First Dental Visit: Age Reasons Oral Health Status and Dental Treatment Needs among Children Aged 1 Month to 14 Years.

Aim: The aim of this study was to see the age and also the reasons for the child's first dental visit and to assess the oral health status and treatment desires. Materials and methods: The study involved 133 children aged between 1 month and 14 years, who reported to the department of pediatric and preventive dentistry. All parents/legal guardians of the study participants gave written consent for participation in the study. Information on the child's age and reason for the dental visit were collected from a questionnaire given to parents. The children's dental condition was assessed by decayed, missing, and filled teeth (dmft) and DMFT values. Statistical analysis used: Statistical Package for Social Sciences (SPSS) version 21 and categorical data were compared by using Chi-square test. The level of significance was set at 0.05. Result: Age of the child for first dental visit was male: 85.7% at 9 years and female: 75.00% at 4 years. Majority of children who visited the dentist were age 7 years. The most common chief complaint about the primary visit was caries, and the second was tooth pain. Conclusion: Children report for the primary dental visit most commonly solely after 7 years and for complaints like caries and tooth pain. Children make their first dental visit too late (usually at the age of 7 years) in reference to medical recommendations (between 6 and 12 months of life). More of restoration was the treatment of need by 47.00%. The results of this study indicate unhealthy oral health creating their first dental visit and low health awareness of parents and guardians. How to cite this article: Padung N. First Dental Visit: Age Reasons Oral Health Status and Dental Treatment Needs among Children Aged 1 Month to 14 Years. Int J Clin Pediatr Dent 2022;15(4):394-397.

Comparative Evaluation of Marginal Integrity of Three Esthetic Restorative Materials - An In-vitro Study.

CONTEXT: Microleakage is the major cause for the failure of dental restorations, especially in Class V cavities, as margins of such restorations are generally located in dentin or cementum. Microleakage evaluation is necessary as a means of evaluation of the marginal integrity of restorative materials. This would assist in developing techniques and materials that would reduce damage caused by the failure of the restorative marginal seal. AIM: The aim of this study is to analyze and compare the marginal integrity among three esthetic restorative materials, namely GC Fuji II LC, GC G-Aenial anterior composite resin, and GC Equia forte fil. SETTING AND DESIGN: Sixty orthodontically extracted caries-free premolar teeth with Class V restorations were divided into three groups. Microleakage was measured using an ordinal scale of 0-4, as given by Khera and Chan, in increasing order of dye penetration, which was observed under a microscope. MATERIALS AND METHODS: Study was conducted in sound human extracted premolars in which Standardized Class V cavities were prepared. Teeth were randomly and equally assigned to three groups (GC Fuji II LC, GC G-Aenial anterior composite resin, and GC Equia forte fil). Teeth were sectioned longitudinally into two halves using diamond discs and the sectioned halves of the teeth were evaluated for dye penetration under stereomicroscope. STATISTICAL ANALYSIS USED: Intergroup comparison of mean dye penetration scores were compared using the Kruskal-Wallis test along with post hoc pairwise comparison by Mann Whitney U test. The level of statistical significance was set at 0.05. RESULTS AND CONCLUSION: All the three groups (GC Fuji II LC, GC G-Aenial anterior composite resin, and GC Equia forte fil) tested showed microleakage at the tooth restoration interface. It was evident that microleakage was found to be highest with the Fuji II LC, both at occlusal and cervical levels. GC Equia forte exhibited the best performance in limiting microleakage around the restoration margins.

How arginine derivatives alter the stability of lipid membranes: dissecting the roles of side chains, backbone and termini.

