Oral Galvanism Side Effects: Comparing Alloy Ions and Galvanic Current Effects on the Mucosa-like Model.

The interaction of different dental alloys with the oral environment may cause severe side effects (e.g., burning sensation, inflammatory reactions, carcinogenesis) as a result of oral galvanism. However, the pathogenesis of side effects associated with oral galvanism is still unclear, and the effects of direct current and alloy corrosion ions are considered potentially contributing factors. Therefore, the aim of this study was to systemically compare the damaging effects of (1) galvanism as a synergistic process (direct current + corrosion ions), (2) direct current separately, and (3) corrosion ions separately on an in vitro mucosa-like model based on a cell line of immortalized human keratinocytes (HaCaTs) to reveal the factors playing a pivotal role in dental alloys side effects. For this, we chose and compared the dental alloys with the highest risk of oral galvanism: Ti64-AgPd and NiCr-AgPd. We showed that galvanic current may be the leading damaging factor in the cytotoxic processes associated with galvanic coupling of metallic intraoral appliances in the oral cavity, especially in the short-term period (28 days). However, the contribution of corrosion ions (Ni2+) to the synergistic toxicity was also shown, and quite possibly, in the long term, it could be no less dangerous.

Lagrangian large eddy simulations via physics-informed machine learning.

High-Reynolds number homogeneous isotropic turbulence (HIT) is fully described within the Navier-Stokes (NS) equations, which are notoriously difficult to solve numerically. Engineers, interested primarily in describing turbulence at a reduced range of resolved scales, have designed heuristics, known as large eddy simulation (LES). LES is described in terms of the temporally evolving Eulerian velocity field defined over a spatial grid with the mean-spacing correspondent to the resolved scale. This classic Eulerian LES depends on assumptions about effects of subgrid scales on the resolved scales. Here, we take an alternative approach and design LES heuristics stated in terms of Lagrangian particles moving with the flow. Our Lagrangian LES, thus L-LES, is described by equations generalizing the weakly compressible smoothed particle hydrodynamics formulation with extended parametric and functional freedom, which is then resolved via Machine Learning training on Lagrangian data from direct numerical simulations of the NS equations. The L-LES model includes physics-informed parameterization and functional form, by combining physics-based parameters and physics-inspired Neural Networks to describe the evolution of turbulence within the resolved range of scales. The subgrid-scale contributions are modeled separately with physical constraints to account for the effects from unresolved scales. We build the resulting model under the differentiable programming framework to facilitate efficient training. We experiment with loss functions of different types, including physics-informed ones accounting for statistics of Lagrangian particles. We show that our L-LES model is capable of reproducing Eulerian and unique Lagrangian turbulence structures and statistics over a range of turbulent Mach numbers.

A Comparative Analysis of Neuroprotective Properties of Taxifolin and Its Water-Soluble Form in Ischemia of Cerebral Cortical Cells of the Mouse.

Cerebral ischemia, and, as a result, insult, attacks up to 15 million people yearly in the world. In this connection, the development of effective preventive programs and methods of therapy has become one of the most urgent problems in modern angiology and pharmacology. The cytoprotective action of taxifolin (TAX) in ischemia is well known, but its limitations are also known due to its poor solubility and low capacity to pass through the hematoencephalic barrier. Molecular mechanisms underlying the protective effect of TAX in complex systems such as the brain remain poorly understood. It is known that the main cell types of the brain are neurons, astrocytes, and microglia, which regulate the activity of each other through neuroglial interactions. In this work, a comparative study of cytoprotective mechanisms of the effect of TAX and its new water-soluble form aqua taxifolin (aqTAX) was performed on cultured brain cells under ischemia-like conditions (oxygen-glucose deprivation (OGD)) followed by the reoxygenation of the culture medium. The concentration dependences of the protective effects of both taxifolin forms were determined using fluorescence microscopy, PCR analysis, and vitality tests. It was found that TAX began to effectively inhibit necrosis and the late stages of apoptosis in the concentration range of 30-100 µg/mL, with aqTAX in the range of 10-30 µg/mL. At the level of gene expression, aqTAX affected a larger number of genes than TAX; enhanced the basic and OGD/R-induced expression of genes encoding ROS-scavenging proteins with a higher efficiency, as well as anti-inflammatory and antiapoptotic proteins; and lowered the level of excitatory glutamate receptors. As a result, aqTAX significantly inhibited the OGD-induced increase in the Ca2+ levels in the cytosol ([Ca2+]i) in neurons and astrocytes under ischemic conditions. After a 40 min preincubation of cells with aqTAX under hypoxic conditions, these Ca2+ signals were completely inhibited, resulting in an almost complete suppression of necrotic death of cerebral cortical cells, which was not observed with the use of classical TAX.

