An In Vitro Evaluation of the Smear Layer Removal Efficacy of Three Different Chemical Decalcifying Agents on Periodontally Compromised Root Surfaces: A Scanning Electron Microscopy Study.

AIM: Aim of the current research was to assess the smear layer removal efficacy of SofScale, Carisolv gel, and QMix chemical decalcifying substances on periodontally weakened radicular surfaces. MATERIALS AND METHODS: The sample size constituted 60 recently extracted periodontally compromised teeth having a poor prognosis. The samples were allocated at random to one of the following three groups (20 in each): Group I: Scaling and root planing (SRP) with SofScale, Group II: SRP with Carisolv gel, and group III: SRP with QMix. The surfaces thus subjected to treatment were washed with 20 mL of saline and the crown portion was detached at the cementoenamel junction (CEJ). Following this, samples were horizontally and vertically segmented employing a diamond circular disk with 150-200 µm thickness. Every sample segment was subjected to rinsing in normal saline and positioned in 2.5% glutaraldehyde solution in 0.1 M phosphate buffer at a pH of 7.4 for at least 24 hours. Samples were evaluated in a scanning electron microscopy (SEM) at a magnification of 2000×, and photomicrographs were assessed to establish the degree of radicular biomodification by eliminating the smear layer. RESULTS: QMix group showed the highest smear layer elimination at 3.56 ± 0.13 in pursuit by Carisolv gel at 3.64 ± 0.11 and SofScale group with 4.68 ± 0.08. The differences amid the groups were statistically significant with p <0.001. On multiple contrast assessments of smear layer elimination effectiveness of the dissimilar chemical decalcifying substances employing Tukey's HSD, statistically significant differences were noted between group I and group II, as well as group I and group III (p <0.001). However, there were no significant differences between group II and group III (p >0.001). CONCLUSION: In conclusion, QMix was noted to have a superior smear layer elimination capacity in comparison with the radicular surfaces conditioned with Carisolv and SofScale. CLINICAL SIGNIFICANCE: Modifying the surface of teeth by radicular conditioning causes the enhanced attachment of connective tissues coupled with progression in the final aim of reconstructive periodontal therapy. The utility of chemical substances along with physical management characterizes the probability of reduced trauma during treatment, avoiding the sacrifice of radicular portions of teeth.

Knowledge, Awareness, and Attitude among Practicing Orthodontist on Teledentistry during COVID Pandemic in Kerala: A Cross-Sectional Survey.

BACKGROUND: Considering the gravity of coronavirus disease 2019 (COVID-19) and its potential to unfold within the dental workplace or institutions, a shift from traditional dental practice to a newer method is needed. Teledentistry is widely being practiced in this pandemic era for the diagnosis and to give instructions to the patients. Hence, an attempt has been made to explore the knowledge, attitude, and awareness of practicing orthodontists regarding the usage of teledentistry during COVID lockdown, in Kerala. MATERIALS AND METHODS: A cross-sectional, descriptive study was done on about 150 orthodontic professionals. A pretested, self-organized, close-ended survey was managed through online stages that comprised of 15 questions. The information gathered was assembled in a systematic way and investigated regarding recurrence and Chi-square test was utilized for the examination of frequencies. RESULTS: It was observed that 93.3% orthodontic practitioners had knowledge regarding teledentistry and a positive attitude toward teledentistry was shown by younger age group practitioners and those who were working in institutions (P < 0.05). 77.3% believed that teledentistry can save dentist's time and 71.3% responded that the new technology can be helpful in reducing the cost of treatment for patients. CONCLUSION: The knowledge, awareness, and attitudes were discovered to be acceptable among the orthodontic practitioners. Younger practitioners had more positive attitude toward teledentistry, and there was an overall positive attitude for using teledentistry as a temporary alternate for direct patient contact in COVID-19 pandemic time.