Arginine (R)-rich peptides constitute the most relevant class of cell-penetrating peptides and other membrane-active peptides that can translocate across the cell membrane or generate defects in lipid bilayers such as water-filled pores. The mode of action of R-rich peptides remains a topic of controversy, mainly because a quantitative and energetic understanding of arginine effects on membrane stability is lacking. Here, we explore the ability of several oligo-arginines R[Formula: see text] and of an arginine side chain mimic R[Formula: see text] to induce pore formation in lipid bilayers employing MD simulations, free-energy calculations, breakthrough force spectroscopy and leakage assays. Our experiments reveal that R[Formula: see text] but not R[Formula: see text] reduces the line tension of a membrane with anionic lipids. While R[Formula: see text] peptides form a layer on top of a partly negatively charged lipid bilayer, R[Formula: see text] leads to its disintegration. Complementary, our simulations show R[Formula: see text] causes membrane thinning and area per lipid increase beside lowering the pore nucleation free energy. Model polyarginine R[Formula: see text] similarly promoted pore formation in simulations, but without overall bilayer destabilization. We conclude that while the guanidine moiety is intrinsically membrane-disruptive, poly-arginines favor pore formation in negatively charged membranes via a different mechanism. Pore formation by R-rich peptides seems to be counteracted by lipids with PC headgroups. We found that long R[Formula: see text] and R[Formula: see text] but not short R[Formula: see text] reduce the free energy of nucleating a pore. In short R[Formula: see text], the substantial effect of the charged termini prevent their membrane activity, rationalizing why only longer [Formula: see text] are membrane-active.

Do conservation strategies that increase tiger populations have consequences for other wild carnivores like leopards?

Most large carnivore populations are declining across their global range except in some well managed protected areas (PA's). Investments for conserving charismatic apex carnivores are often justified due to their umbrella effect on biodiversity. We evaluate population trends of two large sympatric carnivores, the tiger and leopard through spatially-explicit-capture-recapture models from camera trap data in Kanha PA, India, from 2011 to 2016. Our results show that the overall density (100 km-2) of tigers ranged between 4.82 ± 0.33 to 5.21 ± 0.55SE and of leopards between 6.63 ± 0.71 to 8.64 ± 0.75SE, with no detectable trends at the PA scale. When evaluated at the catchment scale, Banjar catchment that had higher prey density and higher conservation investments, recorded significant growth of both carnivores. While Halon catchment, that had lower prey and conservation investments, populations of both carnivores remained stable. Sex ratio of both carnivores was female biased. As is typical with large carnivores, movement parameter sigma (an index for range size), was larger for males than for females. However, sigma was surprisingly similar for the same genders in both carnivores. At home-range scale, leopards achieved high densities and positive growth rates in areas that had low, medium or declining tiger density. Our results suggest that umbrella-species conservation value of tigers is likely to be compromised at very high densities and therefore should not be artificially inflated through targeted management.

Molecular Mechanism of Polycation-Induced Pore Formation in Biomembranes.

Polycations are an attractive class of macromolecules with promising applications as drug/gene carriers and biocides. The chemical structure and concentration of a polycation determine its interaction with cellular membranes and, hence, are crucial parameters for designing efficient nontoxic polycations. However, the interaction of polycations with biomembranes at the molecular level and the corresponding free-energy landscape is not well understood. In this work, we investigate the molecular mechanism of interaction between a strong polycation substituted with alkyl moieties and zwitterionic membranes via long-time-scale all-atom molecular dynamics simulations and free-energy calculations combined with Langmuir monolayer, atomic force microscopy, and calcein-release experimental measurements. We found that the membrane activity of the polycation and its ability to induce pores in the membranes can be attributed to the polycation-induced changes in the bilayer organization, such as reduced membrane thickness, increased disorder of the acyl chains, reduced packing, and electrostatic field gradients between membrane leaflets. These changes facilitate the penetration of water into the membrane and the formation of aqueous defects/pores. The calculated free-energy profiles indicate that the polycation lowers the nucleation barrier for pore opening and the free energy for pore formation in a concentration-dependent manner. Above the critical coverage of the membrane, the polycation nucleates spontaneous pores in zwitterionic membranes. Our work demonstrates the potential of combining enhanced sampling methods in MD simulations with experiments for a quantitative description of various events in the polycation-membrane interaction cycle, such as strong adsorption on the membrane due to hydrophobic and electrostatic interactions, and pore formation.

Faster Simulations with a 5 fs Time Step for Lipids in the CHARMM Force Field.

The performance of all-atom molecular dynamics simulations is limited by an integration time step of 2 fs, which is needed to resolve the fastest degrees of freedom in the system, namely, the vibration of bonds and angles involving hydrogen atoms. The virtual interaction sites (VIS) method replaces hydrogen atoms by massless virtual interaction sites to eliminate these degrees of freedom while keeping intact nonbonded interactions and the explicit treatment of hydrogen atoms. We have modified the existing VIS algorithm for most lipids in the popular CHARMM36 force field by increasing the hydrogen atom masses at regular intervals in the lipid acyl chains and obtained lipid properties and pore formation free energies in very good agreement with those calculated in simulations without VIS. Our modified VIS scheme enables a 5 fs time step resulting in a significant performance gain for all-atom simulations of membranes. The method has the potential to make longer time and length scales accessible in all-atom simulations of membrane-protein complexes.