The Impact of Impulsive Traffic on Cellular Internet of Things Network Performance Indicators.

The use of wireless sensor networks and the Internet of Things has increased dramatically in the last decade. The sensors measure the required parameters and send them to the data processing centers using one of the various wireless transmission technologies (often using cellular infrastructure) to make the appropriate decision. Files containing measurement information can arrive in bursts simultaneously, which is a critical issue to be aware of. The purpose of this work is to develop and analyze a model to evaluate the effectiveness of an LTE (Long-Term Evolution) cell in serving requests from NB-IoT (Narrowband Internet of things) devices when these requests are received in bursts rather than individually. In the article, the common uses of the Internet of Things in our modern era were discussed, the NB-IoT technology was paid attention to, and a mathematical model to evaluate the performance of an LTE cell in the case of impulsive arrivals of NB-IoT requests was built. Finally, the computational algorithm and numerical evaluation were introduced.

Free Gingival-Bone Graft in the Anterior Maxilla: A Clinical Case Report.

AIM: To present the healing, development, and long-term clinical results after a combined gingival-bone graft as an alternative treatment for the management of critical extraction sites in the esthetic zone. BACKGROUND: To enhance the knowledge of in vivo soft and hard tissue remodeling, in this case report, we observed the healing, development, and long-term clinical results after a case of a combined gingival-bone graft as an alternative treatment for the management of critical extraction sites. CASE DESCRIPTION: Autogenous grafts of gingival and bone tissue were placed in a 56-year-old female patient, where a hopeless upper left central incisor with an evident loss of both the buccal and the palatal bony plates and with endodontic problems was due for extraction. In order to obtain enough autogenous tissue for filling the defect, a cylindrical free gingival and bone graft was retrieved from the retromolar area with a trephine drill, to obtain hard and soft tissues for grafting the postextraction defect. After 6 months, following soft tissue maturation and once esthetic and natural gingival contours were achieved, the surgical site was prosthetically restored with a porcelain fused to a metal bridge and scheduled for regular follow-up. CONCLUSION: No complications were observed either from the donor site or from the recipient site. The post-treatment result was esthetically pleasing, based upon successful architectural stability of both hard and soft tissues. Although more studies are needed to confirm the beneficial use of this approach, the procedure can be considered a viable option in the management of soft and hard tissue remodeling in esthetically compromised cases. CLINICAL SIGNIFICANCE: The gingival-bone graft may be considered as an alternative treatment for the management of critical extraction sites in the esthetic area. How to cite this article: Signore A, Stepanov M, Angelis ND, et al. Free Gingival-Bone Graft in the Anterior Maxilla: A Clinical Case Report. J Contemp Dent Pract 2021;22(5):568-571.

High-level laser therapy versus scalpel surgery in the treatment of oral lichen planus: a randomized control trial.

OBJECTIVE: To compare the clinical effectiveness of various types of high-level laser therapy (HLLT) toward scalpel excision for the surgical treatment of erosive oral lichen planus (OLP). MATERIALS AND METHODS: The total number of 128 individuals were enrolled in the study. The 35 did not meet the inclusion criteria due to malignancy signs and presence of diabetes mellitus. In total, 8 were lost to follow-up, and 10 were excluded from the analysis, due to analgesics intake. This way 75 patients with the erosive form of OLP were analyzed in three intervention groups (Er:YAG, n = 19; Nd:YAG, n = 15; Er:YAG + Nd:YAG combination, n = 20) and one control group with scalpel excision (n = 21). The therapy effectiveness has been assessed based on the comparison of salivary interleukin (IL)-1ß, IL-6 and interferon (IFN)-γ preoperative levels to 14, 30 days, and 2 years postoperation, as well as pain level and time of epithelization. RESULTS: All HLLT groups demonstrated a significantly (p > 0.05) higher IL-1ß, IL-6, IFNγ and pain level reduction and quicker epithelization toward the control group on the 30th day, except Nd:YAG in case of IFNγ level. The highest IL-1ß, IFNγ and pain level reduction and quicker epithelization on the 30th day was observed in Er:YAG group, followed by Er:YAG + Nd:YAG combination, Nd:YAG respectively. However no significant difference was observed between the HLLT groups with regard to IL-6 level reduction. After a 2-year follow-up, no significant difference was observed between all study groups with regard to all variables. CONCLUSION: HLLT yields a superior clinical outcome compared to the scalpel excision for the surgical treatment of oral lichen planus, whereby the Er:YAG has been proposed as the most effective laser type at the end of the first postoperative month. CLINICAL RELEVANCE: For the surgical treatment of erosive OLP the Er:YAG laser may be a preferable treatment option compared to Nd:YAG and scalpel surgery. TRIAL REGISTRATION: The present trial was registered retrospectively in the German Clinical Trials Register, as a member of WHO international clinical trials registry platform, on the 18.03.2020 with the following number: DRKS00020986.