NOX4 Mediates Pseudomonas aeruginosa-Induced Nuclear Reactive Oxygen Species Generation and Chromatin Remodeling in Lung Epithelium.

Pseudomonas aeruginosa (PA) infection increases reactive oxygen species (ROS), and earlier, we have shown a role for NADPH oxidase-derived ROS in PA-mediated lung inflammation and injury. Here, we show a role for the lung epithelial cell (LEpC) NOX4 in PA-mediated chromatin remodeling and lung inflammation. Intratracheal administration of PA to Nox4flox/flox mice for 24 h caused lung inflammatory injury; however, epithelial cell-deleted Nox4 mice exhibited reduced lung inflammatory injury, oxidative stress, secretion of pro-inflammatory cytokines, and decreased histone acetylation. In LEpCs, NOX4 was localized both in the cytoplasmic and nuclear fractions, and PA stimulation increased the nuclear NOX4 expression and ROS production. Downregulation or inhibition of NOX4 and PKC δ attenuated the PA-induced nuclear ROS. PA-induced histone acetylation was attenuated by Nox4-specific siRNA, unlike Nox2. PA stimulation increased HDAC1/2 oxidation and reduced HDAC1/2 activity. The PA-induced oxidation of HDAC2 was attenuated by N-acetyl-L-cysteine and siRNA specific for Pkc δ, Sphk2, and Nox4. PA stimulated RAC1 activation in the nucleus and enhanced the association between HDAC2 and RAC1, p-PKC δ, and NOX4 in LEpCs. Our results revealed a critical role for the alveolar epithelial NOX4 in mediating PA-induced lung inflammatory injury via nuclear ROS generation, HDAC1/2 oxidation, and chromatin remodeling.

Assessment of the Effectiveness of Different Fluoride-releasing Bonding Agents on Prevention of Enamel Demineralization around Orthodontic Bracket: An In Vitro Study.

AIM: The aim of the current research was to evaluate the efficacy of different fluoride-releasing bonding products in preventing enamel demineralization around orthodontic brackets by using a scanning electron microscope (SEM). MATERIALS AND METHODS: This research was performed using 80 healthy human premolar teeth that were extracted in course of orthodontic therapy. Until use, the sample premolars were subjected to storage in 0.1% thymol. Each premolar was thereafter cleansed with pumice for 10 seconds. Stainless steel brackets for premolars were employed. The 80 samples were allocated at random to one of the four groups (20 in each) as follows: Group I, control; group II, Transbond Plus color change adhesive; group III, GC Fuji Ortho LC; and group IV, Vitremer. An hour following bonding, all samples were subjected to pH cycling at a temperature of 37°C for a 14-day period. The premolar teeth were assessed below SEM. Analysis was performed with the one-way analysis of variance. Statistical significance was set at a p-value less than 0.05. RESULTS: The extreme area of demineralization was abridged by the use of Transbond™ Plus color change adhesive (108.19 ± 0.68), trailed by GC Fuji Ortho LC (119.24 ± 0.37) use, Vitremer (121.56 ± 0.92) as well as the control group (141.88 ± 1.09) in that order. And there was a statistically significant difference found between the groups (p <0.001). Tukey's honestly significant difference (HSD) was employed in an overall comparison of mean areas of enamel demineralization, which depicted that differences were significant statistically with the exception of group III and group IV. CONCLUSION: The current research came to a conclusion that the Transbond Plus color change adhesive group was more potent in significant inhibition of demineralization areas in comparison to GC Fuji Ortho LC group and Vitremer group. CLINICAL SIGNIFICANCE: In course of fixed orthodontic therapy, demineralization of enamel is an inherent occurrence. Multiple approaches are being continually developed to avoid the formation of white spot lesions (WSLs) that compromise esthetics and cause deprived remineralization that enhances the menace of dental caries. Bonding agents that can release fluorides are thus considered highly efficacious.