Metastable Prepores in Tension-Free Lipid Bilayers.

The formation and closure of aqueous pores in lipid bilayers is a key step in various biophysical processes. Large pores are well described by classical nucleation theory, but the free-energy landscape of small, biologically relevant pores has remained largely unexplored. The existence of small and metastable "prepores" was hypothesized decades ago from electroporation experiments, but resolving metastable prepores from theoretical models remained challenging. Using two complementary methods-atomistic simulations and self-consistent field theory of a minimal lipid model-we determine the parameters for which metastable prepores occur in lipid membranes. Both methods consistently suggest that pore metastability depends on the relative volume ratio between the lipid head group and lipid tails: lipids with a larger head-group volume fraction (or shorter saturated tails) form metastable prepores, whereas lipids with a smaller head-group volume fraction (or longer unsaturated tails) form unstable prepores.

Probing a Continuous Polar Defect: A Reaction Coordinate for Pore Formation in Lipid Membranes.

Various biophysical processes involve the formation of aqueous pores over lipid membranes, including processes of membrane fusion, antimicrobial peptide activity, lipid flip-flop, and membrane permeation. Reliable and efficient free-energy calculations of pore formation using molecular dynamics simulations remained challenging due to the lack of good reaction coordinates (RCs) for pore formation. We present a new RC for pore formation that probes the formation and rupture of a continuous polar defect over the membrane. Potential of mean force (PMF) calculations along the new RC rapidly converge and exhibit no hysteresis between pore-opening and pore-closing pathways, in contrast to calculations based on previous RCs. We show that restraints along the new RC may restrain the system tightly to the transition state of pore formation, rationalizing the absence of hysteresis. We observe that the PMF of pore formation in a tension-free membrane of dimyristoylphosphatidylcholine (DMPC) reveals a free-energy barrier for pore nucleation, confirming a long-hypothesized metastable prepore state. We test the influence of the lipid force field, the cutoff distance used for Lennard-Jones interactions, and the lateral membrane size on the free energies of pore formation. In contrast to PMF calculations based on previous RCs, we find that such parameters have a relatively small influence on the free energies of pore nucleation. However, the metastability of the open pore in DMPC may depend on such parameters. The RC has been implemented into an extension of the GROMACS simulation software. The new RC allows for reliable and computationally efficient free-energy calculations of pore formation in lipid membranes.

Assessment of Oral Status in Pediatric Patients with Special Health Care Needs receiving Dental Rehabilitation Procedures under General Anesthesia: A Retrospective Analysis.

INTRODUCTION: Dental problems serve as additional burden on the children with special health care needs (CSHCN) because of additional hospitalization pressure, they face for the treatment of various serious medical problems. These patients have higher incidence of dental caries due to increased quantity of sugar involved in the drug therapies and lower salivary flow in the oral cavity. Such patients are difficult to treat with local anesthesia or inhaled sedatives. Single-sitting dental treatment is possible in these patients with general anesthesia. Therefore, we conducted this retrospective analysis of oral health status of CSHCN receiving various dental treatments in a given population. MATERIALS AND METHODS: A total of 200 CSHCN of age 14 years or less reporting in the pediatric wing of the general hospital from 2005 to 2014 that underwent comprehensive dental treatment under general anesthesia were included in the study. Patients with history of any additional systemic illness, any malignancy, any known drug allergy, or previous history of any dental treatment were excluded from the study. Complete mouth rehabilitation was done in these patients under general anesthesia following standard protocols. Data regarding the patient's disability, type, duration, and severity of disability was collected and analyzed. All the results were analyzed by Statistical Package for the Social Sciences (SPSS) software. Chi-square test, Student's t-test, and one-way analysis of variance were used to assess the level of significance. RESULTS: Statistically significant results were obtained while analyzing the subject's decayed missing filled/decayed extracted filled teeth indices divided based on age. Significant difference was observed only in cases where patients underwent complete crown placement even when divided based on type of disability. While analyzing the prevalence, statistically significant results were observed in patients when divided based on their age. CONCLUSION: In CSHCN, dental pathologies and caries indices are increased regardless of the type or extent of disability. CLINICAL SIGNIFICANCE: Children with special health care needs should be given special oral health care, and regular dental checkup should be conducted as they are more prone to have dental problems.