Nonfatal and fatal cardiovascular disease events in CPAP compliant obstructive sleep apnea patients.

PURPOSE: Obstructive sleep apnea (OSA) is suggested to predispose to cardiovascular disease (CVD) events. It is uncertain whether compliance to continuous positive airway pressure (CPAP) treatment could attenuate the risk. We explored this issue in long-term CPAP users and untreated controls. METHODS: Retrospective observational cohort of CPAP-treated and control patients were pairwise matched for gender, age, and apnea-hypopnea index (AHI). The study end point was a composite of nonfatal and fatal CVD events. Cox regression model was used to determine the association between CPAP treatment and event-free survival. RESULTS: A total of 2060 patients (75.8% male, mean age 56.0 ± 10.5 years), of which 76.4% had moderate-severe OSA, were included. In the CPAP-treated group (N = 1030), the median use of CPAP was 6.4 h/day during a median follow-up of 8.7 years. The control group (N = 1030) was followed for a median of 6.2 years after the CPAP treatment had ended. The study end point occurred in 14.4% (N = 148) of the CPAP-treated and in 18.8% (N = 194) of the control patients (p = 0.006). Using the Cox regression model adjusted for gender, age, AHI, body mass index, and history of CVD, hypertension, type 2 diabetes, and chronic obstructive pulmonary disease at baseline, a beneficial association between CPAP treatment and CVD risk was observed (hazard ratio 0.64, confidence interval 95% 0.5-0.8, p < 0.001). CONCLUSIONS: CPAP treatment was associated with a decreased risk of nonfatal and fatal CVD events. Majority of the patients were compliant to CPAP. The association was demonstrated independent from common cardiovascular risk factors and AHI.

Causes of peroneal neuropathy associated with orthopaedic leg lengthening in different canine models.

Peroneal neuropathy is one of the complications of orthopaedic leg lengthening. Methods of treatment include slowing of distraction and decompression both of which may lead to additional complications. The purpose of this study was to analyse the changes in histologic peroneal nerve structure during experimental orthopaedic lengthening using various modes of manual or automatic distraction. The obtained data provide the basis for better understanding of peroneal neuropathy pathogenesis and refinement of prophylaxis and preventive treatment protocols. Four experimental models of canine leg lengthening using the Ilizarov fixator were studied: 1 (n = 10)-manual distraction-1 mm/day divided into four increments; 2 (n = 12)-automatic distraction-1 mm/day in 60 increments, 3 (n = 9) and 4 (n = 9)-increased rate of high frequency automatic distraction: 3 mm/day in 120 and 180 increments, respectively. In peroneal nerves semi-thin sections cross-sectional fascicular areas, content of adipocytes in epineurium, endoneurial vascularisation, morphometric parameters of nerve fibres were assessed by computerised analysis at the end of distraction and of consolidation periods and 30 days after fixator removal. In Groups 1-2 massive nerve fibre degeneration along with epineural vessels obliteration was revealed in two cases from 22, whereas in Groups 3-4 there were 10 from 18 (p < 0.01). Injuries of perineurium and endoneurial vessels were noted in Group 3, and long-lasting thinning of nerve fascicles in Group 4. The decrease in epineurial fat tissue was revealed in all groups, more drastic in 3. Modifications and injuries of nerve sheaths and blood vessels depending on distraction rate and frequency contribute to peroneal neuropathy. Its mechanical, circulatory and metabolic causes are discussed.

The effects of tibial fracture and Ilizarov osteosynthesis on the structural reorganization of sciatic and tibial nerves during the bone consolidation phase and after fixator removal.