Reconstruction of Craniofacial Bone Defects with Autologous Human Bone Marrow Stem Cells and Autogenous Bone Grafts: A Case Report with Review of Literature.

Reconstruction of craniofacial bony defects has always been a challenging task for the surgeons over the years. The science of reconstructing such defects is of at most importance to craniofacial and plastic surgeons due to its relevance in facial aesthetics function as well as prerequisite procedure for continuing other surgical procedures. The main goal of the reconstruction of the craniofacial defects is to reduce the morbidity by restoring the facial form and aesthetics, as well as a good function of the facial structures by achieving a reasonable occlusion and articulation. Although significant improvements have occurred during the last few decades, challenges still exist as to what type of reconstruction to be carried out with regard to techniques and the type and quality of materials of choice to be used. As decades progressed, the advancement in surgical techniques and the variety of reconstruction methods have definitely improved the quality of life. This article reviews the method of bony reconstruction of craniofacial defects using autologous human bone marrow stem cells and autologous bone grafts and its modification, which includes much recent tissue engineering techniques and regenerative medicine, thereby replacing older techniques by biological substitutes, which can restore improve and maintain orofacial function and aesthetics.

Violation of Stokes-Einstein and Stokes-Einstein-Debye relations in polymers at the gas-supercooled liquid coexistence.

Molecular dynamics simulations are performed on a system of model linear polymers to look at the violations of Stokes-Einstein (SE) and Stokes-Einstein-Debye (SED) relations near the mode coupling theory transition temperatureTcat three (one higher and two lower) densities. At low temperatures, both lower density systems show stable gas-supercooled-liquid coexistence whereas the higher density system is homogeneous. We show that monomer density relaxation exhibits SE violation for all three densities, whereas molecular density relaxation shows a weak violation of the SE relation nearTcin both lower density systems. This study identifies disparity in monomer mobility and observation of jumplike motion in the typical monomer trajectories resulting in the SE violations. In addition to the SE violation, a weak SED violation is observed in the gas-supercooled-liquid coexisting domains of the lower densities. Both lower density systems also show a decoupling of translational and rotational dynamics in this polymer system.

Lichen scrofulosorum: An uncommon manifestation of a common disease.

Tuberculid is a cutaneous immunologic reaction to the presence of tuberculosis (TB), which is often occult, elsewhere in the body or their fragments released from a different site of manifest or past tuberculous infection. These eruptive lesions are due to hematogenous dissemination of bacilli in a host with a high degree of immunity against Mycobacterium tuberculosis. Although rare, these specific lesions are important diagnostic markers of TB. Lichen scrofulosorum (LS) is one of the recognized tuberculids, usually seen in children and young adults. We report a female who was diagnosed with LS and was treated appropriately. This case report highlights the uncommon, easily misdiagnosed but readily treatable case of LS and emphasizes its early diagnosis, detection, and treatment of otherwise an occult systemic TB in young patients.

Two Cases of Lingual Arteriovenous Malformations with Comorbidities Treated by Glue Embolization: A Report with Review of Literature.

Arteriovenous malformations (AVMs) involving the tongue are uncommon lesions in the head and neck region. They present with bleeding that can be massive and life-threatening apart from debilitating symptoms of pain, ulcers, difficulty in phonation or swallowing. Various therapeutic approaches have been used in their management-surgery, endovascular embolization, radiation and ablation procedures like laser ablation. We report two patients-a 34 year-old man and 56 year-old female who presented with massive bleeding due to lingual AVM and had comorbidities as liver cirrhosis and chronic medical renal disease respectively, and treated with glue embolization, with a review of the literature.

Symmetry determined superpixels for efficient lesion segmentation of ischemic stroke from MRI.

