1; 76% moisture content). The total organic carbon concentrations in the different EPS fractions were in the following order: soluble EPS (S-EPS) < loosely bound EPS (LB-EPS) < tightly bound EPS (TB-EPS). Although the components (e.g., protein and humic acid-like substances) of each EPS fraction changed significantly throughout the MAR-MBR process owing to the low production of excess sludge, the degrees of change in S-EPS, LB-EPS, and TB-EPS were significantly different from the corresponding change in their relative molecular weights. Furthermore, the microbial community composition was beneficial for the release and degradation of EPS, and the regulation of gene functions via the MAR-MBR enhanced this process.

Composition-Nanostructure Steered Performance Predictions in Steel Wires.

Neutron scattering in combination with scanning electron and atomic force microscopy were employed to quantitatively resolve elemental composition, nano- through meso- to metallurgical structures and surface characteristics of two commercial stainless steel orthodontic archwires-G&H and Azdent. The obtained bulk composition confirmed that both samples are made of metastable austenitic stainless steel type AISI 304. The neutron technique's higher detection sensitivity to alloying elements facilitated the quantitative determination of the composition factor (CF), and the pitting resistance equivalent number (PREN) for predicting austenite stability and pitting-corrosion resistance, respectively. Simultaneous neutron diffraction analyses revealed that both samples contained additional martensite phase due to strain-induced martensite transformation. The unexpectedly high martensite content (46.20 vol%) in G&H was caused by combination of lower austenite stability (CF = 17.37, p = .03), excessive cold working and inadequate thermal treatment during material processing. Together, those results assist in revealing alloying recipes and processing history, and relating these with corrosion resistance and mechanical properties. The present methodology has allowed access to unprecedented length-scale (µm to sub-nm) resolution, accessing nano- through meso-scopic properties. It is envisaged that such an approach can be extended to the study and design of other metallic (bio)materials used in medical sciences, dentistry and beyond.

Cell physiological effects of glass ionomer cements on fibroblast cells.

The cytotoxicity of glass ionomer cements (GICs) was investigated using a novel, cost-effective, easy-to-perform and standardized test. GIC rings were made using in-house designed, custom-made moulds under sterile conditions; 10 with Fuji Equia and 10 with Fuji Triage capsules, placed in direct contact with primary human gingival fibroblasts (HGF) and immortalized human fibroblasts (HFF1). On day 1, 4, 14 and 21, an AlamarBlue® (resazurin) assay was completed towards determining the effects of the GICs on metabolic activities of the cells, whilst cell morphology was examined by light microscopy. The influence of the compounds released from the GIC rings on cell physiological effects (viability, proliferation and adhesion) during 24 h incubation was further investigated by impedimetry. Result trends obtained from this battery of techniques were complementary. At 100 v/v% concentration, the released compounds from Equia were strongly cytotoxic, while at lower concentration (0, 4, 20 v/v%) they were not cytotoxic. In contrast, Triage elicited only slightly transient cytotoxicity. The method proposed has been proved as being efficient, reliable and reproducible and may be useful in quick testing of the cytotoxicity of similar biomaterials by using an immortalized cell line.