Reactive and adaptive changes in mechanically uninjured nerves during fracture healing have not been studied previously although the status of innervation is important for bone union and functional recovery. This study explores whether subclinical nerve fibre degeneration occurs in mechanically uninjured nerves in an animal fracture model and to quantify its extent and functional significance. Twenty-four dogs were deeply anaesthetized and subjected to experimental tibial shaft fracture and Ilizarov osteosynthesis. Before fracture and during the experiment, electromyography was performed. In 7, 14, 20, 35-37 and 50 days of fixation and 30, 60-90 and 120 days after fixator removal, the dogs were euthanized. Samples from sciatic, peroneal and tibial nerves were processed for semithin section histology and morphometry. On the 37th postoperative day, M-response amplitudes in leg muscles were 70 % lower than preoperative ones. After fixator removal, these increased but were not restored to normal values. There were no signs of nerve injuries from bone fragments or wires from the fixator. The incidence of degenerated myelin fibres (MFs) was less than 12 %. Reorganization of Remak bundles (Group C nerve fibres-principally sensory) led to a temporal increase in numerical nerve fibre densities. Besides axonal atrophy, the peroneal nerve was characterized with demyelination-remyelination, while tibial nerve with hypermyelination. There were changes in endoneural vessel densities. In spite of minor acute MF degeneration, sustained axonal atrophy, dismyelination and retrograde changes did not resolve until 120 days after fracture healing. Correlations of morphometric parameters of degenerated MF with M-response amplitudes from electromyography underlie the subclinical neurologic changes in functional outcomes after tibial fractures even when nerves are mechanically uninjured.

Muscle metabolism during tibial lengthening with regular and high distraction rates.

INTRODUCTION: Muscle regeneration is promoted when the Ilizarov method is used for limb lengthening and deformity correction, but the regenerative ability of muscles decreases when achieving large amounts of elongation. Much research has been dedicated to studying the capabilities of muscles under lengthening, but no reports are available that investigate the muscle metabolism. We supposed that energy turnover would be activated in skeletal muscles under lengthening as a response to distraction, and the activity of the energy turnover would grow in proportion to the increase in the distraction rate or amount. MATERIALS AND METHODS: We compared the metabolism of canine anterior tibial muscles (ATMs) by regular and 3-mm high-frequency bone distraction in 30 dogs to obtain 14.5 ± 0.8% lengthening from the initial tibial length. Group 1 (n = 12) had manual lengthening with a rate of 1 mm per day. Three millimeters per day was produced with 120 increments in automated mode in group 2 (n = 12). An intact group (n = 6) served as controls. ATMs were harvested at the end of distraction, after 30 days of fixation, and 30 days after frame removal. We assessed the activity of lactate dehydrogenase, creatine phosphokinase, glucoso-6-phosphate dehydrogenase, and catalase and calculated the concentration of malone dialdehyde, sarcoplasmic and contractile proteins in the ATM extract. RESULTS: Energy turnover reactions were activated in the ATM as a response to distraction forces, but the activity of the energy turnover did not grow proportionally to the increased distraction rate. Levels of sarcoplasmic and contractile proteins in the ATM decreased insignificantly in both groups. CONCLUSIONS: High-frequency 3-mm daily lengthening results in compensatory energy turnover changes in the muscle, sufficient for prevention of catabolic processes.

Histomorphometric analysis of knee synovial membrane in dogs undergoing leg lengthening by classic Ilizarov method and rapid automatic distraction.

PURPOSE: This pilot study aimed to test the theory that different lengthening methods affect the microscopic structure of knee joint synovium in diverse ways. METHODS: This was a descriptive and analytical cross-sectional study of synovium carried out in two experimental models of canine leg lengthening using the Ilizarov fixator. Group 1 (n = 6) used manual gradual distraction most commonly used in clinical practice at one millimetre/day divided into four equal increments, 0.25 mm at each increment. Group 2 (n = 7) used an increased rate of automatic distraction at three millimetres/day divided in 120 increments, 0.025 mm at each increment. At the end of distraction and after fixator removal, the animals were euthanised. Control was via intact dogs. The thickness of the synovial lining layer, number of synovial cell rows, and numerical density of subsynovial microvessels were assessed in digital images for semiautomated computerised analysis of semi-thin sections stained with toluidine blue and methylene blue-basic fuchsin. Comparison of synovitis manifestation was made with grading scale. The vascular and nerve changes in the subsynovial layer were also compared. RESULTS: Group 1 developed marked synovitis, synovium hypervascularisation, degeneration of the nerve fibres in subsynovial nerves with the tendency to regeneration. Group 2 had moderate to mild degree of synovitis with progressive degenerative changes in subsynovial vessels and nerves. CONCLUSION: Both methods used are unfavourable for the state of the joint synovium, but modify it in different ways.