Non-invasive, quantitative and robust identification of ischemic stroke and estimation of injury extent is essential for assisting neuroradiologists. Manual Iesion delineation techniques are susceptible to subjective errors and therefore computer aided preliminary screening of necrosis is warranted. Superpixel based segmentation has gained importance in the recent past by reducing the computational complexity and preserving the characteristics of a group of pixels with similar properties. Axial and coronal MR images of brain exhibit the important feature of symmetry which was integrated with superpixels for segmenting ischemic Iesion. This method was evaluated on a challenging 10 patient data set along with MICCAI challenge data of 28 patients yielding promising results. Proposed symmetry determined superpixel based method demonstrated accuracy close to manual Iesion demarcation with high performance indices with average sensitivity of 82.32%, specificity of 93.7% and Dice similarity score of81.14%.

Dental age estimation using Willems method: A digital orthopantomographic study.

UNLABELLED: In recent years, age estimation has become increasingly important in living people for a variety of reasons, including identifying criminal and legal responsibility, and for many other social events such as a birth certificate, marriage, beginning a job, joining the army, and retirement. OBJECTIVES: The aim of this study was to assess the developmental stages of left seven mandibular teeth for estimation of dental age (DA) in different age groups and to evaluate the possible correlation between DA and chronological age (CA) in South Indian population using Willems method. MATERIALS AND METHODS: Digital Orthopantomogram of 332 subjects (166 males, 166 females) who fit the study and the criteria were obtained. Assessment of mandibular teeth (from central incisor to the second molar on left quadrant) development was undertaken and DA was assessed using Willems method. RESULTS AND DISCUSSION: The present study showed a significant correlation between DA and CA in both males (r = 0.71 and females (r = 0.88). The overall mean difference between the estimated DA and CA for males was 0.69 ± 2.14 years (P < 0.001) while for females, it was 0.08 ± 1.34 years (P > 0.05). Willems method underestimated the mean age of males by 0.69 years and females by 0.08 years and showed that females mature earlier than males in selected population. The mean difference between DA and CA according to Willems method was 0.39 years and is statistically significant (P < 0.05). CONCLUSION: This study showed significant relation between DA and CA. Thus, digital radiographic assessment of mandibular teeth development can be used to generate mean DA using Willems method and also the estimated age range for an individual of unknown CA.

Similarities between protein folding and granular jamming.

Grains and glasses, widely different materials, arrest their motions upon decreasing temperature and external load, respectively, in common ways, leading to a universal jamming phase diagram conjecture. However, unified theories are lacking, mainly because of the disparate nature of the particle interactions. Here we demonstrate that folded proteins exhibit signatures common to both glassiness and jamming by using temperature- and force-unfolding molecular dynamics simulations. Upon folding, proteins develop a peak in the interatomic force distributions that falls on a universal curve with experimentally measured forces on jammed grains and droplets. Dynamical signatures are found as a dramatic slowdown of stress relaxation upon folding. Together with granular similarities, folding is tied not just to the jamming transition, but a more nuanced picture of anisotropy, preparation protocol and internal interactions emerges. Results have implications for designing stable polymers and can open avenues to link protein folding to jamming theory.

Hyperbaric oxygen-A new horizon in treating cyclophosphamide-induced hemorrhagic cystitis.

Hemorrhagic cystitis consists of acute or insidious diffuse bleeding from the bladder mucosa. It can be caused by radiation, drugs, autoimmune diseases, viral and bacterial infections, etc. Hemorrhagic cystitis is a well-recognized complication of cyclophosphamide therapy and it can be potentially fatal. We discuss two cases of cyclophosphamide-induced hemorrhagic cystitis where outcome of conventional management was not satisfactory and a novel therapy using hyperbaric oxygen was used. Hyperbaric oxygen therapy (HBOT) reduces inflammation, stimulates neoangiogenesis, maintains tissue oxygenation and heals tissue hypoxia and radio necrosis. Patients received 100% oxygen in a hyperbaric chamber at 2.5 atmosphere absolute (ATA) for 90 minutes, 5 days a week. One patient was given 36 sessions and the other was given 19 sessions of HBOT. HBOT resulted in complete cessation of bleeding; no side effect was noted during the course of therapy. There was no relapse after 12 months of cessation of treatment. In future, this form of therapy can offer a safe alternative in the treatment of cyclophosphamide-induced hemorrhagic cystitis.