Simulations of Pore Formation in Lipid Membranes: Reaction Coordinates, Convergence, Hysteresis, and Finite-Size Effects.

Transmembrane pores play an important role in various biophysical processes such as membrane permeation, membrane fusion, and antimicrobial peptide activity. In principal, all-atom molecular dynamics (MD) simulations provide an accurate model of pore formation in lipid membranes. However, the free energy landscape of transmembrane pore formation remains poorly understood, partly because potential of mean force (PMF) calculations of pore formation strongly depend on the choice of the reaction coordinate. In this study, we used umbrella sampling to compute PMFs for pore formation using three different reaction coordinates, namely, (i) a coordinate that steers the lipids in the lateral direction away from the pore center, (ii) the distance of a single lipid phosphate group from the membrane center, and (iii) the average water density inside a membrane-spanning cylinder. Our results show that while the three reaction coordinates efficiently form pores in membranes, they suffer from strong hysteresis between pore-opening and pore-closing simulations, suggesting that they do not restrain the systems close to the transition state for pore formation. The two reaction coordinates that act via restraining the lipids lead to more pronounced hysteresis compared with the coordinate acting on the water molecules. By comparing PMFs computed from membranes with different numbers of lipids, we observed significant artifacts from the periodic boundary conditions in small simulation systems. Further analysis suggests that the formation and disruption of a continuous hydrogen-bonding network across the membrane corresponds to the transition state for pore formation. Our study provides molecular insights into the critical steps of transmembrane pore formation, and it may guide the development of efficient reaction coordinates for pore formation.

In vitro Comparison of Impact of Different Bleaching Agents on the Microhardness of Enamel.

BACKGROUND: Various agents are used these days for increasing the esthetics. One such procedure is bleaching that offers various advantages, as it is minimal invasive and cheap option to color the teeth and remove stain. The altered enamel after the bleaching process shows surface demineralization and porosities. The present study aimed to evaluate the effect of different bleaching agents on the microhardness of enamel. MATERIALS AND METHODS: A total of 100 freshly human extracted maxillary premolar teeth were selected for the study. Teeth with sound tooth structure were included for the study. All the specimens were randomly divided into four groups with 25 specimens in each group depending upon the type of bleaching agent used: Group A, artificial saliva (Control group); Group B, 35% hydrogen peroxide (HP); Group C, 25% HP; Group D, 10% carbamide peroxide (CP). Knoop Hardness Number (KHN) was calculated at 24, 48-hour, and 7-week interval. RESULTS: Results showed no statistical significant differences between the microhardness of enamel of different groups (p < 0.005). A slight fall in the value of KHN was seen in all the groups, except for the control group, although the results were statistically nonsignificant (p > 0.005). CONCLUSION: Although nonsignificantly, all the bleaching solutions produced some amount of alterations in the microstructure of enamel. More studies with higher study groups and more advanced estimation technologies are required to minimize microstructure alterations and promote for better outcome of bleaching procedures.

Quantifying Lateral Inhomogeneity of Cholesterol-Containing Membranes.

Lateral inhomogeneity plays a critical role for many properties of cholesterol-containing membranes, yet the thermodynamic forces involved in inhomogeneity remain poorly understood. Based on coarse-grained simulations of cholesterol in four increasingly unsaturated phospholipids, we computed lateral density fluctuations and free energies of domain formation, and we quantitatively relate those to variations in the chemical potential of cholesterol. Our simulations suggest that the lateral organization is dominated by weak repulsive cholesterol interactions, leading to a significantly more homogeneous distribution as compared to a two-dimensional ideal gas. Hence, phospholipids provide a "good" solvent for cholesterol. Unexpectedly, the degree of unsaturation of the phospholipid has only a minor effect on the lateral inhomogeneity of cholesterol in binary lipid mixtures. These results provide a link between functional properties and thermal fluctuations in lipid membranes.