Single-chain dynamics in a semidilute polymer solution under steady shear.

We use Brownian dynamics computer simulations to investigate single-chain dynamics in a semidilute polymer solution undergoing a steady, uniform shear flow. In the presence of the shear flow, the system used in the present study exhibits anisotropic structure factors, often referred to as butterfly patterns, which rotate with increasing shear rate [P. P. Jose and G. Szamel, J. Chem. Phys. 127, 114905 (2007)]. The rotation of these patterns correlates with shear thinning of the solution. In order to elucidate the microscopic origin of this behavior, we have investigated the change in the single-chain dynamics in the solution: We have focused on the relaxation of the end-to-end vector, the Rouse modes, and the radius of gyration tensor. In equilibrium and for small shear rates, these quantities show double exponential relaxation. With increasing shear rate, they show oscillatory relaxation, which hints at the tumbling motion of the chain. In the high shear rate regime, the frequency of the oscillations of the end-to-end vector autocorrelation function shows a power law dependence on the shear rate. We have compared the single-chain dynamics in the semidilute solution with that in a dilute solution. An analysis of the instantaneous values of the radius of gyration tensor, the end-to-end distance, and the normal stress along the system's trajectory reveals a synchronization of the fluctuations of these quantities.

Structure of a semidilute polymer solution under steady shear.

We use Brownian dynamics computer simulations to investigate the structure of a semidilute polymer solution undergoing a steady, uniform shear flow. We find that the contributions to structure factor from intra- and interchain correlations, which cancel each other almost completely for an equilibrium semidilute solution, are modified in different ways by the shear flow. Incomplete cancellation of these contributions leads to anisotropic patterns that resemble those observed in light scattering experiments on sheared semidilute solutions [Wu et al., Phys. Rev. Lett. 66, 2408 (1991)]. For small wave vectors the structure factor change is dominated by the interchain contribution. We also monitor the distortion of the pair correlation function and show that for small distances it is dominated by the intrachain contribution. Finally, we investigate nonlinear shear viscosity and find that, like the short-distance part of the distortion of the pair correlation function, it is predominantly of intrachain origin.

Multiple short time power laws in the orientational relaxation of nematic liquid crystals.

Relaxation in the nematic liquid crystalline phase is known to be sensitive to its proximity to both isotropic and smectic phases. Recent transient optical Kerr effect (OKE) studies have revealed, rather surprisingly, two temporal power laws at short to intermediate times and also an apparent absence of the expected exponential decay at longer times. In order to understand this unusual dynamics, we have carried out extensive molecular dynamics simulations of transient OKE and related orientational time correlation functions in a system of prolate ellipsoids (with aspect ratio equal to 3). The simulations find two distinct power laws, with a crossover region, in the decay of the orientational time correlation function at short to intermediate times (in the range of a few picoseconds to a few nanoseconds). In addition, the simulation results fail to recover any long time exponential decay component. The system size dependence of the exponents suggests that the first power law may originate from the local orientational density fluctuations (like in a glassy liquid). The origin of the second power law is less clear and may be related to the long range fluctuations (such as smecticlike density fluctuations)--these fluctuations are expected to involve small free energy barriers. In support of the latter, the evidence of pronounced coupling between orientational and spatial densities at intermediate wave numbers is presented. This coupling is usually small in normal isotropic liquids, but it is large in the present case. In addition to slow collective orientational relaxation, the single particle orientational relaxation is also found to exhibit slow dynamics in the nematic phase in the long time.

Complete breakdown of the Debye model of rotational relaxation near the isotropic-nematic phase boundary: effects of intermolecular correlations in orientational dynamics.

The Debye-Stokes-Einstein (DSE) model of rotational diffusion predicts that the orientational correlation times tau l vary as [l(l+1)]-1, where l is the rank of the orientational time correlation function (given in terms of the Legendre polynomial of rank l). One often finds significant deviation from this prediction, in either direction. In supercooled molecular liquids where the ratio tau 1/tau 2 falls considerably below 3 (the Debye limit), one usually invokes a jump diffusion model to explain the approach of the ratio tau 1/tau 2 to unity. Here we show in a computer simulation study of a standard model system for thermotropic liquid crystals that this ratio becomes much less than unity as the isotropic-nematic phase boundary is approached from the isotropic side. Simultaneously, the ratio tau 2/eta, eta, being the shear viscosity of the liquid, becomes much larger than the hydrodynamic value near the I-N transition. We also analyze the breakdown of the Debye model of rotational diffusion in ratios of higher order orientational correlation times. We show that the breakdown of the DSE model is due to the growth of orientational pair correlation and provide a mode coupling theory analysis to explain the results.

Universal power law in the orientational relaxation in thermotropic liquid crystals.

We observe a surprisingly general power law decay at short to intermediate times in orientational relaxation in a variety of model systems (both calamitic and discotic, and also lattice) for thermotropic liquid crystals. As all these systems transit across the isotropic-nematic phase boundary, two power law relaxation regimes, separated by a plateau, emerge, giving rise to a steplike feature (well known in glassy liquids) in the single-particle second-rank orientational time correlation function. In contrast to its probable dynamical origin in supercooled liquids, we show that the power law here can originate from the thermodynamic fluctuations of the orientational order parameter, driven by the rapid growth in the second-rank orientational correlation length.

Anomalous glassy relaxation near the isotropic-nematic phase transition.

Dynamical heterogeneity in a system of Gay-Berne ellipsoids near its isotropic-nematic (I-N) transition, and also in an equimolar mixture of Lennard-Jones spheres and Gay-Berne ellipsoids in deeply supercooled regime, is probed by the time evolution of non-Gaussian parameters (NGP). The appearance of a dominant second peak in the rotational NGP near the I-N transition signals the growth of pseudonematic domains. Surprisingly, such a second peak is instead observed in the translational NGP for the glassy binary mixture. Localization of orientational motion near the I-N transition is found to be responsible for the observed anomalous orientational relaxation.

Anomalous viscoelasticity near the isotropic-nematic phase transition in liquid crystals.

Recent optical Kerr effect experiments have shown that orientational relaxation of nematogens shows a pronounced slow down of the response function at intermediate times and also a power law decay near the isotropic-nematic (I-N) transition. In many aspects, this behavior appears to be rather similar to the ones observed in the supercooled liquid near-glass transition. We have performed molecular dynamics simulations of model nematogens (Gay-Berne with aspect ratio 3) to explore the viscoelasticity near the I-N transition and also investigated the correlation of viscoelasticity (if any) with orientational relaxation. It is found that although the viscosity indeed undergoes a somewhat sharper than normal change near the I-N transition, it is not characterized by any divergence-like behavior (like the ones observed in the supercooled liquid). The rotational friction, on the other hand, shows a much sharper rise as the I-N transition is approached. Interestingly, the probability distribution of the amplitude of the three components of the stress tensor shows anisotropy near the I-N transition-similar anisotropy has also been seen in the deeply supercooled liquid. Frequency dependence of viscosity shows several unusual behaviors: (a) There is a weak, power law dependence on frequency [eta(')(omega) approximately omega(-alpha)] at low frequencies and (b) there is a rapid increase in the sharp peak observed in eta(')(omega) in the intermediate frequency on approach to the I-N transition density. These features can be explained from the stress-stress time correlation function. The angular velocity correlation function also exhibits a power law decay in time. The reason for this is discussed.